Resin window member for near-infrared sensor

Abstract

To provide a resin window member having resistance to scratch and a low birefringence characteristic, the resin window member being usable while presenting a severe heat resisting characteristic required for a near-infrared sensor and enduring an in-vehicle high-temperature and high-moisture environment.SOLUTION: In the resin window member for a near-infrared sensor according to the present invention, there is a formed boy in which a glass transition temperature is in the range of 115-150°C, the absolute value of a photoelastic coefficient is not larger than 10×10-12 Pa-1, the average transmission when the wavelength is at least 380 nm and is 660 nm at a maximum is at least 15%, the formed body including a region of 5 cm2 or more in which the absolute value of the in-plane phase difference when the wavelength is 850 nm is less than 20nm as a continuous projection area and being formed of a resin composition containing a thermoplastic resin formed by injection molding.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] FIELD OF THEINVENTION The present invention relates to a resin window member for a near-infrared sensor. For example, the resin window member for a near-infrared sensor of the present invention may include a polarizing element having a polarization separation function for use in a near-infrared sensor device. [Background technology]

[0002] In recent years, near-infrared rays are increasingly being used to recognize the distance of objects placed in space, for driving assistance in automobiles, and for spatial recognition when using virtual reality (VR) headsets. There are also increasing examples of applications in which a pattern is projected onto an object and the distortion of the reflected image is detected to capture the unevenness of the object and be used for face recognition (for example, Patent Document 1).

[0003] Distance measuring sensors use a mechanism in which a pulsed near-infrared laser beam is irradiated onto an object so that it can be used at night or in the dark, and a sensor detects the reflected, scattered, and returned light, detecting the distance based on the time it takes for the light to leave and return to the light receiving section, and the speed of light. Generally, this remote sensing technology uses the TOF (Time of Flight) technology of LiDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging). In addition, for face recognition, a small near-infrared laser of the VCSEL (Vertical Cavity Surface Emitting Laser) type is combined with a DOE (Diffractive Optical Element) to irradiate a dot pattern onto the face, and the unevenness of the face is identified from the change in the distance of the dots and the distortion of the dots, and it is used as a face recognition sensor.

[0004] Since such sensors use near-infrared rays, which cannot be seen by humans, the light from the spotlight does not dazzle observers in the area, and it also has the advantage of not spoiling the scenery.

[0005] Furthermore, if such a sensor is visible to an observer, the observer may feel uncomfortable being constantly watched by a camera, so by using a visible light cut filter in the transmission window of the sensor device, which is processed to transmit near-infrared light but not visible light, the discomfort felt by the driver can be reduced (Figure 1 shows an example configuration).

[0006] Cutting off visible light in this manner also has the effect of preventing erroneous recognition caused by the photoelectric sensor mistakenly detecting visible light.

[0007] On the other hand, when an object includes a specular reflection, an observer wears a specular reflecting part such as glasses, or an object that produces a specular reflection such as the surface of water is observed, the near-infrared light emitted from the projector is specularly reflected by these objects. In this case, if the light has low directivity and has a spread, when the spread light is reflected by the specular part and reaches the light receiving part of the near-infrared sensor, the optical path is different, which causes a problem of low distance measurement accuracy. To address this issue, it is known that by placing a linear polarization element in front of the projector and arranging another linear polarization element in front of the light receiving unit so that its transmission axis is perpendicular to that of the linear polarization element, the strong regular reflection light can be blocked by the linear polarization element in front of the light receiving unit, which makes it possible to suppress specular reflection and improve accuracy by measuring distances using diffuse and scattered light (see Patent Document 2). This configuration also makes it possible to somewhat suppress noise caused by external light such as sunlight. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2022 / 255187 [Patent Document 2] Patent No. 3270800 Summary of the Invention [Problem to be solved by the invention]

[0009] However, when using technology to color window members black as a means of blocking visible light, there are issues such as the transmittance varying depending on the thickness of the plate material, and scattering by the pigments used for coloring and birefringence by the coloring agents can disrupt the polarization state of the polarized light exiting and entering the window member, resulting in a decrease in noise suppression function and a decrease in detection accuracy.

[0010] Furthermore, if the resin composition contains carbon and hydrogen as its components, light in the near-infrared range is absorbed by the resin due to overtone absorption of the stretching vibration of CH, generating heat. In addition, the inside of the housing often becomes hot due to heat generation from the calculation chip that performs the distance measurement calculation process, and a resin window with low heat resistance could not withstand the usage environment. If it could not withstand a high-temperature environment, there would be problems such as deformation of the window material and deterioration of the resin due to heat, which increases haze and deteriorates the imaging characteristics.

[0011] As described above, when constructing a window member for a near-infrared sensor from a resin composition that is easier to process and more easily mass-produce than glass, resin compositions containing general resins such as acrylic resin and polycarbonate have been considered. However, these do not meet the required standards, and the configuration of a protective cover that meets these strict standards has not been fully considered.

[0012] SUMMARY OF THE PRESENT EMBODIMENTS The present invention has an object to provide a resin window member which has scratch resistance and low birefringence, and which is capable of withstanding the severe heat resistance required for a near-infrared sensor and the high temperature and high humidity environment inside a vehicle. [Means for solving the problem]

[0013] As a result of extensive research into solving the problems of the conventional technology described above, the inventors discovered that the problems could be solved by using a resin window component that satisfies certain characteristics, and thus completed the present invention.

[0014] That is, the present invention is as follows. [1] The glass transition temperature is in the range of 115 to 150°C, and the absolute value of the photoelastic coefficient is 10 x 10 -12 Pa -1 The average transmittance at wavelengths of 380 nm to 660 nm is 15% or more, and the absolute value of the in-plane retardation at a wavelength of 850 nm is less than 20 nm on average. The continuous projected area is 5 cm 2 The above includes a molded article made of a resin composition containing a thermoplastic resin formed by injection molding, A resin window member for a near-infrared sensor. [2] The resin window member for a near-infrared sensor according to [1], which has a haze of 1.5% or less at wavelengths of 800 nm to 1000 nm after a reliability test at 110° C. for 2000 hours. [3] The resin window member for a near-infrared sensor according to [1] or [2], having an M-scale Rockwell hardness of 90 or more. [4] In the region in which the average absolute value of the in-plane retardation at a wavelength of 850 nm is less than 20 nm, the difference between the average absolute value of the in-plane retardation at a wavelength of 810 nm and the average absolute value of the in-plane retardation at a wavelength of 850 nm is less than 5 nm. The resin window member for a near-infrared sensor according to any one of [1] to [3]. [5] The resin window member for a near-infrared sensor according to any one of [1] to [4], which is used in combination with a polarizing element having polarization separation ability in the near-infrared region and a near-infrared sensor, and is placed between a subject and the near-infrared sensor. [6] The resin window member for a near-infrared sensor according to any one of [1] to [5], having an average transmittance of 50% or more at a wavelength of 800 nm or more and 1000 nm or less, and an average transmittance of 5% or less at a wavelength of 380 nm or more and 660 nm or less. [7] The resin window member for a near-infrared sensor according to any one of [1] to [6], which has a convex or concave surface and a curved surface with a curvature radius of 5000 mm or less. [8] The glass transition temperature is in the range of 115 to 150°C, and the absolute value of the photoelastic coefficient is 10 x 10 -12 Pa -1 The molded article is made of a resin composition containing a thermoplastic resin formed by injection molding, and has an average transmittance of 15% or more at a wavelength of 380 nm or more and 660 nm or less, and includes a region in which the average absolute value of the in-plane retardation at a wavelength of 850 nm is less than 20 nm, and the continuous projected area of ​​the region is 50% or more relative to 100% of the projected area of ​​the entire molded article. A resin window member for a near-infrared sensor. [9] The resin window member for a near-infrared sensor according to any one of [1] to [8], wherein a polarizing element having a polarization separation function in the near-infrared region is attached to the molded body.

[10] The resin window member for a near-infrared sensor according to any one of [1] to [9], wherein the molded article has an acid component content of 100 ppm or less.

[11] The resin window member for a near-infrared sensor according to any one of [1] to

[10] , wherein the flexural strength of the molded article is 65 MPa or more.

[12] A protective cover for a headset housing, comprising the resin window member for a near-infrared sensor according to any one of [1] to

[11] .

[13] A protective cover for a LiDAR for distance measurement, comprising the resin window member for a near-infrared sensor according to any one of [1] to

[11] .

[14] A protective cover for a LiDAR cover for face authentication, comprising the resin window member for a near-infrared sensor according to any one of [1] to

[11] .

[15] A near-infrared sensor comprising the resin window member for a near-infrared sensor according to any one of [1] to

[14] . Effect of the Invention

[0015] According to the present invention, it is possible to provide a resin window member that can be used in near-infrared sensors, which has scratch resistance and low birefringence characteristics, and can also withstand the strict heat resistance characteristics required of near-infrared sensors and the high temperature and high humidity environment inside a vehicle. By using the resin window member of the present invention, a near-infrared sensor can be provided that has sufficient scratch resistance as a cover, is capable of capturing clear near-infrared images (including videos), and has the imaging performance to block specularly reflected light and thereby enable observation of the eyes of a driver wearing glasses, while still being able to be stably used even in the high temperature and high humidity environment inside a vehicle.Furthermore, because it is a resin window member, there is a high degree of freedom in shape, and it is possible to form curved surfaces to match the design of the interior of the vehicle. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a conceptual diagram illustrating a configuration of a general near-infrared sensor. [Diagram 2] FIG. 1 is a schematic diagram illustrating the configuration of a wire grid polarizer (WGF). [Diagram 3] This is a schematic diagram of an optical system that explains the influence of birefringence of a protective cover in a near-infrared sensor that uses a wire grid polarization element that has a polarization separation function even for wavelengths in the near-infrared range. [Figure 4] FIG. 2 is a conceptual diagram illustrating an evaluation method using a near-infrared camera in an embodiment. [Diagram 5] FIG. 2 is a schematic diagram showing the appearance of a molded piece obtained from a mold used in the examples and the area where birefringence was measured. [Figure 6] FIG. 1 is a schematic diagram showing the appearance of a molded piece obtained from the mold used in Example 9 and the area where birefringence was measured. [Figure 7] FIG. 2 is a schematic diagram illustrating a molded piece supporting jig used in the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, the embodiment for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail, but the present invention is not limited to the following description and can be modified in various ways within the scope of the gist. In addition, in the description of the polarization state and phase difference of light, the state represented by concepts such as linear polarization, circular polarization, elliptical polarization, and 1 / 4λ phase difference generally means a wide state having a certain range. Therefore, the essential effect of the present invention is not hindered by these errors. In addition, the phase difference generated in each optical element is the phase difference with respect to light of wavelength λ, and the wavelength λ can be selected from any wavelength in the visible light range, for example, λ=587.6 nm, but is not limited thereto.

[0018] [Resin window material for near-infrared sensors] The resin window member for a near-infrared sensor of this embodiment (hereinafter, may be simply referred to as a "resin window member") has a glass transition temperature in the range of 115 to 150° C. and an absolute value of a photoelastic coefficient of 10×10 -12 Pa -1 The average transmittance at wavelengths of 380 nm or more and 660 nm or less is 15% or more (preferably 20% or more), and the absolute value of the in-plane retardation at a wavelength of 850 nm is less than 20 nm on average. The continuous projected area of ​​the region is 5 cm 2 The present invention also includes a molded article made of a resin composition containing a thermoplastic resin formed by injection molding. The resin window member for a near-infrared sensor of this embodiment may be a resin window member consisting of only the molded body, or may be a resin window member consisting of the molded body and another member (for example, a polarizing element having a polarization separation function in the near-infrared region). The other member may be one or more. The mass ratio of the molded body to 100 parts by mass of the resin window member for a near-infrared sensor of this embodiment is preferably 50 parts by mass or more, more preferably 70 parts by mass or more. The resin window member for a near-infrared sensor of this embodiment is preferably a composite in which one other member (for example, a polarizing element having a polarization separation function in the near-infrared region) is bonded onto one surface of the molded body. The resin window member for an infrared sensor may be a resin window member for use in an infrared sensor (that is, a resin window member for an infrared sensor).

[0019] The resin window member for a near-infrared sensor of the present embodiment is disposed between a projector of a near-infrared sensor and / or a near-infrared camera and a subject, has transparency to light with a wavelength in the near-infrared region, has a glass transition temperature Tg of 115° C. to 150° C., and has an absolute value of a photoelastic coefficient of 10×10 -12 Pa -1 The molded article is characterized in that it includes the following molded article. The molded article has an average transmittance of 15% or more (preferably 20% or more) at wavelengths of 380 nm or more and 660 nm or less. The molded article has a continuous projected area of ​​5 cm2 where the absolute value of the in-plane retardation at a wavelength of 850 nm is less than 20 nm on average. 2 Including the above.

[0020] <Characteristics of resin window materials for near-infrared sensors> -shape- The shape of the resin window member is not particularly limited. It may be a dome-shaped shape or a shape obtained by bending a sheet into a curved surface. The resin window member preferably has a convex or concave surface. The resin window member may have a convex or concave surface in an area including the optical axis other than a flat surface within the effective surface. Here, the optical axis refers to a straight line connecting the rotational symmetry axes of the high-pole elements of the optical system, and corresponds to a straight line connecting the rotational symmetry axes of each lens when the mechanism includes a near-infrared camera. In the case of a projector, it also refers to a straight line connecting the rotational symmetry axes of each lens. In addition, when the resin window member in front of the projector and the resin window member in front of the near-infrared camera are made separately, it refers to the optical axis of the projector and the optical axis of the near-infrared camera, respectively. The resin window member may also be given a function as a lens. The resin window member may have a spherical shape, an aspherical shape, or a free-form surface shape. Within the effective surface, the resin window member may have a spherical shape, an aspherical shape, or a free-form surface shape. The resin window member may also have a cylindrical shape that forms a curved surface only on one axis.

[0021] -size- The size of the resin window member is not particularly limited, however, in consideration of ease of manufacture, the length in the major axis direction is preferably 1 cm or more and 200 cm or less, more preferably 3 cm or more and 100 cm or less, and even more preferably 5 cm or more and 50 cm or less.

[0022] -Thickness- The thickness of the resin window member in the direction in which light passes is not particularly limited. When used simply as a cover, a thin wall is preferable to avoid the effects of light refraction, but a constant thickness is preferable in consideration of ease of manufacture and impact resistance. A uniform thickness of 0.1 mm to 20 mm is preferable, 0.5 mm to 10 mm is more preferable, and 1.0 mm to 6 mm is even more preferable. Furthermore, when the resin window member is intended to function as a front lens of a camera, the thickness should take into consideration ease of molding, and the thickness within the effective surface through which the imaging light passes is preferably 0.5 mm or more and 15 mm or less, more preferably 1.0 mm or more and 10 mm or less, and even more preferably 1.5 mm or more and 6 mm or less.

[0023] -Curvature radius- The resin window member preferably has a curved surface, and the curved surface preferably has a radius of curvature R of 5000 nm or less. The radius of curvature within the curved surface may be the same, or may include portions with different radii of curvature. The resin window member preferably has a convex or concave surface and a curved surface with a radius of curvature of 5000 mm or less. When the resin window member is given a curvature, it can be determined using a radius of curvature R, which is a standard representing the degree of the curved shape, but this is not particularly limited. Except for the radius of curvature R=∞, where the shape is flat, the radius of curvature R is preferably 10 mm or more and 5000 mm or less. More preferably, it is 20 mm or more and 2000 mm or less, even more preferably, it is 35 mm or more and 1500 mm or less, and particularly preferably, it is 40 mm or more and 800 mm or less. Dashboards, meter clusters, and other displays in a vehicle are often designed to have a curved shape so that the sense of distance from the driver's eyes is equal. Therefore, by making the shape within this range, it is possible to give a curved surface that matches the shape of the equipment in the vehicle, and it is possible to mold a resin window member that has high shape accuracy and suppresses the occurrence of birefringence at the end. When the thickness of the resin window component is not uniform and a lens function is to be imparted, a small radius of curvature makes molding difficult and also tends to result in large birefringence at the ends, making it difficult to correct aberrations in the optical system. Therefore, it is preferable to design the component appropriately while taking a balance into consideration. When the resin window member has an aspheric shape, the surface shape can be a rotationally symmetric aspheric surface in which the surface sag amount z satisfies the following formula.

number

[0024] -In-plane phase difference- In the resin window member of this embodiment, the average absolute value of the in-plane retardation at a wavelength of 850 nm in the effective plane is preferably 50 nm or less, more preferably 30 nm or less, even more preferably 20 nm or less, even more preferably 10 nm or less, and particularly preferably 6 nm or less. By using a resin window member in such a range, it is possible to maintain uniform polarization separation over the entire imaging range in the near-infrared sensor including the resin window member of this embodiment without impeding the function of a polarizing element having a polarization separation function for light with wavelengths in the near-infrared range (hereinafter, sometimes referred to as a near-infrared compatible polarizing element), and it is possible to obtain distance measurement data with good contrast over the entire imaging range without light blowout. Here, the effective surface of the resin window member refers to the area in which, when the resin window member is incorporated into the housing of the near-infrared sensor, the transmittance of light of 800 to 1000 nm is 20% or more, which can be measured by the method described in the examples described later, and the maximum area is the surface that includes the maximum movement range of the near-infrared camera of the near-infrared sensor and the spotlight that irradiates light of near-infrared wavelengths. Specifically, the in-plane retardation at a wavelength of 850 nm can be measured by the method described in the Examples below.

[0025] The molded article contained in the resin window member in this embodiment has a continuous projected area of ​​5 cm2 where the absolute value of the in-plane retardation at a wavelength of 850 nm is less than 20 nm on average (preferably 20 nm or less, more preferably 10 nm or less, and particularly preferably 6 nm or less). 2 It is preferable that the thickness of the plate is 10 cm or more. 2 It is preferable that the length of the plate is 15 cm or more. 2 It is preferable that the thickness is 20 cm or more, and particularly preferable that the thickness is 20 cm or more. 2 For example, considering that the camera and projector are moved by the driver's extension, posture, etc., it is preferable that the area includes the area multiplied by the driving distance. In addition, there is no particular upper limit to the continuous projected area, but it is recommended that the installation space including the camera and projector is 250 cm2. 2 In addition, considering the ease of manufacturing, 1000 cm 2It is preferable that the above-mentioned region is an area on the surface of the molded body. The above molded product (for example, the projected area in any direction is 5 cm 2 The molded article preferably includes a region in which the average absolute value of the in-plane retardation at a wavelength of 850 nm is less than 20 nm (preferably 20 nm or less, more preferably 10 nm or less, and particularly preferably 6 nm or less) in a continuous projected area of ​​50% or more, more preferably 60% or more, even more preferably 70% or more, and particularly preferably 80% or more of the entire projected area of ​​the molded article. The region may be 100% or less, less than 100%, or 99% or less. Here, the term "continuous" in the continuous projected area refers to a plane that is not divided and can be surrounded by a single line. The projected area refers to the area of ​​the shape of the entire molded body or a partial region of the molded body projected onto a horizontal plane when the molded body removed from the resin window member is placed on a horizontal plane and parallel light parallel to the direction of gravity is irradiated from a point vertically above at infinity (i.e., parallel projected area). The continuous projected area of ​​the region in which the absolute value of the in-plane retardation at a wavelength of 850 nm is less than 30 nm on average may be measured by placing the molded body so that the projected area is maximized. The projected area of ​​the entire molded body refers to the area of ​​the projection of the entire molded body when the molded body is placed so that the continuous projected area of ​​the region in which the absolute value of the in-plane retardation at a wavelength of 850 nm is less than 20 nm on average is maximized. The above-mentioned region in which the absolute value of the in-plane retardation at a wavelength of 850 nm is less than 20 nm on average preferably includes a region through which light from a light source passes and a region through which light entering a camera passes when used as a near-infrared sensor. In the above molded article, the region in which the average absolute value of the in-plane retardation falls within the above range is preferably a region that includes the surface of the resin window member. Examples of a method for making the continuous projected area of ​​regions in which the absolute value of the in-plane retardation at a wavelength of 850 nm is less than 20 nm on average fall within the above range include a method for producing a molded body having an area larger than the above area using a molded body made of a resin composition preferred in the present invention, which will be described later, and a method for producing a molded body using a molded body in which a monomer poured into a mold is solidified by a photocuring reaction or a thermosetting reaction. In addition, when coating or applying ink to the surface of a molded body, the presence of a light-scattering component disturbs the polarized light, so it is preferable to use a coating or ink having a low haze at 850 nm that can be measured by the method described in the Examples below.

[0026] -Wavelength dispersion of in-plane retardation- In the molded article included in the resin window member of this embodiment, in the above-mentioned region where the absolute value of the in-plane retardation at a wavelength of 850 nm is less than 20 nm on average (preferably 10 nm or less, particularly preferably 6 nm or less), the difference between the average absolute value of the in-plane retardation at a wavelength of 810 nm and the average absolute value of the in-plane retardation at a wavelength of 850 nm is preferably 20 nm or less. More preferably, it is 15 nm or less, even more preferably 5 nm or less, and even more preferably less than 5 nm. Especially preferably, it is 2 nm or less. From the viewpoint of ease of manufacture, it is preferably 0.3 nm or more. By setting the above range, polarization is maintained over a wide wavelength range, even in the case of a light source that emits light with a wide wavelength distribution, such as an LED used in a floodlight, and the effects of the present invention are fully exerted, making it possible to capture clear images. As a method for achieving the above range, for example, a method of producing a molded body made of a resin composition preferred in the present invention described later can be mentioned. A polymer composed of monomers having the same birefringence sign when made into a homopolymer is preferred because it tends to have small dispersibility. In addition, when using a resin composition made by copolymerizing a plurality of monomers, it is preferred to adjust the copolymerization composition ratio of a monomer having a positive birefringence and a monomer having a negative birefringence when made into a homopolymer to an appropriate range.

[0027] -Glass transition temperature- The molded body contained in the resin window member in this embodiment preferably has a glass transition temperature (Tg) of 115° C. or higher and 150° C. or lower. The glass transition temperature of the molded body is 115°C or higher, ensuring heat resistance to the high temperature environment expected inside a vehicle and to heat generated by a computing chip that processes images (including video) captured by a camera. In addition, when the molded body is bonded to the housing of the near-infrared sensor with an adhesive or pressure sensitive adhesive, high heat resistance is also advantageous in terms of preventing peeling caused by the difference in dimensional change between the resin window member and the housing. Similarly, peeling can be prevented when the molded body in the resin window member is bonded to another member (e.g., a polarizing element). The glass transition temperature (Tg) is more preferably 120° C. or higher, further preferably 125° C. or higher, and most preferably 130° C. or higher. On the other hand, when the glass transition temperature (Tg) is 150° C. or lower, melt processing at extremely high temperatures is avoided, thermal decomposition of the resin, etc. is suppressed, and a good product can be obtained. From the viewpoint of further obtaining the above-mentioned effects, the glass transition temperature (Tg) is preferably 145° C. or lower, more preferably 140° C. or lower, and even more preferably 135° C. or lower. The glass transition temperature (Tg) can be determined by measurement in accordance with JIS-K7121. Specifically, it can be determined by the method described in the Examples below. The glass transition temperature of the molded article can be adjusted to the above-mentioned range, for example, by producing a molded article from a preferred resin composition in the present invention described below, and the glass transition temperature can be increased by imparting a ring structure to the main chain in the resin composition.

[0028] -Photoelastic coefficient CR- The absolute value |CR| of the photoelastic coefficient CR of the molded body included in the resin window member in this embodiment is 10.0×10 -12 Pa -1 It is preferable that the ratio is 6.0×10 or less, and more preferable that the ratio is 6.0×10 -12 Pa -1 More preferably, it is 3.0×10 -12 Pa -1 More preferably, it is 1.0×10-12 Pa -1 The following is the result. The photoelastic coefficient is described in various documents (for example, see Chemical Review, No. 39, 1998 (published by the Academic Press Center)) and is defined by the following formulas (ia) and (ib). It can be seen that the closer the photoelastic coefficient CR value is to zero, the smaller the change in birefringence due to external force is. |CR|=|Δn| / σR (ia) |Δn|=|nx-ny| (ib) (In the formula, CR is the photoelastic coefficient, σR is the tensile stress (unit: Pa), |Δn| is the absolute value of birefringence, nx is the refractive index in the stretching direction, and ny is the refractive index in the in-plane direction perpendicular to the stretching direction.) The absolute value |CR| of the photoelastic coefficient CR of the molded body contained in the resin window member of this embodiment is 10.0×10 -12 Pa -1 If the absolute value of the photoelastic coefficient |CR| is 6.0×10 or less, the photoelastic birefringence caused by the stress generated when fixing the resin window member to the housing and the dimensional change caused by the environmental change such as temperature can be kept low, so that a resin window member capable of capturing a clear image (video) can be obtained. If it is desired to omit the annealing process, which is a distortion relaxation process after molding, the absolute value of the photoelastic coefficient |CR| -12 Pa -1 Less than or equal to 3.0×10, more preferably -12 Pa -1 It is desirable that the thickness of the molded product is less than 1 mm. Such a molded product is preferable because the residual stress during molding is unlikely to occur as photoelastic birefringence. In addition, when a curved surface shape that matches the design of the car interior is preferred, the fact that photoelastic birefringence is unlikely to occur even when bending is performed is also favorable. The photoelastic coefficient CR is measured by cutting the molded article contained in the resin window member into small pieces and pressing it into a film using a vacuum compression molding machine. Specifically, the photoelastic coefficient CR can be determined by the method described in the Examples below. The absolute value of the photoelastic coefficient of the above-mentioned molded body can be adjusted to the above-mentioned range, for example, by producing a molded body from a resin composition preferred in the present invention described below, and it is preferable to adjust the copolymerization composition ratio of a monomer having a positive photoelastic coefficient and a monomer having a negative photoelastic coefficient when made into a homopolymer to an appropriate range.

[0029] -Molecular weight and molecular weight distribution- The molded article contained in the resin window member in this embodiment has a weight average molecular weight (Mw) in terms of polymethyl methacrylate measured by gel permeation chromatography (GPC) in the range of preferably 80,000 to 170,000, more preferably 90,000 to 170,000, even more preferably 100,000 to 150,000, and still more preferably 110,000 to 150,000. When the weight average molecular weight (Mw) is in the above range, the balance between mechanical strength and fluidity is excellent. The weight average molecular weight (Mw), number average molecular weight (Mn), and Z average molecular weight (Mz) of the molded product can be measured using the following apparatus and conditions. Measurement equipment: Tosoh Corporation gel permeation chromatography (HLC-8320GPC) Measurement conditions: Columns: One TSKguardcolumn SuperH-H, two TSKgel SuperHM-M, and one TSKgel SuperH2500, connected in series. Column temperature: 40℃ Developing solvent: tetrahydrofuran, flow rate: 0.6 mL / min, 2,6-di-t-butyl-4-methylphenol (BHT) was added as an internal standard at 0.1 g / L. Detector: RI (differential refractometer) detector Detection sensitivity: 3.0mV / min Sample: 0.02 g of resin window material dissolved in 20 mL of tetrahydrofuran Injection volume: 10μL Standard sample for calibration curve: The following 10 types of polymethyl methacrylate (PMMA Calibration Kit MM-10, manufactured by Polymer Laboratories) with known monodisperse weight peak molecular weights and different molecular weights are used. Weight peak molecular weight (Mp) Standard sample 1 1,916,000 Standard sample 2 625,500 Standard sample 3 298,900 Standard sample 4 138,600 Standard sample 5 60,150 Standard sample 6 27,600 Standard sample 7 10,290 Standard sample 8 5,000 Standard sample 9 2,810 Standard sample 10 850 Under the above conditions, the RI detection intensity is measured versus the elution time of the resin window member. Based on the calibration curves obtained by measuring the standard samples for the calibration curves, the weight average molecular weight (Mw), number average molecular weight (Mn), and Z average molecular weight (Mz) of the molded body are calculated, and the molecular weight distributions (Mw / Mn) and (Mz / Mw) are determined using these values.

[0030] -Average transmittance in the near infrared range- The resin window member in this embodiment desirably has high transparency to light with wavelengths in the near-infrared region, which generally refers to light with wavelengths in the region of 800 nm to 2500 nm. Specifically, the average transmittance at wavelengths of 800 nm to 1000 nm is preferably 50% or more, more preferably 70% or more, even more preferably 80% or more, and particularly preferably 85% or more. In this way, the high transmittance of light with wavelengths of 850 nm or 940 nm from near-infrared LEDs commonly used in near-infrared sensors and light with wavelengths of 915 nm or 940 nm from laser diodes (hereinafter referred to as LDs) that emit near-infrared light makes it possible to capture clear images. The average transmittance in the near infrared region can be determined by the method described in the Examples below. The average transmittance in the near-infrared region of the resin window member of this embodiment can be adjusted to the above-mentioned range by manufacturing the resin window member using a molded body made from a resin composition preferred in the present invention described below. Since the transmittance in this region includes an absorption region derived from the stretching vibration of carbon-hydrogen bonds (CH), the average transmittance in the near-infrared region can be increased by reducing the number of CH bonds and including components made of compounds partially having carbon-deuterium (CD) bonds or carbon-fluorine (CF) bonds.

[0031] -Average transmittance in the visible range- From the viewpoint of design and aesthetics that take into consideration the fact that observers and people around them dislike being constantly photographed, and in order to eliminate noise from external light, it is desirable to lower the transmittance for light with wavelengths in the visible range of 380 nm to 780 nm. As a method for lowering the transmittance in the visible range in this way, it is possible to control the transmittance by coloring or coating, which will be described later. Specifically, the average transmittance of the visible light region at wavelengths of 380 nm to 660 nm is preferably 10% or less, more preferably 5% or less, further preferably 3% or less, and particularly preferably 1% or less. The average transmittance in the visible region can be determined by the method described in the Examples below.

[0032] The average visible transmittance of the resin window member can be adjusted to the above-mentioned range by coloring the thermoplastic resin composition constituting the molded body black or by mixing fine particles that diffuse light, or by applying black ink to one side of the molded body. However, because the transmittance can change depending on the thickness, and polarization can be disrupted due to scattering by coloring components (pigments, etc.), it is preferable to cut visible light by applying a thin surface coating. More preferably, two polarizing elements having a polarization separation function only in the visible light region are arranged perpendicular to each other, or in the case of a near-infrared sensor using a polarizing element having a polarization separation function only in the near-infrared region, one polarizing element having a polarization separation function only in the visible light region is arranged perpendicular to the polarizing element, thereby making it possible to cut visible light. This configuration increases costs, but makes it possible to reduce the occurrence of birefringence and the deterioration of haze. The coloring method and the ink application method can be carried out as described below.

[0033] -Average visible transmittance of molded body- As described above, in order to avoid the occurrence of birefringence due to pigments in the colorant, the deterioration of haze, etc., the average transmittance in the visible region of the molded product is preferably high. Among the wavelengths in the visible light region, the average transmittance of the wavelengths of 380 nm to 660 nm is preferably 15% or more, more preferably 20% or more, further preferably 50% or more, and particularly preferably 80% or more.

[0034] -Haze in the near infrared region- The resin window member in this embodiment desirably has low haze in the near-infrared wavelength region (for example, a wavelength region of 800 nm to 1000 nm) used by the near-infrared sensor. Low haze makes it possible to obtain clear distance measurement data (including images and videos). Specifically, the haze is preferably 0.7% or less, more preferably 0.5% or less, further preferably 0.4% or less, and particularly preferably 0.3% or less. It can be evaluated by the method described in the Examples below. It is preferable that the haze in the near-infrared wavelength region (e.g., wavelength region of 800 nm to 1000 nm, wavelength of 800 nm to 1000 nm after reliability test for 2000 hours at 110°C) used in the near-infrared sensor of the above-mentioned molded body contained in the resin window member in this embodiment is also within the above range. When coloring the thermoplastic resin composition in the resin constituting the molding or in the coating ink, it is preferable not to use colorants that have a large scattering of light in the near infrared region, such as carbon black, silica, or titanium oxide particles. Even if they are used, it is preferable to use them in small amounts and to use them after micronizing them to a particle size smaller than the wavelength of the near infrared region. In addition, a method of increasing dispersibility in the resin composition (such as International Publication No. 2011 / 152449) may be applied. By using a light absorber that has a small scattering of light in the near infrared region, as described below, it is possible to adjust the transmittance of visible light to fall within the above-mentioned preferred range while keeping the haze in the near infrared region low.

[0035] -Appearance after high temperature and humidity reliability test- It is desirable that the above-mentioned average transmittance in the near infrared region and the average transmittance in the visible region satisfy the above-mentioned preferred ranges even after a reliability test in a high-temperature, high-humidity environment that simulates the use environment inside a vehicle. It is also desirable that the above-mentioned molded body included in the resin window member of this embodiment satisfy the above-mentioned preferred ranges of the average transmittance in the near infrared region and the average transmittance in the visible region even after a reliability test in a high-temperature, high-humidity environment that simulates the use environment inside a vehicle. The high-temperature, high-humidity environment may be an environment of 85°C and 85% RH for 1000 hours.

[0036] -Dimensional change after high temperature and humidity testing- It is desirable that the dimensional change is small even after a reliability test in a high-temperature, high-humidity environment that simulates the use environment inside a vehicle. The dimensional change here can be evaluated by the method described in the Examples below. It is preferably 0.7% or less, more preferably 0.5% or less, even more preferably 0.4% or less, and particularly preferably 0.3% or less. It is desirable that the molded body contained in the resin window member in this embodiment also has a small dimensional change even after a reliability test in a high-temperature, high-humidity environment that simulates the use environment inside a vehicle, and it is preferable that the dimensional change is within the above range. If the dimensional change in a high temperature and high humidity environment is small, the difference in dimensional change with the resin composition used as the housing will be small, which is desirable because peeling is less likely to occur at the adhesive surface interface between the resin window member of this embodiment and the housing. The reliability test in a high-temperature and high-humidity environment may be a test described in the Examples section below.

[0037] -Haze in the near infrared region after high-temperature aging test- It is preferable that the haze at wavelengths of 800 nm to 1000 nm after a reliability test in a high-temperature environment simulating the use environment inside a vehicle (for example, after a reliability test at 110°C for 2000 hours) is small. It is preferably 2.0% or less, more preferably 1.5% or less, even more preferably 1.0% or less, and particularly preferably 0.5% or less. It is preferable that a resin window member within such a range can be used without deformation, etc. Therefore, it is desirable that the molded body contained in the resin window member satisfies the preferred range shown for the glass transition temperature as the heat resistance temperature. It can be evaluated by the method described in the examples below. It is preferable that the above-mentioned molded body contained in the resin window member in this embodiment also has small haze at wavelengths of 800 nm to 1000 nm after reliability testing in a high-temperature environment simulating the usage environment inside a vehicle (for example, after a reliability test for 2000 hours at 110°C), and it is more preferable that it is in the above range. The reliability test in a high temperature environment may be a test described in the examples below. The haze at wavelengths of 800 nm to 1000 nm of the resin window component of this embodiment after reliability testing in a high-temperature environment can be adjusted to the above-mentioned range by appropriately controlling the method of manufacturing the molded body using the resin composition preferred in the present invention, the amount of antioxidants, heat stabilizers, etc. in the resin composition that constitutes the molded body, ink, coating, etc., and the amount of ultraviolet absorber that absorbs ultraviolet (UV) light that promotes deterioration of the resin.

[0038] -Evaluation of deformation after high-temperature aging test- It is preferable that the glass material can be used without deformation even after a reliability test in a high-temperature environment simulating an in-house use environment. Therefore, it is desirable that the heat resistance temperature satisfies the preferable range shown for the glass transition temperature above.

[0039] -Acid component amount- The molded body contained in the resin window member in this embodiment can be measured for the content of acid components that dissolve in the molded body, rather than the acid value due to the resin structure, using a measurement method using ion chromatography described in the examples below. The content of the acid component in the molded body is preferably 150 ppm or less, more preferably 100 ppm or less, further preferably 50 ppm or less, and particularly preferably 20 ppm or less. From the viewpoint of ease of production, it is preferable that it is 5 ppm or more. By using a molded body with a small amount of acid components in such a range as a resin window member, it is possible to maintain good adhesion of the adhesive surface and the adhesive surface even when it is used by bonding it to a housing. In addition, even when the molded body is mixed with another member (for example, a polarizing element having polarization separation performance in the near infrared region), it is possible to maintain good adhesion of the bonding surface. Specifically, even after repeated condensation and drying or after a reliability test under a high temperature and high humidity environment, the acid components dissolved in the resin window member do not dissolve into water or the like and affect the interface, so that problems such as contaminating the adhesive interface and the adhesive interface, lowering the quality of the image, and reducing adhesion are unlikely to occur. Furthermore, when the polarizing element is referred to as a wire grid polarizer, it is possible to suppress deterioration of the metal wires constituting the reflective surface related to the polarization separation described later. The method for adjusting the acid component content of the molded product to the above range includes, for example, a method using a resin composition preferred in the present invention and a method for producing the same, which will be described later. The amount of acid components can be reduced by using a resin composition made of a resin that does not include a cyclization step using a catalyst.

[0040] - Bending strength - When the molded body included in the resin window member of this embodiment is used by adhering it to a housing or pasting it with an optical film, it expands or contracts due to heat or water absorption, and at this time, bending stress acts due to the difference in dimensional changes between the resin window member and the housing or optical film. This can cause cracks or breaks in the resin window member, especially when the molded body has a curvature or has uneven thickness. In order to prevent such defects, it is preferable for the bending strength to be high. The bending strength is preferably 65 MPa or more, more preferably 75 MPa or more, and even more preferably 85 MPa or more. When the bending strength is in this range, the resin lens is less likely to crack even when the reflective polarizing element-attached lens is subjected to a reliability test. The upper limit of the bending strength is preferably 180 MPa or less, more preferably 160 MPa or less, and particularly preferably 130 MPa. It is difficult to achieve both heat resistance, low orientation birefringence, low photoelasticity and low birefringence, and bending strength, and a resin composition having a bending strength outside the above range is inferior in heat resistance and optical properties, leading to deterioration of the detection accuracy of the sensor. The bending strength is a value measured in accordance with ISO178, and specifically, it can be measured by the method described in the examples described later. For a method of bonding a WGF to a molded body having a curved surface, refer to JP 2022-165579 A. In particular, when a WGF is bonded to a curved surface, a resin substrate having low bending strength may suffer from cracks during a constant temperature and humidity test or a thermal cycle test. Therefore, it is desirable to use a methacrylic resin composition within the preferred range described below.

[0041] -Rockwell hardness- The M-scale Rockwell hardness of the resin window member of this embodiment is preferably 90 or more, more preferably 98 or more, even more preferably 102 or more, and particularly preferably 106 or more. The Rockwell hardness can be increased by increasing the Rockwell hardness of the molded body contained in the resin window member. In a near-infrared sensor, it is desirable for the Rockwell hardness to be as high as possible in order to prevent scratches caused by flying pebbles and the like. On the other hand, resins with high Rockwell hardness tend to have high flexural modulus, and a high flexural modulus is undesirable because it is prone to stress distortion when assembled into a housing, resulting in high photoelasticity and making it difficult to capture clear images. Therefore, a Rockwell hardness of 115 or less is preferable. The Rockwell hardness can be measured by the method described in the Examples below. The Rockwell hardness can be adjusted to the above range by a method of producing a molded article made of a resin composition preferred in the present invention, or by providing a layer of silica particles or a resin that is cured by heat or ultraviolet light on the surface of the molded article.

[0042] <Other materials> [Polarizing element with polarization separation performance for light with wavelengths in the near infrared region] The resin window member of this embodiment can use a near-infrared region compatible polarizing element as the other member. The near-infrared region compatible conversion element is preferably bonded to the molded body. When the near-infrared compatible polarizing element performs polarization separation by absorption / transmission, it absorbs light in the near-infrared region and converts it into heat, and the inside of the near-infrared sensor, the base material to which the polarizing element is bonded, and the adjacent members are exposed to a high-temperature environment, which can cause adverse effects such as dimensional changes, deformation, and performance deterioration. Therefore, it is preferable to use a reflective polarizing element.

[0043] (Reflective polarizing element) As the reflective polarizing element, an element having a polarizing beam splitter (PBS) function, which is a polarizing splitting mirror that splits polarized light, can be used. For example, a polarizing element in which thin films with different birefringence are laminated (hereinafter, sometimes referred to as a laminated reflective polarizing element) or a structural birefringent wire grid polarizing element using a subwavelength structure can be used. As a polarizing element that maintains a polarization separation function even for wavelengths in the near-infrared range, wire grid polarizing elements manufactured by MOXTEK and wire grid reflective polarizing elements (WGF: registered trademark) manufactured by Asahi Kasei Corporation can be used industrially.

[0044] As the reflective polarizing element, a wire grid reflective polarizing element (manufactured by Asahi Kasei Corporation, WGF: registered trademark) is particularly suitable. When used by bonding to one surface of the above-mentioned molded body, it can be bonded not only to flat surfaces but also to curved surfaces. Since it has a function of polarization separation characteristics that does not depend on stretching, the polarization characteristics are unlikely to be destroyed even if tension is applied to the base film due to bonding to a curved surface. In the case of a laminated reflective polarizing element, a process is required in which the element is deformed into a rotationally asymmetric shape using a mold before bonding to a lens, taking into account the difference in shrinkage ratio of two orthogonal axes, before bonding to a substrate having a curved surface. However, in the case of a wire grid film, it is possible to directly bond it to a substrate without such pretreatment. Furthermore, since the reflection surface involved in the polarization separation is one surface, unlike polarization separation by multiple reflection, it has excellent resolution performance when an image is reflected, and therefore can be suitably used in this embodiment.

[0045] The wire grid reflective polarizing element has a structure in which a supporting substrate (described below, for example, a film is used as a base) and metal wires (for example, aluminum) are supported by a large number of resin protrusions arranged on the surface of the supporting substrate at a pitch equal to or smaller than the wavelength of visible light (approximately 100 nm). The wire-grid reflective polarizing element has the property of reflecting light that vibrates parallel to the metal wires and transmitting light that vibrates perpendicular to the wires, allowing the polarization direction of reflection / transmission to be selected by changing the orientation of the metal wires.

[0046] The wire-grid reflective polarizing element will now be described with reference to Fig. 2, which is a cross-sectional view of the wire-grid reflective polarizing element. The wire grid reflective polarizing element includes a supporting substrate (base film) 21 and a resin substrate 22 provided on a surface 21a of the supporting substrate 21 with a bonding layer 29 interposed therebetween. As shown in Fig. 2, a plurality of grid-shaped protrusions 23 are provided on the resin substrate 22. Also, as shown in Fig. 2, the resin substrate 22 has a substrate layer 24 having a predetermined thickness and the grid-shaped protrusions 23 integrally formed therewith.

[0047] The supporting substrate 21 need only be substantially transparent in the desired wavelength region, and may be made of, for example, an inorganic material such as glass or a resin material. However, it is preferable to use a film (resin material) since a roll process can be used as a manufacturing method and the film has high conformability to curved surfaces. Resins that can be used for the holding substrate 21 include amorphous thermoplastic resins such as polymethyl methacrylate resin, polycarbonate resin, polystyrene resin, cycloolefin resin (COP), cross-linked polyethylene resin, polyvinyl chloride resin, polyarylate resin, polyphenylene ether resin, modified polyphenylene ether resin, polyetherimide resin, polyethersulfone resin, polysulfone resin, and polyetherketone resin; crystalline thermoplastic resins such as polyethylene terephthalate (PET) resin, polyethylene naphthalate resin, polyethylene resin, polypropylene resin, polybutylene terephthalate resin, aromatic polyester resin, polyacetal resin, and polyamide resin; and triacetate resin (TAC). Specifically, TD80UL and ZRD60SL manufactured by Fuji Film Corporation and KC6UA manufactured by Konica Minolta, Inc. can be suitably used. The resin substrate 22 may be, for example, the same thermoplastic resin as that of the support substrate 21, or may be an ultraviolet (UV) curable resin or a thermosetting resin such as an acrylic, epoxy, or urethane resin. The substrate may be formed by combining the UV curable resin or the thermosetting resin with the thermoplastic resin or the triacetate resin, or by using them alone. Methods for applying the UV curable resin include a gravure method using a gravure roll, a slot die method, and a knife coating method, as well as an inkjet method and a spray coating method using a potential difference. For curing, a light source that emits UV light or visible light of about 405 nm in consideration of absorption by an added ultraviolet absorbing agent, or a light source that emits an electron beam may be used.

[0048] The uneven structure having the lattice-shaped convex portion 23 formed on the surface of the substrate 22 is preferably rectangular in a cross section perpendicular to the extending direction of the uneven structure. The rectangular shape is composed of repeated concave and convex portions, and includes trapezoidal, rectangular, and square shapes. In addition, the contour of the uneven structure in a cross-sectional view can have a curved portion with a curvature that changes gently like a parabola before and after the inflection point when the contour of the uneven structure is considered as a function, and can also include a shape with a constriction in the convex portion. Depending on the shape of the uneven structure, it becomes easy to form metal wires that are continuous in the vertical direction while being spaced apart from each other by the oblique deposition method described later on the side of the convex portion of the uneven shape on the substrate surface and the bottom of the concave portion. When the metal wires are formed by the oblique deposition method, the metal wires 27 are provided so as to be unevenly distributed on one side of the convex portion 23. Therefore, the period of the uneven structure and the period (pitch P) of the metal wires 27 are approximately the same interval.

[0049] The period of the uneven structure (pitch P between the lattice-shaped convex portions 23) (see FIG. 2) is not particularly limited, but is preferably set to a period that can exhibit polarization separation characteristics. In general, the wire grid reflective polarizing element exhibits better polarization separation characteristics in a wide band as the period of the metal wires 27 becomes smaller. When the metal wires 27 are in contact with air (refractive index 1.0), practically sufficient polarization separation characteristics are exhibited by setting the period of the metal wires 27 to 1 / 3 to 1 / 4 or less of the wavelength of the target light. For this reason, when considering the use of light in the visible light region, it is preferable that the period of the metal wires 27 and the period of the uneven structure of the base material 22 are 150 nm or less, more preferably 130 nm or less, even more preferably 120 nm or less, and most preferably 100 nm or less. There is no particular limit to the lower limit of the period of the metal wires 27 and the period of the uneven structure of the base material 22, but from the viewpoint of ease of manufacture, it is preferably 50 nm or more, more preferably 60 nm or more, and even more preferably 80 nm or more. The shorter the period of the metal wires 27, the easier it is to observe the emission line indicating the direction of the polarization axis, which is preferable.

[0050] In addition, in the wire grid polarizer, it is preferable that the metal wires 27 are provided so as to be unevenly distributed on one side of the lattice-shaped protrusions 23 of the uneven structure. Therefore, the extending direction of the uneven structure and the extending direction of the metal wires 27 are substantially parallel. Furthermore, it is sufficient that the uneven structure and the metal wires 27 extend substantially in a predetermined direction, and it is not necessary that the recesses, protrusions, and metal wires of the uneven structure extend strictly parallel to each other.

[0051] 2, a metal layer (metal wire) 27 is formed on at least a part of the surface of each lattice-shaped protrusion 23 via a dielectric layer 26. The dielectric layer 26 does not have to be formed. In such a case, the metal layer 27 is formed directly on the surface of the lattice-shaped protrusion 23.

[0052] In order to improve the adhesion between the material constituting the resin base material 22 and the metal wire 27, a dielectric layer 26 having high adhesion to both materials can be interposed between them. This improves the adhesion between the resin base material 22 and the metal wire 27, thereby preventing the metal wire 27 from peeling off. The dielectric layer 26 may be substantially transparent in the visible range, and examples of suitable dielectrics include oxides, nitrides, halides, and carbides of silicon (Si) alone or in combination (dielectrics in which other elements, elements, or compounds are mixed with a dielectric alone), and oxides, nitrides, halides, and carbides of metals such as aluminum (Al), chromium (Cr), yttrium (Y), zirconium (Zr), tantalum (Ta), titanium (Ti), barium (Ba), indium (In), tin (Sn), zinc (Zn), magnesium (Mg), calcium (Ca), cerium (Ce), and copper (Cu), alone or in combination. There is no particular limitation on the method for laminating the dielectric material, and for example, physical vapor deposition methods such as vacuum deposition, sputtering, and ion plating can be suitably used.

[0053] The metal constituting the metal layer (metal wire) 27 is preferably one that has a high light reflectance in the visible light region and has a high adhesion to the material constituting the dielectric layer 26. The metal wire 27 can be formed using a conductive material such as aluminum, silver, copper, platinum, gold, or an alloy mainly composed of each of these metals. It is preferable that the metal wire 27 is made of aluminum, silver, or an alloy thereof. From the viewpoint of cost, it is more preferable that the metal wire 27 is made of aluminum or an alloy thereof. In particular, aluminum is preferable because it can reduce absorption loss in the visible region. There is no limitation on the method of manufacturing the metal wire 27. For example, a method of forming the metal wire 27 using mask patterning and dry etching by electron beam lithography or interference exposure method, a method of manufacturing the metal wire 27 by oblique deposition, etc. can be mentioned. From the viewpoint of productivity, the oblique deposition method is preferable.

[0054] The oblique deposition method is a method in which, in a cross section perpendicular to the extending direction of the concave-convex structure (hereinafter abbreviated as "cross-sectional view"), the deposition source is in a direction inclined with respect to the perpendicular direction of the surface of the substrate, and a metal is deposited on the substrate while maintaining a predetermined angle. The preferred range of the deposition angle is determined based on the convex portion of the concave-convex structure and the cross-sectional shape of the metal wire to be produced, and is generally preferably 5 degrees to 45 degrees, more preferably 5 degrees to 35 degrees. Furthermore, it is preferable to gradually decrease or increase the deposition angle while taking into consideration the projection effect of the metal deposited during deposition, in order to control the cross-sectional shape such as the height of the metal wire 27. In addition, when the surface of the holding substrate 22 is curved, deposition may be performed from a direction inclined with respect to the normal direction of the surface of the resin substrate 22. In addition, the shape of the deposition source is not limited as long as it can sufficiently deposit the deposition area, and an intermittent dot shape or a continuous line shape can be selected. When the deposition source is point-like, deposition can be performed from an oblique direction with respect to the extending direction of the uneven structure, and the intervals between the uneven structures appear to be wider, allowing deposition to be performed up to the bottoms of the recesses, which is preferable.

[0055] Specifically, the center of the deposition source is provided in a direction that is 5 degrees or more and less than 45 degrees with respect to the vertical direction at the center of the deposition area on the surface of the resin substrate 22 having a concave-convex structure extending approximately parallel with a predetermined pitch in a specific direction, and the metal wire 27 is formed on the concave-convex structure. More preferably, the center of the deposition source is provided in an angle direction that is 5 degrees or more and less than 35 degrees with respect to the vertical direction at the center of the deposition area on the surface of the resin substrate 22. This makes it possible to selectively provide the metal wire 27 on either side of the convex portion 23 of the concave-convex structure on the surface of the resin substrate 22. When deposition is performed while transporting the substrate, deposition may be performed so that the center of the deposition area and the center of the deposition source at a certain moment satisfy the above-mentioned conditions.

[0056] The amount of metal deposition (average thickness) is preferably about 50 nm to 300 nm. The average thickness here refers to the thickness of the deposition when a substance is deposited on a smooth glass substrate from a direction perpendicular to the glass surface, and is used as a guide for the amount of metal deposition.

[0057] 2, a bonding layer 29 of an adhesive layer or a pressure-sensitive adhesive layer may be interposed between the holding substrate 21 and the resin substrate 22 in order to improve the adhesion between the holding substrate 21 and the resin substrate 22 and adjust the refractive index. For example, a thin dielectric layer of silica, alumina, or the like may be formed between the holding substrate 21 and the resin substrate 22, or a modified layer may be formed by subjecting the surface 21a of the holding substrate 21 to corona discharge treatment, atmospheric pressure plasma treatment, vacuum plasma treatment, or ultraviolet treatment to impart functional groups or a fine uneven shape.

[0058] The thickness of the wire grid polarizer 20 is not particularly limited, but is, for example, about 50 μm to 200 μm. A thinner thickness improves conformability to the molded body, and makes it possible to dramatically improve the yield in the process of bonding to the surface of the molded body. Specifically, the thickness is preferably 50 to 150 μm or less, and more preferably 50 to 130 μm or less. Furthermore, by separating the holding substrate 21 and configuring the wire grid polarizer 20 from the resin substrate 22 and the metal layer 27, the thickness of the wire grid polarizer 20 can be reduced to about 0.5 μm to 50 μm.

[0059] Prior to the adhesive processing, surface treatment such as corona treatment can be performed on the exposed surface of the support substrate 21 of the wire grid polarizer that does not have the metal wires 27, which is effective in improving adhesive strength. When the grid-shaped protrusions 23 are COP, the discharge amount calculated from the discharge electrode length, the substrate film transport speed, and the discharge power is set to 10 to 120 W·min / m in order to prevent the metal wires 27 from detaching from the uneven structure. 2 It is preferable to adjust the processing conditions accordingly.

[0060] [Adhesives and adhesives] As the material used for the adhesion and bonding process for bonding the molded body and the polarizing element, various adhesives and pressure-sensitive adhesives can be used, but from the viewpoint of processability, a solid sheet-like material is preferred, and one example is a pressure-sensitive adhesive.

[0061] In general, when the metal wire 27 on the surface of the grid-shaped convex portion 23 is provided in contact with the adhesive layer, the metal wire 27 may be corroded by the acid component contained in the adhesive layer depending on the type of adhesive used, and the polarization separation characteristics may be reduced. Therefore, particularly when the adhesive layer is attached to the surface of the metal wire 27, it is also possible to use a material that contains as little acid component as possible. By covering the metal wire 27 with a material that contains as little acid component as possible, it is possible to suppress the deterioration of the metal wire 27 due to the adhesion of water droplets in a high-temperature and high-humidity environment, and to suppress the deterioration of the metal wire 27 due to the acid contained in the adhesive layer. As a material that contains as little acid as possible, a material with an acid value of 5.0 mgKOH / g or less can be used. If the acid strength is less than this value, it is possible to suppress the deterioration of the metal wire 27 due to the acid contained in the adhesive layer, which causes the polarization degree of the wire grid polarizer to fluctuate.

[0062] As a specific adhesive, a double-sided tape with both sides covered with release paper can be used. Any material having transparency that can transmit light of the desired wavelength can be used without any problem, and for example, CS9861US, CS9862UA, HJ-9150W manufactured by Nitto Denko, MO-T015, MO-3005, MO-3006, MO-3014 manufactured by Lintec, 5405X-75 manufactured by Sekisui Chemical Co., Ltd., etc. can be suitably used. When attaching a wire grid polarizer in which the holding substrate 21 is a film, it is necessary to consider the expansion and contraction of the film due to changes in environmental temperature. In order to follow the tension applied to the bonding surface that occurs due to the difference in contraction and expansion between the substrate (e.g., lens) and the wire grid polarizer to be bonded, a flexible adhesive material is effective, and an adhesive material made of an acrylic resin or a silicone resin as described above is preferable. When heat resistance is considered, an adhesive mainly composed of a silicone resin (hereinafter referred to as a "silicone adhesive") is preferable. Furthermore, when taking into consideration transparency, adhesive strength, procurement costs, etc., a pressure-sensitive adhesive containing an acrylic resin as a main component (hereinafter referred to as an "acrylic pressure-sensitive adhesive") is preferred, and furthermore, it is more preferable for the resin structure of the pressure-sensitive adhesive to have a hydroxyl group from the viewpoint of preventing deterioration of the polarization properties.

[0063] The thickness of the adhesive material is preferably 50 μm or more from the viewpoint of maintaining ease of handling and flexibility, whereas if the adhesive material is too thick, it becomes difficult to ensure mirror finish (or surface precision according to the design shape), so the thickness is preferably 100 μm or less.

[0064] In addition, it is preferable that the adhesive layer is made of a material with strong adhesive strength. By using a material with strong adhesive strength, peeling can be suppressed even in high temperature and high humidity environments, etc. As a material with strong adhesive strength, a material with adhesive strength to glass of 1.5 N / 25 mm or more may be used, and preferably 5.0 N / 25 mm or more.

[0065] The adhesive may contain additives such as refractive index adjusters, tackifiers, fillers, pigments, diluents, etc., and examples of additives include ultraviolet absorbers, antioxidants, light stabilizers, antistatic agents, etc. that improve the stability of the adhesive.

[0066] The resin window member of the present embodiment may include a member other than the polarizing element. In particular, it is preferable that the resin window member is composed only of the molded body and the near-infrared polarizing element, and may be composed only of the molded body.

[0067] <Resin composition> The molded body included in the resin window member of this embodiment is formed by injection molding. The molded body is composed of a resin composition containing a thermoplastic resin. The resin composition may be only a thermoplastic resin, or may be a mixture further containing other components (for example, additives described later). As the thermoplastic resin, a methacrylic resin is preferable. The molded body contained in the resin window member of this embodiment is not particularly limited as long as it is a resin that combines low birefringence and heat resistance properties without impairing the function of the near-infrared compatible polarizing element that can be used in combination, but it is preferable that the resin be made of a resin composition containing a methacrylic resin as a resin that can achieve highly low birefringence.

[0068] [Methacrylic resin] In order to ensure sufficient heat resistance against heat generation in the high-temperature environment inside a vehicle or in a computing chip that processes images (including video) captured by a camera, it is preferable that the methacrylic resin contained in the molded product of the resin window member of this embodiment contains a methacrylic resin having a structural unit (X) having a ring structure in the main chain and a structural unit derived from a methacrylic acid ester monomer. By containing a methacrylic resin, particularly a methacrylic resin containing a structural unit (X) having a ring structure in the main chain and a methacrylic acid ester monomer unit, it is possible to obtain a resin window member that has high heat resistance, a sufficiently small phase difference in the effective surface of the resin window member, and a sufficiently small photoelastic coefficient.

[0069] (Methacrylic resin with a ring structure in the main chain) Hereinafter, each structural unit of the methacrylic resin having a structural unit (X) having a ring structure in the main chain and a structural unit derived from a methacrylic acid ester monomer will be described.

[0070] -Structural units derived from methacrylate ester monomers- Examples of structural units derived from methacrylic acid ester monomers include structural units derived from monomers selected from the methacrylic acid esters shown below. Examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, cyclooctyl methacrylate, tricyclodecyl methacrylate, dicyclooctyl methacrylate, tricyclododecyl methacrylate, isobornyl methacrylate, phenyl methacrylate, benzyl methacrylate, 1-phenylethyl methacrylate, 2-phenoxyethyl methacrylate, 3-phenylpropyl methacrylate, and 2,4,6-tribromophenyl methacrylate. These monomers may be used alone or in combination of two or more kinds. As the structural unit derived from the methacrylic acid ester monomer, a structural unit derived from methyl methacrylate or benzyl methacrylate is preferable in terms of excellent transparency and weather resistance of the resulting methacrylic resin. The structural unit derived from the methacrylic acid ester monomer may be contained in only one type, or in two or more types.

[0071] By appropriately adjusting the ratio of the structural unit (X) having a ring structure in the main chain and the structural unit derived from the methacrylic acid ester monomer as the methacrylic resin constituting the molded body contained in the resin window member of this embodiment, it is possible to reduce the birefringence caused by the orientation during molding or residual stress, and obtain a resin window member for a near-infrared sensor having an average absolute value of the retardation at a wavelength of 850n in the effective plane of 20 nm or less. In addition, by appropriately adjusting the above ratio, it is possible to impart sufficient heat resistance to the methacrylic resin. From these viewpoints, the content of the structural unit derived from the methacrylic acid ester monomer is preferably 50 to 97 mass%, more preferably 55 to 97 mass%, even more preferably 55 to 95 mass%, even more preferably 60 to 93 mass%, and particularly preferably 60 to 90 mass%, based on 100 mass% of the methacrylic resin. The content of structural units derived from methacrylic acid ester monomers is 1 H-NMR measurement and 13 It can be determined by C-NMR measurement. 1 H-NMR measurement and 13 For example, C-NMR measurements are performed using CDCl as the measurement solvent. 3 Alternatively, DMSO-d6 can be used and the measurement can be performed at a temperature of 40°C.

[0072] -Structural unit (X) having a ring structure in the main chain- The structural unit (X) having a ring structure in the main chain will be described below. The structural unit (X) having a ring structure in the main chain preferably contains at least one structural unit selected from the group consisting of structural units derived from N-substituted maleimide monomers, glutarimide structural units, and lactone ring structural units, and more preferably consists of at least one structural unit selected from the group consisting of structural units derived from N-substituted maleimide monomers, glutarimide structural units, and lactone ring structural units. The structural unit (X) having a ring structure in the main chain may be one type or a combination of multiple types.

[0073] Generally, the absolute value of the in-plane retardation decreases as the wavelength increases, but it is also possible to design the absolute value of the retardation to increase as the wavelength increases by controlling the amount of structural unit (X) having a ring structure in the main chain. Such material design is a concept used in wave plates, λ / 4 elements, etc. In the present invention, it is desired that the absolute value of the in-plane retardation in the near-infrared region is small, so when designing a material, the wavelength dispersion of the absolute value of the retardation does not matter, but it is necessary to design the resin composition so that the absolute value of the in-plane retardation at wavelengths of 850 nm or more used in near-infrared cameras is small.

[0074] --Structural units derived from N-substituted maleimide monomers-- Next, the structural unit derived from the N-substituted maleimide monomer will be described. The structural unit derived from the N-substituted maleimide monomer may be at least one structural unit selected from the group consisting of a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), and is preferably formed from both of the structural units represented by the following formula (1) and the following formula (2).

[0075] [ka] In formula (1), R 1 represents an arylalkyl group having 7 to 14 carbon atoms or an aryl group having 6 to 14 carbon atoms; R 2 and R 3 each independently represents a hydrogen atom, an oxygen atom, a sulfur atom, an alkyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 14 carbon atoms. Also, R 2 or R 3 When is an aryl group, R 2 or R 3 may contain a halogen atom as a substituent. Also, R 1 may be substituted with a substituent such as a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, or a benzyl group. [ka] In formula (2), R 4 represents a hydrogen atom, a cycloalkyl group having 3 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms; R 5 and R 6 each independently represents a hydrogen atom, an oxygen atom, a sulfur atom, an alkyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 14 carbon atoms.

[0076] Specific examples are given below. Examples of monomers (N-arylmaleimides, N-aromatic substituted maleimides, etc.) that form the structural unit represented by formula (1) include N-phenylmaleimide, N-benzylmaleimide, N-(2-chlorophenyl)maleimide, N-(4-chlorophenyl)maleimide, N-(4-bromophenyl)maleimide, N-(2-methylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-(2-ethylphenyl)maleimide, N-(2-methoxyphenyl)maleimide, N-(2-nitrophenyl)maleimide, N-phenyl ... N-(2,4,6-trimethylphenyl)maleimide, N-(4-benzylphenyl)maleimide, N-(2,4,6-tribromophenyl)maleimide, N-naphthylmaleimide, N-anthracenylmaleimide, 3-methyl-1-phenyl-1H-pyrrole-2,5-dione, 3,4-dimethyl-1-phenyl-1H-pyrrole-2,5-dione, 1,3-diphenyl-1H-pyrrole-2,5-dione, 1,3,4-triphenyl-1H-pyrrole-2,5-dione, and the like. Among these monomers, N-phenylmaleimide and N-benzylmaleimide are preferred because the resulting methacrylic resin has excellent heat resistance and optical properties such as birefringence. These monomers may be used alone or in combination of two or more kinds.

[0077] Examples of the monomer that forms the structural unit represented by formula (2) include N-methylmaleimide, N-ethylmaleimide, Nn-propylmaleimide, N-isopropylmaleimide, Nn-butylmaleimide, N-isobutylmaleimide, Ns-butylmaleimide, Nt-butylmaleimide, Nn-pentylmaleimide, Nn-hexylmaleimide, Nn-heptylmaleimide, Nn-octylmaleimide, and N- Examples of the maleimide include laurylmaleimide, N-cyclopentylmaleimide, N-cyclohexylmaleimide, 1-cyclohexyl-3-methyl-1H-pyrrole-2,5-dione, 1-cyclohexyl-3,4-dimethyl-1H-pyrrole-2,5-dione, 1-cyclohexyl-3-phenyl-1H-pyrrole-2,5-dione, and 1-cyclohexyl-3,4-diphenyl-1H-pyrrole-2,5-dione. Among these monomers, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, and N-cyclohexylmaleimide are preferred because they provide methacrylic resins with excellent weather resistance, and N-cyclohexylmaleimide having an alicyclic group in the side chain is particularly preferred because it has excellent low moisture absorption, which is a requirement for optical materials in recent years. These monomers can be used alone or in combination of two or more.

[0078] In the above methacrylic resin, it is particularly preferable to use a structural unit represented by formula (1) in combination with a structural unit represented by formula (2) in order to develop highly controlled birefringence characteristics. The molar ratio (X1 / X2) of the content (X1) of the structural unit represented by formula (1) to the content (X2) of the structural unit represented by formula (2) is preferably more than 0 and 15 or less, more preferably more than 0 and 10 or less. When the molar ratio (X1 / X2) is within this range, the resin window member of this embodiment maintains its transparency, does not turn yellow, and does not lose its environmental resistance, and can exhibit good heat resistance and good photoelastic properties.

[0079] The content of the structural unit derived from the N-substituted maleimide monomer is preferably in the range of 5 to 40% by mass, and more preferably in the range of 5 to 35% by mass, based on 100% by mass of the methacrylic resin. Within this range, the methacrylic resin can obtain a more sufficient improvement in heat resistance, and can obtain more preferable improvements in weather resistance, low water absorption, and optical properties. In addition, keeping the content of structural units derived from N-substituted maleimide monomers to 40 mass% or less is effective in preventing a decrease in the physical properties of the methacrylic resin due to a decrease in the reactivity of the monomer component during the polymerization reaction and an increase in the amount of unreacted remaining monomer. In addition, by appropriately adjusting the content of the structural units derived from the N-substituted maleimide monomer within this range, it is possible to reduce birefringence caused by orientation during molding or residual stress, and obtain a resin window member for near-infrared sensors having an average absolute value of retardation within the effective plane of 20 nm or less. The optimal content of the structural units derived from the N-substituted maleimide monomer varies depending on the type of N-substituted maleimide, but for example, when methyl methacrylate is used as the methacrylic acid ester monomer and N-phenylmaleimide and N-cyclohexylmaleimide are used as the N-substituted maleimide monomers, it is preferable to adjust the content within the ranges of 79 to 83 mass% of the structural units derived from methyl methacrylate, 6 to 8 mass% of the structural units derived from N-phenylmaleimide, and 11 to 13 mass% of the structural units derived from N-cyclohexylmaleimide. On the other hand, when emphasis is placed on increasing heat resistance and Rockwell hardness, it is preferable to increase the content of structural units derived from N-substituted maleimide monomers, and in particular, it is possible to improve both properties by adjusting the content of N-phenylmaleimide to the range of 5 to 40% by mass, more preferably 7 to 37% by mass, and even more preferably 10 to 34% by mass.

[0080] In the manufacturing process of N-substituted maleimide, acid components such as maleic acid and fumaric acid remain as by-products, but the amount of the acid components can be sufficiently reduced in the purification process. In addition, the ring is opened by hydrolysis during storage, just as in a high-temperature and high-humidity environment, and acid components such as maleic acid and fumaric acid are generated as by-products, but the generation of these acid components can be suppressed by storing in a low-temperature, dark place under humidity control. In addition, in the case of methacrylic resins having N-substituted maleimide in the main chain, there is an advantage that the amount of remaining acid components and alkali components is easily controlled without going through a cyclization process using an acid or base. As a result, a resin with a controlled acid content can be obtained.

[0081] The methacrylic resin having structural units derived from N-substituted maleimide monomers, which is an example of a methacrylic resin constituting the molded body contained in the resin window member of this embodiment, may contain structural units derived from other monomers copolymerizable with the methacrylic acid ester monomer and the N-substituted maleimide monomer, as long as the object of the present invention is not impaired. For example, the other copolymerizable monomers include aromatic vinyls; unsaturated nitriles; acrylic esters having a cyclohexyl group, a benzyl group, or an alkyl group having 1 to 18 carbon atoms; glycidyl compounds; and unsaturated carboxylic acids. Examples of the aromatic vinyl include styrene, α-methylstyrene, and divinylbenzene. Examples of the unsaturated nitrile include acrylonitrile, methacrylonitrile, and ethacrylonitrile. Examples of the acrylic ester include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, and butyl acrylate. The glycidyl compound includes glycidyl (meth)acrylate and the like. The unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and half-esters or anhydrides thereof. The structural unit derived from the other copolymerizable monomer may be of only one type, or may be of two or more types.

[0082] The content of structural units derived from these other copolymerizable monomers is preferably 0 to 10 mass%, more preferably 0 to 9 mass%, and even more preferably 0 to 8 mass%, based on 100 mass% of the methacrylic resin. It is preferable for the content of structural units derived from other monomers to be within this range, since this makes it possible to improve the molding processability and mechanical properties of the resin without impairing the inherent effect of introducing a ring structure into the main chain.

[0083] The content of the structural unit derived from the N-substituted maleimide monomer and the content of the structural unit derived from other copolymerizable monomers are as follows: 1 H-NMR measurement and 13 It can be determined by C-NMR measurement. 1 H-NMR measurement and 13 For example, C-NMR measurements are performed using CDCl as the measurement solvent. 3 Alternatively, DMSO-d6 can be used and the measurement can be performed at a temperature of 40°C.

[0084] --Glutarimide structural unit-- Examples of methacrylic resins having glutarimide structural units in the main chain include methacrylic resins having glutarimide structural units described in JP-A-2006-249202, JP-A-2007-009182, JP-A-2007-009191, JP-A-2011-186482, and Republished Patent Publication No. 2012 / 114718, and can be formed by the methods described in these publications. The glutarimide structural unit constituting the methacrylic resin may be formed after polymerization of the resin. Specifically, the glutarimide structural unit may be represented by the following general formula (3).

[0085] [ka] In the above general formula (3), preferably R 7 and R 8 are each independently a hydrogen atom or a methyl group, R 9 is any one of a hydrogen atom, a methyl group, a butyl group, and a cyclohexyl group, and more preferably, R 7 is a methyl group, and R 8 is a hydrogen atom, and R 9 is a methyl group. The glutarimide-based structural unit may include only one type, or may include a plurality of types.

[0086] In the methacrylic resin having a glutarimide structural unit, the content of the glutarimide structural unit is preferably in the range of 3 to 70 mass %, more preferably in the range of 3 to 60 mass %, based on 100 mass % of the methacrylic resin. It is preferable that the content of the glutarimide structural unit is within the above range, since a resin having good moldability, heat resistance, and optical properties can be obtained. In addition, by appropriately adjusting the content of the glutarimide structural unit within this range, it is possible to reduce birefringence caused by orientation during molding or residual stress, and obtain a resin window member for near-infrared sensors having an average absolute value of retardation within the effective surface of 20 nm or less. 7 ~R 9 The optimum content of glutarimide structural units varies depending on the type of the substituent of R. 7 and R 8 is a hydrogen atom, R 9 When the content of the glutarimide structural unit is in the range of 3 to 10 mass % in the case where the group is a methyl group, birefringence caused by orientation or residual stress during molding can be reduced, and a resin window member for near-infrared sensors having an average absolute value of retardation within the effective surface of 20 nm or less can be obtained. The content of glutarimide structural units in the methacrylic resin can be determined by the method described in the above-mentioned patent document.

[0087] The methacrylic resin having a glutarimide structural unit may further contain an aromatic vinyl monomer unit, if necessary. The aromatic vinyl monomer is not particularly limited, but examples thereof include styrene and α-methylstyrene, with styrene being preferred.

[0088] The content of aromatic vinyl units in the methacrylic resin having glutarimide structural units is not particularly limited, but is preferably 0 to 20% by mass, with the methacrylic resin having glutarimide structural units being 100% by mass. When the content of the aromatic vinyl unit is within the above range, it is possible to achieve both heat resistance and excellent photoelasticity, which is preferable. For example, when a resin is obtained by glutarimidating a methyl methacrylate-styrene copolymer obtained by copolymerizing methyl methacrylate as the methacrylic acid ester monomer and styrene as the aromatic vinyl monomer, by adjusting the ranges of 25 to 90 mass% of structural units derived from methyl methacrylate, 5 to 15 mass% of structural units derived from styrene, and 5 to 70 mass% of glutarimide-based structural units, it is possible to reduce birefringence caused by orientation and residual stress during molding and to obtain a resin window component for near-infrared sensors with an average absolute value of retardation within the effective surface of 20 nm or less. As another effect, by copolymerizing a monomer having low water absorption such as styrene, it is possible to reduce the water absorption rate of the resulting methacrylic resin and a resin composition of the resin, thereby making it possible to suppress deterioration of surface accuracy after reliability testing in a high-humidity environment.

[0089] -Lactone ring structural unit- Methacrylic resins having a lactone ring structural unit in the main chain can be formed by the methods described in, for example, JP-A Nos. 2001-151814, 2004-168882, 2005-146084, 2006-96960, 2006-171464, 2007-63541, 2007-297620, and 2010-180305.

[0090] The lactone ring structural unit constituting the methacrylic resin may be formed after polymerization of the resin. The lactone ring structural unit is preferably a six-membered ring because this provides excellent stability of the ring structure. As the 6-membered lactone ring structural unit, for example, a structure represented by the following general formula (4) is particularly preferred.

[0091] [ka] In the above general formula (4), R 10 , R 11 and R 12 are each independently a hydrogen atom or an organic residue having 1 to 20 carbon atoms. Examples of the organic residue include saturated aliphatic hydrocarbon groups (alkyl groups, etc.) having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, a propyl group, etc.; unsaturated aliphatic hydrocarbon groups (alkenyl groups, etc.) having 2 to 20 carbon atoms, such as an ethenyl group, a propenyl group, etc.; aromatic hydrocarbon groups (aryl groups, etc.) having 6 to 20 carbon atoms, such as a phenyl group, a naphthyl group, etc.; and groups in which one or more hydrogen atoms in these saturated aliphatic hydrocarbon groups, unsaturated aliphatic hydrocarbon groups, and aromatic hydrocarbon groups have been substituted with at least one group selected from the group consisting of a hydroxy group, a carboxyl group, an ether group, and an ester group.

[0092] The lactone ring structural unit can be formed, for example, by copolymerizing an acrylic acid monomer having a hydroxy group with a methacrylic acid ester monomer such as methyl methacrylate to introduce a hydroxy group and an ester group or a carboxyl group into the molecular chain, and then causing dealcoholization (esterification) or dehydration condensation (hereinafter also referred to as a "cyclization condensation reaction") between the hydroxy group and the ester group or the carboxyl group.

[0093] Examples of the acrylic acid monomer having a hydroxy group used in the polymerization include 2-(hydroxymethyl)acrylic acid, 2-(hydroxyethyl)acrylic acid, 2-(hydroxymethyl)alkyl acrylates (e.g., methyl 2-(hydroxymethyl)acrylate, ethyl 2-(hydroxymethyl)acrylate, isopropyl 2-(hydroxymethyl)acrylate, n-butyl 2-(hydroxymethyl)acrylate, t-butyl 2-(hydroxymethyl)acrylate), and 2-(hydroxyethyl)alkyl acrylates. Preferred are 2-(hydroxymethyl)acrylic acid and 2-(hydroxymethyl)alkyl acrylates, which are monomers having a hydroxyalkyl moiety, and particularly preferred are methyl 2-(hydroxymethyl)acrylate and ethyl 2-(hydroxymethyl)acrylate.

[0094] The content of the lactone ring structural unit in the methacrylic resin having the lactone ring structural unit in the main chain is preferably 5 to 40 mass %, and more preferably 5 to 35 mass %, relative to 100 mass % of the methacrylic resin. When the content of the lactone ring structural unit is within this range, the effects of introducing a ring structure, such as improved solvent resistance and improved surface hardness, can be achieved while maintaining moldability. Furthermore, by appropriately adjusting the content of the lactone ring structural unit within this range, it is possible to reduce birefringence caused by orientation during molding and residual stress, and to obtain a resin window member for a near-infrared sensor having an average absolute value of retardation within the effective surface of 20 nm or less. The content of the lactone ring structure in the methacrylic resin can be determined by the method described in the above-mentioned patent document.

[0095] The methacrylic resin having a lactone ring structural unit in the main chain may have a structural unit derived from another monomer copolymerizable with the above-mentioned methacrylic acid ester monomer and the acrylic acid monomer having a hydroxy group. Examples of such other copolymerizable monomers include monomers having a polymerizable double bond, such as styrene, vinyl toluene, α-methyl styrene, α-hydroxymethyl styrene, α-hydroxyethyl styrene, acrylonitrile, methacrylonitrile, methallyl alcohol, ethylene, propylene, 4-methyl-1-pentene, vinyl acetate, 2-hydroxymethyl-1-butene, methyl vinyl ketone, N-vinylpyrrolidone, and N-vinyl carbazole. The copolymer may contain only one type of these other monomers (structural units), or may contain two or more types. In particular, by copolymerizing a monomer with low water absorption such as styrene, it is possible to reduce the water absorption rate of the resulting methacrylic resin and a resin composition of the resin, which makes it possible to prevent peeling of the reflective polarizing element after reliability testing in a high-humidity environment and to suppress deterioration of the lens surface precision.

[0096] The content of structural units derived from these other copolymerizable monomers is preferably 0 to 20 mass% relative to 100 mass% of the methacrylic resin, and from the viewpoint of weather resistance, it is more preferably less than 10 mass%, and even more preferably less than 7 mass%. The methacrylic resin may have only one type of structural unit derived from the other copolymerizable monomer, or may have two or more types.

[0097] -Method for producing methacrylic resin containing hydrogenated aromatic ring structural unit- As a method for obtaining a methacrylic resin having low birefringence characteristics other than a method for obtaining a methacrylic resin having a structural unit having a ring structure in the main chain and a structural unit derived from a methacrylic acid ester monomer, an example is a methacrylic resin having an aromatic ring hydrogenated structural unit.

[0098] As a method for producing a methacrylic resin having a hydrogenated aromatic ring structural unit, a method is used in which a copolymer of an aromatic vinyl compound and a (meth)acrylate is hydrogenated in the presence of a hydrogenation catalyst and a reaction solvent to produce a nuclear-hydrogenated polymer. The method of polymerizing the aromatic vinyl compound and the monomer containing (meth)acrylate can be a known method, but the radical polymerization method is industrially convenient. The radical polymerization can be appropriately selected from known methods such as bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization, but it is preferable to manufacture by bulk polymerization or solution polymerization in order to avoid the inclusion of moisture during the hydrogenation reaction. In the above-mentioned manufacturing method, the polymerization form can be, for example, any of the batch polymerization method, semi-batch method, and continuous polymerization method. Methacrylic resins containing hydrogenated aromatic ring structural units can be formed, for example, by the methods described in JP-A-2006-291184, JP-A-2006-291184, JP-A-2014-77043, JP-A-2014-77044, and the like.

[0099] Hereinafter, an example of a method for producing a methacrylic resin containing a hydrogenated aromatic ring structural unit obtained by hydrogenating a copolymer of an aromatic vinyl compound and a (meth)acrylate will be specifically described.

[0100] Specific examples of aromatic vinyl compounds used in polymerization include styrene, α-methylstyrene, vinyltoluene, α-hydroxymethylstyrene, α-hydroxyethylstyrene, p-hydroxystyrene, alkoxystyrene, and chlorostyrene, with styrene being preferred. It is also possible to copolymerize two or more aromatic vinyl compounds. In particular, it is preferred to use styrene having a substituent at the α-position, since this can increase the heat resistance of the resin.

[0101] In the case of a copolymer of an aromatic vinyl compound and a (meth)acrylate, the composition of the structural unit of the copolymer does not necessarily match the composition of the charged monomer, but is determined by the amount of monomer actually incorporated into the copolymer by the polymerization reaction. The ratio of the structural units of the copolymer matches the charged monomer composition ratio if the polymerization rate is 100%, but in reality, it is often produced with a polymerization rate of 50 to 80%, and since the more reactive the monomer, the easier it is to be incorporated into the copolymer, there is a discrepancy between the charged monomer composition and the composition of the structural unit of the copolymer, so it is necessary to appropriately adjust the composition ratio of the charged monomer.

[0102] In the structural units of the copolymer of aromatic vinyl compound and (meth)acrylate used in the hydrogenation reaction, the molar ratio (A / B) of structural units (A moles) derived from (meth)acrylate monomer to structural units (B moles) of aromatic vinyl compound monomer is 0.25 or more and 4.0 or less. If it is less than 0.25, the mechanical strength is inferior and it may not be practical. If it exceeds 4.0, the aromatic rings to be hydrogenated are few, so the performance improvement effect by the hydrogenation reaction, such as improvement of the glass transition temperature, may be insufficient.

[0103] The content of structural units derived from these other copolymerizable monomers is preferably 0 to 20 mass% relative to 100 mass% of the methacrylic resin, and from the viewpoint of weather resistance, it is more preferably less than 10 mass%, and even more preferably less than 7 mass%. The methacrylic resin may have only one type of structural unit derived from the other copolymerizable monomer, or may have two or more types.

[0104] The methacrylic resin preferably has at least one structural unit selected from the group consisting of a structural unit derived from an N-substituted maleimide monomer, a glutarimide structural unit, a lactone ring structural unit, and a hydrogenated aromatic ring structural unit. In the case of methacrylic resins that undergo a cyclization process to introduce a ring structure into the main chain, there is a possibility that carboxylic acid side chains remain, which causes the water absorption rate to become very high and adversely affects the adhesion of anti-reflection coatings and mirror coatings and the adhesion of lamination with reflective polarizing elements, so methacrylic resins having structural units derived from N-substituted maleimide monomers and aromatic ring hydrogenated structural units are more preferable. In particular, it is particularly preferable to have structural units derived from N-substituted maleimide monomers, since it is easy to highly control optical properties such as the photoelastic coefficient without blending with other thermoplastic resins. Furthermore, when a near-infrared compatible polarizing element to be used in combination is laminated to one surface of the molded article, it is particularly preferable that the molded article has an N-substituted maleimide monomer unit structure, in that a ring structure is obtained that can improve heat resistance and control low birefringence without going through a cyclization process of adding an acid or base that can cause inhibition of lamination adhesion, etc.

[0105] -Methacrylic resin manufacturing method- The method for producing the above methacrylic resin will be described below.

[0106] --Method for producing methacrylic resin containing structural units derived from N-substituted maleimide monomer-- Methods for producing a methacrylic resin having structural units derived from an N-substituted maleimide monomer in its main chain (hereinafter sometimes referred to as a "maleimide copolymer") include any of the following polymerization methods: bulk polymerization, solution polymerization, suspension polymerization, precipitation polymerization, and emulsion polymerization. From the viewpoint of reducing the amount of residual monomer and impurities contained in the resin window component, preferred are suspension polymerization, bulk polymerization, and solution polymerization, and more preferred is solution polymerization.

[0107] The method of adding the polymerization initiator is not particularly limited as long as it is not a constant addition rate but a variable addition rate according to the monomer concentration remaining in the polymerization solution, and may be added continuously or intermittently. When the polymerization initiator is added intermittently, the amount added per unit time is not considered for the time when the polymerization initiator is not added.

[0108] In the above-mentioned production method, a batch system, a semi-batch system, or a continuous system can be used as a polymerization system. Here, the batch system is a process in which the reaction is started and proceeded after the entire amount of raw materials is charged into a reactor, and the product is recovered after the reaction is completed. The semi-batch system is a process in which either the raw materials are charged or the product is recovered simultaneously during the reaction. Furthermore, the continuous system is a process in which both the raw materials are charged and the product is recovered simultaneously during the reaction. In the above-mentioned production method, it is preferable to use a so-called semi-batch polymerization method in which a part of the monomer is charged into a reactor before the start of polymerization, a polymerization initiator is added to start the polymerization, and then the remaining part of the monomer is supplied, from the viewpoint of precisely controlling the copolymer composition, reducing the amount of remaining N-substituted maleimide at the end of polymerization, and reducing by-products that deteriorate transmittance and haze. The continuous method is not preferred as the above-mentioned production method for the following reasons. When the polymerization reaction is carried out in one complete mixing reactor, there is an advantage that the difference in monomer composition between the fractions having different molecular weights in the methacrylic resin can be reduced, but since a large amount of unreacted monomer remains after polymerization, it tends to have a negative effect on the color tone. On the other hand, when a plug flow reactor is used, the amount of unreacted monomer can be reduced, but the difference in monomer composition between the fractions having different molecular weights in the methacrylic resin tends to be large. When multiple complete mixing reactors or a complete mixing reactor and a plug flow reactor are combined in series, the amount of unreacted monomer can be reduced, but the difference in monomer composition between the fractions tends to be large.

[0109] As a method for controlling impurities in the N-substituted maleimide, a pretreatment step of washing the N-substituted maleimide with water (water washing step) and / or dehydrating the N-substituted maleimide with water (dehydration step) can be provided. The pretreatment step may be only washing with water, or a combination of washing with water and dehydration. In addition, washing with water and dehydration may be performed once each, or multiple times. The pretreatment step may further include a concentration adjustment step for adjusting the concentration of the N-substituted maleimide solution obtained in the dehydration step.

[0110] In the water-washing step, for example, a method can be employed in which the N-substituted maleimide is dissolved in a water-insoluble organic solvent, separated into an organic layer and an aqueous layer, the organic layer is mixed and washed with one or more liquids selected from an acidic aqueous solution, water and an alkaline aqueous solution by a batch system, a continuous system, or both systems, and then the organic layer and the aqueous layer are separated.

[0111] Specific examples of the non-water-soluble organic solvent that can be used include aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as normal hexane and cyclohexane; and halogenated hydrocarbons such as chloroform and dichloroethane. The water used may be sewage water, pure water, or clean water. The acidity of the acidic aqueous solution or the alkaline aqueous solution is not particularly limited.

[0112] The concentration of the N-substituted maleimide in the organic layer before the water washing step is preferably from 0.5 to 30% by mass, more preferably from 10 to 25% by mass, and further preferably from 20 to 25% by mass. The temperature at which the organic layer and the aqueous layer are mixed and washed may be 40°C or higher, preferably 40°C or higher and 80°C or lower, and more preferably 50°C or higher and 60°C or lower. The mass ratio of the aqueous layer to the organic layer is preferably 5% by mass or more and 300% by mass or less, more preferably 10% by mass or more and 200% by mass or less, and even more preferably 30% by mass or more and 100% by mass or less, assuming that the mass of the organic layer is 100% by mass. When the concentration of the N-substituted maleimide in the organic layer, the liquid temperature during washing, and the mass ratio of the aqueous layer are within the above-mentioned ranges, the reaction between the N-substituted maleimide and water does not easily proceed, production of acidic substances can be suppressed, and impurities such as 2-amino-N-substituted succinimide, which is a cause of production of by-products that deteriorate the transmittance and haze, are easily extracted into the aqueous layer, which is preferable.

[0113] When washing in a batch system, the reaction vessel used may be made of stainless steel or glass-lined, or other reaction vessels may be used. The shape of the stirring blade is not particularly limited. Specific stirring blades that can be used include, for example, three-blade swept-back blades, four-blade paddle blades, four-blade inclined paddle blades, six-blade turbine blades, and anchor blades. In addition, Twin Star and Full Zone manufactured by Kobe Steel Eco-Solutions can be used. The stirring time is preferably 10 minutes or more and 120 minutes or less, more preferably 30 minutes or more and 60 minutes or less. The stirring speed is appropriately selected so that the mixture becomes turbulent and does not emulsify. When the stirring time and stirring speed are within these ranges, the stirring efficiency and the extraction efficiency of impurities such as 2-amino-N-substituted succinimide into the aqueous layer are improved, and impurities in the N-substituted maleimide can be further reduced, which is preferable.

[0114] When washing is carried out in a continuous manner, an empty tower, a packed tower, or a plate tower can be used, and a stationary mixer such as a static mixer or a rotary mixer such as a dynamic mixer can also be used. The contact time between the organic layer and the aqueous layer is preferably set to 1 second to 60 minutes, more preferably 30 seconds to 10 minutes. When the contact time is within this range, the reaction between the N-substituted maleimide and water does not easily proceed, acidic substances are not easily generated, and impurities such as 2-amino-N-substituted succinimide, which is one of the factors that cause the generation of by-products that deteriorate the transmittance and haze, are easily extracted into the aqueous layer, which is preferable.

[0115] In the dehydration step, the organic layer is placed in a reaction vessel and heated under reduced pressure to remove water. There are no particular limitations on the pressure and temperature as long as the solvent and water used form an azeotropic composition. The water content in the organic layer after the dehydration step is preferably 100 ppm by mass or less, assuming that the mass of the organic layer is 100% by mass. If the water content after the dehydration step is in this range, it is possible to suppress color deterioration due to water during polymerization of the methacrylic resin, and also to reduce the amount of solvent distilled off together with water, which is preferable from the viewpoint of cost. The organic layer containing the N-substituted maleimide obtained in the dehydration step may be used in the polymerization step as an N-substituted maleimide solution, or an N-substituted maleimide solution whose concentration has been adjusted in the concentration adjustment step may be used in the polymerization step.

[0116] In the concentration adjustment step, for example, the organic layer of the N-substituted maleimide obtained in the dehydration step or the like may be diluted with the water-insoluble organic solvent. The water-insoluble organic solvent used in the concentration adjustment step is preferably the same as the water-insoluble organic solvent used in the water-washing step.

[0117] The N-substituted maleimide solution obtained in the pretreatment step is preferably a solution in the water-insoluble organic solvent (organic layer). The water content in the N-substituted maleimide solution obtained in the above pretreatment step is preferably 200 ppm by mass or less, and more preferably 100 to 200 ppm by mass, relative to 100% by mass of the N-substituted maleimide solution. The mass ratio of the N-substituted maleimide contained in the N-substituted maleimide solution obtained in the above pretreatment step is preferably 5 to 30 mass %, more preferably 5 to 25 mass %, relative to 100 mass % of the N-substituted maleimide solution. When it is within this range, the N-substituted maleimide is less likely to precipitate and can be transported as a homogeneous solution, which is preferable.

[0118] When a plurality of types of N-substituted maleimide solutions are used in the polymerization step, it is preferable that a mixture of the plurality of types of N-substituted maleimide solutions satisfies the above-mentioned water content and / or mass ratio of the N-substituted maleimide, and it is more preferable that each N-substituted maleimide solution satisfies the above-mentioned water content and / or mass ratio of the N-substituted maleimide. By employing the above-mentioned water-washing step and dehydration step of the N-substituted maleimide, it is possible to remove moisture that leads to the generation of acidic substances, and thus it is possible to obtain a methacrylic resin or a composition of said resin having a good color tone even in a thick-walled molded article, which is preferable. In the polymerization step, the N-substituted maleimide solution obtained in the pretreatment step may be mixed with a methacrylic acid ester monomer, any other monomer, a polymerization initiator, a polymerization solvent, a chain transfer agent, etc. to prepare a monomer mixture liquid, which may then be used in the polymerization.

[0119] In order to maintain good transmittance and haze of a molded article obtained using a methacrylic resin or a composition of the resin and to reduce the content of a fluorescent substance, the total mass of unreacted N-substituted maleimide remaining after completion of polymerization is preferably 1,000 ppm by mass or less, more preferably 10 ppm by mass or more and 500 ppm by mass or less, relative to 100% by mass of the polymerization solution at the time of completion of polymerization. Furthermore, when an N-arylmaleimide such as N-phenylmaleimide is used as the N-substituted maleimide, the total mass of unreacted N-arylmaleimides remaining after the completion of polymerization is preferably 500 ppm by mass or less, more preferably 10 ppm by mass or more and 500 ppm by mass or less, and even more preferably 10 ppm by mass or more and 50 ppm by mass or less, relative to 100% by mass of the polymerization solution at the time of the completion of polymerization. When the content is within these ranges, it is preferable because the content of the fluorescent substance in the methacrylic resin and the resulting molded product can be suppressed. In addition, in order to make the amount of unreacted N-substituted maleimide less than 10 mass ppm, it is necessary to increase the polymerization temperature or the amount of polymerization initiator, which is not preferable because it increases the amount of maleimide thermally denatured products and active radicals, which causes the color tone of the methacrylic resin to deteriorate. As a means for controlling the amount of unreacted N-substituted maleimide after the end of polymerization to the above range, a semi-batch polymerization method can be mentioned. In the semi-batch polymerization method, it is preferable to additionally add 5 to 35 mass% of methacrylic acid ester monomer, with the total mass of all monomers (e.g., methacrylic acid ester, N-substituted maleimide, and any other monomer) provided for polymerization being 100 mass% after 30 minutes from the start of addition of the polymerization initiator in the polymerization step. In other words, it is preferable to charge 65 to 95% by mass of the total mass of all monomers provided for polymerization (100% by mass) into the reactor before adding the polymerization initiator, and then additionally add the remaining 5 to 35% by mass of the methacrylic acid ester monomer 30 minutes or more after the start of the addition of the polymerization initiator. The amount of the additionally added methacrylic acid ester monomer is more preferably 10 to 30% by mass, based on the total mass of all monomers provided for polymerization (100% by mass). If the amount of the additionally added methacrylic acid ester monomer is within the above range, the unreacted N-substituted maleimide reacts with the additionally added methacrylic acid ester monomer, and the amount of unreacted N-substituted maleimide after the completion of polymerization can be controlled within the above range, which is preferable.

[0120] The start time of additional addition of the monomer, the speed of additional addition, etc. may be appropriately selected depending on the polymerization conversion rate. Furthermore, in addition to the methacrylic acid ester monomer, a monomer mixture containing an N-substituted maleimide monomer and other monomers may be additionally added within a range that does not impair the effects of the present invention or the reduction of the amount of unreacted N-substituted maleimide. By employing the semi-batch polymerization method as described above, it is possible to reduce the amount of unreacted N-substituted maleimide monomer at the latter stage of polymerization and minimize the production of fluorescent substances in the devolatilization step, and it is therefore preferable to obtain a methacrylic resin and a composition of said resin having good color tone even in lenses with long optical paths.

[0121] Hereinafter, as an example of a method for producing a methacrylic resin having a structural unit derived from an N-substituted maleimide monomer, a case where the resin is produced by semi-batch radical polymerization using a solution polymerization method will be specifically described.

[0122] In the semi-batch polymerization method, it is preferable to additionally add 5 to 35% by mass of the methacrylic acid ester monomer, based on the total mass of all monomers (methacrylic acid ester, N-substituted maleimide, and any other monomers) to be polymerized, 30 minutes or more after the start of the addition of the polymerization initiator. In other words, it is preferable to charge 65 to 95% by mass of the total mass of all monomers to be polymerized, 100% by mass, into the reactor before the start of polymerization, and then additionally add the remaining 5 to 35% by mass of the methacrylic acid ester monomer 30 minutes or more after the start of the addition of the polymerization initiator. The amount of the methacrylic acid ester monomer to be additionally added is more preferably 10 to 30% by mass, with the total mass of all the monomers to be supplied to the polymerization being 100% by mass.

[0123] The start time of additional addition of the monomer, the speed of additional addition, etc. may be appropriately selected depending on the polymerization conversion rate. Furthermore, in addition to the methacrylic acid ester monomer, a monomer mixture containing the N-substituted maleimide monomer and other monomers may be additionally added within a range that does not impair the effects of the present invention or the increase in the conversion rate of the N-substituted maleimide monomer.

[0124] By employing the semi-batch polymerization method as described above, it is possible to increase the conversion rate of the N-substituted maleimide monomer at the latter stage of the polymerization, reduce the content of the fluorescent substance, provide a lens with a long optical path length with excellent light transmittance, and make it easy to control the molecular weight distribution of the resulting polymer. In particular, it is preferable to obtain a resin and a composition of said resin having flowability suitable for injection molding.

[0125] --Polymerization solvent-- There are no particular limitations on the polymerization solvent, so long as it has high solubility for the maleimide copolymer obtained by polymerization and can appropriately maintain the viscosity of the reaction solution for the purpose of preventing gelation, etc. Specific examples of the polymerization solvent that can be used include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and isopropylbenzene; esters such as methyl isobutyrate; ketones such as methyl isobutyl ketone, butyl cellosolve, methyl ethyl ketone, and cyclohexanone; and polar solvents such as dimethylformamide and 2-methylpyrrolidone. These may be used alone or in combination of two or more. Furthermore, alcohols such as methanol, ethanol, and isopropanol may be used in combination as a polymerization solvent within a range that does not inhibit dissolution of the polymerization product during polymerization.

[0126] The amount of the solvent during polymerization is not particularly limited as long as the polymerization proceeds and the amount can be easily removed without causing precipitation of the copolymer or the monomers used during production. For example, when the total amount of the monomers to be blended is taken as 100% by mass, the amount of the solvent is preferably 10 to 200% by mass, more preferably 25 to 200% by mass, even more preferably 50 to 200% by mass, and even more preferably 50 to 150% by mass. In the above-mentioned production method, a method in which the amount of solvent during polymerization is within a range of 100 mass% or less when the total amount of the monomers to be blended is taken as 100 mass%, while appropriately changing the solvent concentration during polymerization can also be preferably used. More specifically, an example of the method is to blend 40 to 60 mass% in the early stage of polymerization, blend the remaining 60 to 40 mass% during the polymerization, and finally blend the amount of the solvent in a range of 100 mass% or less when the total amount of the blended monomers is 100 mass%. By employing this method, the polymerization conversion rate can be increased, and further, the molecular weight distribution can be controlled, and thus it is possible to obtain a resin and a resin composition that have excellent injection moldability and provide a good color tone even when a lens having a long optical path length is prepared. This is therefore preferable.

[0127] In solution polymerization, it is important to reduce the dissolved oxygen concentration in the polymerization solution as much as possible, and for example, the dissolved oxygen concentration is preferably 10 ppm or less. The dissolved oxygen concentration can be measured, for example, using a dissolved oxygen meter DO meter B-505 (manufactured by Iijima Electronics Co., Ltd.). Methods for reducing the dissolved oxygen concentration can be appropriately selected from a method of bubbling an inert gas into the polymerization solution, a method of repeatedly pressurizing a container containing the polymerization solution to about 0.2 MPa with an inert gas before polymerization and then releasing the pressure, a method of passing an inert gas through a container containing the polymerization solution, and the like.

[0128] The polymerization temperature is not particularly limited as long as it is a temperature at which the polymerization proceeds, but is preferably 70 to 180° C., more preferably 80 to 160° C., even more preferably 90 to 150° C., and even more preferably 100 to 150° C. From the viewpoint of productivity, it is preferable to set the temperature at 70° C. or higher, and it is preferable to set the temperature at 180° C. or lower in order to suppress side reactions during polymerization and obtain a polymer with the desired molecular weight and quality.

[0129] The polymerization time is not particularly limited as long as it is a time that can obtain a required degree of polymerization at a required conversion rate, but from the viewpoint of productivity, etc., it is preferably 2 to 15 hours, more preferably 3 to 12 hours, and even more preferably 4 to 10 hours.

[0130] --Polymerization initiator-- As the polymerization initiator, any initiator generally used in radical polymerization can be used. Examples of the polymerization initiator include organic peroxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, t-amylperoxy-2-ethylhexanoate, t-amylperoxyisononanoate, and 1,1-di(t-butylperoxy)cyclohexane; and azo compounds such as 2,2'-azobis(isobutyronitrile), 1,1'-azobis(cyclohexanecarbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and dimethyl-2,2'-azobisisobutyrate. These may be used alone or in combination of two or more. These polymerization initiators may be added at any stage as long as the polymerization reaction is in progress. The amount of the polymerization initiator added may be 0.01 to 1% by mass, and preferably 0.05 to 0.5% by mass, when the total amount of the monomers used in the polymerization is taken as 100% by mass. The method of adding the polymerization initiator is not particularly limited as long as it is not a constant addition rate but a variable addition rate according to the monomer concentration remaining in the polymerization solution, and may be added continuously or intermittently. When the polymerization initiator is added intermittently, the amount added per unit time is not considered for the time when the polymerization initiator is not added.

[0131] In the above-mentioned production method, it is preferable to appropriately select the type and amount of the polymerization initiator, the polymerization temperature, etc. so that the ratio of the total amount of radicals generated from the polymerization initiator to the total amount of unreacted monomers remaining in the reaction system is always equal to or less than a certain value. By employing these methods, it is possible to suppress the production of oligomers and low molecular weight materials in the later stages of polymerization, and to prevent overheating during polymerization, thereby ensuring the stability of the polymerization.

[0132] --Chain transfer agent-- During the polymerization reaction, a chain transfer agent may be added as necessary. As the chain transfer agent, any chain transfer agent used in general radical polymerization can be used, and examples thereof include mercaptan compounds such as n-butyl mercaptan, n-octyl mercaptan, n-decyl mercaptan, n-dodecyl mercaptan, 2-ethylhexyl thioglycolate, etc.; halogen compounds such as carbon tetrachloride, methylene chloride, bromoform, etc.; unsaturated hydrocarbon compounds such as α-methylstyrene dimer, α-terpinene, dipentene, terpinolene, etc.; and the like. These may be used alone or in combination of two or more. These chain transfer agents may be added at any stage as long as the polymerization reaction is in progress, and there are no particular limitations on the addition stage. The amount of the chain transfer agent added may be 0.01 to 1 part by mass, and preferably 0.05 to 0.5 part by mass, based on 100 parts by mass of the total amount of monomers used in the polymerization.

[0133] The method for recovering the polymer from the polymerization liquid obtained by solution polymerization is not particularly limited, and examples thereof include a method in which the polymerization liquid is added to an excess of a poor solvent such as a hydrocarbon solvent or an alcohol solvent in which the polymerization product obtained by polymerization is not dissolved, and then the mixture is treated with a homogenizer (emulsion dispersion), and unreacted monomers are separated from the polymerization liquid by pretreatment such as liquid-liquid extraction or solid-liquid extraction; or a method in which the polymerization solvent and unreacted monomers are separated via a process called a devolatilization process, and the polymerization product is recovered. The devolatilization step here refers to a step of removing volatile matters such as the polymerization solvent, residual monomers, and reaction by-products under heating and reduced pressure conditions.

[0134] --Devolatilization process-- The apparatus used in the devolatilization step may be, for example, a devolatilization apparatus consisting of a tubular heat exchanger and a devolatilization tank. Other examples of the apparatus having a rotating part include thin-film evaporators such as Wiblen and Exeva manufactured by Kobelco Eco-Solutions Co., Ltd., Contra and tilted blade Contra manufactured by Hitachi, Ltd., and vented extruders having a residence time and surface area sufficient to exhibit devolatilization performance. A devolatilization step using a devolatilization apparatus that combines two or more of these devices can also be used.

[0135] Regarding the resin composition constituting the molded body, in order to obtain a resin composition with high transmittance in the near infrared region and small haze, the generation of by-products must be suppressed, and in order to obtain a methacrylic resin with good transparency, for example, a method of polymerization in which the polymerization time is extended as much as possible to increase the monomer conversion rate, or the rate of polymerization initiator addition is changed according to the concentration of unreacted monomers in the polymerization solution; a method of polymerization while appropriately changing the solvent concentration during polymerization; or a method of additionally adding another monomer that is highly reactive with the N-substituted maleimide monomer remaining in the latter half of polymerization can be used. By suppressing the reaction by-products, a resin composition with high transparency and small haze can be obtained, and therefore a resin window member can be produced that can obtain processed data (including images) with high contrast and no whiteout.

[0136] From the viewpoint of achieving high transparency and improving color tone, it is preferable to use a volatilization apparatus that is mainly composed of a heat exchanger and a reduced pressure vessel and does not have a rotating part in its structure. Specifically, a volatilizing apparatus can be used which is composed of a volatilizing tank having a reduced pressure vessel with a heat exchanger disposed on the upper portion thereof and a size allowing volatilization, to which a reduced pressure unit is attached, and a discharge device such as a gear pump for discharging the polymer after volatilization. In the above-mentioned volatilizing apparatus, the polymerization solution is preheated by being fed to a heated heat exchanger, such as a multi-tube heat exchanger, a plate fin heat exchanger, or a flat plate heat exchanger having a flat plate flow path and a heater, which is disposed in the upper part of the reduced pressure vessel, and then fed to a volatilizing tank which is heated and under reduced pressure, to separate and remove the polymerization solvent, the unreacted raw material mixture, the polymerization by-products, and the copolymer. The use of a volatilizing apparatus having no rotating part as described above is preferable because it allows the production of a methacrylic resin having a good color tone.

[0137] In the above-mentioned manufacturing method, the heat exchanger disposed in the upper part of the reduced pressure vessel is preferably a flat plate type heat exchanger having a flat plate type flow path and a heater, more preferably a flat plate type heat exchanger having a heater and a flat plate type flow path having a laminated structure having a plurality of slit-shaped flow paths each having a rectangular cross section on the same plane.

[0138] The polymerization solution fed to the volatilizer is sent from the center of the heat exchanger to the slit-shaped flow passage and heated. The heated polymerization solution is fed from the slit-shaped flow passage into a reduced pressure vessel integrated with the heat exchanger under reduced pressure and flash evaporated. Such a devolatilization method is also called flash devolatilization, and will hereinafter be referred to as flash devolatilization.

[0139] The treatment temperature in the devolatilizer is a temperature of glass transition temperature (Tg) of the methacrylic resin + 100° C. to Tg + 160° C. Specifically, the treatment temperature is preferably 150 to 350° C., more preferably 180 to 310° C., and further preferably 200 to 290° C. By setting the temperature at or above the lower limit temperature, the remaining volatile matter can be suppressed, and by setting the temperature at or below the upper limit temperature, coloration and decomposition of the obtained methacrylic resin can be suppressed.

[0140] The degree of vacuum in the volatilizing tank may be in the range of 5 to 300 Torr, and preferably in the range of 10 to 200 Torr. When the degree of vacuum is 300 Torr or less, the unreacted monomer or the mixture of the unreacted monomer and the polymerization solvent can be efficiently separated and removed, and the thermal stability and quality of the obtained thermoplastic copolymer are not deteriorated. When the degree of vacuum is 5 Torr or more, industrial implementation is easier.

[0141] The average residence time in the devolatilization tank is 5 to 60 minutes, preferably 5 to 45 minutes. When the average residence time is within this range, devolatilization can be performed efficiently and coloration and decomposition of the polymer due to thermal denaturation can be suppressed, which is preferable.

[0142] The polymer recovered through the devolatilization step is processed into pellets in a step called a granulation step. In the granulation process, the molten resin is extruded in a strand shape using at least one type of discharge granulation device selected from a gear pump having a multi-hole die as an auxiliary equipment, a single-screw extruder, a twin-screw extruder, etc., and processed into pellets using a cold cut method, an air hot cut method, an underwater strand cut method, or an underwater cut method.

[0143] In the above-mentioned manufacturing method, in order to obtain a highly controlled resin composition, it is preferable to adopt a granulation method that can quickly cool and solidify the resin composition in a molten state at high temperature while minimizing contact with air as much as possible. In this case, it is more preferable to carry out granulation under conditions in which the molten resin temperature is as low as possible, the residence time from the multi-hole die outlet to the cooling water surface is as short as possible, and the cooling water temperature is as high as possible. For example, the molten resin temperature is preferably 220 to 280°C, and more preferably 230 to 270°C, the residence time from the multi-hole die outlet to the cooling water surface is preferably within 5 seconds, and more preferably within 3 seconds, and the cooling water temperature is preferably in the range of 30 to 80°C, and more preferably 40 to 60°C.

[0144] By carrying out the process within these ranges of the molten resin temperature and the cooling water temperature, it is possible to obtain a methacrylic resin and a composition thereof which are less colored and have a low moisture content, which is preferable.

[0145] The smaller the content of the monomer remaining in the methacrylic resin after the devolatilization step, the better from the viewpoint of thermal stability and product quality. Specifically, the content of the methacrylic acid ester monomer is preferably 3000 mass ppm or less, more preferably 2000 mass ppm or less. The content of the N-substituted maleimide monomer is preferably 200 mass ppm or less in total, more preferably 100 mass ppm or less. The content of the residual polymerization solvent is preferably 500 ppm by mass or less, and more preferably 300 ppm by mass or less.

[0146] -Method for producing methacrylic resin containing glutarimide structural unit- Examples of a method for producing a methacrylic resin having a glutarimide structural unit in the main chain include a bulk polymerization method, a solution polymerization method, a suspension polymerization method, a precipitation polymerization method, and an emulsion polymerization method. Of these, the suspension polymerization method, the bulk polymerization method, and the solution polymerization method are preferred, and the solution polymerization method is more preferred. In the above-mentioned production method, any of a batch polymerization method, a semi-batch polymerization method, and a continuous polymerization method can be used as the polymerization type. In the above production method, it is preferable to polymerize the monomers by radical polymerization.

[0147] Methacrylic resins having glutarimide structural units in the main chain are, for example, methacrylic resins having glutarimide structural units described in JP 2006-249202 A, JP 2007-009182 A, JP 2007-009191 A, JP 2011-186482 A, WO 2012 / 114718 A, and the like, and can be formed by the methods described in these publications. Hereinafter, as an example of a method for producing a methacrylic resin having a glutarimide structural unit, a batch-type radical polymerization method using a solution polymerization method will be specifically described.

[0148] First, a (meth)acrylic acid ester such as methyl methacrylate is polymerized to produce a (meth)acrylic acid ester polymer. When an aromatic vinyl unit is to be contained in a methacrylic resin having a glutarimide structural unit, a (meth)acrylic acid ester and an aromatic vinyl (e.g., styrene) are copolymerized to produce a (meth)acrylic acid ester-aromatic vinyl copolymer.

[0149] Examples of the solvent used in the polymerization include aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; ketones such as methyl ethyl ketone and methyl isobutyl ketone; and the like. These solvents may be used alone or in combination of two or more kinds. The amount of the solvent during polymerization is not particularly limited as long as the polymerization proceeds and the amount can be easily removed without causing precipitation of the copolymer or monomers used during production, but for example, when the total amount of the monomers to be blended is taken as 100 mass%, the amount is preferably 10 to 200 mass%, more preferably 25 to 200 mass%, even more preferably 50 to 200 mass%, and even more preferably 50 to 150 mass%.

[0150] The polymerization temperature is not particularly limited as long as it is a temperature at which the polymerization proceeds, but is preferably 50 to 200° C., more preferably 80 to 200° C., even more preferably 90 to 150° C., even more preferably 100 to 140° C., and even more preferably 100 to 130° C. From the viewpoint of productivity, it is preferably 70° C. or higher, and is preferably 180° C. or lower in order to suppress side reactions during polymerization and to obtain a polymer with the desired molecular weight and quality. The polymerization time is not particularly limited as long as the target conversion rate is achieved, but from the viewpoint of productivity, etc., it is preferably 0.5 to 15 hours, more preferably 2 to 12 hours, and further preferably 4 to 10 hours.

[0151] During the polymerization reaction, a polymerization initiator or a chain transfer agent may be added as necessary.

[0152] The polymerization initiator is not particularly limited, but for example, the polymerization initiators disclosed in the method for preparing the methacrylic resin having a structural unit derived from the N-substituted maleimide monomer can be used. These polymerization initiators may be used alone or in combination of two or more kinds. These polymerization initiators may be added at any stage as long as the polymerization reaction is in progress. The amount of the polymerization initiator added may be appropriately set depending on the combination of monomers, reaction conditions, etc., and is not particularly limited. When the total amount of the monomers used in the polymerization is taken as 100% by mass, the amount may be 0.01 to 1% by mass, and preferably 0.05 to 0.5% by mass.

[0153] As the chain transfer agent, a chain transfer agent used in general radical polymerization can be used, for example, the chain transfer agents disclosed in the above-mentioned method for preparing a methacrylic resin having a structural unit derived from an N-substituted maleimide monomer can be used. These may be used alone or in combination of two or more. These chain transfer agents may be added at any stage as long as the polymerization reaction is in progress, and there are no particular limitations on the addition stage. The amount of the chain transfer agent to be added is not particularly limited as long as it is within a range in which a desired degree of polymerization can be obtained under the polymerization conditions used, but is preferably 0.01 to 1 mass %, and more preferably 0.05 to 0.5 mass %, when the total amount of the monomers used in the polymerization is taken as 100 mass %.

[0154] In the polymerization step, a suitable method for adding a polymerization initiator and a chain transfer agent may be, for example, the method described in the above-mentioned method for preparing a methacrylic resin having a structural unit derived from an N-substituted maleimide monomer. The dissolved oxygen concentration in the polymerization solution may be, for example, the value disclosed in the above-mentioned method for preparing a methacrylic resin having a structural unit derived from an N-substituted maleimide monomer.

[0155] Next, the (meth)acrylic acid ester polymer or the methacrylic acid ester-aromatic vinyl copolymer is reacted with an imidizing agent to carry out an imidization reaction (imidization step), thereby producing a methacrylic resin having a glutarimide structural unit.

[0156] The imidizing agent is not particularly limited as long as it can generate the glutarimide structural unit represented by the general formula (3) above. Specifically, the imidizing agent may be ammonia or a primary amine. Examples of the primary amine include aliphatic hydrocarbon group-containing primary amines such as methylamine, ethylamine, n-propylamine, i-propylamine, n-butylamine, i-butylamine, tert-butylamine, and n-hexylamine; alicyclic hydrocarbon group-containing primary amines such as cyclohexylamine; and the like. Of the above imidizing agents, ammonia, methylamine and cyclohexylamine are preferred from the standpoint of cost and physical properties, with methylamine being particularly preferred.

[0157] In this imidization step, the content of glutarimide structural units in the resulting methacrylic resin having glutarimide structural units can be adjusted by adjusting the ratio of the imidization agent added.

[0158] The method for carrying out the imidization reaction is not particularly limited, and a conventionally known method can be used. For example, the imidization reaction can be carried out using an extruder or a batch-type reaction tank.

[0159] The extruder is not particularly limited, but for example, a single screw extruder, a twin screw extruder, a multi-screw extruder, etc. can be used. Among these, it is preferable to use a twin-screw extruder, which can promote mixing of the raw material polymer and the imidizing agent. Examples of twin-screw extruders include non-intermeshing co-rotating, intermeshing co-rotating, non-intermeshing counter-rotating, and intermeshing counter-rotating. The above-mentioned extruders may be used alone or in combination of a plurality of extruders connected in series. It is particularly preferable to equip the extruder to be used with a vent port capable of reducing the pressure to below atmospheric pressure, since this makes it possible to remove by-products of the reaction such as the imidizing agent, methanol, and the like, or monomers.

[0160] In producing a methacrylic resin having a glutarimide structural unit, in addition to the above-mentioned imidization step, an esterification step of treating the carboxyl group of the resin with an esterification agent such as dimethyl carbonate can be included. In this case, a catalyst such as trimethylamine, triethylamine, or tributylamine can also be used in combination for the treatment. The esterification step can be carried out, for example, by using an extruder or a batch reaction tank, in the same manner as in the imidization step. For the purpose of removing excess esterifying agent, by-products such as methanol, or monomers, the apparatus used is preferably equipped with a vent port capable of reducing the pressure to atmospheric pressure or below. At this time, if the carboxyl groups are not esterified, the remaining carboxyl groups will increase the water absorption rate of the resin, causing peeling of the bonding surface with the housing in a reliability test under a high humidity environment, and also causing peeling of the bonding surface when a near-infrared compatible polarizing element is bonded to a molded body for use, which will also lead to deterioration of the surface accuracy. Also, if the esterifying agent such as dimethyl carbonate or amines are not sufficiently volatilized, acidic substances and alkaline substances will remain, which is also undesirable because it can cause peeling of the bonding surface and deterioration of the metal wires of the wire grid polarizing element when a near-infrared compatible polarizing element is bonded to a molded body for use.

[0161] The methacrylic resin that has been subjected to the imidization step and, if necessary, the esterification step is melted and extruded in the form of strands from an extruder equipped with a multi-hole die, and processed into pellets by a cold cut method, an in-air hot cut method, an underwater strand cut method, an underwater cut method, or the like. In order to reduce the number of foreign matters in the resin, it is also preferable to use a method in which the methacrylic resin is dissolved in an organic solvent such as toluene, methyl ethyl ketone, or methylene chloride, the obtained methacrylic resin solution is filtered, and then the organic solvent is removed.

[0162] From the viewpoint of reducing the fluorescence intensity (content of the fluorescent substance), it is preferable to imidize the polymer solution after the completion of the polymerization in a batch reaction tank without using a twin-screw extruder that is subjected to a shearing force. The imidization reaction is preferably carried out at 130 to 250° C., more preferably at 150 to 230° C., and even more preferably at 170 to 190° C. The reaction time is preferably 10 minutes to 5 hours, and more preferably 30 minutes to 2 hours. After the imidization step, an esterification step may be carried out as necessary, and then the volatilization is carried out by the volatilization method described in the above-mentioned method for preparing a methacrylic resin having a structural unit derived from an N-substituted maleimide monomer, followed by pelletization, which is preferable from the viewpoint of reducing the fluorescence intensity.

[0163] -Method for producing methacrylic resin containing lactone ring structural unit- As a method for producing a methacrylic resin having a lactone ring structural unit in the main chain, a method in which a lactone ring structure is formed by a cyclization reaction after polymerization is used. In order to promote the cyclization reaction, however, it is preferable to polymerize monomers by radical polymerization using a solution polymerization method using a solvent. In the above-mentioned production method, any of a batch polymerization method, a semi-batch polymerization method, and a continuous polymerization method can be used as the polymerization type. Methacrylic resins having a lactone ring structural unit in the main chain can be formed by the methods described in, for example, JP-A Nos. 2001-151814, 2004-168882, 2005-146084, 2006-96960, 2006-171464, 2007-63541, 2007-297620, and 2010-180305.

[0164] As an example of a method for producing a methacrylic resin having a lactone ring structural unit, a batchwise radical polymerization method using a solution polymerization method will be specifically described below. As a method for producing a methacrylic resin having a lactone ring structural unit, a method of forming a lactone ring structure by a cyclization reaction after polymerization is used. In order to promote the cyclization reaction, solution polymerization using a solvent is preferred.

[0165] Examples of the solvent used in the polymerization include aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; ketones such as methyl ethyl ketone and methyl isobutyl ketone; and the like. These solvents may be used alone or in combination of two or more kinds.

[0166] The amount of the solvent during polymerization is not particularly limited as long as the polymerization proceeds and gelation can be suppressed. For example, the amount of the solvent is preferably 50 to 200% by mass, and more preferably 100 to 200% by mass, assuming that the total amount of the monomers to be blended is 100% by mass.

[0167] In order to sufficiently suppress gelation of the polymerization solution and promote the cyclization reaction after polymerization, it is preferable to carry out the polymerization so that the concentration of the produced polymer in the reaction mixture obtained after polymerization is 50% by mass or less. It is also preferable to control the concentration to 50% by mass or less by adding a polymerization solvent to the reaction mixture as appropriate.

[0168] The method for appropriately adding the polymerization solvent to the reaction mixture is not particularly limited, and for example, the polymerization solvent may be added continuously or intermittently. The polymerization solvent to be added may be a single solvent or a mixed solvent of two or more solvents. The polymerization temperature is not particularly limited as long as the polymerization proceeds at the temperature, but is preferably 50 to 200°C, more preferably 80 to 180°C, from the viewpoint of productivity. The polymerization time is not particularly limited as long as the target conversion rate is achieved, but from the viewpoint of productivity, etc., it is preferably 0.5 to 10 hours, more preferably 1 to 8 hours.

[0169] During the polymerization reaction, a polymerization initiator or a chain transfer agent may be added, if necessary. The polymerization initiator is not particularly limited, but for example, the polymerization initiators disclosed in the method for preparing the methacrylic resin having a structural unit derived from the N-substituted maleimide monomer can be used. These polymerization initiators may be used alone or in combination of two or more kinds. These polymerization initiators may be added at any stage as long as the polymerization reaction is in progress. The amount of the polymerization initiator to be added may be appropriately set depending on the combination of monomers, reaction conditions, etc., and is not particularly limited. When the total amount of the monomers used in the polymerization is taken as 100% by mass, the amount may be 0.05 to 1% by mass.

[0170] As the chain transfer agent, a chain transfer agent used in general radical polymerization can be used, for example, the chain transfer agents disclosed in the above-mentioned method for preparing a methacrylic resin having a structural unit derived from an N-substituted maleimide monomer can be used. These may be used alone or in combination of two or more. These chain transfer agents may be added at any stage as long as the polymerization reaction is in progress, and there are no particular limitations on the addition stage. The amount of the chain transfer agent to be added is not particularly limited as long as the desired degree of polymerization is obtained under the polymerization conditions used, but is preferably 0.05 to 1 mass % when the total amount of the monomers to be used in the polymerization is taken as 100 mass %.

[0171] In the polymerization step, a suitable method for adding a polymerization initiator and a chain transfer agent may be, for example, the method described in the above-mentioned method for preparing a methacrylic resin having a structural unit derived from an N-substituted maleimide monomer.

[0172] The dissolved oxygen concentration in the polymerization solution may be, for example, the value disclosed in the above-mentioned method for preparing a methacrylic resin having a structural unit derived from an N-substituted maleimide monomer.

[0173] The methacrylic resin having a lactone ring structural unit can be obtained by carrying out a cyclization reaction after the completion of the polymerization reaction. Therefore, it is preferable to subject the polymerization reaction solution to the lactone cyclization reaction while it contains the solvent, without removing the polymerization solvent from the polymerization reaction solution. When the copolymer obtained by polymerization is heat-treated, a cyclization condensation reaction occurs between the hydroxyl groups (hydroxyl groups) and ester groups present in the molecular chain of the copolymer, forming a lactone ring structure. In the heat treatment for forming the lactone ring structure, a reaction apparatus equipped with a vacuum device or a volatilizing device, an extruder equipped with a volatilizing device, or the like can be used to remove alcohol that may be by-produced by the cyclocondensation.

[0174] When forming the lactone ring structure, a heat treatment may be carried out using a cyclization condensation catalyst, if necessary, in order to promote the cyclization condensation reaction. Specific examples of the cyclization condensation catalyst include monoalkyl phosphite, dialkyl ester, or triester phosphite, such as methyl phosphite, ethyl phosphite, phenyl phosphite, dimethyl phosphite, diethyl phosphite, diphenyl phosphite, trimethyl phosphite, and triethyl phosphite; monoalkyl phosphate, dialkyl ester, or trialkyl ester phosphate, such as methyl phosphate, ethyl phosphate, 2-ethylhexyl phosphate, octyl phosphate, isodecyl phosphate, lauryl phosphate, stearyl phosphate, isostearyl phosphate, dimethyl phosphate, diethyl phosphate, di-2-ethylhexyl phosphate, diisodecyl phosphate, dilauryl phosphate, distearyl phosphate, diisostearyl phosphate, trimethyl phosphate, triethyl phosphate, triisodecyl phosphate, trilauryl phosphate, tristearyl phosphate, and triisostearyl phosphate; and organic zinc compounds, such as zinc acetate, zinc propionate, and zinc octyl. These may be used alone or in combination of two or more.

[0175] The amount of the cyclization condensation catalyst used is not particularly limited, but is, for example, preferably 0.01 to 3 mass %, and more preferably 0.05 to 1 mass %, relative to 100 mass % of the methacrylic resin. When the amount of the catalyst used is 0.01% by mass or more, it is effective in improving the reaction rate of the cyclization condensation reaction, and when the amount of the catalyst used is 3% by mass or less, it is effective in preventing the obtained polymer from being discolored or from being crosslinked, which makes it difficult to melt mold the polymer.

[0176] The timing of adding the cyclization condensation catalyst is not particularly limited, and for example, it may be added at the beginning of the cyclization condensation reaction, or during the reaction, or it may be added at both times. When the cyclization condensation reaction is carried out in the presence of a solvent, devolatilization can also be carried out at the same time.

[0177] The apparatus used when the cyclocondensation reaction and the devolatilization step are carried out simultaneously is not particularly limited, but a devolatilization apparatus consisting of a heat exchanger and a devolatilization tank, an extruder equipped with a vent, or an apparatus in which a devolatilization apparatus and an extruder are arranged in series is preferable, and a twin-screw extruder equipped with a vent is more preferable. The vented twin-screw extruder used is preferably one having a plurality of vent ports.

[0178] When a vented extruder is used, the reaction temperature is preferably 150 to 350° C., more preferably 200 to 300° C. If the reaction temperature is less than 150° C., the cyclization condensation reaction may be insufficient, resulting in a large amount of residual volatile matter. Conversely, if the reaction temperature exceeds 350° C., the resulting polymer may become discolored or decomposed. When using a vented extruder, the degree of vacuum is preferably 10 to 500 Torr, more preferably 10 to 300 Torr. If the degree of vacuum exceeds 500 Torr, volatile matter may easily remain. Conversely, if the degree of vacuum is less than 10 Torr, industrial implementation may be difficult.

[0179] When the above cyclization condensation reaction is carried out, it is also preferred to add an alkaline earth metal and / or amphoteric metal salt of an organic acid during granulation for the purpose of deactivating the remaining cyclization condensation catalyst. Examples of the alkaline earth metal and / or amphoteric metal salt of an organic acid that can be used include calcium acetylacetate, calcium stearate, zinc acetate, zinc octoate, and zinc 2-ethylhexylate.

[0180] After the cyclocondensation reaction step, the methacrylic resin is melted and extruded in the form of strands from an extruder equipped with a multi-hole die, and processed into pellets by a cold cut method, an in-air hot cut method, an underwater strand cut method, or an underwater cut method. The lactonization for forming the lactone ring structural unit may be carried out after the production of the resin and before the production of the resin composition (described later), or may be carried out during the production of the resin composition, together with melt-kneading of the resin and components other than the resin.

[0181] From the viewpoint of reducing the fluorescence intensity (content of the fluorescent substance), it is preferable to lactone-cyclize the polymerization solution after the completion of the polymerization in a batch-type reaction tank without using a twin-screw extruder that is subjected to a shearing force. After the lactone-cyclization step, it is preferable to pelletize the solution after devolatilization by the devolatilization method described in the above-mentioned method for preparing a methacrylic resin having a structural unit derived from an N-substituted maleimide monomer, from the viewpoint of reducing the fluorescence intensity.

[0182] -Method for producing methacrylic resin containing hydrogenated aromatic ring structural unit- As a method for producing a methacrylic resin having a hydrogenated aromatic ring structural unit, a method is used in which a copolymer of an aromatic vinyl compound and a (meth)acrylate is hydrogenated in the presence of a hydrogenation catalyst and a reaction solvent to produce a nuclear-hydrogenated polymer. The method of polymerizing the aromatic vinyl compound and the monomer containing (meth)acrylate can be a known method, but the radical polymerization method is industrially convenient. The radical polymerization can be appropriately selected from known methods such as bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization, but it is preferable to manufacture by bulk polymerization or solution polymerization in order to avoid the inclusion of moisture during the hydrogenation reaction. In the above-mentioned manufacturing method, the polymerization form can be, for example, any of the batch polymerization method, semi-batch method, and continuous polymerization method. Methacrylic resins containing hydrogenated aromatic ring structural units can be formed, for example, by the methods described in JP-A-2006-291184, JP-A-2006-291184, JP-A-2014-77043, JP-A-2014-77044, and the like.

[0183] Hereinafter, an example of a method for producing a methacrylic resin containing a hydrogenated aromatic ring structural unit obtained by hydrogenating a copolymer of an aromatic vinyl compound and a (meth)acrylate will be specifically described.

[0184] The solvent used in the polymerization must be stable under the reaction conditions, and must have good solubility of the copolymer (a copolymer of an aromatic vinyl compound and a (meth)acrylate, and a nuclear hydrogenated polymer in which an aromatic ring is hydrogenated) and good solubility of hydrogen before and after the hydrogenation reaction, and must also be capable of carrying out the reaction quickly. In addition, when considering the degassing of the solvent components after the reaction, it is also important that the ignition point of the solvent is high. Examples of solvents that satisfy these requirements include hydrocarbon compounds such as n-pentane, n-hexane, n-octane, and cyclohexane, ether compounds such as 1,4-dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether, amide compounds such as dimethylformamide and dimethylacetamide, and ester compounds, with ether compounds and ester compounds being particularly preferred. Tetrahydrofuran is particularly preferred as an ether compound. These solvents may be used alone or in combination of two or more.

[0185] As the ester compound, a carboxylic acid ester compound is preferred. As the carboxylic acid ester compound, an aliphatic ester compound is used, and a compound represented by the following general formula (5) is preferred. In the formula, R1 is an alkyl group having 1 to 6 carbon atoms, and R2 is an alkyl group having 1 to 6 carbon atoms. Examples of R1 and R2 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, a hexyl group, and a cyclohexyl group. As the ester compound, methyl acetate, ethyl acetate, n-butyl acetate, pentyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, n-butyl propionate, methyl n-butyrate, methyl isobutyrate, n-butyl n-butyrate, methyl n-valerate, methyl n-hexanoate, etc. are used, and in particular, methyl acetate, ethyl acetate, methyl propionate, methyl isobutyrate, and methyl n-butyrate are more preferred. R1-COO-R2...(5)

[0186] The concentration of the copolymer (a copolymer of an aromatic vinyl compound and a (meth)acrylate, and a nuclear hydrogenated polymer in which an aromatic ring has been hydrogenated) in the solution during the hydrogenation reaction is usually 1 to 50% by weight, preferably 3 to 30% by weight, and more preferably 5 to 25% by weight. If the concentration of the copolymer is too high, it is undesirable from the standpoints of a slower reaction rate and inconvenience in handling due to an increase in the viscosity of the solution, while if the concentration is low, it is undesirable from the standpoints of productivity and economy.

[0187] The water concentration in the polymer solution before the hydrogenation reaction is 0.5% by weight or less, preferably 0.2% by weight or less, and more preferably 0.05% by weight or less. If the water content exceeds 0.5% by weight, the produced nuclear hydrogenated polymer (pellets, powder) may become colored, which is not preferable as an optical material.

[0188] During the polymerization reaction, a polymerization initiator or a chain transfer agent can be added as necessary, but since sulfur inhibits the hydrogenation reaction, it is desirable to avoid the inclusion of sulfur as much as possible. The polymerization initiator is not particularly limited as long as it does not have a sulfur functional group. For example, the polymerization initiator disclosed in the above-mentioned method for preparing a methacrylic resin having a structural unit derived from an N-substituted maleimide monomer can be used. These polymerization initiators may be used alone or in combination of two or more kinds. These polymerization initiators may be added at any stage as long as the polymerization reaction is in progress. The amount of the polymerization initiator to be added may be appropriately set depending on the combination of monomers, reaction conditions, etc., and is not particularly limited. When the total amount of the monomers used in the polymerization is taken as 100% by mass, the amount may be 0.05 to 1% by mass.

[0189] In the polymerization step, a suitable method for adding a polymerization initiator and a chain transfer agent may be, for example, the method described in the above-mentioned method for preparing a methacrylic resin having a structural unit derived from an N-substituted maleimide monomer.

[0190] The dissolved oxygen concentration in the polymerization solution may be, for example, the value disclosed in the above-mentioned method for preparing a methacrylic resin having a structural unit derived from an N-substituted maleimide monomer.

[0191] Chain transfer agents are not necessarily required. If used, it is preferable to use carbon tetrahalides such as carbon tetrachloride, carbon tetrabromide, and carbon tetraiodide, or styrene dimers such as 2,4-diphenyl-4-methyl-1-pentene. Mercaptan compound-based chain transfer agents, which are commonly used, are not preferable because they introduce sulfur functional groups to the polymer terminals and inhibit the hydrogenation reaction of aromatic rings. These may be used alone or in combination of two or more. These chain transfer agents may be added at any stage as long as the polymerization reaction is in progress, and there are no particular limitations on the addition stage. The amount of the chain transfer agent to be added is not particularly limited as long as the desired degree of polymerization is obtained under the polymerization conditions used, but is preferably 0.05 to 1 mass % when the total amount of the monomers to be used in the polymerization is taken as 100 mass %. Generally, when a mercaptan compound-based chain transfer agent is not used, the thermal decomposition property of the raw polymer decreases. However, in the case of a methacrylic resin containing an aromatic ring hydrogenated structural unit, the physical properties such as the decomposition temperature depend only on the hydrogenation rate, and if the hydrogenation rate is the same, the use of a sulfur-based chain transfer agent does not affect the decomposition temperature.

[0192] The catalyst (hydrogenation catalyst) used in the hydrogenation reaction is not particularly limited as long as it has hydrogenation activity. Specific examples include nickel, ruthenium, rhodium, palladium, platinum, etc. Among these, palladium supported on a carrier is particularly preferred, as it has a high reaction rate and the solvent is retained before and after the reaction without causing side reactions. Generally, the catalyst carrier is selected from activated carbon, alumina (Al 2 O 3 ), silica (SiO 2 ), silica-alumina (SiO 2 -Al 2 O 3 ), diatomaceous earth, zirconium oxide, etc. The catalyst carrier in the present invention is not limited, but it is preferable to use activated carbon, alumina, or zirconium oxide.

[0193] The amount of palladium metal supported on the carrier is usually in the range of 0.01 to 50% by weight, preferably 0.05 to 20% by weight, and more preferably 0.1 to 10% by weight. From an economical point of view, it is preferable to use as little palladium as possible, which is an expensive metal. However, when activated carbon or zirconium oxide is used as the carrier, it is possible to support palladium in a highly dispersed state, and since the reaction rate per unit palladium is very high, a sufficient reaction rate can be maintained even when the amount of palladium supported is 0.1 to 1.0% by weight. The degree of dispersion of palladium is measured using a known method such as a carbon monoxide pulse adsorption method.

[0194] As the precursor of palladium, known salts or complexes such as palladium chloride, palladium nitrate, palladium acetate, etc. can be used. When the precursor is impregnated and supported on the support, it is made into a solution, and examples of combinations of precursor solutions (precursor / solvent) include palladium chloride / hydrochloric acid water, palladium chloride / sodium chloride water, palladium nitrate / water, palladium nitrate / hydrochloric acid water, palladium acetate / hydrochloric acid water, and palladium acetate / organic solvent.

[0195] The preferred conditions for the hydrogenation reaction are a temperature of 60 to 250°C, a hydrogen pressure of 3 to 30 MPa, and a reaction time of 3 to 20 hours. If the reaction temperature is too low, the reaction rate will be slow, and if the reaction temperature is too high, side reactions such as polymer decomposition and solvent hydrogenolysis will occur, which is not preferred. In addition, if the hydrogen pressure is low, the reaction rate will be slow, and conversely, if the hydrogen pressure is to be further increased, a high-pressure reactor will be required, which is not economically preferred.

[0196] The hydrogenation catalyst and volatile components (solvent, etc.) can be separated from the polymer solution after the hydrogenation reaction to obtain a nuclear-hydrogenated polymer. The catalyst can be separated by known methods such as filtration or centrifugation. Considering coloration and effects on mechanical properties, the concentration of residual catalyst metal in the polymer must be as low as possible, preferably 10 ppm or less, and more preferably 1 ppm or less.

[0197] As a method for purifying the polymer by separating volatile components such as the solvent from the obtained nuclear-hydrogenated polymer solution after separating the catalyst, it is preferable to remove volatile components by the volatilization method described in the above-mentioned method for preparing a methacrylic resin having a structural unit derived from an N-substituted maleimide monomer, and then pelletize the polymer, from the viewpoint of reducing the fluorescence intensity.

[0198] -Additives- The resin composition constituting the molded body contained in the resin window member according to this embodiment may contain various additives within ranges that do not significantly impair the effects of the present invention. The additives are not particularly limited, and examples thereof include antioxidants, light stabilizers such as hindered amine light stabilizers, ultraviolet absorbers, release agents, thermoplastic resins other than methacrylic resins, softeners / plasticizers such as paraffinic process oil, naphthenic process oil, aromatic process oil, paraffin, organic polysiloxane, and mineral oil, flame retardants, antistatic agents, inorganic fillers such as organic fibers and pigments such as iron oxide, reinforcing agents such as glass fibers, carbon fibers, and metal whiskers, colorants, organic phosphorus compounds such as phosphites, phosphonites, and phosphate esters, other additives, and mixtures thereof.

[0199] -Antioxidants- The resin composition constituting the molded body contained in the resin window member according to this embodiment preferably contains an antioxidant that suppresses deterioration and coloration during molding or use. The antioxidant includes, but is not limited to, hindered phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, and the like. These antioxidants may be used alone or in combination of two or more. From the viewpoint of improving thermal stability and suppressing molding defects, it is preferable to use multiple types of heat stabilizers in combination. For example, it is preferable to use at least one selected from a phosphorus-based antioxidant and a sulfur-based antioxidant in combination with a hindered phenol-based antioxidant.

[0200] Examples of the hindered phenol-based antioxidant include, but are not limited to, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 3,3',3'',5,5',5''-hexa-tert-butyl-a,a',a''-(mesitylene-2,4,6-triyl)tri-p-cresol, 4,6-bis(octylthiomethyl)-o-cresol, 4,6-bis(dodecylthiomethyl)-o-cresol, ethylene bis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylene bis[ 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris[(4-tert-butyl-3-hydroxy-2,6-xylin)methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2 ,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamine)phenol, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, 2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl acrylate, and the like. In particular, pentaerythritol terakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, and 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate are preferred.

[0201] In addition, as the hindered phenol-based antioxidant as the antioxidant, a commercially available phenol-based antioxidant may be used. Examples of such commercially available phenol-based antioxidants include, but are not limited to, Irganox 1010 (Irganox 1010: pentaerythritol tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], manufactured by BASF), Irganox 1076 (Irganox 1076: Octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, BASF), Irganox 1330 (Irganox 1330: 3,3',3'',5,5',5''-hexa-t-butyl-a,a',a''-(mesitylene-2,4,6-triyl)tri-p-cresol, BASF), Irganox 3114 (Irganox 3114: 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, B ASF), Irganox 3125 (BASF), Adeka STAB AO-60 (pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], ADEKA), Adeka STAB AO-80 (3,9-bis{2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane, ADEKA), Sumilizer BHT (Sumilizer BHT, manufactured by Sumitomo Chemical), Cyanox 1790 (manufactured by Cytec), Sumilizer GA-80 (manufactured by Sumitomo Chemical), Sumilizer GS (Sumilizer GS: 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, manufactured by Sumitomo Chemical), Sumilizer GM (Sumilizer GM: 2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl acrylate, manufactured by Sumitomo Chemical), and Vitamin E (manufactured by Eisai). Among these commercially available phenolic antioxidants, Irganox 1010, Adeka STAB AO-60, Adeka STAB AO-80, Irganox 1076, Sumilizer GS, and the like are preferred from the viewpoint of the effect of imparting thermal stability to the resin. These may be used alone or in combination of two or more.

[0202] In addition, examples of the phosphorus-based antioxidant as the antioxidant include, but are not limited to, tris(2,4-di-t-butylphenyl)phosphite, bis(2,4-bis(1,1-dimethylethyl)-6-methylphenyl)ethyl ester phosphorous acid, tetrakis(2,4-di-t-butylphenyl)(1,1-biphenyl)-4,4'-diylbisphosphonite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-t-butyl-4-methyl phenyl)pentaerythritol diphosphite, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, tetrakis(2,4-t-butylphenyl)(1,1-biphenyl)-4,4'-diylbisphosphonite, di-t-butyl-m-cresyl-phosphonite, 4-[3-[(2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphepin)-6-yloxy]propyl]-2-methyl-6-tert-butylphenol, and the like.

[0203] Furthermore, a commercially available phosphorus-based antioxidant may be used as the phosphorus-based antioxidant. Examples of such commercially available phosphorus-based antioxidants include, but are not limited to, Irgafos 168 (Irgafos 168: tris(2,4-di-t-butylphenyl)phosphite, manufactured by BASF), Irgafos 12 (Irgafos 12: tris[2-[[2,4,8,10-tetra-t-butyldibenzo[d,f][1,3,2]dioxaphosphen-6-yl]oxy]ethyl]amine, manufactured by BASF), Irgafos 38 (Irgafos 38: bis(2,4-bis(1,1-dimethylethyl)-6-methylphenyl)ethyl ester phosphorous acid, manufactured by BASF), ADK STAB 329K (ADK STAB-229K, manufactured by ADEKA), ADK STAB PEP-36 (ADK STAB PEP-36, manufactured by ADEKA), ADK STAB PEP-36A, ADK STAB PEP-8, ADK STAB HP-10, ADK STAB HP-10, ADK STAB 2112, manufactured by ADEKA, ADK STAB 1178, manufactured by ADEKA, ADK STAB 1500, manufactured by ADEKA, Sandstab P-EPQ, manufactured by Clariant, Weston 618, manufactured by GE, Weston 619G, manufactured by GE, Ultranox 626, manufactured by GE, Sumilizer GP GP: 4-[3-[(2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphepin)-6-yloxy]propyl]-2-methyl-6-tert-butylphenol, manufactured by Sumitomo Chemical Co., Ltd.), HCA (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, manufactured by Sanko Co., Ltd.), and the like. Among these commercially available phosphorus-based antioxidants, from the viewpoint of the effect of imparting thermal stability to the resin and the effect of using them in combination with various other antioxidants, Irgafos 168, ADK STAB PEP-36, ADK STAB PEP-36A, ADK STAB HP-10, and ADK STAB 1178 are preferred, with ADK STAB PEP-36A and ADK STAB PEP-36 being particularly preferred. These phosphorus-based antioxidants may be used alone or in combination of two or more kinds.

[0204] In addition, examples of the sulfur-based antioxidant as the antioxidant include, but are not limited to, 2,4-bis(dodecylthiomethyl)-6-methylphenol (Irganox 1726, manufactured by BASF), 2,4-bis(octylthiomethyl)-6-methylphenol (Irganox 1520L, manufactured by BASF), 2,2-bis{[3-(dodecylthio)-1-oxopropoxy]methyl}propane-1 ,3-diylbis[3-dodecylthio]propionate] (ADEKA STAB AO-412S, manufactured by ADEKA Corporation), 2,2-bis{[3-(dodecylthio)-1-oxopropoxy]methyl}propane-1,3-diylbis[3-dodecylthio]propionate] (ChemiNox PLS, manufactured by Chemipro Chemical Co., Ltd.), and di(tridecyl) 3,3'-thiodipropionate (AO-503, manufactured by ADEKA Corporation). Among these commercially available sulfur antioxidants, ADK STAB AO-412S and Cheminox PLS are preferred from the viewpoints of the effect of imparting thermal stability to the resin, the effect of using them in combination with various antioxidants, and ease of handling. These sulfur-based antioxidants may be used alone or in combination of two or more kinds.

[0205] The content of the antioxidant may be any amount that provides the effect of improving thermal stability. If the content is excessive, problems such as bleeding out during processing may occur. Therefore, the content is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, even more preferably 1 part by mass or less, even more preferably 0.8 parts by mass or less, still more preferably 0.01 to 0.8 parts by mass, and particularly preferably 0.01 to 0.5 parts by mass, relative to 100 parts by mass of the methacrylic resin.

[0206] The content of the antioxidant may be any amount that provides the effect of improving thermal stability. If the content is excessive, problems such as bleeding out during processing may occur. Therefore, the content is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, still more preferably 0.8% by mass or less, still more preferably 0.01 to 0.8% by mass, and particularly preferably 0.01 to 0.5% by mass, relative to 100% by mass of the methacrylic resin.

[0207] The timing of adding the antioxidant is not particularly limited, and examples thereof include a method of adding the antioxidant to a monomer solution before polymerization and then initiating polymerization, a method of adding the antioxidant to a polymer solution after polymerization and mixing it and then subjecting it to a devolatilization step, a method of adding the antioxidant to a molten polymer after devolatilization and then mixing it and then pelletizing it, a method of adding the antioxidant when the pellets after devolatilization and pelletization are melt-extruded again, etc. Among these, from the viewpoint of preventing thermal deterioration and coloration in the devolatilization step, it is preferable to add the antioxidant to a polymer solution after polymerization and mix it, add it before the devolatilization step, and then subject it to the devolatilization step.

[0208] -Hindered amine light stabilizer- The resin composition constituting the molded body contained in the resin window member according to this embodiment can contain a hindered amine-based light stabilizer. The hindered amine light stabilizer is not particularly limited, but is preferably a compound containing three or more ring structures. Here, the ring structure is preferably at least one selected from the group consisting of an aromatic ring, an aliphatic ring, an aromatic heterocycle, and a non-aromatic heterocycle, and when one compound has two or more ring structures, they may be the same or different from each other. Examples of the hindered amine light stabilizer include, but are not limited to, bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butyl malonate, a mixture of bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidylsebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, N ,N'-Bis(2,2,6,6-tetramethyl-4-piperidyl)-N,N'-diformylhexamethylenediamine, polycondensation product of dibutylamine·1,3,5-triazine·N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl -4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, 1,2,2,6,6-pentamethyl-4-piperidiol and β,β,β',β'-tetramethyl-2,4,8,10-tetraoxaspiro[5 Examples of such compounds include reaction products of 2,2,6,6-tetramethyl-4-piperidiol and β,β,β',β'-tetramethyl-2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diethanol, reaction products of 2,2,6,6-tetramethyl-4-piperidiol and β,β,β',β'-tetramethyl-2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diethanol, bis(1-undecyloxy-2,2,6,6-tetramethylpiperidin-4-yl)carbonate, 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, and 2,2,6,6-tetramethyl-4-piperidyl methacrylate. Among these, bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, a polycondensate of dibutylamine·1,3,5-triazine·N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine, and poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], a reaction product of 1,2,2,6,6-pentamethyl-4-piperidiol and β,β,β',β'-tetramethyl-2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diethanol, and a reaction product of 2,2,6,6-tetramethyl-4-piperidiol and β,β,β',β'-tetramethyl-2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diethanol are preferred. The content of the hindered amine light stabilizer may be any amount that provides the effect of improving light stability. If the content is excessive, problems such as bleeding out during processing may occur. Therefore, the content is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, still more preferably 0.8% by mass or less, still more preferably 0.01 to 0.8% by mass, and particularly preferably 0.01 to 0.5% by mass, relative to 100% by mass of the methacrylic resin.

[0209] -UV absorbers- The resin composition constituting the molded body included in the resin window member according to this embodiment may contain an ultraviolet absorbing agent. The ultraviolet absorbent is not particularly limited, but is preferably an ultraviolet absorbent having a maximum absorption wavelength of 280 to 380 nm, and examples thereof include benzotriazole-based compounds, benzotriazine-based compounds, benzophenone-based compounds, oxybenzophenone-based compounds, benzoate-based compounds, phenol-based compounds, oxazole-based compounds, cyanoacrylate-based compounds, and benzoxazinone-based compounds. Benzotriazole compounds include 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol], 2-(3,5-di-tert-butyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(2H-benzotriazol-2-yl)-p-cresol, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2-benzotriazol-2-yl-4,6-di-tert-butylphenol, 2-[5-chloro(2H)-benzotriazol-2-yl]-4-methyl-6-t-butylphenol, 2-(2H-benzotriazol-2-yl)-4,6-di-t-butylphenol, 2-(2H-benzotriazol-2-yl)-4-(1,1 ,3,3-tetramethylbutyl)phenol, 2-(2H-benzotriazol-2-yl)-4-methyl-6-(3,4,5,6-tetrahydrophthalimidylmethyl)phenol, methyl 3-(3-(2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxyphenyl)propionate / polyethylene glycol 300 reaction product, 2-(2H-benzotriazol-2-yl)-6-(linear and side chain dodecyl)-4-methylphenol, 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy-C7-9 side chain and linear alkyl esters. Among these, benzotriazole-based compounds having a molecular weight of 400 or more are preferred, and examples of commercially available products include Kemisorb (registered trademark) 2792 (manufactured by Chemipro Chemicals), Adeka STAB (registered trademark) LA31 (manufactured by ADEKA Corporation), and Tinuvin (registered trademark) 234 (manufactured by BASF). Benzotriazine compounds include 2-mono(hydroxyphenyl)-1,3,5-triazine compounds, 2,4-bis(hydroxyphenyl)-1,3,5-triazine compounds, and 2,4,6-tris(hydroxyphenyl)-1,3,5-triazine compounds. Specific examples of the benzotriazine compounds include 2,4-diphenyl-6-(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-ethoxyphenyl)-1,3,5-triazine, and 2,4-diphenyl-(2-hydroxy-4-propoxyphenyl). )-1,3,5-triazine, 2,4-diphenyl-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-dodecyloxyphenyl)-1,3,5-triazine, 2,4 -diphenyl-6-(2-hydroxy-4-benzyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-butoxyethoxy)-1,3,5-triazine, 2,4-bis(2-hydroxy-4-butoxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3-5-triazine, 2,4,6-tris(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-ethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy -4-propoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-dodecyloxyphenyl)-1,3,5-triazine, 2,4,6-Tris(2-hydroxy-4-benzyloxyphenyl)-1,3,5-triazine, 2,4,6-Tris(2-hydroxy-4-ethoxyethoxyphenyl)-1,3,5-triazine, 2,4,6-Tris(2-hydroxy-4-butoxyethoxyphenyl)-1,3,5-triazine, 2,4,6-Tris(2-hydroxy-4-propoxyethoxyphenyl)-1,3,5-triazine, 2,4,6-Tris(2-hydroxy-4-methoxycarbonylpropyloxyphenyl)-1,3,5-triazine, 2,4,6-Tris(2-hydroxy-4-methoxycarbonylpropyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-ethoxycarbonylethyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-(1-(2-ethoxyhexyloxy)-1-oxopropan-2-yloxy)phenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-methoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-ethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-ethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4- propoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-butoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-butoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-hexyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-octyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-octyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-benzyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-ethoxyethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-butoxyethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-propoxyethoxyphenyl)-1,3,5-triazine, 2,4,Examples of the tris(2-hydroxy-3-methyl-4-methoxycarbonylpropyloxyphenyl)-1,3,5-triazine include 6-tris(2-hydroxy-3-methyl-4-ethoxycarbonylethyloxyphenyl)-1,3,5-triazine, and 2,4,6-tris(2-hydroxy-3-methyl-4-(1-(2-ethoxyhexyloxy)-1-oxopropan-2-yloxy)phenyl)-1,3,5-triazine. As the benzotriazine compound, commercially available products may be used, such as Kemisorb 102 (manufactured by Chemipro Chemicals), LA-F70 (manufactured by ADEKA Corporation), LA-46 (manufactured by ADEKA Corporation), TINUVIN 405 (manufactured by BASF), TINUVIN 460 (manufactured by BASF), TINUVIN 479 (manufactured by BASF), and TINUVIN 1577FF (manufactured by BASF). Among these, ultraviolet absorbers having a 2,4-bis(2,4-dimethylphenyl)-6-[2-hydroxy-4-(3-alkyloxy-2-hydroxypropyloxy)-5-α-cumylphenyl]-s-triazine skeleton (where "alkyloxy" refers to a long-chain alkyloxy group such as octyloxy, nonyloxy, decyloxy, etc.) are more preferably used because of their high compatibility with acrylic resins and excellent ultraviolet absorption properties.

[0210] As the ultraviolet absorber, from the viewpoints of compatibility with the resin and volatility upon heating, in particular, benzotriazole-based compounds and benzotriazine-based compounds having a molecular weight of 400 or more are preferred, and from the viewpoint of suppressing decomposition of the ultraviolet absorber itself due to heating during extrusion processing, benzotriazine-based compounds are particularly preferred.

[0211] The melting point (Tm) of the ultraviolet absorbent is preferably 80° C. or higher, more preferably 100° C. or higher, even more preferably 130° C. or higher, and even more preferably 160° C. or higher. The above-mentioned ultraviolet absorber preferably has a weight loss rate of 50% or less, more preferably 30% or less, even more preferably 15% or less, even more preferably 10% or less, and even more preferably 5% or less when heated from 23°C to 260°C at a rate of 20°C / min. These ultraviolet absorbents may be used alone or in combination of two or more. By using two types of ultraviolet absorbents having different structures in combination, ultraviolet rays in a wide wavelength range can be absorbed.

[0212] The content of the ultraviolet absorber is not particularly limited as long as it does not impair heat resistance, moist heat resistance, thermal stability, and moldability and exerts the effects of the present invention, but is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4 parts by mass, more preferably 0.25 to 3 parts by mass, and even more preferably 0.3 to 3 parts by mass, relative to 100 parts by mass of the methacrylic resin. When it is within this range, the balance between ultraviolet absorbing performance, moldability, etc. is excellent.

[0213] -Release agent- The resin composition constituting the molded body included in the resin window member according to the present embodiment may contain a mold release agent, which may include, but is not limited to, fatty acid esters, fatty acid amides, fatty acid metal salts, hydrocarbon-based lubricants, alcohol-based lubricants, polyalkylene glycols, carboxylate esters, and hydrocarbon paraffin-based mineral oils.

[0214] The fatty acid ester that can be used as the release agent is not particularly limited, and any of the conventionally known fatty acid esters can be used. Examples of fatty acid esters that can be used include ester compounds of fatty acids having 12 to 32 carbon atoms, such as lauric acid, palmitic acid, heptadecanoic acid, stearic acid, oleic acid, arachic acid, and behenic acid, with monohydric aliphatic alcohols, such as palmityl alcohol, stearyl alcohol, and behenyl alcohol, and polyhydric aliphatic alcohols, such as glycerin, pentaerythritol, dipentaerythritol, and sorbitan; and complex ester compounds of fatty acids, polybasic organic acids, and monohydric aliphatic alcohols or polyhydric aliphatic alcohols.

[0215] Examples of such fatty acid ester lubricants include cetyl palmitate, butyl stearate, stearyl stearate, stearyl citrate, glycerin monocaprylate, glycerin monocaprate, glycerin monolaurate, glycerin monopalmitate, glycerin dipalmitate, glycerin monostearate, glycerin distearate, glycerin tristearate, glycerin monooleate, glycerin dioleate, glycerin trioleate, glycerin monolinoleate, and the like. glycerin monobehenate, glycerin mono 12-hydroxystearate, glycerin di 12-hydroxystearate, glycerin tri 12-hydroxystearate, glycerin diacetomonostearate, glycerin citrate fatty acid ester, pentaerythritol adipic acid stearate, partially saponified montanic acid ester, pentaerythritol tetrastearate, dipentaerythritol hexastearate, and sorbitan tristearate. These fatty acid ester-based lubricants can be used alone or in combination of two or more. Examples of commercially available products include the Rikemal series, Poem series, Rikestar series, and Rikemaster series manufactured by Riken Vitamin Co., Ltd., and the Excel series, Leodor series, Exepar series, and Coconard series manufactured by Kao Corporation, and more specific examples include Rikemal S-100, Rikemal H-100, Poem V-100, Rikemal B-100, Rikemal HC-100, Rikemal S-200, Poem B-200, Rikestar EW-200, Rikestar EW-400, Excel S-95, and Leodor MS-50.

[0216] The fatty acid amide is also not particularly limited, and any of the conventionally known fatty acid amides can be used. Examples of fatty acid amides include saturated fatty acid amides such as lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide; unsaturated fatty acid amides such as oleic acid amide, erucic acid amide, and ricinoleic acid amide; substituted amides such as N-stearyl stearic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, and N-oleyl palmitic acid amide; methylol amides such as methylol stearic acid amide and methylol behenic acid amide; methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, and ethylene bisstearic acid amide (ethylene bis saturated fatty acid bisamides such as ethylene bisstearylamide, ethylene bisisostearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene bishydroxystearic acid amide, N,N'-distearyl adipamide, and N,N'-distearyl sebacic acid amide; unsaturated fatty acid bisamides such as ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipamide, and N,N'-dioleyl sebacic acid amide; and aromatic bisamides such as m-xylylene bisstearic acid amide and N,N'-distearyl isophthalic acid amide. These fatty acid amides can be used alone or in combination of two or more. Examples of commercially available products include the Diamid series (manufactured by Nippon Kasei Co., Ltd.), the Amide series (manufactured by Nippon Kasei Co., Ltd.), the Nikka Amide series (manufactured by Nippon Kasei Co., Ltd.), the Methylol Amide series, the Bis Amide series, the Slipax series (manufactured by Nippon Kasei Co., Ltd.), the Kaowax series (manufactured by Kao Corporation), the Fatty Acid Amide series (manufactured by Kao Corporation), and ethylene bis stearic acid amides (manufactured by Dainichi Chemical Industry Co., Ltd.).

[0217] The fatty acid metal salt refers to a metal salt of a higher fatty acid, and examples thereof include lithium stearate, magnesium stearate, calcium stearate, calcium laurate, calcium ricinoleate, strontium stearate, barium stearate, barium laurate, barium ricinoleate, zinc stearate, zinc laurate, zinc ricinoleate, zinc 2-ethylhexoate, lead stearate, dibasic lead stearate, lead naphthenate, calcium 12-hydroxystearate, and lithium 12-hydroxystearate. Of these, calcium stearate, magnesium stearate, and zinc stearate are particularly preferred because the resulting transparent resin composition has excellent processability and extremely excellent transparency. Examples of commercially available products include the SZ series, SC series, SM series, and SA series manufactured by Sakai Chemical Industry Co., Ltd. When the fatty acid metal salt is used, its content is preferably 0.2% by mass or less relative to 100% by mass of the resin composition, from the viewpoint of maintaining transparency.

[0218] The above-mentioned release agents may be used alone or in combination of two or more kinds.

[0219] The release agent to be used is preferably one having a decomposition onset temperature of 200° C. or higher. Here, the decomposition onset temperature can be measured based on the 1% mass loss temperature by TGA.

[0220] The content of the release agent may be an amount that can obtain the effect as a release agent, and if the content is excessive, problems such as bleed-out during processing and extrusion failure due to screw slippage may occur, so the content is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, even more preferably 0.8% by mass or less, still more preferably 0.01 to 0.8% by mass, and particularly preferably 0.01 to 0.5% by mass, relative to 100% by mass of the methacrylic resin. When the release agent is added in the amount within the above range, the decrease in transparency due to the addition of the release agent is suppressed, and release failure during injection molding tends to be suppressed, so this is preferable.

[0221] The content of the release agent may be an amount that can obtain the effect as a release agent, and if the content is excessive, problems such as bleed-out during processing and extrusion failure due to screw slippage may occur, so the content is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, even more preferably 1 part by mass or less, even more preferably 0.8 parts by mass or less, still more preferably 0.01 to 0.8 parts by mass, and particularly preferably 0.01 to 0.5 parts by mass, relative to 100 parts by mass of the methacrylic resin. When the amount is added in the above range, the decrease in transparency due to the addition of the release agent is suppressed, and release failure during injection molding tends to be suppressed.

[0222] -Other thermoplastic resins- The resin composition constituting the molded body contained in the resin window member of this embodiment may also contain thermoplastic resins other than methacrylic resins for the purpose of adjusting birefringence or improving flexibility without compromising the objectives of the present invention.

[0223] Examples of other thermoplastic resins include polyacrylates such as polybutyl acrylate; styrene-based polymers such as polystyrene, styrene-butyl acrylate copolymer, styrene-acrylonitrile copolymer, and acrylonitrile-butadiene-styrene block copolymer; and further, for example, acrylic rubber particles having a 3-4 layer structure described in JP-A-59-202213, JP-A-63-27516, JP-A-51-129449, JP-A-52-56150, etc.; rubbery polymers disclosed in JP-B-60-17406 and JP-A-8-245854; methacrylic rubber-containing graft copolymer particles obtained by multistage polymerization described in WO 2014-002491; and the like. Among these, from the viewpoint of obtaining good optical properties and mechanical properties, rubber-containing graft copolymer particles having a graft portion on their surface layer made of a composition compatible with styrene-acrylonitrile copolymers and methacrylic resins containing a structural unit (X) having a ring structure in the main chain are preferred.

[0224] The average particle size of the above-mentioned acrylic rubber particles, methacrylic rubber-containing graft copolymer particles, and rubber polymer is preferably 0.03 to 1 μm, and more preferably 0.05 to 0.5 μm, from the viewpoint of improving the impact strength and optical properties of the molded article obtained from the above composition.

[0225] The content of the other thermoplastic resin is preferably 0 to 50 parts by mass, and more preferably 0 to 25 parts by mass, based on 100 parts by mass of the methacrylic resin.

[0226] -Light absorber- The resin composition constituting the molded body contained in the resin window member according to this embodiment may contain two or more types of light absorbents that have different wavelengths that show a maximum absorbance in the wavelength range of 380 nm or more and 900 nm or less, as long as the effects of the present invention are not impaired. For example, a near-infrared absorbing dye that has a maximum absorbance in the near-infrared region of 700 nm or more and 900 nm or less and a visible light absorbent that has a maximum absorbance in the visible light region of 450 nm or more and less than 700 nm can be used in combination.

[0227] Examples of near-infrared absorbing dyes that absorb light with wavelengths in the near-infrared region include anthraquinone dyes and phthalocyanine dyes. Among them, anthraquinone dyes, which are near-infrared absorbing dyes, are preferred because they provide excellent transparency and weather resistance to the molded product. The near-infrared absorbing dyes may be used alone or in combination of two or more. Examples of such light absorbing agents include the SDO series manufactured by Arimoto Chemical Industry Co., Ltd., the EX Color (registered trademark) series manufactured by Nippon Shokubai Co., Ltd., and the KAYASORB (registered trademark) series manufactured by Nippon Kayaku Co., Ltd.

[0228] It is preferable to use one near infrared absorbing dye alone, and the content is 0.001 to 1 part by mass, preferably 0.01 to 0.5 parts by mass, relative to 100 parts by mass of the thermoplastic resin. If the content of the light absorber (A) is equal to or more than the lower limit, the molded article has excellent color selectivity for transmitted light, and if it is equal to or less than the upper limit, the molded article has excellent transmitted light intensity.

[0229] Examples of the light absorbing agent include dyes, and examples of the dyes include anthraquinone dyes, perinone dyes, methine dyes, and quinophthalone dyes. Among the light absorbing agents, anthraquinone dyes and perinone dyes are preferred because they provide excellent weather resistance to the molded body. One type may be used alone, or two or more types may be used in combination.

[0230] Examples of anthraquinone dyes include dyes having color indexes such as Solvent Blue 87, Solvent Blue 94, Solvent Blue 97, Solvent Green 3, Solvent Green 28, Solvent Red 52, Solvent Red 111, Disperse Red 22, Solvent Violet 13, and Solvent Violet 36. Examples of perinone dyes include dyes having a color index of Solvent Orange 60, Solvent Red 135, Solvent Red 179, and the like. Examples of methine dyes include dyes with color indexes such as Solvent Orange 107 and Solvent Yellow 179. Examples of quinophthalone dyes include dyes with color indexes such as Solvent Yellow 33, Disperse Yellow 54, and Disperse Yellow 160.

[0231] The resin composition contains at least one light absorbing agent (preferably the dye), and the content thereof is preferably 0.1 to 0.5 parts by mass, more preferably 0.15 to 0.35 parts by mass, relative to 100 parts by mass of the thermoplastic resin, as the total content of the light absorbing agents (preferably the dye). If the total content of the light absorbing agents (preferably the dye) is equal to or more than the lower limit, the molded article has excellent color selectivity for transmitted light, and if it is equal to or less than the upper limit, the molded article has excellent transmitted light intensity.

[0232] The content of each of the light absorbing agents (preferably the dyes) is preferably 0.01 to 0.45 parts by mass, more preferably 0.02 to 0.4 parts by mass, relative to 100 parts by mass of the thermoplastic resin. When the content of each of the light absorbing agents (preferably the dyes) is equal to or greater than the lower limit, the molded article has excellent color selectivity for transmitted light, and when the content is equal to or less than the upper limit, the molded article has excellent transmitted light intensity.

[0233] [Method of producing thermoplastic resin composition] The resin composition can be produced, for example, by mixing a thermoplastic resin (preferably the above-mentioned methacrylic resin) and two or more types of light absorbents that have different wavelengths that show the maximum absorbance in the wavelength range of 380 nm to 880 nm. A known method can be adopted as the mixing method, and for example, the resin composition is produced by mixing using a mixer such as a Henschel mixer, ribbon blender, Banbury mixer, or drum tumbler, and further kneading using a kneader such as a single-screw extruder, twin-screw extruder, or multi-screw extruder at a melt temperature of 200 to 300° C. for 5 to 60 minutes.

[0234] The method for producing the resin composition constituting the molded body included in the resin window member according to this embodiment is not particularly limited as long as a composition satisfying the above requirements can be obtained. For example, a method of kneading using a kneader such as an extruder, a heating roll, a kneader, a roller mixer, or a Banbury mixer can be mentioned. Among them, kneading using an extruder is preferred in terms of productivity. The kneading temperature may be in accordance with the preferred processing temperature of the polymer constituting the methacrylic resin or the other resin to be mixed, and is generally in the range of 140 to 300°C, preferably 180 to 280°C. In addition, it is preferable to provide a vent port in the extruder for the purpose of reducing volatile content.

[0235] Here, in the resin composition constituting the molded body contained in the resin window member of this embodiment, the amount of remaining solvent (residual solvent amount) is preferably less than 1000 ppm by mass, more preferably less than 800 ppm by mass, and even more preferably less than 700 ppm by mass. Here, the remaining solvent refers to the polymerization solvent (excluding alcohols) used during polymerization and the solvent used when redissolving and dissolving the resin obtained by polymerization. Specific examples of the polymerization solvent include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and isopropylbenzene; ketones such as methyl isobutyl ketone, butyl cellosolve, methyl ethyl ketone, and cyclohexanone; polar solvents such as dimethylformamide and 2-methylpyrrolidone; and the like. Examples of the solvent used for redissolution include toluene, methyl ethyl ketone, and methylene chloride.

[0236] The resin composition constituting the molded body contained in the resin window member of this embodiment preferably has a residual alcohol amount (residual alcohol content) of less than 500 ppm by mass, more preferably less than 400 ppm by mass, and even more preferably less than 350 ppm by mass. The remaining alcohol herein refers to an alcohol by-produced in the cyclization condensation reaction, and specific examples thereof include aliphatic alcohols such as methanol, ethanol, and isopropanol.

[0237] The amount of the remaining solvent and the amount of the remaining alcohol can be measured by gas chromatography.

[0238] Whichever method is selected, it is preferable to prepare the composition after reducing oxygen and water as much as possible. For example, the dissolved oxygen concentration in the polymerization solution in solution polymerization is preferably less than 300 ppm in the polymerization step, and in a preparation method using an extruder or the like, the oxygen concentration in the extruder is preferably less than 1% by volume, more preferably less than 0.8% by volume. The water content of the methacrylic resin is preferably adjusted to 1000 ppm by mass or less, more preferably 500 ppm by mass or less. Within these ranges, it is advantageous since it becomes relatively easy to prepare a composition that satisfies the requirements of the present invention.

[0239] -Glass transition temperature- The resin composition constituting the molded body contained in the resin window member according to this embodiment preferably has a glass transition temperature (Tg) of 105° C. or more and 160° C. or less, more preferably 110 to 155° C., even more preferably 115 to 150° C., and most preferably 120 to 150° C. The glass transition temperature can be measured by the midpoint method in accordance with JIS-K7121. The resin composition has a glass transition temperature of 115° or higher, which ensures heat resistance to the high temperature environment expected inside a vehicle and to heat generated by a computing chip that processes images (including video) captured by a camera. In addition, when the molded body is bonded to a housing or a near-infrared compatible polarizing element with an adhesive or pressure sensitive adhesive, high heat resistance is advantageous in terms of suppressing peeling caused by differences in dimensional changes. On the other hand, when the glass transition temperature (Tg) is 160° C. or lower, melt processing at extremely high temperatures is avoided, thermal decomposition of the resin, etc. is suppressed, and a good product can be obtained. From the viewpoint of further obtaining the above-mentioned effects, the glass transition temperature (Tg) is preferably 155° C. or lower, more preferably 150° C. or lower, and even more preferably 140° C. or lower. Furthermore, if the glass transition temperature exceeds 150°C, the mold temperature must be kept high in the injection molding step described below in order to reduce the birefringence of the molded body. However, this requires a long cooling time in order to suppress deformation such as sink marks when removing the molded body, lengthening the cycle time, and furthermore, distortion is likely to remain in the resin lens due to rapid cooling due to the temperature difference with room temperature, which is undesirable from the viewpoint of sufficiently reducing the birefringence of the molded body.

[0240] -Photoelastic coefficient CR- The absolute value |CR| of the photoelastic coefficient CR of the resin composition constituting the molded body included in the resin window member according to this embodiment is 10.0×10 -12 Pa -1 It is preferable that the ratio is 5.0×10 or less, and more preferable that the ratio is 5.0×10 -12 Pa -1 More preferably, it is 3.0×10 -12 Pa -1 More preferably, it is 1.0×10 -12 Pa -1The photoelastic coefficient is described in various documents (for example, see Chemical Review, No. 39, 1998 (published by the Academic Press Center)) and is defined by the following formulas (ia) and (ib). It can be seen that the closer the photoelastic coefficient CR value is to zero, the smaller the change in birefringence due to external force is. |CR|=|Δn| / σR (ia) |Δn|=|nx-ny| (ib) (In the formula, CR is the photoelastic coefficient, σR is the tensile stress, |Δn| is the absolute value of birefringence, nx is the refractive index in the stretching direction, and ny is the refractive index in the in-plane direction perpendicular to the stretching direction.) The absolute value |CR| of the photoelastic coefficient CR of the resin composition is 10.0×10 -12 Pa -1 By setting the photoelastic coefficient |CR| at 5.0×10 or less, it is possible to suppress the photoelastic birefringence caused by the stress generated when fixing or adhering the molded body to the housing and the dimensional change caused by the environmental change such as temperature to a low level, and therefore it is possible to obtain a resin window member capable of capturing a clear image (video). -12 Pa -1 , 3.0×10 -12 Pa -1 By doing so, it is possible to obtain a molded body having a sufficiently low birefringence even if the annealing step, which is a strain relaxation step after molding, is omitted.

[0241] -Molecular weight and molecular weight distribution- The resin composition constituting the molded body contained in the resin window member according to this embodiment has a weight average molecular weight (Mw) in terms of polymethyl methacrylate measured by gel permeation chromatography (GPC) preferably in the range of 80,000 to 170,000, more preferably in the range of 90,000 to 170,000, even more preferably in the range of 100,000 to 150,000, and still more preferably in the range of 110,000 to 150,000. When the weight average molecular weight (Mw) is in the above range, the balance between mechanical strength and fluidity is excellent.

[0242] The weight average molecular weight (Mw), number average molecular weight (Mn), and Z average molecular weight (Mz) of the resin composition can be measured using the following apparatus and conditions. Measurement equipment: Tosoh Corporation gel permeation chromatography (HLC-8320GPC) Measurement conditions: Columns: One TSKguardcolumn SuperH-H, two TSKgel SuperHM-M, and one TSKgel SuperH2500, connected in series. Column temperature: 40℃ Developing solvent: tetrahydrofuran, flow rate: 0.6 mL / min, 2,6-di-t-butyl-4-methylphenol (BHT) was added as an internal standard at 0.1 g / L. Detector: RI (differential refractometer) detector Detection sensitivity: 3.0mV / min Sample: 0.02 g of resin window material dissolved in 20 mL of tetrahydrofuran Injection volume: 10μL Standard sample for calibration curve: The following 10 types of polymethyl methacrylate (PMMA Calibration Kit MM-10, manufactured by Polymer Laboratories) with known monodisperse weight peak molecular weights and different molecular weights are used. Weight peak molecular weight (Mp) Standard sample 1 1,916,000 Standard sample 2 625,500 Standard sample 3 298,900 Standard sample 4 138,600 Standard sample 5 60,150 Standard sample 6 27,600 Standard sample 7 10,290 Standard sample 8 5,000 Standard sample 9 2,810 Standard sample 10 850 Under the above conditions, the RI detection intensity is measured versus the elution time of the resin window member. Based on the respective calibration curves obtained by measuring the standard samples for the calibration curves, the weight average molecular weight (Mw), number average molecular weight (Mn), and Z average molecular weight (Mz) of the resin window member are determined, and the molecular weight distributions (Mw / Mn) and (Mz / Mw) are determined using these values.

[0243] -Acid component amount- The resin composition constituting the molded body contained in the resin window member according to this embodiment can be measured by using the resin composition as a sample instead of the molded body of the resin window member in a measurement method using ion chromatography described in the Examples below. This measurement makes it possible to measure the content of acid components dissolved in the resin composition that can be liberated from the molded body, rather than the acid value due to the resin structure. The acid content is preferably 150 ppm or less, more preferably 100 ppm or less, even more preferably 50 ppm or less, and particularly preferably 20 ppm or less. By using such a molded body that does not contain an acid component, the adhesion of the adhesive surface and the adhesive surface can be well maintained even when it is used by bonding it to a housing or a polarizing element having a polarization separation performance in the near infrared region. Specifically, even after repeated condensation and drying or after a reliability test under a high temperature and high humidity environment, the acid component dissolved in the molded body does not dissolve into water or the like and does not affect the interface, so that problems such as contaminating the adhesive interface and the adhesive interface, lowering the quality of the image, and reducing the adhesion are unlikely to occur. Furthermore, when the polarizing element is referred to as a wire grid polarizer, the deterioration of the metal wire that constitutes the reflective surface related to the polarization separation described later can be suppressed.

[0244] -Saturated water absorption rate- The resin composition constituting the molded body contained in the resin window member according to this embodiment can have its saturated water absorption measured by the measurement method described in the Examples section below. The saturated water absorption is preferably in the range of 0.005% to 3%, more preferably in the range of 0.007% to 2.5%, and particularly preferably in the range of 0.01% to 2.0%. By forming a molded product using a resin composition in this range, it is possible to maintain good adhesion at the coat interface even when a treatment such as an anti-reflective coat or a hard coat is applied, and it is also possible to maintain a good appearance without peeling from the coat or cracking in the coat even after a high-temperature and high-humidity test.

[0245] -Melt Viscosity- In order to improve the transferability of the lens shape, it is preferable that the above methacrylic resin composition has a low viscosity and high fluidity in a state equivalent to the state at the time of injection. -1 In the melt viscosity, it is preferably 20 to 235 Pa·sec, more preferably 20 to 230 Pa·sec, even more preferably 30 to 180 Pa·sec, and particularly preferably 50 to 150 Pa·sec. If the melt viscosity is less than 20 Pa·sec, it is difficult to control the flow of the resin during injection, and the surface accuracy of the molded product (deviation from the design value or the standard curvature radius) is poor due to poor pressure retention, and problems such as deterioration of the surface accuracy due to sink marks on the lens after molding occur. On the other hand, if the melt viscosity is greater than 235 Pa·sec, the fluidity of the resin decreases, resulting in poor transferability of the lens shape, making molding extremely difficult, especially for thin lenses, and if the resin is forcibly pressed into the mold, the molded body sticks to the mold, causing chipping and cracking during demolding, and problems such as discoloration due to burning of the resin and burning foreign matter associated with troubleshooting. The melt viscosity is a value measured in accordance with JIS-K7199.

[0246] -Tensile breaking strain- The methacrylic resin composition preferably has a large tensile fracture strain (also called tensile elongation at break) in order to avoid process delays due to cracks or chips in the molded piece at the time of release due to sticking to the mold in injection molding, cracks in the gate, etc. The tensile fracture strain is 1.5% or more, preferably 2.0% or more, and more preferably 2.5% or more. The tensile breaking strain is a value measured in accordance with ISO527, and specifically, can be measured by the method described in the examples below.

[0247] - Bending strength - When the methacrylic resin composition used in this embodiment is used by adhering to a housing or laminating to an optical film, it expands or contracts due to heat or water absorption, and at this time, bending stress acts due to the difference in dimensional changes between the resin window member and the housing or optical film. This may cause cracks or breaks in the resin window member, especially when the molded body has a curvature or has uneven thickness. In order to prevent such defects, it is preferable that the bending strength is large. The bending strength is preferably 65 MPa or more, more preferably 75 MPa or more, and even more preferably 85 MPa or more. When the bending strength is in this range, the resin lens is less likely to crack even when the reflective polarizing element-attached lens is subjected to a reliability test. The upper limit of the bending strength is preferably 180 MPa or less, more preferably 160 MPa or less, and particularly preferably 130 MPa. It is difficult to achieve both heat resistance, low orientation birefringence, low photoelasticity and low birefringence, and bending strength, and a resin composition having a bending strength outside the above range is inferior in heat resistance and optical properties, leading to deterioration of the detection accuracy of the sensor. The bending strength is a value measured in accordance with ISO178, and specifically, it can be measured by the method described in the examples described later. For a method of bonding a WGF to a molded body having a curved surface, refer to JP 2022-165579 A. In particular, when a WGF is bonded to a curved surface, a resin substrate having low bending strength may suffer from cracks during a constant temperature and humidity test or a thermal cycle test. Therefore, it is desirable that the methacrylic resin composition be within the above-mentioned preferred range.

[0248] [Method of manufacturing molded body] The molded article included in the resin window member of this embodiment is obtained by molding the above-mentioned resin composition. As a manufacturing method for the molded article included in the resin window member for a near-infrared sensor of this embodiment, a molding method such as injection molding, compression molding, extrusion molding, etc. Among these, injection molding is preferred from the viewpoint of productivity.

[0249] Typically, injection molding consists of (1) an injection process in which resin is melted and the molten resin is filled into the cavity of a temperature-controlled mold; (2) a pressure holding process in which pressure is applied inside the cavity until the gate is sealed, and an amount of resin is injected equivalent to the amount of molten resin filled in the injection process that comes into contact with the mold and cools and shrinks; (3) a cooling process in which the molded product is held until the resin has cooled after the pressure holding process is released; and (4) the mold is opened and the cooled molded product is removed.

[0250] In this embodiment, the temperature setting from the tip to the center of the nozzle of the injection molding machine cylinder is, based on the glass transition temperature (Tg) of the methacrylic resin composition used, preferably in the range of Tg+120 to Tg+180°C, preferably in the range of Tg+100°C to Tg+160°C, and more preferably in the range of Tg+110°C to Tg+150°C. Here, the molding temperature refers to the controlled temperature of the band heater wound around the injection nozzle. By setting the temperature within the above range, the molten resin flows sufficiently, and molding is possible in a state where deterioration due to thermal decomposition of the resin is suppressed. The higher the molding temperature, the higher the fluidity of the resin and the less likely it is that orientation birefringence will occur. However, at high temperatures, the thermal decomposition of the resin will have a negative effect on the color tone, transmittance, and haze, and gas will be generated during injection molding. The generated gas will fill the mold, and the gas pushed into the uneven parts during resin filling will not be discharged, hindering the filling of the resin and causing a decrease in the mold transfer rate. The molding temperature should be selected appropriately while observing the state of the molded body.

[0251] The mold temperature is preferably in the range of Tg-70°C to Tg, and more preferably in the range of Tg-50°C to Tg-20°C, based on the glass transition temperature (Tg) of the resin composition. By raising the mold temperature to a temperature close to Tg, the birefringence of the molded product can be reduced. On the other hand, the resin will tend to stick to the mold, which can lead to deterioration of the lens surface precision and process delays due to chipping of the resin or cracks in the gate caused by sticking. Therefore, the temperature should be selected appropriately.

[0252] The injection speed can be appropriately selected depending on the thickness and dimensions of the molded article to be obtained, and can be appropriately selected, for example, from the range of 2 to 1000 mm / sec. The pressure for holding can be appropriately selected depending on the shape of the molded body to be obtained, and can be appropriately selected, for example, within the range of 30 to 120 MPa. The pressure for holding the pressure referred to here is the pressure maintained by a screw for further feeding the molten resin from the gate after the molten resin has been filled.

[0253] In addition, an annealing step may be performed in order to relax residual stress caused by injection molding and reduce the phase difference of the molded product. The annealing temperature is preferably in the range of Tg-50°C to Tg, and more preferably in the range of Tg-30°C to Tg-10°C, based on the glass transition temperature (Tg) of the resin composition.

[0254] The surface of the resin window member of this embodiment may be further subjected to a surface functionalization treatment such as a hard coat treatment, an anti-reflection treatment, a mirror treatment, the provision of a retardation layer, a transparent conductive treatment, an electromagnetic wave shielding treatment, a gas barrier treatment, etc. The thickness of these functional layers is not particularly limited, but is usually in the range of 0.01 to 10 μm.

[0255] The hard coat layer to be applied to the surface of the resin window member can be formed, for example, by applying a coating liquid prepared by dissolving or dispersing an acrylate such as a silicone-based curable resin, an organic polymer composite inorganic microparticle-containing curable resin, urethane acrylate, epoxy acrylate, or polyfunctional acrylate, and a photopolymerization initiator in an organic solvent onto a film or sheet obtained from the above-mentioned resin composition by a conventionally known coating method, drying, and photocuring. In addition, before applying the hard coat layer, in order to improve adhesion, for example, a method of forming an easy-adhesion layer, a primer layer, an anchor layer, or the like containing inorganic fine particles in its composition and then forming the hard coat layer can be used.

[0256] The antiglare layer to be applied to the surface of the resin window member is formed by making fine particles of silica, melamine resin, acrylic resin, etc. into an ink, applying it onto other functional layers using a conventionally known application method, and curing it with heat or light.

[0257] Examples of anti-reflection layers to be applied to the surface of a resin window member include thin films of inorganic materials such as metal oxides, fluorides, silicides, borides, nitrides, and sulfides, and single or multiple layers of resins with different refractive indexes such as acrylic resins and fluororesins. Additionally, a thin layer containing composite fine particles of an inorganic compound and an organic compound can also be used.

[0258] A mirror or half mirror may be applied to the surface of the resin window member. Any suitable mirror or half mirror may be used, for example, by coating a thin layer of metal (e.g., silver or aluminum) on the resin window member. Alternatively, a mirror may be formed by depositing a thin dielectric coating on the surface of the resin window member. A combination of a metal coating method and a dielectric coating method may also be used. The reflectance and transmittance of light can be controlled by the thickness and number of layers to be coated, and by using a dielectric deposition technique, it is possible to design the material to reflect only light of a specific wavelength.

[0259] The resin window member for a near-infrared sensor of this embodiment is preferably used in combination with a polarizing element having polarization separation ability in the near-infrared region and a near-infrared sensor, and is preferably installed between the subject and the near-infrared sensor.

[0260] [Protective cover] The protective cover of the present embodiment includes the resin window member for the near-infrared sensor of the present embodiment described above. Examples of the protective cover include a protective cover for a headset housing, a protective cover for a LiDAR for distance measurement, and a protective cover for a LiDAR for face recognition.

[0261] [Near infrared sensor] The near-infrared sensor of the present embodiment includes at least the resin window member for near-infrared sensors of the present embodiment described above. The near-infrared sensor of the present embodiment preferably includes a polarizing element, and may include at least a resin window member for near-infrared sensors that does not include a polarizing element and a polarizing element, or may include a resin window member for near-infrared sensors that includes a polarizing element. The near-infrared sensor of this embodiment further includes an object and a light receiving unit, and it is preferable that the resin window member for the near-infrared sensor of this embodiment is provided between the object and the light receiving unit (FIG. 3). The near-infrared sensor of this embodiment includes the above-mentioned resin window member for the near-infrared sensor of this embodiment, a polarizing element having polarization separation ability, and a near-infrared camera, and it is preferable that the resin window member for the near-infrared sensor is provided between the object and the near-infrared camera. EXAMPLES

[0262] The present invention will be described below with reference to specific examples and comparative examples, but is not limited to these.

[0263] (Evaluation of resin composition properties) The methods for measuring the properties of the resin composition will be described below.

[0264] <Measurement of tensile breaking strain> Pellets of the resin composition produced in the production example described later were dried at 80 to 100°C for 24 hours, and injection molded using an injection molding machine (Toshiba Machine Co., Ltd., EX-100SX) according to JIS-K6717 to produce an ISO3167 A-type dumbbell test piece with a thickness of 4.0 mm. A tensile test was performed on this test piece using a low-load universal material testing machine (Instron) according to ISO527 at a measurement temperature of 23°C and a crosshead speed of 5 mm / min. Five measurements were performed, and the chuck elongation at tensile break was measured, and the average value was calculated as the tensile break strain (%).

[0265] <Measurement of bending strength> Pellets of the resin composition produced in the production example described later were dried at 80 to 100 ° C for 24 hours, and injection molded according to JIS-K6717 using an injection molding machine (Toshiba Machine Co., Ltd., EX-100SX) to produce an ISO3167 A-type dumbbell test piece with a thickness of 4.0 mm. The center of this test piece was cut out to prepare a molded piece with a length of 80 mm, a width of 10 mm, and a thickness of 4.0 mm. A bending test was performed using a low-load universal material testing machine (Instron Co., Ltd.) according to ISO178 at a measurement temperature of 23 ° C, a test speed of 2 mm / min, and a support distance of 64 mm. Five measurements were performed, and the average value was calculated as the bending strength (MPa).

[0266] (Evaluation of properties of resin composition and resin window member including molded article made of resin composition) Hereinafter, methods for measuring the properties of the resin composition and the resin window member including a molded article made from the resin composition will be described.

[0267] <Structural unit analysis> Each structural unit of the molded part of the resin window member produced in the production examples and production comparative examples described below is, unless otherwise specified, 1 H-NMR measurement and 13 By C-NMR measurement, each structural unit of the resin and the resin composition was identified, and the amount of each structural unit was calculated. 1 H-NMR measurement and 13 The measurement conditions for C-NMR measurement are as follows: Measuring equipment: JNM-ECZ400S manufactured by JEOL Ltd. Measurement solvent: CDCl 3 , or d6-DMSO ·Measurement temperature: 40℃ When the ring structure contained in the main chain of the methacrylic resin was a lactone ring structure, it was confirmed by the methods described in JP-A-2001-151814 and JP-A-2007-297620.

[0268] <Molecular weight and molecular weight distribution> The weight average molecular weight (Mw), number average molecular weight (Mn), and Z average molecular weight (Mz) of the cut-out molded portions of the resin window members produced in the manufacturing examples and comparative manufacturing examples described below were measured using the following equipment and conditions. Measurement equipment: Tosoh Corporation gel permeation chromatography (HLC-8320GPC) Measurement conditions: Columns: One TSKguardcolumn SuperH-H, two TSKgel SuperHM-M, and one TSKgel SuperH2500 were connected in series. Column temperature: 40℃ The developing solvent was tetrahydrofuran, the flow rate was 0.6 mL / min, and 2,6-di-t-butyl-4-methylphenol (BHT) was added as an internal standard at 0.1 g / L. Detector: RI (differential refractometer) detector Detection sensitivity: 3.0mV / min Sample: 0.02 g of methacrylic resin composition dissolved in 20 mL of tetrahydrofuran Injection volume: 10μL Standard sample for calibration curve: The following ten types of polymethyl methacrylate (PMMA Calibration Kit MM-10, manufactured by Polymer Laboratories) with known monodisperse weight peak molecular weights and different molecular weights were used. Weight peak molecular weight (Mp) Standard sample 1 1,916,000 Standard sample 2 625,500 Standard sample 3 298,900 Standard sample 4 138,600 Standard sample 5 60,150 Standard sample 6 27,600 Standard sample 7 10,290 Standard sample 8 5,000 Standard sample 9 2,810 Standard sample 10 850 Under the above conditions, the RI detection intensity was measured versus the elution time of the methacrylic resin composition. Based on each calibration curve obtained by measuring the standard samples for the calibration curve, the weight average molecular weight (Mw), number average molecular weight (Mn), and Z average molecular weight (Mz) of the methacrylic resin composition were determined, and the molecular weight distributions (Mw / Mn) and (Mz / Mw) were determined using these values.

[0269] <Measurement of glass transition temperature> The glass transition temperature (Tg) (°C) was measured in accordance with JIS-K7121. First, four test pieces (four locations), each weighing approximately 10 mg, were prepared as samples by cutting out the molded portions of the resin window members produced in the manufacturing examples and comparative manufacturing examples described below, after conditioning them under standard conditions (23°C, 50% RH) (left at 23°C for one week). Next, a differential scanning calorimeter (Diamond DSC manufactured by PerkinElmer Japan Co., Ltd.) was used under the condition of a nitrogen gas flow rate of 25 mL / min. Here, the temperature was raised from room temperature (23°C) to 200°C at 10°C / min (first heating), and the sample was held at 200°C for 5 minutes to completely melt the sample. The temperature was then lowered from 200°C to 40°C at 10°C / min, and held at 40°C for 5 minutes. Furthermore, the sample was heated again under the above heating conditions (second heating). Among the DSC curves drawn during this period, the intersection point between the stepwise change part curve during the second heating and the straight line equidistant in the vertical direction from each baseline extension line (the glass transition temperature of the methacrylic resin composition was measured in accordance with JIS-K7121. A differential scanning calorimeter (Perkin-Lumer Japan Co., Ltd., DSC8000) was used under the condition of a nitrogen gas flow rate of 25 mL / min. Here, the sample was heated from room temperature (23°C) to 200°C (first heating) at 10°C / min, held at 200°C for 5 minutes to completely melt the sample, then cooled from 200°C to 40°C at 10°C / min, held at 40°C for 5 minutes, and heated again under the above heating conditions (second heating). Among the DSC curves drawn during this period, the intersection point (midpoint glass transition temperature) between the step-like change part curve during the second heating and a straight line equidistant in the vertical direction from each baseline extension line was measured as the glass transition temperature (Tg) (°C). Four points were measured per sample, and the arithmetic average (rounded off to the nearest whole number) of the four points was taken as the measured value.

[0270] <Measurement of absolute value of photoelastic coefficient> A molded portion of the resin window member manufactured in the manufacturing example and manufacturing comparative example described below was cut out and pressed into a film using a vacuum compression molding machine to prepare a measurement sample. Specific sample preparation conditions were as follows: using a vacuum compression molding machine (Shinto Metal Industries, SFV-30 model), preheating at 260°C and reduced pressure (approximately 10 kPa) for 10 minutes, the cut-out molded part was compressed at 260°C and approximately 10 MPa for 5 minutes, and after the reduced pressure and press pressure were released, it was transferred to a cooling compression molding machine and cooled and solidified. The obtained pressed film was aged for 24 hours or more in a constant temperature and humidity room adjusted to 23°C and humidity 60%, and then a test specimen (approximately 150 μm thick and 6 mm wide) for measurement was cut out. The photoelastic coefficient CR (Pa-1) was measured using a birefringence measuring device described in detail in Polymer Engineering and Science 1999, 39, 2349-2357. The film-like test piece was placed on a film tensioning device (manufactured by Imoto Manufacturing Co., Ltd.) similarly installed in a constant temperature and humidity chamber so that the distance between the chucks was 50 mm. Next, a birefringence measuring device (manufactured by Otsuka Electronics, RETS-100) was placed so that the laser light path of the device was located at the center of the film, and the birefringence of the test piece was measured while applying a tensile stress at a strain rate of 50% / min (distance between chucks: 50 mm, chuck movement speed: 5 mm / min). From the relationship between the measured birefringence (Δn) and the tensile stress (σR), the slope of the line was calculated by least squares approximation, and the photoelastic coefficient (CR) (Pa -1 ) was calculated using data for the tensile stress range of 2.5MPa≦σR≦10MPa. CR=Δn / σR Here, the birefringence (Δn) has the value shown below. Δn=nx-ny (nx: refractive index in the stretching direction, ny: refractive index in the in-plane direction perpendicular to the stretching direction)

[0271] <Analysis of acid content> 0.25 g of a cut-out molded portion of the resin window member manufactured in the manufacturing examples and comparative manufacturing examples described below was dissolved in 5 g of chloroform (chloroform solution concentration of sample: 4.8 wt%). The resulting solution was added to a screw tube bottle containing 5 ml of pure water and mixed with a vortex to re-precipitate the resin. Next, the mixture was shaken for 5 minutes in a shaker and then allowed to stand to separate into an organic phase and an aqueous phase. The amount of acid components was analyzed from the aqueous layer obtained by liquid-liquid extraction. The eluted acid components were quantified using a TSKgel SuperIC-AP ion chromatograph (Tosoh Corporation, IC-2001). F (fluoride), acetic acid, formic acid, methacrylic acid, Cl (chloride), and SO 4 For the quantification of anions such as sulfuric acid and maleic acid, the quantification was performed using standard specimens for which standard specimens were easily available. Several unidentified components were confirmed at retention times before and after Cl, but for those whose identification and standard specimens were difficult to obtain, the area values ​​for the retention times before Cl were calculated as quantified values ​​converted to formic acid, and the retention times after Cl were calculated as quantified values ​​converted to maleic acid. Note that when calculating the above quantification, the area values ​​of the acid components detected in the aqueous phase when liquid-liquid extracted with 5 g of chloroform and 5 ml of water were subtracted in advance. The concentration relative to the sample (μg / g: ppm) was calculated using the following formula (6). Concentration relative to sample [ppm] = (Concentration of measured solution [mg / L] - Operating blank concentration [mg / L]) × Amount of pure water used [ml] ÷ Weight of dissolved compact [g] (6) In addition, the raw materials used in the Production Examples and Production Comparative Examples described later also have low miscibility with water, such as xylene and toluene, and the raw materials are dissolved in a solvent in which they are soluble, and then the amount of acid components can be similarly analyzed from the aqueous layer obtained by liquid-liquid extraction using pure water.

[0272] <Measurement of saturated water absorption rate> Plates with sides of 10 to 100 mm and thicknesses of 1 to 3 mm were cut out from the cut-out molded portions of the resin window members produced in the production examples and production comparative examples described below. When the molded portion was small, a plate of the same size was produced by press molding using the cut-out portion of the molded portion and used as the sample. The obtained plate-shaped molded pieces were dried in accordance with JIS-7209, and then immersed in pure water (distilled water) at 23°C. Every 24 hours, the molded pieces were taken out and weighed. The measurements were repeated until the weight stabilized, and the saturated water absorption was calculated.

[0273] <Melt viscosity> Under conditions conforming to JIS-K7199, a twin capillary rheometer (manufactured by ROSAND) was used at a temperature of 270°C and a shear rate of 1000 sec -1 The melt viscosity (Pa sec) of the resin composition was measured using a capillary die with a diameter of 1 mm. The molded body portion of the resin window member produced in the Production Examples and Production Comparative Examples described below was finely cut and used as a sample, which was filled into a cylinder and used for the measurement.

[0274] <Retardation of resin window material (850 nm)> The molded body contained in the resin window member obtained in the examples and comparative examples was used to measure the surface distribution of the lens phase difference from the optical axis direction at a wavelength of 850 nm using a birefringence evaluation system WPA-200-NIR manufactured by Photonic Lattice, Inc. In the examples of the examples and comparative examples, a rectangular area of ​​58 mm x 43 mm was designated as the effective surface of the resin window member, and the average absolute value of the phase difference (nm) was obtained (Figure 5). The above-mentioned resin window member was placed on a horizontal plane, and a light beam parallel to the direction of gravity was irradiated from vertically above the resin window member to obtain a rectangular area of ​​58 mm x 43 mm, which was the effective surface. The projected area of ​​the rectangular area was 58 mm x 43 mm. The projected area of ​​the entire resin window member was 25 cm. 2 The projected area of ​​the 58 mm × 43 mm rectangle was 92% of the projected area of ​​the entire resin window member, which was 100%. In Comparative Examples 1 to 4, the absolute value of the in-plane retardation at a wavelength of 850 nm exceeds 20 nm in almost all regions. No matter how the measurement region is selected, the region in which the average absolute value of the in-plane retardation at a wavelength of 850 nm is less than 20 nm is continuous over a projected area of ​​5 cm. 2 In Comparative Examples 1 and 3, the area in which the absolute value of the in-plane retardation at a wavelength of 850 nm was less than 20 nm on average did not account for 50% or more of the projected area (100%) of the entire resin window member. If the sample size is small, the area must be at least 5 cm2. 2 The average value (nm) of the absolute value of the phase difference can be obtained by including the area of ​​the resin window member having a projected area of ​​5 cm 2 If the surface area is less than 50%, the average value (nm) of the absolute values ​​of the retardation in an area including 50% of the surface area can be obtained.

[0275] <Difference between phase difference of resin window material (810 nm) and phase difference of resin window material (850 nm)> The average value (nm) of the absolute value of the in-plane retardation at a wavelength of 810 nm was calculated in the same manner as above, except that the wavelength in <Retardation of resin window member (850 nm)> was 810 nm. Then, the difference from the average value of the absolute value of the in-plane retardation at a wavelength of 850 nm described above was calculated, and the absolute value was calculated. In Comparative Examples 1 to 4, in which there was no region in which the absolute value of the in-plane retardation at a wavelength of 850 nm was less than 20 nm on average, a rectangle of 58 mm×43 mm was used as the measurement region. In Examples 1 to 11, in all regions in which the absolute value of the in-plane retardation at a wavelength of 850 nm was less than 20 nm on average, the difference between the average value of the in-plane retardation at a wavelength of 810 nm and the average value of the in-plane retardation at a wavelength of 850 nm was the value shown in Table 1.

[0276] <Spectral transmittance of resin window material> The resin window members obtained in the examples and comparative examples were used as samples. When the resin window member could not be placed on the sample stage of the measuring device, the transmittance (%) of the resin window member was measured every 5 nm using an ultraviolet-visible-near infrared spectrophotometer (Shimadzu Corporation, UV3100PC) with a slit width set to 2 nm for wavelengths below 720 nm and 20 nm for wavelengths above 720 nm, with the light source passing through the main surface of the resin window member and passing in the thickness direction. The average of the transmittances in the range of 380 to 660 nm was taken as the visible light transmittance (%), and the average of the transmittances in the range of 800 to 1000 nm was taken as the near infrared transmittance (%).

[0277] <Measurement of visible light transmittance of molded body> A plate with a side length of 40 mm × 40 mm and a thickness of 2 mm was cut out from the cut-out molded portion of the resin window member manufactured in the manufacturing examples and manufacturing comparative examples described below. When the molded portion was small, a plate of the same size was produced by press molding using the cut-out portion of the molded portion and used as the sample. The transmittance (%) of the obtained molded article was measured at 5 nm intervals in the wavelength range of 380 to 660 nm using an ultraviolet-visible-near infrared spectrophotometer (Shimadzu Corporation, UV3100PC) with a slit width of 2 nm for wavelengths below 720 nm, with the light source passing through the main surface of the resin window member and through a thickness of 2 mmt. The average of the transmittance in the range of 380 to 660 nm was taken as the visible light transmittance (%) of the molded article.

[0278] <Rockwell hardness measurement> Samples were prepared by cutting the gates of the resin window members manufactured in the manufacturing examples and comparative manufacturing examples described below, leaving areas of 45.0 mm and 60.0 mm as shown in Figure 5. After checking that each resin window member had no sink marks or warping, six sheets were stacked together to obtain a sample with a thickness of 6 mm or more. In accordance with JIS K7202-2, the Rockwell hardness was measured on the M scale using a hardness tester (Akashi Seisakusho Co., Ltd., ARK-F3000). In addition, when the sample had a curved surface, a rectangular shape with one side longer than 3 cm was cut from the thickest part and milled to make the thickness uniform. Several pieces were stacked and measured to make the thickness 6 mm or more. Measurements were performed at five or more points to obtain the value.

[0279] <Evaluation using a near-infrared camera> The contrast of near-infrared images was evaluated using the resin window members obtained in the examples and comparative examples. As shown in Fig. 4, in order to evaluate the characteristics required for a resin window material for a near-infrared sensor (cutting out strong specular reflected light and noise light, acquiring clear images and data), a simulation device based on the principle of a driver monitor was created in a dark room. In this simulation device, a visible light cut filter 521 (manufactured by NEEWER, IR850) that cuts out light less than 850 nm was placed in front of an LED light source 51 (manufactured by UniqueFire, IR LED light) with a collimating lens that emits light of 850 nm, and then a wire grid polarizing element 531 (manufactured by Asahi Kasei, registered trademark WGF, HC12U) with an adhesive layer attached to a 2 mm thick glass plate 541 was positioned so as to transmit S-wave light (polarized perpendicular to the incident surface), forming a light source unit that irradiates a subject 56 with S-wave infrared light. An adhesive layer of a wire grid polarizing element 532 (manufactured by Asahi Kasei Corporation, registered trademark WGF, HC12U) was attached to one side of the resin window member (molded body) 57 obtained in the Examples and Comparative Examples. This was used as a reflective polarizing element-attached transparent resin window member 58, and an imaging unit was constructed in which the reflective polarizing element 432 was placed in front of a near-infrared camera 59 capable of capturing images of near-infrared light so that P-wave light could pass through, and the transparent resin plate 57 was placed so that it faced the subject 56 side. As subject 56, a glass plate 542 (manufactured by AS ONE, made of soda glass, Φ50 mm) was placed on the light source unit side, and subject 55 with characters measuring 7 mm on a side printed thereon was placed on the opposite side (back side) of glass plate 542 from the light source unit. In the above configuration, the subject was irradiated with near-infrared light from the light source unit, and an image of the subject was taken through the reflective polarizing element-attached transparent resin window member 58. At this time, the contrast was evaluated according to the following criteria. ◎ (Excellent): Strong lighting is almost entirely blocked, contrast is good, and characters can be clearly identified. Good: Strong lighting is cut out, and characters can be identified with good contrast. △ (poor): The lighting is strong and the contrast is poor, but the characters are distinguishable. × (Very poor): The lighting is strong, the image is overexposed, and the characters are unidentifiable.

[0280] <Dimensional change after high temperature and humidity test> The durability of the resin window members obtained in the examples and comparative examples in a constant temperature and humidity environment was evaluated. A constant temperature and humidity chamber (PL-4KP, manufactured by ESPEC) was set to an environment of 85°C and 85% RH, and after the specified conditions were reached, the resin window member was placed in the device in an upright state using the molded piece propping jig shown in Figure 7 (if it was not propped up, there was a risk that the surface would be scratched and the haze would worsen). After 1000 hours had passed in an environment of 85°C and 85% RH, the resin window member was taken out, and the vertical and horizontal lengths of the surface of the resin window member excluding the gate portion were measured with a vernier caliper. The direction in which the resin flows from the gate into the flat area (MD: Machine Direction) was defined as the vertical direction, and the direction perpendicular to that was defined as the horizontal direction (TD: Transverse Direction). The length of one piece was divided into four equal parts, and measurements were taken at a total of four points, and the average value was used as the measured value. (MD dimensional change) = (average value of 4 MD lengths after test) ÷ (average value of 4 MD lengths in the initial state) (TD dimensional change) = (average value of 4 TD lengths after test) ÷ (average value of 4 TD lengths in the initial state)

[0281] <Initial near-infrared haze measurement> Samples were prepared by cutting the gate portions of the resin window members manufactured in the manufacturing examples and comparative manufacturing examples described below, leaving areas of 45.0 mm and 60.0 mm as shown in FIG. An integrating sphere attachment ISR-1503 was installed on a UV-Vis-NIR spectrophotometer (Shimadzu Corporation, UV3100PC) to measure the transmittance of the near infrared region from 800 to 1000 nm without placing a sample. A standard white plate was placed at the opening of the integrating sphere in both the direction in which the measurement light enters the integrating sphere and the direction in which the reference light enters the integrating sphere, and the transmittance τ1 including the diffused light was measured (condition (1)). The standard white plate was not placed only at the opening of the integrating sphere in the direction in which the measurement light enters the integrating sphere, and the diffuse transmittance τ3 of the blank was measured by allowing the parallel transmitted light to pass through the integrating sphere (condition (2)). Next, the resin window members obtained in the examples and comparative examples were placed in front of the opening of the integrating sphere where the measurement light was incident, and the transmittance τ2 was measured in the same manner as in the above condition (1). Furthermore, the diffuse transmittance τ4 was measured in the same manner as in the above condition (2). Then, the haze (%) in the near infrared region was calculated using the following formula. Haze in the near infrared region (%) = {(τ4 ÷ τ2) - (τ3 ÷ τ1)} × 100

[0282] <Haze measurement and deformation evaluation after high-temperature aging test> The durability of the resin window members obtained in the examples and comparative examples was evaluated in a high-temperature aging test. The temperature inside the oven was set to 110°C, and after reaching the specified conditions, the resin window member was placed in the device in an upright position using the molded piece propping jig shown in Figure 8 (if it was not propped up, there is a risk that the surface would be scratched and the haze would worsen). It was placed in an oven set to 110°C, and after 2000 hours, it was taken out and the near-infrared haze of the resin window member was measured in the same manner as in <Initial near-infrared haze measurement> above, and the presence or absence of deformation was evaluated from the appearance. The presence or absence of deformation was evaluated according to the following criteria: In Comparative Example 2, the gate portion was deformed. 〇(Excellent): No deformation △(Good): Slightly deformed × (defective): Severely deformed and unusable

[0283] [Raw materials] The raw materials used in the examples and comparative examples described later are shown below.

[0284] [[Monomers that make up methacrylic resins]] Methyl methacrylate (MMA): Asahi Kasei Corporation N-Phenylmaleimide (PMI): Nippon Shokubai Co., Ltd. N-Cyclohexylmaleimide (CMI): Nippon Shokubai Co., Ltd. Styrene: Fujifilm Wako Pure Chemical Industries, Ltd. α-Methylstyrene: Fujifilm Wako Pure Chemical Industries, Ltd. Methyl 2-(hydroxymethyl)acrylate (MHMA): Combi-Blocks

[0285] [[Organic solvents]] Meta-xylene (mXy): Manufactured by Mitsubishi Gas Chemical Co., Ltd. Methyl isobutyrate: manufactured by Kanto Chemical Co., Ltd. Toluene: Fujifilm Wako Pure Chemical Industries, Ltd.

[0286] [[Polymerization initiator]] 1,1-Di(t-butylperoxy)cyclohexane: NOF Corporation t-Amylperoxy-2-ethylhexanoate: "Luperox 575" manufactured by Arkema Yoshitomi Co., Ltd. t-Amyl peroxyisononanoate: Arkema Yoshitomi Co., Ltd.

[0287] [[Chain transfer agent]] n-Octyl mercaptan: Chevron Phillips Chemical Company n-Dodecyl mercaptan: Fujifilm Wako Pure Chemical Industries, Ltd.

[0288] [[Additives]] Pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]: BASF "Irganox 1010" Tris(2,4-di-t-butylphenyl)phosphite: BASF "Irgafos168" Rikemal H-100: manufactured by Riken Vitamin Co., Ltd. - Adeka STAB 2112: Manufactured by ADEKA Corporation Stearyl phosphate / distearyl phosphate mixture: Sakai Chemical Industry Co., Ltd. - Adeka STAB PEP-36: Manufactured by ADEKA Corporation Octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate: BASF "Irganox 1076" Monomethylamine: Mitsubishi Gas Chemical Company, Inc. Dimethyl carbonate: Fujifilm Wako Pure Chemical Industries, Ltd. Triethylamine: Fujifilm Wako Pure Chemical Industries, Ltd. Carbon black #45: Mitsubishi Chemical

[0289] Of the above raw materials, N-phenylmaleimide and N-cyclohexylmaleimide were stored in a warehouse where the temperature was adjusted to be within the range of 20 to 30°C from the time of delivery, and the raw materials were used within 3 months of the delivery date. Before use, the raw material was dissolved in meta-xylene, and liquid-liquid extraction was performed using pure water, after which the amount of acid components was quantified using the aqueous layer. A large amount of maleic acid and fumaric acid was confirmed from N-phenylmaleimide, with a total of 950 ppm of acid components. On the other hand, a total of 110 ppm of acid components was confirmed from N-cyclohexylmaleimide. If the amount of maleic acid exceeds 1000 ppm, the maleimide was washed with water and dehydrated by the method described in JP 2021-92767 A, purified, and then used for the production of methacrylic resin.

[0290] Synthesis Example 1 [Methacrylic resin composition A] 318.7 kg of methyl methacrylate (hereinafter referred to as MMA), 35.5 g of N-phenylmaleimide (hereinafter referred to as PMI), 63.7 kg of N-cyclohexylmaleimide (hereinafter referred to as CMI), 0.341 kg of n-octyl mercaptan as a chain transfer agent, and 225.1 kg of meta-xylene (hereinafter referred to as mXy) ​​were weighed out and added to a 1.25 m 3 The mixture was added to a reactor and stirred to obtain a mixed monomer solution. Next, 116.9 kg of mXy was weighed and added to Tank 1 to prepare additional solvent. Furthermore, 104.5 kg of MMA and 85.5 kg of mXy were weighed into Tank 2 and stirred to obtain an MMA solution for further addition. The liquid in the reactor was bubbled with nitrogen at a rate of 30 L / min for 1 hour, and tank 1 and tank 2 were each bubbled with nitrogen at a rate of 10 L / min for 30 minutes to remove dissolved oxygen. Then, steam was blown into the jacket to raise the solution temperature in the reactor to 125°C, and polymerization was started by adding a polymerization initiator solution in which 0.457 kg of 1,1-di(t-butylperoxy)cyclohexane was dissolved in 2.67 kg of mXy at a rate of 1 kg / hour while stirring at 50 rpm. During polymerization, the solution temperature in the reactor was controlled at 125±2°C by temperature control using the jacket. 30 minutes after the start of polymerization, the addition rate of the polymerization initiator solution was reduced to 0.25 kg / hour, and mXy was further added from tank 1 at 29.24 kg / hour for 3.5 hours. Then, 4 hours after the initiation of polymerization, the addition rate of the polymerization initiator solution was increased to 0.75 kg / hour, and additional MMA solution was added from Tank 2 at 95 kg / hour for 2 hours. Further, 6 hours after the start of polymerization, the addition rate of the polymerization initiator solution was reduced to 0.25 kg / hour, and 7 hours after the start of polymerization, the addition was stopped. After 8 hours had elapsed since the start of polymerization, a polymerization solution containing a methacrylic resin was obtained, to which were added 0.261 kg of Irganox1010 and 0.784 kg of Irgafos168 as antioxidants, and 0.784 kg of Rikemal H-100 as a mold release agent. Next, the obtained polymerization solution was fed to a concentrator consisting of a tubular heat exchanger and a vaporizer previously heated to 250°C, and devolatilization was carried out. The degree of vacuum in the vaporizer was set to 10 to 15 Torr. The resin flowing down the vaporizer was discharged by a screw pump, extruded from a strand die, cooled with water, and pelletized to obtain a methacrylic resin composition A having an N-substituted maleimide structural unit. The obtained pellets had a Tg of 133°C, a melt viscosity of 131 Pa·sec, a tensile breaking strain of 1.7%, and a bending strength of 66 MPa.

[0291] Synthesis Example 2 [Methacrylic resin composition B] A monomer composition consisting of 75.000 mol% MMA, 24.998 mol% styrene, and 0.002 mol% t-amylperoxy-2-ethylhexanoate as a polymerization initiator was continuously fed at 1 kg / h to a 10L complete mixing tank with a helical ribbon blade, and continuous polymerization was performed at an average residence time of 2.5 hours and a polymerization temperature of 150°C. The liquid was continuously withdrawn from the bottom so that the liquid level in the polymerization tank was constant, and was fed to a concentrating device consisting of a tubular heat exchanger and a vaporization tank for devolatilization. The vacuum degree of the vaporization tank was set to 10 to 15 Torr. The resin that flowed down the vaporization tank was discharged with a screw pump, extruded from a strand die, pelletized after water cooling, and introduced into a desolvation device to obtain a pellet-shaped methyl methacrylate-styrene copolymer. This copolymer was dissolved in methyl isobutyrate to prepare a 10% by mass methyl isobutyrate solution. 500 parts by mass of this 10% by mass methyl isobutyrate solution of the copolymer and 1 part by mass of 10% by mass Pd / C (manufactured by NE Chemcat Corporation) as a hydrogenation catalyst were charged into a 1000 mL autoclave apparatus, and the mixture was maintained at 200°C and a hydrogen pressure of 9 MPa for 15 hours to hydrogenate the aromatic double bonds of the styrene moiety of the copolymer. The hydrogenation catalyst was removed by a filter, and 0.04 parts by mass of Rikemar H-100 was added to and mixed with the polymer solution, and the mixture was fed to a concentrator consisting of a tubular heat exchanger and a vaporization tank for devolatilization. The vacuum degree of the vaporization tank was set to 10 to 15 Torr. The resin that flowed down the vaporization tank was discharged by a gear pump, extruded from a strand die, cooled with water, and pelletized to obtain a methacrylic resin composition B. The obtained pellets had a Tg of 119°C, a melt viscosity of 83 Pa·sec, a tensile breaking strain of 2.9%, and a bending strength of 95 MPa.

[0292] Synthesis Example 3 [Methacrylic resin composition C] A 30 L reaction vessel equipped with a stirring device equipped with a paddle blade, a temperature sensor, a cooling tube, and a nitrogen inlet tube was charged with 2.25 kg of methyl methacrylate, 0.32 kg of methyl 2-(hydroxymethyl)acrylate, 0.024 kg of styrene, 0.025 parts by mass of n-dodecyl mercaptan as a chain transfer agent relative to 100 parts by mass of the total amount of all monomers finally charged into the reaction vessel, 0.025 parts of ADK STAB 2112, and 5.39 kg of toluene, and the mixture was heated to 105°C with stirring while passing nitrogen through. As an initial initiator, a solution consisting of 0.20 kg of toluene and 0.014 kg of t-amyl peroxy isononanoate was dropped into the polymerization tank over 10 minutes, while polymerization was carried out at 105°C to 110°C. 10 minutes later, a solution consisting of 0.26 kg of toluene and 0.017 kg of t-amyl peroxy isononanoate was dropped over 3 hours, and simultaneously with the addition of this initiator solution, a solution consisting of 2.75 kg of methyl methacrylate, 0.40 kg of methyl 2-(hydroxymethyl)acrylate, and 0.24 kg of styrene was dropped over 3 hours, while polymerization was carried out at a polymerization temperature of 105°C to 110°C, and maturation was carried out for another 2 hours. To the obtained polymer solution, a mixed solution of 4.5 g of a stearyl phosphate / distearyl phosphate mixture and 72 g of toluene was added, and a cyclization condensation reaction was carried out for 1.5 hours at 90 to 110° C. After that, 0.10 parts by mass of Rikemal H-100 was added per 100 parts by mass of the total amount of all monomers finally charged in the reaction vessel, and the mixture was stirred and mixed. The obtained polymerization liquid was subjected to a cyclocondensation reaction and devolatilization treatment using a φ42 mm devolatilization extruder equipped with four front vents and one back vent at a barrel temperature of 220° C., 120 rpm, and 5 kg / hour in terms of resin amount, to obtain pellets of methacrylic resin composition C. The obtained pellets had a Tg of 127°C, a melt viscosity of 72 Pa·sec, a tensile breaking strain of 2.2%, and a bending strength of 98 MPa.

[0293] Synthesis Example 4 [Methacrylic resin composition D] According to the method for producing copolymer (A) described in the section [Examples] of JP 2003-231785 A, MS resin (copolymer of MMA and α-methylstyrene) was polymerized. The mass ratio of MMA and styrene charged in the autoclave was changed, and when the total monomer weight during polymerization was 100 parts by mass, 0.15 parts by mass of Rikemal H-100 was added and polymerization was performed to obtain a precursor resin (MMA:α-methylstyrene=88% by mass:12% by mass). A 40mm screw diameter co-rotating twin screw extruder was used, the extruder cylinder temperature was 275°C, the screw rotation speed was 150 rpm, and the MS resin obtained by the above polymerization was fed from the hopper at 20 kg / hour, while nitrogen was flowed into the extruder at a flow rate of 200 mL / min. After the resin was melted and filled by the kneading block, 2.2 parts by mass of monomethylamine was injected from the nozzle per 100 parts by mass of raw resin to carry out the imidization reaction. A reverse flight was inserted at the end of the reaction zone (before the vent port) to fill the zone with resin. The by-products and excess monomethylamine after the reaction were removed by reducing the pressure at the vent port to 30 Torr. The resin that came out as strands from the die installed at the extruder outlet was cooled in a water tank and then pelletized with a pelletizer to obtain an imide resin. Next, a 40mm screw diameter co-rotating twin screw extruder was used, the extruder cylinder temperature was set to 255°C, and the screw rotation speed was set to 150 rpm. The obtained imide resin was fed at 20 kg / hr, and the resin was melted and filled by a kneading block. Then, a mixed solution of dimethyl carbonate and triethylamine was injected from a nozzle as an esterification agent to reduce the carboxylic acid group in the resin. Dimethyl carbonate was 2.6 parts by mass and triethylamine was 0.2 parts by mass per 100 parts by mass of imide resin. The by-products and excess dimethyl carbonate after the reaction were removed by reducing the pressure at the vent port to 30 Torr. The resin that came out as strands from the die installed at the extruder outlet was cooled in a water tank and then pelletized with a pelletizer to obtain a methacrylic resin composition D having a glutarimide structure. The obtained pellets had a Tg of 134°C, a melt viscosity of 172 Pa·sec, a tensile breaking strain of 5.1%, and a bending strength of 95 MPa.

[0294] Synthesis Example 5 [Methacrylic resin composition E] 298.5 kg of MMA, 37.0 kg of PMI, 104.5 kg of CMI, 0.23 kg of n-octyl mercaptan as a chain transfer agent, and 247.0 kg of mXy were weighed out and placed in a 1.25m 3 The mixture was added to a reactor and stirred to obtain a mixed monomer solution. Then 123.0 kg of mXy was weighed and added to Tank 1. Furthermore, 110.0 kg of MMA and 80.0 kg of mXy were weighed and stirred in tank 2 to prepare a monomer solution for additional addition. The liquid in the reactor was bubbled with nitrogen at a rate of 30 L / min for 1 hour, and tank 1 and tank 2 were each bubbled with nitrogen at a rate of 10 L / min for 30 minutes to remove dissolved oxygen. Thereafter, steam was blown into the jacket to raise the solution temperature in the reactor to 124°C, and while stirring at 50 rpm, a polymerization initiator solution prepared by dissolving 0.35 kg of 1,1-di(t-butylperoxy)cyclohexane in 4.652 kg of mXy was added at a rate of 1 kg / hour to initiate polymerization, and mXy was added from Tank 1 at a rate of 30.75 kg / hour for 4 hours. During the polymerization, the solution temperature in the reactor was controlled at 124±2° C. by temperature regulation using a jacket. Then, between 4 hours and 6 hours later, the monomer solution containing MMA was added from Tank 2 at a rate of 95 kg / hour. Furthermore, the addition rate of the polymerization initiator solution was reduced to 0.25 kg / hour 0.5 hour after the start of polymerization, to 0.75 kg / hour after 4 hours, and to 0.5 kg / hour after 6 hours. Seven hours after the start of polymerization, the addition of the polymerization initiator solution was stopped and the polymerization was continued for a further 3 hours to obtain a polymerization solution containing a methacrylic resin having a ring structural unit in its main chain. To this polymerization solution, 0.83 kg of Adeka STAB PEP-36, 0.28 kg of Irgafos 168, 0.44 kg of Irganox 1076, and 1.10 kg of Rikemal H-100 were added under stirring. Next, the obtained polymerization solution was fed to a concentrator consisting of a tubular heat exchanger and a vaporizer tank preheated to 260°C to carry out devolatilization. The degree of vacuum in the vaporizer tank was set to 10 to 15 Torr. The resin flowing down the vaporizer tank was discharged by a screw pump, extruded from a strand die, cooled with water, and pelletized to obtain a methacrylic resin F having an N-substituted maleimide structural unit. The obtained pellets had a Tg of 146°C, a melt viscosity of 210 Pa·sec, a tensile breaking strain of 3.9%, and a flexural strength of 59 MPa.

[0295] Synthesis Example 6 [Methacrylic resin composition F] Except for changing the amount of n-octyl mercaptan, which is a chain transfer agent, to 0.708 kg, polymerization was carried out in the same manner as in Synthesis Example 1 to obtain a methacrylic resin composition E. The acid component amounts of PMI and CMI were 5100 ppm for PMI and 230 ppm for CMI. The obtained pellets had a Tg of 132°C, a melt viscosity of 102 Pa·sec, a tensile breaking strain of 1.2%, and a bending strength of 68 MPa.

[0296] Synthesis Example 7 [Methacrylic resin composition G] A 40mm screw diameter co-rotating twin screw extruder was used, the extruder cylinder temperature was 275°C, the screw rotation speed was 150 rpm, and polymethyl methacrylate with a weight average molecular weight of 10,8000 containing 0.1 parts by mass of Rikemar H-100 was fed from the hopper at a rate of 20 kg / hour when the total mass of the polymer was 100 parts by mass, and nitrogen was flowed into the extruder at a flow rate of 200 mL / min. After the resin was melted and filled by the kneading block, 1.8 parts by mass of monomethylamine was injected from the nozzle per 100 parts by mass of the raw resin, and an imidization reaction was carried out. A reverse flight was inserted at the end of the reaction zone (before the vent port) to fill the resin. The by-products and excess monomethylamine after the reaction were removed by reducing the pressure at the vent port to 50 Torr. The resin that came out as strands from the die installed at the extruder outlet was cooled in a water tank and then pelletized with a pelletizer to obtain an imide resin. Next, a 40mm screw diameter co-rotating twin screw extruder was used, the extruder cylinder temperature was set to 255°C, and the screw rotation speed was set to 150 rpm. The obtained imide resin was fed at 20 kg / hr, and the resin was melted and filled by a kneading block. Then, a mixed solution of dimethyl carbonate and triethylamine was injected from a nozzle as an esterification agent to reduce the carboxylic acid group in the resin. Dimethyl carbonate was 3.2 parts by mass and triethylamine was 0.8 parts by mass per 100 parts by mass of imide resin. The by-products and excess dimethyl carbonate after the reaction were removed by reducing the pressure at the vent port to 50 Torr. The resin that came out as strands from the die installed at the extruder outlet was cooled in a water tank and then pelletized with a pelletizer to obtain a methacrylic resin composition G having a glutarimide structure. The resulting pellets had a Tg of 122°C, a melt viscosity of 158 Pa·sec, a tensile breaking strain of 7.9%, and a bending strength of 127 MPa. Other properties are summarized in the table below.

[0297] Synthesis Example 8 [Methacrylic resin composition H] A 30 L reaction kettle equipped with a stirring device equipped with a paddle blade, a temperature sensor, a cooling tube, and a nitrogen inlet tube was charged with 2.25 kg of methyl methacrylate, 1.25 kg of methyl 2-(hydroxymethyl)acrylate, 0.025 parts by mass of n-dodecyl mercaptan as a chain transfer agent relative to 100 parts by mass of the total amount of all monomers, 0.025 parts of ADK STAB 2112, and 6.25 kg of toluene, and the mixture was heated to 105°C with stirring while passing nitrogen through. While refluxing, 0.05 parts by mass of t-amyl peroxy isononanoate was added to the polymerization tank relative to 100 parts by mass of the total amount of all monomers, and 0.1 parts by mass of t-amyl peroxy isononanoate was further added dropwise over 2 hours while polymerization was carried out under reflux at a polymerization temperature of 105 to 110°C, and the polymerization reaction was further carried out for 6 hours. To the obtained polymer solution, 6.3 g of a stearyl phosphate / distearyl phosphate mixture was added, and a cyclization condensation reaction was carried out for 5 hours at 90 to 110° C. Then, 0.15 parts by mass of Rikemal H-100 was added per 100 parts by mass of the total amount of all monomers, and the mixture was stirred and mixed. The resulting polymerization liquid was subjected to a cyclocondensation reaction and devolatilization treatment using a φ42 mm devolatilization extruder equipped with four front vents and one back vent at 120 rpm at a resin amount of 2.2 kg / hour to obtain pellets of methacrylic resin composition H. The resulting pellets had a Tg of 133°C, a melt viscosity of 165 Pa·sec, a tensile breaking strain of 3.2%, and a bending strength of 71 MPa. Other properties are summarized in the table below.

[0298] Synthesis Example 9 [Methacrylic resin composition I] When preparing the mixed monomer solution to be initially charged into the reactor, 318.7 kg of MMA, 81.0 g of PMI, 35 kg of CMI, 0.30 kg of n-octyl mercaptan as a chain transfer agent, and 225.1 kg of mXy were weighed and stirred to obtain a mixed monomer solution. Except for this, polymerization was carried out in the same manner as in Synthesis Example 1, to obtain a methacrylic resin composition I. The obtained pellets had a Tg of 141°C, a melt viscosity of 230 Pa·sec, a tensile breaking strain of 2.1%, and a bending strength of 75 MPa.

[0299] Synthesis Example 10 [Methacrylic resin composition J] The methacrylic resin composition A obtained in Synthesis Example 1 was used as 100 parts by weight, and 0.1 parts by weight of carbon black (carbon black #45, manufactured by Mitsubishi Chemical Corporation) was mixed using a Henschel mixer (model name "SMV-20", manufactured by Kawata Corporation), and then the mixture was kneaded using a twin-screw extruder (model name "PCM45", manufactured by Ikegai Corporation) at a melt temperature of 260°C to obtain pellets of a thermoplastic resin composition. The obtained pellets had a Tg of 133°C, a melt viscosity of 127 Pa·sec, a tensile fracture strain of 1.6%, and a flexural strength of 60 MPa.

[0300] Example 1 [Molding of resin window components] Injection molding was performed using an injection molding machine (AUTO SHOT C Series MODEL 15A, manufactured by FANUC) using the methacrylic resin composition A obtained in Synthesis Example 1. The injection molding was performed using a flat mold having a fan gate and dimensions of 1 mm thick × 60 mm wide × 45 mm long as shown in FIG. First, the cylinder temperature was set to Tg+135°C of the resin composition to be used, the mold temperature was set to Tg-35°C of the resin composition to be used, the injection screw speed was set to 40mm / s, and the holding pressure was set to 0kgf / cm. 2 By changing the injection pressure and performing injection molding, the minimum injection pressure (short shot point, SSP) at which the resin is completely filled in the mold was obtained. Next, the injection pressure was set to SSP + 50kgf / cm 2 The resin window member according to Example 1 was obtained by injection molding under the conditions set at: The obtained flat molded piece was subjected to in-plane retardation distribution measurement at a wavelength of 850 nm using a birefringence evaluation system WPA-200-NIR (manufactured by Photonic Lattice). The in-plane retardation distribution measurement was performed by observing an area of ​​58 mm width × 43 mm length in the center of the flat plate from above, and the average absolute value of the in-plane retardation (Re) within the area was calculated as an index for evaluation. Other evaluation results are shown in Table 1. The amount of acid components in the molded product of Example 1 was 6 ppm.

[0301] Example 2 Using the methacrylic resin composition A obtained in Synthesis Example 1, injection molding was carried out in a flat plate mold having a thickness of 1 mm×width of 60 mm×length of 45 mm in the same manner as in Example 1. The obtained flat molded piece was cut off and polished, leaving a flat area of ​​60 mm in width and 45 mm in length. Next, 100 parts by mass of a solvent-based ink (MIX-HF ink, manufactured by Teikoku Ink Mfg. Co., Ltd.), 3 parts by mass of a hardener (210 hardener, manufactured by Teikoku Ink Mfg. Co., Ltd.), and 15 parts by mass of a solvent (C-002 solvent, manufactured by Teikoku Ink Mfg. Co., Ltd.) were mixed to prepare a black IR transmissive ink. The prepared ink was applied to the flat area of ​​the molded piece by screen printing using a T-300 mesh (linearity 0.030 mm). The coated molded piece was placed in an oven set at 80° C. for 30 minutes to dry and cure. The evaluation results of the obtained resin window members are shown in Table 1. The amount of acid components in the molded product of Example 2 was 6 ppm.

[0302] Example 3 A resin window member was obtained in the same manner as in Example 1, except for using the methacrylic resin composition B obtained in Synthesis Example 2. The evaluation results are shown in Table 1. In the high-temperature aging test, slight deformation was observed. The amount of acid components in the molded product of Example 3 was 20 ppm.

[0303] Example 4 A resin window member was obtained in the same manner as in Example 1, except for using the methacrylic resin composition C obtained in Synthesis Example 3. The evaluation results are shown in Table 1. The amount of acid components in the molded product of Example 4 was 38 ppm.

[0304] Example 5 A resin window member was obtained in the same manner as in Example 1, except for using the methacrylic resin composition D obtained in Synthesis Example 4. The evaluation results are shown in Table 1. The amount of acid components in the molded product of Example 5 was 65 ppm.

[0305] Example 6 A resin window member was obtained in the same manner as in Example 1, except for using the methacrylic resin composition E obtained in Synthesis Example 5. The evaluation results are shown in Table 1. The amount of acid components in the molded product of Example 6 was 25 ppm.

[0306] Example 7 A resin window member was obtained in the same manner as in Example 1, except for using the methacrylic resin composition F obtained in Synthesis Example 6. The evaluation results are shown in Table 1. The amount of acid components in the molded product of Example 7 was 120 ppm.

[0307] Example 8 A resin window member was obtained in the same manner as in Example 1, except for using the methacrylic resin composition G obtained in Synthesis Example 7. The evaluation results are shown in Table 1. The amount of acid components in the molded product of Example 8 was 107 ppm.

[0308] Example 9 Injection molding was performed using the methacrylic resin composition A obtained in Synthesis Example 1 with an injection molding machine (SE250EV-A-HD, manufactured by Sumitomo Heavy Industries, Ltd.) The mold used was a mold having a thickness of 3 mm and a width of 450 mm, with a fan gate of width 50 mm as shown in Fig. 6, and a shape that assumed a meter panel having a curved surface with a concave shape of a radius of curvature of 800 mm as viewed from above when the subject side is the upper surface. First, the cylinder temperature was set to Tg+135°C of the resin composition used, the mold temperature was set to Tg-23°C of the resin composition used, the injection screw speed was set to 40 mm / s, the first stage holding pressure was set to 60 MPa for 3 seconds, and then the second stage holding pressure was set to 35 MPa for 3 seconds to relax internal stress, and injection molding was performed to obtain the resin window member of Example 9. The amount of acid components in the molded product of Example 9 was 7 ppm.

[0309] In <Evaluation using a near-infrared camera>, the resin window member of Example 9 was used to serve as both glass plate 541 to which wire grid polarizer 531 is attached and resin plate 57 to which wire grid polarizer 532 is attached, the transmission axis of which is perpendicular to that of wire grid polarizer 531, and the evaluation was performed.

[0310] In other evaluations, the outer periphery of the effective surface of the resin window component, measuring 90 mm x 30 mm as the projection surface for the area where the near-infrared sensor is mounted, was cut out using an ultrasonic cutter and used as the measurement sample (including the effective surface). Note that, for the Rockwell hardness measurement, samples cut out to 50 mm x 30 mm were milled to a thickness of 2 mm to prepare multiple samples and perform the measurement. The in-plane retardation distribution was measured at a wavelength of 850 nm using a Photonic Lattice birefringence evaluation system WPA-200-NIR. The in-plane retardation distribution measurement was performed by observing a 90 mm x 30 mm area as a projection surface from above, and the average value of the absolute value of the in-plane retardation (Re) within the area was calculated as an evaluation index. The average absolute value of the in-plane retardation at 850 nm was 2.3 nm, and the average absolute value of the in-plane retardation when similarly measured at 810 nm was 1.9 nm, with the absolute value of the difference being 0.4 nm. Other evaluation results are shown in Table 1. The overall projected area of ​​the resin window member of Example 9 is 470 cm 2 The projected area of ​​the 90 mm × 30 mm rectangle was 5.7% of the projected area of ​​the entire resin window member, which was 100%.

[0311] Example 10 The methacrylic resin composition I obtained in Synthesis Example 9 was used and injection molding was performed using an injection molding machine (SE250EV-A-HD, manufactured by Sumitomo Heavy Industries, Ltd.). A mold having a cavity of 100 mm square x 2 mm thick was used to obtain a molded piece. The cylinder temperature was set to Tg+135°C of the resin composition used, the mold temperature was set to Tg-35°C of the resin composition used, the injection screw speed was 30 mm / s, and the holding pressure was 0 kgf / cm. 2By changing the injection pressure and performing injection molding, the minimum injection pressure (short shot point, SSP) at which the resin is completely filled in the mold was obtained. Next, the injection pressure was set to SSP + 50kgf / cm 2 A molded piece was obtained by injection molding under the setting of The gate portion of the obtained flat plate molded piece was cut off and polished, leaving a flat plate region of 100 mm square. Next, 100 parts by mass of a solvent-based ink (MIX-HF ink, manufactured by Teikoku Ink Mfg. Co., Ltd.), 3 parts by mass of a hardener (210 hardener, manufactured by Teikoku Ink Mfg. Co., Ltd.), and 15 parts by mass of a solvent (C-002 solvent, manufactured by Teikoku Ink Mfg. Co., Ltd.) were mixed to prepare a black IR transmissive ink. The prepared ink was applied to the flat area of ​​the molded piece by screen printing using a T-300 mesh (linearity 0.030 mm). The coated molded piece was placed in an oven set at 80° C. for 30 minutes to dry and cure. The evaluation results of the obtained resin window members are shown in Table 1. The amount of acid components in the molded product of Example 10 was 18 ppm.

[0312] In other evaluations, the area of ​​the resin window member on which the near-infrared sensor is mounted is used as the effective projection surface of 95 mm x 95 mm. The in-plane retardation distribution was measured at a wavelength of 850 nm using a Photonic Lattice birefringence evaluation system WPA-200-NIR. The in-plane retardation distribution measurement was performed by observing an area of ​​95 mm x 95 mm as the projection surface from above, and the average value of the absolute value of the in-plane retardation (Re) within the area was calculated as an index for evaluation. The average absolute value of the in-plane retardation at 850 nm was 13 nm. Other evaluation results are shown in Table 1. The overall projected area of ​​the resin window member of Example 10 is 100 cm 2 The projected area of ​​the 95 mm×95 mm rectangle was 90.3% of the projected area of ​​the entire resin window member, which was 100%.

[0313] Example 11 The methacrylic resin composition C obtained in Synthesis Example 3 was used and injection molding was performed with an injection molding machine (SE250EV-A-HD, manufactured by Sumitomo Heavy Industries, Ltd.). A mold having a cavity of 100 mm square x 2 mm thick was used to obtain a molded piece. The cylinder temperature was set to Tg+130°C of the resin composition used, the mold temperature was set to Tg-35°C of the resin composition used, the injection screw speed was 30 mm / s, and the holding pressure was 0 kgf / cm. 2 By changing the injection pressure and performing injection molding, the minimum injection pressure (short shot point, SSP) at which the resin is completely filled in the mold was obtained. Next, the injection pressure was set to SSP + 50kgf / cm 2 A molded piece was obtained by injection molding under the setting of The gate portion of the obtained flat plate molded piece was cut off and polished, leaving a flat plate region of 100 mm square. Next, 100 parts by mass of a solvent-based ink (MIX-HF ink, manufactured by Teikoku Ink Mfg. Co., Ltd.), 3 parts by mass of a hardener (210 hardener, manufactured by Teikoku Ink Mfg. Co., Ltd.), and 15 parts by mass of a solvent (C-002 solvent, manufactured by Teikoku Ink Mfg. Co., Ltd.) were mixed to prepare a black IR transmissive ink. The prepared ink was applied to the flat area of ​​the molded piece by screen printing using a T-300 mesh (linearity 0.030 mm). The coated molded piece was placed in an oven set at 80° C. for 30 minutes to dry and cure. The evaluation results of the obtained resin window members are shown in Table 1. The amount of acid components in the molded product of Example 11 was 40 ppm.

[0314] In other evaluations, the area of ​​the resin window member on which the near-infrared sensor is mounted is used as the effective projection surface of 95 mm x 95 mm. The in-plane retardation distribution was measured at a wavelength of 850 nm using a Photonic Lattice birefringence evaluation system WPA-200-NIR. The in-plane retardation distribution measurement was performed by observing an area of ​​95 mm x 95 mm as the projection surface from above, and the average value of the absolute value of the in-plane retardation (Re) within the area was calculated as an index for evaluation. The average absolute value of the in-plane retardation at 850 nm was 13 nm. Other evaluation results are shown in Table 1. The overall projected area of ​​the resin window member of Example 11 is 100 cm 2 The projected area of ​​the 95 mm×95 mm rectangle was 90.3% of the projected area of ​​the entire resin window member, which was 100%.

[0315] Comparative Example 1 A resin window member was obtained in the same manner as in Example 1, except that SD Polyca 303-15 (a polycarbonate resin having a Tg of 140° C., manufactured by Sumika Polycarbonate Co., Ltd.) was used as the resin composition. The evaluation results are shown in Table 1.

[0316] Comparative Example 2 A resin window member was obtained in the same manner as in Example 1, except that 80NH (methacrylic resin manufactured by Asahi Kasei Corporation, with a Tg of 112° C., a melt viscosity of 105 Pa sec, and a tensile breaking strain of 4.6%) was used as the resin composition. The evaluation results are shown in Table 1. The amount of acid components in the molded product of Comparative Example 2 was 12 ppm.

[0317] Comparative Example 3 A resin window member was obtained in the same manner as in Example 1, except that the resin composition used was methacrylic resin composition H. The evaluation results are shown in Table 1. The amount of acid components in the molded product of Comparative Example 3 was 58 ppm.

[0318] Comparative Example 4 A molded article was obtained in the same manner as in Example 1, except for using the methacrylic resin composition J obtained in Synthesis Example 10. The evaluation results are shown in Table 1.

[0319] With WGF (registered trademark, manufactured by Asahi Kasei Corporation) laminated to the resin window members obtained in Examples 1, 7, and 8, the conditions of the thermo-hygrostat were set to 50°C x 90% RH with reference to the conditions in <Dimensional change after high temperature and high humidity test>, and the resin window members were removed 240 hours after the set conditions were reached. Air bubbles were confirmed between the resin window member and the WGF only in the covers of Examples 7 and 8, and partial peeling of the WGF was observed. It is presumed that the large amount of acid components contained affected the interface between the resin window member and the adhesive surface of the WGF, causing the peeling.

[0320] As shown in Table 1, in the case of the working examples, good images were captured in the evaluation using a near-infrared camera, but in the resin window member shown in the comparative example, birefringence was large, and the reflected light rotated the polarized light to become elliptically polarized just before entering the near-infrared compatible polarizing element, so the...

Claims

1. The glass transition temperature is in the range of 115 to 150° C., and the absolute value of the photoelastic coefficient is 10×10 －１２ P －１ The average transmittance of the region having a wavelength of 380 nm or more and 660 nm or less is 15% or more, and the absolute value of the in-plane retardation at a wavelength of 850 nm is less than 20 nm on average. The continuous projected area is 5 cm ２ The above includes a molded article made of a resin composition containing a thermoplastic resin formed by injection molding, A resin window member for a near-infrared sensor.

2. 2. The resin window member for a near-infrared sensor according to claim 1, wherein a haze at a wavelength of 800 nm to 1000 nm after a reliability test at 110° C. for 2000 hours is 1.5% or less.

3. 3. The resin window member for a near-infrared sensor according to claim 1, having an M-scale Rockwell hardness of 90 or more.

4. 2. The resin window member for a near-infrared sensor according to claim 1, wherein in the region where the absolute value of the in-plane retardation at a wavelength of 850 nm is less than 20 nm on average, a difference between the average absolute value of the in-plane retardation at a wavelength of 810 nm and the average absolute value of the in-plane retardation at a wavelength of 850 nm is less than 5 nm.

5. 2. The resin window member for a near-infrared sensor according to claim 1, which is used in combination with a polarizing element having polarization separation ability in the near-infrared region and a near-infrared sensor, and is disposed between a subject and the near-infrared sensor.

6. 2. The resin window member for a near-infrared sensor according to claim 1, wherein the average transmittance at a wavelength of 800 nm or more and 1000 nm or less is 50% or more, and the average transmittance at a wavelength of 380 nm or more and 660 nm or less is 5% or less.

7. 2. The resin window member for a near-infrared sensor according to claim 1, having a convex or concave surface and a curved surface with a radius of curvature of 5000 mm or less.

8. The glass transition temperature is in the range of 115 to 150° C., and the absolute value of the photoelastic coefficient is 10×10 －１２ P －１ The molded article is made of a thermoplastic resin formed by injection molding, and has an average transmittance of 15% or more at a wavelength of 380 nm or more and 660 nm or less, and includes a region in which the absolute value of the in-plane retardation at a wavelength of 850 nm is less than 20 nm on average, the region being 50% or more of the continuous projected area relative to 100% of the entire projected area of ​​the molded article. A resin window member for a near-infrared sensor.

9. 2. The resin window member for a near-infrared sensor according to claim 1, wherein a polarizing element having a polarizing separation function in the near-infrared region is attached to the molded body.

10. 2. The resin window member for a near-infrared sensor according to claim 1, wherein the molded article has an acid component content of 100 ppm or less.

11. The resin window member for a near-infrared sensor according to claim 1 , wherein the molded body has a bending strength of 65 MPa or more.

12. A protective cover for a headset housing, comprising the resin window member for a near-infrared sensor according to claim 1.

13. A protective cover for a LiDAR for ranging, comprising the resin window member for a near-infrared sensor according to claim 1.

14. A protective cover for a LiDAR for facial authentication, comprising the resin window member for a near-infrared sensor according to claim 1.

15. A near-infrared sensor comprising the resin window member for a near-infrared sensor according to claim 1.

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