Film, optical module, and method for manufacturing molded article

Abstract

To provide a film with which warping is suppressed.SOLUTION: A film has an elastomer layer on a substrate, and a stress relaxation rate of the elastomer layer in at least one direction, which is calculated by the following formula 1, is 70% or more: [Formula 1] stress relaxation rate(%)=(A-B) / A×100. A stripe-shaped test piece is obtained by cutting out the elastomer layer to length 10 mm×width 30 mm taking at least one direction of the elastomer layer as a length direction. This stripe-shaped test piece is stretched in the length direction at a tensile speed of 200 mm / minute under an environment of temperature 25°C and relative humidity 45% by using a tensile test machine and stopped after being drawn to 50% of elongation. The stress value of the elastomer layer is continuously measured until 30 seconds after stoppage of elongation from the start of stretching. The stress relaxation rate (%) of the elastomer layer is calculated on the basis of formula 1 where A (N) represents the stress value that exhibited the highest stress within the measurement time and B (N) represents the stress value 30 seconds after stoppage of elongation.SELECTED DRAWING: Figure 5A

Description

[Technical Field]

[0001] The present invention relates to a film, an optical module, and a method for producing a molded article. [Background technology]

[0002] Sensor technology and communication technology using near-infrared rays have been developed or put into practical use. Because elements that receive near-infrared rays are also sensitive to visible light, near-infrared transmission filters that selectively transmit only near-infrared rays are used.

[0003] Conventional near-infrared transmission filters have mainly been black in color because they absorb visible light. Therefore, conventional near-infrared transmission filters have a problem of poor designability. Therefore, for example, Patent Document 1 discloses an optical filter that can realize an infrared transmission filter with high linear transmittance of infrared light and that is generally white in color.

[0004] On the other hand, near-infrared transmission filters are desired to be uniform films with little warpage. For example, a surface protection sheet for suppressing warpage of semiconductor wafers has been proposed, which has a substrate made of an antistatic coating layer containing an inorganic conductive filler and a cured product of a curable resin and a support film containing a cured product of the curable resin, and an adhesive layer, and the stress relaxation rate of the substrate after 1 minute at 10% elongation is 60% or more, and the Young's modulus of the substrate is 100 to 2000 MPa (see Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2022-69678 [Patent Document 2] Patent No. 6559150 Summary of the Invention [Problem to be solved by the invention]

[0006] When a film is made into a laminated structure, warping occurs as a problem, and there is a demand for reducing warping in film applications, particularly in applications where the film is used after molding.

[0007] The optical filter described in Patent Document 1 has a problem in that it breaks when bent and cannot be molded.

[0008] The surface protection sheet described in Patent Document 2 prevents static electricity caused by peeling electrification of semiconductor wafers and suppresses warping of the wafer after the surface protection sheet is peeled off, but does not suppress warping of the surface protection sheet itself, and no use in molding processing is disclosed.

[0009] An object of the embodiments of the present invention is to solve the above-mentioned problems in the prior art and to provide a film that is suppressed from warping. [Means for solving the problem]

[0010] A film according to an embodiment of the present invention has an elastomer layer on a substrate, and the elastomer layer has a stress relaxation rate of 70% or more in at least one direction, as calculated by the following formula 1: [Method for measuring stress relaxation rate] The elastomer layer is cut into a strip of 10 mm long x 30 mm wide, with at least one direction being the length direction. This strip of test piece is stretched in the length direction using a tensile tester at a tension speed of 200 mm / min in an environment of 25°C and 45% relative humidity, and is stretched to an elongation of 50% and then stopped. The stress value of the elastomer layer is continuously measured from the start of tension until 30 seconds after the stretching is stopped. The stress value that shows the highest stress within the measurement time is defined as "A" (N), and the stress value 30 seconds after the stretching is stopped is defined as "B" (N), and the stress relaxation rate (%) of the elastomer layer is calculated according to the following formula 1. [Formula 1] Stress relaxation rate (%) = (AB) / A × 100 [Effects of the Invention]

[0011] Embodiments of the present invention can provide a film with reduced warpage. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic explanatory diagram showing a method for measuring the curl value of a film according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram illustrating the optical properties of the film according to the embodiment of the present invention. [Figure 3] FIG. 3 is a schematic diagram showing a method for measuring the in-line transmittance of a film according to an embodiment of the present invention. [Figure 4] FIG. 4 is a schematic cross-sectional view showing an example of an elastomer layer in a film according to an embodiment of the present invention. [Figure 5A] FIG. 5A is a cross-sectional view showing an example of a film according to an embodiment of the present invention. [Figure 5B] FIG. 5B is a cross-sectional view showing another example of a film according to an embodiment of the present invention. [Figure 5C] FIG. 5C is a cross-sectional view showing another example of a film according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described in detail. Note that the embodiments are not limited by the following description and can be modified as appropriate within the scope of the present invention. Furthermore, in this specification, unless otherwise specified, the symbol "to" indicating a range of numerical values ​​means that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0014] Furthermore, when describing embodiments of the present invention with reference to the drawings, the same components in each drawing may be designated by the same reference numerals, and duplicated explanations may be omitted. Furthermore, the number, position, size, shape, etc. of components are not limited to the embodiments of the present invention, and may be any number, position, size, shape, etc. that is preferable for implementing the present invention.

[0015] (film) A film according to an embodiment of the present invention has an elastomer layer on a substrate, and the elastomer layer has a stress relaxation rate of 70% or more in at least one direction, as calculated by the following formula 1: -Method for measuring stress relaxation rate- The elastomer layer was cut into a strip of 10 mm long x 30 mm wide, with at least one direction being the length direction. This strip-shaped test piece was stretched in the length direction at a tension speed of 200 mm / min using a tensile tester at a temperature of 25°C and a relative humidity of 45%, and stretched to an elongation of 50% and then stopped. The stress value of the elastomer layer was continuously measured from the start of stretching until 30 seconds after stretching stopped. The stress value that showed the highest stress within that measurement time (peak top stress value) was designated "A" (N), and the stress value 30 seconds after stretching stopped was designated "B" (N), and the stress relaxation rate (%) of the elastomer layer was calculated according to the following formula 1: [Formula 1] Stress relaxation rate (%) = (AB) / A × 100

[0016] [Curl Value] The film according to the embodiment of the present invention is one that is suppressed from warping. The curl value of the film is preferably 2.0 mm or less, more preferably 1.5 mm or less, even more preferably 1.1 mm or less, and particularly preferably 0.0 mm.

[0017] -Method for measuring curl value- The curl value of a film is measured using a molded product molded at 150°C. FIG. 1 is a schematic diagram illustrating a method for measuring the curl value of a film. Specifically, a strip-shaped test piece having a length of 10 mm and a width of 30 mm is cut from the film, with at least one direction being the length direction. This strip-shaped test piece is heated to 150°C using a tensile tester. After reaching 150°C, it is left to stand for 10 seconds. Next, it is pulled in the length direction at a tensile speed of 200 mm / min in an environment of 150°C and 45% relative humidity, and stretched (elongated) to an elongation of 20% and then stopped. The temperature is then lowered to 40°C to obtain a molded product 10a. The film molded product 10a is placed on a horizontal table 20, and a ruler is placed vertically from the horizontal table 20. The lengths from the horizontal table to four points A, B, C, and D, which are the ends of the molded product 10a when viewed from the side (thickness direction) are measured. The average value of the lengths at these four points is taken as the "curl value" of the film according to the embodiment of the present invention.

[0018] [Whiteness] The film according to the embodiment of the present invention may exhibit a white color. In the embodiment of the present invention, the term "whiteness" refers to the degree of whiteness. In the embodiment of the present invention, the whiteness is measured by a spectrophotometer using the SCE method in the CIE 1976 color space with the D65 light source as the standard light source, and is expressed as the L of the backscattered light of the film. * It can be evaluated by the value of

[0019] L of the film according to an embodiment of the present invention * The value of L is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 60 or more, more preferably 70 or more, and even more preferably 75 or more. * The larger the value of L, the higher the whiteness. * If the value of L is 60 or more, it can be said that the film is generally white. * The upper limit of the value is 100.

[0020] In addition, when the film according to the embodiment of the present invention has layers other than the substrate and the elastomer layer, the layers can be selected so as not to affect the whiteness of the elastomer layer. Therefore, the whiteness of the film according to the embodiment of the present invention is synonymous with the whiteness of the elastomer layer in the film.

[0021] [Linear transmittance] The linear transmittance of the film according to the embodiment of the present invention to near-infrared light is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 40% or more, more preferably 50% or more, even more preferably 65% ​​or more, and particularly preferably 70% or more. When the linear transmittance of the film to near-infrared light is 40% or more, the elastomer layer of the film according to the embodiment of the present invention can also function as a near-infrared transmitting layer. The near-infrared transmitting layer refers to a filter layer having spectral properties that block at least a portion of visible light and transmit at least a portion of near-infrared light.

[0022] The definition of near-infrared light varies depending on the technical field, but in an embodiment of the present invention, "near-infrared light" refers to light that includes at least light (electromagnetic waves) with a wavelength in the range of 760 nm to 2,000 nm. This wavelength range is suitable for use in sensing or communication. Furthermore, in an embodiment of the present invention, "visible light" refers to light with a wavelength in the range of 400 nm to less than 760 nm.

[0023] The wavelength range of light in which the film according to an embodiment of the present invention has a linear transmittance of 40% or more for near-infrared light is not particularly limited as long as it is near-infrared light, and can be appropriately selected depending on the purpose. However, the wavelength range is preferably 810 nm or more and 1,700 nm or less, more preferably 840 nm or more and 1,650 nm or less, even more preferably 840 nm or more and 1,000 nm or less, and particularly preferably 840 nm or more and 950 nm or less.

[0024] If the film according to the embodiment of the present invention has an in-line transmittance of 40% or more for light with a wavelength of 810 nm or more and 1,700 nm or less, it can be suitably used in, for example, InGaAs sensors, InGaAs / GaAsSb sensors, CMOS sensors, NMOS sensors, CCD sensors, etc.

[0025] In addition, when the film according to the embodiment of the present invention has a layer other than the substrate and the elastomer layer, the layer may be selected so as not to affect the linear transmittance of the elastomer layer to near-infrared rays. Therefore, the linear transmittance of the film according to the embodiment of the present invention to near-infrared rays is synonymous with the linear transmittance of the elastomer layer in the film to near-infrared rays.

[0026] Next, the optical characteristics of the film according to the embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a schematic diagram for explaining an example of the optical characteristics of the film according to the embodiment of the present invention. When incident light I0 is incident on the film 10, a part of the incident light I0 is transmitted through the film 10 (transmitted light I i ), and part of it is reflected at the interface (interface reflected light R i ), and the other part is preferably scattered. The scattered light includes forward scattered light S emitted in front of the film 10. f and the backscattered light S emitted backward. b There is a saying.

[0027] The film 10 scatters visible light into backscattered light S b Since the backscattered light S b As a result, the film 10 exhibits a white color. Although a portion of the incident light I0 is absorbed by the film 10, the film 10 has a low absorptivity for light with wavelengths of 400 nm to 2,000 nm. The film 10 also has an excellent linear transmittance for near-infrared light. That is, most of the incident light I0 incident on the film 10 is transmitted as transmitted light I i and the forward scattered light S fBecause of its low density, when used in image sensors such as InGaAs sensors, InGaAs / GaAsSb sensors, CMOS sensors, NMOS sensors, and CCD sensors, it produces sharp images with strong contrast (brightness and darkness).

[0028] The linear transmittance of the film according to the embodiment of the present invention to near-infrared rays is measured using a spectrometer such as an ultraviolet-visible-near-infrared spectrophotometer, using the measurement method shown in Fig. 3. A specific method for measuring the linear transmittance of the film to near-infrared rays is as described in the examples below.

[0029] The film according to the embodiment of the present invention preferably has a linear transmittance spectrum with small dependency on the angle of incidence, and the linear transmittance when the angle of incidence of 940 nm near-infrared light is 60° is more preferably 80% or more, even more preferably 85% or more, and particularly preferably 90% or more, compared to the linear transmittance when the angle of incidence of 940 nm near-infrared light is 0°.

[0030] In the film according to an embodiment of the present invention, it is preferable that the portion of the curve where the linear transmittance increases monotonically from visible light to near-infrared light shifts to the longer wavelength side as the angle of incidence increases. If the portion of the curve where the linear transmittance increases monotonically from visible light to near-infrared light shifts to the shorter wavelength side as the angle of incidence increases, the shorter wavelength light that is intended to be blocked may be transmitted (light leakage) for obliquely incident light. In contrast, if the film according to an embodiment of the present invention shifts to the longer wavelength side as the angle of incidence increases, this reduces the linear transmittance for light on the shorter wavelength side, which is preferable in that light leakage is less likely to occur.

[0031] Such incidence angle dependency of the film according to the embodiment of the present invention is believed to be due to the fact that the fine particles in the elastomer layer contained in the film, which will be described later, form colloidal amorphous aggregates. In the film according to the embodiment of the present invention, the fine particles forming the colloidal amorphous aggregates decrease in linear transmittance for light on the shorter wavelength side as the incidence angle increases because the intensity of scattered light of visible light, particularly visible light on the longer wavelength side, increases. Therefore, when the film according to the embodiment of the present invention is viewed obliquely, the intensity of diffusely reflected light (backscattered light) increases, and the white luminance (L * ) can rise.

[0032] <Elastomer layer> [Stress relaxation rate] The stress relaxation rate of the elastomer layer of the film according to an embodiment of the present invention is 70% or more, preferably 75% or more, more preferably 80% or more, and even more preferably 85% or more. A stress relaxation rate of the elastomer layer of 70% or more can suppress warpage. The upper limit of the stress relaxation rate of the elastomer layer is not particularly limited, and a higher value is preferable because it can suppress warpage more effectively. In an embodiment of the present invention, the stress relaxation rate of the elastomer layer is determined by the above-described method for calculating a stress relaxation rate.

[0033] The peak top value A of the stress of the elastomer layer of the film is not particularly limited as long as the stress relaxation rate of the elastomer layer is 70% or more, but is preferably 5 MPa or less, more preferably 4 MPa or less, and even more preferably 3 MPa or less. The lower limit of the stress value A is 0 MPa, and the lower the value, the smaller the residual stress, making it less likely that the film will warp, which is preferable.

[0034] The stress value B of the elastomer layer of the film is not particularly limited as long as the stress relaxation rate of the elastomer layer is 70% or more. However, the upper limit of the stress value B is preferably 3 MPa or less, more preferably 2 MPa or less, and even more preferably 1 MPa or less.

[0035] The one direction in which the stress relaxation rate of the elastomer layer is 70% or more is the same as the one direction in which the stress value B is in the preferred range. Although this depends on the method for forming the elastomer layer in the production of the film, when the elastomer layer is formed by a coating method, a printing method or the like, a uniform elastomer layer can be formed, and therefore the "at least one direction" is not particularly limited.

[0036] The difference (AB) between the stress value A and the stress value B is not particularly limited, but is preferably 3 MPa or less, more preferably 2 MPa or less, and even more preferably 1 MPa or less.

[0037] Average Thickness The average thickness of the elastomer layer is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 1,000 μm or less, more preferably 500 μm or less, and even more preferably 350 μm or less. When the average thickness of the elastomer layer is 1,000 μm or less, sufficient photocurability can be obtained. The lower limit of the average thickness of the elastomer layer is also not particularly limited and can be selected appropriately depending on the purpose, but is preferably 50 μm or more, more preferably 100 μm or more. The upper and lower limits of the average thickness of the elastomer layer can be appropriately combined, and can be, for example, 50 μm to 1,000 μm, 50 μm to 500 μm, 50 μm to 350 μm, 100 μm to 1,000 μm, 100 μm to 500 μm, or 100 μm to 350 μm.

[0038] In the embodiments of the present invention, the "average thickness" of the elastomer layer refers to the average value of thicknesses at five points arbitrarily selected from the elastomer layer. The thickness of the elastomer layer can be measured by observing a cross section of the elastomer layer in the thickness direction using a transmission electron microscope (TEM) (e.g., HT7820, manufactured by Hitachi High-Technologies Corporation).

[0039] [material] The elastomer layer contains a matrix, fine particles dispersed in the matrix, and, if necessary, other components. Preferably, both the matrix and the fine particles are transparent to visible light.

[0040] -Matrix- The material constituting the matrix is ​​not particularly limited as long as it can make the stress relaxation rate of the elastomer layer 70% or more, and can be appropriately selected depending on the purpose. Examples include (meth)acrylic resin, urethane resin, and epoxy resin. These may be used alone or in combination of two or more. In the embodiment of the present invention, "(meth)acrylic" means at least one of "acrylic" and "methacrylic".

[0041] The matrix is ​​preferably formed using a curable resin. The curable resin may be a thermosetting resin or a photocurable resin, but from the viewpoint of mass productivity, it is preferable to use a photocurable resin.

[0042] The matrix is ​​preferably obtained by curing a monomer. The monomer that is the material of the matrix is ​​not particularly limited and can be appropriately selected depending on the purpose. It may be a monofunctional compound or a polyfunctional compound, but a monofunctional compound is preferred.

[0043] Examples of monofunctional compounds used as matrix materials include benzyl (meth)acrylates. Although there are no particular limitations on the benzyl (meth)acrylates, compounds represented by the following general formula (1) are preferred. In the embodiments of the present invention, "(meth)acrylate" refers to at least one of "acrylate" and "methacrylate."

[0044] [ka] (In general formula (1), R represents hydrogen or a phenoxy group.)

[0045] Among the compounds represented by general formula (1), o-substituted or m-substituted phenoxybenzyl (meth)acrylate compounds are preferred, and m-substituted phenoxybenzyl (meth)acrylate compounds are more preferred.

[0046] The content of the matrix in the elastomer layer is not particularly limited and can be selected appropriately depending on the purpose. When the entire elastomer layer is taken as 100 parts by mass, the content is preferably 30 parts by mass or more and 96 parts by mass or less, more preferably 35 parts by mass or more and 80 parts by mass or less, and even more preferably 40 parts by mass or more and 70 parts by mass or less.

[0047] The matrix content in the elastomer layer can be measured by 3D structural analysis using a real-time 3D analytical FIB-SEM combined instrument (NX9000, manufactured by Hitachi High-Tech Corporation).

[0048] -Fine particles- The fine particles are not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include inorganic fine particles, resin fine particles, etc. These may be used alone or in combination of two or more types.

[0049] The inorganic fine particles are not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include silica fine particles, titanium oxide fine particles, and zirconia fine particles. Among these, silica fine particles are preferred as the fine particles. The silica fine particles are not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include silica fine particles synthesized by the Stöber method and hollow silica fine particles containing air.

[0050] The resin microparticles are not particularly limited and can be appropriately selected depending on the purpose, but microparticles made of at least one selected from the group consisting of polystyrene and polymethyl methacrylate are preferred, and microparticles made of at least one selected from the group consisting of crosslinked polystyrene, crosslinked polymethyl methacrylate, and crosslinked styrene-methyl methacrylate copolymer are more preferred. For example, polystyrene microparticles or polymethyl methacrylate microparticles synthesized by emulsion polymerization can be used as such microparticles. Hollow resin microparticles containing air can also be used.

[0051] Among these, inorganic fine particles are preferred as the fine particles because they are excellent in heat resistance and light resistance, and silica fine particles are more preferred because they can provide a sharp particle size distribution.

[0052] The fine particles preferably form a colloidal amorphous aggregate in the elastomer layer. In the embodiment of the present invention, the "colloidal amorphous aggregate" refers to an aggregate of colloidal particles with a particle size of 1 nm to 1 μm, which does not have long-range order and does not cause Bragg reflection. This is in contrast to the case where colloidal particles are distributed so as to have long-range order, which results in a so-called colloidal crystal (a type of photonic crystal), and Bragg reflection occurs. In other words, it is preferable that the fine particles (colloidal particles) in the elastomer layer do not form a diffraction grating.

[0053] Colloidal crystals, which have an orderly structure in which colloidal particles are regularly arranged, reflect light of a wavelength corresponding to their lattice constant due to Bragg diffraction. For example, colloidal crystals in which submicron-order colloidal particles are regularly arranged reflect light of wavelengths ranging from ultraviolet light or visible light to infrared light. When such colloidal crystals are used to reflect visible light, they can produce so-called structural colors such as iridescence. Therefore, the presence or absence of an iridescent color can be visually confirmed to determine whether or not the particles constitute a colloidal amorphous aggregate.

[0054] Furthermore, whether or not the microparticles form colloidal amorphous aggregates, and the distribution state of the microparticles in the colloidal amorphous aggregates, can also be confirmed using the average value (La) and standard deviation (Ld) of the distance between the centers of gravity of adjacent microparticles as indicators. The average value (La) of the distance between the centers of gravity of adjacent microparticles is not particularly limited, but is preferably 100 nm or more, more preferably 150 nm or more, even more preferably 175 nm or more, and particularly preferably 200 nm or more. The upper limit of the average value (La) of the distance between the centers of gravity of adjacent microparticles is also not particularly limited, but is preferably 600 nm or less, more preferably 500 nm or less.

[0055] The average (La) and standard deviation (Ld) of the distance between the centers of gravity of adjacent microparticles can be calculated from cross-sectional transmission electron microscope (TEM) images of the elastomer layer. Specifically, when the thickness of the elastomer layer is d, a test piece with a thickness equal to the average particle size of the microparticles is cut using a microtome in a direction perpendicular to the thickness direction of the elastomer layer at a position d / 2 relative to the cross-sectional direction (thickness direction). This provides a sample for TEM observation. Using a TEM (e.g., HT7820, manufactured by Hitachi High-Tech Corporation) to obtain cross-sectional TEM images containing images of 200 or more microparticles, image processing software (e.g., Image J, open source) can be used to perform automatic Delaunay diagram analysis of the microparticles to determine the average (La) and standard deviation (Ld) of the distance between the centers of gravity of adjacent microparticles. The coefficient of variation (CV value of the distance) can also be calculated from the average distance between the centers of gravity (hereinafter sometimes referred to as the "average distance between the centers of gravity") and standard deviation. In the embodiment of the present invention, when calculating the distance between the centers of gravity, only particles having a particle size of 150 nm or more are considered, and particles having a particle size of less than 150 nm are not considered.

[0056] The coefficient of variation of the average distance between the centers of gravity of fine particles is not particularly limited, but is preferably 10% or more, more preferably 15% or more, even more preferably 20% or more, and particularly preferably 25% or more. The upper limit of the coefficient of variation of the average distance between the centers of gravity of fine particles is also not particularly limited, but is preferably 45% or less, more preferably 40% or less, and even more preferably 35% or less. The lower and upper limits of the coefficient of variation of the average distance between the centers of gravity of fine particles can be appropriately combined, and are preferably 10% to 45% or less, more preferably 15% to 40% or less, even more preferably 20% to 40% or less, and particularly preferably 25% to 35% or less. When the coefficient of variation of the average distance between the centers of gravity of fine particles is 10% or more, the long-range order is weak, and angle-dependent reflection color due to Bragg reflection is unlikely to be exhibited. Furthermore, when the coefficient of variation of the average distance between the centers of gravity of fine particles is 45% or less, the effect of Mie scattering is small, and the wavelength dependence of light scattering tends to be strong.

[0057] The average particle size of the microparticles is not particularly limited and can be selected appropriately depending on the purpose. However, it is preferable to include monodisperse microparticles with an average particle size of at least one-tenth of the wavelength of near-infrared light. For near-infrared light with a wavelength of 760 nm to 2,000 nm, the average particle size of the microparticles is more preferably at least 80 nm, even more preferably 150 nm or more, and particularly preferably 200 nm or more. The upper limit of the average particle size of the microparticles is also not particularly limited, but is preferably 300 nm or less. The lower and upper limits of the average particle size of the microparticles can be appropriately combined. For near-infrared light with a wavelength of 760 nm to 2,000 nm, the average particle size of the microparticles is more preferably 80 nm to 300 nm, even more preferably 150 nm to 300 nm, and particularly preferably 200 nm to 300 nm. The microparticles may also include two or more monodisperse microparticles with different average particle sizes. Using monodisperse microparticles with an average particle size of at least one-tenth of the wavelength of near-infrared light can increase the linear transmittance of near-infrared light. This differs from Rayleigh scattering in principle.

[0058] The shape of the fine particles is not particularly limited, but is preferably approximately spherical.

[0059] In the embodiments of the present invention, the term "microparticles (plural microparticles)" is also used to mean an aggregate of microparticles. Furthermore, "monodisperse microparticles" preferably have a coefficient of variation (standard deviation / average particle diameter expressed as a percentage) of 20% or less, more preferably 10% or less, and even more preferably 1% to 5%.

[0060] In the embodiments of the present invention, the average particle size of the microparticles refers to the average particle size determined by a focused ion beam scanning electron microscope (hereinafter sometimes referred to as "FIB-SEM"). Specifically, the average particle size of the microparticles can be calculated by the method described in the examples.

[0061] The content of the fine particles in the elastomer layer is not particularly limited and can be selected appropriately depending on the purpose. When the entire elastomer layer is taken as 100 parts by mass, the content is preferably 6 parts by mass or more and 80 parts by mass or less, more preferably 20 parts by mass or more and 70 parts by mass or less, and even more preferably 20 parts by mass or more and 60 parts by mass or less.

[0062] The content of fine particles in the elastomer layer can be measured by 3D structural analysis using a real-time 3D analytical FIB-SEM combined instrument (NX9000, manufactured by Hitachi High-Tech Corporation).

[0063] --Refractive index-- The refractive index of the matrix for visible light is n M , the refractive index of the microparticles is n P Then, |n M -n PAlthough the refractive index difference (hereinafter sometimes abbreviated as "refractive index difference") is not particularly limited, it is preferably 0.01 or more and 0.6 or less, and more preferably 0.03 or more and 0.11 or less. If the refractive index difference is less than 0.01, the scattering intensity will be weak, making it difficult to obtain the desired optical properties. If the refractive index difference is more than 0.6, the linear transmittance for near-infrared rays may decrease. Furthermore, when the refractive index difference is set to 0.6 by using, for example, zirconia fine particles (refractive index 2.13) and an acrylic resin, the linear transmittance for near-infrared rays can be adjusted by reducing the thickness. In this way, the linear transmittance for near-infrared rays can also be adjusted, for example, by controlling the film thickness and the refractive index difference. Furthermore, depending on the application, it can also be used by overlapping with a filter that absorbs near-infrared rays. The refractive index for visible light can be represented, for example, by the refractive index for light of 546 nm. Herein, unless otherwise specified, the refractive index refers to the refractive index for light of 546 nm.

[0064] -Other ingredients- The other components in the elastomer layer are not particularly limited as long as they do not impair the effects of the present invention and can be appropriately selected depending on the purpose, and examples thereof include a polymerization initiator used when curing the matrix to form it. The polymerization initiator can be appropriately selected depending on the curing method, and may be a thermal polymerization initiator or a photopolymerization initiator.

[0065] Examples of photopolymerization initiators include carbonyl compounds (e.g., benzoin ether, benzophenone, anthraquinone, thioxane, ketal, acetophenone, 2-hydroxy-2-methylpropiophenone, etc.), sulfur compounds (e.g., disulfides, dithiocarbamates, etc.), organic peroxides (e.g., benzoyl peroxide, etc.), azo compounds, transition metal complexes, polysilane compounds, dye sensitizers, etc. These may be used alone or in combination of two or more.

[0066] The content of the photopolymerization initiator in the elastomer layer is not particularly limited and can be selected appropriately depending on the purpose, but it is preferably 0.05 parts by mass or more and 3 parts by mass or less, and more preferably 0.05 parts by mass or more and 2 parts by mass or less, relative to 100 parts by mass of the monomer that constitutes the matrix.

[0067] [[Example of Implementation]] An embodiment of the elastomer layer will be specifically described with reference to the drawings. FIG. 4 is a schematic cross-sectional view showing an example of an elastomer layer in a film according to an embodiment of the present invention. The elastomer layer 11 includes a matrix 12 that is transparent to visible light and transparent microparticles 14 dispersed in the transparent matrix 12. The microparticles 14 preferably form colloidal amorphous aggregates. The elastomer layer 11 may also include other microparticles that do not disrupt the colloidal amorphous aggregates formed by the microparticles 14.

[0068] The elastomer layer 11 has a substantially flat surface, as shown schematically in Fig. 4. Here, a substantially flat surface means a surface that does not have an uneven structure of a size that would scatter (diffract) or diffusely reflect visible light or near-infrared light. Furthermore, the elastomer layer 11 does not contain cholesteric liquid crystal. Cholesteric liquid crystal broadly includes high molecular weight liquid crystals, low molecular weight liquid crystals, liquid crystal mixtures thereof, and liquid crystal materials obtained by mixing these with a crosslinking agent and solidifying them by crosslinking, etc., and which exhibit a cholesteric phase.

[0069] <Base material> The material of the substrate is not particularly limited and can be appropriately selected depending on the purpose. Examples include resins such as polyethylene (PE), polypropylene (PP) (including biaxially oriented polypropylene (OPP), uniaxially oriented polypropylene (CPP), etc.), polyethylene terephthalate (PET), polycarbonate (PC), triacetyl cellulose (TAC), polyimide (PI), methyl methacrylate (PMMA), and cycloolefin polymer (COP).

[0070] The substrate is preferably transparent to visible light. The linear transmittance of the substrate to near-infrared light is not particularly limited and can be appropriately selected depending on the purpose, but is preferably in the same range as the linear transmittance of the elastomer layer to near-infrared light.

[0071] The average refractive index of the substrate for visible light is not particularly limited and can be appropriately selected depending on the purpose, but a smaller difference in the average refractive index between the substrate and the elastomer layer is preferable because it reduces loss due to interfacial reflection, and is more preferably 0.08 or less, even more preferably 0.03 or less, and particularly preferably 0.01 or less. The average refractive index of the substrate for visible light can be measured using an Abbe refractometer (for example, Model DR-A1, manufactured by Atago Co., Ltd.).

[0072] The average thickness of the substrate is not particularly limited as long as it does not impair the effects of the present invention, and can be appropriately selected depending on the purpose.

[0073] <Other layers> The film according to the embodiment of the present invention may have layers other than the substrate and the elastomer layer, as long as the effects of the present invention are not impaired.

[0074] When the film according to the embodiment of the present invention has other layers, the other layers may include, for example, an adhesive layer, a filter layer having optical properties different from those of the substrate and the elastomer layer, a near-infrared absorbing layer, a color filter layer, a print layer, a protective layer, etc.

[0075] The shape, structure, and size of the other layers are not particularly limited and can be appropriately selected depending on the purpose. For example, the shape may be a film, a plate, or the like.

[0076] <<Adhesive layer>> The adhesive layer is a layer that bonds the substrate and the elastomer layer. Therefore, when the film includes an adhesive layer, the substrate, the adhesive layer, and the elastomer layer are laminated in this order. The adhesive layer may also be a layer that bonds the substrate or the elastomer layer to another layer.

[0077] The material for the adhesive layer is not particularly limited and can be appropriately selected from those used for optical components depending on the purpose, and examples include (meth)acrylic resins such as (meth)acrylic acid, (meth)acrylic acid esters, and (meth)acrylamide.

[0078] The adhesive layer is preferably transparent to visible light. The linear transmittance of the adhesive layer to near-infrared light is not particularly limited and can be appropriately selected depending on the purpose, but is preferably in the same range as the linear transmittance of the elastomer layer to near-infrared light.

[0079] The average refractive index of the adhesive layer for visible light is not particularly limited and can be appropriately selected depending on the purpose, but the smaller the difference in average refractive index between the adhesive layer and the substrate and elastomer layer, the less loss due to interfacial reflection, so it is preferable, and is more preferably 0.08 or less, even more preferably 0.03 or less, and particularly preferably 0.01 or less. The average refractive index of the adhesive layer for visible light can be measured using an Abbe refractometer (for example, Model: DR-A1, manufactured by Atago Co., Ltd.).

[0080] The average thickness of the adhesive layer is not particularly limited as long as it does not impair the effects of the present invention, and can be selected appropriately depending on the purpose, but is preferably 5 μm or more and 200 μm or less, more preferably 5 μm or more and 100 μm or less, even more preferably 10 μm or more and 75 μm or less, and particularly preferably 10 μm or more and 50 μm or less.

[0081] In the embodiments of the present invention, the "average thickness" of the adhesive layer refers to the average value of thicknesses at five points arbitrarily selected from the adhesive layer. The thickness of the adhesive layer can be measured by observing a cross section of the adhesive layer in the thickness direction using a transmission electron microscope (TEM) (e.g., HT7820, manufactured by Hitachi High-Technologies Corporation).

[0082] <<Near-infrared absorbing layer>> The near-infrared absorbing layer is a filter layer that absorbs near-infrared rays. The near-infrared absorbing layer is preferably disposed on the side where incident light that has entered the near-infrared absorbing layer is transmitted and transmitted light is emitted. By adopting such a configuration, for example, in an infrared sensor, the near-infrared absorbing layer can efficiently absorb near-infrared rays.

[0083] <<Color filter layer>> The color filter layer is a filter layer that exhibits black or other colors (e.g., yellow, red, blue, pink, brown, etc.). The film according to the embodiment of the present invention exhibits white color, so even when a color filter layer is used in combination with the film, the color does not interfere with the color, thereby enhancing the design.

[0084] <<Printed layer>> The print layer is a layer having a desired printed image such as a color or pattern (for example, letters, pictures, photographs, etc.). By printing the desired printed image using an infrared-transmitting ink, a film having rich colors and a rich design can be obtained without reducing the linear transmittance of the film of the embodiment of the present invention to near-infrared rays. Furthermore, since the film of the embodiment of the present invention exhibits a white color, the design can be enhanced by further including a print layer.

[0085] The print layer is preferably disposed on the surface of the elastomer layer. The print layer may be formed directly on the surface of the elastomer layer, or a transparent film on which the print layer is formed may be disposed on the elastomer layer.

[0086] As the infrared transmitting ink, a known infrared transmitting ink may be selected depending on the application or the wavelength of the near infrared light to be transmitted.

[0087] In the embodiments of the present invention, the terms "on," "disposed on the surface of," "disposed on the side where transmitted light is emitted," and the like of one layer mean that one layer can be connected or bonded to, directly above, or on top of, the other layer, i.e., that another layer may be interposed between one layer and the other layer.

[0088] <<Protective layer>> The protective layer is a layer that protects the film. The protective layer may be disposed on one side or both sides of the film. When the protective layer is disposed on one side, it is preferably disposed on the side opposite to the substrate.

[0089] The protective layer is peeled off when the film is used. When the film has a protective layer, the film is advantageous in that it is easy to store and transport, and has excellent handleability.

[0090] The protective layer is not particularly limited as long as it does not affect the film, and any known release sheet can be used.

[0091] The release sheet is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include paper such as kraft paper, glassine paper, and fine paper; resin films such as polyethylene, polypropylene (biaxially oriented polypropylene (OPP), uniaxially oriented polypropylene (CPP)), and polyethylene terephthalate (PET); laminated paper in which paper and a resin film are laminated together; and paper that has been sealed with clay, polyvinyl alcohol, or the like and then subjected to a release treatment with a silicone resin or the like on one or both sides. These may be used alone or in combination of two or more.

[0092] <Structure> The film according to the embodiment of the present invention may have a two-layer structure consisting of only a substrate and an elastomer layer, a laminate structure of a substrate and an elastomer layer and other layers, or a laminate structure having a plurality of substrate and elastomer layers and other layers. When the film according to the embodiment of the present invention has a laminate structure, the order of lamination is not particularly limited as long as it does not impair the effects of the present invention, and can be appropriately selected depending on the purpose.

[0093] 5A to 5C are cross-sectional views showing an example of a film according to an embodiment of the present invention. Film 10 in Fig. 5A has a two-layer structure consisting of only substrate 30 and elastomer layer 11. Film 10 in Fig. 5B has a three-layer structure consisting of substrate 30, adhesive layer 40, and elastomer layer 11. Film 10 in Fig. 5C has a five-layer structure consisting of substrate 30, adhesive layer 40a, elastomer layer 11, adhesive layer 40b, color filter layer 41, adhesive layer 40c, and print layer 42.

[0094] The structure, shape, and size of the film according to the embodiment of the present invention are not particularly limited and can be appropriately selected depending on the purpose. The structure of the film according to the embodiment of the present invention may be a two-dimensional structure (planar structure) or a three-dimensional structure (stereoscopic structure). Specific examples of the film shape include a three-dimensional film formed by forming a film-like film on the surface of an object having a three-dimensional structure using a known coating method. In such embodiments, the shape of the surface of the object having a three-dimensional structure is not particularly limited and can be any shape, such as a shape consisting of part or all of a sphere, a shape consisting of an arbitrarily shaped curved surface, or a shape consisting of part or all of a polyhedron surface. However, it is preferable that the surface of the object does not cause light scattering.

[0095] The thickness of the film according to the embodiment of the present invention is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 μm to 10 mm, more preferably 10 μm to 5 mm, and even more preferably 10 μm to 2 mm. When the thickness of the film according to the embodiment of the present invention is 10 μm to 10 mm, warping can be suppressed.

[0096] <Manufacturing method> The method for producing the film according to the embodiment of the present invention is not particularly limited, and any known method can be used, but the method for producing the film according to the embodiment of the present invention described below is preferably used.

[0097] <Application> As described above, the film according to the embodiment of the present invention can suppress warpage by setting the stress relaxation rate of the elastomer layer to 70% or more. Therefore, the film according to the embodiment of the present invention can be suitably used as an optical filter. For example, the film according to the embodiment of the present invention can be suitably used as an optical filter applied to image sensors such as InGaAs sensors, InGaAs / GaAsSb sensors, CMOS sensors, NMOS sensors, and CCD sensors, sensing devices using these image sensors (e.g., infrared cameras), communication devices, solar cells, heaters (e.g., heaters using infrared rays), and power supply devices (e.g., optically powered devices using infrared rays).

[0098] (Film manufacturing method) The film manufacturing method according to the embodiment of the present invention is carried out in the following two embodiments depending on the layer structure.

[0099] <Film Manufacturing Method Embodiment 1> The method for producing the film of embodiment 1 includes a step of dispersing fine particles in a curable resin to prepare a curable resin composition (hereinafter, this step may be referred to as a "curable resin composition preparation step"), a step of applying the curable resin composition to the surface of a substrate (hereinafter, this step may be referred to as an "application step"), and a step of curing the curable resin contained in the curable resin composition applied to the surface of the substrate to form an elastomer layer (hereinafter, this step may be referred to as an "elastomer layer formation step"), and may further include other steps as necessary.

[0100] <<Curable resin composition preparation process>> The curable resin composition preparation step is a step of dispersing fine particles in a curable resin to prepare a curable resin composition.

[0101] The curable resin in the curable resin composition preparation step contains at least a material that constitutes the matrix of the elastomer layer, and further contains other components of the elastomer layer as necessary.

[0102] The fine particles in the curable resin composition preparation step can be appropriately selected from the fine particles in the elastomer layer.

[0103] The method for preparing the curable resin composition is not particularly limited as long as it is a method that can mix the material constituting the matrix, the fine particles, and, if necessary, other components, and can disperse the fine particles in the material constituting the matrix. Examples of the method include a preparation method using a known device, such as a mixing device or a dispersing device, such as a homomixer or a homogenizer (e.g., an ultrasonic homogenizer, a high-pressure homogenizer, etc.).

[0104] The temperature and time for preparing the curable resin composition are not particularly limited and can be appropriately selected depending on the purpose, provided that the temperature for preparation is below the curing temperature of the curable resin composition.

[0105] <<Application process>> The application step is a step of applying the curable resin composition to the surface of a substrate.

[0106] In the application step, in order to impart sufficient photocurability to the film, the curable resin composition is preferably applied to the surface of the substrate so that the average thickness after curing is 1,000 μm or less, more preferably 500 μm or less, and even more preferably 350 μm or less. The thickness of the elastomer layer can be adjusted by the amount of curable resin composition applied in the application step.

[0107] The substrate in the application step can be appropriately selected from the substrates of the film according to the embodiments of the present invention.

[0108] The method for applying the curable resin composition to the surface of the substrate is not particularly limited and can be appropriately selected from known methods. Examples include coating methods such as dip coating, spray coating, die coating, roll coating, and blade coating, and printing methods.

[0109] <<Elastomer layer formation process>> The elastomer layer forming step is a step of forming an elastomer layer by curing the curable resin contained in the curable resin composition applied to the surface of the substrate.

[0110] The method for curing the curable resin is not particularly limited and can be appropriately selected depending on the properties of the curable resin, the type of polymerization initiator in the curable resin composition, and the like. The method may be heat curing or photocuring, but photocuring is preferred from the viewpoint of mass productivity.

[0111] The temperature and time for thermal curing, and the wavelength, illuminance, and time for photocuring are not particularly limited, and can be appropriately selected depending on the properties of the curable resin, the type of polymerization initiator in the curable resin composition, etc.

[0112] <<Other processes>> The other steps in the method for producing the film of embodiment 1 are not particularly limited, and examples include steps for forming other layers described in the <Other Layers> section of (Film). The method for forming the other layers is not particularly limited, and can be appropriately selected from known methods.

[0113] <Film manufacturing method embodiment 2> The method for producing a film of embodiment 2 includes a step of dispersing fine particles in a curable resin to prepare a curable resin composition (hereinafter, sometimes referred to as a "curable resin composition preparation step"), a step of applying the curable resin composition to the surface of a temporary support (hereinafter, sometimes referred to as an "application step"), a step of curing the curable resin contained in the curable resin composition applied to the surface of the temporary support to form an elastomer layer (hereinafter, sometimes referred to as an "elastomer layer formation step"), a step of bonding an adhesive layer to the surface of the elastomer layer opposite to the surface on which the temporary support is arranged (hereinafter, sometimes referred to as an "adhesive layer bonding step"), and a step of bonding a substrate onto the adhesive layer (hereinafter, sometimes referred to as a "substrate bonding step"), and may further include other steps as necessary.

[0114] <<Curable resin composition preparation process>> The curable resin composition preparation step in the film production method of embodiment 2 is the same as the curable resin composition preparation step in the film production method of embodiment 1, and therefore a description thereof will be omitted.

[0115] <<Application step and elastomer layer forming step>> The application step and the elastomer layer forming step are performed in the same manner as in the film manufacturing method of embodiment 1, except that in the application step and the elastomer layer forming step in the film manufacturing method of embodiment 1, the substrate is changed to a temporary support.

[0116] The temporary support is not particularly limited as long as it allows a film to be produced on its surface and does not affect the film, particularly the near-infrared transmitting layer in the film. For example, a material similar to the protective layer in the film according to an embodiment of the present invention can be used.

[0117] <<Adhesive layer bonding process>> The adhesive layer bonding step is a step of bonding an adhesive layer to the surface of the elastomer layer opposite to the surface on which the temporary support is disposed.

[0118] The method for joining the adhesive layer to the surface opposite to the surface on which the temporary support of the elastomer layer is arranged is not particularly limited, and examples include a method of attaching an adhesive layer such as a known adhesive sheet to the surface on which the temporary support of the elastomer layer is arranged, and a method of applying an adhesive composition that will serve as the material for the adhesive layer to the surface on which the temporary support of the elastomer layer is arranged and curing it.

[0119] When applying a pressure-sensitive adhesive composition, the curable resin composition forming the elastomer layer and the pressure-sensitive adhesive composition may be cured simultaneously or separately, i.e., the elastomer layer forming step and the pressure-sensitive adhesive layer bonding step may be performed simultaneously or separately.

[0120] -Adhesive composition- The pressure-sensitive adhesive composition contains, for example, a monomer, a solvent, a polymerization initiator, and the like.

[0121] --monomer-- The monomer is not particularly limited as long as it can form an adhesive layer, and may be a monofunctional compound or a polyfunctional compound, but it is preferable that the monomer is capable of forming an adhesive layer containing a (meth)acrylic resin.

[0122] Examples of monomers capable of forming an adhesive layer containing a (meth)acrylic resin include linear or branched alkyl esters of (meth)acrylic acid. In the linear or branched alkyl esters of (meth)acrylic acid, the number of carbon atoms in the alkyl group is not particularly limited and may be, for example, 1 or more, 2 or more, 3 or more, or 4 or more, or may be, for example, 18 or less, 16 or less, 14 or less, 12 or less, 10 or less, or 8 or less. The upper and lower limits of the number of carbon atoms in the alkyl group can be appropriately combined.

[0123] The alkyl group may be substituted with, for example, one or more substituents, or may be unsubstituted. Examples of the substituents include a hydroxyl group. When the alkyl group has a plurality of substituents, the substituents may be the same or different.

[0124] Specific examples of linear or branched alkyl esters of (meth)acrylic acid include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, etc. These may be used alone or in combination of two or more.

[0125] The content of the monomer in the pressure-sensitive adhesive composition is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 10% by mass or more and 60% by mass or less, more preferably 10% by mass or more and 50% by mass or less, even more preferably 15% by mass or more and 40% by mass or less, and particularly preferably 15% by mass or more and 25% by mass or less.

[0126] --solvent-- The solvent is not particularly limited, and examples thereof include ethyl acetate.

[0127] --Polymerization initiator-- The polymerization initiator is not particularly limited and can be appropriately selected from known polymerization initiators.

[0128] <<Base material bonding process>> The substrate bonding step is a step of bonding a substrate onto the adhesive layer. The method for bonding the substrate onto the adhesive layer is not particularly limited, and examples thereof include a method of attaching the substrate to the surface of the adhesive layer opposite to the surface on which the elastomer layer is disposed.

[0129] The substrate in the substrate bonding step can be appropriately selected from the substrates of the film according to the embodiments of the present invention.

[0130] (Optical module) The optical module of an embodiment of the present invention includes a device having a near-infrared receiving unit, a film of an embodiment of the present invention arranged in front of the near-infrared receiving unit of the device, and may further include other components as necessary.

[0131] <Device equipped with a near-infrared receiver> The device having a near-infrared receiving unit is not particularly limited, and examples thereof include a sensing device, a communication device, a solar cell, a heater, and a power supply device. The optical module according to the embodiment of the present invention may include one or more of these devices having a near-infrared receiving unit.

[0132] <Film> The film is a film according to an embodiment of the present invention, and is as described in the (Film) section, so a description thereof will be omitted.

[0133] <Other materials> Other components in the optical module of the embodiment of the present invention are not particularly limited as long as they do not impair the effects of the present invention, and include well-known components that are commonly used in sensing devices, communication devices, solar cells, heaters, and power supply devices.

[0134] (Method of manufacturing a molded body) The method for producing a molded article according to an embodiment of the present invention includes a step of processing a film according to an embodiment of the present invention into a predetermined shape (hereinafter, sometimes referred to as a "processing step"), and may further include other steps as necessary.

[0135] <Processing process> The processing step is a step of processing the film according to the embodiment of the present invention into a predetermined shape.

[0136] The processing method in the processing step is not particularly limited, and an appropriate processing method can be selected according to the desired shape. When a three-dimensional (3D) shape is desired, methods such as heat pressing, insert molding, and extrusion molding can be used. When a two-dimensional (2D) shape is desired, methods such as stretching can be used.

[0137] The heating temperature in the processing step is not particularly limited, but is preferably 80°C to 200°C, and more preferably 100°C to 180°C.

[0138] In the processing step, the stretching speed in the case of stretching is not particularly limited, but is preferably 50 mm / min to 5,000 mm / min, and more preferably 100 mm / min to 1,000 mm / min.

[0139] (Molded body) The molded article according to the embodiment of the present invention is obtained by thermoforming the film according to the embodiment of the present invention. The molded article according to the embodiment of the present invention has at least the film, and may further have other layers as necessary. The molded article according to the embodiment of the present invention is suitably produced by the method for producing a molded article according to the embodiment of the present invention.

[0140] <Application> The molded article according to the embodiment of the present invention has a film according to the embodiment of the present invention in which warping is suppressed, and therefore is suitable for use in image sensors such as InGaAs sensors, InGaAs / GaAsSb sensors, CMOS sensors, NMOS sensors, and CCD sensors, sensing devices using these image sensors (e.g., infrared cameras), communication devices, solar cells, heaters (e.g., heaters using infrared rays), and power supply devices (e.g., optically powered devices using infrared rays). [Example]

[0141] The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these examples in any way.

[0142] Example 1 <Preparation of elastomer layer> 50 parts by mass of an acrylic monomer (light acrylate POB-A, 3-phenoxybenzyl acrylate represented by the following structural formula (1), average refractive index for light with a wavelength of 546 nm at 25°C: 1.566, manufactured by Kyoeisha Chemical Co., Ltd.) (hereinafter sometimes abbreviated as "POB-A") and 50 parts by mass (solid content) of silica microparticles dispersed in methyl ethyl ketone (MEK) (MEK-ST-2040, solid content 40% by mass, manufactured by Nissan Chemical Co., Ltd.) were weighed into a recovery flask. The mixture was then heated in an evaporator (EYEL4, manufactured by Tokyo Rikakikai Co., Ltd.) at 200 hPa and 60°C for 30 minutes to distill off the MEK, preparing curable resin composition A. To 100 parts by mass of the resulting curable resin composition A, 2 parts by mass of a photopolymerization initiator (2-hydroxy-2-methylpropiophenone, manufactured by Tokyo Chemical Industry Co., Ltd.) were added and stirred. Next, the composition was applied to the surface of a PET film (MRE75T302, manufactured by Mitsubishi Chemical Corporation) using an applicator, and the resulting film was sandwiched between the PET films (MRE75T302). Next, ultraviolet light was applied using a UV irradiation device (manufactured by Quark Technology Corporation) to photopolymerize and harden the curable resin composition A, producing an elastomer layer with a thickness of 200 μm.

[0143] [ka]

[0144] <Lamination of adhesive layer> One of the two PET films was peeled off from the elastomer layer, and an adhesive sheet (LUCIACS TM CS9861UAS, manufactured by Nitto Denko Corporation) was attached to the film to form an adhesive layer.

[0145] <Lamination of substrates> A substrate (PET film, Lumirror (registered trademark), #75-QV22, thickness 75 μm, Toray Industries, Inc.) was attached to the adhesive layer laminated on the elastomer layer.

[0146] The other PET film was peeled off from the elastomer layer to produce film 10 of Example 1, which is composed of substrate 30, adhesive layer 40, and elastomer layer 11, as shown in FIG. 5B.

[0147] Example 2 A film 10 of Example 2, consisting of a substrate 30, an adhesive layer 40, and an elastomer layer 11, was produced in the same manner as in Example 1, except that the preparation of the elastomer layer in Example 1 was changed as follows.

[0148] <Preparation of elastomer layer> Silica microparticles (MEK-ST-2040, solids content 40% by mass, manufactured by Nissan Chemical Industries, Ltd.) dispersed in methyl ethyl ketone (MEK) were placed in a recovery flask and heated in an evaporator (EYEL4, manufactured by Tokyo Rikakikai Co., Ltd.) at 100 hPa and 60°C for 30 minutes to remove the MEK. Next, 50 parts by mass of an acrylic monomer (Viscoat #160, benzyl acrylate represented by the following structural formula (2), average refractive index for light with a wavelength of 546 nm at 25°C: 1.519, manufactured by Osaka Organic Chemical Industry Co., Ltd.) (hereinafter sometimes abbreviated as "BZA") and 50 parts by mass (solids content) of the silica microparticles from which the MEK had been removed were weighed into a sample bottle and stirred for 10 minutes using an ultrasonic disperser (high-powered ultrasonic disperser for laboratory use, UP200S, manufactured by Hielscher) to prepare curable resin composition B. To 100 parts by mass of the obtained curable resin composition B, 2 parts by mass of a photopolymerization initiator (2-hydroxy-2-methylpropiophenone, manufactured by Tokyo Chemical Industry Co., Ltd.) was added and stirred. Next, using an applicator, the composition was applied to the surface of a PET film (MRE75T302, manufactured by Mitsubishi Chemical Corporation), and the resulting film was sandwiched between two PET films (MRE75T302). Next, ultraviolet light was irradiated using a UV irradiation device (manufactured by Quark Technology Co., Ltd.) to photopolymerize and harden the curable resin composition B, producing an elastomer layer with a thickness of 200 μm.

[0149] [ka]

[0150] Example 3 A film 10 of Example 3 consisting of a substrate 30, an adhesive layer 40, and an elastomer layer 11 was produced in the same manner as in Example 1, except that the preparation of the elastomer layer in Example 1 was changed as follows.

[0151] <Preparation of elastomer layer> 50 parts by weight of acrylic monomer (Light Acrylate POB-A) and 50 parts by weight of silica fine particles (Houtform® Silbol-C M220, manufactured by Fuji Chemical Co., Ltd.) were weighed into a sample bottle and stirred for 10 minutes using an ultrasonic disperser (High-Powered Ultrasonic Disperser for Laboratory Use, manufactured by Hielscher) to prepare curable resin composition C. 2 parts by weight of a photopolymerization initiator (2-hydroxy-2-methylpropiophenone, manufactured by Tokyo Chemical Industry Co., Ltd.) were added to 100 parts by weight of the resulting curable resin composition C and stirred. The resulting composition was then applied to the surface of a PET film (MRE75T302, manufactured by Mitsubishi Chemical Corporation) using an applicator, and sandwiched between two PET films (MRE75T302). The curable resin composition C was then photopolymerized and cured using a UV irradiation device (manufactured by Quark Technology Co., Ltd.) to produce a single elastomer layer with a thickness of 200 μm.

[0152] Example 4 Curable resin composition A was prepared in the same manner as in Example 1. To 100 parts by mass of curable resin composition A, 2 parts by mass of a photopolymerization initiator (2-hydroxy-2-methylpropiophenone, manufactured by Tokyo Chemical Industry Co., Ltd.) was added and stirred. The mixture was then applied to the surface of a substrate (polyethylene film, Lumirror (registered trademark), #75-QV22, 75 μm thick, manufactured by Toray Industries, Inc.) using an applicator, and sandwiched between PET films (MRE75T302). Next, ultraviolet light was irradiated using a UV irradiation device (manufactured by Quark Technology Co., Ltd.) to photopolymerize and harden the curable resin composition A. The PET film was then peeled off from the elastomer layer, producing film 10 of Example 4, which is shown in FIG. 5A and consists of substrate 30 and 200 μm-thick elastomer layer 11.

[0153] Example 5 A film 10 of Example 5, which consisted of a substrate 30 and an elastomer layer 11 having a thickness of 200 μm, was produced in the same manner as in Example 4, except that the curable resin composition A in Example 4 was changed to curable resin composition B prepared in the same manner as in Example 2.

[0154] Example 6 A film 10 of Example 6, which consisted of a substrate and a 200 μm-thick elastomer layer, was produced in the same manner as in Example 4, except that the curable resin composition A in Example 4 was changed to the curable resin composition C prepared in the same manner as in Example 3.

[0155] Example 7 A film 10 of Example 7, which was composed of a substrate 30, an adhesive layer 40, and a 200 μm-thick elastomer layer 11, was produced in the same manner as in Example 1, except that in laminating the substrate in Example 1, the substrate (polyethylene film, Lumirror (registered trademark), #75-QV22, thickness 75 μm, Toray Industries, Inc.) was changed to a polycarbonate film (3-8902-01, thickness 100 μm, manufactured by AS ONE Corporation) (hereinafter, sometimes abbreviated as "PC").

[0156] Example 8 A film 10 of Example 8, which was composed of a substrate 30 and an elastomer layer 11 having a thickness of 200 μm, was produced in the same manner as in Example 4, except that the substrate (polyethylene film, Lumirror (registered trademark), #75-QV22, thickness 75 μm, Toray Industries, Inc.) in Example 4 was changed to a polycarbonate film (3-8902-01, thickness 100 μm, manufactured by AS ONE Corporation).

[0157] (Comparative Example 1) A film of Comparative Example 1 consisting of a substrate, an adhesive layer, and an elastomer layer was produced in the same manner as in Example 1, except that the elastomer layer produced in Example 1 was changed to a urethane sheet (urethane gel, PS05, thickness 500 μm, manufactured by AS ONE Corporation).

[0158] (Comparative Example 2) A film of Comparative Example 2 consisting of a substrate, an adhesive layer, and an elastomer layer was produced in the same manner as in Example 1, except that the elastomer layer produced in Example 1 was changed to a thermoplastic polyurethane film (thermoplastic elastomer film, Esmer USR PX98, thickness 150 μm, manufactured by Nippon Matai Co., Ltd.).

[0159] (Comparative Example 3) A film of Comparative Example 3 consisting of a substrate, an adhesive layer, and an elastomer layer was produced in the same manner as in Example 1, except that the elastomer layer produced in Example 1 was changed to a polyethylene film (Polyfilm, HC0110, thickness 120 μm, manufactured by Iwatani Materials Corporation).

[0160] <Evaluation> The films of Examples 1 to 8 and Comparative Examples 1 to 3 were evaluated for the "stress relaxation rate" of the elastomer layer, as well as the "curl value," "linear transmittance," and "whiteness" of the film by the following methods. The results are shown in Table 1 below.

[0161] <<Stress relaxation rate>> The stress relaxation rate was evaluated by the following method using only the elastomer layer of the films of Examples 1 to 8 and Comparative Examples 1 to 3. Note that, in Examples 4 to 6 and Example 8, instead of the substrate, the elastomer layer was sandwiched between two PET films (MRE75T302) to prepare only the elastomer layer having a thickness of 200 μm, which was used as the measurement sample.

[0162] The elastomer layer was cut into strips measuring 10 mm long and 30 mm wide, with at least one direction being the length direction. These strips were stretched in the length direction at a rate of 200 mm / min using a tensile tester (microscope stretching stage, model: 10073, manufactured by Linkam Corporation) at a temperature of 25°C and a relative humidity of 45% at a stretching rate of 200 mm / min until they reached an elongation of 50% and were then stopped. The stress value of the elastomer layer was continuously measured from the start of stretching until 30 seconds after the stretching was stopped. The stress value that showed the highest stress within the measurement time was designated "A" (N), and the stress value 30 seconds after the stretching was stopped was designated "B" (N). The stress relaxation rate (%) of the elastomer layer was calculated according to the following formula 1. [Formula 1] Stress relaxation rate (%) = (AB) / A × 100

[0163] <<Curl value>> FIG. 1 is a schematic diagram illustrating a method for measuring the curl value of a film. A strip-shaped test piece measuring 10 mm in length and 30 mm in width was obtained by cutting the film with at least one direction as the length direction. This strip-shaped test piece was heated to 150°C using a tensile tester (microscope stretching stage, model: 10073, manufactured by Linkam Corporation). After reaching 150°C, it was left to stand for 10 seconds. It was then pulled in the length direction at a tensile speed of 200 mm / min in an environment of 150°C and 45% relative humidity, stretched (elongated) to an elongation of 20%, and then stopped. The temperature was then lowered to 40°C to obtain a molded product 10a. The film molded product 10a was placed on a horizontal table 20, and a ruler was placed perpendicular to the horizontal table 20. The lengths from the horizontal table to four points (points A, B, C, and D), which were the ends of the molded product 10a in a side view, were measured. The average of the lengths at the four points was calculated and used as the "curl value." A curl value of 1.8 mm or less was judged to be usable.

[0164] <<In-line transmittance for near-infrared rays>> FIG. 3 is a schematic diagram showing a method for measuring linear transmittance for near-infrared light. A UV-visible-near-infrared spectrophotometer (UH4150, manufactured by Hitachi High-Tech Science Corporation) was used as a spectroscope, and linear transmittance for near-infrared light at a wavelength of 940 nm was measured by the following method. A square test piece measuring 30 mm in length and 30 mm in width was cut out from the film, with at least one direction as the length direction. The test piece as film 10 was placed at a distance d of 20 cm from the opening of integrating sphere 32, and measurements were made. The transmitted light I obtained at this time was i The percentage of the intensity of the incident light I0 was calculated as the linear transmittance. The diameter D of the aperture was 1.8 cm, which corresponds to a solid angle of 0.025 sr.

[0165] <<Whiteness>> Using a spectrophotometer (CM-2600-D, manufactured by Konica Minolta Japan, Inc.), measurements were taken using a standard light source of D65, and the L * The value of L * The value of 0.01 was taken as the whiteness of the backscattered light of the film.

[0166] [Table 1] In Table 1, "*1" indicates an item that only relates to Examples 1 to 8.

[0167] Comparing Examples 1 to 8 with Comparative Examples 1 to 3, the films of Examples 1 to 8, in which the stress relaxation rate of the elastomer layer was 70% or more, had low curl values ​​and were able to suppress warpage of the film. Furthermore, the films of Examples 1 to 8 also had high whiteness and linear transmittance to near-infrared light.

[0168] The present invention includes, for example, the following aspects. <1> an elastomer layer on a substrate; The film is characterized in that the stress relaxation rate of the elastomer layer in at least one direction is 70% or more as calculated by the following formula 1: [Method for measuring stress relaxation rate] The elastomer layer is cut into a strip of 10 mm long x 30 mm wide, with at least one direction being the length direction. This strip of test piece is stretched in the length direction using a tensile tester at a tension speed of 200 mm / min in an environment of 25°C and 45% relative humidity, and is stretched to an elongation of 50% and then stopped. The stress value of the elastomer layer is continuously measured from the start of tension until 30 seconds after the stretching is stopped. The stress value that shows the highest stress within the measurement time is defined as "A" (N), and the stress value 30 seconds after the stretching is stopped is defined as "B" (N), and the stress relaxation rate (%) of the elastomer layer is calculated according to the following formula 1. [Formula 1] Stress relaxation rate (%) = (AB) / A × 100 <2> The adhesive layer is further provided between the substrate and the elastomer layer. <1> The film is described in <3> The optical filter <1> or <2> The film is described in <4> The elastomer layer has a linear transmittance of 45% or more for near-infrared rays. <1> from <3> The film is any one of the above. <5> The L measured using the SCE method with a spectrophotometer on the elastomer layer * The value of is 75 or more, <1> from <4> The film is any one of the above. <6> The elastomer layer contains a matrix and fine particles dispersed in the matrix. <1> from <5> The film is any one of the above. <7> The fine particles constitute at least a colloidal amorphous aggregate. <6> The film is described in <8> a device having a near-infrared light receiving unit; The device is provided with a near-infrared light receiving unit. <1> from <7> a film according to any one of the above items; The optical module is characterized by having: <9> The device is a sensing device, a communication device, a solar cell, a heater, or a power supply device. <8> 2. The optical module according to claim 1, wherein: <10> The aforementioned <1> from <7> The present invention is a method for producing a molded article, characterized in that the film according to any one of the above items is processed into a predetermined shape.

[0169] As described above, the present invention has been described based on specific embodiments and examples, but these embodiments and examples are presented merely as examples, and the present invention is not limited to the above embodiments and examples. The above embodiments can be embodied in various other forms, and various combinations, omissions, substitutions, additions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are also included in the inventions described in the claims and their equivalents. [Industrial Applicability]

[0170] The film according to the embodiment of the present invention can be used, for example, as an infrared transmission filter used in sensor technology or communication technology, a solar cell, a heater using infrared rays, an optically powered device using infrared rays, and the like. [Explanation of symbols]

[0171] 10...film 11... Elastomer layer 12... Matrix 14 … Fine particles 10a ... Molded body 20...Level platform 30 … Base material 32 … Integrating sphere 40, 40a, 40b, 40c…adhesive layer 41...Color filter layer 42...printed layer I0… Incident light I i … Transmitted light S b …backscattered light S f …Forward scattered light R i … Interface reflected light D: diameter of opening d … distance

Claims

1. an elastomer layer on a substrate; A film characterized in that the stress relaxation rate in at least one direction of the elastomer layer is 70% or more as calculated by the following formula 1: [Method for measuring stress relaxation rate] The elastomer layer is cut into a strip of 10 mm long x 30 mm wide, with at least one direction being the length direction, and the strip is pulled in the length direction at a tension speed of 200 mm / min in a tensile tester under an environment of 25°C and 45% relative humidity until it reaches an elongation of 50% and is stopped. The stress value of the elastomer layer is measured continuously from the start of tension until 30 seconds after the tension has stopped. The stress value that shows the highest stress within the measurement time is designated as "A" (N), and the stress value 30 seconds after the tension has stopped is designated as "B" (N), and the stress relaxation rate (%) of the elastomer layer is calculated based on the following formula 1: [Formula 1] Stress relaxation rate (%) = (A - B) / A x 100

2. The film of claim 1 further comprising an adhesive layer between the substrate and the elastomer layer.

3. The film of claim 1 which is an optical filter.

4. The film according to claim 1 , wherein the elastomer layer has an in-line transmittance for near-infrared light of 45% or more.

5. The L of the elastomer layer was measured using a spectrophotometer in the SCE method. ＊ 2. The film of claim 1, wherein the value of .gtoreq..times ...

6. The film of claim 1 , wherein the elastomeric layer comprises a matrix and particulates dispersed in the matrix.

7. The film of claim 6 , wherein the particulates comprise at least a colloidal amorphous aggregate.

8. a device having a near-infrared light receiving unit; The film of claim 1 disposed in front of the near-infrared receiving portion of the device; An optical module comprising:

9. The optical module according to claim 8 , wherein the device is a sensing device, a communication device, a solar cell, a heater, or a power supply device.

10. A method for producing a molded article, comprising processing the film according to claim 1 into a predetermined shape.

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