Polarizing film protective film, polarizing sheet, heat-bent molded body, sunglasses, method for manufacturing polarizing film protective film, and method for manufacturing heat-bent molded body

Abstract

To provide a polarizing film protective film, a polarizing sheet, a heat-bent molded body, sunglasses, a method for manufacturing a polarizing film protective film, and a method for manufacturing a heat-bent molded body, which can provide a polarizing sheet that maintains high retardation even with a thin thickness, and in which the curves in the X direction and Y direction of the sheet surface during heat bending are easily aligned. [Solution] The polarizing protective film according to this disclosure is a polarizing protective film comprising an amorphous or microcrystalline polyamide resin, wherein the retardation (Re) of the polarizing protective film is 3000 nm or more and 5000 nm or less, the center line between the two sides of the film is defined as direction E1 as being nearly parallel to the slow-moving axis direction determined when the retardation (Re) of the polarizing protective film is measured, the deviation of the slow-moving axis at the center of the polarizing protective film and the deviation of the slow-moving axis from direction E1 at a position 20 mm toward the center line from both sides of the polarizing protective film are both less than ±2.0°, and the thickness (T1) of the polarizing protective film is 150 μm or more and 270 μm or less.

Description

[Technical Field]

[0001] The present invention relates to a polarizing film protective film, a polarizing sheet, a heat-bent molded article, sunglasses, a method for manufacturing a polarizing film protective film, and a method for manufacturing a heat-bent molded article. In particular, this relates to polarizing film protective films containing amorphous or microcrystalline polyamide resins. [Background technology]

[0002] Currently, polarizing sheets in practical use typically utilize a polarizing film made by adsorbing or impregnating polyvinyl alcohol (PVA) with iodine or a dichroic organic dye. This polarizing film is usually protected on one or both sides by a transparent resin such as triacetylcellulose, resulting in a polarizing sheet (sometimes called a polarizing plate) that is easy to handle, suitable for secondary processing, inexpensive, and lightweight.

[0003] In this case, when the polarizing sheet is used in applications requiring impact resistance, such as polarizing lenses for sunglasses, a polarizing film made with a dichroic organic dye is laminated with a polarizing film protective film (sometimes called a polarizing film substrate), such as a polycarbonate film, on both sides to form a polarizing sheet. This sheet is then punched into the desired shape, partially heat-bent into a spherical shape, and subjected to appropriate surface treatment. As an example of a polarizing sheet for such heat bending processes, the one described in Patent Document 1 is known. On the other hand, when lenses made of polycarbonate film are used in eyeglass frames made of plasticizers such as cellulose acetate, problems have been pointed out such as the plasticizer in the eyeglass frame bleeding out and causing cracks in the polycarbonate lens. In light of these circumstances, polarizing sheets made by stretching polyamide resin film to impart retardation and using them as protective films are being considered (Patent Document 2).

[0004] Furthermore, Patent Document 3 discloses a polarizing laminate characterized in that a protective function portion is arranged on one side of a linear polarization function portion and a thermal bonding function portion is arranged on the other side, wherein the linear polarization function portion is a linear polarizer, the protective function portion is either a cast-molded sheet, a stretch-oriented sheet, or an extruded sheet with a thickness of 0.25 mm or less, and the thermal bonding function portion is an extruded thermal bonding sheet.

[0005] Furthermore, Patent Document 4 discloses a polarizing laminate comprising a polarizing film made of a uniaxially stretched polyvinyl alcohol-based resin film, with transparent plastic sheets arranged as protective layers on both sides via adhesive layers, wherein, in terms of optical distortion measured according to MIL-DTL-43511D, the difference between the maximum and minimum widths of the gaps between two adjacent slits in the polarizing laminate (slit spacing) is 1.05 mm or less. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2003-145616 [Patent Document 2] Japanese Patent Publication No. 2020-52406 [Patent Document 3] Japanese Patent Publication No. 2011-180266 [Patent Document 4] Japanese Patent Publication No. 2024-13669 [Overview of the project] [Problems that the invention aims to solve]

[0007] As mentioned above, polarizing sheets using polyamide resin films are being considered. On the other hand, in recent years there has been a growing demand for thinner polarizing sheets. The inventors' investigations revealed that as the polyamide resin film used for the polarizing sheet becomes thinner, it becomes difficult to achieve high retardation, and problems such as the uneven curvature of the X-direction and Y-direction of the polarizing sheet surface during heat bending become more likely to occur, making it easier for the heat-bent polarizing sheet to detach from the injection mold during the lensing process. However, this point is not addressed at all in the aforementioned patent document. The present invention aims to solve the above problems and to provide a polarizing film protective film, a polarizing sheet, a heat-bent molded article, sunglasses, a method for manufacturing a polarizing film protective film, and a method for manufacturing a heat-bent molded article, which can provide a polarizing sheet that exhibits high retardation even when thin and in which the curves in the X direction and Y direction of the sheet surface are easily aligned during heat bending. [Means for solving the problem]

[0008] Based on the above problems, the inventors conducted studies and found that the above problems were solved by the following means. [1] A polarizing protective film comprising an amorphous or microcrystalline polyamide resin, The retardation (Re) of the polarizing protective film is between 3000 nm and 5000 nm. When the center line between the two sides of the polarizing protective film, which is nearly parallel to the slow-moving axis determined during measurement of the retardation (Re) of the polarizing protective film, is defined as direction E1, The deviation of the slow axis at the center of the polarizing protective film, and the slow axis at positions 20 mm toward the center line from both sides of the polarizing protective film, from direction E1 is less than ±2.0°. A polarizing film protective film having a thickness (T1) of 150 μm or more and 270 μm or less. [2] A polarizing protective film comprising an amorphous or microcrystalline polyamide resin, The retardation (Re) of the polarizing protective film is between 3000 nm and 5000 nm. When the side of the polarizing protective film that is closest to being parallel to the slow-moving axis direction, which is determined when the retardation (Re) of the polarizing protective film is measured, is defined as the stretching direction E2, The deviation of the slow-moving axis at the center of the polarizing protective film, and the deviation of the slow-moving axis at a position 20 mm from each end of the polarizing protective film, from the stretching direction E2 is less than ±2.0° in both cases. A polarizing film protective film having a thickness (T1) of 150 μm or more and 270 μm or less. [3] The polarizing film protective film according to [1] or [2], wherein the amorphous or microcrystalline polyamide resin comprises a polyamide resin containing alicyclic diamine units and aliphatic dicarboxylic acid units having 7 to 20 carbon atoms. [4] The polarizing film protective film according to [3], wherein the alicyclic diamine unit comprises at least one represented by formula (PA-0). [ka] (In formula (PA-0), R is an independent substituent, and n is an independent integer between 0 and 5. L is a single bond or a divalent linking group. * indicates a bond site with another unit or terminal group.) [5] The polarizing film protective film according to any one of [1] to [4], wherein the thickness (T1) of the polarizing film protective film is 180 to 270 μm. [6] The polarizing film protective film according to any one of [1] to [5], wherein the polarizing film protective film is a uniaxially oriented film. [7] The polarizing film protective film according to any one of [1] to [6], wherein the length of the long side of the polarizing film protective film is 300 mm or more, and the length of the short side of the polarizing film protective film is 290 mm or more. [8] The amorphous or microcrystalline polyamide resin includes a polyamide resin comprising alicyclic diamine units and aliphatic dicarboxylic acid units having 7 to 20 carbon atoms, The alicyclic diamine unit includes at least one represented by formula (PA-0), The thickness (T1) of the polarizing protective film is 180 to 270 μm. The polarizing film protective film is a uniaxially stretched film, the long side length of the polarizing film protective film is 300 mm or more, and the short side length of the polarizing film protective film is 290 mm or more. The polarizing film protective film according to any one of [1] to [7]. [Chemical formula] (In formula (PA-0), each R is independently a substituent, each n is independently an integer from 0 to 5. L is a single bond or a divalent linking group. * is a bonding site with another unit or terminal group.) [9] The haze of the polarizing film protective film measured according to JIS K 7136 is less than 1.0%. The polarizing film protective film according to any one of [1] to [8].

[10] A polarizing sheet having a first polarizing film protective film, a polarizing film, and a second polarizing film protective film in that order, where the first polarizing film protective film is the polarizing film protective film according to any one of [1] to [9].

[11] A polarizing sheet having a first polarizing film protective film, a polarizing film, and a second polarizing film protective film in that order, The first polarizing film protective film contains an amorphous or microcrystalline polyamide resin, the retardation (Re) of the first polarizing film protective film is 3000 nm or more and 5000 nm or less, when the center line between both sides of the film that is in a nearly parallel relationship with the slow axis direction determined at the time of measuring the retardation (Re) of the polarizing film protective film is defined as direction E1, the deviation of the slow axis phase at the center of the polarizing film protective film and the slow axis at positions 20 mm from both sides of the polarizing film protective film toward the center line from direction E1 is both less than ±2.0°, when the side of the film that is in the closest parallel relationship with the slow axis direction determined at the time of measuring the retardation (Re) of the polarizing film protective film is defined as the stretching direction E2, The retardation axes at the center of the polarizing film protective film and the retardation axes at positions 20 mm from both ends of the polarizing film protective film are both less than ±2.0° from the stretching direction E2. The thickness (T1) of the first polarizing film protective film is 150 μm or more and 270 μm or less. A polarizing sheet in which the ratio (T1 / T2) of the thickness (T1) of the first polarizing film protective film to the thickness (T2) of the second polarizing film protective film satisfies 1.0 < T1 / T2 < 1.67.

[12] The polarizing sheet according to

[10] or

[11] , wherein the total thickness of the polarizing sheet is 270 μm or more and 535 μm or less.

[13] A thermally bent molded body of the polarizing sheet according to any one of

[10] to

[12] .

[14] The thermally bent molded body according to

[13] , wherein the first polarizing film protective film side is a curved convex surface and the second polarizing film side is a curved concave surface.

[15] Sunglasses including the polarizing sheet according to any one of

[10] to

[12] .

[16] A polarizing film protective film containing an amorphous or microcrystalline polyamide resin, wherein the retardation (Re) of the polarizing film protective film is 3000 nm or more and 5000 nm or less. When the center line between both sides of the film that is in a nearly parallel relationship with the retardation axis direction determined during the measurement of the retardation (Re) of the polarizing film protective film is defined as the direction E1. The deviation of the slow axis at the center of the polarizing film protective film and the deviation of the retardation axes at positions 20 mm from both sides of the polarizing film protective film toward the center line from the direction E1 are both less than ±2.0°. When the side of the film that is in the closest parallel relationship with the retardation axis direction determined during the measurement of the retardation (Re) of the polarizing film protective film is defined as the stretching direction E². The deviation of the retardation axis at the center of the polarizing film protective film and the deviation of the retardation axes at positions 20 mm from both ends of the polarizing film protective film from the stretching direction E2 are both less than ±2.0°. A method for manufacturing a polarizing film protective film, wherein the thickness (T1) of the polarizing film protective film is 150 μm or more and 270 μm or less, A method for manufacturing a polarizing film protective film, comprising uniaxial stretching of a polyamide resin film containing an amorphous or microcrystalline polyamide resin, wherein the stretching ratio is greater than 0 and less than or equal to 1.9 times.

[17] A method for manufacturing a polarizing film protective film according to

[16] , wherein the stretching booth temperature during stretching is in the range of Tmg-15°C to Tmg+17°C, with respect to the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin.

[18] A method for manufacturing a polarizing film protective film according to

[16] or

[17] , wherein the surface temperature of the stretching roll immediately before stretching during stretching is in the range of Tmg-15°C to Tmg-5°C, with respect to the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin.

[19] A method for manufacturing a polarizing film protective film according to any one of

[16] to

[18] , wherein the polarizing film protective film is the polarizing film protective film according to any one of [1] to [9].

[20] The stretching booth temperature during stretching is in the range of Tmg-15°C to Tmg+17°C, with reference to the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin. The surface temperature of the stretching roll immediately before stretching during the stretching process is in the range of Tmg-15°C to Tmg-5°C, with respect to the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin. A method for manufacturing a polarizing film protective film according to any one of

[16] to

[19] , wherein the polarizing film protective film is the polarizing film protective film according to any one of [1] to [9]. A method for manufacturing a hot-bent molded article, comprising hot-bending a polarizing sheet described in any one of

[21]

[10] to

[12] at a temperature of Tmg-12°C to Tmg-6°C, with reference to the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin contained in the first polarizing film protective film. [Effects of the Invention]

[0009] The present invention provides a polarizing film protective film, a polarizing sheet, a heat-bent molded article, sunglasses, a method for manufacturing a polarizing film protective film, and a method for manufacturing a heat-bent molded article, which can provide a polarizing sheet that exhibits high retardation even with a thin thickness and in which the curves in the X direction and Y direction of the sheet surface are easily aligned during heat bending. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing a method for manufacturing a polarizing protective film. [Figure 2] This is a schematic diagram illustrating an example of the layer structure of a heat-bent molded body. [Figure 3] This is a schematic diagram illustrating the method for measuring the deviation of the slow-moving axis of the polarizing protective film from directions E1 and E2 in the embodiment. [Modes for carrying out the invention]

[0011] The following describes in detail embodiments for carrying out the present invention (hereinafter simply referred to as "this embodiment"). Note that the following embodiment is illustrative for explaining the present invention, and the present invention is not limited to this embodiment. In this specification, "~" is used to mean that the numbers before and after it are included as the lower and upper limits. "A~B" means that it is greater than or equal to A and less than or equal to B. Furthermore, the upper and lower limits of the numerical values ​​in this specification are given as examples of this embodiment, regardless of the combination of upper and lower limits.

[0012] In this specification, a preferred combination of embodiments is a more preferred embodiment. In this specification, all physical properties and characteristic values ​​shall be those at 23°C unless otherwise specified. In this specification, "film" and "sheet" refer to molded articles that are thin in thickness relative to their length and width, and are generally flat. Furthermore, "film" and "sheet" in this specification may each be single-layered or multi-layered. An example of a film is single-layered, and an example of a sheet is multi-layered (e.g., 3 to 10 layers). In this embodiment, the film and sheet are usually rectangular (square). The term "rectangular" includes not only a rectangular shape in the geometric sense, but also shapes that are generally considered rectangular in the technical field of the present invention (e.g., a rolled-up material). If the measurement methods, etc., described in the standards shown in this specification differ from year to year, unless otherwise specified, the standards as of January 1, 2024 shall apply. If the measurement methods, etc., described in the standards shown in this specification have been discontinued as of January 1, 2024, the standards in effect at the time of discontinuation shall apply. Figures 1 and 2 may not accurately reflect reality in terms of scale and other factors.

[0013] <Polarizing protective film> The polarizing film protective film of this embodiment is a polarizing film protective film comprising an amorphous or microcrystalline polyamide resin, wherein the retardation (Re) of the polarizing film protective film is 3000 nm or more and 5000 nm or less. (1) When the retardation (Re) of the polarizing protective film is measured, the slow axis direction is determined, and the center line between the two sides of the film, which is nearly parallel to the slow axis direction, is defined as direction E1. The deviations of the slow axis at the center of the polarizing protective film, and the slow axis at positions 20 mm from each side of the polarizing protective film toward the center line, from direction E1 are both less than ±2.0°. (2) When the side of the film that is closest to being parallel to the slow-moving axis determined when measuring the retardation (Re) of the polarizing protective film is defined as the stretching direction E2, the deviation of the slow-moving axis at the center of the polarizing protective film and the slow-moving axis at positions 20 mm from both ends of the polarizing protective film from the stretching direction E2 is less than ±2.0° in both cases. The polarizing protective film is characterized by having a thickness (T1) of 150 μm or more and 270 μm or less. By adopting this configuration, it becomes possible to provide a polarizing protective film that exhibits high retardation even with a thin thickness, and that makes it easier to align the curves in the X and Y directions of the sheet surface during heat bending. Polarizing protective films require high retardation (Re). This is necessary, for example, to ensure the functionality of sunglasses. To achieve such high retardation (Re), stretching the polarizing protective film is a possible solution. The higher the stretching ratio, the easier it is for the polarizing protective film to exhibit high retardation (Re). However, the inventors' investigations revealed that in films containing a thin polyamide resin, increasing the stretching ratio makes the film more prone to tearing, and also makes it difficult to align the curves in the X and Y directions of the sheet surface during heat bending. In particular, it was found that when the thickness of the polarizing film protective film or the polarizing sheet containing the polarizing film protective film is thin, it becomes difficult to align the curves in the X and Y directions of the sheet surface during heat bending. Furthermore, in the case of thin polarizing sheets, if the curves in the X direction and Y direction of the sheet surface are to be aligned during heat bending, the heat bending temperature becomes high. From the viewpoint of the performance of polyamide resin, it is desirable that the heat bending temperature be below the glass transition temperature Tmg-4°C, and even more preferably between the glass transition temperature Tmg-12°C and Tmg-4°C. In addition, given the actual conditions of heat bending machines, there is a strong requirement for the heat bending temperature to be below 145°C, and it is desirable that it be performed at a temperature of around 142°C ± 3°C. On the other hand, the above issue is less of a problem with thicker films, as high retardation can be achieved even with lower stretching ratios.

[0014] Furthermore, the polarizing protective film of this embodiment can effectively suppress light leakage. More specifically, by reducing the aforementioned slow-moving axis misalignment, it is possible to provide a polarizing protective film that has high retardation even with a thin thickness and suppresses light leakage throughout the entire film.

[0015] Under these circumstances, in this embodiment, a film has been found that is thin and has small deviations in the slow axis at the edges and center of the film, thereby achieving high retardation (Re) and good thermal bending processability as a polarizing film protective film. In other words, when a film is stretched (especially uniaxially), the shift in the slow axis at the edges of the polarizing protective film usually becomes large. When such a polarizing protective film is heat-bent, differences appear in the curve values ​​in the longitudinal direction (the X direction of the film surface, more specifically the direction in which the film is formed, stretched, and laminated) and the width direction (the Y direction of the film surface, more specifically the width direction perpendicular to the direction in which the film is formed, stretched, and laminated). Therefore, in this embodiment, by precisely adjusting the stretching conditions, it is possible to provide a polarizing protective film that exhibits high retardation even with a thin thickness, and that makes it easy to align the curves in the X direction and Y direction of the sheet surface during heat bending.

[0016] The embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is merely one example of an embodiment of the present invention and is not limited to these.

[0017] The polarizing protective film of this embodiment has a retardation (Re) of 3000 nm to 5000 nm. By having such a high retardation (Re), it can be used effectively as a polarizing sheet. The retardation (Re) is preferably 3400 nm or higher, and may also be 4500 nm or lower, or 4000 nm or lower.

[0018] In this embodiment, when the center line between the two sides of the polarizing protective film, which is nearly parallel to the slow-moving axis determined when measuring the retardation (Re) of the polarizing protective film, is defined as direction E1, the deviation from direction E1 of the slow-moving axis at the center of the polarizing protective film, and the slow-moving axis at a position 20 mm toward the center line from both sides of the polarizing protective film, is less than ±2.0° in both cases. When the retardation (Re) of the polarizing protective film is measured, the side of the film that is closest to being parallel to the slow-moving axis is defined as the stretching direction E2. In this case, the deviation from the stretching direction E2 of the slow-moving axis at the center of the polarizing protective film, and the slow-moving axis at positions 20 mm from both ends of the polarizing protective film, is less than ±2.0°. Figure 3 is a schematic diagram illustrating the method for measuring the deviation of the polarizing protective film from the direction E1 and the stretching direction E2 of the slow-moving axis, as described in the embodiment later. This will be used as an example for explanation. In other words, the slow-moving axis direction (hereinafter referred to as the slow-moving axis direction Dr) determined during the measurement of the retardation (Re) of the polarizing protective film refers to the slow-moving axis direction that is simultaneously output during the measurement of the retardation (Re) of the polarizing protective film. This direction generally or completely coincides with the direction of the central arrow in Figure 3. Direction E1 is the center line of both sides of the film (L and R in Figure 3) which is nearly parallel to the slow-moving axis direction Dr. On the other hand, the stretching direction E2 is the direction of the side of the film (L or R in Figure 3) that is closest to being parallel to the slow-moving axis direction Dr. Since the film is rectangular, direction E1 and the stretching direction E2 are usually the same.

[0019] In this embodiment, the deviation of the slow axis in the center of the polarizing protective film with respect to the direction E1 and / or the stretching direction E2 is less than ±2.0°, preferably less than ±1.5°, more preferably less than ±1.1°, and even more preferably less than ±0.8°. Furthermore, in this embodiment, the deviation of the slow axis at positions 20 mm toward the center line from both sides of the polarizing protective film (L1 and R1 in Figure 3) with respect to the direction E1 and / or the stretching direction E2 is preferably less than ±2.0°, preferably less than ±1.5°, and more preferably less than ±0.9°. By setting the deviation of the slow axis at the center of the polarizing protective film and the slow axis at positions 20 mm toward the center line from both sides of the polarizing protective film to the above range, the curves in the X direction and Y direction of the sheet surface tend to align more easily during heat bending. In addition, by setting the deviation of the slow axis at the center of the polarizing protective film and the slow axis at positions 20 mm toward the center line from both sides of the polarizing protective film to the above range, light leakage when the polarizing sheet is heat-bent tends to be further suppressed.

[0020] The thickness (T1) of the polarizing protective film in this embodiment is 150 μm or more, preferably 165 μm or more, more preferably 180 μm or more, even more preferably 190 μm or more, even more preferably 200 μm or more, even more preferably 205 μm or more, and also 270 μm or less, can be 250 μm or less, and can even be 245 μm or less. Setting the thickness (T1) of the polarizing protective film to be above the lower limit tends to increase the retardation (Re). Also, setting the thickness (T1) of the polarizing protective film to be below the upper limit tends to make the curves in the X direction and Y direction of the sheet surface more aligned during heat bending.

[0021] The retardation (Re), phase shift, and thickness of the polarizing protective film are measured according to the description in the examples below (the same applies to the second polarizing protective film).

[0022] As described above, in order to obtain a polarizing protective film with high retardation (Re), small phase axis misalignment, and thin thickness, examples include combining two or more of the following methods. (1) To stretch a resin film containing amorphous or microcrystalline polyamide resin at a low stretch ratio while achieving a thin thickness and high retardation (Re). (2) Uniaxially stretching a resin film containing an amorphous or microcrystalline polyamide resin. (3) When stretching resin films containing amorphous or microcrystalline polyamide resin, the stretching temperature (booth temperature or surface temperature of the stretching roll immediately before stretching) should be carefully controlled. These details will be described later in the section on the manufacturing method of the polarizing protective film.

[0023] The aforementioned Patent Document 3 does not consider booth temperature or roll temperature at all. Naturally, it also does not consider polarizing sheets that make it easier for the curves in the X direction and Y direction of the sheet surface to align during heat bending. Furthermore, the inventors' investigations revealed that the film described in the example of Patent Document 3 becomes cloudy due to its thickness and stretching ratio, resulting in a haze far exceeding 1.0%. On the other hand, while the film described in Patent Document 4 is a film with excellent optical distortion resistance, it does not consider polarizing sheets in which the curves in the X direction and Y direction of the sheet surface are easily aligned during heat bending. For example, in the film described in Example 7 of Patent Document 4, since the melt-extruded polyamide film is cut into 40 cm squares and then stretched in a batch manner, it is extremely difficult to adjust the deviation of the slow phase axis. In particular, it is extremely difficult to keep the deviation of the slow phase axis at the center of the polarizing film protective film, and the slow-moving axis at positions 20 mm toward the center line from both sides of the polarizing film protective film, from direction E1 to less than ±2.0° throughout the entire film.

[0024] Therefore, the polarizing film protective film of this embodiment may be a uniaxially oriented film or a biaxially oriented film, but it is preferably a uniaxially oriented film.

[0025] <<Amorphous or microcrystalline polyamide resin>> On the other hand, the polarizing film protective film of this embodiment contains an amorphous or microcrystalline polyamide resin. By including an amorphous or microcrystalline polyamide resin, a polarizing film protective film that is less susceptible to damage from plasticizers and other substances, and has excellent transparency, can be obtained.

[0026] Here, amorphous or microcrystalline polyamide resin refers to a resin that does not have a distinct melting point, specifically, one in which the enthalpy of fusion ΔHm is less than 5 J / g, preferably 3 J / g or less, and more preferably 1 J / g or less. The enthalpy of fusion ΔHm is measured in accordance with JIS K7121 and K7122, during the heating process. Specifically, the polyamide resin is heated from room temperature to 250°C at a heating rate of 10°C / min in a nitrogen stream using a differential scanning calorimeter (DSC), immediately cooled to below room temperature, and then heated again from room temperature to 250°C at a heating rate of 10°C / min. The above also applies to amorphous or microcrystalline thermoplastic resins other than amorphous or microcrystalline polyamide resins.

[0027] The amorphous or microcrystalline polyamide resin is not particularly defined in terms of its structure, but it is preferable that it includes a polyamide resin containing alicyclic diamine units and aliphatic dicarboxylic acid units having 7 to 20 carbon atoms.

[0028] In this embodiment, the alicyclic diamine constituting the alicyclic diamine unit is preferably a diamine containing a five-membered ring and / or a six-membered ring. The five-membered ring and / or six-membered ring may or may not have substituents. Furthermore, it is preferable that the alicyclic diamine consists only of aliphatic hydrocarbon groups containing an alicyclic structure, except for the terminal amino group. The alicyclic diamine unit contains, more preferably, two or more substituted or unsubstituted cyclohexane rings, and even more preferably, two substituted or unsubstituted cyclohexane rings. The alicyclic diamine unit preferably does not contain carbon-carbon double bonds or carbon-carbon triple bonds. The molecular weight of the alicyclic diamine constituting the alicyclic diamine unit is preferably 195 or more, more preferably 200 or more, preferably 500 or less, more preferably 400 or less, and even more preferably 300 or less.

[0029] In this embodiment, it is more preferable that the alicyclic diamine unit includes at least one represented by formula (PA-0). [ka] (In formula (PA-0), R is an independent substituent, and n is an independent integer between 0 and 5. L is a single bond or a divalent linking group. * indicates a bond site with another unit or terminal group.) In formula (PA-0), each R is independently a substituent, preferably an aliphatic group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, even more preferably a linear or branched alkyl group having 1 to 6 carbon atoms, even more preferably a methyl group, an ethyl group, or a propyl group, and even more preferably a methyl group. In formula (PA-0), n is an integer between 0 and 5, preferably an integer of 1 or more, preferably an integer of 4 or less, more preferably an integer of 3 or less, even more preferably an integer of 2 or less, and even more preferably an integer of 1 or less. In formula (PA-0), L is a single bond or a divalent linking group, more preferably a single bond or a divalent aliphatic hydrocarbon group, more preferably a single bond or a divalent alkylene group, even more preferably a single bond or an alkylene group having 1 to 3 carbon atoms, even more preferably a single bond, a methylene group, an ethylene group or an isopropylene group, and even more preferably a methylene group. * indicates a bonding site with another unit or terminal group. That is, it is usually bonded to -C(=O)- to form an amide bond with NH in formula (PA-0), or bonded to a hydrogen atom to form a terminal amino group with NH in formula (PA-0), or bonded to a terminal group.

[0030] In this embodiment, it is more preferable that the alicyclic diamine unit is represented by formula (PA-1). [ka] (In formula (PA-1), R 1 Each of these is an alkyl group having 1 to 5 carbon atoms, and each of these is an integer from 0 to 3. * indicates a bonding site with another unit or terminal group.

[0031] In formula (PA-1), R 1 This is an alkyl group having 1 to 5 carbon atoms, preferably a linear or branched alkyl group having 1 to 5 carbon atoms, more preferably a methyl group, an ethyl group, or a propyl group, and even more preferably a methyl group. In formula (PA-1), n1 is an integer between 0 and 3, preferably an integer of 1 or greater, preferably an integer of 2 or less, and more preferably 0 or 1. In equation (PA-1), the first example of n1 is 0. In equation (PA-1), the second example of n1 is 1. When n1 is 1, R 1 It is preferable that it be a methyl group.

[0032] Specific examples of alicyclic diamines include 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, bis(4-amino-3-methylcyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, 2,2-bis(4-amino-3-methylcyclohexyl)propane, bis(aminomethyl)decalin, and bis(aminomethyl)tricyclodecane.

[0033] Amorphous or microcrystalline polyamide resins contain alicyclic diamine units in a proportion of preferably 75 mol% or more, more preferably 80 mol% or more, even more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, particularly even more preferably 99 mol% or more, and 100 mol% or less of the total diamine units constituting the amorphous or microcrystalline polyamide resin. The alicyclic diamine units may be one type or a combination of two or more types.

[0034] Examples of diamines other than alicyclic diamines that can be used as raw material diamines for amorphous or microcrystalline polyamide resins include aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, and 2,4,4-trimethylhexamethylenediamine, as well as aromatic ring-containing diamines such as xylylenediamine, bis(4-aminophenyl) ether, paraphenylenediamine, and bis(aminomethyl)naphthalene. These can be used individually or in combination of two or more.

[0035] On the other hand, in this embodiment, the C7-C20 aliphatic dicarboxylic acid constituting the C7-C20 aliphatic dicarboxylic acid unit is preferably a C7-C20 linear or branched aliphatic dicarboxylic acid, more preferably a C7-C20 linear aliphatic dicarboxylic acid, and even more preferably an C7-C20 α,ω-linear aliphatic dicarboxylic acid. The number of carbon atoms in the C7-C20 aliphatic dicarboxylic acid (preferably a C7-C20 linear aliphatic dicarboxylic acid) is preferably 8 or more, more preferably 9 or more, even more preferably 10 or more, preferably 18 or less, more preferably 16 or less, even more preferably 14 or less, even more preferably 13 or less, and even more preferably 12 or less. The C7-C20 aliphatic dicarboxylic acid is HOOC-(CH2) n It is preferable to represent it as -COOH, where n is an integer between 5 and 18. The aliphatic dicarboxylic acid units having 7 to 20 carbon atoms that can be used in this embodiment preferably include at least one of sebacic acid units, undecanediic acid units, and dodecanediic acid units, and more preferably include sebacic acid units and / or dodecanediic acid units.

[0036] Amorphous or microcrystalline polyamide resins contain aliphatic dicarboxylic acid units having 7 to 20 carbon atoms in a proportion of preferably 75 mol% or more, more preferably 80 mol% or more, even more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, particularly even more preferably 99 mol% or more, and 100 mol% or less of the total dicarboxylic acid units constituting the polyamide resin. The aliphatic dicarboxylic acid units having 7 to 20 carbon atoms may be one type or a combination of two or more types.

[0037] Examples of dicarboxylic acids other than aliphatic dicarboxylic acids with 7 to 20 carbon atoms include phthalate compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid, as well as isomers of naphthalenedicarboxylic acids such as 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid. One or more of these can be used in combination.

[0038] The amorphous or microcrystalline polyamide resin used in this embodiment may further contain aminocarboxylic acid units. By including aminocarboxylic acid units, the hue of the resulting polarizing protective film can be further improved. There are no specific requirements for the type of aminocarboxylic acid that constitutes the aminocarboxylic acid unit; known aminocarboxylic acids can be used. In this embodiment, it is preferable that the aminocarboxylic acid is composed only of aliphatic hydrocarbon groups, except for the terminal amino group and carboxylic acid group. The molecular weight of the aminocarboxylic acid constituting the aminocarboxylic acid unit is preferably 180 or more, more preferably 190 or more, preferably 400 or less, more preferably 300 or less, and even more preferably 250 or less.

[0039] In this embodiment, the aminocarboxylic acid constituting the aminocarboxylic acid unit is preferably represented by formula (PA-2). [ka] (In equation (PA-2), n is an integer between 5 and 20.) In formula (PA-2), n is an integer between 5 and 20, preferably 6 or greater, more preferably 7 or greater, even more preferably 8 or greater, even more preferably 9 or greater, even more preferably 10 or greater, and also preferably 18 or less, more preferably 16 or less, even more preferably 14 or less, even more preferably 13 or less, and even more preferably 12 or less.

[0040] It should be noted that while amorphous or microcrystalline polyamide resins mainly contain diamine units and dicarboxylic acid units, they do not completely exclude other monomer units, and may also contain lactam units such as ε-caprolactam and laurolactam, and aliphatic aminocarboxylic acid units such as aminocaproic acid and aminoundecanoic acid. In particular, the amorphous or microcrystalline polyamide resin used in this embodiment may contain aminocarboxylic acid units. In this embodiment, it is preferable that the total mass of diamine units, dicarboxylic acid units, and optionally aminocarboxylic acid units among the monomer units constituting the amorphous or microcrystalline polyamide resin accounts for 90% by mass or more of the total monomer units, more preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 99% by mass or more. In amorphous or microcrystalline polyamide resins, the molar ratio of diamine units to dicarboxylic acid units is preferably 40:60 to 60:40, and more preferably 45:55 to 55:45. Furthermore, in this embodiment, the proportion of aminocarboxylic acid units among the total monomer units constituting the amorphous or microcrystalline polyamide resin is preferably 0 mol% or more, and may be greater than 0 mol%, and may be 1 mol% or more, 5 mol% or more, 10 mol% or more, and preferably 50 mol% or less, and may be 30 mol% or less, 20 mol% or less, 10 mol% or less, 5 mol% or less, 3 mol% or less, or 1 mol% or less, depending on the application. An example of an amorphous or microcrystalline polyamide resin used in this embodiment is a resin in which the proportion of aminocarboxylic acid units among the total monomer units constituting the polyamide resin is 10 to 20 mol%. Another example of an amorphous or microcrystalline polyamide resin used in this embodiment is a resin in which the proportion of aminocarboxylic acid units among the total monomer units constituting the polyamide resin is 5 mol% or less.

[0041] Amorphous or microcrystalline polyamide resins may also be made using polyamide resins produced from biomass raw materials (biomass polyamide resins). Using biomass polyamide resins can help reduce environmental impact. Amorphous or microcrystalline polyamide resins may also use monomer raw materials that have undergone Mass Balance Certification (ISCC PLUS). Mass Balance Certification means that the extent to which renewable or bio-based raw materials are used in each factory or production facility, and how much of the product is produced or shipped, is quantified and guaranteed along with quality. Furthermore, amorphous or microcrystalline polyamide resin may be recycled products (including recovered products, material recycled products, chemical recycled products, etc.), unsuitable products, or scraps generated during the molding of amorphous or microcrystalline polyamide resin or the polarizing film protective film of this embodiment.

[0042] The glass transition temperature Tmg (midpoint glass transition temperature) of the amorphous or microcrystalline polyamide resin in the polarizing film protective film of this embodiment is preferably 120°C or higher, more preferably 130°C or higher, even more preferably 140°C or higher, preferably 170°C or lower, more preferably 165°C or lower, and may also be 160°C or lower. If the polarizing protective film of this embodiment contains two or more amorphous or microcrystalline polyamide resins, the glass transition temperature Tmg is the Tmg of the mixture of amorphous or microcrystalline polyamide resins. The glass transition temperature Tmg is measured according to the example described below.

[0043] In the polarizing film protective film of this embodiment, the content of amorphous or microcrystalline polyamide resin is preferably 90% by mass or more, more preferably 94.5% by mass or more, and even more preferably 96% by mass or more, based on 100% by mass of the polarizing film protective film. By setting the content of amorphous or microcrystalline polyamide resin above the lower limit, the glass transition temperature Tmg tends to be higher. Furthermore, in the polarizing film protective film of this embodiment, the content of amorphous or microcrystalline polyamide resin is preferably 99.999% by mass or less, based on 100% by mass of the polarizing film protective film. By setting the content of amorphous or microcrystalline polyamide resin below the upper limit, the transparency of the resulting polarizing film protective film tends to be further improved. The polarizing film protective film of this embodiment may contain only one type of amorphous or microcrystalline polyamide resin, or it may contain two or more types. When two or more types are included, it is preferable that the total amount is within the above range.

[0044] <<Resins other than amorphous or microcrystalline polyamide resins, and other components>> The polarizing protective film of this embodiment may or may not contain a polyamide resin other than amorphous or microcrystalline polyamide resin. Furthermore, it may or may not contain an amorphous or microcrystalline thermoplastic resin other than amorphous or microcrystalline polyamide resin.

[0045] Examples of polyamide resins other than amorphous or microcrystalline polyamide resins include aliphatic polyamide resins and aromatic polyamide resins other than amorphous or microcrystalline polyamide resins. Examples of aliphatic polyamide resins other than amorphous or microcrystalline polyamide resins include polyamide 4, polyamide 46, polyamide 6, polyamide 66, polyamide 666, polyamide 610, polyamide 11, polyamide 116, polyamide 12, and polyamide 612. Examples of aromatic polyamide resins include polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), polyamide 66 / 6T, polyamide 9T, polyamide 9MT, polyamide 10T, polyamide 6I / 6T, and xylylenediamine-based polyamide resins (MXD6, etc.).

[0046] For polyamide resins other than amorphous or microcrystalline polyamide resins, it is also preferable to use polyamide resins manufactured using recycled resins or biomass raw materials (biomass polyamide resins). Furthermore, it is preferable that the polarizing film protective film of this embodiment substantially contains no polyamide resins other than amorphous or microcrystalline polyamide resins. Specifically, the content of polyamide resins other than amorphous or microcrystalline polyamide resins in the polarizing film protective film of this embodiment is preferably less than 10% by mass, more preferably less than 5% by mass, even more preferably less than 3% by mass, even more preferably less than 1% by mass, and still more preferably less than 0.1% by mass, based on 100% by mass of the polarizing film protective film.

[0047] Furthermore, the haze of the polarizing protective film of this embodiment, as measured according to JIS K 7136, is preferably less than 1.0%, may be less than 0.50%, or may be 0%.

[0048] The polarizing protective film of this embodiment may contain amorphous or microcrystalline thermoplastic resins other than amorphous or microcrystalline polyamide resins. Examples of amorphous or microcrystalline thermoplastic resins other than amorphous or microcrystalline polyamide resins include polycarbonate resins and polymethyl methacrylate resins, with polycarbonate resins being preferred. The polycarbonate resin is preferably bisphenol A type polycarbonate. Details of the polycarbonate resin can be found in paragraphs 0022 to 0025 of Japanese Patent Application Publication No. 2024-119119, and this information is included herein.

[0049] For thermoplastic resins other than amorphous or microcrystalline polyamide resins, it is also preferable to use thermoplastic resins manufactured using recycled resins or biomass raw materials (biomass thermoplastic resins). Furthermore, if the polarizing film protective film of this embodiment contains an amorphous or microcrystalline thermoplastic resin other than an amorphous or microcrystalline polyamide resin (preferably a polycarbonate resin), the content thereof is preferably 0.001% by mass or more, preferably 10% by mass or less, more preferably 5.5% by mass or less, even more preferably 4% by mass or less, and may be less than 3% by mass, less than 1% by mass, less than 0.1% by mass, or less than 0.01% by mass, based on 100% by mass of the polarizing film protective film.

[0050] The polarizing film protective film of this embodiment may contain other components in addition to resins other than amorphous or microcrystalline polyamide resins, as long as it does not depart from the spirit of the present invention. Examples of other components include polyetheramide elastomers, mold release agents (fatty acid amides, fatty acid esters, polyalkylene glycols, etc.), ultraviolet absorbers, antioxidants, heat stabilizers, flame retardants, flame retardant additives, colorants, antistatic agents, fluorescent whitening agents, antifogging agents, flow modifiers, plasticizers, dispersants, antibacterial agents, antiblocking agents, impact modifiers, sliding modifiers, hue modifiers, acid trapping agents, and the like. Furthermore, the polarizing film protective film of this embodiment may contain additives described in paragraphs 0047 to 0103 of International Publication No. 2021 / 241471, additives described in paragraphs 0041 to 0056 of Japanese Patent Application Publication No. 2023-61203, and additives (cyclic ether compounds) described in paragraphs 0017 to 0021 of International Publication No. 2024 / 029515, without departing from the spirit of the present invention, and these contents are incorporated herein.

[0051] (Polyetheramide elastomer) Polyetheramide elastomers are elastomers that contain both polyether and polyamide structures. The polyetheramide elastomer used in this embodiment preferably comprises a polyalkylene glycol block and a polyamide block. If the polarizing film protective film of this embodiment contains a polyetheramide elastomer, its content is preferably 1% by mass or more, and preferably 20% by mass or less, based on 100% by mass of the polarizing film protective film. A polyetheramide elastomer is an elastomer containing a polyether structure and a polyamide structure. The polyetheramide elastomer in this embodiment is substantially free of ester structures. Substantially free of ester structures means that it is not a so-called polyester etheramide elastomer, and more specifically, the ester structure content is usually less than 1% by mass of the polyetheramide elastomer, preferably less than 0.5% by mass, more preferably less than 0.1% by mass, and even more preferably less than 0.01% by mass. The polyetheramide elastomer used in this embodiment preferably comprises a polyalkylene glycol block and a polyamide block.

[0052] Polyalkylene glycol blocks are -(alkylene group-O) n2 - is preferred to represent the above -(alkylene group-O) n2 The alkylene group in - is preferably a linear or branched alkylene group having 1 to 10 carbon atoms. The number of carbon atoms constituting the alkylene group is preferably 2 or more, more preferably 3 or more, preferably 8 or less, more preferably 6 or less, even more preferably 5 or less, and even more preferably 4 or less. Specific examples of the above -(alkylene group-O)- include -(CH2O)-, -(CH2CH2O)-, -(CH2CH2CH2O)-, -(CH(CH3)CH2O)-, -(CH2CH2CH2CH2O)-, and -(C(CH3)2CH2O)-, and combinations of two or more of these are also acceptable. The above-(alkylene group-O) n2 In -, n2 is preferably between 1 and 200, and more preferably between 3 and 100. The polyalkylene glycol block preferably contains a polypropylene glycol (PPG) block and / or a polytetramethylene ether glycol (PTMG) block.

[0053] In the polyether amide elastomer used in this embodiment, the proportion of the polyalkylene glycol block is preferably 5 mol% or more, more preferably 10 mol% or more, still more preferably 15 mol% or more, and even more preferably 20 mol% or more, based on 100 mol% of all the constitutional units of the polyether amide elastomer. Depending on the use and the like, it may be 30 mol% or more, 40 mol% or more, 50 mol% or more, 60 mol% or more, or 65 mol% or more. By setting it to be not less than the above lower limit value, the impact strength when added to an amorphous or microcrystalline polyamide resin tends to be further improved. Also, in the polyether amide elastomer used in this embodiment, the proportion of the polyalkylene glycol block is preferably 90 mol% or less, more preferably 85 mol% or less, still more preferably 80 mol% or less, and even more preferably 75 mol% or less, based on 100 mol% of all the constitutional units of the polyether amide elastomer. By setting it to be not more than the above upper limit value, it tends to be more easily compatible with the amorphous or microcrystalline polyamide resin. The polyether amide elastomer may contain only one kind of polyalkylene glycol block or may contain two or more kinds. When containing two or more kinds, it is preferable that the total amount is within the above range.

[0054] The polyamide block is preferably represented by an aliphatic polyamide block, -(NH(CH2) n3 C(=O)) n4It is preferable that the aliphatic polyamide block is represented by -. Here, n3 is preferably 3 or more, more preferably 5 or more, even more preferably 7 or more, even more preferably 9 or more, even more preferably 10 or more, and also preferably 20 or less, more preferably 18 or less, even more preferably 16 or less, even more preferably 14 or less, and even more preferably 12 or less. Furthermore, when n3 is an aliphatic dicarboxylic acid having 7 to 20 carbon atoms that constitutes an amorphous or microcrystalline polyamide resin, n5 is considered to be the number of carbon atoms (for example, sebacic acid has n5=10), it is preferable that the difference (absolute value) between n5 and n3 is small. More specifically, it is preferable that |n5-n3| is 3 or less, and more preferably 2 or less. n4 is preferably between 1 and 300, and more preferably between 5 and 100.

[0055] In this embodiment, the proportion of polyamide blocks in the polyetheramide elastomer is preferably 10 mol% or more, more preferably 15 mol% or more, even more preferably 20 mol% or more, and even more preferably 25 mol% or more, based on 100 mol% of the total constituent units of the polyetheramide elastomer. Setting it above the lower limit tends to further improve compatibility with amorphous or microcrystalline polyamide resins. Furthermore, in this embodiment, the proportion of polyamide blocks in the polyetheramide elastomer is preferably 95 mol% or less, more preferably 90 mol% or less, even more preferably 85 mol% or less, and even more preferably 80 mol% or less, based on 100 mol% of the total constituent units of the polyetheramide elastomer. Setting it below the upper limit tends to further suppress the decrease in glass transition temperature when added to amorphous or microcrystalline polyamide resins. The polyetheramide elastomer may contain only one type of polyamide block, or it may contain two or more types. When it contains two or more types, it is preferable that the total amount is within the above range.

[0056] In this embodiment, the polyetheramide elastomer preferably has a total of 90% by mass or more of the polyalkylene glycol block and the polyamide block, more preferably 95% by mass or more, even more preferably 97% by mass or more, and preferably 100% by mass or less of the polyetheramide elastomer.

[0057] The weight-average molecular weight of the polyetheramide elastomer used in this embodiment is preferably 3000 or more, more preferably 5000 or more, preferably 100000 or less, and more preferably 80000 or less. Setting it above the lower limit tends to further improve toughness when mixed with amorphous or microcrystalline polyamide resins. Setting it below the upper limit tends to further improve compatibility with amorphous or microcrystalline polyamide resins. The weight-average molecular weight is an acrylic equivalent value measured by GPC (gel permeation chromatography).

[0058] The polyetheramide elastomer content in the polarizing film protective film of this embodiment is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, even more preferably 5% by mass or more, and even more preferably 7% by mass or more, based on 100% by mass of the polarizing film protective film. Setting the content above the lower limit tends to further improve the impact strength and hue improvement effects when added to amorphous or microcrystalline polyamide resins. Furthermore, the polyetheramide elastomer content in the polarizing film protective film of this embodiment is preferably 20% by mass or less, more preferably 18% by mass or less, even more preferably 16% by mass or less, even more preferably 14% by mass or less, and even more preferably 12% by mass or less, based on 100% by mass of the polarizing film protective film. Setting the content below the upper limit tends to further improve compatibility with amorphous or microcrystalline polyamide resins. The polarizing film protective film of this embodiment may contain only one type of polyetheramide elastomer, or it may contain two or more types. When it contains two or more types, it is preferable that the total amount is within the above range.

[0059] (Release agent) The release agent that may be included in the polarizing protective film of this embodiment is not particularly limited as long as it improves the peelability from metal, and for example, a compound with low reactivity with metal can be used. Specifically, it is preferable to include at least one selected from the group consisting of fatty acid esters, fatty acid amides, and polyalkylene glycols. By using such compounds, the peelability between the roll surface and the die interior and the film raw material is improved, effectively suppressing contamination of the first roll and the formation of a sharkskin-like texture on the film surface during film production, and furthermore, effectively suppressing the generation of die residue in the die slip area.

[0060] Fatty acid esters are typically composed of fatty acids and alcohols. Fatty acid amides, for example, are composed of fatty acids and ammonia and / or amines, or are obtained by ammonia decomposition of fatty acid esters. Polyalkylene glycols are produced, for example, by ring-opening polymerization of alkylene oxides such as propylene oxide. It goes without saying that in this embodiment, at least one selected from the group consisting of fatty acid esters, fatty acid amides, and polyalkylene glycols is used, but is not limited to these.

[0061] In this embodiment, the number of carbon atoms in the fatty acids constituting these fatty acid esters or fatty acid amides is preferably 7 or more, more preferably 8 or more, even more preferably 9 or more, even more preferably 10 or more, even more preferably 11 or more, and also preferably 30 or less, more preferably 28 or less, even more preferably 26 or less, even more preferably 24 or less, even more preferably 22 or less, and even more preferably 20 or less. Setting it above the lower limit makes it easier for the release agent to bleed out onto the surface of the molded body such as the film during molding, and tends to further suppress contamination of the first roll and the film surface from becoming sharkskin-like. Furthermore, setting it below the upper limit tends to improve compatibility with amorphous or microcrystalline polyamide resins, and tends to effectively suppress the release agent itself from becoming contamination of the first roll. The fatty acid may be a straight-chain fatty acid, a branched fatty acid, or a fatty acid having an alicyclic structure, but it is preferably a straight-chain fatty acid and / or a branched fatty acid. Furthermore, the fatty acid may be a saturated fatty acid or an unsaturated fatty acid. Also, the fatty acid may be a hydroxycarboxylic acid. Furthermore, the number of carboxyl groups (-COOH) contained in one fatty acid molecule is preferably 1 to 10, and more preferably 1 to 4.

[0062] Here, we will explain the details of fatty acid esters. The number of ester bonds (-C(=O)O-) in one molecule of fatty acid ester is preferably 1 to 10, and more preferably 1 to 4. The fatty acid ester used in this embodiment is preferably a full ester (a fatty acid ester that does not contain unesterified COOH). Furthermore, the alcohol constituting the fatty acid ester is preferably an aliphatic alcohol. The aliphatic alcohol may be a linear aliphatic alcohol, a branched aliphatic alcohol, or an aliphatic alcohol having an alicyclic structure, but it is preferably a linear aliphatic alcohol and / or a branched aliphatic alcohol. Also, the aliphatic alcohol may be a saturated aliphatic alcohol or an unsaturated aliphatic alcohol, but it is preferably a saturated aliphatic alcohol. Furthermore, the aliphatic alcohol is preferably a 1-10 hydride alcohol, and more preferably a 1-4 hydride alcohol. The aliphatic alcohol preferably has 1 or more carbon atoms, more preferably 2 or more, even more preferably 3 or more, preferably 30 or less, more preferably 25 or less, even more preferably 20 or less, even more preferably 15 or less, and even more preferably 10 or less.

[0063] In this embodiment, the aliphatic ester is preferably at least one of monoesters, diesters, triesters, and tetraesters composed of a fatty acid having 7 to 30 carbon atoms and a 1 to 4-valent alcohol. Furthermore, the fatty acid ester is preferably a full ester. The molecular weight of the fatty acid ester is preferably 100 or more, and preferably 2000 or less.

[0064] In this embodiment, when fatty acid esters are used, specific examples include methyl laurate, methyl stearate, methyl oleate, butyl stearate, isopropyl myristate, isopropyl palmitate, 2-ethylhexyl palmitate, 2-ethylhexyl stearate, 2-ethylhexyl oleate, cetyl myristate, myristyl myristate, stearyl stearate, behenyl behenate, and montanic acid wax.

[0065] Next, we will explain the details of fatty acid amides. The number of amide bonds (-C(=O)NH-) in one molecule of fatty acid amide is preferably 1 to 10, and more preferably 1 to 4. Furthermore, it is preferable that the fatty acid amide is composed of a fatty acid and an amine. The amine constituting the fatty acid amide is preferably an aliphatic amine. The aliphatic amine may be a linear aliphatic amine, a branched aliphatic amine, or an aliphatic amine having an alicyclic structure, but it is preferable that it be a linear aliphatic amine and / or a branched aliphatic amine. Furthermore, the aliphatic amine may be a saturated aliphatic amine or an unsaturated aliphatic amine, but it is preferable that it be a saturated aliphatic amine. Furthermore, the aliphatic amine preferably has 1 to 10 amino groups per molecule, and more preferably has 1 to 4 amino groups.

[0066] In this embodiment, the aliphatic amide is preferably at least one of monoamides, diamides, triamides, and tetraamides, which are composed of a fatty acid having 7 to 30 carbon atoms and an amine having 1 to 4 amino groups in one molecule. Furthermore, the aliphatic amide is preferably a fatty acid amide that does not have an amino group (-NH2). The molecular weight of the fatty acid amide is preferably 100 or more, and preferably 1000 or less.

[0067] In this embodiment, when using fatty acid amides, specific examples include stearic acid amide, oleic acid amide, erucic acid amide, behenic acid amide, palmitic acid amide, ethylenebisoleic acid amide, and ethylenebiserucic acid amide.

[0068] Next, we will describe the details of polyalkylene glycol. The polyalkylene glycol preferably contains ethylene glycol units and / or propylene glycol units in a total proportion of 50 mol% or more of the total units, and has a number-average molecular weight of 100 to 3500.

[0069] In this embodiment, the polyalkylene glycol preferably consists of ethylene glycol units and / or propylene glycol units totaling 50 mol% or more of the total units, more preferably 60 mol% or more, even more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and especially most preferably 99 mol% or more. Furthermore, all units other than the terminal groups may consist of ethylene glycol units and / or propylene glycol units. By setting the value above the lower limit, the accumulation of the resin composition due to improved slipperiness with the inner wall of the molding machine, caused by polyalkylene glycol bleeding out onto the surface of the molded article such as a film during molding, tends to further suppress soiling of the first roll and the formation of a sharkskin-like texture on the film surface. Furthermore, by ensuring that the total amount of ethylene glycol units and / or propylene glycol units is 50 mol% or more of the total units, the material becomes more appropriately compatible with amorphous or microcrystalline polyamide resins. This effectively suppresses excessive bleed-out of polyalkylene glycol onto the surface of molded articles such as films during molding, and tends to effectively suppress contamination of the first roll caused by the polyalkylene glycol itself.

[0070] In this embodiment, the polyalkylene glycol may contain other monomer units in addition to ethylene glycol units and propylene glycol units. The other monomer units are preferably alkylene glycol units other than ethylene glycol units and propylene glycol units. Other examples of alkylene glycol units include methylene glycol, butylene glycol, pentylene glycol, hexylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, neopentyl glycol, 3-methyltetramethylene glycol, and hexamethylene glycol.

[0071] In this embodiment, the polyalkylene glycol may be modified at its terminal ends with any substituent. Furthermore, the modification of the ends may be limited to one end of the polyalkylene glycol or it may be limited to both ends. Examples of optional substituents include carboxyl groups, hydroxyl groups, alkyl ethers, aryl ethers, aralkyl ethers, fatty acid esters, and aryl esters.

[0072] In this embodiment, the number-average molecular weight of the polyalkylene glycol is preferably 100 to 3500, more preferably 300 or more, even more preferably 500 or more, even more preferably 800 or more, and even more preferably 1000 or more. The upper limit is more preferably 3000 or less, even more preferably 2000 or less, and even more preferably 1500 or less. Setting it above the lower limit tends to effectively suppress the volatilization of the polyalkylene glycol. Setting it below the upper limit tends to more effectively suppress the decrease in transparency. This is presumed to be because polyalkylene glycol does not easily become completely miscible with amorphous or microcrystalline polyamide resin, forming a sea-island structure. When the number-average molecular weight of the polyalkylene glycol is large, the island portion expands, the refractive index difference increases, and transparency decreases. The number-average molecular weight is measured according to JIS K1577.

[0073] In this embodiment, when polyalkylene glycol is used, specific examples include polyethylene glycol, polypropylene glycol, or copolymers containing ethylene glycol units and / or propylene glycol units with other alkylene glycol units. Polyethylene glycol or propylene glycol is preferred, and polypropylene glycol is more preferred from the viewpoint of ease of manufacture.

[0074] In this embodiment, the polyalkylene glycol is not particularly limited and may be produced by known methods or a commercially available product may be used. Examples of commercially available products include D-1000 (manufactured by NOF Corporation), D-2000 (manufactured by NOF Corporation), D-4000 (manufactured by NOF Corporation), and the like.

[0075] The release agent content in the polarizing film protective film of this embodiment is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, even more preferably 0.01% by mass or more, even more preferably 0.1% by mass or more, even more preferably 0.3% by mass or more, and also preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, even more preferably 2% by mass or less, and even more preferably 1% by mass or less. Setting the release agent above the lower limit tends to effectively suppress contamination of the first roll during molding and the formation of a sharkskin-like texture on the film surface. Furthermore, setting the release agent below the upper limit tends to more effectively suppress a decrease in transparency, glass transition temperature, and toughness. The polarizing protective film of this embodiment may contain only one type of release agent, or it may contain two or more types. When it contains two or more types, it is preferable that the total amount is within the above range.

[0076] If the polarizing protective film of this embodiment contains the above-mentioned other components, the total content is preferably 0.001 to 3% by mass of the polarizing protective film, more preferably less than 2% by mass, even more preferably less than 1% by mass, even more preferably less than 0.5% by mass, even more preferably less than 0.1% by mass, and may be less than 0.01% by mass. The polarizing protective film may contain only one other component or two or more other components. When it contains two or more other components, it is preferable that the total amount is within the above range.

[0077] The shape of the polarizing film protective film in this embodiment is not particularly defined, but it is preferable that the length of the long side is 300 mm or more, and the length of the short side of the polarizing film protective film is 290 mm or more. The upper limit of the length of the long side is not particularly defined, but for example, it is 100,000 mm or less. The upper limit of the length of the short side is, for example, 500 mm or less, and may be 400 mm or less, 350 mm or less, or 310 mm or less. In the case where the polarizing film protective film of this embodiment is a uniaxially oriented film, it is preferable that the direction of the stretch axis is in the direction of the long side of the film. The polarizing protective film of this embodiment may be a winding body wound around a core material.

[0078] <Method for manufacturing polarizing protective film> The method for manufacturing a polarizing protective film of this embodiment is a polarizing protective film comprising an amorphous or microcrystalline polyamide resin, wherein the retardation (Re) of the polarizing protective film is 3000 nm or more and 5000 nm or less, and when the center line between the two sides of the film, which is nearly parallel to the slow-moving axis determined when the retardation (Re) of the polarizing protective film is measured, is defined as direction E1, the deviation from direction E1 of the slow-moving axis at the center of the polarizing protective film and the slow-moving axis at a position 20 mm toward the center line from both sides of the polarizing protective film is both less than ±2.0°, or the polarizing protective film A method for manufacturing a polarizing film protective film, wherein when the side of the film that is closest to being parallel to the slow-moving axis determined when the retardation (Re) of the protective film is measured is defined as the stretching direction E2, the deviation from the stretching direction E2 of the slow-moving axis at the center of the polarizing film protective film and the slow-moving axis at positions 20 mm from both ends of the polarizing film protective film is both less than ±2.0°, and the thickness (T1) of the polarizing film protective film is 150 μm or more and 270 μm or less, the method comprising uniaxial stretching of a polyamide resin film containing an amorphous or microcrystalline polyamide resin, wherein the magnification during stretching is greater than 0 and 1.9 times or less. By performing uniaxial stretching in this manner and reducing the stretching ratio, a polarizing protective film can be obtained that provides a polarizing sheet in which the curves in the X direction and Y direction of the sheet surface are easily aligned during heat bending while maintaining high retardation. Furthermore, it is also possible to obtain a polarizing protective film that effectively suppresses light leakage when used as a polarizing sheet.

[0079] The resin film containing amorphous or microcrystalline polyamide resin of this embodiment preferably has a width (in the direction perpendicular to the stretching direction, the short side) of 300 mm or more before stretching, more preferably 350 mm or more, and may also be 400 mm or more, or 650 mm or less, 600 mm or less, 550 mm or less, or 500 mm or less.

[0080] The temperature of the stretching booth during stretching is preferably in the range of Tmg-15°C to Tmg+17°C, based on the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin. The surface temperature of the stretching roll immediately before stretching is preferably in the range of Tmg-15°C to Tmg-5°C, based on the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin. In particular, it is more preferable that the stretching booth temperature during stretching is in the range of Tmg-15°C to Tmg+17°C, based on the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin, and that the surface temperature of the stretching roll immediately before stretching is in the range of Tmg-15°C to Tmg-5°C, based on the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin.

[0081] The polarizing film protective film is the same as the polarizing film protective film of the embodiment described above, and the preferred range is also the same.

[0082] The method for manufacturing the polarizing film protective film of this embodiment will be described below with reference to Figure 1. It goes without saying that the method for manufacturing the polarizing film protective film of this embodiment is not limited to Figure 1. As shown in Figure 1, in the manufacture of the polarizing film protective film of this embodiment, a resin film (raw material, reference numeral 10) containing an amorphous or microcrystalline polyamide resin is stretched. Here, the resin film containing amorphous or microcrystalline polyamide resin, which is the raw material 10, has a composition that is typically the same as the composition of the stretched film (i.e., the polarizing film protective film in this embodiment).

[0083] The resin film 10 containing amorphous or microcrystalline polyamide resin is usually wound onto a core material or the like, and the resin film is sequentially unwound during the manufacture of the polarizing film protective film. The unwound speed is preferably 1 m / min or more, more preferably 2 m / min or more, preferably 10 m / min or less, more preferably 5 m / min or less, and may be 4 m / min or less.

[0084] The unwound resin film 10 goes through a heating zone 11, a stretching zone 12, and a cooling zone 13, and is then wound onto another core material. Reference numeral 14 in Figure 1 indicates a winding body in which the polarizing protective film is wound onto the core material. In the heating zone 11, as shown in Figure 1, heating occurs via three rolls: No. 1 roll (1R), No. 2 roll (2R), and No. 3 roll (3R). In this embodiment, it is preferable that the surface temperature of the stretching roll (No. 3 roll) immediately before stretching is in the range of Tmg-15°C to Tmg-5°C, based on the glass transition temperature Tmg of the amorphous or microcrystalline polyamide resin. Setting the surface temperature of the stretching roll (3R) immediately before stretching to above the lower limit tends to reduce the likelihood of film breakage during stretching. Furthermore, setting the surface temperature to below the upper limit tends to reduce adhesion to the roll during stretching. It is more preferable that the surface temperature of the stretching roll (3R) immediately before stretching be Tmg-14°C or higher, more preferably Tmg-6°C or lower, and even more preferably Tmg-7°C or lower. Such a surface temperature is beneficial in that it is possible to achieve high transparency while keeping the retardation value low. The surface roll temperatures of No. 1 roll (1R) and No. 2 roll (2R) can be determined as appropriate. The surface temperature of the 1R roll is preferably Tmg - 25°C or higher, based on the glass transition temperature Tmg of the amorphous or microcrystalline polyamide resin, and is less than or equal to the surface temperature of the stretching roll (3R) immediately before stretching. Furthermore, the surface temperature of the 2R roll is preferably higher than the surface temperature of the 1R roll.

[0085] In the embodiment shown in Figure 1, the material is heated in the heating zone 11 and then stretched in the stretching zone 12. More specifically, in the embodiment shown in Figure 1, stretching is performed by the difference in peripheral speed between the stretching roll (3R) located immediately before the stretching zone 12 and the No. 4 roll (4R) located immediately after the stretching zone 12. The stretching ratio at this time is greater than 0 and less than or equal to 1.9, preferably 0.5 or more, more preferably 1.0 or more, even more preferably 1.5 or more, 1.6 or more, and may even be 1.7 or more, and preferably less than 1.9, and more preferably 1.8 or less. Setting the stretching ratio above the lower limit tends to increase retardation (Re). Setting the stretching ratio below the upper limit tends to make the curves in the X direction and Y direction of the sheet surface more aligned during heat bending. Here, in the case of batch stretching, even if the stretching ratio is adjusted, it is difficult to perform uniform stretching throughout the entire film, making it difficult to suppress the shift of the slow axis throughout the entire film. This is because when stretching in a batch manner with only the four sides of the film held by clamps, neck-in tends to occur strongly in the unheld parts, causing a large shift of the slow axis in those parts.

[0086] In the embodiment shown in Figure 1, the temperature of the stretching booth 15 during stretching is preferably in the range of Tmg-15°C to Tmg+17°C, based on the glass transition temperature Tmg of the amorphous or microcrystalline polyamide resin of this embodiment described above. Setting the temperature of the stretching booth 15 during stretching to above the lower limit tends to reduce the likelihood of film breakage during stretching. Furthermore, setting the temperature of the stretching booth 15 to below the upper limit tends to increase the retardation (Re). The temperature of the stretching booth 15 is more preferably Tmg-14°C or higher, even more preferably Tmg-12°C or higher, and may also be Tmg-10°C or higher, and is preferably Tmg+15°C or lower, more preferably Tmg+12°C or lower, and may also be Tmg+10°C or lower.

[0087] In the cooling zone 13, which follows the stretching zone 12, the material is cooled via three rolls: No. 4 roll (4R), No. 5 roll (5R), and No. 6 roll (6R), in the configuration shown in Figure 1. The surface temperature of 4R is preferably 10°C or more below the surface temperature of 3R, and below the surface temperature of 3R. Furthermore, the surface roll temperatures of the No. 5 roll (5R) and No. 6 roll (6R) can be determined as appropriate. Generally, the surface temperature of the 5R is preferably lower than or equal to the surface temperature of the 4R, and the surface temperature of the 6R is preferably lower than or equal to the surface temperature of the 5R. The stretched resin film 10 (polarizing film protective film) having obtained the cooling zone 13 is wound onto a core material to form a winding body 14.

[0088] <Polarizing sheet> The polarizing sheet of this embodiment includes the polarizing film protective film of this embodiment. More specifically, the polarizing sheet of this embodiment is a polarizing sheet having a first polarizing film protective film, a polarizing film, and a second polarizing film protective film in the order described above, wherein the first polarizing film protective film is the polarizing film protective film of this embodiment.

[0089] The first polarizing film protective film and the second polarizing film protective film serve as the polarizing film substrates of the polarizing sheet, and are usually bonded to the polarizing film via an adhesive. That is, an example of a polarizing sheet in this embodiment includes a multilayer in which the first polarizing film protective film, adhesive layer, polarizing film, adhesive layer, and second polarizing film protective film are in contact with each other in the order described above. A known polarizing film can be used, and an example is one in which iodine or a dichroic organic dye is adsorbed or impregnated onto a polyvinyl alcohol (PVA) film.

[0090] The adhesive used to bond the polarizing film protective film and the polarizing film can be a known adhesive, such as an acrylic adhesive, a urethane adhesive, an epoxy adhesive, a silicone adhesive, or a polyvinyl alcohol adhesive. Among these, a urethane adhesive is preferred. The thickness of the adhesive is typically 1 μm or more, and typically 30 μm or less.

[0091] The first polarizing film protection film can use the polarizing film protection film of the above-described embodiment, and the preferable range is also the same. For the second polarizing film protection film, the same one as the first polarizing film protection film can be used, but those having the following characteristics are preferably used.

[0092] The second polarizing film protection film preferably has a thickness thinner than that of the first polarizing film protection film. Specifically, the ratio (T1 / T2) of the thickness (T1) of the first polarizing film protection film to the thickness (T2) of the second polarizing film protection film preferably satisfies 1.0 < T1 / T2 < 1.67. By adopting such a configuration, a polarizing sheet with more excellent thermoforming properties can be obtained. The ratio (T1 / T2) is more preferably 1.60 or less, further preferably 1.50 or less, still more preferably 1.40 or less, and may also be 1.30 or less. Moreover, it is more preferably 1.10 or more, and may further be 1.15 or more or 1.20 or more.

[0093] The second polarizing film protection film preferably has a retardation (Re) of 2 nm or more and 500 nm or less. The retardation (Re) is preferably 100 nm or less, more preferably 50 nm or less, and may also be 5 nm or more.

[0094] The second polarizing film protection film may be stretched or may not be stretched. In the present embodiment, the second polarizing film protection film is preferably not stretched.

[0095] The thickness (T2) of the second polarizing protective film is preferably 100 μm or more, may be 120 μm or more, preferably 240 μm or less, and more preferably 220 μm or less. Setting the thickness (T2) of the second polarizing protective film to be above the lower limit tends to reduce the likelihood of wrinkles occurring during lamination with the PVA film. Furthermore, setting the thickness (T2) of the second polarizing protective film to be below the upper limit tends to improve the alignment of the X-direction curve and the Y-direction curve of the sheet surface during heat bending.

[0096] The retardation (Re) and thickness of the second polarizing protective film are measured according to the examples described below.

[0097] The second polarizing film protective film preferably contains an amorphous or microcrystalline polyamide resin. The amorphous or microcrystalline polyamide resin may be selected with reference to the matters described in the section on the polarizing film protective film of this embodiment above, and the preferred range is the same. The content of amorphous or microcrystalline polyamide resin in the second polarizing film protective film is preferably 90% by mass or more, more preferably 94.5% by mass or more, even more preferably 96% by mass or more, and preferably 99.999% by mass or less, based on 100% by mass of the second polarizing film protective film.

[0098] The second polarizing protective film may contain other components in addition to amorphous or microcrystalline polyamide resin, as long as it does not depart from the spirit of the present invention. Examples of other components include polyetheramide elastomer, mold release agent, ultraviolet absorber, antioxidant, heat stabilizer, flame retardant, flame retardant aid, colorant, antistatic agent, fluorescent whitening agent, antifogging agent, flow improver, plasticizer, dispersant, antibacterial agent, antiblocking agent, impact improver, sliding improver, hue improver, acid trapper, etc. Furthermore, the second polarizing protective film may contain additives described in paragraphs 0047-0103 of International Publication No. 2021 / 241471 and additives described in paragraphs 0041-0056 of Japanese Patent Application Publication No. 2023-61203, without departing from the spirit of the present invention, and these contents are incorporated herein. If the second polarizing protective film contains components other than amorphous or microcrystalline polyamide resin, the content of these components is preferably 0.001 to 3% by mass of the second polarizing protective film.

[0099] In addition to the above, the second polarizing film protective film of the polarizing sheet of this embodiment can be any known polarizing film protective film, without departing from the spirit of the present invention. As the second polarizing film protective film, the polyamide resin films (1) and (2) described in Japanese Patent Application Publication No. 2022-78090, the polyamide resin forming layer described in Japanese Patent No. 4987297, the polyamide resin films (1) and (2) described in Japanese Patent No. 7350464, etc., are used, and the details of these are incorporated herein.

[0100] Furthermore, the haze of the second polarizing protective film, as measured according to JIS K 7136, is preferably less than 1.0%, may be less than 0.5%, or may be 0%.

[0101] The polarizing sheet of this embodiment can be made thinner. The total thickness of the polarizing sheet in this embodiment is preferably 535 μm or less, more preferably 530 μm or less, even more preferably 500 μm or less, even more preferably 495 μm or less, and also preferably 270 μm or more, more preferably 300 μm or more, and may be 350 μm or more or 400 μm or more depending on the application. By setting the total thickness of the polarizing sheet to the upper limit or less, the processing time during heat bending tends to be shortened. Also, by setting the total thickness of the polarizing sheet to the lower limit or more, the handling during heat bending tends to be improved. Furthermore, if the polarizing sheet of this embodiment has a multilayer body comprising a first polarizing film protective film, an adhesive, a polarizing film, an adhesive, and a second polarizing film protective film, the total thickness of the multilayer body is preferably 535 μm or less, more preferably 530 μm or less, even more preferably 500 μm or less, even more preferably 495 μm or less, and also preferably 270 μm or more, more preferably 300 μm or more, and may be 350 μm or more or 400 μm or more depending on the application.

[0102] The polarizing sheet of this embodiment may have other layers besides those described above. Examples of other layers include a hard coat layer and an infrared absorption layer. Details of the hard coat layer will be described later.

[0103] The method for manufacturing the polarizing sheet is not particularly limited; for example, conventionally known methods can be used.

[0104] <Heat-bent molded product> The heat-bent molded body of this embodiment is obtained by heat-bending the polarizing sheet of this embodiment. Figure 2 is a schematic diagram showing an example of using the polarizing sheet (multilayer for heat bending) of this embodiment in the manufacture of a heat-bent molded product, where 1 is the second polarizing film protective film, 6 is the polarizing film, 7 is the polarizing film protective film of this embodiment (first polarizing film protective film), and 8 is the mold. In Figure 2, each component (1, 6, 7) is shown separately, but normally these components are bonded together with an adhesive to form a polarizing sheet, which is then placed in the mold 8. In this embodiment, it is preferable that the first polarizing film protective film side is a curved convex surface (the side indicated by the arrow in Figure 2), and the second polarizing film side is a curved concave surface.

[0105] Furthermore, in this embodiment, the heat-bent molded body is obtained by placing the polarizing sheet of this embodiment in contact with the mold (for example, a metal female mold) 8, reducing the pressure to make it adhere tightly to the mold 8, and obtaining a stamped piece that has been adsorbed. It is preferable to adsorb the polarizing sheet to the mold 8 and remove it from the mold 8 while adsorbing it using a male mold. Although the male mold used for adsorption to and removal from the mold is sometimes also referred to as a mold, the mold in this embodiment is a mold having a mold for the desired heat-bent shape.

[0106] In this embodiment, it is preferable to heat-bend the polarizing sheet of this embodiment at a temperature of Tmg-12°C to Tmg-6°C, based on the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin contained in the first polarizing film protective film. Setting the heat-bending temperature above the lower limit tends to make it easier for the curves in the X direction and Y direction of the sheet surface during heat bending to align. Conversely, setting the heat-bending temperature below the upper limit tends to make it more difficult for the shape of the mold surface to be transferred. The heat bending temperature is more preferably Tmg-11°C or higher, even more preferably Tmg-10°C or higher, and even more preferably Tmg-7°C or lower.

[0107] In this embodiment, the heat-bent molded article preferably has a difference (absolute value) of ±3 or less between the curve value in the X direction and the curve value in the Y direction of the polarizing sheet surface, more preferably ±2 or less, and even more preferably ±1 or less. The lower limit of the difference in the curve values ​​is 0 or more. The curve value is calculated as (refractive index of the material - refractive index of air) / radius of curvature (m).

[0108] <Hard coat layer> The polarizing sheet and heat-bent molded body of this embodiment may have a hard coat layer on their surface. In particular, when the polarizing sheet and heat-bent molded body of this embodiment are used in sunglasses, it is preferable to have a hard coat layer on the surface on the side where the lens is not provided. The hard coat layer is preferably obtained by applying a hard coat material that can be cured by heat or by active energy rays, and then curing it. Examples of materials (paints) cured using active energy rays include polarizing film protective films composed of one or more monofunctional or polyfunctional (preferably 2 to 10-functional) (meth)acrylate monomers or oligomers, and preferably polarizing film protective films containing monofunctional or polyfunctional (preferably 2 to 10-functional) urethane (meth)acrylate oligomers. These polarizing film protective films preferably contain a photopolymerization initiator as a curing catalyst. Examples of thermosetting materials (paints) include polyorganosiloxane-based and cross-linked acrylic-based materials. Such polarizing protective films are also commercially available as acrylic resin or polycarbonate resin films or hard coat agents for sheets, and should be selected appropriately considering their suitability with the painting line. For the hard coat layer, reference can be given to paragraphs 0045 to 0055 of Japanese Patent Publication No. 2013-020130, paragraphs 0073 to 0076 of Japanese Patent Publication No. 2018-103518, and paragraphs 0062 to 0082 of Japanese Patent Publication No. 2017-213771, and these contents are incorporated herein by reference.

[0109] In addition to the above components, the hard coat layer may also contain light stabilizers, heat stabilizers, flame retardants, flame retardant additives, antistatic agents, fluorescent whitening agents, anti-fogging agents, flow modifiers, plasticizers, dispersants, antibacterial agents, antiblocking agents, impact modifiers, sliding modifiers, color modifiers, acid trapping agents, etc. One of these components may be used, or two or more may be used in combination.

[0110] The thickness of the hard coat layer is typically 1 to 10 μm.

[0111] <Application> The polarizing sheet or heat-bent molded article of this embodiment is preferably used as a polarizing sheet for liquid crystal display devices, a polarizing lens (sunglasses, ski goggles, prescription eyeglass lenses, camera viewfinder lenses), covers for various instruments, automobile glass, train glass, polarizing sheets for in-vehicle display panels and electronic equipment housings, in-vehicle rearview mirrors, and silver mirrors for helmets. The polarizing sheet or heat-bent molded article of this embodiment is particularly preferably used in sunglasses. [Examples]

[0112] The present invention will be described in more detail below with reference to examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate, as long as they do not depart from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or other reasons, measurements can be taken using other instruments with equivalent performance.

[0113] 1. Raw materials XE3805, manufactured by EMS, is a polyamide resin synthesized from bis(4-amino-3-methylcyclohexyl)methane and dodecanedioic acid. It is an amorphous polyamide resin with a glass transition temperature of 149.5°.

[0114] 2. Measurement of glass transition temperature The intermediate glass transition temperature (Tmg) of the polyamide resin was measured according to the following method. Specifically, in accordance with JIS K7121, 10 mg of the raw material was sampled and the intermediate glass transition temperature (Tmg) was measured. Specifically, a differential scanning calorimetry (DSC-60A, manufactured by Shimadzu Corporation) was used to measure the DSC curve under the following conditions: the sample was first heated to 230°C, cooled to room temperature (below 30°C) at a rate of 20°C / min, and then heated again from room temperature to 230°C at a rate of 10°C / min. The intermediate glass transition temperature obtained from the resulting DSC curve was defined as the intermediate glass transition temperature (Tmg).

[0115] 3. Example 1 (Manufacturing of unoriented film) <Manufacturing of film raw materials> The above amorphous or microcrystalline polyamide resin (XE3805) was extruded into a molten state using a T-die melt extruder consisting of a vented single-screw extruder (manufactured by Shibaura Machine Co., Ltd.) with a screw nominal diameter of 50 mm and a screw L / D = 32, at a discharge rate of 50 kg / h and a screw rotation speed of 100 rpm. After being compressed between the first and second rolls, the film was cooled and solidified to produce a film. The 10 mm ends of the produced film were cut off with a slitter knife set parallel to the molding direction before winding. The cylinder temperature and die temperature were 280°C, and the surface temperature of the first and second rolls was 120°C. The film was then wound onto a core material to obtain a raw film roll. The thickness of the obtained film was 200 μm. Details of the first and second rolls used are as follows. • First roll: Manufactured by Shibaura Machine Co., Ltd., UM roll Dimensions: Outer diameter 250mm x Roll width 600mm • Second roll: Manufactured by Shibaura Machine Co., Ltd., rigid metal roll (surface: chrome plated) Dimensions: Outer diameter 250 mm x Roll width 600 mm. The thickness of the obtained unstretched film is shown in Table 1.

[0116] 4. Examples A1-A9, Comparative Examples A1-A4 (Manufacturing of polarizing protective films) <Manufacturing of film raw materials> The above amorphous or microcrystalline polyamide resin (XE3805) was extruded into a molten state using a T-die melt extruder consisting of a vented single-screw extruder (manufactured by Shibaura Machine Co., Ltd.) with a screw nominal diameter of 50 mm and a screw L / D = 32, at a discharge rate of 50 kg / h and a screw rotation speed of 100 rpm. After being compressed between the first and second rolls, the film was cooled and solidified to produce a film. The 10 mm ends of the produced film were cut off with a slitter knife set parallel to the molding direction before winding. The cylinder temperature and die temperature were 280°C, and the first and second roll temperatures were 120°C. The film was then wound onto a core material to obtain a raw film roll. The thickness of the obtained film was 300 μm. Details of the first and second rolls used are as follows. • First roll: Manufactured by Shibaura Machine Co., Ltd., UM roll Dimensions: Outer diameter 250mm x Roll width 600mm • Second roll: Manufactured by Shibaura Machine Co., Ltd., rigid metal roll (surface: chrome plated) Dimensions: Outer diameter 250mm x Roll width 600mm

[0117] <Stretching of film rolls> The film roll was stretched according to the procedure shown in Figure 1. Specifically, the film roll 10 obtained above was unwound from the core material at the unwinding speed shown in Table 1, and the resin film 10 was heated while passing through the No. 1 roll (1R), No. 2 roll (2R), and No. 3 roll (3R). The surface temperature of the No. 1 roll was 130°C, the surface temperature of the No. 2 roll was 135°C, and the surface temperature of the No. 3 roll was the temperature shown in Table 1 (No. 3R temperature). After heating with the aforementioned rolls No. 1 to No. 3, the material was stretched in stretching zone 12. The temperature and stretching ratio (in units of times) of the stretching booth 15 in stretching zone 12 were as shown in Table 1 (booth temperature, stretching ratio). After stretching, the resin film 10 was cooled while passing through rolls No. 4 (4R), No. 5 (5R), and No. 6 (6R) to obtain a stretched film (polarizing protective film). The surface temperature of rolls No. 4 and No. 5 was 135°C, and the surface temperature of roll No. 6 was 110°C. The stretch ratio was adjusted to the values ​​shown in Table 1, based on the difference in peripheral speed between roll No. 4 and roll No. 3. The 10mm ends of the stretched film were cut off before winding using a slitter knife set parallel to the stretching direction.

[0118] [Table 1]

[0119] All of the films obtained above had a haze level of less than 1.0% as measured according to JIS K 7136.

[0120] <Measurement of the thickness of polarizing protective film and polarizing sheet> The thickness of the polarizing protective film and polarizing sheet was measured using the following method. The thickness value was defined as the average of five measurements taken in the width direction of the obtained polarizing protective film and polarizing sheet. Measurements were taken at a total of five points: two points at the film edges, one point in the center of the film, and two points midway between the edges and the center. The measuring instrument used was a Mitutoyo MDC-25SX Digimatic standard outside micrometer manufactured by Mitutoyo Corporation. The thickness of polarizing protective films and polarizing sheets is expressed in μm (micrometers).

[0121] <Measurement of retardation (Re) of polarizing protective film> The average value of three measurements taken in the width direction of the obtained polarizing protective film was defined as Re. Specifically, a 40mm x 40mm test piece was cut from two points on the film edge and one point in the center of the film, and Re was measured. For the measurement, the test piece was set in a phase difference / elliptic polarization measuring device (KOBRA-HBR, manufactured by Oji Instruments Co., Ltd.), and the phase difference at a wavelength of 589.3nm and an incident angle of 0° was measured at one point in the center of the test piece film to determine Re. The results are shown in Table 2. The retardation (Re) of the polarizing protective film is expressed in nm.

[0122] <Deviation from directions E1 and E2 of the slow-moving axis of the polarizing protective film> The shift in the slow axis of the polarizing protective film was measured. The following explanation will be given with reference to Figure 3. The center line between the nearly parallel edges (L and R in Figure 3) of the polarizing protective film was defined as direction E1. 40mm x 40mm measurement samples were cut out from two points at both ends (L1 and R1 in Figure 3) and the central part (C1 in Figure 3) in a plane perpendicular to direction E1. At this time, the center of C1 coincided with E1, and L1 and R1 were positioned 20mm from either edge (L or R) toward E1. The sample for measurement was placed in a phase difference / elliptic polarization measuring device (KOBRA-HBR, manufactured by Oji Instruments Co., Ltd.), and the slow axis was measured under conditions of a wavelength of 589.3 nm and an incident angle of 0°. The angle of the slow axis and the deviation from direction E1 were measured for three measurement samples (L1, C1, R1). Specifically, the arrows in Figure 3 indicate the direction of the slow axis of the L1, C1, and R1 samples (the angles of the arrows are illustrative and not precise), and the angle between E1 and each arrow represents the deviation. When the film was stretched, the film edge that was nearly parallel to the slow-moving axis determined during the measurement of the retardation (Re) of the polarizing protective film was defined as the stretching direction E2, and the deviation of the slow-moving axis from E2 (in degrees) was measured for three measurement samples (L1, C1, R1). In this example, E1 and E2 were almost identical, with a difference of less than 0.1°. The results are shown in Table 2.

[0123] [Table 2]

[0124] As is clear from the results above, the polarizing protective film of the present invention exhibited high retardation despite its thinness. Furthermore, the shift in the slow axis was small.

[0125] 5. Examples B1-B9, Comparative Examples B1-B4 (Manufacturing of polarizing sheets) <Fabrication of polarizing films> A polyvinyl alcohol film (manufactured by Kuraray Co., Ltd.) was swollen in water at 35°C, and then dyed in an aqueous solution at 35°C containing dichroic dyes Kayarus Blue G (C.I. Blue 78), Sumilight Red 4B (C.I. Red 81), Chrysophenine (C.I. Yellow 12) and 10 g / L of anhydrous sodium sulfate, and immersed in an aqueous solution at 35°C containing 2.5 g / L of nickel acetate and 5 g / L of boric acid, and finally stretched to a magnification of 4 times. The film was heat-treated at 110°C for 3 minutes while maintaining a tension state to obtain a 30-μm polarizing film. The obtained polarizing film was stored in a low-humidity storage until the next process.

[0126] <Preparation of Polarizing Sheet> On one side of the first film (the first polarizing film protection film) shown in Table 3, a two-component moisture-curing polyurethane adhesive (main agent: manufactured by Mitsui Chemicals, "Takelac A-520", curing agent: manufactured by Mitsui Chemicals, "Takenate A-50") was applied, and laminated with the polarizing film obtained above with the stretching axes aligned. For the remaining one side of the polarizing film, the film obtained in Reference Example 1 (the second polarizing film protection film) was used and laminated in the same manner. After lamination, it was left in a constant-temperature bath at 70°C to cure the adhesive, and a polarizing sheet was obtained. The thickness of the adhesive was 10 μm each.

[0127] <Measurement of X Curve and Y Curve> After punching out the obtained polarizing sheet to a diameter of 8 cm, it was placed in a concave-shaped mold, and while performing vacuum suction from the suction holes provided in the lower part of the concave-shaped mold, a convex-shaped mold was pressed against it for 2 minutes to perform thermoforming. The concave-shaped mold and the convex-shaped mold were controlled at 140°C and 142°C respectively for processing. Regarding the obtained polarizing sheet after bending, the curve value in the X direction was defined as the X curve, and the curve value in the Y direction was defined as the Y curve, and the measurement was performed using a RADIUS GAUGE (manufactured by Carton Optics Co., Ltd., product number 591, corresponding to a refractive index of 1.525). The results are shown in Table 3.

[0128]

Table 3

[0129] In Table 3 above, "nd." indicates that there is no data. As is clear from the results above, despite its thinness, the polarizing sheet of the present invention showed a small difference between the curve values ​​in the X direction and the curve values ​​in the Y direction of the sheet surface during heat bending.

[0130] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible without departing from the intent and scope of the invention. [Explanation of Symbols]

[0131] 1. Second polarizing film protective film 6 Polarizing film 7. First polarizing film protective film 8 molds 10. Resin film (film roll) 11 heating zones 12 Extension Zones 13 Cooling Zones 14. Winding (winding of polarizing protective film) 15 Extended Booths

Claims

1. A polarizing film protective film comprising an amorphous or microcrystalline polyamide resin, The retardation (Re) of the polarizing protective film is 3000 nm or more and 5000 nm or less. When the center line between the two sides of the polarizing protective film, which is nearly parallel to the slow-moving axis direction determined during the measurement of the retardation (Re) of the polarizing protective film, is defined as direction E1, The deviation of the slow axis at the center of the polarizing protective film, and the slow axis at positions 20 mm toward the center line from both sides of the polarizing protective film, from direction E1 is less than ±2.0°. A polarizing film protective film having a thickness (T1) of 150 μm or more and 270 μm or less.

2. A polarizing film protective film comprising an amorphous or microcrystalline polyamide resin, The retardation (Re) of the polarizing protective film is 3000 nm or more and 5000 nm or less. When the side of the film that is closest to being parallel to the slow-moving axis direction, which is determined when the retardation (Re) of the polarizing protective film is measured, is defined as the stretching direction E2, The deviation of the slow-moving axis at the center of the polarizing protective film, and the deviation of the slow-moving axis at a position 20 mm from each end of the polarizing protective film, from the stretching direction E2 is less than ±2.0° in both cases. A polarizing film protective film having a thickness (T1) of 150 μm or more and 270 μm or less.

3. The polarizing film protective film according to claim 1 or 2, wherein the amorphous or microcrystalline polyamide resin comprises a polyamide resin containing alicyclic diamine units and aliphatic dicarboxylic acid units having 7 to 20 carbon atoms.

4. The polarizing film protective film according to claim 3, wherein the alicyclic diamine unit comprises at least one represented by formula (PA-0). 【Chemistry 1】 (In formula (PA-0), R is an independent substituent, and n is an independent integer from 0 to 5. L is a single bond or a divalent linking group. * indicates a bond site with another unit or terminal group.)

5. The polarizing film protective film according to claim 1 or 2, wherein the thickness (T1) of the polarizing film protective film is 180 to 270 μm.

6. The polarizing film protective film according to claim 1 or 2, wherein the polarizing film protective film is a uniaxially oriented film.

7. The polarizing film protective film according to claim 1 or 2, wherein the length of the long side of the polarizing film protective film is 300 mm or more, and the length of the short side of the polarizing film protective film is 290 mm or more.

8. The amorphous or microcrystalline polyamide resin includes a polyamide resin containing alicyclic diamine units and aliphatic dicarboxylic acid units having 7 to 20 carbon atoms. The alicyclic diamine unit includes at least one represented by formula (PA-0), The thickness (T1) of the polarizing protective film is 180 to 270 μm. The polarizing film protective film according to claim 1, wherein the polarizing film protective film is a uniaxially oriented film, the length of the long side of the polarizing film protective film is 300 mm or more, and the length of the short side of the polarizing film protective film is 290 mm or more. 【Chemistry 2】 (In formula (PA-0), R is an independent substituent, and n is an independent integer from 0 to 5. L is a single bond or a divalent linking group. * indicates a bond site with another unit or terminal group.)

9. The polarizing film protective film according to claim 1, 2, or 8, wherein the haze of the polarizing film protective film, as measured according to JIS K 7136, is less than 1.0%.

10. A polarizing sheet having a first polarizing film protective film, a polarizing film, and a second polarizing film protective film in the order described above, A polarizing sheet in which the first polarizing film protective film is the polarizing film protective film according to claim 1, 2, or 8.

11. A polarizing sheet having a first polarizing film protective film, a polarizing film, and a second polarizing film protective film in the order described above, The first polarizing protective film comprises an amorphous or microcrystalline polyamide resin. The retardation (Re) of the first polarizing film protective film is 3000 nm or more and 5000 nm or less. When the center line between the two sides of the polarizing protective film, which is nearly parallel to the slow-moving axis direction determined during the measurement of the retardation (Re) of the polarizing protective film, is defined as direction E1, The deviation of the slow axis at the center of the polarizing protective film, and the slow axis at positions 20 mm toward the center line from both sides of the polarizing protective film, from direction E1 is less than ±2.0°, When the film edge that is closest to being parallel to the slow-moving axis direction, which is determined when measuring the retardation (Re) of the polarizing protective film, is defined as the stretching direction E2, The deviation of the slow-moving axis at the center of the polarizing protective film, and the deviation of the slow-moving axis at a position 20 mm from each end of the polarizing protective film, from the stretching direction E2 is less than ±2.0° in both cases. The thickness (T1) of the first polarizing film protective film is 150 μm or more and 270 μm or less. A polarizing sheet in which the ratio (T1 / T2) of the thickness (T1) of the first polarizing protective film to the thickness (T2) of the second polarizing protective film satisfies 1.0 < T1 / T2 < 1.

67.

12. The polarizing sheet according to claim 11, wherein the total thickness of the polarizing sheet is 270 μm or more and 535 μm or less.

13. A heat-bent molded polarizing sheet according to claim 11 or 12.

14. The heat-bent molded body according to claim 13, wherein the first polarizing film protective film side is a curved convex surface, and the second polarizing film side is a curved concave surface.

15. Sunglasses comprising a polarizing sheet according to claim 11 or 12.

16. A polarizing film protective film comprising an amorphous or microcrystalline polyamide resin, wherein the retardation (Re) of the polarizing film protective film is 3000 nm or more and 5000 nm or less. When the center line between the two sides of the polarizing protective film, which is nearly parallel to the slow-moving axis direction determined during the measurement of the retardation (Re) of the polarizing protective film, is defined as direction E1, The deviation of the slow axis at the center of the polarizing protective film, and the slow axis at positions 20 mm toward the center line from both sides of the polarizing protective film, from direction E1 is less than ±2.0°, When the side of the film that is closest to being parallel to the slow-moving axis direction, which is determined when the retardation (Re) of the polarizing protective film is measured, is defined as the stretching direction E2, The deviation of the slow-moving axis at the center of the polarizing protective film, and the deviation of the slow-moving axis at a position 20 mm from each end of the polarizing protective film, from the stretching direction E2 is less than ±2.0° in both cases. A method for manufacturing a polarizing film protective film, wherein the thickness (T1) of the polarizing film protective film is 150 μm or more and 270 μm or less, A method for manufacturing a polarizing film protective film, comprising uniaxial stretching of a polyamide resin film containing an amorphous or microcrystalline polyamide resin, wherein the stretching ratio is greater than 0 and less than or equal to 1.9 times.

17. A method for manufacturing a polarizing film protective film according to claim 16, wherein the stretching booth temperature during stretching is in the range of Tmg-15°C to Tmg+17°C, with reference to the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin.

18. A method for manufacturing a polarizing protective film according to claim 16 or 17, wherein the surface temperature of the stretching roll immediately before stretching during the stretching process is in the range of Tmg-15°C to Tmg-5°C, with reference to the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin.

19. The method for manufacturing a polarizing film protective film according to claim 16, wherein the polarizing film protective film is the polarizing film protective film according to claim 1, 2, or 8.

20. The stretching booth temperature during stretching is in the range of Tmg-15°C to Tmg+17°C, with respect to the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin. The surface temperature of the stretching roll immediately before stretching during the stretching process is in the range of Tmg-15°C to Tmg-5°C, with respect to the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin. The method for manufacturing a polarizing film protective film according to claim 16, wherein the polarizing film protective film is the polarizing film protective film according to claim 1, 2, or 8.

21. A method for producing a heat-bent molded article, comprising heat-bending the polarizing sheet according to claim 11 or 12 at a temperature of Tmg-12°C to Tmg-6°C, with reference to the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin contained in the first polarizing film protective film.

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