Polarizing film protective film, polarizing sheet, hot-bent molded body, sunglasses, method for producing polarizing film protective film, and method for producing hot-bent molded body

Abstract

Provided are: a polarizing film protective film; a polarizing sheet; a hot-bent molded body; sunglasses; a method for producing a polarizing film protective film; and a method for producing a hot-bent molded body. A polarizing film protective film according to the present disclosure contains an amorphous or microcrystalline polyamide resin. The retardation (Re) of the polarizing film protective film is 3,000 nm to 5,000 nm inclusive. If Nx and Ny are the in-plane three-dimensional refractive indexes of the polarizing film protective film, ||Nx - Ny|| is 1.80 × 10-2 or less, and the thickness (T1) of the polarizing film protective film is 150 µm to 270 µm inclusive.

Description

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

[0001] The present invention relates to polarizing film protective films, polarizing sheets, heat-bent molded articles, sunglasses, methods for manufacturing polarizing film protective films, and methods for manufacturing heat-bent molded articles. In particular, it relates to polarizing film protective films containing amorphous or microcrystalline polyamide resins.

[0002] Currently, commercially available polarizing sheets typically use 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] Here, when a polarizing sheet is used in applications requiring impact resistance, such as polarizing lenses for sunglasses, a polarizing film made using 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, heat-bent into a partially spherical shape, and subjected to appropriate surface treatment. For example, a polarizing sheet for such heat-bending is known, as described in Patent Document 1. On the other hand, when lenses using 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. Given these circumstances, a polarizing sheet using a polyamide resin film stretched to impart retardation and used as a protective film is 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.

[0006] Japanese Patent Publication No. 2003-145616, Japanese Patent Publication No. 2020-52406, Japanese Patent Publication No. 2011-180266, Japanese Patent Publication No. 2024-13669

[0007] As mentioned above, polarizing sheets using polyamide resin films have been studied. On the other hand, in recent years there has been a growing demand for thinner polarizing sheets. The inventors have found that as the polyamide resin film used in 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 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 lens-making process. However, the above-mentioned patent documents do not address this point at all. The present invention aims to solve these 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 that can provide a polarizing sheet that exhibits high retardation even with a thin thickness and in which the X-direction and Y-direction curves of the sheet surface during heat bending are easily aligned.

[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 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, and when the in-plane three-dimensional refractive indices of the polarizing film protective film are Nx and Ny, |Nx-Ny| is 1.80 x 10 －２ A polarizing film protective film having the following characteristics, wherein the thickness (T1) of the polarizing film protective film is 150 μm or more and 270 μm or less. [2] The polarizing film protective film according to [1], 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. [3] The polarizing film protective film according to [2], wherein the alicyclic diamine units comprise at least one represented by formula (PA-0). (In formula (PA-0), R is independently a substituent, and 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.) [4] The |Nx-Ny| of the polarizing film protective film is 0.50 x 10 －２ ~1.75 x 10 －２ A polarizing film protective film according to any one of [1] to [3]. [5] A 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] A 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 amorphous or microcrystalline polyamide resin comprises a polyamide resin containing alicyclic diamine units and aliphatic dicarboxylic acid units having 7 to 20 carbon atoms, wherein the alicyclic diamine units include at least one represented by formula (PA-0), and the |Nx-Ny| of the polarizing film protective film is 0.50 x 10 －２ ~1.70 x 10 －２ The polarizing film protective film according to any one of [1] to [6], wherein the thickness (T1) of the polarizing film protective film is 180 to 270 μm, and the polarizing film protective film is a uniaxially oriented film. (In formula (PA-0), R is independently a substituent, and 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.) [8] The polarizing film protective film according to any one of [1] to [7], wherein the haze of the polarizing film protective film measured according to JIS K 7136 is less than 1.0%. [9] 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 according to any one of [1] to [8].

[10] A polarizing sheet having a first polarizing protective film, a polarizing film, and a second polarizing protective film in the order described above, wherein the first polarizing protective film contains an amorphous or microcrystalline polyamide resin, the retardation (Re) of the first polarizing protective film is 3000 nm or more and 5000 nm or less, and when the in-plane three-dimensional refractive indices of the first polarizing protective film are Nx and Ny, |Nx-Ny| is 1.80 x 10 －２ A polarizing sheet that is as follows: The thickness (T1) of the first polarizing protective film is 150 μm or more and 270 μm or less; and 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.

[11] The second polarizing protective film contains amorphous or microcrystalline polyamide resin; the retardation (Re) of the second polarizing protective film is 2 nm or more and 500 nm or less; and when the in-plane three-dimensional refractive indices of the second polarizing protective film are Nx and Ny, |Nx - Ny| is 1.0 x 10 －３The polarizing sheet according to [9] or

[10] , wherein the thickness (T2) of the second polarizing protective film is 100 μm or more and 240 μm or less.

[12] The polarizing sheet according to any one of [9] to

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

[13] A heat-bent molded body of the polarizing sheet according to any one of [9] to

[12] .

[14] The heat-bent molded body according to

[13] , wherein the first polarizing 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 [9] to

[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, and when the in-plane three-dimensional refractive indices of the polarizing film protective film are Nx and Ny, |Nx - Ny| is 1.80 x 10 －２A 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, comprising uniaxial stretching of a resin film containing an amorphous or microcrystalline polyamide resin, wherein the stretching ratio is greater than 0 and less than 1.9.

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

[16] , wherein the temperature of the stretching booth during stretching is in the range of Tmg-15°C to Tmg+12°C, based on the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin.

[18] The 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, based on 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 [1] to [8], wherein the polarizing film protective film is the polarizing film protective film according to any one of

[16] to

[18] .

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

[16] to

[19] , wherein the temperature of the stretching booth during stretching is in the range of Tmg-15°C to Tmg+12°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 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, and the polarizing film protective film is the polarizing film protective film according to any one of [1] to [8]. A method for manufacturing a heat-bent molded article, comprising heat-bending a polarizing sheet described in any one of

[21] , [9], 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.

[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.

[0010] This is a schematic diagram illustrating a method for manufacturing a polarizing protective film. It is also a schematic diagram illustrating an example of the layer structure of a heat-bent molded body.

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

[0012] In this specification, preferred combinations of embodiments are considered more preferred embodiments. In this specification, all physical properties and characteristic values ​​are given at 23°C unless otherwise specified. In this specification, films and sheets refer to molded articles that are thin in thickness relative to their length and width, and are generally flat. In this specification, "film" and "sheet" may be single-layer or multi-layer. An example of a film is a single layer, and an example of a sheet is a multi-layer (e.g., 3 to 10 layers). 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 abolished as of January 1, 2024, the standards at the time of abolition shall apply. Figures 1 and 2 may not be consistent with reality in terms of scale, etc.

[0013] <Polarizing film protection film> The polarizing film protection film of this embodiment is a polarizing film protection film containing an amorphous or microcrystalline polyamide resin, wherein the retardation (Re) of the polarizing film protection film is 3000 nm or more and 5000 nm or less, and when the in-plane three-dimensional refractive indices of the polarizing film protection film are Nx and Ny, |Nx - Ny| is 1.80x10 －２The present invention relates to a polarizing protective film characterized in that the thickness (T1) of the polarizing protective film is 150 μm or more and 270 μm or less. With this configuration, 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. High retardation (Re) is required for polarizing protective films. This is required, for example, to ensure the functionality of sunglasses. To achieve such high retardation (Re), it is conceivable to stretch the polarizing protective film. The higher the stretching ratio, the easier it is for the polarizing protective film to exhibit high retardation (Re). However, the inventors have found that in films containing a thin polyamide resin, the higher the stretching ratio, the easier the film is to break, and the more difficult it is for the curves in the X direction and Y direction 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 direction and Y direction of the sheet surface during heat bending. Furthermore, when attempting to align the curves in the X direction and Y direction of the sheet surface during heat bending of a thin polarizing sheet, the heat bending temperature becomes high. From the viewpoint of the performance of the 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 below Tmg -4°C. In addition, given the actual conditions of the heat bending machine, there is a strong demand for the heat bending temperature to be below 145°C, and it is desirable that it be performed at a temperature of about 142°C ± 3°C. On the other hand, the above issues are less of a problem for thicker films, as high retardation can be achieved even at lower stretching ratios.

[0014] Under these circumstances, in this embodiment, a film has been found that is thin and has a small difference in the three-dimensional refractive index (|Nx-Ny|) within the plane of the polarizing film protective film, thereby achieving high retardation (Re) and good heat bending properties. That is, when a film is stretched (especially uniaxially stretched), the difference between the three-dimensional refractive index Nx and Ny within the plane of the polarizing film protective film usually becomes large. When such a polarizing film 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 has become possible to provide a polarizing film 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.

[0015] 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.

[0016] The polarizing protective film of this embodiment has a retardation (Re) of 3000 nm or more and 5000 nm or less. By having such a high retardation (Re), it can be used effectively as a polarizing sheet. The retardation (Re) is preferably 3400 nm or more, and may also be 4500 nm or less, or 4000 nm or less.

[0017] Furthermore, in this embodiment, when the three-dimensional refractive indices within the plane of the polarizing film protective film are Nx and Ny, |Nx - Ny| is 1.80 x 10 －２ The following applies. For example, when manufacturing a polarizing protective film using a roll, if the direction of the roll is Nx, then the direction of rotation of the roll is Ny. |Nx - Ny| represents the absolute value of Nx - Ny, but usually Nx - Ny ≥ 0. The above |Nx - Ny| is 1.75 x 10 －２It is preferably the following: 1.73 x 10 －２ More preferably, it is the following: 1.70 x 10 －２ Even more preferably, it is the following: 1.70 x 10 －２ Even more preferably, it is less than: 1.51 x 10 －２ Even more preferably, it is the following. Also, the lower limit value of the |Nx - Ny| is 0 or more. For example, 0.50 x 10 －２ or more, 0.70 x 10 －２ or more, 1.00 x 10 －２ or more is sufficient to fully satisfy the required performance.

[0018] Preferably, the Nx is 1.53 or less, and usually 1.51 or more. Preferably, the Ny is 1.52 or less, and usually 1.50 or more.

[0019] Also, in the polarizing film protective film of the present embodiment, preferably, the three-dimensional refractive index Nz in the thickness direction of the polarizing film protective film is 1.52 or less, and usually 1.50 or more.

[0020] The thickness (T1) of the polarizing film protective film of the present 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 220 μm or more, and also 270 μm or less, can be 250 μm or less, and further can be 245 μm or less. By setting the thickness (T1) of the polarizing film protective film to be the lower limit value or more, the retardation (Re) tends to be higher. Also, by setting the thickness (T1) of the polarizing film protective film to be the upper limit value or less, the curves in the X direction and the Y direction of the sheet surface during thermoforming tend to be more aligned.

[0021] The retardation (Re), three-dimensional refractive index, and thickness of the polarizing film protective film are measured according to the description of the examples described later (hereinafter, the same applies to the second polarizing film protective film).

[0022] As described above, in order to obtain a polarizing film protective film having a high retardation (Re), a low |Nx - Ny|, and a thin thickness, for example, it is exemplified that two or more of the following means are combined. (1) Stretching a resin film containing an amorphous or microcrystalline polyamide resin at a low draw ratio while achieving a thin thickness and a high retardation (Re). (2) Uniaxially stretching a resin film containing an amorphous or microcrystalline polyamide resin. (3) Devising the stretching temperature (booth temperature or the surface temperature of the stretching roll immediately before stretching) when stretching a resin film containing an amorphous or microcrystalline polyamide resin. These details will be described in the section on the manufacturing method of the polarizing film protective film described later. In the above Patent Document 3, no consideration has been given to the booth temperature or the roll temperature. Naturally, no consideration has been given to a polarizing sheet in which the curves in the X direction and the Y direction of the sheet surface during thermoforming are likely to be aligned. Furthermore, as a result of the inventor's investigation, it was found that the film described in the examples of Patent Document 3 becomes cloudy due to its thickness and draw ratio, and the haze exceeds 1.0% by far. On the other hand, the film described in Patent Document 4 is a film excellent in optical distortion, but no consideration has been given to a polarizing sheet in which the curves in the X direction and the Y direction of the sheet surface during thermoforming are likely to be aligned. For example, the film described in Example 7 of Patent Document 4 is obtained by cutting out a melt-extruded polyamide film into a 40 cm square and then stretching it batchwise, so it is very difficult to adjust the value of |Nx - Ny|. In particular, it is difficult to uniformly adjust the value of |Nx - Ny| over the entire film.

[0023] Therefore, the polarizing film protective film of the present embodiment may be a uniaxially stretched film or a biaxially stretched film, but a uniaxially stretched film is preferred.

[0024] <<Amorphous or Microcrystalline Polyamide Resin>> On the other hand, the polarizing film protective film of the present embodiment contains an amorphous or microcrystalline polyamide resin. By containing an amorphous or microcrystalline polyamide resin, a polarizing film protective film that is less susceptible to damage such as plasticizers and has excellent transparency can be obtained.

[0025] Here, amorphous or microcrystalline polyamide resin refers to a resin that does not have a distinct melting point, and specifically, a crystal melting enthalpy ΔHm of less than 5 J / g, preferably 3 J / g or less, and more preferably 1 J / g or less. The crystal melting enthalpy 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.

[0026] 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.

[0027] 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 preferably contains two or three or more substituted or unsubstituted cyclohexane rings, and even more preferably two substituted or unsubstituted cyclohexane rings. It is preferable that the alicyclic diamine unit 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.

[0028] In this embodiment, it is more preferable that the alicyclic diamine unit includes at least one represented by formula (PA-0). (In formula (PA-0), R is independently a substituent, and 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.) In formula (PA-0), 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 independently an integer from 0 to 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 a C1-C3 alkylene group, 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.

[0029] In this embodiment, it is more preferable that the alicyclic diamine unit is represented by formula (PA-1). (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.

[0030] In formula (PA-1), R １is 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 from 0 to 3, preferably an integer of 1 or more, preferably an integer of 2 or less, and even more preferably 0 or 1. In formula (PA-1), the first example of n1 is 0. In formula (PA-1), the second example of n1 is 1. When n1 is 1, R １ It is preferable that it be a methyl group.

[0031] 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.

[0032] 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 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.

[0033] 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 diamines having aromatic rings such as xylylenediamine, bis(4-aminophenyl) ether, paraphenylenediamine, and bis(aminomethyl)naphthalene. These can be used individually or in combination of two or more.

[0034] 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-(CH ２ ) ｎ It is preferable to represent it as -COOH, where n is an integer from 5 to 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.

[0035] 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.

[0036] Examples of dicarboxylic acids other than aliphatic dicarboxylic acids having 7 to 20 carbon atoms include phthalate compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid, and 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.

[0037] The amorphous or microcrystalline polyamide resin used in this embodiment may further contain aminocarboxylic acid units. Including aminocarboxylic acid units can further improve the hue of the resulting polarizing protective film. There is no particular 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 consists 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.

[0038] In this embodiment, the aminocarboxylic acid constituting the aminocarboxylic acid unit is preferably represented by formula (PA-2). (In formula (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 more, more preferably 7 or more, even more preferably 8 or more, even more preferably 9 or more, even more preferably 10 or more, 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.

[0039] It should be noted that amorphous or microcrystalline polyamide resins mainly contain diamine units and dicarboxylic acid units, but 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, amorphous or microcrystalline polyamide resins 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 included 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. The molar ratio of diamine units to dicarboxylic acid units in amorphous or microcrystalline polyamide resin is preferably 40:60 to 60:40, and more preferably 45:55 to 55:45. Furthermore, in this embodiment, it is preferable that the proportion of aminocarboxylic acid units among the total monomer units constituting the amorphous or microcrystalline polyamide resin is 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 the 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 the 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.

[0040] Amorphous or microcrystalline polyamide resin may also be made from polyamide resin produced using biomass raw materials (biomass polyamide resin). Using biomass polyamide resin can reduce the environmental impact. Amorphous or microcrystalline polyamide resin may also be made from monomer raw materials that have been certified under Mass Balance Certification (ISCC PLUS). Mass Balance Certification means that the extent to which renewable raw materials and bio-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.), rejected products, or scraps generated during the molding of amorphous or microcrystalline polyamide resin or the polarizing film protective film of this embodiment.

[0041] 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 film 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 later.

[0042] The content of amorphous or microcrystalline polyamide resin in the polarizing film protective film of this embodiment 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, the content of amorphous or microcrystalline polyamide resin in the polarizing film protective film of this embodiment 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.

[0043] <<Resins other than amorphous or microcrystalline polyamide resins, and other components>> The polarizing film protective film of this embodiment may or may not contain polyamide resins other than amorphous or microcrystalline polyamide resins. It may also contain or may not contain amorphous or microcrystalline thermoplastic resins other than amorphous or microcrystalline polyamide resins.

[0044] Examples of polyamide resins other than amorphous or microcrystalline polyamide resins include aliphatic polyamide resins other than amorphous or microcrystalline polyamide resins and aromatic 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, polyamide 612, etc. 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, xylylenediamine-based polyamide resins (MXD6, etc.), etc.

[0045] 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.

[0046] 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%.

[0047] The polarizing film protective film of this embodiment may contain an amorphous or microcrystalline thermoplastic resin other than an amorphous or microcrystalline polyamide resin. Examples of amorphous or microcrystalline thermoplastic resins other than amorphous or microcrystalline polyamide resins include polycarbonate resin and polymethyl methacrylate resin, with polycarbonate resin 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.

[0048] 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 amorphous or microcrystalline thermoplastic resins other than amorphous or microcrystalline polyamide resins (preferably polycarbonate resins), 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.

[0049] The polarizing film protective film of this embodiment may contain 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.

[0050] (Polyetheramide Elastomer) A polyetheramide elastomer is an elastomer containing a polyether structure and a polyamide structure. The polyetheramide elastomer used in this embodiment preferably contains a polyalkylene glycol block and a polyamide block. When 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 substantially does not contain an ester structure. Substantially does not contain an ester structure means that it is not a so-called polyester etheramide elastomer, and more specifically, the content of the ester structure 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.

[0051] Polyalkylene glycol blocks are -(alkylene group -O) ｎ２ It is preferable to represent it as - (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. A specific example of the above -(alkylene group -O)- is -(CH ２ O) -, -(CH ２ CH ２ O) -, -(CH ２ CH ２ CH ２ O)-,-(CH(CH ３ )CH ２O) -, -(CH ２ CH ２ CH ２ CH ２ O)-,-(C(CH ３ ) ２ CH ２ O) is an example, and combinations of two or more of these are also acceptable. The aforementioned -(alkylene group-O) ｎ２ In -, n2 is preferably 1 to 200, and more preferably 3 to 100. The polyalkylene glycol block preferably includes a polypropylene glycol (PPG) block and / or a polytetramethylene ether glycol (PTMG) block.

[0052] In this embodiment, the proportion of polyalkylene glycol blocks in the polyetheramide elastomer is preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 15 mol% or more, and even more preferably 20 mol% or more, based on 100 mol% of the total constituent units of the polyetheramide elastomer. Depending on the application, it may be 30 mol% or more, 40 mol% or more, 50 mol% or more, 60 mol% or more, or 65 mol% or more. Setting it above the lower limit tends to further improve the impact strength when added to amorphous or microcrystalline polyamide resins. Furthermore, in this embodiment, the proportion of polyalkylene glycol blocks in the polyetheramide elastomer is preferably 90 mol% or less, more preferably 85 mol% or less, even more preferably 80 mol% or less, and even more preferably 75 mol% or less, based on 100 mol% of the total constituent units of the polyetheramide elastomer. Setting it below the upper limit tends to make it more compatible with amorphous or microcrystalline polyamide resins. The polyetheramide elastomer may contain only one type of polyalkylene glycol 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.

[0053] The polyamide block is preferably represented as an aliphatic polyamide block, -(NH(CH ２ ) ｎ３C (=O) ｎ４ It 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 constituting an amorphous or microcrystalline polyamide resin, n5 is 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, |n5 - n3| is preferably 3 or less, and more preferably 2 or less. n4 is preferably 1 to 300, and more preferably 5 to 100.

[0054] 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 containing two or more types, it is preferable that the total amount is within the above range.

[0055] 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.

[0056] The weight-average molecular weight of the polyetheramide elastomer used in this embodiment is preferably 3,000 or more, more preferably 5,000 or more, preferably 100,000 or less, and more preferably 80,000 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).

[0057] 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. If two or more types are included, it is preferable that the total amount falls within the above range.

[0058] (Release Agent) The release agent that may be included in the polarizing film protective film of this embodiment is not particularly limited as long as it improves the release properties from metal, and for example, compounds 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 release properties from the roll surface and die inner surface to the film raw material are improved, effectively suppressing contamination of the first roll and the formation of a sharkskin-like texture on the film surface during film manufacturing, and furthermore, effectively suppressing the generation of die residue in the die slip area.

[0059] Fatty acid esters are typically composed of a fatty acid and an alcohol. Fatty acid amides, for example, are composed of a fatty acid and ammonia and / or an amine, 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 when at least one selected from the group consisting of fatty acid esters, fatty acid amides, and polyalkylene glycols is used in this embodiment, it is not limited to these.

[0060] 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 a film during molding, and tends to further suppress contamination of the first roll and the formation of a sharkskin-like texture on the film surface. Setting it below the upper limit improves compatibility with amorphous or microcrystalline polyamide resins and tends to effectively suppress the release agent itself from contaminating 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. The fatty acid may also be a saturated fatty acid or an unsaturated fatty acid. The fatty acid may also 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.

[0061] 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 COOH and has not been esterified). 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. Furthermore, 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 to 10-valent alcohol, and more preferably a 1 to 4-valent alcohol. The number of carbon atoms in the aliphatic alcohol is preferably 1 or more, 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.

[0062] 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.

[0063] 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.

[0064] Next, the details of fatty acid amides will be described. 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, fatty acid amides are preferably 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 preferably 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 preferably a saturated aliphatic amine. Furthermore, the aliphatic amine preferably has 1 to 10 amino groups in one molecule, and more preferably has 1 to 4 amino groups.

[0065] 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 an amino group (-NH ２ It is preferable that the fatty acid amide does not contain ). The molecular weight of the fatty acid amide is preferably 100 or more, and preferably 1000 or less.

[0066] 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.

[0067] Next, the details of polyalkylene glycol will be described. Preferably, the polyalkylene glycol 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.

[0068] 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 bleeding 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.

[0069] 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. Examples of other 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.

[0070] In this embodiment, the polyalkylene glycol may be modified at its terminal ends with any substituent. Furthermore, the modification of the terminal ends may be at only one end of the polyalkylene glycol or at both ends. Examples of optional substituents include carboxyl groups, hydroxyl groups, alkyl ethers, aryl ethers, aralkyl ethers, fatty acid esters, and aryl esters.

[0071] 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.

[0072] 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 and other alkylene glycol units. Polyethylene glycol or propylene glycol is preferred, and polypropylene glycol is more preferred from the viewpoint of ease of manufacture.

[0073] 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.

[0074] 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 content 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. Setting the release agent content below the upper limit tends to more effectively suppress a decrease in transparency, glass transition temperature, and toughness. The polarizing film protective film of this embodiment may contain only one type of release agent or two or more types. When two or more types are included, it is preferable that the total amount falls within the above range.

[0075] 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 of the other components, or it may contain two or more. If it contains two or more other components, it is preferable that the total amount is within the above range.

[0076] The shape of the polarizing 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 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 m 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. If the polarizing protective film in this embodiment is a uniaxially oriented film, it is preferable that the direction of the stretching axis is in the direction of the long side of the film. The polarizing protective film in this embodiment may be a winding body wound around a core material.

[0077] <Method for Manufacturing a Polarizing Film Protective Film> The method for manufacturing a polarizing film protective film according to this embodiment is 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, and when the in-plane three-dimensional refractive indices of the polarizing film protective film are Nx and Ny, |Nx-Ny| is 1.80 x 10 －２ The following is a method for manufacturing a polarizing protective film, wherein the thickness (T1) of the polarizing protective film is 150 μm or more and 270 μm or less, and the method includes uniaxial stretching of a resin film containing an amorphous or microcrystalline polyamide resin, wherein the stretching ratio is greater than 0 and less than 1.9. By performing uniaxial stretching in this way and reducing the stretching ratio, a polarizing protective film can be obtained that can provide a polarizing sheet in which the curve in the X direction and the curve in the Y direction of the sheet surface are easily aligned during heat bending while maintaining high retardation.

[0078] 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.

[0079] The temperature of the stretching booth during stretching is preferably in the range of Tmg-15°C to Tmg+12°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 temperature of the stretching booth during stretching is in the range of Tmg-15°C to Tmg+12°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. It is remarkable that the value of |Nx-Ny| can be adjusted by stretching the fibers at a temperature significantly lower than the glass transition temperature Tmg.

[0080] 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.

[0081] 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 manufacturing the polarizing film protective film of this embodiment, a resin film (raw material, reference numeral 10) containing amorphous or microcrystalline polyamide resin is stretched. Here, the composition of the resin film containing amorphous or microcrystalline polyamide resin, which is the raw material 10, is usually the same as the composition of the stretched film (i.e., the polarizing film protective film of this embodiment).

[0082] 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.

[0083] The unwound resin film 10 passes 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, in the configuration of Figure 1, the film is heated 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. By setting the surface temperature of the stretching roll (3R) immediately before stretching to above the lower limit, the film tends to break less during stretching. Also, by setting the surface temperature to below the upper limit, the film tends to stick less to the roll during stretching. The surface temperature of the stretching roll (3R) immediately before stretching is more preferably 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 because it allows for high transparency while keeping the retardation value low. The surface roll temperatures of rolls No. 1 (1R) and No. 2 (2R) can be determined as appropriate. The surface temperature of roll 1R is preferably Tmg-25°C or higher, based on the glass transition temperature Tmg of the amorphous or microcrystalline polyamide resin, and less than or equal to the surface temperature of the stretching roll (3R) immediately before stretching. Furthermore, the surface temperature of roll 2R is preferably higher than the surface temperature of roll 1R.

[0084] 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 1.9, preferably 0.5 or more, more preferably 1.0 or more, even more preferably 1.5 or more, and may be 1.6 or more, and may even be 1.7 or more, and preferably 1.8 or less. Setting the stretching ratio to be above the lower limit tends to increase the retardation (Re). Also, setting the stretching ratio 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 the heat bending process. In this embodiment, in particular, the value of |Nx-Ny| can be adjusted by performing roll stretching at the above stretching ratio. In batch stretching, even with adjustments to the stretching ratio, it is difficult to achieve uniform stretching across the entire film, making it challenging to adjust the |Nx-Ny| value to the desired range across the entire film. This is because, when stretching in a batch manner with only the four sides of the film held by clamps, strong necking is likely to occur in the unheld areas. In such cases, the values ​​of Nx and Ny change significantly within the plane, making it difficult to adjust the |Nx-Ny| value to the desired range.

[0085] In the embodiment shown in Figure 1, it is preferable that the temperature of the stretching booth 15 during stretching is in the range of Tmg-15°C to Tmg+12°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. Also, 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 be Tmg-10°C or higher, and more preferably Tmg+10°C or lower, even more preferably Tmg+5°C or lower, even more preferably Tmg+1°C or lower, and may be Tmg-5°C or lower.

[0086] In the cooling zone 13, which is sent after the stretching zone 12, the film 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. The surface roll temperatures of No. 5 roll (5R) and No. 6 roll (6R) can be determined as appropriate. Typically, the surface temperature of 5R is preferably below the surface temperature of 4R, and the surface temperature of 6R is preferably below the surface temperature of 5R. The stretched resin film 10 (polarizing film protective film) that has passed through the cooling zone 13 is wound onto a core material to form a winding body 14.

[0087] <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.

[0088] 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. Known polarizing films can be used, and examples include a polyvinyl alcohol (PVA) film on which iodine or a dichroic organic dye is adsorbed or impregnated.

[0089] 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 usually 1 μm or more, and usually 30 μm or less.

[0090] The first polarizing film protective film can be the polarizing film protective film of the embodiment described above, and the preferred range is the same. The second polarizing film protective film can be the same as the first polarizing film protective film, but one having the following characteristics is preferably used.

[0091] The second polarizing film protective film is preferably thinner than the first polarizing film protective film. Specifically, the ratio (T1 / T2) of the thickness of the first polarizing film protective film (T1) to the thickness of the second polarizing film protective film (T2) is preferably 1.0 < T1 / T2 < 1.67. By having such a configuration, a polarizing sheet with better heat bending processability can be obtained. The ratio (T1 / T2) is more preferably 1.60 or less, even more preferably 1.50 or less, even more preferably 1.40 or less, and may be 1.30 or less, and more preferably 1.10 or more, and may also be 1.15 or more, or 1.20 or more.

[0092] The second polarizing protective 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.

[0093] Furthermore, for the second polarizing protective film, when the three-dimensional refractive indices within the plane of the polarizing protective film are Nx and Ny, |Nx - Ny| is 1.0 x 10⁻¹⁰. －３ The following is preferable: The |Nx-Ny| is 0.8 x 10 －３ Preferably, it is 0.5 x 10 －３ It is more preferable that the following conditions are met. Also, the lower limit of |Nx-Ny| is 0 or greater, but for example, 0.1x10 －５ Even with these specifications, the required performance is sufficiently met.

[0094] The aforementioned Nx is preferably 1.52 or less, and is usually 1.50 or more. The aforementioned Ny is preferably 1.52 or less, and is usually 1.50 or more.

[0095] Furthermore, the second polarizing film protective film preferably has a three-dimensional refractive index Nz in the thickness direction of the polarizing film protective film of 1.52 or less, and is usually 1.50 or more.

[0096] The second polarizing protective film may or may not be stretched. In this embodiment, it is preferable that the second polarizing protective film is not stretched.

[0097] 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.

[0098] The retardation (Re), three-dimensional refractive index, and thickness of the second polarizing protective film are measured according to the examples described below.

[0099] 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 the 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.

[0100] The second polarizing film protective film may contain other components in addition to amorphous or microcrystalline polyamide resin, without departing from the spirit of the present invention. Examples of other components include polyetheramide elastomers, mold release agents, 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 second polarizing film protective film may be formulated with additives described in paragraphs 0047 to 0103 of International Publication No. 2021 / 241471 and additives described in paragraphs 0041 to 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.

[0101] 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 film (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 film (1) and (2) described in Japanese Patent No. 7350464, etc., and the details of these are incorporated herein.

[0102] 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%.

[0103] The polarizing sheet of this embodiment can be made thinner. The total thickness of the polarizing sheet of 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 making the total thickness of the polarizing sheet below the upper limit, the processing time during heat bending tends to be shortened. Also, by making the total thickness of the polarizing sheet above the lower limit, the handling during heat bending tends to be improved. Furthermore, if the polarizing sheet of this embodiment has a multilayer body consisting of 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.

[0104] 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.

[0105] The method for manufacturing the polarizing sheet is not particularly limited; for example, conventionally known methods can be used.

[0106] <Heat-bent molded body> 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 body for heat bending) of this embodiment in the manufacture of a heat-bent molded body, 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.

[0107] Furthermore, in this embodiment, the heat-bent molded body is obtained by positioning the polarizing sheet of this embodiment so that the first polarizing protective film 7 is 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.

[0108] In this embodiment, the heat-bent molded article is preferably heat-bent 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. Also, 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.

[0109] 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).

[0110] <Hard Coat Layer> The polarizing sheet and heat-bent molded article of this embodiment may have a hard coat layer on their surface. In particular, when the polarizing sheet and heat-bent molded article 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 curing or by active energy rays and then curing it. An example of a material (paint) that can be cured using active energy rays is a polarizing film protective film consisting of one or more monofunctional or polyfunctional (preferably 2 to 10-functional) (meth)acrylate monomers or oligomers, and preferably a polarizing film protective film containing a monofunctional or polyfunctional (preferably 2 to 10-functional) urethane (meth)acrylate oligomer. These polarizing film protective films preferably contain a photopolymerization initiator as a curing catalyst. Examples of thermosetting materials (paints) include polyorganosiloxane-based and crosslinked acrylic-based materials. Such polarizing protective films are commercially available as acrylic resin or polycarbonate resin films or sheets, and can be appropriately selected considering their suitability for 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, the contents of which are incorporated herein by reference.

[0111] 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.

[0112] The thickness of the hard coat layer is typically 1 to 10 μm.

[0113] <Applications> 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), a cover 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 for sunglasses.

[0114] The present invention will be described in more detail below with reference to examples. The materials, amounts used, proportions, processing content, processing procedures, etc., 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, etc., used in the examples are difficult to obtain due to discontinuation or other reasons, measurements can be taken using other instruments with equivalent performance.

[0115] 1. Raw materials: XE3805, manufactured by EMS, a polyamide resin synthesized from bis(4-amino-3-methylcyclohexyl)methane and dodecanediic acid, amorphous polyamide resin.

[0116] 2. Measurement of Glass Transition Temperature The midpoint 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 taken and the midpoint glass transition temperature (Tmg) was measured. Specifically, a differential scanning calorimetry device (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 midpoint glass transition temperature obtained from the obtained DSC curve was defined as the midpoint glass transition temperature (Tmg).

[0117] 3. Reference Examples 1 and 2 (Manufacturing of Unoriented Film) <Manufacturing of Film Roll> The above amorphous or microcrystalline polyamide resin (XE3805) was extruded in a molten state using a T-die melt extruder consisting of a vented single-screw extruder (manufactured by Shibaura Machinery Co., Ltd.) with a screw nominal diameter of 50 mm and screw L / D = 32, under conditions of a discharge rate of 50 kg / h and a screw rotation speed of 100 rpm. After being pressed together with the first and second rolls, the film was cooled and solidified to produce a film. The cylinder temperature and die temperature were 280°C, and the first and second roll temperatures were 120°C. The film roll was wound onto a core material to obtain a film roll. The thickness of the obtained films was 200 μm and 150 μm, respectively, for Reference Example 1 and Reference Example 2. Details of the first and second rolls used are as follows. - First roll: Manufactured by Shibaura Machine Co., Ltd., UM roll dimensions: outer diameter 250 mm x roll width 600 mm - 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.

[0118] 4. Examples A1 to A15, Comparative Examples A1 to A6 (Production of Polarizing Film Protective Film) <Production of Film Roll> The above amorphous or microcrystalline polyamide resin (XE3805) was extruded in a molten state using a T-die melt extruder consisting of a vented single-screw extruder (manufactured by Shibaura Machinery Co., Ltd.) with a screw nominal diameter of 50 mm and screw L / D = 32, at a discharge rate of 50 kg / h and a screw rotation speed of 100 rpm. After being pressed together with the first and second rolls, the film was cooled and solidified to produce a film. The cylinder temperature and die temperature were 280°C, and the surface temperature of the first and second rolls was 120°C. The film roll was wound onto a core material to obtain a 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 250 mm x roll width 600 mm • Second roll: Manufactured by Shibaura Machine Co., Ltd., rigid metal roll (surface: chrome plated) dimensions: outer diameter 250 mm x roll width 600 mm

[0119] <Stretching of the film roll> 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 No. 1 roll (1R), No. 2 roll (2R), and No. 3 roll (3R). The surface temperature of No. 1 roll was 130°C, the surface temperature of No. 2 roll was 135°C, and the surface temperature of No. 3 roll was the temperature shown in Table 1 (No. 3R temperature). After heating through No. 1 to No. 3 rolls, it was stretched in the stretching zone 12. The temperature of the stretching booth 15 in the stretching zone 12 and the stretching ratio (unit: times) were the values ​​shown in Table 1 (booth temperature, stretching ratio). After stretching, No. 4 roll (4R), No. 5 roll (5R), No. A stretched film (polarizing film protective film) was obtained by cooling the resin film 10 while passing it through six rolls (6R). 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 stretching ratio was adjusted to the values ​​shown in Table 1 by the difference in peripheral speed between rolls No. 4 and No. 3.

[0120]

[0121] The haze levels of all the films obtained as described above were less than 1.0% when measured according to JIS K 7136.

[0122] <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 average value of five measurements taken in the width direction of the obtained polarizing protective film and polarizing sheet was taken as the thickness value. Measurements were taken at a total of five points: two points at the film edge, one point in the center of the film, and two points midway between the edge and the center. A Mitutoyo MDC-25SX Digimatic standard outside micrometer was used as the measuring instrument. The unit of thickness for the polarizing protective film and polarizing sheet is given in μm.

[0123] <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 40 mm x 40 mm test piece was cut from two points on the film edge and one point in the center of the film, and Re was measured. The measurement was performed by setting the test piece in a phase difference / elliptic polarization measuring device (KOBRA-HBR, manufactured by Oji Instruments Co., Ltd.), and measuring the phase difference at a wavelength of 589.3 nm and an incident angle of 0° at one point in the center of the test piece film to determine Re. The results are shown in Table 2. The unit of retardation (Re) of the polarizing protective film is shown in nm.

[0124] <Measurement of Three-Dimensional Refractive Index in the Plane of Polarizing Protective Film> The average value of measurements taken at three locations in the width direction of the obtained polarizing protective film was used. Specifically, a 40 mm x 40 mm test piece was cut from two locations at the film edge and one location in the center of the film, and the three-dimensional refractive index 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 was measured at one point in the center of the test piece film at a wavelength of 589.3 nm and incident angles of 0°, 10°, 20°, 30°, 40°, and 50°. The three-dimensional refractive indices Nx, Ny, and Nz were calculated from the values ​​of the phase difference and incident angle. The refractive index of polyamide at that time was assumed to be 1.51. Subsequently, the average values ​​of the three-dimensional refractive indices Nx, Ny, and Nz from 10° to 50° were taken as Nx, Ny, and Nz. The average of the three cut test pieces was taken as the final Nx, Ny, and Nz. Nx is the refractive index in the in-plane slow axis direction, Ny is the refractive index perpendicular to the slow axis in the in-plane direction, and Nz is the refractive index in the thickness direction. |Nx - Ny| was calculated from the values ​​of Nx and Ny. The results are shown in Table 2.

[0125]

[0126] As is clear from the results above, the polarizing protective film of the present invention exhibited high retardation despite its thinness.

[0127] 5. Examples B1-B19, Comparative Examples B1-B6 (Production of Polarizing Sheets) <Preparation of Polarizing Films> A polyvinyl alcohol film (manufactured by Kuraray Co., Ltd.) was swollen in water at 35°C, then dyed in an aqueous solution at 35°C containing the dichroic dyes Kayaras 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. The film was then 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 four times its original size. The film was then heat-treated at 110°C for 3 minutes while maintaining tension to obtain a 30 μm polarizing film. The obtained polarizing film was stored in a low-humidity storage cabinet until the next process.

[0128] <Preparation of Polarizing Sheets> A two-component moisture-curing polyurethane adhesive (main component: Mitsui Chemicals, "Takelac A-520", curing agent: Mitsui Chemicals, "Takenate A-50") was applied to one side of the first film (first polarizing film protective film) shown in Table 3 or Table 4, and laminated with the polarizing film obtained above, aligning the stretch axis. The remaining side of the polarizing film was laminated in the same manner using the second film (second polarizing film protective film) shown in Table 3 or Table 4. After lamination, the adhesive was cured by leaving it in a constant temperature bath at 70°C to obtain polarizing sheets. The thickness of the adhesive was 10 μm in each case.

[0129] <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 mold and heat-bent by pressing a convex mold against it for 2 minutes while vacuum suction was applied from a suction hole provided at the bottom of the concave mold. The concave and convex molds were controlled to 140°C and 142°C, respectively, during processing. The curve value in the X direction of the obtained bent polarizing sheet was defined as the X-curve, and the curve value in the Y direction was defined as the Y-curve, and measured using a RADIUS GAUGE (Carton Optical Co., Ltd., part number 591, corresponding to refractive index 1.525). The results are shown in Table 3 or Table 4.

[0130]

[0131]

[0132] In Tables 3 and 4 above, nd. indicates that there is no data. As is clear from the above results, 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.

[0133] 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.

[0134] 1. Second polarizing film protective film 6. Polarizing film 7. First polarizing film protective film 8. Mold 10. Resin film (film raw material) 11. Heating zone 12. Stretching zone 13. Cooling zone 14. Winding body (winding body of polarizing film protective film) 15. Stretching booth

Claims

1. 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, and when the in-plane three-dimensional refractive indices of the polarizing film protective film are Nx and Ny, |Nx - Ny| is 1.80 x 10⁻¹⁰ －２ A polarizing film protective film having the following characteristics, wherein the thickness (T1) of the polarizing film protective film is 150 μm or more and 270 μm or less.

2. The polarizing film protective film according to claim 1, 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.

3. The polarizing film protective film according to claim 2, wherein the alicyclic diamine unit comprises at least one represented by formula (PA-0). (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.) 4. The |Nx-Ny| of the polarizing protective film is 0.50 x 10 －２ ~1.75 x 10 －２ A polarizing film protective film according to any one of claims 1 to 3.

5. The polarizing film protective film according to any one of claims 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 claims 1 to 5, wherein the polarizing film protective film is a uniaxially oriented film.

7. 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, the alicyclic diamine units comprise at least one represented by formula (PA-0), and the |Nx-Ny| of the polarizing film protective film is 0.50 x 10 －２ ~1.70 x 10 －２ The polarizing film protective film according to any one of claims 1 to 6, wherein the thickness (T1) of the polarizing film protective film is 180 to 270 μm, and the polarizing film protective film is a uniaxially oriented film. (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.) 8. The polarizing film protective film according to any one of claims 1 to 7, wherein the haze of the polarizing film protective film measured according to JIS K 7136 is less than 1.0%.

9. 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 described in any one of claims 1 to 8.

10. A polarizing sheet having a first polarizing protective film, a polarizing film, and a second polarizing protective film in the order described above, wherein the first polarizing protective film contains an amorphous or microcrystalline polyamide resin, the retardation (Re) of the first polarizing protective film is 3000 nm or more and 5000 nm or less, and when the in-plane three-dimensional refractive indices of the first polarizing protective film are Nx and Ny, |Nx-Ny| is 1.80 x 10⁻¹⁰ －２ A polarizing sheet that is as follows: the thickness (T1) of the first polarizing protective film is 150 μm or more and 270 μm or less; and 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.

11. The second polarizing protective film comprises an amorphous or microcrystalline polyamide resin, the retardation (Re) of the second polarizing protective film is 2 nm or more and 500 nm or less, and when the in-plane three-dimensional refractive indices of the second polarizing protective film are Nx and Ny, |Nx - Ny| is 1.0 x 10⁻¹⁰. －３ The polarizing sheet according to claim 9 or 10, wherein the thickness (T2) of the second polarizing film protective film is 100 μm or more and 240 μm or less.

12. The polarizing sheet according to any one of claims 9 to 11, wherein the total thickness of the polarizing sheet is 270 μm or more and 535 μm or less.

13. A heat-bent molded body of a polarizing sheet according to any one of claims 9 to 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 any one of claims 9 to 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, and when the in-plane three-dimensional refractive indices of the polarizing film protective film are Nx and Ny, |Nx - Ny| is 1.80 x 10⁻¹⁰ －２ 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, comprising uniaxial stretching of a resin film containing an amorphous or microcrystalline polyamide resin, wherein the stretching ratio is greater than 0 and less than 1.

9.

17. The method for manufacturing a polarizing film protective film according to claim 16, wherein the temperature of the stretching booth during stretching is in the range of Tmg-15°C to Tmg+12°C, with reference to the glass transition temperature Tmg measured according to differential scanning calorimetry of the amorphous or microcrystalline polyamide resin.

18. The method for manufacturing a polarizing film protective film according to claim 16 or 17, wherein the surface temperature of the stretching roll immediately before 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 claims 16 to 18, wherein the polarizing film protective film is the polarizing film protective film according to any one of claims 1 to 8.

20. The method for manufacturing a polarizing film protective film according to any one of claims 16 to 19, wherein the temperature of the stretching booth during stretching is in the range of Tmg-15°C to Tmg+12°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 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, and the polarizing film protective film is the polarizing film protective film according to any one of claims 1 to 8.

21. A method for manufacturing a heat-bent molded article, comprising heat-bending a polarizing sheet according to any one of claims 9 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.

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