Method for producing resin film and processed film

Abstract

To provide a resin film capable of suppressing an occurrence of a crack extending in a direction orthogonal to a thickness direction when processing an outer shape.SOLUTION: The resin film has a shear fracture strength of 2.5 N or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a resin film and a processed film. [Background technology]

[0002] Resin films are widely used in various industrial products and are generally processed into shapes according to their intended use. For example, it has been proposed to process an acrylic resin film into a desired shape (see, for example, Patent Document 1). However, when the acrylic resin film described in Patent Document 1 is processed into its outer shape, cracks extending in a direction perpendicular to the thickness direction may occur on the edge surfaces of the acrylic resin film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-213401 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made to solve the above-mentioned conventional problems, and its main object is to provide a resin film that can suppress the occurrence of cracks extending perpendicular to the thickness direction during contour processing. [Means for solving the problem]

[0005] [1] The shear breaking strength of the resin film according to one embodiment of the present invention is 2.5 N or more. [2] The resin film described in [1] above may be made of a polycarbonate resin. [3] In a method for producing a processed film according to another aspect of the present invention, the resin film described in [1] or [2] above is processed into an outer shape. [Effects of the Invention]

[0006] According to an embodiment of the present invention, a resin film can be realized that can suppress the occurrence of cracks extending in a direction perpendicular to the thickness direction during contour processing. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic cross-sectional view of a resin film according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view of one embodiment of a polarizing plate including the resin film of FIG. [Figure 3] FIG. 3 is a schematic cross-sectional view of another embodiment of a polarizing plate including the resin film of FIG. [Figure 4] FIG. 4 is a schematic plan view of a processed film produced from the resin film of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Representative embodiments of the present invention will be described below, but the present invention is not limited to these embodiments. In addition, in order to clarify the explanation, the width, thickness, shape, etc. of each part may be shown schematically in the drawings compared to the embodiments, but these are merely examples and do not limit the interpretation of the present invention.

[0009] (Definition of terms and symbols) The definitions of terms and symbols used in this specification are as follows. (1) Refractive index (nx, ny, nz) "nx" is the refractive index in the direction in which the in-plane refractive index is greatest (i.e., the slow axis direction), "ny" is the refractive index in the direction perpendicular to the slow axis in the plane (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction. (2) In-plane phase difference (Re) "Re(λ)" is the in-plane retardation measured with light of wavelength λ nm at 23°C. For example, "Re(550)" is the in-plane retardation measured with light of wavelength 550 nm at 23°C. Re(λ) is calculated by the formula: Re(λ)=(nx-ny)×d, where d (nm) is the thickness of the layer (film). (3) Retardation in the thickness direction (Rth) "Rth(λ)" is the retardation in the thickness direction measured with light of wavelength λ nm at 23°C. For example, "Rth(550)" is the retardation in the thickness direction measured with light of wavelength 550 nm at 23°C. Rth(λ) is calculated by the formula: Rth(λ) = (nx - nz) × d, where d (nm) is the thickness of the layer (film).

[0010] A. Overall structure of resin film FIG. 1 is a schematic cross-sectional view of a resin film according to one embodiment of the present invention. 1, the shear fracture strength (the force required to cut and fracture a sample) of the resin film 1 is 2.5 N or more. If the shear fracture strength of the resin film is 2.5 N or more, even when the resin film is subjected to the outline processing described below, it is possible to suppress the occurrence of cracks extending in a direction perpendicular to the thickness direction (lateral direction) on the edge surface of the resin film (processed film) after the outline processing.

[0011] The shear fracture strength of the resin film 1 is preferably 3.0 N or more, more preferably 3.5 N or more. On the other hand, the shear fracture strength of the resin film 1 is, for example, 7.0 N or less, preferably 6.0 N or less, more preferably 5.0 N or less. The shear fracture strength is measured, for example, in accordance with the JIS surface-interface cutting method (SAICAS method). If the shear fracture strength of the resin film is within this range, cracks extending in directions perpendicular to the thickness direction (plane direction, lateral direction) can be more stably suppressed at the end faces of the resin film (processed film) after contour processing. Furthermore, if the shear fracture strength of the resin film is below this upper limit, the resin film can be processed smoothly.

[0012] The Charpy tensile impact strength of the resin film 1 is, for example, 300 kJ / m 2 More than 400kJ / m 2 On the other hand, the Charpy tensile impact strength of the resin film 1 is, for example, 700 kJ / m 2 Less than or equal to 600 kJ / m 2 Less than or equal to 500 kJ / m 2 The Charpy tensile impact strength is measured, for example, in accordance with JIS K 7160. If the Charpy tensile impact strength of the resin film is within this range, it is possible to prevent cracks from occurring in the thickness direction (longitudinal direction) on the edge surfaces of the resin film (processed film) after contour processing.

[0013] The thickness of the resin film 1 is, for example, 10 μm or more, preferably 30 μm or more, and more preferably 40 μm or more. On the other hand, the thickness of the resin film 1 is, for example, 130 μm or less, preferably 100 μm or less, and more preferably 80 μm or less. If the thickness of the resin film is within this range, the occurrence of cracks during contour processing can be stably suppressed.

[0014] The resin film will be described in detail below.

[0015] B. Resin film The resin film 1 contains any suitable resin material as a main component. Specific examples of the resin material include transparent resins such as cycloolefin (COP) resins such as polynorbornene resins; polyester resins such as polyethylene terephthalate (PET) resins; cellulose resins such as triacetyl cellulose (TAC); polycarbonate (PC) resins; (meth)acrylic resins; polyvinyl alcohol resins; polyamide resins; polyimide resins; polyethersulfone resins; polysulfone resins; polystyrene resins; polyolefin resins; and acetate resins. Other examples include thermosetting or ultraviolet-curing resins such as (meth)acrylic resins, urethane resins, (meth)acrylic urethane resins, epoxy resins, and silicone resins. The term "(meth)acrylic resin" refers to acrylic resins and / or methacrylic resins. Other examples include glassy polymers such as siloxane polymers. The polymer films described in JP 2001-343529 A (WO 01 / 37007) can also be used. Examples of materials for this film include resin compositions containing a thermoplastic resin with substituted or unsubstituted imide groups in its side chains and a thermoplastic resin with substituted or unsubstituted phenyl and nitrile groups in its side chains. Examples include a resin composition containing an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile-styrene copolymer. The polymer film can be, for example, an extrusion molded product of the above resin composition. The resin film materials can be used alone or in combination.

[0016] Of these resin materials, PC resins are preferred.

[0017] PC resins contain at least structural units derived from dihydroxy compounds having a bond structure represented by the following structural formula (1), and are produced by reacting a dihydroxy compound containing at least one dihydroxy compound having at least one -CH2-O- bond in the molecule with a carbonate diester in the presence of a polymerization catalyst. In other words, PC resins contain structural units derived from dihydroxy compounds and carbonate groups derived from carbonate diesters. [ka]

[0018] Here, the dihydroxy compound having the bond structure represented by structural formula (1) can be any compound having any structure, as long as it has two alcoholic hydroxyl groups, contains a structure having a linking group -CH-O- in the molecule, and is capable of reacting with a carbonate diester in the presence of a polymerization catalyst to produce a polycarbonate, and multiple types may be used in combination.

[0019] Furthermore, a dihydroxy compound not having the bond structure represented by the structural formula (1) may be used in combination with the dihydroxy compound used in the PC resin. Hereinafter, a dihydroxy compound having the bond structure represented by the structural formula (1) may be abbreviated as dihydroxy compound (A), and a dihydroxy compound not having the bond structure represented by the structural formula (1) may be abbreviated as dihydroxy compound (B).

[0020] (Dihydroxy compound (A)) The "linking group -CH2-O-" in the dihydroxy compound (A) means a structure in which atoms other than hydrogen atoms are bonded to form a molecule. In this linking group, the atom to which at least an oxygen atom can be bonded or the atom to which both a carbon atom and an oxygen atom can be bonded is preferably a carbon atom. The number of "linking groups -CH2-O-" in the dihydroxy compound (A) is preferably 1 or more, more preferably 2 to 4.

[0021] Specific examples of the dihydroxy compound (A) include 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-methylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isopropylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isobutylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butylphenyl)fluorene, and 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene. a compound having an aromatic group in a side chain and an ether group bonded to the aromatic group in the main chain, such as 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3,5-dimethylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butyl-6-methylphenyl)fluorene, or 9,9-bis(4-(3-hydroxy-2,2-dimethylpropoxy)phenyl)fluorene;Bis[4-(2-hydroxyethoxy)phenyl]methane, bis[4-(2-hydroxyethoxy)phenyl]diphenylmethane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]ethane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]-1-phenylethane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane, 2,2-bis[4-(2-hydroxyethoxy)-3-methylphenyl]propane, 2,2-bis[3,5-dimethyl-4-(2-hydroxyethoxy)phenyl]propane 1,1-bis[4-(2-hydroxyethoxy)phenyl]propane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]-3,3,5-trimethylcyclohexane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 1,4-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 1,3-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 2,2-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]propane, 2,2-bis[(2-hydroxyethoxy)-3- isopropylphenyl]propane, 2,2-bis[3-tert-butyl-4-(2-hydroxyethoxy)phenyl]propane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]butane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]-4-methylpentane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]octane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]decane, 2,2-bis[3-bromo-4-(2-hydroxyethoxy)phenyl]propane bis(hydroxyalkoxyaryl)alkanes, such as 2,2-bis[3-cyclohexyl-4-(2-hydroxyethoxy)phenyl]propane; bis(hydroxyalkoxyaryl)cycloalkanes, such as 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 1,1-bis[3-cyclohexyl-4-(2-hydroxyethoxy)phenyl]cyclohexane, and 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclopentane;Dihydroxyalkoxy diaryl ethers, such as 4,4'-bis(2-hydroxyethoxy)diphenyl ether and 4,4'-bis(2-hydroxyethoxy)-3,3'-dimethyldiphenyl ether; bishydroxyalkoxy aryl sulfides, such as 4,4'-bis(2-hydroxyethoxyphenyl) sulfide and 4,4'-bis[4-(2-dihydroxyethoxy)-3-methylphenyl] sulfide; bishydroxyalkoxy aryl sulfoxides, such as 4,4'-bis(2-hydroxyethoxyphenyl) sulfoxide and 4,4'-bis[4-(2-dihydroxyethoxy)-3-methylphenyl] sulfoxide; 4,4'-bis(2-hydroxyethoxyphenyl) sulfone, 4,4'-bis[4-(2- Examples of the dihydroxy compound (A) include bishydroxyalkoxyarylsulfones, such as 1,4-bishydroxyethoxybenzene; bishydroxyalkoxybenzenes, such as 1,4-bishydroxyethoxybenzene; 1,3-bis[2-[4-(2-hydroxyethoxy)phenyl]propyl]benzene; 1,4-bis[2-[4-(2-hydroxyethoxy)phenyl]propyl]benzene; 4,4'-bis(2-hydroxyethoxy)biphenyl; 1,3-bis[4-(2-hydroxyethoxy)phenyl]-5,7-dimethyladamantane; anhydrosugar alcohols, such as the dihydroxy compound represented by the following formula (2); and compounds having a cyclic ether structure, such as the spiroglycol represented by the following general formula (3). The dihydroxy compound (A) may be used alone or in combination.

[0022] [ka]

[0023] [ka]

[0024] Of these dihydroxy compounds (A), preferred is the dihydroxy compound represented by the above formula (2). Examples of the dihydroxy compound represented by the above formula (2) include isosorbide, isomannide, and isoidet, which are stereoisomers, and these may be used alone or in combination of two or more. Among the dihydroxy compounds (A), isosorbide, which is obtained by dehydration condensation of sorbitol produced from various starches that are abundant and easily available as resources, is most preferred in terms of availability, ease of production, optical properties, and moldability.

[0025] The proportion of the structural units derived from the dihydroxy compound (A) relative to all structural units derived from dihydroxy compounds contained in the PC resin is, for example, 10 mol% or more, preferably 40 mol% or more, and more preferably 60 mol% or more. On the other hand, the proportion of the structural units derived from the dihydroxy compound (A) is, for example, 100 mol% or less, preferably 90 mol% or less, more preferably 80 mol% or less, and even more preferably 70 mol% or less. When the proportion of the dihydroxy compound (A) is within the above range, the shear breaking strength of the resin film can be stably adjusted to be within the above range.

[0026] (Dihydroxy compound (B)) As the dihydroxy compound that forms the structural unit of the PC resin, dihydroxy compound (A) and dihydroxy compound (B) can be used together. By using dihydroxy compounds (A) and (B) in combination, the shear breaking strength of the resin film can be more stably adjusted to fall within the above range.

[0027] The dihydroxy compound (B) is typically a dihydroxy compound other than the dihydroxy compound (A). Examples of the dihydroxy compound (B) include alicyclic dihydroxy compounds, aliphatic dihydroxy compounds, oxyalkylene glycols, aromatic dihydroxy compounds, and diols having a cyclic ether structure. The dihydroxy compounds (B) may be used alone or in combination. Of the dihydroxy compounds (B), preferred are alicyclic dihydroxy compounds.

[0028] The alicyclic dihydroxy compound is not particularly limited, but preferably includes a compound having a five-membered ring structure or a six-membered ring structure. The six-membered ring structure may be fixed in a chair or boat shape by a covalent bond. The five-membered or six-membered ring structure of the alicyclic dihydroxy compound can improve the heat resistance of the resulting PC resin. The number of carbon atoms contained in the alicyclic dihydroxy compound is, for example, 70 or less, preferably 50 or less, and more preferably 30 or less.

[0029] Specific examples of the alicyclic dihydroxy compound containing a 5-membered ring structure or a 6-membered ring structure include alicyclic dihydroxy compounds represented by the following general formula (I) or (II). HOCH2-R 1 -CH2OH (I) HO-R 2 -OH (II) (In formulas (I) and (II), R 1 and R 2 Each of the represents a cycloalkylene group having 4 to 20 carbon atoms.

[0030] Cyclohexanedimethanol, which is an alicyclic dihydroxy compound represented by the general formula (I), is a compound represented by the general formula (I) in which R 1 is represented by the following general formula (Ia) (wherein R 3 represents an alkyl group having 1 to 12 carbon atoms or a hydrogen atom. Specific examples of such isomers include 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, and 1,4-cyclohexanedimethanol.

[0031] [ka]

[0032] The alicyclic dihydroxy compound represented by the general formula (I), tricyclodecane dimethanol or pentacyclopentadecanedimethanol, is a compound represented by the general formula (I), 1 The compound includes various isomers represented by the following general formula (Ib) (wherein n is 0 or 1).

[0033] [ka]

[0034] Decalin dimethanol or tricyclotetradecane dimethanol, which is an alicyclic dihydroxy compound represented by the above general formula (I), is a compound represented by the general formula (I) in which R 1 is represented by the following general formula (Ic) (wherein m is 0 or 1). Specific examples of such isomers include 2,6-decalin dimethanol, 1,5-decalin dimethanol, and 2,3-decalin dimethanol.

[0035] [ka]

[0036] Norbornane dimethanol, which is an alicyclic dihydroxy compound represented by the above general formula (I), is a compound represented by the general formula (I) in which R 1 The isomers include various isomers represented by the following general formula (Id): Specific examples of such isomers include 2,3-norbornane dimethanol and 2,5-norbornane dimethanol.

[0037] [ka]

[0038] Adamantane dimethanol, which is an alicyclic dihydroxy compound represented by general formula (I), is 1The general formula (Ie) includes various isomers represented by the following general formula (Ie): Specific example of such isomer is 1,3-adamantanedimethanol.

[0039] [ka]

[0040] The cyclohexanediol, which is an alicyclic dihydroxy compound represented by the general formula (II), is a compound represented by the general formula (II) in which R 2 is represented by the following general formula (IIa) (wherein R 3 represents an alkyl group having 1 to 12 carbon atoms or a hydrogen atom. Specific examples of such isomers include 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, and 2-methyl-1,4-cyclohexanediol.

[0041] [ka]

[0042] The alicyclic dihydroxy compound represented by the general formula (II), tricyclodecanediol or pentacyclopentadecanediol, is a compound represented by the general formula (II), 2 includes various isomers represented by the following general formula (IIb) (wherein n is 0 or 1).

[0043] [ka]

[0044] Decalindiol or tricyclotetradecanediol, which is an alicyclic dihydroxy compound represented by the above general formula (II), is a compound represented by the general formula (II) in which R 2is represented by the following general formula (IIc) (wherein m is 0 or 1). Specific examples of such isomers include 2,6-decalindiol, 1,5-decalindiol, and 2,3-decalindiol.

[0045] [ka]

[0046] Norbornanediol, which is an alicyclic dihydroxy compound represented by the above general formula (II), is 2 The isomers include various isomers represented by the following general formula (IId): Specific examples of such isomers include 2,3-norbornanediol and 2,5-norbornanediol.

[0047] [ka]

[0048] Adamantanediol, which is an alicyclic dihydroxy compound represented by the general formula (II), is a compound represented by the general formula (II) in which R 2 These include various isomers represented by the following general formula (IIe): Specific examples of such isomers include 1,3-adamantanediol.

[0049] [ka]

[0050] Among the specific examples of the alicyclic dihydroxy compound described above, preferred are cyclohexanedimethanols, tricyclodecane dimethanols, adamantanediols, and pentacyclopentadecanedimethanols. From the viewpoints of availability and ease of handling, more preferred are 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, and tricyclodecane dimethanol, and even more preferred is tricyclodecane dimethanol.

[0051] The proportion of the structural units derived from the dihydroxy compound (B) relative to all structural units derived from dihydroxy compounds contained in the PC resin is, for example, 0 mol% or more, preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 30 mol% or more. On the other hand, the proportion of the structural units derived from the dihydroxy compound (B) is, for example, 90 mol% or less, preferably 60 mol% or less, and more preferably 40 mol% or less.

[0052] Details of these PC resins are described, for example, in JP 2012-31370 A (Patent No. 5448264), the disclosure of which is incorporated herein by reference.

[0053] In one embodiment, the PC resin contains a structural unit derived from the dihydroxy compound (A) represented by the above formula (2), a structural unit derived from the alicyclic dihydroxy compound (B) represented by the above general formula (I), and a carbonate group linking them. When a PC resin containing these structural units is used in a resin film, the shear breaking strength of the resin film can be more stably adjusted to fall within the above range. In such a PC resin, the molar ratio (A:B) of the structural units derived from the dihydroxy compound (A) represented by the above formula (2) to the structural units derived from the alicyclic dihydroxy compound (B) represented by the above general formula (I) is, for example, 5:5 to 9:1, and preferably 6:4 to 8:2. In such a PC resin, the combination of the dihydroxy compound (A) represented by the above formula (2) and the alicyclic dihydroxy compound (B) represented by the above general formula (I) is preferably a combination of isosorbide and tricyclodecane dimethanol.

[0054] The resin film 1 may contain any appropriate additives in addition to the resin materials described above. Examples of additives include antioxidants, UV absorbers, light stabilizers, nucleating agents, fillers, pigments, surfactants, and antistatic agents. Any appropriate surface treatment layer may be provided on the surface of the resin film 1. Examples of surface treatment layers include a hard coat layer, an easy-adhesion layer, an easy-slip layer, an antiblocking layer, an antistatic layer, an antireflection layer, and an anti-oligomer layer.

[0055] The resin film 1 is typically optically isotropic. In this specification, "optically isotropic" means that the in-plane retardation Re(550) and the thickness direction retardation Rth(550) are in the following ranges. The in-plane retardation Re(550) of the resin film 1 is, for example, 10 nm or less, preferably 5 nm or less, and more preferably 3 nm or less. On the other hand, the lower limit of the in-plane retardation Re(550) of the resin film 1 is typically 0 nm. The resin film 1 has a thickness direction retardation Rth(550) of, for example, −10 nm to +10 nm, and preferably −5 nm to +5 nm.

[0056] The resin film 1 has a total light transmittance of, for example, 80% or more, preferably 85% or more, more preferably 90% or more, and even more preferably 95% or more. The haze value of the resin film 1 is, for example, 2.0% or less, preferably 1.5% or less, more preferably 1.0% or less, even more preferably 0.7% or less, particularly preferably 0.5% or less, and particularly preferably 0.3% or less. The lower limit of the haze value of the resin film 1 is typically 0.05%. If the total light transmittance and / or haze value of the resin film is within this range, the resin film can be suitably used for optical applications.

[0057] C. Uses of resin film The resin films described in the above items A and B can be applied to various industrial products, such as optical components such as polarizing plates, decorative films, and product protection films. The above-mentioned resin film is particularly suitable for use in polarizing plates and decorative films.

[0058] C-1.Decorative film Although not shown, in one embodiment, the resin film 1 is used as a decorative film. More specifically, the resin film 1 can be used as a substrate for the decorative film. The decorative film includes the resin film 1 as a substrate, an adhesive layer provided on one surface of the resin film 1, and a printed layer provided on the surface of the adhesive layer opposite the substrate. Such a decorative film is attached to the surface of an adherend so that the printed layer is in contact with the adherend. The decorative film is then heated as needed and then peeled off from the surface of the adherend. The printed layer is then transferred to the surface of the adherend, allowing the adherend to be given a desired design.

[0059] C-2.Polarizing plate 2 and 3, the resin film 1 may be applied to a polarizing plate 100. More specifically, the resin film 1 may be employed as a protective layer for a polarizer 2. The polarizing plate 100 includes a polarizer 2 and a resin film 1 serving as a protective layer. The resin film 1 is disposed on at least one side of the polarizer 2. The resin film 1 is typically attached to the polarizer 2 via any appropriate adhesive layer (adhesive layer or pressure-sensitive adhesive layer). As shown in FIG. 3, the resin film 1 serving as a protective layer may be provided on both sides of the polarizer 2.

[0060] C-2-1.Polarizer Any appropriate polarizer can be adopted as the polarizer 2. For example, the resin film forming the polarizer may be composed of a single-layer resin film, or may be prepared using a laminate of two or more layers.

[0061] Specific examples of polarizers made of a single-layer resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene-vinyl acetate copolymer films that have been dyed with iodine or a dichroic substance such as a dichroic dye and stretched, as well as polyene-based oriented films such as dehydrated PVA films and dehydrochlorinated polyvinyl chloride films. Polarizers obtained by dyeing PVA films with iodine and uniaxially stretching them are preferred because of their excellent optical properties.

[0062] Specific examples of polarizers obtained using laminates include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate. A polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate can be produced, for example, by applying a PVA-based resin solution to the resin substrate and drying the resin substrate to form a PVA-based resin layer on the resin substrate, thereby obtaining a laminate of the resin substrate and the PVA-based resin layer, and then stretching and dyeing the laminate to convert the PVA-based resin layer into a polarizer. In one embodiment of the present invention, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin is preferably formed on one side of the resin substrate. Stretching typically involves immersing the laminate in an aqueous boric acid solution and stretching it. Furthermore, stretching can optionally further include in-air stretching the laminate at an elevated temperature (e.g., 95°C or higher) before stretching in the aqueous boric acid solution. Additionally, in one embodiment of the present invention, the laminate is preferably subjected to a drying shrinkage treatment in which the laminate is heated while being transported in the longitudinal direction, thereby shrinking the laminate by 2% or more in the width direction. Typically, the manufacturing method of this embodiment includes subjecting the laminate to an in-air auxiliary stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment, in this order. By introducing auxiliary stretching, it is possible to increase the crystallinity of PVA, even when PVA is coated on a thermoplastic resin, thereby achieving high optical properties. Furthermore, by simultaneously increasing the orientation of PVA in advance, problems such as a decrease in orientation or dissolution of PVA when immersed in water in the subsequent dyeing or stretching steps can be prevented, thereby achieving high optical properties. Furthermore, when the PVA-based resin layer is immersed in a liquid, the disordering of the orientation of polyvinyl alcohol molecules and the decrease in orientation can be suppressed compared to when the PVA-based resin layer does not contain a halide. This can improve the optical properties of a polarizer obtained through treatment steps in which the laminate is immersed in a liquid, such as a dyeing treatment and an underwater stretching treatment. Furthermore, the optical properties can be improved by shrinking the laminate in the width direction through drying shrinkage treatment.The obtained resin substrate / polarizer laminate may be used as is (i.e., the resin substrate may be used as a protective layer for the polarizer), or the resin substrate may be peeled off from the resin substrate / polarizer laminate and any appropriate protective layer depending on the purpose may be laminated on the peeled surface. Details of such a polarizer manufacturing method are described in, for example, JP 2012-73580 A and Japanese Patent No. 6470455 A. The entire disclosures of these publications are incorporated herein by reference.

[0063] The dyeing with iodine is carried out, for example, by immersing the PVA film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be carried out after the dyeing treatment or while dyeing. Alternatively, the PVA film may be stretched and then dyed. If necessary, the PVA film may be subjected to a swelling treatment, a crosslinking treatment, a washing treatment, a drying treatment, or the like. For example, by immersing the PVA film in water and washing it before dyeing, it is possible to wash away dirt and antiblocking agents on the surface of the PVA film, and also to swell the PVA film, thereby preventing uneven dyeing.

[0064] The thickness of the polarizer 2 is, for example, 1 μm to 80 μm, preferably 1 μm to 15 μm, more preferably 1 μm to 12 μm, and even more preferably 3 μm to 12 μm. When the thickness of the polarizer is within this range, curling during heating can be well suppressed and good appearance durability during heating can be obtained.

[0065] The polarizer 2 typically exhibits absorptive dichroism at any wavelength between 380 nm and 780 nm. The single transmittance of the polarizer 2 is, for example, 41.5% to 46.0%, preferably 43.0% to 46.0%, and more preferably 44.5% to 46.0%. The degree of polarization of the polarizer 2 is preferably 97.0% or more, more preferably 99.0% or more, and even more preferably 99.9% or more.

[0066] D. External shape processing In one embodiment, the resin film described in the above items A and B, or a product containing the resin film described in the above item C, is processed to have a desired shape, thereby producing a processed film 3 (or a product containing the processed film 3) having the desired outer shape.

[0067] Any appropriate method can be used for the outer shape processing. Examples of outer shape processing include punching using a punching blade, cutting using a spindle, and laser processing. Of these outer shape processing methods, laser processing is preferred. Various conditions in the external processing can be adjusted arbitrarily and appropriately.

[0068] The outer shape of the processed film 3 (or a product including the processed film 3) is not particularly limited. Examples of such shapes include a rectangular shape and irregular shapes other than a rectangular shape. Examples of irregular shapes include polygons other than a square, circles, ellipses, and shapes with irregularly shaped portions.

[0069] 4, in one embodiment, the processed film 3 (or a product including the processed film 3) has a contoured portion 31. Examples of the contoured portion 31 include a recess recessed inward from the outer edge of the processed film 3, and a through-hole penetrating the processed film 3. In the illustrated example, the processed film 3 has recesses 31a as irregularly shaped portions. The shape of the recesses is not particularly limited, and examples thereof include a V-shape and a U-shape.

[0070] When a resin film (or a product containing a resin film) is contoured into an irregular shape, cracks extending perpendicular to the thickness direction are more likely to occur on the edge surfaces of the resin film than when the resin film (or a product containing a resin film) is contoured into a rectangular shape. On the other hand, in one embodiment, since the shear fracture strength of the resin film is 2.5 N or more, even when the resin film (or a product containing a resin film) is contoured into an irregular shape as described above, the occurrence of cracks extending perpendicular to the thickness direction on the edge surfaces of the processed film can be stably suppressed. [Example]

[0071] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The methods for measuring each property are as follows.

[0072] (1) Measurement of shear fracture strength of resin film The shear fracture strength of the resin films obtained in the examples and comparative examples was measured by the surface-interface cutting method (SAICAS method). The results are shown in Table 1. More specifically, samples were prepared by cutting the resin film into approximately 2 cm square pieces. The samples were then cut using a SAICAS DN-20 (manufactured by Daipla Wintes) at a horizontal speed of 5 μm / min and a vertical speed of 0.5 μm / min. The parallel load FH [kN] and vertical displacement d [m] were measured when the sample was cut obliquely. The cutting edge width was 1 mm, the rake angle of the cutting edge was 10°, and the cutting edge was made of single-crystal diamond. The shear fracture strength τ was then calculated from the parallel load FH [kN], cutting edge width W [m], and vertical displacement d [m] using the following formula: τ [N] =FH [kN] / (2 × Wd [m 2 ]×cotφ)

[0073] (2) Presence or absence of cracks in the resin film during deforming The resin films obtained in the examples and comparative examples were processed using a CO2 laser to obtain processed films with recesses as irregularly shaped portions. The edge surfaces of the processed films were then checked for the presence or absence of cracks extending in the direction perpendicular to the thickness direction (lateral direction). The results are shown in Table 1.

[0074] [Example 1] 81.98 parts by mass of isosorbide (ISB), 47.19 parts by mass of tricyclodecane dimethanol (TCDDM), 175.1 parts by mass of diphenyl carbonate (DPC), and 0.979 parts by mass of a 0.2% by mass aqueous solution of cesium carbonate as a catalyst were charged into a reaction vessel. Under a nitrogen atmosphere, the heating vessel temperature was heated to 150°C as the first step of the reaction, and the raw materials were dissolved (approximately 15 minutes) with stirring as necessary. Next, the pressure was increased from atmospheric pressure to 13.3 kPa, and the heating vessel temperature was raised to 190°C over 1 hour, while the generated phenol was withdrawn from the reaction vessel. After the entire reaction vessel was held at 190°C for 15 minutes, the pressure inside the reaction vessel was increased to 6.67 kPa, and the heating vessel temperature was raised to 230°C over 15 minutes as the second step, and the generated phenol was withdrawn from the reaction vessel. As the stirring torque of the mixer increased, the temperature was raised to 250°C in 8 minutes. Furthermore, the pressure inside the reactor was reduced to 0.200 kPa or less to remove the generated phenol. After reaching the predetermined stirring torque, the reaction was terminated, and the resulting reaction product was extruded into water to obtain PC resin pellets. The resulting PC resin was vacuum-dried at 100°C for 12 hours. A 40 μm-thick PC resin film was then produced using a film-forming device equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder temperature setting: 250°C), a T-die (width: 1700 mm, temperature setting: 250°C), a cast roll (temperature setting: 60°C), and a winder. The in-plane retardation (Re(550)) of the PC resin film was 3.0 nm.

[0075] [Comparative Example 1] An acrylic resin film (manufactured by Kaneka Corporation, product name "HTX-Z") having a thickness of 40 μm was prepared.

[0076] [Table 1]

[0077] [evaluation] As is clear from Table 1, when the shear fracture strength of the resin film is 2.5 N or more, it is possible to prevent cracks extending laterally from occurring on the end faces of the resin film during shaping. [Industrial Applicability]

[0078] The resin film of the present invention can be applied to various industrial products, and can be particularly suitably used for optical members such as decorative films and polarizing plates. [Explanation of symbols]

[0079] 1 Resin film 2 polarizers 3. Processed film

Claims

1. The shear breaking strength is 2.5N or more, The thickness is 40 μm or more, The in-plane retardation Re(550) is 3 nm or less, It is made of polycarbonate resin, A resin film, wherein the polycarbonate resin contains a structural unit derived from a dihydroxy compound (A) represented by the following formula (2), a structural unit derived from an alicyclic dihydroxy compound (B) represented by the following general formula (I), and a carbonate group connecting them: 【Chemistry 2】 HOCH ２ -R １ -CH ２ OH(I) (In formula (I), R １ represents a cycloalkylene group having 4 to 20 carbon atoms.

2. A method for producing a processed film, comprising processing the resin film according to claim 1 into an outer shape.

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