JP2011013378A - Film - Google Patents

Abstract

A film having a small in-plane retardation and excellent impact resistance is provided.
A film having an in-plane retardation of 1 nm or less has a total of 3 or more aromatic vinyl compound hydride blocks and diene compound hydride blocks, and the content of aromatic vinyl compound hydride block is 82% by weight to 90% by weight, diene compound hydride block content is 10% by weight to 18% by weight, and at least one end of the polymer chain is composed of an aromatic vinyl compound hydride block. This is realized by providing a layer including coalescence.
[Selection figure] None

Description

  The present invention relates to a film, and more particularly to a film suitable for use as a polarizing plate protective film.

A display device such as a liquid crystal display device is provided with various optical elements such as a polarizing plate and a retardation plate. Some of these optical elements are made of a film (see Patent Documents 1 to 5).
In addition, techniques as described in Patent Documents 6 to 8 are also known.

JP 2000-169521 A JP 2001-48924 A JP 2002-105151 A JP 2003-114329 A JP 2002-53631 A JP-A-1-317728 JP 2002-47311 A JP 2002-60447 A

By the way, a polarizing plate protective film is usually provided in a polarizing plate among optical elements. The polarizing plate protective film is required to have both a small in-plane retardation (also referred to as retardation) and excellent impact resistance.
However, in the conventional technology, there is a tendency that a phase difference is easily developed in the film manufacturing process, and it is possible to realize a film that achieves both a small in-plane retardation and excellent impact resistance. It was difficult.

  The present invention has been made in view of the above, and an object thereof is to provide a film having a small in-plane phase difference and excellent impact resistance.

In order to solve the above-described problems and achieve the object, the present inventors have intensively studied, and as a result, the aromatic vinyl compound hydride block and the diene compound hydride block include a predetermined number of blocks at a predetermined weight ratio, The inventors have found that a layer containing a block copolymer in which one end of a polymer chain is an aromatic vinyl compound hydride block has a small in-plane retardation Re and excellent impact resistance, thereby completing the present invention.
That is, the gist of the present invention is the following [1] to [5].

[1] A film having a layer A containing a vinyl alicyclic hydrocarbon polymer, wherein the vinyl alicyclic hydrocarbon polymer comprises a total of 3 aromatic vinyl compound hydride blocks and diene compound hydride blocks. The aromatic vinyl compound hydride block content is 82 wt% to 90 wt%, the diene compound hydride block content is 10 wt% to 18 wt%, and at least one end of the polymer chain A film comprising an aromatic vinyl compound hydride block and having an in-plane retardation of 1 nm or less.
[2] It further includes a layer B laminated on the layer A, and the layer B is a layer containing the vinyl alicyclic hydrocarbon polymer and fine particles, and the number average particle diameter of the fine particles is 0.01 μm to [1] The film according to [1], which is 1.0 μm, and the weight ratio of fine particles to the vinyl alicyclic hydrocarbon polymer in the layer B is 0.01% to 5.00%.
[3] Layer A containing a vinyl alicyclic hydrocarbon polymer, and at least one material selected from the group consisting of polyester, polycarbonate, polypropylene, hydrogenated norbornene polymer, and methacrylate polymer The vinyl alicyclic hydrocarbon polymer has a total of 3 or more blocks of aromatic vinyl compound hydride block and diene compound hydride block, and the aromatic vinyl compound hydrogen. The content of the halide block is 82% by weight to 90% by weight, the content of the diene compound hydride block is 10% by weight to 18% by weight, and at least one end of the polymer chain is composed of an aromatic vinyl compound hydride block, Obtained by coextrusion of a resin containing the vinyl alicyclic hydrocarbon polymer and a resin containing the material, Irumu.
[4] The film according to any one of [1] to [3], wherein the layer A contains an ultraviolet absorber.
[5] The film according to any one of [1] to [4], which is a stretched film.

  The film of the present invention has a small in-plane retardation and excellent impact resistance.

  Hereinafter, the present invention will be described in detail with reference to examples and embodiments, but the present invention is not limited to the examples and embodiments listed below, and can be arbitrarily changed without departing from the gist of the present invention. Can be implemented. In the following description, reference sign “A” for layer A, reference sign “B” for layer B, reference sign “C” for layer C, reference sign “(M1)” for methacrylate ester (M1), and acrylic ester (M2). ), “(M3)” of the compound (M3) having a vinyl group, “(M4)” of the methacrylate (M4), and the compound (M5) having a vinyl group. The symbol “(M5)” is a symbol assigned to distinguish the component with the symbol from other components, and has no meaning other than the distinction between the components.

[1. Composition of film]
[1-1. Vinyl alicyclic hydrocarbon polymer]
(1) Structure of vinyl alicyclic hydrocarbon polymer The film of the present invention includes at least a layer A containing a vinyl alicyclic hydrocarbon polymer. The vinyl alicyclic hydrocarbon polymer contained in the layer A is a block copolymer having at least an aromatic vinyl compound hydride block and a diene compound hydride block.

  Aromatic vinyl compound hydride block refers to a block composed of a repeating unit having the same structure as the repeating unit of a polymer obtained by polymerizing an aromatic vinyl compound and then hydrogenating its unsaturated bond, For example, it refers to a block composed of repeating units represented by the following structural formula (1). However, the aromatic vinyl compound hydride block may be produced by any method as long as the structure is as described above.

In the structural formula (1), R ^c represents an alicyclic hydrocarbon group. Examples of R ^c include cyclohexyl groups such as cyclohexyl group; decahydronaphthyl groups and the like.

In the structural formula (1), R ¹ , R ² and R ³ are each independently a hydrogen atom, a chain hydrocarbon group, a halogen atom, an alkoxy group, a hydroxyl group, an ester group, a cyano group, an amide group or an imide group. Represents a chain hydrocarbon group substituted with a silyl group or a polar group (halogen atom, alkoxy group, hydroxyl group, ester group, cyano group, amide group, imide group, or silyl group). Among them, R ¹ , R ² and R ³ are preferably a hydrogen atom and a chain hydrocarbon group having 1 to 6 carbon atoms from the viewpoints of heat resistance, low birefringence, mechanical strength and the like. The chain hydrocarbon group is preferably a saturated hydrocarbon group, and more preferably an alkyl group.

  The molecular weight of the aromatic vinyl compound hydride block is usually 1000 or more, preferably 2000 or more, more preferably 3000 or more, and usually 100,000 or less, preferably 90000 or less, more preferably 80000 or less. The advantage that the elastic modulus of the film is improved by the molecular weight of the aromatic vinyl compound hydride block being not less than the lower limit of the above range, and the impact resistance of the film is improved by being not more than the upper limit. Is obtained. Moreover, when there are a plurality of aromatic vinyl compound hydride blocks, the molecular weight of each block can be set to a value within the above range. In this case, the molecular weight of each block may be the same or different.

  Examples of the repeating unit of the aromatic vinyl compound hydride block include the following examples. In addition, what has a stereoisomer in the following examples can use any of the stereoisomers. Moreover, the repeating unit of an aromatic vinyl compound hydride block may use only 1 type, and may use it combining 2 or more types by arbitrary ratios. Further, only one type of aromatic vinyl compound hydride block may be used, or two or more types may be used in combination at any ratio.

  The content of the aromatic vinyl compound hydride block contained in the vinyl alicyclic hydrocarbon polymer is 82% by weight or more, preferably 84% by weight or more, 90% by weight or less, preferably 88% by weight or less. is there. When the content of the aromatic vinyl compound hydride block is out of this range, the phase difference Re in the plane direction tends to increase in the layer A.

  In the polymer chain of the vinyl alicyclic hydrocarbon polymer, at least one end, preferably a plurality of ends, of the ends of the polymer chain is composed of an aromatic vinyl compound hydride block. Thereby, impact resistance can be improved. In addition, it can confirm by NMR method that the terminal of a polymer chain consists of an aromatic vinyl compound hydride block.

  The diene compound hydride block has the same structure as the repeating unit of the polymer obtained by polymerizing the diene compound and then hydrogenating the unsaturated bond if the polymer obtained has an unsaturated bond. The block which consists of a repeating unit which has. Especially, it is preferable that a diene compound hydride block is a block which consists of a repeating unit which has a structure similar to the repeating unit of the polymer obtained by polymerizing a conjugated diene compound and hydrogenating the unsaturated bond. When the example is given, the block which consists of a repeating unit represented, for example by following Structural formula (2) or Structural formula (3) is mentioned. However, the diene compound hydride block may be produced by any method as long as the structure is as described above.

In Structural Formula (2), R ^{4 to} R ⁹ are each independently a hydrogen atom, a chain hydrocarbon group, a halogen atom, an alkoxy group, a hydroxyl group, an ester group, a cyano group, an amide group, an imide group, or a silyl group. Or a chain hydrocarbon group substituted with a polar group (halogen atom, alkoxy group, hydroxyl group, ester group, cyano group, amide group, imide group, or silyl group). Among them, R ^{4 to} R ⁹ are preferably a hydrogen atom and a chain hydrocarbon group having 1 to 6 carbon atoms from the viewpoints of heat resistance, low birefringence, mechanical strength, and the like. The chain hydrocarbon group is preferably a saturated hydrocarbon group, and more preferably an alkyl group.

In the structural formula (3), R ^{10 to} R ¹⁵ each independently represent a hydrogen atom, a chain hydrocarbon group, a halogen atom, an alkoxy group, a hydroxyl group, an ester group, a cyano group, an amide group, an imide group, or a silyl group. Or a chain hydrocarbon group substituted with a polar group (halogen atom, alkoxy group, hydroxyl group, ester group, cyano group, amide group, imide group, or silyl group). Among them, R ^{10 to} R ¹⁵ are preferably a hydrogen atom and a chain hydrocarbon group having 1 to 6 carbon atoms from the viewpoints of heat resistance, low birefringence, mechanical strength, and the like. The chain hydrocarbon group is preferably a saturated hydrocarbon group, and more preferably an alkyl group.

  The molecular weight of the diene compound hydride block is usually 500 or more, preferably 1000 or more, more preferably 2000 or more, and usually 50000 or less, preferably 30000 or less, more preferably 20000 or less. When the molecular weight of the diene compound hydride block is not less than the lower limit of the above range, an advantage that the impact resistance is improved is obtained, and when it is not more than the upper limit, an advantage that the elastic modulus is improved is obtained. Moreover, when there are a plurality of diene compound hydride blocks, the molecular weight of each block can be set to a value within the above range. In this case, the molecular weight of each block may be the same or different.

  Examples of the repeating unit of the diene compound hydride block include the following examples. In addition, what has a stereoisomer in the following examples can use any of the stereoisomers. Moreover, only one type of repeating unit of the diene compound hydride block may be used, or two or more types may be used in combination at any ratio. Furthermore, only one type of diene compound hydride block may be used, or two or more types may be used in combination at any ratio.

  The content of the diene compound hydride block contained in the vinyl alicyclic hydrocarbon polymer is 10% by weight or more, preferably 12% by weight or more, and 18% by weight or less, preferably 16% by weight or less. When the content of the diene compound hydride block is outside this range, the phase difference Re in the plane direction tends to increase in the layer A.

  The vinyl alicyclic hydrocarbon polymer has a total of 3 or more blocks of aromatic vinyl compound hydride blocks and diene compound hydride blocks. By having a total of three or more blocks of aromatic vinyl compound hydride blocks and diene compound hydride blocks, it becomes possible to improve impact resistance. In addition, the heat resistance of the layer A can usually be increased. On the other hand, the upper limit is arbitrary as long as the effects of the present invention are not significantly impaired, but it is preferably 5 blocks or less, more preferably 4 blocks or less. This is because if the number of blocks is too large, impact resistance tends to decrease.

  The vinyl alicyclic hydrocarbon polymer may have other blocks in addition to the aromatic vinyl compound hydride block and diene compound hydride block as long as the effects of the present invention are not significantly impaired. However, it is preferable that the number of other blocks is small from the viewpoint of exhibiting the effects of the present invention more remarkably. The specific content of other blocks that the vinyl alicyclic hydrocarbon polymer may contain is not uniform depending on the use of the film, etc., but is usually 10% by weight or less, preferably 5% by weight or less, more preferably Is 3% by weight or less, and it is particularly preferable not to contain.

  The weight average molecular weight Mw of the vinyl alicyclic hydrocarbon polymer is usually 50,000 or more, preferably 55,000 or more, more preferably 60,000 or more, and usually 100,000 or less, preferably 90,000 or less. More preferably, it is 80,000 or less. When the weight average molecular weight Mw is not less than the lower limit of the above range, the impact resistance of the film can be improved, and when it is not more than the upper limit, the viscosity of the polymer can be lowered and the moldability can be improved.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the vinyl alicyclic hydrocarbon polymer is usually 2 or less, preferably 1.5 or less, more preferably 1.2 or less. Thereby, a polymer viscosity can be lowered | hung and a moldability can be improved.

The glass transition temperature Tg _A of the vinyl alicyclic hydrocarbon polymer is usually 110 ° C. or higher, preferably 115 ° C. or higher, more preferably 120 ° C. or higher, and usually 150 ° C. or lower, preferably 148 ° C. or lower, more preferably. It is 145 degrees C or less. When the glass transition temperature of the vinyl alicyclic hydrocarbon polymer is not less than the lower limit of the above range, an advantage that the heat resistance of the film is improved is obtained, and when it is not more than the upper limit, the processing temperature is lowered to increase the moldability. The advantage is obtained. The glass transition temperature Tg _A of the vinyl alicyclic hydrocarbon polymer, when a plurality of glass transition temperature is observed, it is possible to adopt the numerical value of the higher.

  The tensile elastic modulus of the vinyl alicyclic hydrocarbon polymer is usually 1,500 MPa or more, preferably 1,600 MPa or more, and usually 2,500 MPa or less, preferably 2,200 MPa or less. The advantage that the elasticity of the film is obtained when the tensile modulus of the vinyl alicyclic hydrocarbon polymer is not less than the lower limit of the above range is obtained, and the impact resistance of the film is improved by being less than the upper limit. The advantage is that

(2) Production method of vinyl alicyclic hydrocarbon polymer Although there is no limitation on the production method of vinyl alicyclic hydrocarbon polymer, it corresponds to, for example, each of aromatic vinyl compound hydride block and diene compound hydride block. A monomer is prepared, this is block-polymerized to obtain a polymer, and the resulting polymer is hydrogenated.

Examples of monomers corresponding to the aromatic vinyl compound hydride block include styrene, α-methyl styrene, α-ethyl styrene, α-propyl styrene, α-isopropyl styrene, α-t-butyl styrene, 2- Methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, monochlorostyrene, dichlorostyrene Styrenes such as monofluorostyrene and 4-phenylstyrene; vinylcyclohexanes such as vinylcyclohexane and 3-methylisopropenylcyclohexane; 4-vinylcyclohexene, 4-isopropenylcyclohexene, 1-methyl-4-vinylcyclohexene, 1 -Methyl-4-isop Vinylcyclohexenes such as lopenylcyclohexene, 2-methyl-4-vinylcyclohexene, 2-methyl-4-isopropenylcyclohexene; and the like.
In addition, the monomer corresponding to an aromatic vinyl compound hydride block may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

On the other hand, examples of monomers corresponding to diene compound hydride blocks include chains such as butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene. And conjugated dienes.
In addition, the monomer corresponding to a diene compound hydride block may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

In general, anionic polymerization can be employed for the polymerization.
The polymerization may be performed by any of bulk polymerization and solution polymerization. Among these, solution polymerization is preferable in order to continuously perform the polymerization reaction and the hydrogenation reaction.

Examples of the reaction solvent for polymerization include aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane, and isooctane; cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, decalin, and the like. And alicyclic hydrocarbons; aromatic hydrocarbons such as benzene and toluene. Of these, the use of aliphatic hydrocarbons and alicyclic hydrocarbons is preferable because they can be used as they are as an inert solvent for the hydrogenation reaction.
In addition, a reaction solvent may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
The reaction solvent is usually used at a ratio of 200 to 10,000 parts by weight with respect to 100 parts by weight of the total monomers.

  In the polymerization, a polymerization initiator is usually used. Examples of the polymerization initiator include monoorganolithium such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, and phenyllithium; dilithiomethane, 1,4-diobtan, 1,4-dilithio-2-ethyl And polyfunctional organolithium compounds such as cyclohexane. In addition, a polymerization initiator may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  When polymerizing each polymer block, a polymerization accelerator, a randomizer, or the like can be used in order to prevent an excessively long chain of one component in each block. For example, when the polymerization is performed by anionic polymerization, a Lewis base compound or the like can be used as a randomizer. Specific examples of Lewis base compounds include ether compounds such as dimethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, tetrahydrofuran, diphenyl ether, ethylene glycol diethyl ether, ethylene glycol methyl phenyl ether; tetramethylethylenediamine, trimethylamine, triethylamine, pyridine, etc. Tertiary amine compounds; alkali metal alkoxide compounds such as potassium-t-amyl oxide and potassium-t-butyl oxide; phosphine compounds such as triphenylphosphine. In addition, these may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.

  The polymerization temperature is not limited as long as the polymerization proceeds, but is usually 0 ° C. or higher, preferably 20 ° C. or higher, and is usually 200 ° C. or lower, preferably 100 ° C. or lower, more preferably 80 ° C. or lower.

  After the polymerization, the polymer can be recovered by a known method such as a steam stripping method, a direct solvent removal method, or an alcohol coagulation method. Further, when a solvent inert to the hydrogenation reaction is used as the reaction solvent during the polymerization, the polymer can be used as it is without recovering the polymer from the polymerization solution.

  There is no restriction | limiting in the hydrogenation method of a polymer, For example, what is necessary is just to perform using a suitable hydrogenation catalyst. For example, a hydrogenation catalyst containing at least one metal selected from the group consisting of nickel, cobalt, iron, titanium, rhodium, palladium, platinum, ruthenium, and rhenium may be used in an organic solvent. As the hydrogenation catalyst, either a heterogeneous catalyst or a homogeneous catalyst can be used. Moreover, a hydrogenation catalyst may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The heterogeneous catalyst may be used as it is as a metal or a metal compound, or may be used by being supported on an appropriate carrier. Examples of the carrier include activated carbon, silica, alumina, calcium carbide, titania, magnesia, zirconia, diatomaceous earth, silicon carbide and the like. The amount of the catalyst supported on the carrier is usually 0.01% by weight or more, preferably 0.05% by weight or more, and usually 80% by weight or less, preferably 60% by weight or less.
The homogeneous catalyst is, for example, a catalyst in which a compound of nickel, cobalt, titanium or iron and an organometallic compound (for example, organoaluminum compound, organolithium compound) is combined; organometallic such as rhodium, palladium, platinum, ruthenium and rhenium Complex catalyst; and the like. Examples of the nickel, cobalt, titanium, or iron compound include acetylacetone salts, naphthenic acid salts, cyclopentadienyl compounds, cyclopentadienyl dichloro compounds of various metals, and the like. Examples of the organic aluminum compound include alkylaluminums such as triethylaluminum and triisobutylaluminum; aluminum halides such as diethylaluminum chloride and ethylaluminum dichloride; alkylaluminum hydrides such as diisobutylaluminum hydride; and the like.
Examples of the organometallic complex catalyst include metal complexes such as γ-dichloro-π-benzene complex, dichloro-tris (triphenylphosphine) complex, hydrido-chloro-triphenylphosphine) complex of each of the above metals. .
The amount of the hydrogenation catalyst used is usually 0.01 parts by weight or more, preferably 0.05 parts by weight or more, more preferably 0.1 parts by weight or more, and usually 100 parts by weight with respect to 100 parts by weight of the polymer. Hereinafter, it is preferably 50 parts by weight or less, more preferably 30 parts by weight or less.

The reaction temperature during the hydrogenation reaction is usually 10 ° C. to 250 ° C., but is preferably 50 ° C. or more, more preferably, because the hydrogenation rate can be increased and the polymer chain scission reaction can be reduced. It is 80 degreeC or more, Preferably it is 200 degrees C or less, More preferably, it is 180 degrees C or less. Further, the pressure during the reaction is usually 0.1 MPa to 30 MPa, but in addition to the above reasons, from the viewpoint of operability, it is preferably 1 MPa or more, more preferably 2 MPa or more, preferably 20 MPa or less, more preferably 10 MPa or less.
The hydrogenation rate is usually 90% or more, preferably 95% or more, more preferably 97% or more. By increasing the hydrogenation rate, the low birefringence and thermal stability of the vinyl alicyclic hydrocarbon polymer can be enhanced. The hydrogenation rate can be measured by ¹ H-NMR.

[1-2. Layer A]
(1) Composition of Layer A Layer A provided in the film of the present invention is a layer containing at least a vinyl alicyclic hydrocarbon polymer. Layer A may contain only one type of vinyl alicyclic hydrocarbon polymer, or may contain two or more types in combination at any ratio.

  Further, the layer A may contain an ultraviolet absorber. Thereby, the film of this invention can acquire the tolerance with respect to an ultraviolet-ray. For this reason, for example, when using the film of the present invention as an optical film such as a polarizing plate protective film, it is possible to protect the film of the present invention and the protection target such as the polarizing plate protected by this film from deterioration due to ultraviolet rays. Become.

  As the UV absorber, for example, benzophenone UV absorbers, benzotriazole UV absorbers, triazine UV absorbers, acrylonitrile UV absorbers, benzoate UV absorbers, etc. can be used. Absorbers, triazine ultraviolet absorbers, benzophenone ultraviolet absorbers, and benzoate ultraviolet absorbers are preferred. Of these, 2,2′-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2 -(2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2,4-di-tert-butyl-6- (5-chlorobenzotriazol-2-yl) Phenol; 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone as benzophenone UV absorber; 2- ( 4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol; benzoate ultraviolet The absorbent, 2,4-di -tert- butyl-4-hydroxybenzoate; and the like are suitably used. Among these, 2,2'-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol) is particularly preferable. In addition, a ultraviolet absorber may be used by 1 type and may be used combining two or more types by arbitrary ratios.

  Examples of the method for containing the ultraviolet absorber in the layer A include, for example, a method in which the ultraviolet absorber is previously mixed with a vinyl alicyclic hydrocarbon polymer; a method in which a master batch containing the ultraviolet absorber in a high concentration is used; Examples include a method of directly supplying at the time of molding.

  However, the concentration of the ultraviolet absorber in the layer A is preferably 0.5% by weight or more, more preferably 1.0% by weight or more, and preferably 8.0% by weight or less. By keeping the concentration of the ultraviolet absorber within the above range, it is possible to efficiently block ultraviolet rays without deteriorating the color tone of the film of the present invention. When the concentration of the ultraviolet absorber is less than the lower limit of the above range, the light transmittance at wavelengths of 370 nm and 380 nm increases, and the degree of polarization of the polarizing plate may decrease when the film of the present invention is used as a polarizing plate protective film. There is sex. On the other hand, if the content of the ultraviolet absorber exceeds the upper limit of the above range, the light transmittance on the short wavelength side may be reduced, and the yellowness of the film may be too strong.

  Moreover, it is preferable that the dispersion | variation in the density | concentration of the ultraviolet absorber in the layer A is less than +/- 0.1 weight% on the whole surface. Thereby, there is no uneven color tone of the initial film, and the deterioration due to ultraviolet rays after long-term use occurs uniformly, and the uneven color tone hardly occurs when the film of the present invention is mounted on a liquid crystal display device. If the variation in the concentration of the UV absorber in the layer A exceeds ± 0.1% by weight over the entire surface, uneven color tone can be clearly recognized, which may result in poor color tone. In addition, after long-term use, deterioration due to ultraviolet rays becomes non-uniform, and color tone defects may become more prominent.

In addition, the dispersion | variation in the density | concentration of the ultraviolet absorber in the layer A is measured in the following procedures. First, the ultraviolet transmittance of the film is measured with a spectrophotometer. Next, the thickness of the film is measured with a contact-type thickness meter. Next, if the film has a layer other than layer A, the cross section of the measurement part is observed with an optical microscope, the ratio of the thickness of layer A to a layer other than layer A is determined, and the thickness of layer A is determined. And the density | concentration of a ultraviolet absorber is computed from following numerical formula [1] from a ultraviolet-ray transmittance and the thickness of the layer A. FIG.
Formula [1]: C = −log (0.01T) / K / L
In Formula [1], C is the concentration (% by weight) of the UV absorber, T is the light transmittance (%), K is the extinction coefficient (−), and L is the film thickness (μm).
The concentration of the UV absorber is measured at regular intervals in the longitudinal and lateral directions of the film, and an arithmetic average value of these measured values is taken as an average concentration C _ave . Then, with the maximum value of the measured density C being C _max and the minimum value being C _min , the density variation is calculated from the following equation.
Concentration variation (%) = (C _min −C _ave ) / C _ave × 100, or
Concentration variation (%) = (C _max −C _ave ) / C _ave × 100
Here, when the absolute values of C _min -C _ave and C _max -C _ave are different, the larger absolute value is adopted.

  As a method for making the variation in the concentration of the ultraviolet absorber in the layer A ± 0.1% by weight over the entire surface, (i) mixing the dried vinyl alicyclic hydrocarbon polymer and the ultraviolet absorber, Next, the mixture is charged into a hopper connected to an extruder, and supplied to a single screw extruder and melt extruded; (2) a vinyl alicyclic hydrocarbon polymer is charged into a hopper with a dryer; A method in which an ultraviolet absorber is introduced from another inlet, and the vinyl alicyclic hydrocarbon polymer and the ultraviolet absorber are fed to a twin-screw extruder while being metered with a feeder and melt extruded.

  Further, the layer A may be a layer containing components other than the vinyl alicyclic hydrocarbon polymer and the ultraviolet absorber as long as the effects of the present invention are not significantly impaired. Examples of such components include: inorganic fine particles; stabilizers such as antioxidants, heat stabilizers and near infrared absorbers; resin modifiers such as lubricants and plasticizers; colorants such as dyes and pigments; Examples include inhibitors. One of these other components may be included, and two or more may be included in any ratio and combination. However, the amount of other components is preferably small from the viewpoint of remarkably exhibiting the effects of the present invention. The specific amount of the other components depends on the use of the film of the present invention and the thickness of the layer A, but is preferably 10 parts by weight or less with respect to 100 parts by weight of the vinyl alicyclic hydrocarbon polymer, 5 parts by weight or less is more preferable, and 3 parts by weight or less is still more preferable. Among these, it is particularly preferable that other components are not included.

(2) Dimensions of Layer A The thickness of the layer A is usually 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and usually 35 μm or less, preferably 30 μm or less, more preferably 25 μm or less. When the thickness of the layer A is not less than the lower limit of the above range, there is an advantage that handling properties such as prevention of damage to the polarizing plate are improved when used as a polarizing plate protective film. There is an advantage that you can.

  The variation in the thickness of the layer A is preferably within ± 1 μm over the entire surface. When the variation in the thickness of the layer A is within ± 1 μm on the entire surface, the variation in the color tone of the film of the present invention is reduced. In addition, since the color tone change after long-term use is uniform, color tone unevenness after long-term use hardly occurs.

In addition, when the film of the present invention is a laminated film having layers other than the layer A, the thickness of the layer A is measured using a commercially available contact thickness gauge, and the thickness measurement portion is measured. After cutting, the cross section is observed with an optical microscope, the thickness ratio between the layer A and the other layer is obtained, and the thickness of the layer A is calculated from the ratio.
The thickness of the layer A is measured at regular intervals in the transverse and longitudinal directions of the film, the arithmetic average value of the measured values is set as the reference thickness T _ave, and the maximum value of the measured thickness T is T _max The thickness variation is calculated from the following equation, with the minimum value being T _min .
Thickness variation (μm) = T _min −T _ave or Thickness variation (μm) = T _max −T _ave
Here, when the absolute values of T _min −T _ave and T _max −T _ave are different, the larger absolute value is adopted.

(3) Physical properties of layer A The in-plane retardation Re of layer A is usually 1 nm or less, preferably 0.8 nm or less, more preferably 0.5 nm or less, and the lower limit is ideally 0 nm. Since the in-plane retardation Re of the layer A is so small, the film of the present invention can be suitably used as a protective film for optical elements such as polarizing plates.
Further, the thickness direction retardation Rth of the layer A is usually 1 nm or less, preferably 0.8 nm or less, more preferably 0.5 nm or less, and the lower limit is ideally 0 nm.
The reason why the phase differences Re and Rth of the layer A can be reduced in this way is not clear, but according to the study by the inventor, it is assumed that the reason is as follows. That is, in the vinyl alicyclic hydrocarbon polymer, the aromatic vinyl compound hydride has a negative birefringence, and the diene compound hydride has a positive birefringence. It is presumed that the positive and negative phase differences expressed in the unit of the above are offset, and the expression of the phase difference of the entire layer A is suppressed.
The in-plane retardation Re of the layer A is expressed by Re = | nx−ny | × d, where the main refractive index in the plane of the layer A is nx and ny, and the thickness of the layer A is d (nm). Desired. Further, the retardation Rth in the thickness direction is such that the in-plane main refractive index of the entire layer A is nx and ny, the refractive index in the thickness direction is nz, and the thickness of the layer A is d (nm). Rth = [{(nx + ny) / 2} −nz] × d. These phase differences Re and Rth can be measured using, for example, a commercially available automatic birefringence meter. The phase differences Re and Rth are evaluated for light having a wavelength of 590 nm.

  The layer A is usually a transparent layer and transmits visible light well. Although the specific light transmittance is not uniform depending on the use of the film of the present invention, the light transmittance at a wavelength of 420 to 780 nm is usually 85% or more, preferably 88% or more. When the layer A has such a high light transmittance at a wavelength of 420 to 780 nm, when the film of the present invention is mounted on a display device such as a liquid crystal display device, it is possible to suppress a decrease in luminance particularly during long-term use.

When layer A contains an ultraviolet absorber, the light transmittance at a wavelength of 250 nm to 370 nm of layer A is preferably 0.1% or less. The lower limit is ideally 0%. Since the layer A does not transmit ultraviolet rays having a wavelength of 250 nm to 370 nm as described above, the film of the present invention can be used as a good protective film for optical elements, and for example, yellowing of a polarizing film or the like can be prevented over a long period of time.
The light transmittance can be measured using a spectrophotometer according to JIS K0115.

  Layer A is excellent in impact resistance. The reason for such excellent impact resistance is not clear, but according to the study of the present inventor, it is presumed that the reason is as follows. That is, in the vinyl alicyclic hydrocarbon polymer, the aromatic vinyl compound hydride block and the diene compound hydride block are phase-separated, and the diene compound hydride block is between the phase domains of the aromatic vinyl compound hydride block. It is inferred that the structure has a structure in which the phase domains of each other are connected, and in such a domain structure, the diene compound hydride block functions like a buffer material, so it is assumed that the impact resistance is improved. Is done.

  Layer A is usually excellent in heat resistance. This is because the vinyl alicyclic hydrocarbon polymer is excellent in heat resistance, so that the layer A containing the polymer also has high heat resistance. The specific degree of heat resistance can be set according to the composition ratio of the aromatic vinyl compound block and the diene compound hydride block of the vinyl alicyclic hydrocarbon polymer, the molecular weight, the thickness of the layer A, etc. What is necessary is just to adjust suitably according to the use of.

[1-3. Layer structure]
The film of the present invention can have any layer structure as long as it has at least one layer A. Therefore, the film of the present invention may be, for example, a single-layer film having only one layer A, or a laminated film having two or more layers A. Alternatively, a film having a laminated structure including one layer or two or more layers may be used. Examples of the layer other than the layer A that the film of the present invention may have include, for example, a hard coat layer such as a mat layer and an impact-resistant polymethacrylate resin layer that improve the slipperiness of the film, an antireflection layer, and an antifouling layer Is mentioned.

However, in any layer configuration, the film itself of the present invention is excellent in the phase difference, light transmittance, impact resistance, heat resistance, etc. of the layer A described in the physical properties of the layer A. It is preferable to have physical properties similar to the physical properties. Therefore, for example, with respect to the in-plane retardation Re, the in-plane retardation Re of the film is preferably 1 nm or less for any film having a layer structure. In addition, when peeling a peeling layer (for example, layer C) from a film at the time of its use, as in the second example of the layer configuration described later, the physical properties of the layer remaining after peeling the peeling layer from the film are: It is preferable to have the same physical properties as described in the physical property section A, and the film before peeling may not have the physical properties.
The specific layer configuration of the film of the present invention can be set according to the use of the film of the present invention, etc. Among them, the following two examples are preferable as examples of the layer configuration.

(1) First Example of Layer Structure First, a first example of the layer structure of the film of the present invention will be described. The film according to the first example is a laminated film including at least the layer B in addition to the layer A.
Here, the layer B is a layer containing at least the above-described vinyl alicyclic hydrocarbon polymer and fine particles. Since the layer B includes the vinyl alicyclic hydrocarbon polymer, the film according to the first example can reduce the retardation Re and can improve the impact resistance. In general, since the layer B contains a vinyl alicyclic hydrocarbon polymer, the affinity with the layer A is increased, so that the adhesive strength between the layer A and the layer B can be increased. Furthermore, since the layer B contains fine particles, the surface of the layer B has good slipperiness, so that the handleability of the film can be improved.

  The vinyl alicyclic hydrocarbon polymer contained in layer B is the same as the vinyl alicyclic hydrocarbon polymer contained in layer A.

  The fine particles contained in the layer B may be inorganic particles, organic particles, or composite particles combining an inorganic material and an organic material. Of these, inorganic particles are preferable, and metal oxide fine particles are more preferable. Specific examples thereof include titanium oxide, zirconium oxide, zinc oxide, copper oxide, aluminum oxide, cerium oxide, yttrium oxide, silicon oxide, tin oxide, iron oxide, magnesium oxide, and manganese oxide. Among these, titanium oxide-silicon oxide based metal oxides are particularly preferable because the refractive index can be easily adjusted. These fine particles can be produced, for example, using the technique described in JP-A-7-2520. Note that one kind of fine particles may be used, or two or more kinds may be used in combination at an arbitrary ratio.

The average particle size of the fine particles contained in the layer B is usually 0.01 μm or more, preferably 0.03 μm or more, more preferably 0.05 μm or more, and usually 1.0 μm or less, preferably 0.5 μm or less, more preferably Is 0.3 μm or less. By making the average particle diameter of the fine particles equal to or more than the lower limit of the above range, it becomes possible to improve the slipperiness of the film. Moreover, the haze of a film can be suppressed by making the average particle diameter of fine particles below the upper limit of the said range.
The average particle diameter of the fine particles can be measured by measuring 200 or more particle diameters from a photograph taken with a transmission electron microscope and calculating the average value.

  The refractive index of the fine particles is usually 1.20 or more, preferably 1.30 or more, more preferably 1.40 or more, particularly preferably 1.43 or more, and usually 1.60 or less, preferably 1.57 or less, More preferably, it is 1.55 or less. By keeping the refractive index of the fine particles within this range, it is possible to avoid a decrease in transparency of the film due to the fine particles.

  In layer B, the weight ratio of the fine particles to the vinyl alicyclic hydrocarbon polymer is usually 0.01% or more, preferably 0.03% or more, more preferably 0.05% or more, and usually 5.00%. Hereinafter, it is preferably 4.00% or less, more preferably 3.00% or less. By making the weight ratio of the fine particles equal to or higher than the lower limit of the range, it becomes possible to improve the slipperiness of the film. Further, by setting the weight ratio of the fine particles to be equal to or less than the upper limit of the above range, it is possible to prevent white powder due to dropping off of fine particles from being generated on the surface of the film, resulting in damage or a decrease in the strength of the layer B.

  The layer B may be a layer containing components other than the vinyl alicyclic hydrocarbon polymer and the fine particles as long as the effects of the present invention are not significantly impaired. However, from the viewpoint of remarkably exerting the effects of the present invention, it is preferable that the amount of components other than the vinyl alicyclic hydrocarbon polymer and the fine particles is small. The specific amount of components other than the vinyl alicyclic hydrocarbon polymer and fine particles depends on the use and thickness of the film, but for example, 10 parts by weight with respect to 100 parts by weight of the vinyl alicyclic hydrocarbon polymer. The following is preferable, 5 parts by weight or less is more preferable, and 3 parts by weight or less is still more preferable. Among these, it is particularly preferable that components other than the vinyl alicyclic hydrocarbon polymer and fine particles are not included.

  The thickness of layer B is usually 0.5 μm or more, preferably 1.0 μm or more, more preferably 1.5 μm or more, and usually 10.0 μm or less, preferably 8.0 μm or less, more preferably 7.5 μm or less. It is. By making the thickness of the layer B equal to or higher than the lower limit of the above range, the impact resistance of the film can be sufficiently increased, and by setting the thickness to the upper limit or lower, the retardation of the film is suppressed to be small and the haze is reduced. be able to. The thickness of the layer B can be measured in the same manner as the thickness of the layer A.

  Layer B is preferably located on at least one outermost surface of the film. Since the layer B containing fine particles has excellent slipperiness, when the layer B is located on the outermost surface, the film according to the first example can also exhibit excellent slipperiness, and the handleability of the film is improved. Because it does.

  In addition, it is preferable that at least a part of the layer interface between the layer A and the layer B is in direct contact without an adhesive layer, and the entire layer interface is in direct contact without an adhesive layer. More preferred. Thus, even if the layer A and the layer B are directly laminated without interposing the adhesive layer, both the layer A and the layer B contain the vinyl alicyclic hydrocarbon polymer. It is firmly bonded to B. Therefore, it becomes possible to reduce the thickness of the film by eliminating the need for an adhesive.

  The film which concerns on a 1st example should just be a film which has the layer A and the layer B at least. Therefore, the film according to the first example may be a laminated film including only two layers A and B, or may be a laminated film having three or more layers. For example, the film of the present invention may be a laminated film having two or more of one or both of the layer A and the layer B. At this time, the layer A is preferably not located on the outermost surface of the film. That is, another layer is preferably formed on both sides of the layer A. Especially, it is especially preferable to set it as the laminated film which has layer B, layer A, and layer B in this order by forming layer B on both surfaces of layer A. This is because the component contained in the layer A can be protected by the layer B. Especially, when the layer B contains a ultraviolet absorber, since the bleeding out of the ultraviolet absorber at the time of shaping | molding of a film can be suppressed, it is especially preferable.

  Furthermore, the film according to the first example may have other layers in addition to the layer A and the layer B as long as the effects of the present invention are not significantly impaired. The other layers may be one layer or two or more layers. Moreover, each layer may be the same or different. The positions of other layers can be set arbitrarily.

The film according to the first example is the same as the film composed of only the layer A with respect to at least the in-plane retardation Re, the thickness direction retardation Rth, the light transmittance, and the impact resistance. The film according to the first example is suitable as a polarizing plate protective film because both the layer A and the layer B contain a vinyl alicyclic hydrocarbon polymer, so that the retardation Re is small and the impact resistance is small. Can be used for
Furthermore, since the film according to the first example includes the layer B, the slipperiness of the surface is improved as compared with the film of the layer A alone, and the handleability is good. For this reason, the film which concerns on a 1st example makes it easy to carry out a preservation | save, conveyance etc. in roll shape, and also becomes easy to pull out from a roll at the time of use.

(2) Second Example of Layer Configuration Next, a second example of the layer configuration of the film of the present invention will be described. The film according to the second example is a laminated film including at least layer C in addition to layer A.
Here, the layer C is any selected from the group consisting of (i) polyester, (ii) polycarbonate, (iii) polypropylene, (iv) hydrogenated norbornene polymer, and (v) methacrylate ester-based polymer. Or a layer containing one or more materials.

(I) Polyester As the polyester, any polymer can be used as long as it is a polymer having a repeating unit by an ester bond (hereinafter referred to as “ester component” as appropriate). Moreover, what consists of one type of repeating unit may be used for polyester, and what combined two or more types of repeating units by arbitrary ratios may be used for it. Further, the polyester may be a copolymer having a repeating unit other than the ester component. When the polyester is a copolymer, the polyester may be a random copolymer, a block copolymer, or a graft copolymer. However, even when the polyester has a repeating unit other than the ester component, the content of the ester component contained in the polyester is preferably high. Specifically, the content is preferably 80% by weight or more, and more preferably 85% by weight or more.
Examples of polyesters include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate. In addition, the polyester which the layer C contains may be one type, and may be contained combining two or more types by arbitrary ratios.

The weight average molecular weight of the polyester is a polystyrene equivalent weight average molecular weight measured by gel permeation chromatography, and is usually 5000 or more, preferably 10,000 or more, more preferably 15000 or more, and usually 100,000 or less, preferably 80,000 or less. More preferably, it is 65000 or less.
The melting point of the polyester is usually 210 ° C. or higher, preferably 220 ° C. or higher, more preferably 230 ° C. or higher, and is usually 280 ° C. or lower, preferably 270 ° C. or lower, more preferably 260 ° C. or lower.

(Ii) Polycarbonate Any polycarbonate can be used as long as it is a polymer having a repeating unit (hereinafter referred to as “carbonate component” as appropriate) based on a carbonate bond (—O—C (═O) —O—). . Moreover, what consists of one type of repeating unit may be used for a polycarbonate, and what combined two or more types of repeating units in arbitrary ratios may be used. Further, the polycarbonate may be a copolymer having a repeating unit other than the carbonate component. When the polycarbonate is a copolymer, the polycarbonate may be a random copolymer, a block copolymer, or a graft copolymer. However, even when the polycarbonate has a repeating unit other than the carbonate component, the content of the carbonate component contained in the polycarbonate is preferably high. Specifically, the content is preferably 80% by weight or more, and more preferably 85% by weight or more.
Examples of the polycarbonate include bisphenol A polycarbonate and branched bisphenol A polycarbonate. In addition, the polycarbonate which the layer C contains may be one type, and may be contained combining two or more types by arbitrary ratios.

The weight average molecular weight of the polycarbonate is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography, and is usually 10,000 or more, preferably 30,000 or more, more preferably 50,000 or more, and usually 200,000 or less, preferably 180000 or less. More preferably, it is 160000 or less.
The glass transition temperature of polycarbonate is usually 130 ° C. or higher, preferably 140 ° C. or higher, more preferably 150 ° C. or higher, and is usually 190 ° C. or lower, preferably 180 ° C. or lower, more preferably 170 ° C. or lower.

(Iii) Polypropylene Polypropylene may be a homopolymer of propylene or a copolymer with a monomer other than propylene. When polypropylene is a copolymer, the polypropylene may be a random polymer, a block copolymer, or a graft polymer. However, even when the polypropylene is a copolymer, it is preferable that the content of the propylene-derived repeating unit contained in the polypropylene is high, specifically, 80% by weight or more is preferable, and 85% by weight or more is more preferable. . In addition, the polypropylene which the layer C contains may be one kind, and may be contained combining two or more kinds by arbitrary ratios.

The weight average molecular weight of polypropylene is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography, and is usually 10,000 or more, preferably 20,000 or more, more preferably 25,000 or more, and usually 200,000 or less, preferably 180000 or less. More preferably, it is 150,000 or less.
The melting point of polypropylene is usually 100 ° C. or higher, preferably 110 ° C. or higher, more preferably 120 ° C. or higher, and is usually 170 ° C. or lower, preferably 160 ° C. or lower, more preferably 150 ° C. or lower.

(Iv) Hydrogenated norbornene polymer The hydrogenated norbornene polymer is a hydride of a norbornene polymer. Examples of the norbornene polymer include a ring-opening polymer of a norbornene monomer, a ring-opening copolymer of a monomer copolymerizable with the norbornene monomer, an addition polymer of a norbornene monomer, and a norbornene monomer. And an addition copolymer of a monomer and a copolymerizable monomer.
Among them, a hydride of a ring-opening polymer of a norbornene monomer has good heat resistance and mechanical strength, and can be particularly preferably used.

Examples of the norbornene monomer include bicyclo [2.2.1] hept-2-ene (also known as norbornene), tricyclo [5.2.1.0 ^2,7 ] deca-3,8-diene (also known as diene). Cyclopentadiene), tetracyclo [7.4.1 ^10,13 . 0 ^1,9 . 0 ^2,7 ] trideca-2,4,6,11-tetraene (also known as methanotetrahydrofluorene), tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] dodec-3-ene (also known as tetracyclododecene), derivatives having substituents on these rings, and the like. Examples of the substituent include an alkyl group, an alkylene group, and an alkoxycarbonyl group. In addition, a substituent can have 1 piece or 2 or more pieces. Examples of such derivatives include 8-methoxycarbonyltetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] dodec-3-ene, 8-methyl-8-methoxycarbonyltetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] dodec-3-ene and the like. In addition, a norbornene monomer may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

A ring-opening polymer of norbornene monomer and a ring-opening copolymer with other monomers copolymerizable with norbornene monomer are obtained by polymerizing the monomer in the presence of a ring-opening polymerization catalyst. It is done. Examples of the ring-opening polymerization catalyst include a metal halide such as ruthenium and osmium, a catalyst comprising a nitrate or acetylacetone compound and a reducing agent; a metal halide such as titanium, zirconium, tungsten and molybdenum, or an acetylacetone compound and an organoaluminum compound. A catalyst consisting of: and the like.
Examples of the other monomer capable of ring-opening copolymerization with the norbornene monomer include monocyclic olefins such as cyclohexene, cycloheptene, and cyclooctene. In addition, the other monomer copolymerizable with these norbornene monomers may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The addition polymer of norbornene monomer and the addition copolymer with other monomer copolymerizable with norbornene monomer can be obtained, for example, by polymerizing the monomer in the presence of an addition polymerization catalyst. . Examples of the addition polymerization catalyst include a catalyst composed of a metal compound such as titanium, zirconium, vanadium and an organoaluminum compound.
Examples of other monomers copolymerizable with norbornene monomers include ethylene, propylene, 1-butene, 1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1- Α-olefins having 2 to 20 carbon atoms such as hexadecene, 1-octadecene, 1-eicosene and the like; and derivatives thereof; cyclobutene, cyclopentene, cyclohexene, cyclooctene, 3a, 5,6,7a-tetrahydro-4,7- Cycloolefins such as methano-1H-indene, and derivatives thereof; non-conjugated such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 1,7-octadiene Diene; and the like. Of these, α-olefins are preferred and ethylene is particularly preferred. In addition, the other monomer copolymerizable with these norbornene monomers may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  In the copolymer of the norbornene monomer and other monomers copolymerizable, the ratio of the norbornene component in the copolymer is preferably 30% by weight or more, more preferably 50% by weight. Preferably, it is 70% by weight or more.

The hydride of norbornene polymer can be obtained, for example, by containing a hydrogenation catalyst containing a transition metal such as nickel or palladium in a solution of norbornene polymer and hydrogenating a carbon-carbon unsaturated bond.
In addition, the hydrogenated norbornene polymer included in the layer C may be one type, or two or more types may be included in combination at an arbitrary ratio.

The weight average molecular weight of the hydrogenated norbornene polymer is usually 5,000 or more, preferably 8,000 or more, more preferably 10,000 or more, and usually 500, in terms of polystyrene measured by gel permeation chromatography. , 000 or less, preferably 200,000 or less, more preferably 100,000 or less.
The glass transition temperature of the hydrogenated norbornene polymer is usually 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher, and usually 250 ° C. or lower, preferably 200 ° C. or lower.

(V) Methacrylic acid ester polymer The methacrylic acid ester polymer is a polymer mainly composed of methacrylic acid ester (M1). It is a homopolymer of methacrylic acid ester, and methacrylic acid ester and other single polymers. And a copolymer with a monomer. As the methacrylic acid ester (M1), alkyl methacrylate is usually used. In the case of a copolymer, examples of other monomers copolymerizable with methacrylic acid esters include acrylic acid esters, aromatic vinyl compounds, and vinylcyan compounds.
Among them, a methacrylic acid ester polymer is an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, an acrylate ester (M2), and a compound having a vinyl group copolymerizable therewith if necessary ( A polymer obtained by polymerization of a monomer containing M3) is preferred.

Examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate and the like, and methyl methacrylate is particularly preferable.
As the acrylate ester (M2), alkyl acrylate is usually used, and the alkyl group preferably has 1 to 8 carbon atoms. Examples include methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, and the like.
The compound (M3) having a vinyl group that can be copolymerized with an alkyl methacrylate (M1) and / or an acrylic ester (M2) is a variety of monomers that are conventionally known in the field of methacrylic polymers. it can. For example, aromatic vinyl compounds such as styrene, vinylcyan compounds such as acrylonitrile, and the like can be given.
Each of these monomers may be used alone or in combination of two or more at any ratio.

As for the methacrylic acid ester polymer, methacrylic acid ester (M1) is usually 50% by weight or more, usually 100% by weight or less, preferably 99.9% by weight or less, more preferably 99.5% by weight or less. (M2) is usually 0% by weight or more, preferably 0.1% by weight or more, more preferably 0.5% by weight or more and usually 50% by weight or less, and the compound (M3) having a vinyl group copolymerizable therewith. ) Is usually obtained by polymerizing 0 wt% or more and usually 49 wt% or less.
In addition, the methacrylate polymer which the layer C contains may be one type, and two or more types may be included in combination at an arbitrary ratio.

  The weight average molecular weight of the methacrylic acid ester polymer is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography, and is usually 10,000 or more, preferably 15,000 or more, more preferably 20,000 or more, and usually 300,000 or less. , Preferably 250,000 or less, more preferably 200000 or less.

  The glass transition temperature of the methacrylic acid ester polymer is usually 40 ° C. or higher, preferably 60 ° C. or higher. If the glass transition temperature of the methacrylic acid ester polymer is too low, the heat resistance of the film may be lowered. The glass transition temperature can be appropriately set by changing the type and amount of other monomers copolymerized with the methacrylic acid ester. Moreover, since the glass transition temperature of the homopolymer of methyl methacrylate is about 106 ° C., when methyl methacrylate is used as the methacrylate ester, the glass transition temperature of the resulting methacrylate polymer is usually 106 ° C. or less. It becomes.

  Here, the methacrylic ester polymer includes a methacrylic ester polymer composition containing predetermined rubber particles. The rubber particles contained in the methacrylic acid ester polymer composition have an average particle diameter of usually 0.05 μm or more, and usually 0.3 μm or less, preferably 0.2 μm or less. be able to. When the average particle diameter of the rubber particles is within this range, the film-forming property of the film is stabilized and the film itself is excellent in flexibility and handling properties. If the average particle size of the rubber particles is too small, the flexibility of the film will decrease and the handling will tend to be reduced. On the other hand, if the average particle size is too large, the surface smoothness will decrease and the transparency will be impaired. There is a risk of being.

  The average particle diameter of the rubber particles can be obtained by mixing the rubber particles with a methacrylic polymer to form a film, dyeing the cross section with ruthenium oxide, and observing the diameter of the dyed particles with an electron microscope. . As a result, even when the surface of the rubber particles is covered with a methacrylic polymer as will be described later, the rubber particles are not dyed by mixing with the methacrylic polymer to be mixed with the outer layer of the methacrylic polymer. Since only the inner layer rubber particles are dyed, the particle diameter of the rubber particles can be determined by observing with an electron microscope or the like.

  As the rubber constituting the rubber particles, those made of various elastic copolymers can be used. Among them, preferably, an alkyl acrylate monomer is 50 to 99.9% by weight, a monofunctional monomer having 1 to 49.9% by weight of a carbon-carbon double bond, and a carbon-carbon double bond. Examples thereof include a copolymer of 0.1 to 10% by weight of a polyfunctional monomer having at least two.

  Examples of the alkyl acrylate include those having 1 to 8 carbon atoms in the alkyl group. Of these, alkyl groups having 4 to 8 carbon atoms such as butyl acrylate and 2-ethylhexyl acrylate are preferable. In addition, alkyl acrylate may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  Examples of the monofunctional compound having one carbon-carbon double bond in one molecule include methacrylic acid esters such as methyl methacrylate, butyl methacrylate, and cyclohexyl methacrylate; aromatic vinyl compounds such as styrene; acrylonitrile Vinylcyan compounds such as; and the like. In addition, the monofunctional compound which has one carbon-carbon double bond in 1 molecule may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  Examples of the polyfunctional compound having at least two carbon-carbon double bonds in one molecule include unsaturated carboxylic acid diesters of glycols such as ethylene glycol dimethacrylate and butanediol dimethacrylate; allyl acrylate, methacryl Alkenyl esters of unsaturated carboxylic acids such as allyl acrylate and allyl cinnamate; polyalkenyl esters of polybasic acids such as diallyl phthalate, diallyl maleate, triallyl cyanurate, triallyl isocyanurate; trimethylolpropane triacrylate, etc. An unsaturated carboxylic acid ester of a polyhydric alcohol; divinylbenzene and the like. Of these, alkenyl esters of unsaturated carboxylic acids and polyalkenyl esters of polybasic acids are preferred. The polyfunctional compound having at least two carbon-carbon double bonds in one molecule preferably has crosslinkability. In addition, the polyfunctional compound which has at least 2 carbon-carbon double bond in 1 molecule may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  The rubber particles can be produced, for example, by emulsion polymerization of the above monomer. The average particle size can be adjusted by adjusting the amount of emulsifier and the amount of monomer charged in the emulsion polymerization.

Furthermore, the surface of the rubber particles may be covered with a methacrylic polymer. The methacrylic polymer is a resin having a methacrylic acid or methacrylic ester structure as a repeating unit, and is preferably the same as the methacrylic ester polymer. Among these, more preferably, the methacrylic acid ester (M1) is 50 to 100% by weight, the acrylic acid ester (M2) is 0 to 50% by weight, and the vinyl group-containing compound (M3) is 0 to 49% by weight. It is obtained by polymerizing a monomer composition.
When the surface of the rubber particle is covered with a methacrylic polymer, an outer layer made of a methacrylic polymer is formed on the surface of the rubber particle. The average particle diameter of the rubber particles including the outer layer is preferably 0.07 μm or more, more preferably 0.1 μm or more, preferably 0.5 μm or less, more preferably 0.45 μm or less. The rubber particles may have another layer other than the outer layer made of a methacrylic polymer.

When producing rubber particles whose surfaces are covered with a methacrylic polymer, the monomer of the methacrylic polymer may be polymerized in the presence of the rubber particles. As a result, the methacrylic polymer monomer is graft-copolymerized to the rubber particles, and the rubber particles can be produced as a crosslinked elastic copolymer having a graft chain. Usually, the rubber particles are a graft copolymer having a multilayer structure containing alkyl acrylate as a main component of rubber.
The amount of the methacrylic polymer monomer during the polymerization may be 10 to 400 parts by weight of the methacrylic polymer monomer with respect to 100 parts by weight of the rubber particles. Specifically, in the presence of 100 parts by weight of rubber particles, the methacrylic polymer monomer is usually 10 parts by weight or more, preferably 20 parts by weight or more, and usually 400 parts by weight or less, preferably 200 parts by weight or less. By polymerizing only the polymer layer, at least one layer of a polymer layer made of a methacrylic polymer can be bonded to the surface of the rubber particles. When the amount of the methacrylic polymer monomer is within the above range, the rubber particles are less likely to aggregate, and the transparency of the film is improved. If the amount of the methacrylic polymer monomer is out of the above range, the fluidity of the entire composition of the methacrylic acid ester polymer in which rubber particles are dispersed may be lowered, and film formation may be difficult. . In this polymerization, the reaction conditions can be adjusted so that the average particle diameter of the rubber particles falls within a desired range.

  Further, the rubber particles further have an inner core layer on the inner side, and the inner core layer comprises 70 to 100% by weight of a methacrylic acid ester (M4) and 0 to 30% by weight of a compound having a vinyl group (M5) ( More preferably, it comprises a (co) polymer. It is particularly preferable that the rubber particles have a structure of three or more layers from the viewpoints of elastic modulus, surface smoothness, surface hardness and the like when a film is formed. Thus, the rubber particles having a structure of three or more layers, for example, polymerize the monomer of the (co) polymer constituting the inner core layer, and then constitute the rubber in the presence of the obtained polymer. It can be produced by polymerizing a polymer monomer and polymerizing a methacrylic polymer monomer in the presence of the rubber particles thus obtained.

As said methacrylic acid ester (M4), alkyl methacrylate, especially methyl methacrylate is advantageous. Examples of the compound (M5) having a vinyl group used arbitrarily include acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, and cyclohexyl acrylate; aromatic vinyl compounds such as styrene; vinyl such as acrylonitrile. A cyanide compound; and the like. The vinyl group-containing compound (M5) is preferably a copolymerizable cross-linkable substance. As such a substance, the same compound as the polyfunctional compound having at least two carbon-carbon double bonds in one molecule can be used. In addition, as for the methacrylic acid ester (M4) and the compound (M5) having a vinyl group, one type may be used, or two or more types may be used in combination at an arbitrary ratio.
Such rubber particles having a three-layer structure are disclosed in, for example, Japanese Patent Publication No. 55-27576 (US Pat. No. 3,793,402). In particular, the one described in Example 3 of the publication is one of the preferred compositions.

  In a methacrylic ester polymer composition containing rubber particles, when the total amount of the composition is 100 wt%, the rubber particles are usually 1 wt% or more, preferably 5 wt% or more, more preferably 10 wt%. It is contained in an amount of not less than wt%, usually not more than 80 wt%, preferably not more than 35 wt%, more preferably not more than 25 wt%. When the amount of the rubber particles is within such a range, the film will not become brittle, the film-forming property of the layer C can be improved, and the layer C can be stretched without breaking. If the amount of rubber particles is too small, the layer C may be difficult to mold, and if the amount is too large, the transparency and surface hardness of the layer C may be impaired. The proportion of the methacrylic ester polymer is usually 20 to 99% by weight, but when other additives other than the methacrylic ester polymer and rubber particles are included, the proportion can be adjusted as appropriate. it can.

The methacrylic ester polymer composition containing rubber particles has a melt viscosity of usually 400 Pa · s or higher, preferably 450 Pa · s or higher, and usually 1000 Pa · s or lower, preferably 900 Pa · s or lower. Here, the melt viscosity is a value measured at a temperature of 250 ° C. and a shear rate of 150 sec ⁻¹ . By having such a melt viscosity, breakage or the like hardly occurs when stretching, and the strength during stretching and use of the product can be further improved.

A material to be specifically included in the layer C from the above-mentioned (i) polyester, (ii) polycarbonate, (iii) polypropylene, (iv) hydrogenated norbornene polymer, and (v) methacrylic ester polymer. When selecting, it is preferable to select a material that is not compatible with the vinyl alicyclic hydrocarbon polymer constituting the layer A and that makes the layer A and the layer C easy to peel off. Specifically, the difference between the solubility parameter of the vinyl alicyclic hydrocarbon polymer constituting the layer A and the solubility parameter of the material contained in the layer C is usually 1 (cal ^1/2 / cm ^3/2. ) Or more, preferably 2 (cal ^1/2 / cm ^3/2 ) or more. As a simple method for determining the solubility parameter, P.I. A. Small molar intermolecular attractive constants can be used. Usually, the layer C is peeled off when the film of the present invention is used. Therefore, if the layer A and the layer C are easily peeled off, the peeling is facilitated.

  As long as the effect of the present invention is not significantly impaired, the layer C includes the above-mentioned (i) polyester, (ii) polycarbonate, (iii) polypropylene, (iv) hydrogenated norbornene polymer, and (v) methacrylic ester heavy polymer. Other components may be included in addition to the coalescence. However, the amount of other components is preferably small from the viewpoint of remarkably exhibiting the effects of the present invention. Specific amounts of the other components depend on the use and thickness of the film. For example, (i) polyester, (ii) polycarbonate, (iii) polypropylene, (iv) hydrogenated norbornene polymer, and (v ) It is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, and still more preferably 3 parts by weight or less, based on 100 parts by weight of the total weight of the methacrylic ester polymer. Among these, it is particularly preferable that other components are not included.

  The thickness of the layer C is usually 10 μm or more, preferably 12 μm or more, more preferably 15 μm or more, and usually 25 μm or less, preferably 23 μm or less, more preferably 20 μm or less. By setting the thickness of the layer C to be equal to or more than the lower limit of the above range, handling properties such that the layer C is hardly broken after peeling are improved. Moreover, when it is made below the upper limit, it will not peel when passing a roll at the time of film forming. The thickness of the layer C can be measured in the same manner as the thickness of the layer A.

  The layer A and the layer C are preferably in direct contact with at least part of the layer interface without going through the adhesive layer, and more preferably the whole of the layer interface is in direct contact without going through the adhesive layer. . Although the layer C is peeled off from the film when the film is used, the layer C usually has a property of being easily peeled off from the layer A. For this reason, from the viewpoint of facilitating peeling of the layer C performed at the time of use, the layer A and the layer C are directly laminated without using an adhesive layer at the time of storage and transportation, and the layer A is protected by the layer C. It is preferable that the layer C is easily peeled off from the film by using the property of the layer C being easily peeled off during use.

  The degree of ease of peeling between layer A and layer C may be set arbitrarily, but the peeling force between layer A and layer C is usually 1 g / cm or more, usually 100 g / cm or less, preferably 50 g / cm. It is preferable that peeling is easy, but if it can be peeled off very easily, delamination may occur during film transport.

  In general, the layer C is more slippery than the layer A. For this reason, the film which concerns on a 2nd example by having the layer C has favorable handleability.

  The film which concerns on a 2nd example should just be a film which has the layer A and the layer C at least. Therefore, the film according to the second example may be a laminated film including only two layers A and C, or may be a laminated film having three or more layers. For example, the film of the present invention may be a laminated film having two or more of one or both of the layer A and the layer C. At this time, the layer A is preferably not located on the outermost surface of the film. That is, another layer is preferably formed on both sides of the layer A. Especially, it is especially preferable to set it as the laminated | multilayer film which has the layer C, the layer A, and the layer C in this order by forming the layer C on both surfaces of the layer A. This is because the layer A can be protected from scratches and the like.

  Furthermore, the film according to the second example may have other layers in addition to the layer A and the layer C as long as the effects of the present invention are not significantly impaired. The other layers may be one layer or two or more layers. Moreover, each layer may be the same or different. The positions of other layers can be set arbitrarily.

As described above, the film according to the second example is used by peeling the layer C from the film at the time of use. Accordingly, the in-plane retardation Re, thickness direction retardation Rth, light transmittance and impact resistance after peeling off the layer C are preferably excellent as in the case of the film comprising only the layer A. . Usually, the layer A remains in the film according to the second example after the layer C is peeled off, and the excellent performance of the layer A is exhibited. Therefore, the phase difference Re is small, and the impact resistance is small. It can be suitably used as a polarizing plate protective film.
Furthermore, since the film according to the second example includes the layer C before the layer C is peeled off, the slipperiness of the surface is improved as compared with the film of the layer A alone, and the handleability is good. is there. For this reason, the film according to the second example is easy to be stored and transported in the form of a roll, and is further easily pulled out from the roll during use.

[2. Film production method]
There is no restriction | limiting in particular in the manufacturing method of the film of this invention, Either a melt molding method or a solution casting method can be used. The melt molding method can be further classified into an extrusion molding method, a press molding method, an inflation molding method, an injection molding method, a blow molding method, and a stretch molding method. Among these methods, in order to obtain a film excellent in mechanical strength, surface accuracy, etc., an extrusion molding method, an inflation molding method or a press molding method is preferable. Among them, the efficiency is improved while suppressing the development of retardation more reliably. From the viewpoint of easily and easily producing the film of the present invention, the extrusion method is particularly preferable.

  When the film of the present invention is produced as a laminated film, for example, a coextrusion molding method such as a coextrusion T-die method, a coextrusion inflation method, or a coextrusion lamination method; a film lamination molding method such as dry lamination; On the other hand, a known method such as a coating molding method in which a resin solution constituting other layers is coated can be appropriately used. Among them, the coextrusion molding method is preferable from the viewpoint of good production efficiency and preventing volatile components such as a solvent from remaining in the film. Among the coextrusion molding methods, the coextrusion T-die method is preferable. Further, examples of the coextrusion T-die method include a feed block method and a multi-manifold method, but the multi-manifold method is more preferable in that variation in the thickness of the layer A can be reduced.

For example, when the film according to the first example of the layer structure of the film of the present invention described above is produced by a coextrusion method, at least a resin containing a vinyl alicyclic hydrocarbon polymer or the like constituting the layer A, and a layer The vinyl alicyclic hydrocarbon polymer constituting B and the resin containing fine particles may be coextruded and cured to be molded.
Further, for example, when the film according to the second example of the layer structure of the film of the present invention described above is produced by a coextrusion method, at least a resin containing a vinyl alicyclic hydrocarbon polymer or the like constituting the layer A and A resin containing materials such as polyester, polycarbonate, polypropylene, hydrogenated norbornene polymer, and methacrylic acid ester polymer constituting the layer C may be coextruded and cured to be molded.

However, when a film is produced by extrusion (including coextrusion), the set temperature of the die at the time of extrusion is Tg _A +100 based on the glass transition temperature Tg _A of the vinyl alicyclic hydrocarbon polymer. ° C. or higher, Tg _A + 110 ° C. or higher is more preferable, Tg _A + 135 ° C. or lower is preferable, and Tg _A + 130 ° C. or lower is more preferable. By making the set temperature of the die more than the lower limit of the above range, it is possible to further suppress the expression of the phase difference between the layer A and the film, and by making it below the upper limit of the above range of the vinyl alicyclic hydrocarbon polymer. Deterioration can be stably prevented.

  Further, in order to make the variation in the thickness of the layer A within ± 1 μm over the entire surface, (1) a polymer filter having an opening of 20 μm or less is provided in the extruder; (2) the gear pump is rotated at 5 rpm or more; 3) Surrounding means is arranged around the die; (4) Air gap is 200 mm or less; (5) Edge pinning is performed when the film is cast on a cooling roll; (6) Twin screw extruder as an extruder Alternatively, it is desirable to use a single-screw extruder having a double flight type screw type. Unless even one of the above (1) to (6) is carried out, it tends to be difficult to make the variation in the thickness of the layer A within ± 1 μm over the entire surface.

When a melt extrusion method is used as a method for producing a film, the molten resin is usually coextruded from a die opening onto a cast roll and then brought into contact with a cooling drum. When brought into contact with the cooling drum, the molten resin is cooled and cured to obtain a film. The degree of contact between the molten resin and the cooling drum is preferably in close contact from the viewpoint of sufficient cooling. Examples of the method for bringing the molten resin into close contact with the cooling drum include an air knife method, a vacuum box method, and an electrostatic contact method. The number of cooling drums is not particularly limited, but is usually two or more. Furthermore, examples of the arrangement method of the cooling drum include a linear type, a Z type, and an L type. Further, the way of passing the molten resin extruded from the opening of the die through the cooling drum is not particularly limited.
Normally, the degree of adhesion of the extruded resin to the cooling drum changes depending on the temperature of the cooling drum. When the temperature of the cooling drum is raised, the adhesion is improved, but when the temperature is raised too much, the film may not be peeled off from the cooling drum and may be wound around the drum. Therefore, the temperature of the cooling drum is preferably (Tg + 30) ° C. or less, more preferably (Tg-5) ° C. to (Tg−) with respect to Tg (° C.) of the glass transition temperature of the amorphous resin extruded from the die. 45) Set to a range of ° C. By doing so, it is possible to prevent problems such as slipping and scratches.

Furthermore, the film of the present invention produced by extrusion is usually drawn into a stretched film. The stretching conditions are not particularly limited, but it is preferable that the stretching temperature is 20 ° C. to 60 ° C. higher than the glass transition temperature or melting point of the layer B or C, and the stretching ratio is 1.1 times to 6 times. When the glass transition temperature or the melting point of the layer B or the layer C is different, the higher temperature is used as a reference. The stretching direction may be a film flow direction (MD direction), a film width direction (TD direction), or an oblique direction that is neither parallel nor orthogonal to the film flow direction.
Furthermore, it is good also as a biaxially stretched film by giving a biaxial stretching process. The layer A of the film of the present invention has an excellent property that the retardation Re is hardly exhibited even when the biaxial stretching treatment is performed. Further, when the biaxial stretching treatment is performed, the impact resistance of the layer A is usually improved. For this reason, the biaxial stretching process can improve the impact resistance of the film of the present invention while keeping the phase difference Re small.

As a biaxial stretching method, sequential biaxial stretching may be performed or simultaneous biaxial stretching may be performed. Among these, simultaneous biaxial stretching, which is a method with higher productivity, is preferable.
Simultaneous biaxial stretching refers to stretching in the machine direction (ie, extending the length of the film along the film transport direction) and stretching in the transverse direction (ie, along the direction perpendicular to the film transport direction). (Width expansion) refers to a mode of stretching performed at least in part at the same time. Preferably, stretching in the longitudinal direction and the transverse direction are started simultaneously and ended simultaneously.

  The stretching machine that performs simultaneous biaxial stretching is not particularly limited, and a linear motor system, a pantograph system, a motor chain drive system, or the like can be used. Of these, a pantograph type stretching machine is preferable because of its advantage that the structure is simple and the entire production line including the stretching machine can be quickly started up.

  The draw ratio can be appropriately adjusted according to the desired conditions, but is preferably 1.1 times or more, more preferably 1.2 times or more, and preferably 2 times or less, in the longitudinal direction and the transverse direction, respectively. More preferably, it is 1.5 times or less. By setting it as the draw ratio of this range, the biaxially stretched film suitable for an optical film can be obtained, and the thickness and orientation of a film can be made uniform.

  The unstretched film stretched in the simultaneous biaxial stretching process is usually continuously supplied in the length direction. Although the width | variety of a film is not specifically limited, Usually, it is 450 mm or more, Preferably it is 1000 mm or more, Usually, it is 2000 mm or less, Preferably it is 1500 mm or less. Moreover, the thickness of a film is 40 micrometers or more normally, Preferably it is 60 micrometers or more, and is 400 micrometers or less normally, Preferably it is 300 micrometers or less.

The stretching temperature is preferably Tg _A −5 (° C.) to Tg _A +30 (° C.) based on the glass transition temperature Tg _A of the vinyl alicyclic hydrocarbon polymer. Furthermore, it is preferable to control the temperature unevenness in the region where the film is stretched within ± 0.5 ° C. By performing such temperature control, the orientation of the film can be made uniform.
As a preferable configuration of the simultaneous biaxial stretching machine that achieves such temperature control, it is possible to include an oven that surrounds a region where stretching is performed. Furthermore, the oven has a staggered heater, a fan connected to each heater, a duct that distributes the hot air from the fan to the top and bottom of the oven, and a nozzle that blows the hot air from the duct to the film in the oven over a wide range. By providing, temperature control can be achieved more satisfactorily. Furthermore, a sensor for detecting the temperature in the vicinity of the film in the oven, and a controller for controlling the operation of the heater and the fan manually or automatically based on data detected by the sensor may be further provided. Moreover, you may make it further provide the valve etc. which control manually or automatically the distribution of the warm air from a fan to the upper and lower ducts based on the instruction | indication from a sensor and a control apparatus as needed.

  Furthermore, it is preferable that the heating means of the oven includes a filter such as a HEPA filter for removing foreign matters such as dust in the air blown out from the nozzle to the film in the oven. Thereby, a higher quality optical film can be manufactured.

  Moreover, it is preferable to control the moving speed of the film in the oven in the vertical direction with high accuracy. Specifically, it is preferable to use a drive device having a rotational accuracy of 1 / 30,000 as the drive device that rotates the sprocket that drives the link device. By performing such control, a film having a more uniform orientation can be produced.

  The mode of supplying the unstretched film to the stretching machine is not particularly limited, and the film can be fed out from a previously prepared roll of unstretched film or supplied, or the extruded film is continuously stretched in-line. It can also be fed continuously to the machine. In particular, the latter case is preferable because there are advantages that the manufacturing process can be made more efficient and the manufacturing equipment can be downsized.

[3. Polarizer]
Since the film of the present invention has a small in-plane retardation Re and excellent impact resistance, it can be used as an optical element and a protective film for the optical element. Examples thereof include members used in display devices such as liquid crystal display devices. Specific examples thereof include a polarizing plate protective film, a retardation film, a brightness enhancement film, a transparent conductive film, a touch panel substrate, a liquid crystal substrate, and light. Examples include a diffusion sheet and a prism sheet. The film of the present invention is particularly suitable for use as a polarizing plate protective film.

When using the film of this invention as a polarizing plate protective film, a polarizing plate is provided with the film of this invention, and a polarizing film. At this time, the film of the present invention is usually provided on both sides of the polarizing film. For example, the film of the present invention is laminated on one side or both sides of a polarizing film via an appropriate adhesive.
Any polarizing film can be used, for example, a polyvinyl alcohol film doped with iodine or the like and then stretched can be used. Moreover, as an adhesive layer, the adhesive etc. which use polymers, such as an acrylic polymer, a silicone type polymer, polyester, a polyurethane, polyether, and a synthetic rubber, as a base polymer are mentioned, for example.

  You may make it provide another layer in the said polarizing plate further. Other layers include, for example, an antireflection layer, a hard coat layer, a primer layer; an anchor layer; a highly homogeneous transparent porous material layer (refracted) composed of a three-dimensional skeleton of SiOx (x = 1.5 to 2.0) ultrafine particles. Rate 1.25 to 1.46); pressure-sensitive adhesive layer; antifouling layer; and the like.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples, and can be arbitrarily modified and implemented without departing from the gist of the present invention. In the following examples, “part” indicating the amount represents “part by weight” unless otherwise specified.

[Synthesis Example 1: Synthesis of polymers of Examples 1 and 3]
A stainless steel reactor equipped with a stirrer and thoroughly dried and purged with nitrogen was charged with 320 parts of dehydrated cyclohexane, 45 parts of styrene monomer and 0.38 part of dibutyl ether and stirred at 60 ° C. with n-butyllithium. The polymerization reaction was started by adding 0.36 part of a solution (15% by weight containing hexane solution). After carrying out the polymerization reaction for 1 hour, 15 parts of isoprene monomer was added to the reaction solution, and after further polymerization reaction for 1 hour, 40 parts of styrene monomer was added to the reaction solution, and the polymerization reaction was further carried out for 1 hour. Went. Thereafter, 0.2 part of isopropyl alcohol was added to the reaction solution to stop the reaction.
When the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained block copolymer were measured, they were Mw = 75,100 and Mw / Mn = 1.11.

  Next, 400 parts of the polymerization reaction solution was transferred to a pressure-resistant reactor equipped with a stirrer, and a silica-alumina supported nickel catalyst (manufactured by JGC Chemical Industry Co., Ltd .; E22U, nickel supported amount 60%) 10 as a hydrogenation catalyst. Part was added and mixed. The inside of the reactor was replaced with hydrogen gas, and hydrogen was supplied while stirring the solution, and a hydrogenation reaction was performed at a temperature of 160 ° C. and a pressure of 4.5 MPa for 8 hours.

  After completion of the hydrogenation reaction, the reaction solution is filtered to remove the hydrogenation catalyst, and then diluted by adding 800 parts of cyclohexane, and the reaction solution is filtered with 3500 parts of isopropanol (class 1000 clean room with a filter having a pore diameter of 1 μm. The block copolymer was precipitated by filtration into a filtered product), separated and recovered by filtration, and dried under reduced pressure at 80 ° C. for 48 hours. The obtained block copolymer is composed of a block containing a repeating unit derived from styrene (hereinafter referred to as “St” as appropriate) and a block containing a repeating unit derived from isoprene (hereinafter referred to as “Ip” as appropriate). The weight ratio of each block was St: Ip: St = 45: 15: 40. The block copolymer had an Mw of 68,000, an Mw / Mn of 1.17, a hydrogenation rate of the main chain and the aromatic ring of 99.9%, and a glass transition temperature Tg of 141.5 ° C.

[Synthesis Example 2: Synthesis of polymer of Example 2]
A stainless steel reactor equipped with a stirrer and thoroughly dried and purged with nitrogen was charged with 320 parts of dehydrated cyclohexane, 45 parts of styrene monomer and 0.38 part of dibutyl ether and stirred at 60 ° C. with n-butyllithium. The polymerization reaction was started by adding 0.36 part of a solution (15% by weight containing hexane solution). After carrying out the polymerization reaction for 1 hour, 12 parts of isoprene monomer was added to the reaction solution, and after further polymerization reaction for 1 hour, 42 parts of styrene monomer was added to the reaction solution, and the polymerization reaction was further carried out for 1 hour. Went. Thereafter, 0.2 part of isopropyl alcohol was added to the reaction solution to stop the reaction.
When the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained block copolymer were measured, they were Mw = 103,000 and Mw / Mn = 1.13.

  A hydrogenation reaction was carried out in the same manner as in Example 1. The obtained block copolymer was a ternary block copolymer composed of St and Ip, and the weight ratio of each block was St: Ip: St = 45: 12: 43. The block copolymer had Mw of 92,000, Mw / Mn of 1.19, a hydrogenation rate of 99.9%, and a glass transition temperature Tg of 146.6 ° C.

[Synthesis Example 3: Synthesis of Polymer of Example 4]
A stainless steel reactor equipped with a stirrer and thoroughly dried and purged with nitrogen was charged with 320 parts of dehydrated cyclohexane, 25 parts of styrene monomer, and 0.38 part of dibutyl ether, and stirred at 60 ° C. with n-butyllithium. The polymerization reaction was started by adding 0.36 part of a solution (15% by weight containing hexane solution). After carrying out the polymerization reaction for 1 hour, 10 parts of isoprene monomer was added to the reaction solution, and after further polymerization reaction for 1 hour, 20 parts of styrene monomer was added to the reaction solution, and the polymerization reaction was further carried out for 1 hour. Then, 5 parts of isoprene monomer was added to the reaction solution, and the polymerization reaction was further performed for 1 hour. Then, 20 parts of styrene monomer was added to the reaction solution, and the polymerization reaction was further performed for 1 hour. Thereafter, 0.2 part of isopropyl alcohol was added to the reaction solution to stop the reaction.
When the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained block copolymer were measured, they were Mw = 92,000 and Mw / Mn = 1.18.

  A hydrogenation reaction was carried out in the same manner as in Example 1. The obtained block copolymer is a ternary block copolymer composed of St and Ip, and the weight ratio of each block is St: Ip: St: Ip: St = 25: 10: 20: 5: It was 20. The block copolymer had an Mw of 88,000, an Mw / Mn of 1.21, a hydrogenation rate of 99.9%, and a glass transition temperature Tg of 125.4 ° C.

[Comparative Synthesis Example 1: Synthesis of Polymer of Comparative Example 1]
A stainless steel reactor equipped with a stirrer and thoroughly dried and purged with nitrogen was charged with 320 parts of dehydrated cyclohexane, 40 parts of styrene monomer and 0.38 part of dibutyl ether, and stirred at 60 ° C. with n-butyllithium. The polymerization reaction was started by adding 0.36 part of a solution (15% by weight containing hexane solution). After carrying out the polymerization reaction for 1 hour, 20 parts of isoprene monomer was added to the reaction solution, and after further polymerization reaction for 1 hour, 40 parts of styrene monomer was added to the reaction solution, and the polymerization reaction was further carried out for 1 hour. Went. Thereafter, 0.2 part of isopropyl alcohol was added to the reaction solution to stop the reaction.
When the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained block copolymer were measured, they were Mw = 103,000 and Mw / Mn = 1.13.

  A hydrogenation reaction was carried out in the same manner as in Example 1. The obtained block copolymer was a ternary block copolymer composed of St and Ip, and the weight ratio of each block was St: Ip: St = 40: 20: 40. The block copolymer had Mw of 72,000, Mw / Mn of 1.17, a hydrogenation rate of 99.9%, and a glass transition temperature Tg of 133.6 ° C.

[Comparative Synthesis Example 2: Synthesis of Polymer of Comparative Example 2]
A stainless steel reactor equipped with a stirrer and thoroughly dried and purged with nitrogen was charged with 320 parts of dehydrated cyclohexane, 50 parts of styrene monomer, and 0.38 part of dibutyl ether, and stirred at 60 ° C. with n-butyllithium. The polymerization reaction was started by adding 0.36 part of a solution (15% by weight containing hexane solution). After carrying out the polymerization reaction for 1 hour, 5 parts of isoprene monomer was added to the reaction solution, and after further polymerizing reaction for 1 hour, 45 parts of styrene monomer was added to the reaction solution, and the polymerization reaction was further carried out for 1 hour. Went. Thereafter, 0.2 part of isopropyl alcohol was added to the reaction solution to stop the reaction.
When the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained block copolymer were measured, they were Mw = 98,000 and Mw / Mn = 1.12.

  A hydrogenation reaction was carried out in the same manner as in Example 1. The obtained block copolymer was a ternary block copolymer composed of St and Ip, and the weight ratio of each block was St: Ip: St = 50: 5: 45. The block copolymer had an Mw of 82,000, an Mw / Mn of 1.19, a hydrogenation rate of 99.9%, and a glass transition temperature Tg of 148.7 ° C.

[Comparative Synthesis Example 3: Synthesis of Polymer of Comparative Example 3]
A stainless steel reactor equipped with a stirrer and thoroughly dried and purged with nitrogen was charged with 320 parts of dehydrated cyclohexane, 85 parts of styrene monomer and 0.38 part of dibutyl ether, and stirred at 60 ° C. with n-butyllithium. The polymerization reaction was started by adding 0.36 part of a solution (15% by weight containing hexane solution). After performing the polymerization reaction for 1 hour, 15 parts of isoprene monomer was added to the reaction solution, and the polymerization reaction was further performed for 1 hour. Thereafter, 0.2 part of isopropyl alcohol was added to the reaction solution to stop the reaction.
When the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained block copolymer were measured, they were Mw = 102,000 and Mw / Mn = 1.14.

  A hydrogenation reaction was carried out in the same manner as in Example 1. The obtained block copolymer was a binary block copolymer composed of St and Ip, and the weight ratio of each block was St: Ip = 85: 15. The block copolymer had an Mw of 89,000, an Mw / Mn of 1.17, a hydrogenation rate of 99.9%, and a glass transition temperature Tg of 110.3 ° C.

[Comparative Synthesis Example 4: Synthesis of Polymer of Comparative Example 4]
A stainless steel reactor equipped with a stirrer and thoroughly dried and purged with nitrogen was charged with 320 parts of dehydrated cyclohexane, 45 parts of styrene monomer and 0.38 part of dibutyl ether and stirred at 60 ° C. with n-butyllithium. The polymerization reaction was started by adding 0.36 part of a solution (15% by weight containing hexane solution). After carrying out the polymerization reaction for 1 hour, 25 parts of a mixed monomer composed of 10 parts of styrene monomer and 15 parts of isoprene monomer was added to the reaction solution, and after further conducting the polymerization reaction for 1 hour, the styrene monomer was added to the reaction solution. 30 parts were added, and the polymerization reaction was further carried out for 1 hour. Thereafter, 0.2 part of isopropyl alcohol was added to the reaction solution to stop the reaction.
When the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained block copolymer were measured, they were Mw = 83,000 and Mw / Mn = 1.16.

  A hydrogenation reaction was carried out in the same manner as in Example 1. The obtained block copolymer is a ternary block copolymer comprising St, a block in which a repeating unit derived from styrene and a repeating unit derived from isoprene coexist (hereinafter referred to as “St / Ip” as appropriate) and Ip. It was a polymer, and the weight ratio of each block was St: St / Ip: St = 45: 10/15: 30. The block copolymer had Mw of 79,000, Mw / Mn of 1.16, a hydrogenation rate of 99.9%, and a glass transition temperature Tg of 138.3 ° C.

[Comparative Synthesis Example 5: Synthesis of Polymer of Comparative Example 5]
A stainless steel reactor equipped with a stirrer and thoroughly dried and purged with nitrogen was charged with 320 parts of dehydrated cyclohexane, 85 parts of styrene monomer and 15 parts of isoprene monomer, and 0.38 part of dibutyl ether. While stirring at 60 ° C., 0.36 part of n-butyllithium solution (15% by weight containing hexane solution) was added to initiate the polymerization reaction. After performing the polymerization reaction for 1 hour, 0.2 part of isopropyl alcohol was added to the reaction solution to stop the reaction.
When the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained random copolymer were measured, they were Mw = 87,000 and Mw / Mn = 1.15.

  A hydrogenation reaction was carried out in the same manner as in Example 1. The obtained random copolymer was a random copolymer composed of St and Ip, and the weight ratio of St and Ip was St: Ip = 85/15. The random copolymer had an Mw of 82,000, an Mw / Mn of 1.19, a hydrogenation rate of 99.9%, and a glass transition temperature Tg of 109.7 ° C.

[Example 1]
(1) Production of Resin A 94% by weight of the block copolymer (vinyl alicyclic hydrocarbon polymer) synthesized in Synthesis Example 1 and 2,2′-methylenebis [4- (1,1,1, 3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol] 5.0% by weight and 2- (4,6-diphenyl-1,3,5-triazin-2-yl)- Add 1.0% by weight of 5-[(hexyl) oxy] -phenol, knead with a twin-screw extruder, extrude into a strand, cut with a pelletizer and vinyl alicyclic structure-containing polymer composition A ( Resin A) was obtained.

(2) Production of Resin B 99.5% by weight of the block copolymer (vinyl alicyclic hydrocarbon polymer) synthesized in Synthesis Example 1 was added as fine particles to silica beads manufactured by Admatechs Co., Ltd. Admafine SO-C2 ( 0.5 wt% of particle size) was mixed and melt kneaded with a twin screw extruder to obtain a vinyl alicyclic structure-containing polymer composition (resin B).

(3) Molding of Extruded Film Resin A and Resin B were supplied to a single screw extruder, and a laminated film was produced by coextrusion molding. The obtained laminated film had a three-layer structure of resin B / resin A / resin B, and the thickness of the obtained laminated film was 5 μm / 20 μm / 5 μm.

[Example 2]
A laminated film having the same thickness was produced in the same manner as in Example 1 except that the block copolymer synthesized in Synthesis Example 2 was used as the block copolymer.

Example 3
(1) Molding of Extruded Film Resin A and Resin B were prepared in the same manner as Example 1.
Resins A and B were supplied to a single screw extruder, and a laminated film was produced by coextrusion molding. The obtained laminated film had a three-layer structure of resin B / resin A / resin B, and the thickness of the obtained laminated film was 6 μm / 24 μm / 6 μm.

(2) Biaxial stretching treatment The obtained laminated film was stretch-molded at a stretching temperature of 147 ° C. with a simultaneous biaxial stretching machine at a stretching ratio of 1.5 times in length and 1.15 times in width.
The thickness of the obtained laminated film was 5 μm / 20 μm / 5 μm.

Example 4
A laminated film having the same thickness was produced in the same manner as in Example 1 except that the block copolymer synthesized in Synthesis Example 3 was used as the block copolymer.

[Comparative Example 1]
A laminated film having the same thickness was produced in the same manner as in Example 1 except that the block copolymer synthesized in Comparative Synthesis Example 1 was used as the block copolymer.

[Comparative Example 2]
A laminated film having the same thickness was produced in the same manner as in Example 1 except that the block copolymer synthesized in Comparative Synthesis Example 2 was used as the block copolymer.

[Comparative Example 3]
A laminated film having the same thickness was produced in the same manner as in Example 1 except that the block copolymer synthesized in Comparative Synthesis Example 3 was used as the block copolymer.

[Comparative Example 4]
A laminated film having the same thickness was produced in the same manner as in Example 1 except that the block copolymer synthesized in Comparative Synthesis Example 4 was used as the block copolymer.

[Comparative Example 5]
A laminated film having the same thickness was produced in the same manner as in Example 1 except that the random copolymer synthesized in Comparative Synthesis Example 5 was used instead of the block copolymer.

[Measurement of phase difference Re]
It measured over 1000 mm at intervals of 50 mm in the width direction of the laminated film with an automatic birefringence meter (Oji Scientific Instruments KOBLA-21ADH). All measurement results were averaged to obtain the in-plane retardation Re value of the laminated film.

(Measurement of impact resistance)
The laminated film was cut into a size of 40 mm in diameter, and 5.5 g of a metal ball was dropped at a different height, and the height at which the film was broken was recorded.
The test was repeated 20 times, and the 50% fracture height was calculated by the method described in JIS K7211-01. If the 50% fracture height is 20 cm or more, “excellent”, less than 20 cm to 17 cm or more “good”, less than 17 cm to 13 cm or more “good”, and less than 13 cm “bad”. .

[Heat resistance test]
A triacetyl cellulose film having an average thickness of 60 μm is bonded to one side of a polarizer A obtained by adsorbing iodine to a polyvinyl alcohol film (average polymerization degree 2400, saponification degree 99.9 mol%, thickness 80 μm), A film X was produced by laminating a laminated film on the other surface using an adhesive (Nitto Denko CS9621).
The obtained film X was cut into A4 size, left in an oven at 80 ° C. for 100 hours, and the dimensional change of the film was measured. If the dimensional change was 0.5 mm or more, it was judged as “bad”, and 0 mm or more and less than 0.5 mm was judged as “good”.

〔Evaluation results〕
The evaluation results of the laminated films produced in each Example and Comparative Example are shown in Table 1 and Table 2 below.

From Table 1, it can be seen that all the laminated films of Examples 1 to 4 of the present invention have a small retardation Re and are excellent in impact resistance and heat resistance. In particular, in Example 3, it can be seen that the impact resistance is remarkably improved by performing the biaxial stretching treatment.
On the other hand, from Comparative Examples 1 and 2 in Table 2, when the content of St which is an aromatic vinyl compound hydride block and the content of Ip which is a diene compound hydride block are out of the range according to the present invention, It can be seen that the phase difference Re increases.
Moreover, it can be seen from Comparative Example 3 in Table 2 that sufficient impact resistance cannot be obtained unless the number of St and Ip blocks is less than 3. Furthermore, it can be seen from Comparative Example 4 in Table 2 that if the diene compound hydride block is a random copolymer of styrene and isoprene, sufficient impact resistance cannot be obtained. Therefore, it can be seen that the impact resistance is insufficient if the block structure according to the present invention is not provided.
Furthermore, it can be seen from Comparative Example 5 in Table 2 that when the polymer is a random copolymer, the phase difference Re is large and the film is inferior in both impact resistance and heat resistance.

  The film of the present invention can be used in any industrial field, but is particularly suitable for use in the field relating to optical elements.

Claims (5)

A film having a layer A containing a vinyl alicyclic hydrocarbon polymer,
The vinyl alicyclic hydrocarbon polymer has a total of 3 or more blocks of aromatic vinyl compound hydride block and diene compound hydride block, and the content of aromatic vinyl compound hydride block is 82% by weight to 90% by weight. %, The content of the diene compound hydride block is 10% by weight to 18% by weight, and at least one end of the polymer chain is composed of an aromatic vinyl compound hydride block,
A film having an in-plane retardation of 1 nm or less. A layer B laminated on the layer A;
The layer B is a layer containing the vinyl alicyclic hydrocarbon polymer and fine particles,
The number average particle diameter of the fine particles is 0.01 μm to 1.0 μm,
The film according to claim 1, wherein a weight ratio of fine particles to the vinyl alicyclic hydrocarbon polymer in the layer B is 0.01% to 5.00%. Layer A containing vinyl alicyclic hydrocarbon polymer, and layer containing any one or more materials selected from the group consisting of polyester, polycarbonate, polypropylene, hydrogenated norbornene polymer, and methacrylic ester polymer A film having C,
The vinyl alicyclic hydrocarbon polymer has a total of 3 or more blocks of aromatic vinyl compound hydride block and diene compound hydride block, and the content of aromatic vinyl compound hydride block is 82% by weight to 90% by weight. %, The content of the diene compound hydride block is 10% by weight to 18% by weight, and at least one end of the polymer chain is composed of an aromatic vinyl compound hydride block,
A film obtained by coextruding a resin containing the vinyl alicyclic hydrocarbon polymer and a resin containing the material.   The film as described in any one of Claims 1-3 in which the said layer A contains a ultraviolet absorber.   The film according to any one of claims 1 to 4, which is a stretched film.