TW201841727A - Optical film, polarizing plate, and image display device - Google Patents

Abstract

Provided is an optical film exhibiting excellent adhesion between a substrate film and a surface-treated layer. The optical film comprises a substrate film, which is a stretched film containing an acrylic resin, and a surface-treated film formed on one side of the substrate film. The substrate film in the optical film has a dimensional change rate of -2.0% to 0% after being left to stand at 100 DEG C for 120 hours in a state in which 10cm*10cm of the substrate film has been cut out and adhered to a glass plate by means of an adhesive.

Description

Optical film, polarizing plate, and image display device

The present invention relates to an optical film, a polarizing plate, and an image display device.

In recent years, an optical film having a functional layer (surface treatment layer) such as a hard coat layer, an anti-glare layer, or an anti-reflection layer formed on one side of a base film including an acrylic resin is known (Patent Document 1). The surface treatment layer can be formed by coating a resin composition on one side of a base film and drying or hardening it. Such an optical film can be used, for example, as a protective film for a polarizing element or as a front panel of an image display device. Prior Art Literature Patent Literature Patent Literature 1: Japanese Patent Laid-Open No. 2016-218478

[Problems to be Solved by the Invention] However, in the step of drying the resin composition in the previous optical film as described above, the base film may be wrinkled due to heat shrinkage, resulting in poor appearance. When the resin composition is dried at a low temperature in order to prevent the abnormality caused by the heat shrinkage as described above, there is a problem that the adhesion between the substrate film and the surface treatment layer becomes insufficient. The present invention has been made in order to solve the above-mentioned problems, and its main object is to provide an optical film with high adhesion between a substrate film and a surface treatment layer, a polarizing plate provided with the optical film, and a polarizing plate provided with the optical film. Image display device. [Technical means to solve the problem] The optical film of the present invention includes a base film as an extension film containing an acrylic resin, and a surface treatment layer formed on one side of the base film, and the base in the optical film described above The dimensional change of the material film when it was cut to 10 cm × 10 cm and bonded to a glass plate through an adhesive material at 100 ° C. for 120 hours was -2.0% to 0%. In one embodiment, the base film includes the acrylic resin and core-shell particles dispersed in the acrylic resin. In one embodiment, the base film contains 5 to 50 parts by weight of the core-shell particles relative to 100 parts by weight of the acrylic resin. In one embodiment, the acrylic resin has a group selected from the group consisting of a glutarimide unit, a lactone ring unit, a maleic anhydride unit, a maleimide unit, and a glutaric anhydride unit. At least one of them. In one embodiment, the surface treatment layer is a hardened layer of a resin composition applied on the substrate film. In one embodiment, the surface treatment layer is at least one selected from the group consisting of a hard coat layer, an anti-glare layer, and an anti-reflection layer. According to another aspect of the present invention, a polarizing plate is provided. The polarizing plate includes a polarizing element and a protective layer disposed on one side of the polarizing element, and the protective layer is the optical film. According to another aspect of the present invention, an image display device is provided. This image display device includes the above-mentioned polarizing plate. [Effects of the Invention] According to the present invention, by using the above-mentioned substrate film having a dimensional change rate of -2.0% to 0%, an optical film with high adhesion between the substrate film and the surface treatment layer can be provided, and the optical film can be provided with such an optical film. A film polarizing plate, and an image display device including such a polarizing plate.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments. A. Overall Structure of Optical Film 1 is a schematic cross-sectional view of an optical film according to an embodiment of the present invention. The optical film 100 includes a base film 10 and a surface treatment layer 20 formed on one side of the base film 10. The base film 10 is an stretched film containing an acrylic resin. The dimensional change rate of the base film 10 in a specific direction when the base film 10 is cut to 10 cm × 10 cm and bonded to a glass plate through an adhesive at 120 ° C. for 120 hours is -2.0% to 0%. The shape of the base film 10 is not particularly limited. For example, when the base film is long or rectangular, typically, the dimensional change rate may be along the long side direction and the short side direction of the base film ( The direction orthogonal to the long side direction) was cut into 10 cm × 10 cm and measured. The specific direction is typically a direction along each side of the substrate film cut into 10 cm × 10 cm. In one embodiment, the base film 10 includes an acrylic resin and core-shell particles dispersed in the acrylic resin. In this case, the base film 10 preferably contains 5 to 50 parts by weight of the core-shell type particles with respect to 100 parts by weight of the acrylic resin. The acrylic resin preferably has at least one selected from the group consisting of a glutarimide unit, a lactone ring unit, a maleic anhydride unit, a maleimide unit, and a glutaric anhydride unit. The surface treatment layer 20 is typically a hardened layer of a resin composition applied on the base film 10. The surface treatment layer 20 is preferably at least one selected from the group consisting of a hard coat layer, an anti-glare layer, and an anti-reflection layer. With the optical film described above, it is possible to suppress shrinkage (especially shrinkage in the extension direction) in a state where the surface-treated layer is formed. As a result, the adhesiveness between the base film 10 and the surface treatment layer 20 can be improved. Especially in the case where the surface treatment layer 20 is formed by applying the resin composition to the base film 10 and drying and curing the resin composition, even in the case where the resin composition is dried at a low temperature, Adequate adhesion between the substrate film 10 and the surface treatment layer 20 can be achieved. Therefore, it is possible to suppress the occurrence of wrinkles in the base film due to the heat when the resin composition is dried. B. Base film B-1. Characteristics of the base film The base film is an stretched film containing an acrylic resin as described above, and is cut into 10 cm × 10 along the long side direction of the base film and its orthogonal direction. The dimensional change rate when the sheet is attached to a glass plate through an adhesive material at 100 ° C. for 120 hours is -2.0% to 2.0%. The above dimensional change rate is preferably -1.8% to 1.0%, more preferably -1.0% to 0.0%, and even more preferably -0.5% to 0.0%. In one embodiment, the base film contains an acrylic resin and core-shell particles dispersed in the acrylic resin. The thickness of the substrate film is preferably 5 μm to 150 μm, and more preferably 10 μm to 100 μm. The substrate film preferably has substantially optical isotropy. In this specification, "substantially optically isotropic" means that the in-plane retardation Re (550) is 0 nm to 10 nm and the retardation Rth (550) in the thickness direction is -10 nm to +10 nm. The in-plane retardation Re (550) is more preferably 0 nm to 5 nm, further preferably 0 nm to 3 nm, and even more preferably 0 nm to 2 nm. The phase difference Rth (550) in the thickness direction is more preferably -5 nm to +5 nm, further preferably -3 nm to +3 nm, and even more preferably -2 nm to +2 nm. If the Re (550) and Rth (550) of the base film are in such ranges, it is possible to prevent adverse effects on display characteristics when the optical film is applied to an image display device. In addition, Re (550) is an in-plane retardation of the film measured at 23 ° C with light having a wavelength of 550 nm. Re (550) can be obtained by the formula: Re (550) = (nx-ny) × d. Rth (550) is the phase difference in the thickness direction of the film measured at 23 ° C using light with a wavelength of 550 nm. Rth (550) can be obtained by the formula: Rth (550) = (nx-nz) × d. Here, the refractive index in the nx plane is the refractive index in the direction where the refractive index becomes the largest (that is, the direction of the late axis), and the refractive index in the ny plane in the direction orthogonal to the late phase axis (that is, the direction of the phase axis) nz is the refractive index in the thickness direction, and d is the thickness (nm) of the film. When the thickness of the substrate film is 30 μm, the higher the light transmittance at 380 nm, the better. Specifically, the light transmittance is preferably 85% or more, more preferably 88% or more, and even more preferably 90% or more. If the light transmittance is in this range, the required transparency can be ensured. The light transmittance can be measured, for example, by a method according to ASTM-D-1003. The lower the haze of the base film, the better. Specifically, the haze is preferably 5% or less, more preferably 3% or less, still more preferably 1.5% or less, and even more preferably 1% or less. When the haze is 5% or less, a good transparency feeling can be imparted to the film. Furthermore, even when an optical film is used as a protective layer of a viewing-side polarizing plate of an image display device, the display content can be viewed well. The YI (Yellowness Index, yellowness index) when the thickness of the substrate film is 30 μm is preferably 1.27 or less, more preferably 1.25 or less, even more preferably 1.23 or less, and even more preferably 1.20 or less. When YI exceeds 1.3, optical transparency may become insufficient. In addition, YI can be based on, for example, the three stimulus values (X, Y, Z) of the color obtained by measurement using a high-speed integrating sphere spectroscopic transmittance measuring machine (trade name DOT-3C: manufactured by Murakami Color Technology Research Institute) It is calculated by the following formula. YI = [(1.28X-1.06Z) / Y] × 100 The b value when the thickness of the substrate film is 30 μm (according to the hue scale of the Hunter color system) is preferably less than 1.5, more It is preferably 1.0 or less. In the case where the b value is 1.5 or more, there are cases where an undesired color tone appears. In addition, the b value can be measured, for example, by cutting a substrate film sample to a size of 3 cm square, and measuring the hue using a high-speed integrating sphere spectroscopic transmittance measuring machine (trade name DOT-3C: manufactured by Murakami Color Technology Research Institute). It is obtained by evaluating the hue with a special color system. The moisture permeability of the base film is preferably 300 g / m ² · 24 hr or less, more preferably 250 g / m ² · 24 hr or less, and further preferably 200 g / m ² · 24 hr or less, particularly preferably 150 g / m ² · 24 hr or less, preferably 100 g / m ² · 24 hr or less. When the moisture permeability of the base film is within this range, when used as a protective layer for a polarizing element, a polarizing plate having excellent durability and moisture resistance can be obtained. The tensile strength of the base film is preferably 10 MPa or more and less than 100 MPa, and more preferably 30 MPa or more and less than 100 MPa. When it is less than 10 MPa, there are cases where sufficient mechanical strength cannot be exhibited. When it exceeds 100 MPa, workability may become insufficient. The tensile strength can be measured in accordance with ASTM-D-882-61T, for example. The tensile elongation of the base film is preferably 1.0% or more, more preferably 3.0% or more, and still more preferably 5.0% or more. The upper limit of the tensile elongation is, for example, 100%. When the tensile elongation is less than 1%, the toughness may be insufficient. The tensile elongation can be measured in accordance with ASTM-D-882-61T, for example. The tensile elastic modulus of the base film is preferably 0.5 GPa or more, more preferably 1 GPa or more, and even more preferably 2 GPa or more. The upper limit of the tensile elastic modulus is, for example, 20 GPa. When the tensile elastic modulus is less than 0.5 GPa, there are cases where sufficient mechanical strength cannot be exhibited. The tensile elastic modulus can be measured in accordance with ASTM-D-882-61T, for example. The substrate film may contain any suitable additive depending on the purpose. Specific examples of the additives include ultraviolet absorbers; hindered phenol-based, phosphorus-based, sulfur-based antioxidants; light-resistant stabilizers, weather-resistant stabilizers, and thermal stabilizers; reinforcing materials such as glass fibers and carbon fibers; Near-infrared absorbing agent; flame retardants such as tris (dibromopropyl) phosphate, triallyl phosphate, antimony oxide; antistatic agents such as anionic, cationic, nonionic surfactants; inorganic pigments, organic Pigments, dyes and other colorants; organic or inorganic fillers; resin modifiers; organic or inorganic fillers; plasticizers; lubricants, etc. Additives may be added during polymerization of the acrylic resin, or may be added during film formation. The type, amount, combination, and addition amount of the additives are appropriately set depending on the purpose. B-2. Acrylic resin B-2-1. Composition of acrylic resin As the acrylic resin, any appropriate acrylic resin can be used. The acrylic resin typically contains, as a monomer unit, an alkyl (meth) acrylate as a main component. In the present specification, "(meth) acrylic acid" means acrylic acid and / or methacrylic acid. Examples of the (meth) acrylic acid alkyl ester constituting the main skeleton of the acrylic resin include those having a linear or branched alkyl group having 1 to 18 carbon atoms. These can be used alone or in combination. Furthermore, any suitable copolymerizable monomer can be introduced into the acrylic resin by copolymerization. The kind, amount, copolymerization ratio, and the like of such copolymerized monomers are appropriately set depending on purposes. The constituent components (monomer units) of the main skeleton of the acrylic resin will be described below with reference to the general formula (2). The acrylic resin preferably has at least one selected from the group consisting of a glutarimide unit, a lactone ring unit, a maleic anhydride unit, a maleimide unit, and a glutaric anhydride unit. An acrylic resin having a lactone ring unit is described in, for example, Japanese Patent Laid-Open No. 2008-181078, and the description of this publication is incorporated herein by reference. The glutariminium unit is preferably represented by the following general formula (1): In the general formula (1), R ¹ and R ² each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R ³ represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, and an alkyl group having 3 to 12 carbon atoms A cycloalkyl group or an aryl group having 6 to 10 carbon atoms. In the general formula (1), it is preferable that R ¹ and R ² are each independently a hydrogen atom or a methyl group, and R ³ is a hydrogen atom, a methyl group, a butyl group, or a cyclohexyl group. More preferably, R ¹ is a methyl group, R ² is a hydrogen atom, and R ³ is a methyl group. The said (meth) acrylic acid alkyl ester is typically represented by the following general formula (2): In the general formula (2), R ⁴ represents a hydrogen atom or a methyl group, and R ⁵ represents a hydrogen atom or an aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms which may be substituted. Examples of the substituent include a halogen and a hydroxyl group. Specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, Tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, (meth) ) 2-hydroxyethyl acrylate, 3-hydroxypropyl (meth) acrylate, 2,3,4,5,6-pentahydroxyhexyl (meth) acrylate, and 2,3,4, (meth) acrylate, 5-tetrahydroxypentyl ester. In the general formula (2), R ^{5 is} preferably a hydrogen atom or a methyl group. Therefore, it is particularly preferable that the alkyl (meth) acrylate is methyl acrylate or methyl methacrylate. The acrylic resin may contain only a single glutarimide unit, or may contain a plurality of glutarimide units having different R ¹ , R ² and R ³ in the general formula (1). The content ratio of the pentamidine imine unit in the acrylic resin is preferably 2 mol% to 50 mol%, more preferably 2 mol% to 45 mol%, and further preferably 2 mol% to 40 mol%, particularly preferably 2 mol% to 35 mol%, and most preferably 3 mol% to 30 mol%. If the content ratio is less than 2 mol%, the effects exhibited by the glutariminium unit will not be sufficiently exerted (e.g., higher optical characteristics, higher mechanical strength, and superior polarizing elements). Resistance, thinning). When the content ratio exceeds 50 mol%, for example, heat resistance and transparency may become insufficient. The acrylic resin may contain only a single (meth) acrylic acid alkyl ester unit, or may include a plurality of (meth) acrylic acid alkyl ester units having different R ⁴ and R ⁵ in the general formula (2). The content ratio of the (meth) acrylic acid alkyl ester unit in the acrylic resin is preferably 50 mol% to 98 mol%, more preferably 55 mol% to 98 mol%, and still more preferably 60 mol. Ear% ~ 98 mole%, particularly preferably 65 mole% ~ 98 mole%, and most preferably 70 mole% ~ 97 mole%. If the content ratio is less than 50 mol%, there is a possibility that the effects (for example, higher heat resistance and higher transparency) expressed by the (meth) acrylic acid alkyl ester unit may not be sufficiently exhibited. If the content ratio is more than 98 mol%, the resin may become brittle and may be easily cracked, failing to sufficiently exhibit high mechanical strength, and may be inferior in productivity. The acrylic resin may contain units other than a glutariminium unit and an alkyl (meth) acrylate unit. In one embodiment, the acrylic resin may contain an unsaturated carboxylic acid unit that does not participate in the intramolecular ammonium imidization reaction described below, for example, 0 to 10% by weight. The content ratio of the unsaturated carboxylic acid unit is preferably 0 to 5% by weight, and more preferably 0 to 1% by weight. When the content is within this range, transparency, retention stability, and moisture resistance can be maintained. In one embodiment, the acrylic resin may contain a copolymerizable vinyl monomer unit (other vinyl monomer units) other than the above. Examples of the other vinyl-based monomer include acrylonitrile, methacrylonitrile, ethacrylonitrile, allyl glycidyl ether, maleic anhydride, itaconic anhydride, and N-methyl maleic acid. Fluorenimine, N-ethylcisbutenedifluoreneimine, N-cyclohexylcisbutenedifluoreneimine, aminoethyl acrylate, propylaminoethyl acrylate, dimethylaminoethyl methacrylate Esters, ethylaminopropyl methacrylate, cyclohexylaminoethyl methacrylate, N-vinyldiethylamine, N-ethylfluorenylvinylamine, allylamine, methallyl Amine, N-methylallylamine, 2-isopropenyloxazoline, 2-vinyloxazoline, 2-propenyloxazoline, N-phenylcis butylenediimine, methylamine Phenylaminoethyl acrylate, styrene, α-methylstyrene, p-glycidylstyrene, p-aminostyrene, 2-styryloxazoline, and the like. These can be used alone or in combination. A styrene-based monomer such as styrene or α-methylstyrene is preferred. The content ratio of other vinyl-based monomer units is preferably 0 to 1% by weight, and more preferably 0 to 0.1% by weight. With such a range, it is possible to suppress the expression of an undesired phase difference and decrease in transparency. The fluorene imidation ratio in the acrylic resin is preferably 2.5% to 20.0%. If the fluorene imidization ratio is within this range, a resin excellent in heat resistance, transparency, and molding processability can be obtained, and the occurrence of scorch or reduction in mechanical strength during film formation can be prevented. In the above-mentioned acrylic resin, the fluorene imidization ratio is expressed as a ratio of a glutariminium unit to an alkyl (meth) acrylate unit. The ratio can be obtained, for example, from an NMR (nuclear magnetic resonance) spectrum of an acrylic resin, an IR (infrared) spectrum, or the like. In this embodiment, the hydrazone imidization ratio can be determined by ¹ H-NMR measurement of the resin using ¹ HNMR BRUKER Avance III (400 MHz). More specifically, the peak area of the O-CH ₃ proton derived from the alkyl (meth) acrylate in the vicinity of 3.5 to 3.8 ppm is set to A, and the glutariminium derived in the vicinity of 3.0 to 3.3 ppm is set to A. The peak area of the N-CH ₃ proton is set to B, and it is determined by the following formula.醯 Imidization ratio Im (%) = {B / (A + B)} × 100 The acid value of the acrylic resin is preferably 0.10 mmol / g to 0.50 mmol / g. When the acid value is in this range, a resin excellent in the balance of heat resistance, mechanical properties, and moldability can be obtained. If the acid value is too small, problems such as an increase in cost due to the use of a modifier for adjusting to a desired acid value, and generation of gels due to the remaining of the modifier may occur. If the acid value is too large, foaming during film formation (for example, during melt extrusion) tends to occur, and the productivity of the molded product tends to decrease. Regarding the acrylic resin, the acid value is the content of carboxylic acid units and carboxylic anhydride units in the acrylic resin. In this embodiment, the acid value can be calculated by, for example, a titration method described in WO2005 / 054311 or Japanese Patent Laid-Open No. 2005-23272. The weight average molecular weight of the acrylic resin is preferably 1,000 to 2,000,000, more preferably 5,000 to 1,000,000, still more preferably 10,000 to 500,000, particularly preferably 50,000 to 500,000, and most preferably 60,000 to 150,000. The weight-average molecular weight can be obtained, for example, by using a gel permeation chromatography (GPC system, manufactured by Tosoh) in terms of polystyrene. Furthermore, tetrahydrofuran can be used as a solvent. The Tg (glass transition temperature) of the acrylic resin is preferably 110 ° C or higher, more preferably 115 ° C or higher, even more preferably 120 ° C or higher, even more preferably 125 ° C or higher, and most preferably 130 ° C or higher. When Tg is 110 ° C or higher, a polarizing plate containing a base film obtained from such a resin is likely to be excellent in durability. The upper limit of Tg is preferably 300 ° C or lower, more preferably 290 ° C or lower, even more preferably 285 ° C or lower, particularly preferably 200 ° C or lower, and most preferably 160 ° C or lower. When Tg is in this range, the moldability is excellent. B-2-2. Polymerization of acrylic resin The acrylic resin can be produced by the following method, for example. The method includes: (I) an alkyl (meth) acrylate monomer corresponding to the alkyl (meth) acrylate unit represented by the general formula (2) and an unsaturated carboxylic acid monomer and / or Copolymerization of a precursor monomer to obtain a copolymer (a); and (II) treating the copolymer (a) with a fluorinated agent, thereby performing an alkyl (meth) acrylate in the copolymer (a) Ester monomer units and unsaturated carboxylic acid monomers and / or precursor monomer units of the intramolecular amidine imidization reaction, and the glutaridine imine unit represented by the general formula (1) is introduced into the copolymer in. Examples of the unsaturated carboxylic acid monomer include acrylic acid, methacrylic acid, butenoic acid, α-substituted acrylic acid, and α-substituted methacrylic acid. Examples of the precursor monomer include acrylamide and methacrylamide. These can be used alone or in combination. The preferred unsaturated carboxylic acid monomer is acrylic acid or methacrylic acid, and the preferred precursor monomer is acrylamide. As a method for treating the copolymer (a) with a sulfonium imidating agent, any appropriate method can be used. Specific examples include a method using an extruder and a method using a batch reaction tank (pressure vessel). The method of using an extruder includes heating and melting the copolymer (a) using an extruder, and treating the copolymer (a) with an amidine imidating agent. In this case, as the extruder, any appropriate extruder can be used. Specific examples include a uniaxial extruder, a biaxial extruder, and a multiaxial extruder. In the method using a batch type reaction tank (pressure vessel), any appropriate batch type reaction tank (pressure vessel) can be used. As the amidine imidating agent, any appropriate compound can be used as long as it can generate a glutariminium unit represented by the general formula (1). Specific examples of fluorene imidating agents include amines containing aliphatic hydrocarbon groups such as methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, tertiary butylamine, and n-hexylamine; aniline, Amine containing aromatic hydrocarbon groups such as benzylamine, toluidine and trichloroaniline; amines containing alicyclic hydrocarbon groups such as cyclohexylamine. Further, for example, a urea-based compound that generates such an amine by heating can be used. Examples of the urea compound include urea, 1,3-dimethylurea, 1,3-diethylurea, and 1,3-dipropylurea. The amidine imidating agent is preferably methylamine, ammonia, cyclohexylamine, and more preferably methylamine. In the fluorene imidization, in addition to the fluorene imidization agent described above, a ring closure accelerator may be added as necessary. The amount of the fluorene imidating agent used in the fluorene imidization is preferably 0.5 to 10 parts by weight, and more preferably 0.5 to 6 parts by weight based on 100 parts by weight of the copolymer (a). If the amount of fluorene imidating agent used is less than 0.5 parts by weight, the desired fluorination ratio of fluorene is often not achieved. As a result, the heat resistance of the obtained resin may be extremely insufficient, and appearance defects such as burnt after molding may be induced. When the amount of the fluorene imidating agent exceeds 10 parts by weight, there may be cases where the fluorene imidizing agent remains in the resin and appearance defects such as scorching after molding or foaming are induced by the fluorinating agent. The manufacturing method according to this embodiment may include a treatment with an esterifying agent, if necessary, in addition to the above-mentioned phosphonium imidization. Examples of the esterifying agent include dimethyl carbonate, 2,2-dimethoxypropane, dimethyl sulfene, triethyl orthoformate, trimethyl orthoacetate, trimethyl orthoformate, and dicarbonate. Phenyl ester, dimethyl sulfate, methyl tosylate, methyl triflate, methyl acetate, methanol, ethanol, methyl isocyanate, p-chlorophenyl isocyanate, dimethylcarbodifluoride Imine, dimethyl tert-butylsilyl chloride, isopropenyl acetate, dimethylurea, tetramethylammonium hydroxide, dimethyldiethoxysilane, tetra-n-butoxysilane, phosphorous acid Dimethyl (trimethylsilyl) ester, trimethyl phosphite, trimethyl phosphate, tricresyl phosphate, diazomethane, ethylene oxide, propylene oxide, cyclohexane, 2- Ethylhexyl glycidyl ether, phenyl glycidyl ether, benzyl glycidyl ether. Among these, dimethyl carbonate is preferable from a viewpoint of cost, reactivity, and the like. The amount of the esterifying agent to be added can be set such that the acid value of the acrylic resin becomes a desired value. B-2-3. Combination of other resins In the embodiment of the present invention, the above-mentioned acrylic resin can be used in combination with other resins. That is, the monomer components constituting the acrylic resin and the monomer components constituting other resins may be copolymerized, and the copolymer may be used for the film formation described in the item B-4 below; the acrylic resin may be copolymerized with other resins. The resin blend is used for film formation. Examples of other resins include styrenic resin, polyethylene, polypropylene, polyamine, polyphenylene sulfide, polyether ether ketone, polyester, polyfluorene, polyphenylene ether, polyacetal, and polyfluorene. Other thermoplastic resins such as amines, polyethers and imines; thermosetting resins such as phenol-based resins, melamine-based resins, polyester-based resins, polysiloxane-based resins, and epoxy-based resins. The types and blending amounts of the resins to be used in combination can be appropriately set depending on the purpose and characteristics expected from the obtained film. For example, a styrene-based resin (preferably an acrylonitrile-styrene copolymer) can be used in combination as a retardation control agent. When the acrylic resin is used in combination with other resins, the content of the acrylic resin in the blend of the acrylic resin and other resins is preferably 50% to 100% by weight, and more preferably 60% to 100% by weight. %, More preferably 70% by weight to 100% by weight, and particularly preferably 80% by weight to 100% by weight. When the content is less than 50% by weight, the high heat resistance and high transparency of the acrylic resin may not be sufficiently reflected. B-3. Core-shell particles In the above base film, the core-shell particles are 100 parts by weight relative to the acrylic resin, and the blending is preferably 5 parts by weight to 50 parts by weight, and more preferably 5 parts by weight to 40 parts. Parts by weight. This can reduce the dimensional change rate of the base film. As a result, it is possible to suppress shrinkage in a state where the surface-treated layer is formed, and to obtain an optical film having high adhesion between the substrate film and the surface-treated layer. The core-shell type particles typically have a core containing a rubbery polymer and a coating layer containing a glassy polymer and covering the core. The core-shell particles have one or more layers containing a glassy polymer as an innermost layer or an intermediate layer. The Tg of the rubber-like polymer constituting the core is preferably 20 ° C or lower, more preferably -60 ° C to 20 ° C, and even more preferably -60 ° C to 10 ° C. If the Tg of the rubber-like polymer constituting the core exceeds 20 ° C, the mechanical strength of the acrylic resin may not be sufficiently improved. The Tg of the glassy polymer (hard polymer) constituting the coating layer is preferably 50 ° C or higher, more preferably 50 ° C to 140 ° C, and still more preferably 60 ° C to 130 ° C. If the Tg of the glass-like polymer constituting the coating layer is lower than 50 ° C, the heat resistance of the acrylic resin may decrease. The content ratio of the core in the core-shell particles is preferably 30% to 95% by weight, and more preferably 50% to 90% by weight. The ratio of the glassy polymer layer in the core is 0 to 60% by weight, preferably 0 to 45% by weight, and more preferably 10% to 40% by weight relative to the total weight of the core. The content ratio of the coating layer in the core-shell particles is preferably 5 to 70% by weight, and more preferably 10 to 50% by weight. In one embodiment, the core-shell particles dispersed in the acrylic resin may have a flat shape. Core-shell particles can be flattened by the extension described in item B-4 below. The length / thickness ratio of the flattened core-shell particles is 7.0 or less. The length / thickness ratio is preferably 6.5 or less, and more preferably 6.3 or less. On the other hand, the length / thickness ratio is preferably 4.0 or more, more preferably 4.5 or more, and even more preferably 5.0 or more. In the present specification, the "length / thickness ratio" means the ratio of the length and thickness of the core-shell particle in a plan view. Here, the so-called "representative length" refers to the diameter when the plan shape is circular, the long diameter in the case of ellipse, and the diagonal length in the case of rectangle or polygon. This ratio can be obtained, for example, in the following procedure. The obtained film cross-section was photographed using a transmission electron microscope (for example, accelerated voltage 80 kV, RuO ₄ staining ultra-thin sectioning method), and the longer of the core-shell particles (obtained close to Among the sections representing length, 30 were selected in order, and the (average of length) / (average of thickness) was calculated, thereby obtaining the ratio. The details of the rubber-like polymer constituting the core of the core-shell particle, the glass-like polymer (hard polymer) constituting the coating layer, the polymerization method thereof, and other constitutions are described in, for example, Japanese Patent Laid-Open No. 2016-33552 Bulletin. The description of this gazette is incorporated by reference in this specification. B-4. Formation of the base material film The base material film according to the embodiment of the present invention may typically include the above-mentioned acrylic resin (when used in combination with other resins, it is a blend with the other resins) It is formed by a method of forming a film of the composition of core-shell particles. Furthermore, the method of forming a substrate film may include extending the film. The average particle diameter of the core-shell particles used in film formation for film formation is preferably 1 nm to 500 nm. The average particle diameter of the core is preferably 50 nm to 300 nm, and more preferably 70 nm to 300 nm. As a method of forming a film, any appropriate method can be adopted. Specific examples include a flow casting coating method (for example, a casting method), an extrusion molding method, an injection molding method, a compression molding method, a transfer molding method, a blow molding method, a powder molding method, and FRP (Fiber Reinforced Plastic (fiber-reinforced plastic) forming method, calendering method, and hot pressing method. An extrusion molding method or a flow casting coating method is preferred. The reason is that the smoothness of the obtained film can be improved, and good optical uniformity can be obtained. Particularly preferred is extrusion molding. The reason is that there is no need to consider the problems caused by the residual solvent. Among them, an extrusion molding method using a T-die is preferable from the viewpoints of productivity of the film and ease of subsequent stretching treatment. The molding conditions can be appropriately set according to the composition or type of the resin to be used, the characteristics expected for the obtained film, and the like. As the stretching method, any appropriate stretching method and stretching conditions (for example, stretching temperature, stretching magnification, stretching speed, stretching direction) can be adopted. Specific examples of the extension method include free end extension, fixed end extension, free end contraction, and fixed end contraction. These can be used singly, simultaneously, or sequentially. By extending the film whose core-shell type particles have been appropriately adjusted with respect to the acrylic resin under appropriate stretching conditions, the dimensional change rate of the obtained base film can be reduced. As a result, it is possible to suppress shrinkage in a state where the surface-treated layer is formed, and to obtain an optical film having high adhesion between the substrate film and the surface-treated layer. The direction of extension can be adapted to the purpose. Specific examples include a length direction, a width direction, a thickness direction, and an oblique direction. The extending direction may be one direction (uniaxial extension), two directions (biaxial extension), or three or more directions. In the embodiment of the present invention, typically, uniaxial extension in the longitudinal direction, simultaneous biaxial extension in the longitudinal direction and the width direction, and sequential biaxial extension in the longitudinal direction and the width direction may be adopted. Biaxial extension (simultaneous or sequential) is preferred. The reason is that it is easy to control the in-plane phase difference, and it is easy to achieve optical isotropy. The stretching temperature can be based on the optical characteristics, mechanical characteristics and thickness expected for the substrate film, the type of resin used, the thickness of the film used, the stretching method (uniaxial or biaxial stretching), the stretching ratio, and the stretching speed. And so on. Specifically, the extension temperature is preferably Tg ~ Tg + 50 ° C, more preferably Tg + 15 ° C ~ Tg + 50 ° C, and most preferably Tg + 35 ° C ~ Tg + 50 ° C. By stretching at such a temperature, a substrate film having suitable characteristics can be obtained. The specific extension temperature is, for example, 110 ° C to 200 ° C, preferably 120 ° C to 190 ° C, and further preferably 150 ° C to 190 ° C. If the elongation temperature is in this range, by appropriately adjusting the elongation ratio and elongation speed, the film having the adjusted amount of the shell particles appropriately adjusted can be extended under the appropriate elongation conditions, thereby reducing the obtained base film. Dimensional change rate. As a result, it is possible to suppress shrinkage in a state where the surface-treated layer is formed, and to obtain an optical film having high adhesion between the substrate film and the surface-treated layer. In addition, the stretching ratio can be the same as the stretching temperature according to the optical characteristics, mechanical characteristics and thickness, the type of resin used, the thickness of the film used, the stretching method (uniaxial stretching or biaxial stretching), the stretching temperature, and the stretching. Speed and so on. In the case of biaxial extension, the ratio of the extension ratio in the width direction (TD) to the extension ratio in the length direction (MD) (TD / MD) is preferably 1.0 to 1.5, more preferably 1.0 to 1.4, and more preferably It is 1.0 ~ 1.3. In addition, the area magnification (product of the extension magnification in the longitudinal direction and the extension magnification in the width direction) when the biaxial stretching is used is preferably 2.0 to 6.0, more preferably 3.0 to 5.5, and even more preferably 3.5 to 5.2. If the stretching ratio is in this range, the dimensional change rate of the obtained base film can be reduced by appropriately adjusting the stretching temperature and the stretching speed. As a result, it is possible to suppress shrinkage in a state where the surface-treated layer is formed, and to obtain an optical film having high adhesion between the substrate film and the surface-treated layer. In addition, the extension speed may be the same as the extension temperature according to the optical characteristics, mechanical characteristics and thickness, the type of resin used, the thickness of the film used, the extension method (uniaxial or biaxial extension), the extension temperature, and the extension. The magnification changes. The extension speed is preferably 3% / second to 20% / second, more preferably 3% / second to 15% / second, and even more preferably 3% / second to 10% / second. In the case of biaxial extension, the extension speed in one direction and the extension speed in the other direction may be the same or different. If the stretching speed is in this range, the dimensional change rate of the obtained base film can be reduced by appropriately adjusting the stretching temperature and the stretching ratio. As a result, it is possible to suppress shrinkage in a state where the surface-treated layer is formed, and to obtain an optical film having high adhesion between the substrate film and the surface-treated layer. A substrate film can be formed in the above-mentioned manner. C. Surface treatment layer The surface treatment layer is any appropriate functional layer formed on one side of the substrate film according to the function required for the optical film. Specific examples of the surface treatment layer include a hard coat layer, an anti-glare layer, and an anti-reflection layer. The thickness of the surface treatment layer is preferably 3 μm to 20 μm, and more preferably 5 μm to 15 μm. The surface treatment layer is typically a hardened layer of a resin composition formed on a base film. The step of forming the surface treatment layer may include: applying a resin composition for forming a surface treatment layer on a substrate film to form a coating layer; and drying and curing the coating layer to form a surface treatment layer. Drying and curing the coating layer may include heating the coating layer. As a coating method of the resin composition, any appropriate method can be adopted. Examples include: bar coating method, roll coating method, gravure coating method, rod coating method, slot coating method, curtain coating method, spray coating method, notch Wheel coating method. From the viewpoint of facilitating application, the resin composition preferably contains a solvent for dilution. The heating temperature of the coating layer can be set to any appropriate temperature corresponding to the composition of the resin composition, and is preferably set to be equal to or lower than the glass transition temperature of the acrylic resin contained in the base film. When the heating is performed at a temperature lower than the glass transition temperature of the acrylic resin contained in the base film, an optical film in which deformation due to heating is suppressed can be obtained. The heating temperature of the coating layer is, for example, 50 ° C to 140 ° C, and preferably 60 ° C to 100 ° C. By heating at such a heating temperature, an optical film having excellent adhesion between the substrate film and the surface treatment layer can be obtained. C-1. Hard coat layer A hard coat layer is a layer which imparts scratch resistance and chemical resistance to the surface of a base film. The hard coat layer has a hardness of preferably H or more, and more preferably 3H or more in a pencil hardness test. The pencil hardness test can be measured in accordance with JIS K 5400. The resin composition for forming a hard coat layer may contain, for example, a hardening compound that can be hardened by heat, light (such as ultraviolet rays), or an electron beam. The details of the hard coat layer and the resin composition for forming the hard coat layer are described in, for example, Japanese Patent Laid-Open No. 2014-240955. The entire description of this publication is incorporated herein by reference. C-2. Anti-glare layer The anti-glare layer is a layer for preventing the reflection of external light by scattering and reflecting light. The resin composition for forming the anti-glare layer may contain, for example, a curable compound that can be cured by heat, light (such as ultraviolet rays), or an electron beam. The anti-glare layer typically has a fine uneven shape on the surface. As a method of forming such a fine uneven | corrugated shape, the method of making microparticles | fine-particles containing the said hardening compound is mentioned, for example. The details of the anti-glare layer and the resin composition for forming the anti-glare layer are described in, for example, Japanese Patent Laid-Open No. 2017-32711. The entire description of this publication is incorporated herein by reference. C-3. Anti-reflection layer The anti-reflection layer is a layer used to prevent reflection of external light. The resin composition for forming an antireflection layer may contain, for example, a hardening compound capable of being hardened by heat, light (such as ultraviolet rays), or an electron beam. The antireflection layer may be a single layer composed of only one layer, or a plurality of layers including two or more layers. The details of the antireflection layer and the resin composition for forming the antireflection layer are described in, for example, Japanese Patent Laid-Open No. 2012-155050. The entire description of this publication is incorporated herein by reference. D. Polarizing plate The optical film described in the above items A to C can be applied to a polarizing plate. Therefore, the present invention also includes a polarizing plate using such an optical film. Typically, a polarizing plate has a polarizing element and the optical film of this invention arrange | positioned on one side of a polarizing element. For an optical film, the base film side can be bonded to a polarizing element, and can function as a protective layer of the polarizing element. As the polarizing element, any suitable polarizing element can be used. For example, the resin film forming the polarizing element may be a single-layer resin film or a laminated body of two or more layers. Specific examples of the polarizing element including a single-layer resin film include hydrophilic polymers such as polyvinyl alcohol (PVA) -based films, partially formalized PVA-based films, and ethylene-vinyl acetate copolymer-based partially saponified films. The film is made by dyeing and extending treatment of a dichroic substance such as iodine or a dichroic dye; a polyene-based alignment film such as a dehydrated product of PVA or a dehydrochlorinated product of polyvinyl chloride. In terms of excellent optical characteristics, it is preferable to use a polarizing element obtained by dyeing a PVA-based film with iodine and uniaxially stretching it. The dyeing using iodine is performed, for example, by immersing a PVA-based film in an iodine aqueous solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the dyeing treatment, or may be performed while dyeing. It is also possible to perform dyeing after stretching. The PVA-based film is subjected to a swelling treatment, a crosslinking treatment, a washing treatment, a drying treatment, and the like, as necessary. For example, by immersing the PVA-based film in water and washing with water before dyeing, not only the dirt or anti-blocking agent on the surface of the PVA-based film can be cleaned, but also the PVA-based film can be swelled to prevent uneven dyeing. Specific examples of the polarizing element obtained by using a laminate include a laminate using a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a resin substrate and coating formed on A polarizing element obtained by laminating a PVA-based resin layer of the resin substrate. A polarizing element obtained by using a laminate of a resin substrate and a PVA-based resin layer formed on the resin substrate can be produced, for example, by applying a PVA-based resin solution to the resin substrate, drying it, and A PVA-based resin layer is formed on the resin substrate to obtain a laminated body of the resin substrate and the PVA-based resin layer; the laminated body is extended and dyed to form a PVA-based resin layer as a polarizing element. In this embodiment, stretching typically includes immersing a laminate in a boric acid aqueous solution to perform stretching. Further, if necessary, the stretching may further include performing air stretching at a high temperature (for example, 95 ° C. or higher) on the laminate before stretching in a boric acid aqueous solution. The obtained resin substrate / polarizing element laminated body can be used directly (that is, the resin substrate can be used as a protective layer of the polarizing element), or the resin substrate can be peeled from the resin substrate / polarizing element laminated body, Any appropriate protective layer suitable for the purpose of the peeling area layer is used. The details of the method of manufacturing such a polarizing element are described in, for example, Japanese Patent Laid-Open No. 2012-73580. The entire description of this publication is incorporated herein by reference. The thickness of the polarizing element is, for example, 1 μm to 80 μm. In one embodiment, the thickness of the polarizing element is preferably 1 μm to 20 μm, and more preferably 3 μm to 15 μm. E. Image display device The polarizing plate described in item D above can be applied to an image display device. Therefore, the present invention also includes an image display device using such a polarizing plate. Typical examples of the image display device include a liquid crystal display device and an organic electroluminescence (EL) display device. The image display device adopts a well-known configuration in the industry, and therefore detailed descriptions thereof are omitted. Examples Hereinafter, the present invention will be specifically described by examples, but the present invention is not limited to these examples. The measurement method of each characteristic is as follows. It should be noted that "parts" and "%" in the examples are based on weight unless otherwise specifically described. (1) Dimensional change rate of the base film The base film was cut into 10 cm × 10 cm along its long side direction and short side direction to prepare a measurement sample. The above measurement sample was bonded to a glass plate via an adhesive material, and allowed to stand in an environmental testing machine at 100 ° C. for 120 hours. The dimensional change rate of the substrate film was measured using QVA606-PRO-AE10 manufactured by Mitutoyo. The adhesion of the measurement sample to the glass plate was performed using an adhesive containing 95 parts of butyl acrylate, 5 parts of acrylic acid, 0.1 part of 2-hydroxyethyl acrylate, and 0.05 parts of 2-2 azobisisobutyronitrile. In addition, the dimensional change rate is a dimensional measurement of a measurement sample placed on the environmental testing machine in a direction parallel to the cutting surface (each side of the measurement sample) at a position 1 cm away from the end, using the following formula Calculate the dimensional change rate. The dimensional change rate in the direction corresponding to the long-side direction of the base film and the dimensional change rate in the direction corresponding to the short-side direction were measured. Dimensional change rate (%) = (size after 120 hours at 100 ° C-initial size) / initial size × 100 (2) Adhesion evaluation Grid peel test (number of grids: 100) according to JIS K-5400 The surface treatment layer evaluated the adhesiveness of the base film, and judged by the following indicators. : The number of grid peeling is 0 Δ: The number of grid peeling is 1 or more and less than 10 ×: The number of grid peeling is 10 or more <Manufacturing Example 1> The following compositions A to C were prepared as surface treatment layers Forming resin composition. (1) Composition A: 16 parts by weight of 4-HBA (4-hydroxybutyl acrylate) (manufactured by Osaka Organic Chemical Industry Co., Ltd.), NK oligomer UA-53H-80BK (Shinakamura Chemical Industry) Co., Ltd.) 32 parts by weight, Viscoat # 300 (manufactured by Osaka Organic Chemical Industry Co., Ltd.) 48 parts by weight, A-GLY-9E (manufactured by Shin Nakamura Chemical Industry Co., Ltd.) 4 parts by weight, and IRGACURE 907 (BASF (Production) 2.4 parts by weight are mixed, and the concentration of the solid content is 42.0% by using a solvent of MIBK (methyl isobutyl ketone, methyl isobutyl ketone): PGM (Propylene glycol monomethylether, propylene glycol monomethyl ether) = 50:50. The UV curable resin obtained by diluting it in this manner. (2) Composition B 100 parts by weight of Viscoat # 300 (manufactured by Osaka Organic Chemical Industry Co., Ltd.) and 2.4 parts by weight of IRGACURE 907 (manufactured by BASF) were mixed, and solids were formed with a solvent of MIBK: PGM = 50: 50 A UV-curable resin obtained by diluting so that the component concentration becomes 42.0%. (3) Composition C 4-HBA (manufactured by Osaka Organic Chemical Industry Co., Ltd.) 20 parts by weight, NK oligomeric UA-53H-80BK (made by Shin Nakamura Chemical Industry Co., Ltd.) 40 parts by weight, Viscoat # 300 (Osaka Organic Chemical Industry Co., Ltd.) 60 parts by weight, IRGACURE 907 (manufactured by BASF) 5 parts by weight, and 0.5 parts by weight of Techpolymer SSX-103DXE (manufactured by Sekisui Chemical Industry Co., Ltd.) were mixed, and toluene: MEK ( methyl ethyl ketone) = 70: 30 A UV curable resin obtained by diluting a solvent with a solid content concentration of 40.0%. 〈Example 1〉 1. Production of a base film. Monomethylamine was used to copolymerize MS resin (MS-200; methyl methacrylate / styrene (Molar ratio) = 80/20). Material, manufactured by Nippon Steel Chemical Co., Ltd.), to perform amidation (amidation ratio: 5%). The obtained amidine imidized MS resin has a glutarimide unit (R ¹ and R ³ are methyl groups, and R ² is a hydrogen atom) represented by the general formula (1), and ( Meth) acrylate units (R ⁴ and R ⁵ are methyl groups), and styrene units. In addition, the above sulfonium imidization uses a co-rotating co-rotating biaxial extruder with a mesh diameter of 15 mm. The setting temperature of each temperature adjustment zone of the extruder was set to 230 ° C, the screw rotation speed was set to 150 rpm, and the MS resin was supplied at 2.0 kg / hr. The supply amount of the monomethylamine was 100 parts by weight with respect to the MS resin. It is set to 2 parts by weight. MS resin was charged from a hopper, and the resin was melted and filled by a kneading section, and then monomethylamine was injected from a nozzle. Fill the end of the reaction zone with a sealing ring to fill the resin. The pressure at the exhaust port was reduced to -0.08 MPa to remove by-products and excess methylamine after the reaction. The resin discharged from the die set at the exit of the extruder in the form of strands is cooled in a water tank, and then granulated by a pelletizer. The obtained amidine imidized MS resin had a amidine imidization rate of 5.0% and an acid value of 0.5 mmol / g. 100 parts by weight of the fluorene imidized MS resin obtained above and 10 parts by weight of the core-shell particles were put into a uniaxial extruder and melt-mixed to form a film through a T die, thereby obtaining an extruded film. The obtained extruded film was simultaneously biaxially stretched twice in the length direction and the width direction at an extension temperature of 160 ° C. The extension speed is 10% / second in both the length and width directions. Thus, a base film A was produced. The thickness of the obtained base film A was 40 μm. The dimensional change rate in the long-side direction and the dimensional change rate in the short-side direction of the base film A were measured. The results are shown in Table 1. 2. Production of Optical Film The composition A was coated on one side of the substrate film A so that the thickness after curing became 6 μm to form a coating layer. Then, the coating layer was dried at 70 ° C. and subjected to UV curing, thereby obtaining an optical film 1 having a hard coat layer formed on one side of the base film A. The optical film 1 was subjected to adhesion evaluation. The results are shown in Table 1. <Example 2> 1. Production of a base film 100 parts by weight of the obtained fluorinated MS resin and 10 parts by weight of core-shell particles were put into a uniaxial extruder for melt mixing, and passed through a T die. Film formation was performed, whereby an extruded film was obtained. The obtained extruded film was simultaneously biaxially stretched twice in the length direction and the width direction at an extension temperature of 160 ° C. The extension speed is 10% / second in both the length and width directions. Thus, a base film B was produced. The thickness of the obtained base film B was 35 μm. The dimensional change rate in the long-side direction and the dimensional change rate in the short-side direction of the base film B were measured. The results are shown in Table 1. 2. Production of Optical Film An optical film 2 having a hard coat layer formed on one side of the base film B was obtained in the same manner as in Example 1 except that the base film B was used. The optical film 2 was subjected to adhesion evaluation. The results are shown in Table 1. <Example 3> 1. Production of substrate film The obtained fluorene imidized MS resin was put into a uniaxial extruder and melt-mixed, and a film was formed by a T die to obtain an extruded film. The obtained extruded film was simultaneously biaxially stretched twice in the length direction and the width direction at an extension temperature of 160 ° C. The extension speed is 10% / second in both the length and width directions. Thus, a base film C was produced. The thickness of the obtained base film C was 30 μm. The dimensional change rate in the long-side direction and the dimensional change rate in the short-side direction of the base film C were measured. The results are shown in Table 1. 2. Production of Optical Film An optical film 3 having a hard coat layer formed on one side of the base film C was obtained in the same manner as in Example 1 except that the base film C was used. The optical film 3 was subjected to adhesion evaluation. The results are shown in Table 1. <Example 4> 1. Production of base film The base film D was produced in the same manner as in Example 3 except that the blending amount of the core-shell particles was set to 10 parts by weight. The dimensional change rate in the long-side direction and the dimensional change rate in the short-side direction of the base film D were measured. The results are shown in Table 1. 2. Production of Optical Film An optical film 4 having a hard coat layer formed on one side of the base film D was obtained in the same manner as in Example 1 except that the base film D was used. The optical film 4 was subjected to adhesion evaluation. The results are shown in Table 1. <Example 5> The substrate B was coated in the same manner as in Example 4 except that the composition B was coated on one side of the substrate film D and cured by drying to form a hard coat layer. An optical film 5 having a hard coat layer formed on one side of D. The above-mentioned optical film 5 was subjected to adhesion evaluation. The results are shown in Table 1. <Example 6> Except that the composition C was coated on one side of the substrate film D and cured to form an anti-glare layer, the same procedure as in Example 4 was performed to obtain a unit of the substrate film D. An optical film 6 is formed on the side with an anti-glare layer. The optical film 6 was subjected to adhesion evaluation. The results are shown in Table 1. <Example 7> 1. Preparation of base material film The same as Example 3 was used except that the blending amount of the core-shell particles was set to 10 parts by weight and the extension temperature of the extruded film was set to 150 ° C. A substrate film E was produced. The dimensional change rate in the long-side direction and the dimensional change rate in the short-side direction of the base film E were measured. The results are shown in Table 1. 2. Production of Optical Film An optical film 7 having a hard coat layer formed on one side of the base film E was obtained in the same manner as in Example 1 except that the base film E was used. The optical film 7 was subjected to adhesion evaluation. The results are shown in Table 1. <Example 8> 1. Production of a base film The same as Example 3 was performed except that the blending amount of the core-shell particles was set to 15 parts by weight, and the extension temperature of the extruded film was set to 152 ° C. A substrate film F was produced. The dimensional change rate in the long-side direction and the dimensional change rate in the short-side direction of the base film F were measured. The results are shown in Table 1. 2. Production of Optical Film An optical film 8 having a hard coat layer formed on one side of the base film F was obtained in the same manner as in Example 1 except that the base film F was used. The optical film 8 was subjected to adhesion evaluation. The results are shown in Table 1. <Example 9> 1. Production of base film The base film G was produced in the same manner as in Example 3 except that the extension temperature of the extruded film was set to 155 ° C. The dimensional change rate in the long-side direction and the dimensional change rate in the short-side direction of the base film G were measured. The results are shown in Table 1. 2. Production of Optical Film An optical film 9 having a hard coat layer formed on one side of the base film G was obtained in the same manner as in Example 1 except that the base film G was used. The optical film 9 was subjected to adhesion evaluation. The results are shown in Table 1. <Example 10> 1. Production of a base film The same as Example 3 was performed except that the blending amount of the core-shell particles was set to 10 parts by weight and the extension temperature of the extruded film was set to 140 ° C. Method to produce a base film H. The dimensional change rate in the long-side direction and the dimensional change rate in the short-side direction of the base film H were measured. The results are shown in Table 1. 2. Production of Optical Film An optical film 10 having a hard coat layer formed on one side of the base film H was obtained in the same manner as in Example 1 except that the base film H was used. The optical film 10 was subjected to adhesion evaluation. The results are shown in Table 1. <Example 11> 1. Production of base film The same as Example 3 except that the blending amount of the core-shell particles was 23 parts by weight and the extension temperature of the extruded film was 152 ° C. Method to produce a base film I. The dimensional change rate in the long-side direction and the dimensional change rate in the short-side direction of the substrate film I were measured. The results are shown in Table 1. 2. Production of Optical Film An optical film 11 having a hard coat layer formed on one side of the substrate film I was obtained in the same manner as in Example 1 except that the above-mentioned substrate film I was used. The optical film 11 was subjected to adhesion evaluation. The results are shown in Table 1. <Example 12> 1. Production of a base film The same as Example 3 was performed except that the blending amount of the core-shell particles was set to 5 parts by weight, and the extension temperature of the extruded film was set to 140 ° C. Method to produce a base film J. The dimensional change rate in the long-side direction and the dimensional change rate in the short-side direction of the base film J were measured. The results are shown in Table 1. 2. Production of Optical Film An optical film 12 having a hard coat layer formed on one side of the base film J was obtained in the same manner as in Example 1 except that the base film J was used. The optical film 12 was subjected to adhesion evaluation. The results are shown in Table 1. <Example 13> 1. Production of base film The same as Example 3 except that the blending amount of the core-shell particles was set to 23 parts by weight and the extension temperature of the extruded film was set to 140 ° C. Method to produce a base film K. The dimensional change rate in the long-side direction and the dimensional change rate in the short-side direction of the base film K were measured. The results are shown in Table 1. 2. Production of Optical Film An optical film 13 having a hard coat layer formed on one side of the base film K was obtained in the same manner as in Example 1 except that the base film K was used. The optical film 13 was subjected to adhesion evaluation. The results are shown in Table 1. <Example 14> 1. Production of base film The base film L was produced in the same manner as in Example 3 except that the extension temperature of the extruded film was set to 150 ° C. The dimensional change rate in the long-side direction and the dimensional change rate in the short-side direction of the base film L were measured. The results are shown in Table 1. 2. Production of Optical Film An optical film 14 having a hard coat layer formed on one side of the base film L was obtained in the same manner as in Example 1 except that the base film L was used. The optical film 14 was subjected to adhesion evaluation. The results are shown in Table 1. <Comparative Example 1> 1. Production of base film The base film M was produced in the same manner as in Example 3 except that the extension temperature of the extruded film was set to 130 ° C. The dimensional change rate in the long-side direction and the dimensional change rate in the short-side direction of the base film M were measured. The results are shown in Table 1. 2. Production of Optical Film An optical film 15 having a hard coat layer formed on one side of the base film M was obtained in the same manner as in Example 1 except that the base film M was used. The optical film 15 was subjected to adhesion evaluation. The results are shown in Table 1. <Comparative Example 2> 1. Production of base film The base film N was produced in the same manner as in Example 3 except that the extension temperature of the extruded film was set to 140 ° C. The dimensional change rate in the long-side direction and the dimensional change rate in the short-side direction of the base film N were measured. The results are shown in Table 1. 2. Production of Optical Film An optical film 16 having a hard coat layer formed on one side of the base film N was obtained in the same manner as in Example 1 except that the base film N was used. The optical film 16 was subjected to adhesion evaluation. The results are shown in Table 1. <Comparative Example 3> The same method as in Comparative Example 2 was used to obtain a base film except that the composition B was coated on one side of the base film N and dried to be cured. An optical film 17 having a hard coat layer is formed on one side of N. The optical film 17 was subjected to adhesion evaluation. The results are shown in Table 1. <Comparative Example 4> An anti-glare layer was obtained in the same manner as in Comparative Example 2 except that the composition C was coated on one side of the substrate film N and dried to harden it, thereby forming an anti-glare layer. An optical film 18 having an anti-glare layer is formed on one side of N. The optical film 18 was subjected to adhesion evaluation. The results are shown in Table 1. <Comparative example 5> 1. Production of base film The same as Example 3 was performed except that the blending amount of the core-shell particles was set to 3 parts by weight and the extension temperature of the extruded film was set to 140 ° C. Method to produce a substrate film O. The dimensional change rate in the long-side direction and the dimensional change rate in the short-side direction of the substrate film O were measured. The results are shown in Table 1. 2. Production of Optical Film An optical film 19 having a hard coat layer formed on one side of the base film O was obtained in the same manner as in Example 1 except that the base film O was used. The optical film 19 was subjected to adhesion evaluation. The results are shown in Table 1. [Table 1] According to Table 1, it can be seen that the surface treatment layer to the substrate film in the optical films of Examples 1 to 14 using the substrate film having the dimensional change rate in the long direction and the dimensional change rate in the short direction is -2.0% to 0% High tightness. [Industrial Applicability] The optical film of the present invention can be suitably used as a protective layer of a polarizing element. The polarizing plate having the optical film of the present invention as a protective layer can be suitably used for an image display device. The image display device described above can be used in: portable information terminals (PDA, portable information terminal), smart phones, mobile phones, clocks, digital cameras, portable game consoles and other portable devices; computer monitors, notebook computers OA equipment such as cameras and photocopiers; household electrical equipment such as camcorders, televisions, and microwave ovens; on-board equipment such as rear monitors, monitors for car navigation systems, and car stereos; digital signage, commercial store information displays Equipment; Security equipment such as surveillance monitors; Nursing monitors such as nursing monitors and medical monitors; medical equipment;

10‧‧‧ substrate film

20‧‧‧ surface treatment layer

100‧‧‧ Optical Film

FIG. 1 is a schematic cross-sectional view of an optical film according to an embodiment of the present invention.

Claims (8)

An optical film comprising a base film as an extension film containing an acrylic resin and a surface treatment layer formed on one side of the base film, and the base film in the optical film is cut to 10 at The dimensional change rate of cm × 10 cm when the glass sheet is stuck to the glass plate at 100 ° C. for 120 hours under the condition of an adhesive material is -2.0% ~ 0%. The optical film according to claim 1, wherein the base film contains the acrylic resin and core-shell particles dispersed in the acrylic resin. The optical film according to claim 2, wherein the base film contains 5 to 50 parts by weight of the core-shell particles relative to 100 parts by weight of the acrylic resin. The optical film according to any one of claims 1 to 3, wherein the acrylic resin has a material selected from the group consisting of a glutarimide unit, a lactone ring unit, a maleic anhydride unit, a maleimide unit, and At least one of the group consisting of glutaric anhydride units. The optical film according to any one of claims 1 to 4, wherein the surface treatment layer is a hardened layer of a resin coated on the substrate film. The optical film according to any one of claims 1 to 5, wherein the surface treatment layer is at least one selected from the group consisting of a hard coat layer, an anti-glare layer, and an anti-reflection layer. A polarizing plate includes a polarizing element and a protective layer disposed on one side of the polarizing element, and the protective layer is an optical film according to any one of claims 1 to 6. An image display device includes a polarizing plate as in claim 7.