JP2018109660A - Acrylic resin film and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acrylic resin film having a hard coat layer having a high scratch prevention effect. An acrylic resin film having a hard coat layer laminated on one side, the copolymer (A) containing an acrylic monomer unit and an aromatic vinyl monomer unit, and an acrylic monomer unit. An acrylic resin film comprising a polymer (B) containing no aromatic vinyl monomer unit and having a melt mass flow rate of 4.0 g / 10 minutes or less. [Selection diagram] None

Description

  The present invention relates to an acrylic resin film and a method for producing the same. Moreover, this invention relates also to the polarizer protective film which consists of the said acrylic resin film, and a polarizing plate containing the same.

  As an optical film that constitutes an image display device such as a liquid crystal display device, a polarizer protective film that is laminated and bonded to one or both sides of a polarizer is widely used in order to protect the polarizer. As such a polarizer protective film, for example, Patent Document 1 discloses a resin film containing an acrylic resin containing the following copolymer (A).

Special table 2012-504783 gazette

  In a polarizing plate composed of a polarizer and a polarizer protective film laminated on one or both sides thereof, a hard coat layer is provided on the surface opposite to the polarizer of the polarizer protective film that is the outermost layer. Thereby, the damage preventing effect on the polarizing plate surface can be enhanced. However, when a hard coat layer is provided on a polarizer protective film made of a conventional resin film containing the following copolymer (A), the hardness of the obtained hard coat layer may not always be sufficient.

  Therefore, an object of this invention is to provide the acrylic resin film which has a hard-coat layer with a high damage prevention effect. Another object of the present invention is to provide a method for producing an acrylic resin film having a hard coat layer having a high effect of preventing scratches.

The present invention provides the following preferred embodiments.
[1] An acrylic resin film having a hard coat layer laminated on one side, the following copolymer (A) and polymer (B), and having a melt mass flow rate of 4.0 g / 10 min or less An acrylic resin film composed of an acrylic resin composition.
Copolymer (A): Polymer containing acrylic monomer units and aromatic vinyl monomer units Polymer (B): Containing acrylic monomer units and no aromatic vinyl monomer units Polymer [2] The acrylic resin composition comprises 0-30% by mass of rubber elastic body particles having an average particle diameter of 10 nm to 350 nm, based on the total mass of the acrylic resin composition, [1] The acrylic resin film described in 1.
[3] A polarizer protective film comprising the acrylic resin film according to [1] or [2].
[4] Polarized light in which a polarizer is laminated via a pressure-sensitive adhesive layer or an adhesive layer on the surface opposite to the hard coat layer of the acrylic resin film according to any one of [1] to [3]. Board.
[5] A step of applying a hard coat liquid containing a solvent to one side of the acrylic resin film,
The manufacturing method of the acrylic resin film in any one of said [1]-[4] including the process of drying the hard-coat liquid after coating, and the process of hardening the hard-coat liquid after drying.

  ADVANTAGE OF THE INVENTION According to this invention, the acrylic resin film which has a hard-coat layer with a high damage prevention effect can be provided. Moreover, this invention can also provide the manufacturing method of the acrylic resin film which has a hard-coat layer with a high damage prevention effect. In particular, according to the method of the present invention, a hard coat layer having an appropriate hardness can be formed even on a relatively soft acrylic resin film surface.

It is a schematic explanatory drawing which shows the manufacturing method of the resin film of this invention.

  Hereinafter, embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiment described here, and various modifications can be made without departing from the spirit of the present invention.

  The acrylic resin film of the present invention includes a copolymer (A) containing an acrylic monomer unit and an aromatic vinyl monomer unit, an acrylic monomer unit, and an aromatic vinyl monomer unit. It is comprised from the acrylic resin composition which contains a polymer (B) which is not.

[Acrylic resin composition]
The acrylic resin composition of the present invention comprises a copolymer (A) containing an acrylic monomer unit and an aromatic vinyl monomer unit.

<Copolymer (A)>
In the present invention, the acrylic monomer unit constituting the copolymer (A) is a monomer unit derived from methacrylic acid, acrylic acid, a methacrylic ester monomer or an acrylate monomer.
Examples of the methacrylic acid ester monomer include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, Examples thereof include C1-C8 alkyl or cycloalkyl ester monomers of methacrylic acid such as cyclohexyl methacrylate. Two or more methacrylate monomers may be used in combination. Especially, the C1-C7 alkylester monomer of methacrylic acid is preferable, and methyl methacrylate is more preferable at the point of the heat resistance of an acrylic resin composition and transparency.
Examples of the acrylate monomer include, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, Examples thereof include alkyl or cycloalkyl ester monomers having 1 to 8 carbon atoms of acrylic acid such as cyclohexyl acrylate. Two or more acrylate monomers may be used in combination. Especially, the C1-C7 alkylester monomer of acrylic acid is preferable, and methyl acrylate is more preferable at the heat resistance of an acrylic resin composition and the point of transparency.

  The content of the acrylic monomer unit in the copolymer (A) is preferably 5 to 40% by mass, more preferably 100% by mass of all monomer units constituting the copolymer (A). Is 5 to 35% by mass, more preferably 5 to 30% by mass, and particularly preferably 5 to 25% by mass. In the present invention, when the acrylic resin composition contains a copolymer (A) containing an acrylic monomer unit in an amount within the above range, the heat resistance of the acrylic resin film obtained from the resin composition is improved. Can be improved.

（式中、Ｒ^３およびＲ^４は、それぞれ独立して、水素原子、ハロゲン原子、ヒドロキシル基、アルコキシ基、ニトロ基または炭素数１〜１２のアルキル基を表し、ｎは１〜３の整数を表す。）
で表される単量体単位が挙げられる。 In the present invention, the aromatic vinyl monomer unit constituting the copolymer (A) is a monomer unit derived from an aromatic vinyl monomer. In the present specification, the aromatic vinyl monomer means a monomer having a structure in which an unsubstituted vinyl group or a substituted vinyl group is bonded to an aromatic ring.
Specific examples of the aromatic vinyl monomer unit include the following formula (1):

(Wherein R ³ and R ⁴ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkoxy group, a nitro group or an alkyl group having 1 to 12 carbon atoms, and n represents an integer of 1 to 3) Represents.)
The monomer unit represented by these is mentioned.

  As a halogen atom in Formula (1), a fluorine atom, a chlorine atom, and a bromine atom are mentioned, for example. Examples of the alkyl group having 1 to 12 carbon atoms include straight chain such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, and 2-ethylhexyl group. A branched alkyl group is exemplified, an alkyl group having 1 to 8 carbon atoms is preferable, an alkyl group having 1 to 4 carbon atoms is more preferable, and a methyl group is further preferable.

R ³ is preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms (particularly an alkyl group having 1 to 8 carbon atoms, especially an alkyl group having 1 to 4 carbon atoms), more preferably a hydrogen atom or a methyl group. R ⁴ is preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms (particularly an alkyl group having 1 to 8 carbon atoms, especially an alkyl group having 1 to 4 carbon atoms), more preferably a hydrogen atom. n is preferably 1. R ³ and R ⁴ may be the same as or different from each other.

  Specific examples of the aromatic vinyl monomer include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, and 2-methyl-4. -Chlorostyrene, 2,4,6-trimethylstyrene, α-methylstyrene, cis-β-methylstyrene, trans-β-methylstyrene, 4-methyl-α-methylstyrene, 4-fluoro-α-methylstyrene, 4-chloro-α-methylstyrene, 4-bromo-α-methylstyrene, 4-tert-butylstyrene, 2-fluorostyrene, 3-fluorostyrene, 4-fluorostyrene, 2,4-difluorostyrene, 2-chloro Styrene, 3-chlorostyrene, 4-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene Down, 2-bromostyrene, 3-bromostyrene, 4-bromostyrene, 2,4-dibromostyrene, alpha-bromostyrene, beta-bromostyrene, 2-hydroxystyrene and 4-hydroxy styrene. Of these, styrene and α-methylstyrene are preferable. Two or more aromatic vinyl monomers may be used in combination.

  The content of the aromatic vinyl monomer unit in the copolymer (A) is preferably 50% by mass or more with respect to 100% by mass of all the monomer units constituting the copolymer (A). In the present invention, when the acrylic resin composition contains a copolymer (A) containing an aromatic vinyl monomer unit in an amount equal to or more than the lower limit, the acrylic resin film obtained from the resin composition is hard. When the coat layer is provided, a hard coat layer having sufficient hardness can be formed, and an acrylic resin film having a high scratch prevention effect can be obtained. Content of the aromatic vinyl monomer unit in a polymer (A) becomes like this. Preferably it is 50-80 mass%, More preferably, it is 52-78 mass%, More preferably, it is 55-75 mass%. When the content of the aromatic vinyl monomer unit in the copolymer (A) is within the above range, the resulting resin film has a high scratch-preventing effect, and has transparency, heat resistance and dimensions in a high temperature environment. Excellent stability.

  In the present invention, the copolymer (A) contained in the acrylic resin composition may contain a cyclic acid anhydride monomer unit in addition to the acrylic monomer unit and the aromatic vinyl monomer unit. preferable. When the copolymer (A) contains a cyclic acid anhydride monomer unit, the heat resistance can be improved.

（式中、Ｒ^１およびＲ^２は、それぞれ独立して、水素原子、ハロゲン原子、炭素数１〜１２のアルキル基またはフェニル基を表し、ｎは０または１の整数を表す）
で表される環状酸無水物単量体単位が挙げられる。 In the present invention, the cyclic acid anhydride monomer unit that can constitute the copolymer (A) is derived from the cyclic acid anhydride monomer. Specific examples of the cyclic acid anhydride monomer unit include the following formula (2):

(Wherein R ¹ and R ² each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms or a phenyl group, and n represents an integer of 0 or 1)
The cyclic acid anhydride monomer unit represented by these is mentioned.

  As a halogen atom and a C1-C12 alkyl group, the thing similar to what was illustrated in the aromatic vinyl monomer unit represented by the said Formula (2) is mentioned.

R ¹ and R ² are preferably a hydrogen atom. R ¹ and R ² may be the same as or different from each other.

  Examples of cyclic acid anhydride monomers include maleic anhydride, glutaric anhydride, citraconic anhydride, dimethyl maleic anhydride, dichloromaleic anhydride, bromomaleic anhydride, dibromomaleic anhydride, phenylmaleic anhydride and diphenylanhydride. Maleic acid is mentioned, and maleic anhydride is preferred. Two or more cyclic acid anhydride monomers may be used in combination.

  The content of the cyclic acid anhydride monomer unit in the copolymer (A) is 100% of all monomer units constituting the copolymer (A) in terms of transparency and heat resistance of the acrylic resin composition. Preferably it is 5-35 mass% with respect to mass%, More preferably, it is 10-30 mass%, More preferably, it is 15-25 mass%.

  In the present invention, the copolymer (A) is a monomer unit, that is, an acrylic monomer unit, an aromatic vinyl monomer unit, and a cyclic acid anhydride unit as long as the effects of the present invention are not impaired. A monomer unit other than the monomer unit may be contained. Monomer units other than the monomer units described above are monomers that can be copolymerized with at least one monomer constituting the copolymer (A) among the monomers that lead to the monomer units described above. The monomer unit derived from the monomer may be used, and preferably, the acrylic monomer unit and the aromatic vinyl monomer unit constituting the copolymer (A), and the cyclic acid anhydride if included. It is a monomer unit derived from a monomer that can be copolymerized with all of the monomers that lead to the monomer unit. When the monomer unit other than the above-described monomer units is included, the content thereof is preferably 50% by mass or less with respect to 100% by mass of all the monomer units constituting the copolymer (A). Yes, more preferably 30% by mass or less, still more preferably 10% by mass or less. The lower limit of the content of monomer units other than the monomer units described above is, for example, 0% by mass or more.

  The weight average molecular weight (Mw) of the copolymer (A) is from the viewpoint of handling properties when molding a resin film from an acrylic resin composition or film handling properties when the acrylic resin film of the present invention is stretched, Moreover, since it becomes easy to make the melt mass flow rate of an acrylic resin composition 4.0 g / 10min or less, Preferably it is 90000-300000, More preferably, it is 100,000-250,000, More preferably, it is 110000-200000.

  The number average molecular weight (Mn) of the copolymer (A) is from the viewpoint of handling properties when molding a resin film from an acrylic resin composition or film handling properties when the acrylic resin film of the present invention is stretched, Moreover, since it becomes easy to make the melt mass flow rate of an acrylic resin composition 4.0 g / 10min or less, Preferably it is 35000-80000, More preferably, it is 40000-70000, More preferably, it is 45000-60000. In the present invention, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the copolymer (A) can be measured in terms of polymethyl methacrylate by gel permeation chromatography (GPC) measurement, for example.

  The molecular weight distribution (Mw / Mn) of the copolymer (A) is preferably 1.3 to 4, more preferably 1.5 to 3.5 from the viewpoint of moldability from the acrylic resin composition to the resin film. More preferably, it is 1.7-3.

  The melt mass flow rate (MFR) of the copolymer (A) is usually 0.5 g / 10 min or more, preferably 1.0 g / 10 min or more, more preferably 1.5 g / 10 min or more, preferably 10 g. / 10 min or less, more preferably 8 g / 10 min or less, and even more preferably 7 g / 10 min or less. When the MFR of the copolymer (A) is within the above range, the MFR of the acrylic resin composition can be lowered, and a hard coat liquid was applied onto the acrylic resin film formed from the resin composition. In this case, dissolution of the resin film by the solvent contained in the heart cord solution can be suppressed, and high surface hardness can be imparted to the hard coat layer to be formed. In the present invention, the MFR of the polymer can be measured according to JIS K7210 under the conditions of a measurement temperature of 230 ° C. and a load of 37.3N.

  The copolymer (A) is obtained by polymerizing each monomer constituting the copolymer by a known method such as a bulk polymerization method, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, or a cast polymerization method. Can be manufactured. By changing the amount of each monomer used, the content of each monomer unit in the copolymer (A) can be controlled.

  In the present invention, the content of the copolymer (A) in the acrylic resin composition is preferably 10 to 80% by mass, more preferably 15 to 65%, based on the total mass of the acrylic resin composition. It is mass%, More preferably, it is 20-55 mass%. When the content of the copolymer (A) in the acrylic resin composition is within the above range, an acrylic resin film that is difficult to dissolve in a solvent and can form high surface hardness can be obtained. Moreover, heat resistance can be improved and a resin film with good appearance can be obtained.

  Moreover, it is preferable that content of the aromatic vinyl monomer unit in an acrylic resin composition is 10-50 mass% on the basis of the total mass of an acrylic resin composition, and it is 12-45 mass%. Is more preferable, and it is still more preferable that it is 15-40 mass%. When the content of the aromatic vinyl monomer unit in the acrylic resin composition is within the above range, a hard coat layer having a sufficiently high surface hardness is formed on the acrylic resin film obtained from the resin. Can do.

<Polymer (B)>
In the present invention, the acrylic resin composition comprises a polymer (B) containing an acrylic monomer unit and not containing an aromatic vinyl monomer unit. By adding the polymer (B) in addition to the copolymer (A), the melt mass flow rate of the acrylic resin composition can be easily adjusted. Moreover, moderate toughness can be imparted to the acrylic resin film.

  The acrylic monomer unit constituting the polymer (B) is a monomer unit derived from methacrylic acid, acrylic acid, a methacrylic acid ester monomer, or an acrylic acid ester monomer. Examples of the monomer or the acrylate monomer include those similar to those exemplified above for the copolymer (A). Of these, methyl methacrylate and methyl acrylate are preferred. Two or more methacrylic acid ester monomers and / or acrylic acid ester monomers may be used. In particular, when the polymer (B) contains monomer units derived from two or more kinds of acrylate monomers, high transparency and heat decomposability can be ensured, and at the same time, melt mass flow rate. The adjustment becomes easier.

  When the acrylic monomer unit in the copolymer (A) and the acrylic monomer unit in the polymer (B) are the same, the compatibility of the resin composition and the transparency of the resulting resin film It is preferable that it tends to be excellent.

  The content of the acrylic monomer unit in the polymer (B) is usually 50% by mass or more, preferably 70% by mass with respect to 100% by mass of all the monomer units constituting the polymer (B). % Or more, more preferably 90% by mass or more, and still more preferably 92% by mass or more.

  The polymer (B) may contain other monomer units that are not aromatic vinyl monomer units in addition to the acrylic monomer units described above, as long as the effects of the present invention are not impaired. Examples of such other monomers include unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile; cyclic acid anhydride monomers such as maleic anhydride; and cyclic imide monomers such as phenylmaleimide and cyclohexylmaleimide Examples include the body.

  The weight average molecular weight (Mw) of the polymer (B) is preferably 40,000 to 200,000, more preferably 60000 to 180000, and still more preferably 80000 to 150,000, from the viewpoint of lowering the MFR.

  The number average molecular weight (Mn) of the polymer (B) is preferably 20000 to 100000, more preferably 30000 to 70000, and still more preferably 40000 to 60000, from the viewpoint of lowering the MFR. In the present invention, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer (B) can be measured, for example, in terms of polymethyl methacrylate by gel permeation chromatography (GPC) measurement.

  The molecular weight distribution (Mw / Mn) of the polymer (B) is preferably small from the viewpoint of the surface hardness of the acrylic resin film, preferably 1.3 to 4.0, more preferably 1.4 to 3.5. More preferably, it is 1.5-3.0.

  The MFR of the polymer (B) is preferably 10 g / 10 min or less, more preferably 5 g / 10 min or less, and further preferably 3 g / 10 min or less. When the MFR of the polymer (B) is not less than the above lower limit, the MFR of the acrylic resin composition can be easily adjusted. In addition, the upper limit of MFR of a polymer (B) is 40 g / 10min or less normally from a viewpoint of moldability.

  The polymer (B) is composed of a methacrylic acid ester monomer and / or an acrylic acid ester monomer, and other monomers as necessary, a bulk polymerization method, a solution polymerization method, an emulsion polymerization method, a suspension weight, It can manufacture by making it superpose | polymerize by well-known methods, such as a combined method and a casting polymerization method.

  The content of the polymer (B) in the acrylic resin composition is preferably 20% by mass or more, more preferably 30% by mass or more, with respect to the total mass of the acrylic resin composition. Preferably it is 80 mass% or less, More preferably, it is 70 mass% or less. When the content of the polymer (B) is not less than the above lower limit, the MFR of the acrylic resin composition can be easily controlled. The heat resistance of an acrylic resin composition can be improved as content of a polymer (B) is below the said upper limit, and a resin film with a favorable external appearance can be obtained.

  In one embodiment of the present invention, the acrylic resin composition may further contain rubber elastic particles from the viewpoint of improving the toughness, impact resistance and film forming property of the obtained resin film. The rubber elastic body particles are particles including a rubber elastic body layer exhibiting rubber elasticity. For example, the rubber elastic body particles may be a single-layered particle including only a rubber elastic body layer exhibiting rubber elasticity, or rubber exhibiting rubber elasticity. It may be a multi-layered particle (core-shell type particle) having another layer together with the elastic layer.

  Examples of the rubber elastic body constituting the rubber elastic body layer include an olefin elastic polymer, a diene elastic polymer, a styrene-diene elastic copolymer, an acrylic elastic polymer, and the like. Examples of the olefin-based elastic polymer include a polypropylene-based polymer and a polyethylene-based polymer. Examples of the diene elastic polymer include butadiene rubber and isoprene rubber. Examples of the styrene-diene-based elastic copolymer include a styrene-butadiene copolymer. Examples of the acrylic elastic polymer include a polymer or copolymer mainly composed of an acrylate ester.

  The particle diameter of the rubber elastic particles is, for example, 10 nm or more, preferably 50 nm or more, more preferably 100 nm or more, and for example, 350 nm or less, preferably 320 nm or less. When the particle diameter of the rubber elastic body particles is equal to or larger than the lower limit, the fluidity is hardly lowered when the acrylic resin composition is processed into a film. Moreover, the internal haze of an acrylic resin composition does not become high easily that the particle diameter of a rubber elastic body particle is below the said upper limit. The particle diameter of the rubber elastic particles can be measured as a number average particle diameter by observation with an electron microscope, and can be calculated as an average value of 100 rubber elastic particles, for example.

  The content of the elastic rubber particles in the acrylic resin composition may be 0 (zero)% by mass with respect to the total mass of the acrylic resin composition, but is preferably 5 to 30% by mass, preferably 7 to 28%. It is 10 mass%, More preferably, it is 10-25 mass%. The brittleness of the resin film obtained can be improved as content of the rubber elastic body particle in an acrylic resin composition is more than the said lower limit. When the content of the elastic rubber particles in the acrylic resin composition is not more than the above upper limit value, the heat resistance of the acrylic resin composition is improved, so that a resin film having a good appearance can be obtained.

  The 1% weight loss temperature of the rubber elastic particles is preferably 305 ° C. or higher, more preferably 310 ° C. or higher, and further preferably 315 ° C. or higher. When the 1% weight loss temperature of the rubber elastic particles is equal to or higher than the lower limit, the rubber elastic particles have good heat resistance, and the rubber elastic particles are hardly decomposed during melt-kneading and suppress foaming in the resin film. be able to. The upper limit of the 1% weight reduction temperature of the rubber elastic particles is, for example, 500 ° C. or less.

  In the present invention, the 1% weight loss temperature refers to a rubber elastic body when the rubber elastic body particles are previously dried at 80 ° C. for 12 hours or more and then heated at a rate of 10 ° C./min in a nitrogen atmosphere. It means the temperature when the weight loss of the particles becomes 1% of the total weight. The 1% weight loss temperature can be measured by differential thermal and thermogravimetric analysis (TG-DTA).

  In the present invention, the melt mass flow rate (MFR) of the acrylic resin composition is 4.0 g / 10 min or less. When the MFR of the acrylic resin composition exceeds 4.0 g / 10 minutes, when the hard coat liquid containing a solvent is applied onto the acrylic resin film composed of the resin composition, the acrylic resin is a solvent. Since it becomes easy to elute in and swells easily with a solvent, it is difficult to form a hard coat layer having a sufficiently high surface hardness even if the hard coat liquid is subsequently cured. In the present invention, the MFR of the acrylic resin composition is preferably 3.8 g / 10 min or less, more preferably 3.5 g / 10 min or less, and even more preferably 3.3 g / 10 min or less. Particularly preferably, it is 3.0 g / 10 min or less. In the present invention, the lower the MFR of the acrylic resin composition, the higher the surface hardness of the hard coat layer formed on the resulting acrylic resin film. The lower limit value of the MFR of the acrylic resin composition is not particularly limited, but is usually 0.5 g / 10 min or more from the viewpoint of moldability by melting. MFR can be measured in accordance with JIS K7210 under the conditions of a measurement temperature of 230 ° C. and a load of 37.3 N.

  The MFR of the acrylic resin composition can be adjusted, for example, by controlling the number average molecular weight, weight average molecular weight, molecular weight distribution, and the like of the copolymer (A) constituting the acrylic resin composition. The number average molecular weight, weight average molecular weight and molecular weight distribution of the copolymer (A) can be controlled, for example, by selecting a polymerization condition (a polymerization catalyst such as a living polymerization catalyst, a polymerization temperature, a polymerization time, and an additive). . In the present invention, the acrylic resin composition is composed of at least two types of polymers [that is, the copolymer (A) and the polymer (B)]. The MFR of the acrylic resin composition can be more easily controlled by adjusting the blending amount of the polymer (B) with respect to the polymer (A). By using the polymer (B) as a diluent, various acrylic resin compositions can be easily obtained using the same copolymer (A), which is advantageous from the productivity and industrial viewpoints. It is.

[Resin film]
As described above, the acrylic resin film of the present invention includes a copolymer (A) and a polymer (B), and is composed of an acrylic resin composition having an MFR of 4.0 g / 10 min or more. The hard coat layer is laminated on one side. The resin film of the present invention is obtained by mixing the copolymer (A) and the polymer (B), rubber elastic particles and other components as necessary to obtain an acrylic resin composition. As shown, it can be manufactured by forming into a film by melt extrusion molding and forming a hard coat layer on one side of the film. As a method for obtaining a film-like molded product from the acrylic resin composition, specifically, for example, the acrylic resin composition is melt-kneaded at the following melting temperature and / or residence time and molded into a film shape. Can be manufactured. Moreover, a resin film can also be produced by a method of forming an acrylic resin composition into a film by a solution casting film formation method, a hot press method, or the like. In particular, from the viewpoint of film thickness uniformity of resin film, manufacturing cost and environmental consideration, melt-kneading the acrylic resin composition at the following melting temperature by the melt extrusion molding method, and forming into a film shape It is preferable to produce a resin film.

Hereinafter, the method for producing the resin film of the present invention by the melt extrusion method will be further described with reference to FIG.
First, the copolymer (A) and the polymer (B) and, if necessary, rubber elastic particles and other components are added to obtain an acrylic resin composition. Next, the obtained acrylic resin composition was melt-kneaded by an extruder (1) such as a uniaxial or biaxial extruder at the following melting temperature, and continuously melted from a die (2) such as a T-die. Is extruded into a film. Further, the extruded film-like molten resin (3) is sandwiched between a pair of cooling rolls (first cooling roll (5) and second cooling roll (6)) having a smooth surface in the cooling unit (4). Then, if necessary, the resin film A can be produced in a non-stretched state by winding it around the third cooling roll (7), forming and cooling it. The method of mixing the copolymer (A), the polymer (B), the rubber elastic particles and other components is not particularly limited, and may be mixed by a known method, and a super mixer or a Banbury mixer may be used. Then, it may be melt kneaded with a single screw or twin screw extruder, or a combination thereof. Moreover, a 1st cooling roll, a 2nd cooling roll, and a 3rd cooling roll may be comprised with a metal roll or a metal elastic roll, and may be comprised combining a metal roll and a metal elastic roll.

  The melting temperature of each component in the acrylic resin composition is preferably 230 ° C. or higher and 280 ° C. or lower, more preferably 235 ° C. or higher and 270 ° C. or lower, and further preferably 240 ° C. or higher and 260 ° C. or lower. In the present invention, even when the melting temperature is within the above range, the acrylic resin composition is sufficiently melted, and a resin film having a good appearance without coloring can be obtained while ensuring good processability.

  The residence time when melt-kneading the acrylic resin composition, that is, the residence time until the acrylic resin composition passes through the extruder and exits the T die is preferably 20 minutes or more, more preferably 25 minutes or more. More preferably, it is 30 minutes or more, preferably 60 minutes or less, more preferably 45 minutes or less. In the present invention, even when the residence time of the acrylic resin composition is within the above range, the acrylic resin composition is sufficiently melted and the resin film has a good appearance without coloring while ensuring good processability. Can be obtained. In addition, a polymer filter may be disposed between the extruder and the T die, and in such a case, it is preferable to set the same residence time.

  The thickness of the resin film of the present invention (thickness not including the hard coat layer) is preferably 10 μm to 1000 μm, more preferably 20 μm to 500 μm, and still more preferably 20 μm to 300 μm.

  In the present invention, the acrylic resin film not containing a hard coat layer preferably has a light transmittance of 2% or less at a wavelength of 260 nm converted to a film thickness of 40 μm, and converted to a film thickness of 40 μm. The light transmittance at a wavelength of 380 nm is preferably 5% or less. When the light transmittance at wavelengths of 260 nm and 380 nm is less than or equal to the above upper limit, when the resin film of the present invention is used as a polarizer protective film, it is possible to prevent performance degradation of the liquid crystal cell.

  The acrylic resin film of the present invention is preferably a single-layer film, but may be a multilayer film having two or more layers as long as the effects of the present invention are not impaired. When the resin film is a multilayer film, each layer may be formed from an acrylic resin composition having the same composition, or may be formed from an acrylic resin composition having a different composition. Acrylic resin composition with different composition is different in the type of resin contained, the type of resin is the same but the content of each resin is different, the type and content of the resin are the same, other In any case, including those having different components. The term “single layer configuration” as used herein means that the configuration of the resin film portion serving as the substrate in the acrylic resin film of the present invention is a single layer, and a hard coat layer formed on the resin film. Is not included.

  The acrylic resin film of the present invention may be subjected to an antiglare treatment or an antifouling treatment as a surface treatment other than a hard coat treatment for providing a hard coat layer.

<Hard coat layer>
The acrylic resin film of the present invention has a hard coat layer on one surface thereof. By having the hard coat layer, the surface hardness of the acrylic resin film is increased, and for example, the effect of preventing scratches on the surface in an assembly operation of an image display device or the like is enhanced.

  In the acrylic resin film of the present invention, examples of the material for forming the hard coat layer include photocurable resins, thermosetting resins, electron beam curable resins, and inorganic materials such as silicon dioxide. From the viewpoints of productivity and hardness of the resulting film, a photocurable resin is preferred.

  Photocurable resins include, for example, polyfunctional acrylates; polyfunctional urethanized acrylates, polyol (meth) acrylates, and, if necessary, photocurability including (meth) acrylic polymers having an alkyl group containing two or more hydroxyl groups. Examples thereof include a resin mixture. Especially, since the adhesive force with respect to the acrylic resin film used as a base material is favorable and it is excellent in productivity, a photocurable resin mixture is preferable.

  Examples of the polyfunctional acrylate include dimethyl or tri-acrylate of trimethylolpropane, tri- or tetra-acrylate of pentaerythritol, polyfunctional which is a reaction product of acrylate having at least one hydroxyl group in the molecule and diisocyanate. Examples thereof include urethanized acrylate. These polyfunctional acrylates may be used alone or in combination of two or more.

  As a polyfunctional urethanized acrylate used when forming the said photocurable resin mixture, it manufactures using (meth) acrylic acid and / or (meth) acrylic acid ester, a polyol, and diisocyanate, for example. Specifically, by preparing hydroxy (meth) acrylate having at least one hydroxyl group in the molecule from (meth) acrylic acid and / or (meth) acrylic acid ester and polyol, and reacting it with diisocyanate, Multifunctional urethanized acrylates can be produced. The polyfunctional urethanized acrylate thus produced has a function as the above-described photocurable resin. In the production thereof, (meth) acrylic acid and / or (meth) acrylic acid ester may be used singly or in combination of two or more, respectively, and polyol and diisocyanate are similarly used. One type may be used, or two or more types may be used in combination.

  As the (meth) acrylic acid ester used for forming the polyfunctional urethanized acrylate, a linear or cyclic alkyl ester of (meth) acrylic acid can be used, and specific examples thereof include methyl (meth) acrylate. And alkyl (meth) acrylates such as ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and butyl (meth) acrylate; cycloalkyl (meth) acrylates such as cyclohexyl (meth) acrylate, and the like.

  The polyol used for forming the polyfunctional urethanized acrylate is a compound having at least two hydroxyl groups in the molecule, and specific examples thereof include ethylene glycol, propylene glycol, 1,3-propanediol, diethylene glycol, diethylene glycol, and diethylene glycol. Propylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 2,2,4-trimethyl- 1,3-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol ester of hydroxypivalic acid, cyclohexane dimethylol, 1,4-cyclohexane diol, spiro glycol, tricyclodecane dimethylol, hydrogenated bisphenol , Ethylene oxide-added bisphenol A, propylene oxide-added bisphenol A, trimethylolethane, trimethylolpropane, glycerin, 3-methylpentane-1,3,5-triol, pentaerythritol, dipentaerythritol, tripentaerythritol, glucose, etc. Is mentioned.

  The diisocyanate used in forming the polyfunctional urethanized acrylate is a compound having two isocyanato groups (—NCO) in the molecule, and various aromatic, aliphatic or alicyclic diisocyanates can be used. Specific examples thereof include tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 2,4-tolylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 3,3′-dimethyl-4, Examples thereof include 4′-diphenyl diisocyanate, xylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4′-diphenylmethane diisocyanate, and a nuclear hydrogenated diisocyanate having an aromatic ring among these.

  The polyol (meth) acrylate used when forming the photocurable resin mixture is a (meth) acrylate of a compound having at least two hydroxyl groups in the molecule (that is, a polyol). Examples include pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and the like. These polyol (meth) acrylates may be used alone or in combination, and preferably contain pentaerythritol triacrylate and / or pentaerythritol tetraacrylate.

  The (meth) acrylic polymer having an alkyl group containing two or more hydroxyl groups used in forming the photocurable resin mixture has an alkyl group containing two or more hydroxyl groups in one structural unit, Specific examples thereof include a polymer containing 2,3-dihydroxypropyl (meth) acrylate as a constituent unit, and a polymer containing 2-hydroxyethyl (meth) acrylate as a constituent unit together with 2,3-dihydroxypropyl (meth) acrylate. Etc.

  As described above, by using the acrylic photo-curing resin as exemplified, the hard coat can improve the adhesion with the acrylic resin film, improve the mechanical strength, and effectively prevent the surface from being scratched. A layer can be obtained.

Such a photocurable resin is preferably used as a photocurable resin composition in combination with a photopolymerization initiator.
Examples of the photopolymerization initiator include acetophenone series, benzophenone series, benzoin ether series, amine series, and phosphine oxide series.

Examples of the acetophenone photopolymerization initiator include 2,2-dimethoxy-2-phenylacetophenone (also known as benzyldimethyl ketal), 2,2-diethoxyacetophenone, and 1- (4-isopropylphenyl) -2-hydroxy-2. -Methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2-morpholino-1- (4-methylthiophenyl) propan-1-one and the like.
Examples of the benzophenone photopolymerization initiator include benzophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, and the like.
Examples of the benzoin ether photopolymerization initiator include benzoin methyl ether and benzoin propyl ether.
Examples of the amine photopolymerization initiator include N, N, N ′, N′-tetramethyl-4,4′-diaminobenzophenone (also known as Michler's ketone).
Examples of the phosphine oxide photopolymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide.
In addition, xanthone compounds and thioxant compounds can also be used as photopolymerization initiators.

  As a commercial product of the photopolymerization initiator, a commercial product may be used. For example, “Irgacure 907” and “Irgacure 184” sold by Ciba, Switzerland, and BASF, Germany. “Lucirin TP0” and the like.

You may make a photocurable resin composition contain a leveling agent etc. as needed.
Examples of the leveling agent include a fluorine-based or silicone-based leveling agent.
Examples of the silicone-based leveling agent include reactive silicone; polydimethylsiloxane, polyether-modified polydimethylsiloxane, polymethylalkylsiloxane, and the like, among which reactive silicone and siloxane-based leveling agent are preferable.
When a leveling agent made of reactive silicone is used, the surface of the hard coat layer is provided with slipperiness, and excellent scratch resistance can be maintained for a long period of time. Further, if a siloxane leveling agent is used, film formability can be improved.

  In the present invention, the hard coat layer is obtained by applying a hard coat solution containing a solvent to one side of an acrylic resin film serving as a base material, drying the hard coat solution, and further curing the dried hard coat solution. Can be formed. Therefore, the method for producing an acrylic resin film of the present invention includes a step of applying a hard coat solution containing a solvent to one side of the acrylic resin film, a step of drying the hard coat solution after coating, and a step after drying. A step of curing the hard coat solution.

In the present invention, the hard coat liquid can be prepared, for example, by adding and mixing a solvent to the photocurable resin composition.
As a solvent, it can select suitably from the organic solvent which can melt | dissolve each component which comprises a photocurable resin composition, for example, ester solvent, ketone solvent, aromatic solvent, alcohol solvent, amide system A solvent etc. are mentioned. As the solvent, only one kind may be used alone, or two or more kinds may be used in combination.

Specific examples of the solvent include the following.
Ester solvent: For example, methyl acetate, ethyl acetate, isopropyl acetate, isobutyl acetate, butyl acetate and the like.
Ketone solvents: for example, acetone, methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone and the like.
Aromatic solvents: for example, benzene, toluene, xylene, mesitylene, cumene and the like.
Alcohol solvents: For example, methanol, ethanol, isopropyl alcohol, ethylene glycol, propylene glycol, glycerin and the like.
Amide solvent: For example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone and the like.
The solvent is preferably an ester solvent, a ketone solvent, an alcohol solvent and an aromatic solvent, more preferably an ester solvent and an alcohol solvent, and even more preferably an ester solvent from the viewpoint of solubility in a resin film.

  The content of the solvent in the hard coat liquid may be appropriately determined according to the type of the photocurable resin and the solvent to be used, the desired viscosity of the hard coat liquid, applicability, film thickness, etc., but the solid content concentration is usually It is used so that it may become 20-80 mass%, Preferably it is 30-70 mass%.

  The method for applying the hard coat liquid to one side of the acrylic resin film to be the base material is not particularly limited, and methods known in the art can be used. For example, a method of applying a hard coat solution onto the surface of an acrylic resin film using a bar coater or the like, a method of spraying a hard coat solution onto the surface of a resin film, and the like can be mentioned.

  The hard coat liquid after coating can be dried by, for example, heat drying, vacuum drying, air drying or the like. The drying temperature may be appropriately determined depending on the components of the hard coat solution, but is preferably 60 ° C. or higher and 70 ° C. or higher from the viewpoint of efficiently removing (drying) the solvent contained in the hard coat solution. More preferably. Further, if the drying temperature is too high, the acrylic resin film serving as the base material is easily dissolved in the hard coat liquid, or the acrylic resin film is likely to swell, and is preferably 100 ° C. or lower. More preferably, it is 95 ° C. or lower. The drying time is usually 0.5 to 30 minutes.

The method for curing the hard coat liquid after drying may be appropriately selected depending on the material for forming the hard coat layer. For example, when a material that is cured by light is included, irradiation with active energy rays such as ultraviolet rays and electron beams is performed. The hard coat solution can be cured to obtain a hard coat layer. As the active energy ray, ultraviolet rays are preferable from the viewpoints of ease of use, ease of preparation of the active energy ray-curable adhesive, stability, and curing performance. Examples of the ultraviolet light source include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, and a metal halide lamp. Irradiation conditions may be suitably determined in accordance with the light source used, typically, accumulated light amount is 400~1500mJ / cm ^2, preferably 600~1200mJ / cm ^2. Moreover, when the hard coat liquid contains a material that is cured by heat, the hard coat liquid can be cured by heating to obtain a hard coat layer.

  The thickness of the hard coat layer is usually about 0.1 to 30 μm, preferably 1 to 10 μm.

[Polarizer protective film]
The acrylic resin film of the present invention is suitable as a polarizer protective film. That is, in another embodiment of the present invention, there is provided a polarizer protective film comprising the resin film of the present invention (hereinafter also referred to as “polarizer protective film of the present invention”). In addition, a polarizer protective film is a film used in order to laminate | stack on one or both surfaces of a polarizer, and to protect a polarizer.

〔Polarizer〕
In another embodiment of the present invention, there is provided a polarizing plate (hereinafter also referred to as “polarizing plate of the present invention”) in which a polarizer is laminated on the surface opposite to the hard coat layer of the acrylic resin film of the present invention. Is done. It is preferable that the polarizer protective film and the polarizer are bonded via an adhesive layer or an adhesive layer.

  A polarizer is an optical film having a function of emitting polarized light with respect to incident light such as natural light. The polarizer has a property of absorbing linearly polarized light having a vibration surface in a certain direction incident on the film surface and transmitting linearly polarized light having a vibration surface perpendicular to the polarizing surface, and in a certain direction incident on the film surface. There are a polarization separator having a property of reflecting linearly polarized light having a vibration surface and transmitting linearly polarized light having a vibration surface orthogonal thereto, and an elliptical polarizer in which a polarizing film and a retardation film are laminated. As a suitable specific example of a polarizer, particularly a linear polarizer (also referred to as a polarizing film), a uniaxially stretched polyvinyl alcohol resin film is adsorbed and oriented with a dichroic dye such as iodine or a dichroic dye. Can be mentioned. The thickness of the polarizer is usually 5 μm to 40 μm.

  A transparent resin film may be disposed on the surface of the polarizer opposite to the surface on which the acrylic resin film of the present invention is disposed. Examples of the transparent resin film include a triacetyl cellulose film, a polycarbonate film, a polyethylene terephthalate film, an acrylic resin film, a laminated film of an acrylic resin and a polycarbonate resin, and an olefin resin film.

  The polarizer protective film of the present invention and the polarizer are preferably bonded via an adhesive layer or an adhesive layer. Prior to bonding, at least one of the bonding surfaces is preferably subjected to corona discharge treatment, plasma irradiation treatment, electron beam irradiation treatment, or other surface activation treatment. By surface activation treatment, it is excellent in adhesive strength when bonded to a polarizer with an adhesive or a pressure-sensitive adhesive.

  As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, a conventionally known pressure-sensitive adhesive can be used without particular limitation, and for example, a pressure-sensitive adhesive having a base polymer such as acrylic, rubber-based, urethane-based, silicone-based, or polyvinyl ether-based. Can be used. Moreover, an active energy ray hardening-type adhesive, a thermosetting type adhesive, etc. may be sufficient. Among these, an adhesive having an acrylic resin having excellent transparency, adhesive strength, reworkability, weather resistance, heat resistance and the like as a base polymer is preferable.

  The acrylic pressure-sensitive adhesive is not particularly limited, but (meth) such as butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, etc. Acrylic acid ester base polymers and copolymer base polymers containing two or more of these (meth) acrylic acid esters are preferably used. Furthermore, polar monomers are copolymerized in these base polymers. Examples of polar monomers include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) acrylamide, and 2-N, N-dimethylaminoethyl (meth). Mention may be made of monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, etc., such as acrylate and glycidyl (meth) acrylate.

  These acrylic pressure-sensitive adhesives can be used alone, but are usually used in combination with a crosslinking agent. As the crosslinking agent, a divalent or polyvalent metal ion that forms a carboxylic acid metal salt with a carboxyl group, a polyamine compound that forms an amide bond with a carboxyl group, Examples thereof include polyepoxy compounds and polyol compounds that form an ester bond with a carboxyl group, and polyisocyanate compounds that form an amide bond with a carboxyl group. Among these, polyisocyanate compounds are widely used.

  The active energy ray-curable pressure-sensitive adhesive has the property of being cured by irradiation with active energy rays such as ultraviolet rays and electron beams. It is a pressure-sensitive adhesive that has the property of adhering to an adherend and curing by irradiation with active energy rays to adjust the adhesion. As the active energy ray-curable adhesive, it is particularly preferable to use an ultraviolet curable adhesive. The active energy ray-curable pressure-sensitive adhesive generally comprises an acrylic pressure-sensitive adhesive and an active energy ray-polymerizable compound as main components. Usually, a crosslinking agent is further blended, and a photopolymerization initiator and a photosensitizer can be blended as necessary.

  In addition to the above base polymer and cross-linking agent, the pressure-sensitive adhesive layer can be used, for example, to adjust the pressure-sensitive adhesive force, cohesive force, viscosity, elastic modulus, glass transition temperature, etc. Additives such as resins, tackifier resins, silane compounds, antioxidants, antistatic agents, ultraviolet absorbers, dyes, pigments, antifoaming agents, corrosive agents, photopolymerization initiators, thermal polymerization initiators May be included. Furthermore, it can also be set as the adhesive layer which contains microparticles | fine-particles and shows light-scattering property. Examples of ultraviolet absorbers include salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, and nickel complex compounds.

  In a preferred embodiment, the polarizing plate of the present invention may have a polarizer and an acrylic resin film bonded via an adhesive layer.

  The adhesive which comprises an adhesive bond layer can be arbitrarily selected and used from the thing which expresses the adhesive force with respect to each member. Typically, a water-based adhesive, that is, an active energy ray-curable adhesive containing an adhesive component dissolved in water or an adhesive component dispersed in water, or a component that cures upon irradiation with active energy rays is used. Can be mentioned. Among these, an active energy ray-curable adhesive is preferable from the viewpoint of productivity.

  As the water-based adhesive, a composition using a polyvinyl alcohol resin or a urethane resin as a main component is preferable. When a polyvinyl alcohol-based resin is used as the main component of the aqueous adhesive, the polyvinyl alcohol-based resin includes partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, as well as carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, and methylol. Examples thereof include modified polyvinyl alcohol resins such as group-modified polyvinyl alcohol and amino group-modified polyvinyl alcohol. When using a polyvinyl alcohol-based resin as the adhesive component, the adhesive is often prepared as an aqueous solution of a polyvinyl alcohol-based resin. The concentration of the polyvinyl alcohol resin in the adhesive aqueous solution is preferably 1 to 10 parts by mass and more preferably 1 to 5 parts by mass with respect to 100 parts by mass of water.

  In order to improve the adhesiveness, it is preferable to add a curable component such as glyoxal or a water-soluble epoxy resin or a crosslinking agent to the water-based adhesive having a polyvinyl alcohol resin as a main component. Examples of water-soluble epoxy resins include polyamide polyamines obtained by reacting a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with a polycarboxylic acid such as adipic acid and epichlorohydrin. An epoxy resin etc. are mentioned. Commercially available products may be used as the polyamide polyamine epoxy resin, such as “Smiles Resin 650” and “Smiles Resin 675” manufactured by Taoka Chemical Co., Ltd., “WS-525” manufactured by Seiko PMC Co., Ltd. Is mentioned. The addition amount of the curable component or the crosslinking agent is preferably 1 to 100 parts by mass, more preferably 1 to 50 parts by mass with respect to 100 parts by mass of the polyvinyl alcohol resin. When the addition amount is small, the effect of improving the adhesiveness is reduced, while when the addition amount is large, the adhesive layer may become brittle.

  When a urethane resin is used as the main component of the aqueous adhesive, a mixture of a polyester ionomer type urethane resin and a compound having a glycidyloxy group can be given as an example of a suitable adhesive composition. The polyester ionomer type urethane resin here is a urethane resin having a polyester skeleton, into which a small amount of ionic component (hydrophilic component) is introduced. An ionomer type urethane resin is directly emulsified in water without using an emulsifier and becomes an emulsion, so that it is preferable as an aqueous adhesive.

  When an active energy ray-curable adhesive is used, components that cure by irradiation of active energy rays that constitute the active energy ray (hereinafter sometimes simply referred to as “curable components”) include epoxy compounds, oxetane compounds, and acrylic compounds. Etc. When a cationically polymerizable compound such as an epoxy compound or an oxetane compound is used, a cationic polymerization initiator is blended. Further, when a radical polymerizable compound such as an acrylic compound is used, a radical polymerization initiator is blended. Among these, an adhesive having an epoxy compound as one of the curable components is preferable, and an adhesive having an alicyclic epoxy compound in which an epoxy group is directly bonded to a saturated carbocycle as one of the curable components is more preferable. Moreover, you may use an oxetane compound together.

As the epoxy compound, commercially available products may be used. For example, “Epicoat” series manufactured by Mitsubishi Chemical Corporation, “Epicron” series manufactured by DIC Corporation, “Epototo” series manufactured by Nippon Steel & Sumitomo Metal Corporation, ADEKA Corporation “Adeka Resin” series manufactured by Nagase ChemteX Corporation, “Denacol” series manufactured by Nagase ChemteX Corporation, “Dow Epoxy” series manufactured by Dow Chemical Co., “Tepic” manufactured by Nissan Chemical Industries, Ltd., and the like.
As the alicyclic epoxy compound in which the epoxy group is directly bonded to the saturated carbocyclic ring, a commercially available product may be used. For example, “Celoxide” series and “Cyclomer” series manufactured by Daicel Chemical Industries, Ltd., Dow -The “Syracure” series manufactured by Chemical Company, etc.
As the oxetane compound, commercially available products may be used, and examples thereof include “Aron Oxetane” series manufactured by Toagosei Co., Ltd., “ETERRNACOLL” series manufactured by Ube Industries, Ltd., and the like.

  As the cationic polymerization initiator, commercially available products may be used. For example, “Kayacure” series manufactured by Nippon Kayaku Co., Ltd., “Syracure” series manufactured by Dow Chemical Co., Ltd., photoacid generator manufactured by San Apro Co., Ltd. “CPI” series, photo acid generators “TAZ”, “BBI” and “DTS” manufactured by Midori Chemical Co., Ltd., “Adekaoptomer” series manufactured by ADEKA Co., Ltd., “RHODORSIL” manufactured by Rhodia Series.

  The active energy ray-curable adhesive can contain a photosensitizer as necessary. By using a photosensitizer, the reactivity is improved, and the mechanical strength and adhesive strength of the cured product layer can be further improved. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, anthracene compounds, halogen compounds, and photoreducible dyes.

  Various additives can be blended with the active energy ray-curable adhesive within a range that does not impair the adhesiveness. Examples of the additive include an ion trap agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow regulator, a plasticizer, and an antifoaming agent. Furthermore, a curable component that cures by a reaction mechanism different from cationic polymerization can be blended within a range that does not impair the adhesion.

  In a preferred embodiment, the polarizer and the acrylic resin film of the polarizing plate of the present invention may be bonded via an adhesive layer.

  In the present invention, a pressure-sensitive adhesive or an adhesive is applied to the polarizer and / or the polarizer protective film of the present invention to form a coating film, and the polarizer and the polarizer protection of the present invention are protected via the formed coating film. The polarizer and the polarizer protective film of the present invention are bonded by overlapping the film and curing the pressure-sensitive adhesive or adhesive by irradiating active energy rays or by drying, and polarizing plate of the present invention Can be obtained.

  Application of the pressure-sensitive adhesive or adhesive to the polarizer and / or the polarizer protective film of the present invention can be carried out by a known method, for example, casting method, Mayer bar coating method, gravure coating method, comma coater method. A doctor blade method, a die coating method, a dip coating method, a spraying method, or the like can be used.

  Examples of the active energy rays include X-rays, ultraviolet rays, and visible rays. Among these, ultraviolet rays are preferable from the viewpoints of ease of use, ease of preparation of the active energy ray-curable adhesive, stability, and curing performance. Examples of the ultraviolet light source include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, and a metal halide lamp. Moreover, what is necessary is just to determine suitably the light irradiation intensity | strength and irradiation amount of an active energy ray by the composition of the active energy ray hardening-type adhesive and adhesive agent to be used.

  The drying treatment is performed, for example, by blowing hot air, and the temperature is usually in the range of 40 to 100 ° C, preferably in the range of 60 to 100 ° C. The drying time is usually about 20 to 1200 seconds.

  The thickness of an adhesive layer is 1-50 micrometers normally, Preferably it is 5-30 micrometers. Moreover, the thickness of an adhesive bond layer is 0.01-10 micrometers normally, Preferably it is 0.01-5 micrometers. The thickness of an adhesive layer and an adhesive bond layer can be adjusted with the thickness of the coating film formed in a polarizer or the polarizer protective film of this invention.

  The polarizing plate of the present invention can be used in an image display device in combination with a display element such as a liquid crystal cell or an organic EL element. For example, it can be attached to a liquid crystal cell to form a liquid crystal panel used in a liquid crystal display device. It is preferable that the polarizing plate and the liquid crystal cell are bonded via an adhesive layer using an adhesive. As an adhesive which comprises this adhesive layer, the thing similar to what was illustrated previously as an adhesive which can be used in order to adhere | attach a polarizer and the polarizer protective film of this invention is mentioned. Since the polarizing plate of the present invention includes a hard coat layer having a high surface hardness, for example, the polarizing plate surface is unlikely to be scratched during assembly operations of an image display device, and includes such a polarizer protective film. The image display device can exhibit high visibility due to the good appearance of the resin film.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all by these Examples.

The extrusion apparatus used in Examples and Comparative Examples is the apparatus shown in FIG. 1, and the configuration thereof is as follows.
Extruder: Screw diameter 65mm, single screw, vented extruder (manufactured by Toshiba Machine Co., Ltd.)
・ T-die: Multi-manifold die with a width of 800 mm and a lip interval of 1 mm (manufactured by Hitachi Zosen)
-1st cooling roll: Metal elastic roll-2nd cooling roll: Metal roll-3rd cooling roll: Metal roll

  The metal elastic roll has a 2 mm thick stainless steel thin film with one side mirrored so as to cover the outer periphery of the shaft roll made of stainless steel so that the mirror finished surface is the outer surface of the roll. It is a metal elastic roll having an outer diameter of 250 mm, in which a fluid made of heat transfer oil is sealed between the metal thin film. The metal roll is a spiral roll made of stainless steel having a mirror-finished surface and having an outer diameter of 250 mm.

[Acrylic resin composition]
Table 1 shows the monomer unit composition and general physical properties of the copolymers (A) (polymers A-1 and A-2) used in Examples 1 to 5 and Comparative Examples 1 and 2. Table 2 shows the monomer unit composition and general physical properties of the polymer (B) (polymers B-1 to B-4).
The weight average molecular weight (Mw) and number average molecular weight (Mn) of each polymer were determined by gel permeation chromatography (GPC) measurement (in terms of polymethyl methacrylate).
The MFR (measurement temperature 230 ° C., load 37.3 N) of each polymer was measured according to JIS K7210. The copolymer (A) and polymer (B) used were all colorless and transparent pellets.

The rubber elastic particles used in Examples 1 to 5 and Comparative Examples 1 and 2 were all core-shell type butadiene rubber. The rubber elastic particles used were all white (uncolored) powder. Table 3 shows the characteristics of the rubber elastic particles (rubbers 1 and 2).
The 1% weight loss temperature (° C.) was measured according to the following method.

[Measurement of 1% weight loss temperature]
About 5 mg of rubber 1 and rubber 2 are placed in an aluminum pan, respectively, and the weight of the sample is weighed, and weighed under the following conditions using a differential thermothermal gravimetric simultaneous measurement device SII TG / DTA6200 (Hitachi High-Tech Science). Went.
Pan: φ5 cylindrical sample cup made of aluminum (Seiko Instruments Inc. SSC00E030)
Sample amount: about 5mg
Measurement temperature: room temperature (23 ° C.) to 400 ° C.
Temperature increase rate: 10 ° C./min Atmosphere: N ² 200 mL / min

  According to the composition shown in Table 4 (each by mass), the copolymer (A), the polymer (B) and the rubber elastic particles were put into an extruder, and melt-kneaded at 230 ° C. and an average residence time of 10 minutes. Resin pellets of an acrylic resin composition were obtained. The MFR (measurement temperature 230 ° C., load 37.3 N) of the obtained acrylic resin composition was measured according to JIS K7210. The results are shown in Table 4.

[Production of resin film]
The extruder, the T die, and the first to third cooling rolls were arranged as shown in FIG. Next, the obtained resin pellets of the acrylic resin composition were melt kneaded at 245 ° C. with an extruder, and each was supplied to a T-die having a set temperature of 245 ° C. A film-like molten resin extruded from a T-die is sandwiched between a first cooling roll and a second cooling roll arranged opposite to each other, wound around a third cooling roll, molded and cooled, and an acrylic resin film having a thickness of 60 μm Got. The residence time from exiting the extruder to the T-die was 30 minutes. In addition, the surface temperature of the 1st cooling roll was 80 degreeC, the surface temperature of the 2nd cooling roll was 80 degreeC, and the surface temperature of the 3rd cooling roll was 100 degreeC. These temperatures are values obtained by actually measuring the surface temperature of each cooling roll.

[Hard coat layer]
The following components were mixed to prepare a hard coat solution.
Pentaerythritol triacrylate (Shin Nakamura Chemical Co., Ltd.) 20 parts by mass Pentaerythritol tetraacrylate (Shin Nakamura Chemical Co., Ltd.) 15 parts by mass Polyfunctional urethanized acrylate (reaction product of hexamethylene diisocyanate and pentaerythritol triacrylate) 5 parts by mass Parts Lucillin TPO (manufactured by BASF, chemical name: 2,4,6-trimethylbenzoyldiphenylphosphine oxide) 5 parts by mass Irgacure 184 (manufactured by BASF, chemical name: 1-hydroxy-cyclohexyl-phenyl-ketone) 0.5 Mass part Ethyl acetate 40 parts by mass Butyl acetate 20 parts by mass BYK3550 (BIC Chemie Japan Co., Ltd.) 0.5 parts by mass

The hard coat liquid was applied to the surface of the resin film having a thickness of 60 μm that was in contact with the second cooling roll using a bar coater so that the film thickness after curing was about 3 μm. Next, the coating layer is formed by heating and drying in a dryer at 80 ° C. for 1 minute, and integration is performed using an ultraviolet irradiation device with a belt conveyor (the lamp is an “H bulb” manufactured by Fusion UV Systems). Under the condition that the light quantity is 400 mJ / cm ² (UVA), ultraviolet rays are irradiated twice (the total accumulated light quantity is 800 mJ / cm ² (UVA)), and the coating layer made of the hard coat liquid is cured to hard coat. A layer was formed.

[Pencil hardness test]
According to JIS-K5600-5-4, the pencil hardness of the surface that was in contact with the second cooling roll before the hard coat and the hard coat surface were measured. For pencil hardness, set the acrylic resin film to be tested on soda glass, bring the pencil into contact with the test surface, and press the pencil at a test speed of 0.5 mm / sec to check for scratches on the surface of the resin film. The hardness of the hardest pencil was taken as the pencil hardness. The results are shown in Table 5.

  In the acrylic resin films of Examples 1 to 5 made of an acrylic resin composition having an MFR of 4.0 g / 10 min or less, the amount of change in surface hardness before and after the hard coat treatment is large, and the acrylic resin as a base material It was confirmed that the surface hardness can be effectively increased even when the surface hardness of the film is relatively soft.

DESCRIPTION OF SYMBOLS 1 Extruder 2 Die 3 Film-like molten resin 4 Cooling unit 5 1st cooling roll 6 2nd cooling roll 7 3rd cooling roll A Resin film

Claims (5)

An acrylic resin film having a hard coat layer laminated on one side, comprising the following copolymer (A) and polymer (B), and having a melt mass flow rate of 4.0 g / 10 min or less Acrylic resin film composed of materials.
Copolymer (A): Polymer containing acrylic monomer units and aromatic vinyl monomer units Polymer (B): Containing acrylic monomer units and no aromatic vinyl monomer units Polymer   2. The acrylic resin according to claim 1, wherein the acrylic resin composition comprises 0 to 30% by mass of rubber elastic body particles having an average particle diameter of 10 nm to 350 nm based on the total mass of the acrylic resin composition. the film.   A polarizer protective film comprising the acrylic resin film according to claim 1.   The polarizing plate by which the polarizer was laminated | stacked through the adhesive layer or the adhesive bond layer on the surface on the opposite side to the hard-coat layer of the acrylic resin film in any one of Claims 1-3. Applying a hard coat solution containing a solvent to one side of the acrylic resin film;
The manufacturing method of the acrylic resin film in any one of Claims 1-4 including the process of drying the hard-coat liquid after coating, and the process of hardening the hard-coat liquid after drying.

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