WO2019003980A1

WO2019003980A1 - Method for manufacturing optical film

Info

Publication number: WO2019003980A1
Application number: PCT/JP2018/023104
Authority: WO
Inventors: 壮悟幸本
Original assignee: 日本ゼオン株式会社
Priority date: 2017-06-29
Filing date: 2018-06-18
Publication date: 2019-01-03
Also published as: JP7088187B2; JPWO2019003980A1; TW201905051A

Abstract

This method for manufacturing an optical film includes: a step for forming a resin layer on a temporary support surface of a temporary support having the temporary support surface in which the surface free energy is equal to or less than 20 mJ/m2; a step for applying a hydrophilic treatment to the film surface of a base film formed by a resin which includes an alicyclic structure-containing polymer so that the surface free energy on the film surface becomes 40 mJ/m2 or greater; a step for sticking together the resin layer formed on the temporary support surface of the temporary support and the hydrophilically treated film surface of the base film; a step for removing the temporary support; and a step for applying a heat treatment to the resin layer and the base film at a temperature equal to or higher than the glass transition temperature of the alicyclic structure-containing polymer.

Description

Optical film manufacturing method

The present invention relates to a method of producing an optical film.

In a display device such as a liquid crystal display device or an organic electroluminescence display device, an optical film made of a resin may be provided. As such an optical film, a film formed of a resin containing an alicyclic structure-containing polymer is known (for example, Patent Documents 1 and 2).

JP, 2010-107958, A International Publication No. 2014/175312

When a film formed of a resin containing an alicyclic structure-containing polymer is used as an optical film, an appropriate resin layer may be provided on the surface. For example, an easily adhesive layer may be formed on the surface of a film formed of a resin containing an alicyclic structure-containing polymer by a resin suitable for enhancing adhesion. In general, a film formed of a resin containing an alicyclic structure-containing polymer has poor adhesion, and it has been difficult to bond other members with other members with high adhesive strength, as described above. By using the easy adhesion layer, it is possible to bond to the above-mentioned member with high adhesion strength.

It was normal for resin layers, such as an easily bonding layer, to be formed by the coating method with respect to the film formed with the resin containing an alicyclic structure containing polymer. Specifically, it is common to apply a coating liquid containing a material of a resin layer to a film formed of a resin containing an alicyclic structure-containing polymer, and then to dry it to form a resin layer. The However, in the field of industrial production, methods other than the coating method may be desired as a method of forming a resin layer on a film formed of a resin containing an alicyclic structure-containing polymer.

For example, in the case of forming a resin layer on both sides of a film formed of a resin containing an alicyclic structure-containing polymer by a coating method, it is required to form a resin layer on each side due to the nature of the coating method. The number of processes is increased, which tends to increase the manufacturing cost. Therefore, development of methods other than the coating method is desired from a viewpoint of controlling a manufacturing cost by forming a resin layer simultaneously on both surfaces. Also, as in the above example, as a method of forming a resin layer, the method other than the coating method is also used except for forming a resin layer on both sides of a film formed of a resin containing an alicyclic structure-containing polymer. May be desired.

Therefore, the inventor examined a transfer method as a method of forming a resin layer on the surface of a film formed of a resin containing an alicyclic structure-containing polymer. In the transfer method, a resin layer formed on a temporary support is bonded to a film formed of a resin containing an alicyclic structure-containing polymer, and then the temporary support is peeled off to obtain an alicyclic structure. A resin layer is formed on the surface of a film formed of a resin containing a containing polymer. However, since a film formed of a resin containing an alicyclic structure-containing polymer generally has poor adhesion to the resin layer, the resin layer formed by the transfer method tends to be easily peeled off from the film. . In particular, since a film formed of a resin containing an alicyclic structure-containing polymer tends to further decrease in adhesion after stretching, it is particularly difficult to form a resin layer on a stretched film by a transfer method.

Moreover, when the present inventor examined, when the polymer having an alicyclic structure containing crystallinity is used, a film formed of a resin containing the polymer having an alicyclic structure has adhesiveness to the resin layer. Was found to be particularly low. Furthermore, the adhesiveness to the resin layer of the film formed of a resin containing an alicyclic structure-containing polymer having crystallinity is further reduced as crystallization of the alicyclic structure-containing polymer proceeds, and the resin layer It has been found that the peeling of the

The present invention has been made in view of the above problems, and a film surface of a base film formed of a resin containing an alicyclic structure-containing polymer and a resin layer formed on a temporary support And an optical film including a base film and a resin layer which is difficult to peel from the base film can be manufactured.

As a result of intensive studies to solve the above problems, the inventor of the present invention forms a resin layer on the temporary support surface of a temporary support having a temporary support surface having a predetermined surface free energy, and a film surface of a base film A step of subjecting the film surface to a hydrophilic treatment so that the surface free energy of the film surface falls within a predetermined range, a resin layer formed on the temporary support surface of the temporary support, and the film surface subjected to the hydrophilic treatment The manufacturing method includes the steps of bonding, temporary support peeling, and heat treating the resin layer and the base film at a temperature higher than the glass transition temperature of the alicyclic structure-containing polymer. We have found that the problem is solved and completed the present invention.
That is, the present invention includes the following.

[1] A step of forming a resin layer on the temporary support surface of a temporary support having a temporary support surface having a surface free energy of 20 mJ / m ² or less,
A step of subjecting a film surface of a base film formed of a resin containing an alicyclic structure-containing polymer to a hydrophilic treatment such that the surface free energy of the film surface is 40 mJ / m ² or more,
Bonding the resin layer formed on the temporary support surface of the temporary support and the film surface subjected to the hydrophilic treatment of the base film,
Peeling the temporary support, and
A method of producing an optical film, comprising the step of heat treating the resin layer and the base film at a temperature equal to or higher than the glass transition temperature of the alicyclic structure-containing polymer.
[2] The method for producing an optical film according to [1], wherein the alicyclic structure-containing polymer has crystallinity.
[3] The method for producing an optical film according to [2], wherein the degree of crystallization of the alicyclic structure-containing polymer is less than 3% before the film surface is subjected to a hydrophilic treatment.
[4] The method for producing an optical film according to [2] or [3], wherein crystallization of the alicyclic structure-containing polymer proceeds in the step of subjecting the resin layer and the base film to the heat treatment.
[5] the step of applying the heat treatment to the resin layer and the base film,
Stretching the substrate film;
And 2. a step of promoting crystallization of the alicyclic structure-containing polymer contained in the base film after stretching, the method for producing an optical film according to any one of [2] to [4].
[6] The method for producing an optical film according to any one of [1] to [5], wherein the hydrophilic treatment is at least one selected from the group consisting of corona treatment, plasma treatment and excimer treatment.
[7] In any one of [1] to [6], the resin layer is formed of at least one selected from the group consisting of a urethane resin, an olefin resin, a polyester resin, an epoxy resin, and an acrylic resin. The manufacturing method of the optical film as described.

According to the present invention, the film surface of the base film formed of a resin containing an alicyclic structure-containing polymer and the resin layer formed on the temporary support are attached to each other to form a base film and the base The manufacturing method which can manufacture the optical film containing the resin layer which does not peel easily from a film can be provided.

Hereinafter, the present invention will be described in detail by way of embodiments and exemplifications. However, the present invention is not limited to the embodiments and examples shown below, and can be implemented with arbitrary modifications without departing from the scope of the claims of the present invention and the equivalents thereof.

In the following description, a "long" film refers to a film having a length of 5 times or more of the width, preferably 10 times or more, and more specifically, a roll shape. Film having a length that can be taken up and stored or transported. The upper limit of the ratio of the length to the width of the film is not particularly limited, and may be, for example, 100,000 times or less.

[1. Outline of production method of optical film]
The method for producing an optical film according to the present invention is a method for producing an optical film comprising a base film formed of a resin containing an alicyclic structure-containing polymer and a resin layer. This manufacturing method is
Forming a resin layer on the temporary support surface of the temporary support having a temporary support surface having a predetermined surface free energy, (I)
A step (II) of subjecting the film surface of the substrate film to a hydrophilic treatment such that the surface free energy of the film surface falls within a predetermined range;
Bonding the resin layer formed on the temporary support surface of the temporary support and the film surface subjected to the hydrophilic treatment of the base film (III),
Peeling the temporary support (IV), and
A step (V) of subjecting the resin layer and the base film to a heat treatment at a temperature above the glass transition temperature of the alicyclic structure-containing polymer,
including.

According to the said manufacturing method, the optical film containing the resin layer which does not peel easily from a base film and the said base film can be manufactured. Further, in the above manufacturing method, since it is possible to suppress that a part or all of the resin layer remains on the temporary support surface of the temporary support, smooth formation of the resin layer on the film surface of the base film is possible. .

In the step (III) of the above-mentioned production method, the resin layer and the film surface of the base film are usually directly bonded. Therefore, in the optical film, the base film and the resin layer are usually in direct contact with each other. Here, that the resin layer and the film surface of the base film are bonded "directly" means that there is no other layer between the resin layer and the film surface of the base film. Say. In addition, “directly in contact with” the base film and the resin layer means that there is no other layer between the base film and the resin layer.

Further, the step (V) may include the step (V-1) of stretching the base film. Furthermore, when the alicyclic structure-containing polymer contained in the substrate film has crystallinity, the step (V) includes the step (V-2) of advancing the crystallization of the alicyclic structure-containing polymer It may be

[2. Step (I) of forming a resin layer on the temporary support surface of the temporary support
The method for producing an optical film includes the step (I) of forming a resin layer on the temporary support surface of the temporary support. In this step (I), a temporary support having a temporary support surface having a predetermined surface free energy is generally prepared, and a resin layer is formed on the temporary support surface.

Surface free energy of the temporary support surface, usually 20 mJ / ^{m 2} or less, preferably less than 20 mJ / ^{m 2,} more preferably less than 19mJ / ^{m 2.} A temporary support surface having such low surface free energy has excellent releasability. Therefore, when peeling the temporary support body which has the said temporary support surface in process (IV), it is possible to suppress the remaining of the resin layer to a temporary support surface. The lower limit of the surface free energy of the temporary support surface is not particularly limited, and may be, for example, 10 mJ / m ² or more.

The surface free energy of a surface can be determined by measuring the contact angles of water and hexadecane to the surface and fitting the measured contact angles to the Owens Wendt model. The surface free energy can be specifically measured by the measurement method described in the examples.

A resin film is usually used as a temporary support. Among them, a long resin film is preferable from the viewpoint of efficiently producing an optical film by a roll-to-roll method. As this resin film, for example, a film formed of a resin material having a small surface free energy may be used. As a resin material with small surface free energy, resin containing polymers, such as an alicyclic structure containing polymer, a polyethylene terephthalate, polyethylene, a polybutylene terephthalate, a polypropylene, a polytetrafluoroethylene, etc. are mentioned, for example. Moreover, as this resin film, you may use the film in which the mold release process by the suitable mold release agent was given to the surface, for example.

The resin layer formed on the temporary support surface of the temporary support is formed of a resin of a type according to the characteristics required for the optical film. The resin for forming the resin layer is preferably at least one selected from the group consisting of a urethane resin, an olefin resin, a polyester resin, an epoxy resin and an acrylic resin. By using these resins, the resin layer can be made to function as an easily adhesive layer, so that an optical film excellent in adhesion to other members can be realized.

As a urethane resin, resin containing polyurethane or its crosslinked material can be used. Polyurethanes include, for example, polyurethanes derived from various polyols and polyisocyanates. Examples of the polyol include aliphatic polyester polyols obtained by the reaction of a polyol compound and a polybasic acid, polyether polyols, polycarbonate-based polyols, and any one of polyethylene terephthalate polyols; and mixtures thereof. Examples of the polyol compound include ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, glycerin and trimethylolpropane. As said polybasic acid, polyhydric carboxylic acids, such as polyhydric carboxylic acid containing dicarboxylic acid and tricarboxylic acid, or its anhydride, are mentioned, for example. Examples of dicarboxylic acids include adipic acid, succinic acid, sebacic acid, glutaric acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid and the like. As a tricarboxylic acid, a trimellitic acid etc. are mentioned, for example. Examples of the polyether polyols include poly (oxypropylene ether) polyols and poly (oxyethylene-propylene ether) polyols. In the polyurethane, for example, after the reaction of the polyol and the polyisocyanate, the unreacted hydroxyl group can be used as a polar group capable of the crosslinking reaction with the functional group in the crosslinking agent. The polyurethane is preferably a polycarbonate-based polyurethane derived from a polycarbonate-based polyol and a polyisocyanate and having a carbonate structure in its backbone. For the urethane resin, for example, the description in JP-A-2016-182568 can be referred to.

As polyurethane, what is contained in the water-based emulsion marketed as water-based urethane resin may be used. The water-based urethane resin is a composition containing polyurethane and water, and usually, polyurethane and optional components contained as necessary are dispersed in water. Examples of water-based urethane resins include "Adekabontiter" series manufactured by ADEKA, "Olester" series manufactured by Mitsui Chemicals, "Bondic" series manufactured by DIC, and "Hydran (WLS 201, WLS 202 etc.)" series , Bayer 's "Implanil" series, Kao' s "Poise" series, Sanyo Chemical Industries "Sanpren" series, Daiichi Kogyo Seiyaku 's "Superflex" series, Kushimoto Kasei " It is possible to use NEOREZ (Neo Reds) series, “Sancure” series manufactured by Lubrizol, and the like.

As the olefin resin, a resin containing an acid-modified polyolefin having a content of an unsaturated carboxylic acid component of 0.1% by weight to 10% by weight or a crosslinked product thereof can be used. Preferred examples of the olefin component which is the main component of the acid-modified polyolefin include ethylene, propylene, isobutylene, 2-butene, 1-butene, 1-pentene, alkenes such as 1-hexene and the like, and alkenes thereof A mixture is mentioned. Among them, from the viewpoint of enhancing the adhesion of the resin layer, alkenes having 2 to 4 carbon atoms such as ethylene, propylene, isobutylene and 1-butene are more preferable, ethylene and propylene are more preferable, and ethylene is particularly preferable. On the other hand, as an unsaturated carboxylic acid component which is a modifying component of acid-modified polyolefin, for example, half of acrylic acid, methacrylic acid, (anhydride) maleic acid, (anhydride) itaconic acid, fumaric acid, crotonic acid, unsaturated dicarboxylic acid Ester, half amide etc. are mentioned. Among them, acrylic acid, methacrylic acid and (anhydride) maleic acid are preferable, and acrylic acid and (anhydride) maleic acid are particularly preferable because they can enhance the adhesion of the resin layer and suppress cracking. The unsaturated carboxylic acid component is usually copolymerized in the acid-modified polyolefin, and the form is not particularly limited. The state of copolymerization includes, for example, random copolymerization, block copolymerization, graft copolymerization (graft modification) and the like. For the olefin resin, for example, the description in JP-A-2014-240174 can be referred to.

A commercial item may be used as acid-modified polyolefin. Examples of the commercially available product of the aqueous dispersion include “Arrow base (Arrow base SA-1200, Arrow base SB-1200, Arrow base SE-1200, Arrow base SB-1010” series (manufactured by UNITICA) and the like. Be

As polyester resin, resin containing polyester obtained by reaction of the said polyol compound and said polybasic acid or its crosslinked material can be used. In this polyester, for example, after completion of the reaction of the polyol compound and the polybasic acid, the unreacted hydroxyl group and carboxyl group can be used as a polar group capable of the crosslinking reaction with the crosslinking agent. In addition, the polyester may be obtained by copolymerizing a copolymer component having a polar group such as a hydroxyl group or a carboxyl group in combination with the above-mentioned polyol compound and polybasic acid. In addition, it is preferable that the polyester resin further contains an acrylic polymer in combination with the polyester or its crosslinked product in order to improve the adhesion of the resin layer. For the polyester resin, for example, the description in JP-A-2015-024511 can be referred to.

As polyester, a commercial item may be used. As a commercial item of the water-soluble or water-dispersible polyester, for example, "Nichigo Polyester (Nichigo Polyester W-0030, Nichigo Polyester W-0005 S30 WO, Nichigo Polyester WR-961 etc.)" series (manufactured by Nippon Synthetic Chemical Co., Ltd.) And “PES RESIN A (PES RESIN A-210, PES RESIN A-520, PES RESIN A-684G, PES RESIN A-695 GE, etc.)” series (manufactured by Takamatsu Yushi Co., Ltd.) and the like.

As the epoxy resin, any epoxy resin such as a one-component curing type epoxy resin or a two-component curing type epoxy resin can be used. Among them, those containing a water-soluble epoxy polymer are preferable. Preferred examples of water soluble epoxy polymers include polyamide epoxy polymers. This polyamide epoxy polymer is obtained, for example, by reacting epichlorohydrin with a polyamide polyamine obtained by the reaction of a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with a dicarboxylic acid such as adipic acid. As a commercial item of such a polyamide epoxy polymer, for example, Sumires resin 650 (30) and Sumires resin 675 manufactured by Sumika Chemtech Co., Ltd. can be mentioned. For the epoxy resin, for example, the description in JP-A-2008-26352 can be referred to.

When a water-soluble epoxy polymer is used, it is preferable to use a water-soluble polymer such as polyvinyl alcohol in combination in order to further improve the coatability. In this polyvinyl alcohol, not only partially saponified polyvinyl alcohol and completely saponified polyvinyl alcohol but also modified polyvinyl such as carboxyl group modified polyvinyl alcohol, acetoacetyl group modified polyvinyl alcohol, methylol group modified polyvinyl alcohol, amino group modified polyvinyl alcohol and the like Contains alcohol. As a commercial item of polyvinyl alcohol, "KL-318" which is an anionic group-containing polyvinyl alcohol manufactured by Kuraray Co., Ltd. can be mentioned.

As an acrylic resin, resin containing an acrylic polymer or its crosslinked material can be used. Moreover, as an acryl polymer, the homopolymer of an acryl monomer, the copolymer of two or more types of acryl monomers, the copolymer of one or more types of acryl monomers, and another monomer etc. are mentioned, for example. Further, examples of the acrylic monomer include acrylic acid, acrylic acid esters such as alkyl acrylates, acrylamides, acrylonitriles, methacrylic esters such as methacrylic acid and alkyl methacrylates, methacrylamides and methacrylonitriles. Among them, homopolymers and copolymers of acrylic monomers selected from the group consisting of acrylic acid esters and methacrylic acid esters are preferable. Particularly preferred examples include homopolymers and copolymers of acrylic monomers selected from the group consisting of acrylic acid esters and alkyl methacrylates having an alkyl group of 1 to 6 carbon atoms. In addition, an acrylic polymer is copolymerized with a copolymer component having a polar group such as a hydroxyl group or a carboxyl group in combination with the above-mentioned acrylic monomer so as to be able to react (crosslinking reaction) with a functional group possessed by a crosslinking agent. Is preferred. For the acrylic resin, for example, the description in JP-A-2015-024511 can be referred to.

In the above-mentioned resin layer, polymers such as polyurethane, polyolefin, polyester, epoxy polymer, acrylic polymer and the like may be crosslinked. When crosslinked, the above-mentioned polymer becomes a crosslinked product by reaction with a crosslinking agent. As a crosslinking agent used in this crosslinking, a compound having two or more functional groups capable of forming bonds by reacting with functional groups such as polar groups contained in a polymer can be used. An epoxy compound, a carbodiimide compound, an oxazoline compound, an isocyanate compound etc. are mentioned as an example of a crosslinking agent. Moreover, a crosslinking agent may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. Among them, epoxy compounds are preferable as the crosslinking agent.

As the epoxy compound, a polyfunctional epoxy compound having two or more epoxy groups in the molecule can be used. Thereby, a crosslinking reaction can be advanced and the mechanical strength of a resin layer can be improved effectively.

As the epoxy compound, one which is soluble in water or capable of being dispersed and emulsified in water is preferable from the viewpoint of ease of use. Examples of epoxy compounds include 1 mol of glycol such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexane glycol, neopentyl glycol, etc. And diepoxy compounds obtained by etherification with 2 moles of epichlorohydrin; polyesters obtained by etherification with 1 mole or more of epichlorohydrin and 1 mole of polyhydric alcohol such as glycerin, polyglycerin, trimethylolpropane, pentaerythritol, and sorbitol Epoxy compound; diepoxy obtained by esterification of 1 mole of dicarboxylic acid such as phthalic acid, terephthalic acid, oxalic acid, adipic acid and the like with 2 moles of epichlorohydrin Compounds; and the like.

More specifically, as the epoxy compound, 1,4-bis (2 ′, 3′-epoxypropyloxy) butane, 1,3,5-triglycidyl isocyanurate, 1,3-diglycidyl-5- (γ-) Acetoxy-β-oxypropyl) isocyanurate, sorbitol polyglycidyl ethers, polyglycerol polyglycidyl ethers, pentaerythritol polyglycidyl ethers, diglycerol polyglycidyl ether, 1,3,5-triglycidyl (2-hydroxyethyl) isocyanate Epoxy compounds such as nurate, glycerol polyglycerol ethers and trimethylolpropane polyglycidyl ethers are preferred. As an example of the specific commercial item, "Denacol (Denacol EX-521, EX-614B etc.)" manufactured by Nagase ChemteX can be mentioned.

Furthermore, the resin which forms a resin layer may be combined with the polymer mentioned above or its crosslinked material, and may further contain arbitrary components. Optional components include, for example, curing accelerators, curing assistants, particles, heat stabilizers, weathering stabilizers, leveling agents, surfactants, antioxidants, antistatic agents, slip agents, antiblocking agents, antifogging agents. Agents, lubricants, dyes, pigments, natural oils, synthetic oils, waxes and the like. One of the optional components may be used alone, or two or more of the optional components may be used in combination at an optional ratio.

The resin forming the resin layer may be one type or two or more types. Thus, for example, the above-described urethane resin, olefin resin, polyester resin, epoxy resin and acrylic resin may be used in combination of two or more. For example, a resin containing a combination of a polyurethane and an acid-modified polyolefin may be used, or a resin containing a combination of a polyester and an acrylic polymer may be used.

The thickness of the resin layer can be set arbitrarily according to the application of the resin layer. For example, the thickness of the resin layer which can function as an easily adhesive layer is preferably 10 nm or more, more preferably 30 nm or more, particularly preferably 50 nm or more, preferably 5 μm or less, more preferably 2 μm or less, particularly preferably 1 μm or less is there. By making thickness of an easily bonding layer more than the said lower limit, an optical film can be bonded together with another member by sufficient adhesive strength. Further, by setting the thickness of the easily bonding layer to the upper limit value or less, the occurrence of deformation of the easily bonding layer to be a relatively soft layer is suppressed, and it becomes easy to wind the optical film as a roll. Moreover, when the thickness of the easily bonding layer is in the above range, sufficient adhesion between the base film and the easily bonding layer can be obtained, and the thickness of the optical film can be reduced.

The formation of the resin layer on the temporary support surface of the temporary support can be performed, for example, by a coating method. In this coating method, a coating liquid containing a component such as a polymer contained in a resin forming a resin layer or a precursor thereof is generally coated on a temporary supporting surface, and the coated coating liquid is cured. . In this coating method, usually, the coating liquid can be a resin layer as it is. Or, in this coating method, the coating liquid can usually become a resin layer through the reaction of the components contained therein, the volatilization of the solvent, and the like as necessary. Thereby, a resin layer can be obtained as a layer of resin which contains a part or all of the component contained in the coating liquid, or its reaction product.

The amount of the polymer such as polyurethane or its precursor in the coating liquid is preferably 60% by weight to 100% by weight, more preferably 70% by weight to 100% by weight of the total solid content in the coating liquid. It is weight%.

When the coating liquid contains a crosslinking agent, the amount of the crosslinking agent is usually 0.1 parts by weight or more, preferably 1 part by weight, based on 100 parts by weight of the polymer in the coating liquid and the precursor thereof. The amount is more preferably 2 parts by weight or more, and usually 20 parts by weight or less, preferably 15 parts by weight or less, more preferably 10 parts by weight or less. By setting the amount of the crosslinking agent to the lower limit value or more of the above range, the crosslinking reaction proceeds sufficiently, so that the mechanical strength of the resin layer can be appropriately improved, and the amount of the crosslinking agent is set to the upper limit value or less. As a result, the remaining amount of unreacted crosslinking agent can be reduced, and the mechanical strength of the resin layer can be appropriately improved.

The coating liquid may contain a solvent, if necessary. Examples of the solvent include water; organic solvents such as methanol, ethanol, isopropyl alcohol, acetone, tetrahydrofuran, N-methylpyrrolidone, dimethyl sulfoxide, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, methyl ethyl ketone and triethylamine. Moreover, a solvent may be used individually by 1 type, and may be used combining 2 or more types by arbitrary ratios. Among them, water is preferred as the solvent. As a preferred example, the coating liquid may be an aqueous emulsion in which the concentration of the organic solvent is less than 1% by weight. The amount of the solvent is preferably set appropriately so that the viscosity of the coating liquid is in a range suitable for coating.

Examples of the coating method of the coating liquid include wire bar coating method, dip method, spray method, spin coating method, roll coating method, gravure coating method, air knife coating method, curtain coating method, slide coating method, extrusion The coat method etc. are mentioned.

In addition, in the method of forming the resin layer on the temporary support surface of the temporary support, an optional step may be performed after the coating liquid is applied to the temporary support surface. For example, when the coating liquid contains a solvent, the coating liquid may be dried to remove the solvent. Also, for example, when the crosslinking solution contains a crosslinking agent, the crosslinking may be performed by the crosslinking agent. Methods of drying and crosslinking are optional. For example, drying may be any method such as vacuum drying, heat drying and the like. Among them, it is preferable to cure the coating liquid by heating and drying, from the viewpoint of rapidly advancing a reaction such as a crosslinking reaction with the drying. When the coating liquid is cured by heating, the heating temperature can be appropriately set within a range in which the coating liquid can be dried to remove the solvent and at the same time the solid content in the coating liquid can be cured.

[3. Process of subjecting the film surface of the base film to hydrophilic treatment (II)]
The method for producing an optical film includes the step (II) of subjecting the film surface of the base film to a hydrophilic treatment. In this step (II), a base film formed of a resin containing an alicyclic structure-containing polymer is usually prepared, and the film surface of the base film is subjected to a hydrophilic treatment.

The alicyclic structure-containing polymer is a polymer having an alicyclic structure in the molecule. The alicyclic structure-containing polymer is usually excellent in mechanical strength, transparency, dimensional stability and lightness, and further low in hygroscopicity. As such an alicyclic structure containing polymer, the polymer which can be obtained by the polymerization reaction which used cyclic olefin as a monomer, or its hydrogenated substance etc. are mentioned, for example. Moreover, as said alicyclic structure containing polymer, any of the polymer which contains an alicyclic structure in a principal chain, and the polymer which contains an alicyclic structure in a side chain can be used. As an alicyclic structure, although a cycloalkane structure, a cycloalkene structure, etc. are mentioned, a cycloalkane structure is preferable from a viewpoint of heat stability etc., for example.

The number of carbon atoms contained in one alicyclic structure is preferably 4 or more, more preferably 5 or more, more preferably 6 or more, preferably 30 or less, more preferably 20 or less, Particularly preferably, it is 15 or less. When the number of carbon atoms contained in one alicyclic structure is in the above range, mechanical strength, heat resistance, and formability are highly balanced.

The proportion of the structural unit having an alicyclic structure in the alicyclic structure-containing polymer is preferably 30% by weight or more, more preferably 50% by weight or more, still more preferably 70% by weight or more, particularly preferably 90% by weight It is above. The flexibility and heat resistance of the optical film can be enhanced by increasing the proportion of structural units having an alicyclic structure as described above.
In addition, in the alicyclic structure-containing polymer, the balance other than the structural unit having an alicyclic structure is not particularly limited, and may be appropriately selected depending on the purpose of use.

As the alicyclic structure-containing polymer, either one having crystallinity or one having no crystallinity may be used, or both may be used in combination. Here, the polymer having crystallinity means a polymer having a melting point Mp. That is, the polymer having crystallinity refers to a polymer whose melting point Mp can be observed by a differential scanning calorimeter (DSC). By using an alicyclic structure-containing polymer having crystallinity, the impact strength, solvent resistance, diffraction resistance and tear strength of the optical film can be particularly enhanced. Moreover, the manufacturing cost of an optical film can be reduced by using the alicyclic structure containing polymer which does not have crystallinity.

Examples of the crystalline alicyclic structure-containing polymer include the following polymers (α) to (6). Among these, a polymer (β) is preferable as the alicyclic structure-containing polymer having crystallinity since an optical film excellent in flexibility, heat resistance and folding resistance is easily obtained.
Polymer (α): A ring-opening polymer of a cyclic olefin monomer, which has crystallinity.
Polymer (β): A hydrogenated substance of the polymer (α) and having crystallinity.
Polymer (γ): Addition polymer of cyclic olefin monomer, which has crystallinity.
Polymer (δ): A hydrogenated substance of polymer (γ) or the like, which has crystallinity.

Specifically, as the alicyclic structure-containing polymer having crystallinity, a ring-opened polymer of dicyclopentadiene which has crystallinity, and a hydrogenated product of the ring-opened polymer of dicyclopentadiene Those having crystallinity are more preferable, and those which are a hydrogenated product of a ring-opening polymer of dicyclopentadiene and have crystallinity are particularly preferable. Here, the ring-opened polymer of dicyclopentadiene means that the ratio of structural units derived from dicyclopentadiene to the total structural units is usually 50% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight or more. More preferably, it refers to 100% by weight of a polymer.

The hydride of the ring-opened polymer of dicyclopentadiene preferably has a high ratio of racemo dyads. Specifically, the ratio of racemo / dyad of the repeating unit in the hydride of the ring-opened polymer of dicyclopentadiene is preferably 51% or more, more preferably 60% or more, and particularly preferably 65% or more. The high ratio of racemo dyad indicates that syndiotactic stereoregularity is high. Thus, the higher the proportion of racemo dyads, the higher the melting point of the hydride of the ring-opened polymer of dicyclopentadiene.
The ratio of racemo dyads can be determined based on ¹³ C-NMR spectral analysis described in the examples below.

A resin containing an alicyclic structure-containing polymer having a high degree of crystallinity is usually excellent in properties such as flexibility, heat resistance, bending resistance, solvent resistance and the like. Therefore, it is preferable that the alicyclic structure containing polymer which has crystallinity which is contained in an optical film has high crystallinity degree. However, the surface of the base film containing the alicyclic structure-containing polymer having a high degree of crystallinity is poor in adhesion to other resins. Therefore, the progress of crystallization is preferably performed after the resin layer is bonded to the base film, and therefore, at the time before step (V), the alicyclic resin contained in the resin forming the base film It is preferable that the crystallinity degree of a formula structure containing polymer is low. Therefore, it is preferable that the crystallinity degree of the alicyclic structure-containing polymer contained in the base film is low before the film surface is subjected to the hydrophilic treatment in the step (II). Specifically, the crystallinity of the alicyclic structure-containing polymer having crystallinity contained in the base film is preferably less than 3%, more preferably 2 before the film surface is subjected to a hydrophilic treatment. It is less than%, particularly preferably less than 1%.

A crystallinity degree is a parameter | index which shows the ratio of what was crystallized among the alicyclic structure containing polymers which have crystallinity contained in a base film. The crystallinity of the alicyclic structure-containing polymer having crystallinity contained in the base film can be measured by X-ray diffraction. Specifically, the crystallinity can be measured by the measurement method described in the examples.

The melting point Mp of the crystalline alicyclic structure-containing polymer is preferably 200 ° C. or more, more preferably 230 ° C. or more, and preferably 290 ° C. or less. By using an alicyclic structure-containing polymer having such a melting point Mp and crystallinity, an optical film further excellent in the balance between moldability and heat resistance can be obtained.

The alicyclic structure-containing polymer having crystallinity as described above can be produced, for example, by the method described in WO 2016/067893.

On the other hand, the alicyclic structure-containing polymer having no crystallinity is, for example, (1) a norbornene polymer, (2) a cyclic olefin polymer of a single ring, (3) a cyclic conjugated diene polymer, (4) And vinyl alicyclic hydrocarbon polymers and hydrides thereof. Among these, from the viewpoint of transparency and moldability, norbornene polymers and their hydrides are more preferable.

Examples of norbornene polymers include ring-opening polymers of norbornene monomers, ring-opening copolymers of norbornene monomers and other monomers capable of ring-opening copolymerization, and hydrides thereof; addition polymers of norbornene monomers, And addition copolymers of norbornene monomers with other monomers copolymerizable, and the like. Among these, from the viewpoint of transparency, a hydrogenated ring-opened polymer of a norbornene monomer is particularly preferable.
As the above-mentioned alicyclic structure-containing polymer, for example, those described in JP-A-2002-321302 can be arbitrarily selected and used.

The alicyclic structure-containing polymer may be used alone or in combination of two or more at an arbitrary ratio.

The glass transition temperature Tg of the alicyclic structure-containing polymer is preferably 80 ° C. or more, more preferably 85 ° C. or more, still more preferably 90 ° C. or more, preferably 250 ° C. or less, more preferably 170 ° C. or less . An alicyclic structure-containing polymer having a glass transition temperature in such a range is resistant to deformation and stress during use at high temperatures, and is excellent in durability.

The weight average molecular weight (Mw) of the alicyclic structure-containing polymer is preferably 1,000 or more, more preferably 2,000 or more, still more preferably 10,000 or more, particularly preferably 25,000 or more, and preferably Is 1,000,000 or less, more preferably 500,000 or less, still more preferably 100,000 or less, particularly preferably 80,000 or less, particularly preferably 50,000 or less. A polymer having such a weight average molecular weight is excellent in the balance between moldability and heat resistance.

The molecular weight distribution (Mw / Mn) of the alicyclic structure-containing polymer is preferably 1.0 or more, more preferably 1.2 or more, particularly preferably 1.5 or more, preferably 10 or less, more preferably It is 4.0 or less, more preferably 3.5 or less. Here, Mn represents a number average molecular weight. An alicyclic structure-containing polymer having such a molecular weight distribution is excellent in molding processability.

The weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) can be measured as a polystyrene conversion value by gel permeation chromatography (GPC) using tetrahydrofuran as a developing solvent.

The proportion of the alicyclic structure-containing polymer in the resin forming the substrate is preferably 50% by weight or more, more preferably 70% by weight or more, still more preferably 80% by weight or more, and particularly preferably 90% by weight or more is there. By setting the ratio of the alicyclic structure-containing polymer to the lower limit value of the above range or more, the excellent characteristics of the alicyclic structure-containing polymer can be exhibited effectively.

The resin forming the base material may further contain optional components in combination with the alicyclic structure-containing polymer. Optional components include, for example, antioxidants such as phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants; light stabilizers such as hindered amine-based light stabilizers; petroleum-based wax, Fischer-Tropsch wax, Wax such as polyalkylene wax; sorbitol type compound, metal salt of organic phosphoric acid, metal salt of organic carboxylic acid, nucleating agent such as kaolin and talc; diaminostilbene derivative, coumarin derivative, azole type derivative (eg, benzoxazole derivative, Fluorescent brighteners such as benzotriazole derivatives, benzimidazole derivatives, and benzothiasol derivatives), carbazole derivatives, pyridine derivatives, naphthalic acid derivatives, and imidazolone derivatives; benzophenone type ultraviolet absorbers, salicylic acid type ultraviolet absorbers, benzotriazole type UV absorbers such as external radiation absorbers; inorganic fillers such as talc, silica, calcium carbonate, glass fibers; colorants; flame retardants; flame retardant aids; antistatic agents; plasticizers; near infrared absorbers; Optional polymers other than alicyclic structure-containing polymers such as soft polymers; and the like. In addition, as the optional components, one type may be used alone, or two or more types may be used in combination at an optional ratio.

The base film preferably has a high total light transmittance. Specifically, the total light transmittance of the base film is preferably 80% or more, more preferably 85% or more, and particularly preferably 88% or more. The total light transmittance can be measured in the wavelength range of 400 nm to 700 nm using an ultraviolet and visible spectrometer.

The base film preferably has a small haze. Specifically, the haze of the substrate film is preferably less than 3.0%, more preferably less than 2.0%, particularly preferably less than 1.0%, and ideally 0%. The haze can be measured using a haze meter.

The thickness of the substrate film is preferably 5 μm or more, more preferably 10 μm or more, particularly preferably 15 μm or more, preferably 200 μm or less, more preferably 100 μm or less, particularly preferably 50 μm or less. The mechanical strength of an optical film can be raised by making thickness of a substrate film more than the above-mentioned lower limit. The thickness of an optical film can be made thin by making the thickness of a base film below the said upper limit.

The base film can be produced by forming a resin containing an alicyclic structure-containing polymer into a film by any forming method. Examples of molding methods include injection molding, melt extrusion molding, press molding, inflation molding, blow molding, calendar molding, cast molding and compression molding. Among these, the melt extrusion molding method is preferable because control of the thickness is easy.

When manufacturing a base film by the melt-extrusion method, the conditions for extrusion are preferably as follows. The cylinder temperature (molten resin temperature) is preferably (Tg + 80 ° C) or more, more preferably (Tg + 100 ° C) or more, preferably (Tg + 180 ° C) or less, more preferably (Tg + 150 ° C) or less. Further, when using an alicyclic structure-containing polymer having crystallinity in particular, the cylinder temperature is preferably Tm or more, more preferably (Tm + 20 ° C.) or more, preferably (Tm + 100 ° C.) or less, more preferably Tm + 50 ° C) or less. Furthermore, the cast roll temperature is preferably (Tg-30 ° C.) or higher, preferably Tg or lower, more preferably (Tg-15 ° C.) or lower. By producing a base film under such conditions, a base film having a preferable thickness can be easily produced. Here, "Tm" represents the melting point of the alicyclic structure-containing polymer, and "Tg" represents the glass transition temperature of the alicyclic structure-containing polymer.

After preparing the substrate film, the film surface of the substrate film is subjected to a hydrophilic treatment. In the case of forming a resin layer on one film surface of the base film, the one film surface is subjected to a hydrophilic treatment. Moreover, when forming a resin layer in both the film surfaces of a base film, a hydrophilic process is given to the both film surface. By applying such hydrophilic treatment, the surface free energy of the film surface of the base film is adjusted to a predetermined range.

Specific surface free energy of the film surface of the substrate film after the hydrophilic treatment is usually 40 mJ / ^{m 2} or more, preferably 50 mJ / ^{m 2} or more, particularly preferably 60 mJ / ^{m 2} or more. When the film surface of the base film has such a high surface free energy, the resin layer can be stably fixed to the film surface. Therefore, when the temporary support is peeled off in step (IV), this temporary support It is possible to suppress the remaining of the resin layer on the temporary support surface of The upper limit of the surface free energy of the film surface is not particularly limited, and may be, for example, 77 mJ / m ² or less.

The hydrophilic treatment is preferably at least one selected from the group consisting of corona treatment, plasma treatment and excimer treatment. In addition, these treatments may be performed singly or in combination of two or more. By subjecting the film surface of the base film to these treatments, usually, a hydrophilic group such as a hydroxyl group, a carboxyl group or a carbonyl group is formed on the film surface. Thereby, the surface free energy of the film surface can be improved.

The processing conditions of the above-mentioned hydrophilic processing are suitably set up so that the surface free energy of the film side of a substrate film can be put into a desired range. Although specific processing conditions differ according to the kind of base film, and a processing apparatus, they can be set as follows, for example.

In corona treatment, the film surface is usually treated by applying a high voltage at high frequency between the dielectric and the insulated electrode to generate a corona and passing the substrate film between the dielectric and the electrode. . In general, the surface free energy of the film surface subjected to the corona treatment is adjusted in accordance with the type of electrode, electrode spacing, voltage, humidity, and type of substrate film to be treated. The distance between the electrode and the substrate film is preferably 1 mm to 5 mm, and more preferably 1 mm to 3 mm. The conveyance speed of the substrate film to be subjected to the corona treatment is preferably 0.01 m / min to 10 m / min, and more preferably 0.05 m / min to 5 m / min. The electrode width is preferably 0.1 m to 1 m. The corona output is preferably 100 W or more, and preferably 3 kW or less, more preferably 1.5 kW or less from the viewpoint of suppressing scratching of the base film. The treatment intensity calculated by “treatment intensity = (output) / (conveyance speed × electrode width)” in the corona treatment performed while conveying the base film is preferably 4.2 kW · min / m ² or more.

In the plasma treatment, the film surface of the base film is usually treated by performing plasma discharge in a gas atmosphere such as an inert gas and an oxygen gas. This plasma processing may be performed under a reduced pressure of, for example, about 0.1 Torr to 1 Torr, but is preferably performed under atmospheric pressure from the viewpoint of performing the processing efficiently while transporting the base film. Examples of the type of gas used in plasma treatment include nitrogen; oxygen; rare gases such as argon and helium; acrylic acid; hydroxyalkyl; fluorine-based compounds such as CF ₄ , CHF ₃ and C ₂ F ₆ ; . A preferable gas is, for example, a mixed gas in which an inert gas such as nitrogen and oxygen are mixed in a ratio of 95.0: 5.0 to 99.9: 0.1. The distance between the electrode and the substrate film is preferably 1 mm to 5 mm, and more preferably 1 mm to 3 mm. The transport speed of the substrate film to be subjected to the plasma treatment is preferably 1 m / min to 70 m / min, and more preferably 3 m / min to 50 m / min. The electrode width is preferably 0.1 m to 1 m. The plasma output is preferably 50 W or more. The frequency range is preferably 10 kHz to 100 kHz. The processing strength calculated by “processing strength = (output) / (conveyance speed × electrode width)” in the plasma processing performed while transporting the base film is preferably 0.028 kW · min / m ² or more.

In the excimer treatment, the film surface of the base film is usually treated by irradiating light having a central wavelength of less than 180 nm using an excimer lamp. The lower limit of the central wavelength of the light to be irradiated is not particularly limited, and may be, for example, 100 nm or more. Here, "the central wavelength of light" refers to a wavelength that brings about the maximum emission intensity in the emission spectrum. In excimer processing, light of a target central wavelength can be obtained by selecting the type of excimer lamp. For example, the central wavelength of light irradiated from an Ar excimer lamp is 126 nm, the central wavelength of light irradiated from a Kr excimer lamp is 146 nm, and the central wavelength of light irradiated from an ArBr excimer lamp is 165 nm, The central wavelength of the light emitted from the Xe excimer lamp is 172 nm, and the central wavelength of the light emitted from the ArCl excimer lamp is 175 nm. The light irradiation time is 0.1 seconds to 150 seconds, preferably 1 second to 120 seconds, and more preferably 10 seconds to 90 seconds. The illuminance is preferably 50 mW / cm ² or more. The distance between the excimer lamp and the substrate film is preferably 10 mm or less.

[4. Step of bonding the base film and the resin layer (III)]
A step (III) of bonding the resin layer formed on the temporary support surface of the temporary support after the step (I) and the step (II) with the film surface of the base film subjected to the hydrophilic treatment I do. In this step (III), usually, the resin layer and the film surface of the base film are directly bonded without interposing another layer such as an adhesive layer.

From the viewpoint of preventing air bubbles from remaining between the resin layer and the base film, the bonding is preferably performed so that the resin layer and the base film are pressed to each other. For example, the resin layer and the base film are brought into pressure contact with each other by passing the temporary support having the resin layer formed on the temporary support surface and the base film between the pair of nip rolls, and bonding is performed. Good.

The bonding is usually performed at a temperature lower than the crystallization start temperature of the alicyclic structure-containing polymer contained in the resin forming the base film. From the viewpoint of reducing the energy for heating and suppressing the manufacturing cost, the bonding is preferably performed at normal temperature.

[5. Step of peeling off the temporary support (IV)]
After step (III), step (IV) of peeling off the temporary support is performed. When the surface free energy of the film surface of the substrate film is in the above-described range, the resin layer can be stably fixed to the film surface of the substrate film. In addition, when the surface free energy of the temporary support surface of the temporary support is in the above-described range, the resin layer can be smoothly separated from the temporary support surface of the temporary support. Therefore, the temporary support is peeled off smoothly. Therefore, it is possible to make it difficult to cause part or all of the resin layer to remain on the temporary support surface of the temporary support to be peeled off.
By peeling off the temporary support, a multilayer film comprising a base film and a resin layer is obtained.

[6. Step of heat treating the base film and the resin layer (V)]
After the step (IV), a step (V) of subjecting the resin layer and the base film to heat treatment is performed. The heat treatment temperature is set above the glass transition temperature of the alicyclic structure-containing polymer contained in the base film. At such a heat treatment temperature, the adhesion between the resin layer and the base film is enhanced, and an optical film including a base film and a resin layer which is not easily peeled off from the base film can be produced.

When the resin contained in the resin layer has a glass transition temperature, the glass transition temperature of the resin contained in the resin layer is usually lower than the glass transition temperature of the alicyclic structure-containing polymer contained in the base film. Therefore, the heat treatment temperature in the step (V) is usually higher than the glass transition temperature of the resin contained in the resin layer. When the glass transition temperature of the resin contained in the resin layer is higher than the glass transition temperature of the alicyclic structure-containing polymer contained in the base film, the adhesion between the resin layer and the base film is effective. From the viewpoint of enhancing the heat treatment temperature, it is preferable to set the heat treatment temperature in the step (V) to a temperature higher than the glass transition temperature of the resin contained in the resin layer.

The specific heat treatment temperature is preferably (Tg + 30 ° C) or more, more preferably (Tg + 50 ° C) or more, particularly preferably (Tg + 70 ° C) or more, preferably (Tg + 120 ° C) or less, more preferably (Tg + 110 ° C) Or less, particularly preferably (Tg + 100 ° C.) or less. When the heat treatment temperature is at least the lower limit value of the above range, the adhesion between the resin layer and the base film can be effectively enhanced. Moreover, the cloudiness of a base film can be suppressed because heat processing temperature is below the upper limit of the said range. Here, “Tg” represents the glass transition temperature of the alicyclic structure-containing polymer contained in the base film.

The processing time to which the above-mentioned heat treatment is performed can be arbitrarily set in the range which can raise the adhesion nature of a resin layer and a substrate film. The specific treatment time is preferably 5 seconds or more, more preferably 15 seconds or more, and particularly preferably 30 seconds or more. By making processing time or more the lower limit value of the said range, the adhesiveness of a resin layer and a base film can be improved effectively. The upper limit of the treatment time is not particularly limited, but may be, for example, 5 minutes or less.

Step (V) may optionally include step (V-1) of stretching the base film. In this step (V-1), the substrate film is stretched by stretching the multilayer film provided with the substrate film and the resin layer. Usually, this stretching is performed at temperature conditions equal to or higher than the glass transition temperature of the alicyclic structure-containing polymer contained in the base film. Therefore, in the step (V-1), both the heat treatment on the resin layer and the base film and the stretching process on the base film can be performed.

There is no particular limitation on the method of stretching the base film, and any stretching method may be used. Examples of stretching methods include uniaxial stretching methods such as a method of uniaxially stretching a base film in the longitudinal direction (longitudinal uniaxial stretching method), a method of uniaxially stretching a base film in the width direction (horizontal uniaxial stretching method), etc .; Material film is simultaneously stretched in the longitudinal direction and simultaneously in the width direction, and biaxial stretching such as sequential biaxial stretching method in which the base film is stretched in one of the longitudinal direction and the width direction and then stretched in the other And a method (oblique stretching method) of stretching the substrate film in an oblique direction which is neither parallel nor perpendicular to the width direction, such as more than 0 ° and less than 90 ° with respect to the width direction. As such a stretching method, for example, the method described in WO 2016/067893 can be used.

The stretching temperature in the step (V-1) is preferably Tg ° C. or higher, preferably (Tg + 60 ° C.) or lower, more preferably (Tg + 50 ° C.) or lower. By performing stretching in such a temperature range, polymer molecules contained in the base film can be appropriately oriented. Here, “Tg” represents the glass transition temperature of the alicyclic structure-containing polymer contained in the base film.

The draw ratio in the step (V-1) can be appropriately selected according to the attributes such as optical properties, thickness and strength obtained after drawing, and is usually 1.1 times or more, usually 10 times or less, preferably 5 times or less. Here, when drawing is performed in a plurality of different directions as in, for example, a biaxial drawing method, the drawing ratio is the total drawing ratio represented by the product of the drawing ratio in each drawing direction. By setting the draw ratio to the upper limit value or less of the above range, the possibility of breakage of the film can be reduced, so that the optical film can be easily manufactured.

By subjecting the base film to the above-described stretching treatment in the step (V-1), an optical film having desired properties can be obtained.

A process (V) is a process which advances crystallization of the alicyclic structure containing polymer contained in a base film as needed, when a base film contains the alicyclic structure containing polymer which has crystallinity. (V-2) may be included. At this process (V-2), a base film is heated to predetermined temperature by heating a multilayer film provided with a base film and a resin layer, and crystallization of an alicyclic structure-containing polymer is advanced. . Usually, the progress of crystallization of the alicyclic structure-containing polymer is carried out under the temperature condition higher than the glass transition temperature of the alicyclic structure-containing polymer contained in the base film. Therefore, in the step (V-2), both of the heat treatment to the resin layer and the base film, and the crystallization treatment of the alicyclic structure-containing polymer contained in the base film can be performed. In addition, when the step (V) includes the step (V-1) of stretching the substrate film, the step (V-2) of advancing the crystallization of the alicyclic structure-containing polymer is usually a step (V-) It takes place after 1).

The crystallization is preferably carried out in a tensioned state while holding at least two side edges of the multilayer film including the base film. The state in which the multilayer film is in tension means a state in which the multilayer film is in tension. However, the state in which the multilayer film is in tension does not include the state in which the multilayer film is substantially stretched. Further, being substantially stretched means that the stretching ratio in any direction of the multilayer film is usually 1.1 or more. In the tensioned state in which at least two edges of the multilayer film are held, deformation due to heat shrinkage of the multilayer film is prevented in the region between the held edges. Therefore, crystallization can be advanced without impairing the smoothness of the film.

In order to prevent deformation in a large area of the multilayer film, the edges including the opposing two edges of the multilayer film should be held to tension the area between the held edges. Is preferred. For example, in a rectangular sheet-fed multilayer film, two opposing end sides (for example, the end sides on the long side or the end sides on the short side) are held and between the two end sides By making the area of the film in tension, deformation can be prevented on the entire surface of the sheet-fed multilayer film. Further, in a long multilayer film, the two end sides at the end in the width direction (that is, the end sides on the long side) are held to tension the region between the two end sides. Thus, deformation can be prevented on the entire surface of the long multilayer film. Thus, in the multilayer film in which the deformation is prevented, the occurrence of deformation such as wrinkles is suppressed even if stress is generated in the film due to heat contraction. In the case of using a film subjected to a stretching treatment as the multilayer film, the deformation is suppressed more by holding at least two sides which are orthogonal to the stretching direction (the direction in which the stretching ratio is large in the case of biaxial stretching). It will be reliable. As such a holder, for example, the one described in WO 2016/067893 can be used.

In the step (V-2), as described above, the temperature of the base film is adjusted to a predetermined treatment temperature to promote crystallization of the alicyclic structure-containing polymer contained in the base film. At this time, the specific treatment temperature is usually Tg or more, preferably (Tg + 20 ° C) or more, more preferably (Tg + 30 ° C) or more, and usually Tm or less, preferably (Tm-20 ° C) or less, more preferably (Tm-40 ° C.) or less. Here, “Tm” represents the melting point of the crystalline alicyclic structure-containing polymer contained in the substrate film, and “Tg” represents the crystalline alicyclic structure-containing polymer contained in the substrate film Represents the glass transition temperature of the polymer. When the treatment temperature is at least the lower limit value of the above range, crystallization of the alicyclic structure-containing polymer can be efficiently advanced. Moreover, the cloudiness of a base film can be suppressed because process temperature is below the upper limit of the said range.

In the step (V-2), the treatment time for maintaining the temperature of the substrate film in the above temperature range is preferably 1 second or more, more preferably 5 seconds or more, preferably 30 minutes or less, more preferably 10 It is less than a minute. When the processing time is at least the lower limit value of the above range, crystallization of the alicyclic structure-containing polymer having crystallinity can be sufficiently advanced, and therefore, the flexibility, heat resistance and bending resistance of the optical film Etc. can be enhanced. Moreover, the cloudiness of a base film can be suppressed by processing time being below the upper limit of the said range.

By subjecting the substrate film to the above-described crystallization treatment in the step (V-2), the crystallinity of the alicyclic structure-containing polymer having crystallinity contained in the substrate film can be increased. An optical film excellent in properties such as flexibility, heat resistance, folding resistance, solvent resistance and the like can be obtained.

[7. Optional process]
The method for producing an optical film may further include an optional step in combination with the above-described step.
As an optional step, for example, after the step (V-2), there is a relaxation step in which the base film is heat shrunk to remove the residual stress.

Moreover, as an arbitrary process, the process of providing arbitrary layers other than a base film and a resin layer in an optical film is mentioned, for example. The optional layer is usually provided on the side of the substrate film opposite to the resin layer. Examples of the optional layer include a conductive layer, an antireflective layer, a hard coat layer, an antistatic layer, an antiglare layer, an antifouling layer, a separator film layer and the like.

[8. Optical film]
According to the manufacturing method mentioned above, it is possible to obtain an optical film including a base film and a resin layer which is formed on the film surface of the base film and hardly peels off from the base film. In this optical film, the base film is subjected to a stretching treatment, the base film contains a crystalline structure-containing alicyclic structure-containing polymer, and further, crystals of the above-described alicyclic structure-containing polymer The adhesion between the substrate film and the resin layer can be increased even if the conversion progresses.

In this optical film, the resin layer may be formed only on one film surface of the substrate film, or may be formed on both film surfaces of the substrate film. An optical film having a resin layer on both film surfaces of the base film can form both resin layers simultaneously. For example, the steps (II) to (V) described above can be simultaneously performed on both film surfaces of the base film to simultaneously form two resin layers. Therefore, since it is not necessary to form a resin layer one by one like formation of the resin layer by a coating method, reduction of the number of processes and shortening of manufacturing time can be performed, and manufacturing cost can be suppressed.

Since an optical film contains the base film formed with resin containing an alicyclic structure containing polymer, it can exhibit the outstanding characteristic which an alicyclic structure containing polymer shows. Therefore, the optical film is usually excellent in mechanical strength, transparency, dimensional stability and lightness, and further has low hygroscopicity. In addition, when an alicyclic structure-containing polymer having crystallinity is used, the optical film further has flexibility, heat resistance, bending resistance, low water absorption, etc. in addition to the above excellent properties. Excellent in the characteristics of

Among them, from the viewpoint of making the characteristics such as flexibility, heat resistance, folding resistance, low water absorption and the like particularly good, the alicyclic structure-containing polymer having crystallinity in the base film included in the optical film is It is preferable to have a high degree of crystallinity. The specific range of the degree of crystallinity is preferably 10% or more, more preferably 15% or more, still more preferably 30% or more, particularly preferably 50% or more, particularly preferably 60% or more. Such a high degree of crystallinity can be achieved by promoting the crystallization of the alicyclic structure-containing polymer in step (V). The upper limit of the degree of crystallinity is ideally 100%, but may usually be 90% or less, or 80% or less.

Moreover, since an optical film contains a resin layer, it can exhibit the outstanding characteristic based on a resin layer. For example, an optical film including an easy adhesion layer as a resin layer can exhibit excellent adhesion on the side of the easy adhesion layer. Therefore, it is possible to adhere the optical film with high adhesive strength to the other member via the adhesive or the pressure-sensitive adhesive on the side of the easy adhesion layer.

The optical film preferably has a high total light transmittance. Specifically, the total light transmittance of the optical film is preferably within the same range as described above as the range of the total light transmittance of the base film.

The optical film preferably has a small haze. Specifically, the haze of the optical film is preferably within the same range as described above as the range of the haze of the base film.

The optical film can be optionally applied to optical applications, and can be used, for example, as a component of a display device. Among them, the optical film is preferably used as a component of a touch sensor of a liquid crystal display device by utilizing its excellent heat resistance and mechanical strength (in particular, flexibility). In particular, an optical film provided with a base film containing a crystalline alicyclic structure-containing polymer is excellent in bending resistance, and thus is applicable to a flexible display device and is preferable.

Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to the embodiments shown below, and can be implemented with arbitrary modifications without departing from the scope of the claims of the present invention and the equivalents thereof.
In the following description, "%" and "parts" representing quantities are by weight unless otherwise specified. Moreover, unless otherwise indicated, the operation described below was performed under conditions of normal temperature and normal pressure.

[Evaluation method]
(Measurement method of thickness)
The thickness of each layer contained in the film was measured as follows. The refractive index of each layer of the film to be a sample was measured using ellipsometry ("M-2000" manufactured by Woollam). Thereafter, using the measured refractive index, the thickness of the film was measured with a light interference type film thickness meter (“MCPD-9800” manufactured by Otsuka Electronics Co., Ltd.).

(Method of measuring weight average molecular weight and number average molecular weight)
The weight average molecular weight and the number average molecular weight of the polymer were measured as polystyrene equivalent values using a gel permeation chromatography (GPC) system (“HLC-8320” manufactured by Tosoh Corporation). At the time of measurement, an H-type column (manufactured by Tosoh Corporation) was used as a column, and tetrahydrofuran was used as a solvent. Moreover, the temperature at the time of measurement was 40.degree.

(Method of measuring the glass transition temperature Tg, melting point Tm and crystallization temperature Tpc of hydride of ring-opened polymer of dicyclopentadiene)
The sample heated to 300 ° C. in a nitrogen atmosphere is quenched with liquid nitrogen and heated at 10 ° C./min using a differential scanning calorimeter (DSC) to measure the glass transition temperature Tg, melting point Tm and crystallization temperature of the sample We asked for Tpc respectively.

(Method of measuring glass transition temperature of polyurethane)
The polyurethane aqueous dispersion used in the examples was poured into a Teflon (registered trademark) -treated container and dried at room temperature for 24 hours. Thereafter, it was further dried in an oven at 120 ° C. for 1 hour to prepare a 150 μm-thick layer of polyurethane. The glass transition temperature of this layered product was measured from the tan δ peak using a dynamic viscoelasticity measuring apparatus ("Rheogel-E4000" manufactured by UBM). At this time, when two peaks appeared, the lower temperature peak was adopted as the glass transition temperature.

(Measurement method of hydrogenation rate of polymer)
The hydrogenation rate of the polymer was measured by ¹ H-NMR measurement at 145 ° C. using ortho-dichlorobenzene-d ⁴ as a solvent.

(Method of measuring the ratio of racemo / dyad of polymer)
¹³ C-NMR measurement of the polymer by applying inverse-gated decoupling method at 200 ° C. using ortho-dichlorobenzene-d ⁴ / trichlorobenzene-d ³ (mixing ratio (mass basis) 1/2) as a solvent went. In the result of this ¹³ C-NMR measurement, using the peak at 127.5 ppm of ortho-dichlorobenzene-d ⁴ as a reference shift, the signal at 43.35 ppm from the meso dyad and the signal from 43.43 ppm from the racemo dyad Were identified. Based on the intensity ratio of these signals, the ratio of racemo dyad of the polymer was determined.

(Method of measuring crystallinity of polymer)
The degree of crystallization was confirmed by X-ray diffraction according to JIS K0131. Specifically, the diffracted X-ray intensity from the crystallized portion is determined using a wide-angle X-ray diffractometer ("RINT 2000" manufactured by Rigaku Corporation), and the ratio to the overall diffracted X-ray intensity is as follows: The degree of crystallinity was determined by (I).
Xc = K · Ic / It (I)
In the above formula (I), Xc represents the crystallinity of the test sample, Ic represents the diffracted X-ray intensity from the crystallized portion, It represents the entire diffracted X-ray intensity, and K represents the correction term.

(Method of measuring surface free energy)
The surface free energy of the surface of the film was measured by the following method.
Water and hexadecane were prepared as liquid samples. The contact angle to the surface of the film was measured for each of these liquid samples. The measurement method of the contact angle was as follows.
<Contact angle measurement method>
・ Measurement device: AutoDispenser AD-31 (made by Kyowa Interface Science Co., Ltd.)
Control analysis software: FAMAS ver 3.13
Contact angle measurement method: hanging drop method Analysis method: Young-Laplace method Teflon (R) coated needle: 18 G (or 22 G)
・ Liquid volume: 3 μL to 4 μL
・ Measurement waiting time: 3000 ms
・ Number of measurements: Measure 10 times and adopt the average value.

The measured contact angle θ was applied to the following Owens Wendt model to calculate the surface free energy r _S of the surface of the film. In the Owens Wendt model, the film corresponds to a solid sample. Further, in the Owens Wendt model, the meanings of symbols are as shown in Table 1 below, and the values of r _L , r _L ^d and r _L ^p of liquid samples are as shown in Table 2.

[Method for evaluating transferability of easy adhesion layer]
After peeling off the temporary support, the surface of the peeled temporary support was visually observed. As a result of observation, the transferability of the easily adhesive layer was determined according to the following criteria.
:: no attached piece consisting of a portion of the easily adhesive layer having a diameter of 50 μm or more remains on the surface of the temporary support at all.
Fair: One or more attached pieces consisting of a portion of the easy-adhesion layer having a diameter of 50 μm or more remain on the surface of the temporary support.
X: It was not possible to peel the temporary support from the easily bonding layer itself.

[Method for evaluating adhesion between easy adhesion layer and substrate film]
In the easily adhesive layer of the optical film, using a cutter, 11 cuts were vertically and horizontally inserted at intervals of 1 mm to make 100 squares (10 × 10) of 1 mm square (grid). A cellophane tape was attached to the surface of this easy-adhesion layer, which was quickly peeled off, and the number of squares remaining without peeling was counted. The larger the number of squares remaining without peeling, the better the adhesion between the easily bonding layer and the base film.

[Measurement of peel strength]
The surface of the easily adhesive layer of the optical film was subjected to corona treatment. In addition, one side of an unstretched film ("Zeonor film" manufactured by Nippon Zeon Co., Ltd., "Zeonor film", thickness 100 μm, glass transition temperature of resin 160 ° C) made of norbornene resin was subjected to corona treatment. An ultraviolet curable adhesive (“CRB 1352” manufactured by Toyo Ink Co., Ltd.) was applied to the corona-treated surface of the unstretched film. Then, the corona-treated surface of the optical film was attached to the surface coated with the adhesive using a laminator. Using a high pressure mercury lamp, the adhesive was crosslinked by irradiating ultraviolet light under the conditions of an illuminance of 350 mJ / cm ² and an integrated light amount of 1000 mJ / cm ² . Thereby, the bonding sample containing an optical film and an unstretched film was obtained. Then, the said bonding sample was cut | judged to the width | variety of 25 mm, the surface at the side of the optical film was bonded with the adhesive on the surface of slide glass, and the bonding thing was obtained. At the time of bonding, a double-sided pressure-sensitive adhesive tape (manufactured by Nitto Denko Corporation, product number “CS9621”) was used as a pressure-sensitive adhesive. After bonding, the bonded material was allowed to stand for 12 hours.
Thereafter, the end of the unstretched film was sandwiched by a jig at the tip of the force gauge, and pulled in the normal direction of the surface of the slide glass, whereby a 90-degree peel test was performed. The peeling speed at the time of pulling was 20 mm / min. Since the force measured when the unstretched film peels is the force required to peel the unstretched film from the optical film, the magnitude of this force was measured as the peel strength. This peel strength corresponds to the adhesive strength between the unstretched film and the optical film.

Production Example 1 Preparation of hydride of ring-opened polymer of dicyclopentadiene]
The metal pressure resistant reactor was thoroughly dried and then purged with nitrogen. In this metal pressure resistant reactor, 154.5 parts of cyclohexane, 42.8 parts of a 70% cyclohexane solution having a concentration of dicyclopentadiene (end body content of 99% or more) (30 parts as the amount of dicyclopentadiene), and 1- 1.9 parts of hexene were added and heated to 53 ° C.

To a solution of 0.014 part of tetrachlorotungsten phenylimide (tetrahydrofuran) complex dissolved in 0.70 part of toluene, 0.061 part of a 19% diethylaluminum ethoxide / n-hexane solution is added and stirred for 10 minutes. The catalyst solution was prepared.
The catalyst solution was added to a pressure resistant reactor to initiate a ring opening polymerization reaction. Then, the reaction was carried out for 4 hours while maintaining the temperature at 53 ° C. to obtain a solution of a ring-opened polymer of dicyclopentadiene.
The number average molecular weight (Mn) and weight average molecular weight (Mw) of the ring-opened polymer of dicyclopentadiene obtained are 8750 and 28,100, respectively, and the molecular weight distribution (Mw / Mn) determined therefrom is 3 It was .21.

To 200 parts of the obtained ring-opened polymer solution of dicyclopentadiene, 0.037 parts of 1,2-ethanediol as a terminator is added, and the mixture is heated to 60 ° C. and stirred for 1 hour to stop the polymerization reaction. I did. One part of a hydrotalcite-like compound ("Kyo Ward (registered trademark) 2000" manufactured by Kyowa Chemical Industry Co., Ltd.) was added thereto, and the mixture was heated to 60 ° C and stirred for 1 hour. Thereafter, 0.4 parts of a filter aid ("Radiot (registered trademark) # 1500" manufactured by Showa Kagaku Kogyo Co., Ltd.) is added, and a PP pleated cartridge filter ("TCP-HX" manufactured by ADVANTEC Toyo Corp.) The solution was filtered off.

100 parts of cyclohexane is added to 200 parts of a ring-opened polymer solution of dicyclopentadiene (30 parts of a polymer) after filtration, and 0.0043 parts of chlorohydridocarbonyltris (triphenylphosphine) ruthenium is added to obtain hydrogen. The hydrogenation reaction was performed at a pressure of 6 MPa and 180 ° C. for 4 hours. Thus, a reaction liquid containing a hydride of a ring-opened polymer of dicyclopentadiene was obtained. In this reaction liquid, hydride was precipitated to form a slurry solution.

The hydride and the solution contained in the above reaction solution are separated using a centrifugal separator, dried under reduced pressure at 60 ° C. for 24 hours, and hydride of the ring-opened polymer of dicyclopentadiene having crystallinity 28. I got 5 copies. The hydrogenation rate of this hydride was 99% or more, the glass transition temperature Tg was 94 ° C., the melting point (Tm) was 262 ° C., the crystallization temperature Tpc was 170 ° C., and the ratio of racemo dyad was 89%.

Production Example 2 Production of base film]
An antioxidant (tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl)] was added to 100 parts of the hydride of the ring-opened polymer of dicyclopentadiene obtained in Preparation Example 1. Propionate] Methane; 0.5 parts of “Irganox (registered trademark) 1010” manufactured by BASF Japan Ltd. was mixed to obtain a crystalline resin.

The crystalline resin was introduced into a twin-screw extruder ("TEM-37B" manufactured by Toshiba Machine Co., Ltd.) equipped with four die holes having an inner diameter of 3 mmΦ. The crystalline resin was formed into a strand-like molded product by hot melt extrusion using the above-mentioned twin-screw extruder. The molded body was shredded with a strand cutter to obtain a pellet of crystalline resin.

Subsequently, the obtained pellets were fed to a hot melt extruded film forming machine equipped with a T-die. Using this film forming machine, a long film (120 mm in width) made of the above-mentioned crystalline resin was produced by a method of winding it on a roll at a speed of 27 m / min. The operating conditions of the above-mentioned film forming machine are shown below.
Barrel temperature setting: 280 ° C to 290 ° C
・ Die temperature: 270 ° C
-Screw rotation speed: 30 rpm
・ Cast roll temperature: 70 ° C
Thus, a base film was obtained as a long crystalline resin film formed of the crystalline resin. The thickness of the obtained base film was 20 μm. The crystallinity of the hydride of the ring-opened polymer of dicyclopentadiene in this base film was 0.7%.

Production Example 3 Production of Coating Liquid for Easy Adhesion Layer]
100 parts by weight of an aqueous dispersion of carbonate-based polyurethane ("ADECABON TITLE SPX-0672" manufactured by ADEKA, glass transition temperature -16 ° C) and polyfunctional epoxy compound as a cross-linking agent (Nagase Chemtex Co., Ltd.) (Denacole EX-521), mixed with 2.7 parts of a surfactant, 0.18 parts of acetylene glycol as a surfactant (Surfinol 440, manufactured by Nisshin Chemical Industry Co., Ltd.), and ion-exchanged water as a solvent Thus, a coating liquid having a solid concentration of 30% was obtained.

Example 1
(1.1. Process of forming an easy adhesion layer on a temporary support)
As a temporary support, a resin film ("Zeonor film ZF16-050" manufactured by Nippon Zeon Co., Ltd .; thickness 50 μm; hereinafter, sometimes referred to as "temporary support 1") formed of a norbornene resin was prepared. The surface free energy of the surface of this temporary support 1 was measured. The coating liquid produced in Production Example 3 was applied to the surface of the temporary support 1. Thereafter, the layer of the applied coating liquid was dried at 90 ° C. for 120 seconds to form an easy-adhesion layer having a thickness of 100 nm on the surface of the temporary support 1.

(1.2. Corona treatment process to the film surface of a substrate film)
While the base film produced in Production Example 2 was conveyed in the longitudinal direction of the base film, the film surface was subjected to corona treatment. The corona treatment was performed under the conditions of an output of 100 W, an electrode width of 0.3 m, and a film transport speed of 0.080 m / min. The treatment intensity of the corona treatment under this condition is 4.2 kW · min / m ² . The surface free energy of the film surface of the substrate film subjected to corona treatment was measured.

(1.3. Bonding process)
The easily bonding layer formed on the surface of the temporary support 1 and the corona-treated surface of the base film were bonded.

(1.4. Peeling process of temporary support)
The temporary support 1 was peeled off to obtain a multilayer film provided with a base film and an easily adhesive layer. The surface of the peeled temporary support 1 was observed to evaluate the transferability of the easily adhesive layer.

(1.5. Stretching process)
The multilayer film was subjected to a stretching process of stretching in the width direction of the multilayer film under stretching conditions of a stretching temperature of 130 ° C., a stretching ratio of 1.2, and a stretching speed of 4 mm / min.

(1.6. Crystallization process)
After the stretching process, the multilayer film was subjected to a crystallization process of heating at a temperature of 170 ° C. for 30 seconds. The above-mentioned crystallization treatment was performed in a state in which the end of the multilayer film was fixed and strained, and no wrinkles were generated due to heat contraction.
Thereby, the optical film provided with a base film and an easily bonding layer was obtained. The degree of crystallization of the hydride of the ring-opened polymer of dicyclopentadiene in the substrate film contained in the obtained optical film was 73%. This optical film was evaluated by the method described above.

Example 2
The temporary support was changed to a resin film ("Zeonor film" manufactured by Nippon Zeon Co., Ltd., thickness 50 μm; hereinafter, sometimes referred to as "temporary support 2") formed of a norbornene resin.
The optical film was manufactured and evaluated in the same manner as in Example 1 except for the above matters.

[Example 3]
Resin film ("Zeonor film" manufactured by Nippon Zeon Co., Ltd., "Zeonor film" manufactured by Nippon Zeon Co., Ltd., thickness 100 μm, glass transition temperature of norbornene polymer 125 ° C; hereinafter referred to as "non-crystalline COP") There is a change.
Moreover, in the extending | stretching process of a multilayer film, the draw ratio was changed into 3.0 times.
Furthermore, the crystallization process was not performed with respect to a multilayer film, and the multilayer film obtained after the extending process was evaluated as an optical film.
The optical film was manufactured and evaluated in the same manner as in Example 1 except for the above matters.

Example 4
The temporary support was changed to a polyethylene terephthalate film (“Cosmo Shine (registered trademark) A4100” manufactured by Toyobo Co., Ltd., thickness 100 μm; hereinafter, sometimes referred to as “temporary support 3”).
The optical film was manufactured and evaluated in the same manner as in Example 1 except for the above matters.

[Comparative Example 1: Example in which an easily adhesive layer was not formed]
The substrate film produced in Production Example 2 was subjected to corona treatment, stretching treatment and crystallization treatment under the same conditions as in Example 1. That is, a substrate film was obtained instead of the optical film in the same manner as in Example 1 except that the substrate film and the easy adhesion layer were not laminated. The peel strength of the substrate film thus obtained was measured by the measurement method described above. In this measurement method, the corona-treated surface of the substrate film was bonded to the surface of a slide glass, and the peel strength was measured.

[Comparative example 2: an example in which the easy adhesion layer was not formed]
The substrate film prepared in Example 3 was subjected to corona treatment and stretching treatment under the same conditions as in Example 3. That is, a substrate film was obtained instead of the optical film in the same manner as in Example 3 except that the substrate film and the easy adhesion layer were not laminated. The peel strength of the substrate film thus obtained was measured by the measurement method described above. In this measurement method, the corona-treated surface of the substrate film was bonded to the surface of a slide glass, and the peel strength was measured.

[Comparative example 3: an example in which the heat treatment was not performed after bonding with the easy adhesion layer]
The base film produced in Production Example 2 was subjected to a stretching treatment and a crystallization treatment under the same conditions as in Example 1 to obtain a crystallized base film. This crystallized substrate film was used in place of the substrate film produced in Production Example 2.
Moreover, after performing bonding of this crystallization base film and an easily bonding layer, and peeling of a temporary support body, the extending | stretching process and the crystallization process were not performed.
The optical film was manufactured and evaluated in the same manner as in Example 1 except for the above matters.

[Comparative Example 4: Example in which the temperature of heat treatment was low]
The stretching temperature in the stretching process was changed to 90 ° C.
Moreover, the crystallization process was not performed.
The optical film was manufactured and evaluated in the same manner as in Example 1 except for the above matters.

[Comparative Example 5: Example in which the surface free energy of the temporary support surface was large]
Before applying the coating liquid produced in Production Example 3, the processing strength is 4.2 kW on the surface of the temporary support 1 under the conditions of 100 W output, 0.3 m electrode width, and 0.080 m / min film transport speed. -A corona treatment of min / m ² was applied.
The optical film was manufactured and evaluated in the same manner as in Example 1 except for the above matters. However, since the transferability of the easily adhesive layer was inferior, it was not possible to evaluate the adhesion between the easily adhesive layer and the base film and to measure the peel strength.

[Comparative Example 6: Example in which the surface free energy of the film surface of the base film was small]
The corona treatment to the film surface of the base film was not performed.
The optical film was manufactured and evaluated in the same manner as in Example 1 except for the above matters. However, since the transferability of the easily adhesive layer was inferior, it was not possible to evaluate the adhesion between the easily adhesive layer and the base film and to measure the peel strength.

[Comparative Example 7: Example in which the surface free energy of the film surface of the base film was small]
The treatment strength of the corona treatment to the film surface of the base film was changed to 3.2 kW · min / m ² .
The optical film was manufactured and evaluated in the same manner as in Example 1 except for the above matters. However, in Comparative Example 7, since the transferability of the easily adhesive layer was insufficient, evaluation of the peel strength was not performed.

[Comparative Example 8: Example in which the surface free energy of the temporary support surface was large]
The surface of a resin film ("Zeonor film ZF16-050" manufactured by Nippon Zeon Co., Ltd .; thickness 50 μm) formed of a norbornene resin was subjected to corona treatment at a treatment strength of 4.2 kW · min / m ² . The coating liquid produced in Production Example 3 was applied to the corona-treated surface. The layer of the applied coating liquid was dried at 90 ° C. for 120 seconds to form an easy-adhesion layer having a thickness of 100 nm. Thus, a temporary support (hereinafter sometimes referred to as "temporary support 5") having a multilayer structure provided with a resin film and an easily adhesive layer was obtained.

The temporary support 5 of this multilayer structure was used in place of the temporary support 1 used in Example 1. Under the present circumstances, the surface by the side of the easily bonding layer of temporary support body 5 of multilayer structure was used as a temporary supporting surface for forming an easily bonding layer.
Moreover, the corona treatment to the film surface of a base film was not performed.
The optical film was manufactured and evaluated in the same manner as in Example 1 except for the above matters. However, since the transferability of the easily adhesive layer was inferior, it was not possible to evaluate the adhesion between the easily adhesive layer and the base film and to measure the peel strength.

[result]
The results of the above-mentioned Examples and Comparative Examples are shown in Tables 3 and 4 below. In the following table, in the column of adhesion, the numerical value of the molecule represents the number of squares remaining without peeling of the easy adhesion layer.

[Consideration]
As can be seen from Comparative Example 3, the easy-adhesion layer formed on the temporary support surface of the temporary support is simply bonded to the base film formed of a resin containing an alicyclic structure-containing polymer, High adhesion can not be obtained and it peels easily. Moreover, even if it heat-processes, after sticking an easily bonding layer to a base film so that the comparative example 4 may show, high adhesiveness will be acquired if the temperature of the heat processing has remove | deviated from the predetermined temperature range. Absent. On the other hand, in the examples, after the easy adhesion layer is bonded to the base film, the adhesion between the easy adhesion layer and the base film is effectively improved by heat treatment in a predetermined temperature range. I was able to.
In addition, as can be seen from Comparative Examples 5 to 8, when the surface free energy of the temporary support surface of the temporary support and the surface free energy of the film surface of the base film are out of the predetermined range, they are formed on the temporary support surface. The easily adhesive layer can not be smoothly transferred to the film surface of the substrate film. On the other hand, in the examples, the surface free energy of the temporary support surface of the temporary support and the surface free energy of the film surface of the base film are within the predetermined range, so that the easy adhesion layer does not remain on the temporary support surface. Smooth transfer was realized.
From the above results, in the production method of the present invention, the film surface of the base film formed of a resin containing an alicyclic structure-containing polymer and the resin layer formed on a temporary support are bonded to form a group. It was confirmed that an optical film including a material film and a resin layer that is difficult to peel from the base film can be produced.

Furthermore, as can be seen from Comparative Examples 1 and 2, even if the base film formed of a resin containing an alicyclic structure-containing polymer is adhered to a member such as a slide glass using an adhesive or a pressure-sensitive adhesive, The adhesive strength is small. On the other hand, it is confirmed that the optical film can be strongly adhered to the above-mentioned member as shown in the examples by forming an easily adhesive layer as a resin layer on the substrate film to make it an optical film. It was done.

Claims

Forming a resin layer on the temporary support surface of the temporary support having a temporary support surface having a surface free energy of 20 mJ / m 2 or less,
A step of subjecting a film surface of a base film formed of a resin containing an alicyclic structure-containing polymer to a hydrophilic treatment such that the surface free energy of the film surface is 40 mJ / m 2 or more,
Bonding the resin layer formed on the temporary support surface of the temporary support and the film surface subjected to the hydrophilic treatment of the base film,
Peeling the temporary support, and
A method of producing an optical film, comprising the step of heat treating the resin layer and the base film at a temperature equal to or higher than the glass transition temperature of the alicyclic structure-containing polymer.
The manufacturing method of the optical film of Claim 1 in which the said alicyclic structure containing polymer has crystallinity.
The manufacturing method of the optical film of Claim 2 whose crystallinity degree of the said alicyclic structure containing polymer is less than 3%, before hydrophilic processing is given to the said film surface.
The manufacturing method of the optical film of Claim 2 or 3 in which crystallization of the said alicyclic structure containing polymer advances in the process of performing the said heat processing to the said resin layer and the said base film.
The step of applying the heat treatment to the resin layer and the base film
Stretching the substrate film;
5. A method for producing an optical film according to any one of claims 2 to 4, comprising the step of promoting crystallization of the alicyclic structure-containing polymer contained in the base film after stretching.
The method for producing an optical film according to any one of claims 1 to 5, wherein the hydrophilic treatment is at least one selected from the group consisting of corona treatment, plasma treatment and excimer treatment.
The optical film according to any one of claims 1 to 6, wherein the resin layer is formed of at least one selected from the group consisting of a urethane resin, an olefin resin, a polyester resin, an epoxy resin and an acrylic resin. Production method.