JP4868780B2 - Fluorine copolymer, polymerizable composition, curable resin composition, antireflection film, polarizing plate, and image display device - Google Patents

Description

  The present invention relates to a copolymer (fluorine copolymer) excellent in the formation of an antireflection film capable of forming a coating film excellent in low reflectance characteristics, and an optical material using the copolymer (particularly polymerization). Composition, curable resin composition, antireflection film, polarizing plate, image display device, and the like.

  In general, the antireflection film is used in a display device such as a cathode ray tube display (CRT), a plasma display (PDP), an electroluminescence display (ELD), or a liquid crystal display (LCD), and a contrast reduction or image due to reflection of external light. In order to prevent reflection of light, it is arranged on the outermost surface of the display in order to reduce reflectivity using the principle of optical interference.

  In general, such an antireflection film can be produced by forming a low refractive index layer having an appropriate thickness on the support and having a lower refractive index than that of the support. In order to realize a low reflectance, a material having a refractive index as low as possible is desired for the low refractive index layer. Further, since the antireflection film is used on the outermost surface of the display, high scratch resistance is required. For example, in order to realize high scratch resistance in a thin film having a thickness of around 100 nm, the strength of the coating itself and the adhesion to the lower layer are required.

  In order to lower the refractive index of a material, means of (1) introducing fluorine atoms and (2) lowering density (introducing voids) are known. There was a tendency that the scratch resistance was lowered and the low refractive index and the high scratch resistance were not compatible.

  As a method for increasing the film strength, there is a method using a fluorine-containing sol-gel film as described in Patent Documents 1 and 2, but in this method, (1) a long time is required for curing, and the manufacturing load is increased. There are large restrictions such as large, (2) lack of resistance to saponification liquid (alkali treatment liquid), and cannot be performed after film formation of the antireflection film when the plastic film surface is saponified.

On the other hand, Patent Documents 3 to 5 describe means for improving scratch resistance by introducing a polysiloxane structure into a fluorine-containing copolymer to lower the friction coefficient of the coating surface. Although this means is effective to some extent for improving scratch resistance, sufficient scratch resistance cannot be obtained for a film that lacks essential film strength and interfacial adhesion.
Patent Document 6 describes means for improving scratch resistance by improving the film strength and interfacial adhesion by using a fluorine-containing copolymer and inorganic fine particles in combination. However, it has been found that with this means, the inorganic fine particles are not sufficiently dispersed in the matrix of the fluorine-containing copolymer, and the inorganic fine particles are coarsely and densely generated in the film, resulting in an increase in haze. This problem is particularly problematic with a low reflection film having a smooth surface that does not have antiglare properties.

JP 2002-265866 A JP 2002-317152 A JP-A-11-189621 Japanese Patent Laid-Open No. 11-228631 JP 2000-313709 A International Publication WO-2004-017105A1

  An object of the present invention is to provide a copolymer excellent in formation of an antireflection film capable of forming a coating film excellent in low reflectance characteristics, and scratch resistance while maintaining sufficient antireflection properties. An object of the present invention is to provide an improved antireflection film. Furthermore, it is providing the polarizing plate and display apparatus using such an antireflection film.

（一般式（１）中、Ｒ¹およびＲ²は、それぞれ、アルキル基またはアリール基を表し、Ｒ¹およびＲ²の少なくとも１つはフッ素原子を含む。）
一般式（２）

（一般式（２）中、Ｒ³およびＲ⁴は、それぞれ、水素原子、アルキル基またはアリール基を表す。）
（２）下記一般式（１）で表される構造単位、下記一般式（２）で表される構造単位および下記一般式（３）で表される構造単位を含む共重合体。
一般式（1）

（一般式（１）中、Ｒ¹およびＲ²は、それぞれ、アルキル基またはアリール基を表し、Ｒ¹およびＲ²の少なくとも１つはフッ素原子を含む。）
一般式（２）

（一般式（２）中、Ｒ³およびＲ⁴は、それぞれ、水素原子、アルキル基またはアリール基を表す。）
一般式（３）

（一般式（３）中、Ｒ⁵は、アルキル基、アリール基、アルコキシ基またはアミノ基（アニリノ基を含む）を表し、Ｒ⁶はアルキル基を表す。）
（３）前記一般式（１）で表される構造単位を２０モル％以上、前記一般式（２）で表される構造単位を０．０５モル％以上、前記一般式（３）で表される構造単位を２０％モル以上含む（２）に記載の共重合体。
（４）前記一般式（１）中のＲ¹およびＲ²の少なくとも一方が、フッ素原子を含む炭素数２〜６のアルキル基、またはフッ素原子を含むアリール基である、（１）〜（３）のいずれか１項に記載の共重合体。
（５）前記一般式（３）中のＲ⁵およびＲ⁶が共にメチル基である、（２）〜（４）のいずれか１項に記載の共重合体。
（６）重量平均分子量が２，０００〜１，０００，０００である（１）〜（５）のいずれか１項に記載の共重合体。
（７）下記一般式（４）で表される化合物とポリシロキサン含有化合物とを含む重合性組成物。
一般式（４）

（一般式（４）中、Ｒ¹およびＲ²は、それぞれ、アルキル基またはアリール基を表し、Ｒ¹およびＲ²の少なくとも１つはフッ素原子を含む。）
（８）下記一般式（４）で表される化合物と、下記一般式（５）で表される化合物と、ポリシロキサン含有化合物とを含む重合性組成物。
一般式（４）

（一般式（４）中、Ｒ¹およびＲ²は、それぞれ、アルキル基またはアリール基を表し、Ｒ¹およびＲ²の少なくとも１つはフッ素原子を含む。）
一般式（５）

（一般式（５）中、Ｒ⁵は、アルキル基、アリール基、アルコキシ基またはアミノ基（アニリノ基を含む）を表し、Ｒ⁶はアルキル基を表す。）
（９）前記一般式（４）中のＲ¹およびＲ²の少なくとも一方が、フッ素原子を含む炭素数２〜６のアルキル基、またはフッ素原子を含むアリール基である、（７）または（８）に記載の重合性組成物。
（１０）前記一般式（５）のＲ⁵およびＲ⁶が共にメチル基である、（８）または（９）に記載の重合性組成物。
（１１）（１）〜（６）のいずれか１項に記載の共重合体、および溶剤を含有する、硬化性樹脂組成物。
（１２）（１１）に記載の硬化性樹脂組成物を用いてなる硬化膜。
（１３）（１１）に記載の硬化性樹脂組成物を用いてなる硬化膜からなる低屈折率層を有する、反射防止フィルム。
（１４）偏光子と該偏光子の少なくとも片側に設けられた保護フィルムとを有し、前記保護フィルムが（１３）に記載の反射防止フィルムである、偏光板。
（１５）（１３）に記載の反射防止フィルムを有する画像表示装置。 As a result of intensive studies, the present inventor has found that a copolymer having a specific structure achieves both low reflectance characteristics and improved coating strength, thereby solving the problem. Means for solving the above-mentioned problems are as follows.
(1) A copolymer comprising a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2).
General formula (1)

(In general formula (1), R ¹ and R ² each represents an alkyl group or an aryl group, and at least one of R ¹ and R ² contains a fluorine atom.)
General formula (2)

(In general formula (2), R ³ and R ⁴ each represent a hydrogen atom, an alkyl group or an aryl group.)
(2) A copolymer comprising a structural unit represented by the following general formula (1), a structural unit represented by the following general formula (2), and a structural unit represented by the following general formula (3).
General formula (1)

(In general formula (1), R ¹ and R ² each represents an alkyl group or an aryl group, and at least one of R ¹ and R ² contains a fluorine atom.)
General formula (2)

(In general formula (2), R ³ and R ⁴ each represent a hydrogen atom, an alkyl group or an aryl group.)
General formula (3)

(In general formula (3), R ⁵ represents an alkyl group, an aryl group, an alkoxy group or an amino group (including an anilino group), and R ⁶ represents an alkyl group.)
(3) The structural unit represented by the general formula (1) is 20 mol% or more, the structural unit represented by the general formula (2) is 0.05 mol% or more, and represented by the general formula (3). The copolymer as described in (2) containing 20% mol or more of structural units.
(4) (1) to (3), wherein at least one of R ¹ and R ^{2 in} the general formula (1) is a C 2-6 alkyl group containing a fluorine atom or an aryl group containing a fluorine atom. The copolymer according to any one of (1).
(5) The copolymer according to any one of (2) to (4), wherein R ⁵ and R ⁶ in the general formula (3) are both methyl groups.
(6) The copolymer according to any one of (1) to (5), wherein the weight average molecular weight is 2,000 to 1,000,000.
(7) A polymerizable composition comprising a compound represented by the following general formula (4) and a polysiloxane-containing compound.
General formula (4)

(In general formula (4), R ¹ and R ² each represents an alkyl group or an aryl group, and at least one of R ¹ and R ² contains a fluorine atom.)
(8) A polymerizable composition comprising a compound represented by the following general formula (4), a compound represented by the following general formula (5), and a polysiloxane-containing compound.
General formula (4)

(In general formula (4), R ¹ and R ² each represents an alkyl group or an aryl group, and at least one of R ¹ and R ² contains a fluorine atom.)
General formula (5)

(In general formula (5), R ⁵ represents an alkyl group, an aryl group, an alkoxy group or an amino group (including an anilino group), and R ⁶ represents an alkyl group.)
(9) (7) or (8), wherein at least one of R ¹ and R ^{2 in} the general formula (4) is a C 2-6 alkyl group containing a fluorine atom, or an aryl group containing a fluorine atom. The polymerizable composition as described in 1.).
(10) The polymerizable composition according to (8) or (9), wherein R ⁵ and R ^{6 in} the general formula (5) are both methyl groups.
(11) A curable resin composition comprising the copolymer according to any one of (1) to (6) and a solvent.
(12) A cured film using the curable resin composition according to (11).
(13) An antireflection film having a low refractive index layer made of a cured film using the curable resin composition according to (11).
(14) A polarizing plate comprising a polarizer and a protective film provided on at least one side of the polarizer, wherein the protective film is the antireflection film according to (13).
(15) An image display device having the antireflection film according to (13).

  The copolymer of the present invention and the curable resin composition containing the copolymer form a good cured film excellent in low reflectance characteristics, and the cured film has a low refractive index and excellent scratch resistance. Therefore, the copolymer of the present invention and the curable resin composition containing the copolymer can be advantageously used particularly for the formation of optical materials such as an antireflection film and an optical fiber clad material, and have a fluorine content. Taking advantage of this, it can be suitably used as a coating material, a weathering film material, a coating material, etc. for a substrate requiring weather resistance. Moreover, the cured film is particularly useful as an antireflection film because it has a low refractive index and excellent scratch resistance, and also has excellent adhesion to a substrate and imparts a good antireflection effect. By applying it to a display device, the visibility can be improved.

  Hereinafter, the contents of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

A: Copolymer The copolymer used in the present invention is a copolymer containing at least a repeating unit represented by the following general formula (1) and a repeating unit represented by the following general formula (2).

（一般式（１）中、Ｒ¹およびＲ²は、それぞれ、アルキル基またはアリール基を表し、Ｒ¹およびＲ²の少なくとも１つはフッ素原子を含む。） General formula (1)

(In general formula (1), R ¹ and R ² each represents an alkyl group or an aryl group, and at least one of R ¹ and R ² contains a fluorine atom.)

In the general formula (1), when R ¹ and R ² are alkyl groups, the alkyl groups may be linear, branched or cyclic. In addition, the alkyl group preferably has 1 to 10 carbon atoms, and more preferably 1 to 6 carbon atoms. Specific examples include a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a benzyl group, a cyclohexyl group, and the like.
In general formula (1), when R ¹ and R ² are aryl groups, it is preferably 6 to 8 carbon atoms. Specific examples include a phenyl group and a p-tolyl group.
Furthermore, at least one of R ¹ and R ² contains one or more fluorine atoms. R ¹ and / or R ² containing a fluorine atom is a C 2-6 alkyl group containing a fluorine atom (for example, 2,2,2-trifluoroethyl group, 2,2,3,3, -tetra Fluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, 2,2,3,3,4,4,5,5-octafluoropentyl group, 1-trifluoromethyl-2,2, 2-trifluoroethyl group (hexafluoroisopropyl group) and the like) or an aryl group containing a fluorine atom (for example, a pentafluorophenyl group) is preferable.

（一般式（２）中、Ｒ³およびＲ⁴は、それぞれ、水素原子、アルキル基またはアリール基を表す。） General formula (2)

(In general formula (2), R ³ and R ⁴ each represent a hydrogen atom, an alkyl group or an aryl group.)

In the general formula (2), when R ³ and R ⁴ are alkyl groups, the alkyl groups may be linear, branched or cyclic. In addition, the alkyl group preferably has 1 to 10 carbon atoms, and more preferably 1 to 6 carbon atoms. Specific examples include a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a benzyl group, a cyclohexyl group, and the like, and a methyl group is particularly preferable. As will be described later, R ³ and R ⁴ may be substituted with a substituent, but the substituent that the alkyl group has is particularly preferably a halogen atom.
In General Formula (2), when R ³ and R ⁴ are aryl groups, it is preferably 6 to 8 carbon atoms. Specific examples include a phenyl group and a p-tolyl group.

（一般式（３）中、Ｒ⁵は、アルキル基、アリール基、アルコキシ基またはアミノ基（アニリノ基を含む）を表し、Ｒ⁶はアルキル基を表す。） The copolymer of the present invention contains a structural unit represented by the following general formula (3) in addition to the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2). Is preferred.
General formula (3)

(In general formula (3), R ⁵ represents an alkyl group, an aryl group, an alkoxy group or an amino group (including an anilino group), and R ⁶ represents an alkyl group.)

When R ⁵ in the general formula (3) is an alkyl group, it may be linear, branched or cyclic, and is preferably linear or branched. It is preferable that carbon number of an alkyl group is 1-6. Preferred alkyl groups include a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a cyclohexyl group, a trifluoromethyl group, and a pentafluoroethyl group.
When R ⁵ in the general formula (3) is an aryl group, it preferably has 6 to 9 carbon atoms, and preferred examples include a phenyl group, a pentafluorophenyl group, a p-tolyl group, and a p-chlorophenyl group. Be
When R < ⁵ > in General formula (3) is an alkoxy group, it is preferable that it is C1-C7, and a methoxy group, an ethoxy group, a phenyloxy group etc. are mentioned specifically ,.
When R < ⁵ > in General formula (3) is an amino group, it is preferable that it is C1-C7, and a N, N- dimethylamino group, a piperidino group, an anilino group etc. are mentioned specifically ,.
R ⁵ is preferably an alkyl group having 1 to 6 carbon atoms, particularly preferably a methyl group or a trifluoromethyl group, and most preferably a methyl group.

The alkyl group as R ⁶ may be linear, branched or cyclic, and is preferably linear or branched. Further, as described later, it may have a substituent, but it is particularly preferable to have a halogen atom (more preferably, a fluorine atom) as a substituent. It is preferable that carbon number of an alkyl group is 1-6. Specific examples include a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a cyclohexyl group, a trifluoromethyl group, and a pentafluoroethyl group, and a methyl group is particularly preferable.
In particular, it is preferable that R ⁵ and R ⁶ in the general formula (3) are both alkyl groups having 1 to 6 carbon atoms, and it is most preferable that both are methyl groups.

R ^{1 to} R ⁶ may be further substituted with a substitutable group. Substituents at that time include halogen atoms (preferably fluorine atoms), alkyl groups, aryl groups, heterocyclic groups, cyano groups, hydroxyl groups, nitro groups, carboxyl groups, alkoxy groups, aryloxy groups, silyloxy groups. , Heterocyclic oxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy, amino group (including anilino group), acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group Sulfamoylamino group, alkylsulfonylamino group, arylsulfonylamino group, mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, sulfo group, alkylsulfinyl group, arylsulfur group Nyl group, alkylsulfonyl group, arylsulfonyl group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, carbamoyl group, arylazo group, heterocyclic azo group, imide group, phosphino group, phosphinyl group, phosphinyloxy group, phosphine group Examples include a finylamino group and a silyl group.

（一般式（４）中、Ｒ¹およびＲ²は、それぞれ、アルキル基またはアリール基を表し、Ｒ¹およびＲ²の少なくとも１つはフッ素原子を含む。）
一般式（４）中のＲ¹およびＲ²は、それぞれ、一般式（１）におけるＲ¹またはＲ²と同義であり、好ましい範囲も同義である。
この不飽和化合物にはトランス体（フマル酸ジエステル）と、シス体（マレイン酸ジエステル）があるが、どちららでもよく、好ましくはトランス体である。 Next, the monomer used as the raw material of the copolymer of this invention is demonstrated.
The polymer of the present invention can be synthesized from, for example, a polymerizable composition containing a compound represented by the following general formula (4) and a siloxane unit source. Two or more compounds represented by the general formula (4) may be used.
General formula (4)

(In general formula (4), R ¹ and R ² each represents an alkyl group or an aryl group, and at least one of R ¹ and R ² contains a fluorine atom.)
R ¹ and R ² in the general formula (4) each have the same meaning as R ¹ or R ² in the general formula (1), and the preferred range is also the same.
The unsaturated compound includes a trans isomer (fumaric acid diester) and a cis isomer (maleic acid diester). Either of them may be used, and a trans isomer is preferable.

When R ¹ and R ² are the same as shown in the following reaction formula A (R ¹ = R ² = R), the compound represented by the general formula (4) is obtained from commercially available fumaroyl chloride and alcohol. It can be synthesized in a single step. When R ¹ and R ² are different, for example, it can be obtained by sequentially reacting with two corresponding alcohols using maleic anhydride as a starting material using the method described in JP-A-8-160365. it can.
Reaction formula A

  Specific examples of the compound represented by the general formula (4) used in the present invention are listed below, but the present invention is not limited to these specific examples.

  The copolymer of the present invention is more preferably synthesized from a polymerizable composition containing a compound represented by the following general formula (5) in addition to the compound represented by the general formula (4) and the siloxane unit source. Two or more compounds represented by the general formula (5) may be used.

（一般式（５）中、Ｒ⁵は、アルキル基、アリール基、アルコキシ基またはアミノ基（アニリノ基を含む）を表し、Ｒ⁶はアルキル基を表す。）
一般式（５）中、Ｒ⁵およびＲ⁶は、それぞれ、一般式（３）におけるＲ⁵またはＲ⁶と同義であり、好ましい範囲も同義である。 General formula (5)

(In general formula (5), R ⁵ represents an alkyl group, an aryl group, an alkoxy group or an amino group (including an anilino group), and R ⁶ represents an alkyl group.)
In general formula (5), R ⁵ and R ⁶ have the same meaning as R ⁵ or R ⁶ in general formula (3), respectively, and the preferred range is also the same.

  Specific examples of the compound represented by the general formula (5) used in the present invention are listed below, but the present invention is not limited to these specific examples.

The introduction site and introduction method of the structural unit (siloxane unit) represented by the general formula (2) contained in the copolymer of the present invention are not particularly limited, but the following three are typical and preferred methods.
(1) A method for introducing a fumarate having a siloxane unit into a side chain as one of monomers, (2) a method for introducing a vinyl monomer having a siloxane unit into a side chain, and (3) using an initiator having a siloxane unit. How to introduce into the main chain

(1) Method of introducing a fumarate having a siloxane unit into a side chain as one of monomers It is preferable to use a compound (fumaric acid ester or maleic acid ester) represented by the following general formula (6) as one of raw materials. .

（一般式（６）中、Ｒ⁷およびＲ⁸のうち少なくとも一方は、下記ＳＵ−１

（上記式中、Ｒ⁹〜Ｒ¹³は、それぞれ、水素原子、アルキル基、アリール基を表し、Ｌ¹は炭素数１〜２０の連結基を表し、ｎは０または１の整数を表し、ｐは１０〜１０００の整数を表す。）
で表される置換基である。Ｒ⁷およびＲ⁸のうち一方のみがＳＵ−１である場合、他方はアルキル基またはアリール基を表す。） General formula (6)

(In General Formula (6), at least one of R ⁷ and R ⁸ is the following SU-1

(In the above formulas, R ^{9 to} R ¹³ each represent a hydrogen atom, an alkyl group, or an aryl group, L ¹ represents a linking group having 1 to 20 carbon atoms, n represents an integer of 0 or 1, p Represents an integer of 10 to 1000.)
It is a substituent represented by these. When only one of R ⁷ and R ⁸ is SU-1, the other represents an alkyl group or an aryl group. )

When R ⁷ and R ⁸ are alkyl groups, the alkyl groups may be linear, branched, or cyclic. The alkyl group preferably has 10 or less carbon atoms, more preferably 5 or less carbon atoms. Specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, tert-butyl group, trifluoromethyl group, 2-trifluoroethyl group, 1H, 1H, 3H-tetrafluoropropyl Examples include groups.
When R ⁷ and R ⁸ are an aryl group, the aryl group preferably has 6 to 8 carbon atoms, and preferred examples include a phenyl group, a methylphenyl group, a pentafluorophenyl group, and a p-methoxyphenyl group. be able to.

When R ^{9 to} R ¹³ are alkyl groups, the alkyl groups may be linear, branched, or cyclic. The alkyl group preferably has 10 or less carbon atoms, more preferably 5 or less carbon atoms. Specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, tert-butyl group, trifluoromethyl group, 2-trifluoroethyl group, 1H, 1H, 3H-tetrafluoropropyl Examples include groups.
When R ^{9 to} R ¹³ are an aryl group, the aryl group preferably has 6 to 8 carbon atoms, and examples thereof include a phenyl group, a methylphenyl group, a pentafluorophenyl group, and a p-methoxyphenyl group. .
As R < ⁹ > -R < ¹³ >, an alkyl group is preferable and a methyl group is particularly preferable.
L ¹ is preferably an alkylene group having 5 or less carbon atoms.
p is preferably an integer of 30 to 500.

R ^{7 to} R ¹³ may have a substituent, and examples of the substituent include a halogen atom (preferably a fluorine atom) and the substituents exemplified as the substituents of R ^{1 to} R ⁶ above. As mentioned.

Specific examples of the compound represented by the general formula (6) are given below, but the present invention is not limited to these specific examples.

(2) Method of introducing a vinyl monomer having a siloxane unit into a side chain An arbitrary siloxane-containing vinyl monomer copolymerizable with the compound represented by the general formula (4) and the compound represented by the general formula (5) For example, a compound represented by the following general formula (7), a compound represented by the following general formula (8), and a compound represented by the general formula (9) It is preferable to use at least one compound.

In general formulas (7) to (9), R ¹⁴ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and preferably a hydrogen atom or a methyl group.
Moreover, about the definition and preferable example of R < ⁹ > -R < ¹³ >, L < ¹ >, p, n in SU-1, it is synonymous with the definition described in the said General formula (6), and its preferable range is also synonymous.

 Specific examples of the compounds represented by the general formulas (7) to (9) are given below, but the present invention is not limited to these specific examples.

(3) Method of introducing into the main chain using an initiator having a siloxane unit By using an initiator having a siloxane unit in the molecule, it is possible to introduce a siloxane unit into the main chain. Although the kind of initiator which has a siloxane unit is not specifically limited, As an example, the siloxane unit containing azo initiator which has a structural unit represented by following General formula (10) is mentioned.

（一般式（１０）中、Ｒ¹⁵〜Ｒ¹⁸は、それぞれ、アルキル基またはアリール基を表し、Ｘは１０〜１０００の整数を表す。） General formula (10)

(In the general formula (10), R ^{15 to} R ¹⁸ each represents an alkyl group or an aryl group, and X represents an integer of 10 to 1000.)

When R ^{15 to} R ¹⁸ in the general formula (10) are alkyl groups, the alkyl group may be linear, branched or cyclic, and is preferably linear or branched. The alkyl group preferably has 10 or less carbon atoms, more preferably 5 or less carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a trifluoromethyl group, a 2-trifluoroethyl group, and a 1H, 1H-pentafluoropropyl group. Can be mentioned.
When R ^{15 to} R ¹⁸ in the general formula (10) are an aryl group, the aryl group preferably has 6 to 8 carbon atoms, and includes a phenyl group, a methylphenyl group, a pentafluorophenyl group, and a p-methoxyphenyl group. And so on.
X is preferably an integer of 30 to 500.

  Specific examples of the siloxane unit-containing azo initiator represented by the general formula (10) are given below, but the present invention is not limited to these specific examples.

Among these, “VPS1001” (10-1) or “VPS0501” (10-2), which are polysiloxane-containing azo initiators manufactured by Wako Pure Chemical Industries, Ltd., are particularly preferable examples.
Moreover, when superposing | polymerizing using these siloxane unit containing azo initiators, you may use together another general radical polymerization initiator.

  In addition to the raw material monomer of the copolymer of the present invention (for example, a compound represented by the general formula (4), a compound represented by the general formula (5), a compound represented by the general formula (6), etc.) Any vinyl monomer (monomer C) that can be copolymerized with the raw material monomer may be used. The monomer C can also have functions such as imparting adhesion and solvent solubility, a crosslinkable group or a substituent for linking the crosslinkable group.

  Specific examples of the monomer C capable of radical copolymerization are shown below, but the compounds that can be used in the present invention are not limited to these specific examples.

The copolymer of the present invention preferably contains 20 mol% or more of the structural unit represented by the general formula (1) and 0.05 to 20 mol% of the structural unit represented by the general formula (2).
Furthermore, when the structural unit represented by the general formula (3) is included, the structural unit represented by the general formula (1) is 20 mol% or more, and the structural unit represented by the general formula (2) is 0.05 to It is preferable to contain 20% by mole or more and 20% by mole of the structural unit represented by the general formula (3). In the copolymer of the present invention, the total of these structural units may be 100 mol%, but may contain other structural units.
By making the structural unit represented by the general formula (2) 20 mol% or less, it is possible to more effectively suppress the phase separation and lowering of the transparency of the resin, and 0.05 mol% or more. Therefore, when it is set as an antireflection film, more sufficient scratch resistance and antifouling properties can be obtained.
Moreover, it is more preferable that 30 mol% or more of the structural unit represented by the general formula (1) is included.
Furthermore, it is more preferable to contain 0.5-15 mol% of structural units represented by the general formula (2).
In addition, it is more preferable to contain 30 mol% or more of the structural unit represented by the general formula (3).

  The copolymer of the present invention includes at least a structural unit represented by the general formula (1) and a structural unit represented by the general formula (2), and each of these includes only one type. Alternatively, two or more types may be included. Further, when the structural unit represented by the general formula (3) is also included, only one type of repeating unit represented by the general formula (3) may be included, or two or more types may be included. Good.

The copolymer of the present invention is a transparent (ultraviolet to near infrared region), amorphous copolymer, and is soluble in common solvents (particularly tetrahydrofuran (THF), ethyl acetate, acetone). The molecular weight of the copolymer of the present invention is preferably a number average molecular weight of 1,000 to 1,000,000 (number average molecular weight in terms of styrene measured by gel permeation chromatography), more preferably. Is 2,000 to 900,000, more preferably 5,000 to 500,000. On the other hand, the weight average molecular weight is preferably 2,000 to 1,000,000, and more preferably 10,000 to 600,000.
Further, the refractive index of the copolymer of the present invention is preferably 1.50 or less, more preferably 1.45 or less.
Furthermore, the glass transition temperature (Tg) of the copolymer of the present invention is preferably 60 ° C. or higher, and more preferably 80 to 160 ° C.

  Although the example of the copolymer which can be used by this invention is given to the following, it is not limited to these specific examples. Further, the chains may be linked by a crosslinking agent or a crosslinking monomer. The ratio of each structural unit can be arbitrarily selected, and the preferable ratio is as described above. Further, (SU-0501) and (SU-1001) represent siloxane units derived from the aforementioned initiators VPS-0501 and VPS-1001, respectively.

  As a method for producing the copolymer, a known polymerization method can be used. For example, bulk polymerization, solution polymerization, emulsion polymerization in water or emulsion, suspension polymerization method and the like. The polymerization method can be appropriately selected depending on the application and required performance of the present invention.

  The polymerization conditions of the copolymer of the present invention are not particularly limited, and are appropriately selected according to the monomer used and the molecular weight of the target copolymer.

As a polymerization initiator, it can select suitably according to the monomer and polymerization method to be used, but benzoyl peroxide (BPO), tert-butylperoxy-2-ethylhexanate (PBO), di-tert-butylperoxide. Peroxide compounds such as oxide (PBD), tert-butyl peroxyisopropyl carbonate (PBI), n-butyl 4,4, bis (tert-butylperoxy) valerate (PHV), or 2,2′-azobis Isobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2-methylpropane), 2, 2'-azobis (2-methylbutane), 2,2'-azobis (2-methylpentane), 2,2'-azobis (2, 3-dimethylbutane), 2,2′-azobis (2-methylhexane), 2,2′-azobis (2,4-dimethylpentane), 2,2′-azobis (2,3,3-trimethylbutane) 2,2′-azobis (2,4,4-trimethylpentane), 3,3′-azobis (3-methylpentane), 3,3′-azobis (3-methylhexane), 3,3′-azobis (3,4-dimethylpentane), 3,3′-azobis (3-ethylpentane), dimethyl-2,2′-azobis (2-methylpropionate), diethyl-2,2′-azobis (2- Examples thereof include azo compounds such as methyl propionate), di-tert-butyl-2,2′-azobis (2-methylpropionate), and 4,4-azobis (4-cyanopentanoic acid). Two or more kinds of polymerization initiators may be used in combination.
In the case of processes carried out in an aqueous medium, further inorganic free radical generators such as persulfates or “redox” compounds can be used.

  Moreover, you may use a chain transfer agent suitably for molecular weight adjustment. The chain transfer agent is mainly used for adjusting the molecular weight of the polymer. About the said chain transfer agent, according to the kind of polymeric monomer, a kind and addition amount can be selected suitably. For the chain transfer constant of the chain transfer agent for each monomer, reference can be made, for example, to the copolymer handbook 3rd edition (edited by J. BRANDRUP and EH IMMERGUT, published by JOHN WILEY & SON). The chain transfer constant can also be obtained by experiment with reference to Takayuki Otsu and Masaaki Kinoshita "Experimental Method for Polymer Synthesis", Kagaku Dojin, published in 1972.

  Examples of chain transfer agents include alkyl mercaptans (n-butyl mercaptan, n-pentyl mercaptan, n-octyl mercaptan, n-lauryl mercaptan, tert-dodecyl mercaptan, etc.), thiophenols (thiophenol, m-bromothiophenol, p-bromothiophenol, m-toluenethiol, p-toluenethiol, etc.) are preferably used, and among them, alkyl mercaptans such as n-octyl mercaptan, n-lauryl mercaptan, and tert-dodecyl mercaptan are preferably used. A chain transfer agent in which a hydrogen atom of a C—H bond is substituted with a deuterium atom or a fluorine atom can also be used. Two or more chain transfer agents may be used in combination.

  In general, the polymerization temperature depends on the decomposition rate of the selected polymerization initiator system, and is preferably 0-200 ° C, more preferably 40-120 ° C.

  The polymerization reaction for obtaining the copolymer of the present invention is preferably one in which the reaction solution obtained by the polymerization reaction can be used as it is as the curable resin composition, and is preferably performed in a solution polymerization system using an organic solvent. . Examples of preferable polymerization solvents include (1) esters such as ethyl acetate, butyl acetate, isopropyl acetate, isobutyl acetate, and cellosolve; (2) ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; (3) Cyclic ethers such as tetrahydrofuran and dioxane; (4) Amides such as N, N-dimethylformamide and N, N-dimethylacetamide; (5) Aromatic hydrocarbons such as toluene and xylene; be able to. Among these, esters, ketones and ethers are preferable. Particularly preferred are ethyl acetate, acetone, and methyl ethyl ketone, which have a very low boiling point and do not impose a burden on drying. Further, if necessary, alcohols, aliphatic hydrocarbons and the like can be mixed and used.

  The copolymer of the present invention may be appropriately post-treated with respect to the reaction solution obtained by the polymerization reaction. As this post-treatment, a general reprecipitation treatment (for example, a purification method in which a polymerization reaction solution is added dropwise to an insolubilizing solvent of a copolymer made of alcohol or the like to insolubilize the copolymer) is performed. Then, a solution of a specific copolymer can be prepared by dissolving the obtained solid copolymer in a solvent. Moreover, what removed the residual monomer from the polymerization reaction solution can also be used as a solution of a specific copolymer as it is.

B: Curable resin composition containing a copolymer The curable resin composition of the present invention preferably actually has curability, and when the copolymer itself does not have sufficient curability, Furthermore, by adding various crosslinkable compounds, additives, polymerization initiators, etc., and taking a three-dimensional crosslink structure or IPN (Inter Penetrating Network) structure, the necessary curability is imparted and the curing characteristics are improved. Also good. When a crosslinkable compound is used, a mixture of the crosslinkable compound and a copolymer is used as the curable resin composition, or a reaction product obtained by reacting all of the specific copolymer and the crosslinkable compound. A product obtained by reacting a product or a part thereof can also be used as the curable resin composition.

  The curable resin composition used in the present invention preferably takes the form of a liquid, and includes the copolymer of the present invention and a solvent for dissolving the copolymer as essential constituents, and various crosslinking agents, additives and It is prepared by dissolving a polymerization initiator. At this time, the concentration of the solid content is appropriately selected according to the use, but is preferably 0.01 to 60% by mass, more preferably 0.5 to 50% by mass, and further preferably 1 to 20% by mass. %.

  The solvent contained in the curable resin composition is not particularly limited as long as the composition containing the copolymer of the present invention can be uniformly dissolved or dispersed without causing precipitation. May be used in combination. Preferred solvents include ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), esters (ethyl acetate, butyl acetate, etc.), ethers (tetrahydrofuran, 1,4-dioxane, etc.), alcohols (methanol, ethanol, isopropyl). Alcohol, butanol, ethylene glycol, etc.) and aromatic hydrocarbons (toluene, xylene, etc.). As described above, since it is preferable that the reaction solution obtained by the polymerization reaction can be used as it is as the curable resin composition, it is preferable that the polymerization solvent also serves as the solvent contained in the curable resin composition. Furthermore, it is more preferable to use the reaction solution obtained by the polymerization reaction after further diluting an appropriate amount with the same type of solvent as the polymerization solvent.

  In addition, additives such as fine particles such as silica, various silane coupling agents or hydrolyzed partial condensates thereof, surfactants, thickeners, leveling agents, etc. may be added as necessary to the curable resin composition. Also good.

Examples of the curing mode of the copolymer contained in the curable resin composition of the present invention include the following three methods.
The first is to add a functional group such as a hydroxyl group or amino group to the side chain of the copolymer and react with a polyfunctional crosslinking agent such as a polyfunctional isocyanate to form a three-dimensional crosslinked structure. Provides a side chain of the copolymer with a polymerizable group such as a (meth) acryloyl group and reacts with a polymerization initiator to form a three-dimensional crosslinked structure, and the third is a monofunctional or polyfunctional polymerization. A compound having a functional group is added to the copolymer and polymerized in a mixed state, and there is no direct bond between them, but the curing characteristics are improved in a manner that causes entanglement between the polymers.
These curing modes will be specifically described below.

(1) The first is a curable resin composition comprising a combination of a polyfunctional crosslinking agent and a copolymer having a functional group that reacts therewith, but when the copolymer of the present invention has a hydroxyl group in the side chain, It hardens | cures by making the hydroxyl group of a side chain and a (polyfunctional) crosslinking agent react. As a method of introducing a hydroxyl group into the copolymer of the present invention, as described above, a method of introducing a hydroxyl group or a copolymer protected with a hydroxyl group into one side chain as one of the copolymer components, and deprotecting as necessary. Is preferred.
On the other hand, the (polyfunctional) crosslinking agent used may be a low molecule, an oligomer, or a polymer. Depending on the type of (polyfunctional) crosslinking agent to be used, it can be divided into (I) curing using an amino resin, (II) curing using a polyfunctional isocyanate, and (III) curing using a cationic polymerizable crosslinking agent. In the case of curing with the amino resin (I), examples of the amino resin to be used include urea resin, melamine resin, benzoguanamine resin, acetoguanamine resin, and the like, and melamine resin is particularly preferable from the viewpoint of the performance and cost of the cured film. In the case of curing using the polyfunctional isocyanate of (II), examples of the polyfunctional isocyanate compound used include triphenylmethane triisocyanate, toluylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate and the like. However, toluylene diisocyanate is particularly preferable from the viewpoint of reactivity. (III) When curing with a cationically polymerizable crosslinking agent, the crosslinking agent used preferably has a ring-opening polymerizable group such as an epoxy group, an oxetanyl group, or an oxazolyl group as the cationically polymerizable group, particularly those having an epoxy group. preferable. These crosslinking methods (I), (II), and (III) may be used alone or in combination. The crosslinkable compounds used in (I), (II), and (III) are not limited to the compounds shown here. For example, the crosslinkers shown in the document “Crosslinker Handbook” (Taisei) May be used.

(2) The second is a mode in which a polymerizable group such as a (meth) acryloyl group is added to the side chain of the copolymer of the present invention and reacted with a polymerization initiator to form a three-dimensional crosslinked structure. When the polymer structure is a fluorine-containing copolymer in which a (meth) acryloyl group is introduced into the side chain, curing is performed by radical polymerization of the introduced (meth) acryloyl group. As a method for introducing the (meth) acryloyl group into the copolymer, the following methods (a) to (f) are preferable. That is, (a) after synthesizing a copolymer having a nucleophilic group such as a hydroxyl group and an amino group, (meth) acrylic acid chloride, (meth) acrylic anhydride, and a mixture of (meth) acrylic acid and methanesulfonic acid A method in which an acid anhydride is allowed to act, (b) a method in which (meth) acrylic acid is allowed to act on the copolymer having the nucleophilic group in the presence of a catalyst such as sulfuric acid, and (c) a copolymer having the nucleophilic group. (E) a method in which a compound having both an isocyanate group such as methacryloyloxypropyl isocyanate and a (meth) acryloyl group is allowed to act on the coalescence; (d) a method in which (meth) acrylic acid is allowed to act after synthesizing a copolymer having an epoxy group; ) A method of causing a compound having both an epoxy group such as glycidyl methacrylate and a (meth) acryloyl group to act on a copolymer having a carboxyl group, (f A method of performing dehydrochlorination after obtained by polymerizing a vinyl monomer having a 3-chloropropionic acid ester moiety. Among these, (a) or (b) is particularly preferable for a copolymer having a hydroxyl group.
As the radical polymerization initiator, any one that generates radicals by the action of heat (thermal polymerization initiator) or one that generates radicals by the action of light (photopolymerization initiator) can be used.

(3) The third is a mode in which a compound having a monofunctional / polyfunctional polymerizable group is added and polymerized in the copolymer, and there is no direct bond between them, but the polymers are entangled with each other. It is. The copolymer itself of the present invention itself does not require the introduction of a functional group as described in (1) or (2) above. A polymerizable compound having an ethylenically unsaturated group is added to the copolymer and cured by irradiation with active energy in the presence of a photopolymerization initiator or heating in the presence of a thermal polymerization initiator. As the polymerizable compound to be used, those having two or more, more preferably five or more ethylenically unsaturated groups in one molecule are used. Examples of monomers having two or more ethylenically unsaturated groups include esters of polyhydric alcohols and (meth) acrylic acid (for example, ethylene glycol di (meth) acrylate, 1,4-cyclohexanediacrylate, pentaerythritol). Tetra (meth) acrylate), pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate , Dipentaerythritol hexa (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester Terpolyacrylate), vinylbenzene and derivatives thereof (for example, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinylsulfone (for example, divinylsulfone), acrylamide (For example, methylenebisacrylamide) and methacrylamide. Two or more of these monomers may be used in combination.

  In the above (2) or (3), when a compound that initiates radical polymerization by the action of heat is used, the film is cured by heating. As such a thermal polymerization initiator, organic or inorganic peroxides, organic azo or diazo compounds can be used. Specifically, benzoyl peroxide (BPO), tert-butylperoxy-2-ethylhexanate (PBO), di-tert-butyl peroxide (PBD), tert-butylperoxyisopropyl carbonate as organic oxides (PBI), n-butyl 4,4, bis (tert-butylperoxy) valerate (PHV), 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methyl) as azo compounds Butyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2-methylpropane), 2,2′-azobis (2-methylbutane), 2,2′- Azobis (2-methylpentane), 2,2′-azobis (2,3-dimethylbutane), 2,2′-azobis (2-methylhexane), 2 2'-azobis (2,4-dimethylpentane), 2,2'-azobis (2,3,3-trimethylbutane), 2,2'-azobis (2,4,4-trimethylpentane), 3,3 '-Azobis (3-methylpentane), 3,3'-azobis (3-methylhexane), 3,3'-azobis (3,4-dimethylpentane), 3,3'-azobis (3-ethylpentane) , Dimethyl-2,2′-azobis (2-methylpropionate), diethyl-2,2′-azobis (2-methylpropionate), di-tert-butyl-2,2′-azobis (2-methyl) Propionate) and 4,4-azobis (4-cyanopentanoic acid). Two or more kinds of polymerization initiators may be used in combination.

  When hardening by heat, it is preferable to harden | cure at 30-200 degreeC, More preferably, it is 80-180 degreeC, Most preferably, it is 100-150 degreeC. The heating time is preferably 1 second to 100 hours, more preferably 5 seconds to 20 hours, and particularly preferably 10 seconds to 1 hour.

When using a compound that initiates radical polymerization by the action of light, the film is cured by irradiation with active energy rays. Examples of such photopolymerization initiators include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfides There are compounds, fluoroamine compounds, and aromatic sulfoniums. Examples of acetophenones include 2,2-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxydimethylphenyl ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-4-methylthio-2-morpholinopropiophenone, and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone. Examples of benzoins include benzoin benzene sulfonate, benzoin toluene sulfonate, benzoin methyl ether, benzoin ethyl ether, and benzoin propyl ether. Examples of benzophenones include benzophenone, 2,4-dichlorobenzopheno, 4,4-dichlorobenzophenone, and p-chlorobenzophenone. Examples of phosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide.
Various examples are also described in the latest UV curing technology (P-359, issuer: Kazuhiro Takasagi, publisher; Technical Information Association, Inc., published in 1991), which is useful for the present invention.
Preferable examples of commercially available photocleavable photoradical polymerization initiators include Irgacure (651, 184, 907) manufactured by Nippon Ciba-Geigy Co., Ltd.

  In addition to the photopolymerization initiator, a photosensitizer may be used. Specific examples of the photosensitizer include n-butylamine, triethylamine, tri-n-butylphosphine, Michler's ketone and thioxanthone.

In the case of curing with light, it is preferable to perform irradiation with active energy rays using a high-pressure mercury lamp or a 365 mm LED. At this time, it is preferable to irradiate with ultraviolet rays under a condition of oxygen concentration of 0.5% or less, more preferably a condition of oxygen concentration of 0.3% or less, and particularly preferably a condition of 0.2% or less. Preferably the irradiation energy in the range of ^{300mJ / cm 2 ~1500mJ / cm 2} , more preferably in the range of ^{400mJ / cm 2 ~1000mJ / cm 2} , particularly preferably of 500mJ / cm ² ~800mJ / cm ² It is a range.

  The amount of the compound that initiates radical polymerization by the action of heat or light may be any amount that can initiate polymerization of a carbon-carbon double bond, but in general, the total solid content in the curable resin composition 0.1-15 mass% is preferable with respect to this, More preferably, it is 0.5-10 mass%, Most preferably, it is 2-5 mass%.

The cured film made of the curable resin composition having the copolymer of the present invention forms a low refractive index layer and has both scratch resistance and can be used in various optical material applications. For example, it can be advantageously used for forming an optical material such as an antireflection film and an optical fiber clad material, and by utilizing the high fluorine content, a coating material and a weather resistant film for a substrate requiring weather resistance. It can also be suitably used as a material for coating, a material for coating, and the like. Among them, the use as an antireflection film is particularly useful, and the visibility can be improved by applying to various display devices.
Next, the application to an antireflection film having a low refractive index layer comprising the curable resin composition having the copolymer of the present invention (sometimes referred to as a low reflection laminate) will be described in detail.

Layer structure of antireflection film The antireflection film of the present invention can have various layer structures, but it has a hard coat layer, which will be described later, on a transparent substrate, and is reflected by optical interference thereon. The layers are laminated in consideration of the refractive index, the film thickness, the number of layers, the layer order, and the like so that the rate decreases. The simplest configuration of the low reflection laminate is a configuration in which only a low refractive index layer is coated on a substrate. In order to further reduce the reflectance, the antireflection layer is preferably composed of a combination of a high refractive index layer having a higher refractive index than the substrate and a low refractive index layer having a lower refractive index than the substrate.
The example of the preferable layer structure of the antireflection film of this invention is shown below. In the following configuration, the base film functions as a support.
・ Base film / low refractive index layer,
・ Base film / Antistatic layer / Low refractive index layer,
・ Base film / hard coat layer / high refractive index layer / low refractive index layer,
・ Base film / hard coat layer / antistatic layer / high refractive index layer / low refractive index layer,
Base film / hard coat layer / medium refractive index layer / high refractive index layer / low refractive index layer,
Base film / antistatic layer / hard coat layer / medium refractive index layer / high refractive index layer / low refractive index layer,
Antistatic layer / base film / hard coat layer / medium refractive index layer / high refractive index layer / low refractive index layer,
As long as the reflectance can be reduced by optical interference, it is not limited to these layer configurations.
The antistatic layer is preferably a layer containing conductive copolymer particles or metal oxide fine particles (for example, ATO, ITO), and can be provided by coating or atmospheric pressure plasma treatment.
Although the above example shows a configuration example of a so-called anti-glare film having no anti-glare property, it can be preferably applied to an anti-glare film having anti-glare property. In this case, it is possible to impart antiglare properties to any of the above layers.

[High / Medium Refractive Index Layer]
The material for forming the high / medium refractive index layer / hard coat layer of the antireflection film of the present invention will be described below.
The refractive index of the high / medium refractive index layer of the antireflection film of the present invention is preferably 1.50 to 2.40, more preferably 1.50 to 1.80.
The high / medium refractive index layer of the present invention contains at least a film-forming binder, and can further contain an inorganic filler in order to increase the refractive index of the layer and to reduce curing shrinkage.

The material for forming the high / medium refractive index layer of the present invention will be described below.
[Film-forming binder]
In the present invention, it is possible to use a compound having an ethylenically unsaturated group as a main film-forming binder component of a film-forming composition for forming each layer such as a high / medium refractive index layer. From the viewpoint of productivity and film productivity. The main film-forming binder refers to, for example, one that occupies 10% by mass or more of the film-forming components excluding inorganic fine particles. Preferably, they are 20 mass%-100 mass%, More preferably, they are 30 mass%-95 mass%.
A copolymer having a saturated hydrocarbon chain or a polyether chain as a main chain is preferable, and a copolymer having a saturated hydrocarbon chain as a main chain is more preferable. As the binder copolymer having a saturated hydrocarbon chain as the main chain and having a crosslinked structure, a polymer or copolymer of monomers having two or more ethylenically unsaturated groups is preferable.
In order to obtain a high refractive index, the monomer structure preferably contains an aromatic ring or at least one atom selected from halogen atoms other than fluorine, sulfur atoms, phosphorus atoms, and nitrogen atoms.

  Examples of the monomer having two or more ethylenically unsaturated groups include esters of polyhydric alcohol and (meth) acrylic acid (for example, ethylene glycol di (meth) acrylate, 1,4-cyclohexanediacrylate, pentaerythritol tetra ( (Meth) acrylate), pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, di Pentaerythritol hexa (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester Polyacrylate), vinylbenzene and derivatives thereof (for example, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinylsulfone (for example, divinylsulfone), acrylamide ( For example, methylenebisacrylamide) and methacrylamide. Two or more of these monomers may be used in combination. In the present specification, “(meth) acrylate” represents “acrylate or methacrylate”.

  Specific examples of the high refractive index monomer include bis (4-methacryloylthiophenyl) sulfide, vinyl naphthalene, vinyl phenyl sulfide, 4-methacryloxyphenyl-4′-methoxyphenyl thioether, and the like. Two or more of these monomers may be used in combination.

Polymerization of the monomer having an ethylenically unsaturated group can be performed by irradiation with ionizing radiation or heating in the presence of a photo radical initiator or a thermal radical initiator.
As the light and thermal radical polymerization initiator, those described above can be used.

In place of or in addition to a monomer having two or more ethylenically unsaturated groups, a monomer having a crosslinkable functional group is used to introduce a crosslinkable functional group into the copolymer, and the reaction of the crosslinkable functional group is performed. Thus, a crosslinked structure may be introduced into the binder copolymer.
Examples of the crosslinkable functional group include isocyanate group, epoxy group, aziridine group, oxazoline group, aldehyde group, carbonyl group, hydrazine group, carboxyl group, methylol group and active methylene group. Vinylsulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester and urethane, and metal alkoxide such as tetramethoxysilane can also be used as a monomer for introducing a crosslinked structure. A functional group that exhibits crosslinkability as a result of the decomposition reaction, such as a block isocyanate group, may be used. That is, in the present invention, the crosslinkable functional group may not react immediately but may exhibit reactivity as a result of decomposition.
These binder copolymers having a crosslinkable functional group can form a crosslinked structure by heating after coating. In the present invention, a copolymer having a polyether as the main chain can also be used. A ring-opening polymer of a polyfunctional epoxy compound is preferred. The ring-opening polymerization of the polyfunctional epoxy compound can be performed by irradiation with ionizing radiation or heating in the presence of a photoacid generator or a thermal acid generator. When the crosslinking reactive site of the copolymer has a group capable of cationic polymerization (epoxy group, oxetanyl group, oxazolyl group, vinyloxy group, etc.), it is preferable to add a polymerization initiator that generates an acid catalyst by light.

As examples of compounds that generate an acid by the action of light, various examples are described in, for example, “Organic Materials for Imaging” p187-198, JP-A-10-282644, edited by the Society for Organic Electronics Materials (Bunshin Publishing). These known compounds can be used. Specifically, RSO ₃ — (R represents an alkyl group or aryl group), AsF ₆ —, SbF ₆ —, PF ₆ —, BF ₄ — and the like, a diazonium salt, an ammonium salt, a phosphonium salt, Various onium salts such as iodonium salts, sulfonium salts, selenonium salts, arsonium salts, organic halides such as oxadiazole derivatives and S-triazine derivatives substituted with a trihalomethyl group, o-nitrobenzyl esters of organic acids, benzoin esters, Examples thereof include iminoesters and disulfone compounds, preferably onium salts, particularly preferably sulfonium salts and iodonium salts.

[Inorganic filler for high and medium refractive index layers]
The high refractive index layer includes an oxide of at least one metal selected from titanium, zirconium, aluminum, indium, zinc, tin, and antimony in order to increase the refractive index of the layer and to reduce cure shrinkage. And an inorganic filler having an average particle size of preferably 0.2 μm or less, more preferably 0.1 μm or less, and further preferably 0.06 μm or less.
Specific examples of the inorganic filler used in the high refractive index layer include TiO ₂ , ZrO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , a combination of ITO and SiO _2. Be TiO ₂ and ZrO ₂ are particularly preferable from the viewpoint of increasing the refractive index. The surface of the inorganic filler is preferably subjected to a silane coupling treatment or a titanium coupling treatment, and a surface treatment agent having a functional group capable of reacting with a binder species on the filler surface is preferably used.
The amount of these inorganic fillers added is preferably 10 to 90% of the total mass of the high refractive index layer, more preferably 20 to 80%, and even more preferably 30 to 70%.
Such a filler does not scatter because the particle size is sufficiently smaller than the wavelength of light, and the dispersion in which the filler is dispersed in the binder copolymer behaves as an optically uniform substance.

  The bulk refractive index of the mixture of the binder and the inorganic filler of the high refractive index layer of the present invention is preferably 1.48 to 2.00, more preferably 1.50 to 1.80. In order to make the refractive index within the above range, the kind and amount ratio of the binder and the inorganic filler may be appropriately selected. How to select can be easily known by conducting an experiment in advance.

  The antireflective film of the present invention has a lower refractive index than the high refractive index layer and a higher refractive index than the support. It is also preferable to provide a middle refractive index layer. The middle refractive index layer is a high refractive index used for the high refractive index layer. It can be formed in the same manner as the high refractive index layer by adjusting the amount of the refractive index filler or the high refractive index monomer used.

[Other layers]
The antireflection film may further be provided with a hard coat layer, a moisture proof layer, an antistatic layer, an undercoat layer or a protective layer. The hard coat layer is provided for imparting scratch resistance to the transparent support. The hard coat layer also has a function of strengthening the adhesion between the support and the layer thereon. The hard coat layer can be formed using an acrylic copolymer, a urethane copolymer, an epoxy copolymer, a silicon copolymer, a silica compound, or the like. A pigment may be added to the hard coat layer. The acrylic copolymer is preferably synthesized by a polymerization reaction of a polyfunctional acrylate monomer (for example, polyol acrylate, polyester acrylate, urethane acrylate, epoxy acrylate). Examples of the urethane copolymer include melamine polyurethane. As the silicon-based copolymer, a cohydrolyzate of a silane compound (for example, tetraalkoxysilane, alkyltrialkoxysilane) and a silane coupling agent having a reactive group (for example, epoxy, methacryl) is preferably used. Two or more kinds of copolymers may be used in combination. As the silica compound, colloidal silica is preferably used. The strength of the hard coat layer is a pencil hardness with a 1 kg load, preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher. On the support, in addition to the hard coat layer, an adhesive layer, a shield layer, a sliding layer and an antistatic layer may be provided. The shield layer is provided to shield electromagnetic waves and infrared rays.

The antireflection film of the present invention thus formed has a haze value of preferably 10% or less, more preferably 5% or less, and further preferably 3% or less, and an average reflectance of 450 nm to 650 nm, Preferably it is 3.0% or less, More preferably, it is 2.5% or less.
When the antireflection film of the present invention has a haze value and an average reflectance in the above range, antireflection properties can be obtained without causing deterioration of the transmitted image.

[Support]
A plastic film is preferably used as the support for the antireflection film of the present invention. As the copolymer forming the plastic film, cellulose ester (for example, triacetyl cellulose, diacetyl cellulose, typically TAC-TD80U, TD80UF, etc. manufactured by Fuji Photo Film Co., Ltd.), polyamide, polycarbonate, polyester (for example, polyethylene) Terephthalate, polyethylene naphthalate), polystyrene, polyolefin, norbornene resin (Arton: trade name, manufactured by JSR), amorphous polyolefin (ZEONEX: trade name, manufactured by ZEON Corporation), and the like. Of these, triacetyl cellulose, polyethylene terephthalate, and polyethylene naphthalate are preferable, and triacetyl cellulose is particularly preferable. In addition, the cellulose acylate film substantially free of halogenated hydrocarbons such as dichloromethane and the process for producing the same are disclosed in the JIII Journal of Technical Disclosure (Publication No. 2001-1745, published on March 15, 2001; The cellulose acylate described here can also be preferably used in the present invention.

 The antireflection film of the present invention can be preferably used as a protective film for a polarizing plate.

  The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[Method of measuring physical properties of copolymer]
Average molecular weight The average molecular weight of the copolymer was measured by gel permeation chromatography (GPC) by dissolving a part of the obtained copolymer in tetrahydrofuran (THF). The number average molecular weight (Mn) of the copolymer in the present invention is a value using polystyrene as a standard substance.
The apparatus is HLC-8220 (manufactured by Tosoh), the column is TSKgel SuperHZM-H (4.6 mmI.D. × 15 cm), TSKgel SuperHZ4000 (4.6 mmI.D. × 15 cm), TSKgel SuperHZ2000 (4.6 mmI.D). . × 15 cm 3) were connected and used.
The sample concentration was 2% by mass, the injection amount was 10 μl, and the flow rate was 0.35 ml / min.

Glass transition temperature (Tg)
Using a differential scanning calorimeter (product number: DSC6200, manufactured by Seiko Electronics Co., Ltd.), the temperature was raised at 10 ° C./min and measured.

Refractive Index Using a refractometer (DR-M2, manufactured by ATAGO), the refractive index was measured at an observation wavelength of 589 nm and a measurement temperature of 25 ° C.

[Method for evaluating cured film]
Average reflectance Using a spectrophotometer (manufactured by JASCO Corporation), the spectral reflectance at an incident angle of 5 ° was measured in a wavelength region of 380 to 780 nm. In Table 1 shown later, it represented with the mirror surface average reflectance of 450-650 nm.

Pencil Hardness Evaluation After the antireflection film was conditioned for 2 hours at a temperature of 25 ° C. and a humidity of 60% RH, the pencil hardness evaluation described in JIS K 5400 was performed.

Scratch resistance test The film surface was rubbed 10 times under a load of 200 g using steel wool # 0000, and then the level of scratching was confirmed. The determination was in accordance with the following criteria.
Not scratched at all: ◎
Slightly scratched: ○
Fine scratches stand out: △
Scratch is remarkable: ×

Fingerprint and magic adhesion evaluation As an index of surface contamination resistance, the optical material was conditioned for 2 hours at a temperature of 25 ° C and a humidity of 60% RH, and then the fingerprint was attached to the sample surface and then wiped off with a cleaning cloth. The state of the film was observed, and the fingerprint and magic adhesion were evaluated as follows.
Fingerprints can be wiped off completely: ◎
Some fingerprints are visible: ○
Fingerprints can hardly be wiped off: ×

Evaluation of white haze As an index to evaluate the uneven density of the inorganic fine particles in the low refractive layer, place the sample on black paper, apply diffuse white light from 50 cm directly above the sample, and observe the scattering unevenness of the sample And evaluated as follows.
Uniform observation without unevenness: ○
White scattering unevenness is observed in a part of the sample: Δ
White scattering unevenness is observed on one side of the sample: ×

[Copolymer Synthesis Example 1] Synthesis of fluorinated copolymer P-22 having a hydroxyl group in the side chain (3-2) 41.6 g (100 mmol), (5-1) 9.0 g in a 300 ml capacity flask 90 mmol), (C-3) 0.88 g (10 mmol), azo group-containing polydimethylsiloxane polymerization initiator VPS1001 (manufactured by Wako Pure Chemical Industries) 2.0 g, dimethyl 2,2′-azobis (2-methylpropionate) “V601” (manufactured by Wako Pure Chemical Industries, Ltd., 0.092 g (0.4 mmol)) was added, 50 g of methyl ethyl ketone was added thereto, and the solution was substituted with argon, followed by solution polymerization at 65 ° C. for 24 hours. The obtained copolymer solution was poured into hexane as it was, and reprecipitation purification was performed twice to obtain 39.1 g of a fluorinated copolymer. The obtained copolymer had Tg = 102 ° C., weight average molecular weight (Mw) = 58,000, and refractive index 1.385.

[Copolymer Synthesis Example 2] Synthesis of fluorinated copolymer P-24 having a hydroxyl group in the side chain (3-2) was changed to equimolar (3-1), and the same as copolymer synthesis example 1 Thus, 30.2 g of a copolymer was obtained as a white powder. The obtained copolymer had Tg = 94 ° C., weight average molecular weight (Mw) = 66,000, and refractive index 1.416.

[Example 1]
To 100 g of the 10 mass% MEK solution of (P-22) obtained in copolymer synthesis example 1, 1.5 g of methylated methylmelamine “Cymel 303” (manufactured by Mitsui Cytec Co., Ltd.) is added as a curing agent. The reaction was heated at 70 ° C. for 5 hours. Next, 0.1 g of p-toluenesulfonic acid as a curing catalyst was added thereto to prepare a low refractive index layer forming composition.
This low refractive index layer forming composition was diluted to a solid content of 6% by mass, and a hard coat layer (refractive index of 1.53) having a film thickness of 5 μm was provided on a support (TAC, manufactured by Fuji Photo Film Co., Ltd.). The material was applied using a wire bar coater (# 3) and heated at 120 ° C. for 60 minutes to form a 100 nm cured film. The evaluation results are shown in Table 1.

[Example 2]
A cured film was formed in the same manner as in Example 1 except that (P-22) was replaced with (P-24) of the same weight obtained in Copolymer Synthesis Example 2. The evaluation results are shown in Table 1.

[Comparative Example 1]
A low refractive index layer forming composition of Example 1 described in JP-A No. 11-228631 was prepared, and a cured film was formed in the same manner as in Example 1 below. The evaluation results are shown in Table 1.

[Copolymer Synthesis Example 3]
Fluorine-containing copolymer having methacryloyl group in side chain 20 g of copolymer (P-22) obtained in copolymer synthesis example 1 was dissolved in 100 ml of N, N-dimethylacetamide, and methacryloyl chloride (Wako Pure) After adding 5.0 g of (medicine) dropwise, the mixture was stirred at room temperature for 10 hours. Extraction with ethyl acetate was performed, and the organic phase was washed with water, concentrated, and reprecipitated in hexane. Furthermore, 13g of fluorine-containing copolymers were obtained as white powder by melt | dissolving in THF and reprecipitating with hexane. The weight average molecular weight (Mw) was 64000 and the refractive index was 1.392.

[Copolymer Synthesis Example 4]
A fluorine-containing copolymer was synthesized in the same manner as in the copolymer synthesis example 3, except that (P-22) was replaced with the same weight (P-24) obtained in the copolymer synthesis example 2. The obtained copolymer (white powder) was 13 g, weight average molecular weight (Mw) = 61000, and refractive index 1.421.

[Example 3]
0.5 g of Irgacure 907 (manufactured by Cigabaigie Co., Ltd.) was added as a photopolymerization initiator to 100 g of the 10 mass% MEK solution obtained in the above-mentioned copolymer synthesis example 3 to obtain a low refractive index layer forming composition. .
A wire bar coater (# 3) is used for a base material in which this low refractive index layer forming composition is diluted to a solid content of 6% by mass and a hard coat layer (refractive index of 1.53) having a film thickness of 5 μm is provided on TAC. And dried at 80 ° C. for 1 minute. Next, ultraviolet rays were irradiated in a nitrogen atmosphere to form a cured film. The evaluation results are shown in Table 1.

[Example 4]
A cured film was formed in the same manner as in Example 3 except that the copolymer used was changed to that obtained in the above-mentioned copolymer synthesis example 4. The evaluation results are shown in Table 1.

[Comparative Example 2]
A low refractive index layer forming composition of Reference Example 11 described in Japanese Patent Registration No. 3498381 was prepared, and a cured film was formed in the same manner as in Example 3 below. The evaluation results are shown in Table 1.

Claims (13)

A copolymer comprising a structural unit represented by the following general formula (1), a structural unit represented by the following general formula (2), and a structural unit represented by the following general formula (3).
General formula (1)

(In general formula (1), R ¹ and R ² each represents an alkyl group or an aryl group, and at least one of R ¹ and R ² contains a fluorine atom.)
General formula (2)

(In general formula (2), R ³ and R ⁴ each represent a hydrogen atom, an alkyl group or an aryl group.)
General formula (3)

(In general formula (3), R ⁵ represents an alkyl group, an aryl group, an alkoxy group or an amino group (including an anilino group), and R ⁶ represents an alkyl group.) The structural unit represented by the general formula (1) is 20 mol% or more, the structural unit represented by the general formula (2) is 0.05 mol% or more, and the structural unit represented by the general formula (3). the copolymer according to claim 1 containing 20% molar or more. 3. The co-polymerization according to claim 1, wherein at least one of R ¹ and R ^{2 in} the general formula (1) is a C 2-6 alkyl group containing a fluorine atom or an aryl group containing a fluorine atom. Polymer. The copolymer according to any one of claims 1 to 3 , wherein R ⁵ and R ⁶ in the general formula (3) are both methyl groups. The copolymer according to any one of claims 1 to 4 , which has a weight average molecular weight of 2,000 to 1,000,000. A polymerizable composition comprising a compound represented by the following general formula (4), a compound represented by the following general formula (5), and a polysiloxane-containing compound.
General formula (4)

(In general formula (4), R ¹ and R ² each represents an alkyl group or an aryl group, and at least one of R ¹ and R ² contains a fluorine atom.)
General formula (5)

(In general formula (5), R ⁵ represents an alkyl group, an aryl group, an alkoxy group or an amino group (including an anilino group), and R ⁶ represents an alkyl group.) The polymerizable composition according to claim 6 , wherein at least one of R ¹ and R ^{2 in} the general formula (4) is a C 2-6 alkyl group containing a fluorine atom or an aryl group containing a fluorine atom. object. The polymerizable composition according to claim 6 or 7 , wherein R ⁵ and R ^{6 in} the general formula (5) are both methyl groups. A curable resin composition comprising the copolymer according to any one of claims 1 to 5 and a solvent. A cured film comprising the curable resin composition according to claim 9 . The antireflection film which has a low-refractive-index layer which consists of a cured film which uses the curable resin composition of Claim 9 . A polarizing plate comprising a polarizer and a protective film provided on at least one side of the polarizer, wherein the protective film is the antireflection film according to claim 11 . An image display device comprising the antireflection film according to claim 11 .