JP2006257308A - Hollow silica particle dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of dispersing hollow silica particles well in an organic solvent. <P>SOLUTION: In this method, a polymer having a hydrocarbon main chain is covalently bonded to the hollow silica particle dispersed in an organic solvent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hollow silica particle dispersion in which hollow silica particles are dispersed in an organic solvent. The present invention also relates to a method for producing hollow silica particles. Furthermore, the present invention also relates to an optical film, an antireflection film, a polarizing plate and a display device that can be produced using a hollow silica particle dispersion.

In general, an antireflection film is used for 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 reflection due to reflection of external light. In order to prevent engraving, it is placed on the outermost surface of the display so as to reduce reflectivity using the principle of optical interference. Such an antireflection film is produced by forming a low refractive index layer having an appropriate thickness on the outermost surface, and optionally a high refractive index layer, a middle refractive index layer, a hard coat layer, etc. between the support and the support. it can.
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. At the same time, since it is used on the outermost surface of the display, high scratch resistance is also required. 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 the material, there are means of introducing fluorine atoms and lowering the density (introducing voids), both of which are in a direction in which the film strength and adhesion are impaired and the scratch resistance is lowered. .

  Here, by adding inorganic particles to organic materials such as adhesives, exterior paints, hard coats, and antireflection films, the scratch resistance, the strength of the cured product, and the ability to adhere to other materials that have come into contact are improved. It is well known that However, when blending inorganic particles in an organic material, it is necessary that the inorganic particles do not cause unnecessary aggregation.

  Patent Document 1 describes means for lowering the refractive index by employing hollow silica particles in the low refractive index layer of the antireflection film. However, the hollow silica particles easily aggregate in an organic material, and a uniform dispersion or It was difficult to obtain a coating surface.

  In general, prevention of aggregation of inorganic particles is achieved by controlling hydrophilicity / hydrophobicity and steric hindrance on the surface of inorganic particles, and in particular, surface treatment using alkoxysilane is known for inorganic oxide particles.

For example, Non-Patent Document 1 describes a method of dispersing inorganic particles in an organic solvent using a silane coupling agent. However, it was still insufficient in terms of the stability of the dispersion. In particular, in the combination of polymerization-curing organic materials and inorganic particles, alkoxysilanes containing a polymerization group and / or hydrolysis condensates thereof have attracted attention.
For example, Patent Document 2 proposes the combined use of a specific polyalkoxypolysiloxane and a polymerizable silane coupling agent, but the reaction between the polyalkoxypolysiloxane and the polymerizable silane coupling agent proceeds sufficiently. Since it is difficult, the introduction rate of the polymerizable group is low, and the scratch resistance and strength of the cured product are not sufficient. Patent Document 3 reports a partial cohydrolysis condensate of an alkoxysilane containing an organic functional group and a tetraalkoxysilane, but the dispersion stability of the inorganic particles is not sufficient.

  Non-Patent Document 2 describes that the dispersion stability of the magnetite particles obtained by surface graft polymerization from the surface of the magnetite particles, the surfaces of which are modified with polymer chains, in an organic solvent is remarkably improved. However, the refractive index of magnetite particles is not low and is not suitable for use as a low refractive index material.

  Thus, the compatibility between the low refractive index and the high scratch resistance has not been realized yet, which has been a difficult problem.

JP 2001-233611 A JP-A-9-169847 Japanese Patent Laid-Open No. 9-40909 "Pigment Dispersion Technology Surface Treatment, Dispersant Usage and Dispersibility Evaluation" (Technical Information Association, 1999 edition) “Polymer 45 (2004) P. 2231”

An object of the present invention is to provide a hollow silica particle dispersion in which hollow silica particles are well dispersed in an organic solvent.
Another object of the present invention is to provide a hollow silica particle dispersion useful as a coating composition.
Furthermore, an object of the present invention is to provide an optical film having high scratch resistance.

Still another object of the present invention is to provide an antireflection film having sufficient antireflection performance and excellent scratch resistance.
Another object of the present invention is to provide a polarizing plate having an effective anti-reflection film.
Still another object of the present invention is to provide a display device capable of displaying a good image.

The problems of the present invention have been solved by the following [1] to [16].
[1] A hollow silica particle dispersion in which hollow silica particles are dispersed in an organic solvent, wherein a polymer having a hydrocarbon main chain is covalently bonded to silica on the surface of the hollow silica particles. Hollow silica particle dispersion.

[2] The hollow silica particle dispersion according to [1], wherein the silica on the surface of the hollow silica particle and the polymer having a hydrocarbon main chain are directly covalently bonded.
[3] A binder is interposed between the silica on the surface of the hollow silica particles and the polymer having a hydrocarbon main chain. The silica and the binder are covalently bonded, and the binder and the polymer are covalently bonded. The hollow silica particle dispersion according to [1].
[4] The hollow silica particle dispersion according to [1], wherein the polymer having a hydrocarbon main chain has a crosslinkable group.
[5] The hollow silica particle dispersion according to [4], wherein the polymer having a hydrocarbon main chain includes a repeating unit represented by the following formula (1):

[Wherein R ¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Y is a single bond or a divalent linking group; and G is a crosslinkable group].
[6] The hollow silica particle dispersion according to [5], wherein in formula (1), G is an acryloyloxy group, a methacryloyloxy group or an epoxy group.
[7] The hollow silica particle dispersion according to [1], further comprising a curable resin.
[8] The hollow silica particle dispersion according to [7], wherein the curable resin comprises a polymer or monomer having an ethylenically unsaturated group or an epoxy group.

[9] A hollow silica particle in which a polymer having a hydrocarbon main chain is covalently bonded to a surface silica by polymerizing an ethylenically unsaturated polymerizable compound from the surface silica of the hollow silica particle. A method for producing hollow silica particles.
[10] The method for producing hollow silica particles according to [9], wherein the polymer having a hydrocarbon main chain covalently bonded to the surface silica is further subjected to a reaction for introducing a crosslinkable group.

[11] The method for producing hollow silica particles according to [9], wherein the ethylenically unsaturated polymerizable compound is graft-polymerized from a functional group having a polymerization initiating ability covalently bonded to silica on the surface of the hollow silica particles.
[12] The method for producing hollow silica particles according to [9], wherein the ethylenically unsaturated polymerizable compound is graft-polymerized from a functional group having a chain transfer ability covalently bonded to silica on the surface of the hollow silica particles.

[13] An optical film having a cured coating containing a transparent support and hollow silica particles, wherein the cured coating containing hollow silica particles is dispersed in an organic solvent, and the surface of the hollow silica particles is An optical film, characterized in that it is a film obtained by curing a hollow silica particle dispersion containing a curable resin, wherein a polymer having a hydrocarbon main chain is covalently bonded to silica.
[14] An antireflective film having a transparent support and a low refractive index layer, wherein the low refractive index layer has hollow silica particles dispersed in an organic solvent, and hydrocarbons are mainly contained in silica on the surface of the hollow silica particles. An antireflective film comprising a coating obtained by curing a hollow silica particle dispersion containing a curable resin, wherein a polymer having a chain is covalently bonded.

[15] A polarizing plate comprising a polarizing film and two protective films disposed on both sides of the polarizing film, wherein at least one of the protective films has hollow silica particles dispersed in an organic solvent. A polarizing plate characterized in that a polymer having a hydrocarbon main chain is covalently bonded to silica on the surface, and further has a film obtained by curing a hollow silica particle dispersion containing a curable resin.
[16] A display device in which a coating is provided on the outermost surface of the display, wherein the coating has hollow silica particles dispersed in an organic solvent, and the silica on the surface of the hollow silica particles has a hydrocarbon main chain. A display device, wherein the polymer is covalently bonded and is a film obtained by curing a hollow silica particle dispersion containing a curable resin.

  In the present specification, the description “numerical value A” to “numerical value B” representing physical property values and characteristic values represents the meaning of “numerical value A to numerical value B”.

The hollow silica particles according to the present invention have improved dispersibility in an organic solvent by covalently bonding a polymer having a hydrocarbon main chain to the surface silica. Therefore, the hollow silica particle dispersion according to the present invention is excellent in stability as a dispersion.
A dispersion in which hollow silica particles are well dispersed is useful as a coating composition. A film formed using such a coating composition has the effect of high scratch resistance. The film in which the hollow silica particles are well dispersed has an excellent optical function (eg, antireflection function). Therefore, the optical film, the antireflection film, the polarizing plate and the display device according to the present invention are excellent in both the optical function such as the antireflection performance and the scratch resistance.

[Covalent bond between hollow silica particle surface and polymer]
In the hollow silica particles, a polymer having a hydrocarbon main chain is covalently bonded to the surface silica.
The silica on the surface of the hollow silica particles and the polymer having a hydrocarbon main chain can be directly covalently bonded.
Further, a binder may be interposed between the silica on the surface of the hollow silica particles and the polymer having a hydrocarbon main chain, and the silica and the binder may be covalently bonded, and the binder and the polymer may be covalently bonded. As the binder, a coupling agent is preferably used.

The hollow silica particles according to the present invention are obtained by reacting a polymer having a functional group capable of forming a covalent bond with the hollow silica particle surface in a state where the hollow silica particle surface is untreated or treated with a coupling agent or the like. A method of grafting a polymer to the surface of silica particles, or 2) polymer chains are grown by polymerizing monomers from the surface of hollow silica particles in a state where the surface of hollow silica particles is untreated or treated with a coupling agent, etc. And surface grafting.
From the viewpoint of improving the surface modification rate, a method of polymerizing monomers from the surface of the hollow silica particles to grow a polymer chain and surface grafting is preferable. More preferred is a method in which hollow silica is surface-treated with a coupling agent containing a functional group having a polymerization initiating ability or a chain transfer ability, a monomer is polymerized therefrom, and a polymer chain is grown to carry out surface grafting.

[Introduction of functional group having polymerization initiating ability or chain transfer ability to hollow silica surface]
An alkoxy metal compound (eg, titanium coupling agent, silane coupling agent) is preferably used as a surface treatment agent (coupling agent) for introducing a functional group having a polymerization initiating ability or a chain transfer ability onto the hollow silica surface. . Treatment with a silane coupling agent is effective, and a silane coupling agent represented by the following formula [4] is particularly effective.

_{^{[4] (Z-L 1}} ) m -Si- (R 2) n R 3 (4-m + n)

In the formula [4], Z is a functional group having a polymerization initiating ability or a chain transfer ability.
In the formula [4], L ¹ is a divalent linking group having 10 or less carbon atoms.
L ¹ is preferably an alkylene group having 1 to 10 carbon atoms, or a group in which a plurality of alkylene groups are bonded via a linking group (eg, ether, ester, amide). The alkylene group may have a branch. The alkylene group may have a substituent. Examples of the substituent include a halogen atom, hydroxyl, mercapto, carboxyl, epoxy group, alkyl group, and aryl group.

In the formula [4], R ² is an alkyl group having 1 to 10 carbon atoms.
In the formula [4], R ³ is hydroxyl or a hydrolyzable group. R ³ is preferably an alkoxy group having 1 to 5 carbon atoms or a halogen atom, and more preferably a methoxy, ethoxy or chlorine atom.
In the formula [4], 1 ≦ m ≦ 3, 0 ≦ n ≦ 2, and 1 ≦ m + n ≦ 3.

  Examples of the substituent that the silane coupling agent represented by the formula [4] can have include hydroxyl, halogen atom (eg, Cl, Br, F, I), cyano, nitro, carboxyl, sulfo, carbon atom number 1-8 alkyl groups (eg, methyl, ethyl, isopropyl, butyl, hexyl, cyclopropyl, cyclohexyl, 2-hydroxyethyl, 4-carboxybutyl, 2-methoxyethyl, 2-diethylaminoethyl), 2 to 2 carbon atoms 8 alkenyl groups (eg, vinyl, allyl, 2-hexenyl), alkynyl groups having 2 to 8 carbon atoms (eg, ethynyl, 1-butynyl, 3-hexynyl), aralkyl groups having 7 to 12 carbon atoms (eg, Benzyl, phenethyl), an aryl group having 6 to 10 carbon atoms (eg, phenyl, naphthyl, 4-carboxyphenyl, 4-a Toamidophenyl, 3-methanesulfonamidophenyl, 4-methoxyphenyl, 3-carboxyphenyl, 3,5-dicarboxyphenyl, 4-methanesulfonamidophenyl, 4-butanesulfonamidophenyl), 1 to 10 carbon atoms Acyl groups (eg, acetyl, benzoyl, propanoyl, butanoyl), alkoxycarbonyl groups having 2 to 10 carbon atoms (eg, methoxycarbonyl, ethoxycarbonyl), and aryloxycarbonyl groups having 7 to 12 carbon atoms (eg, phenoxy) Carbonyl, naphthoxycarbonyl), a carbamoyl group having 1 to 10 carbon atoms (eg, unsubstituted carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl), an alkoxy group having 1 to 8 carbon atoms (eg, methoxy, ethoxy, Butoxy, me Xyloxy), aryloxy group having 6 to 12 carbon atoms (eg, phenoxy, 4-carboxyphenoxy, 3-methylphenoxy, naphthoxy), acyloxy group having 2 to 12 carbon atoms (eg, acetoxy, benzoyloxy), carbon atom A sulfonyloxy group having 1 to 12 (eg, methylsulfonyloxy, phenylsulfonyloxy), amino, a substituted amino group having 1 to 10 carbon atoms (eg, dimethylamino, diethylamino, 2-carboxyethylamino), the number of carbon atoms 1 to 10 amide groups (eg, acetamide, benzamide), sulfonamido groups having 1 to 8 carbon atoms (eg, methanesulfonamide, benzenesulfonamide, butanesulfonamide, octanesulfonamide), 1 to 10 carbon atoms Ureido groups (eg, ureido, methylureido) , An alkoxycarbonylamino group having 2 to 10 carbon atoms (eg, methoxycarbonylamino, ethoxycarbonylamino), an alkylthio group having 1 to 12 carbon atoms (eg, methylthio, ethylthio, octylthio), 6 to 12 carbon atoms Arylthio group (eg, phenylthio, naphthylthio), alkylsulfonyl group having 1 to 8 carbon atoms (eg, methylsulfonyl, butylsulfonyl), arylsulfonyl group having 7 to 12 carbon atoms (eg, phenylsulfonyl, 2-naphthylsulfonyl) ), Sulfamoyl, substituted sulfamoyl groups having 1 to 8 carbon atoms (eg, methylsulfamoyl), heterocyclic groups (eg, 4-pyridyl, piperidino, 2-furyl, furfuryl, 2-thienyl, 2-pyrrolyl, 2 -Quinolylmorpholino).

  A silane coupling agent represented by the following formula [5] is more preferred.

[5] Z— (CH ₂ ) _n —Si—R ⁴ ₃

In the formula, Z is the same as above, and n represents an integer of 1 to 10. R ⁴ represents an alkoxy group having 1 to 5 carbon atoms or a halogen atom, preferably methoxy, ethoxy, and chlorine atoms.

  Z in the formulas [4] and [5] is a functional group having a polymerization initiating ability or a chain transfer ability, and has a polymerization initiator used in a normal polymerization reaction or a partial structure of a chain transfer agent. Preferably there is. For example, in the case of a free radical polymerization method, it is preferable that Z contains an azo group or a peracid site. When a functional group having a polymerization initiating ability is introduced onto the hollow silica surface, the applicable polymerization method is not limited, such as radical polymerization method and ionic polymerization method, but radical polymerization method is preferable, and living radical polymerization method is more preferable. Among them, it is more preferable to perform surface graft polymerization by an atom transfer radical polymerization method.

  Here, in the case of the atom transfer radical polymerization method which is the above preferable polymerization method, Z is preferably a halomethyl group, a haloalkylphenyl group, an α-haloester group, an α-halocarbonyl group, an α-halonitrile group or a halosulfonyl group. Further, an α-haloester group and a halosulfonyl group are more preferable, and an α-haloester group is particularly preferable. Various initiators are shown in the initiator section in Matyjaszewski, Xia, “Chemical Review” (2001, 101, No. 9, P2921). When using an atom transfer radical polymerization method, All are preferred when Z has the initiator partial structure shown here.

  The preferable example of the silane coupling agent containing the functional group which has the polymerization initiating ability represented by Formula [4] is given.

XCH ₂ C (O) O (CH ₂ ) ₃ Si (OCH ₃ ) ₃ , CH ₃ C (H) (X) C (O) O (CH ₂ ) ₃ Si (OCH ₃ ) ₃ , (CH ₃ ) ₂ C (X) C (O) O (CH ₂ ) ₃ Si (OCH ₃ ) ₃ , XCH ₂ C (O) O (CH ₂ ) ₆ Si (OCH ₃ ) ₃ , CH ₃ C (H) (X) C _{(O) O (CH 2)} 6 Si (OCH 3) 3, (CH 3) 2 C (X) C (O) O (CH 2) 6 Si (OCH 3) 3, XCH 2 C (O) O ( _{CH 2) 3 Si (OC 2} H 5) 3, CH 3 C (H) (X) C (O) O (CH 2) 3 Si (OC 2 H 5) 3, (CH 3) 2 C (X) _{C (O) O (CH 2} ) 3 Si (OC 2 H 5) 3, XCH 2 C (O) O (CH 2) 6 Si (OC 2 H 5) 3, CH 3 C _{H) (X) C (O} ) O (CH 2) 6 Si (OC 2 H 5) 3, (CH 3) 2 C (X) C (O) O (CH 2) 6 Si (OC 2 H 5) ₃ , XCH ₂ C (O) O (CH ₂ ) ₃ SiCl ₃ , CH ₃ C (H) (X) C (O) O (CH ₂ ) ₃ SiCl ₃ , (CH ₃ ) ₂ C (X) C ( O) O (CH ₂ ) ₃ SiCl ₃ (In each formula, X is a chlorine, bromine or iodine atom, with a bromine atom being particularly preferred.)

  The silane coupling agent represented by the formula [4] is preferably used in an amount of 1% by mass to 100% by mass with respect to the hollow silica, more preferably 2% by mass to 80% by mass, and still more preferably 5% by mass. % To 50% by mass.

Two or more silane coupling agents may be used in combination. The total addition amount of the two or more silane coupling agents is preferably 1% by mass to 100% by mass with respect to the hollow silica, more preferably 2% by mass to 80% by mass, and even more preferably 5%. It is mass%-50 mass%. Moreover, when using several silane coupling agents, you may add all the silane coupling agents simultaneously. Moreover, after adding one or more silane coupling agents and advancing reaction, you may add the remaining silane coupling agents.
It is also preferable to prepare a partial condensate with a silane coupling agent in advance and then add it to the hollow silica.

  The silane coupling agent can be allowed to act on the hollow silica surface to introduce a functional group having a polymerization initiating ability. Specifically, components derived from the silane coupling agent are bonded to the hollow silica surface by hydrolysis reaction, condensation reaction or both reactions of the silane coupling agent.

Hydrolysis / condensation reaction of the silane coupling agent is 0.3 to 2.0 mol, preferably 0.5 to 1.0 mol of water with respect to 1 mol of the hydrolyzable group (R ^{3 in} formula (4)). And stirring at 15 to 100 ° C. in the presence of an acid catalyst or a metal chelate compound.

[Solvent in functional group introduction treatment having polymerization initiation ability]
The functional group introduction treatment with the hydrolyzate or condensation reaction product of the silane coupling agent can be performed without a solvent or in a solvent. When a solvent is used, the concentration of the hydrolyzate of the silane coupling agent and / or the partial condensate thereof can be appropriately determined. As the solvent, an organic solvent is preferably used in order to uniformly mix the components. As the organic solvent, alcohol, aromatic hydrocarbon, ether, ketone and ester are preferable.

  The solvent is preferably a solvent that dissolves the hydrolyzate and / or condensation reaction product of the silane coupling agent and the catalyst. In addition, it is preferable in the process that an organic solvent is used as a coating solution or a part of the coating solution, and those that do not impair the solubility or dispersibility when mixed with other materials such as a fluorine-containing polymer are preferable.

  The alcohol is preferably a monohydric alcohol or a dihydric alcohol. The monohydric alcohol is preferably a saturated aliphatic alcohol having 1 to 8 carbon atoms. Examples of alcohols include methanol, ethanol, propyl alcohol, isopropyl alcohol, butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, ethylene glycol monobutyl ether, and ethylene glycol monoethyl ether acetate. Including.

Examples of aromatic hydrocarbons include benzene, toluene, xylene.
Examples of the ether include tetrahydrofuran and dioxane.
Examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone.
Examples of esters include ethyl acetate, propyl acetate, butyl acetate, propylene carbonate.

  Two or more organic solvents can be used in combination. The concentration of organosilane with respect to the organic solvent is preferably in the range of 0.1% by mass to 70% by mass, and more preferably in the range of 1% by mass to 50% by mass.

[Catalyst in functional group introduction treatment having polymerization initiation ability]
The functional group introduction treatment having a polymerization initiating ability or a chain transfer ability with a hydrolyzate and / or condensation reaction product of a silane coupling agent is preferably performed in the presence of a catalyst.

As catalysts, inorganic acids (eg, hydrochloric acid, sulfuric acid, nitric acid), organic acids (eg, oxalic acid, acetic acid, formic acid, methanesulfonic acid, toluenesulfonic acid), inorganic bases (eg, sodium hydroxide, potassium hydroxide, ammonia) ), Organic bases (eg, triethylamine, pyridine), metal chelate compounds, and metal alkoxides (eg, triisopropoxyaluminum, tetrabutoxyzirconium) can be used. Examples of the central metal of the metal chelate compound are zirconium, titanium, and aluminum.
From the viewpoint of production stability and storage stability of the hollow silica particle dispersion, an acid catalyst (inorganic acid, organic acid) and a metal chelate compound are preferable. The inorganic acid is preferably hydrochloric acid or sulfuric acid. The organic acid preferably has an acid dissociation constant in water (pKa value (25 ° C.)) of 4.5 or less. An organic acid having an acid dissociation constant of 3.0 or less in hydrochloric acid, sulfuric acid and water is preferable, an organic acid having an acid dissociation constant of 2.5 or less in hydrochloric acid, sulfuric acid and water is more preferable, and an acid dissociation constant in water is An organic acid of 2.5 or less is more preferable, methanesulfonic acid, oxalic acid, phthalic acid, and malonic acid are still more preferable, and oxalic acid is most preferable.

  When the hydrolyzable group of the silane coupling agent is an alkoxy group and the acid catalyst is an organic acid, the amount of water added can be reduced because the carboxyl group or sulfo group of the organic acid supplies protons. The amount of water added to 1 mol of the alkoxide group of the organosilane is 0 to 2 mol, preferably 0 to 1.5 mol, more preferably 0 to 1 mol, and particularly preferably 0 to 0.5 mol. is there. When alcohol is used as a solvent, it is not necessary to substantially add water.

  The amount of the acid catalyst used is 0.01 to 10 mol%, preferably 0.1 to 5 mol%, based on the hydrolyzable group when the acid catalyst is an inorganic acid, and the acid catalyst is an organic acid. However, when water is added, the optimal amount of use is 0.01 to 10 mol%, preferably 0.1 to 5 mol%, based on the hydrolyzable group. When substantially no water is added, it is 1 to 500 mol%, preferably 10 to 200 mol%, more preferably 20 to 200 mol%, still more preferably 50 to 50 mol% with respect to the hydrolyzable group. 150 mol%, particularly preferably 50 to 120 mol%.

  The treatment is performed by stirring at 15 to 100 ° C. The treatment conditions are preferably adjusted by the reactivity of the silane coupling agent.

[Metal chelate compounds]
The metal chelate compound is an alcohol represented by the formula R ⁵ OH (wherein R ⁵ is an alkyl group having 1 to 10 carbon atoms) or a formula R ⁶ COCH ₂ COR ⁷ (wherein R ⁶ is a carbon atom) Zr having a ligand of a compound represented by an alkyl group having 1 to 10 carbon atoms, and R ⁷ is an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms. A compound having a metal selected from Ti or Al as a central metal is preferable. Two or more metal chelate compounds may be used in combination.
The metal chelate compound represented by the following formula has a function of promoting the condensation reaction of the silane coupling agent, and is preferable.
Zr (OR ⁵ ) _p1 (R ⁶ COCHCOR ⁷ ) _p2
Ti (OR ⁵ ) _q1 (R ⁶ COCHCOR ⁷ ) _q2
Al (OR ⁵ ) _r1 (R ⁶ COCHCOR ⁷ ) _r2

R ⁵ and R ⁶ in the metal chelate compound are each independently an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms. Examples of alkyl groups include ethyl, propyl, isopropyl, butyl, sec-butyl, t-butyl, pentyl. Examples of aryl groups include phenyl.
However, R ⁵ represents an alkoxy group having 1 to 10 carbon atoms (eg, methoxy, ethoxy, propoxy group, isopropoxy) in addition to an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms. , Butoxy, sec-butoxy, t-butoxy).
P1, p2, q1, q2, r1 and r2 in the metal chelate compound represent integers determined so as to be tetradentate or hexadentate.

  Examples of metal chelate compounds are tributoxyethyl acetoacetate zirconium, dibutoxybis (ethylacetoacetate) zirconium, butoxytris (ethylacetoacetate) zirconium, tetrakis (propylacetoacetate) zirconium, tetrakis (acetylacetoacetate) zirconium, tetrakis (ethyl) Zirconium chelate compounds such as acetoacetate) zirconium; Titanium chelate compounds such as diisopropoxy bis (ethylacetoacetate) titanium, diisopropoxy bis (acetylacetate) titanium, diisopropoxy bis (acetylacetone) titanium; Propoxyethyl acetoacetate aluminum, diisopropoxyacetylacetonate aluminium , Isopropoxybis (ethylacetoacetate) aluminum, isopropoxybis (acetylacetonate) aluminum, tris (ethylacetoacetate) aluminum, tris (acetylacetonate) aluminum, monoacetylacetonate bis (ethylacetoacetate) aluminum, etc. Of aluminum chelate compounds.

  The metal chelate compound is preferably tributoxyethyl acetoacetate zirconium, diisopropoxybis (acetylacetonate) titanium, diisopropoxyethyl acetoacetate aluminum, or tris (ethyl acetoacetate) aluminum. Two or more metal chelate compounds may be used in combination. A partial hydrolyzate of a metal chelate compound can also be used.

  The metal chelate compound is preferably 0.01 to 50% by mass, more preferably 0.1 to 50% by mass, more preferably 0.1 to 50% by mass, based on the organosilane, from the viewpoint of the speed of the condensation reaction and the film strength when it is used as a coating film. More preferably, it is used at a ratio of 0.5 to 10% by mass.

  When Z is a functional group having chain transfer ability, the polymerization method is not limited, but radical polymerization method and ionic polymerization method are preferable, and radical polymerization method is more preferable.

Although it does not limit as a functional group which has chain transfer ability, A halomethyl group and a mercapto group are preferable, and a mercapto group is more preferable.

  Examples of the silane coupling agent represented by the formula [4] when Z is a functional group having chain transfer ability are shown.

HSCH ₂ Si (OCH ₃ ) ₃ , HS (CH ₂ ) ₃ Si (OCH ₃ ) ₃ , HS (CH ₂ ) ₃ Si (CH ₃ ) (OCH ₃ ) ₂ , HS (CH ₂ ) ₃ Si (OC ₂ H _{5) 3, HS (CH 2} ) 3 Si (CH 3) (OC 2 H 5) 2

  The solvent, catalyst, and metal chelate compound used when introducing the functional group having chain transfer ability onto the hollow silica surface are preferably used in the same manner as when introducing the functional group having polymerization initiation ability. The same applies to the range of preferable conditions.

  The hollow silica having a functional group capable of initiating polymerization or chain transfer introduced on the surface may be used after being purified and isolated, or the reaction mixture obtained without purification may be used as it is. is there. Examples of the purification treatment include ultracentrifugation. It is preferable to purify the hollow silica by sedimentation by ultracentrifugation, and discarding the supernatant and redispersing in the solvent several times.

[Method of surface graft polymerization]
The polymerization can be carried out in the absence of a solvent or in a solvent.
Solvents are hydrocarbon (eg, benzene, toluene), ether (eg, diethyl ether, tetrahydrofuran), halogenated hydrocarbon (eg, methylene chloride, chloroform), ketone (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone), alcohol (Eg, methanol, ethanol, propanol, isopropanol, butyl alcohol, tert-butyl alcohol), nitrile (eg, acetonitrile, propionitrile, benzonitrile), ester (eg, ethyl acetate, butyl acetate, ethylene carbonate, propylene carbonate) Can be used. Two or more solvents can be mixed and used.

  The polymerization temperature is preferably in the range of 0 ° C to 200 ° C, and more preferably in the range of 20 to 150 ° C.

[Polymer having hydrocarbon main chain]
The polymer having a hydrocarbon main chain can be synthesized using an ethylenically unsaturated polymerizable compound as a monomer. The monomer is preferably a (meth) acrylic acid monomer, an amide group-containing monomer, or a vinyl ether monomer, and more preferably a (meth) acrylic acid monomer, from the viewpoint of ease of polymerization and physical properties of the resulting product. More preferred is a (meth) acrylic acid ester monomer.
These preferred monomers may be copolymerized with other monomers. As long as the monomer has polymerizability, it may have a reactive functional group. Examples of reactive functional groups include halogen atoms, hydroxyl, carboxyl, epoxy groups, amino, mercapto. Furthermore, another kind of functional group can also be introduced into the polymer by performing a polymer-low molecular reaction using these functional groups.

  When hollow silica having a polymer on the surface is used as the coating composition, it is preferable to impart scratch resistance. In particular, when employed in the low refractive index layer of the antireflection film, it is preferable to introduce a crosslinkable group for the purpose of enhancing the scratch resistance of the antireflection film. The polymer having a crosslinkable group in the side chain is represented by the following formula ( It is preferable that the repeating unit represented by 1) is included.

In the formula (1), R ¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. R ¹ is preferably a hydrogen atom or a methyl group.
In the formula (1), Y is a single bond or a divalent linking group. The divalent linking group is preferably —CO—, —O—, —NH—, an alkylene group, or a combination thereof. The alkylene group preferably has 1 to 6 carbon atoms. The divalent linking group composed of the combination is preferably —CO—O—, —CO—O—AL— or —CO—O—AL—O—. AL is an alkylene group.

In the formula (1), G is a crosslinkable group. The crosslinkable group is preferably a functional group that can form a covalent bond with another molecule.
The crosslinkable group is preferably subjected to a crosslinking reaction by active species (radical, acid) generated by heating, ionizing radiation irradiation, or heating or ionizing radiation irradiation.
Examples of the crosslinkable group include an acryloyloxy group, a methacryloyloxy group, an epoxy group, an isocyanate group, an aziridine group, and an oxazoline group. From the viewpoint of crosslinking efficiency and ease of handling, an acryloyloxy group, a methacryloyloxy group, and an epoxy group are preferable, and an acryloyloxy group and a methacryloyloxy group are more preferable.

The crosslinkable group can be introduced into the polymer by polymerizing a monomer having a crosslinkable group.
Moreover, it can also introduce | transduce by performing a polymer reaction using a reactive functional group. For example, after synthesizing a polymer having a hydroxyl group, an acid halide (acrylic acid chloride, methacrylic acid chloride), an acid anhydride (acrylic acid anhydride, methacrylic acid anhydride) or an acid itself (acrylic acid, methacrylic acid) acts. By doing so, an acryloyl group or a methacryloyl group can be introduced into the polymer as a crosslinkable group.
Alternatively, a polymer having a crosslinkable group can be formed by a method in which a vinyl monomer having a 3-chloropropionic acid ester moiety is polymerized and then dehydrochlorinated.

  Hereinafter, the repeating unit which has a crosslinkable group represented by Formula (1) in a side chain is illustrated.

A homopolymer consisting of only a repeating unit having a crosslinkable group represented by the formula (1) in the side chain can be used. You may use the copolymer which has 2 or more types of repeating units which have a crosslinkable group represented by Formula (1) in a side chain.
You may use the copolymer which consists of a repeating unit which has a crosslinkable group represented by Formula (1) in a side chain, and another repeating unit. In the case of a copolymer, the ratio of the repeating unit represented by the formula (1) is in the range of 10 to 99.9 mol%, preferably in the range of 20 to 99 mol%, and in the range of 30 to 98 mol%. Is more preferable.

  Below, the example of the repeating unit which can form a copolymer with the repeating unit represented by Formula (1) is shown.

  The molecular weight of the polymer is preferably from 1,000 to 1,000,000, more preferably from 1,000 to 500,000, and most preferably from 1,000 to 100,000.

[Polymerization catalyst and ligand]
The polymerization catalyst and the ligand are used in an atom transfer radical polymerization method.
The polymerization catalyst is generally a transition metal complex. The central metal of the transition metal complex is preferably a metal belonging to Group 7, Group 8, Group 9, Group 10, or Group 11 of the Periodic Table. The metal is preferably zero-valent copper, monovalent copper, divalent ruthenium, divalent iron, or divalent nickel, and more preferably copper. Monovalent copper compounds (eg, cuprous chloride, cuprous bromide, cuprous iodide, cuprous cyanide, cuprous oxide, cuprous perchlorate) are particularly preferred.

When a copper compound is used, a ligand is added to increase the catalytic activity. Examples of ligands include 2,2′-bipyridyl and its derivatives, 1,10-phenanthroline and its derivatives, polyamines (eg, tetramethylethylenediamine, pentamethyldiethylenetriamine, hexamethyltris (2-aminoethyl) amine). Including. A tristriphenylphosphine complex of divalent ruthenium chloride (RuCl ₂ (PPh ₃ ) ₃ ) is also a preferred catalyst.
When a ruthenium compound is used as a catalyst, an aluminum alkoxide is added as an activator.
Further, a divalent iron bistriphenylphosphine complex (FeCl ₂ (PPh ₃ ) ₂ ), a divalent nickel bistriphenylphosphine complex (NiCl ₂ (PPh ₃ ) ₂ ), and a divalent nickel bistributylphosphine complex (NiBr ₂ (PBu ₃ ) ₂ ) is also a preferred catalyst.

[Initiator]
When the surface graft polymer is grown using hollow silica into which a functional group having chain transfer ability is introduced, it is necessary to use a separate initiator.
When employing a free radical polymerization method, an azo initiator or a peroxide initiator can be used. Examples of organic peroxides include benzoyl peroxide, halogen benzoyl peroxide, lauroyl peroxide, acetyl peroxide, dibutyl peroxide, cumene hydroperoxide, butyl hydroperoxide. Examples of inorganic peroxides include hydrogen peroxide, ammonium persulfate, and potassium persulfate. Examples of azo compounds are 2,2′-azobisisobutyronitrile, 2,2′-azobispropionitrile, 2,2′-azobisdimethylvaleronitrile, 2,2′-azobiscyclohexanedinitrile. And diazoaminobenzene and p-nitrobenzenediazonium as diazo compounds.

  Also when using the hollow silica which introduce | transduced the functional group which has a polymerization initiating ability, you may use together an initiator separately. Select an initiator suitable for the polymerization method employed. If the atom transfer radical polymerization method is used, an alkyl halide, benzyl halide, α-haloester, α-haloketone, α-halonitrile or sulfonyl halide having the same functional group as that introduced into the hollow silica may be used in combination. preferable. Specific examples are shown in Matyjaszewski, Xia, “Chemical Review” (2001, 101, No. 9, P2921).

[Layer structure of optical film]
The optical film has a hard coat layer, which will be described later, on a transparent base material, if necessary, and the refractive index, film thickness, number of layers, layer order, etc. so that the reflectance is reduced by optical interference on the optical film. It is preferable to laminate in consideration of the above.
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. Examples of configurations include two layers of a high refractive index layer / low refractive index layer from the base material side, and three layers having different refractive indices, a medium refractive index layer (having a higher refractive index than the base material or the hard coat layer). , A layer having a lower refractive index than a high refractive index layer) / a high refractive index layer / a low refractive index layer, and the like. Especially, it is preferable to apply | coat in order of a middle refractive index layer / high refractive index layer / low refractive index layer on the base material which has a hard-coat layer from durability, an optical characteristic, cost, productivity, etc.

An example of a preferable layer structure of the low reflection laminate is shown below.
Base film / low refractive index layer,
Base film / antiglare layer / low refractive index layer,
Base film / hard coat layer / antiglare layer / low refractive index layer,
Base film / hard coat 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 / antiglare layer / high refractive index layer / low refractive index layer,
Base film / antiglare 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,
Base film / antistatic layer / antiglare layer / medium refractive index layer / high refractive index layer / low refractive index layer,
Antistatic layer / base film / antiglare layer / medium refractive index layer / high refractive index layer / low refractive index layer,
Antistatic layer / base film / antiglare layer / high refractive index layer / low 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 high refractive index layer may be a light diffusing layer having no antiglare property. The antistatic layer is preferably a layer containing conductive polymer particles or metal oxide particles (eg, SnO ₂ , ITO), and can be provided by coating or atmospheric pressure plasma treatment.

[Film-forming binder]
It is preferable to use a compound having an ethylenically unsaturated group as the main film-forming binder component of the film-forming composition in terms of film strength, coating solution stability, and coating film productivity. The main film-forming binder refers to a material that occupies 10% by mass or more of the film-forming components excluding inorganic particles. Preferably, they are 20 mass% or more and 100 mass% or less, More preferably, they are 30 mass% or more and 95 mass% or less.

  A polymer having a saturated hydrocarbon chain or a polyether chain as a main chain is preferable, and a polymer having a saturated hydrocarbon chain as a main chain is more preferable. As the binder polymer having a saturated hydrocarbon chain as the main chain and having a crosslinked structure, a 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 (eg, 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 polymer Acrylate), vinylbenzene and its derivatives (eg, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinylsulfone (eg, divinylsulfone), acrylamide (eg, , Methylenebisacrylamide) and methacrylamide. Two or more of these monomers may be used in combination.

  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 carried out by irradiation with ionizing radiation or heating in the presence of a photo radical initiator or a thermal radical initiator.

  As radical photopolymerization initiators, acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds And 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 is included. Examples of benzoins include benzoin benzene sulfonate, benzoin toluene sulfonate, benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether. Examples of the benzophenones include benzophenone, 2,4-dichlorobenzophenone, 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.159, publisher: Kazuhiro Takasato, publisher; Technical Information Association, Inc., published in 1991).

  The commercially available photocleavable photoradical polymerization initiator is preferably Irgacure (651, 184, 907) manufactured by Ciba Geigy Japan.

  It is preferable to use a photoinitiator in the range of 0.1-15 mass parts with respect to 100 mass parts of polyfunctional monomers, More preferably, it is the range of 1-10 mass parts.

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

  As the thermal radical initiator, organic or inorganic peroxides, organic azo, diazo compounds, and the like can be used. Specifically, benzoyl peroxide, halogen benzoyl peroxide, lauroyl peroxide, acetyl peroxide, dibutyl peroxide, cumene hydroperoxide, butyl hydroperoxide as organic peroxides, hydrogen peroxide, peroxides as inorganic peroxides. Ammonium sulfate, potassium persulfate, etc., 2,2′-azobisisobutyronitrile, 2,2′-azobispropionitrile, 2,2′-azobiscyclohexanedinitrile as azo compounds, diazoamino as diazo compounds Examples thereof include benzene and p-nitrobenzenediazonium.

  A polymer having a polyether as a main chain can also be used. Ring opening polymers of polyfunctional epoxy compounds are 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.

  Instead 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 polymer, and by reaction of this crosslinkable functional group, A crosslinked structure may be introduced into the binder polymer.

  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, the crosslinkable functional group may not react immediately but may exhibit reactivity as a result of decomposition.

  These binder polymers having a crosslinkable functional group can form a crosslinked structure by heating after coating.

[Material for low refractive index layer]
The low refractive index layer is formed from a cured film of hollow silica in which a polymer is covalently bonded to the surface. The hollow silica surface-treated with a polymer may be used in combination. Further, in order to form a layer having a lower refractive index, a repeating unit derived from a fluorine-containing vinyl monomer and a repeating unit having a crosslinkable group in the side chain, particularly a (meth) acryloyl group or an epoxy group, are essential constituent components. More preferably, the copolymer is used in combination as a curable resin. The copolymer-derived component preferably accounts for 60% by mass or more, more preferably 70% by mass or more, and particularly preferably 80% by mass or more. From the viewpoint of achieving both low refractive index and film hardness, a curing agent such as polyfunctional (meth) acrylate is also preferably used in an addition amount within a range that does not impair the compatibility.

  The refractive index of the low refractive index layer is preferably 1.20 to 1.46, more preferably 1.25 to 1.46, and particularly preferably 1.30 to 1.46.

  The thickness of the low refractive index layer is preferably 50 to 200 nm, and more preferably 70 to 100 nm. The haze of the low refractive index layer is preferably 3% or less, more preferably 2% or less, and most preferably 1% or less. The specific strength of the low refractive index layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in a pencil hardness test under a 500 g load.

  In order to improve the antifouling performance of the optical film, it is preferable that the contact angle of the surface with respect to water is 90 ° or more. More preferably, it is 95 ° or more, and particularly preferably 100 ° or more.

[Hollow silica]
The average particle diameter of the hollow silica can be appropriately selected. However, when hollow silica is used for the low refractive index layer of the antireflective film, the average particle size of the hollow silica is preferably 30% or more and 150% or less, more preferably 35% or more and 80% or less of the thickness of the low refractive index layer. More preferably, it is 40% or more and 60% or less. That is, if the thickness of the low refractive index layer is 100 nm, the particle size of the hollow silica is preferably 30 nm to 150 nm, more preferably 35 nm to 80 nm, and still more preferably 40 nm to 60 nm. The hollow silica particles have a refractive index of 1.17 to 1.40, more preferably 1.17 to 1.35, and still more preferably 1.17 to 1.30. Here, the refractive index represents the refractive index of the entire particle, and does not represent the refractive index of only the outer shell silica forming the hollow silica. At this time, when the radius of the void in the particle is a and the radius of the particle outer shell is b, the porosity X is calculated by the following formula (I).

Formula ^{(I) X = (4πa 3} /3) / (4πb 3/3) × 100

  The porosity X is preferably 10 to 60%, more preferably 20 to 60%, and most preferably 30 to 60%. If the hollow silica is made to have a lower refractive index and a higher porosity, the thickness of the outer shell becomes thinner and the strength of the particles becomes weaker. Therefore, from the viewpoint of scratch resistance, the low refractive index is less than 1.17. Particles do not hold. The refractive index of these hollow silicas was measured with an Abbe refractometer (manufactured by Atago Co., Ltd.). Moreover, the refractive index of this layer can be reduced by containing a hollow silica in a low refractive index layer.

When hollow silica is used, the refractive index of the layer is preferably 1.20 or more and 1.46 or less, more preferably 1.25 or more and 1.41 or less, and most preferably 1.30 or more and 1.39 or less. It is. Incidentally, the coating amount of the hollow silica is ^preferably from ^{1mg / m 2 ~100mg / m 2} , more preferably ^{5mg / m 2 ~80mg / m 2} , more preferably from ^{10mg / m 2 ~60mg / m 2} .

  Hereinafter, a copolymer that is preferably used in the low refractive index layer in combination with hollow silica having a polymer grafted on its surface will be described.

  Fluorine-containing vinyl monomers include fluoroolefins (eg, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, etc.), (meth) acrylic acid moieties or fully fluorinated alkyl ester derivatives (eg, biscoat 6FM ( (Trade name, manufactured by Osaka Organic Chemical Co., Ltd.) and R-2020 (trade name, manufactured by Daikin), etc.), and fully or partially fluorinated vinyl ethers, etc. are preferable, preferably perfluoroolefins, refractive index, solubility, From the viewpoints of transparency and availability, hexafluoropropylene is particularly preferable. Increasing the composition ratio of these fluorinated vinyl monomers can lower the refractive index but lowers the film strength. It is preferable to introduce the fluorine-containing vinyl monomer so that the fluorine content of the copolymer is 20 to 60% by mass, more preferably 25 to 55% by mass, and particularly preferably 30 to 50% by mass. is there.

  The copolymer preferably has, as an essential component, a repeating unit having a crosslinkable group in the side chain, particularly a (meth) acryloyl group or an epoxy group. Increasing the composition ratio of these crosslinkable group-containing repeating units improves the film strength but increases the refractive index. Generally, the crosslinkable group-containing repeating unit preferably occupies 5 to 90% by mass, more preferably 30 to 70% by mass, although it varies depending on the type of repeating unit derived from the fluorine-containing vinyl monomer. It is particularly preferable to occupy% by mass.

  In the copolymer, in addition to the repeating unit derived from the fluorine-containing vinyl monomer and the repeating unit having a crosslinkable group in the side chain, the adhesion to the substrate, the Tg of the polymer (contributes to the film hardness), the solubility in the solvent, Other vinyl monomers can be appropriately copolymerized from various viewpoints such as transparency, slipperiness, dust resistance and antifouling properties. A plurality of these vinyl monomers may be combined depending on the purpose, and are preferably introduced in the range of 0 to 65 mol% in total in the copolymer, and more preferably in the range of 0 to 40 mol%. Is particularly preferably in the range of 0 to 30 mol%.

  The vinyl monomer unit that can be used in combination is not particularly limited. For example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic esters (methyl acrylate, methyl acrylate, ethyl acrylate, acrylic acid) 2-ethylhexyl, 2-hydroxyethyl acrylate), methacrylic acid esters (methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-hydroxyethyl methacrylate, etc.), styrene derivatives (styrene, p-hydroxymethylstyrene, p -Methoxystyrene, etc.), vinyl ethers (methyl vinyl ether, ethyl vinyl ether, cyclohexyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, etc.), vinyl esters (vinyl acetate) Vinyl propionate, vinyl cinnamate, etc.), unsaturated carboxylic acids (acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, etc.), acrylamides (N, N-dimethylacrylamide, N-tert-butylacrylamide, N -Cyclohexyl acrylamide, etc.), methacrylamides (N, N-dimethylmethacrylamide), acrylonitrile and the like.

  As a preferred form of the copolymer, there may be mentioned the following formula (2).

In formula (2), G represents a crosslinkable group, preferably a (meth) acryloyl group or an epoxy group. L represents a linking group having 1 to 10 carbon atoms, more preferably a linking group having 1 to 6 carbon atoms, and particularly preferably a linking group having 2 to 4 carbon atoms. It may have, may have a ring structure, and may have a hetero atom selected from O, N, and S.
Preferred examples include * — (CH ₂ ) ₂ —O — **, * — (CH ₂ ) ₂ —NH — **, * — (CH ₂ ) ₄ —O — **, * — (CH ₂ ). _{6 -O - **, * - (} CH 2) 2 -O- (CH 2) 2 -O - **, * - CONH- (CH 2) 3 -O - **, * - CH 2 CH (OH ) CH ₂ —O — **, * —CH ₂ CH ₂ OCONH (CH ₂ ) ₃ —O — ** (* represents a connecting site on the polymer main chain side, and ** represents a connecting site on the crosslinkable group side) And the like). m represents 0 or 1;

  In formula (2), A represents a repeating unit derived from an arbitrary vinyl monomer, and is not particularly limited as long as it is a constituent component of a monomer copolymerizable with hexafluoropropylene. Tg (contributes to film hardness), solubility in solvents, transparency, slipperiness, dustproof / antifouling properties, etc., can be selected as appropriate, depending on the purpose, single or multiple vinyl monomers It may be constituted by.

  Preferred examples include methyl vinyl ether, ethyl vinyl ether, t-butyl vinyl ether, cyclohexyl vinyl ether, isopropyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, glycidyl vinyl ether, vinyl ethers such as allyl vinyl ether, vinyl acetate, vinyl propionate, butyric acid. (Meth) such as vinyl esters such as vinyl, methyl (meth) acrylate, ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, glycidyl methacrylate, allyl (meth) acrylate, (meth) acryloyloxypropyltrimethoxysilane Acrylates, styrene, styrene derivatives such as p-hydroxymethylstyrene, crotonic acid, maleic acid, itaconic acid Can be mentioned unsaturated carboxylic acids and derivatives thereof, more preferably ether derivatives, vinyl ester derivatives, particularly preferably a vinyl ether derivative.

  x, y, and z represent mol% of each constituent component, and represent values satisfying 30 ≦ x ≦ 60, 5 ≦ y ≦ 70, and 0 ≦ z ≦ 65. Preferably, 35 ≦ x ≦ 55, 30 ≦ y ≦ 60, and 0 ≦ z ≦ 20, and particularly preferably 40 ≦ x ≦ 55, 40 ≦ y ≦ 55, and 0 ≦ z ≦ 10.

  The copolymer can be synthesized by various polymerization methods such as solution polymerization, precipitation polymerization, suspension polymerization, precipitation polymerization, bulk polymerization, and emulsion polymerization. The polymerization reaction can be performed by a known operation such as a batch system, a semi-continuous system, or a continuous system. The crosslinkable group may be directly introduced into the monomer to be polymerized, or is preferably introduced by performing a polymer reaction using the reactive functional group.

  The polymerization initiation method includes a method using a radical initiator, a method of irradiating light or radiation, and the like. These polymerization methods and polymerization initiation methods are, for example, the revised version of Tsuruta Junji “Polymer Synthesis Method” (published by Nikkan Kogyo Shimbun, 1971), Takatsu Otsu, Masato Kinoshita, “Experimental Methods for Polymer Synthesis” It is described in pp. 47-154 published in 1972.

  Among the above polymerization methods, a solution polymerization method using a radical initiator is particularly preferable. Solvents used in the solution polymerization method include, for example, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, tetrahydrofuran, dioxane, N, N-dimethylformamide, N, N-dimethylacetamide, benzene, toluene, acetonitrile, A single organic solvent such as methylene chloride, chloroform, dichloroethane, methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol, or a mixture of two or more thereof may be used, or a mixed solvent with water may be used.

  The polymerization temperature needs to be set in relation to the molecular weight of the polymer to be produced, the type of initiator, and the like, and can be from 0 ° C. or lower to 100 ° C. or higher, but it is preferable to perform the polymerization in the range of 50 to 100 ° C.

  The reaction pressure can be selected as appropriate, but usually 0.98 to 98 kPa, particularly about 0.98 to 30 kPa is desirable. The reaction time is about 5 to 30 hours.

  As the reprecipitation solvent for the obtained polymer, isopropanol, hexane, methanol and the like are preferable.

  Hollow silica is used for the low refractive index layer of the antireflection film, but other inorganic particles can be used in combination.

  The inorganic oxide particles are at least one selected from the group consisting of silicon, aluminum, zirconium, titanium, zinc, germanium, indium, tin, antimony and cerium from the viewpoint of the colorlessness of the cured film of the resulting curable composition. Elemental oxide particles are preferred.

  Examples of these inorganic particles include particles of silica, alumina, zirconia, titanium oxide, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide (ITO), antimony oxide, cerium oxide, and the like. it can. Of these, particles of silica, alumina, zirconia and antimony oxide are preferred from the viewpoint of high hardness. These can be used alone or in combination of two or more. Furthermore, the inorganic oxide particles are preferably used as an organic solvent dispersion. When used as an organic solvent dispersion, the dispersion medium is preferably an organic solvent from the viewpoint of compatibility with other components and dispersibility.

  As organic solvents, alcohol (eg, methanol, ethanol, isopropanol, butanol, octanol), ketone (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone), ester (eg, ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone) , Propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate), ether (eg, ethylene glycol monomethyl ether, diethylene glycol monobutyl ether), aromatic hydrocarbon (eg, benzene, toluene, xylene), amide (eg, dimethylformamide, (Dimethylacetamide, N-methylpyrrolidone) can be used. Methanol, isopropanol, butanol, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, toluene and xylene are preferred.

  The number average particle diameter of the inorganic particles is preferably 1 nm to 2000 nm, more preferably 3 nm to 200 nm, and particularly preferably 5 nm to 100 nm. When the number average particle diameter exceeds 2000 μm, the transparency when cured is reduced, and the surface state when coated is liable to deteriorate. Various surfactants and amines may be added to improve the dispersibility of the particles.

  Examples of products that are commercially available as silicon oxide particle dispersions (eg, silica particles) include colloidal silica, methanol silica sol, MA-ST-MS, IPA-ST, and IPA-ST manufactured by Nissan Chemical Industries, Ltd. -MS, IPA-ST-L, IPA-ST-ZL, IPA-ST-UP, EG-ST, NPC-ST-30, MEK-ST, MEK-ST-L, MIBK-ST, NBA-ST, XBA -ST, DMAC-ST, ST-UP, ST-OUP, ST-20, ST-40, ST-C, ST-N, ST-O, ST-50, ST-OL, etc. can be mentioned. As powder silica, Aerosil 130, Aerosil 300, Aerosil 380, Aerosil TT600, Aerosil OX50, Silex H31, H32, H51, H52, H121, H122, Asahi Glass Co., Ltd., Nippon Silica Industry, Nippon Aerosil Co., Ltd. Examples include E220A and E220 manufactured by Fuji Electric, SYLYSIA470 manufactured by Fuji Silysia Co., Ltd., SG flake manufactured by Nippon Sheet Glass Co., Ltd., and the like.

  Moreover, as an aqueous dispersion product of alumina, Nissan Chemical Industries, Ltd. alumina sol-100, -200, -520; As an alumina isopropanol dispersion product, Sumitomo Osaka Cement Co., Ltd. AS-150I; AS-150T manufactured by Sumitomo Osaka Cement Co., Ltd .; HXU-110JC manufactured by Sumitomo Osaka Cement Co., Ltd. as a toluene dispersion of zirconia; Nissan Chemical Industries, Ltd. as an aqueous dispersion of zinc antimonate powder ) Celnax; Alumina, Titanium oxide, Tin oxide, Indium oxide, Zinc oxide, etc. Powder and solvent dispersion products are nanotech made by CI Kasei Co., Ltd .; Antimony-doped tin oxide water dispersion sol is Ishihara Sangyo ( SN-100D, manufactured by Mitsubishi Materials Corporation, and ITO The aqueous dispersion, mention may be made of Taki Chemical Co., Ltd. Nidoraru like.

  The oxide particles have a spherical shape, a hollow shape, a porous shape, a rod shape, a plate shape, a fiber shape, or an indefinite shape, preferably a spherical shape or a hollow shape.

The specific surface area of the oxide particles (by the BET specific surface area measurement method using nitrogen) is preferably 10 to 1000 m ² / g, and more preferably 100 to 500 m ² / g. These inorganic oxide particles can be obtained by dispersing powder in a dry state in an organic solvent. For example, a dispersion of particulate oxide particles known in the art as a solvent dispersion sol of the above oxide is directly used. Can be used.

The coating amount of the inorganic particles is preferably ^1mg / ^{m 2 ~100mg} / m 2 in conjunction with hollow silica, and more preferably ^{5mg / m 2 ~80mg / m 2} , more preferably 10mg ^{/ m 2} ~60mg ^/ m 2 It is.

[Dispersion stabilizing additive]
The dispersion or coating composition may contain a β-diketone compound and / or a β-ketoester compound represented by R ⁴ COCH ₂ COR ⁵ in addition to the silane coupling agent and the acid catalyst or chelate compound. Preferably, these act as stability improvers for the dispersion or coating composition. That is, by coordinating to the metal atom in the metal chelate compound (zirconium, titanium and / or aluminum compound), the action of promoting the condensation reaction of organosilane and metal chelate component by these metal chelate compounds is suppressed, It is considered that it acts to improve the storage stability of the resulting composition. ^{R 4} and ^{R 5} in the compounds represented by R ⁴ COCH ₂ COR ⁵ are the same as ^{R 4} and ^{R 5} constituting the metal chelate compound.

Specific examples of the β-diketone compound and / or β-ketoester compound represented by R ⁴ COCH ₂ COR ⁵ include acetylacetone, methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, isopropyl acetoacetate, butyl acetoacetate, acetoacetate. Sec-butyl acetate, t-butyl acetoacetate, 2,4-hexanedione, 2,4-heptanedione, 3,5-heptanedione, 2,4-octanedione, 2,4-nonanedione, 5-methylhexanedione Can be mentioned. Of these, ethyl acetoacetate and acetylacetone are preferred, and acetylacetone is particularly preferred. These β-diketone compounds and / or β-ketoester compounds may be used alone or in combination of two or more. The (c) component β-diketone compound and / or β-ketoester compound is preferably used in an amount of 2 mol or more, more preferably 3 to 20 mol, per 1 mol of the metal chelate compound. If it is less than 2 mol, the storage stability of the resulting composition may be inferior, which is not preferable.

[Distribution method]
In order to prepare the inorganic oxide particles by dispersing them from a powder in a solvent, a dispersant can be used. It is preferable to use a dispersant having an anionic group.

  As the anionic group, a group having an acidic proton such as a carboxyl group, a sulfonic acid group (sulfo), a phosphoric acid group (phosphono), a sulfonamide group, or a salt thereof is effective, and in particular, a carboxyl group, a sulfonic acid group, A phosphoric acid group or a salt thereof is preferable, and a carboxyl group and a phosphoric acid group are particularly preferable. A plurality of anionic groups may be contained for the purpose of further improving dispersibility. The average number is preferably 2 or more, more preferably 5 or more, and particularly preferably 10 or more. Moreover, the anionic group contained in a dispersing agent may contain multiple types in 1 molecule.

  The dispersant may further contain a crosslinking or polymerizable functional group. Crosslinkable or polymerizable functional groups include ethylenically unsaturated groups (eg, (meth) acryloyl groups, allyl groups, styryl groups, vinyloxy groups, etc.) that can undergo addition reactions and polymerization reactions with radical species, cationic polymerizable groups ( Epoxy group, oxatanyl group, vinyloxy group, etc.), polycondensation reactive groups (hydrolyzable silyl group, etc., N-methylol group), etc., and the like, preferably a functional group having an ethylenically unsaturated group.

  A disperser can be used to grind the inorganic oxide particles. Examples of dispersers include sand grinder mills (eg, pinned bead mills), high speed impeller mills, pebble mills, roller mills, attritors and colloid mills. A sand grinder mill and a high-speed impeller mill are particularly preferred. Further, preliminary dispersion processing may be performed. Examples of the disperser used for the preliminary dispersion treatment include a ball mill, a three-roll mill, a kneader, and an extruder.

[Other materials added to the low refractive index layer]
From the viewpoint of improving the antifouling property, it is preferable to reduce the surface free energy of the antireflection film surface. Specifically, it is preferable to use a fluorine-containing compound or a compound having a polysiloxane structure for the low refractive index layer. Examples of the additive having a polysiloxane structure include reactive group-containing polysiloxanes (for example, KF-100T, X-22-169AS, KF-102, X-22-3701IE, X-22-164B, X-22-5002). , X-22-173B, X-22-174D, X-22-167B, X-22-161AS (above trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), AK-5, AK-30, AK-32 (above product) Name, manufactured by Toa Gosei Co., Ltd.), Silaplane FM0725, Silaplane FM0721 (above trade names, manufactured by Chisso Corporation), etc.) are also preferably added. Further, silicone compounds described in Tables 2 and 3 of JP-A-2003-112383 can also be preferably used. These polysiloxanes are preferably added in the range of 0.1 to 10% by mass of the total solid content of the low refractive index layer, particularly preferably 1 to 5% by mass.

  The organic solvent dispersion of hollow silica described above is used as a coating composition, and each layer of the optical film can be formed from this composition. In particular, it is suitable for forming a low refractive index layer of an antireflection film.

  The low refractive index layer is irradiated with ionizing radiation (eg, light irradiation, electron beam irradiation) simultaneously with coating or after coating and drying a coating composition in which a fluorine-containing compound and other optional components optionally contained are dissolved or dispersed. ) Or heating to form a cross-linking reaction or a polymerization reaction.

In particular, when the low refractive index layer is formed by a crosslinking reaction or a polymerization reaction of an ionizing radiation curable compound, the crosslinking reaction or the polymerization reaction is preferably performed in an atmosphere having an oxygen concentration of 10% by volume or less. . By forming in an atmosphere having an oxygen concentration of 10% by volume or less, an outermost layer excellent in physical strength and chemical resistance can be obtained.
The oxygen concentration is preferably 6% by volume or less, more preferably 4% by volume or less, particularly preferably 2% by volume or less, and most preferably 1% by volume or less.

  As a method of reducing the oxygen concentration to 10% by volume or less, it is preferable to replace the atmosphere (nitrogen concentration of about 79% by volume, oxygen concentration of about 21% by volume) with another gas, particularly preferably replacement with nitrogen (nitrogen purge). It is to be.

[Material for high refractive index layer]
It is preferable to provide a high refractive index layer in the antireflection film. The high refractive index layer can be formed from a binder, mat particles for imparting antiglare properties, and an inorganic filler for increasing the refractive index, preventing crosslinking shrinkage, and increasing the strength.

  For the purpose of imparting antiglare properties, the high refractive index layer has a matte particle having an average particle size of 0.1 to 5.0 μm, preferably 1.5 to 3.5 μm, for example, inorganic compound particles. Alternatively, resin particles can be contained. If the refractive index difference between the matte particles and the binder is too large, the film becomes cloudy, and if it is too small, a sufficient light diffusing effect cannot be obtained, so 0.02 to 0.20 is preferable, and 0.04 to Particularly preferred is 0.10. As with the refractive index, the addition amount of the matting particles to the binder is too large, the film becomes cloudy, and if it is too small, a sufficient light diffusion effect cannot be obtained. A percentage is particularly preferred.

As specific examples of the mat particles, inorganic particles such as silica particles and TiO ₂ particles; resin particles such as acrylic particles, crosslinked acrylic particles, polystyrene particles, crosslinked styrene particles, melamine resin particles, and benzoguanamine resin particles are preferable. Can be mentioned. Of these, crosslinked styrene particles, crosslinked acrylic particles, and silica particles are preferred.
The shape of the mat particles can be either a true sphere or an indefinite shape.

  Two or more different kinds of mat particles may be used in combination. When two or more kinds of mat particles are used, the difference in refractive index is preferably 0.02 or more and 0.10 or less in order to effectively exert the refractive index control by mixing the two, and 0.03 or more. Is particularly preferably 0.07 or less. Further, it is possible to impart an antiglare property with mat particles having a larger particle size and to impart another optical characteristic with mat particles having a smaller particle size. For example, when an optical film is attached to a high-definition display of 133 ppi or more, it is required that there is no optical performance defect called glare. Glitter is derived from the fact that the unevenness (contributing to anti-glare properties) present on the film surface causes the pixels to be enlarged or reduced, resulting in loss of brightness uniformity, but with a particle size smaller than the matte particles that impart anti-glare properties. It can be greatly improved by using mat particles having a different refractive index from the binder.

Further, the particle size distribution of the matte particles is most preferably monodispersed, and the particle sizes of the particles are preferably closer to each other. For example, when a particle having a particle size of 20% or more than the average particle size is defined as a coarse particle, the proportion of the coarse particle is preferably 1% or less, more preferably 0.1% of the total number of particles. Or less, more preferably 0.01% or less. The matting particles having such a particle size distribution are obtained by classification after a normal synthesis reaction, and a matting agent having a more preferable distribution can be obtained by increasing the number of classifications or increasing the degree thereof.
The mat particles are contained in the hard coat layer so that the amount of the mat particles in the formed hard coat layer is preferably 10 to 1000 mg / m ² , more preferably 100 to 700 mg / m ² .

  The particle size distribution of the matte particles is measured by a Coulter counter method, and the measured distribution is converted into a particle number distribution.

  The hard coat layer has at least one selected from titanium, zirconium, aluminum, indium, zinc, tin, and antimony, in addition to the above mat particles, in order to increase the refractive index of the layer and to reduce cure shrinkage. It is preferable to contain an inorganic filler made of one kind of metal oxide and having an average particle size of 0.2 μm or less, preferably 0.1 μm or less, more preferably 0.06 μm or less.

  In order to increase the difference in refractive index from the mat particles, it is also preferable to use a silicon oxide in order to keep the refractive index of the hard coat layer using the high refractive index mat particles low. The preferred particle size is the same as that of the aforementioned inorganic filler.

Specific examples of the inorganic filler used in the hard coat layer include TiO ₂ , ZrO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO and SiO ₂ . TiO ₂ and ZrO ₂ are particularly preferable in terms 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 hard coat layer, more preferably 20 to 80%, and particularly preferably 30 to 70%.

  Such a filler does not scatter because the particle size is sufficiently smaller than the wavelength of light, and a dispersion in which the filler is dispersed in a binder polymer behaves as an optically uniform substance.

  The bulk refractive index of the mixture of binder and inorganic filler in the hard coat layer 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 experimentally in advance.

  The formed optical film has a haze value in the range of 3 to 70%, preferably 4 to 60%, and an average reflectance of 450 nm to 650 nm is 3.0% or less, preferably 2.5% or less. .

  When the optical film has a haze value and an average reflectance in the above range, good antiglare properties and antireflection properties can be obtained without causing deterioration of the transmitted image.

[Support]
As the transparent support of the optical film, it is preferable to use a plastic film. Examples of the polymer forming the plastic film include cellulose esters (eg, triacetyl cellulose, diacetyl cellulose, typically TAC-TD80U, TD80UF, etc. manufactured by Fuji Photo Film), polyamide, polycarbonate, polyester (eg, polyethylene terephthalate, polyethylene). Naphthalate), polystyrene, polyolefin, norbornene resin (Arton: trade name, manufactured by JSR), amorphous polyolefin (ZEONEX: trade name, manufactured by Nippon Zeon), and the like. Of these, triacetyl cellulose, polyethylene terephthalate, and polyethylene naphthalate are preferable, and triacetyl cellulose is particularly preferable. In addition, regarding the cellulose acylate film substantially free of halogenated hydrocarbons such as dichloromethane and the process for producing the same, the technical report published by the Society of Invention (Publication No. 2001-1745, published on March 15, 2001, the following published technical report) The cellulose acylate described here can also be preferably used.

[Saponification]
When the optical film is used in a liquid crystal display device, it is disposed on the outermost surface of the display by providing an adhesive layer on one side. When the transparent support is triacetyl cellulose, triacetyl cellulose is used as a protective film for protecting the polarizing layer of the polarizing plate. Therefore, it is preferable in terms of cost to use the optical film as it is for the protective film.

  When an optical film is placed on the outermost surface of a display by providing an adhesive layer on one side or used as it is as a protective film for a polarizing plate, it is necessary to contain a fluorine-containing film on a transparent support in order to sufficiently adhere it. It is preferable to perform a saponification treatment after forming the outermost layer mainly composed of a polymer. The saponification treatment is performed by a known method, for example, by immersing the film in an alkali solution for an appropriate time. After being immersed in the alkali solution, it is preferable to sufficiently wash with water or neutralize the alkali component by immersing in a dilute acid so that the alkali component does not remain in the film.

  By saponification treatment, the surface of the transparent support opposite to the side having the outermost layer is hydrophilized.

The hydrophilized surface is particularly effective for improving the adhesion with a deflection film containing polyvinyl alcohol as a main component. In addition, the hydrophilic surface makes it difficult for dust in the air to adhere to it, making it difficult for dust to enter between the deflection film and the optical film when bonded to the deflection film, and is effective in preventing point defects due to dust. It is.
The saponification treatment is preferably carried out so that the contact angle of water on the surface of the transparent support opposite to the side having the outermost layer is 40 ° or less. More preferably, it is 30 ° or less, particularly preferably 20 ° or less.

Specific means for the alkali saponification treatment can be selected from the following two means (1) and (2). (1) is superior in that it can be processed in the same process as a general-purpose triacetyl cellulose film, but since the saponification treatment is performed up to the antireflection film surface, the surface is degraded by alkali hydrolysis, and the saponification treatment. The point that it becomes dirty when the liquid remains can be a problem. In that case, although it becomes a special process, (2) is excellent.
(1) After the antireflection layer is formed on the transparent support, the back surface of the film is saponified by immersing it in an alkaline solution at least once.
(2) Before or after forming the antireflection layer on the transparent support, the alkaline liquid is applied to the surface of the optical film opposite to the surface on which the optical film is formed, and is heated, washed with water and / or neutralized. Thus, only the back surface of the film is saponified.

[Coating film forming method]
The optical film can be formed by the following method.

  First, a coating solution containing components for forming each layer is prepared. The coating solution is applied onto a transparent support by dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating or extrusion coating (see US Pat. No. 2,681,294). Heat and dry. Among these coating methods, it is preferable to apply the gravure coating method because a coating solution with a small coating amount such as each layer of the antireflection film can be applied with high film thickness uniformity. Among the gravure coating methods, the micro gravure method has a high film thickness uniformity and is more preferable.

  In addition, a coating solution with a small coating amount can be applied with high film thickness uniformity even by using a die coating method. Further, since the die coating method is a pre-measuring method, film thickness control is relatively easy, and the solvent in the coating part Is preferred because of less transpiration. Two or more layers may be applied simultaneously. The method of simultaneous application is described in US Pat. Nos. 2,761,791, 2,941,898, 3,508,947, and 3,526,528 and Yuji Harasaki, Coating Engineering, page 253, Asakura Shoten (1973).

  From the viewpoint of production cost, at least two of the plurality of layers of the antireflection film are formed by the steps of feeding the support film once, forming each optical thin film, and winding the film. Preferably, when the antireflection layer has a three-layer structure, it is more preferable to form the three layers in one step. In such a manufacturing method, a plurality of coating stations and a set of drying and curing zones, preferably the same number or more as the number of optical thin films, are arranged in series between the feeding and winding of the support film of the coating machine. This is achieved by providing.

  In the production of an antireflection film, a medium refractive index layer, a high refractive index layer, a low refractive index layer, 3 layers, a hard coat layer, a high refractive index layer, and a low refractive index layer, a hard coat layer, an antiglare layer As in the case of three low refractive index layers, up to three functional layers can be formed in one step. If necessary, the number of coating stations is reduced to two, and only two layers, the middle refractive index layer and the high refractive index layer, are formed in one step, and the results of checking the surface shape, film thickness, etc. are fed back. To improve the yield, to produce an antiglare antireflection film consisting of two layers, an antiglare layer and a low refractive index layer, at low cost, or as a device configuration increased to four, a hard coat layer, A manufacturing method in which the refractive index layer, the high refractive index layer, and the low refractive index layer are formed in one step to significantly reduce the coating cost can be employed. It is mentioned as another preferable form. In addition, it is desirable from the viewpoint of cost and installation location that the layer is formed only with the UV curable resin and the post-heating zone is omitted.

[Polarizer]
The polarizing plate is mainly composed of two protective films sandwiching a polarizing film from both sides. The optical film is preferably used for at least one of the two protective films sandwiching the polarizing film from both sides. Since the optical film also serves as a protective film, the manufacturing cost of the polarizing plate can be reduced. Further, by using an optical film as the outermost layer, reflection of external light and the like can be prevented, and a polarizing plate having excellent scratch resistance and antifouling properties can be obtained.

  As the polarizing film, a known polarizing film or a polarizing film cut out from a long polarizing film whose absorption axis is neither parallel nor perpendicular to the longitudinal direction may be used. A long polarizing film whose absorption axis is neither parallel nor perpendicular to the longitudinal direction is produced by the following method.

  That is, it is a polarizing film stretched by applying tension while holding both ends of a continuously supplied polymer film by a holding means, and stretched at least 1.1 to 20.0 times in the film width direction. The longitudinal travel speed difference of the holding device is within 3%, and the film travels so that the angle formed by the film traveling direction at the exit of the step of holding both ends of the film and the substantial stretching direction of the film is inclined by 20 to 70 °. The film can be produced by a stretching method in which the direction is bent while holding both ends of the film. In particular, those inclined by 45 ° are preferably used from the viewpoint of productivity.

  The method for stretching the polymer film is described in detail in paragraphs 0020 to 0030 of JP-A-2002-86554.

  When used as one side of the surface protective film of the polarizing film, the optical film is twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), in-plane switching (IPS), optically compensated. It can be preferably used for a transmissive, reflective, or transflective liquid crystal display device in a mode such as a bend cell (OCB).

  The VA mode liquid crystal cell includes (1) a narrowly defined VA mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied, and substantially horizontally when a voltage is applied (Japanese Patent Laid-Open No. Hei 2-). 176625)) (2) Liquid crystal cell (SID97, Digest of tech Papers (Proceedings) 28 (1997) 845) in which VA mode is converted into multi-domain (for MVA mode) in order to enlarge viewing angle (3) A liquid crystal cell in a mode (n-ASM mode) in which rod-like liquid crystalline molecules are substantially vertically aligned when no voltage is applied and twisted multi-domain alignment is applied when a voltage is applied (Preliminary collections 58-59 of the Japan Liquid Crystal Society) 1998)) and (4) SURVAVAL mode liquid crystal cells (presented at LCD International 98).

  For a VA mode liquid crystal cell, a polarizing plate prepared by combining a biaxially stretched triacetyl cellulose film with an optical film is preferably used. As for a method for producing a biaxially stretched triacetylcellulose film, for example, the methods described in JP-A Nos. 2001-249223 and 2003-170492 are preferably used.

  The OCB mode liquid crystal cell is a liquid crystal display device using a bend alignment mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned in a substantially opposite direction (symmetrically) between the upper part and the lower part of the liquid crystal cell. It is disclosed in the specifications of Japanese Patent Nos. 45882525 and 5410422. Since the rod-like liquid crystal molecules are symmetrically aligned at the upper and lower portions of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. For this reason, this liquid crystal mode is also called an OCB (Optically Compensatory Bend) liquid crystal mode. The bend alignment mode liquid crystal display device has an advantage of high response speed.

  In an ECB mode liquid crystal cell, rod-like liquid crystal molecules are substantially horizontally aligned when no voltage is applied, and is most frequently used as a color TFT liquid crystal display device, and is described in many documents. For example, it is described in “EL, PDP, LCD display” published by Toray Research Center (2001).

  In particular, for a TN mode or IPS mode liquid crystal display device, as described in JP-A-2001-100043, an optical compensation film having a viewing angle widening effect is used as a protective film having two polarizing films on both sides. Of these, a polarizing plate having an antireflection effect and a viewing angle widening effect can be obtained with the thickness of one polarizing plate by using it on the surface opposite to the optical film, which is particularly preferable.

[Example 1]
<Introduction of functional group having polymerization initiation ability or chain transfer ability onto hollow silica surface>
(Preparation of dispersion A1)
To 500 parts by mass of hollow silica particle sol (isopropyl alcohol hollow silica sol, CS-60-IPS manufactured by Catalytic Chemical Industry Co., Ltd., average particle diameter 60 nm, shell thickness 10 nm, silica concentration 20 mass%, silica refractive index 1.31) After adding 30 parts by mass of 3- (2-bromopropionyl) propyl) triethoxysilane and 1.5 parts by mass of diisopropoxyaluminum ethyl acetate, 9 parts by mass of ion-exchanged water was added. The mixture was reacted at 60 ° C. for 8 hours and then cooled to room temperature. Subsequently, the surface-treated hollow silica was concentrated in this dispersion with an ultracentrifuge, and the supernatant was discarded and isopropyl alcohol was added for purification. This was repeated three times. It was confirmed by NMR and GC that the residual silane coupling agent was less than 1% by mass, and isopropyl alcohol was added to make the solid content concentration 30% by mass.

(Adjustment of dispersion A2)
To 500 parts by mass of hollow silica particle sol (isopropyl alcohol hollow silica sol, CS-60-IPS manufactured by Catalytic Chemical Industry Co., Ltd., average particle diameter 60 nm, shell thickness 10 nm, silica concentration 20 mass%, silica refractive index 1.31) After adding 30 parts by mass of 3- (2-bromopropionyl) propyl) triethoxysilane and 1.5 parts by mass of diisopropoxyaluminum ethyl acetate, 9 parts by mass of ion-exchanged water was added. The mixture was reacted at 60 ° C. for 8 hours and then cooled to room temperature. The dispersion was then purified by concentrating the surface-treated hollow silica with an ultracentrifuge, discarding the supernatant, and adding cyclohexanone. This was repeated three times. It was confirmed by NMR and GC that the residual silane coupling agent was less than 1% by mass and the residual isopropyl alcohol was less than 0.5% by mass, and cyclohexanone was added to make the solid content concentration 30% by mass.

(Preparation of dispersion B1)
The dispersion A1 was prepared in exactly the same manner except that 3- (2-bromopropionyl) propyl) triethoxysilane was replaced with 3- (2-bromoisobutyroyloxy) propyl) triethoxysilane.

(Preparation of dispersion B2)
The dispersion A2 was prepared in exactly the same manner except that 3- (2-bromopropionyl) propyl) triethoxysilane was changed to 3- (2-bromoisobutyroyloxy) propyl) triethoxysilane.

  Note that 3- (2-bromopropionyl) propyl) dimethylethoxysilane and 3- (2-bromoisobutyroyloxy) propyl) dimethylethoxysilane are described in “J. Am. Chem. Soc. 123, P.7497 (2001). ) "And synthesized.

(Preparation of dispersion C)
To 500 parts by mass of hollow silica particle sol (isopropyl alcohol hollow silica sol, CS-60-IPS manufactured by Catalytic Chemical Industry Co., Ltd., average particle diameter 60 nm, shell thickness 10 nm, silica concentration 20 mass%, silica refractive index 1.31) After adding 30 parts by mass of 3-mercaptopropyltrimethoxysilane and 1.5 parts by mass of diisopropoxyaluminum ethyl acetate, 9 parts by mass of ion-exchanged water was added. The mixture was reacted at 60 ° C. for 8 hours and then cooled to room temperature. The dispersion was then purified by concentrating the surface-treated hollow silica with an ultracentrifuge, discarding the supernatant, and adding cyclohexanone. This was repeated three times. It was confirmed by NMR and GC that the residual silane coupling agent was less than 1% by mass and isopropyl alcohol was less than 0.5% by mass, and cyclohexanone was added to make the solid content concentration 30% by mass.

[Example 2]
<Polymerization from hollow silica surface>
(Preparation of dispersion of surface-modified silica A1-1)
30 parts by mass of dispersion (A1), 1 part by mass of copper (I) bromide, 6 parts by mass of 4,4′-di (5-nonyl) -2,2′-bipyridine, and 50 parts by mass of methyl ethyl ketone in a polymerization vessel After mixing, the polymerization vessel was sealed, cooled, degassed and purged with nitrogen three times, and the inside of the polymerization vessel was brought to a nitrogen atmosphere. Thereafter, 300 parts by mass of 2-hydroxyethyl methacrylate was added, and the mixture was heated to 70 ° C. and polymerized for 8 hours. After completion of the polymerization, the obtained polymerization solution was purified by repeating the reprecipitation operation three times in hexane. The obtained solid content was dissolved in N, N-dimethylacetamide to adjust the solid content concentration to 10% by mass.

(Preparation of dispersion of surface-modified silica A2-1)
30 parts by mass of dispersion (A2), 1 part by mass of copper (I) bromide, 6 parts by mass of 4,4′-di (5-nonyl) -2,2′-bipyridine, and 50 parts by mass of toluene in a polymerization vessel. After mixing, the polymerization vessel was sealed, cooled, degassed and purged with nitrogen three times, and the inside of the polymerization vessel was brought to a nitrogen atmosphere. Thereafter, 300 parts by mass of methyl methacrylate was added, and the mixture was heated to 60 ° C. and polymerized for 8 hours. After completion of the polymerization, the obtained polymerization solution was purified by repeating the reprecipitation operation three times in hexane. The obtained solid content was dissolved in methyl ethyl ketone to adjust the solid content concentration to 20% by mass.

(Preparation of dispersion of surface-modified silica A2-2)
The surface-modified silica (A2-1) was synthesized in the same manner except that methyl methacrylate was changed to ethyl methacrylate.

(Preparation of dispersion of surface-modified silica B1-1)
The surface-modified silica (A1-1) was synthesized in the same manner except that the dispersion (A1) was changed to the dispersion (B1).

(Preparation of dispersion of surface-modified silica B2-1)
The surface-modified silica (A2-1) was synthesized in exactly the same manner except that the dispersion (A2) was changed to the dispersion (B2).

(Preparation of dispersion of surface-modified silica B2-2)
The surface-modified silica (B2-1) was synthesized in the same manner except that methyl methacrylate was changed to ethyl methacrylate.

(Preparation of dispersion of surface-modified silica C-1)
To a solution obtained by mixing 70 parts by mass of dispersion (C), 5 parts by mass of 2,2′-azobis (dimethylvaleronitrile), and 2000 parts by mass of methyl ethyl ketone, 400 parts by mass of U-48 was added dropwise at 65 ° C. After the dropwise addition, polymerization was carried out for 4 hours, and then the polymerization solution was purified by repeating the reprecipitation operation three times in hexane. The obtained solid content was dissolved in acetone to adjust the solid content concentration to 20% by mass.

(Preparation of surface-modified silica C-2 dispersion)
The surface-modified silica (C-1) U-48 was synthesized in exactly the same manner except that it was changed to methyl methacrylate.

(Preparation of dispersion of surface-modified silica C-3)
The surface-modified silica (C-1) U-48 was synthesized in exactly the same manner except that it was changed to ethyl methacrylate.

[Example 3]
<Introduction of crosslinkable group>
(Preparation of dispersion of hollow silica A1-1 ′ having a surface graft polymer having a crosslinkable group in the side chain)
500 parts by mass of surface-modified silica dispersion (A1-1), a polymerization inhibitor (Irganox 1010, manufactured by Ciba Specialty Chemicals) are mixed with 10,000 parts by mass of surface-modified silica, and acrylic acid chloride 70 is mixed there. Part by mass was added dropwise in an ice bath. After completion of the dropwise addition, the reaction was performed at room temperature for 8 hours. Thereafter, the obtained reaction solution was extracted with an ethyl acetate / water system, and the ethyl acetate layer was dried over magnesium sulfate. Furthermore, the reprecipitation operation was repeated 3 times in hexane. The obtained solid content was dissolved in methyl ethyl ketone to adjust the solid content concentration to 20% by mass.

(Preparation of dispersion of hollow silica B1-1 ′ having a surface graft polymer having a crosslinkable group in the side chain)
Except that the surface-modified silica dispersion (A1-1) of the hollow silica (A1-1 ′) having a surface graft polymer having a crosslinkable group in the side chain is changed to the surface-modified silica dispersion (B1-1). Synthesized in the same manner.

(Preparation of dispersion of hollow silica C-1 ′ having a surface graft polymer having a crosslinkable group in the side chain)
500 parts by mass of surface-modified silica dispersion (C-1) and Irganox 1010 (manufactured by Ciba Specialty Chemicals) were mixed with 10,000 parts by mass of surface-modified silica, and 50 parts by mass of triethylamine was added dropwise in an ice bath. did. After completion of the dropwise addition, the reaction was performed at room temperature for 8 hours. Thereafter, the obtained reaction solution was extracted with an ethyl acetate / water system, and the ethyl acetate layer was dried over magnesium sulfate. Furthermore, the reprecipitation operation was repeated 3 times in hexane. The obtained solid content was dissolved in methyl ethyl ketone to adjust the solid content concentration to 20% by mass.

(Preparation of comparative dispersion D-1)
Hollow silica particle sol (Isopropyl alcohol hollow silica sol, CS-60-IPS manufactured by Catalytic Chemical Industry Co., Ltd., average particle diameter 60 nm, shell thickness 10 nm, silica concentration 20 mass%, silica refractive index 1.31) After adding 1.5 parts by mass of isopropoxyaluminum ethyl acetate and mixing, 9 parts by mass of ion-exchanged water was added. The mixture was reacted at 60 ° C. for 8 hours and then cooled to room temperature.

(Preparation of comparative dispersion D-2)
Hollow silica particle sol (isopropyl alcohol hollow silica sol, CS-60-IPS manufactured by Catalytic Chemical Industry Co., Ltd., average particle diameter 60 nm, shell thickness 10 nm, silica concentration 20 mass%, silica refractive index 1.31) 500 parts by mass After performing the same treatment as -1, the solvent was replaced by vacuum distillation at a pressure of 39 hPa while adding methyl ethyl ketone so that the silica content was almost constant. The residual amount of isopropyl alcohol in the obtained dispersion was analyzed by gas chromatography and found to be 0.5% by mass or less.

[Example 4]
For the dispersions obtained in Example 2 and Example 3, the following evaluation was performed immediately after preparation and after storage at 25 ° C. for 2 weeks.

Evaluation 1: Evaluation of foreign matter in dispersion 10 cc of the dispersion was collected in a test tube having a diameter of 10 mm, and the foreign matter was visually observed. The degree of occurrence of foreign matters that can be visually observed was evaluated in the following four ranks.
A: Foreign matter is not recognized.
B: Foreign matter of about 50 μm is slightly observed.
C: Foreign matter of 500 μm or more is clearly observed.
D: In addition to foreign matters of 500 μm or more, agglomerated precipitates are clearly observed.

Table 1 ────────────────────────────────────────
Dispersion No. Generation of foreign matter immediately after production Generation of foreign matter after 2 weeks at 25 ℃ ─────────────────────────────── ────────
A2-1 A A
A2-2 A A
B2-1 A A
B2-2 A A
C-2 A A
C-3 A A
A1-1 'A A
B1-1 'A A
C1-1 'A A
D-1 C D
D-2 D D
───────────────────────────────────────

  From the results shown in Table 1, it can be seen that the hollow silica particle dispersion in which the polymer is covalently bonded to the surface according to the present invention is high in temperature and treated with a small amount of foreign matter and is excellent in dispersion stability. .

[Example 5]
(Preparation of coating solution for hard coat layer)
750.0 parts by mass of trimethylolpropane triacrylate (Biscoat # 295, manufactured by Nippon Kayaku Co., Ltd.), 270.0 parts by mass of poly (glycidyl methacrylate) having a mass average molecular weight of 15000, 730.0 parts by mass of methyl ethyl ketone, 500. 0 parts by mass and 50.0 parts by mass of a photopolymerization initiator (Irgacure 184, manufactured by Nippon Ciba Geigy Co., Ltd.) were put into a mixing tank and stirred. The solution was filtered through a polypropylene filter having a pore size of 0.4 μm to prepare a coating solution for a hard coat layer.

(Preparation of titanium dioxide fine particle dispersion)
Titanium dioxide fine particles (MPT-129C, manufactured by Ishihara Sangyo Co., Ltd., TiO ₂ : Co ₃ O ₄ : Al) containing cobalt and surface-treated with aluminum hydroxide and zirconium hydroxide as titanium dioxide fine particles ₂ O ₃ : ZrO ₂ = 90.5: 3.0: 4.0: 0.5 mass ratio) was used.
The following dispersant (41.1 parts by mass) and cyclohexanone (701.8 parts by mass) were added to 257.1 parts by mass of the particles and dispersed by dynomill to prepare a titanium dioxide dispersion having a mass average diameter of 70 nm.

(Preparation of coating solution for medium refractive index layer)
In 99.1 parts by mass of the above titanium dioxide dispersion, 68.0 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA), 3.6 parts by mass of a photopolymerization initiator (Irgacure 907), light A sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1.2 parts by mass, methyl ethyl ketone 279.6 parts by mass and cyclohexanone 1049.0 parts by mass were added and stirred. After sufficiently stirring, the solution was filtered through a polypropylene filter having a pore diameter of 0.4 μm to prepare a coating solution for a medium refractive index layer.

(Preparation of coating solution for high refractive index layer)
To 469.8 parts by mass of the above titanium dioxide dispersion, 40.0 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, Nippon Kayaku Co., Ltd.), a photopolymerization initiator (Irgacure 907) 3.3 parts by mass, manufactured by Ciba Geigy Co., Ltd.), 1.1 parts by mass of photosensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.), 526.2 parts by mass of methyl ethyl ketone, and 459.6 parts by mass of cyclohexanone. Was added and stirred. The solution was filtered through a polypropylene filter having a pore diameter of 0.4 μm to prepare a coating solution for a high refractive index layer.

Into a stainless steel autoclave with a stirrer of 100 ml, 40 ml of ethyl acetate, 14.7 g of hydroxyethyl vinyl ether and 0.55 g of dilauroyl peroxide were charged, and the inside of the system was deaerated and replaced with nitrogen gas. Further, 25 g of hexafluoropropylene (HFP) was introduced into the autoclave and the temperature was raised to 65 ° C. The pressure when the temperature in the autoclave reached 65 ° C. was 5.4 kg / cm ² . The reaction was continued for 8 hours while maintaining the temperature, and when the pressure reached 3.2 kg / cm ² , the heating was stopped and the mixture was allowed to cool. When the internal temperature dropped to room temperature, unreacted monomers were driven out, the autoclave was opened, and the reaction solution was taken out. The obtained reaction solution was poured into a large excess of hexane, and the polymer was precipitated by removing the solvent by decantation. Further, this polymer was dissolved in a small amount of ethyl acetate and reprecipitated twice from hexane to completely remove the residual monomer. After drying, 28 g of polymer was obtained. Next, 20 g of the polymer was dissolved in 100 ml of N, N-dimethylacetamide, and 11.4 g of acrylic acid chloride was added dropwise under ice cooling, followed by stirring at room temperature for 10 hours. Ethyl acetate was added to the reaction solution, washed with water, the organic layer was extracted and concentrated, and the resulting polymer was reprecipitated with hexane to obtain 19 g of a fluoropolymer (1).

(Preparation of coating solution a for low refractive index layer)
2-butanone 200 parts by mass, cyclohexanone 150 parts by mass, fluorine-containing polymer (1) 75.2 parts by mass, methacrylate group-containing silicone resin RMS-033 (manufactured by Gelest Co., Ltd.) 3 parts by mass, photoradical generator 3 parts by mass of Irgacure 907 (trade name) and 18.8 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, Nippon Kayaku Co., Ltd.) were added and dissolved. A low refractive index layer coating solution a was prepared by diluting with methyl ethyl ketone so that the solid content concentration of the entire coating solution was 7% by mass.

(Preparation of antireflection film 301)
A hard coat layer coating solution was applied on a triacetyl cellulose film (TD80UF, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm using a gravure coater. After drying at 100 ° C., an irradiance of 400 mW / cm using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 160 W / cm while purging with nitrogen so that the oxygen concentration becomes 1.0 vol% or less. ^{2. The} coating layer was cured by irradiating ultraviolet rays with an irradiation amount of 300 mJ / cm ² to form a hard coat layer having a thickness of 8 μm.
On the hard coat layer, an intermediate refractive index layer coating solution, a high refractive index layer coating solution, and a low refractive index layer coating solution a were successively applied using a gravure coater having three coating stations.

The medium refractive index layer was dried at 90 ° C. for 30 seconds, and the ultraviolet curing condition was 180 W / cm air-cooled metal halide lamp (eye graphics) while purging with nitrogen so that the atmosphere had an oxygen concentration of 1.0% by volume or less. The irradiance was 400 mW / cm ² and the irradiation amount was 400 mJ / cm ² .
The medium refractive index layer after curing had a refractive index of 1.630 and a film thickness of 67 nm.

The high refractive index layer was dried at 90 ° C. for 30 seconds, and the ultraviolet curing condition was 240 W / cm ² air-cooled metal halide lamp (eye graphics) while purging with nitrogen so that the atmosphere had an oxygen concentration of 1.0% by volume or less. The irradiance was 600 mW / cm ² and the irradiation amount was 400 mJ / cm ² . The cured high refractive index layer had a refractive index of 1.905 and a film thickness of 107 nm.

The low refractive index layer was dried at 90 ° C. for 30 seconds, and the ultraviolet curing condition was 240 W / cm ² air-cooled metal halide lamp (eye graphics) while purging with nitrogen so that the atmosphere had an oxygen concentration of 0.05 vol% or less. The irradiance was 600 mW / cm ² and the irradiation amount was 600 mJ / cm ² .
The low refractive index layer after curing had a refractive index of 1.458 and a film thickness of 85 nm.

(Preparation of antireflection film 302)
A sample 302 was prepared by changing the low refractive index layer coating solution from the sample 301 to the following low refractive index layer coating solution b. Samples 301 and 302 have the same meaning as antireflection films 301 and 302. The same applies hereinafter.

(Preparation of sol solution I)
A stirrer, a reactor equipped with a reflux condenser, 120 parts by mass of methyl ethyl ketone, 100 parts by mass of acryloyloxypropyltrimethoxysilane (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.), 3 parts by mass of diisopropoxyaluminum ethyl acetoacetate After addition and mixing, 30 parts by mass of ion-exchanged water was added and reacted at 60 ° C. for 4 hours, and then cooled to room temperature to obtain sol solution I. The mass average molecular weight was 1600, and among the components higher than the oligomer component, the component having a molecular weight of 1000 to 20000 was 100% by mass. Further, from the gas chromatography analysis, the raw material acryloyloxypropyltrimethoxysilane did not remain at all.

(Adjustment of coating solution b for low refractive index layer)
With respect to 200 parts by mass of methyl ethyl ketone and 150 parts by mass of cyclohexanone, 30 parts by mass of the fluorine-containing polymer used in the coating solution A for low refractive index layer, 3 parts by mass of methacrylate group-containing silicone resin RMS-033 (manufactured by Gelest Co., Ltd.), After adding 3 parts by mass of photoradical generator Irgacure 907 (trade name) and 7 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, Nippon Kayaku Co., Ltd.), the sol 45 parts by mass of liquid I (27 parts by mass as a solid content after solvent volatilization) and 150 parts by mass of dispersion D-2 prepared in Example 2 (20 parts by mass as a silica solid content) were added. The coating liquid b for low refractive index layer was completed by diluting with methyl ethyl ketone so that the solid content concentration of the entire coating liquid was 7% by mass.

  The low refractive index layer coating solution b thus obtained was applied according to Sample 301, and the low refractive index layer thickness was adjusted to 85 nm to prepare Sample 302. The refractive index of the low refractive index layer of Sample 302 was 1.435.

(Evaluation of antireflection film)
The obtained film was evaluated for the following items.
(1) Plane shape of coating film sample Oily black ink was applied to the back surface of the coated sample, and the angle was changed at about 10 cm under a 500 W three-wavelength fluorescent lamp, and visually evaluated.
The unevenness in which reflected light is diffused and appears white and dull is evaluated according to the following criteria.
A: Even if you look very carefully, you can't see any haze.
B: Light is diffused slightly when viewed very carefully.
C: A white portion is observed in a haze.
D: One surface has a white haze.

(2) Steel Wool Scratch Resistance (SW Strength) Evaluation Using a rubbing tester, a rubbing test was performed under the following conditions.
Evaluation environmental conditions: 25 ° C., 60% RH
Rubbing material: Steel wool (No. 0000, manufactured by Nippon Steel Wool Co., Ltd.) was wound around the rubbing tip (1 cm × 1 cm) of a tester in contact with the sample, and the band was fixed so as not to move.
Moving distance (one way): 13 cm, rubbing speed: 13 cm / sec, load: 500 g / cm ² ,
Tip contact area: 1 cm × 1 cm, rubbing frequency: 10 reciprocations.

An oil-based black ink was applied to the back side of the rubbed sample and visually observed with reflected light, and scratches on the rubbed portion were evaluated according to the following criteria.
A: Even if you look very carefully, no scratches are visible.
B: Slightly weak scratches are visible when viewed very carefully, but there is no practical problem.
C: Weak scratches are visible.
D: A moderate crack is visible.
E: There is a scratch that can be seen at first glance.
F: The single-sided film is damaged.

(Preparation of antireflection films 303 to 305)
Samples 303 to 305 were prepared in the same manner except that the dispersion liquid D-2 of the coating liquid b for low refractive index layer used for preparation of the sample 302 was changed to the dispersion liquid described in Table 2. The refractive indexes of Samples 303 to 305 were all around 1.435.

Table 2 ─────────────────────────────────────────
Anti-reflective coating Dispersion Surface shape SW strength
────────────────────────────────────────
301 None AF
302 D-2 C E
303 A1-1 ′ A B
304 B1-1 ′ A A
305 C-1 'A A
────────────────────────────────────────

  The antireflection film prepared as a dispersion of hollow silica covalently bonded with a polymer having a crosslinkable group in the side chain according to the present invention exhibits good values for both the coating surface and SW strength.

[Example 6]
In Example 5, a sample was prepared by changing the polymerizable group of the fluorine-containing polymer of the low refractive index layer coating solutions A and B from acrylate to methacrylate, and the evaluation according to Example 3 was performed. A similar effect was obtained except that the scratch resistance deteriorated.

[Example 7]
80 μm-thick triacetylcellulose film (TD80U, manufactured by Fuji Photo Film Co., Ltd.) that was neutralized and washed with an aqueous solution of NaOH of 1.5 mol / L and 55 ° C. for 2 minutes, and the sample of Example 5 A polarizing plate was prepared by adhering iodine to polyvinyl alcohol on the backside saponified triacetylcellulose film and bonding and protecting both sides of the polarizer. A liquid crystal display device of a notebook personal computer equipped with a transmissive TN liquid crystal display device (Sumitomo 3M Co., Ltd., which is a polarization separation film having a polarization selection layer) so that the anti-reflection film side is the outermost surface. When the D-BEF made by the manufacturing method was replaced with the polarizing plate on the viewing side (having between the backlight and the liquid crystal cell), there was very little reflection of the background, and a display device with very high display quality was obtained.

Claims (16)

  A hollow silica particle dispersion in which hollow silica particles are dispersed in an organic solvent, wherein a polymer having a hydrocarbon main chain is covalently bonded to silica on the surface of the hollow silica particles. Dispersion.   The dispersion of hollow silica particles according to claim 1, wherein the silica on the surface of the hollow silica particles and the polymer having a hydrocarbon main chain are directly covalently bonded.   A binder is interposed between the silica on the surface of the hollow silica particles and the polymer having a hydrocarbon main chain, wherein the silica and the binder are covalently bonded, and the binder and the polymer are covalently bonded. The hollow silica particle dispersion according to 1.   The hollow silica particle dispersion according to claim 1, wherein the polymer having a hydrocarbon main chain has a crosslinkable group. The hollow silica particle dispersion according to claim 4, wherein the polymer having a hydrocarbon main chain includes a repeating unit represented by the following formula (1):

[Wherein R ¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Y is a single bond or a divalent linking group; and G is a crosslinkable group].   The hollow silica particle dispersion according to claim 5, wherein G in formula (1) is an acryloyloxy group, a methacryloyloxy group or an epoxy group.   The hollow silica particle dispersion according to claim 1, further comprising a curable resin.   The hollow silica particle dispersion according to claim 7, wherein the curable resin comprises a polymer or monomer having an ethylenically unsaturated group or an epoxy group.   A hollow silica particle in which a polymer having a hydrocarbon main chain is covalently bonded to a surface silica by polymerizing an ethylenically unsaturated polymerizable compound from the surface silica of the hollow silica particle A method for producing silica particles.   The method for producing hollow silica particles according to claim 9, wherein the polymer having a hydrocarbon main chain covalently bonded to the surface silica is further subjected to a reaction for introducing a crosslinkable group.   The method for producing hollow silica particles according to claim 9, wherein the ethylenically unsaturated polymerizable compound is graft-polymerized from a functional group having a polymerization initiating ability covalently bonded to silica on the surface of the hollow silica particles.   The method for producing hollow silica particles according to claim 9, wherein the ethylenically unsaturated polymerizable compound is graft-polymerized from a functional group having chain transfer ability covalently bonded to silica on the surface of the hollow silica particles.   An optical film having a transparent support and a cured coating comprising hollow silica particles, wherein the cured coating comprising hollow silica particles is dispersed in an organic solvent and carbonized on the surface of the hollow silica particles. An optical film characterized in that it is a film obtained by curing a hollow silica particle dispersion containing a curable resin, wherein a polymer having a hydrogen main chain is covalently bonded.   An antireflection film having a transparent support and a low refractive index layer, wherein the low refractive index layer has hollow silica particles dispersed in an organic solvent, and has a hydrocarbon main chain in the silica on the surface of the hollow silica particles An antireflective film comprising a coating obtained by curing a hollow silica particle dispersion containing a curable resin and having a covalently bonded polymer.   A polarizing plate comprising a polarizing film and two protective films disposed on both sides of the polarizing film, wherein at least one of the protective films has silica particles dispersed on the surface of the hollow silica particles. A polarizing plate, wherein a polymer having a hydrocarbon main chain is covalently bonded, and a coating obtained by curing a hollow silica particle dispersion containing a curable resin.   A display device in which a coating is provided on the outermost surface of the display, wherein the coating has hollow silica particles dispersed in an organic solvent, and the polymer having a hydrocarbon main chain is shared by the silica on the surface of the hollow silica particles. A display device characterized by being a coating obtained by curing a hollow silica particle dispersion that is bonded and further contains a curable resin.