JP2008081728A - Composite fine particles, method for producing the same, and coating composition containing the composite fine particles and optical film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide composite fine particles excellent in curability and having adequate adhesivity and dispersion stability in combination, and a simple method for producing such a composite fine particle. <P>SOLUTION: The composite fine particles comprise inorganic core particles and an organic polymer bonded to at least a part of the surface of the core particles. The organic polymer has an ethylenically unsaturated group in its side chain. The ethylenically unsaturated group is bound to the main chain of the organic polymer through a urethane bond. The organic polymer is preferably an acrylic polymer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to composite fine particles and a method for producing the same. More specifically, the present invention relates to composite fine particles having excellent curability and capable of achieving both adhesion and dispersion stability and a simple production method thereof.

  In recent years, a material that is excellent in wear resistance and curability and gives a transparent cured film has been demanded as a coating material. In order to meet such a demand, many materials have been proposed in which reactive fine particles obtained by modifying the surface of various inorganic fine particles (for example, silica fine particles such as colloidal silica) with a polymerizable functional group have been proposed.

  For example, Patent Document 1 discloses the use of a composition containing acrylate and particles obtained by modifying the surface of colloidal silica with methacryloxysilane as a photocurable coating material. Patent Documents 2 and 3 disclose a method for producing reactive silica by reacting silica fine particles with an organic silane compound having a polymerizable unsaturated group.

However, in any of the above techniques, the amount of polymerizable functional groups that can be introduced onto the surface of the fine particles is insufficient, and as a result, the wear resistance and curability of the resulting reactive fine particles are insufficient. Furthermore, any of the reactive fine particles obtained by the conventional technique has insufficient dispersion stability.
Japanese Patent Publication No.62-21815 Japanese Patent Laid-Open No. 9-100111 Japanese Patent Laid-Open No. 2004-267553

  The present invention has been made to solve the above-described conventional problems, and the object of the present invention is to have composite fine particles having excellent curability and having both adhesion and dispersion stability, and the same The object is to provide a simple production method.

  The composite fine particle of the present invention has an inorganic core particle and an organic polymer bonded to at least a part of the surface of the core particle, and the organic polymer has a polymerizable functional group in its side chain.

  In a preferred embodiment, the polymerizable functional group is bonded to the organic polymer main chain via a urethane bond. In a preferred embodiment, the polymerizable functional group is an ethylenically unsaturated group. In a preferred embodiment, the organic polymer is an acrylic polymer.

  According to another aspect of the present invention, a method for producing composite fine particles is provided. This production method comprises a step of reacting a silicon-containing polymer having a functional group having active hydrogen and a polysiloxane group in the side chain with an isocyanate compound having a polymerizable functional group; the reaction product and a metal by hydrolysis. Reacting with a metal compound capable of forming an oxide.

  In a preferred embodiment, the polymerizable functional group is an ethylenically unsaturated group. In a preferred embodiment, the silicon-containing polymer is an acrylic polymer.

  According to yet another aspect of the invention, a coating composition is provided. This coating composition contains the composite fine particles and a polyfunctional polymerizable compound. Alternatively, a low refractive index coating composition is provided. This low refractive index coating composition contains the composite fine particles and a polyfunctional polymerizable compound, and the organic polymer in the composite fine particles has a portion containing a fluorine atom. In preferred embodiments, these coating compositions further comprise a polymerization initiator and a solvent.

  According to still another aspect of the present invention, an optical film is provided. This optical film includes a coating layer of the coating composition. In one embodiment, an antireflective film is provided. This antireflection film includes a coating layer of the low refractive index coating composition. In another embodiment, a polarizing plate is provided. The polarizing plate includes a polarizer and the antireflection film. In yet another embodiment, an optical filter for a plasma display is provided. The optical filter includes a support and the antireflection film.

  According to still another aspect of the present invention, an image display device is provided. The image display device includes at least one selected from the antireflection film, the polarizing plate, and the optical filter.

  According to the present invention, by introducing a polymerizable functional group (preferably, an ethylenically unsaturated group) into the side chain of the organic polymer bonded to the surface of the core particle, the amount of functional group introduced into the composite fine particles can be reduced compared to the conventional amount. Can be greatly increased. Furthermore, functional groups and organic polymer main chains are bonded via specific bonds (typically urethane bonds), ensuring solubility and dispersibility in solvents mainly due to the organic polymer main chains. In addition, adhesion is largely improved mainly due to the specific bond. Therefore, composite fine particles having excellent curability (hardness, wear resistance, scratch resistance) and having both adhesion and dispersion stability can be obtained.

  The composite fine particle of the present invention has inorganic core particles and an organic polymer bonded to at least a part of the surface of the core particles. In the present specification, “bonding between the core particle and the organic polymer” means that a chemical bond is formed between the organic polymer and the core particle, not physical adhesion. The chemical bond is generated means that, for example, when the composite fine particles are washed with a solvent, the organic polymer is not substantially detected in the washing solution. The organic polymer has a polymerizable functional group in its side chain. In other words, the polymerizable functional group is not directly bonded to the surface of the core particle, but an organic polymer is interposed between the polymerizable functional group and the core particle. Preferably, the polymerizable functional group is an ethylenically unsaturated group. This is because the production is easy and the curability of the particles is excellent.

A. Inorganic Core Particle The inorganic core particle is a particle composed of any appropriate inorganic substance (for example, a simple metal, an inorganic oxide, an inorganic carbonate, an inorganic sulfate, or an inorganic phosphate). The inorganic substance is preferably an inorganic oxide. In the present specification, the “inorganic oxide” refers to various oxygen-containing metal compounds in which a metal element mainly forms a three-dimensional network through bonds with oxygen atoms. As the metal element constituting the inorganic oxide, for example, an element selected from Group II to VI of the Periodic Table of Elements is preferable, and an element selected from Group III to V is more preferable. Among these, an element selected from Si, Al, Ti, and Zr is particularly preferable. Most preferred is silica in which the metal element is Si. It is easy to manufacture and easy to obtain. The core particle may be composed of one kind of inorganic oxide or may be composed of two or more kinds of inorganic oxides. In this specification, for the sake of convenience, metals and semimetals may be collectively referred to as metals.

  The core particle has any suitable shape (for example, spherical shape, needle shape, plate shape, scale shape, and crushed particle shape). The average particle diameter of the core particles is preferably 5 to 200 nm, more preferably 5 to 100 nm, and most preferably 5 to 50 nm. When the average particle diameter of the core particles is less than 5 nm, the surface energy of the composite fine particles becomes high, and the composite fine particles tend to aggregate. If the average particle diameter of the core particles exceeds 200 nm, the transparency of the resulting coating may be reduced.

  The variation coefficient (particle size distribution) of the particle diameter of the core particles is preferably 50% or less, more preferably 40% or less, and most preferably 30% or less. If the coefficient of variation exceeds 50% (if the particle size distribution of the core particles is too large), the resulting coating film surface becomes uneven and the smoothness of the coating film may be lost.

B. Organic polymer The organic polymer is bonded to at least a part of the surface of the core particle. An organic polymer is bonded to the surface of the core particle, and an organic functional group (preferably, an ethylenically unsaturated group) is introduced into the polymer side chain (that is, organic between the polymerizable functional group and the core particle). By interposing a polymer), a much larger amount of functional groups can be introduced into the composite fine particles than in the past. As a result, a coating film having very excellent hardness can be obtained. In the present invention, a part of the organic polymer may be encapsulated in the core particles. In this case, moderate flexibility and toughness can be imparted to the core particles. The presence / absence of the organic polymer in the core particle is determined by, for example, measuring the specific surface area of the core particle after the composite fine particles are heated at 500 to 700 ° C. to thermally decompose the organic polymer, and the theoretical value of the specific surface area of the core particle ( It can be confirmed by comparing with (calculated from the diameter of the core particle measured by TEM or the like). Specifically, when the organic polymer is encapsulated in the core particle, a large number of pores are generated in the core particle due to the thermal decomposition of the organic polymer, so the specific surface area of the core particle after the thermal decomposition is lower than the theoretical value. Is also quite large.

  The organic polymer can have any suitable structure (eg, linear, branched, cross-linked structure). Specific examples of organic polymers include acrylic polymers, styrene polymers, olefin polymers (eg, polyethylene, polypropylene), polyesters (eg, polyethylene terephthalate), vinyl polymers (polyvinyl acetate, polyvinyl chloride), polychlorinated polymers. Examples include vinylidene and copolymers thereof. You may use the polymer which modified these partially by functional groups, such as an amino group, an epoxy group, a hydroxyl group, and a carboxyl group. Acrylic polymers are preferred. The acrylic polymer has an appropriate coating film forming ability and is suitable for use in a film forming composition such as a paint. Examples of the acrylic unit (repeating unit) in the acrylic polymer include a methyl (meth) acrylate unit and an ethyl (meth) acrylate unit. According to the acrylic polymer having such a repeating unit, the stain resistance of the coating can be improved.

  The molecular weight (number average molecular weight) of the organic polymer is preferably 200,000 or less, more preferably 50,000 or less, and most preferably 3,000 to 30,000. If the molecular weight is in such a range, a large amount of functional groups can be introduced into the side chain at appropriate intervals, so that composite fine particles having extremely excellent curability can be obtained, and the dispersion of the composite fine particles can be obtained. Stability can be maintained well.

  The organic polymer has a polymerizable functional group in its side chain. In other words, the polymerizable functional group is not directly bonded to the surface of the core particle, but an organic polymer is interposed between the polymerizable functional group and the core particle. By adopting such a structure, it is possible to obtain composite fine particles having extremely excellent curability and capable of achieving both adhesion and dispersion stability. Preferably, the polymerizable functional group is an ethylenically unsaturated group. Specific examples of the ethylenically unsaturated group include a terminal vinyl group, an allyl group, a (meth) acryl group, an α-substituted methacryl group, an ethylene group, and an acetylene group. These ethylenically unsaturated groups may be introduced singly into the organic polymer side chain, or may be introduced in combination of two or more.

  The polymerizable functional group may be directly bonded to the organic polymer, or may be bonded through any appropriate bond. Preferably, the polymerizable functional group is bonded to the organic polymer main chain via a urethane bond. In this case, the polymerizable functional group can be introduced with very high reaction efficiency without causing gelation or the like.

  The content of the polymerizable functional group in the composite fine particles is preferably 0.1 to 5 mmol / g, more preferably 0.7 to 3 mmol / g, per 1 g of the composite fine particles. With such a content, composite fine particles having an excellent balance between curability and dispersion stability can be obtained.

C. In one embodiment, the method for producing composite fine particles of the present invention comprises a silicon-containing polymer having a functional group having active hydrogen and a polysiloxane group in the side chain, and a polymerizable functional group (preferably, Reacting with an isocyanate compound having an ethylenically unsaturated group); reacting the reaction product with a metal compound capable of producing a metal oxide by hydrolysis (Method 1). In another embodiment, a step of reacting a silicon-containing polymer having a functional group having active hydrogen and a polysiloxane group in a side chain with a metal compound capable of generating a metal oxide by hydrolysis; and a reaction product thereof And a step of reacting an isocyanate compound having a polymerizable functional group (preferably an ethylenically unsaturated group) (Method 2). Method 1 is preferred. This is because the reaction efficiency is high and the polymerizable functional group can be efficiently introduced into the side chain of the organic polymer on the surface of the composite fine particles. Hereinafter, for the sake of simplicity, Method 1 will be mainly described.

  The main chain of the silicon-containing polymer is mainly composed of carbon, and carbon atoms participating in the main chain bond occupy 50 to 100 mol% of the main chain, and the balance is N, O, S, Si, P, or the like. Those composed of elements are preferred for reasons such as availability. The structure and specific examples of the main chain of the silicon-containing polymer are as described for the organic polymer in the above section B. The organic polymer described in the above item B is derived from the main chain of the silicon-containing polymer.

  Representative examples of the functional group having active hydrogen include a hydroxyl group, a carboxyl group, an amino group, and a mercapto group. Hydroxyl groups are preferred. This is because the introduction of the silicon-containing polymer into the side chain is easy and the reactivity with the isocyanate compound is excellent. The functional group may be directly bonded to the main chain of the silicon-containing polymer, or may be bonded via any appropriate group (for example, a methylene group).

  Content of the said functional group in a silicon-containing polymer becomes like this. Preferably it is 10-80 mol%, More preferably, it is 30-60 mol%. Within such a range, composite fine particles having a polymerizable functional group with a desired content can be obtained.

In the present specification, the “polysiloxane group” refers to a group containing a number of siloxane bonds that can form core particles capable of obtaining the effects of the present invention. Therefore, the “polysiloxane group” is not only a group in which two or more Si atoms are connected in a linear or branched manner by a polysiloxane bond (Si—O—Si—O bond), but also a polyfunctional siloxane. It also includes a group containing one Si atom constituting a bond (for example, (linking chain) -R-Si- (OR) ₃ : R is any suitable substituent). Preferably, the polysiloxane group has a structure containing a polysiloxane bond and containing at least one Si-OR ¹ group. Here, R ¹ is at least one group selected from a hydrogen atom, a substituted or unsubstituted alkyl group, and a substituted or unsubstituted acyl group, and when R ¹ is plural in one molecule, R ¹ May be the same or different. The number of carbon atoms of the alkyl group or acyl group as R ¹ may be an appropriate number depending on the purpose. The carbon number is preferably 1-5. This is because the hydrolysis rate of the R ¹ O group is fast. Specific examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, a propyl group, an iso-propyl group, a butyl group, a sec-butyl group, a tert-butyl group, and a pentyl group. Specific examples of the acyl group having 1 to 5 carbon atoms include an acetyl group and a propionyl group. Specific examples of the substituent for the alkyl group or acyl group include alkoxy groups such as methoxy group and ethoxy group; acyl groups such as acetyl group and propionyl group; and halogens such as chlorine and bromine. R ¹ is preferably a hydrogen atom, a methyl group or an ethyl group, and most preferably a methyl group. This is because the hydrolysis and condensation rate of the R ¹ O group is further increased.

Any appropriate number of Si atoms contained in the polysiloxane group can be adopted depending on the purpose. The average number of Si atoms per polysiloxane group is preferably 4 or more, and more preferably 11 or more. It is because it becomes possible to contain many said Si-OR ¹ groups. The average number of R ¹ O groups in ^one Si—OR group is preferably 5 or more, more preferably 20 or more, per molecule of silicon-containing polymer. Since the R ¹ O group is a functional group that can be hydrolyzed and / or condensed, the greater the number of R ¹ O groups, the more reactive and condensing reaction points, and the stronger the bond between the polymer and the core particles.

  Specific examples of the polysiloxane group include a polymethylmethoxysiloxane group, a polyethylmethoxysiloxane group, a polymethylethoxysiloxane group, a polyethylethoxysiloxane group, a polyphenylmethoxysiloxane group, and a polyphenylethoxysiloxane group.

It is preferable that all the Si atoms in the polysiloxane group are bonded only to the R ¹ O group except for the bond to the organic chain or the polysiloxane bond (Si—O—Si bond). As a result, the ionicity of the Si atom is further increased. As a result, the hydrolysis / condensation rate of the R ¹ O group is increased, and the reactive sites in the silicon-containing polymer are increased, thereby obtaining core particles having a stronger skeleton. Because. Specific examples of such a polysiloxane group include a polydimethoxysiloxane group, a polydiethoxysiloxane group, a polydiiso-propoxysiloxane group, and a poly n-butoxysiloxane group.

  The Si atom in the polysiloxane group may be directly bonded to the organic chain (for example, a Si—C bond may be formed), or may be bonded through any appropriate group or atom ( For example, a Si—O—C bond may be formed). Preferably, the Si atom is directly bonded to the organic chain. This is because the binding site is less susceptible to undesired reactions (for example, hydrolysis and exchange reaction).

  Content of the said polysiloxane group in a silicon-containing polymer becomes like this. Preferably it is 0.5-10 mol%, More preferably, it is 0.5-5 mol%. If it is such a range, the core particle which has desired intensity | strength, a shape, size, etc. will be obtained.

  The molecular weight (number average molecular weight) of the silicon-containing polymer is preferably 200,000 or less, more preferably 50,000 or less, and particularly preferably 10,000 to 30,000. If the molecular weight is too high, it may not dissolve in the organic solvent. If the molecular weight is too low, the amount of polymerizable functional groups introduced may be insufficient.

  The silicon-containing polymer can be produced by any appropriate method. Specific examples include a method of radical (co) polymerizing a radically polymerizable monomer in the presence of a polymerizable polysiloxane. Here, the polymerizable polysiloxane is obtained by partially hydrolyzing and condensing a silane compound and a polymerizable functional group-containing silane coupling agent.

  Any appropriate silane compound can be adopted as the silane compound as long as desired core particles can be obtained. Specific examples of the silane compound include tetramethoxysilane, tetraethoxysilane, ethoxytrimethoxysilane, triethoxymethoxysilane, diethoxydimethoxysilane, tetraiso-propoxysilane, tetrabutoxysilane, trimethoxyhydroxysilane, and triethoxyhydroxysilane. , Methoxytriacetoxysilane, dimethoxydiacetoxysilane, trimethoxyacetoxysilane, and tetraacetoxysilane. Tetramethoxysilane is particularly preferred. A silane compound may be used independently and may be used in combination of 2 or more type.

  Specific examples of the polymerizable functional group-containing silane coupling agent include acryloxypropyltrimethoxysilane, acryloxypropyltriethoxysilane, methacryloxypropyltrimethoxysilane, and methacryloxypropyltriethoxysilane. The polymerizable functional group-containing silane coupling agent may be used alone or in combination of two or more.

  The hydrolysis / condensation reaction between the silane compound and the polymerizable functional group-containing silane coupling agent may be performed under any appropriate conditions. Typically, the hydrolysis / condensation reaction is performed in a solution. Here, the solution is a solution obtained by dissolving a silane compound and a polymerizable functional group-containing silane coupling agent in water and / or an organic solvent. Specific examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene and xylene; esters such as methyl acetate and ethyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran, dioxane and ethyl ether; Examples include alcohols such as methanol, ethanol, iso-propyl alcohol, n-butanol, ethylene glycol and propylene glycol; and halogenated hydrocarbons such as methylene chloride and chloroform. An organic solvent may be used independently and may be used in combination of 2 or more type.

  The hydrolysis / condensation reaction may be carried out without a catalyst or using a catalyst. Preferably, a catalyst is used. Examples of the catalyst include an acidic catalyst and a basic catalyst. Specific examples of the acidic catalyst include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid; organic acids such as acetic acid, propionic acid, oxalic acid, and p-toluenesulfonic acid; and acidic ion exchange resins. Specific examples of basic catalysts include ammonia; organic amine compounds such as triethylamine and tripropylamine; alkali metal compounds such as sodium methoxide, sodium ethoxide, potassium methoxide, potassium ethoxide, sodium hydroxide, and potassium hydroxide. A basic ion exchange resin or the like. Acidic catalysts are preferred. This is because it is easy to control partial hydrolysis / condensation reactions. A catalyst may be used independently and may be used in combination of 2 or more type.

  The reaction temperature of the hydrolysis / condensation reaction is preferably 60 to 100 ° C., and the total reaction time is preferably 3 to 6 hours. The reaction temperature may be controlled to be constant or may be changed stepwise. As described above, a polymerizable polysiloxane is obtained.

  Next, a radically polymerizable monomer is radically (co) polymerized in the presence of the polymerizable polysiloxane to obtain a silicon-containing polymer. Examples of the radical polymerizable monomer include acrylic monomers, styrene monomers, olefin monomers, vinyl monomers, and monomers that form polyester (for example, dicarboxylic acid and diamine). Acrylic monomers are preferred. This is because composite fine particles having an appropriate coating film forming ability can be obtained. Specific examples of acrylic monomers include acrylic carboxylic acids such as (meth) acrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and isopropyl (meth) acrylate. (Meth) acrylic acid such as n-butyl (meth) acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, lauryl tridecyl (meth) acrylate Esters: Epoxy group-containing (meth) acrylic esters such as glycidyl (meth) acrylate; (meth) acrylonitrile, (meth) acrylamide, N-methylolacrylamide, N-butoxymethylacrylamide, diacetone acrylamide, (meth) acrylic acid 2-ethyl sulfonateAn acrylic monomer may be used independently and may be used in combination of 2 or more type. In the present invention, it is preferable to copolymerize the acrylic monomer and an acrylic monomer having a functional group containing active hydrogen. A typical example of an acrylic monomer having a functional group containing active hydrogen is a hydroxyl group-containing acrylic monomer. Specific examples of the hydroxyl group-containing acrylic monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and caprolactone-modified hydroxy (meth) acrylate. (Meth) acrylic acid monoester of ester diol obtained from phthalic acid and propylene glycol.

  The ratio (molar ratio) of acrylic monomer / functional group (for example, hydroxyl group) -containing acrylic monomer in the copolymerization is preferably 90/10 to 20/80, more preferably 70/30 to 40/60. When the ratio of the functional group-containing acrylic monomer is too small, the amount of the polymerizable functional group introduced into the composite fine particles becomes insufficient, and as a result, the curability of the composite fine particles may be insufficient. If the ratio of the functional group-containing acrylic monomer is too large, the stability of the silicon-containing polymer may be insufficient.

  Arbitrary appropriate conditions can be employ | adopted as polymerization conditions of a radically polymerizable monomer (for example, acrylic monomer). In this way, a polymer (silicon-containing polymer) having a functional group containing active hydrogen (for example, a hydroxyl group) and a polysiloxane group in the side chain is obtained.

Next, the silicon-containing polymer is reacted with an isocyanate compound having a polymerizable functional group (preferably an ethylenically unsaturated group) to introduce a polymerizable functional group into the polymer side chain. More specifically, a polymerizable functional group derived from an isocyanate compound is introduced into the polymer side chain by an addition reaction between a functional group (for example, a hydroxyl group) having active hydrogen in the polymer side chain and an isocyanate group. Examples of the polymerizable functional group contained in the isocyanate group include an acryloyl group and a methacryloyl group. Specific examples of the isocyanate compound having a polymerizable functional group include acryloxymethyl isocyanate, methacryloxymethyl isocyanate, acryloxyethyl isocyanate, methacryloxyethyl isocyanate, acryloxypropyl isocyanate, methacryloxypropyl isocyanate, 1,1-bis ( Acryloxymethyl) ethyl isocyanate. A typical reaction scheme is as follows. Arbitrary appropriate conditions can be employ | adopted as reaction conditions of the said addition reaction. In this way, a silicon-containing polymer having a polymerizable functional group in the side chain is obtained.

  Finally, a composite fine particle is obtained by reacting the silicon-containing polymer having a polymerizable functional group in the side chain with a metal compound capable of generating a metal oxide by hydrolysis. A metal compound can be converted into a metal oxide by hydrolysis and further condensed with a polysiloxane group in a polymer side chain to form a three-dimensional network. As a result, core particles having a strong skeleton are formed, and composite fine particles are obtained. Specific examples of such a metal compound include metal halides, metal nitrates, metal sulfates, metal ammonium salts, organometallic compounds, alkoxy metal compounds, and derivatives thereof. A metal compound may be used independently and may be used in combination of 2 or more type.

Preferably, the metal compound is a compound represented by the following general formula (1) or a derivative thereof:
(R ² O) _m MR ³ _3n-m (1)
In the formula (1), M is a group III, group IV or group V metal element of the periodic table, and is preferably at least one metal element selected from Si, Al, Ti and Zr. Each R ² is independently a hydrogen atom, or a substituted or unsubstituted alkyl group or acyl group. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an iso-propyl group, a butyl group, a sec-butyl group, a tert-butyl group, and a pentyl group. Specific examples of the acyl group include an acetyl group and a propionyl group. R ² is particularly preferably a hydrogen atom, a methyl group or an ethyl group, and most preferably a methyl group. This is because the hydrolysis and condensation rate of the R ² O group is fast. R ³ is each independently a substituted or unsubstituted alkyl group, cycloalkyl group, aryl group or aralkyl group. The alkyl group is the same as described above. Specific examples of the cycloalkyl group include a cyclohexyl group. Specific examples of the aryl group include a phenyl group, a tolyl group, and a xylyl group. Specific examples of the aralkyl group include a benzyl group. Examples of the substituent for the alkyl group, cycloalkyl group, aryl group and aralkyl group include alkoxy groups such as methoxy group and ethoxy group, amino group, nitro group, epoxy group and halogen. n is the valence of the metal element M, and m is an integer of 1 to n. When there are a plurality of R ² and / or R ³ in one molecule, R ² and / or R ³ may be the same or different.

  Specific examples of the metal compound include methyltriacetoxysilane, dimethyldiacetoxysilane, trimethylacetoxysilane, tetraacetoxysilane, tetramethoxysilane, tetraethoxysilane, tetraiso-proxysilane, tetrabutoxysilane, methyltrimethoxysilane, Phenyltrimethoxysilane, phenyltriethoxysilane, dimethoxydimethylsilane, dimethoxymethylphenylsilane, trimethylmethoxysilane, trimethylethoxysilane, dimethyldiethoxysilane, dimethoxydiethoxysilane, aluminum trimethoxide, aluminum triethoxide, aluminum triiso -Propoxide, aluminum tributoxide, dimethylaluminum methoxide, tetramethoxytitanium, tetraeth Xititanium, tetraiso-propoxytitanium, tetrabutoxytitanium, tetra (2-ethylhexyloxy) titanium, diethoxysibutoxytitanium, iso-proxy titanium trioctarate, diiso-propoxytitanium diacrylate, tributoxytitanium stearate, Examples include zirconium acetate, tetramethoxyzirconium, tetraethoxyzirconium, tetraiso-propoxyzirconium, and tetrabutoxyzirconium. Specific examples of the derivative of the metal compound represented by the general formula (1) include diiso-propoxytitanium diacetylacetonate, oxytitanium diacetylacetonate, dibutoxytitanium bistriethanolamate, dihydroxytitanium dilactoate, zirconium acetylacetonate. , Acetylacetone zirconium butoxide, triethanolamine zirconium butoxide, and aluminum acetylacetonate.

  The metal compound is particularly preferably a silane compound in which M is Si in the general formula (1) and derivatives thereof. Most preferred are tetramethoxysilane and tetraethoxysilane. This is because it is easily available and does not contain halogen or the like, so that it does not adversely affect the physical properties of the production apparatus and the final product.

  Arbitrary appropriate conditions can be employ | adopted as reaction conditions of the said silicon-containing polymer and the said metal compound. Typically, the reaction is performed in the presence of an organic solvent and / or water. Therefore, the composite fine particles are typically obtained in the form of a dispersion. Specific examples of the solvent are as listed above.

  The ratio of core particles / organic polymer in the composite fine particles obtained as described above is preferably 90/10 to 40/60, more preferably 80/20 to 50/50. When the ratio of the core particles is too high, the introduction amount of the polymerizable functional group may be insufficient, and as a result, the curability of the composite fine particles may be insufficient. When the ratio of the organic polymer is too high, the hardness of the obtained coating film may be insufficient.

D. Coating composition D-1. Coating Composition The coating composition of the present invention includes composite fine particles, a polyfunctional polymerizable compound, and, if necessary, a polymerization initiator and a solvent. A film is formed by polymerizing (curing) the polymerizable functional group (typically, ethylenically unsaturated group) of the composite fine particles and the functional group of the polyfunctional polymerizable compound. The composite fine particles are as described in the above items A to C. The composite fine particles are contained in the composition at a ratio of preferably 20 to 500 parts by weight, more preferably 50 to 300 parts by weight, with respect to 100 parts by weight of the polyfunctional polymerizable compound. Specific examples of the polyfunctional polymerizable compound include polyfunctional (meth) acrylate and urethane (meth) acrylate. A polyfunctional polymerizable compound may be used independently and may be used in combination of 2 or more type.

  Any appropriate (meth) acrylate may be adopted as the polyfunctional (meth) acrylate as long as it has two or more (meth) acrylate groups in the molecule. Specific examples include 1,6-hexanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth). ) Acrylate, tripropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, poly (butanediol) di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, triethylene glycol di (meth) ) Acrylate, triisopropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, bisphenol A di (meth) acrylate and other di (meth) acrylates; Tri (meth) acrylates such as tri (meth) acrylate, pentaerythritol monohydroxytri (meth) acrylate, trimethylolpropane triethoxytri (meth) acrylate; pentaerythritol tetra (meth) acrylate, di-trimethylolpropane tetra ( Tetra (meth) acrylates such as meth) acrylate; penta (meth) acrylates such as dipentaerythritol (monohydroxy) penta (meth) acrylate; hexa (meth) acrylates such as dipentaerythritol hexa (meth) acrylate Can be mentioned.

  As said urethane (meth) acrylate, the compound obtained by making hydroxyl group containing (meth) acrylate and polyisocyanate react can be mentioned, for example. Specific examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxyhexyl (meth) acrylate, and pentaerythritol triacrylate. , Pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, trimethylol, propanediacrylate and the like. A hydroxyl group containing (meth) acrylate may be used independently and may combine 2 or more types. As the polyisocyanate, any of aliphatic, aromatic and alicyclic systems may be used. Specific examples of the polyisocyanate include methylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, dicyclohexylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, and methylene bis. Examples thereof include phenyl diisocyanate. Polyisocyanates that are non-yellowing urethanes are preferred. Polyisocyanate may be used independently and may combine 2 or more types.

  As the combination of the hydroxyl group-containing (meth) acrylate and the polyisocyanate, any appropriate combination can be adopted depending on the purpose. Preferred is a combination of 2-hydroxyethyl acrylate and isophorone diisocyanate, and a combination of 2-hydroxyethyl acrylate and 2,2,4-trimethylhexamethylene diisocyanate.

  As a method for producing urethane (meth) acrylate, for example, the ratio of hydroxyl group in hydroxyl group-containing (meth) acrylate to isocyanate group in polyisocyanate (hydroxyl group: isocyanate group) is 1: 0. Weighing to 8 to 1: 1 and placing in a reaction vessel, adding a catalytic amount of an organic tin compound such as di-n-butyltin dilaurate, and further adding a polymerization inhibitor such as hydroquinone, and a reaction temperature of 30 to 120 ° C. A method of heating and stirring at 50 to 90 ° C. is preferable. The reaction temperature is preferably raised stepwise. The reaction product may contain an oligomerized urethane (meth) acrylate. Examples of commercially available urethane (meth) acrylates include KAYARAD urethane acrylate series (manufactured by Nippon Kayaku Co., Ltd.), Shimitsu series (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and New Frontier R-1000 series (Daiichi Kogyo). Pharmaceutical Co., Ltd.), UA-306H, UF-8001 (manufactured by Kyoeisha Chemical Co., Ltd.), NK Oligo U series, NK Oligo UA series (manufactured by Shin-Nakamura Chemical Co., Ltd.) and the like.

  Any appropriate type of initiator may be employed as the polymerization initiator depending on the purpose. Specific examples of the polymerization initiator include a thermal polymerization initiator and a photopolymerization initiator. A polymerization initiator may be used independently and may be used in combination of 2 or more type. In the coating composition of the present invention, a photopolymerization initiator is preferred. Specific examples of the photopolymerization initiator include benzoin compounds, acetophenone compounds, benzophenone compounds, anthraquinone compounds, phosphine oxide compounds, xanthone compounds, thioxanthone compounds, and ketal compounds. Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl) Propionyl) -benzyl] -fe L} -2-methylpropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholinophenyl) -butan-1-one, benzophenone, p-phenylbenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, 4,4′-diethylaminobenzophenone, dichlorobenzophenone 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiarybutylanthraquinone, 2-aminoanthraquinone, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) ) -Phenylphosphine oxide, , 4,6-trimethylbenzoyldiphenylphosphine oxide, xanthone, thioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, Examples include benzyl dimethyl ketal and acetophenone dimethyl ketal. Examples of commercially available products include Irgacure 127, 184, 369, 379, 500, 651, 784, 819, 851, 907, 1300, 1800, 1870, 2959, OXE01, OXE02, DAROCUR1173 (above, manufactured by Ciba Specialty Chemicals), etc. Is mentioned. The polymerization initiator is contained in the composition at a ratio of preferably 0.1 to 20 parts by weight, more preferably 1 to 10 parts by weight, with respect to 100 parts by weight of the solid content of the coating composition.

  Any appropriate solvent can be adopted as the solvent as long as the composite fine particles and the polyfunctional polymerizable compound can be dispersed. Specific examples of the solvent include those listed in the above section C.

  The coating composition of the present invention may further contain any appropriate monofunctional polymerizable compound depending on the purpose. Specific examples of the monofunctional polymerizable compound include acrylamide, (meth) acryloylmorpholine, 7-amino-3,7-dimethyloctyl (meth) acrylate, isobutoxymethyl (meth) acrylate, and isobornyloxyethyl (meth). Acrylate, isobornyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ethyldiethylene glycol (meth) acrylate, t-octyl (meth) acrylamide, diacetone (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) Acrylate, lauryl (meth) acrylate, dicyclopentadiene (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, N, N-dimethyl (meth) acrylamide Tetrachlorophenyl (meth) acrylate, 2-tetrachlorophenoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, tetrabromophenyl (meth) acrylate, 2-tetrabromophenoxyethyl (meth) acrylate, 2-trichlorophenoxyethyl (Meth) acrylate, tribromophenyl (meth) acrylate, 2-tribromophenoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, vinylcaprolactam, N-vinylpyrrolidone, Phenoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, pentachlorophenyl (meth) acrylate, pentabromophenyl (meth) acrylate , Polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, bornyl (meth) acrylate, and compounds represented by methyl triethylene diglycol (meth) acrylate.

  The coating composition of the present invention may further contain any appropriate additive depending on the purpose. Specific examples of additives include leveling agents, pigments, pigment dispersants, UV absorbers, antioxidants, viscosity modifiers, light stabilizers, metal deactivators, peroxide decomposing agents, fillers, and reinforcement. Agent, plasticizer, lubricant, anticorrosive agent, rust inhibitor, emulsifier, mold release agent, fluorescent whitening agent, organic flame retardant, inorganic flame retardant, anti-dripping agent, melt flow modifier, electrostatic Examples thereof include an inhibitor, a slipping imparting agent, an adhesion imparting agent, an antifouling agent, a surfactant, an antifoaming agent, a polymerization inhibitor, a photosensitizer, a surface improver, and a silane coupling agent. In addition, when using an ultraviolet absorber, it cannot be overemphasized that it is used in the quantity of the grade which does not inhibit the superposition | polymerization (hardening) reaction of composite fine particles and a polyfunctional polymerizable compound.

  The coating composition of the present invention may further contain any appropriate organic or inorganic fine particles. Typically, such organic or inorganic fine particles are used to impart functions (for example, refractive index adjustment, conductivity, antiglare property) according to the purpose to the obtained coating layer. Specific examples of fine particles useful for increasing the refractive index of the coating layer and imparting conductivity include zinc oxide, titanium oxide, zirconium oxide, aluminum oxide, tin oxide, tin-doped indium oxide, antimony-doped tin oxide, indium-doped zinc oxide, Examples include indium oxide and antimony oxide. Specific examples of the fine particles useful for lowering the refractive index of the coating layer include magnesium fluoride, silica, and hollow silica. Specific examples of the fine particles useful for imparting antiglare properties include inorganic particles such as calcium carbonate, barium sulfate, talc and kaolin; silicon resin, melamine resin, benzoguanamine resin, acrylic resin, polystyrene resin and the like in addition to the fine particles described above. Organic fine particles such as these copolymer resins can be mentioned. These fine particles may be used alone or in combination of two or more.

  The coating composition of the present invention is, for example, a hard coating agent such as a transfer foil film, a plastic optical component, a touch panel, a film-type liquid crystal element, a plastic molding, a low refractive index coating agent for an antireflection film, and a coating agent for a light diffusion film. Can be suitably used.

D-2. Low Refractive Index Coating Composition As described above, the coating composition of the present invention can be suitably used as a low refractive index coating agent. In the present specification, such a composition is referred to as a “low refractive index coating composition”. The refractive index at a wavelength of 550 nm of a film having a thickness of 0.1 μm formed by the low refractive index coating composition of the present invention is preferably 1.25 to 1.40, more preferably 1.25 to 1. 35. By using the composite fine particles of the present invention, such refractive index is expressed by voids in the composite fine particles and / or in the film formed from the low refractive index coating composition containing the composite fine particles.

  The composite fine particles are basically as described in the above sections A to C, but when used in the low refractive index coating composition, the organic polymer preferably has a portion containing a fluorine atom. This is because the refractive index of the composite fine particles is lowered and the refractive index of the coating film can be further lowered. Such composite fine particles can be obtained by copolymerizing a radical polymerizable monomer containing a fluorine atom when producing a silicon-containing polymer. The radically polymerizable monomer containing a fluorine atom can be copolymerized in a proportion of preferably 3 to 95 parts by weight, more preferably 5 to 80 parts by weight, based on 100 parts by weight of the total amount of radically polymerizable monomers. If it is less than 3 parts by weight, there is a possibility that it does not sufficiently contribute to lowering the refractive index. If it exceeds 95 parts by weight, the particles tend to aggregate. As the radical polymerizable monomer containing a fluorine atom, an acrylic monomer having a perfluoroalkyl group is preferred. As the perfluoroalkyl group, a perfluoromethyl group, a perfluoroethyl group, a perfluorobutyl group, a perfluorohexyl group, a perfluorooctyl group, a perfluorodecyl group, a perfluorododecyl group, and a perfluorotetradecyl group are preferable. Such a monomer may be used independently and may be used in combination of 2 or more type. Specific examples of the acrylic monomer having a fluorine atom include 2,2,2-trifluoroethyl (meth) acrylate and perfluorooctylethyl (meth) acrylate.

  In the low refractive index coating composition, the composite fine particles are contained in the composition at a ratio of preferably 100 to 500 parts by weight, more preferably 100 to 300 parts by weight with respect to 100 parts by weight of the polyfunctional polymerizable compound. Contained. If it is 100 parts by weight or less, there is a possibility that voids in the coating are not filled with the polyfunctional polymerizable compound and the refractive index is not lowered. If it is 500 parts by weight or more, the scratch resistance of the film may be insufficient.

E. Optical film E-1. Outline of Optical Film The optical film of the present invention includes a coating layer of the coating composition. In this specification, the term “coating composition” includes both the coating composition described in the above section D-1 and the low refractive index coating composition described in the section D-2. Typically, this optical film includes a substrate and a coating layer. The coating layer is typically formed by applying the coating composition and then drying and curing. A typical example of the substrate is a plastic film. Specific examples include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene film, polypropylene film, cellophane, diacetyl cellulose film, triacetyl cellulose film, acetyl cellulose butyrate film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl Alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyetheretherketone film, polyethersulfone film, polyetherimide film, polyimide film, fluororesin film, nylon A film, an acrylic resin film, etc. are mentioned. A polyethylene terephthalate film, a polyethylene naphthalate film, a triacetyl cellulose film, a polycarbonate film, and an acrylic resin film are preferable. It is because it is easily available and excellent in transparency. The base material may be a sheet shape or a plate shape depending on the application.

  Preferably, the substrate can be subjected to any appropriate surface treatment depending on the purpose. Specific examples of surface treatment include surface concavo-convex treatment by sandblasting, solvent treatment, etc .; surface oxidation treatment such as corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment; resin composition For example, primer treatment with a product.

  Any appropriate application method can be adopted as the application method of the coating composition. Specific examples include spin coating, dipping, spraying, slide coating, bar coating, roll coating, gravure coating, meniscus coating, flexographic printing, screen printing, and bead coating.

Arbitrary appropriate methods and conditions can be employ | adopted as said drying and hardening method. Typically, after applying the coating composition, the solvent is evaporated and dried at 0 to 200 ° C., and a curing treatment is performed with heat and / or radiation. In the case of radiation, it is preferable to use ultraviolet rays or electron beams. When using the coating composition of this invention, the hardening process by an ultraviolet-ray is especially preferable. In this case, the irradiation amount of ultraviolet rays is preferably 10 to 10,000 mJ / cm ² , more preferably 100 to 2000 mJ / cm ² . In one embodiment, the ultraviolet irradiation is performed in a state where part or all of the atmosphere is replaced with an inert gas. As a result, oxygen inhibition at the surface can be suppressed. As the inert gas, nitrogen gas is preferable. The thickness of the coating layer to be formed can vary depending on the purpose, but is preferably 50 nm to 100 μm.

  Specific examples of the optical film include a hard coat film, an antiglare film, an antireflection film, a polarizing plate, an optical filter, and a light diffusion film used in an image display device. Specific examples of the image display device include a liquid crystal display device (LCD), a cathode ray tube display device (CRT), a plasma display panel (PDP), and an electroluminescence display (ELD). Hereinafter, typical optical films will be specifically described.

E-2. Hard Coat Film In one embodiment, the optical film of the present invention is a hard coat film. The hard coat film is a film imparted with physical strength by applying the above coating composition to a substrate and then drying and curing to form a hard coat layer.

  The thickness of the hard coat layer can be appropriately designed according to the application. The thickness of the hard coat layer is preferably 1 to 10 μm, more preferably 1 to 5 μm. The strength of the hard coat layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in a pencil hardness test according to JIS K5400. If necessary, the hard coat film may contain any appropriate additive in the substrate and / or the hard coat layer, and further has any appropriate coating layer on the surface of the hard coat layer. Also good. The coating layer may be a single layer or two or more layers. By using the additive and / or the coating layer, for example, performance such as antistatic property, antifouling property, slipperiness and antiglare property can be imparted. Alternatively, antiglare properties can be imparted by forming irregularities on the surface of the hard coat layer. The hard coat layer imparted with the antiglare property can be suitably used, for example, as an antiglare layer of an antireflection film. A film having a hard coat layer imparted with an antiglare property can be suitably used as an antiglare film, for example. Furthermore, such a hard coat film can also be used as a base material for an antireflection film.

E-3. Antireflection Film In another embodiment, the optical film of the present invention is an antireflection film. The antireflection film is a laminate having a low refractive index layer formed by applying the low refractive index coating composition on at least one side of a substrate, followed by drying and curing. The low refractive index layer may be formed directly on the substrate, or may be formed via another layer. The other layer may be a single layer or two or more layers. Specific examples of the other layer include a layer having a refractive index different from that of the low refractive index layer. In the antireflection film of the present invention, the refractive index of the other layers is often larger than the refractive index of the low refractive index layer. By providing such a layer, reflection can be reduced in a wider wavelength range. Furthermore, the low refractive index layer can be preferably formed as the outermost layer of the antireflection film. Therefore, specific examples of the preferred laminated structure of the antireflection film include base material / low refractive index layer, base material / high refractive index layer / low refractive index layer, base material / medium refractive index layer / high refractive index layer / low. Examples include a refractive index layer. In the present specification, the high refractive index layer means a layer having a higher refractive index than the low refractive index layer, and the middle refractive index layer is higher than the low refractive index layer and has a high refractive index layer. Refers to a layer having a lower refractive index. The thickness of the medium refractive index layer or the high refractive index layer is preferably 0.05 to 0.20 μm. The refractive index of the middle refractive index layer or the high refractive index layer is preferably 1.45 to 2.00. More specifically, the refractive index of the middle refractive index layer is preferably 1.45 to 1.80, and the refractive index of the high refractive index layer is preferably 1.60 to 2.00. In one embodiment, the middle refractive index layer or the high refractive index layer may be formed from a composition comprising a polyfunctional polymerizable compound and high refractive index fine particles. Specific examples of the polyfunctional polymerizable compound include polyfunctional (meth) acrylate and urethane (meth) acrylate. Typical examples of the high refractive index fine particles include metal oxide fine particles. Specific examples include zinc oxide, titanium oxide, zirconium oxide, aluminum oxide, tin oxide, tin-doped indium oxide, indium-doped zinc oxide, indium oxide, and antimony oxide. By adjusting the content of the fine particles, the refractive index of the medium refractive index layer or the high refractive index layer can be controlled. By imparting conductivity to the fine particles, the medium refractive index layer or the high refractive index layer can also function as an antistatic layer. In another embodiment, the medium refractive index layer or the high refractive index layer has a high refractive index such as titanium oxide or zirconium oxide formed by a vapor deposition method such as chemical vapor deposition (CVD) or physical vapor deposition (PVD). It can be set as the vapor deposition film of an inorganic oxide.

  The antireflection film of the present invention may have still another layer having any appropriate function depending on the purpose. The further other layer is provided at any appropriate position of the laminate according to the purpose. Specific examples of the other layers include a hard coat layer, an antiglare layer, an antistatic layer, and an antifouling layer. The hard coat layer is preferably formed using a coating agent containing a polyfunctional polymerizable compound. Specific examples of the polyfunctional polymerizable compound include polyfunctional (meth) acrylate and urethane (meth) acrylate. The antiglare layer is preferably formed using a coating agent containing particles and a polyfunctional polymerizable compound. Various inorganic particles, organic particles, and organic / inorganic composite particles can be used as the particles. The hard coat layer and the antiglare layer described in the above section E-2 can also be used as the hard coat layer and the antiglare layer.

The antistatic layer prevents the generation of static electricity, thereby preventing dust and dirt from adhering to the antireflection film, and / or external electrostatic interference when the antireflection film is incorporated in an image display device. To prevent. As the performance of the antistatic layer, the surface resistance after formation of the antireflection film is preferably 10 ¹² Ω / □ or less. Even if the surface resistance is 10 ¹² Ω / □ or more, the adhesion of dust and dust can be improved to some extent as compared with the case where no antistatic layer is provided.

  The antistatic layer is generally formed from an antistatic resin composition containing a film forming component (typically a resin component) and an antistatic agent. Any appropriate resin capable of forming a film may be employed as the resin component. Specific examples of the antistatic agent include a cationic antistatic agent having a cationic group such as a quaternary ammonium salt, a pyridinium salt, and first to third amino groups; a sulfonate group, a sulfate ester base, and a phosphate ester base. Anionic antistatic agents having an anionic group such as phosphonic acid group; amphoteric antistatic agents such as amino acid type and aminosulfate ester type; nonionic antistatic agents such as amino alcohol type, glycerin type and polyethylene glycol type; Surfactant-type antistatic agents such as organometallic compounds (for example, tin or titanium alkoxides) or metal chelate compounds (for example, acetylacetonate salts of organometallic compounds); and high molecular weights of the above antistatic agents Examples thereof include molecular type antistatic agents. Also, polymerizable antistatic agents such as tertiary amino groups, quaternary ammonium groups or monomers or oligomers having a metal chelate moiety and a polymerizable functional group, and organometallic compounds such as coupling agents having a polymerizable functional group Agents can also be used. Further, metal oxide fine particles such as zinc oxide, titanium oxide, tin oxide, tin-doped indium oxide, antimony-doped tin oxide, indium-doped zinc oxide, indium oxide, and antimony oxide can be used. By containing the antistatic agent in the coating composition, the hard coat layer and the antiglare layer can also serve as the antistatic layer.

  The antireflection film of the present invention is preferably as the total light transmittance is higher and / or the haze is lower. Therefore, it is desirable that each layer constituting the antireflection film (laminate) is as excellent as possible in transparency.

E-4. Polarizing plate In yet another embodiment, the optical film of the present invention is a polarizing plate. The polarizing plate has a polarizer and the antireflection film provided on at least one of the polarizers. The antireflection film also serves as a protective film for the polarizing plate. As the polarizer, any appropriate polarizer can be used as long as it has a polarization function (a function of allowing only light having a polarization plane in a certain direction to pass). A typical example of the polarizer is a polyvinyl alcohol polarizing film. The polyvinyl alcohol polarizing film is typically a stretched film of a polyvinyl alcohol film containing a dichroic substance (typically iodine or a dichroic dye). The polyvinyl alcohol polarizing film is formed by forming a polyvinyl alcohol aqueous solution and uniaxially stretching it while immersing it in, for example, an iodine solution, or uniaxially stretching after dyeing, and is preferably subjected to a durability treatment with a boron compound. Is used.

  The polarizing plate of the present invention can be produced by any appropriate method. For example, the antireflection film of the present invention may be treated with an alkali and bonded to both surfaces of the polyvinyl alcohol polarizing film using a completely saponified polyvinyl alcohol adhesive (water-soluble adhesive). The alkali treatment refers to a treatment in which the antireflection film is immersed in a high-temperature strong alkaline solution in order to improve the wettability of the adhesive and improve the adhesiveness. At this time, by providing a peelable protective film (for example, a polyester resin film such as polyethylene terephthalate) on the surface of the low refractive index layer of the antireflection film, it can be protected from erosion due to dirt or alkali.

E-5. Optical Filter for Plasma Display In yet another embodiment, the optical film of the present invention is an optical filter for plasma display (PDP). The optical filter for PDP typically has a support and an antireflection film provided on the support. Specific examples of the support include glass. The antireflection film is preferably the antireflection film described in the above section E-3. By using the antireflection film of the present invention, an optical filter for PDP having excellent antireflection performance and excellent scratch resistance can be obtained. The low refractive index coating composition may be directly applied to a support to form a low refractive index layer.

  Preferably, the PDP optical filter further has a near-infrared absorbing film, an electromagnetic wave shielding film and / or a visible light absorbing film on the support. These films are typically provided between the support and the antireflection film. PDP has a problem that near infrared rays having a wavelength of 800 nm to 1000 nm are generated during plasma discharge, and this near infrared rays cause malfunction of a remote control for home appliances. By providing a near-infrared absorbing film, such a problem can be reduced or eliminated. The PDP performs plasma discharge in a gas mainly composed of a rare gas (particularly neon) sealed inside the panel, and R, G, B provided in the cells inside the panel by vacuum ultraviolet rays generated at that time. In this light emission process, electromagnetic waves unnecessary for the operation of the PDP are simultaneously emitted. By providing an electromagnetic wave shielding film, such a problem can be reduced or eliminated.

  The near infrared absorbing film is typically formed from a composition containing a near infrared absorbing dye and a binder. Specific examples of the near infrared absorbing dye include dyes such as cyanine, polymethine, squarylium, porphyrin, dithiol metal complex, phthalocyanine, and diimonium. Any appropriate resin can be adopted as the binder. A resin capable of forming a highly transparent film is preferred. Specific examples include polyolefin resins such as polyethylene; styrene resins; vinyl resins such as (meth) acrylic acid ester polymers; polyamide resins such as nylon; polyurethane resins; polyester resins; polycarbonate resins; Resin, polyvinyl acetal resin.

  As a specific example of the electromagnetic wave shielding film, a film obtained by patterning a metal mesh on a film by a technique such as etching or printing and smoothing with a resin; a metal vapor deposited on a fiber mesh in a resin An embedding film is mentioned.

  The optical filter for PDP of the present invention may further have a shock absorbing layer. Alternatively, the shock absorbing layer may be used instead of the support. It is preferable to use it instead of the support. The impact absorbing layer is used to protect the PDP from external impacts. Examples of the material constituting the shock absorbing layer include ethylene-vinyl acetate copolymer, acrylic resin, polyvinyl chloride, urethane resin, and silicon resin. Details of the material constituting the shock absorbing layer are described in, for example, Japanese Patent Application Laid-Open No. 2004-246365 or Japanese Patent Application Laid-Open No. 2004-264416.

  The optical filter for PDP of the present invention may have any appropriate configuration (laminated structure) depending on the purpose. Typical configurations include antireflection film / near infrared absorption film / support, antireflection film / near infrared absorption film / electromagnetic wave shielding film / support, antireflection film / electromagnetic wave shielding film / near infrared absorption film / support. Is mentioned.

  For example, an optical filter for PDP having the configuration of an antireflection film / near infrared absorption film / support can be produced by the following method: (i) Applying the above composition on the support side of the antireflection film and drying Forming a laminate of an antireflection film / near-infrared absorbing film and laminating the laminate on a support, or (ii) applying and drying the composition on the support and drying the support / near A method of forming a laminate of infrared absorbing films and laminating an antireflection film on the laminate. In the lamination, the films to be laminated may be bonded with an adhesive or an adhesive, or may be bonded by heating and melting each film. At the time of lamination, the surface of each film may be subjected to physical treatment (for example, corona treatment, plasma treatment), and an anchor coat layer (for example, highly polar polymer such as polyethyleneimine, oxazoline polymer, polyester, cellulose, etc.) It may be formed.

  The PDP optical filter of the present invention may be used by being placed on the front side of the PDP, or may be used by being bonded via an adhesive or a pressure-sensitive adhesive.

F. Image Display Device The image display device of the present invention includes the optical film. Preferably, the image display device of the present invention includes at least one selected from the antireflection film, the polarizing plate, and the optical filter. In one embodiment, the image display device has the antireflection film on the outermost surface. According to such an embodiment, external light reflection can be satisfactorily reduced. In another embodiment, the image display device includes the antireflection film on one or more surfaces of a component that is provided therein and has an interface with air. According to such an embodiment, the reflected light inside the apparatus can be satisfactorily reduced.

The operation of the present invention will be described below.
According to the present invention, by introducing a polymerizable functional group (preferably an ethylenically unsaturated group) into the side chain of the organic polymer bonded to the surface of the core particle, the amount of polymerizable functional group introduced into the composite fine particles is conventionally reduced. Compared to the above, it can be remarkably increased. As a result, composite fine particles having excellent curability (hardness, wear resistance, scratch resistance) can be obtained. Conventionally, even when trying to introduce a polymerizable functional group into a side chain using a polyfunctional acrylate or the like, gelation occurs when a large amount is introduced, and it is practically impossible to introduce a large amount of functional groups. Met. On the other hand, according to the present invention, a polymerizable functional group is obtained by reacting an active hydrogen-containing functional group (preferably a hydroxyl group) in the side chain of a silicon-containing polymer (which finally becomes an organic polymer) with an isocyanate compound. Can be introduced in large quantities.
Furthermore, the polymerizable functional group is not directly bonded to the core particle, but is located away from the core particle via the organic polymer, and the organic polymer main chain is flexible, so that it can be cured. The reaction rate of the polymerizable functional group is very high. As a result, a film having a very excellent hardness can be obtained.
In a preferred embodiment, the polymerizable functional group is bonded to the organic polymer main chain via a urethane bond. As a result, solubility and dispersibility in a solvent are ensured mainly due to the organic polymer main chain, and adhesion is largely improved mainly due to the urethane bond. Therefore, composite fine particles that can achieve both adhesion and dispersion stability can be obtained. Furthermore, volume shrinkage after curing can be significantly reduced by having excellent adhesion. In addition, in general, when a thin film is formed, it is easily affected by oxygen inhibition during curing. However, according to the present invention, the urethane group is unevenly distributed on the surface of the composite fine particles, thereby affecting the oxygen inhibition. It becomes hard to receive, and the sclerosis | hardenability at the time of thin film formation is improved.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples. Unless otherwise specified, parts and% in the examples are based on mass. Moreover, the evaluation items in the examples are as follows.

(1) Pencil hardness A pencil scratch test was performed in accordance with JIS-K5400, and evaluation by scratches was performed.
(2) Steel Wool Resistance Using Suga Test Machine Co., Ltd., Gakushin Type Abrasion Resistance Tester, how to scratch # 0000 steel wool after reciprocating 10 or 20 times with a load of 200 g Visually evaluated. The case where there was no scratch was A, the case where the scratch was 1 to 10 was B, and the case where the scratch was 11 or more was C.
(3) Haze It measured using the haze meter (Nippon Denshoku Co., Ltd. product, NDH2000) based on JIS-K7105.
(4) Total light transmittance Based on JIS-K7361, it measured using the haze meter (Nippon Denshoku Co., Ltd. product, NDH2000).
(5) Appearance The appearance of the coating film surface was visually observed to evaluate coating unevenness. The case where no coating unevenness was observed was rated as ◯, the case where coating unevenness was observed as Δ, and the case where remarkable coating unevenness was observed as ×.
(6) Luminous reflectance The reflectance was measured using a spectrophotometer (manufactured by Shimadzu Corporation, UV3700), and the luminous reflectance was obtained from the reflectance measurement result.
(7) Stability 30 ml of the coating composition was stored at room temperature in the dark. One week later, the presence or absence of aggregates was observed, and those where no aggregates were confirmed were marked with ◯, and those where aggregates were confirmed were marked with x.
(8) Refractive index Using an interference-type film thickness measuring device (F20, manufactured by Filmetrics), the reflectance of the film is measured in the range of 400 to 800 nm, the nk-Cauchy dispersion formula is cited, and the unknown parameters are The refractive index at a wavelength of 550 nm of the coating film (coating layer) was obtained from the measured value of the reflectance spectrum by a non-linear least square method.

Reference Example 1: Synthesis of polymerizable polysiloxane (M-1) In a 300 ml four-necked flask equipped with a stirrer, a thermometer and a condenser tube, 144.5 g of tetramethoxysilane and 23.6 g of γ-methacryloxypropyltrimethoxysilane 19.0 g of water, 30.0 g of methanol, and 5.0 g of Amberlyst 15 (trade name, cation exchange resin manufactured by Organo) were stirred and reacted at 65 ° C. for 2 hours. After the reaction mixture was cooled to room temperature, a distillation column, a cooling tube connected to the distillation column and an outlet were provided instead of the cooling tube, and the temperature inside the flask was raised to about 80 ° C. over 2 hours under normal pressure. Was kept at the same temperature until no more spilled. Furthermore, the reaction was further proceeded by holding at a pressure of 2.67 × 10 kPa and a temperature of 90 ° C. until methanol did not flow out. After the reaction mixture was cooled again to room temperature, Amberlyst 15 was filtered off to obtain a polymerizable polysiloxane (M-1) having a number average molecular weight of 1,800.

Reference Example 2: Synthesis of silicon-containing polymer (P-1) 260 g of butyl acetate as an organic solvent was placed in a 1 liter flask equipped with a stirrer, a dripping port, a thermometer, a condenser tube and a nitrogen gas inlet, and nitrogen gas was added. The temperature inside the flask was heated to 95 ° C. with stirring. Next, a solution prepared by mixing 12 g of polymerizable polysiloxane (M-1), 112 g of butyl acrylate, 187 g of 2-hydroxyethyl methacrylate and 2.5 g of 2,2′-azobis (2-methylbutyronitrile) was added through the dropping port 3 It was added dropwise over time. After the dropwise addition, stirring was continued for 1 hour at the same temperature. Then, 0.2 g of 2,2′-azobis (2-methylbutyronitrile) was added to the reaction mixture twice every 30 minutes, and the reaction mixture was further added for 2 hours. Copolymerization was performed by heating to obtain a solution in which a silicon-containing polymer (P-1) having a number average molecular weight of 12,000 and a weight average molecular weight of 27,000 was dissolved in butyl acetate. The solid content of the obtained solution was 48.2%.

Reference Example 3: Synthesis of unsaturated group-containing silicon-containing polymer (P-2) A silicon-containing polymer (P-1) was added to a 1-liter flask equipped with a stirrer, a dripping port, a thermometer, a cooling pipe, and a nitrogen gas inlet. 400 g was added, nitrogen gas was introduced, and the temperature inside the flask was heated to 70 ° C. while stirring. Next, 55 mg of dibutyltin laurate was added to the flask, and then a butyl acetate solution of 142 g of acryloxyethyl isocyanate (Karenz AOI, Showa Denko KK) was added dropwise over 1 hour with stirring. After completion of the dropwise addition, stirring was continued for 6 hours at the same temperature to advance the reaction. After the reaction, methanol was added to the system to adjust the solid content to 45% to obtain a solution in which the unsaturated group-containing silicon-containing polymer (P-2) was dissolved in butyl acetate.

(Preparation of composite fine particle dispersion)
200 g of butyl acetate and 50 g of methanol were charged into a 500 ml four-necked flask equipped with a stirrer, two dropping ports (dropping port a and dropping port b), and a thermometer, and the internal temperature was adjusted to 40 ° C. Next, while stirring the inside of the flask, 10 g of a butyl acetate solution of unsaturated group-containing silicon-containing polymer (P-2), 18 g of tetramethoxysilane and 5 g of butyl acetate (raw material liquid A) were added from the dropping port a to 25 A mixed liquid (raw material liquid B) of 5 g% ammonia water, 15 g methanol, and 10 g deionized water was dropped from the dropping port b over 2 hours. After dropping, a distillation column, a cooling tube connected to the distillation column and an outlet are provided instead of the cooling tube, and the temperature inside the flask is raised to 70 ° C. under a pressure of 40 kPa. The mixture was distilled off to 30% to obtain a dispersion (S-1) in which composite fine particles were dispersed in butyl acetate. The obtained composite fine particles had an average particle size of 22.1 nm and an inorganic core particle / organic polymer ratio of 61/39. Evaluation was performed by the following method.

(Measurement of the ratio of inorganic core particles to organic polymer)
Elemental analysis was performed on the composite fine particle dispersion (S-1) dried at 130 ° C. for 24 hours under a pressure of 1.33 × 10 kPa, and ash was determined as the content of inorganic core particles in the composite fine particles.
(Measurement of average particle size)
Using a solution obtained by diluting 1 g of the composite fine particle dispersion (S-1) with 99 g of n-butyl acetate, the particles were photographed with a transmission electron microscope, the diameters of 100 randomly selected particles were read, and the average Was determined as the average particle size.

(Preparation and evaluation of coating composition)
A solution of 7 g of dipentaerythritol hexaacrylate (DPE-6A, manufactured by Kyoeisha Chemical Co., Ltd.) dissolved in 20 g of methyl ethyl ketone, a solution of 0.7 g of photopolymerization initiator (Irgacure 907, manufactured by Ciba Specialty Chemicals) dissolved in 8 g of methyl ethyl ketone, And 50 g of the composite fine particle dispersion (S-1) were mixed to prepare a coating composition. The formulation of the composition is shown in Table 1 below together with the formulation of the compositions of Examples 2 to 11 and Comparative Examples 1 to 3 described later.

The coating composition was applied to a polyethylene terephthalate film (Cosmo Shine A4300, manufactured by Toyobo Co., Ltd .: thickness 188 μm) using a bar coater. The coating layer was dried at 100 ° C. for 15 minutes and then cured by irradiating with 250 mJ / cm ² of ultraviolet light with a high-pressure mercury lamp to form a hard coat layer having a thickness of 2.8 μm. The obtained hard coat layer was evaluated for pencil hardness, steel wool resistance, haze, total light transmittance and appearance. The evaluation results are shown in Table 2 together with the results of Examples 2 to 11 and Comparative Examples 1 to 3 described later.

(Comparative Example 1)
In a dry air, 96 parts of hexamethylene diisocyanate was added dropwise at 50 ° C. over 1 hour with stirring to a solution consisting of 110 parts of mercaptopropyltrimethoxysilane and 0.5 parts of dibutyltin laurate, and then at 70 ° C. for 3 hours. Stir with heating. To this, 277 parts of pentaerythritol triacrylate (PE-3A, manufactured by Kyoeisha Chemical Co., Ltd.) was added dropwise at 30 ° C. over 1 hour, and then heated and stirred at 60 ° C. for 10 hours to obtain silane compound A. Under a nitrogen stream, a mixed solution of 30 parts of the resulting silane compound A, 233 parts of MEK-ST (manufactured by Nissan Chemical Co., Ltd., methyl ethyl ketone-dispersed colloidal silica, silica concentration 30%), 5 parts of isopropyl alcohol and 3 parts of ion-exchanged water was added. The mixture was stirred at 0 ° C. for 3 hours, 18 parts of orthoformate methyl ester was added, and the mixture was further heated and stirred at the same temperature for 1 hour to obtain a colorless transparent dispersion (S-2).
A coating composition was prepared and a hard coat layer was formed in the same manner as in Example 1 except that this dispersion (S-2) was used and the formulation shown in Table 1 was used. This hard coat layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

(Comparative Example 2)
Under a nitrogen stream, 30 parts of 2-acryloyloxyethyl isocyanate (Karenz AOI, Showa Denko), 400 parts of MEK-ST (Nissan Chemical Co., Ltd., methyl ethyl ketone-dispersed colloidal silica, silica concentration 30%) and dibutyltin laurate 05 parts were added and stirred at 20 ° C. for 24 hours. After the reaction, the mixture was diluted with methanol so that the solid content was 30% to obtain a dispersion (S-3).
A coating composition was prepared and a hard coat layer was formed in the same manner as in Example 1 except that this dispersion (S-3) was used and the formulation shown in Table 1 was used. This hard coat layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

(Comparative Example 3)
Under a nitrogen stream, 28 parts of 3-acryloyloxypropyltrimethoxysilane (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.), 400 parts of MEK-ST (manufactured by Nissan Chemical Co., Ltd., methyl ethyl ketone-dispersed colloidal silica, silica concentration 30%) and 0 8 parts of 0.002N hydrochloric acid was added and stirred for 24 hours to obtain a dispersion (S-4).
A coating composition was prepared and a hard coat layer was formed in the same manner as in Example 1 except that this dispersion (S-4) was used and the formulation shown in Table 1 was used. This hard coat layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

A composite fine particle dispersion (S-5) was obtained in the same manner as in Example 1 except that the amount of the butyl acetate solution of the unsaturated group-containing silicon-containing polymer (P-2) was changed from 10 g to 4 g. The average particle diameter of the obtained composite fine particles was 15.3 nm, and the ratio of inorganic core particles / organic polymer was 80/20.
A coating composition was prepared and a hard coat layer was formed in the same manner as in Example 1 except that this dispersion (S-5) was used. This hard coat layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

A silicon-containing polymer was obtained in the same manner as in Reference Example 2 except that lactone-modified methacrylate (Daicel Chemical Industries, Plaxel FM-1) was used instead of 2-hydroxyethyl methacrylate. This silicon-containing polymer had a number average molecular weight of 15,000 and a weight average molecular weight of 29,000. A solution in which the unsaturated group-containing silicon-containing polymer was dissolved in butyl acetate was obtained in the same manner as in Reference Example 3 except that this silicon-containing polymer was used. A composite fine particle dispersion (S-6) was obtained in the same manner as in Example 1 except that this unsaturated group-containing silicon-containing polymer solution was used. The obtained composite fine particles had an average particle size of 23.5 nm and an inorganic core particle / organic polymer ratio of 61/39.
A coating composition was prepared and a hard coat layer was formed in the same manner as in Example 1 except that this dispersion (S-6) was used. This hard coat layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

An unsaturated group-containing silicon-containing polymer was prepared in the same manner as in Reference Example 3 except that 1,1-bis (acryloxymethyl) ethyl isocyanate (Karenz BEI, Showa Denko) was used instead of acryloxyethyl isocyanate. A solution dissolved in butyl acetate was obtained. A composite fine particle dispersion (S-7) was obtained in the same manner as in Example 1 except that this unsaturated group-containing silicon-containing polymer solution was used. The average particle diameter of the obtained composite fine particles was 25.2 nm, and the ratio of inorganic core particles / organic polymer was 61/39.
A coating composition was prepared and a hard coat layer was formed in the same manner as in Example 1 except that this dispersion (S-7) was used. This hard coat layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

Use of butyl acetate solution of unsaturated group-containing silicon-containing polymer (P-2) A composite fine particle dispersion (S-8) was obtained in the same manner as in Example 1 except that this dose was changed from 10 g to 17 g. . The average particle diameter of the obtained composite fine particles was 34.0 nm, and the ratio of inorganic core particles / organic polymer was 50/50.
A coating composition was prepared and a hard coat layer was formed in the same manner as in Example 1 except that this dispersion (S-8) was used. This hard coat layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

A silicon-containing polymer (P-3) was obtained in the same manner as in Reference Example 2, except that the amount of butyl acrylate used was changed from 112 g to 62 g, and the amount of 2-hydroxyethyl methacrylate used was changed from 187 g to 237 g. This silicon-containing polymer (P-3) had a number average molecular weight of 14,000 and a weight average molecular weight of 29,000. Similar to Reference Example 3, except that this silicon-containing polymer (P-3) was used and the amount of acryloxyethyl isocyanate used was changed from 142 g to 159 g, the unsaturated group-containing silicon-containing polymer (P -4) was dissolved in butyl acetate. A composite fine particle dispersion (S-9) was obtained in the same manner as in Example 1 except that this unsaturated group-containing silicon-containing polymer (P-4) was used. The average particle diameter of the obtained composite fine particles was 32.0 nm, and the ratio of inorganic core particles / organic polymer was 61/39.
A coating composition was prepared and a hard coat layer was formed in the same manner as in Example 1 except that this dispersion (S-9) was used. This hard coat layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

A silicon-containing polymer (P-5) was obtained in the same manner as in Reference Example 2 except that the amount of butyl acrylate used was changed from 112 g to 149 g and the amount of 2-hydroxyethyl methacrylate used was changed from 187 g to 150 g. This silicon-containing polymer (P-5) had a number average molecular weight of 10,000 and a weight average molecular weight of 22,000. Similar to Reference Example 3, except that this silicon-containing polymer (P-5) was used and the amount of acryloxyethyl isocyanate used was changed from 142 g to 100 g, the unsaturated group-containing silicon-containing polymer (P A solution in which -6) was dissolved in butyl acetate was obtained. A composite fine particle dispersion (S-10) was obtained in the same manner as in Example 1 except that this unsaturated group-containing silicon-containing polymer (P-6) was used. The average particle diameter of the obtained composite fine particles was 18.6 nm, and the ratio of inorganic core particles / organic polymer was 61/39.
A coating composition was prepared and a hard coat layer was formed in the same manner as in Example 1 except that this dispersion (S-10) was used. This hard coat layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

A silicon-containing polymer (P-7) was obtained in the same manner as in Reference Example 2, except that the amount of 2,2′-azobis (2-methylbutyronitrile) used was changed from 2.5 g to 1.8 g. . This silicon-containing polymer (P-7) had a number average molecular weight of 23,000 and a weight average molecular weight of 39,000. A solution in which the unsaturated group-containing silicon-containing polymer (P-8) was dissolved in butyl acetate was obtained in the same manner as in Reference Example 3 except that this silicon-containing polymer (P-7) was used. A composite fine particle dispersion (S-11) was obtained in the same manner as in Example 1 except that this unsaturated group-containing silicon-containing polymer (P-8) was used. The average particle diameter of the obtained composite fine particles was 30.5 nm, and the ratio of inorganic core particles / organic polymer was 61/39.
A coating composition was prepared and a hard coat layer was formed in the same manner as in Example 1 except that this dispersion (S-11) was used. This hard coat layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

A silicon-containing polymer (P-9) was obtained in the same manner as in Reference Example 2, except that the amount of 2,2′-azobis (2-methylbutyronitrile) used was changed from 2.5 g to 3.5 g. . This silicon-containing polymer (P-9) had a number average molecular weight of 6,000 and a weight average molecular weight of 15,000. A solution in which the unsaturated group-containing silicon-containing polymer (P-10) was dissolved in butyl acetate was obtained in the same manner as in Reference Example 3 except that this silicon-containing polymer (P-9) was used. A composite fine particle dispersion (S-12) was obtained in the same manner as in Example 1 except that this unsaturated group-containing silicon-containing polymer (P-10) was used. The average particle diameter of the obtained composite fine particles was 17.4 nm, and the ratio of inorganic core particles / organic polymer was 61/39.
A coating composition was prepared and a hard coat layer was formed in the same manner as in Example 1 except that this dispersion (S-12) was used. This hard coat layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

  A solution in which 15 g of dipentaerythritol hexaacrylate was dissolved in 22 g of methyl ethyl ketone, a solution in which 1.4 g of a photopolymerization initiator (Irgacure 907) was dissolved in 16 g of methyl ethyl ketone, and 50 g of the composite fine particle dispersion (S-1) were mixed. A coating composition was prepared to form a hard coat layer. This hard coat layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

  A coating composition was prepared in the same manner as in Example 1 except that urethane acrylate (DPHA-40H, manufactured by Nippon Kayaku Co., Ltd.) was used instead of dipentaerythritol hexaacrylate, and a hard coating was prepared. A layer was formed. This hard coat layer was subjected to the same evaluation as in Example 1. The results are shown in Table 2.

(Synthesis of silicon-containing polymer (P-11))
Into a 1 liter flask equipped with a stirrer, dripping port, thermometer, cooling pipe and nitrogen gas inlet port, 260 g of butyl acetate as an organic solvent was introduced, nitrogen gas was introduced, and the flask internal temperature was heated to 95 ° C. while stirring. did. Next, 15 g of the above polymerizable polysiloxane (M-1), 140 g of butyl acrylate, 84 g of 2-hydroxyethyl methacrylate, 60 g of perfluorooctyl ethyl methacrylate, 2.5 g of 2,2′-azobis (2-methylbutyronitrile) The mixed solution was dropped from the dropping port over 3 hours. After the dropwise addition, stirring was continued for 1 hour at the same temperature. Then, 0.2 g of 2,2′-azobis (2-methylbutyronitrile) was added to the reaction mixture twice every 30 minutes, and the reaction mixture was further added for 2 hours. Copolymerization was conducted by heating to obtain a solution in which a silicon-containing polymer (P-11) having a number average molecular weight of 12,000 and a weight average molecular weight of 27,000 was dissolved in butyl acetate. The solid content of the obtained solution was 48.5%.

(Synthesis of unsaturated group-containing silicon-containing polymer (P-12))
Into a 1 liter flask equipped with a stirrer, a dripping port, a thermometer, a cooling pipe and a nitrogen gas introduction port, 400 g of silicon-containing polymer (P-11) was introduced, nitrogen gas was introduced, and the flask internal temperature was increased to 70 with stirring. Heated to ° C. Next, 18 mg of dibutyltin laurate was added to the flask, and then a butyl acetate solution of 59 g of acryloxyethyl isocyanate (Karenz AOI, Showa Denko KK) was added dropwise over 1 hour with stirring. After completion of the dropwise addition, stirring was continued for 6 hours at the same temperature to advance the reaction. After the reaction, methanol was added to the system to adjust the solid content to 45% to obtain a solution in which the unsaturated group-containing silicon-containing polymer (P-12) was dissolved in butyl acetate.

(Preparation of composite fine particle dispersion)
200 g of butyl acetate and 50 g of methanol were charged into a 500 ml four-necked flask equipped with a stirrer, two dropping ports (dropping port a and dropping port b), and a thermometer, and the internal temperature was adjusted to 40 ° C. Next, while stirring the flask, 10 g of a butyl acetate solution of unsaturated group-containing silicon-containing polymer (P-12), 13 g of tetramethoxysilane and 5 g of butyl acetate (raw material liquid A) were added from the dropping port a to 25 A mixed liquid (raw material liquid B) of 2 g of aqueous ammonia, 15 g of methanol and 5 g of deionized water was dropped from the dropping port b over 2 hours. After dropping, a distillation column, a cooling tube connected to the distillation column and an outlet are provided instead of the cooling tube, and the temperature inside the flask is raised to 70 ° C. under a pressure of 40 kPa. The mixture was distilled off to 30% to obtain a dispersion (S-13) in which composite fine particles were dispersed in butyl acetate. The average particle diameter of the obtained composite fine particles was 15.5 nm, and the ratio of inorganic core particles / organic polymer was 61/39.

(Preparation and Evaluation of Low Refractive Index Coating Composition)
A solution in which 7 g of dipentaerythritol hexaacrylate (DPE-6A, manufactured by Kyoeisha Chemical Co., Ltd.) is dissolved in 20 g of methyl ethyl ketone, a solution of 1 g of photopolymerization initiator (Irgacure 907, manufactured by Ciba Specialty Chemicals) in 8 g of methyl ethyl ketone, and a composite 50 g of the fine particle dispersion (S-13) was mixed to prepare a low refractive index coating composition. The formulation of the composition is shown in Table 3 below together with the formulation of the compositions of Examples 13 to 17 and Comparative Examples 4 to 5 described later.

A solution in which 7 g of dipentaerythritol hexaacrylate was dissolved in 14 g of methyl ethyl ketone and a solution in which 0.3 g of a photopolymerization initiator (Irgacure 907) was dissolved in 3 g of methyl ethyl ketone were mixed to prepare a coating composition. This coating composition was applied to a polyethylene terephthalate (PET) film (Cosmo Shine A4300, manufactured by Toyobo Co., Ltd .: thickness 188 μm) in the same manner as in Example 1 to form a hard coat layer. The low refractive index coating composition was applied to the hard coat layer side of the PET film / hard coat layer laminate using a bar coater. The coating layer was dried at 100 ° C. for 15 minutes and then cured by irradiating ultraviolet rays of 750 mJ / cm ² with a high pressure mercury lamp to form a low refractive index layer having a thickness of about 100 nm. The film thickness was adjusted between 90 and 120 nm so that the reflectance spectrum at a wavelength between 400 nm and 800 nm was minimized at a wavelength of 550 nm. The obtained low refractive index layer was evaluated for refractive index, luminous reflectance, haze, total light transmittance, steel wool resistance and pencil hardness. The evaluation results are shown in Table 4 together with the results of Examples 13 to 17 and Comparative Examples 4 to 5 described later.

  A low refractive index coating composition was prepared in the same manner as in Example 12 except that (S-1) was used instead of the composite fine particle dispersion (S-13). A low refractive index layer was formed in the same manner as in Example 12 except that this low refractive index coating composition was used. The obtained low refractive index layer was subjected to the same evaluation as in Example 12. The results are shown in Table 4.

(Comparative Example 4)
A composite fine particle dispersion (S-14) was obtained in the same manner as in Example 12 except that the silicon-containing polymer (P-11) was used instead of the unsaturated group-containing silicon-containing polymer (P-12). A low refractive index layer was formed in the same manner as in Example 12 except that the composite fine particle dispersion (S-14) was used. The obtained low refractive index layer was subjected to the same evaluation as in Example 12. The results are shown in Table 4.

(Comparative Example 5)
A low refractive index layer was formed in the same manner as in Example 12 except that the composite fine particle dispersion (S-4) was used. The obtained low refractive index layer was subjected to the same evaluation as in Example 12. The results are shown in Table 4.

  A silicon-containing polymer was obtained in the same manner as in Example 12 except that the amount of butyl acrylate used was changed from 140 g to 50 g, and that the amount of perfluorooctylethyl methacrylate was changed from 60 g to 150 g. This silicon-containing polymer had a number average molecular weight of 14,000 and a weight average molecular weight of 28,000. A composite fine particle dispersion (S-15) was obtained in the same manner as in Example 12 except that this silicon-containing polymer was used. A low refractive index layer was formed in the same manner as in Example 12 except that the composite fine particle dispersion (S-15) was used. The obtained low refractive index layer was subjected to the same evaluation as in Example 12. The results are shown in Table 4.

  A silicon-containing polymer was obtained in the same manner as in Example 12 except that butyl acrylate was not used and the amount of perfluorooctylethyl methacrylate was changed from 60 g to 200 g. This silicon-containing polymer had a number average molecular weight of 13,000 and a weight average molecular weight of 27,000. A composite fine particle dispersion (S-16) was obtained in the same manner as in Example 12 except that this silicon-containing polymer was used. A low refractive index layer was formed in the same manner as in Example 12 except that the composite fine particle dispersion (S-16) was used. The obtained low refractive index layer was subjected to the same evaluation as in Example 12. The results are shown in Table 4.

  A silicon-containing polymer was obtained in the same manner as in Example 12, except that the amount of butyl acrylate used was changed from 140 g to 80 g, and the amount of 2-hydroxyethyl methacrylate used was changed from 84 g to 204 g. This silicon-containing polymer had a number average molecular weight of 15,000 and a weight average molecular weight of 29,000. Using this silicon-containing polymer, an unsaturated group-containing silicon-containing polymer was obtained in the same manner as in Example 12 except that the amount of acryloxyethyl isocyanate used was changed from 59 g to 201 g. A composite fine particle dispersion (S-17) was obtained in the same manner as in Example 12 except that this unsaturated group-containing silicon-containing polymer was used. A low refractive index layer was formed in the same manner as in Example 12 except that the composite fine particle dispersion (S-17) was used. The obtained low refractive index layer was subjected to the same evaluation as in Example 12. The results are shown in Table 4.

  A low refractive index coating composition was prepared in the same manner as in Example 12 except that urethane acrylate (DPHA-40H, manufactured by Nippon Kayaku Co., Ltd.) was used instead of dipentaerythritol hexaacrylate, and the formulation shown in Table 3 was used. . A low refractive index layer was formed in the same manner as in Example 12 except that this low refractive index coating composition was used. The obtained low refractive index layer was subjected to the same evaluation as in Example 12. The results are shown in Table 4.

(Evaluation)
As is apparent from Table 2, the hard coat layer obtained using the composite fine particles of the present invention is excellent in the balance of hardness, scratch resistance and appearance (unevenness, haze, light transmittance). Further, as is apparent from Table 4, the low refractive index layer obtained using the composite fine particles of the present invention achieves a good low refractive index and is excellent in the balance of hardness, reflectance and transmittance. Furthermore, the composite fine particles of the present invention are excellent in dispersion stability because they do not cause aggregation in the state of dispersion, in addition to obtaining a coating film having excellent properties as described above.

The composite fine particles and coating composition of the present invention are a transfer foil film, a plastic optical component, a touch panel, a film type liquid crystal element, a hard coating agent such as a plastic molding, a low refractive index coating agent for an antireflection film, and a coating for a light diffusion film. It can be suitably used as an agent.

Claims (16)

Having an inorganic core particle and an organic polymer bonded to at least a part of the surface of the core particle;
Composite fine particles in which the organic polymer has a polymerizable functional group in its side chain.   The composite fine particle according to claim 1, wherein the polymerizable functional group is bonded to the organic polymer main chain via a urethane bond.   The composite fine particle according to claim 1 or 2, wherein the polymerizable functional group is an ethylenically unsaturated group.   The composite fine particle according to any one of claims 1 to 3, wherein the organic polymer is an acrylic polymer. Reacting a silicon-containing polymer having a functional group having active hydrogen and a polysiloxane group in the side chain with an isocyanate compound having a polymerizable functional group;
Reacting the reaction product with a metal compound capable of generating a metal oxide by hydrolysis.   The production method according to claim 5, wherein the polymerizable functional group is an ethylenically unsaturated group.   The production method according to claim 5 or 6, wherein the silicon-containing polymer is an acrylic polymer.   A coating composition comprising the composite fine particles according to claim 1 and a polyfunctional polymerizable compound.   The coating composition according to claim 8, further comprising a polymerization initiator and a solvent.   An optical film comprising a coating layer of the coating composition according to claim 8.   A low refractive index coating composition comprising the composite fine particles according to claim 1 and a polyfunctional polymerizable compound, wherein the organic polymer in the composite fine particles has a portion containing a fluorine atom.   The low refractive index coating composition according to claim 11, further comprising a polymerization initiator and a solvent.   An antireflection film comprising an application layer of the low refractive index coating composition according to claim 11.   A polarizing plate comprising a polarizer and the antireflection film according to claim 13.   An optical filter for plasma display, comprising a support and the antireflection film according to claim 13.   An image display device comprising at least one selected from the antireflection film according to claim 13, the polarizing plate according to claim 14, and the optical filter according to claim 15.