JP2008081618A - Acrylic resin composition having filler dispersed therein, its manufacturing method, and transparent resin molded item having surface coated with composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-coating material that exhibits excellent adhesion to a substrate resin even when applied for one layer coating as well as excellent abrasion resistance and weather resistance, and a transparent resin molded item having its surface coated that can be used as plastic glass for automobiles. <P>SOLUTION: The acrylic resin composition 20 having a filler dispersed therein comprises (A) a methoxy group-bearing silane-modified acrylic resin 12, obtained by an epoxy ring-opening esterification reaction of a carboxy group-bearing acrylic polymer (1) with a glycidyl ether group-bearing methoxysilane partial condensate (2) obtained by a demethanolation reaction of glycidol with a methoxysilane partial condensate, (B) a methoxysilane partial condensate 14, (C) a solvent and (D) a finely dispersed silica filler 10. The transparent resin molded item has its surface coated with a cured film derived from the resin composition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a filler-dispersed acrylic resin composition and a method for producing the same, a transparent resin molded body whose surface is coated with the composition, and particularly a filler dispersion capable of forming a coating film having excellent adhesion and wear resistance. The present invention relates to an acrylic resin composition, a method for producing the same, and a transparent resin molded body whose surface is coated with the composition.

  In recent years, for example, polycarbonate resin is excellent in transparency, impact resistance, lightness, workability, dimensional stability at the time of molding, etc., so it is inorganic for various applications such as mechanical parts, electronic insulating materials, and automobile parts. It has been used as an alternative to glass. On the other hand, the polycarbonate resin itself is slightly inferior in solvent resistance, wear resistance and weather resistance. For this reason, for example, when used outdoors for a long time, the deterioration proceeds, so that the physical properties and appearance may be impaired.

  On the other hand, polycarbonate resin is excellent in transparency, impact resistance, light weight, workability, dimensional stability at the time of molding, etc. as described above. There is a movement to use polycarbonate resin moldings for glass. However, in this application, since it is premised on the use of a wiper and the window itself being raised and lowered, very excellent wear resistance is required. Further, since it is assumed that the environment is exposed to severe use environment, particularly high temperature environment and continuous direct sunlight, high weather resistance similar to that of inorganic glass is required.

  In order to satisfy these requirements, an acrylic primer layer is formed on the polycarbonate resin surface, and then a hard coat layer obtained by thermally curing colloidal silica and trialkoxysilane hydrolysis condensate is sequentially laminated thereon, and further, these two layers. There has been proposed a method of imparting wear resistance by performing coating under specific heat curing conditions (for example, Patent Document 1). However, since the two-layer coat is required, the production work becomes complicated and the cost may increase.

  Therefore, in Patent Document 2, a carboxy group-containing acrylic polymer (1) and a glycidyl ether group-containing methoxysilane partial condensate (2) obtained by a demethanol reaction of glycidol and a methoxysilane partial condensate are combined with an epoxy. A coating composition comprising an acrylic resin composition containing a methoxy group-containing silane-modified acrylic resin obtained by a ring-opening esterification reaction and a medium is proposed, and this coating composition coats one layer on a polycarbonate resin surface. This is a type of siloxane hard coat agent.

Japanese Patent Laid-Open No. 2004-27110 JP 2004-300238 A

  However, even the above-mentioned type of siloxane-based hard coating agent that coats one layer has a problem that sufficient adhesion to a polycarbonate resin, which has been increasingly demanded in recent years, cannot be obtained.

  The present invention has been made in view of the above problems, does not require a conventional primer, has excellent adhesion to a base resin (for example, polycarbonate resin) even with a single layer coat, and has wear resistance and weather resistance. And a transparent resin molded body coated with a surface usable as an automotive plastic glass.

  The filler-dispersed acrylic resin composition of the present invention, a method for producing the same, and a transparent resin molded body whose surface is coated with the composition have the following characteristics.

  (1) (A) A carboxy group-containing acrylic polymer (1) and a glycidyl ether group-containing methoxysilane partial condensate (2) obtained by a demethanol reaction of glycidol and a methoxysilane partial condensate are epoxy ring-opened. A filler-dispersed acrylic resin composition comprising an esterified methoxy group-containing silane-modified acrylic resin, (B) a methoxysilane partial condensate, (C) a solvent, and (D) a finely dispersed silica filler. It is a thing.

  By the presence of the (B) methoxysilane partial condensate, aggregation of the (A) methoxy group-containing silane-modified acrylic resin and (D) silica filler can be suppressed. As a result, the (A) methoxy In the mixture of the group-containing silane-modified acrylic resin, the (B) methoxysilane partial condensate, and the (C) solvent, a composition in which the (D) silica filler is ultrafinely dispersed can be obtained. Thereby, a hard coat layer having sufficient wear resistance even in a single layer coat and having sufficient adhesion with a base resin (for example, polycarbonate resin) mainly by the (A) methoxy group-containing silane-modified acrylic resin. Can be provided on the base resin.

  (2) In the filler-dispersed acrylic resin composition described in (1) above, the carboxy group-containing acrylic polymer (1) has an alkyl (meth) acrylate having an alkyl group having 1 to 2 carbon atoms, and the number of carbon atoms. It is a copolymer of monomer components containing an alkyl (meth) acrylate having 3 to 22 alkyl groups and an ethylenically unsaturated carboxylic acid.

  By the above combination, sufficient adhesion with the base resin can be ensured.

  (3) In the filler-dispersed acrylic resin composition according to the above (1) or (2), the silica filler is dispersed in an ultrafine dispersion state using a disperser that operates a strong shearing force.

  Particularly, the hard coat layer formed by applying the composition in which the silica filler is dispersed in the ultrafine dispersion state on the surface of the base resin using the disperser with the strong shearing force is improved in wear resistance.

  (4) Demethanol of (A) carboxy group-containing acrylic polymer (1), glycidol and methoxysilane partial condensate under the condition that the haze value measured at a coating cured film thickness of 10 μm is 1.5% or less. A methoxy group-containing silane-modified acrylic resin obtained by subjecting a glycidyl ether group-containing methoxysilane partial condensate (2) obtained by the reaction to an epoxy ring-opening esterification reaction, (B) a methoxysilane partial condensate, and (C) This is a method for producing a filler-dispersed acrylic resin composition in which a silica filler is ultrafinely dispersed in a mixed liquid comprising a solvent.

  The haze (also referred to as haze) is also referred to as a haze value, and represents a haze level and a light diffusion level. For example, when applied to a transparent base resin, it is necessary to have a haze that does not impair the transparency of the base resin. Under the above conditions, the base coated with the filler-dispersed acrylic resin composition is coated. A transparent resin molding can be obtained without impairing the transparency of the material resin itself.

  (5) A transparent resin molded body having a surface coated with a cured film of the filler-dispersed acrylic resin composition according to any one of (1) to (3).

  The cured film of the filler-dispersed acrylic resin composition has excellent adhesion to the resin substrate, excellent wear resistance, and finely dispersed silica filler. Therefore, the haze value is low and the transparency is high. It is a cured film. Therefore, the transparency of the base resin whose surface is coated with the cured film is not impaired, and the obtained resin molding is also transparent.

  (6) In the transparent resin molded product according to (5), the transparent resin molded product is plastic glass for automobiles.

  Since it is a transparent resin molded body with excellent wear resistance and a hard coat layer formed, this transparent resin molded body is particularly suitable for plastic glass for automobiles that wear due to the use of wipers or raising and lowering of windows.

  According to the present invention, a conventional primer is not required, and the composition is applied and heat-cured, so that even a single-layer coat has excellent adhesion to a base resin (for example, polycarbonate resin) and wear resistance. Surface coating composition excellent in heat resistance and weather resistance, and a surface-coated transparent resin molding usable as plastic glass for automobiles can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Filler-dispersed acrylic resin composition]
The filler-dispersed acrylic resin composition of the present embodiment includes (A) a glycidyl ether group-containing methoxysilane portion obtained by a demethanol reaction of carboxy group-containing acrylic polymer (1), glycidol and a methoxysilane partial condensate. A methoxy group-containing silane-modified acrylic resin obtained by subjecting the condensate (2) to an epoxy ring-opening esterification reaction, (B) a methoxysilane partial condensate, (C) a solvent, and (D) a finely dispersed silica. And a filler.

-Methoxy group-containing silane-modified acrylic resin (A)-
<Carboxy group-containing acrylic polymer (1)>
The carboxy group-containing acrylic polymer (1) constituting the methoxy group-containing silane-modified acrylic resin (A) comprises a monomer having a carboxyl group and other monomers, and at least one of these monomers is an acrylic monomer. A copolymer of a certain monomer component may be used, and the type of these monomers and the use amount thereof are not particularly limited.

More specifically, the carboxy group-containing acrylic polymer (1) includes an alkyl (meth) acrylate having an alkyl group having ₁ to ₂ carbon atoms (hereinafter also referred to as “C _{1 to} C ₂ ”), and 3 carbon atoms. It is a copolymer of monomer components containing an alkyl (meth) acrylate having an alkyl group of ˜22 (hereinafter also referred to as “C ₃ -C ₂₂ ”) and an ethylenically unsaturated carboxylic acid.

Examples of the alkyl (meth) acrylate having the C ₁ -C ₂ alkyl group include methyl (meth) acrylate and ethyl (meth) acrylate.

Examples of the alkyl (meth) acrylate having an alkyl group of C _{3 to} C ₂₂ include n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) ) acrylate, t- butyl (meth) acrylate, aliphatic alkyl (meth) acrylate having an alkyl group of C ₃ -C _22, such as cyclohexyl (meth) acrylate to 2-ethyl; cyclohexyl (meth) acrylate, dicyclopentenyl ( And (meth) acrylate.

The alkyl (meth) acrylate having a C ₁ -C ₂ alkyl group and the alkyl (meth) acrylate having a C ₃ -C ₂₂ alkyl group are used in a range of a molar ratio of the former / the latter from 0.2 to 2.0. Is preferably used. If the use molar ratio is less than 0.2, the wear resistance of the cured film obtained by applying the filler-dispersed acrylic resin composition to the base resin surface and thermally curing is not sufficient, while the use molar ratio is When the value exceeds 2.0, the cured film tends to be brittle and easily cracked.

  Examples of the ethylenically unsaturated carboxylic acid include (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid and the like. The use ratio of the ethylenically unsaturated carboxylic acid is preferably adjusted so that the acid value of the carboxyl group-containing acrylic polymer (1) is 10 to 150 mgKOH / g. When the acid value exceeds 150 mgKOH / g, the water resistance of the cured film is lowered. On the other hand, when the acid value is less than 10 mgKOH / g, the dispersibility of the silica filler in the cured film is deteriorated, so the ratio of the silica filler is lowered. Thus, the effects of the present invention described above cannot be obtained.

  In the carboxyl group-containing acrylic polymer (1) of the present embodiment, constituent monomers other than those described above can be used without any particular limitation without departing from the object of the present invention. Examples of the optional monomer include styrene, methylstyrene, acrylonitrile, and butadiene. The usage-amount of the said arbitrary monomer is usually less than 30 weight% among the total monomers used for a carboxyl group-containing acrylic polymer (1).

  The carboxyl group-containing acrylic polymer (1) is produced by copolymerizing the above monomer components using a conventionally known polymerization method. Specifically, a solution polymerization method using a radical polymerization initiator such as a peroxide such as benzoyl peroxide or an azobis compound such as 2,2′-azobisisobutyronitrile and an organic solvent may be used. The polymerization temperature and the polymerization time are not particularly limited, and are appropriately determined depending on the radical generation temperature and half-life of the initiator used. As the organic solvent, the carboxyl group-containing acrylic polymer (1) to be produced is dissolved and has a boiling point higher than the polymerization temperature. The carboxyl group-containing acrylic polymer (1) and a glycidyl ether group-containing methoxysilane described later If it is a non-reactive thing with respect to a partial condensate (2), it will not be specifically limited, It can use. Examples of the organic solvent include ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; aromatic solvents such as toluene and xylene, cellosolve acetate, dimethyl diglycol, and the like. Cellosolve solvents; alcohol solvents such as methanol, ethanol, isopropyl alcohol and the like can be mentioned, and these can be used alone or in combination.

  The molecular weight of the carboxyl group-containing acrylic polymer (1) is not particularly limited, but usually the number average molecular weight is preferably about 5,000 to 200,000. If the number average molecular weight is less than 5,000, the properties of the cured film described above (for example, adhesion to the base resin) are insufficient, and if it exceeds 200,000, the solution viscosity of the polymer becomes too high. This is not preferable because the coating efficiency and handling properties deteriorate.

<Glycidyl ether group-containing methoxysilane partial condensate (2)>
The glycidyl ether group-containing methoxysilane partial condensate (2) used in the present embodiment is obtained by subjecting glycidol and a methoxysilane partial condensate to a demethanol reaction.

As the methoxysilane partial condensate, the general formula R _m Si (OCH ₃ ) _4-m
(Wherein m represents an integer of 0 or 1 and R represents an alkyl group or aryl group having 8 or less carbon atoms), a hydrolyzable methoxysilane monomer represented by an acid or base catalyst, and the presence of a mistake A product obtained by hydrolysis and partial condensation is used below.

  Examples of the hydrolyzable methoxysilane monomer used as a raw material include tetramethoxysilanes such as tetramethoxysilane, methyltrimethoxysilane, and ethyltrimethoxysilane. Usually, among these, since the reactivity with glycidol is particularly high, the methoxysilane partial condensate is preferably synthesized using 70% or more of tetramethoxysilane or methylmethoxysilane. When two or more of these examples are used in combination, it is preferable to use 70% or more of tetramethoxysilane partial condensate or methylmethoxysilane partial condensate in the total amount of methoxysilane partial condensate.

  The number average molecular weight of the methoxysilane partial condensate is preferably 230 to 2,000, and the average number of Si in one molecule is preferably about 2 to 11. When the average number of Si is less than 2, the amount of methoxysilanes flowing out of the system together with alcohol increases without reacting during the demethanol reaction with glycidol, and the average number of Si exceeds 11. And the reactivity of the glycidyl ether group-containing methoxysilane partial condensate (2) with the carboxyl group-containing acrylic polymer (1) is reduced, and the desired methoxy group-containing silane-modified acrylic resin (A) is hardly obtained.

  The glycidyl ether group-containing methoxysilane partial condensate (2) can be obtained by subjecting glycidol and a methoxysilane partial condensate to a demethanol reaction. The proportion of glycidol and methoxysilane partial condensate used is not particularly limited as long as the methoxy group substantially remains, but the glycidyl group in the resulting glycidyl ether group-containing methoxysilane partial condensate (2). The methoxysilane partial condensate (2) and the glycidol are usually charged at a ratio of the glycidol hydroxyl group equivalent / methoxysilane partial condensate methoxy group equivalent = 0.01 / 1 to 0.5 / 1. Is preferably subjected to demethanol reaction. If the charging ratio is small, the proportion of the methoxysilane partial condensate that does not react with glycidol increases, and the cured product of the resin composition obtained by self-condensation of this methoxysilane partial condensate tends to become opaque, More preferably, the charging ratio is equivalent to the hydroxyl group equivalent of glycidol / the methoxy group equivalent of the methoxysilane partial condensate = 0.03 / 1 or more. Further, when the charging ratio is increased, the glycidyl group of the glycidyl ether group-containing methoxysilane partial condensate (2) becomes polycyclic and easily gels during synthesis of the methoxy group-containing silane-modified acrylic resin (A). More preferably, the charging ratio is equivalent to the hydroxyl group equivalent of glycidol / the methoxy group equivalent of the methoxysilane partial condensate = 0.4 / 1 or less.

  In the reaction of the methoxysilane partial condensate and glycidol, for example, the above components are charged, and methanol is removed while distilling off the methanol produced by heating. The reaction temperature is about 50 to 150 ° C., preferably 70 to 110 ° C., and the total reaction time is about 1 to 15 hours. In addition, when the methanol removal reaction is performed at a temperature exceeding 110 ° C., the molecular weight of the reaction product increases excessively with the condensation of methoxysilane in the reaction system, which tends to increase the viscosity or gel. In such a case, high viscosity or gelation can be prevented by a method such as stopping the methanol removal reaction.

  In addition, in the demethanol reaction of the methoxysilane partial condensate and glycidol, a conventionally known ester-hydroxyl ester transesterification catalyst that does not open an epoxy ring can be used to promote the reaction. . For example, metals such as lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, strontium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, arsenic, cerium, boron, cadmium, manganese, , These oxides, organic acid salts, halogen compounds, methoxides and the like. Among these, organic tin and organic acid tin are particularly preferable, and specifically, dibutyltin dilaurate, tin octylate and the like are effective.

  Moreover, the said reaction can be performed in a solvent. The solvent is not particularly limited as long as it dissolves the methoxysilane partial condensate and glycidol and is inert to the glycidyl group of glycidol. As such an organic solvent, for example, it is preferable to use a solvent such as toluene, xylene, or methyl ethyl ketone.

<Production of methoxy group-containing silane-modified acrylic resin (A)>
The methoxy group-containing silane-modified acrylic resin (A), which is an essential component of the composition of the present embodiment, is obtained by epoxy-opening the carboxyl group-containing acrylic polymer (1) and the glycidyl ether group-containing methoxysilane partial condensate (2). Obtained by a ring esterification reaction. The use ratio of the carboxyl group-containing acrylic polymer (1) and the glycidyl ether group-containing methoxysilane partial condensate (2) is not particularly limited, but the equivalent of the glycidyl group of the glycidyl ether group-containing methoxysilane partial condensate (2) ) / (Equivalent of carboxyl group of carboxyl group-containing acrylic polymer (1)) is preferably in the range of 0.5-10. If this equivalent ratio is less than 0.5, the effect of the present invention (for example, adhesion to the base resin) is difficult to obtain, and if the equivalent ratio exceeds 10, the cured film may become opaque. It is not preferable.

  The methoxy group-containing silane-modified acrylic resin (A) is produced, for example, by charging each of the components and heating it in a substantially anhydrous state. The main purpose of this reaction is to react the carboxyl group of the carboxyl group-containing acrylic polymer (1) with the glycidyl group of the glycidyl ether group-containing methoxysilane partial condensate (2). During this reaction, the glycidyl ether group-containing methoxysilane It is necessary to suppress the formation of silica due to the sol-gel reaction at the methoxysilyl site of the partial condensate (2). Therefore, the reaction temperature is about 50 to 120 ° C., preferably 60 to 100 ° C., and the total reaction time is preferably about 1 to 30 hours.

  In the epoxy ring-opening esterification reaction, a catalyst used for reacting a conventionally known glycidyl group with a carboxyl group can be used to promote the reaction. Examples of such catalysts include tertiary amines such as triethylamine, benzyldimethylamine, and triethanolamine; imidazoles such as 2-methylimidazole, 2-phenylimidazole, and 2-phenyl-4-methylimidazole; tributylphosphine, methyl And organic phosphines such as diphenylphosphine and triphenylphosphine. The reaction catalyst is preferably used in a proportion of 0.01 to 5 parts by weight with respect to 100 parts by weight of the solid content of the carboxyl group-containing acrylic polymer (1).

  In addition, it is preferable to perform the said reaction in an organic solvent. The organic solvent is not particularly limited as long as it is a solvent that dissolves the carboxyl group-containing acrylic polymer (1) and the glycidyl ether group-containing methoxysilane partial condensate (2). Examples of such a solvent include those used in the production of the carboxyl group-containing acrylic polymer (1).

  The methoxy group-containing silane-modified acrylic resin (A) thus obtained has a methoxy group derived from the methoxysilane partial condensate (2) in the molecule. Although the content of the methoxy group is not particularly limited, the methoxy group is a cured product bonded to each other by sol-gel reaction or demethanol condensation by evaporation of a solvent, heat treatment, or reaction with moisture (humidity). Since it is necessary to form the methoxy group-containing silane-modified acrylic resin (A), usually 50 to 95 mol%, preferably 60 to 90 mol% of the methoxy group of the methoxysilane partial condensate remains unreacted. It is good to keep.

-Methoxysilane partial condensate (B)-
As described above, the methoxysilane partial condensate has the general formula R _m Si (OCH ₃ ) _4-m
(Wherein m represents an integer of 0 or 1 and R represents an alkyl group or aryl group having 8 or less carbon atoms), a hydrolyzable methoxysilane monomer represented by an acid or base catalyst, and the presence of a mistake A product obtained by hydrolysis and partial condensation is used below.

  Further, as described above, examples of the hydrolyzable methoxysilane monomer as a raw material include tetra- or trimethoxysilanes such as tetramethoxysilane, methyltrimethoxysilane, and ethyltrimethoxysilane. When two or more of these examples are used in combination, it is preferable to use 70% or more of tetramethoxysilane partial condensate or methylmethoxysilane partial condensate in the total amount of methoxysilane partial condensate.

  The number average molecular weight of the methoxysilane partial condensate is preferably 230 to 2000, and the average number of Si in one molecule is preferably about 2 to 11. When the molecular weight increases, the viscosity increases. When the molecular weight exceeds 2000, blending and dispersion become difficult, which is not preferable.

-Silica filler (D)-
The silica filler used in the present embodiment is preferably a nanosilica filler, and the production method is not particularly limited, but the average particle diameter is preferably 50 nm or less. If the average particle diameter exceeds 50 nm, it is not preferable because the transparency of the cured film is impaired even if an ultrafine dispersion state is obtained.

-Solvent (C)-
Specific examples of the solvent include, for example, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; aromatic solvents such as toluene and xylene; cellosolve acetate, dimethyl diglycol And cellosolve solvents such as alcohol solvents such as methanol, ethanol and isopropyl alcohol. These can be used alone or in combination.

-Composition-
The composition of the liquid methoxy group-containing silane-modified acrylic resin (A), methoxysilane partial condensate (B), solvent (C) and finely dispersed silica filler (D) is not particularly limited, It is set in consideration of the physical properties of the cured film, the stability as the composition, the handleability, and the like. The silica filler component of the present embodiment is 0.5 to 20% by weight, preferably 1 to 10% by weight of the total solids, and if too much, dispersion becomes difficult, and transparency and wear resistance are reduced. It is not preferable.

  The methoxysilane partial condensate (B) and nanosilica filler (D) to be blended are integrated by hydrolysis and polycondensation when the methoxy group-containing silane-modified acrylic resin (A) is cured. As shown in FIG. 1, the active point on the filler surface is appropriately bonded (sol-gel reaction) with the methoxy group-containing silane-modified acrylic resin 12 and the methoxysilane partial condensate 14 so that the entire composition has a crosslinking density. Since it is expressed by relaxation and relaxation of internal stress due to curing shrinkage, when the silica filler 10 component is less than 0.5%, the adhesion to the base resin is lowered and the wear resistance tends to be lowered.

  In general, the composition of the present embodiment preferably has a solid content concentration of about 5 to 50% by weight in consideration of handleability, coating workability, and the like. The polymerization ratio between the methoxy group-containing silane-modified acrylic resin (A) and the methoxysilane partial condensate (B) is not particularly limited, taking into consideration the physical properties of the cured product, coating stability, handling workability, etc. However, it is usually in the range of 50/50 to 90/10, and preferably in the range of 60/40 to 80/20.

  The resin composition of the present embodiment may contain, as an optional component, a carboxyl group-containing acrylic polymer that is a raw material component used during the production of the methoxy group-containing silane-modified acrylic resin (A).

  When the filler-dispersed acrylic resin composition of the present embodiment is used for hard coating applications, various additives (release agents, surface treatment agents, leveling agents) are used within a range that does not impair the effects of the present invention. , Stabilizers, colorants, coupling agents, and the like).

[Method for producing filler-dispersed acrylic resin composition, method for superdispersing filler]
In the present embodiment, the aggregated silica filler nanoparticles are redispersed by the strong shearing and crushing forces of the dispersing group. Even when the silica filler is ultrafinely dispersed by such a method, as it is, aggregation occurs again due to the interaction between the fine particles. In order to exhibit transparency and abrasion resistance, it is necessary to efficiently coat the surface of the silica filler fine particles redispersed to the primary particle size of nano size by the dispersion treatment to suppress this reaggregation.

  In the present embodiment, the methoxy group-containing silane-modified acrylic resin (A) and the methoxysilane partial condensate (B) serve to suppress reaggregation of the silica filler (D) fine particles. In order to efficiently coat the surface with these substances, it is necessary that a reactive site capable of reacting with the methoxysilyl group exists on the surface of the silica filler fine particles. In general, the silica filler is subjected to a surface inactivation treatment for the purpose of suppressing aggregation. Therefore, it is necessary to select and use a filler having reactive active sites on the surface that can be reacted with the methoxy group-containing silane-modified acrylic resin and the methoxysilane partial condensate. As the filler, an unmodified silica filler is generally suitable, and specific examples include “HDKN-20” manufactured by Asahi Kasei Wacker Silicone.

  As a dispersion method, a methoxy group-containing silane-modified acrylic resin (A), a methoxysilane partial condensate (B), a silica filler (D), and a solvent (C) are mixed in advance and then dispersed by a disperser. In this case, in consideration of the handling property of the coating liquid and the physical properties of the cured film, mechanical mixing, heat treatment or the like may be performed in advance.

-Disperser-
The apparatus for carrying out the dispersion of the present embodiment is not particularly limited as long as the desired dispersion state can be finally achieved, but a ball mill, a vibration mill, a planetary pulverizer, etc. can be exemplified, and operability in particular. In consideration of productivity, it is preferable to select a ball mill. The ball material for dispersion used in this case can be used without particular limitation as long as it can achieve the desired level of ultrafine dispersion and does not consume the process, and zirconia is particularly preferred. Selected.

  In the present embodiment, selection of dispersion conditions is important in order to exhibit excellent transparency, durability and adhesion to the cured film. That is, it is necessary to achieve fine dispersion of the silica filler and to cause a reaction with the methoxy group-containing silane-modified acrylic resin (A) and the methoxysilane partial condensate (B) on the filler surface. For this reason, it is necessary to give a high shearing force to the nano silica filler.

  The dispersion conditions for achieving fine dispersion in the present embodiment are appropriately set in consideration of the properties of the composition to be dispersed, the apparatus used for dispersion, and the like. Since the ultrafine dispersion of the silica filler is achieved, the transparency of the cured film is improved. Therefore, the dispersion state of the silica filler can be determined from the light transmittance of the cured film having a specific thickness. Specifically, each condition is adjusted so that a haze value = Td / Tt (Td: scattered light transmittance / Tt: total light transmittance) at a cured film thickness of 10 μm can be 1.5% or less.

  For example, in the case of a planetary ball mill, in order to achieve a haze value of 1.5% or less at a cured film thickness of 10 μm, it is necessary to set the shearing force so that gravity of 20 G or more, preferably 25 G or more is applied. In order to achieve this condition, the number of times is set in consideration of the container, the revolution radius, the rotation / revolution ratio, and the like. Thus, sufficient dispersion is not achieved when the shear force is low, while it is not practical when the shear force is too high.

  The temperature during dispersion in the present embodiment is set in consideration of handling properties such as the dispersion state of the silica filler, the physical properties of the cured film, and the viscosity. In general, as the temperature during dispersion increases, the reaction with the methoxy group-containing silane-modified acrylic resin (A) and the methoxysilane partial condensate (B) proceeds, and the haze value of the cured film tends to decrease, It is preferable that it is the range of 30 to 80 degreeC. Below 30 ° C., it takes a long time to achieve dispersion. If the temperature exceeds 80 ° C., there is a problem such as volatilization of the solvent, which is not preferable. When there is a temperature rise due to frictional heat or the like accompanying the dispersion treatment, cooling or the like can be performed as necessary.

  The dispersion time in the present embodiment is set in consideration of handling properties such as the dispersion state of the silica filler, the physical properties of the cured film, and the viscosity. Generally, the dispersion proceeds more finely by increasing the dispersion time, and the haze value of the cured film also tends to decrease, and is preferably about 10 minutes to 150 minutes, more preferably 60 minutes to 120 minutes. It is a range. Exceeding the above range is inefficient, and heat generation due to frictional heat or the like becomes significant, causing problems such as solvent volatilization.

[Ultraviolet absorber]
In particular, in order to ensure light resistance, it is necessary to use an ultraviolet absorber. In such a case, it is necessary to add an ultraviolet absorber to the resin composition.

  As the ultraviolet absorber, an additive type and / or a reactive type can be used, and organic compounds such as benzophenone, benzotriazole, and triazine, or metal oxides such as titanium oxide, cerium oxide, and zinc oxide can be used. The organic ultraviolet absorber is preferable from the viewpoint of transparency.

  The benzophenone-based ultraviolet absorbers include “Uvinul 400” (trade name, manufactured by BASF) as 2,4-dihydroxybenzophenone, and “Sumisorb 130” (trade name, Sumitomo Chemical) as 2-hydroxy-4-octoxybenzophenone. ), 2- (2′-hydroxy-5′-methacryloxyphenyl) -2H-benzotriazole, “RUVA-93” (trade name, manufactured by Otsuka Chemical Co., Ltd.), 2,2 ′, 4,4 Examples of '-tetrahydroxybenzophenone include “Uvinul 3050” (trade name, manufactured by BASF).

  As the benzotriazole-based UV absorber, 2- (2′-hydroxy-3 ′, 5′-di-t-amylphenyl) benzotriazole, “Tinuvin 328” (trade name, manufactured by Ciba Specialty Chemicals) ), 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, “Sumisorb 200” (trade name, manufactured by Sumitomo Chemical Co., Ltd.) and the like.

  Triazine-based UV absorbers include 2- [4-[(2-hydroxy-3-didecyloxypropyl) -oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl)- 1,3,5-triazine and 2- [4-[(2-hydroxy-3-tridecyloxypropyl) -oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) Examples of the mixture of -1,3,5-triazine include “TINUVIN 400” (trade name, manufactured by Ciba Specialty Chemicals).

  These ultraviolet absorbers can be used alone or in combination of two or more. The addition amount of the ultraviolet absorber is not particularly limited, but the transmittance at a wavelength of 310 nm or less is preferably 10% or less, and the transmittance at 360 nm or less is more preferably 10% or less. For example, when the base resin is a polycarbonate resin, the deterioration dominant wavelengths of the polycarbonate resin base are 280 to 310 nm and 330 to 360 nm. The addition amount of the ultraviolet absorber satisfying the characteristics is determined by the cured film thickness, the ultraviolet absorption characteristics and stability of the ultraviolet absorber.

  Addition of an ultraviolet absorber more than necessary is not preferable because not only a further improvement in weather resistance cannot be expected, but also the adhesiveness and cured film characteristics are deteriorated.

  Moreover, it is recommended as a preferable embodiment to add a polymer type ultraviolet absorber that does not cause a problem of bleeding on the surface layer of a cured film obtained by thermally curing the filler-dispersed acrylic resin composition. The polymer type ultraviolet absorber refers to a polymer having a skeleton in the side chain effective as an ultraviolet absorber. Moreover, an acrylic polymer ultraviolet absorber is mainly preferred from the viewpoint of compatibility with the filler-dispersed acrylic resin composition. As the acrylic polymer ultraviolet absorber, for example, as an acrylic polymer having a benzotriazole skeleton in the side chain, “UVA-1635” (trade name, manufactured by BASF), an acrylic polymer having a benzophenone skeleton in the side chain, “ULS-933LP” (trade name, manufactured by Yushi Kogyo Co., Ltd.).

  In order to improve the weather resistance, it is preferable to add a hindered amine light stabilizer in a proportion of 0 to 3% by weight based on the non-volatile content of the paint as necessary. As the hindered amine-based light stabilizer, an additive type and / or a reactive type can be used, and “TINUVIN 292” (as bis (1,2,2,6,6, -pentamethyl-4-piperidyl) sebacate) can be used. "TINUVIN 123" (trade name, manufactured by Ciba Specialty Chemicals) as a trade name, manufactured by Ciba Specialty Chemicals), and bis (1-octaoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate ), 2,2,6,6-tetramethyl-4-piperidyl methacrylate, “ADEKA STAB LA-87” (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.).

-Addition method-
Usually, after the dispersion, the dispersed balls are separated and used by a method such as filtration. Thereafter, it may be diluted.

[Transparent resin molding]
-Coating method-
Thereafter, coating is performed on the surface of the resin substrate, but the coating method is not particularly limited. It can be applied using spin coating, dipping, bar coater or applicator. Since condensation curing proceeds at room temperature, it is necessary to consider the coating conditions. After coating, the filler-dispersed acrylic resin composition is heated to evaporate the solvent by drying and advance the sol-gel curing reaction, whereby the hard coating layer, which is an acrylic resin-silica hybrid cured product, is a base resin. For example, it is formed on a polycarbonate resin molded body. In the present specification, “polycarbonate” is also referred to as polycarbonate. The solvent distillation and curing conditions may be appropriately selected according to the required cured film thickness, composition composition, and the like, and are usually performed under conditions of 50 ° C to 140 ° C and 1 hour to 4 hours. If it is less than 50 ° C., drying is incomplete, and if it exceeds 140 ° C., it exceeds the heat resistance of the base resin, for example, polycarbonate resin, which is not preferable. In addition, a method of increasing the temperature after performing preliminary curing at a low temperature and curing can be arbitrarily selected in consideration of the physical properties of the cured film.

  As a plastic glass for automobiles, a transparent coating in which a hard coating layer is formed by applying the filler-dispersed acrylic resin composition of the present embodiment described above to a base material made of a polycarbonate resin, and distilling off the solvent to thermally cure. A resin molded body is preferred.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to this. In addition, the polycarbonate resin molded object coat | covered with the filler dispersion | distribution acrylic resin composition was evaluated with the following method.

(Adhesion)
Nichiban adhesive tape (trade name: cello tape (registered trademark)) was made on the coated surface of the substrate (in the examples, a substrate made of polycarbonate resin, the same applies hereinafter) with a cutter knife at 100 grids at 1 mm intervals. After pressure bonding, it was peeled off vertically and evaluated from the number of grids remaining on the substrate.

(Abrasion resistance)
A wear wheel “CS-10F” was attached to a Taber INDUSTRIES Taber abrasion tester, a Taber abrasion test was performed at a load of 500 g and 500 revolutions, and a haze difference ΔH (%) before and after the abrasion test was measured and evaluated. The measurement of haze was performed using “NDH2000” manufactured by Nippon Denshoku Industries Co., Ltd. The value obtained by subtracting the haze value of the substrate from the haze value before the Taber abrasion test is defined as the initial transparency (haze%) of the cured film (haze = Td / Tt × 100, Td: scattered light transmittance, Tt: Total light transmittance). The haze difference ΔH (%) before and after the wear test in the evaluation of wear resistance is preferably 10% or less in order to conform to the certification standard for automotive glass.

(Production example)
Composeran AC601 (Arakawa Chemical Industries, Ltd.) was used as the methoxy group-containing silane-modified acrylic resin composition.

Example 1.
A zirconia bead 13.5 mL (30 vol% of the container capacity) is put in a 45 mL zirconium container, and the composition shown by the pre-dispersion in Table 1, that is, a methoxy group-containing silane-modified acrylic resin (Arakawa Chemical Industries, Ltd.) Manufactured, trade name: Composcelan AC) and methoxysilane partial condensate (manufactured by Tama Chemical Co., Ltd., trade name: methyl silicate 51) were added. Using a planetary ball mill (P-7, manufactured by FRITSCH), this was carried out at 50 ° C. and 120 ° C. at a revolution speed of 800 rpm (revolution radius: 6.7 cm, rotation / revolution ratio = 2.0, gravity equivalent to 24.5 G). After mixing for a minute, a mixture of methoxy group-containing silane-modified acrylic resin and silica filler (product name: HDKN-20, manufactured by Asahi Kasei Silicone Co., Ltd.) was added so that the composition shown in the final composition in Table 1 was obtained. A filler-dispersed acrylic resin composition was prepared by mixing under the same dispersion conditions as the pre-dispersion and filtering out the zirconia beads.

  The prepared filler-dispersed acrylic resin composition was applied to one side of a polycarbonate resin plate (PC: Mitsubishi Engineering Plastics Co., Ltd., trade name “Iupilon Sheet”, type “NF-2000”) using a bar coater, It was heated and dried and cured at 130 ° C. for 60 minutes with a hot air circulating dryer to obtain a polycarbonate resin molded body whose surface was coated with a cured film derived from a filler-dispersed acrylic resin composition (cured film thickness: 10 μm). The haze value of the cured film before the Taber abrasion test was 1.5%, and it was confirmed that the silica filler was ultrafinely dispersed. Table 1 shows the results of evaluation of the polycarbonate resin molded body whose surface was coated with the cured film derived from the obtained filler-dispersed acrylic resin composition.

Example 2
Except for changing to the composition shown in Table 1 (7.9% silica filler mixed), the same treatment as in Example 1 was carried out, and a polycarbonate resin whose surface was coated with a cured film derived from a filler-dispersed acrylic resin composition A molded body was obtained. The cured film had a haze value of 1.2% before the Taber abrasion test, and it was confirmed that the silica filler was ultrafinely dispersed. The obtained polycarbonate resin molded body coated with the surface was evaluated and the results are shown in Table 1.

Example 3
Using a resin plate made of poly (methyl methacrylate) as a base material (PMMA: manufactured by Asahi Kasei Co., Ltd., trade name “Delagrass”, type “K”), heat drying and curing at 100 ° C. for 120 minutes with a hot air circulating dryer. A methacrylic resin molded body whose surface was coated with a cured film derived from a filler-dispersed acrylic resin composition was obtained in the same manner as in Example 2 except that.

Comparative Example 1
A cured film derived from a filler-dispersed acrylic resin composition, using a planetary ball mill (P-7, manufactured by FRITSCH), except that the revolution speed was changed to 500 rpm, with the same formulation as in Example 2. A polycarbonate resin molded body having a surface coated with was obtained. The cured film had a haze value of 7.3% before the Taber abrasion test, and the silica filler was not finely dispersed. Table 2 shows the results of evaluating the obtained polycarbonate resin molded body coated with the surface.

Comparative Example 2
Mixing (dispersing) time of a methoxy group-containing silane-modified acrylic resin and a methoxysilane partial condensate (manufactured by Tama Chemical Co., Ltd., trade name: methyl silicate 51) using a planetary ball mill (P-7 manufactured by FRITSCH) The polycarbonate resin molding which the surface was coat | covered with the cured film derived from a filler dispersion | distribution acrylic resin composition was performed in the same prescription as Example 2 except having made 30 minutes. Table 2 shows the results of evaluating the obtained polycarbonate resin molded body coated with the surface.

Comparative Example 3
Mixing (dispersing) temperature of a methoxy group-containing silane-modified acrylic resin and a methoxysilane partial condensate (manufactured by Tama Chemical Co., Ltd., trade name: methyl silicate 51) using a planetary ball mill (P-7 manufactured by FRITSCH) The polycarbonate resin molded body, the surface of which was coated with a cured film derived from a filler-dispersed acrylic resin composition, was obtained except that the temperature was 25 ° C. Table 2 shows the results of evaluating the obtained polycarbonate resin molded body coated with the surface.

Comparative Example 4
The surface is treated with a cured film derived from a filler-dispersed acrylic resin composition, except that the silica filler is added and dispersed so that the content of the silica filler is 13.0% by weight. A polycarbonate resin molded body coated with was obtained. Table 2 shows the results of evaluating the obtained polycarbonate resin molded body coated with the surface.

Comparative Example 5
Except that the silica filler was not added, the same formulation as in Example 2 was used to obtain a polycarbonate resin molded body whose surface was coated with a cured film derived from a filler-dispersed acrylic resin composition. Table 2 shows the results of evaluating the obtained polycarbonate resin molded body coated with the surface.

Comparative Example 6
A composition obtained by mixing a methoxy group-containing silane-modified acrylic resin and a silica filler so as to have the composition of wt% shown in Table 3 is a pre-dispersion composition, and the methoxy group-containing silane-modified acrylic resin and the methoxylane partial condensate. A polycarbonate resin molded body having a surface coated with a cured film derived from a filler-dispersed acrylic resin composition was obtained by performing the same treatment as in Example 2 except that the final composition was added. Table 3 shows the results of evaluating the obtained polycarbonate resin molded body coated on the surface.

Comparative Example 7
It is added so as to have the composition of the weight% shown in Table 3, and the surface is covered with a cured film derived from the filler-dispersed acrylic resin composition except that pre-dispersion is not performed and the treatment is performed in the same formulation A polycarbonate resin molded product was obtained. Table 3 shows the results of evaluating the obtained polycarbonate resin molded body coated on the surface.

  The filler-dispersed acrylic resin composition of the present invention and the production method thereof, and the transparent resin molded body whose surface is coated with the composition are effective in any application as long as the transparent resin molded body is used. It can be used for a resin molded body used in an environment with a lot of friction, and can be used particularly for plastic glass for automobiles.

It is a figure which illustrates typically the state of the filler dispersion acrylic resin composition in the present invention.

Explanation of symbols

  10 Silica filler, 12 methoxy group-containing silane-modified acrylic resin, 14 methoxysilane partial condensate, 20 filler-dispersed acrylic resin composition.

Claims (6)

Carboxyl group-containing acrylic polymer (1) and glycidyl ether group-containing methoxysilane partial condensate (2) obtained by demethanol reaction of glycidol and methoxysilane partial condensate are subjected to an epoxy ring-opening esterification reaction. A methoxy group-containing silane-modified acrylic resin,
A methoxysilane partial condensate;
A solvent,
A finely dispersed silica filler;
A filler-dispersed acrylic resin composition comprising: In the filler-dispersed acrylic resin composition according to claim 1,
The carboxy group-containing acrylic polymer (1) is an alkyl (meth) acrylate having an alkyl group having 1 to 2 carbon atoms, an alkyl (meth) acrylate having an alkyl group having 3 to 22 carbon atoms, and ethylenically unsaturated. A filler-dispersed acrylic resin composition, which is a copolymer of monomer components containing carboxylic acid. In the filler-dispersed acrylic resin composition according to claim 1 or 2,
A filler-dispersed acrylic resin composition, wherein a silica filler is dispersed in an ultrafine dispersion state using a disperser in which a strong shearing force works. Under the condition that the haze value measured at a coating cured film thickness of 10 μm is 1.5% or less,
(A) Epoxy ring-opening esterification reaction of carboxy group-containing acrylic polymer (1) and glycidyl ether group-containing methoxysilane partial condensate (2) obtained by demethanol reaction of glycidol and methoxysilane partial condensate A filler-dispersed acrylic system in which a silica filler is ultrafinely dispersed in a mixed liquid comprising a methoxy group-containing silane-modified acrylic resin, a (B) methoxysilane partial condensate, and a (C) solvent. A method for producing a resin composition.   A transparent resin molded article, the surface of which is coated with a cured film of the filler-dispersed acrylic resin composition according to any one of claims 1 to 3. In the transparent resin molded product according to claim 5,
The transparent resin molding is a plastic glass for automobiles.