JP5263607B2 - Inorganic oxide particle dispersion, curing agent and curing agent for epoxy resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inorganic oxide particle dispersion in which flocculation is not found even when a minute inorganic oxide with a mean particle diameter of &le;100 nm is used, and an epoxy resin cured article or the like excellent in transparency is easily prepared, moreover, viscosity is not easily increased even when content of the inorganic oxide particles is increased. <P>SOLUTION: The inorganic oxide particle dispersion is used in which an inorganic oxide particle (B) with a mean particle diameter of 5-100 nm obtained by reacting a carboxylic anhydride (b3) with a modified inorganic oxide particle (b) obtained by reacting a silane coupling agent and/or silylating agent (b2) having a functional group reactive with an inorganic oxide particle (b1) and a carboxylic anhydride (b3), is dispersed in a carboxylic anhydride (A). <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to an inorganic oxide particle dispersion, a curing agent, and a curing agent for epoxy resin.

Conventionally, a method has been known in which an inorganic oxide such as silica is dispersed in an epoxy resin composition to lower the coefficient of linear expansion, reduce internal stress, and improve the thermal shock resistance, strength, and elastic modulus of the cured product. ing. In the case of using an inorganic oxide, generally, the inorganic oxide is generally dispersed in an epoxy resin, mixed with a curing agent such as a carboxylic acid anhydride, and then thermally cured. However, the storage stability of the epoxy resin in which the inorganic oxide is dispersed is poor, and the increase in viscosity (thickening) of the resin over time is a problem (see Non-Patent Documents 1, 2, and 3).

As a method for reducing the linear expansion coefficient of the cured epoxy resin, it has been proposed to add silica powder having a particle size of 3 to 60 μm (see Patent Document 1). Thus, when the particle diameter of the inorganic oxide is large (about 0.1 to 100 μm), it is necessary to add a large amount of inorganic oxide particles in order to reduce the linear expansion coefficient. When an inorganic oxide is added, the viscosity of the epoxy compound is rapidly increased, and the amount added cannot be increased to a desired amount, so that there is a problem that internal stress cannot be reduced. In addition, a method has been proposed in which glass powder having a particle diameter of 5 to 40 nm is added to maintain the high transmittance while reducing the linear expansion coefficient and reducing internal stress (see Patent Document 2). However, although the increase in the viscosity of the epoxy resin is suppressed by adding a large amount of glass powder in order to reduce the linear expansion coefficient, it is still not sufficient. In addition, the epoxy resin composition in which the inorganic oxide is dispersed has poor heat stability, and there is a problem in that when it is stored at a high temperature, the epoxy group is ring-opened due to the hydroxyl group present on the surface of the particle, resulting in a significant increase in viscosity. . In particular, transparency is required for optical applications, and a minute inorganic oxide must be used. It can be said that a decrease in the transmittance of a cured product accompanying an increase in particle diameter due to aggregation is a fatal problem.

JP-A-11-74424 JP 2005-298701 A

Laurence E. Nielsen, “Mechanical Properties of Polymers and Composites”, Chemistry, 1976 D. M.M. Bigg, Polym. Eng. Sci. , 23, 206 (1983) Epoxy Resin Technology Association, "Review Epoxy Resin Basics II", Epoxy Resin Technology Association, November 19, 2003, pages 88-99

  The present invention can easily prepare an epoxy resin cured product having excellent transparency without aggregation even when a fine inorganic oxide having an average particle size of 100 nm or less is used. The main object is to provide an inorganic oxide particle dispersion in which the viscosity does not easily increase even when the content of is increased.

As a result of diligent studies to solve the above-mentioned problems, the present inventor normally disperses inorganic oxide particles obtained by reacting a specific compound in an acid anhydride used as a curing agent. I found out that it can be solved.

That is, the present invention is a silane coupling agent having an epoxy group to silica particles (b1) and / or silylating agent reaction of (b2) is, the silica particles (b1) 1 g, silane having an epoxy group cup The inorganic oxide particle dispersion according to claim 1, wherein the ring agent and / or silylating agent (b2) is 0.2 to 3 mmol; the curing agent containing the inorganic oxide particle dispersion; the inorganic oxide particles The present invention relates to a curing agent for epoxy resin containing a dispersion.

  According to the present invention, inorganic oxide particle dispersion that can easily prepare an epoxy resin cured product having excellent transparency without agglomeration even when a fine inorganic oxide having an average particle size of 100 nm or less is used. You can get a body. The inorganic oxide particle dispersion is obtained by uniformly dispersing an inorganic oxide in an acid anhydride. For example, an acid anhydride composition is made of raw materials (curing agent, epoxy resin, polyester resin, polyurethane resin, etc.). It can be used as a crosslinking agent. In particular, when used as a curing agent for epoxy resins, the strength and toughness can be improved while maintaining the transparency of the cured product of conventional epoxy resins and acid anhydrides.

The inorganic oxide particle dispersion of the present invention includes a silica particle (b1) (hereinafter referred to as component (b1)) and a silane having an epoxy group in carboxylic acid anhydride (A) (hereinafter referred to as component (A)). A modified inorganic oxide particle (b) (hereinafter referred to as component (b)) obtained by reacting a coupling agent (b2) (hereinafter referred to as component (b2)) is allowed to react with a carboxylic acid anhydride (b3). Inorganic oxide particles (B) having an average particle diameter of 5 to 100 nm (hereinafter referred to as component (B)) are dispersed.

The component (A) used in the present invention is not particularly limited as long as it is an anhydride of carboxylic acid having at least two carboxyl groups in one molecule, and a known one can be used. Specifically, for example, aromatic carboxylic anhydrides such as phthalic anhydride, trimellitic anhydride and pyromellitic anhydride, aliphatic carboxylic anhydrides such as maleic anhydride and glutaric anhydride, hexahydrophthalic anhydride Examples thereof include alicyclic carboxylic acid anhydrides such as acid, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, and nadic anhydride. These may be used alone or in combination of two or more. Among these acid anhydrides, it is preferable to use hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phthalic anhydride, and tetrahydrophthalic anhydride. In particular, it is preferable to use hexahydrophthalic anhydride or methylhexahydrophthalic anhydride because it is suitable for improving yellowing resistance as a cured epoxy resin and suitable for optical applications. In addition, when a component (A) is not liquid, it is preferable to use the organic solvent used when disperse | distributing the component (B) mentioned later as needed.

  The component (B) used in the present invention is obtained by reacting the component (b3) with the component (b) obtained by reacting the component (b1) with the component (b2).

The average particle diameter of the component (b1) used in the present invention is usually preferably set to about 5 nm to 100 nm, particularly preferably to 5 to 80 nm. Particles having an average particle size of less than 5 nm are difficult to prepare, and even if obtained, the particle size is too small, so the strength of the coating containing inorganic oxide particles is weak, and the coating has good adhesion to the substrate. Since it gets worse, it is not preferable. Further, if the average particle diameter exceeds 100 nm, the strength of the coating containing inorganic oxide particles is lowered, the adhesion of the coating to the base material is deteriorated, and further, a stable dispersion state cannot be maintained and sedimentation may occur. Therefore, it is not preferable.

In addition, you may use a commercially available dispersion as it is for a component (b1). As a commercial item (trade name), for example, as silica particle dispersion, methanol silica sol, IPA-ST, MEK-ST, MIBK-ST, XBA-ST, DMAC-ST, ST-20, ST-40, ST -C, ST-N, ST-O, ST-50, ST-OL (above, manufactured by Nissan Chemical Industries, Ltd.), Organosol PL-2L-MA, PL-2L-IPA, PL-2PGME (above, Fuso Chemical Industry Co., Ltd.) as silica particles, Aerosil 130, Aerosil 300, Aerosil 380, Aerosil TT600, Aerosil OX50 (above, Nippon Aerosil Co., Ltd.), Sildex H31, Sildex H32, Sildex H51 Sildex H52, Sildex H121, Sildex H122 (above, manufactured by Asahi Glass Co., Ltd.), E22 A, E220 (manufactured by Nippon Silica Industrial Co., Ltd.), (manufactured by Fuji Silysia Chemical (Co., Ltd.)) SYLYSIA470, the SG Flake (manufactured by Nippon Sheet Glass Co., Ltd.), and the like, can be cited. Furthermore, a silica particle dispersion liquid dispersed in an organic solvent compatible with water and silica particles dispersed in water may be mixed. Examples of silica particles dispersed in water include Snowtex series (manufactured by Nissan Chemical Industries, Ltd.), silica doll series (manufactured by Nippon Chemical Industry Co., Ltd.), and cataloid series (manufactured by Catalytic Chemical Industries, Ltd.). be able to. Among these, a silica particle dispersion in which the dispersion is acidic is particularly preferable. Moreover, what added the organic solvent compatible with water to the silica particle disperse | distributed in water can also be used.

As a component (b2), if it is a silane coupling agent and / or silylating agent which have an epoxy group in 1 molecule, it will not be limited but a well-known thing can be used. In the present invention, the silane coupling agent is a compound having a hydrolysis group such as an epoxy group and an alkoxy group. The silylating agent is a silane compound that does not have a hydrolyzing group such as an alkoxy group having an epoxy group . Specific examples of the silane coupling agent include, for example, general formula (1): Z _4-n SiX _n (wherein the epoxy group , X represents an alkoxy group, a halogen group, or an amino group. It is an integer of 3.) The compound represented by this can be used. Specifically, as the silylating agent, the general formula (2):

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are organic functional groups, at least one of which is an epoxy group ) can be used. The organic functional group is not particularly limited as long as it is other than a hydrolyzable group such as an alkoxy group, and examples thereof include known ones. Specifically as an organic functional group, a C1-C20 alkyl group, a phenyl group, etc. are mentioned, for example . As the epoxy group, 3,4-epoxycyclohexyl group, and a 3-glycidoxypropyl group.

Specific examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycid. propyl methyl diethoxy silane, such as a silane coupling agent having an epoxy group such as 3-glycidoxypropyl triethoxy silane. Examples of the silylating agent include 3-glycidoxypropylpentamethyldisiloxane. These may be used alone or in combination of two or more. Among these, a silane coupling agent having an epoxy group is preferable. In particular, the use of a silane coupling agent having an epoxy group and a dialkoxysilyl group facilitates the reaction with the carboxylic acid anhydride group of the component (b3). The dispersibility of the obtained component (B) in the component (A) can be increased, the viscosity can be lowered, and when the curing reaction with the epoxy compound is carried out, it can be fixed by bonding in the matrix. It is preferable from the point. When the viscosity of the dispersion increases after dispersion of component (B) in component (A), hexamethyldisiloxane, 1,3-dibutyltetramethyldisiloxane, 1,3-diphenyltetramethyldi Siloxane, 1,3-divinyltetramethyldisiloxane, hexaethyldisiloxane, hexamethyldisilazane, trimethylmethoxysilane, trimethylethoxysilane, trimethylpropoxysilane, phenyldimethylmethoxysilane, chloropropyldimethylmethoxysilane, 3-glycidoxy Viscosity can be lowered by reacting a silane compound such as propylpentamethyldisiloxane again with the component (b) obtained by reacting the component (b1) with the component (b2). In addition, these silane compounds may be used individually by 1 type, or 2 or more types may be mixed and used for them. The amount of the silane compound added is preferably about 10 to 100 mol% with respect to the amount of the component (b2).

As the component (b3) used for the production of the component (B), in addition to the same component (A) described above, a dehydration condensate of a monocarboxylic acid such as acetic anhydride, propionic anhydride, benzoic anhydride or the like is used. be able to. In order to stably disperse the component (B) in the component (A), the component (b3) is preferably the same as the component (A).

  Although the reaction amount of the component (b2) with respect to the component (b1) is not particularly limited, it is generally sufficient to react about 0.2 to 3 mmol of the component (b2) with respect to 1 g of the component (b1), preferably 0. .4 to 2.5 mmol. It is difficult to react the coupling agent in excess of 3 mmol, and in the case of less than 0.2 mmol, when the alcohol solvent is replaced with an organic solvent such as other ketones, the particles become unstable, and aggregates / lumps are formed. It may precipitate.

  Moreover, the reaction amount of the component (b3) with respect to the component (b) is not particularly limited, but usually the component (b3) is about 0.2 to 3 mmol, preferably 0. 4-2.5 mmol.

  The reaction method of component (b1) and component (b2) is not particularly limited, and a known method may be employed. Specifically, for example, a method in which the component (b2) is heated and reacted at about 30 ° C. to 150 ° C. using an acid catalyst, water, and, if necessary, an organic solvent in the presence of the component (b1) is employed. can do. In addition, if the component (b1) itself is acidic, it is not always necessary to add an acid catalyst. Examples of the organic solvent include methyl alcohol, ethyl alcohol, 2-propyl alcohol, n-butyl alcohol, n-octyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, propyl glycol monomethyl ether. Alcohols such as propyl glycol monoethyl ether are preferred. The reaction is carried out under acidic conditions of pH less than 7, preferably pH 2 to pH 6, and an acid catalyst may be added as necessary. The reaction temperature is about 30 ° C. to 150 ° C. for about 1 hour to 15 hours, Preferably, the reaction is performed for 2 to 12 hours, and when the obtained reaction solution is acidic, it is preferable to neutralize with an ion exchange resin, an alkali, an acid adsorbent, or the like.

  The reaction method between the component (b) and the component (b3) is not particularly limited, and a known method may be employed. Specifically, for example, a method in which each component is heated and reacted at about 10 ° C. to 150 ° C. in the presence of an organic solvent as necessary can be employed. If the reaction does not proceed easily, an acid catalyst may be added. In addition, the solvent to be used will not be specifically limited if it is inactive with respect to a component (b3), A well-known thing can be used. The component (B) thus obtained has an average particle size of about 5 to 100 nm.

  In addition, a component (B) can also be used for preparation of an inorganic oxide particle dispersion as a dispersion liquid disperse | distributed to the suitable solvent as needed. The solvent is not particularly limited as long as it is inert to acid anhydrides and has an appropriate volatility. For example, ethers such as diethyl ether and tetrahydrofuran; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone Ketones such as ethyl acetate, n-butyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, γ-butyrolactone and other esters or lactones; aromatic carbonization such as benzene, toluene, xylenes, etc. Hydrogens; Amides or lactams such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like can be mentioned. These solvents can be used alone or in admixture of two or more. The solid content concentration of the dispersion of inorganic oxide particles is usually about 1 to 60% by weight, preferably 5 to 50% by weight.

  The inorganic oxide particle dispersion of the present invention is obtained by dispersing about 3 to 70 parts by weight (solid content), preferably 5 to 50 parts by weight of component (B) with respect to 100 parts by weight of component (A). It is. In addition, when the usage-amount of a component (B) exceeds 70 weight part, there exists a possibility that a composition may thicken and handling may become difficult.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The pH measurement, average particle diameter measurement, and surface coating amount were determined by the following methods. In the examples, “%” is based on weight.

pH measurement method Neutralized surface-coated silica sol dispersion was diluted with ion-exchanged water so that the solution concentration was 1% with respect to silica sol, and a pH meter (device name: “D-52”, manufactured by Horiba, Ltd.) ) And measured at 25 ° C.

Measuring method of average particle diameter The average particle diameter is measured at 25 ° C. using a dynamic light scattering apparatus (device name: “FPAR-3”, using a concentrated probe, manufactured by Otsuka Electronics Co., Ltd.). The value determined by cumulant analysis was adopted.

Method for measuring surface reaction amount The silica sol dispersed in the obtained organic solvent was mixed with n-hexane, and the agglomerated silica sol was treated with a centrifuge (3000 rpm, 30 minutes) to separate the dispersion solvent and the silica sol. After removing the supernatant, tetrahydrofuran was added to the residue to redisperse the silica sol particles, and n-hexane was further added to aggregate the silica sol. This operation was repeated, and it was confirmed by gas chromatography that there was no silane coupling agent that did not react with the silica sol surface in the supernatant. The silica sol was dried at 105 ° C. for 3 hours, and thermal analysis of the obtained solid (device name: “TG-DTA 2000S”, manufactured by Bruker AXS Co., Ltd., heating rate: 10 ° C./min, The amount of coupling agent reacted per unit weight of silica sol was calculated from the weight loss at that time.

Viscosity Measuring Method Viscosity is a value measured using an E-type viscometer device (product name: “RE-80E”, cone: 1 ° 30 ′ × 24, manufactured by Tokyo Keiki Co., Ltd.). The measurement temperature is 25 ° C.

Example 1
To a four-necked round bottom flask equipped with a stirrer, stirring blade, condenser, dropping funnel, thermometer and nitrogen line, silica / 2-propyl alcohol dispersion (manufactured by Nissan Chemical Industries, Ltd., trade name “IPA-ST”) ) 300 g (silica solid content 32%, average particle diameter 20 nm), ion-exchanged water 15.7 g, and 2-propyl alcohol 4.3 g were charged and heated to 80 ° C. while stirring under a nitrogen stream. Subsequently, 96 g of 3-glycidoxypropylmethyldimethoxysilane (manufactured by Toray Dow Corning Co., Ltd., trade name “Z-6044”) dissolved in 224 g of 2-propyl alcohol was added dropwise over 1 hour, and the addition was completed. Thereafter, the surface of the silica sol was coated by maintaining the temperature for 6 hours under reflux. By neutralizing this surface-coated silica sol dispersion with a 0.1 mol / l potassium hydroxide / ethyl alcohol solution (manufactured by Wako Pure Chemical Industries, Ltd.), the average particle size of the surface-coated silica sol is 21 nm and the reaction amount is 1. A neutralized surface-coated silica sol dispersion having a pH of 6.5 at 0.0 mmol / g (reaction amount of (b2) with respect to (b1)) was obtained.
Next, 600 g of the neutralized surface-coated silica sol dispersion obtained above is charged into a round bottom flask equipped with a stirrer, stirring blade, moisture meter, condenser, and thermometer so that the concentration becomes 10%. 1,200 g of ethyl methyl ketone was added. While stirring, the mixture was heated to 80 ° C., and ethyl methyl ketone, ethyl alcohol, and 2-propyl alcohol were azeotropically distilled to increase the concentration to 20%. Between these concentrations, ethyl methyl ketone was added and ethyl methyl ketone, ethyl alcohol, and 2-propyl alcohol were distilled off, and finally the dispersion medium was replaced with ethyl methyl ketone at a sol concentration of 20%.
80 g of a mixture of 4-methylhexahydrophthalic anhydride and hexahydrophthalic anhydride (manufactured by Shin Nippon Rika Co., Ltd., trade name “Licacid MH-700”) was added to 400 g of the obtained surface-coated silica sol ethyl methyl ketone dispersion. The mixture was refluxed at 80 ° C. for 1 hour with stirring. After completion of the reaction, 158 g of acid anhydride in which silica reacted with the silane coupling agent and acid anhydride was dispersed on the surface of the silica particles by distilling off ethyl methyl ketone with a rotary evaporator under reduced pressure (15 hPa). (Yield 99%). At this time, the reaction amount was 0.8 mmol / g (reaction amount of (b3) with respect to (b)).

Example 2
A four-necked round bottom flask equipped with a stirrer, stirring blade, condenser, dropping funnel, thermometer and nitrogen line was charged with 300 g of “IPA-ST”, 21.9 g of ion-exchanged water, and 318 g of 2-propyl alcohol. The mixture was heated to 80 ° C. with stirring under an air stream. Next, 96 g of 3-glycidoxypropyltrimethoxysilane (manufactured by Toray Dow Corning Co., Ltd., trade name “Z-6040”) dissolved in 544 g of 2-propyl alcohol was added dropwise over 1 hour, and the addition was completed. Thereafter, the mixture was kept under reflux for 6 hours. Subsequently, 64 g of hexamethyldisiloxane (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added, and the mixture was further heated for 4 hours under reflux, whereby a silica sol surface coating treatment was performed. By neutralizing this surface-coated silica sol dispersion with a 0.1 mol / l potassium hydroxide / ethyl alcohol solution, the average particle size of the surface-coated silica sol is 20 nm and the reaction amount is 1.4 mmol / g ((b1) In the reaction amount b2), a neutralized surface-coated silica sol dispersion having a pH of 6.5 was obtained.
Next, according to Example 1, the dispersion medium of the neutralized surface-coated silica sol dispersion was replaced with ethyl methyl ketone. 80 g of “Licacid MH-700” was added to 400 g of the obtained surface-coated silica sol ethyl methyl ketone dispersion, and the mixture was refluxed at 80 ° C. for 1 hour with stirring. After completion of the reaction, the ethyl methyl ketone is distilled off with a rotary evaporator under reduced pressure (15 hPa), whereby the silica particles are reacted with a silane coupling agent, a silylating agent, and an acid anhydride. 158 g (99% yield) of anhydride was obtained. At this time, the reaction amount was 1.0 mmol / g (reaction amount of (b3) with respect to (b)).

Comparative Example 1
A four-necked round bottom flask equipped with a stirrer, stirring blade, condenser, dropping funnel, thermometer and nitrogen line was charged with 500 g of “IPA-ST”, 2.0 g of ion-exchanged water, and 564 g of 2-propyl alcohol. The mixture was heated to 80 ° C. with stirring under an air stream. Next, a solution obtained by dissolving 18.2 g of hexamethyldisiloxane in 103.0 g of 2-propyl alcohol was dropped over 1 hour, and after completion of the dropwise addition, the silica sol was subjected to a surface coating treatment by incubating for 6 hours under reflux. It was. By neutralizing this surface-coated silica sol dispersion with a 0.1 mol / l potassium hydroxide / ethanol solution, the average particle size of the surface-coated silica sol was 18 nm, and the reaction amount was 0.3 mmol / g ((b2) relative to (b1) ), A neutralized surface-coated silica sol dispersion having a pH of 6.5 was obtained.
Next, according to Example 1, the dispersion medium of the neutralized surface-coated silica sol dispersion was replaced with ethyl methyl ketone. To 400 g of the obtained surface-coated silica sol ethyl methyl ketone dispersion, 186.7 g of “Ricacid MH-700” was added, stirred at 25 ° C. for 1 hour, and then the ethyl methyl ketone was distilled with a rotary evaporator under reduced pressure (15 hPa). By leaving, 264 g (yield 99%) of an acid anhydride in which silica whose surface was reacted with a silane agent was dispersed was obtained.

Comparative Example 2
A four-necked round bottom flask equipped with a stirrer, stirring blade, condenser, dropping funnel, thermometer and nitrogen line was charged with 300 g of “IPA-ST”, 7.8 g of ion-exchanged water, and 12.2 g of 2-propyl alcohol. The mixture was heated to 80 ° C. with stirring under a nitrogen stream. Subsequently, 48 g of n-propyltrimethoxysilane (trade name “Z-6265”, manufactured by Toray Dow Corning Co., Ltd.) dissolved in 112 g of 2-propyl alcohol was added dropwise over 1 hour. A surface coating treatment was performed by keeping the temperature for 6 hours below. By neutralizing 480 g of this surface-coated silica sol dispersion with a 0.1 mol / l potassium hydroxide / ethyl alcohol solution, the average particle diameter of the surface-coated silica sol is 23 nm and the reaction amount is 0.8 mmol / g ((b1)). In (reaction amount of (b2)), a neutralized surface-coated silica sol dispersion having a pH of 6.5 was obtained.
Next, according to Example 1, the dispersion medium of the neutralized surface-coated silica sol dispersion was replaced with ethyl methyl ketone. 187 g of “Licacid MH-700” was added to 400 g of the obtained surface-coated silica sol ethyl methyl ketone dispersion, and the mixture was refluxed at 80 ° C. for 1 hour with stirring. After completion of the reaction, ethyl methyl ketone was distilled off with a rotary evaporator under reduced pressure (15 hPa), whereby 284 g (99% yield) of an acid anhydride in which silica obtained by reacting the surface of the silica particles with a silane coupling agent was dispersed. )Obtained.

Comparative Example 3
In a four-necked round bottom flask equipped with a stirrer, stirring blade, condenser, dropping funnel, thermometer and nitrogen line, 50 g of silica powder (manufactured by Fuji Silysia Chemical Ltd., average particle size 3 μm), 4.1 g of ion-exchanged water. , And 195.9 g of 2-propyl alcohol, and the temperature was raised to 80 ° C. while stirring under a nitrogen stream. Next, 25 g of “Z-6044” dissolved in 100 g of 2-propyl alcohol was added dropwise over 1 hour, and after completion of the addition, the mixture was kept warm for 6 hours under reflux to perform surface coating treatment. By neutralizing this surface-coated silica sol dispersion with a 0.1 mol / l potassium hydroxide / ethyl alcohol solution (average particle diameter of the surface-coated silica sol is 385 nm, the reaction amount is 0.7 mmol / g ((b1)) In (reaction amount of (b2)), a neutralized surface-coated silica sol dispersion having a pH of 6.5 was obtained.
Next, according to Example 1, the dispersion medium of the neutralized surface-coated silica sol dispersion was replaced with ethyl methyl ketone. 140 g of “Licacid MH-700” was added to 300 g of the obtained surface-coated silica sol ethyl methyl ketone dispersion, and the mixture was refluxed at 80 ° C. for 1 hour with stirring. After completion of the reaction, 198 g of acid anhydride in which silica reacted with the silane coupling agent and acid anhydride was dispersed on the surface of the silica particles by distilling off ethyl methyl ketone with a rotary evaporator under reduced pressure (15 hPa). (Yield 99%). At this time, the reaction amount was 0.6 mmol / g (reaction amount of (b3) with respect to (b)).

Table 1 shows the measured values of the inorganic oxide particle dispersions of Examples 1-2 and Comparative Examples 1-4 synthesized as described above.

表中、シランカップリング剤の項において、Ａは３−グリシドキシプロピルメチルジメトキシシラン、Ｂは、３−グリシドキシプロピルトリメトキシシラン、Ｄは、ｎ−プロピルトリメトキシシランを表す。また、シリル化剤の項におけるＣはヘキサメチルジシロキサンを表す。

In the table, in the term of silane coupling agent, A represents 3-glycidoxypropylmethyldimethoxysilane, B represents 3-glycidoxypropyltrimethoxysilane, and D represents n-propyltrimethoxysilane. C in the term of silylating agent represents hexamethyldisiloxane.

As shown in Table 1, although the SiO ₂ concentration in the inorganic oxide particle dispersions in the examples is higher than that in the comparative examples, the viscosity is low and stable. The viscosity of the dispersion in the comparative example exceeds 21,000 mPa · s, and it becomes difficult to handle in the mixing operation with the resin during production or molding.

Claims (6)

In the carboxylic acid anhydride (A), the silica particles (b1) and the modified inorganic oxide particles (b) obtained by reacting the silane coupling agent and / or silylating agent (b2) having an epoxy group are reacted with carboxylic acid anhydride (A). An inorganic oxide particle dispersion in which inorganic oxide particles (B) having an average particle diameter of 5 to 100 nm obtained by reacting the acid anhydride (b3) are dispersed. Silane coupling agent having an epoxy group and / or a silylating agent to silica particles (b1) the reaction of (b2) is, the silica particles (b1) 1 g, silane coupling agent having an epoxy group and / or silyl The inorganic oxide particle dispersion according to claim 1, wherein the agent (b2) is 0.2 to 3 mmol. The reaction amount of the carboxylic acid anhydride (b3) with respect to the modified inorganic oxide particles (b) is 0.2 to 3 mmol of the carboxylic acid anhydride (b3) with respect to 1 g of the modified inorganic oxide particles (b). Item 3. The inorganic oxide particle dispersion according to Item 1 or 2. The inorganic oxide according to any one of claims 1 to 3, comprising 3 to 70 parts by weight of inorganic oxide particles (B) having an average particle diameter of 5 to 100 nm with respect to 100 parts by weight of the carboxylic acid anhydride (A). Particle dispersion. The hardening | curing agent containing the inorganic oxide particle dispersion in any one of Claims 1-4 . The hardening | curing agent for epoxy resins containing the inorganic oxide particle dispersion in any one of Claims 1-4 .