JP5297598B2 - Curable epoxy resin composition and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable epoxy resin composition that is imparted with a high refractive index while retaining transparency of an epoxy resin by introducing a metal alkoxide into the epoxy resin and uniformly compounding them, and a cured product thereof. <P>SOLUTION: The curable epoxy resin composition comprises as essential ingredients (A) an alkoxysilyl group-modified epoxy resin obtained by causing a silane compound (a-2) bearing both at least one mercapto group and at least one alkoxy group bonded to a silicon atom in one molecule to react with an epoxy group in an epoxy resin (a-1), (B) at least one metal alkoxide selected from the group consisting of titanium alkoxide, zirconium alkoxide and aluminum alkoxide and/or a hydrolyzate-partial condensate thereof, and (C) water. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a curable epoxy resin composition comprising an epoxy resin and a metal alkoxide, and a method for producing the same, and further, a cured product having excellent transparency and a high refractive index obtained by curing the curable epoxy resin composition. It is about.

  Epoxy resins are excellent in electrical properties, mechanical properties, and thermal properties, and are used in a wide variety of fields such as electrical / electronic materials, paints, adhesive materials, molding materials, and civil engineering materials. Epoxy resins are also excellent in transparency and have been widely used in optical applications such as sealing resins for optical semiconductors. However, various properties required for epoxy resins have become increasingly severe in recent years, and it has become difficult to satisfy the required physical properties with epoxy resins alone. Therefore, a so-called organic-inorganic hybrid material in which an inorganic material such as silica or silsesquioxane is combined with an epoxy resin has been proposed to improve physical properties such as heat resistance, strength, and dimensional stability (for example, patents). Reference 1).

  On the other hand, in optical applications such as sealing materials and lens materials, in recent years, there has been an increasing demand for improved light extraction efficiency and thinner (lighter) molded products. ing. As one method for increasing the refractive index of a resin material, a method in which metal oxide fine particles having a high refractive index such as titanium oxide are combined has been studied (see, for example, Patent Document 2). There are many known examples of composites of epoxy resins with metal oxides such as titanium oxide.

  Patent Documents 3 and 4 disclose an epoxy resin-metal oxide composite obtained by hydrolyzing and condensing a metal alkoxide in an epoxy resin. This material is excellent in transparency and can be suitably used as an LED sealing material. However, amine compounds and organometallic compounds used as catalysts for metal alkoxide hydrolysis and condensation reactions also promote epoxy group ring-opening reactions. These curing reactions proceed simultaneously, and it is difficult to obtain a uniform cured body with good workability. Moreover, in the Example of these patent documents, only the usage example of alkoxysilane is shown as a metal alkoxide. Compared with silicon, titanium and zirconium alkoxides have extremely high reactivity, and the resulting titanium oxide and zirconium oxide have a low surface potential, so that the generated fine particles grow rapidly and are likely to agglomerate. Therefore, it is much more difficult to uniformly disperse these metal oxides in the epoxy resin as fine particles than in the case of silicon.

Patent Document 5 also discloses an epoxy resin composition containing an epoxy resin, a curing agent, and an alkoxytitanium. In such a composition that does not give any ingenuity by simply adding an alkoxytitanium, a titanium alkoxide is disclosed. It is difficult to obtain a transparent material because the titanium oxide obtained from the above forms relatively large particles by aggregation. In particular, the tendency becomes more remarkable as the amount of titanium oxide added is increased.
Patent Document 6 discloses a curable resin composition in which a titanium alkoxide and an epoxy resin are combined with a titanate coupling agent. However, titanate coupling agents are generally colored yellow to brown and are not suitable for use in preparing a resin composition for optical materials.

Patent Documents 7 and 8 describe a composite method of an epoxy resin and a metal alkoxide when an amine-based curing agent is used. However, the amine-based curing agent tends to cause coloration of the cured product, and is not suitable as a curing agent when the cured product is used as an optical material.
About all the epoxy resin compositions disclosed in the above Patent Documents 3 to 8, physical properties such as strength, moisture resistance, heat resistance, and antibacterial properties are imparted by compounding with metal oxides, but the refractive index. There is no description about the optical characteristics.

  As another method for compounding titanium alkoxide with an epoxy resin, Non-Patent Documents 1 and 2 include mixing an epoxy resin with a silane coupling agent having a primary amino group and titanium butoxide in a solvent to obtain an amino group / epoxy. A method is disclosed in which a reaction between groups and a hydrolytic condensation reaction between silicon and titanium alkoxide are simultaneously performed. However, there is no description about optical characteristics such as refractive index. Further, when the primary amino group reacts with the epoxy resin, the epoxy resin undergoes a curing reaction and gels, so that a uniform and transparent cured product cannot be obtained.

Patent Documents 9 and 10 disclose a method of reacting a silane compound having a mercapto group with an epoxy resin, but there is no description about a combination with a metal alkoxide.
Patent Document 11 discloses a primer composition comprising a reaction product of an organosilicon compound having a mercapto group and an alkoxy group and an epoxy compound, and a titanate ester. This titanate is added as a hydrolysis catalyst of the organosilicon compound, and there is no description about the effect on optical properties such as refractive index.

JP-A-10-298405 JP 2003-073559 A Japanese Patent Laid-Open No. 06-239964 JP 2006-070266 A JP 2000-319362 A JP 2002-187935 A Japanese Patent Laid-Open No. 08-100107 JP 2005-036080 A Japanese Patent Application Laid-Open No. 07-033786 JP-A-11-209579 Japanese Patent Laid-Open No. 03-242268 Shoichiro Yano et al., Polymer Papers, 2003, Volume 60, Number 9, 490 S. Yano et al., Polymer International, 2005, 54, 354.

  The present invention was made in view of the above circumstances, and by introducing a metal alkoxide into an epoxy resin and uniformly compounding it, while maintaining the transparency of the epoxy resin, imparting a high refractive index, Another object is to arbitrarily control the refractive index by widely changing the amount of metal alkoxide added.

As a result of intensive investigations to solve the above problems, the present inventors have reacted a specific silane compound with an epoxy resin, and then added a metal alkoxide to cause hydrolytic condensation. It has been found that even if the amount is increased, it can be compounded without impairing transparency and uniformity, and the present invention has been completed based on this finding.
That is, this invention provides the curable epoxy resin composition as described below, its hardened | cured material, and its manufacturing method.

(1) Reacting the epoxy group of the epoxy resin (a-1) with a silane compound (a-2) having simultaneously one mercapto group and at least one alkoxy group bonded to a silicon atom in one molecule. resulting Te alkoxysilyl group-modified epoxy resin (a), the titanium alkoxide, and zirconium alkoxy least one metal alkoxide and / or a hydrolysis partial condensation product selected from de by Li Cheng group (B), water (C) Is an essential component, and the amount of the component (B) used relative to the component (A) is such that the metal content derived from the metal alkoxide is 5 to 50% by mass in terms of the metal oxide in the cured product. The amount of the curable epoxy resin composition.
(2) A cured product obtained by curing the curable epoxy resin composition of (1) by a process including a hydrolysis condensation reaction.
(3) refractive index at a wavelength of 589.3nm is characterized in that 1.59 or more (2) Symbol mounting cured product.
( 4 ) An optical member comprising the cured product according to (2) or (3) .
( 5 ) React the epoxy group of the epoxy resin (a-1) with a silane compound (a-2) having one mercapto group and one alkoxy group bonded to at least one silicon atom in one molecule. A process for producing an alkoxysilyl group-modified epoxy resin (A), and (A) comprising at least one metal alkoxide selected from the group consisting of a titanium alkoxide, a zirconium alkoxide and an aluminum alkoxide and / or a hydrolysis partial condensation thereof. object (B) and in the presence of water (C) viewed including the step of hydrolysis and condensation reaction, the amount of the component (B) with respect to the (a) component, the content of the metal derived from the metal alkoxide is cured The manufacturing method of the hardened | cured material which is the quantity used as 5-50 mass% in conversion of the metal oxide in a thing .

  ADVANTAGE OF THE INVENTION According to this invention, the curable epoxy resin composition which is excellent in transparency and has a high refractive index, and its hardening body are provided. This material can be suitably used as an optical member such as a sealing material, various lens materials, a coating material such as an antireflection film, an optical waveguide, an optical adhesive, a display substrate, and an optical disk substrate.

Hereinafter, the present invention will be specifically described.
<(A) component>
The alkoxysilyl group-modified epoxy resin as the component (A) constituting the curable epoxy resin composition of the present invention is obtained by reacting the component (a-1) and the component (a-2) described below.
[(A-1) component: epoxy resin]
The epoxy resin used as the component (a-1) of the present invention has two or more epoxy groups in one molecule, and known epoxy resins can be used. For example, bisphenol A, bisphenol F, bisphenol S, tetrabromobisphenol A, biphenol, tetramethylbiphenol, tetraphenylolethane, hydroquinone, methylhydroquinone, dimethylhydroquinone, trimethylhydroquinone, resorcinol, methylresorcinol, catechol, methylcatechol, dihydroxynaphthalene , Dihydroxymethylnaphthalene, dihydroxydimethylnaphthalene, phenol novolak, cresol novolak, and other phenolic glycidyl ether type epoxy resins; hydrogenated epoxy resins obtained by hydrogenating aromatic rings of these phenol type glycidyl ether type epoxy resins; polypropylene glycol Alcohol-based glycidyl ether type epoxy resin Glycidyl ester type epoxy resin made from hexahydrophthalic anhydride, dimer acid, etc .; Glycidylamine type epoxy resin such as hydantoin, isocyanuric acid, diaminodiphenylmethane; 3 ′, 4′-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxy Cycloaliphatic epoxies such as 1,2: 8,9-diepoxy limonene, 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol Resin; 1,3-bis [2- (3,4-epoxycyclohexyl) ethyl] -1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetrakis [2- (3,4) -Epoxycyclohexyl) ethyl] -1,3,5,7-tetramethylcyclotetrasiloxy An epoxy silicone compound such as sun can be used, and these may be used alone or in combination of two or more. Among these, bisphenol A glycidyl ether type epoxy resin, hydrogenated bisphenol A glycidyl ether type epoxy resin, and 3 ′, 4′-epoxycyclohexylmethyl-3,4-epoxycyclohexyl carboxylate are particularly preferably used.

[(A-2) Component: Silane Compound]
The silane compound simultaneously having one mercapto group and at least one alkoxy group bonded to a silicon atom in one molecule used as the component (a-2) of the present invention is usually commercially available as a mercapto silane coupling agent. These can be used alone or in combination of two or more. Specific examples include mercaptomethyltrimethoxysilane, mercaptomethyltriethoxysilane, mercaptomethylmethyldimethoxysilane, mercaptomethylmethyldiethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercapto. Examples thereof include propylmethyldimethoxysilane and 3-mercaptopropylmethyldiethoxysilane. The mercapto group is more preferably used than the primary amino group and the like in that the reactivity with the epoxy group is high, coloring does not occur after the reaction and curing, and a high refractive index can be expected due to the effect of the sulfur atom.

  The component (A) of the present invention is an alkoxysilyl group-modified epoxy resin obtained by reacting the component (a-2) with the epoxy group of the epoxy resin as the component (a-1). In this reaction, the mercapto group of component (a-2) undergoes an addition reaction with the epoxy group of the epoxy resin to produce an epoxy resin having an alkoxysilyl group.

  Regarding the reaction ratio of the component (a-2) to the component (a-1), it is a standard to react an equivalent or small excess of mercapto group with the epoxy group in the component (a-1). The group can also be in excess. The specific reaction ratio is, for example, a range in which the mercapto group is 0.2 to 1.5 mol, more preferably 0.5 to 1.2, with respect to 1 mol of the epoxy group in the component (a-1). It is selected from the range of mol, more preferably 0.8 to 1.1 mol. The reaction is carried out at a reaction temperature of 0 to 150 ° C., preferably 20 to 100 ° C., for 0.5 to 10 hours, preferably 2 to 5 hours.

  The reaction can be performed without a solvent, and alcohol solvents such as methanol, ethanol, isopropanol, and butanol; tetrahydrofuran, 1,4-dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene Ether solvents such as glycol diethyl ether; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; aprotic polar solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; halogen solvents such as dichloromethane and chloroform, toluene In addition, one or two or more selected from aromatic solvents such as xylene can be used.

It is preferable to use a catalyst for this reaction. Specific examples of the catalyst include 1,8-diaza-bicyclo [5.4.0] -7-undecene, triethylenediamine, 2,4,6-tris (dimethylaminomethyl) phenol, and 2- (dimethylaminomethyl). Tertiary amines such as phenol, dimethylbenzylamine, dimethylcyclohexylamine, triethanolamine, dimethylaminoethanol, N-methylmorpholine, tetramethylpropylenediamine, tetramethylhexamethylenediamine, pentamethyldiethylenetriamine and their salts; Examples include organic phosphine compounds such as methyldiphenylphosphine, triphenylphosphine, and tris (dimethoxyphenyl) phosphine.
The addition reaction of the component (a-1) and the component (a-2) described above is an analytical method such as nuclear magnetic resonance analysis ( ¹ H-NMR method) or Fourier transform infrared spectroscopy (FT-IR method). Can be tracked by.

<(B) component>
Component (B) of the present invention is a component for imparting a high refractive index, and is at least one metal alkoxide selected from the group consisting of titanium alkoxide, zirconium alkoxide, and aluminum alkoxide and / or a hydrolyzed partial condensate thereof. It is. Specific examples of the metal alkoxide include titanium tetramethoxide, titanium tetraethoxide, titanium tetra n-propoxide, titanium tetraisopropoxide, titanium tetra n-butoxide, titanium t-butoxide, zirconium tetramethoxide, zirconium tetraethoxy. Zirconium tetra n-propoxide, zirconium tetraisopropoxide, zirconium n-tetrabutoxide, zirconium tetra t-butoxide, aluminum trimethoxide, aluminum triethoxide, aluminum tri n-propoxide, aluminum triisopropoxide, Examples include aluminum tri-n-butoxide, aluminum tri-s-butoxide, and aluminum tri-t-butoxide. Of these, titanium tetraisopropoxide and titanium tetra-n-butoxide are particularly suitable because they have appropriate reactivity and are advantageous for increasing the refractive index.

  In addition, an oligomer soluble in an organic solvent prepared by partial condensation of one or more of these metal alkoxides simultaneously with hydrolysis can also be used favorably for achieving a high refractive index. The conditions for the hydrolysis partial condensation reaction are not particularly limited, but typical conditions include the following. The amount of water used for hydrolysis is preferably 1 to 2 moles, more preferably 1 to 1.7 moles per mole of metal alkoxide. Moreover, reaction temperature is -20-90 degreeC, More preferably, it is -5-50 degreeC, More preferably, it is the range of 0-20 degreeC. The hydrolysis partial condensation reaction is preferably performed in an organic solvent.

  Examples of the organic solvent include alcohol solvents such as methanol, ethanol, isopropanol, and butanol; tetrahydrofuran, 1,4-dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl Ether solvents such as ether; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; aprotic polar solvents such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone; halogen solvents such as dichloromethane and chloroform, toluene and xylene One type or two or more types selected from aromatic solvents such as Particularly preferred solvents are alcohol solvents such as methanol, ethanol, isopropanol and butanol, and tetrahydrofuran.

  In the hydrolysis partial condensation reaction, an acid catalyst selected from hydrochloric acid, sulfuric acid, nitric acid, formic acid and the like, and a base catalyst such as ammonia and amine can be used in combination. The usage-amount of a catalyst is 0.001-0.5 mol with respect to 1 mol of metal alkoxides, More preferably, it is 0.01-0.2 mol, More preferably, it is the range of 0.05-0.2 mol. The reaction time required for the hydrolysis partial condensation is 0.1 to 30 hours, more preferably 0.2 to 10 hours, and further preferably 0.2 to 5 hours, although it depends on the type and amount of the catalyst used. . (B) As a component, the compound marketed as a metal alkoxide oligomer or a polymer can also be used. For example, a polymer of titanium tetraisopropoxide or titanium tetra n-butoxide commercially available as a titanium polymer from Nippon Soda Co., Ltd. is preferably used.

<(C) component>
(C) Water is added in order to cause hydrolysis reaction with the alkoxysilyl group of the component (A) to change a part or all of the alkoxysilyl group into a silanol group. And the hardened | cured material of this invention is obtained by hydrolyzing and condensing the alkoxysilyl group of (A) component and the silanol group produced | generated as mentioned above with (B) component.
Under the present circumstances, it is preferable that the addition amount of the (C) water with respect to (A) component shall be 1-3 mol with respect to 1 mol of alkoxysilyl groups in (A) component.

  For the purpose of promoting the hydrolysis reaction of the alkoxysilyl group, an acid catalyst selected from hydrochloric acid, sulfuric acid, nitric acid, formic acid and the like, and a base catalyst such as ammonia and amine can be used in combination. The usage-amount of a catalyst is 0.001-0.5 mol with respect to 1 mol of alkoxy silyl groups, More preferably, it is 0.01-0.2 mol, More preferably, it is the range of 0.05-0.2 mol. Although the reaction temperature and reaction time depend on the type and amount of catalyst used, the reaction temperature is in the range of -20 to 90 ° C, more preferably -5 to 50 ° C, and still more preferably 0 to 20 ° C. Is in the range of 0.1 to 30 hours, more preferably 0.2 to 10 hours, still more preferably 0.2 to 5 hours. This reaction can be carried out in the absence of a solvent, or can be carried out continuously in the solvent used in the preparation of component (A).

The curable epoxy resin composition of the present invention comprises the above component (A), component (B), and (C) water as essential components. The mixing method of the components (A) to (C) is not particularly limited, but the alkoxysilyl group of the component (A) and (C) water are reacted in advance to form a silanol group by hydrolysis, and then the component (B) Are preferably mixed.
As described above, the component (B) is added to the mixture of the component (A) and the component (C), and hydrolysis condensation is performed between the alkoxysilyl group or silanol group of the component (A) and the component (B). To obtain a cured product. At this time, a condensation catalyst such as dibutyltin dilaurate, dibutyltin diacetate or dioctyltin dilaurate can be added for the purpose of promoting condensation. The reaction is carried out at 20 to 200 ° C., preferably 50 to 150 ° C., more preferably 50 to 100 ° C., and 1 to 100 hours, preferably 2 while removing water, alcohol and remaining solvent generated by the condensation reaction. Cure in the range of ~ 50 hours. Although there is no restriction | limiting in the hardening method, For example, it shape | molds to a predetermined shape by methods, such as coating, casting, and potting, and can heat-harden by oven, a hot press, etc.

  The amount of the component (B) used relative to the component (A) can be set within a wide range, and the refractive index after curing can be widely controlled according to the amount of the component (B) used. However, in consideration of the balance with other physical properties, the amount of component (B) used is 5 to 50% by mass, preferably 5 to 40% by mass, and more preferably in terms of the mass of the metal oxide in the cured product. It controls so that it may become 10-30 mass%. If the amount of the metal oxide is less than 5% by mass, the effect of improving the refractive index is insufficient, and if it exceeds 50% by mass, the mechanical properties are lowered or the transparency is impaired.

In the cured product of the present invention, Si in the component (A) is formed from the component (B) by forming a Si-OM bond with the metal M (M = Ti, Zr, Al) of the component (B). It is presumed that the metal oxide that performs the function of uniformly and stably dispersing in the component (A) gives a cured product having excellent transparency. The formation of this Si-OM bond can be traced by an analytical method such as solid ²⁹ Si-NMR or FT-IR. Moreover, the size of the domain considered that the metal oxide derived from the component (B) is formed in the cured product can be observed using a transmission electron microscope (TEM), and is preferably 500 nm or less from the viewpoint of transparency. Is preferably 50 nm or less, more preferably 20 nm or less.

  In addition to the components (A) to (C), other components can be used in combination with the curable epoxy resin composition of the present invention. For example, in reacting the components (A) to (C), other silanes include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrisilane. Methoxysilane, propyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, cyclopentyltrimethoxysilane, cyclopentyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxy Silane, dimethyldiethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, methylphenyldimethoxysilane, methyl Phenyl diethoxy silane, can be used in combination methylcyclohexyldimethoxysilane, methylcyclohexyl diethoxy silane, methyl cyclopentyl dimethoxysilane, methyl cyclopentyl distearate silane, and their partial condensation products. In particular, tetramethoxysilane, tetraethoxysilane, and partial condensates thereof can be suitably used.

  When obtaining the cured product of the present invention, an epoxy resin curing agent can be used in combination with the curable epoxy resin composition comprising the components (A) to (C). In particular, when the component (A) is prepared so that the epoxy group of the component (a-1) is excessive with respect to the component (a-2), the epoxy group remaining in the component (A) The mechanical properties of the cured product can be further improved by reacting the epoxy resin curing agent. The curing agent is not limited as long as it is usually used for epoxy resins. In addition, the curing agent generally includes those used in combination with a curing agent as a curing accelerator. This curing accelerator plays a role of accelerating the reaction of the curing agent by adding a catalytic amount.

Specific examples of the compound used as the curing agent include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, 4,4′-diaminodiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, Amine-based curing agents such as diaminodiphenylsulfone, m-xylenediamine, m-phenylenediamine, isophoronediamine, 1,3-bis (aminomethyl) cyclohexane, N-aminoethylpiperazine, dicyandiamide; bisphenol A, bisphenol F, bisphenol S , Biphenol, tetramethylbiphenol, hydroquinone, methylhydroquinone, dimethylhydroquinone, trimethylhydroquinone, resorcinol, methylresorcinol, catechol Phenolic curing agents such as methylcatechol, dihydroxynaphthalene, dihydroxymethylnaphthalene, dihydroxydimethylnaphthalene, trishydroxyphenylmethane, phenol novolac, cresol novolac; phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, tetrahydrophthalic anhydride Acid, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, 3,6-endomethylenetetrahydrophthalic anhydride, methyl-3,6-endomethylenetetrahydrophthalic anhydride. Acid anhydride curing agents such as dodecenyl succinic anhydride and trialkyltetrahydrophthalic anhydride; 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1 Imidazole compounds such as cyanoethyl-2-undecylimidazole and 1-cyanoethyl-2-phenylimidazole and salts thereof; 1,8-diaza-bicyclo [5.4.0] -7-undecene, triethylenediamine, 2, 4,6-Tris ( Tertiary amines such as methylaminomethyl) phenol, 2- (dimethylaminomethyl) phenol, benzyldimethylamine, triethanolamine, dimethylaminoethanol and their salts; tributylphosphine, methyldiphenylphosphine, triphenylphosphine, tris (dimethoxy) An organic phosphine compound such as phenyl) phosphine; composed of at least one cation selected from sulfonium, iodonium, diazonium, ammonium and the like, and at least one anion selected from BF ₄ ⁻ , PF ₆ ⁻ , and SbF ₆ ^—. Onium salt-based epoxy group ring-opening polymerization catalysts and the like, and these may be used alone or in combination of two or more. Among these, an acid anhydride curing agent is particularly suitable for obtaining a cured epoxy resin excellent in transparency and can be suitably used. Cationic polymerization catalysts such as 2-butenyltetramethylenesulfonium hexafluoroantimonate and 3-methyl-2-butenyltetramethylenesulfonium hexafluoroantimonate can also be used favorably.

  The curable epoxy resin composition of the present invention includes an antioxidant, a stabilizer, a reactive or non-reactive diluent, a plasticizer, a release agent as long as the effects of the present invention are not impaired as necessary, in addition to the components described above. Molding agents, flame retardants, pigments, colorants, phosphors and the like can be added. Also, fillers such as silica (fumed silica, colloidal silica, precipitated silica, etc.) and glass can be added for the purpose of improving various physical properties such as coefficient of thermal expansion, hardness, and thixotropy. Glass can be used without being limited to a shape such as short fiber, long fiber, woven fabric, and non-woven fabric. The type is not limited to E glass, T glass, D glass, NE glass and the like.

  The refractive index of the cured product of the present invention is desirably 1.59 or more at a wavelength of 589.3 nm. The cured product of the present invention makes use of its transparency and high refractive index, such as eyeglass lenses, optical equipment lenses, CD and DVD pickup lenses, automotive headlamp lenses, projector lens lenses, LED, etc. It is suitably used for various optical members such as a sealing material, an optical fiber, an optical waveguide, an optical filter, an optical adhesive, an optical disk substrate, a display substrate, and a coating material such as an antireflection film.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.
The physical properties were measured by the methods described below.
(1) Follow-up of addition reaction It was carried out by measuring a ¹ H-NMR spectrum using a Fourier transform nuclear magnetic resonance analyzer (manufactured by JEOL Ltd., JNM-GSX). The magnetic field strength is 400 MHz and the number of integration is 32 times. Deuterated chloroform (CDCl ₃ ) was used as a measurement solvent, and tetramethylsilane (TMS) was used as an internal standard substance.

(2) Follow-up of curing reaction by hydrolysis condensation It was performed by measuring IR spectrum by KBr method using a Fourier transform infrared spectroscopic analyzer (Perkin Elmer, SPECTRUM2000).

(3) Refractive index measurement Measurement was performed using an Abbe refractometer (NAGO-2T, manufactured by Atago Co., Ltd.). Na light monochromatic light (589.3 nm) was used as a light source, and methylene sulfur iodide (n _D = 1.78) was used as an intermediate solution between the test piece and the prism. As the test piece, a cured product was cut into 8 × 20 × 3 mm rectangular parallelepiped pieces, polished with water-resistant abrasive paper No. 2000, and further polished with alumina.

(4) Observation with Transmission Electron Microscope (TEM) A transmission electron microscope (JEM-1210, manufactured by JEOL Ltd.) was used to observe the phase structure of the cured product. Using an ultramicrotome (REICAT ULTRACUT E, manufactured by Leica Co., Ltd.) and a diamond knife (Sumitomo Electric Co., Ltd., SUMI KNIFE SK1045), an ultra-thin film piece having a thickness of 50 nm was prepared. And observed.

[Example 1]
(1) Synthesis of alkoxysilyl group-modified epoxy resin In a glove box, 10.0 parts by mass of 3-mercaptopropyltrimethoxysilane with 10.0 parts by mass of bisphenol A type epoxy resin (Japan Epoxy Resin Co., Ltd., MW = 380) And 0.41 part by mass of dimethylbenzylamine were added and stirred at 60 ° C. An exotherm accompanying the denaturation reaction was observed, and stirring was continued for 1 hour until the exotherm disappeared.
When FT-IR was measured to confirm the structure of the obtained mercaptosilane-modified epoxy resin, the peak of the stretching vibration of the epoxy group appearing at 4530 cm ⁻¹ and the peak of the stretching vibration of the —SH group appearing at 2568 cm ⁻¹ were found. It was confirmed that it had disappeared completely. Also in ¹ H-NMR measurement, it was confirmed that the peaks of —SH group (1.35 ppm) and tertiary hydrogen of the epoxy group (3.35 ppm) disappeared, and the epoxy group and mercapto group were quantitatively determined. It turns out that it is reacting. Furthermore, it was found that the methoxy group derived from 3-mercaptopropyltrimethoxysilane remained unreacted.

(2) Preparation and curing of curable epoxy resin composition Based on 1 mol of the mercaptosilane-modified epoxy resin prepared in (1) above, 6 mol of water, 0.4 mol of hydrochloric acid (HCl), and 14.8 mol of isopropanol were added. The mixture was stirred at room temperature for 5 seconds. Subsequently, 0.012 mol of dibutyltin dilaurate and 1.05 mol of titanium tetraisopropoxide (amount in which the theoretical content of titanium in the cured product is 9.0% by mass in terms of titanium oxide (TiO ₂ )) were added, and Stir for 5 seconds. The obtained solution was placed in a mold and allowed to stand at atmospheric pressure for 2 days to remove volatile components, and then reacted in a constant temperature bath at 80 ° C. for 48 hours to obtain a cured product having a thickness of about 2 mm. This cured product was excellent in transparency without coloring.

(3) Analysis of cured product FT-IR of the cured product obtained in (2) above was measured, and absorption of 1034 cm ⁻¹ derived from Si—O—Si bond and 920 cm ⁻ derived from Si—O—Ti bond. Absorption of ¹ was confirmed. Moreover, when TEM observation of the cured product was performed, a domain structure considered to be an aggregation of inorganic components was not observed, and a uniform structure was confirmed. It was presumed that the formation of Si—O—Ti bonds made titanium uniformly compatible in the system, and excellent transparency was obtained.

[Examples 2 and 3]
According to the same procedure as in Example 1, titanium tetraisopropoxide was added and cured so that the theoretical content of titanium was 2.8 and 5.2% by mass in terms of titanium oxide (TiO ₂ ), respectively. All of the obtained cured products were not colored and excellent in transparency.

[Comparative Example 1]
In Example 1, titanium tetraisopropoxide was not used, and only mercaptosilane-modified epoxy resin was hydrolyzed and condensed and cured.
The refractive indexes of the cured products obtained in Examples 1 to 3 and Comparative Example 1 are summarized in Table 1. It can be seen that by using the method of the present invention, a high refractive index can be imparted while maintaining the transparency of the cured product.

[Comparative Examples 2 to 4]
A conventional method of combining titanium tetraisopropoxide in a cured product composed of an epoxy resin and an epoxy resin curing agent was studied.
In a glove box filled with nitrogen, a chemical equivalent of tetraethylenepentamine and titanium tetraisopropoxide in bisphenol A type epoxy resin (Japan Epoxy Resin Co., Ltd., MW = 380) in terms of titanium oxide (TiO ₂ ). , 6.0% by mass (Comparative Example 3) and 10.0% by mass (Comparative Example 4), and stirred at 70 ° C. under reduced pressure until uniform. A mixture without addition of titanium tetraisopropoxide was also prepared at the same time (Comparative Example 2). The obtained mixture was poured between glass plates with a spacer having a thickness of 3.2 mm, and cured under reduced pressure at 70 ° C. for 4 hours, normal pressure at 100 ° C. for 4 hours, and 150 ° C. for 4 hours. Thereafter, post-curing was further performed at 190 ° C. under reduced pressure for 4 hours to obtain a cured product.

  The measurement results of the refractive index of the obtained cured product are summarized in Table 1. The results of Table 1 are shown as a graph in FIG. As is apparent from FIG. 1, the method of the present invention combining an epoxy resin modified with 3-mercaptopropyltrimethoxysilane and a titanium alkoxide combines titanium alkoxide in a cured product composed of an epoxy resin and an epoxy resin curing agent. It can be seen that it is advantageous to obtain a high refractive index as compared with the conventional method.

[Comparative Examples 5 and 6]
The procedure of Example 1 was repeated using 3-aminopropyltrimethoxysilane instead of 3-mercaptopropyltrimethoxysilane. However, gelation occurred before addition of titanium tetraisopropoxide, and titanium tetraisopropoxide could not be uniformly mixed.
As described above, it was found that a cured product having excellent transparency and high refractive index can be obtained by combining an epoxy resin modified with 3-mercaptopropyltrimethoxysilane and titanium alkoxide.

  The curable epoxy resin composition and the cured product of the present invention are used for spectacle lenses, optical equipment lenses, CD and DVD pickup lenses, automobile headlamp lenses, and projectors, taking advantage of its transparency and high refractive index. Suitable for various optical members such as lens materials such as lenses, sealing materials such as LEDs, optical fibers, optical waveguides, optical filters, optical adhesives, optical disk substrates, display substrates, anti-reflection coatings, etc. .

It is a figure which shows the relationship between the refractive index of the hardened | cured material obtained by the Example and the comparative example, and titanium oxide content.

Claims (5)

Obtained by reacting the epoxy group of the epoxy resin (a-1) with a silane compound (a-2) having simultaneously one mercapto group and at least one alkoxy group bonded to a silicon atom in one molecule. alkoxysilyl group-modified epoxy resin (a), the titanium alkoxide, and zirconium alkoxy least one metal alkoxide and / or a hydrolysis partial condensation product selected from de by Li Cheng group (B), an essential component (C) water And the usage-amount of the said (B) component with respect to the said (A) component is an quantity from which the content of the metal derived from the said metal alkoxide will be 5-50 mass% in conversion of the metal oxide in hardened | cured material. Curable epoxy resin composition.   Hardened | cured material obtained by hardening the curable epoxy resin composition of Claim 1 by the process including a hydrolysis-condensation reaction. Cured product of claim 2 Symbol placement refractive index at a wavelength of 589.3nm is characterized in that 1.59 or more. An optical member comprising a cured product according to claim 2 or 3. By reacting the epoxy group of the epoxy resin (a-1) with a silane compound (a-2) having simultaneously one mercapto group and at least one alkoxy group bonded to a silicon atom in one molecule, alkoxysilyl process of manufacturing a group-modified epoxy resin (a), and the (a) and at least one metal alkoxide and / or a hydrolysis partial condensation product selected from titanium alkoxides and zirconium alkoxy de by Li Cheng group (B) and water (C) viewed including the step of hydrolytic condensation reaction under the coexistence of the (a) wherein for component (B) the amount of the component, the metal of the metal alkoxide content of the metal derived from the in the cured product The manufacturing method of the hardened | cured material which is the quantity used as 5-50 mass% in conversion of an oxide .

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