JP2003292924A - Adhesive for optical device and optical device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive for an optical device, capable of preventing peeling at the interface between the adhesive and an optical element caused by thermal expansion and shrinkage, and providing good adhesion and thermal shock resistance to the optical element even in a high-temperature and high- humidity condition, or a temperature-cycling condition. <P>SOLUTION: The adhesive for the optical device is used for sticking the optical element to a base plate, and comprises (A) a liquid epoxy resin, (B) an inorganic filler having ≤1 wt.% content of particles with ≥45 μm particle diameters, and 1-20 μm average particle diameter. The content of the inorganic filler is 20-90 wt.% based on the whole composition. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device adhesive suitable for adhering optical elements such as optical isolators used in optical communication systems and optical measuring instruments, and an optical device using the same.

[0002]

2. Description of the Related Art When light from a light source is transmitted through an optical system, the light reflected by the end surface of the optical system returns to the light source. For example, in signal transmission by optical fiber, the light emitted from the laser light source is projected on the end face of the fiber through the lens, and most of it enters the fiber as transmitted light, but part of it is surface reflected by the end face of the lens or fiber. Then, it returns to the laser light source and disturbs the emission of the laser to generate noise. Conventionally, an optical isolator has been used to eliminate such noise.

An example of the optical isolator is shown in FIG. The optical isolator is used by inserting a joined body in which a polarizer 2 and an analyzer 3 are joined to the Faraday element 1 with adhesives 4 and 4 into a cylindrical magnet 5.

However, in recent years, it has been required to improve the durability of each optical component of the optical isolator under high temperature and high humidity, and a joining technique capable of withstanding the high temperature and high humidity of each optical component is required. There is.

This is because when the bondability is poor, the assembled optical parts are subjected to a thermal shock test of −45 to 85 ° C. or 85 ° C./85.
This is because the adhesive layer deteriorates during long-term storage at% RH, the optical axis of the light emitted from the optical isolator shifts, and the coupling loss of the optical fiber increases when incorporated as a semiconductor module. In the worst case, the bond may be broken.

On the other hand, in order to obtain the reliability of the bonding of the optical element, it is necessary to perform metallization for solder bonding on the entire surface of the optical element other than the light-transmitting portion, or to perform metal bonding, or to fix the low melting point glass. However, since both of them have complicated processes, the yield is poor and the cost is high, which is a problem.

The present invention has been made to improve the above circumstances, and an adhesive for an optical device, which gives good adhesiveness and impact resistance even under high temperature and high humidity conditions and temperature recycling conditions, and the same. It is an object to provide a highly reliable optical device used.

[0008]

Means for Solving the Problems and Modes for Carrying Out the Invention As a result of extensive studies conducted by the present inventor to achieve the above object, (A) a liquid epoxy resin and (B) a particle size of 45 μ
The content of the particles of m or more is 1% by weight or less, and the average particle size of the inorganic filler is more than 1 μm and 20 μm or less, and the content of the inorganic filler is 20 to 90 of the entire composition.
It was found that by using a liquid epoxy resin composition in an amount of wt% as an adhesive, the adhesive performance for crystal materials such as a polarizer and an analyzer is improved, and an optical device such as a highly reliable optical isolator can be obtained. It was

In this case, spherical silica is particularly preferably used as the inorganic filler, but since the optical element is extremely fine, if a large amount of large particles are contained, the levelness of the element cannot be maintained. , It was found that it could not penetrate into the narrow gap and adversely affected the reliability of the optical device. On the other hand, it is possible to satisfactorily penetrate into narrow gaps by using an inorganic filler having a particle size of 45 μm or more of 1% by weight or less and an average particle size of more than 1 μm and controlled to 20 μm. Found.

Further, by allowing the inorganic filler to be present in the above liquid epoxy resin composition in the above-mentioned particle size control and compounding amount, the expansion / shrinkage degree is reduced by the effect of the inorganic filler, and Interfacial peeling from an optical element due to thermal expansion and contraction during a thermal shock test at 85 ° C. can be prevented. As a result, by using the liquid epoxy resin composition of the present invention, thermal shock resistance is improved and adhesion to an optical element is achieved. It was found that the elasticity is lowered by the effect of silicone and the above effect is more effectively achieved by further improving the property, and further by compounding a silicone-modified resin,
The present invention has been completed.

Therefore, the present invention is an adhesive for adhering an optical element to a substrate, which comprises (A) a liquid epoxy resin,
And (B) the content of particles having a particle size of 45 μm or more is 1% by weight.
A liquid epoxy resin composition containing an inorganic filler having an average particle size of 1 μm or more and 20 μm or less, and the content of the inorganic filler is 20 to 90% by weight of the entire composition, An adhesive for optical devices, which preferably further contains a silicone-modified resin, and an optical device obtained by adhering an optical element to a substrate using this adhesive are provided.

The present invention will be described in more detail below.
The epoxy resin of the component (A) used in the present invention is not particularly limited in molecular structure, molecular weight and the like as long as it has two or more epoxy groups in one molecule, and for example, bisphenol A type epoxy resin, Bisphenol type epoxy resin such as bisphenol F type epoxy resin, alicyclic epoxy resin, phenol novolac type epoxy resin, novolac type epoxy resin such as cresol novolac type epoxy resin, triphenol methane type epoxy resin, triphenol propane type epoxy resin, etc. Triphenol alkane type epoxy resin, phenol aralkyl type epoxy resin, biphenyl aralkyl type epoxy resin, stilbene type epoxy resin, naphthalene type epoxy resin,
Examples thereof include biphenyl type epoxy resin and cyclopentadiene type epoxy resin. These epoxy resins may be used alone or in combination of two or more. Of these, a liquid epoxy resin at room temperature (for example, 25 ° C.) is desirable. Further, it is particularly preferable to use a bisphenol type epoxy resin such as a bisphenol A type epoxy resin or a bisphenol F type epoxy resin. Further, an epoxy resin having the following structure can also be preferably used.

[0013]

[Chemical 4]

The total chlorine content in the epoxy resin of the present invention is preferably 1,500 ppm or less, particularly 1,000 ppm or less. Also, the extracted water chlorine in 100 hours at 50% epoxy resin concentration for 20 hours has a chlorine content of 10 pp.
It is preferably m or less. Total chlorine content is 1,50
When it exceeds 0ppm, or chlorine in extracted water is 10pp
If it exceeds m, it may adversely affect the reliability of the optical device, especially the moisture resistance.

In the present invention, various conventionally known inorganic fillers are added as the component (B) for the purpose of reducing the expansion coefficient. As the inorganic filler, fused silica,
Crystalline silica, alumina, boron nitride, aluminum nitride, silicon nitride, magnesia, magnesium silicate and the like are used. Here, the average particle size is more than 1 μm and 20 μm or less, preferably 1
The content of the particles having a particle size of 45 μm or more and 1 μm or less, preferably 0.5 wt% or more
It is the following. If the average particle size exceeds 20 μm, resistance to flow increases, and if the content of particles with a particle size of 45 μm or more exceeds 1% by weight, the levelness of the device cannot be maintained and reliability is affected. . When the average particle size is 1 μm or less, when the inorganic filler is contained in an amount of 20% by weight or more, the adhesive becomes highly viscous, and thus the function as a liquid is deteriorated. The average particle size and the particle size can be obtained, for example, by measuring the particle size distribution by a laser light diffraction method, and the average particle size can be obtained as, for example, a weight average value (or median size).

The content of the inorganic filler is 20 to 90% by weight of the whole liquid epoxy resin composition, and preferably 40.
The range of -80 wt% is preferred. Below 20% by weight,
It has a large expansion coefficient and induces peeling from the element in the cold heat test, and when it exceeds 90% by weight, the viscosity becomes high and the function as a liquid is deteriorated.

The liquid epoxy resin composition may be blended with silicone rubber, silicone oil or liquid polybutadiene rubber for the purpose of reducing stress. In particular, it is preferable to add a silicone-modified resin as the component (C). As the silicone-modified resin, an alkenyl group of an alkenyl group-containing epoxy resin and / or an alkenyl group-containing phenol resin and the following average formula (1) H _a R _b SiO 2 _{(4-ab) / 2} (1) (wherein, R is A substituted or unsubstituted monovalent hydrocarbon group, a is 0.005-0.1, b is 1.8-2.2, provided that a +
The range of b is 1.81 ≦ a + b ≦ 2.3, preferably a is 0.01 to 0.05, b is 1.9 to 2.0, and 1.91 ≦.
a + b ≦ 2.05. Of the organopolysiloxane having 20 to 400, preferably 40 to 200, and 1 to 5, preferably 2 to 4, particularly 2 and particularly 2 SiH groups in one molecule. It is desirable to incorporate a copolymer obtained by addition reaction with SiH groups, that is, a silicone-modified epoxy resin and / or a silicone-modified phenol resin.

As the monovalent hydrocarbon group for R, one having 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms is preferable, and a methyl group,
Alkyl group such as ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, hexyl group, cyclohexyl group, octyl group, decyl group, vinyl group, allyl group, propenyl group, butenyl group, hexenyl group Such as alkenyl groups, phenyl groups, xylyl groups, tolyl groups, and other aryl groups, benzyl groups, phenylethyl groups, phenylpropyl groups, and other aralkyl groups, and the hydrogen atoms of these hydrocarbon groups. A chloromethyl group substituted with a halogen atom such as fluorine or bromine,
Examples thereof include halogen-substituted monovalent hydrocarbon groups such as bromoethyl group and trifluoropropyl group.

When the above copolymer is blended, it is contained in an amount of 1 to 30% by weight based on the total weight of the organic resin components (that is, liquid epoxy resin, curing agent as an optional component described below, and copolymer). By compounding it, the stress can be reduced. As this copolymer, those represented by the following formula (2) or formula (3) are particularly preferable.

[0020]

[Chemical 5] (In the formula, R ¹ is a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group, an alkoxy group or an alkoxyalkyl group, R ² is a substituted or unsubstituted monovalent hydrocarbon group, and R ³ is a hydrogen atom or a glycidyl group. , R ⁴ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and R ⁵ represents a substituted or unsubstituted divalent hydrocarbon group, and n, p and q are integers of 0 or more.)

In the above formula (2), R ¹ is preferably a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having about 1 to 6 carbon atoms, an alkoxy group or an alkoxyalkyl group. For example, hydrogen atom, alkyl group such as methyl group, ethyl group, propyl group, butyl group, alkenyl group such as vinyl group, allyl group, isopropenyl group, aryl group such as phenyl group, methoxy group, ethoxyethyl group, etc. An alkoxy group and an alkoxyalkyl group are particularly preferable, and R ² is an unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably about 1 to 8 carbon atoms, similar to those exemplified in the above R. Preferably, R ⁵ is —CH ₂ CH ₂ CH ₂ —,
_{-OCH 2 -CH (OH) -CH 2} -O-CH 2 CH 2 CH
₂ - or -O-CH ₂ CH ₂ CH ₂ - oxygen atoms represented by like, is preferably a non-substituted or substituted divalent hydrocarbon group such as alkylene group which may contain a hydroxyl group. Further, p, q, and n are integers of 0 or more, but p is 1 to 5
0 is an integer, q is an integer of 1 to 50, n is preferably an integer of 1 to 200, and particularly p is 1 to 10 and q is 1 to 1.
It is preferable that 0 and n are 9 to 100. In the formula (3), R ³ is a hydrogen atom or a glycidyl group, R ⁴ is a hydrogen atom, a methyl group or a trifluoromethyl group, and R
² , R ⁵ and n are the same as above.

In this case, it is preferable that the silicone-modified epoxy resin (C-1) and the silicone-modified phenol curing agent (C-2) are used in combination as the silicone-modified resin (C).

Here, the silicone-modified epoxy resin of the component (C-1) is preferably represented by the formula (4).

[0024]

[Chemical 6] (In the formula, R ¹¹ represents a glycidyl group, R ¹² represents a hydrogen atom, or an unsubstituted or substituted monovalent hydrocarbon group, R ¹³ represents a divalent hydrocarbon group, and r represents an integer of 0 or more.)

Here, the glycidyl group of R ¹¹ is represented by the following formula.

[Chemical 7]

R ¹² may be the same or different and each is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group. Specifically, the monovalent hydrocarbon group has 1 to 10 carbon atoms, In particular, 1 to 8, for example, an alkyl group such as a methyl group and an ethyl group, an alkenyl group such as a vinyl group and an allyl group, an aryl group such as a phenyl group, and a part of hydrogen atoms bonded to carbon atoms of these groups Or the thing which substituted all the halogen atoms, such as a fluorine atom, and a cyano group, is mentioned. R ¹² is particularly preferably a hydrogen atom, a methyl group, a trifluoropropyl group or the like. R ¹³ is preferably 1
To 5, especially 1 to 3 divalent hydrocarbon groups such as alkylene groups. r is an integer of 0 or more, preferably 0 to 60, more preferably 10 to 40, further preferably 10 to 20, and a liquid one is preferable.

The content of the component (C-1) in the organic resin components [(A), (C-1), (C-2) component] is preferably 10 to 50% by weight, and particularly 25. ~ 4
0% by weight is preferred.

Further, the silicone-modified phenol curing agent as the component (C-2) is preferably represented by the following formula (5).

[0029]

[Chemical 8] (In the formula, s is an integer of 0 or more, preferably 10 to 4
It is an integer of 0. )

The content of the component (C-2) in the organic resin component is an effective amount for curing the components (A) and (C-1), and is usually (A) and (C-1). , (C-
2) 10 to 70% by weight, especially 30 to
It is preferably 60% by weight.

In the above components (C-1) and (C-2), the molecular weight of these organopolysiloxane moieties is not particularly limited, but it is 100 to 10,0.
00, especially 500 to 5,000 is desirable. When the molecular weight of the organopolysiloxane portion is 100 to 10,000, the cured product of the silicone-modified resin is uniform without phase separation, and the characteristics of the silicone resin are excellent in flexibility and impact resistance, and the adhesiveness and heat resistance. It is possible to combine the characteristics of epoxy resin and phenol resin, which have excellent properties and moisture resistance. Here, if the molecular weight is less than 100, the cured product may be rigid and brittle, and if the molecular weight is more than 10,000, phase separation may occur.

In this way, (C-1), (C-2)
When the components are used in combination, the component (A) is preferably a bisphenol type epoxy resin, and the liquid epoxy resin as the component (A) is an organic resin component (that is, the liquid epoxy resin as the component (A) and the above-mentioned component). The content of the silicone-modified epoxy resin as the component (C-1) and the silicone-modified phenol curing agent as the component (C-2) is preferably 5 to 50% by weight, and more preferably 20 to 30% by weight. If it is less than 5% by weight, the adhesive strength may be low and the optical component may be peeled off. If it exceeds 50% by weight,
There is a risk that cracks may occur during curing shrinkage.

When the liquid epoxy resin composition of the present invention contains a silicone-modified phenol resin such as the above-mentioned component (C-2), the liquid epoxy resin can be cured by this. When the silicone-modified phenolic resin is not blended, the liquid epoxy resin can be cured by the curing accelerator described later, and a curing agent is not particularly required (that is, a self-polymerizing composition), but it is necessary in some cases. According to the above, a curing agent may be further compounded (that is, as a phenol resin curing type, acid anhydride curing type, amine curing type composition, etc.) and cured.

The curing agent as an optional component used in the present invention has two or more functional groups capable of reacting with the epoxy group in the liquid epoxy resin (for example, phenolic hydroxyl group, amino group, acid anhydride group, etc.). As long as it is a compound having one or more acid anhydride groups, the molecular structure, molecular weight and the like are not particularly limited, and known compounds can be used. For example, as a phenol resin other than the above silicone-modified phenol resin, a phenol resin having at least two phenolic hydroxyl groups in one molecule, specifically, a novolac-type phenol resin such as phenol novolac resin and cresol novolac resin, para-xylylene-modified novolac. Resin, metaxylylene-modified novolac resin, xylylene-modified novolac resin such as ortho-xylylene-modified novolac resin, bisphenol A type resin, bisphenol F type resin or other bisphenol type phenol resin, biphenyl type phenol resin, resole type phenol resin, phenol aralkyl type resin , Biphenylaralkyl type resins, triphenolmethane type resins, triphenolpropane type resins and other triphenolalkane type resins and polymers thereof. Nord resins, naphthalene ring-containing phenolic resins, either phenol resins such as dicyclopentadiene-modified phenolic resins can be used.

When the liquid epoxy resin composition is hardened by blending the above-mentioned curing agent, the blending amount is an effective amount to harden the epoxy resin and is appropriately selected. In the case of a phenol resin, the epoxy resin is used. Phenolic OH contained in the curing agent per 1 mol of epoxy group contained in
The molar ratio of the groups is preferably 0.5 to 1.5.

As the curing agent, amine type and acid anhydride type curing agents can be used in addition to the phenol resin.

Examples of the acid anhydrides include tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methylhymic acid anhydride, pyromet acid dianhydride, 3,4-
Dimethyl-6- (2-methyl-1-propenyl) -4-
Cyclohexane-1,2-dicarboxylic acid anhydride, 1-methyl-4- (1-methylethyl) -bicyclo [2.2.
2] Oct-5-ene-2,3-dicarboxylic acid anhydride,
Maleated alloocimene, benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4 -Dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride and the like, preferably having 1 or 2 aliphatic or aromatic rings in the molecule Together with an acid anhydride group (that is, -CO-O-CO-
An acid anhydride having 1 or 2 groups) and having 4 to 25 carbon atoms, preferably about 8 to 20 carbon atoms is suitable.

When an acid anhydride is used as the curing agent, the molar ratio of the carboxylic acid group derived from the acid anhydride group in the curing agent is 0.5 with respect to 1 mole of the epoxy group in the epoxy resin.
It is suitable to be in the range of from 1.5 to 1.5. If it is less than 0.5, the curability may be insufficient, and if it exceeds 1.5, unreacted acid anhydride may remain and the glass transition temperature may decrease. It is more preferable to set it in the range of 0.8 to 1.2.

Alternatively, for the same reason as above, the molar ratio of the acid anhydride group in the acid anhydride to 1 mol of the epoxy group in the epoxy resin is preferably 0.3 to 0.7, more preferably 0. You may mix | blend so that it may become the range of 0.4-0.6. If the amount is less than 0.3 mol, the curability may be insufficient, and if it exceeds 0.7 mol, the unreacted acid anhydride may remain and the glass transition temperature may decrease.

In addition to the above, carboxylic acid hydrazides such as dicyandiamide, adipic acid hydrazide and isophthalic acid hydrazide can be used as the curing agent.

Further, in the composition of the present invention, curing is accelerated in order to cure the liquid epoxy resin as the component (A) or to accelerate the curing reaction between the liquid epoxy resin and a curing agent which is an optional component. Agents can be added. The curing accelerator is not particularly limited as long as it accelerates the curing reaction, and for example, one kind or two or more kinds selected from an imidazole compound, a tertiary amine compound and an organic phosphorus compound can be blended.

Specific examples of the imidazole compound include 2
-Methylimidazole, 2-ethylimidazole, 2-
Undecyl imidazole, 2,4-dimethyl imidazole, 2-heptadecyl imidazole, 1,2-dimethyl imidazole, 1,2-diethyl imidazole, 2-phenyl-4-methyl imidazole, 2,4,5-triphenyl imidazole , 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2-
Phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-benzyl-2-methylimidazole, 2
-Phenyl-4,5-dihydroxymethylimidazole, 2-aryl-4,5-diphenylimidazole,
2,4-diamino-6- [2'-methylimidazolyl-
(1) ′]-Ethyl-S-triazine, 2,4-diamino-6- [2′-ethyl-4′-methylimidazolyl-
(1) ′]-Ethyl-S-triazine, 2,4-diamino-6- [2′-methylimidazolyl- (1) ′]-ethyl-S-triazine isocyanuric acid adduct, 2-phenyl-4- Methyl-5-hydroxymethylimidazole and the like can be mentioned. Examples of the imidazole compound include 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole and 2,4-diamino-6- [2'-ethyl-4'-methyl. Imidazolyl- (1) ']-ethyl-S-triazine, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-ethylimidazole, 1,2-dimethylimidazole, 1,2-diethylimidazole, 2,4 -Dimethylimidazole and 2-phenyl-4-methylimidazole are preferred.

As the tertiary amine compound, amine compounds having an alkyl group or an aralkyl group as a substituent bonded to a nitrogen atom such as triethylamine, benzyldimethylamine, benzyltrimethylamine and α-methylbenzyldimethylamine, 1,8 -Diazabicyclo [5.4.0] undecene-7 and its phenolic salts,
Examples thereof include salts of cycloamidine compounds such as octylates and oleates and salts thereof with organic acids, and salts or complex salts of cycloamidine compounds such as compounds of the following formulas and quaternary boron compounds.

[0044]

[Chemical 9]

Further, as the organic phosphorus compound, triphenylphosphine, tributylphosphine, tri (p-
Methylphenyl) phosphine, tri (nonylphenyl)
Examples thereof include triorganophosphine compounds such as phosphine, diphenyltolylphosphine, triphenylphosphine and triphenylborane, and quaternary phosphonium salts such as tetraphenylphosphonium and tetraphenylborate. Among these, those represented by the following general formula (6) are preferable.

[0046]

[Chemical 10] (In the formula, R ⁶ is a hydrogen atom, or an alkyl group or an alkoxy group having 1 to 4 carbon atoms.)

The alkyl group includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, and the like, and the alkoxy group includes a methoxy group, an ethoxy group, and the like. .
R ⁶ is preferably a hydrogen atom or a methyl group.
The following are mentioned as a compound of Formula (6).

[0048]

[Chemical 11]

When a curing accelerator is used, it is not more than 10 parts by weight (that is, 0 to 10 parts by weight), preferably 0.01 to 10 parts by weight, and more preferably 0. It is preferable to add it in the range of 5 to 5 parts by weight. If the addition amount is less than 0.01 parts by weight, the curability may decrease, and if it exceeds 10 parts by weight, the curability may be excellent but the storage stability tends to decrease.

If necessary, the liquid epoxy resin composition of the present invention further contains a surface treatment agent, a carbon functional silane for improving adhesion, a pigment such as carbon black, a dye, an antioxidant, and other additives. be able to. In particular, the surface treatment agent, like the origin of its name, performs the surface treatment of the filler,
Effective in improving wettability with resin.

The liquid epoxy resin composition of the present invention may be prepared by, for example, stirring and dissolving the liquid epoxy resin, the inorganic filler, the curing agent, the curing accelerator and the like at the same time or separately and, if necessary, adding heat treatment. , Mix and disperse. The apparatus for stirring, dissolving, mixing, dispersing and the like used in these operations is not particularly limited, but a lychee machine equipped with a stirring and heating device, three rolls, a ball mill, a planetary mixer and the like can be used. Further, these devices may be combined appropriately. However, when using an acid anhydride as a curing agent, a temperature range that does not reduce the adhesiveness at high temperature,
Particularly, it is preferably 10 to 40 ° C.

The liquid epoxy resin composition thus obtained has a viscosity at 25 ° C. of 100 to 500 Pa.
s, particularly preferably 200 to 400 Pa · s.

The adhesive for optical devices of the present invention comprises this liquid epoxy resin composition. The adhesive of the present invention is, for example, a component of an optical isolator, that is, a Faraday element, a polarizer, an analyzer, and a cylinder. It is used to bond various optical elements such as magnets. Known methods, conditions, etc. can be adopted as the bonding method, bonding conditions, etc., but the curing of the adhesive (liquid epoxy resin composition) of the present invention is 90-200.
It can be carried out at a temperature of 100 ° C., particularly 100 to 150 ° C. The curing time is preferably 1 to 5 hours.

[0054]

The adhesive for optical devices of the present invention can prevent interfacial peeling from the optical element due to thermal expansion and contraction, and has good adhesiveness to the optical element even under high temperature and high humidity conditions and temperature cycles. Provides thermal shock resistance.

[0055]

EXAMPLES The present invention will be specifically described below by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples. In addition, wt% means weight%.

Examples 1 to 5 and Comparative Examples 1 to 5 Bisphenol A type epoxy resin (RE
310: Nippon Kayaku Co., Ltd.) 50 parts by weight, a complex salt of a cycloamidine compound and a quaternary boron compound as a curing accelerator (U
CAT5002: manufactured by Asahi Kasei Co., Ltd.) 1 part by weight, a silicone-modified epoxy resin represented by the following formula in an amount shown in Table 1, and spherical silica having an average particle size shown in Table 1 as an inorganic filler is blended to obtain a uniform mixture. An epoxy resin composition was obtained by kneading.

Using the obtained epoxy resin composition, 5
2 mm × 5 mm × 15 mm prismatic sample at 150 ° C
It was prepared by curing for a time. Then 25-25
The range of 0 ° C. is heated at 5 ° C./min, the glass transition temperature (Tg) by TMA (thermo-mechanical analyzer), and the expansion coefficient at Tg or higher (200 to 230 ° C.) and Tg or lower (50 to 80 ° C.). Was measured. In addition, the end surface is 2 mm x 2 m
The obtained epoxy resin composition was applied to a m × 1 mm prismatic polarizer at a thickness of 10 mg / 4 mm ² and fixed on a glass epoxy resin plate. This sample was cured at 150 ° C. for 2 hours to obtain an adhesion evaluation sample as shown in FIG.

The obtained sample was subjected to a thermal shock test at −45 to 85 ° C. according to Bell-core standard, and the adhesive strength of the sample after 500 cycles was measured. The adhesive strength was measured as a shear strength in a direction of an arrow in FIG. 2 with a push-pull gauge for a cured product having a height of 1 mm from the coated surface by fixing the obtained sample to a measuring device with a fixing jig. . The evaluation results are shown in Table 1.

[0059]

[Table 1]

Silicone-modified epoxy resin

[Chemical 12]

Examples 6 to 10 and Comparative Examples 6 to 8 Bisphenol A type epoxy resin (RE
310: manufactured by Nippon Kayaku Co., Ltd.), 1 part by weight of a complex salt of a cycloamidine compound and a quaternary boron compound (UCAT5002: manufactured by Asahi Kasei Co., Ltd.) as a curing accelerator, and R in the formula (4). Silicone-modified epoxy resin (r = 10) [compound (4)] in which ¹¹ is a glycidyl group, R ¹² is a methyl group, and R ¹³ is a methylene group, the silicone represented by the formula (5) The amount of the compound [compound (5)], which is a modified phenol curing agent (s = 10), shown in Tables 2 and 3, and an average particle diameter of 2.6 μm as an inorganic filler.
m and a spherical silica having a particle diameter of 45 μm or more and a content of 0.008 wt% were mixed in an amount shown in Table 2 and uniformly kneaded to obtain an epoxy resin composition.

Using the obtained epoxy resin composition, 5 m
An m × 5 mm × 15 mm prismatic sample was cured at 150 ° C. for 2 hours to prepare. Next, the range of −150 to 250 ° C. is set to 5 ° C./min. The glass transition temperature (Tg) and Tg or higher (7) by TMA (thermo-mechanical analyzer).
The expansion coefficient was measured at 0 to 120 ° C.) and below Tg (−130 to −80 ° C.).

As shown in FIG. 2, the end surface is 2 mm × 2.
The resin composition 8 thus obtained was applied to a prism 6 having a size of 1 mm × 1 mm and a thickness of 10 mg / 4 mm ² and fixed to a glass epoxy resin plate 7. This sample is 150 ℃
Then, it was cured for 2 hours to obtain a sample for adhesion evaluation as shown in FIG.

The obtained sample was subjected to a thermal shock test at −45 to 85 ° C. according to Bell-core standard, and the adhesive strength of the sample after 500 cycles was measured. The adhesive strength was measured as a shear strength with a push-pull gauge for a cured product having a height of 1 mm from the coated surface by fixing the obtained sample to a measuring device with a fixing jig. The results are shown in Table 4.

[0065]

[Table 2]

[0066]

[Table 3]

[0067]

[Table 4]

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of an optical isolator according to the present invention.

FIG. 2 is a perspective view of an adhesion evaluation sample according to the present invention.

[Explanation of symbols] 1 Faraday element 2 Polarizer 3 Analyzer 4 adhesive 5 Cylindrical magnet

   ─────────────────────────────────────────────────── ─── Continued front page    (31) Priority claim number Japanese Patent Application No. 2002-22704 (P2002-22704) (32) Priority date January 31, 2002 (January 31, 2002) (33) Priority claiming country Japan (JP) (72) Inventor Wakao             Gunma Prefecture Usui District, Matsuida Town             Shin-Etsu Chemical Co., Ltd. Silicone electronic materials             Inside the technical laboratory (72) Inventor Toshio Shiobara             Gunma Prefecture Usui District, Matsuida Town             Shin-Etsu Chemical Co., Ltd. Silicone electronic materials             Inside the technical laboratory F term (reference) 4J036 AA01 AD08 CD16 FB08 JA06                       JA15                 4J040 EC001 EC462 EK032 KA03                       KA16 KA42 NA17

Claims (9)

[Claims] 1. An adhesive for adhering an optical element to a substrate, which comprises (A) a liquid epoxy resin and (B) a particle size of 4.
The composition contains an inorganic filler having a content of particles of 5 μm or more of 1% by weight or less and an average particle size of more than 1 μm and 20 μm or less, and the content of the inorganic filler is 20 to 9 of the entire composition.
An adhesive for optical devices, which comprises a liquid epoxy resin composition of 0% by weight. 2. The adhesive for optical devices according to claim 1, wherein the liquid epoxy resin composition contains (C) a silicone-modified resin. 3. The silicone-modified resin (C) comprises an alkenyl group of an alkenyl group-containing epoxy resin and / or an alkenyl group-containing phenol resin and the following average formula (1) H _a R _b SiO 2 _{(4-ab) / 2} (1 _). (In the formula, R is a substituted or unsubstituted monovalent hydrocarbon group, a is 0.005 to 0.1, b is 1.8 to 2.2, and a +
The range of b is 1.81 ≦ a + b ≦ 2.3. The copolymer obtained by the addition reaction with the SiH group of the organopolysiloxane having 20 to 400 silicon atoms and 1 to 5 SiH groups in one molecule represented by the formula (1). Adhesive for optical devices. 4. The silicone-modified resin (C) has the following general formula (2) and general formula (3): (In the formula, R ¹ is a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group, an alkoxy group or an alkoxyalkyl group, R ² is a substituted or unsubstituted monovalent hydrocarbon group, and R ³ is a hydrogen atom or a glycidyl group. , R ⁴ represents a hydrogen atom, a methyl group or a trifluoromethyl group, R ⁵ represents a substituted or unsubstituted divalent hydrocarbon group, and n, p and q are integers of 0 or more.) The adhesive for optical devices according to claim 2, which is selected from an epoxy resin and a silicone-modified phenol resin. 5. The optical device according to claim 2, wherein a silicone-modified epoxy resin (C-1) and a silicone-modified phenol curing agent (C-2) are used together as the silicone-modified resin (C). Adhesive. 6. A silicone-modified epoxy resin (C-1)
Is represented by the following general formula (4): (In the formula, R ¹¹ is a glycidyl group, R ¹² is a hydrogen atom, or an unsubstituted or substituted monovalent hydrocarbon group, R ¹³ is a divalent hydrocarbon group, and r is an integer of 0 or more.), And silicone. The modified phenol curing agent (C-2) has the following general formula (5): (In formula, s is an integer greater than or equal to 0.) It is what is shown, The adhesive agent for optical devices of Claim 5 characterized by the above-mentioned. 7. The liquid epoxy resin is a bisphenol type epoxy resin, and includes (A), (C-1) and (C-
The adhesive for optical devices according to claim 5 or 6, wherein the adhesive is contained in a proportion of 5 to 50% by weight with respect to the total amount of the component 2). 8. The liquid epoxy resin composition according to claim 2, wherein the silicone-modified resin is contained in an organic resin component in a proportion of 1 to 30% by weight. Adhesive for optical devices. 9. An optical element according to any one of claims 1 to 8.
An optical device obtained by adhering to a substrate using the adhesive according to the item.