TWI457360B - The epoxy resin composition - Google Patents

Description

Epoxy resin composition

The present invention relates to an epoxy resin composition which has excellent moisture resistance, heat resistance, crack resistance and transparency, and can be used for a coating resin, a coating agent, a printing ink, a photoresist ink, an adhesive, The field of semiconductor sealing materials, molding materials, casting materials, and electrical insulating materials is particularly suitable for sealing of light-emitting diodes (hereinafter referred to as LEDs).

Since epoxy resin has excellent electrical properties, adhesion, heat resistance, etc., it is mainly used in various fields of coatings, civil engineering, and electrical fields. In particular, aromatic epoxy resins such as bisphenol A type diglycidyl ether, bisphenol F type diglycidyl ether, phenol novolac type epoxy resin, and cresol novolac type have excellent water resistance. It is widely used in combination with various curing agents in terms of properties, mechanical properties, heat resistance, electrical insulation properties, economy, and the like. However, these aromatic epoxy resins are easily deteriorated by ultraviolet rays or the like, and thus there is a limitation in use in the field where light resistance is required. In recent years, optical semiconductors represented by LEDs have been used in various applications such as display applications, portable computers, mobile phones, and the like, backlights, sensors, and vehicle parts, and are expected to be developed for lighting applications in the future. Most of these optical semiconductors use an epoxy resin as a sealing resin. Among them, a solid epoxy resin of BPA type epoxy resin or alicyclic skeleton which is solid at normal temperature is used for molding by a transfer mold. However, the heat resistance condition of the sealing resin required for the high luminance (=high temperature) of the LED becomes more and more strict.

Patent Document 1 discloses an epoxy resin composition for electric and electronic materials, which comprises a hydrogenated epoxy resin obtained by hydrogenating an aromatic epoxy resin. Patent Document 2 discloses an epoxy resin composition for optical semiconductor sealing which uses a specific hardening accelerator for an aromatic or alicyclic epoxy resin. Patent Document 3 discloses an epoxy resin composition containing no halogen in a curing accelerator and other additives, and the alicyclic epoxy resin is blended in a specific ratio. Patent Document 4 proposes an epoxy resin composition for LED sealing, which comprises: a hydrogenated epoxy resin obtained by hydrogenating an aromatic epoxy resin (or a hydrogenated epoxy resin obtained by hydrogenating an aromatic epoxy resin and a polycarboxylic acid) An epoxy resin obtained by an acid reaction, an alicyclic epoxy resin obtained by epoxidizing a cyclic olefin, and an acid anhydride hardener or a cationic polymerization initiator. However, in order to improve the long-term environmental reliability, it is desirable to have crack resistance when applying thermal cycles, and in order to satisfy the performance of such requirements, it is expected to simultaneously satisfy the high Tg (glass transition temperature) in the trade-off relationship. Low elastic modulus in the rubber field, but the solid transparent epoxy resin of the prior art does not adequately meet the performance requirements.

Patent Document 1: Japanese Patent No. 3537119

Patent Document 2: Japanese Patent Laid-Open No. Hei 5-9268

Patent Document 3: Japanese Laid-Open Patent Publication No. Hei 9-213997

Patent Document 4: Japanese Laid-Open Patent Publication No. 2003-277473

The present invention has been made in view of the above circumstances, and an object thereof is to provide an epoxy resin composition which is suitable for use in the fields of paints, inks, photoresist inks, adhesives, and electronic materials, particularly in the field of LED sealing. It has a solid state and low water absorption, and has excellent crack resistance, heat resistance and transparency.

The present inventors have made efforts to solve the above problems of the epoxy resin, and finally completed the present invention. That is, it has been found that the above problems can be solved by using the epoxy resin composition described below and a cured product obtained by hardening the epoxy resin composition. The epoxy resin composition comprising a bifunctional epoxy resin (a) having an epoxy equivalent of 120 to 350 g/eq and a polyester compound (b) having 1.2 to 1.8 carboxyl groups per molecule. The epoxy resin (A) having an aromatic ring content of 5 to 40% and the cured product (B) are essential components.

The solid epoxy resin (A) used as an essential component in the epoxy resin composition of the present invention is a bifunctional epoxy resin (a) having an epoxy equivalent of 120 to 350 g/eq and having 1.2 to 1.8 per molecule. The carboxyl group-containing polyester compound (b) is reacted, that is, the epoxy group of the epoxy resin (a) is reacted with the carboxyl group of the polyester compound (b). The obtained solid epoxy resin (A) has an aromatic ring content of 5 to 40%.

The polyester compound (b) can be obtained by reacting a divalent carboxylic acid or an acid anhydride thereof with a divalent alcohol, and the production method thereof is not particularly limited. A polyester compound having 1.2 to 1.8 carboxyl groups per molecule can be synthesized by reacting a divalent carboxylic acid or an anhydride thereof with respect to the divalent alcohol 1 molar at 1.2 to 1.8 moles. If the number of carboxyl groups per molecule is less than 1.2, the heat resistance of the cured product may be poor; if the number of carboxyl groups per molecule is more than 1.8, the crack resistance of the cured product may be poor.

Examples of the divalent carboxylic acid or an anhydride thereof of one of the components of the polyester compound (b) include methylhexahydrophthalic acid, hexahydrophthalic acid, methyltetrahydrophthalic acid, and tetrahydrophthalic acid. An alicyclic group such as methyl nadic acid, phthalic acid, isophthalic acid or terephthalic acid, and an aromatic polycarboxylic acid and an acid anhydride thereof may be used singly or as a mixture of two or more kinds thereof. .

The divalent alcohol of the other component of the polyester compound (b) may, for example, be an aliphatic diol such as ethylene glycol, propylene glycol, neopentyl glycol or 1,6-hexanediol, or 2,2-bis ( 4-hydroxycyclohexyl)propane, 1,4 cyclohexanedimethanol, bis(4-hydroxycyclohexyl)methane, spiroglycerol, 2-(5-ethyl-5-hydroxymethyl-1,3-dioxin An alicyclic diol such as alk-2-yl)-2-methylpropan-1-ol.

The epoxy equivalent of the bifunctional epoxy resin (a) is from 120 to 350 g/eq. If the epoxy equivalent is less than 120 g/eq, the synthesis may be difficult; if it exceeds 350 g/eq, the heat resistance of the cured product may be poor. Specific examples of the bifunctional epoxy resin (a) include 2,5-di-tert-butyl-1,4-phenylenebis diglycidyl ether and 2,5-dimethyl- 1,4-phenylphenyl diglycidyl ether, 2,2-bis(4-hydroxyphenyl)propane diglycidyl ether, bisphenol C diglycidyl ether, bisphenol Z diglycidyl ether, bisphenol hydrazine The diglycidyl ether, the biscresol bisglycidyl ether, and the like, may be used singly or as a mixture of two or more kinds.

The epoxy resin (a) and the polyester compound (b) used in the solid epoxy resin (A) must have an aromatic ring in at least one of them, and the aromatic ring content in the solid epoxy resin (A) must be adjusted to 5 to 40%. When the aromatic ring content exceeds 40%, the heat discoloration property is deteriorated. In addition, when the temperature is less than 5%, the heat resistance is also deteriorated. The aromatic ring content is preferably from 10 to 30%, more preferably from 13 to 25%. The aromatic ring content is calculated as the weight % of the aromatic ring in the solid epoxy resin (A).

The production method of the solid epoxy resin (A) is not particularly limited, and a conventionally known method can be applied. In a representative method, the epoxy compound (b) equivalent to 1 equivalent of the epoxy group of the epoxy resin (a) may be used in a ratio of 0.2 to 0.9 equivalents (preferably 0.3 to 0.6 equivalents) in the carboxyl group. It is prepared by reacting at 120 to 180 ° C in the presence of a catalyst. When the proportion of the carboxyl group is less than 0.2 equivalent, the softening point is low and the adhesion resistance is also deteriorated; when the ratio of the carboxyl group is more than 0.9 equivalent, the melt viscosity is increased, so that the usability at the time of hardening is deteriorated.

The solid epoxy resin (A) thus obtained has an epoxy equivalent of 300 to 1000 g/eq, a softening temperature of 60 to 120 ° C, and preferably an epoxy equivalent of 400 to 900 g/eq. When the epoxy equivalent is less than 300 g/eq, the crosslinking density of the cured product becomes high and the crack resistance is insufficient. When the epoxy equivalent is more than 1000 g/eq, the heat resistance is deteriorated.

The composition of the present invention contains a solid epoxy resin (A) as an essential component, but may be blended with a hardener used in a usual epoxy resin hardener. Further, a cationic polymerization initiator, an antioxidant, an ultraviolet absorber, or the like may be blended.

As the hardener (B), various known compounds can be used. For example, an organic amine compound, dicyandiamide and a derivative thereof, 2-methylimidazole, 2-ethyl-4-methylimidazole, and the like, and bisphenol A, bisphenol F, and bromine can be used. a bisphenol compound such as bisphenol A, naphthalenediol or 4,4'-bisphenol; a phenol resin or an aralkyl phenol resin obtained by condensation reaction of phenol or naphthol with formaldehyde or benzenedimethanol; succinic anhydride, Anhydride anhydride compounds such as maleic anhydride, phthalic anhydride, hexahydrophthalic anhydride, methyl hexahydrophthalic anhydride, nadic anhydride, hydrogenated adduct anhydride, trimellitic anhydride, and pyromellitic anhydride; As the ruthenium compound such as bismuth diacid, two or more kinds may be used as the case may be. Among these, an acid anhydride compound is preferable, and a hydrogenated acid anhydride is more preferable, and methyl hexahydrophthalic anhydride is particularly preferable. By using these acid anhydride compounds, it is possible to obtain less hardening shrinkage, transparency, and excellent weather resistance. An epoxy resin composition having less yellowing at high temperatures.

As the hardening accelerator, various known compounds can be used. For example, a tertiary amine and a salt thereof, an imidazole and a salt thereof, an organic phosphine compound (which means an organic phosphine and a salt thereof), an organic metal salt such as zinc octylate or tin octylate may be mentioned, as the case may be. Two or more types can be used. The hardener is preferably a tertiary amine and a salt thereof, an organic phosphine compound, and the organic phosphine compound is particularly preferred because it prevents coloration of the hardened material.

Other additives include antioxidants, ultraviolet absorbers, various other fillers, film formers, dyes, mold release agents, flow regulators, flame retardants, rubber modifiers, surfactants, reactive diluents, Various types of oligomers, various polymers, and the like may be used depending on the case. In particular, the epoxy resin composition for an optical semiconductor of the present invention preferably contains an antioxidant, and is a cured product which can prevent oxidative degradation during heating and which is less colored.

For antioxidants, various compounds can be used. For example, 2,6-di-t-butyl-p-cresol, 2,6-di-t-butyl-4-ethylphenol, butylated hydroxy-methyl ether, stearin-β-( Monophenols such as 3,5-di-t-butyl-4-hydroxyphenyl)propionate; 2,2-extended methyl bis(4-methyl-6-tert-butylphenol), 2, Bis-methyl bis(4-ethyl-6-tributylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), etc.; 1,1 , 3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di- Polymeric phenol such as tributyl-4-hydroxybenzyl)benzene, tetrakis-methyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate methane , 9,10-dihydro-9-sideoxy-10-phosphorylated phenanthrene-10-oxide, 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10 -Dihydro-9-sideoxy-10-phosphorylated phenanthrene-10-oxide, 10-decyloxy-9,10-dihydro-9-sideoxy-10-phosphorylated phenanthrene-10-oxide Oxyphosphorus phenanthrene oxides, etc. These oxidation inhibitors may be used in two or more types as the case may be.

Example

Next, the present invention will be more specifically described with reference to the synthesis examples, examples, and comparative examples of the present invention.

Synthesis Example 1

In a reaction apparatus equipped with a stirrer, a thermometer, a nitrogen gas blowing tube, and a cooling tube, 215 parts of RIKACID MH (methyl hexahydrophthalic anhydride; manufactured by Nippon Chemical and Chemical Co., Ltd.) and 192 parts of RIKABINOL HB (hydrogenated BPA; new A mixture of Nippon Physicochemical Co., Ltd. was reacted at 150 ° C for 2 hours while stirring under a nitrogen atmosphere to obtain a terminal carboxyl group polyester having a carboxyl group number of 1.6 per molecule and a carboxyl equivalent of 320 g/eq at a normal temperature. Compound. Next, 507 parts of YDC-1312 (2,5-di-t-butyl-1,4-phenylphenyl diglycidyl ether; manufactured by Dongdu Chemical Co., Ltd., epoxy equivalent: 178 g/eq, melting point 142 ° C) and 0.2 part by weight of triphenyl phosphate was stirred and mixed at 150 ° C for 4 hours to obtain a solid epoxy resin c-1 having a softening point of 94 ° C, an epoxy equivalent of 580 g / eq, and an aromatic ring content of 13.8%.

Synthesis Example 2

In Synthesis Example 1, 243 parts of spiroglycerol (manufactured by Japan FineChem Co., Ltd.) was used instead of RIKABINOL HB, and a terminal carboxyl group polyester compound having a carboxyl group number of 1.6 per molecule and a carboxyl group equivalent of 320 g/eq at a normal temperature was obtained. Then, 450 parts of YD-128 (2,2-bis(4-hydroxyphenyl)propane diglycidyl ether; manufactured by Tohto Kasei Co., Ltd., epoxy equivalent: 187 g/eq, viscosity: 13,000 mPs‧s/25 ° C) and 0.1 weight were charged. The triphenyl phosphate was stirred and mixed at 150 ° C for 4 hours to obtain a solid epoxy resin c-2 having a softening point of 92 ° C, an epoxy equivalent of 820 g/eq, and an aromatic ring content of 23.1%.

Examples 1 to 2 and Comparative Examples 1 to 2

Epoxy resin c-1 obtained in Synthesis Example 1 and epoxy resin c-2 and YD-012 obtained in Synthesis Example 2 (bisphenol A type solid epoxy resin, epoxy equivalent: 645 g/eq, softening point: 81 ° C, Aromatic ring content: 51.2%; manufactured by Tohto Kasei Co., Ltd.), EHPE 3150 (aliphatic skeleton solid epoxy resin, epoxy equivalent 180 g/eq, softening point 78 ° C, aromatic ring content: 0%; manufactured by Daicel Chemical Co., Ltd.) as a solid ring As an oxygen resin component, RIKACID MH-700 (methyl hexahydrophthalic anhydride, anhydride equivalent: 168 g/eq; manufactured by Nippon Chemical Co., Ltd.) was used as a curing agent, and HISHICOLIN PX-4ET (organic sulfonium salt compound; manufactured by Nippon Chemical Co., Ltd.) was used. As the hardening accelerator, an epoxy resin composition was obtained from the mixing ratio shown in Table 1. Here, the numerical values in the tables indicate the parts by weight.

The epoxy resin composition was molded at 100 ° C for 2 hours, and then post-cured at 140 ° C for 12 hours to obtain a cured test piece, which was then provided as a measurement of various physical properties. The results are shown in Table 2.

Among them, the test method and evaluation method of hardened physical properties are as follows:

(1) Glass transition temperature and dynamic viscoelastic modulus: determined by DMA.

(2) Water absorption rate: A circular test piece having a diameter of 50 mm and a thickness of 5 mm was used as a water absorption rate after water absorption at a temperature of 23 ° C and 100% RH for 50 hours.

(3) Heat-resistant discoloration property: A test piece having a diameter of 10 mm and a thickness of 5 mm was prepared, and it was confirmed whether or not there was discoloration.

(4) Cracking rate: A test piece of a sealed LED element having a diameter of 10 mm and a thickness of 5 mm was prepared, and a thermal cycle test was performed at -20 ° C (30 minutes) to 120 ° C (15 minutes) to 20 ° C (30 minutes). Five times, the number of cracks in 10 test pieces was recorded.

As is apparent from the above examples, the epoxy resin composition of the epoxy resin (A) of the present invention can provide a cured product having excellent high Tg, low water absorption, and low modulus of elasticity in the rubber field. Therefore, it is suitable for use in an electronic material field such as an optical semiconductor sealing material because of its heat resistance, moisture resistance, and crack resistance, and is particularly suitable as an epoxy resin composition for LED sealing.

Industrial availability

The epoxy resin composition of the present invention has excellent heat resistance, moisture resistance and crack resistance, and thus can be suitably used in the field of electronic materials such as optical semiconductor sealing materials, and is particularly suitable as an epoxy resin for LED sealing. Things.

Claims (4)

An epoxy resin composition comprising an aromatic ring obtained by reacting a bifunctional epoxy resin (a) having an epoxy equivalent of 120 to 350 g/eq with a polyester compound (b) having 1.2 to 1.8 carboxyl groups per molecule A solid epoxy resin (A) having a content of 5 to 40% and an epoxy equivalent of 300 to 1000 g/eq, and a cured product (B) are essential components. The epoxy resin composition of claim 1, wherein the bifunctional epoxy resin (a) having an epoxy equivalent of 120 to 350 g/eq is at least one of the following: 2,5-di- Tributyl-1,4-phenylene diglycidyl ether or 2,2-bis(4-hydroxyphenyl)propane diglycidyl ether. The epoxy resin composition of claim 1 or 2, wherein the solid epoxy resin (A) has a softening point of 60 to 120 °C. A cured product obtained by curing an epoxy resin composition according to any one of claims 1 to 3.