JP2009167240A - Epoxy resin, epoxy resin composition and cured product thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin exhibiting high heat resistance and excellent mechanical strengths. <P>SOLUTION: The epoxy resin is a bisphenol A novolak-type epoxy resin having a softening point of 60-100°C, where the ratio of the monosubstituted phenol residue (A) to the disubstituted phenol residue (B), (A)/(B), is at least 15. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an epoxy resin excellent in heat resistance and mechanical strength.

  As the epoxy resin, diglycidyl ether (liquid form) of bisphenol A is generally widely known, and polyglycidyl etherified products of phenol novolac and cresol novolac are mainly used in fields where high heat resistance is required. .

WO2004 / 020492

  Further, in the application of electronic parts such as semiconductor encapsulants and substrates, when soldering is performed due to the recent increase in environmental protection awareness, the conventional lead-containing solder is rapidly shifting to lead-free solder. Since lead-free solder has a melting temperature about 20 ° C higher than that of conventional solder, if the heat resistance and mechanical strength of the resin used in electronic components are inferior, a small amount of water contained in the resin is exposed to the solder bath. In such a case, a phenomenon in which the components rapidly evaporate and damages the inside or appearance of the component is likely to occur. In order to solve such problems, an epoxy resin excellent in heat resistance and mechanical strength has been awaited.

  In light of these circumstances, the present inventors have intensively studied for an epoxy resin excellent in heat resistance and mechanical strength, and as a result, completed the present invention.

That is, the present invention relates to (1) a bisphenol A novolac type epoxy resin having a softening point of 60 to 100 ° C.

で表されるフェノール残基（Ａ）と、下記式（３）

And a phenol residue (A) represented by the following formula (3)

で表されるフェノール残基（Ｂ）の比率（Ａ）／（Ｂ）が１５以上であるエポキシ樹脂、
（２）上記（１）記載のエポキシ樹脂、硬化剤を含むエポキシ樹脂組成物、
（３）硬化促進剤を含有する上記（２）記載のエポキシ樹脂組成物、
（４）無機充填剤を含有する上記（２）乃至（３）記載のエポキシ樹脂組成物、
（５）上記（２）乃至（４）のいずれか１項に記載のエポキシ樹脂組成物の硬化物、
を提供するものである。

An epoxy resin in which the ratio (A) / (B) of the phenol residue (B) represented by
(2) the epoxy resin according to (1) above, an epoxy resin composition containing a curing agent,
(3) The epoxy resin composition according to the above (2), which contains a curing accelerator,
(4) The epoxy resin composition according to the above (2) to (3), which contains an inorganic filler,
(5) A cured product of the epoxy resin composition according to any one of (2) to (4) above,
Is to provide.

  A cured product using the epoxy resin of the present invention has high heat resistance and excellent mechanical strength, and is therefore suitable for electronic parts using lead-free solder.

  The epoxy resin of the present invention can be obtained by glycidyl etherification of a specific bisphenol A novolac resin. The bisphenol A novolak resin used as the raw material can be obtained by subjecting bisphenol A and formalin to a condensation reaction in the presence of an acid catalyst. The softening point of a bisphenol A novolak resin suitable as a raw material for the epoxy resin of the present invention is usually 90 to 150 ° C, preferably 100 to 140 ° C. The softening point of the bisphenol A novolac resin is determined almost uniquely by the charge ratio of bisphenol A and formalin used in the reaction. The molar ratio of bisphenol A and formalin used to obtain the softening point bisphenol A novolak resin is usually 0.50 to 0.95 mol, preferably 0.55 to 0.90, with respect to 1 mol of bisphenol A. Is a mole.

  Examples of the acid catalyst include oxalic acid, p-toluenesulfonic acid, and phosphoric acid. The method of the condensation reaction is not particularly limited, but the following formula

で表される、フェノール残基（Ａ’）と下記式

A phenol residue (A ′) represented by the following formula:

で表されるフェノール残基（Ｂ’）の比率（Ａ’）／（Ｂ’）が１５以上になる方法を選択する必要がある。その例の１つとして特許文献１で例示されているような不均一系反応を採用することが出来る。

It is necessary to select a method in which the ratio (A ′) / (B ′) of the phenol residue (B ′) represented by As one example, a heterogeneous reaction exemplified in Patent Document 1 can be employed.

In the epoxidation of the phenol resin, the phenol resin and epihalohydrin are usually reacted.
In the present invention, epichlorohydrin or epibromohydrin can be used as the epihalohydrin. The amount of epihalohydrin is usually 2 to 15 mol, preferably 3 to 12 mol, per 1 equivalent of hydroxyl group in the bisphenol A novolak resin.

  Examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, and the like. Solid or an aqueous solution thereof may be used. When an aqueous solution is used, it is continuously added to the reaction system and simultaneously under reduced pressure. Alternatively, normal pressure sewage and epihalohydrin may be allowed to flow out and separated, water may be removed, and epihalohydrin may be continuously returned to the reaction system. The usage-amount of an alkali metal hydroxide is 1.0-1.2 mol normally with respect to 1 equivalent of a hydroxyl group, Preferably it is 1.05-1.15 mol. The reaction temperature is usually 20 to 110 ° C, preferably 25 to 100 ° C. The reaction time is usually 0.5 to 15 hours, preferably 1 to 10 hours.

  In order to accelerate the reaction, alcohols such as methanol, ethanol, isopropyl alcohol and tertiary butanol, or aprotic polar solvents such as dimethyl sulfoxide and dimethyl sulfone may be added. When alcohols are used, the amount used is usually ~ wt%, preferably ~ wt%, based on the amount of epihalohydrin. When an aprotic polar solvent is used, the amount used is usually 10 to 150% by weight, preferably 15 to 120% by weight, based on the amount of epihalohydrin.

  In addition, a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide, tetraethylammonium bromide, trimethylbenzylammonium chloride or the like is added as a catalyst to a solution of epihalohydrin and bisphenol A novolak resin to obtain a solid or aqueous solution of an alkali metal hydroxide. In addition, a method of reacting at 20 to 100 ° C. for 1 to 10 hours may be used.

  The reaction product of these epoxidation reactions is washed with water, and then removed with an excess of epihalohydrin and a solvent under heating and reduced pressure. Furthermore, in order to make an epoxy resin with less hydrolyzable halogen, the recovered epoxy resin is dissolved in toluene, methyl isobutyl ketone, etc., and an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added to perform ring closure. Can also be ensured. In this case, the usage-amount of an alkali metal hydroxide is 0.01-0.3 mol normally with respect to the total of 1 equivalent of the hydroxyl group in bisphenol A novolak resin, Preferably it is 0.05-0.2 mol. The reaction temperature is usually 50 to 120 ° C., and the reaction time is usually 0.5 to 2 hours.

After completion of the reaction, the produced salt is removed by filtration, washing with water, etc., and the solvent is removed under reduced pressure by heating to obtain the epoxy resin of the present invention. The bisphenol A novolak epoxy resin thus obtained should have a ratio (A) / (B) of the above-mentioned phenol residue (A) to phenolic residue (B) of usually 15 or more, preferably 17 or more. It is. The ratio of each residue can be calculated by comparing the integrated value of the carbon atom of the vacant phenyl nucleus with the integrated value of the carbon atom at the α-position of the glycidyl group in ¹³ C-NMR.

  The epoxy resin of the present invention can be used as a curable resin composition by combining with a curing agent, a curing catalyst, a cyanate resin and the like. Specific examples of applications include printed wiring boards, semiconductor sealing materials, solder resists, and the like.

  Hereinafter, the epoxy resin composition of the present invention will be specifically described.

  In the epoxy resin composition of the present invention, the epoxy resin of the present invention can be used alone or in combination with other epoxy resins. When used together, the proportion of the epoxy resin of the present invention in the total epoxy resin is preferably 30% by weight or more, particularly preferably 40% or more.

  In addition to the epoxy resin of the present invention, an epoxy resin having one or more epoxy groups in one molecule can be partially used. Specific examples of the epoxy resin used at this time include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, triphenylmethane type epoxy resin, biphenyl novolac type epoxy resin, biphenol type epoxy resin, and fat. Examples thereof include cyclic epoxy resins. These epoxy resins may be used alone or in combination of two or more thereof to the epoxy resin of the present invention.

Examples of the curing agent contained in the epoxy resin composition of the present invention include amine compounds, acid anhydride compounds, amide compounds, phenol compounds, and the like. Specific examples of curing agents that can be used include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, dicyandiamide, polyamide resin synthesized from linolenic acid and ethylenediamine, phthalic anhydride, triethylene anhydride. Merit acid, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phenol novolac, and modified products thereof, Examples include, but are not limited to, imidazole, BF ₃ -amine complexes, guanidine derivatives, and the like. These may be used alone or in combination of two or more.

  In the epoxy resin composition of the present invention, the amount of the curing agent used is preferably 0.7 to 1.2 equivalents relative to 1 equivalent of the epoxy group of the epoxy resin. When less than 0.7 equivalent with respect to 1 equivalent of epoxy groups, or when exceeding 1.2 equivalent, in any case, curing may be incomplete, and good cured properties may not be obtained.

  In the epoxy resin composition of the present invention, the amount of the curing agent used is preferably 0.7 to 1.2 equivalents relative to 1 equivalent of the epoxy group of the epoxy resin. When less than 0.7 equivalent with respect to 1 equivalent of epoxy groups, or when exceeding 1.2 equivalent, in any case, curing may be incomplete, and good cured properties may not be obtained.

The epoxy resin composition of the present invention contains a curing accelerator as necessary.
The curing accelerator used in the present invention only needs to function as a curing accelerator for ordinary epoxy resins, and in the epoxy resin composition of the present invention, two or more kinds of accelerators are used in combination. There is no problem. Specifically, 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2 -Methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 2,4-diamino-6 (2'-methylimidazole (1 ')) Ethyl-s-triazine, 2,4-diamino-6 (2′-undecylimidazole (1 ′)) ethyl-s-triazine, 2,4-diamino-6 (2′-ethyl, 4-methylimidazole (1 ')) Ethyl-s-triazine, 2,4-diamino-6 (2'-methylimidazole (1') ) Ethyl-s-triazine-isocyanuric acid adduct, 2-methylimidazole isocyanuric acid 2: 3 adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-3,5-dihydroxymethylimidazole, 2-phenyl- Various imidazoles of 4-hydroxymethyl-5-methylimidazole, 1-cyanoethyl-2-phenyl-3,5-dicyanoethoxymethylimidazole, and imidazoles and phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, Salts with polyvalent carboxylic acids such as pyromellitic acid, naphthalenedicarboxylic acid, maleic acid and succinic acid, amides such as dicyandiamide, diaza compounds such as 1,8-diaza-bicyclo (5.4.0) undecene-7, And phenols of the above compounds, polycarboxylic acids , Salts with tetraphenylborate, or salts with phosphinic acids, ammonium salts such as tetrabutylammonium bromide, cetyltrimethylammonium bromide, trioctylmethylammonium bromide, other phosphines such as triphenylphosphine, tetraphenylphosphonium tetraphenylborate And phenols such as 2,4,6-trisaminomethylphenol, amine adducts, and microcapsule type curing accelerators in which these curing agents are made into microcapsules.

  The usage-amount of a hardening accelerator is 0.05-5 weight part normally with respect to 100 weight part of the whole epoxy resin containing the epoxy resin of this invention, Preferably it is 0.07-3 weight part.

  The epoxy resin composition of the present invention contains the above-described specific epoxy resin, curing agent, and curing accelerator as essential components, but flame retardant, colorant, coupling agent, stress-reducing agent, if necessary, A filler etc. can be mix | blended.

  The epoxy resin composition of the present invention is obtained by uniformly mixing each component, and a cured product can be easily obtained by a method similar to a conventionally known method. For example, a mixture of components of the epoxy resin composition of the present invention (including fillers and other additives as necessary) is uniformly mixed using a kneader, an extruder, a roll, etc., and then melted and cast or transferred. A cured product can be obtained by molding using a molding machine or the like and further heating at 80 to 120 ° C. for 1 to 12 hours.

  In addition, the epoxy resin composition of the present invention is dissolved in a solvent such as methyl ethyl ketone, acetone, methyl isobutyl ketone, toluene, dimethylformamide and the like, and is based on glass fiber, glass nonwoven fabric, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, paper or the like. A cured product can also be obtained by hot press molding a prepreg obtained by impregnating a material and then drying by heating.

  As a general method for preparing a prepreg, the resin composition of the present invention and a solvent are blended at a predetermined ratio to obtain a varnish. Next, glass cloth or the like is impregnated with varnish and dried to obtain a prepreg having a resin amount of 40 to 60%. In order to obtain a laminate, a predetermined number of prepregs can be laminated and heated and cured at 90 to 160 ° C. for 30 to 120 minutes in a press.

  EXAMPLES Next, the present invention will be described more specifically with reference to examples. In the following, parts are parts by weight unless otherwise specified.

Synthesis Example 1
Bisphenol A, 92% paraformaldehyde, phosphoric acid, and methanol were reacted in a pressure-resistant reaction vessel equipped with a thermometer and a stirrer according to Patent Document WO 2004/020492 to obtain a bisphenol A novolac resin having a softening point of 133 ° C.

  After adding 117 parts of the bisphenol A novolak resin obtained above, 370 parts of epichlorohydrin and 26 parts of methanol, adding 40 parts of flaky sodium hydroxide over 100 minutes at 70 ° C., and further reacting for 1 hour, The temperature was raised to 70 degrees and reacted for 1 hour. Thereafter, washing with water was performed once to remove generated salts and the like, and excess unreacted epichlorohydrin was distilled off under heating and reduced pressure, and then 346 parts of methyl isobutyl ketone was added to the residue and dissolved. After raising the temperature to 70 ° C., 10 parts of 30% aqueous sodium hydroxide solution was added and reacted for 1 hour, followed by washing with water three times. (A) 164 parts were obtained. The epoxy equivalent of the obtained epoxy resin was 198 g / eq, the softening point was 82.5 ° C., and the ratio (A) / (B) of the phenol residue calculated from the integral value of NMR was 19.7. .

Synthesis Example 2
Add bisphenol A, 92% paraformaldehyde, paratoluenesulfonic acid, isopropanol to the reactor equipped with a thermometer, stirrer, and condenser and let it react at 120 ° C for an hour, then add methyl isobutyl ketone at the end of the reaction and wash with water. The reaction catalyst and the like were removed. Subsequently, the solvent was distilled off under reduced pressure by heating to obtain a bisphenol A novolak resin having a softening point of 133 ° C.

  Epoxidation was performed in the same manner as in Synthesis Example 1 to obtain an epoxy resin (b) having an epoxy equivalent of 201 g / eq and a softening point of 83.1 ° C. The ratio (A) / (B) of the phenol residue calculated from the integrated value of NMR was 13.2.

Example 1 and Comparative Example 1
For resins (a) and (b) obtained in Synthesis Examples 1 and 2, phenol novolak (hydroxyl equivalent: 106 g / eq, softening point: 82 ° C.) as a curing agent and triphenylphosphine as a curing accelerator as an epoxy resin. 1 part per 100 parts was mixed uniformly using a biaxial roll, and a resin molded body was prepared by a transfer molding machine (150 to 160 ° C., 150 to 200 seconds, 50 Kg / cm ² ). Further, it was cured at 180 ° C. for 8 hours.

The test piece thus prepared was measured by the following items and methods. The test results are shown in Table 1.
Glass transition temperature: TMA method Deflection amount: Performed according to JIS C-6481 (bending strength). However, the measured value indicates the amount of deflection at the time of test deformation.

Table 1
Examples Comparative Example Epoxy Resin (a) (b)
Glass transition temperature (° C) 162 158
Deflection (mm) 2.5 2.2

Claims (5)

In the bisphenol A novolac type epoxy resin having a softening point of 60 to 100 ° C., the following formula

A phenol residue (A) represented by the following formula:

The epoxy resin whose ratio (A) / (B) of the phenol residue (B) represented by is 15 or more. An epoxy resin composition comprising the epoxy resin according to claim 1 and a curing agent. The epoxy resin composition of Claim 2 containing a hardening accelerator. The epoxy resin composition according to claim 2, which contains an inorganic filler. Hardened | cured material of the epoxy resin composition of any one of Claims 2 thru | or 4.