JP3084848B2 - Epoxy resin and composition thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin particularly useful for sealing electronic parts and an epoxy resin composition comprising the same and a curing agent.

[0002]

2. Description of the Related Art In recent years, transfer molding of an epoxy resin composition which is economically advantageous for encapsulating semiconductors such as LSIs, ICs and transistors has been performed. In particular, recently, LSIs are surface-mounted, and the number of cases where LSIs are directly immersed in a solder bath is increasing. In that case, the sealing material is 2
Since it is exposed to a high temperature of 00 ° C. or more, moisture contained in the sealing material expands due to moisture absorption, and cracks are easily generated. For this reason, epoxy resin sealing materials are required to have low moisture absorption and crack resistance, and at present, glycidyl ether of o-cresol novolak is mainly used.

[0003]

The sealing material mainly composed of glycidyl ether of o-cresol novolac has excellent heat resistance and a good balance between heat resistance and low hygroscopicity. In applications where a higher level of low hygroscopicity is required, it is not always sufficient and improvement has been desired.

[0004] As a low moisture-absorbing epoxy resin, for example, glycidyl ether of tetramethylbiphenol has been proposed, but is not always sufficient and has a drawback of poor heat resistance. An object of the present invention is to provide an epoxy resin which exhibits lower moisture absorption while suppressing a decrease in heat resistance, and improves crack resistance.

[0005]

SUMMARY OF THE INVENTION The present invention provides a general formula 2

[0006]

Embedded image (Wherein GE is a glycidyl ether group, R ₁ is each independently a hydrogen atom, an alkyl group or a halogen atom having 1 to 6 carbon atoms, R ₂ is a cyclohexyl group or a substituted cyclohexyl group, R ₃ is a hydrogen atom, An alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 14 carbon atoms. The average repeating unit number n is a number of 0 to 10.) And an epoxy resin composition comprising:

In the epoxy resin of the present invention, the substituent R
₁ is each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a halogen atom, and specific examples thereof include a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group,
An amyl group, a hexyl group (including isomers include isomers), a chlorine atom or a bromine atom, and preferably a hydrogen atom, a methyl group, a chlorine atom or a bromine atom.

In the epoxy resin of the present invention, the substituent R
₂ represents a cyclohexyl group or a substituted cyclohexyl group having an alkyl group having 1 to 6 carbon atoms or a halogen atom, and is preferably a cyclohexyl group.

In the epoxy resin of the present invention, the substituent R
₃ is each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 14 carbon atoms, and specific examples thereof include a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, and an amyl group. A hexyl group (each having an isomer includes each isomer), a phenyl group or a naphthyl group, preferably a hydrogen atom, a methyl group, a phenyl group or a naphthyl group.

The average number n of repeating units of the epoxy resin of the present invention is a number of 0 to 10, preferably a number of 0 to 8. If n exceeds 10, the viscosity becomes too high and the moldability deteriorates, which is not preferable. The epoxy resin of the present invention has the general formula 3

[0011]

Embedded image (Wherein, the definitions of R ₁ , R ₂ , R ₃ and n are the same as those in the above-mentioned chemical formula ₂ ).

The polyhydric phenols represented by the above formula (3) can be obtained, for example, by condensing cyclohexylphenols and aldehydes in the presence of an acidic catalyst.

Examples of the cyclohexyl phenols include cyclohexyl phenol, cyclohexyl phenol having an alkyl group having 1 to 6 carbon atoms, chlorocyclohexyl phenol, and bromocyclohexyl phenol (including isomers when they have isomers). These cyclohexylphenols are not only used alone,
A mixture of two or more types may be used.

Examples of the above aldehyde include formaldehyde, acetaldehyde, benzaldehyde,
Naphthaldehyde and the like.

The above-mentioned polyhydric phenols can be reacted with inorganic acids such as hydrogen chloride and sulfuric acid, organic acids such as acetic acid, p-toluenesulfonic acid and thioglycolic acid, and acidic catalysts such as Lewis acids, for example, against aldehydes. More than one mole of cyclohexylphenol is condensed, followed by post-treatment such as washing with water, distilling off unreacted phenols, and, in some cases, recrystallization with a poor solvent. Furthermore, the polyhydric phenols can be chlorinated or brominated for the purpose of imparting flame retardancy.

For the glycidyl etherification of the above polyhydric phenols, the phenols and epihalohydrin are
A conventionally known method of reacting in the presence of an alkali such as caustic soda can be used. In particular, when obtaining high-purity products,
As described in JP-A-60-31517, a reaction in an aprotic solvent is preferred.

Examples of the curing agent used in the present invention include polyhydric phenol curing agents such as phenol novolak, amine curing agents such as dicyandiamide, diaminodiphenylmethane and diaminodiphenylsulfone, pyromellitic anhydride, trimellitic anhydride, and benzophenone. An acid anhydride-based curing agent such as tetracarboxylic acid is exemplified, but a polyhydric phenol-based curing agent is preferable.

Examples of the polyhydric phenol-based curing agent include polycondensates of phenols with aldehydes such as formaldehyde, acetaldehyde, acrolein, glyoxal, benzaldehyde and hydroxybenzaldehyde, and vinyl such as polyvinyl phenol and polyisopropenyl phenol. Polymerized polyhydric phenols and phenols, and

[0019]

Embedded image Diols or dialkoxys such as

[0020]

Embedded image Or a Friedel-Crafts type reaction product of a dihalogen or a phenol with a diene or the like such as dicyclopentadiene or diisopropenylbenzene. The amount of these curing agents used is 0.7-1.
Two equivalents. If the amount is less than 0.7 equivalents or more than 1.2 equivalents with respect to the epoxy group, the curing is incomplete and the moisture absorption does not become low.

If necessary, known additives such as a filler, a curing accelerator, a flame retardant, a release agent and a surface treatment agent can be added to the composition of the present invention. As a filler,
Examples thereof include fused silica, crystalline silica, alumina, aluminum hydroxide, and hydrated alumina. They are,
It is also possible to increase the filling amount by mixing different shapes (spherical or crushed types) or sizes. Examples of curing accelerators include imidazoles, tertiary amines, and phosphorus compounds, and examples of flame retardants include brominated epoxy resins and antimony trioxide. Examples of the release agent include waxes and metal salts of higher fatty acids such as zinc stearate, and examples of the surface treatment agent include a silane coupling agent.

Further, for the purpose of, for example, reducing the stress, various elastomers may be added or reacted in advance.
Specific examples include addition-type or reaction-type elastomers such as polybutadiene, butadiene-acrylonitrile copolymer, and silicone rubber. In order to seal an electronic component such as a semiconductor using the resin composition according to the present invention, it is sufficient to cure and mold by a conventionally known molding method such as transfer molding, compression molding, injection molding and the like.

[0023]

The epoxy resin of the present invention has lower hygroscopicity than o-cresol novolak glycidyl ether, and lower than glycidyl ether of tetramethylbiphenol which is said to be a low hygroscopic resin. It exhibits hygroscopicity and a high glass transition temperature, and is useful as a sealing material for electronic components, particularly as a surface mounting material.

[0024]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited to these examples. In the examples, the epoxy equivalent is defined as the molecular weight of the epoxy resin per epoxy group. The hydrolyzable chlorine is obtained by dissolving an epoxy resin in dioxane, adding an alcohol solution of potassium hydroxide, and performing back titration with an aqueous solution of silver nitrate on chlorine ions which are desorbed when heated at reflux for 30 minutes. It is expressed as a percentage by weight in the compound. Also, the number of repeating units n
Was determined by gel permeation chromatography (JASCO Corporation, TRI-ROTAR SR II).

The evaluation of the cured molded product is as follows. -Glass transition temperature: Thermomechanical analyzer (SHIMADZ)
UDT-30). -Flexural strength and flexural modulus: Instron universal material testing machine (SHIMADZU) according to JIS K-6911
IS-10T).・ Water absorption (hygroscopicity): constant temperature and constant humidity chamber (TABAI PR-
Using 2), the weight change was measured under the conditions of 85 ° C./85% RH. -Spiral flow: 17 according to EMMI-1-66
The test was performed at 5 ° C./70 kg / cm ² .

Example 1 317.4 g of cyclohexylphenol, 30 parts of toluene
0 g and 20.6 g of p-toluenesulfonic acid (monohydrate) were charged into a reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, and a condenser with a separation tube, and dissolved and heated. Internal temperature 90 ° C
, 109.5 g of 37% formalin was continuously dropped over 5 hours. During this period, while maintaining the temperature at 90 ° C., azeotropic toluene and water were cooled and liquefied, and the reaction was performed while returning the organic layer into the reaction system. After the completion of the reaction, the reaction mixture was washed with warm water until the pH became neutral, concentrated under reduced pressure, and subjected to steam distillation to obtain cyclohexylphenol novolak. The number n of repeating units was 3.2. By mass spectrum,
364, 552, 740, 928, 1116, 130
4,1492 fragments were observed. Cyclohexylphenol novolak 9 thus obtained
0.7 g (0.7 mol of phenolic hydroxyl group) was charged into a reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, and a condenser equipped with a separation tube, and epichlorohydrin 453.3 was added.
g, dimethyl sulfoxide in 226.7 g. While maintaining the inside of the reaction system at 41 torr,
57.6 g of an 8.6% aqueous sodium hydroxide solution was continuously added dropwise over 8 hours. During this time, while maintaining the temperature at 48 ° C., azeotropic epichlorohydrin and water were cooled and liquefied, and the reaction was performed while returning the organic layer into the reaction system. After completion of the reaction, unreacted epichlorohydrin was removed by concentration under reduced pressure, glycidyl ether containing by-product salt and dimethyl sulfoxide was dissolved in methyl isobutyl ketone, and the by-product salt and dimethyl sulfoxide were removed by washing with water. The epoxy equivalent and hydrolyzable chlorine of the glycidyl ether thus obtained were 284 g / equivalent and 200 ppm, respectively.

Example 2 Cyclohexylphenol novolak was obtained in the same manner as in Example 1 except that the amount of 37% formalin was changed to 102.2 g. The number n of repeating units was 2.8. Further, glycidyl etherification was performed in the same manner as in Example 1. The epoxy equivalent and hydrolyzable chlorine of the obtained glycidyl etherified product were 283 g / equivalent, 22
It was 0 ppm.

Example 3 Except that the amount of 37% formalin was changed to 87.6 g
Cyclohexylphenol novolak was obtained in the same manner as in Example 1. The number n of repeating units was 2.1. Furthermore, glycidyl etherification was performed in the same manner as in Reference Example 1. The epoxy equivalent and hydrolyzable chlorine of the obtained glycidyl etherified product were 280 g / equivalent, 200 pp
m.

Comparative Example 1 2,6-xylenol was treated in the same manner as in Example 1 of JP-A-1-283241 to obtain 3,3 ', 5,5'-tetramethylbiphenol. Glycidyl etherification was carried out in the same manner as in Example 1 except that 84.7 g of 3,3 ′, 5,5′-tetramethylbiphenol was used instead of cyclohexylphenol novolak. The epoxy equivalent and hydrolyzable chlorine of the obtained glycidyl ether product were 194 g / equivalent and 220 ppm.

Examples 4 to 6 and Comparative Examples 2 to 3 Various glycidyl ether compounds obtained in the above Examples and the like, and phenol novolak (trade name: Tamanol 7) as a curing agent
59 Arakawa Chemical Industries, Ltd.), triphenylphosphine as a curing accelerator, and fused silica (FS
-891 manufactured by Denki Kagaku Kogyo Co., Ltd.), carnauba wax as a release agent, and a coupling agent (SH-6040 manufactured by Toray Dow Corning Silicone Co., Ltd.) in an amount (g) shown in Table 1 and roll. Heat kneading was performed and transfer molding was performed. Further, post-curing was performed in a 180 ° C. oven for 5 hours to obtain a cured molded product. The glass transition temperature, water absorption, flexural strength and flexural modulus of the cured molded product were measured. Table 1 shows the results.

[0031]

[Table 1]

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI H01L 23/31 (72) Inventor Hiroshi Shiomi 6 Kitahara, Tsukuba, Ibaraki Prefecture Within Sumitomo Chemical Co., Ltd. (72) Inventor Shigeki Naito Ibaraki 6 in Kitahara, Tsukuba, Japan Sumitomo Chemical Co., Ltd. (72) Inventor Shuichi Kanakawa, 6 in Sumitomo Chemical Co., Ltd., Kitahara, Tsukuba, Ibaraki Prefecture (56) References JP-A-3-27373 (JP, A) JP JP-A-63-264623 (JP, A) JP-A-48-30799 (JP, A) Table of Japanese Patent Application No. Sho 61-500024 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 59 / 08 C08G 59/24 C08G 59/32 C08G 59/62 C07D 303/30 H01L 23/29

Claims (3)

(57) [Claims] (1) General formula (1) (Wherein GE is a glycidyl ether group, R ₁ is each independently a hydrogen atom, an alkyl group or a halogen atom having 1 to 6 carbon atoms, R ₂ is a cyclohexyl group or a substituted cyclohexyl group, R ₃ is a hydrogen atom, An epoxy group represented by an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 14 carbon atoms. 2. An epoxy resin composition comprising the epoxy resin according to claim 1 and a curing agent. 3. The curing agent is a polyhydric phenol.
The epoxy resin composition according to the above.