JPS6241968B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a fast-curing epoxy resin composition with excellent reliability, which is characterized by the use of a resin having nitrogen atoms in its skeleton. In recent years, metal parts and ceramic parts have been rapidly replaced with plastic to reduce weight and cost. These plastics include phenolic resins, polyester resins, epoxy resins, etc. Initially, phenolic resins were used for general purposes, polyester resins were used for electrical purposes, and epoxy resins were used for high-grade insulation. However, in the past few years, with the shift to plastic for high-quality parts and the demand for higher quality plastics, epoxy resins have come into use in large quantities and have become more important as general-purpose resins. In the field of epoxy resin molding materials, in order to respond to this generalization (mass production and lower costs), rationalization is being carried out by shortening molding cycles and automating molding. For example, in the case of molding materials for low-pressure sealing, there has been a shift to faster-curing materials and consideration has been given to fully automated systems by introducing multi-plunger molding machines. A current problem in semiconductor encapsulation applications is that rapid curing of materials reduces reliability. The usual measure taken to improve the curing properties of materials is to increase the amount of curing catalyst, but this curing catalyst is considered a low-molecular impurity in terms of material purity and is a cause of reduced reliability. It is considered. It is also believed that as the material hardens faster, the internal stress of the molded product increases and the adhesion with the insert weakens, reducing reliability. The present invention provides an epoxy resin composition that makes it possible to significantly shorten the processing cycle, particularly an epoxy resin composition that has excellent reliability. The gist of the present invention is that it is a curing catalyst that is not harmful to phenols such as phenol, cresol, xylenol or resorcinol, aniline and forma impurities, and has a stress-relaxing structure. In addition, the epoxy resin used in the present invention has nitrogen atoms/
The higher the epoxy group molar ratio, the better the curability, and the molecular weight is preferably 700 to 1300 (number average molecular weight). A summary of the nitrogen atomic ratio and composition properties of the resin is shown in the table below.

[Table] ○ = Excellent. ◎〓Excellent.
In the present invention, the epoxy resin obtained as described above can be used alone or in combination with other epoxy resins, with appropriate addition of a curing agent and the like. Furthermore, curing accelerators, fillers, pigments, surface treatment agents,
A mold release agent etc. can be added. The other epoxy resins used in the present invention can be all those having epoxy groups, such as bisphenol type epoxy resins, phenol novolak type epoxy resins, cresol novolak type epoxy resins, and triazine nucleus-containing epoxy resins. The curing agent that can be used in the present invention may be anything that reacts with other epoxy resins, such as phenol novolaks such as phenol novolak and orthocresol novolak, tetrachlorophthalic anhydride (TCPA), and hexahydroanhydride. Examples include acid anhydrides such as phthalic acid (HHPA) and tetrahydrophthalic anhydride (THPA), and amines such as dicyandiamide (DDA) and diaminodiphenylmethane (DDM). If you want to further accelerate curing, use dimethylaminomethylphenol, piperazine, 2,3,4,6,7,8,
9,10-octahydropyramide (1,2-
a) Tertiary amines such as azepine, organic phosphine compounds such as octylphosphine, diphenylphosphine, butylphenylphosphine, tricyclohexylphosphine, triphenylphosphine, 2-phenylimidazole (2Z), Curing accelerators such as imidazoles such as 2-ethyl-4-methylimidazole (2E4MZ), 1-benzylimidazole (1BZ), and 2-methylimidazole (2MZ) may also be used. The composition of the present invention can contain fillers, pigments, flame retardants, mold release agents, etc. in addition to the above-mentioned formulations. Examples of fillers used include silica, glass, calcium carbonate, mica, clay, alumina, Examples include inorganic fillers such as asbestos, aluminum hydroxide, and magnesium hydroxide, and organic fillers such as wood flour, crushed cloth, and pulp. The surface of the filler may be modified with a treatment agent. Also, mold release agents such as carnauba wax, stearic acid, stearates, polyethylene wax, etc. can be used. Examples and Comparative Examples To prepare the epoxy resin used in the present invention, formaldehyde (37% formalin) and a catalyst such as oxalic acid are first mixed in a reaction vessel, and then aniline is added dropwise while cooling. Then add phenols and approx.
Heat to 100℃ to perform reflux reaction, then heat to 150℃
A resin co-condensate was obtained by heating and dehydrating to 300°C, and the co-condensate was mixed with methanol and excess epichlorohydrin, and a catalyst: sodium hydroxide (30% aqueous solution) was added dropwise to the mixture, followed by heating at 40°C. The reaction mixture was refluxed under reduced pressure, followed by removal of epichlorohydrin, solvent washing, and water washing under reduced pressure.
A reflux reaction is carried out at 70°C and the desired epoxy resin is obtained by washing with water. An example of a method for producing the first co-condensate is to react with 120 parts by weight of phenol, 80 parts by weight of aniline, 140 parts by weight of formalin (37%), and 2 parts by weight of oxalic acid, and the number average molecular weight is approximately 600. /OH=0.6 was obtained. As a secondary reaction, 1000 parts by weight of epichlorohydrin and 20 parts by weight of methanol were added to 100 parts by weight of the co-condensate.
Parts by weight, sodium hydroxide (30% aqueous solution) primary 5
The ratio was 1 part by weight and 2 parts by weight for the secondary product. Methyl isobutyl ketone (MIBK) was used as a cleaning solvent. The number average molecular weight of the obtained epoxy resin was about 1000. The epoxy resin of the present invention used in this example includes: A: Aniline-modified resorcin cocondensate (N/OH
= 0.3) epoxidized product B: Aniline-modified phenol cocondensate (N/OH
= 0.6), and their number average molecular weight is approximately 1000. Epoxy resins A and B and the curing agent are phenol novolac (number average molecular weight 600: Nippon Kayakusei PN-
100) and filler: 70 parts by weight of crystalline silica (Kamori Mori Sunrex "200"), curing accelerator: 2E4MZ (manufactured by Shikoku Kayaku), surface treatment agent: Silane coupling agent A
-187 (manufactured by Nippon Unicar) 0.5 parts by weight, mold release agent: Hoechstwax OP 0.5 parts by weight, and pigments, etc. were combined to form a composition with the blending ratio shown in Table 1 using a heating roll to form several molding materials. was manufactured. As a comparative example, the other formulations were the same as in the examples, but the epoxy resin was orthocresol novolak type epoxy resin Epiclon N-670 (manufactured by Dainippon Ink Chemical Industry Co., Ltd.,
(number average molecular weight 1000) was used. The evaluation is shown below.
1, and all have superior curability and reliability compared to the comparative examples.

[Table] The numbers are relative comparison scores when the comparison example is 100.
The reliability test is determined by the corrosion rate of aluminum when a molded product incorporating an aluminum simulated element is left in an atmosphere of 2 atm, 121°C, and 100% humidity.

Claims (1)

[Claims] 1. An epoxy resin having the following average structural formula obtained by epoxidizing a co-condensate of phenol, cresol, xylenol or resorcin with phenols, aniline and formaldehyde, a curing agent, a curing accelerator, a filler, Epoxy resin compositions containing pigments, surface treatment agents, mold release agents, or other epoxy resins. n: An integer from 0 to 5 R ₁ : -H, -CH ₃ , -[CH ₃ ) ₂ , -OH