Mitsui Petrochemical Industries, Ltd.

Nobuyuki Takeda

Tadao Iwata

Takayuki Nakano

Shigeru Katayama

Disclosed are a polynuclear polyhydric phenol represented by the following general formula [I]: ##STR1## wherein R.sup.1 and R.sup.2 stand for a hydrogen atom or a lower alkyl group, R.sup.3 stands for a hydrogen atom, an alkyl group, an aryl group or a halogen atom, and n is an integer of from 0 to 10, and a polyepoxy compound consisting of a polyglycidyl ether of this polynuclear polyhydric ether. When this polyepoxy compound is combined with a curing agent, a curable epoxy resin composition excellent in the heat resistance characteristics is provided.

Polyglycidyl ethers of polynuclear polyhydric phenols

A high-molecular-weight novolak type substituted phenolic resin having a number average molecular weight of at least 1500 is prepared by reacting (A) (i) a phenol comprised mainly of a bifunctional phenol or (ii) a low-molecular-weight novolak type substituted phenolic resin derived from this phenol and an aldehyde with (B) a chain extender selected from the group consisting of (i) a dimethylolated product of a bifunctional or trifunctional phenol, (ii) a low-molecular-weight resol type substituted phenolic resin derived from a phenol comprised mainly of a bifunctional phenol and an aldehyde, (iii) an aldehyde, (iv) a ketone, (v) a diol and (vi) a dihalide in the presence of an acid catalyst, with the proviso that if the reactant (A) is the phenol (i), the chain extender is the resol type substituted phenolic resin (ii). The molecular weight of this novolak type substituted phenolic resin is much higher than the molecular weights of conventional novolak type phenolic resins, and if this phenolic resin is incorporated into various setting type resins, the heat resistance and mechanical properties of these resins can remarkably be improved.

High-molecular-weight novolak types substituted phenolic resins and

Disclosed is a setting type resin composition comprising (A) a setting type resin and (B) 10 to 200 parts by weight, per 100 parts by weight of said resin (A), of a substantially linear, high-molecular-weight novolak type substituted phenolic resin which comprises a constituent phenol component comprised mainly of a bifunctional phenol and has a number average molecular weight of at least 1500. This resin composition has highly improved heat resistance and mechanical strength characteristics by virtue of incorporation of the high-molecular-weight novolak type substituted phenolic resin, and this improving effect is especially prominent when an epoxy resin is used as the setting type resin.

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Iwakuni, Japan

Nobuyuki Takeda