Mitsubishi Denki Kabushiki Kaisha

Toshiharu Ando

Masaru Tsuchihashi

Kazuo Yasuda

Yoshifumi Itabashi

Fumio Nogami

A novel epoxy resin composition is comprised of a mixture of a cyclic epoxide type epoxy resin having an epoxy equivalent of 200 or below and a phenoxy resin having a molecular weight of approximately 30,000, a curing agent, and an inorganic filler. This resin composition is useful in the fabrication of cast insulators to be employed in electric machines.

Epoxy resin composition

A novel epoxy resin composition is prepared by first mixing 100 parts by weight of an epoxy resin having an epoxy equivalent of no more than 200 with 0.5-10 parts by weight of a phenoxy resin to form a uniform mixture, then blending the mixture with a curing agent (i.e., a condensation product of a polybasic carboxylic acid and bisphenol A) and an inorganic filler. The epoxy resin composition has a suitable degree of rigidity and softness within the molecular chain without sacrificing its resistance to heat or thermal shock and will not cause precipitation of any portion of the filler in the resin composition. This resin composition is useful in the making of cast insulators employed in electric machines.

An epoxy resin composition consisting essentially of a heat-melted mixture obtained by mixing under heat 100 parts by weight of an epoxy resin having an epoxy equivalent of 200 or below and 0.5 to 10 parts by weight of polysulfone resin; a curing agent; and an inorganic filling material.

An epoxy resin composition consisting essentially of an epoxy resin having an epoxy equivalent of 200 or lower, a mixture of polybasic carboxylic acid anhydride and aromatic ester as a curing agent, and inorganic powder as a filler.

An epoxy resin composition which comprises:

An epoxy resin composition which comprises an epoxy resin having an epoxy equivalent of at most 200; a condensation mixture (A) of a polybasic carboxylic acid anhydride, a bisphenol A having the formula: ##STR1## and a polyhydric alcohol, as a curing agent; and an inorganic powder, as a filler.

An epoxy resin composition which comprises a mixture (a) obtained by mixing 100 parts by weight of a polybasic carboxylic acid anhydride with from 10 to 70 parts by weight of a compound having at least two phenol groups, an epoxy resin having at least two epoxy groups in the molecule, a catalyst, and an inorganic powder as a filler.

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Itami, Japan

Toshiharu Ando