Abstract: This invention provides, as a novel compound suited as an encapsulating material for electronic devices, having a high Tg, being low moisture-absorptive, having a high adhesion and being rich in fluidity, a cyclopentylene compound represented by Formula (I) and its intermediate cyclopentenyl compound represented by Formula (III). In the formula, m is 0 or more, Ar1 and Ar2 are each a phenol residual group, a naphthol residual group or a fluorene derivative residual group, and each contain a hydroxyl group or a glycidyloxyl group.

Abstract: This invention provides a compound suitable as an encapsulating material for electronic devices and having a high Tg, low moisture-absorptive, high adhesion and rich fluidity, which is a cyclopentylene compound represented by Formula (I) and its intermediate cyclopentenyl compound represented by Formula (III). In the formula, m is 0 or more, Ar1 and Ar2 are each a phenol residual group, a naphthol residual group or a fluorene derivative residual group, and each contain a hydroxyl group or a glycidyloxyl group.

Abstract: The present invention provides a resin containing in the backbone chain a structural unit represented by the following Formula (I) or (II), as a novel phenolic resin having a high Tg, a low moisture absorption, a low molding shrinkage, high adhesive properties and high flow properties. The present invention also provides a resin composition and a molding material each containing the above resin, and an electronic component device having a device element encapsulated with it.

Abstract: An epoxy resin composition comprises (A) a biphenyl epoxy resin, (B) a phenolic resin curing agent having a naphthalene structure, (C) a curing accelerator comprising an addition product of a triphenylphosphine and benzoquinone, and (D) an inorganic filler contained in an amount of 85 to 95% by weight based on the total amount of the composition, and a semiconductor device encapsulated by this resin composition.

Abstract: A naphthol-modified phenolic resin having low softening point and good flowability is obtained by allowing a naphthol and a phenol to react with an aldehyde in the presence of an acid catalyst at 60 to 110.degree. C. to obtain a primary reaction mixture, heating the primary reaction mixture in the presence of a strong acid, a super acid or a mixture thereof under ambient pressure at 120 to 180.degree. C. for 1 to 12 hours to obtain a secondary reaction mixture, and subjecting the secondary reaction mixture to vacuum concentration or steam distillation, and the naphthol-modified phenolic resin is suited to use as a curing agent in epoxy resin molding materials for sealing electronic parts.

Abstract: A naphthol-modified phenolic resin having low softening point and good flowability is obtained by allowing a naphthol and a phenol to react with an aldehyde in the presence of an acid catalyst at 60.degree. to 110.degree. C. to obtain a primary reaction mixture, heating the primary reaction mixture in the presence of a strong acid, a super acid or a mixture thereof under ambient pressure at 120.degree. to 180.degree. C. for 1 to 12 hours to obtain a secondary reaction mixture, and subjecting the secondary reaction mixture to vacuum concentration or steam distillation, and the naphthol-modified phenolic resin is suited to use as a curing agent in epoxy resin molding materials for sealing electronic parts.

Abstract: A copolycondensation of a phenol, a naphthol and formaldehyde proceeds smoothly in the presence of an acid and a metallic element selected from the group consisting of transition metallic elements and metallic elements of Group IIa, Group IIIa, Group IVa, Group Va and Group VIa of the Periodic Table, and a naphthol-modified phenolic resin which has a large molecular weight and does not gel is obtained.