Abstract: A resin composition which is capable of forming a film that has excellent heat resistance and slidability/bendability; a protective film for circuits, which uses the resin composition; and a dry film or the like which comprises the protective film are provided. Other aspects are a circuit board and a multilayer circuit board, each of which has excellent heat resistance and slidability/bendability. Furthermore, a protective film for circuit boards is provided, which is arranged in contact with a circuit of a printed wiring board, and contains a polyoxazolidone resin that has a weight average molecular weight of 3×104 or more.

Abstract: A resin composition which is capable of forming a film that has excellent heat resistance and slidability/bendability; a protective film for circuits, which uses the resin composition; and a dry film or the like which comprises the protective film are provided. Other aspects are a circuit board and a multilayer circuit board, each of which has excellent heat resistance and slidability/bendability. Furthermore, a protective film for circuit boards is provided, which is arranged in contact with a circuit of a printed wiring board, and contains a polyoxazolidone resin that has a weight average molecular weight of 3×104 or more.

Abstract: A phosphorous epoxy resin of the invention being obtainable by reacting an organophosphorus compound, a trifunctional epoxy resin and a bifunctional epoxy resin optionally together with a bifunctional phenol compound. A flame-resistant highly thermally stable epoxy resin composition is also provided, which contains the above phosphorous epoxy resin. A cured product with excellent flame resistance and thermal stability can be obtained from the phosphorous epoxy resin, which cured product is useful as a prepreg or a laminate.

Abstract: An epoxy resin composition which exhibits a low dielectric constant and a low dielectric dissipation factor as well as an excellent working susceptibility after its curing is provided. The epoxy resin composition contains at least one member selected from a novolak resin (A) prepared by condensing formalin and an alkylphenol compound; and an epoxy resin (B) prepared by glycidylating said novolak resin (A) with an epihalohydrin.

Abstract: A heat-resistant, flame-retardant epoxy resin composition is provided by combining or reating members selected from a polyfunctional epoxy resin, a bisphenol type epoxy resin, a highly halogenated bisphenol type epoxy resin, a low halogenated bisphenol type epoxy resin, and a halogenated bisphenol. The composition is suitable as a laminate useful for printed circuit boards.

Abstract: An epoxy resin comprising an active hydrogen compound having at least three active hydrogen atoms capable of reacting with an epoxy group in its molecule or butadine or isoprene as a main monomer is modified with an oligomer having on average at least 1.5 equivalents of active hydrogen capable of reacting with an epoxy group in its molecule. An epoxy resin modified with a bisphenol and a compound having active hydrogen or acid anhydride groups capable of reacting with an epoxy group is also provided. A toner containing the epoxy resin as a binder is useful in electrostatography.