Abstract: Provided is a curable resin composition which: has high levels of dielectric characteristics required in an electrically insulating material application compatible with a high frequency; provides a cured article excellent in low water absorption rate and low linear expansion rate; and is excellent in wire embedding flatness and resin fluidity. Specifically, provided is an aromatic polyester obtained by condensing (a) an aromatic oxycarboxylic acid, (b) an aromatic polyvalent carboxylic acid or an aromatic polyhydric hydroxy compound, and (c) an aromatic monohydroxy compound or an aromatic monocarboxylic acid. Also provided is a curable resin composition containing the aromatic polyester (A), an epoxy resin (D) having two or more epoxy groups per molecule, and a curing accelerator (E).

Abstract: A water-soluble thermally polymerizable oxetane resin composition comprises (A) a water-soluble oxetane compound and (B) at least one heteropolyacid compound selected from heteropolyacids and heteropolyacid salts. The water-soluble oxetane compound may contain one or more oxetane functional groups in the molecule and one or more alcoholic OH groups in the molecule. The heteropolyacids include phosphotungstic acid, phosphomolybdic acid, silicotungstic acid, silicomolybdic acid or mixtures thereof. The heteropolyacid salts include phosphotungstic acid salts, phosphomolybdic acid salts, silicotungstic acid salts, silicomolybdic acid salts or mixtures thereof.

Abstract: Disclosed is a cationically polymerizable composition which shows improved storage stability and whose polymerization initiation temperature or curing temperature is controlled. In the case where the composition is thermosetting, it yields a cured product of three-dimensional structure excellent in mechanical properties, electrical properties, adhesive properties, heat resistance, moisture resistance, chemical resistance, and the like. The cationically polymerizable composition comprises a cationically polymerizable compound selected from vinyl compounds, lactones, cyclic ethers, and the like, a heteropolyacid selected from phosphotungstic acid, phosphomolybdic acid, silicotungstic acid, silicomolybdic acid, and the like as a cationic polymerization initiator, and a stabilizer selected from heteropolyacid salts as an inhibitor of cationic polymerization.

Abstract: Disclosed is a thermosetting resin composition of excellent low-temperature curability comprising an oxetane compound and also disclosed is a cured article obtained therefrom. The thermosetting resin composition comprises an oxetane compound (A) containing two or more oxetane functional groups in the molecule represented by the following general formula (1) and a heteropolyacid (B) as essential components. A cured article obtained by heat curing of this composition shows excellent mechanical properties, electrical properties, adhesive properties, resistance to heat, moisture, and chemicals, and the like. In formula (1), R1 is a hydrogen atom, alkyl group of 1 to 6 carbon atoms, fluorine atom, fluoroalkyl group of 1 to 6 carbon atoms, allyl group, aryl group, aralkyl group, furyl group, or thienyl group.

Abstract: Disclosed is a thermosetting resin composition of excellent low-temperature curability comprising an oxetane compound and also disclosed is a cured article obtained therefrom. The thermosetting resin composition comprises an oxetane compound (A) containing two or more oxetane functional groups in the molecule represented by the following general formula (1) and a heteropolyacid (B) as essential components. A cured article obtained by heat curing of this composition shows excellent mechanical properties, electrical properties, adhesive properties, resustance to heat, moisture, and chemicals, and the like. In formula (1), R1 is a hydrogen atom, alkyl group of 1 to 6 carbon atoms, fluorine atom, fluoroalkyl group of 1 to 6 carbon atoms, allyl group, aryl group, aralkyl group, furyl group, or thienyl group.

Abstract: Disclosed is a cationically polymerizable composition which shows improved storage stability and whose polymerization initiation temperature or curing temperature is controlled. In the case where the composition is thermosetting, it yields a cured product of three-dimensional structure excellent in mechanical properties, electrical properties, adhesive properties, heat resistance, moisture resistance, chemical resistance, and the like. The cationically polymerizable composition comprises a cationically polymerizable compound selected from vinyl compounds, lactones, cyclic ethers, and the like, a heteropolyacid selected from phosphotungstic acid, phosphomolybdic acid, silicotungstic acid, silicomolybdic acid, and the like as a cationic polymerization initiator, and a stabilizer selected from heteropolyacid salts as an inhibitor of cationic polymerization.