Abstract: An unsaturated polyester resin composition containing 8 to 20% by weight of unsaturated polyester resin, 4 to 12% by weight of liquid thermoplastic resin, 8 to 20% by weight of glass fiber, and 50 to 75% by weight of inorganic filler, the unsaturated polyester resin containing 5.10 to 5.90 mmol/g of double bond group concentration, 1.50 to 2.50 mmol/g of ether linkage group concentration, 1.05 to 1.30 mmol/g of isopropylidene linkage group concentration, 2.50 to 3.50 mmol/g of ethylene linkage group concentration, and 3.20 to 3.60 mmol/g of methylene linkage group concentration per 1 g of unsaturated polyester.

Abstract: An unsaturated polyester resin composition containing 8 to 20 % by weight of unsaturated polyester resin, 4 to 12 % by weight of liquid thermoplastic resin, 8 to 20 % by weight of glass fiber, and 50 to 75 % by weight of inorganic filler, the unsaturated polyester resin containing 5.10 to 5.90 mmol/g of double bond group concentration, 1.50 to 2.50 mmol/g of ether linkage group concentration, 1.05 to 1.30 mmol/g of isopropylidene linkage group concentration, 2.50 to 3.50 mmol/g of ethylene linkage group concentration, and 3.20 to 3.60 mmol/g of methylene linkage group concentration per 1 g of unsaturated polyester.

Abstract: A process for producing a bistrimellitic imide of the formula (2) ##STR1## wherein X is an aliphatic group having at least 2 carbon atoms, an alicyclic group or an aromatic group,which comprises reacting a trimellitic anhydride with a diamine of the formula (1)H.sub.2 N--X--NH.sub.2 (1)wherein X is as defined above, in the presence of a solvent mixture containing an aprotic polar solvent and an aromatic hydrocarbon solvent which can be distilled azeotropically with water, the amount of the aromatic hydrocarbon solvent being 10 to 90% by weight based on the total weight of these two solvents.

Abstract: A copolyesterimide composed of bis-trimellitimide units, 2,6-naphthalenedicarboxylic acid units, hydroquinone units and p-hydroxybenzic acid units. This copolyesterimide is melt-processable, and excels in heat resistance and mechanical properties.

Abstract: A process for the production of a molded article of a thermosetting resin composition by injection of a raw material component mixture containing an active hydrogen compound (A) with a polymerizable vinyl monomer (B) and a raw material component containing a polyisocyanate compound (C) into a mold charged with a fiber (D), and a material which is a mixture of the active hydrogen compound (A) with the polymerizable vinyl monomer (B) or a combination of the mixture with the polyisocyanate compound (C).

Abstract: A melt-processable copolyester consisting essentially of:a structural unit (I) of formula (1-1) ##STR1## and formula (1-2) ##STR2## wherein the amount of the species of formula (1-2) is 5 to 95 mole % of the structural unit (I),a structural unit (II) of formula (2)--O--X--O-- (2)wherein X is at least one selected from the group consisting of ##STR3## and a structural unit (III) of formula (3)--O--Y--CO-- (3)wherein Y is at least one selected from the group consisting of ##STR4## the proportion of the structural unit (III) being 10 to 80 mole % of the structural units (I)+(II)+(III) in total, the structural unit (I) being substantially equimolar to the structural unit (II) and inherent viscosity (ln .eta..sub.rel)/C, measured in a concentration of 0.16 g/dl in pentafluorophenol at 60.degree. C., being not less than 0.5 dl/g.

Abstract: A melt-processable copolyester comprising:a structural unit (I) of the formula (1), ##STR1## a structural unit (II) of the formula (2),--OC--X--CO-- (2)wherein X is at least one member selected from the group consisting of ##STR2## a structural unit (III) of the formula (3)--O--Y--O-- (3)wherein Y is at least one member selected from the group consisting of ##STR3## and a structural unit (IV) of the formula (4)--O--Z--CO-- (4)wherein Z represents at least one member selected from the group consisting of ##STR4## the ratio of the structural unit (IV) (III) to the structural units [(I)+(II)+(III)+(IV)] in total being 5 to 80 mole%, the structural units [(I)+(II)] being substantially equimolar to the structural unit (III), the ratio of the structural unit (I) to the structural units [(I)+(II)] in total being 10 to 90 mole %, and the copolyester having an inherent viscosity (ln .eta..sub.rel)/C, measured in a concentration of 0.16 g/dl in pentafluorophenol at 60.degree. C., of not less than 0.3 dl/g.

Abstract: The invention relates to fiber-reinforced unsaturated polyester resin compositions comprising an unsaturated polyester (A) obtained from a dicarboxylic acid containing unsaturated dicarboxylic acid or its anhydride, or an anhydride of the dicarboxylic acid and a polyhydric alcohol, a polyisocyanate (B), a polymerizable vinyl monomer (C), and a fiber (D), which produce molded articles having excellent impact resistance and improved moldability.

Abstract: A process for producing an oligoester which comprises:(a) the step of reacting isophthalic acid and propylene oxide in a reaction medium in the presence of a specific catalyst comprising a tetraalkyl ammonium compound to prepare an oligoester, and(b) the step of removing volatile components from the resulting oligoester by heating the oligoester at a temperature of 180.degree.-280.degree. C. is disclosed. The oligoester is used as an intermediate for preparing unsaturated polyesters.