Abstract: Provided are a resin composition comprising 100 parts by mass of the polymer having an alicyclic structure at least in a part of a repeating structural unit and 0.05 to 5 parts by mass of a hindered amine compound having a carbon atom at a ratio of from 67% by weight to 80% by weight in the molecular structure and having a molecular weight of from 500 to 3500, a novel piperidine derivative having a piperidylaminotriazine skeleton, a molded product such as an optical component obtained by molding the resin composition, and an optical pickup device which employs the optical component.

Abstract: An aliphatic polyester copolymer comprising an aliphatic carbonate unit (a) and an aliphatic polyester unit (b), and a molded body composed of said aliphatic polyester copolymer. The aliphatic polyester copolymer is excellent in heat resistance while having adequate mechanical properties and properties in the molten state.

Abstract: An aliphatic polyester copolymer comprising an aliphatic carbonate unit (a) and an aliphatic polyester unit (b), and a molded body composed of said aliphatic polyester copolymer. The aliphatic polyester copolymer is excellent in heat resistance while having adequate mechanical properties and properties in the molten state.

Abstract: The invention relates to a process for producing an aliphatic polyester excellent in stability which includes subjecting an aliphatic polyester containing at least 50% of an aliphatic hydroxycarboxylic acid unit, obtainable by solid-phase polymerization under a flowing gas in the presence of a volatile catalyst so as to have a desired weight average molecular weight within the range of 50,000 to 1,000,000, to a heat treatment at a temperature equal to or higher than the reaction temperature of the solid-phase polymerization under a flowing gas with maintaining the aliphatic polyester in a solid state. According to the process of the invention, an aliphatic polyester excellent in stability at molding and storage stability is obtained.

Abstract: A process for producing aliphatic polyester wherein a crystallized aliphatic polyester prepolymer formed from an aliphatic dihydric alcohol and an aliphatic dicarboxylic acid and having a weight-average molecular weight of 2,000 to 100,000 is caused to undergo solid-phase polymerization in the presence of a volatile catalyst to make an aliphatic polyester having a weight-average molecular weight of 50,000 to 1,000,000. This process is more efficient than any prior process calling for a complicated step for catalyst removal, since it enables the removal of the catalyst from the reaction system during and/or after solid-phase polymerization. The polyester is comparable in stability to any aliphatic polyester having any catalyst removed therefrom.

Abstract: The invention provides a process for producing high-molecular aliphatic polyesters capable of being substitutes for general-purpose resins that are required to have high toughness, in a simplified manner and at a high volume efficiency. Specifically, in the process, used as the starting material is an easily-available, low-molecular aliphatic polyester prepolymer to be prepared through polycondensation of inexpensive materials of an aliphatic hydroxycarboxylic acid such as lactic acid, glycolic acid or the like, an aliphatic polyalcohol such as butanediol or the like, and an aliphatic polycarboxylic acid such as succinic acid or the like, and the starting prepolymer is crystallized and thereafter polycondensed in a solid phase in the presence of a catalyst to give the intended, tough and high-molecular aliphatic polyester.

Abstract: A biodegradable aliphatic polyester elastomer which has rubber-like elasticity, hardness of 80 or less in accordance with ASTM D 676-58T, and elastic modulus from 1.times.10.sup.5 Pa to 1.times.10.sup.8 Pa at 25.degree. C., and decomposes with ease in the natural environment, under composting conditions or under hydrolysis conditions. The biodegradable aliphatic elastomer can be obtained by crosslinking aliphatic polyester containing aliphatic unsaturated polybasic acid as a polymer constituting ingredient and having a weight average molecular weight of 15,000 or more.

Abstract: A degradable polymer and a process for preparing the degradable polymer which has a structure resulting from combination of a star-shaped polymer comprising a polyfunctional base compound of polycarboxylic acid having three or more carboxyl groups and/or anhydride of the same or aliphatic polyhydric alcohol having three or more hydroxyl groups and a unit of aliphatic hydroxycarboxylic acid, with aliphatic polyhydric alcohol having two or more hydroxyl groups or polycarboxylic acid having two or more carboxyl groups or anhydrides of the same. The degradable polymer leads to remarkably low coloration as compared with a polymer comprising polysaccharide as a polyfunctional base compound, has high melt tension as compared to common aliphatic polyester is excellent in processability on various molding methods, foam molding and blow molding in particular, and high transparency.

Abstract: A degradable copolymer obtained by heat-dehydration reaction of aromatic polycarbonate and aliphatic polyester in the presence of a catalyst, has degradability which cannot be exhibited by common aromatic polycarbonate, transparency equal to polycarbonate, thermal resistance which cannot be exhibited by common aliphatic polyester, melt flowability superior to common aromatic polycarbonate and other excellent characteristics, and thus can be widely used for processed articles which require severe properties.

Abstract: A preparation process of a degradable copolymer comprising carrying out dehydration polycondensation of polysaccharide (A) with one or more compounds (B) selected from the group consisting of:(b1) hydroxycarboxylic acid,(b2) polyhydroxycarboxylic acid,(b3) aliphatic polyhydric alcohol and aliphatic polybasic acid, and(b4) aliphatic polyester derived from aliphatic polyhydric alcohol and aliphatic polybasic acid.A copolymer having a high molecular weight, excellent toughness, transparency and heat resistance, and additionally having a high melt tension can be obtained with a reaction time less than a half of the conventional process. The copolymer obtained by the invention is a material suited for injection molding, extrusion, calendaring, blow forming, balloon forming, vacuum forming and foaming. Particularly, the copolymer obtained by the invention has a high melt tension and thus the molten copolymer is difficult to sag and flow and can be processed with ease into foams and blow bottles.