Abstract: A breathable, hydrolyzable, porous film having long-term stability in mechanical properties which is obtained by the process comprising adding from 40 to 250 parts by weight of a finely-powdered filler having an average particle size of from 0.3 to 4 .mu.m to 100 parts by weight of a polylactic acid-based resin composition comprising from 80 to 95% by weight of polylactic acid or a lactic acid-hydroxycarboxylic acid copolymer and from 5 to 20% by weight of a plasticizer comprising a citric acid ester, melting and film-forming the resultant mixture, and successively stretching the thus-obtained film 1.1 times or more at least in the direction of the axis; and which is consequently useful as a material for leakproof films of sanitary materials such as a paper diaper and packaging materials, and does not accumulate as wastes because of hydrolyzability in the natural environment in the case of being abandoned after use.

Abstract: A breathable, hydrolyzable, porous film which is obtained by the process comprising adding from 40 to 250 parts by weight of a finely-powdered filler having an average particle size of from 0.3 to 4 .mu.m to 100 parts by weight of a polylactic acid-based resin composition comprising from 80 to 100% by weight of polylactic acid or a lactic acid-hydroxycarboxylic acid copolymer and from 0 to 20% by weight of a plasticizer, melting and film-forming the resultant mixture, and successively stretching the thus-obtained film 1.1 times or more at least in the direction of the axis; and which is consequently useful as a material for leakproof films of sanitary materials such as a paper diaper and packaging materials, and does not accumulate as wastes because of hydrolyzability in the natural environment in the case of being abandoned after use.

Abstract: A surgical filament which has a surface coated with at least one N-long chain monoacylated basic amino acid having an aliphatic acyl group of from 6 to 22 carbon atoms or with a composition containing at least one of said N-long chain monoacylated basic amino acid, and has improved surface-slipping characteristics such as the ability to be passed through tissue and tie down property.

Abstract: The present invention provides a nylon composition having increased hydrolyzability which is obtained by physically mixing 100 parts by weight of a nylon with 1 to 50 parts by weight of at least one polymer selected from the group consisting of polylactic acid, polyglycolic acid and a copolymer containing 50 mol % or more of a lactic acid unit or a glycolic acid unit as a repeating unit in its chain; and a method for increasing the hydrolyzability of a nylon by preparing such a composition. High hydrolyzability can be imparted to the nylon inherently having extremely low hydrolyzability without impairing its original mechanical strength. Therefore, various molded articles made from the nylon can be hydrolyzed under natural circumstances, and thus the wastes are not stored.

Abstract: A biocompatible polyester which has improved hydrolyzability obtained by bonding saccharide to the structure of a polymer consisting of a glycolic acid unit and/or a lactic acid unit, and a process for Preparing the biocompatible polyester are disclosed.

Abstract: A degradable polymer network obtained by adding from 0.2 to 10 parts by weight of a foaming agent to 100 parts by weight of a polylactic acid-base resin composition comprising from 80 to 100% by weight of polylactic acid or a lactic acid-hydroxycarboxylic acid copolymer and from 0 to 20% by weight of a plasticizer, conducting melt-foaming extrusion of resulting mixture, and opening the foam cells in the extrudate. The high polymer network is characterized in suitable flexibility and hydrolyzability and thus useful as a material for absorbing of oils and body fluids, screens for sunlight, heat-insulating materials, filter media and packaging materials; and does not accumulate as industrial wastes because of hydrolyzability in the natural environment, even though abandoned after use.

Abstract: A degradable polymer network obtained by adding from 0.2 to 10 parts by weight of a foaming agent to 100 parts by weight of a polylactic acid-base resin composition comprising from 80 to 100% by weight of polylactic acid or a lactic acid-hydroxycarboxylic acid copolymer and from 0 to 20% by weight of a plasticizer, conducting melt-foaming extrusion of resulting mixture, and opening the foam cells in the extrudate. The high polymer network is characterized in suitable flexibility and hydrolyzability and thus useful as a material for absorbing oils and body fluids, screens for sunlight, heat-insulating materials, filter media and packaging materials; and does not accumulate as industrial wastes because of hydrolyzability in the natural environment, even though abandoned after use.

Abstract: A styrene derivative carrying N-acethylchito-oligosaccharide chains, a polystyrene derivative carrying N-acetylchito-oligosaccharide chains on the side chains as well as a method for preparing these compounds are herein disclosed. The method for preparing the styrene derivative comprises reacting N-acetylchito-oligosaccharide lactone with vinylbenzylamine or a derivative thereof while the method for preparing the polystyrene derivative comprises polymerizing the styrene derivative. These derivatives can be employed as biomedical materials, in particular as materials for cell culture.

Abstract: In preparing bioabsorbable polyesters containing glycolic acid unit and/or lactic acid unit by the polymerization of glycolide and/or lactide, compositions comprising polyester-silicone copolymers obtained by conducting polymerization in the presence of silicones and the effect of merely mixing the above bioabsorbable polyesters with certain kind of silicones upon the modification, thereby attaining flexibility in particular, of the bioabsorbable polyesters, are disclosed.

Abstract: The invention relates to a process for the preparation of a bioabsorbable polyester comprising reacting said polyester under reduced pressure in the reaction system while maintaining said polyester in the molten state during the second half of the polymerization reaction or after completion of the reaction and obtaining said polyester which contain almost no residue of unreacted monomers and volatile ingredients of low molecular weight.

Abstract: A process for copolymerizing lactide and glycolide by using a specific amount of stannous octoate as a catalyst in the presence of a polymerization regulator at temperature of 200.degree.-230.degree. C. to prepare dl-lactic acid-glycolic acid-copolymers which contain 50-60 mol % of a dl-lactic acid unit and 40-50 mol % of a glycolic acid unit and have inherent viscosity of 0.4-0.6 in chloroform.