摘要:
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.
摘要:
A degradable non-woven fabric obtained from an web formed of lactic acid-based polymer filaments comprising of one or more lactic acid-based polymers selected from a poly (DL-lactic acid) having more than 80 mol % of L-lactic acid units, poly (DL-lactic acid) having more than 80 mol % of D-lactic acid units, L-lactic acid/hydroxycarboxylic acid copolymer having 70 mol % or more of L-lactic acid units, and D-lactic acid/hydroxycarboxylic acid copolymer having 70 mol % or more of D-lactic acid units, and a preparation process of the degradable non-woven fabric which has good dimensional stability and can be degraded and disappeared under natural environment when abandoned.
摘要:
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.
摘要:
Articles matters which can be degraded and disappear in the natural environment are a degradable adhesive film which can be used for surface protection or indication after printing on the film surface and has an adhesive layer on one side of a substrate film obtained from a lactic acid base polymer such as polylactic acid and a lactic acid/hydroxycarboxylic acid copolymer having a molecular weight of 30,000.about.500,000, and a degradable resin composition which is excellent in weatherability and comprises 100 parts by weight of a lactic acid base polymer and 0.001.about.5 parts by weight of one or more additives selected from ultraviolet absorbers and light stabilizers.
摘要:
Articles which can be degraded and disappear in the natural environment are a degradable adhesive film which can be used for surface protection or indication after printing on the film surface and has an adhesive layer on one side of a substrate film obtained from a lactic acid base polymer such as polylactic acid and a lactic acid/hydroxycarboxylic acid copolymer having a molecular weight of 30,000-500,000, and a degradable resin composition which is excellent in weatherability and comprises 100 parts by weight of a lactic acid base polymer and 0.001-5 parts by weight of one or more additives selected from ultraviolet absorbers and light stabilizers.
摘要:
In the preparation of polyester by conducting ring-opening polymerization of a cyclic ester compound in the presence of a hydroxyl compound as a molecular weight regulator in the reaction system, the molecular weight of polyester can be accurately controlled in the desired range by previously estimating the amount of free carboxylic acid contained in the cyclic ester compound and controlling the amount of the hydroxyl compound on the basis of the estimated amount.
摘要:
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.
摘要:
A method for preparing 1,3-dihydroxy-4,6-bis�.alpha.-methyl-.alpha.-.alpha.(4'-hydroxyphenyl)ethyl!benzene represented by the following formula (1): ##STR1## comprising the step of initiating a reaction of resorcin with 4-isopropenylphenol in a mixed solvent which comprises a non-polar solvent and a polar solvent in the presence of an acidic catalyst. The method can easily be handled, ensures a high yield, permits the reduction of impurity content and can provide highly pure 1,3-dihydroxy-4,6-bis�.alpha.-methyl-.alpha.-(4'-hydroxyphenyl)ethyl!benzene. The resulting phenolic compound is useful as, for instance, a branching agent for polycarbonates, polyesters or the like; a raw material for radiant ray-sensitive components for use as resist materials; a raw material for epoxy resins; and a hardening agent for epoxy resins.
摘要:
Herein disclosed is a method for simultaneously preparing a highly pure bisphenol F and/or a bisphenol F for general use and a novolak phenol resin and/or a high molecular weight novolak phenol resin comprising the steps of:(1) a preparation step comprising reacting phenol with formaldehyde in the presence of an acid catalyst and removing the acid catalyst, water and the unreacted phenol from the resulting reaction product to give a crude bisphenol F;(2) a distillation step comprising distilling a part of the crude bisphenol F to give a highly pure bisphenol F, as a distillate, having a binuclear moiety-content of not less than 95% by weight and a novolak phenol resin, as a still-bottom product, having a binuclear moiety-content of not more than 15% by area;(3) a step for mixing the highly pure bisphenol F with the remaining crude bisphenol F to give a bisphenol F for general use; and(4) a step for polymerizing the novolak phenol resin with formaldehyde in the presence of an acid catalyst to give a high molecular weight novolak phenol resin.
摘要:
A process for producing high-purity bisphenol A comprises reacting phenol with acetone in the presence of hydrochloric acid as the catalyst to obtain a product mixture, removing the hydrochloric acid from the product mixture, thereby yielding a liquid mixture, adding water to the liquid mixture, evaporating a water-phenol mixture from the liquid mixture under reduced pressure, thereby cooling the liquid mixture and crystallizing out the adduct of bisphenol A with phenol, and finally recovering bisphenol A from the adduct, wherein an improvement comprises treating the water-phenol mixture with a weakly basic ion-exchange resin and recycling and reusing the treated mixture as the water to be added to the liquid mixture. This process does not causes any troubles such as the corrosion of equipment and the decomposition and discoloration of bisphenol A during distillation.