摘要:
A preparation process of polyhydroxycarboxylic acid having an inherent viscosity of 0.3 dl/g or more by dehydrating polycondensation of lactic acid containing hydroxycarboxylic acid in an organic solvent in the presence or absence of a catalyst, comprising using a hydroxycarboxylic acid raw material which comprises one or more impurities selected from the group consisting of methanol, ethanol, acetic acid, pyruvic acid, fumaric acid, methyl lactate, ethyl lactate and butyl lactate in a total amount of 0.3% by mole or less for the amount of said hydroxycarboxylic acid raw material.
摘要:
A process for preparing polyhydroxycarboxylic acid by conducting dehydration polycondensation of hydroxycarboxylic acids in the presence or absence of a catalyst and in the presence or absence of an organic solvent, comprising using a vertical high viscosity reactor during all or a portion of the dehydration polycondensation steps and conducting hot polycondensation while separating and removing low boiling components. The process can provide high molecular weight polyhydroxycarboxylic acid with ease and cheaply in industry.
摘要:
A purification process for polyhydroxycarboxylic acids which comprises dissolving polyhydroxycarboxylic acid in an water-immiscible phenol or an organic solvent containing said water-immiscible phenol, successively bringing the resulting solution into contact with water which contains an acidic material, separating the organic layer from an aqueous layer, and isolating polyhydroxycarboxylic acid from the organic layer. The process can efficiently remove a catalyst contained in the polyhydroxycarboxylic acid prepared in the presence of the catalyst, does not require polyhydroxycarboxylic acid to be in the form of a solid, and can treat polyhydroxycarboxylic acid in a higher concentration as compared with using chlorinated hydrocarbon as a solvent.
摘要:
A preparation process of polyhydroxycarboxylic acid having an inherent viscosity of 0.3 dl/g or more by dehydrating polycondensation of lactic acid containing hydroxycarboxylic acid in an organic solvent in the presence or absence of a catalyst, comprising using a hydroxycarboxylic acid raw material which comprises one or more impurities selected from the group consisting of methanol, ethanol, acetic acid, pyruvic acid, fumaric acid, methyl lactate, ethyl lactate and butyl lactate in a total amount of 0.3% by mole or less for the amount of said hydroxycarboxylic acid raw material.
摘要:
A preparation process of polyhydroxycarboxylic acid comprising conducting dehydration polycondensation of hydroxycarboxylic acid or an oligomer of the same in a reaction mixture containing said hydroxycarboxylic acid or the oligomer of the same and an organic solvent substantially in the absence of water to give polyhydroxycarboxylic acid having an weight average molecular weight of 50,000 or more, successively mixing the reaction mixture containing said polyhydroxycarboxylic acid with at least one binder selected from the group consisting of (1) polyisocyanate compound, (2) polybasic acid anhydride, (3) cyclic imino ester, (4) cyclic imino ether, (5) aromatic hydroxycarboxylic acid, (6) polyamino compound, (7) polyhydric alcohol, (8) epoxy compound, (9) polyfunctional aziridine compound, (10) lactam, (11) lactone, and (12) diethylene glycol bischloroforate, and reacting to obtain polyhydroxycarboxylic acid having a weight average molecular weight of 100,000 or more the polyhydroxycarboxylic acid which is obtained by the process has a weight average molecular weight of 100,000 or more, has satisfactory mechanical strength in the form of molded articles and is useful as a degradable polymer for substituting medical materials and general purpose resins.
摘要:
A process for producing continuously an aromatic polycarbonate oligomer by reacting an aromatic dihydroxy compound and an alkali metal base or an alkaline earth metal base with a carbonyl halide compound comprises:(1) feeding continuously to a tank reactor an aromatic dihydroxy compound, water, a molecular weight controlling agent, a polymerization catalyst, a carbonyl halide compound, and an organic solvent, and an alkali metal base or an alkaline earth metal base in an amount of 1.15-1.6 equivalents based on the aromatic dihydroxy compound,(2) carrying out the reaction with a residence time as defined by the following formula,log Y
摘要翻译:通过使芳族二羟基化合物和碱金属碱或碱土金属碱与羰基卤化合物反应来连续生产芳族聚碳酸酯低聚物的方法包括:(1)连续地向罐式反应器中加入芳族二羟基化合物,水, 分子量控制剂,聚合催化剂,羰基卤化合物和有机溶剂,碱金属碱或碱土金属碱的用量为1.15-1.6当量,基于芳族二羟基化合物,(2)进行 具有如下式所定义的停留时间的反应log Y <-2.19X + 1.84(0.0005≤X<0.84,1 = Y <69)其中X是聚合催化剂的量,以 摩尔%,基于每单位时间供给的芳族二羟基化合物的摩尔量,Y为停留时间(分钟),(3)从反应器中连续取出反应混合物,得到具有 数均分子量为1,000〜10,000。 通过芳族聚碳酸酯低聚物的缩聚制备芳族聚碳酸酯。
摘要:
A purification process of a polyhydroxycarboxylic acid for efficiently removing a catalyst with a simple method from solid polyhydroxycarboxylic acid by bringing the solid polyhydroxycarboxylic acid which is obtained by a catalytic reaction and has an inherent viscosity of 0.1.about.5.0 dl/g into contact with an acid substance in the presence of a hydrophilic organic solvent. Also disclosed is a polyhydroxycarboxylic acid prepared by direct dehydration polymerization having an extremely reduced content of residual catalyst.
摘要:
A preparation process of solid polyhydroxycarboxylic acid comprising subjecting an organic solvent solution of polyhydroxycarboxylic acid to cooling.cndot.solidification and grinding. The preparation process can provide high molecular weight solid polyhydroxycarboxylic acid with ease and cheaply, can be converted with ease to a continuous system, and is useful in industry.
摘要:
A moldable polyimide resin composition which has melt-flowability and excellent processability in addition to essential heat-resistant of polyimide and comprises an aromatic bisimide compound and polyimide resin. A further aspect relates to a carbon fiber reinforced polyimide resin composition which has excellent mechanical strengths and comprises a carbon fiber coated with aromatic bisimide compound on the surface and the polyimide resin. A still further aspect relates to a novel bisimide compound which is very useful as the aromatic bisimide compound in the composition.
摘要:
A moldable polyimide resin composition which has melt-flowability and excellent processability in addition to essential heat-resistant of polyimide and comprises an aromatic bisimide compound and polyimide resin. A further aspect relates to a carbon fiber reinforced polyimide resin composition which has excellent mechanical strengths and comprises a carbon fiber coated with aromatic bisimide compound on the surface and the polyimide resin. A still further aspect relates to a novel bisimide compound which is very useful as the aromatic bisimide compound in the composition.