发明授权
US5442003A Para-aramid dope of low degree of polymerization, para-aramid fiber and para-aramid pulp produced therefrom and processes for producing the same 失效
低聚合度的对位芳族聚酰胺涂料,由其生产的对位芳族聚酰胺纤维和对位芳族聚酰胺纸浆及其制备方法

Para-aramid dope of low degree of polymerization, para-aramid fiber and
para-aramid pulp produced therefrom and processes for producing the same
摘要:
A para-aramide dope of low degree of polymerization exhibiting an optical anisotropy containing 4-10% by weight of a para-aramide having an inherent viscosity of 1.0-2.5 dl/g and 2-10% by weight of an alkali metal chloride or an alkaline earth metal chloride in a polar amide solvent;a para-aramide fiber obtained by spinning the above-mentioned para-aramide dope of low degree of polymerization;a para-aramide pulp obtained by cutting the above-mentioned para-aramide fiber into a short fiber, mechanically fibrillating the short fiber with a high shearing force and thereafter drying the fibrillated short fiber;a process for producing a para-aramide fiber which comprises adding 0.94-0.99 mole of a para-oriented aromatic dicarboxylic acid halide to 1.00 mole of a para-oriented aromatic diamine in a polar amide solvent in which 2-10% by weight of an alkali metal chloride or an alkaline earth metal chloride is dissolved, carrying out a polymerization at a temperature of -20.degree. C. to 50.degree. C. to form a para-aramide dope of low degree of polymerization exhibiting an optical anisotropy and having a para-aramide concentration of 4-10% by weight, and spinning the dope; anda process for producing a para-aramide pulp which comprises cutting the above-mentioned para-aramide fiber into a short fiber, mechanically fibrillating the short fiber with a high shearing force, and thereafter drying the fibrillated short fiber.
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