| 摘要 |
PURPOSE:To obtain a transparent aramid film, by biaxially drawing a coagulated and washed film in a wet state, drying and heat-treating the drawn film in a state of limited shrinkage, having improved mechanical performance as well as dimensional stability without causing curls. CONSTITUTION:A film, obtained by casting an optically anisotropic dope consisting of poly(p-phenylene terephthalamide) having >=3.5, preferably >=4.5 inherent viscosity and sulfuric acid in >=95wt% concentration on a support surface, converting the above-mentioned dope into an optical isotropic dope by moisture absorption and/or heating, coagulating the dope (preferably with dilute sulfuric acid in >=10wt% concentration at <=10 deg.C), washing the coagulated dope, biaxially drawing the coagulated film in a wet state at >=1.1 times, drying the film in a state of limited shrinkage of the film and heat-treating the dried film at >=350 deg.C and having at least 10% elongation and at least 1,000kg/mm<2> Young's modulus in all the directions parallel to the film surface, <=3.5X10<-5>mm/ mm/%RH moisture absorption expansion coefficient and >=60% light transmittance at 600nm wavelength. |
