Patent ID: 6280843
Filing Date: 2001-08-28
Classification: B29C,B29K,B32B,C08J,D01F,D21H,H05K,Y10S,Y10T

Abstract:
A wholly aromatic polyamide fiber sheet comprising,(A) 60 to 96% by weight of wholly aromatic polyamide staple fibers comprising wholly aromatic polyamide crystals having apparent crystal sizes determined from a wide angle X-ray diffraction intensity curve in accordance with Scherrer's equation and satisfying the requirements (1), (2), (3) and (4):(1) the crystal size (A) in a (110) plane is 7.5 nm (75 angstroms) or more,(2) the crystal size (B) in a (200) plane is 8.2 nm (82 angstroms) or more,(3) the product (A.times.B) of the crystal size (A) and the crystal size (B) is 61.50 to 630.00, andhaving a thermal linear expansion coefficient within the range of from -1.0.times.10.sup.-6 /.degree. C. to -7.5.times.10.sup.-6 /.degree. C., and(4) when the wholly aromatic polyamide stable fibers in an amount of 2 g are cut to a short length of 1 mm or less, immersed in 50 ml of a distilled water, and heat-treated in an autoclave at a temperature of 121.degree. C. under a pressure of 2 kg/cm.sup.2 G, to extract impurity ions from the fibers; the extracted impurity ion-containing water is subjected to an ICP analysis and to a chromatographic analysis to determine the amount of the extracted impurity sodium, potassium and chlorine ions per liter of the extracted impurity ion-containing water; and the extracted impurity ions satisfy the requirements (a), (b) and (c):(a) the amount of the extracted sodium ions is not more than 40 mg/liter,(b) the amount of the extracted potassium ions is not more than 3.0 mg/liter, and(c) the amount of the extracted chlorine ions is not more than 7.5 mg/liter, and(B) 4 to 40% by weight of at least one member selected from the group consisting of organic resin binders and heat-resistant organic polymer fibers.