Abstract: A heat-resistant fiber paper-like sheet comprises 40 to 97% by mass of heat-resistant organic synthetic polymers staple fibers, 3 to 60% by mass of heat resistant organic synthetic polymer fibrid and or an organic resin binder, in a portion of the staple fibers, each staple fiber having two flat end faces having an inclining angle of 10 degrees or more from a plane crossing the fiber axis at a right angles, and is useful as a base material for laminate materials for electrical circuit boards.

Abstract: A heat-resistant fiber paper sheet which is formed from staple fibers made from a heat-resistant organic polymer, undrawn or low ratio drawn para-aromatic polyamide staple fibers, and an organic resin binder and/or fibrids comprising a heat-resistant organic polymer as main components, wherein the amount of said staple fibers is 45 to 97 percent by weight based on the total amount of said heat-resistant fiber paper sheet; the total amount of said organic resin binder and/or said fibrids is 3 to 55 percent by weight based on the total amount of said heat-resistant fiber paper sheet; and said organic resin binder is cured, and/or said undrawn or low ratio drawn para-aromatic polyamide staple fibers and said fibrids are partially softened, deformed and/or melted to exhibit the actions of binders.

Abstract: A heat-resistant fiber paper-like sheet comprises 40 to 97% by mass of heat-resistant organic synthetic polymers staple fibers, 3 to 60% by mass of heat resistant organic synthetic polymer fibrid and or an organic resin binder, in a portion of the staple fibers, each staple fiber having two flat end faces having an inclining angle of 10 degrees or more from a plane crossing the fiber axis at a right angles, and is useful as a base material for laminate materials for electrical circuit boards.

Abstract: A wholly aromatic polyamide (aramid) fiber synthetic paper sheet includes 70-96 wt % of an aramid staple fiber component which includes 30 wt % or more of a para-type aramid staple fibers each having two or more annular projections spaced from each other and having an average ratio R/&ggr; of the largest diameter R of the annular projections to the smallest diameter &ggr; of the annular projection-free portions of the staple fiber, of 1.1 or more, and 4-30 wt % of a binder component, namely a resinous binder and/or heat resistant fibrids.

Abstract: A heat resistant fiber sheet composed of staple fibers consisting of a heat resistant organic high molecular polymer and fibrids consisting of a heat resistant organic high molecular polymer as main components, having excellent heat resistance, dimensional stability to heat, interlaminar peeling strength, electric insulation resistance under a high humidity, etc., and also good resin impregnating property in spite of having a high bulk density, and especially suitable for a base substrates for an electric insulating material and a laminate for an electric circuit, is obtained by setting the amount of the staple fibers occupying in the total amount of the sheet as 40 to 97% by weight and the amount of the fibrids as 3 to 60% by weight and partially softening and/or melting the fibrids so as to act as a binder.

Abstract: Aromatic polyamide fibers which have a crystalline structure having (1) crystal size (A) in a (110) plane of 7.5 nm, (2) crystal size (B) in a (200) plane of 8.2 nm and (3) a product A×B of 61.50 to 630.00, and exhibit a thermal linear expansion coefficient of −1.0×10−6/° C. to −7.5×10−6/° C. and thus a high dimensional stability even upon moisture-absorbing and desorbing, are useful for forming a resin-reinforcing fiber sheet, a pre-preg containing the fiber sheet, and a laminate for, for example, an electric insulating material or electric circuit board, having an excellent cutting, shaving, perforating or laser processability and capable of forming a smooth cut, shaved or perforated face.

Abstract: A wholly aromatic polyamide staple fiber fabric having excellent insulation and superior dimensional stability at a high temperature and/or a high humidity, includes 70 to 96 parts by weight of a staple fiber web made from a blend of 5 to 30% by weight of m-type wholly aromatic polyamide staple fibers and 70 to 95% by weight of p-type wholly aromatic polyamide staple fibers, and 4 to 30 parts by weight of an organic resin binder incorporated into the staple fiber web.

Abstract: A coated fiber structure having a high abrasion, flexural fatigue, and flame stardant resistance comprises a number of individual fibers having a thermal decomposition point of 230.degree. C. or more, and coating layers covering and fixed to the surfaces of the individual fibers at a surface covering percentage of 35% or more and comprising a fluorine-containing polymer in the form of individual particles provided by heat-treating the polymer on the individual fibers at a temperature of from 60.degree. C. below to 60.degree. C. above the melting point of the polymer.

Abstract: Disclosed is a chemical resistant filter material made of a fibrous structure, the fiber surface of which is coated with at least one inorganic oxide selected from oxides of silicon, aluminum and lithium, and an optional fluoropolymer resin.