Abstract: A shaped wholly aromatic polyamide resin composition article having an excellent mechanical strength, stain-proof property and antistatic property, and comprising a wholly aromatic polyamide resin matrix and a dispersoid comprising polytetrafluoroethylene resin particles in the form of fine networks of fibrils and, optionally, additional inorganic particles, dispersed in the matrix, is produced by mixing an aqueous dispersion of PTFE particles having an average size of 0.3 to 3 .mu.m in an amount of 0.01% to 10% based on the total weight of the shaped article, with wholly aromatic polyamide particles having a melting point of at least 50.degree. C. higher than that of PTFE and composed of porous secondary particles having an average size of 30 to 200 .mu.m and consisting of primary particles having an average size of 0.1 to 2.0 .mu.

Abstract: A brush structure comprising a plurality of striated flexible synthetic polymer sheets provided with a plurality of striae and ridges formed alternately on one or two faces of the sheet and extending in parallel to each other and to the longitudinal axis of the sheet, the striated sheets being bonded at longitudinal one end portions thereof to one another to thereby form a block or bundle of the striated sheet.

Abstract: A stretchable wholly aromatic polyamide fiber which (A) is composed of a wholly aromatic polyamide containing at least 85 mole %, based on the entire recurring units, of m-phenylene isophthalamide units as a main component, (B) does not substantially contain an aprotic polar solvent, (C) has an average denier size of 50 to 50,000, (D) when stretched to two times at the glass transition temperature of the wholly aromatic polyamide, has a maximum heat shrinkage under a fixed load of at least 30%.A stretched wholly aromatic polyamide fiber which has the same properties with (A), (B) and (C), and (D) has a maximum heat shrinkage under a fixed load of at least 20% and (E) is substantially amorphous.The present invention provides a stretchable and stretched wholly aromatic polyamide composite fiber containing inorganic pieces and processes for preparing the above fibers.

Abstract: An assembly of fibers composed of at least two dissimilar fiber-forming polymers, characterized by the fact that(1) it consists of numerous fibers,(2) at least 90% of said fibers have a non-circular cross-sectional shape,(3) the cross-sections of at least 50% of said fibers differ from each other in at least one of shape and size, and(4) at least 50% of said fibers each have in their cross-section taken at right angles to the fiber axis at least two side-by-side coalesced blocks of at least two dissimilar fiber-forming polymer phases with at least a part thereof being exposed to the peripheral surface of the fiber, at least one of the number, shape and size of the blocks varying from fiber to fiber.

Abstract: Pneumatic cellular aromatic polyamide articles characterized by(a) being articles prepared substantially from aromatic polyamide.(b) said articles having numerous bubbles at the void ratio in the range of 10 to 95%,(c) said bubbles being substantially enclosed in said articles, and(d) said articles having an average thickness in the range of 0.2 to 10 mm on the cross section made by cutting them at right angles to the longest axis.The present invention provides also a process for the preparation thereof. According to the present invention, there are suitably provided pneumatic cellular aromatic polyamide article having a high strength and a wide range of void ratio, comparatively heavy thickness, excellent heat resistance and thermal insulation.

Abstract: A process and apparatus for producing a fibrous assembly. At least one fiber-forming polymer is extruded through a spinneret having numerous small openings. The process uses a die equipped with a spinneret having numerous closely spaced small openings and an opening ratio (.alpha.) of at least 30%. At least one fiber-forming polymer in the form of a shaped mass having a specified compression resistance is continuously stuffed into said die. Said shaped mass has a shape such that it measures more in one direction than in another. There is passed through the spinneret an electric current sufficient to give said fiber-forming polymer Joule heat required for cutting said polymer by partitioning members defining the numerous small openings of the spinneret. The cut fiber-forming polymer is taken up as fine streams.The present invention provides ultrathick aromatic polyamide fibers having an average cross-sectional area of about 0.01 mm.sup.2 to about 5 mm.sup.

Abstract: Pneumatic cellular aromatic polyamide articles characterized by(a) being articles prepared substantially from aromatic polyamide.(b) said articles having numerous bubbles at the void ratio in the range of 10 to 95%,(c) said bubbles being substantially enclosed in said articles, and(d) said articles having an average thickness in the range of 0.2 to 10 mm on the cross section made by cutting them at right angles to the longest axis.The present invention provides also a process for the preparation thereof. According to the present invention, there are suitably provided pneumatic cellular aromatic polyamide articles having a high strength and a wide range of void ratio, comparatively heavy thickness, excellent heat resistance and thermal insulation.

Abstract: A novel filament composed of at least one thermoplastic synthetic polymer, said filament being characterized by having (1) an irregular variation in the size of its cross section along its longitudinal direction, and (2) a coefficient of intrafilament cross-sectional area variation [CV(F)] of 0.05 to 1.0; and a novel bundle of said filament.

Abstract: An assembly of fibers composed of at least two dissimilar fiber-forming polymers, characterized by the fact that(1) it consists of numerous fibers,(2) at least 90% of said fibers have a non-circular cross-sectional shape,(3) the cross sections of at least 50% of said fibers differ from each other in at least one of shape and size, and(4) at least 50% of said fibers each have in their cross section taken at right angles to the fiber axis at least two side-by-side coalesced blocks of at least two dissimilar fiber-forming polymer phases with at least a part thereof being exposed to the peripheral surface of the fiber, at least one of the number, shape and size of the blocks varying from fiber to fiber.

Abstract: The present invention provides a process for producing a fibrous assembly, which comprises extruding a melt of a fiber-forming polymer through a mesh spinneret, said spinneret including many closely arranged small openings and having an opening ratio (.alpha.), represented by the following formula, of at least about 10% ##EQU1## V.sub.a is the total apparent volume of the spinneret which is taken within a unit area of its mesh portion, and V.sub.

Abstract: A novel filament composed of at least one thermoplastic synthetic polymer, said filament being characterized by having (1) an irregular variation in the size of its cross section along its longitudinal direction, and (2) a coefficient of intrafilament cross-sectional area variation [CV(F)] of 0.05 to 1.0; and a novel bundle of said filament.

Abstract: A composite sheet structure comprising (A) a nonwoven web composed of (a) continuous filaments of a synthetic resin and (B) a net-like web having intersecting points and being composed of (b) continuous net strands of a mixture consisting of at least two thermoplastic synthetic resins having different melting points, said web (A) and said web (B) being bonded to each other by heating; characterized in that (i) said web (A) has a basis weight of about 2 to about 30 g/m.sup.2, (ii) said web (B) has a basis weight of about 1 to 10 g/m.sup.2, an average net strand diameter of about 1 to about 100 microns, and an average mesh length of up to about 5 mm, and said net strands (b) are composed of at least two resins having melting points differing from each other by at least about 20.degree. C., of which a resin having the lowest melting point has a melting point at least about 20.degree. C.

Abstract: A fibrous assembly of many fibers, the individual constituent fibers being interconnected at random in a spaced-apart relationship so that when spread in a direction at right angles to the longitudinal axes of the fibers, said assembly can form a continuous integral reticulated structure; said individual fibers having asymmetrical irregularly-shaped cross sections of substantially different profiles and sizes from one another when said assembly is cut at right angles to the longitudinal axes of the fibers at an arbitrary point therealong; at least 40% of the entire cross-sectional area of each fiber consisting of at least two different polymer phases which are coalesced side-by-side as at least two irregular blocks; and each of the individual fibers of said assembly having a non-uniform cross-sectional shape along its longitudinal axis; fibrous structures prepared from a plurality of such fibrous assemblies; and a process for producing such fibrous assembly.

Abstract: A liner sheet for a magnetic tape cartridge, said sheet being a fibrous sheet containing thermoplastic synthetic fibers with at least those fibers which are in its surface layer being bonded as a result of heat melting, said fibrous sheet having (1) an apparent specific gravity 0.55 to 0.85 time the specific gravity of the polymer constituting the fibers, (2) air permeability expressed by a pressure drop of not more than 200 cm Aq/mm when air is caused to flow at a speed of 10 cm/sec in a direction perpendicular to the surface of the sheet and (3) a thickness of 50 to 300 microns, and said fibrous sheet containing in its structure a lubricant and an antistatic agent dispersed therein.