Abstract: A separable tow of elongated polymeric filaments comprises a plurality of distinct sub-tows lightly and individually and separably joined, as by light crimping together along their edges or, if uncrimped, joined by presence of moisture, and capable of being packed into a container and later removed and separated. The filaments are preferably acrylic and have a total fineness of about 300,00-1,500,000 denier and the sub-tows each of which has a total fineness of about 50,000-250,000 denier, with a filament fineness of about 1-2 denier, and each sub-tow has a degree of entanglement of about 10-40 m−1 as measured by the hook drop test. The separable tow is made of a plurality of sub-tows, after separately drawing the sub-tows and subsequently removably joining the sub-tows into a single tow.

Abstract: Applying a sizing agent as a water dispersed sizing agent to a continuous carbon fiber bundle consisting of 20,000 to 150,000 filaments, controlling the packing density in a range of 5,000 to 20,000 D/mm, cutting the carbon fiber bundle in a wet state of 10 to 35 wt % in solution content at the time of cutting, and drying with vibration at a solution content of 15 to 45 wt % before drying.

Abstract: A separable tow of elongated polymeric filaments comprises a plurality of distinct sub-tows lightly and individually and separably joined, as by light crimping together along their edges or, if uncrimped, joined by presence of moisture, and capable of being packed into a container and later removed and separated. The filaments are preferably acrylic and have a total fineness of about 300,00-1,500,000 denier and the sub-tows each of which has a total fineness of about 50,000-250,000 denier, with a filament fineness of about 1-2 denier, and each sub-tow has a degree of entanglement of about 10-40 m−1 as measured by the hook drop test.

Abstract: A separable tow of elongated polymeric filaments comprises a plurality of distinct sub-tows lightly and individually and separably joined, as by light crimping together along their edges or, if uncrimped, joined by presence of moisture, and capable of being packed into a container and later removed and separated. The filaments are preferably acrylic and have a total fineness of about 300,00-1,500,000 denier and the sub-tows each of which has a total fineness of about 50,000-250,000 denier, with a filament fineness of about 1-2 denier, and each sub-tow has a degree of entanglement of about 10-40 m−1 as measured by the hook drop test. The separable tow is made of a plurality of sub-tows, after separately drawing the sub-tows and subsequently removably joining the sub-tows into a single tow.

Abstract: A bundle of short chopped carbon fibers impregnated with a sizing agent, the short fiber bundle having an average weight per unit length of 1.7 to 4 mg/mm in the fiber length direction and a coefficient of variation of 30 to 60% in the distribution of weight per unit length in the fiber length direction.

Abstract: An amorphous carbon material, especially for an electrode of a lithium ion secondary battery, is characterized by an interlayer spacing d(002), obtained from the X-ray diffraction line assigned to the (002) plane of the carbon, of 0.345 nm to 0.365 nm, a ratio (Ps) os the number of carbon atoms involved in the layer structure to the total number of carbon atoms of from 0.54 to 0.85, and a ratio of the total nitrogen:total carbon atoms in the amorphous carbon of 0.005:1 to 0.055:1. The amorphous carbon material is prepared by applying a heat treatment to an amorphous carbon under under vacuum or inert gas atmosphere for at least 30 minutes to provide the desired crystalline structure. The carbon material may take the form of carbon fiber material, especially short carbon fibers obtained by pulverizing larger carbon fibers. A lithium ion secondary battery containing an electrode comprising such an amorphous carbon material has a large discharge capacity and high charge-discharge cycle characteristics.

Abstract: The present invention relates to an electrode for batteries comprising carbon fibers having a crystallite thickness determined by X-ray diffraction method of not less than 1.3 nm and not more than 1.7 nm. The present invention also relates to a process for producing an electrode for batteries employing carbon fibers, comprising baking the carbon fibers at a temperature of not lower than 900.degree. C. and not higher than 1330.degree. C. The present invention enabled to provide a secondary battery which exploits the properties of carbon fibers and which has a high discharging capacity.

Abstract: A graphite fiber having an elastic modulus E of 340-680 GPa, a microvoid radius of not larger than 20 .ANG. and a crystal size L.sub.c (.ANG.) satisfying the following formula:L.sub.c.sup.3 .ltoreq.0.918.times.10.sup.3 E-3.times.10.sup.5is valuable for a composite material having an improved compression strength. The graphite fiber is made preferably by oxidizing an acrylonitrile polymer precursor containing 0.05-8 wt. % of comonomer units and having an iodine adsorption amount of not larger than 3 wt. % and an orientation degree of at least 85%, at 200.degree.-300.degree. C. in an oxidative atmosphere under tension to obtain an oxidized fiber having a water adsorption of not larger than 7 wt. % and an orientation degree of at least 78%, followed by carbonization and graphitization of the oxidized fiber under tension.

Abstract: A heat-shrinkable sheet made of a foamed thermoplastic resin having a number of cells and which is adapted to cover a fragile container such as a glass bottle, is heat-shrunk so that said sheet can stick to the container. The cells of the sheet are burst, i.e., opened or collapsed, so that the surface of the sheet which contacts the surface of a container is formed in a convexo-concave surface, which facilitates the entry of boiling water or cooling water between the sheet and the surface of the container when the sheet is adhered to the container.

Abstract: An improved electric resistance heating element made of a carbon material, provided around its surface with a layer essentially comprising carbon fiber, and an improved electric resistance heating furnace using the heating element.