Abstract: The present invention provides a method for producing polycrystalline silicon. The method for producing polycrystalline silicon comprises the steps of (A), (B), and (C), (A) reducing a chlorosilane represented by the formula (1) with a metal at a temperature T1 to obtain a silicon compound; SiHnCl4-n??(1) ?wherein n is an integer of 0 to 3, (B) transferring the silicon compound to a zone having a temperature T2, wherein T1>T2; and (C) depositing polycrystalline silicon in the zone having a temperature T2, wherein the temperature T1 is not less than 1.29 times of a melting point (Kelvin unit) of the metal, and the temperature T2 is higher than a sublimation point or boiling point of the chloride of the metal.

Abstract: The present invention provides a method for producing polycrystalline silicon. The method for producing polycrystalline silicon comprises the steps of (A), (B), and (C), (A) reducing a chlorosilane represented by the formula (1) with a metal at a temperature Ti to obtain a silicon compound; SiHnCl4-n??(1) wherein n is an integer of 0 to 3, (B) transferring the silicon compound to a zone having a temperature T2, wherein T1>T2; and (C) depositing polycrystalline silicon in the zone having a temperature T2, wherein the temperature T1 is not less than 1.29 times of a melting point (Kelvin unit) of the metal, and the temperature T2 is higher than a sublimation point or boiling point of the chloride of the metal.

Abstract: The present invention provides a method for producing high purity silicon. The method for producing high purity silicon comprises a step of reducing halogenated silicon represented by the following formula (1) with aluminum, wherein the aluminum used as a reductant has a purity of not less than 99.9% by weight, SiHnX4-n??(1) wherein n is an integer of 0 to 3, X is at least one halogen selected from the group consisting of F, Cl, Br and I; and the purity of the aluminum is the balance obtained by deducting the total % by weight of iron, copper, gallium, titanium, nickel, sodium, magnesium and zinc contained in the aluminum from 100% by weight.

Abstract: A fluororesin sheet is disclosed which comprises an aromatic polyamide pulp and a fluororesin as an essential component, the tensile strength of the fluororesin sheet being not less than about 250 kg/cm.sup.2. A process for producing this fluororesin sheet comprises dispersing the aromatic polyamide pulp and the fluororesin powder in water, adding a coagulating agent which destabilizes the dispersing of the fluororesin powder to the dispersion to deposit the fluororesin powder on the surface of the aromatic polyamide pulp, paper-making, followed by drying to obtain a sheet article, and compressing the sheet article using a roller, followed by heating.

Abstract: The aromatic polyamide pulp obtained by the process of this invention is good in dispersibility in water and good in opening property, and excellent in dispersibility of inorganic filler and wettability with and adhesion to a matrix resin such as phenol resin. Hence, an impregnated paper and molded article excellent in homogeneity and mechanical strength can be produced. Also, in the case of friction materials free from paper-making step, the filler-retention of pulp in the production process is good and such a result that the filler-dispersibility and mechanical strength of molded article are excellent is obtained, and the pulp can be utilized particularly effectively in uses as asbestos-substitutes.