Toa Nenryo Kogyo Kabushiki Kaisha

Tonen Corporation

Mitsubishi Gas Chemical Company, Inc.

Nippon Paper Industries Co., Ltd.

Toa Nenryo Kogyo, K. K.

Tsutomu Naito

Takayuki Izumi

Kikuji Komine

Takashi Hino

Takashi Onodera

Tomio Nomura

Kazuyuki Murakami

Masuo Shinya

Fumis Ohashi

Tomoo Nakamura

Hiroyuki Kuroda

Fumio Ohashi

Kuniaki Maejima

Hiroshi Toshima

Genshiro Nishimura

Masaru Miura

Hisao Tanaka

Seikoh Igarashi

Keiji Monbetsu

Seiko Igarashi

Hisao Kato

Masaru Kishida

Tomohiro Banda

Eiki Tsushima

Shigeki Yamagata

The present invention provides silicic acid hydrate having a large pore volume and tiny particle diameters, and a process for preparing it. There is disclosed silicic acid hydrate obtained by neutralizing an aqueous solution of sodium silicate with a mineral acid, which has particle properties represented by an oil absorption of 250 to 350 ml/100 g, a total pore volume of 4.0 to 6.0 cc/g, an average pore radius of 200 to 400 .ANG., and an average pore diameter of 3.0 to 15 .mu.m by the laser method, or 2.0 to 4.0 .mu.m by the coulter method, or 0.5 to 3.5 .mu.m by the centrifugal precipitation method.

Process for preparing silicic acid hydrate

An optically anisotropic pitch, which is suited for manufacturing particularly high compressive strength carbon fibers in a stable fashion, with satisfactory productivity and continuously, and also a method of manufacturing high compressive strength carbon fibers using the optically anisotropic pitch. The optically anisotropic pitch for manufacturing high compressive strength carbon fibers is composed of a benzene soluble component (BS) and a benzene insoluble component (BI) and has a Q value (i.e., weight-average molecular weight divided by number-average molecular weight) of 1.6 or below, a number-average molecular weight ratio of the benzene soluble component to the benzene insoluble component of 2.5 or below, an aromatic carbon fraction factor (fa) of 0.8 or below, a C/H atomic ratio of 1.85 or below and an optically anisotropic phase of 90% or more.

Optically anisotropic pitch for manufacturing high compressive strength

The pitch based carbon fiber has a uniform crystal structure in which substantially all crystal fibriles constituting the fiber have the thickness ranging from 30 to 200% of the average thickness Lav. Uniform stress distribution over uniform crystal fibriles can be obtained. This permits suppresion of non-linearity of the compressive modulus of elasticity of carbon fiber to greatly improve the compressive strength thereof. Typically, a compressive strength of 100 to 170 kg/mm.sup.2 can be obtained with a tensile modulus of elasticity of 50 ton/mm.sup.2. Such carbon fiber can be obtained by securing uniformity of molecular weight distribution of the liquid crystal pitch and also uniformity of the orientation of the liquid crystal constituent molecules by the application of multi-stage high shear spinning.

High compressive strength pitch based carbon fiber

A high strength, high modulus pitch-based carbon fiber has a crystalline structure in which the presence of the (112) cross-lattice line and the resolution of the diffraction band into the (100) and (101) diffraction lines, which indicate the three-dimensional order of the crystallite of the fiber, are not recognized, and in which the orientation angle (.phi.) of X-ray structural parameter is not greater than 12.degree. and the stack height (Lc) ranges between 80 and 180 .ANG.. The carbon fiber also has a single-fiber diameter of 5 to 12 .mu.m, tensile strength not lower than 3.0 GPa, tensile elastic modulus not smaller than 500 GPa and elongation not smaller than 0.5%.

High strength, high modulus pitch-based carbon fiber

A process for producing carbon fiber or graphite fiber is provided. The process comprises spinning a carbonaceous pitch, doubling spun pitch fiber bundles, adding a heat resistant doubling treatment oil, passing the fiber bundles continuously and linearly through an oxygen rich gas, infusibilizing at a temperature of 350.degree. C. or less, then carbonizing or graphitizing infusibilized fiber bundles.

Process for producing carbon fiber and graphite fiber

Extremely high modulus carbon fibers can be produced by carbonization at a substantially lower temperature, for example, at about 2500.degree. C. This is made possible by selectively stabilizing only an outer surface layer portion of a carbonaceous pitch-based fiber comprised mainly of optically anisotropic components, while retaining the inner portion of the fiber in a non-stabilized state and without damage to the crystallinity thereof.

High modulus pitch-based carbon fiber and method for preparing same

In a process for producing an optically anisotropic carbonaceous pitch having a low softening point for the production of carbon material starting oil to be used is a tar-like substance which is a mixture of compounds not substantially containing chloroform insolubles but containing components having a boiling point of 540.degree. C. or more as principal components and consisting principally of carbon and hydrogen. The tar-like substance has a content of n-heptane insolubles of up to 1 wt % and contains an aromatic oil fraction and a resin fraction as the principal components of n-heptane soluble components. The aromatic carbon fraction, fa, is at least 0.7, the number-average molecular weight is up to 1,000 and the maximum molecular weight is up to 2,000 for each of the aromatic oil and resin fractions.

Optically anisotropic carbonaceous pitch

In a process for producing an optically anisotropic carbonaceous pitch having a low softening point for the production of carbon material a starting oil to be used is a tar-like substance which is a mixture of compounds not substantially containing chloroform insolubles but containing components having a boiling point of 540.degree. C. or more as principal components and consisting principally of carbon and hydrogen. The tar-like substance has a content of n-heptane insolubles of up to 1 wt % and contains an aromatic oil fraction and a resin fraction as the principal components of n-heptane soluble components. The aromatic carbon fraction, fa, is at least 0.7, the number-average molecular weight is up to 1,000 and the maximum molecular weight is up to 2,000 for each of the aromatic oil and resin fractions.

Process for producing optically anisotropic carbonaceous pitch

A composition for an optically anisotropic carbonaceous pitch suitable for the production of a carbon material having a high tensile strength and a high modulus of elasticity. The composition comprises about 2 to 20 percent by weight of a first, n-heptane-soluble component, about 15 to 45 percent by weight of an n-heptane-insoluble and benzene-soluble, second component and the balance of the composition including benzene-insoluble components. The composition has a volume ratio of an optically anisotropic phase of at least about 90% and a softening point of up to about 320.degree. C.

Optically antisotropic carbonaceous pitch

A substantially uniform mesophase pitch is prepared by treating a mesophase forming pitch material at elevated temperatures above about 380.degree. C. to produce a mixture of mesophase and non-mesophase pitch containing about 20% to about 80% mesophase. The mixture is then maintained at a temperature below about 400.degree. C. for a time sufficient to allow the mesophase to coalesce and settle as a lower separable layer. A mesophase pitch so produced may contain from 90 to 100% mesophase with a softening point of less than 320.degree. C.

Process for producing mesophase pitch

A process for producing optically anisotropic pitch containing 80% or more of an anisotropic phase. A starting material is pyrolytically polycondensed. Afterward, the material is maintained at a temperature of between 350.degree. and 400.degree. C. to precipitate a portion of the material rich in the anisotropic phase having a high specific gravity. This portion is separated and further heat treated.

Process for producing a homogeneous low softening point, optically

A homogeneous, optically anisotropic pitch used for the production of carbon materials is prepared from a starting oil comprising a substantially chloroform-insoluble matter-free oily or tarry substance. The starting oil is subjected to thermal cracking and polycondensation to form approximately 20-80% of optically anisotropic phase pitch.

An improved dewaxing aid for solvent dewaxing process comprising a mixture of (A) an .alpha.-olefin polymer having an average molecular weight of from about 10,000 to 1,000,000 and a wide molecular weight distribution exceeding the range of from about 10,000 to 1,000,000 but falling within the range of from about 2,000 to 3,000,000 wherein the .alpha.-olefin polymer is a homopolymer made up of a C.sub.10 to C.sub.25 alpha-olefin monomer or is a copolymer made up of a monomer mixture comprising more than 50 wt. % of at least 2 C.sub.10 to C.sub.25 alpha-olefin monomers and a melt index greater than 1.8 g/10 min. and (B) an olefin vinyl acetate copolymer having a vinyl acetate content of from about 15 to 40 wt. % and an average molecular weight of from about 50,000 to 1,000,000 and a melt index greater than 2 g/10 min. The .alpha.-olefin polymer having a high molecular weight and wide molecular weight distribution, when combined with the olefin-vinyl acetate copolymer, synergistically improves the efficiency of wax separation.

Solvent dewaxing waxy hydrocarbons using an alpha olefin polymer-olefin

Solvent dewaxing waxy hydrocarbons using an .alpha.-olefin

An improved dewaxing aid for solvent dewaxing process comprising a mixture of (A) an .alpha.-olefin polymer having an average molecular weight of from about 10,000 to 1,000,000 and a wide molecular weight distribution exceeding the range of from about 10,000 to 1,000,000 but falling within the range of from about 2,000 to 3,000,000 and (B) an olefin-vinyl acetate copolymer having a vinyl acetate content of from about 15 to 40 wt.% and an average molecular weight of from about 50,000 to 1,000,000. The .alpha.-olefin polymer having a high molecular weight and wide molecular weight distribution, when combined with the olefin-vinyl acetate copolymer, synergistically improves the efficiency of wax separation.

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Saitama, Japan

Tsutomu Naito