Abstract: 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.

Abstract: 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.

Abstract: In a support device to hold a tool or a workpiece, a tightening cylinder is provided at inside with an insertion hole for a substance to be held and on an outer circumference with a taper surface, a rotary cylinder is rotatably and externally fitted to outside of the tightening cylinder through a number of rollers, the rotary cylinder is rotated thereby the rotary cylinder is moved towards diameter side of the tightening cylinder and the tightening cylinder is contracted so as to tighten the substance to be held. Since a number of strain absorbing holes are provided on the inner circumferential surface of the tightening cylinder and scattered uniformly in the axial direction and in the circumferential direction, the deflection adaptability of the tightening cylinder is high and the tightening cylinder can be contracted by a relatively small force.

Abstract: 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%.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A device for attaching a tool to a machine tool is disclosed. A cylindrical hollow portion is provided in a spindle of the machine tool, and a gripper having locking elements is provided at a deep portion thereof. On the other hand, a tool is attached in advance to an installing and removing member which can be inserted into the hollow portion of the spindle. A connecting body having an engaging body is provided at the extremity of the installing and removing member. The installing and removing member to which the tool is attached in advance is inserted into the hollow portion of the spindle and the installing and removing member is rotated through a predetermined angle whereby the engaging body comes into engagement with the locking body to lock the tool to the spindle.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.