Abstract: A cutting insert may include a base member. The base member may include a first surface, a second surface adjacent to the first surface, and a first cutting edge located in at least a part of a first ridge line which the first surface intersects with the second surface. The base member may include a hard phase containing a titanium carbonitride, and a binding phase containing at least one of cobalt and nickel. The hard phase may include a first hard phase observed on a higher angle side, and a second hard phase observed on a lower angle side in a comparison of (422) plane peak in an X-ray diffraction analysis. A compressive residual stress of the second hard phase in the second surface may be less than a compressive residual stress of the second hard phase in the first surface.

Abstract: A cutting insert may include a base member. The base member may include a first surface, a second surface adjacent to the first surface, and a first cutting edge located in at least a part of a first ridge line which the first surface intersects with the second surface. The base member may include a hard phase containing a titanium carbonitride, and a binding phase containing at least one of cobalt and nickel. The hard phase may include a first hard phase observed on a higher angle side, and a second hard phase observed on a lower angle side in a comparison of (422) plane peak in an X-ray diffraction analysis. A compressive residual stress of the second hard phase in the second surface may be less than a compressive residual stress of the second hard phase in the first surface.

Abstract: A cutting insert may include a base member. The base member may include a first surface, a second surface adjacent to the first surface, and a first cutting edge located in at least a part of a first ridge line which the first surface intersects with the second surface. The base member may include a hard phase containing a titanium carbonitride, and a binding phase containing at least one of cobalt and nickel. The hard phase may include a first hard phase observed on a higher angle side, and a second hard phase observed on a lower angle side in a comparison of (422) plane peak in an X-ray diffraction analysis. A compressive residual stress of the second hard phase in the second surface may be less than a compressive residual stress of the second hard phase in the first surface.

Abstract: A film which is a single polymer film and has a smaller phase difference as the wavelength becomes shorter. This film is made from an olefin-based polymer which has an alicyclic group in the side chain, such as hydrogenated polystyrene, the amount of the alicyclic group in the side chain being 60 to 90 wt % based on the whole polymer, and satisfies the following expression: R(450)/R(550)<1 wherein R(450) and R(550) are phase differences on the film plane at a wavelength of 450 nm and a wavelength of 550 nm, respectively.

Abstract: The present invention relates to a hydrogenated styrene-conjugated diene-styrene copolymer having excellent toughness, heat distortion temperature, and moldability, a production process therefor, and an optical material, etc. employing the copolymer.

Abstract: An optical recording medium for recording and reproducing information utilizing the change of a physical property of a recording layer caused by the irradiation with light, which comprises a substrate, characterized in that the substrate comprises a hydrogenated styrene polymer having a content of nucleus-hydrogenated styrene units of 80 wt % or more, has a glass transition temperature of 110° C. or higher, has a light transmittance of 88% or more at 400 nm, and exhibits an absolute value of retardation of 30 nm or less at 0° and 30° from the normal direction of the plane thereof. The optical recording medium suitable for use in the high density optical recording capable of responding to a greater number of openings and the use of a light having a shorter wave length in an optical head.

Abstract: A process for producing a hydrogenation product of a ring-containing unsaturated hydrocarbon polymer, which product is low in the content of the heterogeneous catalyst used.

Abstract: A film which is a single polymer film and has a smaller phase difference as the wavelength becomes shorter.

Abstract: An optical disk substrate having excellent replication and releasability at the time of molding, little warpage and high strength. The optical disk substrate is made from a hydrogenated styrene polymer having a nuclearly hydrogenated styrene polymer unit content of 80 wt % or more and a reduced viscosity (in toluene, 0.5 dl/g, 30° C.) of 0.3 to 0.6 dl/g and has a shrinkage factor of 4.5% or less in a radial direction at the glass transition temperature of the above hydrogenated styrene polymer. The hydrogenated styrene polymer comprises 80 wt % or more of a nuclearly hydrogenated styrene polymer unit suitable for the production of this optical disk substrate and has a glass transition temperature of 130° C. or more and a relaxation spectrum at 20° C.

Abstract: Process for producing a hydrogenated &agr;-olefin-dicyclopentadiene copolymer. The process includes a step of distilling of unreacted dicyclopentadiene or tetrahydrodicyclopentadiene which is a hydrogenated product of unreacted dicyclopentadiene from a mixture containing &agr;-olefin-dicyclopentadiene copolymer or its hydrogenated product in the presence of a high-boiling hydrocarbon solvent having a boiling point of 195 to 300° C. and an ignition point of 260° C. or more. Method for melt molding the hydrogenated &agr;-olefin-dicyclopentadiene copolymer is also proposed.

Abstract: A cyclic olefin polymer having a small content of a catalyst residue, a production process for the same and use of the same as an optical material. Catalysts used for polymerization and/or hydrogenation reaction for forming the cyclic olefin polymer are decomposed efficiently by adding at least one compound selected from the group consisting of an &agr;-oxyacid and &bgr;-oxyacid having one hydroxyl group and one carboxyl group in the molecule and derivatives obtained by substituting hydroxyl group thereof by an alkoxyl group, and the decomposition products are removed by rendering them insoluble in a reaction solvent used for the polymerization and/or hydrogenation reaction and precipitating them efficiently.

Abstract: Process for producing a hydrogenated &agr;-olefin-dicyclopentadiene copolymer. The process includes a step of distilling of unreacted dicyclopentadiene or tetrahydrodicyclopentadiene which is a hydrogenated product of unreacted dicyclopentadiene from a mixture containing &agr;-olefin-dicyclopentadiene copolymer or its hydrogenated product in the presence of a high-boiling hydrocarbon solvent having a boiling point of 195 to 300° C. and an ignition point of 260° C. or more. Method for melt molding the hydrogenated &agr;-olefin-dicyclopentadiene copolymer is also proposed.

Abstract: Process for producing a hydrogenated &agr;-olefin-dicyclopentadiene copolymer. The process includes a step of distilling of unreacted dicyclopentadiene or tetrahydrodicyclopentadiene which is a hydrogenated product of unreacted dicyclopentadiene from a mixture containing &agr;-olefin-dicyclopentadiene copolymer or its hydrogenated product in the presence of a high-boiling hydrocarbon solvent having a boiling point of 195 to 300° C. and an ignition point of 260° C. or more. Method for melt molding the hydrogenated &agr;-olefin-dicyclopentadiene copolymer is also proposed.

Abstract: &agr;-olefin-cycloolefin copolymers which (1) consist essentially of 0-31% by mole of an &agr;-olefin component represented by the following formula (A) wherein R1 is a hydrogen atom or a saturated aliphatic hydrocarbon group of 1-16 carbon atoms, and 61-100% by mole of a cycloolefin component represented by the following formula (B) wherein R2 is a hydrogen atom or a saturated aliphatic hydrocarbon group of 1-16 carbon atoms, and (2) have a reduced viscosity &eegr;sp/c which is in the range of 0.1-10 dl/g as measured in a 0.5 g/dl toluene solution at 30° C., hydrogenated copolymers thereof and a process for their production.

Abstract: An optically isotropic film of an aromatic polyethersulfone, which is useful as a substrate for a liquid crystal display device, and an optically anisotropic, uniaxially oriented film of an aromatic polyethersulfone, which is useful as a phase difference plate for a liquid crystal display device. The optically isotropic film is produced by casting an aromatic polyethersulfone solution composition comprising 15 to 40 parts by weight of a solvent which contains at least 60% by weight of 1,3-dioxolane and can dissolve an aromatic polyethersulfone and 10 parts by weight of the aromatic polyethersulfone, on a substrate, and heating the cast solution composition containing a solvent to evaporate the solvent off.

Abstract: An optically isotropic film of an aromatic polyethersulfone, which is useful as a substrate for a liquid crystal display device, and an optically anisotropic, uniaxially oriented film of an aromatic polyethersulfone, which is useful as a phase difference plate for a liquid crystal display device. The optically isotropic film is produced by casting an aromatic polyethersulfone solution composition comprising 15 to 40 parts by weight of a solvent which contains at least 60% by weight of 1,3-dioxolane and can dissolve an aromatic polyethersulfone and 10 parts by weight of the aromatic polyethersulfone, on a substrate, and heating the cast solution composition containing a solvent to evaporate the solvent off.

Abstract: An acylated cellulose film having a high optical isotropy and uniformity is produced by dissolving an acylated cellulose in a solvent substantially free from water and including, as a principal component, 1,3-dioxolane in a ratio in weight of the acylated cellulose to the solvent of 10/250 to 10/15; spreading the acylated cellulose solution on a film-forming surface of a support; and drying, for example, initially drying the spread solution layer on film-forming surface so as to reduce the content of the residual solvent in the resultant film to 5 to 30% by weight; removing the resultant residual solvent-containing film from the film-forming surface; and finally drying the removed film, while allowing the film to shrink in the transversal direction thereof, at a drying temperature controlled continuously or intermittently to a level satisfying the relationship (I): (Tg'-50.degree. C.).ltoreq.T.ltoreq.(Tg'+20.degree. C.) (I), wherein T is the drying temperature (.degree.C.

Abstract: An optically isotropic film of an aromatic polyethersulfone, which is useful as a substrate for a liquid crystal display device, and an optically anisotropic, uniaxially oriented film of an aromatic polyethersulfone, which is useful as a phase difference plate for a liquid crystal display device. The optically isotropic film is produced by casting an aromatic polyethersulfone solution composition comprising 15 to 40 parts by weight of a solvent which contains at least 60% by weight of 1,3-dioxolane and can dissolve an aromatic polyethersulfone and 10 parts by weight of the aromatic polyethersulfone, on a substrate, and heating the cast solution composition containing a solvent to evaporate the solvent off.

Abstract: The present invention is to provide polycarbonate film excellent in optical properties such as high transparency and a process for producing it. The present invention relates to polycarbonate film having a specific retardation values, and a process for producing polycarbonate film by casting a dope onto a support and evaporating the solvent with heat wherein the dope is prepared by dissolving 10 parts by weight of polycarbonate resin in 30 to 150 parts by weight of the solvent mixture which contains more than 60% by weight of dioxolane.

Abstract: The present invention is to provide a polycarbonate film excellent in optical properties such as high transparency and a process for producing it. The present invention relates to a polycarbonate film having a specific retardation value, and a process for producing a polycarbonate film by casting a dope onto a support and evaporating the solvent with heat wherein the dope is prepared by dissolving 10 parts by weight of polycarbonate resin in 30 to 150 parts by weight of the solvent mixture which contains more than 60% by weight of dioxolane.