Abstract: There is provided a film comprising a layered silicate cation-exchanged with an organic cation and a polyester or polycarbonate. The organic cation is represented by the following formula (I): (R)n-L+??(I) wherein R is a group represented by the following formula (I-1): wherein R1 is a divalent hydrocarbon group having 5 to 20 carbon atoms, and R2 is a divalent hydrocarbon group having 1 to 20 carbon atoms, an alkyl group, an aryl group or an aralkyl group, L+ is an ammonium ion, a phosphonium ion or a hetero aromatic ion, and n is an integer of 1 to 4, with the proviso that when L+ is an ammonium ion or a phosphonium ion, n is 4 and four Rs may be the same or different. This film has the layered silicate highly dispersed therein and is excellent in various properties such as mechanical properties and dimensional stability.

Abstract: There is provided a film comprising a layered silicate cation-exchanged with an organic cation and a polyester or polycarbonate. The organic cation is represented by the following formula (I): (R)n-L+??(I) wherein R is a group represented by the following formula (I-1): wherein R1 is a divalent hydrocarbon group having 5 to 20 carbon atoms, and R2 is a divalent hydrocarbon group having 1 to 20 carbon atoms, an alkyl group, an aryl group or an aralkyl group, L+ is an ammonium ion, a phosphonium ion or a hetero aromatic ion, and n is an integer of 1 to 4, with the proviso that when L+ is an ammonium ion or a phosphonium ion, n is 4 and four Rs may be the same or different. This film has the layered silicate highly dispersed therein and is excellent in various properties such as mechanical properties and dimensional stability.

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: 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 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.