Abstract: A separator for electricity storage devices which comprises: a base comprising a porous film; and a thermoplastic polymer arranged on at least one surface of the base. The thermoplastic polymer has a dispersion (?2), defined by the following numerical equation using the areas (Si) of Voronoi polygons obtained by Voronoi tessellation, of 0.01-0.7. (In the equation, Si is the measured area of each Voronoi polygon, m is an average of the measured areas of the Voronoi polygons, and n is the total number of the Voronoi polygons).

Abstract: A separator for electricity storage devices which comprises: a base comprising a porous film; and a thermoplastic polymer arranged on at least one surface of the base. The thermoplastic polymer has a dispersion (?2), defined by the following numerical equation using the areas (Si) of Voronoi polygons obtained by Voronoi tessellation, of 0.01-0.7. (In the equation, Si is the measured area of each Voronoi polygon, m is an average of the measured areas of the Voronoi polygons, and n is the total number of the Voronoi polygons.

Abstract: Disclosed is a resin composition comprising (.alpha.) at least one polymer selected from the group consisting of a non-modified cyclic monomer unit-containing polymer and a modified cyclic monomer unit-containing polymer having a number average molecular weight of from 10,000 to 5,000,000, wherein the cyclic monomer unit is derived from a cyclic conjugated diene, and (.beta.) at least one polymer other than the polymer (.alpha.), and wherein the polymer (.alpha.) is present in an amount of at least 1% by weight, based on the total weight of the polymers (.alpha.) and (.beta.). The molecular structure of the polymer (.alpha.) which is contained in the novel resin composition of the present invention and which is selected from a non-modified cyclic monomer unit-containing polymer and a modified cyclic monomer unit-containing polymer, wherein the cyclic monomer unit is derived from a cyclic conjugated diene, can be controlled with large freedom. Therefore by combining the polymer (.alpha.) with a polymer (.beta.

Abstract: Disclosed is a polymer containing a modified cyclic monomer unit, comprising a polymer chain represented by the following formula (I): ##STR1## wherein A to F are monomer units constituting a main chain of the polymer chain, in which monomer units A to F are arranged in any order, and l to q are, respectively, weight percentages of monomer units A to F, based on the total weight of monomer units A to F; A is selected from cyclic olefin monomer units, B is selected from cyclic conjugated diene monomer units, and C to F are monomer units copolymerizable with monomer units A and B, wherein each of S to X, which are modifying groups, is a functional group or an organic compound residue containing the functional group, with the functional group containing at least one member selected from oxygen, nitrogen, sulfur, silicon, phosphorus and halogen; and wherein s to x are, respectively, weight percentages of modifying groups S to X, based on the weight of the polymer, and wherein the polymer has a number average mole

Abstract: The present invention provides a novel polymeric composite material which contains at least two polymers selected from the group consisting of a polymer having a cyclic conjugated diene monomer unit and/or a cyclic olefin monomer unit and a modified polymer thereof. The novel composite material of the present invention can exhibit excellent thermal and mechanical properties while maintaining properties as a mono material so that it is widely applicable to major uses for polymer materials.

Abstract: The methacrylic copolymer of the present invention is a novel copolymer having low moisture absorption properties which comprises specific proportions of methyl methacrylate units and tert-butylcyclohexyl methacrylate units, optionally with specific ethylenically unsaturated compound units copolymerizable with the above-mentioned monomer units. The copolymer of the present invention is excellent not only in colorlessness, transparency, moldability, low double refraction and heat stability but also in low moisture absorption properties and heat resistance and, therefore, is suitable for use as a material for shaped articles, such as an optical element substrate and a light transmissible extruded plate, and can particularly advantageously be used for applications, such as an optical disc substrate.

Abstract: Optical materials having well balanced properties such as high heat resistance, low hygroscopicity and low double refractivity. The optical materials are derived from a low hygroscopic, random copolymer comprising units of methacrylic acid and ester derivatives, and units of a six-membered ring acid anhydride.