Abstract: A polycarbonate resin film of the present invention is formed from a polycarbonate resin which contains at least a constitutional unit derived from a dihydroxy compound having a bonded structure represented by the following structural formula (1) and satisfies the following expression (2) when subjected to a tensile test at a standard stretching temperature for the polycarbonate resin and at a pulling speed (strain rate) of 1,000%/min. [Chem. 1] ?CH2—O???(1) (No hydrogen atom is bonded to the oxygen atom contained in the structural formula (1).) 0.

Abstract: The invention is to provide polycarbonate resins having excellent light resistance, transparency, hue, heat resistance, thermal stability, and mechanical strength and to provide processes for efficiently and stably producing a polycarbonate resin which stably shows those performances. The invention includes: polycarbonate resins which at least contain structural units derived from a dihydroxy compound having the portion represented by the following general formula (1) as part of the structure thereof and which have specific properties; and processes for producing the polycarbonate resins. [Chem. 1] ?CH2—O???(1) (The case where the portion represented by general formula (1) is part of —CH2—O—H is excluded.

Abstract: The problem to be solved by the present invention is to provide a polycarbonate copolymer containing a plant-derived raw material, which is excellent in the mechanical strength and heat-resistant and assured of small refractive index, large Abbe number, small birefringence and excellent transparency. The present invention provides a polycarbonate copolymer containing a constitutional unit derived from a dihydroxy compound represented by the following formula (1) and a constitutional unit derived from an alicyclic dihydroxy compound, wherein the Abbe number is 50 or more and the 5% thermal reduction temperature is 340° C. or more; and a method of producing this polycarbonate copolymer by reacting a dihydroxy compound represented by the following formula (1) and an alicyclic hydroxy compound with a carbonic acid diester in the presence of a polymerization catalyst.

Abstract: A subject for the invention is to provide a polycarbonate having excellent mechanical strength, heat resistance, a low refractive index, a large Abbe number, reduced birefringence, and excellent transparency. The invention relates to a polycarbonate characterized by being obtained by subjecting one or more dihydroxy compounds including a dihydroxy compound having at least one linking group —CH2—O— in the molecule thereof to melt polycondensation with a carbonic acid diester, and by having a reduced viscosity of from 0.40 dL/g to 1.70 dL/g and a formic acid content lower than 5 ppm by weight.

Abstract: A subject for the invention relates to processes for producing a polycarbonate containing a plant-derived starting material and to molded articles thereof, the polycarbonate having excellent mechanical strength, heat resistance, a low refractive index, a large Abbe number, low birefringence, and excellent transparency. The invention relates to a process for producing a polycarbonate which includes a step in which one or more dihydroxy compounds including a dihydroxy compound having at least one linking group —CH2—O— in the molecule thereof are reacted with a carbonic acid diester in the presence of a polymerization catalyst, wherein the dihydroxy compound having at least one linking group —CH2—O— in the molecule thereof has a formic acid content lower than 20 ppm.

Abstract: The object is to provide a polycarbonate copolymer having excellent mechanical strength, good heat resistance, a low refractive index, a large Abbe number, a low berefringence and excellent transparency and containing a plant-derived raw material. Disclosed is a polycarbonate copolymer which comprises a constituent unit derived from a dihydroxy compound represented by the general formula (1) and a constituent unit derived from an alicyclic dihydroxy compound and has an Abbe number of 50 or greater and “a 5% heating weight loss temperature” (a temperature at which the 5% weight loss under heating is observed) of 340° C. or higher. Also disclosed is a process for producing the polycarbonate copolymer by reacting a dihydroxy compound represented by the general formula (1) and an alicyclic dihydroxy compound with a carbonate diester in the presence of a polymerization catalyst.

Abstract: The aim of the invention is to stably provide a polyester polymer which has excellent transparency, mechanical and electric characteristics, and extremely low optical anisotropy and excellent moldability and size stability for engineering plastics, particularly suitable for optical materials. The above-mentioned problem can be achieved by a polyester polymer, obtainable from a dicarboxylic acid compound and a dihydroxy compound, wherein the dicarboxylic acid compound comprises an alicyclic dicarboxylic acid and/or its ester-forming derivative, the dihydroxy compound comprises a compound of the general formula (1): and a content of a diethylene glycol in the polyester polymer is 6 mol % or lower.

Abstract: The aim of the invention is to stably provide a polyester polymer which has excellent transparency, mechanical and electric characteristics, and extremely low optical anisotropy and excellent moldability and size stability for engineering plastics, particularly suitable for optical materials. The above-mentioned problem can be achieved by a polyester polymer, obtainable from a dicarboxylic acid compound and a dihydroxy compound, wherein the dicarboxylic acid compound comprises an alicyclic dicarboxylic acid and/or its ester-forming derivative, the dihydroxy compound comprises a compound of the general formula (1): ; and a content of a diethylene glycol in the polyester polymer is 6 mol % or lower.

Abstract: The present invention provides a resin which is low in birefringence and superior in transparency, mechanical strength and dimension stability, and has high heat resistance and good fluidity, and which can be suitably used for optical materials. A resin composition obtained by blending a polyester polymer obtainable from a dicarboxylic acid compound and a dihydroxyl compound with a polycarbonate, wherein the dicarboxylic acid compound comprises an alicyclic dicarboxylic acid and/or an ester-forming derivative thereof, and the polyester polymer comprises fluorine dihydroxyl compounds. The present invention can provide a material which is low in birefringence and superior in transparency, mechanical strength and dimension stability, and has high heat resistance, good fluidity, and good balance between moldability and optical properties, and can provide a resin which can be suitably used for optical materials such as a camera lens, an eyeglass lens, an optical disk, an optical fiber and an optical sheet.

Abstract: A polyester polymer includes a dicarboxylic acid or its ester-forming derivative and a dihydroxy compound, in which the dicarboxylic acid contains an alicyclic dicarboxylic acid and optionally an aromatic dicarboxylic acid, and the dihydroxy compound contains a compound of formula (1): ##STR1## wherein R.sub.1 represents a C.sub.1-4 alkylene group; and R.sub.2, R.sub.3, R.sub.4 and R.sub.5 each represents a hydrogen atom, a C.sub.1-4 alkyl group, an aryl group or an aralkyl group which may be the same or different. Also, polyester moldings of disc substrates, lenses, sheets, films, tubes or fibers are produced by molding the polyester polymer. The polyester polymer has excellent transparency, excellent heat resistance, extremely low optical anisotropy and excellent moldability.

Abstract: Provided is a polyester from 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorenes as a diol component, and this novel polymer is excellent in transparency and heat resistance, has small optical anisotropy, is excellent in moldability, dimensional stability and chemical resistance and is industrially suitable for use in the fields of optical materials, fibers, films and sheets.