Abstract: An optical device comprising a mixture of a polymer constituted mainly of aromatic vinyl monomer units and polyphenylene ether, characterized in that the average molecular weight of the polyphenylene ether is from 0.3 to 0.7 expressed in terms of the intrinsic viscosity measured in chloroform at 25.degree. C.

Abstract: There is disclosed herein an optical disk substrate comprising a copolymer produced by polymerizing 50 to 65% by weight of methyl methacrylate (a) units, 20 to 35% by weight of tricyclo[5.2.1.0.sup.2.6 ]deca-8-yl methacrylate (b) units, 5 to 25% by weight of cyclohexyl methacrylate (c) units and 1 to 5% by weight of acrylic ester (d) units.

Abstract: An optical resin material comprising at least two constituent units each having positive and negative main polarizability differences of at least 50.times.10.sup.-25 cm.sup.3 in terms of absolute values has small birefringence and good water absorbance, heat resistance and moldability.

Abstract: A process for producing oxybenzoyl copolyesters comprising 3 to 300 of repeating unit of the formula, ##STR1## wherein m and n are each 0 or 1, and W is --O--, --SO.sub.2 --, --S-- or --CO--, which comprises reacting a compound of the formula, ##STR2## wherein R.sup.1 is a hydrogen atom, a benzyl, lower alkyl or phenyl group, and Y is a hydrogen atom or a lower alkanoyl group, with a compound of the formula, ##STR3## wherein X is a halogen atom, in the presence of an aliphatic, alicyclic or aromatic hydrocarbon solvent having a boiling point of 100.degree. to 260.degree. C. under atmospheric pressure to produce bis(carboxyphenyl)phthalate, adding a compound of the formula, ##STR4## wherein W is --O--, --SO.sub.2 --, --S-- or --CO--, Z is a hydrogen atom or an alkanoyl group, and m and n are each 0 or 1, and optionally a compound of the formula, ##STR5## wherein R.sup.2 and R.sup.

Abstract: In a method producing a polycondensate by bulk polycondensation of a monomer (or a reactant mixture) which is a fluid at the polycondensation temperature, an improvement which comprises carrying out the polycondensation until substantially the whole polycondensate becomes a solid polydispersion while continually applying a shearing force sufficient for maintaining the polycondensation system in polydispersed state at a temperature of below the sintering of the produced polycondensate but sufficiently high for allowing the polycondensation to proceed substantially.

Abstract: In a process for producing aromatic polyesters by bulk condensation of polyester forming reactant the improvement which comprises using three reaction vessels, reacting a reactant compound with an acid anhydride to effect an alkanolylation reaction in the first reaction vessel to thereby prepare a monomer, removing the acids by-produced in said reaction, forming or not forming an oligomer from a part or whole of said monomer, then transferring the reaction product of the first vessel into the second reaction vessel, polycondensing said monomer and/or oligomer to produce a prepolymer in the second reaction vessel, transferring the reaction product of the second vessel into the third reaction vessel, and heating said prepolymer in said third reaction vessel, thereby obtaining an aromatic polyester of high polymerization degree.

Abstract: An aqueous dispersion of 1 - 300 parts by weight of an olefin-acrylate copolymer, said olefin having 3 to 20 carbon atoms, in 100 parts by weight of water, the dispersion optionally containing a surface active agent in a proportion of 0.1 to 20 parts by weight per 100 parts by weight of the copolymer, in which dispersion the copolymer forms substantially the dispersed phase and the water forms the continuous phase. Said dispersion can be used in paints, fiber-treating agents, paper-treating agents, leather-treating agents and adhesives, and forms a film having excellent resistance to alkali, water, weathering and heat. The above copolymer is preferably an alternating copolymer although it may be a random copolymer.