Abstract: The present invention relates to a process for the production of a polyurethane lens, which comprises the step (a) of providing a polyisocyanate compound and two or more polythiol compounds which have different reaction rates with the polyisocyanate compound and adding an alkyltin halide compound to the above polyisocyanate compound, and, after the step (a), the step (b) of mixing the polyisocyanate compound and the two or more polythiol compounds together with the alkyltin halide compound of the general formula (I) to allow them to react, and obtaining a polyurethane lens.

Abstract: A process for producing a polythiol oligomer having disulfide linkages by reacting polythiol (with the functionality of two or above) with sulfur in a molar ratio of m to (m-1) (where m is an integer of 2 to 21) in the presence of a basic catalyst, whereby the oligomers produced have a degree of oligomerization of m (wherein m is defined as above). Specifically disclosed is a process for reacting 2,5-dimercaptomethyl-1,4-dithiane (DMMD) with sulfur in a molar ratio 2:1 or 3:2 in the presence of a basic catalyst, thereby producing an oligomer represented by the below formula: ##STR1## (wherein n is an integer of up to 21). Also disclosed are optical polymers made with the oligomer and optical materials and devices made with the polymer.

Abstract: The present invention relates to a process for the production of a polyurethane lens, which comprisesthe step (a) of providing a polyisocyanate compound and two or more polythiol compounds which have different reaction rates with the polyisocyanate compound and adding an alkyltin halide compound to the above polyisocyanate compound, and, after the step (a),the step (b) of mixing the polyisocyanate compound and the two or more polythiol compounds together with the alkyltin halide compound of the general formula (I) to allow them to react, and obtaining a polyurethane lens.

Abstract: The present invention relates to a process for the production of a polyurethane lens, which comprises the step (a) of providing a polyisocyanate compound and two or more polythiol compounds which have different reaction rates with the polyisocyanate compound and adding an alkyltin halide compound to the above polyisocyanate compound, and, after the step (a), the step (b) of mixing the polyisocyanate compound and the two or more polythiol compounds together with the alkyltin halide compound of the general formula (I) to allow them to react, and obtaining a polyurethane lens.

Abstract: A polymer used for optical products wherein the polymer comprises 2,5-dimethyl-1,4-dithiane skeletons represented by formula (1): ##STR1## and 1,3,5-trimethylcyclohexane skeletons represented by formula (2): ##STR2## and a part of or all of bonds between the 2,5-dimethyl-1,4-dithiane skeleton and the 1,3,5-trimethylcyclohexane skeleton are thiourethane bonds. The polymer exhibits 1.63 or more of refractive index, 35 or more of Abbe's number and 100.degree. C. or more of second-order transition point. The polymer is prepared by polyaddition of 2,5-dimercaptomethyl-1,4-dithiane and 1,3,5-triisocyanatomethylcyclohexane.

Abstract: The anti-reflection optical element of the present invention achieves reduction of surface reflection by providing a multi-layered anti-reflection film directly or indirectly on an optical component made of a plastic. The anti-reflection optical element of the present invention uses a multi-layered anti-reflection film comprising at least one high refractive index film layer which is a film of mixed metal oxides comprising tantalum oxide, zirconium oxide and yttrium oxide deposited by evaporation process, and thereby has solved the problems of conventional anti-reflection optical elements that their optical, mechanical and chemical properties are deteriorated with the lapse of time.

Abstract: A polyurethane lens is produced by (a) adding to a monomer mixture comprising a polyisocyanate and a polythiol, a phosphoric acid ester represented by the general formula (I) ##STR1## (R.sub.1 and R.sub.2 which may be the same or different are each an alkyl group of 1-8 carbon atoms) and then (b) subjecting the monomer mixture containing the phosphoric acid ester, obtained in the step (a) to cast polymerization in a mold for plastic lens production. Said polyurethane lens has good releasability from mold, is free from color unevenness after tinting and cloudiness, and possesses high refractive index (N.sub.D) and high optical dispersion.