Abstract: A process for producing a lens comprising polymerizing bis(&bgr;-epithiopropyl)ether to form a lens.

Abstract: A composition comprising (a) 30 to 95% by weight of a compound having, in one molecule, one or more structures represented by the following formula (1): wherein R1 is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms, R2, R3 and R4 are each hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, Y is O, S, Se or Te, m is an integer of 1 to 5 and n is an integer of 0 to 5; (b) 1 to 40% by weight of a compound having at least one group selected from the group consisting of isocyanate group and isothiocyanate group in one molecule; and (c) 1 to 50% by weight of a compound having at least one mercapto group in one molecule. A resin produced by curing the composition by polymerization has an excellent impact resistance and optical properties, and is suitable as an optical material.

Abstract: An improved process for producing optical materials with minimized yellowing is described. The process is characterized by polymerizing/curing a composition for optical materials after adding a bluing agent. With the use of the bluing agent, the yellowing is minimized even when a large amount of an ultraviolet light absorber is used to improve a light resistance of the resultant optical material, thereby enabling the production of optical materials having a colorless and transparent appearance and excellent optical properties.

Abstract: A process for tinting a resin for optical materials, the resin containing sulfur, includes dipping the resin for optical materials into a liquid containing an inorganic acid and/or an organic acid and thereafter tinting the resin. Where the organic acid is included in the liquid, the organic acid is a mixture of a first compound (I) having sulfo group and a second compound (II) having phenolic hydroxyl group but not having sulfo group, with a ratio (I)/(II) of the first compound to the second compound, in an amount by weight, being 0.01 to 2.0.

Abstract: An ether compound having a specific episulfide structure and a cured resin prepared by using this ether compound.

Abstract: An improved process for producing optical materials with minimized yellowing is described. The process is characterized by polymerizing/curing a composition for optical materials after adding a bluing agent. With the use of the bluing agent, the yellowing is minimized even when a large amount of an ultraviolet light absorber is used to improve a light resistance of the resultant optical material, thereby enabling the production of optical materials having a colorless and transparent appearance and excellent optical properties.

Abstract: A composition for a resin which comprises (a) a compound having one or more structures represented by the following formula in one molecule: wherein R1 represents a hydrocarbon group having 1 to 10 carbon atoms, R2, R3 and R4 each represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, X represents S or O, and an average number of S represented by X is about 50% or more of a total number of S and O constituting the three-member ring, and (b) a compound having one or more active hydrogen atoms in one molecule and which is an alcohol having an acryloyloxy group or a methacryloyloxy group, or a mercaptoalcohol.

Abstract: A process for producing a resin used for preparing an optical material. The process comprises curing a composition comprising an ultraviolet light absorbent and an epithio compound by polymerization in the presence of a catalyst, wherein the ultraviolet light absorbent and the catalyst are in amounts, each expressed as parts by weight per 100 parts by weight of the total amount of the epithio compound, which satisfy both of the following relationships (a) and (b): (a) 0.001≦ultraviolet light absorbent≦1,000, and (b) 0.001≦catalyst≦5,000. The process prevents coloration and clouding of optical material for a lens obtained by polymerization of an epithio compound caused by addition of an ultraviolet light absorbent.

Abstract: A process for tinting a resin and a tinted optical material produced by the process. The process comprising dipping a resin into a liquid containing at least one compound selected from the group consisting of polar inorganic compounds and polar organic compounds and subsequently tinting the resin, wherein the resin is obtained by curing by polymerization of a sulfur-containing compound alone or a composition comprising the sulfur-containing compound, the sulfur-containing compound having in the molecule thereof one or more structures represented by the following formula hydrocarbon group having 1 to 10 carbon atoms, R2, R3 and R4 each represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, Y represents S or O and n represents 0 or 1.

Abstract: An acidic substance is added to a mixture containing a compound having epithio structures and a catalyst for curing the compound and the mixture is solidified. The mixture containing a compound having epithio structures and a catalyst for curing the compound can be mildly solidified for disposal.

Abstract: A composition for a resin comprising (a) a sulfur-containing compound having in one molecule one or more episulfide groups and/or epoxy groups and (b) a compound having in one molecule one or more isocyanate groups and/or thioisocyanate groups. The composition is useful as an optical material such for a plastic lens for glasses, since the composition exhibits an excellent balance between refractivity index and Abbe number and has a high impact resistance.

Abstract: A resinous composition which comprises a compound having, in one molecule, one or more structures of the formula (1) ##STR1## wherein R.sup.1 is a hydrocarbon having 1 to 10 carbon atoms; R.sup.2, R.sup.3 and R.sup.4 are each hydrogen or a hydrocarbon group having 1 to 10 carbon atoms; and X is S or O, and a ratio of S to the total of S and O constituting the three-membered ring is 50% or more on the average; and another compound having one or more SH groups in one molecule. The resinous composition can be used for an optical material having improved oxidation resistance.

Abstract: An episulfide which has an alicyclic, aromatic or heterocyclic skeleton and has two or more moieties represented by the formula ##STR1## wherein X is S or O, and S is in an amount of 50% or more, on the average, of the total of S and O constituting a three-membered ring. A cured material obtained by polymerizing this episulfide compound is a desirable optical material for various uses, particularly as a lens material for spectacles.

Abstract: An alkyl sulfide type episulfide compound represented by the following general formula (I) or (II) is herein disclosed: ##STR1## A material obtained by polymerizing/curing the above-mentioned compound is desirable as an optical material for various purposes, particularly a lens material for spectacles.