Abstract: There are herein disclosed a transparent optical material containing at least one selenium atom, a plastic lens comprising the transparent optical material, and methods for preparing them.

Abstract: A polymerizable composition according to the present invention is characterized by that it comprises a compound (a) having at least one structure represented by the following formula (1): wherein R1 is a divalent hydrocarbon group having 1 to 10 carbon atoms, R2, R3 and R4 each independently represents a hydrocarbon group having 1 to 10 carbon atoms or a hydrogen atom; X stands for an S or O atom and the average number of S atom is at least 50% based on the total number of S and O atoms which consist of the three membered ring; and X′ is —S— or —O—, at least two compounds (b) having a tertiary amino group substituted with aliphatic and/or aromatic group(s), which are each different in catalytic activity as a polymerization catalyst, with the proviso that the ratio of the total of the tertiary amino groups in the at least two compounds (b) to the episulfide groups in compound (a) is in the range of 0.0001 to 0.

Abstract: An optical resin prepared by curing a polymerizable composition comprising a (thio)epoxy compound having at least one intramolecular disulfide bond exhibits a considerably high refractive index while maintaining good optical properties and a high Abbe number. In addition, the above polymerizable composition to which is added primary and/or secondary amines as an yellowing inhibitor in a proportion of 0.001 to 0.5 of the total molar number of NH2 and NH groups in the amines to the total molar number of thioepoxy and epoxy groups in the (thio)epoxy compound having at least one intramolecular disulfide bond, can provide a transparent resin in which yellowing and reduction in heat resistance associated therewith are adequately prevented while maintaining a high refractive index.

Abstract: A transparent optical material containing at least one selenium atom, a plastic lens comprising the transparent optical material, and methods for preparing them. In addition, there are also disclosed novel selenium-containing compounds represented by the following formulae (1), (2) and (4) which are useful for the transparent optical material and the plastic lens: wherein symbols are as defined in the specification.

Abstract: An optical resin prepared by curing a polymerizable composition comprising a (thio)epoxy compound having at least one intramolecular disulfide bond exhibits a considerably high refractive index while maintaining good optical properties and a high Abbe number. In addition, the above polymerizable composition to which is added primary and/or secondary amines as an yellowing inhibitor in a proportion of 0.001 to 0.5 of the total molar number of NH2 and NH groups in the amines to the total molar number of thioepoxy and epoxy groups in the (thio)epoxy compound having at least one intramolecular disulfide bond, can provide a transparent resin in which yellowing and reduction in heat resistance associated therewith are adequately prevented while maintaining a high refractive index.

Abstract: An optical resin prepared by curing a polymerizable composition comprising a (thio)epoxy compound having at least one intramolecular disulfide bond exhibits a considerably high refractive index while maintaining good optical properties and a high Abbe number. In addition, the above polymerizable composition to which is added primary and/or secondary amines as an yellowing inhibitor in a proportion of 0.001 to 0.5 of the total molar number of NH2 and NH groups in the amines to the total molar number of thioepoxy and epoxy groups in the (thio)epoxy compound having at least one intramolecular disulfide bond, can provide a transparent resin in which yellowing and reduction in heat resistance associated therewith are adequately prevented while maintaining a high refractive index.

Abstract: An optical resin prepared by curing a polymerizable composition comprising a (thio)epoxy compound having at least one intramolecular disulfide bond exhibits a considerably high refractive index while maintaining good optical properties and a high Abbe number. In addition, the above polymerizable composition to which is added primary and/or secondary amines as an yellowing inhibitor in a proportion of 0.001 to 0.5 of the total molar number of NH2 and NH groups in the amines to the total molar number of thioepoxy and epoxy groups in the (thio)epoxy compound having at least one intramolecular disulfide bond, can provide a transparent resin in which yellowing and reduction in heat resistance associated therewith are adequately prevented while maintaining a high refractive index.

Abstract: A transparent optical material containing at least one selenium atom, a plastic lens comprising the transparent optical material, and methods for preparing them. In addition, there are also disclosed novel selenium-containing compounds represented by the following formulae (1), (2) and (4) which are useful for the transparent optical material and the plastic lens: ##STR1## wherein symbols are as defined in the specification.

Abstract: A polythiol having four or more functional groups, a process for producing the polythiol comprising reacting thiourea with a specific compound, a sulfur-containing urethane-based resin prepared from the polythiol and a lens made of the resin. The resin has a high refractive index, and low dispersion of refractive index, is lightweight, colorless and transparent, has no optical distortion, and has excellent characteristics in weatherability, dye-affinity, heat resistance, impact resistance and machinability.

Abstract: A composition for polysulfide-based resin comprising a polythiol having 4 or more functional groups and a compound having a reactive unsaturated bond(s) and/or b epoxy group(s) and/or c iso(thio)cyanato group(s) in one molecule (however, a+b+c.gtoreq.2, and a and b are not simultaneously 0). A polysulfide-based resin obtained by curing the composition, an optical material comprising the resin, a lens consisting of the optical material and a method for producing the polysulfide-based resin are also set forth.

Abstract: A novel polythiol having four or more functional groups, a process for producing the polythiol comprising reacting thiourea with a specific compound, a sulfur-containing urethane-based resin prepared from the polythiol and a lens made of the resin. The resin has a high refractive index, and low dispersion of refractive index, is lightweight, colorless and transparent, has no optical distortion, and has excellent characteristics in weatherability, dye-affinity, heat resistance, impact resistance and machinability.

Abstract: One aspect of the present invention relates to a process for preparing plastic lenses having a high-refractive index comprising forming a mixture containing one or more polyisocyanate compounds; one or more active hydrogen compounds selected from the group consisting of a polyol compound having no sulfur atom, a polyol compound having at least one sulfur atom, and a polythiol compound having at least one sulfur atom in addition to the sulfur atom contained in mercapto group and at least one internal releasing agent and then casting and polymerizing the mixture.

Abstract: A composition for a urethane-base plastic lens, comprising:(a) at least one ester compound selected from the group consisting of isocyanate compounds, isothiocyanate compounds and isocyanato-containing isothiocyanate compounds,(b) at least one active hydrogen compound selected from the group consisting of hydroxyl compounds, mercapto compounds and mercapto-containing hydroxyl compounds,(c) a tertiary amine, and(d) a Lewis acid;a plastic lens obtained by heating and curing the composition, and a process for the production of the plastic lens. The composition has a long pot life and can produce an optically uniform plastic lens in a short time.

Abstract: A novel polythiol having four or more functional groups, a process for producing the polythiol comprising reacting thiourea with a specific compound, a sulfur-containing urethane-based resin prepared from the polythiol and a lens made of the resin. The resin has a high refractive index, and low dispersion of refractive index, is lightweight, colorless and transparent, has no optical distortion, and has excellent characteristics in weatherability, dye-affinity, heat resistance, impact resistance and machinability.

Abstract: One aspect of the present invention relates to a process for preparing plastic lenses having a high-refractive index comprising forming a mixture containing one or more polyisocyanate compounds; one or more active hydrogen compounds selected from the group consisting of a polyol compound having no sulfur atom, a polyol compound having at least one sulfur atom, and a polythiol compound having at least one sulfur atom in addition to the sulfur atom contained in mercapto group and at least one internal releasing agent and then casting and polymerizing the mixture.

Abstract: A process is provided for the preparation of an aliphatic polyisocyanate. Upon reacting an aliphatic polyamine or its hydrochloride or carbonate with phosgene in an inert liquid medium, the reaction is conducted while charging an inert gas into a reaction system.

Abstract: A method for stabilizing an isocyanate compound by adding 10-5000 ppm of phenol to the isocyanate compound, and also an isocyanate composition so stabilized. In the isocyanate composition stabilized by the above method, coloring due to time-dependent changes and the occurrence of turbidity through self-polymerization are both suppressed so that it shows outstanding storage stability compared with a corresponding isocyanate composition containing a conventional stabilizer.

Abstract: Optical urethane resins according to the present invention are each obtained by reacting an active hydrogen compound with an isocyanate compound containing as a stabilizer a phenolic compound. Owing to their low yellowness, high light transmittance and optical-strain-free quality, these resins are useful as optical materials for plastic lenses or the like which are required to be colorless, transparent and uniform.

Abstract: The present invention relates to a process for producing a plastic lens having a high refractive index and profile regularity comprising forming a mixture of one or more of sulfur-containing aromatic polyisocyanate compounds, one or more of active hydrogen compounds selected from the group consisting of polyol compounds and polythiol compounds, and at least one internal mold releasing agent, and subjecting the resulting mixture to casting polymerization, and a plastic lens obtained according to the process.

Abstract: The present invention relates to a process for producing a resin useful in plastic lenses, to plastic lenses containing the resin and to a process for producing the lenses.