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: The present invention discloses a sulfur-containing urethane-based resin composition of the present invention is directed to a sulfur-containing urethane-based resin composition which comprises a polythiol compound represented by formula (1): ##STR1## wherein X.sub.1, X.sub.2 and X.sub.3 each is a hydrogen atom or a mercapto group; x, y and z each is an integer of 0 to 8; and in their combinations, formula (1) has at least two mercapto groups,a polyiso(thio)cyanate compound, and a compound having two or more reactive unsaturated groups in an amount of 30 to 70% by weight based on the total weight of the composition, or a sulfur-containing urethane-based resin composition which comprises the polythiol compound represented by formula (1), the polyiso(thio)cyanate compound, the compound having two or more reactive unsaturated groups in an amount of 10 to 70% by weight based on the total weight, and a photopolymerization catalyst.

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: The present invention relates to a high surface hardness transparent resin having excellent scratch resistance, heat resistance and chemical resistance, a glazing material, a protective cover for display devices, an optical lens and a hard coat material comprising the aforesaid resin, and a novel polymerizable monomer which is useful as a raw material of the above-mentioned resin.The monomer is represented by the formula (I) ##STR1## (wherein R is an aliphatic residue having or non having an halogen atom, an oxygen atom, an alicyclic ring, a heterocyclic ring or an aromatic ring, an alicyclic residue, or a heterocyclic residue, n is an integer of 1 to 4, when n=1, X is oxygen or sulfur, when n.gtoreq.

Abstract: The present invention relates to a polysulfide based resin lens, comprising a mixture of at least one epoxy resin having at least two epoxy groups, and at least one polythiol compound having at least two mercaptan groups, and at least one internal release agent, which is cast polymerized, and the process for preparing the same.

Abstract: A mercapto compound represented by the following formula (1): ##STR1## is obtained by reacting, in the presence of a mineral acid, thiourea with a compound represented by the following formula (2): ##STR2## wherein X means a hydroxyl group or a chlorine or bromine atom, and then adding a base to alkalinize the reaction mixture so that the reaction product is hydrolyzed.The mercapto compound represented by the formula (1) can be reacted with at least one cyanate compound selected from the group consisting of polyisocyanate compounds, polyisothiocyanate compounds and isocyanate-group-containing isothiocyanate compounds to form a sulfur- containing urethane resin. A lens made of the resin is colorless and transparent, has high refractive index and low dispersion characteristics, and is excellent especially in heat resistance.

Abstract: The present invention discloses a composition for high refractive index plastic lens consisting of a monomer mixture wherein a particular aliphatic thiol compound is added to a polyisocyanate represented by general formula (1): ##STR1## wherein each X represents a hydrogen atom or a methyl group; each R represents a chlorine atom, a bromine atom, a methyl group or an ethyl group; m represents an integer of 0-4; and n represents an integer of 2-4, and a polythiol of formula (2): ##STR2## and a high refractive index plastic lens made of a urethane-containing resin obtained by polymerizing said composition.

Abstract: A mercapto compound represented by the following formula (1): ##STR1## is obtained by reacting, in the presence of a mineral acid, thiourea with a compound represented by the following formula (2): wherein X means a hydroxyl group or a chlorine or bromine atom, and then adding a base to alkalinize the reaction mixture so that the reaction product is hydrolyzed.The mercapto compound represented by the formula (1) can be reacted with at least one cyanate compound selected from the group consisting of polyisocyanate compounds, polyisothiocyanate compounds and isocyanate-group-containing isothiocyanate compounds to form a sulfur-containing urethane resin lens made of the resin is colorless and transparent, has high refractive index and low dispersion characteristics, and is excellent especially in heat resistance.

Abstract: The present invention relates to a high surface hardness transparent resin having excellent scratch resistance, heat resistance and chemical resistance, a glazing material, a protective cover for display devices, an optical lens and a hard coat material comprising the aforesaid resin, and a novel polymerizable monomer which is useful as a raw material of the above-mentioned resin.The monomer is represented by the formula (I) ##STR1## (wherein R is an aliphatic residue having or not having an halogen atom, an oxygen atom, an alicyclic ring, a heterocyclic ring or an aromatic ring, an alicyclic residue, or a heterocyclic residue, n is an integer of 1 to 4, when n=1, X is oxygen or sulfur, when n.gtoreq.2, X's are all oxygen or all sulfur, one X is oxygen while the other X or X's are sulfur, one X is sulfur while the other X or X's are oxygen, or two X's are oxygen while the other X's are sulfur).

Abstract: A novel polymerizable monomer represented by the formula (I) useful as a raw material for the high surface hardness transparent resin. ##STR1## wherein R is an aliphatic residue having or not having an oxygen atom, an alicyclic ring, a heterocyclic ring or an aromatic ring, or an alicyclic residue, l is 0 or 1, each of i and j is an integer of 1 or more, and when l=0, i=j=1, when l=1, (i+j) is 4 or less, when j=1, X is oxygen or sulfur, when j.gtoreq.2, all X's are oxygen or sulfur, or one X is oxygen and the other X's are sulfur, or one X is sulfur and the other X's are oxygen.The high surface hardness transparent resin comprises a crosslinked polymer prepared by copolymerizing a monomer (A) represented by the formula (I) as above and a monomer (B) containing one or more functional groups of at least one kind selected from the group consisting of CH.sub.2 .dbd.CH--C(O)--O--, CH.sub.2 .dbd.C(CH.sub.

Abstract: The present invention relates to a mercapto compound, a process for preparing the mercapto compound, a process for preparing a polythiourethane base resin containing the mercapto compound, and a process for preparing plastic lenses containing the resin.

Abstract: The present invention relates to a process for preparing a hard transparent resin comprising polymerizing a monomer (A) having both a functional group of the following formula (I): ##STR1## wherein X is selected from the group consisting of an oxygen atom and a sulfur atom,and a functional group selected from the group consisting of a functional group of the formula (II):CH.sub.2 CR--COO-- (II)wherein R is selected from the group consisting of hydrogen and methyl group,and a functional group of the formula (III): ##STR2## The invention also provides a process for preparing a transparent resin comprising copolymerizing monomer (A) with a monomer (B) having at least one functional group selected from the group consisting ofCH.sub.2 CH.dbd.COO--,CH.sub.2 .dbd.C(CH.sub.3)--COO--, and ##STR3## This resin can be suitably used as a glazing material, and in the manufacture of optical lenses, optical information recording medium substrates, etc.

Abstract: The present invention relates to a transparent resin which has a high surface hardness and which is excellent in scratch resistance, heat resistance and chemical resistance, a glazing material, a protective cover for display devices, an optical lens and a hard coat material comprising the above-mentioned resin, and a novel polymerizable monomer represented by the formula (I) useful as a raw material for the high surface hardness transparent resin. ##STR1## wherein R is an aliphatic residue having or not having an oxygen atom, an alicyclic ring, a heterocyclic ring or an aromatic ring, or an alicyclic residue, l is 0 or 1, each of i and j is an integer of 1 or more, and when l=0, i=j=1, when l=1, (i+j) is 4 or less, when j=1, X is oxygen or sulfur, when j.gtoreq.2, all X's are oxygen or sulfur, or one X is oxygen and the other X's are sulfur, or one X is sulfur and the other X's are oxygen.

Abstract: There are here provided a low-hygroscopic sulfur-containing and crosslinked structure-having urethane resin, urethane resin plate and shape-recoverable molding article which is prepared by first selecting a polyisocyanate compound having m (which is an integer of 2 or more) isocyanate groups in one molecule and a polythiol compound having n (which is an integer of 2 or more) thiol groups in one molecule so that the total number of m+n may be 5 or more, and then polymerizing the composition of the polyisocyanate compound and the polythiol compound; a low-hygroscopic sulfur-containing urethane coating material which comprises the above composition; and a low-hygroscopic sulfur-containing urethane adhesive which comprises the composition. In the resin of the present invention, its water absorption is as low as a level of 0.02 to 0.20% by weight, and its adhesion to a hard coating film is also good.

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.