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: 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 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 resin useful in preparing plastic lenses having a high refractive index comprising reacting an aliphatic polyisocyanate compounds having at least one sulfur atom with one or more of active hydrogen compounds selected from the group consisting of a polyol, a polythiol having sulfur atoms only in a mercapto groups, and a polythiol having at least one sulfur atom other than in the mercapto groups; lenses containing the above-mentioned resin; and a method for the preparation thereof characterized by adding an internal release agent to the mixture of the above-mentioned raw materials in casting lenses from the resin; and lenses obtained by this method.

Abstract: A process for producing a plastic lens having a high refractive index and profile regularity which includes 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. Then subjecting the resulting mixture to casting polymerization, to form the plastic lens.

Abstract: Diphenylamines or N,N'-diphenyl-phenylenediamines can be obtained by heat-reacting an aniline or a phenylenediamine with preferably an excess of a phenol in an amount of 4 to 20 moles per mole of the aniline or phenylenediamine in th presence of a hydrogen transfer catalyst and a cyclohexanone corresponding to said phenol.The excess phenol used in the reaction undergoes reduction in the reaction system to form a cyclohexanone, which in turn reacts with the aniline or phenylenediamine to form a Schiff base and is thus consumed. The Schiff base forms the intended product by means of a dehydrogenation reaction, and the hydrogen evolved at this time reduces the phenol to form a cyclohexanone.The phenol present in excess thus becomes in the system a solvent, a starting material for the cyclohexanone, and an acceptor of the hydrogen that forms as a by-product at the time of formation of the intended product.

Abstract: Disclosed herein are a novel and highly refractive S-alkyl thiocarbamate base resin useful in preparing lenses and a process for producing the resin comprising reacting one or more of polyisocyanate compounds and one or more of mercapto compound having at least one hydroxyl group, a plastic lens made of the resin, and a process for making a plastic lens of high profile regularity from the resin by using internal mold releasing agents in the casting polymerization process.

Abstract: Polyurethane base lens resins obtained by reacting one or more of sulfur-containing polyisocyanates compound with one or more of sulfur-containing polyols, and polyurethane base lenses comprising these resins are disclosed.A method for preparing polyurethane base lenses which comprises adding internal mold releasing agents to the mixture of the above polyisocyanates and polyols prior to casting polymerization is also disclosed.

Abstract: A process for producing a cyclic urea is provided. The process comprises reacting a diamine expressed by the formula (II)R-HN-R'-NH-R (II)wherein R represents hydrogen atom or a lower alkyl group and R' represent dimethylene group, a lower alkyl group-substituted dimethylene group, trimethylene group, a lower alkyl group-substituted trimethylene group, tetramethylene group, a lower alkyl group-substituted tetramethylene group, but a case where R represents hydrogen atom and R' represent dimethylene group, a case where R represents hydrogen atom and R' represents a lower alkyl group-substituted dimethylene group and a case where R represent methyl group and R' represents dimethylene group are excluded, with phosgene in the presence of a dehydrochlorinating agent. In the process, the diamine is first converted to its hydrochloride, followed by reacting the hydrochloride with phosgene in water solvent while maintaining a pH of the reaction liquid in the range of 5.0 to 8.

Abstract: A process for producing a cyclic diamine which comprises reacting a diamine of the formulaR--HN--R'--NH--R (II)wherein R represents a lower alkyl group and R' represents a lower alkyl group-substituted dimethylene group, trimethylene group, a lower alkyl group-substituted trimethylene group, tetramethylene group or a lower alkyl group-substituted tetramethylene group with urea in the presence of a polar solvent and at 180.degree. C. or higher, to obtain a cyclic urea ##STR1## wherein R and R' are each as defined above, the production yield being more improved by carrying out the initial period reaction at 140.degree. C. or lower.

Abstract: Diphenylamines or N,N'-diphenyl-phenylenediamines can be obtained by heat-reacting an aniline or a phenylenediamine with preferably an excess of a phenol in an amount of 4 to 20 moles per mole of the aniline or phenylenediamine in the presence of a hydrogen transfer catalyst and a cyclohexanone corresponding to said phenol.The excess phenol used in the reaction undergoes reduction in the reaction system to form a cyclohexanone, which in turn reacts with the aniline or phenylenediamine to form a Schiff base and is thus consumed. The Schiff base forms the intended product by means of a dehydrogenation reaction, and the hydrogen evolved at this time reduces the phenol to form a cyclohexanone.The phenol present in excess thus becomes in the system a solvent, a starting material for the cyclohexanone, and an acceptor of the hydrogen that forms as a by-product at the time of formation of the intended product.

Abstract: Diphenylamines or N,N'-diphenyl-phenylenediamines can be obtained by heat-reacting an aniline or a phenylenediamine with preferably an excess of a phenol in an amount of 4 to 20 moles per mole of the aniline or phenylenediamine in the presence of a hydrogen transfer catalyst and a cyclohexanone corresponding to said phenol.The excess phenol used in the reaction undergoes reduction in the reaction system to form a cyclohexanone, which in turn reacts with the aniline or phenylenediamine to form a Schiff base and is thus consumed. The Schiff base forms the intended product by means of a dehydrogenation reaction, and the hydrogen evolved at this time reduces the phenol to form a cyclohexanone.The phenol present in excess thus becomes in the system a solvent, a starting material for the cyclohexanone, and an acceptor of the hydrogen that forms as a by-product at the time of formation of the intended product.

Abstract: Disclosed herein is a colorless transparent plastic lens having high refractivity and low dispersion. The lens is light, has heat resistance sufficient for post processing, and is excellent in grinding machinability and impact resistance. It is made of a sulfur-containing urethane resin, which is a polymer of a specific polythiol and a particular polyisocyanate of at least bifunctionality.

Abstract: A sulfur-containing polyurethane base lens resin is obtained by reacting one or more isocyanate compounds, which have two or more NCO groups, with one or more OH-containing compounds, which have two or more OH groups, in such proportions that the molar ratio of NCO groups to OH groups ranges from 0.5 to 1.5. At least one of said one or more OH-containing compounds contains one or more sulfur atoms in the molecule thereof. The total content of sulfur atoms in all OH-containing compounds is 20 wt. % or higher.

Abstract: Disclosed herein are a high-refractivity plastic lens resin obtained by polymerizing under heat at least one polyisocyanate (I): ##STR1## wherein X means a hydrogen, chlorine or bromine atom or a methyl or ethyl group, Z is a hydrogen atom or a methyl group, a stands for an integer of 1-4, b is an integer of 2-4, and a+b is not greater than 6 (a+b.ltoreq.6), with at least one polythiol (II): ##STR2## wherein R means a methyl, ethyl, chloromethyl or bromomethyl group, m stands for an integer of 0-2 and n is 4-m and/or at least one polythiol (III): ##STR3## wherein X means a hydrogen, chlorine or bromine atom or a methyl or ethyl group, Y denotes an oxygen or sulfur atom, r stands for 0 or 1, s is an integer of 0-2, p is an integer of 2-4, q is an integer of 1-4 and p+q is not greater than 6 (p+q.ltoreq.6), in such amounts that the --NCO/--SH molar ratio falls within 0.5-3.0, as well as a lens made of the above resin.

Abstract: An improved process of producing 1, 3-dialkyl-2-imidazolidinones directly from N, N'-dialkylethylenediamine and urea with a high yield is provided, which process comprises reacting a N, N'-dialkylethylenediamine of the formula ##STR1## wherein R represents --CH.sub.3, --C.sub.2 H.sub.5, --C.sub.3 H.sub.7 or --C.sub.4 H.sub.9, with urea at 180.degree. C. or higher in the presence of a polar solvent, to obtain a 1, 3-dialkyl-2-imidazolidinone of the formula ##STR2## and preferably comprises carrying out the reaction at two stages, that is, the initial period reaction being carried out at 140.degree. C. or lower to from a 1, 1'-dialkyl-1 1'-dimethylenebisurea and successively the latter reaction being carried out at 180.degree. C. or higher.

Abstract: An S-alkyl thiocarbamate base lens resin is obtained by reacting one or more NCO-containing compounds, such as xylylene diisocyanate, hexamethylene diisocyanate and/or tetrachloroxylylene diisocyanate, with one or more SH-containing aliphatic compounds, for example, a di(2-mercaptoalkyl) ether.

Abstract: A sulfur-containing polyurethane base lens resin is obtained by reacting one or more isocyanate compounds, which have two or more NCO groups, with one or more OH-containing compounds, which have two or more OH groups, in such proportions that the molar ratio of NCO groups to OH groups ranges from 0.5 to 1.5. At least one of said one or more OH-containing compounds contains one or more sulfur atoms in the molecule thereof. The total content of sulfur atoms in all OH-containing compounds is 20 wt. % or higher.

Abstract: A process for producing 1,3-dimethyl-2-imidazolidinone with a high yield which comprises reacting N,N'-dimethylethylene diamine and/or its hydrochloride with phosgene in the presence of a substantial amount of water and a dehydrochlorinating agent. Particularly, higher yield is attained by carrying out the reaction in water medium while controlling a pH to the range of 3.0 to 10.0 by adding a dehydrochlorinating agent.