Use of sulfur-containing acid phosphoric ester as internal release agent

Abstract: An internal release agent comprises a sulfur-containing acid phosphoric esters selected from the group consisting of thiophosphoric acid esters and dithiophosphoric acid esters of the formula, where X and Y are independently selected from the group consisting of an oxygen atom and a sulfur atom, at least one of X and Y is a sulfur atom, and R₁ and R₂ are independently alkyl groups.

Description: BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an internal release agent, a method for molding a resin using the internal release agent and a resin molded article. Description of the Related Art There are known various methods for molding resins such as casting molding, injection molding and the like. In each method, so-called release agents are used for improving releasability between a molded article and a mold. In particular, urethane resin and epoxy resins have a strong adhesion and therefore, it is essential to use a release agent. Release agents are generally classified into two groups, that is, external release agents and internal release agents. External release agents should be applied to the inner surface of a mold each time of molding procedure. Therefore, there are various problems as shown below. The productivity of the molded articles is poor, an external release agent is transferred onto the surface of the resulting molded articles resulting in forming irregular portions on the surface of the molded article and causing defective coating and dyeing, and further a transparent resin molded article becomes turbid. On the contrary, an internal release agent is added to a resin producing monomers in advance. It is not necessary to apply it to a mold each time upon molding. Therefore, an internal release agent favors improvement in productivity. As internal release agents, there are known internal release agents for urethane resin molding, for example, fluorine type nonionic surface active agents, silicon type nonionic surface active agents, alkyl quaternary ammonium salts, acid phosphoric esters, liquid paraffin, waxes, higher fatty acids and metal salts thereof, higher fatty acid esters, higher aliphatic alcohols, bisamides, polysiloxanes, and aliphatic amine ethylene oxide adducts (Japanese Patent Application Laid-open No. Hei 1 - 295201). Phosphoric acid esters having polyether substituents have been recently proposed (Japanese Patent Application Laid-open No. Hei 3 - 287641). For reaction injection molding of urethane resins, zinc stearate is generally used, but zinc stearate is not so soluble in the starting materials that various compatibilizers have been proposed (Japanese Patent Application Laid-open No. Hei 3 - 273030 and Japanese Patent Publication No. Hei 3 - 27586). In the molding of epoxy resins, there are known a method using zinc stearate as an internal release agent (Japanese Patent Application Laid-open No. Hei 1 - 213602), a method using fluorine type nonionic surface active agents, silicon type nonionic surface active agent, alkyl quaternary ammonium salts, and acid phosphoric esters as internal release agents (Japanese Patent Application Laid-open No. Hei 3 - 81320), and methods of using both an external release agent and an internal release agent (Japanese Patent Application Laid-open Nos. Sho 63 - 144302 and 63 - 144303). Further, in the molding of polyolefin resins, there are used aliphatic alcohols, aliphatic ester, phthalic acid esters, triglycerides, fluorine type surface active agents, and higher fatty acid metal salts as internal release agents (Japanese Patent Application Laid-open Nos. Hei 2 - 84409 and 2 - 44301). In the molding of polycarbonate resins, there are used higher fatty acid esters, waxes, liquid paraffin, silicone oil, and alkyl glyceryl ethers as internal release agents (Japanese Patent Application Laid-open Nos. Hei 1 - 315460 and 1 - 315459). For molding acrylic resins, there are generally used molding methods where higher alcohols, higher fatty acid esters, higher fatty acids and the like are used as internal release agents (Japanese Patent Application Laid-open No. Hei 2 - 105844). The known internal release agents as above are effective and improve productivity of the molded articles as compared with external release agents. However, the releasing function is not sufficient and thereby, the resins sometimes remain on the surface of molds and in the case of molds made of glass, glass is peeled off sometimes. In addition, an excess stress is applied due to the resistance upon releasing and thereby the molded article is liable to warp or to be strained. When internal release agents are used in an amount sufficient to release satisfactorily, the molded articles are liable to become turbid. Such drawbacks are fatal to molding optical products such as plastic lenses particularly requiring a surface accuracy and transparency, light disc, and deteriorate the commodity value to a great extent. In view of the foregoing, development of a new internal release agent has been strongly demanded which has a sufficient releasing function and does not deteriorate transparency in the case of molding a transparent resin. SUMMARY OF THE INVENTION An object of the present invention is the use of an internal release agent capable of exhibiting at least partly a high releasability, suppression of occurrence of strain in a molded article upon releasing, prevention of the resin from dirtying the surface of a mold, and substantially no adverse influence on transparency when a transparent resin is molded. Another object of the present invention is to provide a method for molding a resin with the internal release agent. A further object of the present invention is to provide a resin molded article produced using the internal release agent. One aspect of the present invention is the use of at least one sulfur-containing acid phosphoric ester selected from the group consisting of thiophosphoric acid esters and dithiophosphoric acid esters of the formula, where X and Y are independently selected from the group consisting of an oxygen atom and a sulfur atom, at least one of X and Y is a sulfur atom, and R 1 and R 2 are independently alkyl groups as internal release agent. According to another aspect of the present invention, there is provided a method for molding a resin comprising using the internal release agent as mentioned above. According to a further aspect of the present invention, there is provided a resin molded article produced by the method for molding as mentioned above. DESCRIPTION OF THE PREFERRED EMBODIMENTS The thiophosphoric acid ester of the formula (1) as above has the following equilibrium of the formula (2) and is known to be present in the form of the mixture (Methoden der Organischen Chemie, Band XII/2, P. 604, 1964). Conventional uses of sulfur-containing phosphoric acid esters are mainly starting materials for insectcides and germicide (U.S. Pat. No. 3,742,097) and thereby, concern a field of agricultural chemicals. Therefore, it is not predictable at all from the conventional uses of the sulfur-containing phosphoric acid ester that such compound can be used as a useful internal release agent. Exemplary suitable internal release agents of the present invention include: dimethyl thiophosphate, diethyl thiophosphate, dipropyl thiophosphate, diisopropyl thiophosphate, dibutyl thiophosphate, dioctyl thiophosphate, didecyl thiophosphate, didodecyl thiophosphate, ditetradodecyl thiophosphate, dihexadecyl thiophosphate, and dioctadecyl thiophosphate. Exemplary suitable dithiophosphoric acid esters of the formula (1) include: dimethyl dithiophosphate, diethyl dithiophosphate, dipropyl dithiophosphate, diisopropyl dithiophosphate, dibutyl dithiophosphate, dihexyl dithiophosphate, dioctyl dithiophosphate, didecyl dithiophosphate, didodecyl dithiophosphate, ditetradecyl dithiophosphate, dihexadecyl dithiophosphate, and dioctadecyl dithiophosphate. Resins to which the internal release agent is applied are: As thermosetting resins, urethane resins, epoxy resins, polyolefin resins, polyene-polythiol resins, unsaturated polyester resins, phenolic resins, furan resins, xylene resins, formaldehyde resins, ketone resins, urea resins, melamine resins, aniline resins, sulfonamide resins, alkyd resins, and composite resins thereof. As thermoplastic resins, polyolefin resins, polycarbonate resins, thermoplastic polyester resins, polyether resins, polyamide resins, polyimide resins, urethane resins, polyvinylketone resins, polyvinyl ether resins, and composite resins thereof. Molding methods may be appropriately selected depending on the characteristics of resins. In general, thermosetting resins, are molded by casting polymerization methods, compression molding methods and the like, and thermoplastic resins are molded by injection molding methods, and extrusion molding methods. The present invention may be effected by any molding methods. In the case of casting polymerization, a sulfur-containing acid phosphoric ester may be added to monomer or monomer mixtures in advance, followed by polymerizing the resulting mixture in a mold. According to other molding methods, resin powder or pellets may be molded by mixing resin powder with a sulfur-containing acid phosphoric ester, melted or plasticized, poured into a mold and then molded, or when producing resin powder or pellets, a sulfur-containing acid phosphoric ester may be added in advance and the resulting resin powder or pellets may be directly molded. Or any other methods may be used. The amount of the sulfur-containing acid phosphoric ester used is preferably 0.01 - 5 % by weight based on the total amount of monomers in the case of casting polymerization of urethane resins or epoxy resins which are difficult to be released. When the amount is less than 0.01 % by weight, the releasing becomes poor. When it exceeds 5 % by weight, various inherent physical properties of the resins may be adversely affected. In the case of injection molding of thermoplastic resins such as polyolefin resins, polycarbonate resins, and acrylic resins, releasing is relatively easy, and therefore, the amount of sulfur-containing acid phosphoric ester nay be preferably as low as 0.01 - 1 % by weight. In the formula (1), the alkyl groups of R 1 and R 2 may be similar or dissimilar, and in general, the shorter the alkyl chain, the higher the releasing function. Therefore, sulfur-containing acid phosphoric esters having C 1 - C 8 alkyl groups are preferably used. However, when a particularly high temperature is necessary, for example, in the case of injection molding, it is preferable to use sulfur-containing acid phosphoric esters of high boiling points, and in such a case, alkyl groups up to C 18 are preferably used. Sulfur-containing acid phosphoric esters having alkyl groups of more than C 18 exhibit lower release function, and in the case of molding transparent resins, the molded articles are liable to be turbid. As the material for mold, there may be used stainless steels, copper, aluminum, alloys thereof, wood, ceramics and glass generally used as molds. In the following, some of the representative resins which may be used in the present invention are explained more in detail. As urethane resins, there may be mentioned resins prepared by polymerizing at least one iso(thio)cyanate compound selected from the group consiting of polyisocyanate compounds, polyisothiocyanate compounds and isothiocyanate compounds having an isocyanate group with at least one active hydrogen compound selected from the group consisting of polyol compounds, polythiol compounds and hydroxythiol compounds. Upon polymerization molding, there may be added various additives such as known chain extender, crosslinking agent, photo-stabilizer, UV absorber, antioxidant, oil soluble dye, filler, and polymerization catalyst, depending on the purpose. Exemplary suitable polyisocyanate compounds include: aliphatic polyisocyanates such as ethylene diisocyanate, trimethylenediisocyanate, tetramethylenediisocyanate, hexamethylenediisocyanate, octamethylenediisocyanate, nonamethylenediisocyanate, 2,2'-dimethylpentanediisocyanate, 2,2,4-trimethylhexanediisocyanate, decamethylenediisocyanate, butenediisocyanate, 1,3-butadiene-1,4-diisocyanate, 2,4,4-trimethylhexamethylenediisocyanate, 1,6,11-undecanetriisocyanate, 1,3,6-hexamethylenetriisocyanate, 1,8-diisocyanato-4-isocyanatomethyloctane, 2,5,7-trimethyl-1,8-diisocyanato-5-isocyanatomethyloctane, bis(isocyanatoethyl)carbonate, bis(isocyanatoethyl)ether, 1,4-butyleneglycoldipropylether-α,α'-diisocyanate, lysine diisocyanate methyl ester, lysine triisocyanate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate, 2-isocyanatopropyl-2,6-diisocyanatohexanoate, xylylenediisocyanate, bis(isocyanatoethyl)benzene, bis(isocyanatopropyl)benzene, α,α,α',α'-tetramethylxylylenediisocyanate, bis(isocyanatobutyl)benzene, bis(isocyanatomethyl)naphthalene, bis(isocyanatomethyl)diphenylether, bis(isocyanatoethyl)phthalate, mesitylylenetriisocyanate, 2,6-di(isocyanatomethyl)furan; alicyclic polyisocyanates such as isophoronediisocyanate, bis(isocyanatomethyl)cyclohexane, dicyclohexylmethanediisocyanate, cyclohexanediisocyanate, methylcyclohexanediisocyanate, dicyclohexyldimethylmethanediisocyanate, 2,2'-dimethyldicyclohexylmethanediisocyanate, bis(4-isocyanato-n-butylidene)pentaerythritol, dimer acid diisocyanate, 2-isocyanatomethyl-3-(3-isocyanatopropyl)-5-isocyanatomethyl-bicyclo[2,2,1]-heptane, 2-isocyanatomethyl-3-(3-isocyanatopropyl)-6-isocyanatomethyl-bicyclo[2,2,1]-heptane, 2-isocyanatomethyl-2-(3-isocyanatopropyl)-5-isocyanatomethyl-bicyclo[2,2,1]-heptane, 2-isocyanatomethyl-2-(3-isocyanatopropyl)-6-isocyanatomethyl-bicyclo[2,2,1]-heptane, 2-isocyanatomethyl-3-(3-isocyanatopropyl)-5-(2-isocyanatoethyl)-bicyclo-[2,2,1]-heptane, 2-isocyanatomethyl-3-(3-isocyanatopropyl)-6-(2-isocyanatoethyl)-bicyclo-[2,2,1]-heptane, 2-isocyanatomethyl-2-(3-isocyanatopropyl)-5-(2-isocyanatoethyl)-bicyclo-[2,2,1]-heptane, 2-isocyanatomethyl-2-(3-isocyanatopropyl)-6-(2-isocyanatoethyl)-bicyclo-[2,2,1]-heptane, 2,5 (or 6)-bis(isocyanatomethyl)-bicyclo-[2,2,1]-heptane; and aromatic polyisocyanates such as phenylene diisocyanate, tolylene diisocyanate, ethylphenylene diisocyanate, isopropylphenylene diisocyanate, dimethylphenylene diisocyanate, diethylphenylene diisocyanate, diisopropylphenylene diisocyanate, trimethylbenzene triisocyanate, benzene triisocyanate, naphthalene diisocyanate, methylnaphthalene diisocyanate, biphenyl diisocyanate, tolidine diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, bibenzyl-4,4'-diisocyanate, bis(isocyanatophenyl)ethylene, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, triphenylmethane triisocyanate, polymeric MDI, naphthalene triisocyanate, diphenylmethane-2,4,4'-triisocyanate, 3-methyldiphenylmethane-4,6,4'-triisocyanate, 4-methyl-diphenylmethane-3,5,2',4', 6'-pentaisocyanate, phenylisocyanatomethylisocyanate, phenylisocyanatoethylisocyanate, tetrahydronaphthalenediisocyanate, hexahydrobenzenediisocyanate, hexahydrodiphenylmethane-4,4'-diisocyanate, diphenylether diisocyanate, ethylene glycol diphenylether diisocyanate, 1,3-propyleneglycol diphenylether diisocyanate, benzophenone diisocyanate, diethylene glycol diphenylether diisocyanate, dibenzofuran diisocyanate, carbazole diisocyanate, ethylcarbazole diisocyanate, and dichlorocarbozole diisocyanate. Exemplary suitable polyisocyanate compounds containing sulfur atom include: sulfur-containing aliphatic isocyanates such as thiodiethyl diisocyanate, thiodipropyl diisocyanate, thiodihexyl diisocyanate, dimethylsulfone diisocyanate, dithiodimethyl diisocyanate, dithiodiethyl diisocyanate, dithiodipropyl diisocyanate,; aromatic isocyanates containing sulfide bond such as diphenylsulfide-2,4'-diisocyanate, diphenylsulfide-4,4'-diisocyanate, 3,3'-dimethoxy-4,4'-diisocyanate dibenzylthioether, bis(4-isocyanatomethylphenyl)sulfide, 4,4'-methoxyphenylthioethyleneglycol-3,3'-diisocyanate,; aromatic isocyanates containing disulfide bond such as diphenyldisulfide-4,4'-diisocyanate, 2,2'-dimethyldiphenyldisulfide-5,5'-diisocyanate, 3,3'-dimethyldiphenyldisulfide-5,5'-diisocyanate, 3,3'-dimethyldiphenyldisulfide-6,6'-diisocyanate, 4,4'-dimethyldiphenyldisulfide-5,5'-diisocyanate, 3,3'-dimethoxydiphenyldisulfide-4,4'-diisocyanate, 4,4'-dimethoxydiphenyldisulfide-3,3'-diisocyanate,; aromatic isocyanates containing sulfone bond such as diphenylsulfone-4,4'-diisocyanate, diphenylsulfone-3,3'-diisocyanate, benzidinesulfone-4,4'-diisocyanate, diphenylmethanesulfone-4,4'-diisocyanate, 4-methyldiphenylsulfone-4,4'-diisocyanate, 4,4'-dimethoxyphenylsulfone-3,3'-diisocyanate, 3,3'-dimethoxy-4,4'-diisocyanatobenzyldisulfone, 4,4'-dimethyldiphenylsulfone-3,3'-diisocyanate, 4,4'-di-tert-butyldiphenylsulfone-3,3'-diisocyanate, 4,4'-methoxyphenylethylenesulfone-3,3'-diisocyanate, 4,4'-dicyclodiphenylsulfone-3,3'-diisocyanate,; aromatic isocyanates containing sulfonic acid ester bond such as 4-methyl-3-isocyanatophenylsulfonyl-4'-isocyanatophenol ester, 4-methoxy-3-isocyanate phenylsulfonyl-4'-isocyanatophenol ester,; aromatic isocyanates containing sulfonamide bond such as 4-methyl-3-isocyanatophenylsulfonylanilide-3'-methyl-4'-isocyanate, diphenylsulfonyl-ethylenediamine-4,4'-diisocyanate, 4,4'-methoxyphenylsulfonyl-ethylenediamine-3,3'-diisocyanate, 4-methyl-3-isocyanatophenylsulfonylanilide-4-methyl-3'-isocyanate,; sulfur-containing heterocyclic compounds such as thiophene-2,5-diisocyanate; and 1,4-dithiane-2,5-diisocyanate. Exemplary suitable polyisothiocyanate compound include: aliphatic polyisothiocyanate such as 1,2-diisothiocyanatoethane, 1,3-diisothiocyanatopropane, 1,4-diisothiocyanatobutane, 1,6-diisothiocyanatohexane, p-phenylenediisopropylidene diisothiocyanate,; aliphatic isothiocyanate such as cyclohexane diisothiocyanate; aromatic polyisothiocyanate such as 1,2-diisothiocyanatobenzene, 1,3-diisothiocyanatobenzene, 1,4-diisothiocyanatobenzene, 2,4-diisothiocyanatotoluene, 2,5-diisothiocyanato-m-xylene, 4,4-diisothiocyanato-1,1'-biphenyl, 1,1'-methylenebis(4-isothiocyanatobenzene), 1,1'-methylenebis(4-isothiocyanato-2-methylbenzene), 1,1'-methylenebis(4-isothiocyanato-3-methylbenzene), 1,1'-(1,2-ethanediyl)bis(4-isothiocyanatobenzene), 4,4'-diisothiocyanatobenzophenone, 4,4'-diisothiocyanato-3,3'-dimethylbenzophenone, benzanilide-3,4'-diisothiocyanate, diphenylether-4,4'-diisothiocyanate, diphenylamine-4,4'-diisocyanate,; heterocyclic ring-containing isothiocyanate such as 2,4,6-triisothiocyanato-3,5-triazine; and carbonylisothiocyanate such as hexanedioyldiisothiocyanate, nonanedioyldiisothiocyanate, carbonic diisothiocyanate, 1,3-benzenecarbonyldiisothiocyanate, 1,4-benzenecarbonyldiisothiocyanate, and (2,2'-bipyridine)-4,4'-dicarbonyldiisothiocyanate. Exemplary suitable polyisothiocyanates containing at least one sulfur atom other than isothiocyanato group include: sulfur-containing aliphatic polyisothiocyanate such as thiobis(3-isothiocyanatopropane), thiobis(2-isothiocyanatoethane), dithiobis(2-isothiocyanatoethane), sulfur-containing aromatic polyisothiocyanate such as 1-isothiocyanato-4-[(2-isocyanato)sulfonyl]benzene, thiobis(4-isothiocyanatobenzene), sulfonylbis(4-isothiocyanatobenzene), sulfinylbis(4-isothiocyanatobenzene), dithiobis(4-isothiocyanatobenzene), 4-isothiocyanato-1-[(4-isocyanatophenyl)sulfonyl]-2-methoxy-benzene, 4-methyl-3-isothiocyanatobenzenesulfonyl-4'-isocyanatophenyl ester, 4-methyl-3-isothiocyanatobenzenesulfonylanilide-3'-methyl-4'-isocyanate, and sulfur-containing heterocyclic compound such as thiophene-2,5-diisothiocyanate, and 1,4-dithiane-2,5-diisothiocyanate. Exemplary suitable isothiocyanate compounds containing isocyanato group include: aliphatic or alicyclic compound such as 1-isocyanato-3-isothiocyanatopropane, 1-isocyanato-5-isothiocyanatopentane, 1-isocyanato-6-isothiocyanatohexane, isothiocyanatocarbonylisocyanate, 1-isocyanato-4-isothiocyanatocyclohexane; aromatic compound such as 1-isocyanato-4-isothiocyanatobenzene, 4-methyl-3-isothiocyanato-1-isothiocyanatobenzene,; heterocyclic compound such as 2-isocyanato-4,6-diisothiocyanato-1,3,5-triazine,; and compounds containing sulfur atom other than isothiocyanato group such as 4-isothiocyanato-4'-isothiocyanatodiphenylsulfide, and 2-isothiocyanato-2'-isothiocyanatodiethyldisulfide. In addition, there may be used halogen-substituted compounds derived from the above-mentioned iso(thio)cyanate compounds such as the chloro- or bromo-substituted compounds, products of a biuret forming reaction of the above-mentioned compounds, products of the adduct reaction with trimethylolpropane, and the dimerized or trimerized reaction products. These compounds may be used alone or in combination. Exemplary suitable polyol compounds include: aliphatic polyol such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerine, trimethylolethane, trimethylolpropane, butanetriol, 1,2-methylglucoside, pentaerythritol, dipentaerythritol, tripentaerythritol, sorbitol, erythritol, threitol, ribitol, arabinitol, xylitol, allitol mannitol, dulcitol iditol glycol, inositol, hexanetriol, triglycerol, diglycerol triethylene glycol, polyethylene glycol, tris(2-hydroxyethyl)isocyanurate, cyclobutanediol, cyclopentanediol, cyclohexanediol, cycloheptanediol, cyclooctanediol, cyclohexanedimethanol, hydroxypropylcyclohexanol, tricyclo[5,2,1,0 2,6 ]decane-dimethanol, bicyclo[4,3,0]-nonanediol, dicyclohexanediol, tricyclo[5,3,1,1]dodecanediol, bicyclo[4,3,0]nonane-dimethanol, tricyclo[5,3,1,1]docedane-diethanol, hydroxypropyltricyclo[5,3,1,1]dodecanol, spiro[3,4]octanediol, butylcyclohexanediol, 1,1'-bicyclohexylidenediol, cyclohexanetriol, maltitol, lactose; aromatic polyol such as dihydroxynaphthalene, trihydroxynaphthalene, tetrahydroxynaphthalene, dihydroxybenzene, benzene triol, biphenyl tetraol, pyrogallol, (hydroxynaphthyl)pyrogallol, trihydroxyphenanthrene, bisphenol A, bisphenol F, xylyleneglycol, di(2-hydroxyethoxy)benzene, bisphenol A-bis(2-hydroxyethylether), tetrabromobisphenol A, tetrabromobisphenol A-bis(2-hydroxyethylether),; halogenated polyol such as dibromoneopentyl glycol,; high polymer polyol such as epoxy resins,; and further, condensation reaction products of the above-mentioned polyols with the following organic acids such as oxalic acid, glutamic acid, adipic acid, acetic acid, propionic acid, cyclohexane carboxylic acid, β-oxocyclohexane propionic acid, dimer acid, phthalic acid, isophthalic acid, salicylic acid, 3-bromopropionic acid, 2-bromoglycol, dicarboxycyclohexane, pyromellitic acid, butanetetracarboxylic acid, bromophthalic acid,; addition reaction products of the above-mentioned polyols with alkylene oxide such as ethylene oxide, propylene oxide; addition reaction products of alkylene polyamine with alkylene oxide such as ethylene oxide, propylene oxide; and polyol containing sulfur atom such as bis[4-(hydroxyethoxy)phenyl]sulfide, bis[4-(2-hydroxypropoxy)phenyl]sulfide, bis[4-(2,3-dihydroxypropoxy)phenyl]sulfide, bis[4-(4-hydroxycyclohexyloxy)phenyl]sulfide, bis[2-methyl-4-(hydroxyethoxy)-6-butylphenyl]sulfide, compounds formed by adding average three molecules or less of ethylene oxide and/or propylene oxide per one hydroxyl group of the above-mentioned sulfides, di-(2-hydroxyethyl)sulfide, 1,2-bis(2-hydroxyethylmercapto)ethane, bis(2-hydroxyethyl)disulfide, 1,4-dithiane-2,5-diol, bis(2,3-dihydroxypropyl)sulfide, tetrakis (4-hydroxy-2-thiobutyl)methane, bis(4-hydroxyphenyl)sulfone(Bisphenol S, trade name), tetrabromobisphenol S, tetramethylbisphenol S, 4,4'-thiobis(6-tert-butyl-3-methylphenol), and 1,3-bis(2-hydroxyethylthioethyl)-cyclohexane. Examplary suitable polythiol compounds include: aliphatic polythiol such as methanedithiol, 1,2-ethanedithiol, 1,1-propanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 2,2-propanedithiol, 1,6-hexanedithiol, 1,2,3-propanetrithiol, 1,1-cyclohexanedithiol, 1,2-cyclohexanedithiol, 2,2-dimethylpropane-1,3-dithiol, 3,4-dimethoxybutane-1,2-dithiol, 2-methylcyclohexane-2,3-dithiol, bicyclo[2,2,1]hepta-exo-cis-2,3-dithiol, 1,1-bis(mercaptomethyl)cyclohexane, thiomalic acid bis(2-mercaptoethylester), 2,3-dimercaptosuccinic acid (2-mercaptoethylester), 2,3-dimercapto-1-propanol(2-mercaptoacetate), 2,3-dimercapto-1-propanol(3-mercaptoacetate), diethylene glycol bis(2-mercaptoacetate), diethylene glycol bis(3-mercaptopropionate), 1,2-dimercaptopropyl methyl ether, 2,3-dimercaptopropyl methyl ether, 2,2-bis(mercaptomethyl)-1,3-propanedithiol, bis(2-mercaptoethyl) ether, ethylene glycol bis(2-mercaptoacetate), ethylene glycol bis(3-mercaptopropionate), trimethylolpropane tris(2-mercaptoacetate), trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane,; aromatic polythiol such as 1,2-dimercaptobenzene, 1,3-dimercaptobenzene, 1,4-dimercaptobenzene, 1,2-bis(mercaptomethyl)benzene, 1,3-bis(mercaptomethyl)benzene, 1,4-bis(mercaptomethyl)benzene, 1,2-bis(mercaptoethyl)benzene, 1,3-bis(mercaptoethyl)benzene, 1,4-bis(mercaptoethyl)benzene, 1,2-bis(mercaptomethyleneoxy)benzene, 1,3-bis(mercaptomethyleneoxy)benzene, 1,4-bis(mercaptomethyleneoxy)benzene, 1,2-bis(mercaptoethyleneoxy)benzene, 1,3-bis(mercaptoethyleneoxy)benzene, 1,4-bis(mercaptoethyleneoxy)benzene, 1,2,3-trimercaptobenzene, 1,2,4-trimercaptobenzene, 1,3,5-trimercaptobenzene, 1,2,3- tris(mercaptomethyl)benzene, 1,2,4-tris(mercaptomethyl)benzene, 1,3,5-tris(mercaptomethyl)benzene, 1,2,3-tris(mercaptoethyl)benzene, 1,2,4-tris(mercaptoethyl)benzene, 1,3,5-tris(mercaptoethyl)benzene, 1,2,3-tris(mercaptomethyleneoxy)benzene, 1,2,4-tris(mercaptomethyleneoxy)benzene, 1,3,5-tris(mercaptomethyleneoxy)benzene, 1,2,3-tris(mercaptoethyleneoxy)benzene, 1,2,4-tris(mercaptoethyleneoxy)benzene, 1,3,5-tris(mercaptoethyleneoxy)benzene, 1,2,3,4-tetramercaptobenzene, 1,2,3,5-tetramercaptobenzene, 1,2,4,5-tetramercaptobenzene, 1,2,3,4-tetrakis(mercaptomethyl)benzene, 1,2,3,5-tetrakis(mercaptomethyl)benzene, 1,2,4,5-tetraxis(mercaptomethyl)benzene, 1,2,3,4-tetrakis(mercaptoethyl)benzene, 1,2,3,5-tetrakis(mercaptoethyl)benzene, 1,2,4,5-tetrakis(mercaptoethyl)benzene, 1,2,3,4-tetrakis(mercaptomethyleneoxy)benzene, 1,2,3,5-tetrakis(mercaptomethyleneoxy)benzene, 1,2,4,5-tetrakis(mercaptomethyleneoxy)benzene, 1,2,3,4-tetrakis(mercaptoethyleneoxy)benzene, 1,2,3,5-tetrakis(mercaptoethyleneoxy)benzene, 1,2,4,5-tetrakis(mercaptoethyleneoxy)benzene, 2,2'-dimercaptobiphenyl, 4,4'-dimercaptobiphenyl, 4,4'-dimercaptobibenzyl, 2,5-toluenedithiol, 3,4-toluenedithiol, 1,4-naphthalenedithiol, 1,5-naphthalenedithiol, 2,6-naphthalenedithiol, 2,7-naphthalenedithiol, 2,4-dimethylbenzene-1,3-dithiol, 4,5-dimethylbensene-1,3-dithiol, 9,10-anthracenedimethanethiol, 1,3-di(p-methoxyphenyl)propane-2,2-dithiol, 1,3-diphenylpropane-2,2-dithiol, phenylmethane-1,1-dithiol, 2,4-di(p-mercaptophenyl)pentane, and the like; halogen-substituted (e.g. chloro-or bromo-substituted) aromatic polythiol such as 2,5-dichlorobenzene-1,3-dithiol, 1,3-di(p-chlorophenyl)propane-2,2-dithiol, 3,4,5-tribromo-1,2-dimercaptobenzene, 2,3,4,6-tetrachloro-1,5-bis(mercaptomethyl)benzene,; polythiol containing heterocyclic ring such as 2-methylamino-4,6-dithiol-sym-triazine, 2-ethylamino-4,6-dithiol-sym-triazine, 2-amino-4,6-dithiol-sym-triazine, 2-morpholino-4,6-dithiol-sym-triazine, 2-cyclohexylamino-4,6-dithiol-sym-triazine, 2-methoxy-4,6-dithiol-sym-triazine, 2-phenoxy-4,6-dithiol-sym-triazine, 2-thiobenzeneoxy-4,6-dithiol-sym-triazine, 2-thiobutyloxy-4,6-dithiol-sym-triazine,; aromatic polythiol containing sulfur atom other than mercapto group such as 1,2-bis(mercaptomethylthio)benzene, 1,3-bis(mercaptomethylthio)benzene, 1,4-bis(mercaptomethylthio)benzene, 1,2-bis(mercaptoethylthio)benzene, 1,3-bis(mercaptoethylthio)benzene, 1,4-bis(mercaptoethylthio)benzene, 1,2,3-tris(mercaptomethylthio)benzene, 1,2,4-tris(mercaptomethylthio)benzene, 1,3,5-tris(mercaptomethylthio)benzene, 1,2,3-tris(mercaptoethylthio)benzene, 1,2,4-tris(mercaptoethylthio)benzene, 1,3,5-tris(mercaptoethylthio)benzene, 1,2,3,4-tetrakis(mercaptomethylthio)benzene, 1,2,3,5-tetrakis(mercaptomethylthio)benzene, 1,2,4,5-tetrakis(mercaptomethylthio)benzene, 1,2,3,4-tetrakis(mercaptoethylthio)benzene, 1,2,3,5-tetrakis(mercaptoethylthio)benzene, 1,2,4,5-tetrakis(mercaptoethylthio)benzene, and the above-mentioned compounds with nuclear alkyl substituent(s),; aliphatic polythiol containing sulfur atom other than mercapto group such as bis(mercaptomethyl)sulfide, bis(mercaptoethyl)sulfide, bis(mercaptopropyl)sulfide, bis(mercaptomethylthio)methane, bis(2-mercaptoethylthio)methane, bis(3-mercaptopropylthio)methane, 1,2-bis(mercaptomethylthio)ethane, 1,2-(2-mercaptoethylthio)ethane, 1,2-(3-mercaptopropylthio)ethane, 1,3-bis(mercaptomethylthio)propane, 1,3-bis(2-mercaptoethylthio)propane, 1,3-bis(3-mercaptopropylthio)propane, 1,2,3-tris(mercaptomethylthio)propane, 1,2,3-tris(2-mercaptoethylthio)propane, 1,2,3-tris(3-mercaptopropylthio)propane, tetrakis(mercaptomethylthiomethyl)methane, tetrakis(2-mercaptoethylthiomethyl)methane, tetrakis(3-mercaptopropylthiomethyl)methane, bis(2,3-dimercaptopropyl)sulfide, 2,5-dimercapto-1,4-dithiane, 2,5-bis(mercaptomethyl)-1,4-dithiane, bis(mercaptomethyl)disulfide, bis(mercaptoethyl)disulfide, bis(mercaptopropyl)disulfide, and thioglycolic acid or mercaptopropionic acid esters of the above-mentioned compounds, hydroxymethylsulfide bis(2-mercaptoacetate), hydroxymethylsulfide bis(3-mercaptopropionate), hydroxyethylsulfide bis(2-mercaptoacetate), hydroxyethylsulfide bis(3-mercaptopropionate), hydroxypropylsulfide bis(2-mercaptoacetate), hydroxypropylsulfide bis(3-mercaptopropionate), hydroxymethyldisulfide bis(2-mercaptoacetate), hydroxymethyldisulfide bis(3-mercaptopropionate), hydroxyethyldisulfide bis(2-mercaptoacetate), hydroxyethyldisulfide bis(3-mercaptopropionate), hydroxypropyldisulfide bis(2-mercaptoacetate), hydroxypropyldisulfide bis(3-mercaptopropionate), 2-mercaptoethylether bis(2-mercaptoacetate), 2-mercaptoethylether bis(3-mercaptopropionate), 1,4-dithiane-2,5-diol bis(2-mercaptoacetate), 1,4-dithiane-2,5-diol bis(3-mercaptopropionate), thioglycolic acid bis(2-mercaptoethylester), thiodipropionic acid bis(2-mercaptoethylester), 4,4-thiodibutyric acid bis(2-mercaptoethylester), dithiodiglycolic acid bis(2-mercaptoethylester), dithiodipropionic acid bis(2-mercaptoethylester), 4,4-dithiodibutyric acid bis(2-mercaptoethylester), thiodiglycolic acid bis(2,3-dimercaptopropylester), thiodipropionic acid bis(2,3-dimercaptopropylester), dithioglycolic acid bis(2,3-dimercaptopropylester), dithiodipropionic acid (2,3-dimercaptopropylester),; and heterocyclic compounds containing sulfur atom other than mercapto group such as 3,4-thiophenedithiol, and 2,5-dimercapto-1,3,4-thiadiazole. Exemplary suitable hydroxythiol compounds include: 2-mercaptoethanol, 3-mercapto-1,2-propanediol, glycerine di(mercaptoacetate), 1-hydroxy-4-mercaptocyclohexane, 2,4-dimercaptophenol, 2-mercaptohydroquinone, 4-mercaptophenol, 3,4-dimercapto-2-propanol, 1,3-dimercapto-2-propanol, 2,3-dimercapto-1-propanol, 1,2-dimercapto-1,3-butanediol, pentaerythritol tris(3-mercaptopropionate), pentaerythritol mono(3-mercaptopropionate), pentaerythritol bis(3-mercaptopropionate), pentaerythritol tris(thioglycolate), pentaerythritol pentakis(3-mercaptopropionate), hydroxymethyl-tris(mercaptoethylthiomethyl)methane, 1-hydroxyethylthio-3-mercaptoethylthiobenzene, 4-hydroxy-4'-mercaptodiphenylsulfone, 2-(2-mercaptoethylthio)ethanol, dihydroxyethylsulfide mono(3-mercaptopropionate), dimercaptoethane mono(salicylate), and hydroxyethylthiomethyl-tris(mercaptoethylthio)methane. Further, there may be used halo-substituted active hydrogen compounds as mentioned above, such as the chloro-substituted or bromo-substituted compounds. The above-mentioned compounds may be used alone or in combination. The amount ratio of the iso(thio)cyanate compound to the active hydrogen compound may be such athat the functional group molar ratio,(NCO + NCS)/(OH + SH), is usually 0.5 - 3.0, preferably 0.5 - 1.5. Methods for molding urethane resins are usually casting polymerization method and reaction injection molding method. The casting polymerization method may be carried out, for example, by dissolving at least one sulfur-containing acid phosphoric ester in a mixture of at least one polyisocyanate compound and at least one active hydrogen compound, if necessary, defoaming the resulting mixture, then pouring into a mold, and polymerizing the poured mixture by raising the temperature gradually in the range of from -20 to 200°C, preferably from room temperature to 150°C, more preferably from 50° to 120°C for 0.5 - 72 hours. The reaction injection molding method may be carried out, for example, such that an active hydrogen compound and a polyisocyanate compound in which a sulfur-containing acid phosphoric ester is dissolved are separately fed into tanks for a high pressure mixing machine, mixed in the high pressure mixing machine under heating, and then injected into a mold to effect molding. Epoxy resins are resins which may be produced by polymerizing a material containing a monomer having an epoxy group. Epoxy resins used in the present invention are not particularly critical. Exemplary suitable monomers having an epoxy group include: (1) Amine type epoxy compounds Epoxy compounds having the group of the following formula, The epoxy compounds may be prepared, for example, by reacting a compound having an amino or amido group with an epihalohydrin such as epichlorohydrin, methylepichlorohydrin, and epibromohydrin. Examples of the epoxy compounds include N,N,N',N'-tetraglycidylaminodiphenylmethane, meta-N,N-diglycidylaminophenylglycidyl ether, and N,N,N',N'-tetraglycidyl terephthalamide. Exemplary suitable compounds having an amino group include: diaminodiphenylmethane, m-xylylenediamine, p-xylylenediamine, m-aminobenzylamine, p-aminobenzylamine, 1,3-bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, m-phenylenediamine, p-phenylenediamine, benzylamine, diaminodiphenylsulfone, diaminodiphenylether, diaminodiphenylsulfide, diaminodiphenylketone, naphthalenediamine, aniline, toluidine, m-aminophenol, p-aminophenol, and aminonaphthol. Exemplary suitable compounds having amido group include: phthalamide, isophthalamide, terephthalamide, benzamide, toluamide, p-hydroxybenzamide, and m-hydroxybenzamide. In the case of the compounds having amino group or amido group, when said compounds have hydroxyl, carboxyl, mercapto group capable of reacting with an epihalohydrin other than the amino or amido group, a part or all of the group(s) capable of reacting with an epihalohydrin may react with a epihalohydrin and as a result, the compounds may have an epoxy substituent. (2) Phenol type epoxy compounds This type of compounds may be prepared from a phenol type compound and an epihalohydrin. Examples of this type of compounds are bisphenol A diglycidyl ether and Epitohto YDCN-220 (trade name, supplied by Tohto Kasei). Exemplary suitable phenol type compounds include: hydroquinone, catechol, resorcin, bisphenol A, bisphenol F, bisphenol sulfone, brominated bisphenol A, novolac, cresol novolac, tetraphenylethane, and triphenylethane. (3) Alcohol type epoxy compounds The compounds may be prepared from an alcohol type compound and an epihalohydrin and include trimethylolpropane triglycidyl ether, and neopentylglycol diglycidyl ether. Exemplary suitable alcohol type compounds include: polyhydric alcohol such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, dibromoneopentyl glycol, trimethylolpropane, glycerin, pentaerythritol, polycaprolactone, polytetramethylene ether glycol, polybutadiene glycol, hydrogenated bisphenol A, cyclohexanedimethanol, bisphenol A-ethylene oxide adducts, bisphenol A-propylene oxide adducts, and polyester polyols producible from the polyhydric alcohols and polybasic carboxylic acids. (4) Epoxidized unsaturated compounds There may be mentioned epoxidized unsaturated compounds such as cyclopentadiene epoxide, epoxidized soybean oil, epoxidized polybutadiene, vinylcyclohexene epoxide, ERL - 4221, ERL - 4234 and ERL - 4299 (trade name, supplied by Union Carbide Co.). (5) Glycidyl ester type epoxy compounds The compounds may be produced from a carboxylic acid and a epihalohydrin. Examples thereof are tetrahydrophthalic acid diglycidyl ester. Exemplary suitable carboxylic acids include: polybasic carboxylic acid such as adipic acid, sebacic acid, dodecane dicarboxylic acid, dimer acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, fat acid, nadic acid, maleic acid, fumaric acid, trimellitic acid, benzene tetracarboxylic acid, butane tetracarboxylic acid benzophenone tetracarboxylic acid, and 5-(2,5-dioxotetrahydrofuryl)-3-methyl-cyclohexene-1,2-dicarboxylic acid. (6) Urethane type epoxy compounds The compounds may be prepared from polyhydric alcohols as enumerated in (3) above and diisocyanates, glycidols, or 3-hydroxypropylenesulfides. Exemplary suitable diisocyanates include: tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, and naphthalene diisocyanate. (7) Alicyclic epoxy compounds Examples of the alicyclic epoxy compounds include: 3,4-epoxycyclohexyl-3,4-epoxycyclohexane carboxylate, vinylcyclohexene dioxide, 2-(3,4-epoxycyclohexyl)-5,5-spiro-3,4-epoxy)cyclohexane-meta-dioxane, and bis(3,4-epoxycyclohexyl)adipate. (8) Epoxy compounds having unsaturated double bond Examples of the compounds include: glycidyl methacrylate, glycidyl acrylate, allylglycidyl ether, methacrylglycidyl ether, 4-(glycidyloxy)styrene, α-methyl-4-(glycidyloxy)styrene, 4-vinylbenzoic acid glycidyl ester, 4-isopropenylbenzoic acid glycidyl ester, 2,2'-divinylbisphenol A glycidyl ether, 2,2'-dipropenylbisphenol A glycidyl ether, bis(2-vinylbenzoic acid glycidyl ester)methane, bis(2-propenylbenzoic acid glycidylester)methane, epoxysuccinic acid diallyl ester, and 3,4-epoxymethacryloyloxytricyclo[5,2,1,0 2,6 ] decane,. These epoxy compounds may have a halogen substituent such as chlorine, and bromine, and may have episulfide group in place of the epoxy group. Further, these epoxy compounds may be polymerized alone or in combination. Furthermore, the epoxy compounds may be polymerized together with known compounds which are generally classified into epoxy resin curing agents, such as alcohols, phenols, thiols, carboxylic acids, carboxylic acid anhydrides, amines, amides, sulfonic acids, and isocyanates. Exemplary suitable curing agents include: alcohols such as ethylene glycol, trimethylolpropane,; phenols such as bisphenol A, tetrabromobisphenol A, bis(hydroxyethyl)sulfide, bis[4-(hydroxyethoxy)phenyl]sulfide,; thiols such as ethandithiol, trithioglycerine, pentaerythritol tetrakis(thioglycolate), bis(mercaptoethyl)sulfide,; carboxylic acids such as maleic acid, succinic acid, thiodiglycolic acid, 3,3'-thiodipropionic acid, phthalic acid, p-phenylenedithiodiglycolic acid,; carboxylic acid anhydrides such as phthalic anhydride, hexahydrophthalic anhydride, trimellitic anhydride, dodecylsuccinic anhydride, tetrabromophthalic anhydride, adduct of methylcyclopentadiene and maleic anhydride,; amines such as diethylene triamine, triethylene tetramine, m-phenylene diamine, diaminodiphenylamine, diaminodiphenylsulfone,; polyamides such as condensates of an aliphatic acid such as fatty acids, dimer acid, trimer acid and the like with an aliphatic polyamine; sulfonic acids such as m-benzenedisulfonic acid, bis(4-sulfobenzene)disulfide,; isocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, xylylenediisocyanate, hexamethylene diisocyanate, isophorone diisocyanate,; and curing agents having two or more functional groups such as 2-mercaptoethanol, thiogylcolic acid, glycolic acid, 3-(hydroxysulfoxy) propionic acid, 4-aminobenzenesulfonic acid, 4-mercaptobenzenesulfonic acid, 4-aminobenzenethiophenol, and 2-mercaptoethylamine. In addition, there may be mentioned complex of boron trifluoride and ethylamine, and salts such as diazonium salts, iodonium salts, bromonium salts, sulfinium salts of boron tetrafluoride, and phosphorus hexafluoride. These epoxy resin curing agents may be used alone or in combination. When epoxy compounds having an unsaturated double bond are used, there may be effected a copolymerization with vinyl monomers such as acrylic ester, styrene, diallyl phthalate, diethylene glycol methacrylate, and diethylene glycol bisallyl carbonate. When an epoxy resin curing agent is used, the functional group molar ratio, i.e. (reactive group of the curing agent)/(epoxy group of the epoxy compound), is preferably in the range of 0.1 - 2.0. Epoxy resin molding is usually carried out by casting polymerization. As the method for polymerization, there may be heat polymerization and photo-polymerization and the method is appropriately selected depending on the epoxy resin to be used. A general heat polymerization may be carried out by adding a sulfur-containing acid phosphoric ester internal release agent and a polymerization catalyst to an epoxy monomer mixture, pouring the resulting mixture into a mold composed of a resin gasket and metal or glass mold members and heating at 10 - 150°C for 2 - 30 hours. A polymerization catalyst for heat polymerization may be appropriately selected from known polymerization catalysts such as tertiary amines, salts thereof, quaternary ammonium salts, imidazoles, tin compounds, peroxides, carboxylic acid metal salts, phosphines, tetraphenyl boron salts depending on the type of the epoxy resin to be used. Photo-polymerization may be carried out by adding a sulfur-containing acid phosphoric ester internal release agent, a known polymrization catalyst such as peroxides, onium salts of Lewis acid anion, silanol derivative aluminum chelates, if necessary, known additives such as photo-polymerization initiating auxiliary, sensitizer and the like to an epoxy monomer mixture, pouring the resulting mixture to a mold composed of a resin gasket and glass mold members, and irradiating the poured mixture with a light of 180 - 700 nm for 0.5 - 15 min. In such casting polymerization, if necessary, there may be added known additives such as ultraviolet light absorber, antioxidant, dye, and fillers. Polyolefin resins are resins producible by radical polymerization of monomers having an unsaturated double bond. Exemplary suitable monomers having an unsaturated double bond include: aliphatic olefin compound such as ethylene, propylene, vinyl chloride,; aromatic vinyl compounds such as styrene, α-methylstyrene, p-methylthiostyrene, m-divinylbenzene, 3,3'-divinylbiphenyl, 2-(4-vinylbenzylthio)ethanol, isopropenylnaphthalene, 1,4-bis(4-vinylbenzylthio)benzene, 1,2-bis(4-vinylbenzylthio)ethane, 2-(p-vinylphenylthio)benzothiazole, cinnamic acid p-vinylbenzyl ester,; acrylic acid ester compounds such as methyl acrylate, methyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, triphenylmethyl methacrylate, tribromophenyl methacrylate, isonorbornyl methacrylate, 2-methacryloyloxymethylthiophene, 2-bicyclo[2.2.1]heptane methacrylate, ethylene glycol dimethacrylate, 2,2-bis(4-methacryloxyphenyl)propane, 1,1,1-trimethylolpropane triacrylate, N,N',N''-isocyanurtriacrylate, bis(2-methacryloylthioethyl)sulfide, 2,5-di(methacryloyloxy)-1,4-dithione, bis(acryloxymethyl)tricyclo[5.2.1.0 2,6 ]decane, S-methylthiomethacrylate, 1,2-bis(methacryloylthio)ethane, bis(methacryloylthioethyl)sulfide, 4,4'-dimercaptodiphenylsulfide dimethacrylate,; unsaturated nitrile compound such as acrylonitrile, methacrylonitrile, cinnamonitrile; acrylamide compound such as acrylamide, methacrylamide,; allyl ester compound such as diallyl phthalate, diallyl maleate, diallyl fumarate, allyl cinnamate, allyl benzoate,; allyl ether compound such as diallyl ether, bis(allyloxy)ethane, 2,2-bis(4-allyloxyphenyl)propane, 2,2-bis(4-allyloxyethoxyphenyl)propane, 1,4-bis(allylthio)benzene, diallylidene pentaerythritol,; allyl carbonate compound such as diethylene glycol bisallyl carbonate, β-thiodiglycol bisallyl carbonate, 2,2-bis[4-(2-allyloxycarbonyloxy)ethoxy-3,5-dibromophenyl]propane,; and maleimide compound such as cyclohexylmaleimide, n-octylmaleimide, phenylmaleimide, chlorophenylmaleimide, and N,N'-(4,4'-diphenylmethane)bismaleimide. These compounds having an unsaturated double bond may be polymerized alone or in combination. In usual, thermoplastic polyolefin resins are molded by injection molding, and thermosetting polyolefin resins are molded by casting polymerization. Conditions of casting polymerization are optionally selected depending on the monomers to be used. In usual , a sulfur-containing acid phosphoric ester and a radical polymerization initiator are added to the monomers, and if necessary, a defoaming treatment is effected under reduced pressure, and then the mixture is poured into a mold. Then, a radical polymerization is carried out by means of heat, microwave, infrared ray, or ultraviolet ray. Exemplary suitable radical polymerization initiators usable for polymerization by means of heat, microwave or infrared ray include: azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobisisovaleronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile); ketone peroxides such as methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, cyclohexanone peroxide, acetylacetone peroxide,; diacyl peroxides such as isobutyryl peroxide, 2,4-dichlorobenzoyl peroxide, o-methylbenzoyl peroxide, lauroyl peroxide, p-chlorobenzoyl peroxide,; hydroperoxides such as 2,4,4-trimethylpentyl-2-hydroperoxide, diisopropylbenzene peroxide cumene hydroperoxide, t-butylperoxide,; dialkyl peroxides such as dicumyl peroxide, t-butylcumyl peroxide, di-t-butyl peroxide, tris(t-butyl peroxide)triazine,; peroxyketals such as 1,1-di-t-butylperoxycyclohexane, 2,2-di-(t-butylperoxy)butane,; alkyl peresters such ss t-butylperoxypivalate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxyacetate, t-butylperoxybenzoate, di-t-butylperoxytrimethyladipate,; and percarbonates such as diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, and t-butyl peroxyisopropylcarbonate. Exemplary suitalbe radical polymerization initiators for polymerization by means of ultraviolet ray include: carbonyl compounds such as acetophene, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 4'-isopropyl-2-hydroxy-2-methylpropiophenone, 2-hydroxy-2-methylpropiophenone, 4,4'-bis(diethylamino)benzophenone, benzophenone, methyl(o-benzoyl)benzoate, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-benzoyl)oxime, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, benzoin octyl ether, benzil, benzil dimethylketal, benzil diethylketal, and diacetyl; anthraquinone or thioxanthone derivatives such as methylanthraquinone, chloroanthraquinone, chlorothioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, and the like; and sulfur compounds such as diphenyl disulfide, and dithiocarbamate. The amount of the radical polymerization initiator may be optionally selected depending on type of radical polymerization initiator, type of monomers to be used, and the like. It is usually 0.001 - 10 mol %, preferably 0.1 - 3 mol % based on the monomer to be used. When the amount of the radical polymerization initiator is less than 0.001 mol %, the polymerization does not substantially proceed. When the amount exceeds 10 mol %, such large amount is not economical, and moreover, sometimes foaming occurs during polymerization or the molecular weight of the resulting cured product is markedly small. In the case of casting polymerization, the monomer composition may be directly polymerized and cured, or may be polymerized and cured after preliminary polymerization, so as to adjust the viscosity or decrease shrinkage upon polymerization, depending on the purpose. When transparency of the molded product is not particularly required, various fillers may be compounded, if necessary. As the fillers, there may be mentioned glass fibers, alumina fibers, carbon fibers, aramid fibers and the like, and powder-like fillers such as silica, almina, barium sulfate, and titanium oxide. In addition, there may be used flame retardants, dyes, and pigments. Polymerization temperature and polymerization time for casting polymerization can not be unanimously determined since these factors vary depending on types of radical polymerization initiators used and amounts thereof, but the polymerization temperature is usually 0 - 150°C, preferably 20 - 120°C. In the case of heat polymerization, the polymerization temperature is gradually raised usually over 10 - 30 hours, and in the case of polymerization using ultraviolet ray, the irradiation is effected for 0.5 - 10 min. to complete the polymerization. Among polyolefin resins, as an example of the resins which can be injection-molded, thermoplastic acrylic resins can be shown, and the acrylic resins may be homopolymers of an acrylic monomer, copolymers of acrylic monomers, or copolymers of an acrylic monomer and other olefin monomer. Examples of acrylic monomers may be acrylic acid compounds and methacrylic acid compounds. Exemplary suitable acrylic acid compounds include: acrylic acid alkyl ester such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate,; acrylic acid cycloalkyl ester such as cyclohexyl acrylate, bornyl acrylate, menthyl acrylate, adamantyl acrylate, tricyclodecyl acrylate,; acrylic acid aromatic ester such as phenyl acrylate, benzyl acrylate, naphthyl acrylate,; acrylic acid halo-substituted aromatic ester such as fluorophenyl acrylate, chlorophenyl acrylate,; acrylic acid halogenated alkyl ester such as fluoromethyl acrylate, chloroethyl acrylate, bromoethyl acrylate,; acrylic acid hydroxyalkyl ester; and thioacrylic acid S-alkyl ester such as S-methyl thioacrylate. Exemplary suitable methacrylic acid compounds include: methacrylic acid alkyl ester such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate,; methacrylic acid cycloalkyl ester such as cyclohexyl methacrylate, bornyl methacrylate, mentyl methacrylate, adamantyl methacrylate, tricyclodecyl methacrylate,; methacrylic acid aromatic ester such as phenyl methacrylate, benzyl methacrylate, naphthyl methacrylate,; methacrylic acid halo-substituted aromatic ester such as fluorophenyl methacrylate, chlorophenyl methacrylate,; methacrylic acid halogenated alkyl ester such as fluoromethyl methacrylate, chloroethyl methacrylate, bromoethyl methacrylate,; hydroxyalkyl methacrylate; and thiomethacrylic acid S-alkyl ester such as S-methyl thiomethacrylate. As other olifin monomers there may be mentioned the following compounds. As vinyl compounds, there may be mentioned: aromatic vinyl compounds such as styrene, α-methylstyrene, α-ethylstyrene, fluorostyrene, chlorostyrene, bromostyrene, methylstyrene, methylthiostyrene,; and cyanated vinyl compounds such as acrylonitrile, and methacrylonitrile. As unsaturated dibasic acids and derivatives thereof, there may be mentioned N-substituted maleimide such as N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-octylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, dipropyl maleate, dibutyl maleate, dipropyl fumarate, dibutyl fumarate, and maleic anhydride,. As unsaturated fatty acids and derivatives thereof, there may be mentioned acrylamide, N,N-dimethylacrylamide,. Injection molding conditions may be optionally selected depending on the type of the resin used. In general, a mixture of an acrylic resin and a sulfur-containing acid phosphoric ester is melted at a resin temperature of 220° - 320°C and injected into a mold at 50 - 150°C with an extruder, and after completion of the molding, the molded product is released. Further, according to the present invention, known additives such as antioxidant, ultraviolet ray absorber, photo-stabilizer, colorant, fillers may be used depending on the purpose. Polyene-polythiol resins are resins producible by addition polymerization of a polyene compound having at least two unsaturated double bonds in a molecule and a polythiol compound having at least two mercapto groups in a molecule. Exemplary suitable polyene compounds for the polyene-polythiol resins include: aromatic vinyl compound such as m-divinylbenzene, 3,3'-divinylbiphenyl, 1,4-bis(4-vinylbenzylthio)benzene, 1,2-bis(4-vinylbenzylthio)ethane,; acrylic acid ester compound such as ethylene glycol dimethacrylate, ethylene glycol diacrylate, 2,2-bis(4-methacryloxyphenyl)propane, bis(2-methacryloylthioethyl)sulfide, 2,5-di(methacryloyloxy)-1,4-dithiane, 1,2-bis(acryloylthio)ethane, bis(4-methacryloylthiophenyl)sulfide; allyl ester compound such as diallyl phthalate, diallyl maleate, diallyl fumarate, allyl cinnamate; allyl ether compound such as diallyl ether, diallyl sulfide, bis(allyloxy)ethane, 2,2-bis(4-allyloxyphenyl)propane, 2,2-bis(4-allyloxyethoxyphenyl)propane, 1,4-bis(allylthio)benzene, diallylidene pentaerythritol, diallylidene-2,2,6,6-tetramethylol cyclohexane; and allyl carbonate compound such as diethylene glycol bis(allyl carbonate), β-thiodiglycol bisallyl carbonate, and 2,2-bis[4-(allyloxycarbonyloxy)phenyl]propane. These polyene compounds may be used alone or in combination. Examples of polythiol compounds used for polyenepolythiol resins may be as mentioned below. Aliphatic polythiol such as methanedithiol, 1,2-ethanedithiol, 1,1-propanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 2,2-propanedithiol, 1,6-hexanedithiol, 1,2,3-propanetrithiol, 1,1-cyclohexanedithiol, 1,2-cyclohexanedithiol, 2,2-dimethylpropane-1,3-dithiol, 3,4-dimethoxybutane-1,2-dithiol, 2-methylcyclohexane-2,3-dithiol, bicyclo[2.2.1]hepta-exo-cis-2,3-dithiol, 1,1-bis(mercaptomethyl)cyclohexane, thiomalic acid bis(2-mercaptoethylester), 2,3-dimercaptosuccinic acid (2-mercaptoethylester), 2,3-dimercapto-1-propanol(2-mercaptoacetate), 2,3-dimercapto-1-propanol(3-mercaptoacetate), diethylene glycol bis(2-mercaptoacetate), diethylene glycol bis(3-mercaptopropionate), 1,2-dimercaptopropyl methyl ether, 2,3-dimercaptopropyl methyl ether, 2,2-bis(mercaptomethyl)-1,3-propanedithiol, bis(2-mercaptoethyl) ether, ethylene glycol bis(2-mercaptoacetate), ethylene glycol bis(3-mercaptopropionate), trimethylolpropane bis(3-mercaptopropionate), pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), bis(mercaptomethyl)sulfide, bis(mercaptoethyl)sulfide, bis(mercaptopropyl)sulfide, bis(mercaptomethylthio)methane, bis(2-mercaptoethylthio)methane, bis(3-mercaptopropylthio)methane, 1,2-bis(mercaptomethylthio)ethane, 1,2-bis(mercaptoethylthio)ethane, 1,2-bis(mercaptopropylthio)ethane, 1,3-bis(mercaptomethylthio)propane, 1,3-bis(2-mercaptoethylthio)propane, 1,3-bis(3-mercaptopropylthio)propane, 1,2,3-tris(mercaptomethylthio)propane, 1,2,3-tris(2-mercaptoethylthio)propane, 1,2,3-tris(3-mercaptopropylthio)propane, tetrakis(mercaptomethylthiomethyl)methane, tetrakis(2-mercaptoethylthiomethyl)methane, tetrakis(3-mercaptopropylthiomethyl)methane, bis(2,3-dimercaptopropyl)sulfide, 2,5-dimercapto-1,4-dithiane, 2,5-bis(mercaptomethyl)-1,4-dithiane, bis(mercaptomethyl)disulfide, bis(mercaptoethyl)disulfide, bis(mercaptopropyl)disulfide, and thioglycolic acid or mercaptopropionic acid esters of the above-mentioned compounds, hydroxymethylsulfide bis(2-mercaptoacetate), hydroxymethylsulfide bis(3-mercaptopropionate), hydroxyethylsulfide bis(2-mercaptoacetate), hydroxyethylsulfide bis(3-mercaptopropionate), hydroxypropylsulfide bis(2-mercaptoacetate), hydroxypropylsulfide bis(3-mercaptopropionate), hydroxymethyldisulfide bis(2-mercaptoacetate), hydroxymethyldisulfide bis(3-mercaptopropionate), hydroxyethyldisulfide bis(2-mercaptoacetate), hydroxyethyldisulfide bis(3-mercaptopropionate), hydroxypropyldisulfide bis(2-mercaptoacetate), hydroxypropyldisulfide bis(3-mercaptopropionate), 2-mercaptoethylether bis(2-mercaptoacetate), 2-mercaptoethylether bis(3-mercaptopropionate), 1,4-dithiane-2,5-diol bis(2-mercaptoacetate), 1,4-dithiane-2,5-diol bis(3-mercaptopropionate), thioglycolic acid bis(2-mercaptoethylester), thiodipropionic acid bis(2-mercaptoethylester), 4,4-thiodibutyric acid bis(2-mercaptoethylester), dithiodiglycolic acid bis(2-mercaptoethylester), dithiodipropionic acid bis(2-mercaptoethylester), 4,4-dithiodibutyric acid bis(2-mercaptoethylester), thiodiglycolic acid bis(2,3-dimercaptopropylester), thiodipropionic acid bis(2,3-dimercaptopropylester), dithioglycolic acid bis(2,3-dimercaptopropylester), dithiodipropionic acid (2,3-dimercaptopropylester); aromatic polythiol such as 1,2-dimercaptobenzene, 1,3-dimercaptobenzene, 1,4-dimercaptobenzene, 1,2-bis(mercaptomethyl)benzene, 1,3-bis(mercaptomethyl)benzene, 1,4-bis(mercaptomethyl)benzene, 1,2-bis(mercaptoethyl)benzene, 1,3-bis(mercaptoethyl)benzene, 1,4-bis(mercaptoethyl)benzene, 1,2-bis(mercaptomethyleneoxy)benzene, 1,3-bis(mercaptomethyleneoxy)benzene, 1,4-bis(mercaptomethyleneoxy)benzene, 1,2-bis(mercaptoethyleneoxy)benzene, 1,3-bis(mercaptoethyleneoxy)benzene, 1,4-bis(mercaptoethyleneoxy)benzene, 1,2,3-trimercaptobenzene, 1,2,4-trimercaptobenzene, 1,3,5-trimercaptobenzene, 1,2,3- tris(mercaptomethyl)benzene, 1,2,4-tris(mercaptomethyl)benzene, 1,3,5-tris(mercaptomethyl)benzene, 1,2,3-tris(mercaptoethyl)benzene, 1,2,4-tris(mercaptoethyl)benzene, 1,3,5-tris(mercaptoethyl)benzene, 1,2,3-tris(mercaptomethyleneoxy)benzene, 1,2,4-tris(mercaptomethyleneoxy)benzene, 1,3,5-tris(mercaptomethyleneoxy)benzene, 1,2,3-tris(mercaptoethyleneoxy)benzene, 1,2,4-tris(mercaptoethyleneoxy)benzene, 1,3,5-tris(mercaptoethyleneoxy)benzene, 1,2,3,4-tetramercaptobenzene, 1,2,3,5-tetramercaptobenzene, 1,2,4,5-tetramercaptobenzene, 1,2,3,4-tetrakis(mercaptomethyl)benzene, 1,2,3,5-tetrakis(mercaptomethyl)benzene, 1,2,4,5-tetrakis(mercaptomethyl)benzene, 1,2,3,4-tetrakis(mercaptoethyl)benzene, 1,2,3,5-tetrakis(mercaptoethyl)benzene, 1,2,4,5-tetrakis(mercaptoethyl)benzene, 1,2,3,4-tetrakis(mercaptomethyleneoxy)benzene, 1,2,3,5-tetrakis(mercaptomethyleneoxy)benzene, 1,2,4,5-tetrakis(mercaptomethyleneoxy)benzene, 1,2,3,4-tetrakis(mercaptoethyleneoxy)benzene, 1,2,3,5-tetrakis(mercaptoethyleneoxy)benzene, 1,2,4,5-tetrakis(mercaptoethyleneoxy)benzene, 2,2'-dimercaptobiphenyl, 4,4'-dimercaptobiphenyl, 4,4'-dimercaptobibenzyl, 2,5-toluenedithiol, 3,4-toluenedithiol, 1,4-naphthalenedithiol, 1,5-naphthalenedithiol, 2,6-naphthalenedithiol, 2,7-naphthalenedithiol, 2,4-dimethylbenzene-1,3-dithiol, 4,5-dimethylbenzene-1,3-dithiol, 9,10-anthracenedimethanethiol, 1,3-di(p-methoxyphenyl)propane-2,2-dithiol, 1,3-diphenylpropane-2,2-dithiol, phenylmethane-1,1-dithiol, 2,4-di(p-mercaptophenyl)pentane, 1,2-bis(mercaptomethylthio)benzene, 1,3-bis(mercaptomethylthio)benzene, 1,4-bis(mercaptomethylthio)benzene, 1,2-bis(mercaptoethylthio)benzene, 1,3-bis(mervaptoethylthio)benzene, 1,4-bis(mercaptoethylthio)benzene, 1,2,3-tris(mercaptomethylthio)benzene, 1,2,4-tris(mercaptomethylthio)benzene, 1,3,5-tris(mercaptomethylthio)benzene, 1,2,3-tris(mercaptoethylthio)benzene, 1,2,4-tris(mercaptoethylthio)benzene, 1,3,5-tris(mercaptoethylthio)benzene, 1,2,3,4-tetrakis(mercaptomethylthio)benzene, 1,2,3,5-tetrakis(mercaptomethylthio)benzene, 1,2,4,5-tetrakis(mercaptomethylthio)benzene, 1,2,3,4-tetrakis(mercaptoethylthio)benzene, 1,2,3,5-tetrakis(mercaptoethylthio)benzene, 1,2,4,5-tetrakis(mercaptoethylthio)benzene, and the above-mentioned compounds which are nuclear-alkylated; and heterocyclic polythiol compound such as 2-methylamino-4,6-dithiol-sym-triazine, 2-ethylamino-4,6-dithiol-sym-triazine, 2-amino-4,6-dithiol-sym-triazine, 2-morpholino-4,6-dithiol-sym-triazine, 2-cyclohexylamino-4,6-dithiol-sym-triazine, 2-methoxy-4,6-dithiol-sym-triazine, 2-phenoxy-4,6-dithiol-sym-triazine, 2-thiobenzeneoxy-4,6-dithiol-sym-triazine, 3,4-thiophenedithiol, Bismuthiol, 2,5-dimercapto-1,3,4-thiadiazole. Further, these polythiol compounds may have substituents, for example, halogen such as chloro, bromo, and the like, hydroxyl, amino. These polythiol compounds may be used alone or in combination. The mixing ratio of the polythiol compound to the polyene compound is such that the functional group molar ratio, (mercapto group / double bond), is preferably 0.001 - 1.2, more preferably 0.01 - 1.0. When the ratio is larger than 1.2, hardness of the resulting resin is not sufficient. When the ratio is smaller than 0.001, various good physical properties such as high refractive index, low water absorption can not be sufficiently exhibited. For purposes of controlling the crosslinking density, monoolefin compounds such as methyl acrylate, styrene and the like or monothiol compounds such as octyl mercaptane, dodecyl mercaptane may be added to a mixture of polyene compounds and polythiol compounds. Casting polymerization conditions may be optionally selected depending on the monomers to be used. In usual, a sulfur-containing acid phosphoric ester and a radical polymerization initiator are added to a monomer to be used, if necessary, the resulting mixture is defoamed under reduced pressure, and poured into a mold. Then, a radical polymerization is carried out by means of heat, microwave, infrared ray, or ultraviolet ray. Exemplary suitable radical polymerization initiators usable for polymerization by means of heat, microwave or infrared ray include: azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobisisovaleronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile); ketone peroxides such as methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, cyclohexanone peroxide, acetylacetone peroxide; diacyl peroxides such as isobutyryl peroxide, 2,4-dichlorobenzoyl peroxide, o-methylbenzoyl peroxide, lauroyl peroxide, p-chlorobenzoyl peroxide; hydroperoxides such as 2,4,4-trimethylpentyl-2-hydroperoxide, diisopropylbenzene peroxide cumene hydroperoxide, t-butylperoxide,; dialkyl peroxides such as dicumyl peroxide, t-butylcumyl peroxide, di-t-butyl peroxide, tris(t-butyl peroxide)triazine,; peroxyketals such as 1,1-di-t-butylperoxycyclohexane, 2,2-di-(t-butylperoxy)butane; alkyl peresters such as t-butylperoxypivalate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxyacetate, t-butylperoxybenzoate, di-t-butylperoxytrimethyladipate; and percarbonates such as diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, t-butyl peroxyisopropylcarbonate. Exemplary suitalbe radical polymerization initiators for polymerization by means of ultraviolet ray include: carbonyl compounds such as acetophene, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 4'-isopropyl-2-hydroxy-2-methylpropiophenone, 2-hydroxy-2-methylpropiophenone, 4,4'-bis(diethylamino)benzophenone, benzophenone, methyl(o-benzoyl)benzoate, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-benzoyl)oxime, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, benzoin octyl ether, benzil, benzil dimethylketal, benzil diethylketal, diacetyl; anthraquinone or thioxanthone derivatives such as methylanthraquinone, chloroanthraquinone, chlorothioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone,; and sulfur compounds such as diphenyl disulfide, dithiocarbamate. The amount of the radical polymerization initiator may be optionally selected depending on type of radical polymerization initiator, type of monomers to be used, and the like. It is usually 0.001 - 10 mol %, preferably 0.1 - 3 mol % based on the monomer to be used. When the amount of the radical polymerization initiator is less than 0.001 mol %, the polymerization does not substantially proceed. When the amount exceeds 10 mol %, such large amount is not economical, and moreover, sometimes foaming occurs during polymerization or the molecular weight of the resulting cured product is markedly small. In the case of casting polymerization, the monomer composition may be directly polymerized and cured, or may be polymerized and cured after preliminary polymerization, so as to adjust the viscosity or decrease shrinkage upon polymerization, depending on the purpose. When transparency of the molded product is not particularly required, various fillers may be compounded, if necessary. As the fillers, there may be mentioned glass fibers, alumina fibers, carbon fibers, aramid fibers and the like, and powder-like fillers such as silica, almina, barium sulfate, and titanium oxide. In addition, there may be used flame retardants, dyes, and pigments. Polymerization temperature and polymerization time for casting polymerization can not be unanimously determined since these factors vary depending on types of radical polymerization initiators used and amounts thereof, but the polymerization temperature is usually 0 - 150°C, preferably 20 - 120°C. In the case of heat polymerization, the polymerization temperature is gradually raised usually over 10 - 30 hours, and in the case of polymerization using ultraviolet ray, the irradiation is effected for 0.5 - 10 min. to complete the polymerization. As polycarbonate resins, there may be mentioned homopolymers or copolymers producible by the reaction of dihydric phenols with carbonylation agents such as phosgene, and diphenylcarbonate. The polymers may be branched or have long chain alkyl groups at the ends. The average molecular weight may be about 12,000 -30,000. Further, the following modified polycarbonate resins may be used: modified polycarbonate resins (produced by using a comonomer, a bisphenol having a carbon-carbon unsaturated double bond or vinylphenol as an end terminator) grafted with styrene, polycarbonate resins having partly ester bonds prepared by using terephthalic acid chloride or isophthalic acid chloride as a part of phosgene, and modified polystyrene graft-polymerized with polycarbonate resins (phenolic hydroxyl groups have been introduced into the polystyrene as comonomers). The present invention may be effectively used for reinforced resin compositions composed of polycarbonate resins reinforced with glass fibers, carbon fibers or the like, and resin compositions composed of polycarbonate resin and ABS resin, polyester resin such as polyethylene terephthalate, or PMMA resin. As divalent phenols, there may be mentioned: 2,2-bis(4-hydroxyphenyl)propane, bis(4-hydrophenyl)methane, 1,2-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)-1-phenylmethane, 1,1-bis(4-hydroxyphenyl-1,1-diphenyl)methane, 1,1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)sulfide, and bis(4-hydroxyphenyl)sulfone. The phenyl groups may have lower alkyl group or halogen atom as a substituent. According to the present invention, there may be added known antioxidant, ultraviolet ray absorber, colorant, or fillers, depending on the purposes. As polyester resins, there may be mentioned thermosetting polyester resins such as alkyd resins, and unsaturated polyester resins, and thermoplastic polyester resins such as polyethylene terephthalate. Polyester resins are producible by condensing polybasic acids with polyols. Exemplary suitable polybasic acids include: phthalic anhydride, isophthalic acid, maleic acid, fumaric acid, sebacic acid, adipic acid, citric acid, tartaric acid, malic acid, diphenic acid, 1,8-naphthalic acid, and terephthalic acid. Exemplary suitable polyols include: glycerine, pentaerythritol, ethylene glycol, diethylene glycol, and trimethylolpropane,. Depending on the purposes, there may be added known antioxidant, ultraviolet ray absorber, colorant, and fillers. According to the present invention, the internal release agent, i.e. the particular sulfur-containing acid phosphoric ester, can improve releasability of molded products in resin molding procedures and in addition, sufficiently satisfy the transparency of the molded product when a transparent resin is molded. The particular sulfur-containing acid phosphoric ester has a good compatibility with various resins or monomers, and therefore, is easily used as an internal release agent. The present invention is particularly useful for molding optical products such as plastic lens and the like which requires surface accuracy and transparency. The method for molding resins using the particular sulfur-containing acid phosphoric ester as an internal release agent according to the present invention can improve the releasability between a resin molded product and a mold, and the resulting molded product is substantially free from strains caused by stress upon releasing, and the resin does not dirty the surface of the mold. In addition, in the case of molding a transparent resin, substantially the transparency is not adversely affected. The present invention is now more particularly described with reference to the following examples which are for the purpose of illustration only. In Examples 1 - 38 and Comparative Examples 1 - 76, the urethane resins were molded into a flat plate of 70 mm in diameter and 9 mm in thickness. Evaluation of releasability was made by inserting a Teflon wedge between the molded product and the mold, and when released easily, it was designated as "○", when released though there was some resistance, it was designated as "▵", and when not released, it was designated as "X". The turbidity was determined by measuring the haze value of a flat plate urethane resin of 9 mm thick by using Degital Haze Computer HGM-2DP manufactured by Suga Shikenki K.K. according to JIS K 7105, 6.4 . EXAMPLES 1 - 38 A mixture of a polyisocyanate compound, an active hydrogen compound, and a sulfur-containing acid phosphoric ester as shown in Table 1 was poured into a glass mold and the temperature was gradually raised from 25°C to 120°C over 48 hours to carry out a casting molding. Table 1 shows releasability and haze value of the urethane resin flat plate after polymerization. In each example, releasing was easily effected and the urethane flat plate had a small haze and was good. COMPARATIVE EXAMPLES 1 - 76 Each of the procedures of Examples 1 - 38 was repeated except that a known internal release agent was used, or no release agent was used in place of using the sulfur-containing acid phosphoric ester, and the result was shown in Table 1. As compared with the sulfur-containing acid phosphoric esters of the present invention, when known internal release agents were used, the releasing was not easy, and the haze values of urethane flat plates were high. When any release agent was not used, releasing was not possible and therefore, the haze value could not be measured. EXAMPLE 39 100 Parts by weight of branched polyoxyalkylene ether polyol (OHV 28) was mixed with 0.1 part by weight of triethylene diamine and 0.1 part by weight of dibutyltin dilaurate as a polymerization catalyst, and 5 parts by weight of diethyl thiophosphate as an internal release agent was added thereto to form a uniform solution. To the resulting solution was added a urethane modified diphenyl methane diisocyanate (the isocyanate content being 23 %) in an amount which made the isocyanate index 107 and molded into a flat plate of 70 mm in diameter and 9 mm in thickness in an aluminum mold by a reaction injection molding method. Releasing was easy and the haze value of the resulting flat plate was as good as 0.4 %. COMPARATIVE EXAMPLE 77 The procedure of Example 39 was repeated except that 2 parts by weight of zinc stearate and 3 parts by weight of N,N,N'-tris(2-hydroxypropyl) ethylenediamine as internal release agents were heated to 90 - 100°C to make a uniform solution and used. The releasing was easy, but the haze value of the resulting flat plate was as poor as 23.7 %. EXAMPLES 40 - 51 Epoxy compounds and various additives were combined as shown in Table 2, and the sulfur-containing acid phosphoric esters were mixed therewith as internal release agents, and then each of the resulting mixtures were poured into a mold constituted of a resin gasket and glass mold members, followed by heat polymerization or photo-polymerization to form a flat plate resin of 70 mm in diameter and 9 mm in thickness. Evaluation of releasability was made by inserting a Teflon wedge between the molded product and the mold, and when released easily it was designated as "○", when released though there was some resistance, it was designated as "▵", and when not released, it was designated as "X" . The turbidity was determined by measuring the haze value of a flat plate urethane resin of 9 mm thick by using Degital Haze Computer HGM-2DP manufactured by Suga Shikenki K.K. according to JIS K 7105, 6.4 to one place of decimals. The results are shown in Table 2. COMPARATIVE EXAMPLES 78 - 101 In the combinations of monomers in the above-mentioned Examples, known internal release agents were used or no release agent was used in place of the sulfur-containing acid phosphoric esters and the procedures of the Examples were repeated, and there were measured the releasability and haze values of the resulting molded products. The results are shown in Table 2. As compared with the sulfur-containing acid phosphoric esters of the present invention, when known internal release agents were used, the releasing was not easy and the haze value of the resin was high, and when no release agent was used, releasing was not possible and therefore, the haze value could not be measured. EXAMPLES 52 - 63, COMPARATIVE EXAMPLES 102 - 125 Flat plate molded products of 70 mm in diameter and 9 mm in thickness were prepared by casting polymerization of olefin monomer compositions containing sulfur-containing acid phosphoric esters as internal release agents, containing known internal release agent, or containing no release agents as shown in Table 3 in molds composed of a resin gasket and glass discs. Evaluation for releasability was made by inserting a Teflon wedge between the molded product and the glass flat plate, and when released easily, it was designated as "○", and when released with resistance, it was designated as "X" . The turbidity of the molded product was determined by measuring the haze value at a portion of 9 mm thick with a digital haze computer HGM-2DP manufactured by Suga Shikenki K.K. to one place of decimals according to JIS-K- 7105, 6.4 . The results are shown in Table 3. EXAMPLES 64 - 74, COMPARATIVE EXAMPLES 126 - 147 Flat plate molded products of 70 mm in diameter and 9 mm in thickness were prepared by injection molding of acrylic resins composed of monomer compositions containing sulfur-containing acid phosphoric esters as internal release agents, or containing no release agents as shown in table 4. Evaluation for releasability was made by inserting a wedge between the molded product and a metal mold and when released easily, it was designated as "○", and when released with resistance, it was designated as "X". The turbidity of the molded product was determined by measuring the haze value at a portion of 9 mm thick with a digital haze computer HGM-2DP manufactured by Suga Shikenki K.K. to one place of decimals according to JIS-K-7105, 6.4. The results are shown in Table 4. EXAMPLES 75 - 84, COMPARATIVE EXAMPLES 148 - 167 Flat plate molded products composed of a polyene-polythiol resin of 70 mm in diameter and 9 mm in thickness were prepared by casting polymerization of monomer compositions containing sulfur-containing acid phosphoric esters as internal release agents, or containing no release agent as shown in Table 5 in molds composed of a resin gasket and glass discs. Evaluation for releasability was made by inserting a Teflon wedge between the molded product and the glass flat plate, and when released easily, it was designated as "○", and when released with resistance, it was designated as "X". The turbidity of the molded product was determined by measuring the haze value at a portion of 9 mm thick with a digital haze computer HGM-2DP manufactured by Suga Shikenki K.K. to one place of decimals according to JIS-K-7105, 6.4. The results are shown in Table 5. EXAMPLES 85 - 94, COMPARATIVE EXAMPLES 168 - 173 Flat plates of 70 mm in diameter and 9 mm in thick were prepared by injecting into metal molds at 130°C a composition of 2.2-bis(4-hydroxyphenyl) propane type polycarbonate powder having an average molecular weight of 15,000 and an internal release agent, or said powder without adding any internal release agent as shown in Table 6, after melted at a resin temperature of 250°C - 270°C. Evaluation for releasability was made by inserting a wedge between the molded product and the metal mold, and when released easily, it was designated as "○", and when released with resistance, it was designated as "X". The optical strain of the molded product was measured by Toshiba tester SVP-100. When there was no strain, the molded product was designated as "○". When there was strain, it was designated as "X". The turbidity of the molded product was determined by measuring the haze value of a flat plate resin of 9 mm thick with a digital haze computer HGM-2DP manufactured by Suga Shikenki K.K. to one place of decimals according to JIS-K-7105, 6.4. The results are shown in Table 6. Internal release agent Releasability Optical strain Haze value (%) Example 85 Dimethyl thiophosphate 0.001 wt% ○ ○ 0.0 Example 86 Diethyl thiophosphate 0.005 wt% ○ ○ 0.0 Example 87 Dioctyl thiophosphate 0.1 wt% ○ ○ 0.0 Example 88 Dioctadecyl thiophosphate 1.0 wt% ○ ○ 0.0 Example 89 Dimethyl Dithiophosphate 0.05 wt% ○ ○ 0.0 Example 90 Diisopropyl dithophosphate 0.5 wt% ○ ○ 0.0 Example 91 Dioctyl dithiophosphate 0.2 wt% ○ ○ 0.0 Example 92 Dioctadecyl dithiophosphate 0.8wt% ○ ○ 0.0 Example 93 Dimethyl thiophosphate 0.01 wt% ○ ○ 0.0 Dioctadecyl thiophosphate 0.1 wt% Example 94 Dibutyl thiophosphate 0.01 wt% ○ ○ 0.0 Dibutyl dithiophosphate 0.01 wt% Comparative Example 168 Stearyl glyceryl ether 0.2wt% ○ ○ 0.4 Comparative Example 169 Behenyl behenate 0.04 wt% X X 0.3 Comparative Example 170 Stearic acid monoglyceride 0.1 wt% ○ ○ 0.4 Comparative Example 171 Dimethyl polysiloxane 0.04 wt% X X 0.8 Comparative Example 172 Dioctyl phosphate 0.1 wt% X X 0.7 Comparative Example 173 None X X 0.0

Claims: Use of at least one sulphur-containing acid phosphoric ester selected from the group consisting of thiophosphoric acid esters and dithiophosphoric acid esters of the following formula as internal release agent in a resin selected from the group consisting of urethane resins, epoxy resins, polyolefin resins, polyene-polythiol resins, unsaturated polyester resins, phenolic resins, furan resins, xylene resins, formaldehyde resins, ketone resins, urea resins, melamine resins, aniline resins, sulfonamide resins, alkyd resins, polycarbonate resins, thermoplastic polyester resins, polyether resins, polyamide resins, polyimide resins, polyvinylketone resins, polyvinylether resins, and composite resins thereof; where X and Y are independently selected from the group consisting of an oxygen atom and a sulfur atom, at least one of X and Y is a sulfur atom, and R 1 and R 2 are independently alkyl groups. A method for molding a resin which comprises using at least one sulphur-containing acid phosphoric ester as an internal release agent as set forth in claim 1. The method according to claim 2 in which the resin is a transparent resin. The method according to claim 2 in which the resin is a urethane resin producible by polymerizing at least one iso(thio)cyanate compound selected from the group consisting of polyisocyanate compounds, polyisothiocyanate compounds, and isothiocyanate compounds containing a isocyanato group, with at least one active hydrogen compound selected from the group consisting of polyol compounds, polythiol compounds, and hydroxythiol compounds. The method according to claim 2 in which the resin is an epoxy resin producible by polymerizing at least one member selected from the group consisting of amine type epoxy compound, phenol type epoxy compound, alcohol type epoxy compound, epoxy compound derived from unsaturated compound, glycidyl ester type epoxy compound, urethane type epoxy compound, alicyclic epoxy compound, and epoxy compound having an epoxy group and an unsaturated double bond in the same molecule. The method according to claim 5 in which the epoxy resin is produced by using an epoxy resin curing agent selected from the group consisting of alcohols, phenols, thiols, carboxylic acids, carboxylic acid anhydrides, amines, amides, sulfonic acids, and isocyanates. The method according to claim 2 in which the resin is a polyolefin resin producible by polymerizing at least one monomer having an unsaturated double bond selected from the group consisting of aliphatic olefin compound, aromatic vinyl compound, acrylic acid ester compound, unsaturated nitrile compound, acrylic amide compound, allyl ester compound, allyl ether compound, allyl carbonate compound, and maleimide compound. The method according to claim 2 in which the resin is a polyene-polythiol resin producible by polymerizing a polyene compound selected from the group consisting of aliphatic olefin compound, aromatic vinyl compound, acrylic acid ester compound, ally ether compound, and ally carbonate compound, with a polythiol compound selected from the group consisting of aliphatic polythiol, aromatic polythiol, and heterocyclic polythiol. The method according to claim 2 in which R 1 and R 2 are independently selected from C 1 - C 18 alkyl groups. The method according to claim 2 in which the sulfur-containing acid phosphoric ester is added in an amount of 0.01 - 5 % by weight based on the total amount of monomers or the resin. A resin molded article produced by the method set forth in claim 2. The resin molded article according to claim 11 in which the molded article is transparent. The resin molded article according to any one of claim 11 and claim 12 in which the molded article is an optical product. The resin molded article according to claim 13 where the molded article is a plastic lens.

Inventors: KUSUMOTO MASAHIKO, NAGATA TERUYUKI, YAMASHITA HIROYUKI, KUSUMOTO, MASAHIKO, NAGATA, TERUYUKI, YAMASHITA, HIROYUKI
Applicants: MITSUI TOATSU CHEMICALS, MITSUI TOATSU CHEMICALS, INC.
Application year: 1993
Main classification: B29C33
IPC codes: C08K5, B29C33