SPECIFICATION POLYMERIZABLE COMPOSITION FOR POLYTHIOURETHANE OPTICAL MATERIAL TECHNICAL FIELD [0001] The present invention relates to a catalyst for the polythiourethanization reaction. More specifically, the invention relates to a catalyst having higher safety and exhibiting higher catalytic activity than those of an organic tin catalyst that has been widely used as a catalyst for the polythiourethanization reaction from the past, and a polythiourethane optical material produced by using the catalyst. BACKGROUND ART [0002] In' recent years, harmony with the global environment and decrease of the environmental load become objects in the manufacturing industry. Development of products or technologies in consideration of the environment has been speeded up. Due to a change in the external environment, even in the chemical industry, the use of compounds or heavy metal compounds with high toxicity has been independently suppressed, while there has been a movement to develop alternative technologies. There has also been such a movement in the polyurethane industry belonging to the technical field of the present invention, and, in particular, the regulation on the use of organic tin catalyst that have been widely used as catalysts for the production of polyurethane has been strengthened in developed countries taking the lead in this movement. Therefore, development of alternative catalysts has also been actively made. [0003] When polyurethane or polythiourethane is produced by the reaction of an isocyanate compound with an active hydrogen compound having a hydroxyl group or a mercapto group, a tertiary amine type catalyst or an organic metal type catalyst has been mainly used as a reaction catalyst. As the tertiary amine type catalyst, there have been used compounds such as triethylenediamine, N,N-dimethylethanolamine, triethylamine, N-ethylmorpholine and the like. As the organic metal type catalyst, there have been used organotin catalysts such as dibutyltin dichloride (DBC), dibutyltin dilaurate (DBTDL), dibutyltin diacetate and the like; organic acid salts and acetylacetonate complex compounds such as iron, nickel, zinc and the like. When both types of catalysts are compared, organic metal type catalysts generally have high activity, and the frequency of their use is high (Non-patent Document 1) from the viewpoint of reactivity. Furthermore, polyurethane or polythiourethane resins that have been produced by using these known catalysts have been used in various fields. Of such resins, a transparent resin made of polythiourethane belonging to the technical field of the present invention has been widely used as a plastic lens material (Patent Document 1) . Since a plastic lens is lightweight and hardly broken as compared to an inorganic lens that has been used from the past, and can be tinted, in late years, it has quickly come into wide use as an optical material of spectacle lenses, camera lenses and the like. [0004] As a catalyst to be used at the time of the production reaction of these polythiourethane resins which serve as useful optical materials, there have been widely used organotin catalysts including typical examples of DBC or DBTDL from the past from the viewpoint of high catalytic activity. However, as mentioned in the beginning, there has, in late years, been pointed out a problem in these organotin catalysts from the viewpoint of toxicity. [0005] For example, tributyltin contained in DBTDL as impurities and tributyltin chloride contained m DBC as impurities have a problem of the risk of injury to the human body as endocrine disrupters. Furthermore, there has already been a movement of controlling use of an organic tin compound in Europe taking the lead in this movement. Therefore, in the business world of spectacle lenses using polythiourethane resins, it has been urgently desired to develop a tin substituted catalyst. From now on, not only in Europe but also throughout the world, it is highly possible that the regulation on the use of organic tin compound is still more strengthened, while, in the polyurethane industry, it becomes essential to develop a catalyst with high safety and high activity which can be a substitute of an organic tin compound. [0006] For example, as altanatives of organic tin catalyst in the polyurethane field, there have been known a catalyst composed of a carboxylic acid metal compound and a quaternary ammonium salt compound (Patent Document 2), a catalyst composed of a two-ring tertiary amine compound and a quaternary ammonium salt compound (Patent Document 3), a metal catalyst of titanium and aluminum having an alkoxy group or a carboxy group in a ligand (Patent Document 4) and the like. These catalysts are mainly used as catalysts for the production of polyurethane resins produced from polyisocyanates and polyols. There is no case in which these catalysts are used as catalysts of polythiourethane optical materials produced from polyisocyanates and polythiols. In the field of the present invention, that is, the field of sulfur-containing plastic lenses, there has been reported a case in which dithiocarbamic acid salts of metals have been used for catalysts (Patent Document 5). However, there has not been reported a tin free catalyst which can be used for the production of polythiourethane resins that have come into wide use as materials for plastic lenses. [0007] To produce a polythiourethane resin as a material for a plastic lens, a casting polymerization method in which a polymerizable composition is generally injected into a mold for heat curing can be taken, whereas the polymerization reaction is carried out while gradually raising the temperature from low temperature to high temperature over several hours to several tens of hours. At that time, in order to obtain an optically homogeneous plastic lens, adding a catalyst is required to slowly carry out the polythiourethanization reaction controlled by heat lest thermal inhomogeneity be occurred while raising the temperature. Furthermore, in order to achieve full resin properties including optical properties, heat resistance and strength, it is necessary to complete the polymerization. In order to complete the polymerization, a method in which a catalyst with strong polymerization activity is used or an amount of the catalyst is increased can be cited. However, such a method has a problem such that the polymerization reaction has all been progressed while the prepared polymerizable composition is injected into a mold, that is, a sufficient pot life cannot be secured. Further, there is also a problem such that during the polymerization, exothermic heat is locally generated so that optical inhomogeneity is easily exhibited to lenses. As a method to solve this problem, for example, there has been reported a case in which the low-temperature activity is suppressed by using Lewis acid for a tertiary amine with strong activity together (Patent Document 6). Patent Document 1: Japanese Patent Publication No. 1992-58489 Patent Document 2: Japanese Patent Laid-open No. 2005-105084 Patent Document 3: Japanese Patent Laid-open No. 2005-105085 Patent Document 4: Japanese Patent Laid-open No. 2004-277621 Patent Document 5: Japanese Patent Laid-open No. 2004-269673 Patent Document 6: Japanese Patent No. 3220614 Non-patent Document 1: [Applied Technique for Latest Polyurethane] published by CMC Publishing Co., Ltd. in 1983, p. 27 to 31 DISCLOSURE OF THE INVENTION [0008] The present invention is to provide a tin free catalyst having excellent catalytic activity in place of an organotin catalyst that has been used as a catalyst for the production of polythiourethane optical materials from the past. [0009] That is, the present invention is specified by matters described in below: [1] a polymerizable composition for polythiourethane optical materials containing a compound represented by the general formula (1), one or two or more isocyanates selected from the group consisting of isocyanate compounds and isothiocyanate compounds, and one or two or more active hydrogen compounds each having a mercapto group, M(L)n (1) wherein, in the formula, M represents Al, Fe, Cu, Zn, Zr or Bi; L represents a dithiocarbamic acid group, a sulfonic acid group, a mono- or di-alkyl phosphoric acid ester group, a substituted acetylacetonato group or a halogen; and n represents an integer of 1 to 5; [2] the polymerizable composition for polythiourethane optical materials as set forth in [1], further containing a compound represented by the general formula (2), (Formula Removed) wherein, in the formula, R1, R2, R3 and R4 each independently represent hydrogen, monovalent or higher valent linear aliphatic, cyclic aliphatic or aromatic organic residues; R1, R2, R3 and R4 may be bonded with each other to form a ring; X represents an organic acid group or an inorganic acid group; and Y represents nitrogen or a phosphorus atom; [3] the polymerizable composition for polythiourethane optical materials as set forth in [2] , wherein, in the general formula (2) , R\ R^, R"^ and R* are each independently any one selected from the group consisting of an alkyl group having 1 to 18 carbon atoms, a hydroxyalkyl group having 1 to 18 carbon atoms, a phenyl group, a phenylalkyl group having 7 to 18 carbon atoms or an aminoalkyl group having 1 to 18 carbon atoms; [4] the polymerizable composition for polythiourethane optical materials as set forth in [2] or [3], wherein the compound of the general formula (2) is one or two or more kinds selected from the group consisting of a tetramethylammonium salt, a tetraethylammonium salt, a tetrapropylammonium salt, a tetrabutylammonium salt, a trioctylmethylammonium salt, a tributylbenzylammonium salt and a tetrabutylphosphonium salt; [5] the polymerizable composition for polythiourethane optical materials as set forth in [4], wherein the compound of the general formula (2) is one or two or more kinds selected from the group consisting of tetrabutylammonium chloride, tetrabutylammonium bromide, tetraethylammonium bromide, tetrabutylammonium tetrafluoroborate, trioctylmethylammonium chloride, tributylbenzylammonium chloride and tetrabutylphosphonium bromide; [6] the polymerizable composition for polythiourethane optical materials as set forth in any one of [1] to [5], wherein M in the general formula (1) is Zn or Fe; [7] the polymerizable composition for polythiourethane optical materials as set forth in any one of [1] to [6], wherein L in the general formula (1) is a group represented by the general formula (3) , (Formula Removed) wherein, in the formula, R5 and R6 each represent an alkyl group having 1 to 10 carbon atoms, a phenylalkyl group having 7 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms, and may be the same or different; and R5 and R6 may be bonded with each other to form a ring; [8] the polymerizable composition for polythiourethane optical materials as set forth in any one of [1] to [7] , wherein the compound represented by the general formula (1) is one or two or more kinds selected from the group consisting of zinc dimethyldithiocarbamate acid, zinc diethyldithiocarbamate and zinc di-n-butyldithiocarbamate; [9] the polymerizable composition for polythiourethane optical materials as set forth in any one of [2] to [8], wherein the molar ratio of the compound of the general formula (2) to the compound of the general formula (1) is not less than 0.01 but not more than 100; [10] the polymerizable composition for polythiourethane optical materials as set forth in any one of [1] to [9], wherein the isocyanates is an isocyanate compound; [11] the polymerizable composition for polythiourethane optical materials as set forth in [10], wherein the isocyanate compound is one or two or more kinds selected from the group consisting of m-xylylene diisocyanate, 2,5-bis(isocyanatomethyl)-bicyclo[2.2.1]heptane, 2,6-bis(isocyanatomethyl)-bicyclo[2.2.1]heptane, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane and hexamethylene diisocyanate, and the active hydrogen compound is one or two or more kinds selected from the group consisting of 4-mercaptomethyl-l,8-dimercapto-3,6-dithiaoctane, 5,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane, pentaerythritol tetrakis(3-mercaptopropionate), 1,1,3, 3-tetrakis(mercaptomethylthio)propane, 1, 1,2,2-tetrakis(mercaptomethylthio)ethane, 4,6-bis(mercaptomethylthio)-1, 3-dithiane and 2-(2,2-bis(mercaptomethylthio)ethyl)-1,3-dithietane; [12] a polythiourethane optical material obtained by curing the polymerizable composition for polythiourethane optical materials as set forth in any one of [1] to [11]; [13] a plastic lens composed of the polythiourethane optical material as set forth in [12]; [14] a process for producing the polythiourethane optical material, wherein the polymerizable composition for polythiourethane optical materials as set forth in any one of [1] to [11] is subjected to casting polymerization; and [15] a process for producing the polythiourethane optical material as set forth in any one of [2] to [11], wherein the total amount of the compound of the general formula (1) and the compound of the general formula (2) is not less than 0.0005 weight parts but not more than 5 weight parts based on the total 100 weight parts of the isocyanates and the active hydrogen compounds, and the compound of the general formula (1) is mixed with the compound of the general formula (2). [0010] In Patent Document 5, there has been disclosed a part of the compound represented by the general formula (1) of the present invention as a catalyst in the production of sulfur-containing plastic lenses. However, Patent Document 5 relates to the use of an episulfide type lens composed of an inorganic sulfur compound and an episulfide compound, whereas the present invention relates to the use of it as a catalyst for the production of polythiourethane optical material obtained from isocyanates and active hydrogen compounds each having a mercapto group. Furthermore, the present invention achieves catalytic activity equal to or superior to that of an organotin catalyst by using the compound represented by the general formula (1) . Furthermore, the effect of improvement of weather resistance of the obtained polythiourethane resin has been found. Due to the improvement of weather resistance, it is possible to control the deterioration of color hue in the lens that has been a problem when the lens is used for a long time as a plastic lens. [0011] Accordingly, the catalyst of the present invention is a tin free catalyst having excellent catalytic activity replacing the organotin catalyst that has been used as a catalyst for the production of polythiourethane optical materials from the past. In recent years, it is possible to use the tin free catalyst as a novel catalyst replacing the organotin catalyst. The control of use of the organotin catalyst has been strengthened. The polythiourethane resin obtained by the catalyst of the present invention satisfactorily meet the property requirements for optical materials, in particular, excelling in weather resistance as compared to that obtained by the organotin catalyst. Furthermore, by using the compound represented by the general formula (2) together, the catalytic activity of the compound represented by the general formula (1) is rapidly improved. Thus, the catalytic activity per unit mole of the compound is more excellent than that of the organotin catalyst. Accordingly, the amount of the catalyst added is small so that the amount of the compound other than the polythiourethane compound exhibiting physical properties by nature can be made small. [0012] The polythiourethane optical materials of the present invention obtained by using the aforementioned polymerizable composition for polythiourethane optical materials are used for optical materials of plastic lenses, prisms, optical fibers, information recording substrates, filters, light emitting diodes or the like, and particularly suitably used as plastic lens materials for spectacles. BRIEF DESCRIPTION OF THE DRAWINGS [0013] The aforementioned objects and other objects, characteristics and advantages become further clear by the appropriate embodiments to be described below and the following drawings accompanied thereto. Fig. 1 is a graph illustrating the time course of the viscosity of the polymerizable composition in Examples and Comparative Examples. BEST MODE FOR CARRYING OUT THE INVENTION [0014] The present invention will be illustrated in detail below. The present invention relates to a polymerizable composition for polythiourethane optical materials containing a compound represented by the general formula (1), one or two or more isocyanates selected from the group consisting of isocyanate compounds and isothiocyanate compounds, and one or two or more active hydrogen compounds each having a mercapto group, M(L)n (1) wherein, in the formula, M represents Al, Fe, Cu, Zn, Zr or Bi; L represents a dithiocarbamic acid group, a sulfonic acid group, a mono- or di-alkyl phosphoric acid ester group, a substituted acetylacetonato group or a halogen; and n represents an integer of 1 to 5. The present inventors have found that the compound represented by the general formula (1) has excellent catalytic activity equal to or superior to that of the organotin catalyst that has been used as a catalyst for the production of polythiourethane optical materials produced from isocyanates and the active hydrogen compounds each having a mercapto group. [0015] Furthermore, the present invention relates to a polymerizable composition for polythiourethane optical materials further containing a compound represented by the general formula (2), (Formula Removed) wherein, in the formula, R1, R2, R3 and R4 each independently represent hydrogen, monovalent or higher valent linear aliphatic, cyclic aliphatic or aromatic organic residues; R1, R2, R3 and R4 may be bonded with each other to form a ring; X represents an organic acid group or an inorganic acid group; and Y represents nitrogen or a phosphorus atom. The present inventors have found that the catalytic activity of the general formula (1) is rapidly improved by using the compound represented by the general formula (1) and the compound represented by the general formula (2) together, and the polythiourethane resin obtained by curing the polymerizable composition with much less amount of the catalyst added satisfactorily meet the property requirements for optical materials. [0016] M in the compound represented by the general formula (1) represents a metal, and represents Al, Fe, Cu, Zn, Zr or Bi. M is preferably Al, Fe, Zr or Zn and further preferably Zn or Fe. [0017] In the compound represented by the general formula (1), L represents a dithiocarbamic acid group, a sul iconic acid group, a mono- or di-alkyl phosphoric acid ester group, a substituted acetylacetonato group or a halogen. L is preferably a dithiocarbamic acid group, a substituted acetylacetonato group or a halogen and further preferably a dithiocarbamic acid group. [0018] As the dithiocarbamic acid group, L of a group represented by the general formula (3) is a more preferred embodiment, (Formula Removed) wherein, in the group represented by the general formula (3), R5 and R5 each represent an alkyl group having 1 to 10 carbon atoms, a phenyl alKyl group having 7 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms, and may be the same or different; and R5 and R6 may be bonded with each other to form a ring. [0019] Herein, concrete examples of the alkyl group having 1 to 10 carbon atoms include alkyl groups such as a metliyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group and the like. Concrete examples of the phenylalkyl group having 7 to 10 carbon atoms include a benzyl group, a phenylethyl group, a phenylpropyl group and a phenylbutyl group. Concrete examples of the aryl group having 6 to 10 carbon atoms include aryl groups such as a phenyl group, a tolyl group, a xylyl group, a mesityl group, a naphthyl group and the like. However, R^ and R^ are not restricted to these exemplified compounds . Furthermore, R" amd R^ may be bonded with each other to form a pyrrolidine ring or a piperidine ring. [0020] Examples of the group represented by the general formula (3) include dithiocarbamic acid groups of the following dithiocarbamic acids, but are not restricted to these exemplified compounds. Concrete examples thereof include dithiocarbamic acids such as N,N-dimethyldithiocarbamic acid, N,N-diethyldithiocarbamic acid, N,N-dipropyldithiocarbamic acid, N,N-dibutyldithiocarbamic acid, N-ethyl-N-phenyldithiocarbamic acid, N,N-dibenzyldithiocarbamic acid and the like, and derivatives thereof. [0021] Examples of the sulfonic acid group include sulfonic acid groups of the following sulfonic acids, but are not restricted to these exemplified compounds. Concrete examples thereof include sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, butanesulfonic acid, pentanesulfonic acid, hexanesulfonic acid, heptanesulfonic acid, octanesulfonic acid, nonanesulfonic acid, decanesulfonic acid, undecanesulfonic acid. dodecanesulfonic acid, tetradecanesulfonic acid, hexadecanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, dodecylbenzenesulfonic acid, trifluoromethanesulfonic acid, fluorosulfonic acid and the like, and derivatives thereof. [0022] Examples of an ester alkyl group of the mono- or di-alkyl phosphoric acid ester group include the following alkyl groups, but are not restricted to thereto. Concrete examples thereof include alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a dipentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, a dodecyl group, a tetradecyl group, a dihexadecyl group and the like; oxyethylene groups such as a methoxyethyl group, an ethoxyethyl group, a propoxyethyl group, a butoxyethyl group and the like; and polyoxyethylene groups. Ester alkyl groups of dialkyl phosphoric acid ester may be the same or different. [0023] Examples of the substituted acetylacetonato group include 2,2, 6, 6-tetramethyl-3,5-heptanedionato groups, but are not restricted thereto. [0024] Examples of halogen include fluorine, chlorine, bromine and iodine. [0025] When one or two or more isocyanates selected from the group consisting of isocyanate compounds and isothiocyanate compounds are reacted with one or two or more active hydrogen compounds each having a mercapto group to produce polythiourethane optical materials, preferred examples of the aforementioned compound represented by the general formula (1) include iron dialkyldithiocarbamate, copper dialkyldithiocarbamate, zinc dialkyldithiocarbamate, zinc alkyl phenyl dithiocarbamate, zinc diaryldithiocarbamate, iron acetylacetonato, copper acetylacetonato and zinc acetylacetonato, and farther preferably zinc N,N-dimethyldithiocarbamate, zinc N,N-diethyldithiocarbamate, zinc N,N-di-n-butyidithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate and zinc N,N-dibenzyldithiocarbamate. These compounds of the general formula (1) can be used singly, or two or more compounds can be used in combination. [0026] Furthermore, in view of the solubility into a monomer of isocyanates, active hydrogen compounds and the like or resin properties that are required as a plastic spectacle lens of the generated resin, among the foregoing compounds, particularly preferred are zinc N,N-dimethyldithiocarbamate, zinc N,N-diethyldithiocarbamate and zinc N,N-di-n-butyldithiocarbamate. When these compounds are used as catalysts, weather resistance of resin properties of the polythiourethane optical material is particularly improved. Due to the improvement of weather resistance, it is possible to provide a plastic lens in which the deterioration of color hue is suppressed when the lens is used for a long time. [0027J The compound represented by the general formula (1) can be contained in the polymerizable composition for polythiourethane optical materials without using tertiary amine having strong activity with much less amount of the compound added than that of the conventional organotin catalyst. The polythiourethane resin obtained by curing the polymerizable composition satisfactorily meets the property requirements for optical materials. Furthermore, a sufficient pot life can be secured until the composition is injected into a mold, and weather resistance of the obtained resin is particularly excellent. Therefore, the catalyst can be available as a novel catalyst replacing the organotin catalyst. [0028] Examples of R1, R2, R3 and R4 in the compound represented by the general formula (2) include hydrogen or monovalent or higher valent organic residues derived from linear aliphatic compounds such as methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tetradecane, hexadecane, octadecane, ethylene, propylene, 1-butene, 2~butene, butadiene and the like; monovalent or higher valent organic residues derived from cyclic aliphatic compounds such as cyclopentane, cyclopentene, cyclopentadiene, cyclohexane, 1,2-dimethylcyclohexane, 1,3-dimethylcyclohexane, 1,4-dimethylcyclohexane, cyclohexene, 1,3-cyclohexadiene, 1,4-cyclohexadiene, norbornane, 2,3-dimethylnorbornane, 2,5-dimethylnorbornane, 2,6-dimethylnorbornane, bis(4-methylcyclohexyl)methane and the 11 ke ; monovalent or higher valent organic residues derived from aromatic compounds such as benzene, toluene, o-xylene, m-xylene, p-xylene, naphthalene, biphenyl, anthracene, perylene, styrene, ethylbenzene and the like; monovalent or higher valent organic residues derived from alcohol compounds such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol and the like; monovalent or higher valent organic residues derived from primary amine compounds such as ethylamme, n-propylamme, isopropylamme, n-butylamme, sec-butylamme, ter-butylamme, pentylamme, hexylamme, heptylamme, octylamme, decylamme, laurylamme, myristylamme, 3-pentylamine, 2-ethylhexylamine, 1,2-dimethylhexylamine and the like; monovalent or higher valent organic residues derived from secondary amine compounds such as diethylamme, dipropylamme, di-n-butylamme, di-sec-butylamme, diisobutyj amine, di-n-pentylamme, di-3-pentylamine, dihexylama ne, dioctylamme, di(2-ethylhexyl)amine, methylhexylamme and the like; and monovalent or higher valent organic residue^s derived from tertiary amine compounds such as triethylamme, tri n-butylamme, tri n-hexylamme, N, N-diisopropylethylamme, triethylene diamine, triphenylamme, N, N-dimethylethanolamme, N,N-diethylethanolamine, N,N-dibutylethanolam me, triethanolamme, N-ethyldiethanolarame, N,N-dimethylbenzylamme, N, N-diethylbenzylamme, tribenzylamme, N-methyldibenzylamme and the like, but are not restricted only to these exemplified compounds. Furthermore, R1, R2, R3 and R4 may be bonded with each other to form a ring. [0029] Furthermore, it is more preferable that the aforementioned R^, R2, R3 and R4 are each independently an alkyl group having 1 to 18 carbon atoms, a hydroxyalkyl group having 1 to L8 carbon atoms or an ammoalkyl group having 1 to 18 carbon atoms. [0030] Examples of X m the general formula (2) include organic acid groups derived from organic acids such as formic acid, acetic acid, propionic acid, butanoic acid, 2-ethylhexanoic acid, oxalic acid, tartaric acid, succinic acid, fumaric acid, maleic acid, lactic acid, benzoic acid, citric acid, benzenesulfonic acid, toluenesulfonic acid, methanesulfonic acid, phosphoric ester, tetraphenyl boron and the like, and derivatives thereof; and inorganic acid groups derived from inorganic acids such as hydrohalogen acid, perchloric acid, carbonic acid, hydrocarbonic acid, sulfuric acid, phosphoric acid, boric acid and the like, but are not restricted only to these exemplified compounds. [0031] When Y m the general formula (2) is a nitrogen atom, concrete examples of the compound of the general formula (2) include quaternary ammonium salt compounds each having an alkyl group such as tetramethylammonium chloride, tetraethylamrnonium chloride, tetrapropylammonium chloride, tetrabutylammonlum chloride, tetrahexylammonium chloride, tetraoctylammonium chloride. trimethyloctylammonium chloride, trimethylphenylammonium chloride, trimethylbenzylammonium chloride, triethyl-n-octylammoniura chloride, triethylbenzylammonium chloride, tri-n-butyl-n-octylammonium chloride,, tri-n-butylbenzylammonium chloride, methyl triphenylammonium chloride, ethyl triphenylammonium chloride, n-butyl triphenylammonium chloride, trimethylcetylammonium chloride, trimethylstearylammonium chloride, dimethylethylcetylammonium chloride, dimethyl didecylammonium chloride, dimethyl di-n-dodecylammonium chloride, dimethyl distearylammonium chloride, n-octyl dimethylbenzylammonium chloride, n-dodecyl dimethylbenzylammonium chloride, stearyl dimethylbenzylammonium chloride, triethyl-n-dodecylammonium chloride, tri-n-hexylmethylammonium chloride, tri-n-octylmethylammonium chloride, tri-n-decylmethylammonium chloride, tri-n-dodecylmethylammonium chloride, tri-n-octyl-n-dodecylammonium chloride, diethyl dicyclohexylammonium chloride, 1-methylpyridinium chloride, 1-ethylpyridinium chloride, 1-n-butylpyridinium chloride, 1-n-hexylpyridinium chloride, 1-n-octylpyridinium chloride, 1-n-dodecylpyridinium chloride, 1-phenylpyridinium chloride, 1-methyl-4-methylpyridinium chloride, l-ethyl-4-methylpyridinium chloride, 1-n-butyl-4-methylpyridinium chloride, l-n-hexyl-4-methylpyridinium chloride, l-n-octyl-4-methylpyridinium chloride, 1-n-dodecyl-4-methylpyridinium chloride, l-phenyl-4-methylpyridinium chloride, tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetrahexylammonium bromide, tetraoctylammonium bromide, trimethyloctylammonium bromide, trimethylphenylammonium bromide, trimethylbenzylammonium bromide, triethyl-n-octylammonium bromide, triethylbenzylammonium bromide, tri-n-butyl-n-octylammoniura bromide, tri-n-butylbenzylammonium bromide, methyl triphenylammonium bromide, ethyl triphenylammonium bromide, n-butyl triphenylammonium bromide, trimethylcetylaminonium bromide, trimethylstearylammonium bromide, dimethylethylcetylammonium bromide, dimethyl didecylammonium bromide, dimethyl di-n-dodecylammonium bromide, dimethyl distearylammonium bromide, n-octyl dimethyl benzylammonium bromide, n-dodecyl dimethyl benzylammonium bromide, stearyl dimethyl benzylammonium bromide, triethyl-n-dodecylammonium bromide, tri-n-hexylmethylammonium bromide, tri-n-octylmethylammonium bromide, tri-n-decylmethylammonium bromide, tri-n-dodecylmethylammonium bromide, tri-n-octyl-n-dodecylammonium bromide, diethyl dicyclohexylammonium bromide, 1-methylpyridinium bromide, 1-ethylpyridinium bromide, 1-n-butylpyridinium bromide, 1-n-hexylpyridinium bromide, 1-n-octylpyridinium bromide, 1-n-dodecylpyridinium bromide, 1-phenylpyridinium bromide, l-methyl-4-methylpyridinium bromide, l-ethyl-4-methylpyridinium bromide, l-n-butyl-4-methylpyridinium bromide, l-n-hexyl-4-methylpyridinium bromide. l-n-octyl-4-methylpyridinium bromide, l-n-dodecyl-4-methylpyridinium bromide, 1-phenyl-4-methylpyridinium bromide, tetramethylammonium fluoride, tetraethylammonium fluoride, tetrapropylammonium fluoride, tetrabutylammonium fluoride, tetrahexylammonium fluoride, tetraoctylammonium fluoride, trimethyloctylammonium fluoride, trimethylphenylammonium fluoride, trimethylbenzylammonium fluoride, triethyl-n-octylammonium fluoride, triethylbenzylammonium fluoride, tri-n-butyl-n-octylammonium fluoride, tri-n-butylbenzylammonium fluoride, methyl triphenylammonium fluoride, ethyl triphenylammonium fluoride, n-butyl triphenylammonium fluoride, trimethylcetylammonium fluoride, trimethylstearylammonium fluoride, dimethylethylcetylammonium fluoride, dimethyl didecylammonium fluoride, dimethyl di-n-dodecylammonium fluoride, dimethyl distearylammonium fluoride, n-octyl dimethyl benzylammonium fluoride, n-dodecyl dimethyl benzylammonium fluoride, stearyl dimethyl benzylammonium fluoride, triethyl-n-dodecylammonium fluoride, tri-n-hexylmethylammonium fluoride, tri-n-octylmethylammonium fluoride, tri-n-decylmethylammonium fluoride, tri-n-dodecylmethylammonium fluoride, tri-n-octyl-n-dodecylammonium fluoride, diethyl dicyclohexylammonium fluoride, 1-methylpyridinium fluoride, 1-ethylpyridinium fluoride, 1-n-butylpyridinium fluoride, 1-n-hexylpyridinium fluoride, 1-n-octylpyridinium fluoride, 1-n-dodecylpyridinium fluoride, 1-phenylpyridinium fluoride. l-methyl-4-methylpyridinium fluoride, l-ethyl-4-methylpyridinium fluoride, l-n-butyl-4-methylpyridinium fluoride, l-n~hexyl-4-inethylpyridinium fluoride, l-n-octyl-4-methylpyridinium fluoride, l-n-dodecyl-4-methylpyridinium fluoride, l-phenyl-4-methylpyridinium fluoride, tetramethylammonium iodide, tetraethylammonium iodide, tetrapropylanunonium iodide, tetrabutylammonium iodide, tetrahexylammonium iodide, tetraoctylammonium iodide, trimethyloctylaramonium iodide, trimethylphenylammonium iodide, trimethylbenzylaitimonium iodide, triethyl-n-octylammonium iodide, triethylbenzylammonium iodide, tri-n-butyl-n-octylammonium iodide, tri-n-butylbenzylammonium iodide, methyl triphenylammonium iodide, ethyl triphenylammonium iodide, n-butyl triphenylammonium iodide, trimethylcetylammonaum iodide, trimethylstearylammonium iodide, dimethylethy]cetylammonium iodide, dimethyl didecylammonium iodide, dimethyl di-n-dodecylammonium iodide, dimethyl distearvlammonium iodide, n-octyl dimethyl benzylaramonium iodide, n-dodecyl dimethyl benzylammonium iodide, stearyl dimethyl benzyLammonium iodide, triethyl-n-dodecylammonium iodide, tri-n-hexylmethylammonium iodide, tri-n-octylmethylammonium iodide, tri-n-decylmethylammonium iodide, 1 ri-n-dodec/lmethylammonium iodide, tri-n-octyl-n-dodecylammonium iodide, diethyl dicyclohexylammonium iodide, 1-methylpyridinium iodide, 1-ethylpyridinium iodide, 1-n-butylpyridinium iodide, l-n-hexylpyridmium iodide, l-n-octylpyridmiurn iodide, 1-n-dodecylpyridinium iodide, l-phenylpyridinium iodide, l-methyl-4-methylpyridinium iodide, l-ethyl-4-methylpyridinium iodide, l-n-butyl-4-methylpyridinium iodide, l-n-hexyl-4-methylpyridinium iodide, l-n-octyl-4-methylpyridinium iodide, l-n-dodecyl-4-methylpyridinium iodide, l-phenyl-4-methylpyridinium iodide, tetramethylammonium hydroxide, tetraethylairmonium hydroxide, tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, trimethyloctylammonium hydroxide, trimethylphenylammonium hydroxide, trimethylbenzylammonium hydroxide, triethyl-n-octylammonium hydroxide, triethylbenzylamnionium hydroxide, tri-n-butyl-n-octylammonium hydroxide, tri-n-butylbenzylammonium hydroxide, methyl triphenylammonium hydroxide, ethyl triphenylammonium hydroxide, n-butyl triphenylammonium hydroxide, trimethylcetylammonium hydroxide, trimethyistearylammonium hydroxide, dimethylethylcetylammonium hydroxide, dimethyl didecylammonium hydroxide, dimethyl di-n-dodecylammonium hydroxide, dimethyl distearylammonium hydroxide, n-octyl dimethyl benzylammonium hydroxide, n-dodecyl dimethyl benzylammonium hydroxide, stearyl dimethyl benzylammonium hydroxide, triethyl-n-dodecylaramonium hydroxide, tri-n-hexylmethylammonium hydroxide, tri-n-octylmethylammonium hydroxide, tri-n-decylmethylammonium hydroxide, tri-n-dodecylmethylammonium hydroxide, tri~n-octyl-n-dodecylammonium hydroxide, diethyl dicyclohexylammonium hydroxide, 1-methylpyridinium hydroxxde, 1-ethylpyridinium hydroxide, 1-n-butylpyridinium hydroxide, l-n-hexylpyridmium hydroxide, l-n-octylpyridinium hydroxide, 1-n-dodecylpyridinium hydroxide, 1-phenylpyridinium hydroxide, l-methyl-4-methylpyridinium hydroxide, l-ethyl-4-methylpyridinium hydroxide, l-n-butyl-4-methylpyridinium hydroxide, l-n-hexyl-4-methylpyridinium hydroxide, l-n-octyl-4-methylpyridinium hydroxide, l-n-dodecyl-4-methylpyridinium hydroxide, 1-phenyl-4-methylpyridinium hydroxide, tetramethylammonium tetrafluoroborate, tetraethylammonium tetrafluoroborate, tetrapropylammonium tetrafluoroborate, tetrabutylammonium tetrafluoroborate, tetrahexylammonium tetrafluoroborate, tetraoctylammonium tetrafluoroborate, trimethyloctylammonium tetrafluoroborate, trimethylphenylammonium tetrafluoroborate, trimethylbenzylammonium tetrafluoroborate, triethyl-n-octylammonium tetrafluoroborate, triethylbenzylammonium tetrafluoroborate, tri-n-butyl-n-octylammonium tetrafluoroborate, tri-n-butylbenzylammonium tetrafluoroborate, methyl triphenylammonium tetrafluoroborate, ethyl trLphenylammonium tetrafluoroborate, n-butyl triphenylammonium tetrafluoroborate, trimethylcetylammonium tetrafluoroborate, trimethylstearylammonium tetrafluoroborate. dimethylethylcetylammonium tetrafluoroborate, dimethyl didecylammonium tetrafluoroborate, dimethyl di-n-dodecylammonium tetrafluoroborate, dimethyl distearylammonium tetrafluoroborate, n-octyl dimethyl benzylammonium tetrafluoroborate, n-dodecyl dimethyl benzylammonium tetrafluoroborate, stearyl dimethyl benzylammonium tetrafluoroborate, triethyl-n-dodecylammonium tetrafluoroborate, tri-n-hexylmethylammonium tetrafluoroborate, tri-n-octylmethylammonium tetrafluoroborate, tri-n-decylmethylammonium tetrafluoroborate, tri-n-dodecylmethylammonium tetrafluoroborate, tri-n-octyl-n-dodecylammonium tetrafluoroborate, diethyl dicyclohexylammonium tetrafluoroborate, 1-methylpyridinium tetrafluoroborate, 1-ethylpyridinium tetrafluoroborate, 1-n-butylpyridinium tetrafluoroborate, 1-n-hexylpyridinium tetrafluoroborate, 1-n-octylpyridinium tetrafluoroborate, 1-n-dodecylpyridinium tetrafluoroborate, 1-phenylpyridinium tetrafluoroborate, 1-methyl-4-methylpyridinium tetrafluoroborate, l-ethyl-4-methylpyridinium tetrafluoroborate, l-n-butyl-4-methylpyridinium tetrafluoroborate, l-n-hexyl-4~methylpyridinium tetrafluoroborate, l-n-octyl-4-methylpyridinium tetrafluoroborate, l-n-dodecyl-4-methylpyridinium tetrafluoroborate, l-phenyl-4-methylpyridinium tetrafluoroborate, tetramethylammonium hexafluorophosphate, tetraethylammonium hexafluorophosphate, tetrapropylammonium hexafluorophosphate, tetrabutylammonium hexafluorophosphate, tetrahexylammonium hexafluorophosphate, tetraoctylammonium hexafluorophosphate. trimethyloctylammonium hexafluorophosphate, trimethylphenylammonium hexafluorophosphate, trimethylbenzylammonium hexafluorophosphate, triethyl-n-octylammonium hexafluorophosphate, triethylbenzylammonium hexafluorophosphate, tri-n-butyl-n-octylammonium hexafluorophosphate, tri-n-butylbenzylammonium hexafluorophosphate, methyl triphenylammonium hexafluorophosphate, ethyl triphenylammonium hexafluorophosphate, n-butyl triphenylammonium hexafluorophosphate, trimethylcetylammonium hexafluorophosphate, trimethylstearylammonium hexafluorophosphate, dimethylethylcetylammonium hexafluorophosphate, dimethyl didecylammonium hexafluorophosphate, dimethyl di-n-dodecylammonium hexafluorophosphate, dimethyl distearylammonium hexafluorophosphate, n-octyl dimethyl benzylammonium hexafluorophosphate, n-dodecyl dimethyl benzylammonium hexafluorophosphate, stearyl dimethyl benzylammonium hexafluorophosphate, triethyl-n-dodecylammonium hexafluorophosphate, tri-n-hexylmethylammonium hexafluorophosphate, tri-n-octylmethylammonium hexafluorophosphate, tri-n-decylmethylammonium hexafluorophosphate, tri-n-dodecylmethylammonrum hexafluorophosphate, tri-n-octyl-n-dodecylammonium hexafluorophosphate, diethyl dicyclohexylammonium hexafluorophosphate, 1-methylpyridinium hexafluorophosphate, 1-ethylpyridinium hexafluorophosphate, 1-n-butylpyridinium hexafluorophosphate, 1-n-hexylpyridinium hexafluorophosphate, 1-n-octylpyridinium hexafluorophosphate, 1-n-dodecylpyridinium hexafluorophosphate, l-phenylpyridinium hexafluorophosphate, l-methyl-4-methylpyridinium hexafluorophosphate, l-ethyl-4-methylpyridinium hexafluorophosphate, l-n-butyl-4-methylpyridinium hexafluorophosphate, l-n-hexyl-4-methylpyridinium hexafluorophosphate, l-n-octyl-4-methylpyridinium hexafluorophosphate, l-n-dodecyl-4-methylpyridinium hexafluorophosphate, l-phenyl-4-methylpyridinium hexafluorophosphate, p-toluenesulfonic acid tetramethylammonium, p-toluenesulfonic acid tetraethylammonium, p-toluenesulfonic acid tetrapropylammoniurn, p-toluenesulf onic acid tetrabutylammonium, p-toluenesulfonic acid tetrahexylammonium, p-toluenesulfonic acid tetraoctylammonium, p-toluenesulfonic acid trimethyloctylammonium, p-toluenesulfonic acid trimethylphenylammonium, p-toluenesulfonic acid trimethylbenzylammonium, p-toluenesulfonic acid triethyl-n-octylammonium, p-toluenesulfonic acid triethylbenzylammonium, p-toluenesulfonic acid tri-n-butyl-n-octylammonium, p-toluenesulfonic acid tri-n-butylbenzylammonium, p-toluenesulfonic acid methyl triphenylammonium, p-toluenesulfonic acid ethyl triphenylammonium, p-toluenesulfonic acid n-butyl triphenylammonium, p-toluenesulfonic acid trimethylcetylammonium, p-toluenesulfonic acid trimethylstearylammonium, p-toluenesulfonic acid dimethylethylcetylammonium, p-toluenesulfonic acid dimethyl didecylammonium, p-toluenesulf onic acid dimethyl di-n-dodecylamrnonium, dimethyl distearylammonium, p-toluenesulfonic acid n-octyl dimethyl benzylammonium, p-toluenesulfonic acid n-dodec/1 dimethyl benzylammonium, p-toluenesulfonic acid stearyl dimethyl benzylammonium, p-toluenesulfonic acid triethyl-n-dodecylammonium, p-toluenesulfonic acid tri-n-hexylmethylammonium, p-toluenesulfonic acid tri-n-octylmethylammonium, p-toluenesulfonic acid tri-n-decylmethylammonium, p-toluenesulfonic acid tri-n-dodecylmethylammonium, p-toluenesulfonic acid tri-n-octyl-n-dodecylammonium, p-toluenesulfonic acid diethyl dicyclohexylammonium, p-toluenesulfonic acid 1-methylpyridinium, p-toluenesulfonic acid 1-ethylpyridimum, p-toluenesulfonic acid 1-n-butylpyridinium, p-toluenesulfonic acid 1-n-hexylpyridinium, p-toluenesulfonic acid 1-n-octylpyridinium, p-toluenesulfonic acid 1-n-dodecylpyridinium, p-toluenesulfonic acid 1-phenylpyridinium, p-toluenesulfonic acid l-methyl-4-methylpyridinium, p-toluenesulfonic acid l-ethyl-4-methylpyridinium, p-toluenesulfonic acid l-n-butyl-4-methylpyridinium, p-toluenesulfonic acid l-n-hexyl-4-methylpyridinium, p-toluenesulfonic acid l-n-octyl-4-methylpyridinium, p-toluenesulfonic acid l-n-dodecyl-4-methylpyridinium, p-toluenesulfonic acid 1-phenyl-4-methylpyridinium, perchloric acid tetramethylammonium, perchloric acid tetraethylammonium, perchloric acid tetrapropylammonium, perchloric acid tetrabutylammonium, perchloric acid tetrahexylammonium, perchloric acid tetraoctylammonium, perchloric acid trimethyloctylammonium, perchloric acid trimethylphenylammonium, perchloric acid trimethylbenzylammonium, perchloric acid triethyl-n-octylammonium, perchloric acid triethylbenzylammonium, perchloric acid tri-n-butyl-n-octylaminonium, perchloric acid tri-n-butylbenzylammonium, perchloric acid methyl triphenylammonium, perchloric acid ethyl triphenylammonium, perchloric acid n-butyl triphenylammonium, perchloric acid trimethylcetylammonium, perchloric acid trimethylstearylammonium, perchloric acid dimethylethylcetylammonium, perchloric acid dimethyl didecylammonium, perchloric acid dimethyl di-n-dodecylammonium, dimethyl distearylammonium, perchloric acid n-octyl dimethyl benzylammonium, perchloric acid n-dodecyl dimethyl benzylammonium, perchloric acid stearyl dimethyl benzylammonium, perchloric acid triethyl-n-dodecylammonium, perchloric acid tri-n-hexylmethylammonium, perchloric acid tri-n-octylmethylammonium, perchloric acid tri-n-decylmethylammonium, perchloric acid tri-n-dodecylmethylammonium, perchloric acid tri-n-octyl-n-dodecylammonium, perchloric acid diethyl dicyclohexylammonium, perchloric acid 1-methyipyridinium, perchloric acid 1-ethylpyridinium, perchloric acid 1-n-butylpyridinium, perchloric acid 1-n-hexylpyridinium, perchloric acid 1-n-octylpyridinium, perchloric acid 1-n-dodecylpyridinium, perchloric acid 1-phenylpyridinium, perchloric acid l-methyl-4-methylpyridinium, perchloric acid l-ethyl-4-methylpyridinium, perchloric acid l-n-butyl-4-methylpyridinium, perchloric acid l-n-hexyl-4-methylpyridinium, perchloric acid l-n-octyl-4-methylpyridinium, perchloric acid l-n-dodecyl-4-methylpyridinium, perchloric acid l-phenyl-4-methylpyridinium and the like; quaternary ammonium salt compounds each having a hydroxyalkyl group such as (2-hydroxypropyl)trimethylammonium chloride, hydroxyethyl trimethylammonium chloride, trimethylammoethoxyethanol chloride, (2-hydroxypropyl)trimethylammonium bromide, hydroxyethyl trimethylammonium bromide, trimethyiammoethoxyethanol bromide, (2-hydroxypropyl)trimethylammonium fluoride, h/droxyethyl trimethylammonium fluoride, trimethylammoethoxyethanol fluoride, (2-hydroxypropyl)trimethylammonium iodide, hydroxyethyl trimethylammonium iodide, trimethylammoethoxyethanol iodide, (2-hydroxypropyl)trimethylammonium hydroxide, hydroxyethyl trimethylammonium hydroxide, trimethylammoethoxyethanol hydroxide, (2-hydroxypropyl)trimethylammonium tetrafluoroborate, hydroxyethyl trimethylammonium tetrafluoroborate, trimethylammoethoxyethanol tetrafluoroborate, (2-hydroxypropyl)trimethylammonium hexafluorophosphate, hydroxyethyl trimethylammonium phosphate, trimethylaminoethoxyethanol phosphate, p~toluenesulfonic acid (2-hydroxypropyl)trimethylammonium, p-toluenesulfonic acid hydroxyethyl trimethylammonium, p-toluenesulfonic acid trimethylammoethoxyethanol, perchloric acid(2-hydroxypropyl)trimethylammonium, perchloric acid hydroxyethyl trimethylammonium, perchloric acid trimethylammoethoxyethanol and the like; and quaternary ammonium compounds each having an ammoalkyl group such as l-methyl-l-azania-4-azabicyclo[2,2,2]octanium chloride, 1,l-dimethyl-4-methylpiperidinium chloride, 1-methylmorpholinium, 1-methylpiperidinium chloride, l-methyl-l-azania-4-azabicyclo[2,2,2]octanium bromide, 1,l-dimethyl-4-methylpiperidinium, 1-methylmoroholinium bromide, 1-methylpiperidinium bromide, l-methyl-l-azania-4-azabicyclo[2,2,2]octanium fluoride, 1,l-dimethyl-4-methylpiperidinium fluoride, 1-methylmorpholinium fluoride, 1-methylpiperidinium fluoride, l-methyl-l-azania-4-azabicyclo[2,2,2]octanium iodide, 1,l-dimethyl-4-methylpiperidinium iodide, 1-methylmorpholinium iodide, 1-methylpiperidinium iodide, l-methyl-l-azania-4-azabicyclo[2,2,2]octanium hydroxide, 1,l-dimethyl-4-methylpiperidinium hydroxide, 1 -methylmorpholinium hydroxide, l-methylpiperidmium hydroxide, l-methyl-l-azania-4-azabicyclo[2,2,2]octanium trimethylammonium tetrafluoroborate, 1,l-dimethyl-4-methylpiperidinium trimethylammonium tetrafluoroborate, l-methylmorpholmium trimethylammonium tetrafluoroborate, l-methylpiperidmium trimethylammonium tetrafluoroborate, l-methyl-l-azania-4-azabicyclo[2,2,2]octanium hexafluorophosphate, 1,l-dimethyl-4-methylpiperidinium hexafluorophosphate, 1-methylmorpholinium hexafluorophosphate. 1-methylpiperidinium hexafluorophosphate, p-toluenesulfonic acid l-methyl-l-azania-4-azabicyclo[2,2,2]octanium, p-toluenesulfonic acid 1,1-dimethyl-4~methylpiperidinium, p-toluenesulfonic acid 1-methylmorpholinium, p-toluenesulfonic acid 1-methylpiperidinium, perchloric acid l-methyl-l-azania-4-a2abicyclo [2 , 2, 2 ] octaniura, perchloric acid 1, l-dimethyl-4-rnethylpiperidinium, perchloric acid l-methylmorpholmium, perchloric acid l-methylpiperidmium and the like, but are not restricted only to these exemplified compounds. [0032] Furthermore, when Y m the general formula (2) is a phosphorus atom, concrete examples of the compound of the general formula (2) include quaternary phosphonium salt compounds each having an alkyl group such as tetramethylphosphonium chloride, tetraethylphosphonium chloride, tetrapropylphosphonium chloride, tetrabutylphosphonium chloride, tetrahexylphosphonium chloride, tetraoctylphosphonium chloride, ethyl triphenylphosphonium chloride, tetraphenylphosphonium chloride, butyl triphenylphosphonium chloride, benzyl triphenylphosphonium chloride, methoxymethyl triphenylphosphonium chloride, tetramethylphosphonium bromide, tetraethylphosphonium bromide, tetrapropylphosphonium bromide, tetrabutylphosphonium bromide, tetrahexylphosphonium bromide, tetraoctylphosphonium bromide, ethyl triphenylphosphonium bromide, tetraphenylphosphonium bromide, butyl triphenylphosphonium bromide, benzyl triphenylphosphonium bromide, methoxymethyl triphenylphosphonium bromide, ethyl triphenylphosphonium acetate, ethyl triphenylphosphonium iodide, tetraethylphosphonium hydroxide, tetrabutylphosphonium hydroxide, tetraphenylphosphonium tetrakis(4-methylphenyl)borate, tetraphenylphosphonium tetraphenylborate, tetrabutylphosphonium-o,o-diethyl phosphorodithioate and the like; and quaternary ammonium salt compounds each having a hydroxyalkyl group such as tetrahydroxymethylphosphonium sulfate, tetrahydroxyethylphosphonium sulfate and the like, but are not restricted only to these exemplified compounds. [0033] Of these exemplified compounds, as the compound represented by the general formula (2) , preferred are a tetramethylammonium salt, a tetraethylammonium salt, a tetrapropylammonaum salt, a tetrabutylammonium salt, a trioctylmethylammonium salt, a tributylbenzylammonium salt, a tetramethylphosphonium salt, a tetraethylphosphonium salt, a tetrapropylphosphonium salt, a tetrabutylphosphonium salt and a methoxymethy1 triphenylphosphonium salt, more preferred are tetraethylammonium chloride, tetrabutylammonium fluoride, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, tetrabutylammonium tetrafluoroborate, trioctylmethylammonium chloride, tributylbenzylammonium chloride, tetrabutylphosphonium chloride, tetrabutylphosphonium bromide and methoxymethyl triphenylphosphonium chloride, and further preferred are tetrabutylammonium chloride, tetrabutylammonium bromide. tetraethylammonium bromide, tetrabutylammonium tetrafluoroborate, trioctylmethylammonium chloride, tributylbenzylammonium chloride, tetrabutylphosphonium chloride and tetrabutylphosphonium bromide. These quaternary ammonium salt compounds and quaternary phosphonium salt compounds may be used singly, or two or more compounds may be used m combination. [0034] In the present invention, the amount of the compound of the general formula (1) without using the compound of the general formula (2) is generally from 0.0005 to b weight parts and preferably from 0.001 to 2 weight parts, based on the total 100 weight parts of one or two or more isocyanates selected from isocyanate compounds and isothiocyanate compounds, and one or two or more active hydrogen compounds each having a mercapto group. The amount used is suitably determined depending on the type of catalysts, the type and amount of monomers (isocyanates, active hydrogen compounds, resin modifiers to be described later or the like) and additives m use, and the shape of molded products. [0035] Furthermore, m the present invention, when the compound of the general formula (1) and the compound of the general formula (2) are used together, the ratio of the compound of the general formula (1) and the compound of the general formula (2) m use is not particularly limited, and any mixing ratio may be good. However, the molar ratio of the compound of the general formula (2) to the compound of the general formula (1) is in the range of 0.01 to 100, preferably m the range of 0.05 to 100, and more preferably in the range of 0.5 to 50 based on the compound of the general formula (1). When the molar ratio of the compound of the general formula (2) IS within the above range, the catalytic activity of the compound of the general formula (1) is rapidly improved, and sufficient dissolution of the compound of the general formula (2) m the polymerizable composition is secured. Therefore, a resin with high transparency can be obtained. [0036] When the compound of the general formula (1) and the compound of the general formula (2) are used together, the amount of the compound of the general formula (1) and the compound of the general formula (2) used may be such that the total amount of the compound of the general formula (1) and the compound of the general formula (2) is m the range of 0.0005 to 5 weight parts, preferably m the range of 0.0010 to 3 weight parts, and more preferably m the range of 0.0010 to 2 weight parts, based on the total 100 weight parts of one or two or more isocyanates selected from isocyanate compounds and isothiocyanate compounds, and one or two or more active hydrogen compounds each having a thiol group. The amount used is suitably determined depending on the type of catalysts, the type and amount of monomers (isocyanates, active hydrogen compounds, resin modifiers to be described later or the like) and additives m use, and the shape of molded products. [0037] A method to add a catalyst to monomers is not particularly limited, and the compound of the general formula (1) and the compound of the general formula (2) may be properly added to monomers, resin modifiers or the like in use. Or, a mixture of the compound of the general formula (1) and the compound of the general formula (2) is obtained, and then the mixture may be added to monomers, resin modifiers or the like. [0038] For example, there can be mentioned a method including adding the compound of the general formula (1) and the compound of the general formula (2) respectively, or adding a mixture of the compound of the general formula (1) and the compound of the general formula (2) to isocyanates, active hydrogen compounds, or a resin modifier such as a hydroxy compound or the like; a method including adding the compound of the general formula (1) and the compound of the general formula (2) respectively, or adding a mixture of the compound of the general formula (1) and the compound of the general formula (2) to a mixture of isocyanates and the active hydrogen compounds; a method including adding the compound of the general formula (1) and the compound of the general formula (2) respectively, or adding a mixture of the compound of the general formula (1) and the compound of the general formula (2) to a mixture of isocyanates and a resin modifier such as a hydroxy compound or the like; a method including adding the compound of the general formula (1) and the compound of the general formula (2) respectively, or adding a mixture of the compound of the general formula (1) and the compound of the general formula (2) to a mixture of active hydrogen compounds and a resin modifier such as a hydroxy compound or the like; and a method including adding the compound of the general formula (1) and the compound of the general formula (2) respectively, or adding a mixture of the compound of the general formula (1) and the compound of the general formula (2) to a mixture of isocyanates, active hydrogen compounds and a resin modifier such as a hydroxy compound or the like, but are not restricted only to these exemplified methods. It can be properly selected depending on the solubility, operability, safety, expediency and the like of a catalyst. [0039] The polymerizable composition for polythiourethane optical materials of the present invention contains one or two or more isocyanates selected from the group consisting of isocyanate compounds and isothiocyanate compounds, and one or two or more active hydrogen compounds each having a mercapto group as main ingredients. However, for the purpose of modification of the polythiourethane resin, a hydroxy compound may further be added. [0040] In the present invention, concrete examples of preferred isocyanate compound which is used as a raw material of the polythiourethane resin include monofunctional isocyanate compounds such as methyl isocyanate, ethyl isocyanate, n-propyl isocyanate, isopropyl isocyanate, n-butyl isocyanate, sec-butyl isocyanate, tert-butyl isocyanate, pentyl isocyanate, hexyl isocyanate, heptyl isocyanate, octyl isocyanate, decyl isocyanate, lauryl isocyanate, myristyl isocyanate, octadecyl isocyanate, 3-pentyl isocyanate, 2-ethylhexyl isocyanate, 2,3-dimethylcyclohexyl isocyanate, 2-methoxyphenyl isocyanate, 4-methoxyphenyl isocyanate, a-methylbenzyl isocyanate. phenylethyl isocyanate, phenyl isocyanate, o-, m-, p-tolyl isocyanate, cyclohexyl isocyanate, benzyl isocyanate, isocyanatomethyl bicycloheptane and the like; aliphatic polyisocyanate compounds such as hexamethylene diisocyanate, 2,2-dimethylpentane diisocyanate, 2,2,4-trimethylhexane diisocyanate, butene diisocyanate, 1,3-butadiene-l,4-diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 1,6,11-undecane triisocyanate, 1,3,6-hexamethylene triisocyanate, 1,8-diisocyanato-4-isocyanatomethyloctane, bis (isocyanatoethyl)carbonate, bis(isocyanatoethyl)ether, lysine diisocyanatomethyl ester, lysine triisocyanate and the 1 i ke ; alicyclic polyisocyanate compounds such as isophorone diisocyanate, l,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, dicyclohexyl dimethylmethane isocyanate, 2,2-dimethyldicyclohexylmethane isocyanate, 2,5-bis(isocyanatomethyl)bicyclo-[2,2,1]-heptane, 2,6-bis(isocyanatomethyl)bicyclo-[2,2, 1]-heptane, 3,8-bis(isocyanatomethyl)tricylcodecane, 3,9-bis(isocyanatomethyl)tricylcodecane, 4,8-bis(isocyanatomethyl)tricylcodecane, 4,9-bis(isocyanatomethyl)tricyclodecane and the like; aromatic polyisocyanate compounds such as o-xylylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, bis(isocyanatoethyl)benzene, bis(isocyanatopropyl)benzene, a,a,a',a'-tetramethylxylylene dxisocyanate, bxs(xsocyanatobutyl)benzene, bxs(xsocyanatomethyl)naphthalene, bis(isocyanatomethyl)dxphenyl ether, phenylene diisocyanate, tolylene diisocyanate, ethylphenylene diisocyanate, isopropylphenylene diisocyanate, dimethylphenyl ene diisocyanate, diethylphenylene diisocyanate, diisopropylphenylene diisocyanate, trimethylbenzene triisocyanate, benzene triisocyanate, biphenyl diisocyanate, toluidme diisocyanate, 4,4-diphenylmethane diisocyanate, 3,3-dimethyldiphenylmethane-4,4-diisocyanate, bibenzyl-4,4-diisocyanate, bis(isocyanatophenyl)ethylene, 3,3-dimethoxybiphenyl-4,4-diisocyanate, phenylisocyanatoethyl isocyanate, hexahydrobenzene diisocyanate, hexahydrodiphenylmethane-4,4-diisocvanate, bis(isocyanatoethyl)phthalate, mesixylylene triisocyanate, 2,6-di(isocyanatomethyl)furan and the like, sulfur-containing aliphatic polyisocyanate compounds such as bis(isocyanatoethyl)sulfide, bis(isocyanatopropyl)sulfide, bis(isocyanatohexyl)sulfide, bis(isocyanatomethyl)sulfone, bis(isocyanatomethyl)disulfide, bis(isocyanatopropyl)disulfide, bis(isocyanatomethylthio)methane, bis(isocyanatoethylthio)methane, bis(isocyanat oethylthio)ethane, bis(isocyanatomethylthio)ethane, 1,5-diisocyanato-2-isocyanatomethyl-3-thiapentane and the like; sulfur-containmg aromatic polyisocyanate compounds such as diphenylsulfide-2,4-diisocyanate, diphenylsulfide-4,4-diisocyanate, 3, 3-dimethoxy-4,4-diisocyanatodibenzylthioether, bis(4-isocyanatomethylbenzene)sulfide, 4,4-methoxybenzenethioethylene glycol-3,3-diisocyanate, 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-S,5-diisocyanate, 3,3-dimethoxydiphenyldisulfide-4,4-diisocyanate, 4,4-dimethoxydiphenyldisulfide-3,3-diisocyanate and the like; and sulfur-containmg heterocyclic polyisocyana-e compounds such as 2,5-diisocyanatothiophene, 2,5-bis(isocyanatomethyl)thiophene, 2,5-diisocyanato tetrahydrothiophene, 2,5-bis(isocyanatomethyl)tetrahydrothiophene, 3,4-bis(isocyanatomethyl)tetrahydrothiophene, 2,5-diisocyanato-l,4-dithiane, 2,5-bis(isocyanatomethyl)-1,4-dithiane, 4,5-diisocyanato-l,3-dithiolane, 4,5-bis(isocyanatomethyl)-1,3-dithiolane, 4,5-bis(isocyanatomethyl)-2-methyl-l,3-dithiolane and the like, but are not restricted only to these exemplified compounds. Their halogen substituted compounds such as chlorine substituted compounds, bromine substituted compounds or the like, alkyl substituted compounds, alkoxy substituted compounds, nitro substituted compounds, prepolymer type modified products modified with polyhydric alcohols, carbodiimide modified products, urea modified products, biuret modified products, d^merization or trimerization reaction products or the like may be employed. These isocyanate compounds may be used singly, or two or more compounds may be used m combination. [0041] In the present invention, an isothiocyanate compound which is used as a raw material of the polythiourethane resm is selected from isothiocyanate compounds and isothiocyanate compounds each having an isocyanate group. Concrete examples of preferred isothiocyanate compound used m the present invention include monofunctional isothiocyanate compounds such as methyl isothiocyanate, ethyl isothiocyanate, n-propyl isothiocyanate, isopropyl isothiocyanate, n-butyl isothiocyanate, sec-butyl isothiocyanate, tert-butyl isothiocyanate, pentyl isothiocyanate, hexyl isothiocyanate, heptyl isothiocyanate, octyl isothiocyanate, decyl isothiocyanate, lauryl isothiocyanate, myristyl isothiocyanate, octadecyl isothiocyanate, 3-pentyl isothiocyanate, 2-ethylhexyl isothiocyanate, 2,3-dimethylcyclohexyl isothiocyanate, 2-methoxyphenyl isothiocyanate, 4-methoxyphenyl isothiocyanate, a-methylbenzyl isothiocyanate, phenylethyl isothiocyanate, phenyl isothiocyanate, o-, m-, p-tolyl isothiocyanate, cyclohexyl isothiocyanate, benzyl isothiocyanate, isothiocyanatomethyl bicycloheptane and the like; aliphatic polyisothiocyanate compounds such as hexamethylene diisothiocyanate, 2,2-dimethylpentane diisothiocyanate, 2,2,4-trimethylhexane diisothiocyanate, butene diisothiocyanate. 1, 3-butadiene-l,4-diisothiocyanate, 2,4,4-trimethylhexamethylene diisothiocyanate, 1,6,11-undecane triisothiocyanate, 1,3,6-hexamethylene triisothiocyanate, 1,8-diisothiocyanato-4-isothiocyanatomethyl octane, bis(isothiocyanatoethyl)carbonate, bis(isothiocyanatoethyl)ether, lysine diisothiocyanatomethyl ester, lysine triisothiocyanate, xylylene diisothiocyanate, bis(isothiocyanatoethyl)benzene, bis(isothiocyanatopropyl)benzene, a,a,a',a'-tetramethylxylylene diisothiocyanate, bis(isothiocyanatobutyl)benzene, bis(isothiocyanatomethyl)naphthalene, bis(isothiocyanatomethyl)diphenyl ether, bis(isothiocyanatoethyl)phthalate, mesitylylene triisothiocyanate, 2,6-di(isothiocyanatomethyl)furan and the 11 ke ; alicyclic polyisothiocyanate compounds such as isophorone diisothiocyanate, bis(isothiocyanatomethyl)cyclohexane, dicyclohexylmethane diisothiocyanate, cyclohe>