Preparation method of isocyanate compounds containing non-chlorinated derivatives and compositions thereof

Abstract

The present invention relates to a method for preparing an isocyanate containing a non-chlorinated derivative, wherein the non-chlorinated derivative is obtained by converting a chlorinated derivative produced in a process of preparing xylylene diisocyanate into a non-chlorinated derivative by a reduction reaction. In particular, the present invention relates to an isocyanate composition containing the non-chlorinated derivative obtained by the reduction reaction and a polymerizable composition containing the same.

Description

Technical Field

[0001] The present invention relates to a method for preparing an isocyanate containing xylylene diisocyanate by converting a chlorinated derivative produced in the process of preparing xylylene diisocyanate into a non-chlorinated derivative by a reduction reaction. In particular, the present invention relates to an isocyanate composition containing xylylene diisocyanate and a very small amount of the chlorinated derivative by converting a chlorinated derivative produced in the process of preparing xylylene diisocyanate into a non-chlorinated derivative by a reduction reaction, and a polymerizable composition containing the same. Background Art

[0002] Xylylene diisocyanate (hereinafter referred to as "XDI") is a very useful compound in the chemical, resin and coating industries as a raw material for polyurethane materials, polyurea materials and polyisocyanate materials. It can be divided into o-xylylene diisocyanate, m-xylylene diisocyanate and p-xylylene diisocyanate according to its structural isomers, among which m-xylylene diisocyanate (hereinafter referred to as "m-XDI" or "1,3-bis(isocyanatomethyl)benzene") accounts for the majority. XDI is a specific diisocyanate with a methylene group on the benzene nucleus, and is an isocyanate with both aromatic and aliphatic isocyanate characteristics. It has the characteristic of suppressing the yellowing phenomenon, which is a disadvantage of aromatic diisocyanates, and is therefore used as a urethane raw material for non-yellowing paints, coatings, leather, adhesives, etc.

[0003] Although various methods for preparing XDI have been proposed in the past, various phosgenation methods have been developed. The phosgenation method is to react an organic primary amine with phosgene in an inert solvent to prepare an isocyanate. In the above method, an aromatic primary amine can be relatively easily converted into a high-purity aromatic isocyanate by passing phosgene through a suspension of a free aromatic amine, a carbonate or a hydrochloride thereof in a solvent.

[0004] However, although XDI contains an aromatic ring, it is classified as an aliphatic isocyanate. When isocyanate is prepared by reacting xylylenediamine with phosgene, many side reactions occur during the reaction, and a large amount of chlorinated derivatives are produced as by-products.

[0005] Korean Patent Gazette No. 1994-0001948 states that the chlorinated derivatives formed when preparing aliphatic isocyanates are usually in an amount of 3 to 10 weight percent, and occasionally up to 20 weight percent. Based on this, when XDI contains chlorinated derivatives, when preparing polyurethane resin from XDI, it will affect the reaction between the isocyanate group and the compound containing active hydrogen, and inhibit the reaction. In addition, it promotes the gelation of the initial polymer, resulting in serious quality effects such as yellowing, turbidity, and streaks.

[0006] On the other hand, the phosgenation method can be divided into a direct method in which the raw material amine is directly reacted with phosgene and a hydrochloride method in which the raw material amine is prepared as a hydrochloride and then reacted with phosgene. Although the direct method is much more convenient than the hydrochloride method, it is generally not used because a large amount of chlorinated derivatives are produced. Due to the above reasons, in the case of preparing linear or cyclic aliphatic isocyanates, the hydrochloride method is used to prepare isocyanates by preparing the raw material amine as a hydrochloride and then reacting with phosgene. However, even in the hydrochloride method, a certain amount of chlorinated derivatives are produced, and therefore, a method for obtaining high-purity XDI by reducing the impurity content is also disclosed.

[0007] In Korean Patent No. 10-0953019, a high pressure is applied during the reaction step of generating a salt by a method for preparing isocyanate from a linear or cyclic aliphatic amine (a step of obtaining a slurry containing amine hydrochloride) to suppress the increase in the hydrochloride particle size. In addition, the hydrochloride viscosity is reduced due to the refinement of the hydrochloride particles, thereby improving the fluidity and liquid transferability, thereby increasing the yield by increasing the hydrochloride conversion rate during phosgenation and reducing the generated chlorinated derivatives to 0.1% to 0.3% by weight.

[0008] Furthermore, the optical material resin obtained from the XDI composition in which the concentration of the compound of the chemical formula (5) as a chlorinated derivative is greater than or equal to 0.2ppm and less than 600ppm disclosed in Korean Patent Publication No. 2018-0104330 has excellent yellowing resistance and high production efficiency. In addition, Korean Patent Publication No. 2018-0127517 also discloses that the compound of the chemical formula (7) in the chlorinated derivative should have excellent discoloration resistance below 60ppm. However, the main impurity chlorinated derivative produced in such an isocyanate synthesis reaction plays the role of an impurity that adversely affects the physical properties of the optical lens in the application of the polyurethane reaction. It is judged that the content of these impurities causes yellowing and has an adverse effect on the product, so these chlorinated derivatives should not be produced, or even if they are produced, they must be removed by purification and other means. The above-mentioned prior art has the problem that all processes need to be precisely controlled and high-level distillation towers are used for separation and purification. Therefore, the competitiveness is reduced due to the increase in equipment costs, which reduces the possibility of industrialization.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Korean Patent Gazette No. 1994-0001948 (granted on March 12, 1994)

[0012] Patent Document 2: Korean Patent No. 0953019 (granted on April 7, 2010)

[0013] Patent Document 3: Korean Patent Publication No. 2018-0104330 (published on September 20, 2018)

[0014] Patent Document 4: Korean Patent Publication No. 2018-0127517 (published on November 28, 2018) Summary of the invention

[0015] Technical issues

[0016] Therefore, the object of the present invention is to prepare isocyanate by simplifying the process by converting the chlorinated derivatives produced in the conventional process into non-chlorinated derivatives through a simple reduction reaction without performing the above-mentioned complicated process for reducing the chlorinated derivatives.

[0017] Among them, the non-chlorinated derivatives formed by the reduction reaction have excellent yellowing resistance even if they are contained in the resin, and can also improve the physical properties of the general resin. Compared with XDI, the boiling point can be further reduced to 60 to 75°C, so separation and purification can be said to be simpler. Usually, in order to inhibit the formation of chlorinated derivatives, it is necessary to hydrochloride the amine, perform a high-pressure reaction in the salt-forming process, and perform separation and purification by precise control. However, in the present invention, even in the direct method process where it is difficult to control the chlorinated derivatives, the separation and purification can be simplified by a simple reduction reaction, thereby having economic benefits, and therefore can be different from the general process. Therefore, the present invention can have economic benefits in industrialization by reducing process costs, obtaining high yields, and obtaining high-quality products.

[0018] Technical Solution

[0019] In order to achieve the purpose of the present invention, one embodiment of the present invention provides a method for preparing isocyanate, characterized in that the above-mentioned isocyanate contains a non-chlorinated derivative, and the above-mentioned non-chlorinated derivative is obtained by converting the chlorinated derivative represented by chemical formula (1) produced in the preparation process of xylene diisocyanate into a non-chlorinated derivative through a reduction reaction.

[0020] Chemical formula (1)

[0021]

[0022] Among them, R1 is Cl or NCO, and R2 is H or Cl.

[0023] The xylylene diisocyanate of the present invention can be obtained by directly reacting an organic primary amine with a carbonylating agent in an inert solvent according to the following reaction formula.

[0024]

[0025] Furthermore, the xylylene diisocyanate of the present invention is obtained by a method comprising the following steps: a first step of reacting an organic primary amine with hydrogen chloride gas according to the following reaction formula; and a second step of reacting the amine hydrochloride produced in the first step with a carbonylating agent.

[0026] Step 1

[0027]

[0028] Step 2

[0029]

[0030] The carbonylating agent used in the present invention may be selected from phosgene, diphosgene, triphosgene, alkyl chloroformate or a combination thereof. Also, the chlorinated derivative may be one or more chlorinated derivatives represented by the following chemical formula (2).

[0031] Chemical formula (2)

[0032]

[0033] R1 is Cl or NCO, and R2 is H or Cl.

[0034] Furthermore, the non-chlorinated derivative may be one or more non-chlorinated derivatives represented by the following chemical formula (3).

[0035] Chemical formula (3)

[0036]

[0037] R3 is H or NCO.

[0038] On the other hand, the reduction reaction of the present invention can be carried out in a hydrogen (H2) atmosphere using a metal catalyst or a reducing agent, wherein the metal catalyst used can be one or more of palladium, platinum and nickel, preferably palladium or platinum. In addition, the reducing agent used can be selected from lithium aluminum hydride (LiAlH4), sodium amalgam (Na(Hg)), zinc amalgam (Zn(Hg)), diborane (B2H6), lithium borohydride (LiBH4), sodium borohydride (NaBH4), ferrous sulfate (FeSO4), stannous chloride (SnCl2), sodium dithionite (Na2S2O6), sodium thiosulfate (Na2S2O3), ammonium thiosulfate ((NH4)2S2O3), diisobutyl hydride Aluminum (DIBAL-H), oxalic acid (C2H2O4), formic acid (HCOOH), dithiothreitol (DTT), tri-2-carboxyethylphosphine hydrochloride (TCEP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), butylated hydroxytoluene (BHT), 2,6-di-tert-butyl-4-methylphenol and 2,4-dimethyl-6-tert-butylphenol, metallic hydrides such as trialkyltin hydride and tributyltin hydride, and one or more metals such as zinc.

[0039] In order to achieve the additional purpose of the present invention, another embodiment of the present invention provides an isocyanate composition, characterized in that it is an isocyanate composition containing xylylenediisocyanate (XDI) as a main component, and further contains methylbenzyl isocyanate represented by chemical formula (4) as a non-chlorinated derivative obtained by the above-mentioned preparation method.

[0040] Chemical formula (4)

[0041]

[0042] Furthermore, the isocyanate composition of the present invention may further include a chlorinated derivative represented by the above chemical formula (1). Furthermore, the above chlorinated derivative is a chlorinated derivative represented by the above chemical formula (2), and may further include one or more of chloromethyl benzyl isocyanate, bis(chloromethyl)benzene, dichloromethyl benzyl isocyanate, and chloromethyl dichloromethyl benzene.

[0043] Chemical formula (2)

[0044]

[0045] R1 is Cl or NCO, and R2 is H or Cl.

[0046] Furthermore, the isocyanate composition of the present invention may contain non-chlorinated derivatives in the range of 0.1ppm to 50000ppm, and may contain chlorinated derivatives in the range of greater than 0ppm and less than or equal to 1500ppm. Furthermore, in the isocyanate composition of the present invention, when the isocyanate is xylylene diisocyanate (XDI), in consideration of various properties of optical lenses, preferably, it may contain 99 mass percent or more.

[0047] Furthermore, in order to achieve the additional object of the present invention, another embodiment of the present invention provides a polymerizable composition consisting of the above-mentioned isocyanate composition and a compound containing one or more isocyanate-reactive functional groups. The compound containing one or more isocyanate-reactive functional groups used may be a polyol compound or a polythiol compound, and such a polymerizable composition may be used as a coating material.

[0048] Furthermore, in order to achieve the additional object of the present invention, another embodiment of the present invention provides a resin obtained by reacting the above-mentioned polymerizable composition. Such a resin can be used as an optical material including an optical lens.

[0049] On the other hand, another embodiment of the present invention can also provide an isocyanate composition containing xylylene diisocyanate as a main component, wherein the above-mentioned xylylene diisocyanate also contains a non-chlorinated derivative obtained by a separate synthesis rather than by a reduction reaction of the above-mentioned chlorinated derivative, that is, methylbenzyl isocyanate represented by the above-mentioned chemical formula (4).

[0050] As described above, such an isocyanate composition may further include one or more of the chlorinated derivatives represented by the above chemical formula (2). Preferably, the isocyanate composition may include a non-chlorinated derivative in a range of 0.1 ppm to 50,000 ppm, and may include a non-chlorinated derivative in a range of greater than 0 ppm and less than or equal to 1,500 ppm.

[0051] Effects of the Invention

[0052] The preparation method of the present invention makes it possible to improve the preparation efficiency and quality of isocyanates widely used in the chemical, resin and coating industry fields including the optical material field, and therefore has high technical and industrial value.

[0053] The isocyanate composition containing non-chlorinated derivatives obtained through the reduction process of the present invention has excellent economic efficiency and is convenient for reducing chlorinated derivatives. In addition, the method can be used to obtain optical resins or optical products of excellent quality with high economic efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1The present invention is a graph showing the gas chromatography (GC) results of the product of Example 3 before the reduction reaction of Preparation Example 3 (Part (A)) and after the reduction reaction (Part (B)) and before desolvation in the process of converting a chlorinated derivative into a non-chlorinated derivative by a simple reduction reaction. DETAILED DESCRIPTION

[0055] definition

[0056] Unless otherwise defined, all technical and scientific terms used in the description of the present invention have the same meanings as understood by those of ordinary skill in the art to which the present invention belongs. The full texts of all patent publications, application publications and other publications cited as prior art are incorporated herein by reference.

[0057] The "isocyanate" used in the description of the present invention is a substance used as a polyurethane material or a polyurea material, and is used in the synthesis of the above materials having different structures according to the number and position of the functional groups. The "isocyanate" is used to include monoisocyanate, diisocyanate or polyisocyanate.

[0058] The term "chlorinated derivative" is generated when preparing isocyanate by a direct method, a hydrochloride method or a carbonate method, and refers to an impurity containing chlorine generated by a side reaction at this time. In the present invention, the chlorinated impurity includes 3-chloromethylbenzyl isocyanate (chemical formula (5)), 1,3-dichlorobenzyl (chemical formula (6)), 3-dichloromethylbenzyl isocyanate (chemical formula (7)), etc.

[0059]

[0060] The term "non-chlorinated derivative" refers to a substance obtained by removing chlorine from the above-mentioned "chlorinated derivative" by substitution with other atoms or atomic groups through a reduction reaction. In the present invention, non-chlorinated impurities include methylbenzyl isocyanate, xylene, and the like.

[0061] Furthermore, the term "isocyanate-reactive functional group" refers to a "component containing an active hydrogen group" that reacts with isocyanate, for example, a polyol component (a main component contained in a polyol having two or more hydroxyl groups), a polythiol component (a main component contained in a polythiol having two or more mercapto groups), a polyamine (a main component contained in a polyamine having two or more amino groups), etc.

[0062] The term "carbonylation agent" refers to a reagent that causes a carbonylation reaction, which is a reaction for introducing carbon monoxide into an organic compound or the like. Carbonylation produces organic carbonyl compounds, i.e., compounds containing a >C=O functional group, such as aldehydes, ketones, carboxylic acids, and esters. In particular, organic compounds containing carbonyl groups have unsaturated bonds, are rich in reactivity, and can be highly selective reactions, and therefore are also widely used in synthetic chemistry. Representative carbonylation agents used in the present invention may be phosgene, diphosgene, triphosgene, alkyl chloroformate compounds, and the like.

[0063] The term "combination" as used herein is inclusive of fusions, mixtures, reaction products, and the like.

[0064] Furthermore, specific numerical values ​​such as the mixing ratio (content ratio), physical property values, and parameters described in the present invention may be replaced by the upper limit value (the value defined by "below" or "less than") or the lower limit value (the value defined by "above" or "greater than") of the corresponding mixing ratio (content ratio), physical property values, and parameters. On the other hand, "%" is based on mass unless otherwise specified.

[0065] Unless the context clearly indicates otherwise, the singular forms used in the description and claims of the present invention include the plural referents. Thus, for example, reference to "isocyanate" includes mixtures of two or more monoisocyanates, diisocyanates, and polyisocyanates.

[0066] Unless otherwise specified, the materials described in the description of the present invention are all commercially available, and their production methods are well known to those skilled in the art to which the present invention belongs. In addition, unless otherwise specified, all test standards in the description of the present invention are the latest standards effective at the time of filing this application.

[0067] Hereinafter, the method for producing the isocyanate and the composition of the present invention will be described in detail.

[0068] First, the present invention converts the chlorinated derivatives produced in the preparation process of isocyanate into non-chlorinated derivatives through the reduction reaction of the following reaction formula, without going through a high-level purification process, thereby easily improving the purity of isocyanate.

[0069]

[0070] R1 is Cl or NCO, and R2 is H or Cl.

[0071]

[0072] R3 is H or NCO.

[0073] As described above, since a certain amount of a chlorinated derivative of a compound known as Chemical Formula 5 is also produced in the hydrochloride method as in the direct method, it can be used to obtain XDI constituting the isocyanate composition of the present invention.

[0074] XDI includes structural isomers 1,2-XDI (ortho-form), 1,3-XDI (meta-form), and 1,4-XDI (para-form), and they can be used alone or in combination of two or more. 1,3-XDI or 1,4-XDI is preferred, and 1,3-XDI is more preferred.

[0075] Since the isocyanate composition obtained by the production method of the present invention is used as a reactant for obtaining a polymer compound such as polyurethane, the aliphatic amine used in the present invention is preferably a bifunctional or higher-functional linear or cyclic aliphatic amine.

[0076] The preferred bifunctional or higher chain or cyclic aliphatic amine used in the present invention is not particularly limited, but the contents mentioned in the above-mentioned prior art document No. 10-0953019 can be referred to. Representative examples include chain aliphatic amines such as hexamethylenediamine, 2,2-dimethylpentanediamine, 2,2,4-trimethylhexanediamine, butanediamine, and xylylenediamine, and cyclic aliphatic amines such as bis(aminomethyl)cyclohexane, dicyclohexylmethanediamine, cyclohexanediamine, and bis(aminomethyl)norbornane.

[0077] The isocyanate obtained by reacting the above-mentioned chain or cyclic aliphatic diamine with phosgene is determined by the diamine to be reacted, and the contents mentioned in the above-mentioned prior art document No. 10-0953019 can be referred to. Representative examples thereof include chain aliphatic isocyanates such as hexamethylene diisocyanate, 2,2-dimethylpentamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, butane diisocyanate, and xylyl diisocyanate, and cyclic aliphatic isocyanates such as bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane diisocyanate, cyclohexane diisocyanate, and bis(isocyanatomethyl)norbornane. Among the above-mentioned exemplary compounds obtained by the preparation method of the present invention, compounds particularly preferred in various optical device applications may be xylyl diisocyanate, bis(isocyanatomethyl)norbornane, hexamethylene diisocyanate, and bis(isocyanatomethyl)cyclohexane.

[0078] The carbonylating agents that can be used in the preparation of XDI of the present invention are phosgene, diphosgene, triphosgene and various alkyl chloroformate compounds, which can be used alone or in combination of two.

[0079] Phosgene gas that can be used in the preparation of the benzyl diisocyanate of the present invention is the common name of carbonyl chloride or carbonyl dichloride (COCl2), which is a colorless gas at room temperature, has a condensation point of 127.84°C, and a boiling point of 7.84°C. It is usually produced by the catalyst reaction of anhydrous chlorine and high-purity carbon monoxide. The phosgene substitute and / or precursor used in the present invention may include any phosgene equivalents such as diphosgene and triphosgene, and any coordination compounds thereof. The phosgene used in the present invention can be provided by thermal decomposition of a carbamic acid derivative using chloroformate, diphenyl carbamate or N,N'-carbonyl diimidazole.

[0080] On the other hand, the isocyanate composition of the present invention can contain a small amount of non-chlorinated derivatives by converting the chlorinated derivative represented by the chemical formula (1) produced in the process of preparing XDI into non-chlorinated derivatives through a reduction reaction using a catalyst or a reducing agent, followed by filtration and purification.

[0081] Chemical formula (1)

[0082]

[0083] Among them, R1 is Cl or NCO, and R2 is H or Cl.

[0084] Among them, the chlorinated derivatives contained in XDI include 3-chloromethylbenzyl isocyanate (chemical formula (5)), 1,3-dichlorobenzyl (chemical formula (6)), 3-dichloromethylbenzyl isocyanate (chemical formula (7)), etc., and can exist alone or in combination of two or more.

[0085] On the other hand, the non-chlorinated derivative is methylbenzyl isocyanate (chemical formula (4)) or xylene. The compound of the chemical formula (4) of the present invention includes the structural isomers 1,2-methylbenzyl isocyanate, 1,3-methylbenzyl isocyanate, and 1,4-methylbenzyl isocyanate, as are the structural isomers of XDI, and can exist alone or in two or more forms, preferably 1,3-methylbenzyl isocyanate and 1,4-methylbenzyl isocyanate, and more preferably 1,3-methylbenzyl isocyanate. Furthermore, xylene also includes the structural isomers 1,2-xylene, 1,3-xylene, and 1,4-xylene, and can exist alone or in two or more forms, preferably 1,3-xylene and 1,4-xylene, and more preferably 1,3-xylene.

[0086] The XDI composition of the present invention may contain methylbenzyl isocyanate. If the content of methylbenzyl isocyanate is greater than 50,000 ppm relative to the total mass of the XDI composition, the physical properties of the lens such as heat resistance are reduced. Therefore, preferably, the content is greater than 0.1 ppm and less than 50,000 ppm. In addition, after conversion to methylbenzyl isocyanate, a trace amount of chlorinated derivatives may remain. In the presence of methylbenzyl isocyanate, if the content of the chlorinated derivatives is greater than 1500 ppm, the yellowness index of the lens is high. Therefore, preferably, the content of the chlorinated derivatives is greater than 0 ppm and less than or equal to 1500 ppm relative to the total mass of the XDI composition.

[0087] On the other hand, the reduction reaction of the present invention is a dechlorination reaction by hydrogenation reaction, which can be divided into a reduction step using a metal catalyst in a hydrogen atmosphere and a reduction step using a reducing agent, which can be performed separately or in parallel. Preferably, it can be a reduction step using a noble metal catalyst in a hydrogen atmosphere.

[0088] The temperature of the reduction process is not particularly limited, and the reduction process may be carried out at a temperature of 0°C to 180°C, preferably at a temperature of 10°C to 150°C, and more preferably at a temperature of 20°C to 50°C. Furthermore, the pressure of the reduction process is not particularly limited, and may be 0.001 kgf / cm 2 ~200kgf / cm 2 Preferably, it can be carried out at 0.1kgf / cm 2 ~10kgf / cm 2 More preferably, it can be carried out at 1kgf / cm 2 ~5kgf / cm 2 Next proceed.

[0089] In addition, the catalyst used in the reduction process is not particularly limited, and a noble metal or transition metal catalyst can be used, and two or more thereof can be used alone or in combination. The metal catalyst can be palladium (Pd), platinum (Pt), ruthenium (Ru), nickel (Ni), etc. alone, or supported on metal oxides such as activated carbon, silicon dioxide (SiO2), aluminum oxide (Al2O3), cerium oxide (CeO2), zirconium dioxide (ZrO2), etc., and a metal ligand can also be used alone or in combination. The amount of catalyst in the reduction process is not particularly limited, and can be carried out at a content of more than 0.1% to less than 20% relative to the total mass of XDI, preferably, at a content of 0.3% to 15%, and more preferably, at a content of 0.5% to 5%. Furthermore, the reducing agent may be one or more selected from the group consisting of lithium aluminum hydride, sodium amalgam, zinc amalgam, diborane, lithium borohydride, sodium borohydride, ferrous sulfate, stannous chloride, sodium dithionite, sodium thiosulfate, ammonium thiosulfate, diisobutylaluminum hydride, oxalic acid, formic acid, dithiothreitol, tri-2-carboxyethylphosphine hydrochloride, 2,2-diphenyl-1-picrylhydrazyl, butylhydroxytoluene, 2,6-di-tert-butyl-4-methylphenol and 2,4-dimethyl-6-tert-butylphenol, trialkyltin hydride, tributyltin hydride and other metal hydrides, and metals such as zinc. Preferably, it may be a palladium / carbon (C) catalyst.

[0090] In order to exclude oxygen in the reduction process of the present invention, it is preferably carried out in a nitrogen atmosphere or a hydrogen atmosphere. For chlorinated derivatives, it can be carried out in a solvent or in a state where the solvent is removed. The solvent used in the present invention is not particularly limited. The inert solvent can be, for example, aromatic hydrocarbons such as benzene and toluene, aliphatic hydrocarbons such as octane and decane, alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, and ethylcyclohexane, halogenated aromatic hydrocarbons such as chlorotoluene, chlorobenzene, dichlorobenzene, dibromobenzene, and trichlorobenzene, nitrobenzene, N,N-dimethylformamide, N,N-dimethylacetamide, N,N'-dimethylimidazolidinone and other nitrogen-containing compounds, ethers such as dibutyl ether, ethylene glycol dimethyl ether, and ethylene glycol diethyl ether, amyl formate, n-butyl acetate, isobutyl acetate, n-amyl acetate, ethyl acetate, etc. Fatty acid esters such as isopentyl acetate, methyl isopentyl acetate, methoxybutyl acetate, 2-ethoxyethyl acetate, secondary hexyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, benzyl acetate, ethyl propionate, n-butyl propionate, isopentyl propionate, ethyl acetate, butyl stearate, butyl lactate and amyl lactate, and aromatic carboxylic acid esters such as methyl salicylate, dimethyl phthalate and methyl benzoate, etc., can be used alone or in combination of two or more. Preferably, it can be halogenated aromatic hydrocarbons, more preferably, it can be chlorophenyl dichlorobenzene.

[0091] Furthermore, after filtering the solvent or reducing agent used in the reduction process of the present invention, the chlorinated derivative and the non-chlorinated derivative can be adjusted by simple distillation purification, etc. Of course, such a reduction process can also be applied to the preparation of isocyanates containing XDI and chlorinated derivatives, after desolventization, and after purification.

[0092] Therefore, the isocyanate composition obtained by the above process can have sufficiently high optical properties and can be used in the preparation of optical materials, specifically, can be used in the preparation of plastic optical lenses.

[0093] According to the present invention, there is provided a polymerizable composition comprising the above-described isocyanate composition and a polyol / polythiol.

[0094] The polymerizable composition may contain the isocyanate composition and the polyol / polythiol in a mixed state or in a separated state. That is, in the polymerizable composition, the isocyanate composition and the polyol / polythiol may be in a contacting state or in a separated state without contacting each other.

[0095] The polyol component used in the polymerizable composition of the present invention may be, for example, a low molecular weight polyol or a high molecular weight polyol. These polyols may be used alone or in combination of two or more.

[0096] The low molecular weight polyol is a compound having two or more hydroxyl groups and having a number average molecular weight of 60 or more and less than 400. The low molecular weight polyol may be, for example, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol and a mixture thereof, diols such as 1,4-cyclohexanediol, hydrogenated bisphenol A, bisphenol A, triols such as glycerol, tetraols such as tetrahydroxymethylmethane (pentaerythritol), pentaols such as xylitol, and hexaols such as sorbitol, mannitol, allitol, and iditol.

[0097] The high molecular weight polyol is a compound having two or more hydroxyl groups and a number average molecular weight of 400 or more, for example, a compound having two or more hydroxyl groups and a number average molecular weight of 10,000 or less, preferably, a compound having two or more hydroxyl groups and a number average molecular weight of 5,000 or less. The high molecular weight polyol may be, for example, polyether polyol, polyester polyol, polycarbonate polyol, polyurethane polyol, epoxy polyol, vegetable oil polyol, polyolefin polyol, polyacrylic polyol, silicon polyol, fluorine polyol, and polyol modified with vinyl monomers.

[0098] The polythiol component used in the polymerizable composition of the present invention may be, for example, an aliphatic polythiol, an aromatic polythiol, a heterocyclic polythiol, an aliphatic polythiol containing a sulfur atom other than a mercapto group, an aromatic polythiol containing a sulfur atom other than a mercapto group, a heterocyclic polythiol containing a sulfur atom other than a mercapto group, etc. The above-mentioned thiol may be a thiol oligomer or a polythiol, and may be used alone or in combination of two or more. Specific examples of the above-mentioned thiols include 3,3'-thiobis[(2-mercaptoethyl)thio]-1-propanethiol, bis(2-(2-mercaptoethylthio)-3-mercaptopropyl) sulfide, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 2,3-bis(2-mercaptoethylthio)propane-1-thiol, 2,2-bis(mercaptomethyl)-1,3-propanedithiol, bis(2-mercaptoethyl) sulfide, tetrakis(mercaptomethyl)methane, 2-(2-mercaptoethylthio)propane-1,3-dithiol, 2-(2,3-bis(2-mercaptoethylthio)propylthio)ethanethiol, bis(2,3 1,2-bis[(2-mercaptoethyl)thio]-3-mercaptopropane, 1,2-bis(2-(2-mercaptoethylthio)-3-mercaptopropylthio)ethane, 2-(2-mercaptoethylthio)-3-[3-mercapto-2-(2-mercaptoethylthio)-propylthio]propylthio-propane-1-thiol, 2,2-bis-(3-mercapto-propionyloxymethyl)-butyl ester, 2-(2-mercaptoethylthio)-3-(2-(2-mercaptoethylthio)-propylthio]ethylthio (S)-3-((R-2,3-dimercaptopropyl)thio)propane-1,2-dithiol, (4R,14R)-4,14-bis(mercaptomethyl)-3,6,9,12,15-pentathiaheptane-1,17-dithiol, (S)-3-((R-3-mercapto-2-((2-mercaptoethyl)thio)propyl)thio)-2-((2-mercaptoethyl)thio)propane-1-thiol, 3,3'-dimercaptopropyl)thio)propane-1,2-dithiol, (4R,14R)-4,14-bis(thio)methyl-3,6,9,12,15-pentathiaheptane-1,17-dithiol, (S)-3-((R-3-mercapto-2-((2-mercaptoethyl)thio)propyl)thio)-2-((2-mercaptoethyl)thio)propane-1-thiol, Thiobis(propane-1,2-dithiol), (7R,11S)-7,11-bis(mercaptomethyl)-3,6,9,12,15-pentathiaheptadecane-1,17-dithiol, (7R,12S)-7,12-bis(mercaptomethyl)-3,6,9,10,13,16-hexathiaoctadecane-1,18-dithiol, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, pentaerythritol tetrakis (3-mercaptopropionate), trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (2-mercaptoacetate), dipentaerythritol ether hexakis (3-mercaptopropionate), 1,1,3,3-tetrakis (mercaptomethylthio) propane, 1,1,2,2-tetrakis (mercaptomethylthio) ethane, 4,6-bis (mercaptomethylthio)-1,3-dithiane, pentaerythritol tetrakis (2-mercaptoacetate), pentaerythritol tetrakis (3-mercaptopropionate), 2-(2,2-bis (mercaptodimethylthio) ethyl)-1,3-dithiane, etc.

[0099] In addition to the above components, the polymerizable composition may further contain additives such as internal release agents, ultraviolet absorbers, near infrared absorbers, polymerization initiators, heat stabilizers, color correctors, chain extenders, crosslinking agents, light stabilizers, antioxidants, fillers, etc. as needed.

[0100] The internal release agent can be used alone or in combination of two or more selected from the following components: fluorine-based nonionic surfactants with perfluoroalkyl, hydroxyalkyl or phosphate groups; silicon-based nonionic surfactants with dimethyl polysiloxane groups, hydroxyalkyl or phosphate groups; alkyl quaternary ammonium salts, i.e., trimethyl hexadecyl ammonium salt, trimethyl stearic acid ammonium salt, dimethyl ethyl hexadecyl ammonium salt, triethyl dodecyl ammonium salt, diethyl cyclohexadecyl ammonium salt; acidic phosphate. The above components can be used alone or in combination of two or more.

[0101] As the ultraviolet absorber, benzophenone, benzotriazole, triazine, salicylate, cyanoacrylate, oxalic acid anilide and the like can be used.

[0102] The above-mentioned near infrared absorber can use azo, amine, anthraquinone, cyanine, polymethine, diphenylmethane, triphenylmethane, quinone, dimethylammonium, dithiol metal complex, square acid, phthalocyanine, naphthalocyanine. In particular, as one of the electromagnetic wave absorbers, a near infrared absorber with a high near infrared absorption capacity of more than 30% blocking rate near the wavelength of 800nm ​​to 1000nm can be used. Such a near infrared absorber is a mixture of a plurality of phthalocyanine pigments with different structures, preferably, these pigments are respectively pigments with a minimum value of a light transmittance curve of less than 80% transmittance in the range of (i) 800nm ​​to 850nm wavelength region, (ii) 875nm to 925nm wavelength region and (iii) 950nm to 1000nm wavelength region. For example, PANAX FND-83, PANAX FND-88, PANAX FND-96, etc. can be used.

[0103] As the polymerization initiator, amines, phosphorus, organic tin, organic copper, organic gallium, organic zirconium, organic iron, organic zinc, organic aluminum, organic bismuth, etc. can be used.

[0104] The heat stabilizer may be a metal fatty acid salt, a phosphorus salt, a lead salt, an organic tin salt, or the like, alone or in combination of two or more.

[0105] Furthermore, according to the present invention, there is provided a polythiourethane obtained from the polymerizable composition described above. That is, the polythiourethane can be prepared by polymerizing (and curing) an isocyanate composition and a thiol in the polymerizable composition. The polymerization reaction can make the molar ratio of thiol (SH) group / isocyanate (NCO) group be 0.5 to 3.0, more specifically, 0.8 to 1.3.

[0106] Furthermore, in order to adjust the reaction rate, a reaction catalyst commonly used in the preparation of polythiourethane may be added. The curing catalyst (polymerization initiator) may be a tin catalyst, for example, dibutyltin dichloride, dibutyltin dilaurate, dimethyltin dichloride, etc.

[0107] Hereinafter, various methods for detecting physical properties including the characteristics of standard substances of isocyanate and the content thereof will be described.

[0108] Analytical methods

[0109] (1) Content of 1,3-phenylenediisocyanate (XDI)

[0110] XDI with a purity of 99% prepared in the preparation example described later was used as a standard substance, and the analysis was performed by gas chromatography under the following conditions. A calibration curve was drawn based on the area values ​​of the obtained gas chromatograms to obtain the quantitative results.

[0111] - Equipment: HP-6890 (HP)

[0112] -Chromatographic column: DB-1 (inner diameter 0.53mm×length 60m×thickness 1.5μm)

[0113] -Injection port temperature: 180℃

[0114] -Testing instrument temperature: 300℃

[0115] (2) Content of 3-chloromethylbenzyl isocyanate (chemical formula (5))

[0116] The content of the compound of the chemical formula (5) in the compositions of the examples and comparative examples was calculated by the same method as the above-mentioned XDI determination method, using the compound of the chemical formula (5) having a purity of 99% separated / purified by column distillation as a standard substance in the XDI composition prepared in the preparation example.

[0117] By carbon 13 nuclear magnetic resonance ( 13 The obtained compound of the chemical formula (5) was analyzed by C-NMR) (100 MHz, deuterated chloroform (CDCl 3 )), Fourier transform infrared spectroscopy (FT-IR) and mass spectrometry (MS).

[0118] 13 C-NMR (100MHz, CDCl3) δ46.5,54.6,125.6,127.9,128.8,130.5,139.9,139.1

[0119] FT-IR: 2260cm -1

[0120] MS: m / z = 181 (M+)

[0121] (3) Content of 1,3-dichlorobenzyl (chemical formula (6))

[0122] The content of the compound of chemical formula (6) in the compositions of each example and comparative example was calculated by using the same method as the above-mentioned XDI detection method, using the compound of chemical formula (6) with a purity of 98% (reagent, Sigma-Aldrich) as a standard substance.

[0123] (4) Content of dichloromethylbenzyl isocyanate (chemical formula (7))

[0124] The compound of the chemical formula (7) with a purity of 99 mol% prepared by the method disclosed in Korean Patent Publication No. 2018-0127517 was used as a standard substance, and analyzed by gas chromatography under the following conditions, and a calibration curve was drawn using the area value of the obtained gas chromatogram for quantification.

[0125] - Equipment: HP-6890 (HP)

[0126] -Chromatographic column: HP-50+ (inner diameter 0.25mm×length 30m×thickness 0.25μm)

[0127] -Testing instrument temperature: 280℃

[0128] The obtained compound of the chemical formula (7) was analyzed by C13 NMR (100 MHz, deuterated chloroform), Fourier transform infrared spectroscopy, and mass spectrometry.

[0129] 13 C-NMR (100MHz, CDCl3) δ46.3,72.5,122.9,127.8,128.7,129.1,139.0,140.3

[0130] FT-IR:2260cm -1

[0131] MS: m / z = 215 (M+)

[0132] (5) Content of 3-methylbenzyl isocyanate (compound of chemical formula (4))

[0133] The content of methylbenzyl isocyanate in the composition of each example and comparative example was calculated by using methylbenzyl isocyanate (reagent, Sigma-Aldrich) with a purity of 98% as a standard substance in the same manner as the above-mentioned XDI detection method.

[0134] (6) Refractive index of optical lenses

[0135] The refractive index (n) of the optical lens obtained by the composition of each embodiment and comparative example described below at a wavelength of 546.1 nm (mercury e-line) was measured at a temperature of 20°C using a DR-M4 refractometer produced by ATAGO. e ).

[0136] (7) Evaluation of heat resistance of optical lenses

[0137] The glass transition temperature (Tg) was measured using a differential scanning calorimeter DSC N-650. The glass transition temperature was used as an index of heat resistance.

[0138] (8) Yellow Index (YI) and light transmittance of optical lenses

[0139] The yellowness index of the optical lens was calculated using Formula 1 by calculating the chromaticity coordinates x and y using UV-2600 240V EN (Shimadzu Corporation).

[0140] Mathematical formula 1

[0141] Yellowness index (YI) = (234x + 106y + 106) / y

[0142] (9) Evaluation of the dyeability (colorability) of optical lenses

[0143] After preparing a Gray BPI#32000 (dye) dye dispersion, a resin having a thickness of 2.0 mm was immersed in the dispersion in a water bath at 95° C. for 5 minutes to dye. The light transmittance (%) of the dyed resin in the entire wavelength range of visible light (380 nm to 780 nm) was measured.

[0144] According to the degree of dyeing, the dye absorbs light, and the lower the transmittance at each wavelength, the better the dyeing property.

[0145] (10) Turbidity of optical lenses

[0146] The haze of the optical lens was evaluated by naked eyes according to the following criteria.

[0147] Good: transparent; bad: turbid

[0148] (11) Texture of optical lenses

[0149] When observing an optical lens under a mercury lamp, if unevenness is confirmed, it is classified as having texture.

[0150] Although the present invention is illustrated by the following examples, the present invention is not limited to the following examples. First, in the preparation method of the present invention, the process of preparing XDI under various conditions was observed by changing the reaction conditions.

[0151] Example

[0152] 1. Synthesis of 1,3-phenylenediisocyanate (XDI) and preparation of XDI compositions containing chlorinated derivatives

[0153] Synthesis example 1

[0154] After dissolving 7.3 kg of bis(trichloromethyl)carbonate in 36 kg of o-dichlorobenzene in a 50 L reaction vessel equipped with a reflux cooler, slowly add a solution of 2 kg of m-xylylenediamine dissolved in 2 kg of o-dichlorobenzene at a temperature below 60°C. After raising the temperature to 160°C, react for 4 hours while controlling the release of hydrogen chloride gas. While heating, slowly add a solution of bis(trichloromethyl)carbonate dissolved in o-dichlorobenzene and stir smoothly. After the reaction is completed, purge the nitrogen in the reactor to remove unreacted phosgene and hydrogen chloride gas, and filter the solution to obtain XDI containing chlorinated derivatives. In the XDI solution other than o-dichlorobenzene, the content of chlorinated derivatives is about 2.8%.

[0155] Synthesis example 2

[0156] After desolventizing the solution obtained in Synthesis Example 1, pure XDI containing no chlorinated derivatives was obtained by high vacuum distillation.

[0157] Preparation Example 1 to Preparation Example 3

[0158] Chlorinated derivatives (compounds of formula (5), formula (6), and formula (7) were mixed at a predetermined ratio) as various isocyanate standard substances were mixed with the XDI prepared in Synthesis Example 2 to obtain XDI compositions containing chlorinated derivatives. The amounts thereof were 500 ppm (Preparation Example 1), 1400 ppm (Preparation Example 2), and 5000 ppm (Preparation Example 3) relative to the total mass of the XDI solution.

[0159] 2. Preparation of an XDI composition containing a non-chlorinated derivative (methyl benzyl isocyanate) and / or a chlorinated derivative in the XDI composition obtained in Preparation Examples 1 to 3

[0160] (2-1) Example 1 to Example 3

[0161] 100 g of o-dichlorobenzene and 2 g of Pd / C were added to 900 g of XDI obtained in Preparation Examples 1 to 3, and the mixture was heated at 50°C and 2 kgf / cm 2 The mixture was stirred and maintained for 12 hours under a hydrogen atmosphere. After the reaction was completed, the mixture was filtered under reduced pressure, and then the solvent was removed and distilled to obtain an XDI composition containing methyl benzyl isocyanate.

[0162] (2-2) Example 4 to Example 10

[0163] The XDI obtained in Synthesis Example 1 was mixed with methylbenzyl isocyanate and a chlorinated derivative in an amount relative to the total mass of XDI to obtain an XDI composition containing both.

[0164] (2-3) Example 11

[0165] 0.2 g of Pd / C was added to 200 g of the XDI composition actually containing the chlorinated derivative obtained in Synthesis Example 1, and the mixture was heated at 50°C and 2 kgf / cm 2 The mixture was stirred and maintained for 12 hours under a hydrogen atmosphere. After the reaction was completed, the mixture was filtered under reduced pressure and then desolventized to obtain an XDI composition containing methyl benzyl isocyanate (2.7%) and a chlorinated derivative (0.06%). The obtained XDI solution was simply distilled under vacuum to obtain an XDI composition containing methyl benzyl isocyanate (0.5%) and chlorinated impurities (0.04%).

[0166] (2-4) Comparative Example 1 to Comparative Example 2

[0167] An XDI composition containing only the chlorinated derivative of the XDI obtained in Synthesis Example 2 was obtained.

[0168] The contents of methyl benzyl isocyanate and chlorinated derivatives in the XDI compositions containing methyl benzyl isocyanate in the XDI compositions obtained by reduction reaction in Examples 1 to 3, the XDI compositions containing methyl benzyl isocyanate or chlorinated derivatives in Examples 4 to 10, the XDI compositions containing methyl benzyl isocyanate and chlorinated derivatives obtained by reducing XDI containing chlorinated derivatives prepared in the actual process in Example 11, and the XDI compositions containing only chlorinated derivatives in Comparative Examples 1 and 2 are shown in Table 1.

[0169] Table 1

[0170] Example Methyl benzyl isocyanate content (ppm) Chlorinated derivatives content (ppm) 1 600 - 2 1600 - 3 5600 - 4 0.05 - 5 0.1 - 6 30000 - 7 30000 900 8 50000 1500 9 50000 1600 10 60000 - 11 5210 430 Comparative Example 1 - 1600 Comparative Example 2 - 30000

[0171] 3. Evaluation of the conversion of chlorinated derivatives to non-chlorinated derivatives by reduction reaction

[0172] like Figure 1 As shown in the figure, it was confirmed that such a conversion step can easily convert the chlorinated derivative before the reduction reaction (part (A)) into the non-chlorinated derivative after the reduction reaction (part (B)) by a simple reduction step. In addition, although XDI is difficult to separate and purify due to the small difference in boiling points between XDI and the chlorinated derivative as an impurity of XDI, it was confirmed that the separation and purification can be simplified by converting the chlorinated derivative into the non-chlorinated derivative having a large difference in boiling points according to the present invention.

[0173] 4. Preparation and evaluation of optical lenses from XDI compositions

[0174] (4-1) Preparation of optical lenses using the XDI compositions of Examples 1 to 11 and Comparative Examples 1 to 2

[0175] At room temperature, 52 g of the XDI composition prepared in Examples 1 to 11 and Comparative Examples 1 to 2, 0.015 g of dibutyltin chloride, 0.12 g of Jelico UN (internal release agent, Stepan), and 0.08 g of ultraviolet absorber were mixed and stirred for 1 hour, and then 48 g of 2,3-bis(2-mercaptoethylthio)propane-1-thiol was added to prepare a polymerizable composition. After the above polymerizable composition was stirred under reduced pressure for 1 hour to remove bubbles, it was filtered using a 1 μm polytetrafluoroethylene filter. Then, it was injected into a mold consisting of a glass mold and a tape, and the temperature was slowly raised to 120°C in an oven to polymerize for 20 hours. After removing the mold from the oven, the resin (plastic) was obtained by demolding. The obtained resin was annealed at a temperature of 120°C for 2 hours.

[0176] For each of the prepared optical lenses, the following physical properties were evaluated and organized as shown in Table 2.

[0177] Table 2

[0178]

[0179] * The yellowness index of the raw polyester lenses (3 mm flat plates) obtained by the methods of Examples 1 to 11 was measured.

[0180] **The light transmittance is measured after the raw polyester lenses obtained by the methods of Examples 1 to 11 are tinted by the above-mentioned coloration degree measurement method.

[0181] ***The impact resistance test is carried out based on the drop test (Drop Test) (16.3g*127cm).

[0182] (4-2) Evaluation of the physical properties of optical lenses prepared using the XDI compositions of Examples 1 to 11 and Comparative Examples 1 to 2

[0183] 1) The lens using the XDI composition containing methyl benzyl isocyanate at a content of 50000 ppm can be used as an ultra-high refractive index (n e 20:1.66 or above) lenses.

[0184] 2) Comparing the yellowness index of Example 6 with that of Comparative Example 1, the yellowness indexes are 1.26 and 2.30, respectively, showing a great difference. Compared with the chlorinated derivative, the lens using the XDI composition containing the reduced chlorinated derivative to methyl benzyl isocyanate shows very excellent results in terms of yellowness index. Compared with the XDI composition containing the chlorinated derivative, the XDI composition containing the reduced methyl benzyl isocyanate is more excellent in terms of yellowness index.

[0185] 3) As shown in Example 8, Example 9 and Comparative Example 2, the yellowness index tends to increase with the increase of chlorinated derivatives. When the methyl benzyl isocyanate is 50000 ppm, when the chlorinated derivative is 1500 ppm, the yellowness index is 1.38, when the chlorinated derivative is 1600 ppm, the yellowness index is 1.40, and when the chlorinated derivative is 30000 ppm, the yellowness index is 2.30, showing a tendency that the yellowness index increases with the increase of chlorinated impurities. Therefore, preferably, when methyl benzyl isocyanate and chlorinated derivatives are contained at the same time, the chlorinated derivative is less than 1500 ppm.

[0186] 4) As shown in Comparative Examples 1, 2, 3 and 10, the coloring efficiency decreases with the increase of chlorinated impurities, and the transmittance of the colored lens increases accordingly. On the contrary, the more methyl benzyl isocyanate, the higher the coloring efficiency and the lower the transmittance. Unlike chlorinated derivatives, methyl benzyl isocyanate is conducive to improving the coloring efficiency.

[0187] 5) As shown in Example 6 and Comparative Example 2, poor turbidity and texture occurred at a chlorinated derivative concentration (30,000 ppm), but good results were shown in turbidity and texture at the same concentration of methylbenzyl isocyanate, and therefore, it can be used as an optical lens material.

Claims

1. A method for preparing an isocyanate composition, wherein the isocyanate composition comprises xylylene diisocyanate, characterized in that: include: The chlorinated derivative represented by the following chemical formula (1) produced in the preparation process of the above-mentioned xylylene diisocyanate is converted into a non-chlorinated derivative represented by the following chemical formula (4) by a reduction reaction, The above reduction reaction is carried out in a hydrogen atmosphere using a metal catalyst. The isocyanate composition comprises xylylene diisocyanate, an unreduced chlorinated derivative, and a reduced non-chlorinated derivative. The content ratio of the above chlorinated derivatives is greater than 0 ppm and less than or equal to 1500 ppm. The content ratio of the above non-chlorinated derivatives ranges from 0.1ppm to 50000ppm. Among them, R1 is NCO, and R2 is H or Cl.

2. The method for preparing the isocyanate composition according to claim 1, characterized in that: According to the following reaction formula, the organic primary amine is directly reacted with a carbonylating agent in an inert solvent to obtain the above-mentioned xylylene diisocyanate:

3. The method for preparing the isocyanate composition according to claim 1, characterized in that: The above-mentioned xylylene diisocyanate is obtained by a method comprising the following steps: In the first step, an organic primary amine is reacted with hydrogen chloride gas according to the following reaction formula; and In the second step, the amine hydrochloride produced in the first step is reacted with a carbonylating agent. Step 1: Step 2:

4. The method for preparing the isocyanate composition according to claim 2, characterized in that: The carbonylating agent is selected from phosgene, diphosgene, triphosgene or a combination thereof.

5. The method for preparing the isocyanate composition according to claim 3, characterized in that: The carbonylating agent is selected from phosgene, diphosgene, triphosgene or a combination thereof.

6. The method for preparing the isocyanate composition according to claim 1, characterized in that: The method further comprises the following steps: after the reduction reaction, the obtained isocyanate composition is separated and purified by simple distillation.

7. The method for preparing the isocyanate composition according to claim 1, characterized in that: The metal catalyst is one or more of palladium, platinum and nickel.

8. An isocyanate composition comprising xylylene diisocyanate, a chlorinated derivative represented by the following chemical formula (1), and a non-chlorinated derivative represented by the following chemical formula (4), characterized in that: The chlorinated derivative represented by the chemical formula (1) is an unreduced chlorinated derivative produced in the process of preparing the above-mentioned xylylene diisocyanate, and the non-chlorinated derivative represented by the chemical formula (4) is a non-chlorinated derivative obtained by reducing the chlorinated derivative represented by the chemical formula (1) through a reduction reaction; The content ratio of the above chlorinated derivatives is greater than 0 ppm and less than or equal to 1500 ppm. The content ratio of the above non-chlorinated derivatives ranges from 0.1ppm to 50000ppm. Among them, R1 is NCO, and R2 is H or Cl.

9. The isocyanate composition according to claim 8, characterized in that The chlorinated derivative is a chlorinated derivative represented by the following chemical formula (2), and further comprises one or more of chloromethylbenzyl isocyanate, bis(chloromethyl)benzene, dichloromethylbenzyl isocyanate and chloromethyldichloromethylbenzene. Chemical formula (2) R1 is Cl or NCO, and R2 is H or Cl.

10. The isocyanate composition according to claim 8, characterized in that The content ratio of the chlorinated derivatives is in the range of greater than 0 ppm and less than or equal to 900 ppm.

11. The isocyanate composition according to claim 8, characterized in that In the above composition, the content ratio of xylylene diisocyanate is 99 mass percent or more.

12. A polymerizable composition, characterized in that: The isocyanate composition according to claim 8 and a compound containing one or more isocyanate-reactive functional groups.

13. The polymerizable composition according to claim 12, characterized in that The compound containing one or more isocyanate-reactive functional groups is a polyol compound or a polythiol compound.

14. The polymerizable composition according to claim 13, characterized in that The above-mentioned polymerizable composition is used as a coating material.

15. A resin, characterized in that: The method is obtained by a polymerization reaction of the polymerizable composition according to claim 13.

16. The resin according to claim 15, characterized in that The above resins are used as optical materials including optical lenses.

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