Xylene diisocyanate composition and method for producing isocyanurate

Abstract

The present invention relates to a xylene diisocyanate composition and a method for producing an isocyanurate using the same, which can produce an isocyanurate with high reaction efficiency by optimizing the content of chloromethylbenzyl isocyanate in the xylene diisocyanate composition, thereby optimizing reactivity so as not to cause a gelation reaction, and which has excellent film drying properties, coating heat resistance, weather resistance, and compatibility with solvents. Furthermore, the xylene diisocyanate composition recovered after the reaction has excellent storage stability and can be reused.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0187696, dated December 28, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a xylylene diisocyanate composition and a method for producing an isocyanurate using the same. [Background technology]

[0003] Polyurethane resins are generally produced by reacting polyisocyanates with active hydrogen group-containing compounds and are widely used in various industrial fields, for example, as coatings, adhesives, elastomers, etc. They are also used in electronic products, automotive interior materials, curing agents for ink coatings, etc. As polyisocyanates used in the production of polyurethane resins, for example, polyisocyanate compositions obtained by subjecting xylene diisocyanate to an isocyanuration reaction in the presence of an isocyanuration catalyst have been proposed.

[0004] Meanwhile, recently, flexible packaging has been developing significantly as a packaging method due to reasons such as packaging strength, product protection, workability during packaging, advertising effects of packaging, and reduction in packaging costs due to inexpensive mass supply of film. The adhesives used to manufacture such film or sheet laminates are generally two-component polyurethane adhesives consisting of a base agent having an active hydrogen group and a curing agent having an isocyanurate group, due to their excellent adhesive performance, cold resistance, and heat resistance, and their wide range of applicability to substrates such as various plastics and metal foils.

[0005] Known examples of such laminating adhesives include adhesive compositions containing polyester polyurethane polyol, a polyester resin mixture having carboxyl groups at the molecular terminals, orthophosphoric acid or its ester compound, and an organic isocyanate compound, and, if necessary, a silane coupling agent. It is known that such organic isocyanate compounds can include urethane-modified or isocyanurate-modified tolylene diisocyanate.

[0006] Also disclosed is a method of using a hindered phenolic antioxidant compound, such as butylated hydroxytoluene (BHT), to improve storage stability during isocyanurate production.

[0007] However, BHT and other substances are known to be harmful to the human body and the environment, and not only are there limitations on their use, but they are also known to cause problems such as discoloration during long-term storage, reduced reactivity, and increased catalyst amounts.

[0008] Therefore, there is a need for the development of a technology that can produce isocyanurates with high reaction efficiency as curing agents containing polyisocyanates, which have excellent film drying properties, good coating heat resistance, excellent weather resistance, and good compatibility with solvents. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Republic of Korea Publication Patent No. 10-2002-0092704 [Patent Document 2] Patent Publication No. 2017-222812 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention provides a xylene diisocyanate composition that contains xylene diisocyanate and chloromethyl benzyl isocyanate, and that, by containing chloromethyl benzyl isocyanate in an optimal range, has excellent storage stability and, at the same time, is capable of producing isocyanurate with high reaction efficiency.

[0011] The present invention also provides a method for producing an isocyanurate by carrying out an isocyanurate reaction using the above-mentioned xylylene diisocyanate composition, which not only has optimized reactivity to prevent gelation reaction, excellent film drying properties, good coating heat resistance, excellent weather resistance, and good compatibility with solvents, but also allows the xylylene diisocyanate composition recovered after the reaction to be reused due to its excellent storage stability. [Means for solving the problem]

[0012] According to one embodiment of the present invention, there is provided a xylylene diisocyanate composition comprising xylylene diisocyanate and chloromethyl benzyl isocyanate, wherein the chloromethyl benzyl isocyanate is contained in an amount of more than 0.1 wt % to 0.3 wt % or less, based on the total weight of the xylylene diisocyanate and chloromethyl benzyl isocyanate.

[0013] According to another embodiment of the present invention, there is provided a method for producing a xylene diisocyanate composition comprising the steps of: subjecting the xylene diisocyanate composition to an isocyanuration reaction in the presence of an isocyanuration catalyst; The xylylene diisocyanate composition comprises xylylene diisocyanate and chloromethyl benzyl isocyanate, and the amount of chloromethyl benzyl isocyanate is greater than 0.1% by weight and not more than 0.3% by weight, based on the total weight of the xylylene diisocyanate and chloromethyl benzyl isocyanate. [Effects of the Invention]

[0014] According to the present invention, by optimizing the content of chloromethyl benzyl isocyanate in the xylylene diisocyanate composition, excellent storage stability and, at the same time, the excellent effect of enabling the production of isocyanurate with high reaction efficiency can be obtained.

[0015] Furthermore, by carrying out an isocyanurate reaction using the xylylene diisocyanate composition of the present invention, the reactivity is optimized so that a gelation reaction does not occur, and an isocyanurate having excellent film drying properties, good coating heat resistance, excellent weather resistance, and good compatibility with solvents can be produced with high reaction efficiency. In addition, the xylylene diisocyanate composition recovered after the reaction has excellent storage stability and can be reused, which are excellent effects. DETAILED DESCRIPTION OF THE INVENTION

[0016] The terms used in this specification are merely used to describe exemplary embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly indicates otherwise.

[0017] Although the present invention can be embodied in various forms through various modifications, specific embodiments are described in detail below by way of example, but it should be understood that this is not intended to limit the present invention to the specific disclosed embodiments, and that the present invention encompasses all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0018] For reference, in this specification, "part by weight" refers to a relative concept in which the weight of a certain substance is used as a reference to express the weight of the remaining substance as a ratio. For example, in a mixture containing 50 g of substance A, 20 g of substance B, and 30 g of substance C, the amounts of substance B and substance C based on 100 parts by weight of substance A are 40 parts by weight and 60 parts by weight, respectively.

[0019] On the other hand, "% by weight" refers to the absolute concept of the weight of a substance expressed as a percentage of the total weight. In the example mixture, the contents of substances A, B, and C are 50%, 20%, and 30% by weight, respectively, based on a total weight of 100%. In this case, the total content of each component does not exceed 100% by weight.

[0020] The xylylene diisocyanate composition of the present invention and the method for producing an isocyanurate using the same will be described in more detail below.

[0021] Xylene diisocyanate composition According to one embodiment of the present invention, there is provided a xylylene diisocyanate composition in which the xylylene diisocyanate and chloromethyl benzyl isocyanate are present in an optimized ratio.

[0022] For example, the xylene diisocyanate composition is for producing an isocyanurate of xylene diisocyanate and is characterized by an optimized content of chloromethyl benzyl isocyanate.

[0023] A xylene diisocyanate composition according to one embodiment of the present invention contains xylene diisocyanate (XDI) and chloromethyl benzyl isocyanate (CMBI). In particular, CMBI is contained in the xylene diisocyanate composition in an optimized range, thereby improving the stability of the composition and functioning as a compound that adjusts the reaction rate.

[0024] Specifically, the content of the chloromethyl benzyl isocyanate is characterized by being in the range of more than 0.1% by weight to 0.3% by weight or less based on the total weight of the xylene diisocyanate and the chloromethyl benzyl isocyanate.

[0025] For example, the content of chloromethylbenzyl isocyanate may be in the range of more than 0.1 wt % to 0.29 wt % or less, based on the total weight of xylene diisocyanate and chloromethylbenzyl isocyanate in the xylene diisocyanate composition.

[0026] Within this range, an isocyanurate having excellent film drying properties, excellent coating heat resistance, excellent weather resistance, and good compatibility with solvents can be effectively produced with high reaction efficiency while suppressing an excessive decrease in the reaction rate of the xylene diisocyanate composition.

[0027] Preferably, the content of the chloromethyl benzyl isocyanate is about 0.11% by weight or more, or about 0.12% by weight or more, or about 0.13% by weight or more, or about 0.14% by weight or more, or about 0.15% by weight or more, and about 0.29% by weight or less, or about 0.28% by weight or less, or about 0.27% by weight or less, or about 0.25% by weight or less, or about 0.22% by weight or less, or about 0.20% by weight or less, or about 0.18% by weight or less, or about 0.15% by weight or less. For example, the content of the chloromethyl benzyl isocyanate may be about 0.11% by weight or more to 0.27% by weight.

[0028] If the content of chloromethyl benzyl isocyanate is too low, such as 0.1 wt% or less, the reactive xylene diisocyanate reacts too quickly, causing a gelation reaction, and the rapid reaction conversion of xylene diisocyanate makes it difficult to effectively produce isocyanurate. On the other hand, if the content of chloromethyl benzyl isocyanate exceeds 0.3 wt%, the reaction rate becomes too slow, and the conversion of xylene diisocyanate drops significantly even after a certain reaction time, making it difficult to effectively produce isocyanurate.

[0029] In particular, according to one embodiment of the present invention, by optimizing the content of chloromethylbenzyl isocyanate (CMBI) as described above, the reaction rate and reaction conversion rate of xylene diisocyanate can be effectively achieved even when the acid component is small in the isocyanurate production process. Optimizing the CMBI content in this way also improves the storage stability of the xylene diisocyanate composition.

[0030] Meanwhile, in the xylene diisocyanate composition according to one embodiment of the present invention, the content of the chloromethyl benzyl isocyanate can be measured by gas chromatography (GC) analysis, and the specific measurement method is as described in Test Example 1 below.

[0031] As an example, the xylene diisocyanate composition can be analyzed by gas chromatography (GC) under the following conditions, and a calibration curve can be created from the area values ​​of the gas chromatograph (GC) obtained under the following gas chromatograph (GC) analysis conditions using chloromethyl benzyl isocyanate with a purity of 95 mol% as a standard substance. 1.GC measurement conditions 1.1.Device name: Agilent 6890 1.2. Carrier gas: N2 1.3. Injector: 250℃ 1.4. Oven temperature: 80-280℃ 1.5. Column: DB-17 (30m*0.25mm*0.5μm) 1.6. Detector: FID, 280℃

[0032] In addition, the chloromethylbenzyl isocyanate may be produced during the production or synthesis of xylene diisocyanate and included in the xylene diisocyanate composition. As described below, in one embodiment, the content of chloromethylbenzyl isocyanate can be adjusted during the production or synthesis of xylene diisocyanate, for example, during the purification process.

[0033] For example, chloromethylbenzyl isocyanate (CMBI) can include ortho-chloromethylbenzyl isocyanate, meta-chloromethylbenzyl isocyanate, and para-chloromethylbenzyl isocyanate, which may be contained alone or in combination of two or more in the xylene diisocyanate composition.

[0034] Within this range, the appropriate reactivity of the xylene diisocyanate composition can be easily maintained.

[0035] In one embodiment, the content of xylylene diisocyanate in the xylylene diisocyanate composition may be 80% by weight or more, or 80% by weight or more but less than 100% by weight. Specifically, the content of xylylene diisocyanate in the xylylene diisocyanate composition may be 90% by weight or more, 95% by weight or more, 98% by weight or more, 99.5% by weight or more, 99.7% by weight or more, or 99.8% by weight or more, or may be less than 99.9% by weight.

[0036] The xylene diisocyanate (XDI) includes structural isomers such as 1,2-xylene diisocyanate (o-XDI), 1,3-xylene diisocyanate (m-XDI), and 1,4-xylene diisocyanate (p-XDI). The structural isomers of XDI may be used alone or in combination of two or more.

[0037] The xylene diisocyanate (XDI) preferably includes 1,3-XDI and 1,4-XDI, and more preferably includes 1,3-XDI.

[0038] Meanwhile, xylene diisocyanate (XDI) contained in the xylene diisocyanate composition can be produced using one of various synthesis methods known in this technical field, and the specific synthesis method can be applied without particular limitation. For example, it can be synthesized from xylene diamine.

[0039] For example, XDI can be synthesized from xylenediamine by the phosgene method. For example, xylenediamine can be directly reacted with phosgene in a solvent to produce an isocyanate, or its carbonate or hydrochloride can be produced, and then the amine salt can be reacted with phosgene (COCl2) to synthesize XDI.

[0040] As another example, XDI can be synthesized from xylylenediamine using a non-phosgene method. For example, xylylenediamine can be reacted with urea and / or an N-unsubstituted carbamic acid ester and an alcohol to produce a biscarbamate. The biscarbamate can then be thermally decomposed or degassed in the presence of a catalyst to produce XDI.

[0041] In some embodiments, a distillation step may be further carried out to remove the inert solvent and extract XDI, for example, a first distillation step to remove the inert solvent and a second distillation step to extract XDI may be carried out sequentially.

[0042] The first distillation temperature can be appropriately adjusted depending on the boiling point of the inert solvent, and the second distillation temperature may be a temperature equal to or higher than the boiling point of XDI.

[0043] The inert solvent may include an organic solvent that is substantially unreactive with the amine salt and XDI. The distillation step may be carried out using an organic solvent having a boiling point lower than that of XDI.

[0044] In one embodiment, the inert solvent may include chlorinated aromatic hydrocarbons, such as monochlorobenzene, dichlorobenzene, trichlorobenzene, chloroethylbenzene, and the like.

[0045] In an exemplary embodiment, the temperature of the distillation process can be adjusted to adjust the content of chloromethyl benzyl isocyanate in the xylene diisocyanate composition to within the above range.

[0046] In some embodiments, the second distillation temperature can be adjusted to a range of 140°C to 180°C. For example, if the second distillation temperature is less than 140°C, the xylene diisocyanate (XDI) may not be sufficiently isolated or purified. If the second distillation temperature is more than 180°C, XDI may be decomposed or a large amount of polymers may be additionally produced. Typically, the content of chloromethyl benzyl isocyanate (CMBI) can be adjusted by adjusting the reflux ratio in the purification process.

[0047] Furthermore, the xylene diisocyanate composition according to one embodiment of the present invention may further include at least one selected from the group consisting of isocyanomethylbenzaldehyde and isocyanomethylbenznitrile.

[0048] In this case, the isocyanomethylbenzaldehyde may be 0.15 wt % or less, or 0 to 0.15 wt %, or 0.001 to 0.15 wt %, based on the total weight of the entire composition, and the isocyanomethylbenznitrile may be 0.1 wt % or less, or 0 to 0.1 wt %, or 0.001 to 0.1 wt %, based on the total weight of the entire composition.

[0049] Meanwhile, according to one embodiment of the present invention, an isocyanurate containing xylene diisocyanate and chloromethylbenzyl isocyanate, in which the content of chloromethylbenzyl isocyanate (CMBI) is optimized, has excellent storage stability, and at the same time, is optimized to prevent gelation reaction in the isocyanurate production process described below, and has excellent reactivity, film drying properties, coating heat resistance, weather resistance, and solvent compatibility, and can be produced with high reaction efficiency.

[0050] Isocyanurate manufacturing method According to another embodiment of the present invention, there is provided a method for producing isocyanurate, in which an isocyanurate reaction is carried out using a xylene diisocyanate composition in which xylene diisocyanate and chloromethyl benzyl isocyanate are optimized in a predetermined ratio.

[0051] In particular, the method for producing an isocyanurate of the present invention comprises the step of subjecting the above-mentioned xylylene diisocyanate composition to an isocyanuration reaction in the presence of an isocyanuration catalyst.

[0052] Specifically, a method for producing an isocyanurate according to another embodiment of the present invention includes a step of subjecting a xylylene diisocyanate composition to an isocyanuration reaction in the presence of an isocyanuration catalyst,

[0053] The xylylene diisocyanate composition comprises xylylene diisocyanate and chloromethyl benzyl isocyanate, and the chloromethyl benzyl isocyanate is present in an amount of from greater than 0.1% to less than or equal to 0.3% by weight based on the total weight of the xylylene diisocyanate and chloromethyl benzyl isocyanate.

[0054] Here, the composition and content of xylene diisocyanate and chloromethylbenzyl isocyanate in the xylene diisocyanate composition are the same as those described above, and a detailed description thereof will be omitted.

[0055] Meanwhile, in the method for producing isocyanurate according to another embodiment of the present invention, the isocyanurate catalyst may be one or more selected from the group consisting of tertiary amine compounds, ammonium compounds, triazine compounds, and metal salts of carboxylic acids.

[0056] For example, the isocyanuration catalyst is not particularly limited as long as it is a catalyst effective for isocyanuration, and examples thereof include tertiary amines such as dimethylcyclohexylamine, tetramethylpropanediamine, tetramethylethanediamine, dimethylaminopropylamine, and 2,4,6-tris(dimethylaminomethyl)phenol; hydroxides of tetraalkylammoniums such as tetramethylammonium, tetraethylammonium, tetrabutylammonium, and trimethylbenzylammonium, and organic weak acid salts thereof; hydroxides of trialkylhydroxyalkylammoniums such as trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, and triethylhydroxyethylammonium, and organic weak acid salts thereof; alkali metal salts of alkylcarboxylic acids such as acetic acid, caproic acid, octylic acid, and myristic acid; and 2-hydroxy(trimethyl)azanium formate (2-hydroxypropyl(trimethyl)azanium triazine-based compounds such as tris-(N,N-dialkylaminoalkyl)-s-hexahydrotriazine; and metal salts of alkylcarboxylic acids such as acetic acid, caproic acid, octylic acid, and myristic acid, for example, metal salts of the alkylcarboxylic acids with tin, zinc, lead, potassium, sodium, calcium, and the like.

[0057] Specific examples include Zwitterion type hydroxyalkyl quaternary ammonium compounds, and more specific examples include N-(2-hydroxypropyl)-N,N,N-trimethylammonium-2-ethylhexanoate, N,N-dimethyl-N-hydroxyethyl-N-2-hydroxypropylammonium hexanoate, triethyl-N-2-hydroxypropylammonium hexadecanoate, trimethyl-N-2-hydroxypropylammonium phenylcarbonate, and trimethyl-N-2-hydroxypropylammonium formate.

[0058] More specifically, calcium octoate, potassium octoate, potassium acetate (Polycat 46 and Huntsman Polyurethane Catalyst LB, manufactured by Air Products), potassium 2-ethylhexanoate (Dabco K15, manufactured by Air Products), 2-hydroxypropyl(trimethyl)azanium formate (TMR-2, manufactured by Air Products), amine-based catalysts (TMR-3, TMR-7, TMR-20, manufactured by Air Products), 2,4,6-tris(dimethylaminomethyl)phenol (TMR-30), or the like, alone or in combination with two or more other metal salt catalysts, can be used in the method for producing isocyanurates of the present invention.

[0059] These isocyanurate catalysts can be used alone or in combination of two or more.

[0060] The form in which the isocyanuration catalyst is used is not particularly limited, and the solid content of the isocyanuration catalyst may be used directly, or a catalyst solution in which the isocyanuration catalyst is dissolved in an organic solvent may be used.

[0061] Preferably, the isocyanuration catalyst is used as a catalyst solution.

[0062] In the catalyst solution, examples of organic solvents include alcohols (e.g., methanol, ethanol, propanol, butanol, etc.), ketones (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), nitriles (e.g., acetonitrile, etc.), alkyl esters (e.g., methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, etc.), glycol ether esters (e.g., methyl cellosolve acetate, ethyl cellosolve acetate, methyl carbitol acetate, ethyl carbitol acetate, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, 3-methyl-3-methoxybutyl acetate, ethyl-3-ethoxypropionate), ethers (e.g., diethyl ether, tetrahydrofuran, dioxane, etc.), and polar aprotic solvents (e.g., N-methylpyrrolidone, dimethylformamide, N,N'-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphonylamide, etc.). The organic solvents can be used alone or in combination of two or more kinds.

[0063] Of the organic solvents, glycol ether esters are preferred, and propylene glycol methyl ether acetate is also preferred.

[0064] The solid content concentration of the catalyst solution (content ratio of the isocyanurate catalyst) may be, for example, 60.0% by weight or less, preferably 50.0% by weight or less.

[0065] In this method, an isocyanuration catalyst is added to a xylylene diisocyanate composition all at once or in portions, and the mixture is mixed and dispersed. Next, the xylylene diisocyanate (monomer) in the xylylene diisocyanate composition is subjected to an isocyanuration reaction.

[0066] The isocyanurate catalyst may be present in an amount of 0.001 to 0.5 parts by weight, or 0.002 to 0.4 parts by weight, or 0.005 to 0.3 parts by weight, or 0.008 to 0.2 parts by weight, or 0.01 to 0.15 parts by weight, or 0.02 to 0.12 parts by weight, or 0.05 to 0.1 parts by weight, based on 100 parts by weight of the total weight of the xylene diisocyanate composition.

[0067] For example, the addition ratio of the isocyanurate catalyst (in terms of solid content) may be, for example, 0.001 parts by weight or more, preferably 0.01 parts by weight or more, and for example, 0.5 parts by weight or less, preferably 0.3 parts by weight or less, relative to 100 parts by weight of the total weight of the xylene diisocyanate composition.

[0068] When the addition ratio of the isocyanuration catalyst is equal to or greater than the lower limit, the xylene diisocyanate composition can be reliably subjected to an isocyanuration reaction. When the addition ratio of the isocyanuration catalyst is equal to or less than the upper limit, gel formation can be stably suppressed when the isocyanuration catalyst is added to the xylene diisocyanate composition.

[0069] This isocyanuration reaction is carried out, for example, in an inert gas atmosphere such as nitrogen gas under normal pressure (atmospheric pressure). As reaction conditions for the isocyanuration reaction, the reaction temperature is, for example, room temperature (e.g., 25°C) or higher, preferably 40°C or higher, more preferably 60°C or higher, and for example, 100°C or lower, preferably 90°C or lower, and the reaction time is, for example, 30 minutes or longer, preferably 1 hour or longer, or preferably 2 hours or longer, for example, 12 hours or lower, preferably 10 hours or lower, or preferably 8 hours or shorter.

[0070] This makes it possible to obtain an isocyanurate reaction liquid containing the isocyanurate of xylene diisocyanate and unreacted xylene diisocyanate (monomer).

[0071] Furthermore, for the isocyanurate reaction and the storage stability of the product, known additives such as antioxidants and promoters (for example, organic phosphite esters) may be added as necessary.

[0072] The additive preferably includes an antioxidant.

[0073] Examples of antioxidants include phenol-based antioxidants and hindered phenol-based antioxidants. Examples include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Irganox 1010, product name, manufactured by Ciba Japan), octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Irganox 1076, product name, manufactured by Ciba Japan), 3-(4-hydroxy-3,5-diisopropylphenyl)propionic acid octyl ester (Irganox 1135, product name, manufactured by Ciba Japan), and bis[3-(3-methyl-4-hydroxy-5-tert-butylphenyl)propionic acid]ethylene bisoxybisethylene (Irganox 245, product name, manufactured by Ciba Japan). In particular, 2,6-di-tert-butyl-4-methylphenol (BHT) among hindered phenol antioxidants is known to be a substance harmful to the human body or the environment, and is therefore not only subject to limitations on its use, but also to problems such as discoloration during long-term storage, reduced reactivity, and an increased catalyst amount, making it undesirable.

[0074] These antioxidants can be used alone or in combination of two or more.

[0075] The timing of adding the additive is not particularly limited, and the additive may be added to the xylylene diisocyanate composition before the isocyanuration reaction, or to the isocyanurate reaction liquid during the isocyanuration reaction, or to the isocyanurate reaction liquid after the isocyanuration reaction. Preferably, the additive is added to the xylylene diisocyanate composition before the isocyanuration reaction.

[0076] The ratio of the additives to be added is appropriately determined depending on the purpose and application.

[0077] In the isocyanurate reaction, alcohols may be added as needed to adjust the viscosity of the product components.

[0078] To incorporate alcohols, for example, first, a xylylene diisocyanate composition and alcohols are subjected to a urethane reaction, and then the isocyanuration catalyst is added to the urethane reaction liquid to cause an isocyanuration reaction of the xylylene diisocyanate composition (including the reaction product with the alcohols), and then unreacted xylylene diisocyanate is removed as necessary.

[0079] Specifically, first, a xylene diisocyanate composition containing xylene diisocyanate and an alcohol are mixed together to cause a urethane reaction.

[0080] Examples of alcohols include monohydric alcohols (e.g., linear monohydric alcohols having 1 to 20 carbon atoms, branched monohydric alcohols having 1 to 20 carbon atoms, etc.), dihydric alcohols (e.g., linear dihydric alcohols having 2 to 20 carbon atoms, branched dihydric alcohols having 3 to 20 carbon atoms, alicyclic dihydric alcohols having 6 to 20 carbon atoms, etc.), trihydric alcohols (e.g., glycerin, trimethylolpropane, etc.), and tetrahydric or higher alcohols (e.g., tetramethylolmethane, D-sorbitol, xylitol, D-mannitol, etc.).

[0081] Furthermore, the alcohols are not particularly limited as long as they have one or more hydroxy groups in the molecule and other molecular structures do not impair the excellent effects of the present invention. For example, the alcohols may have an ester group, an ether group, a cyclohexane ring, an aromatic ring, etc. in the molecule.

[0082] Among alcohols, dihydric alcohols are preferred, and branched dihydric alcohols having 3 to 20 carbon atoms are more preferred. Examples of branched dihydric alcohols having 3 to 20 carbon atoms include 1,2-propanediol, 1,3-butylene glycol (also known as 1,3-butanediol), 1,2-butylene glycol, neopentyl glycol, and 3-methyl-1,5-pentanediol, and 1,3-butylene glycol (1,3-butanediol) is preferred.

[0083] The alcohols may be used alone or in combination of two or more kinds.

[0084] The blending ratio of the alcohols is, for example, 0.1 parts by weight or more, preferably 0.5 parts by weight or more, and also preferably 1 part by weight or more, and for example, 40 parts by weight or less, preferably 20 parts by weight or less, and also preferably 10 parts by weight or less, relative to 100 parts by weight of the xylylene diisocyanate composition.

[0085] The equivalent ratio (NCO / OH) of the isocyanate groups of the xylene diisocyanate composition to the hydroxy groups of the alcohols is, for example, 5 or more, preferably 10 or more, and more preferably 20 or more, and generally 1,000 or less.

[0086] The mixing of the xylylene diisocyanate composition and the alcohol is carried out, for example, in an inert gas atmosphere such as nitrogen gas under normal pressure (atmospheric pressure). As mixing conditions, the mixing temperature is, for example, room temperature (e.g., 25°C) or higher, preferably 40°C or higher, and for example, 100°C or lower, preferably 90°C or lower, and the mixing time is, for example, 3 minutes or longer, preferably 12 minutes or longer, and for example, 10 hours or shorter, preferably 6 hours or shorter.

[0087] Next, the isocyanuration catalyst is added to the obtained urethane reaction liquid in the above-mentioned blending ratio, and the xylene diisocyanate composition (including the reaction product with alcohols) is subjected to an isocyanuration reaction under the reaction conditions as described above.

[0088] This makes it possible to obtain an isocyanurate reaction liquid containing the isocyanurate of xylene diisocyanate and unreacted xylene diisocyanate (monomer).

[0089] Furthermore, after the conversion rate reaches a target value (e.g., 10% or more, preferably 30% or more, or 35% or more, or 40% or more, e.g., 60% or less) in the reaction step, a reaction terminator is added to terminate the isocyanurate reaction (post-reaction addition step, reaction termination step).

[0090] Examples of the reaction terminator include phosphoric acid compounds, sulfonic acid compounds, sulfonamide compounds, and aromatic compounds having a halogen group.

[0091] Examples of phosphoric acid compounds include phosphoric acid, phosphoric acid esters, etc. Examples of phosphoric acid esters include methyl phosphate, ethyl phosphate, propyl phosphate, butyl phosphate, dipropyl phosphate, butoxyethyl phosphate, 2-ethylhexyl phosphate, bis(2-ethylhexyl) phosphate, (C12-18) alkyl phosphate, isotridecyl phosphate, oleyl phosphate, tetracosyl phosphate, ethylene glycol phosphate, 2-hydroxyethyl methacrylate phosphate, and dibutyl phosphate.

[0092] Examples of sulfonic acid compounds include sulfonic acids and sulfonate esters. Examples of sulfonic acids include dodecylbenzenesulfonic acid and paratoluenesulfonic acid. Examples of sulfonate esters include alkyl dodecylbenzenesulfonates such as methyl dodecylbenzenesulfonate, ethyl dodecylbenzenesulfonate, propyl dodecylbenzenesulfonate, and butyl dodecylbenzenesulfonate; and alkyl paratoluenesulfonate esters such as methyl paratoluenesulfonate, ethyl paratoluenesulfonate, propyl paratoluenesulfonate, and butyl paratoluenesulfonate.

[0093] Examples of sulfonamide compounds include aromatic sulfonamides (e.g., benzenesulfonamide, dimethylbenzenesulfonamide, sulfanilamide, o- and p-toluenesulfonamide, hydroxynaphthalenesulfonamide, naphthalene-1-sulfonamide, naphthalene-2-sulfonamide, m-nitrobenzenesulfonamide, p-chlorobenzenesulfonamide, etc.), aliphatic sulfonamides (e.g., methanesulfonamide, N,N-dimethylmethanesulfonamide, N,N-dimethylethanesulfonamide, N,N-diethylmethanesulfonamide, N-methoxymethanesulfonamide, N-dodecylmethanesulfonamide, N-cyclohexyl-1-butanesulfonamide, 2-aminoethanesulfonamide, etc.), and the like.

[0094] Examples of aromatic compounds having a halogen group include benzoyl chloride, benzyl chloride, and chlorobenzoyl chloride.

[0095] In addition to the above, examples of reaction terminators include monochloroacetic acid.

[0096] These reaction terminators can be used alone or in combination of two or more.

[0097] The reaction terminator also acts as a storage stabilizer for the isocyanurate reaction liquid.

[0098] As the reaction terminator, preferably, an aromatic compound having a halogen group is used, more preferably, benzoyl chloride, benzyl chloride, chlorobenzoyl chloride, etc. are used.

[0099] By using these, a reaction terminator (storage stabilizer) can be added to the product component (described later) containing isocyanurate in the separation step described later, thereby improving the storage stability of the product component. Furthermore, by using the reaction terminator, it is possible to prevent the reaction terminator (storage stabilizer) from being mixed into the recovered component (described later) containing unreacted xylene diisocyanate in the separation step described later. Therefore, a recovered component with excellent reactivity can be obtained, and as described later, the recovered component can be reused in the reaction step.

[0100] The form of use of the reaction terminator is not particularly limited, and the active ingredient of the reaction terminator may be used directly, or a reaction terminator solution prepared by dissolving the reaction terminator in the organic solvent may be used. Preferably, a reaction terminator solution is used.

[0101] When the reaction terminator is used as a reaction terminator solution, preferred examples of the organic solvent include glycol ether esters, and more preferred examples include propylene glycol methyl ether acetate.

[0102] The concentration of the active ingredient in the reaction terminator (content ratio of the reaction terminator) is, for example, 10% by weight or more, preferably 20% by weight or more, for example, 70% by weight or less, preferably 60% by weight or less.

[0103] In addition, the addition ratio (in terms of active ingredient) of the reaction terminator is, for example, 100 ppm or more, preferably 200 ppm or more, more preferably 300 ppm or more, and, for example, 3000 ppm or less, preferably 1000 ppm or less, based on the total amount of the isocyanurate reaction solution.

[0104] If the addition ratio of the reaction terminator is within the above range, the reaction terminator (preservative stabilizer) can be incorporated into the product components containing isocyanurate (described below) in the separation step described later, and the storage stability of the product components can be improved. Further, when the reaction terminator is used, it is possible to suppress the mixing of the reaction terminator (preservative stabilizer) into the recovered components (described below) containing unreacted xylene diisocyanate in the separation step described later. Therefore, a recovered component with excellent reactivity can be obtained, and as described later, it is possible to reuse the recovered component in the reaction step.

[0105] On the other hand, in the present invention, the isocyanuration reaction may have a conversion rate of xylene diisocyanate measured by GPC (Gel Permeation Chromatography) analysis of about 30% by weight or more, or about 35% by weight or more, preferably about 40% by weight or more and, for example, about 60% by weight or less, or about 55% by weight or less, or about 50% by weight or less. Here, the GPC analysis method can utilize a conversion method using polystyrene standard test pieces with a molecular weight of 104 g / mol to 24600 g / mol, and the specific measurement method is as described in Test Example 2 below.

[0106] Specifically, under the following conditions, the conversion rate can be measured by a method based on GPC (Gel Permeation Chromatography) analysis. <GPC analysis conditions> Equipment used: Agilent Columns: Agilent PL Mixded D, Agilent PLgel 100Å, Agilent PLgel50 Sample concentration: 1 wt / vol% in tetrahydrofuran (THF) Carrier: THF Detection method: RI Outflow amount: 1.0ml / min Column temperature: 25℃ Detector: Agilent RI detector

[0107] Here, when creating a calibration curve, polystyrene standard test pieces with molecular weights of 104 g / mol to 24,600 g / mol can be used.

[0108] For example, the isocyanurate obtained after the isocyanuration reaction may have a content of xylene diisocyanate (XDI) trimer of 40% by weight or more, excluding XDI, as a result of GPC (Gel Permeation Chromatography) analysis, and may have a pentamer content and a heptamer content of 25% to 45% by weight, or the total of these compounds may be 75% by weight or more, or 80% by weight or more, or 85% by weight or more, or 88% by weight or more.

[0109] Here, the trimer content, pentamer content, and heptamer content in the isocyanurate obtained after the isocyanuration reaction can be measured by GPC analysis like the conversion rate measurement, and the specific measurement method is as described in Test Examples 2 and 3 below.

[0110] Specifically, the trimer content (area %) in the isocyanate composition is determined by performing gel permeation chromatography (GPC) on the isocyanate composition to obtain a molecular weight distribution curve (GPC curve) for the isocyanate composition [x-axis: logarithm (log M) of the weight average molecular weight (M), y-axis: molecular weight distribution relative to the logarithm (dwt / dlog M)], and expressing the area of ​​the fraction corresponding to the trimer as a percentage of the total area of ​​the GPC curve. For example, the trimer content (area %) can be calculated using the following formula 1: [Formula 1] Trimer content (area%) = [A / B] x 100

[0111] In the above formula 1, B is the total area under the molecular weight distribution curve (GPC curve) obtained by gel permeation chromatography analysis of the isocyanate composition, A is the area of ​​the peak corresponding to the trimer in the molecular weight distribution curve for the isocyanate composition.

[0112] The total area of ​​the GPC curve and the area of ​​the fraction corresponding to the oligomer are each determined by integration, where the oligomer refers to a polymer having a weight average molecular weight (Mw) of 600 to 1000 g / mol, and the fraction corresponding to the trimer in the GPC curve is 21.0≦logMw≦22.0.

[0113] The isocyanurate obtained after the isocyanuration reaction may have an isocyanate group (NCO) content of 10% by weight or more, or 10% by weight to 25% by weight, or 12% by weight or more, or 12% by weight to 20% by weight, or 13% by weight or more, or 13% by weight to 19% by weight. Here, the isocyanate group (NCO) content in the isocyanurate obtained after the isocyanuration reaction can be measured by a titration method using dibutylamine according to ASTM-D2572.

[0114] The isocyanurate obtained after the isocyanuration reaction may have a viscosity measured at 25° C. of 150 cps or more, or from 150 cps to 500 cps, or from 160 cps or more, or from 160 cps to 450 cps, or from 180 cps or more, or from 180 cps to 440 cps. Here, the viscosity can be measured by a method in accordance with ASTM D 2196.

[0115] Meanwhile, the method for producing an isocyanurate of the present invention may additionally include a step of separating, after completion of the isocyanurate-forming reaction, a product component containing the isocyanurate of xylene diisocyanate in the isocyanurate reaction liquid from a recovered component containing unreacted xylene diisocyanate.

[0116] In the separation step, a recovered component containing unreacted xylene diisocyanate (monomer) is separated as a low-boiling component. More specifically, the separated recovered component can contain unreacted xylene diisocyanate (monomer), an acid component, and an organic solvent blended as needed.

[0117] According to the present invention, since the xylene diisocyanate composition contains chloromethyl benzyl isocyanate at a predetermined ratio, it is possible to obtain the excellent effect of obtaining an isocyanurate with high reaction efficiency, which has excellent film drying properties, good coating heat resistance, excellent weather resistance, and good compatibility with solvents.

[0118] The present invention will be described in more detail with reference to the following examples, but the following examples are merely illustrative of the present invention and are not intended to limit the scope of the present invention. [Example]

[0119] Production Examples 1 to 5: Production of xylene diisocyanate compositions Meta-xylene diisocyanate (m-XDI, X-100, XDI product of Hanfa Solution) was measured for the content of chloromethylbenzyl isocyanate (CMBI) by GC analysis as shown in Test Example 1 below, and then chloromethylbenzyl isocyanate (CMBI) was added to each so as to obtain the CMBI content values shown in Table 1 below, and the xylene diisocyanate compositions of Production Examples 1 to 5 were produced respectively.

[0120] Comparative Production Example 1: Production of xylene diisocyanate composition Meta-xylene diisocyanate (m-XDI, X-100, XDI product of Hanfa Solution) was measured for the content of chloromethylbenzyl isocyanate (CMBI) by GC analysis as shown in Test Example 1 below, and then chloromethylbenzyl isocyanate (CMBI) was added to obtain the CMBI content values shown in Table 1 below, and the xylene diisocyanate composition of Comparative Production Example 1 was produced.

[0121] Comparative Production Examples 2-3: Production of xylene diisocyanate composition Meta-xylene diisocyanate (m-XDI, X-100, XDI product of Hanfa Solution) was measured for the content of chloromethylbenzyl isocyanate (CMBI) by GC analysis as shown in Test Example 1 below, and then a part of the content of the substance of CMBI having a lower boiling point than XDI was removed respectively so as to obtain the CMBI content values shown in Table 1 below, and the xylene diisocyanate compositions of Comparative Production Examples 2-3 were produced.

[0122] <Test Example 1> For the xylene diisocyanate compositions of Production Examples 1 to 5 and Comparative Production Examples 1 to 3, the content of chloromethylbenzyl isocyanate (CMBI) was measured by the following method, and the measured values are shown in Table 1 below.

[0123] <Method for measuring CMBI content> The xylene diisocyanate compositions of Production Examples 1 to 5 and Comparative Production Examples 1 to 3 were analyzed by gas chromatography (GC) under the following conditions. Using 95 mol% pure chloromethyl benzyl isocyanate (commercially available product, CAS no. 61924-31-0) as a standard substance, a calibration curve was created from the area values ​​of the gas chromatograph (GC) obtained under the following gas chromatograph (GC) analysis conditions.

[0124] 1.GC measurement conditions 1.1.Device name: Agilent 6890 1.2. Carrier gas: N2 1.3. Injector: 250℃ 1.4. Oven temperature: 80-280℃ 1.5. Column: DB-17 (30m*0.25mm*0.5μm) 1.6. Detector: FID, 280℃

[0125] [Table 1]

[0126] In Table 1, the content of chloromethyl benzyl isocyanate is a value (% by weight) measured based on the total weight of xylene diisocyanate and chloromethyl benzyl isocyanate.

[0127] Example 1: Preparation of isocyanurates [ka]

[0128] 800 g of the xylene diisocyanate composition of Production Example 1 was heated to 70°C, 0.72 g of a trimerization catalyst [calcium octoate: TMR-7 air product company = 1:1 weight ratio] was added, and the reaction was allowed to proceed while maintaining the reaction temperature at 70°C to 75°C. Such a reaction was carried out for about 4 hours until the conversion rate reached 40% to 60% by weight (weight basis by GPC analysis). At this time, the conversion rate was confirmed by GPC analysis as described in the following Test Example. 0.46 g of the reaction terminator chlorobenzoyl chloride was added and stirred at the same temperature for about 1 hour. Next, after cooling was allowed to proceed, the reaction solution was subjected to thin-film distillation to separate the unreacted xylene diisocyanate product. The product obtained by separation was adjusted to a solid content concentration of 75% by weight by adding ethyl acetate.

[0129] Examples 2 to 5: Production of isocyanurate The isocyanuration reaction was carried out in the same manner as in Example 1, and the isocyanurate reactions of Examples 2, 3, 4, and 5 were carried out using the xylene diisocyanate compositions of Production Examples 2, 3, 4, and 5 instead of the xylene diisocyanate composition of Production Example 1.

[0130] Comparative Examples 1 to 3: Production of isocyanurate The isocyanuration reaction was carried out in the same manner as in Example 1, and the isocyanurate reactions of Comparative Examples 1 to 3 were carried out using the xylene diisocyanate compositions of Comparative Production Examples 1 to 3 instead of the xylene diisocyanate composition of Production Example 1.

[0131] <Test Example 2> After carrying out the isocyanurate production reactions according to Examples 1 to 5 and Comparative Examples 1 to 3, the conversion rate was measured by a method using GPC (Gel Permeation Chromatography) analysis under the following conditions. <GPC analysis conditions> Equipment used: Agilent Columns: Agilent PL Mixed D, Agilent PLgel 100Å, Agilent PLgel 50 Sample concentration: 1 wt / vol% in tetrahydrofuran (THF) Carrier: THF Detection method: RI Outflow amount: 1.0ml / min Column temperature: 25℃ Detector: Agilent RI detector When preparing the calibration curve, polystyrene standard test pieces with molecular weights of 104 g / mol to 24,600 g / mol were used.

[0132] For the isocyanurate production reaction products of Examples 1 to 5 and Comparative Examples 1 to 3, the area % of unreacted XDI remaining after the reaction was measured by GPC analysis as described above, and the conversion rate was calculated as the area % of unreacted XDI remaining after the reaction compared to the XDI before the reaction.

[0133] Furthermore, during the isocyanurate production reaction in Examples 1 to 5 and Comparative Examples 1 to 3, the presence or absence of gelation was observed. If gelation occurred, it was marked with "O," and if gelation did not occur, it was marked with "X." The isocyanurate production reaction was then carried out for 5 hours, after which the conversion rate was measured. If the conversion rate was 40% or higher, it was marked with "O," and if the conversion rate was less than 40%, it was marked with "X." The XDI composition recovered from the isocyanurate production reaction product, i.e., the XDI composition containing unreacted XDI remaining after the reaction, was then stored in a dark room at 25°C for 3 months, after which the undiluted composition was observed with the naked eye to determine whether it became cloudy. If it became cloudy, it was marked with "O," and if it did not become cloudy, i.e., if transparency was maintained, it was marked with "X."

[0134] The results of the measurements as described above are shown in Table 2 below.

[0135] [Table 2]

[0136] As shown in Table 2, in Examples 1 to 5 in which the isocyanurate reaction was carried out by optimizing the content of chloromethyl benzyl isocyanate (CMBI) in the xylene diisocyanate composition according to the present invention, it was confirmed that isocyanurates having excellent film drying properties, excellent coating heat resistance, excellent weather resistance, and excellent compatibility with solvents could be produced with high reaction efficiency without a gelation reaction, compared to Comparative Examples 1 and 2.

[0137] In contrast, when the CMBI content in the xylene diisocyanate composition was excessively high at 0.6 wt%, as in Comparative Example 1, the reaction proceeded slowly, with a conversion rate of only about 20% even after a certain reaction time, and the reaction did not proceed well with the XDI. Furthermore, when the CMBI content was excessively low at 0.1 wt%, as in Comparative Example 2, the highly reactive XDI reacted suddenly, resulting in a partial gelation reaction. In Comparative Example 3, although the gelation reaction did not proceed, the rapid reaction reduced the percentage of the desired trimer structure and the NCO content, potentially making it difficult to form a uniform coating film. In particular, in the case of Comparative Example 3, the evaluation results of Test Example 3 described below indicated that the recovered XDI was unstable, resulting in cloudiness and significantly reduced storage stability.

[0138] <Test Example 3> The isocyanurate production reaction products obtained in Example 1 and Comparative Example 3 were evaluated for physical properties by the following methods, and the measurement results are shown in Table 3 below.

[0139] 1. Measurement of molecular weight content at XDI trimer level The isocyanurate production reaction products of Example 1 and Comparative Example 3 were subjected to GPC analysis in the same manner as in Test Example 2, and then the molecular weight content (area %) of XDI trimer was measured.

[0140] Specifically, the trimer content (area %) in the isocyanate composition was determined by subjecting the isocyanate composition to gel permeation chromatography (GPC) analysis to obtain a molecular weight distribution curve (GPC curve) for the isocyanate composition [x-axis: logarithm (log M) of the weight average molecular weight (M), y-axis: molecular weight distribution relative to the logarithm (dwt / dlog M)], and expressing the area of ​​the fraction corresponding to the trimer in the total area of ​​the GPC curve as a percentage. Specifically, the trimer content (area %) was calculated using the following formula 1. [Formula 1] Trimer content (area%) = [A / B] x 100

[0141] In the above formula 1, B is the total area under the molecular weight distribution curve (GPC curve) obtained by gel permeation chromatography analysis of the isocyanate composition, A is the area of ​​the peak corresponding to the trimer in the molecular weight distribution curve for the isocyanate composition.

[0142] The total area of ​​the GPC curve and the area of ​​the fraction corresponding to the oligomer are each determined by integration. Here, the oligomer refers to a polymer having a weight average molecular weight (Mw) of 600 to 1000 g / mol, and the fraction corresponding to the trimer in the GPC curve is 21.0≦logMw≦22.0.

[0143] 2. NCO content measurement The NCO content (%) of the isocyanurate production reaction products obtained in Example 1 and Comparative Example 3 was measured by a titration method using dibutylamine according to ASTM-D2572.

[0144] 3.Storage stability evaluation The storage stability of the isocyanurate production reaction products obtained in Example 1 and Comparative Example 3 was evaluated by checking whether they became cloudy after long-term storage.

[0145] Specifically, the isocyanurate production reaction products obtained in Example 1 and Comparative Example 3 were stored in a dark room at 25°C for 3 months, and then the stock composition liquids were visually observed to determine whether they were cloudy or not. If they were cloudy, the liquid was marked with "O," and if they were not cloudy, i.e., if transparency was maintained, the liquid was marked with "X."

[0146] The results of the measurements as described above are shown in Table 3 below.

[0147] [Table 3]

[0148] As shown in Table 3, in Example 1, in which the isocyanurate reaction was carried out by optimizing the content of chloromethyl benzyl isocyanate (CMBI) in the xylene diisocyanate composition according to the present invention, not only was it possible to produce an isocyanurate with excellent film drying properties, good coating heat resistance, excellent weather resistance, and good compatibility with solvents with high reaction efficiency without a gelation reaction, but the obtained ratio of trimer structure content also increased, and the NCO content was also increased, which can be effective in forming a uniform coating film.

[0149] In contrast, when the CMBI content was as low as 0.4 wt. % as in Comparative Example 3, the gelation reaction did not proceed during the production reaction, but the rapid reaction reduced the proportion of the desired trimer structure content and the NCO content, which could make it difficult to form a uniform coating film.

[0150] Therefore, it can be seen that the present invention can adjust the reactivity of xylene diisocyanate (XDI) itself by optimizing the content of chloromethylbenzyl isocyanate (CMBI) in the xylene diisocyanate composition, thereby maintaining the stability of XDI itself. Furthermore, as a result, the XDI recovered after the isocyanurate reaction has a similar level of CMBI to XDI, which has the excellent effect of maintaining the stability of XDI itself and enabling it to be reused.

Claims

1. 1. A xylylene diisocyanate composition comprising xylylene diisocyanate and chloromethyl benzyl isocyanate, wherein the chloromethyl benzyl isocyanate is present in an amount of from greater than 0.1% to less than or equal to 0.3% by weight based on the total weight of the xylylene diisocyanate and chloromethyl benzyl isocyanate.

2. The xylene diisocyanate composition according to claim 1, wherein the chloromethyl benzyl isocyanate is present in an amount of 0.11% by weight or more and 0.27% by weight or less, based on the total weight of the xylene diisocyanate and the chloromethyl benzyl isocyanate.

3. 2. The xylylene diisocyanate composition according to claim 1, wherein the xylylene diisocyanate is 99.7% by weight or more based on the total weight of the xylylene diisocyanate and chloromethyl benzyl isocyanate.

4. 2. The xylylene diisocyanate composition of claim 1, further comprising one or more members selected from the group consisting of isocyanomethylbenzaldehyde and isocyanomethylbenznitrile.

5. The method comprises the step of subjecting a xylylene diisocyanate composition to an isocyanuration reaction in the presence of an isocyanuration catalyst, the xylylene diisocyanate composition comprises xylylene diisocyanate and chloromethyl benzyl isocyanate; The method for producing isocyanurate, wherein the amount of chloromethyl benzyl isocyanate is more than 0.1% by weight and not more than 0.3% by weight based on the total weight of xylene diisocyanate and chloromethyl benzyl isocyanate.

6. 6. The method for producing an isocyanurate according to claim 5, wherein the isocyanurate catalyst is one or more selected from the group consisting of a tertiary amine compound, an ammonium compound, a triazine compound, and a metal salt of a carboxylic acid.

7. The method for producing an isocyanurate according to claim 5, wherein the isocyanurate catalyst is used in an amount of 0.001 to 0.5 parts by weight based on 100 parts by weight of the total weight of the xylene diisocyanate composition.

8. The method for producing an isocyanurate according to claim 5, wherein the conversion rate of xylene diisocyanate in the isocyanurate-forming reaction is 30% by weight or more as measured by GPC analysis.

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