Xylene diisocyanate composition and preparation method thereof

Abstract

The present invention relates to a xylene diisocyanate composition in which the content of a low-boiling point compound is controlled and a method for producing the same. Specifically, the invention relates to a xylene diisocyanate composition and a method for producing the same that can produce a high-purity xylene diisocyanate compound in high yield by controlling the purity of the amine compound and adjusting the content range of the low-boiling point compound in the reactant when producing xylene diisocyanate using phosgene.

Description

Technology Field

[0001] The present invention relates to a xylene diisocyanate composition in which the content of a low-boiling point compound is controlled, and a method for preparing the same. Background Technology

[0003] Xylylene diisocyanate (hereinafter XDI) contains an aromatic ring but is classified as an aliphatic isocyanate, and is a very useful compound as a raw material for polyurethane-based materials, polyurea-based materials, or polyisocyanurate-based materials in the chemical industry, resin industry, and paint industry.

[0004] Typically, aliphatic isocyanates are produced by the phosgenation method, in which a raw amine is reacted with phosgene. For example, XDI is produced by reacting xylylene diamine (XDA) with phosgene. However, similar to the characteristics of aliphatic isocyanates, XDI has a high reactivity of the amino group, which causes many side reactions during the phosgenation reaction. The impurities formed through these side reactions affect the reaction in which the polyurethane resin is formed, leading to a problem of deterioration in the quality of the resin.

[0005] In response to this, various methods have been researched and proposed to produce high-purity XDI by reducing the content of generated impurities.

[0006] Specifically, Korean Patent Publication No. 1994-0001948 discloses a method for producing XDI with high purity by using an ester compound, such as amyl acetate or hexyl acetate, as a reaction solvent when producing xylene diisocyanate through the reaction of xylene diamine or its hydrochloride with phosgene. However, the above method has problems such as high solvent costs and still low purity and yield.

[0007] In addition, Korean Patent Registration No. 0953019 discloses a method of applying pressure during the salting process to solve the problem of transferring amine hydrochloride salts when forming isocyanates through a phosgene reaction after producing amine hydrochloride salts through a salting process in which chain-like or cyclic aliphatic amines are reacted with hydrogen chloride.

[0008] As a non-phosgenetic method, Korean Patent Registration No. 1318828 discloses a method for producing xylene diisocyanate via a non-phosgenetic method, in which a diamine compound is reacted with alkyl chloroformate or dialkyl carbonate to produce biscarbamate, and then thermally decomposed to decompose and remove alcohols with relatively low boiling points. However, compared to the phosgenetic method, this method is not only disadvantageous in terms of cost but also difficult to apply to industrial mass production. The problem to be solved

[0010] The present invention relates to a xylene diisocyanate composition with a controlled content of a low-boiling point compound and a method for preparing the same.

[0011] The present invention aims to provide a method for producing xylene diisocyanate that can produce a high-purity xylene diisocyanate compound in high yield by controlling the purity of the amine compound and controlling the content range of a specific low-boiling point compound in the reactant when producing xylene diisocyanate using phosgene.

[0012] In addition, the present invention aims to provide a method for economically producing a high-purity xylene diisocyanate compound by increasing the process efficiency of the phosgene reaction through the use of reaction heat generated in the reaction by performing a salt reaction under specific conditions. means of solving the problem

[0014] According to one embodiment of the present invention,

[0015] xylene diisocyanate compound; and

[0016] low-boiling point compounds including isocyanomethylbenzaldehyde and isocyanomethylbenznitrile; comprising,

[0017] The above low-boiling point compound is included in an amount of 1% or less relative to the total content of the composition,

[0018] A xylene diisocyanate composition is provided.

[0020] According to one embodiment of the invention,

[0021] A first step of obtaining an amine salt compound by reacting an amine compound in a solvent with hydrogen chloride at 20°C to 90°C and under atmospheric pressure;

[0022] A second step of reacting an amine salt compound with phosgene to obtain a reaction mixture containing a xylene isocyanate compound; and

[0023] The third step comprises preparing a xylene diisocyanate composition by removing the solvent and unreacted phosgene from the above reaction mixture.

[0024] The above solvent is one or more selected from the group consisting of chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, and 1,2,4-trichlorobenzene, and

[0025] The purity of the above amine compound is 99.0% or higher, and

[0026] A method for preparing a xylene diisocyanate composition is provided, wherein the xylene diisocyanate composition comprises a low-boiling point compound in an amount of 1% or less of the total composition content, and the low-boiling point compound comprises isocyanomethylbenzaldehyde and isocyanomethylbenznitrile.

[0028] According to another embodiment of the invention,

[0029] A first step of obtaining an amine salt compound by reacting an amine compound in a solvent with hydrogen chloride at 20°C to 90°C and under atmospheric pressure;

[0030] A second step of reacting an amine salt compound with phosgene to obtain a reaction mixture containing a xylene diisocyanate compound;

[0031] A third step of preparing a xylene diisocyanate composition by removing the solvent and unreacted phosgene from the above reaction mixture; and

[0032] A fourth step of synthesizing a polyisocyanate compound by polymerizing the above xylene diisocyanate composition and a polyhydric alcohol; comprising,

[0033] The above solvent is one or more selected from the group consisting of chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, and 1,2,4-trichlorobenzene, and

[0034] The purity of the above amine compound is 99.0% or higher, and

[0035] A method for preparing a polyisocyanate composition is provided, wherein the xylene diisocyanate composition comprises a low-boiling point compound in an amount of 1% or less of the total composition content, and the low-boiling point compound comprises isocyanomethylbenzaldehyde and isocyanomethylbenznitrile.

[0037] According to another embodiment of the invention,

[0038] The aforementioned xylene diisocyanate composition; and

[0039] A polymerizable composition is provided comprising one or more of i) a polyfunctional thiol-based compound and ii) a polyfunctional episulfide-based compound.

[0041] According to another embodiment of the invention,

[0042] An optical article is provided comprising a polythiourethane polymer prepared from the above polymerizable composition. Effects of the invention

[0044] The xylene diisocyanate composition according to the present invention controls the content range of a specific low-boiling point compound, thereby enabling the production of a high-purity polyisocyanate compound in high yield without the generation of additional impurities during the synthesis of polyisocyanates.

[0045] In addition, the method for preparing a xylene diisocyanate composition according to the present invention can produce a high-purity xylene diisocyanate compound in high yield through a simple manufacturing process that controls the purity of the reaction composition and simultaneously controls the content range of a specific low-boiling point compound among the byproducts. Furthermore, the method for preparing a xylene diisocyanate composition according to the present invention can economically produce a high-purity xylene diisocyanate compound by increasing process efficiency in the subsequent phosgene reaction by controlling the salt reaction conditions of the amine compound to an appropriate range.

[0046] In addition, the method for preparing a polyisocyanate composition according to the present invention can produce a high-purity polyisocyanate compound in a high yield by controlling the purity of the reaction composition and simultaneously controlling the content range of a specific low-boiling point compound among the byproducts. Specific details for implementing the invention

[0048] The terms used herein are merely for describing exemplary embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising,” “comprising,” or “having” are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0049] The present invention is capable of various modifications and may take various forms, and specific embodiments are illustrated and described in detail below. However, this is not intended to limit the invention to the specific disclosed forms, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0051] Typically, the production of isocyanate compounds using a phosgeneization reaction is carried out by the reaction of an amine compound with phosgene, during which various impurities are generated as by-products. The inventors identified the impact of applying polyisocyanates polymerized using isocyanates containing these various impurities to actual products, and confirmed that high-purity isocyanates can be produced in high yield by controlling the purity of the reactants, such as the solvent and amine compound, and simultaneously controlling the content of the low-boiling point compound in the reaction mixture to a specific range (about 1% or less). Based on this, the inventors completed the present invention.

[0052] In particular, low-boiling point compounds among reaction byproducts can generate additional impurities during the synthesis of polyisocyanates and interfere with the activity of the catalyst, thereby affecting the reaction rate and consequently affecting the quality of the product. However, by controlling the content to an appropriate range as described above, it is possible to manufacture high-quality products without such problems. Furthermore, when applied to optical articles, these high-purity polyisocyanate compounds can significantly reduce the defect rate and improve reproducibility.

[0053] In addition, the amine compound used in the phosgene reaction is prepared in the form of a chloride through a salt reaction. In the present invention, the salt reaction is carried out under relatively mild conditions in a specific solvent, so the phosgene reaction can be easily performed without undergoing additional cooling or heating processes, which is highly economical.

[0055] Xylene Diisocyanate Composition

[0056] According to one embodiment of the invention, a xylene diisocyanate composition is provided comprising: a xylene diisocyanate compound; and a low-boiling point compound comprising isocyanomethylbenzaldehyde and isocyanomethylbenznitrile, wherein the low-boiling point compound is included in an amount of 1% or less relative to the total content of the composition. Here, the content range of the low-boiling point compound is a GC area (%) measured by gas chromatography (GC) analysis, and the specific measurement method thereof will be explained in more detail in the experimental examples described later.

[0057] Meanwhile, if the low-boiling point compound is included in the composition in an amount exceeding 1%, additional impurities may be generated during the synthesis of polyisocyanate, and the reaction rate may be affected by hindering the activity of the catalyst. Consequently, the quality of the product is affected. However, by using a xylene diisocyanate composition controlled to an appropriate content range as described above, high-purity polyisocyanate can be manufactured without such problems. Furthermore, when applied to optical articles, this polyisocyanate compound can significantly reduce the defect rate and improve reproducibility.

[0058] The content of the low-boiling point compound may preferably be 0.7% or less, 0.5% or less, or 0.3% or less with respect to the total content of the xylene diisocyanate composition. The lower limit of the low-boiling point compound is 0% or more, and preferably may be included in an amount of 0.0001% or more, 0.0001% to 0.7%, or 0.001% to 0.5%, and is suitable for realizing the aforementioned effect within the above content range.

[0059] The above isocyanomethylbenzaldehyde (IMBAl) may be included in an amount of 0.0001 to 0.15% with respect to the total content of the composition, preferably 0.001 to 0.15%, or 0.0003 to 0.11%.

[0060] In addition, the isocyanomethylbenznitrile (IMBN) may be included in an amount of 0.0001 to 0.1% relative to the total content of the composition, preferably 0.0003 to 0.1%, or 0.0008 to 0.06%.

[0061] According to one embodiment of the invention, the low boiling point compound may further include chloromethylbenzyl isocyanate (CMBI). In this case, the chloromethylbenzyl isocyanate may be included in an amount of 0.01 to 0.2% with respect to the total content of the composition, and preferably in an amount of 0.05 to 0.15%.

[0063] The above xylene diisocyanate composition may further include additional additives to maintain storage stability in addition to the above components.

[0064] The types of the above additional additives are not particularly limited and may further include antioxidants, heat stabilizers, polymerization inhibitors, etc., commonly used in the field. The content of the above additives is not particularly limited and may be used within an appropriate range that does not impede the purpose of the present invention.

[0066] The above xylene diisocyanate composition can be used in a wide range of fields due to its excellent physical properties, and among them, it can be used as an optical article.

[0067] The above xylene diisocyanate composition can be prepared according to the manufacturing method described below.

[0069] Method for preparing a xylene diisocyanate composition

[0070] Specifically, a method for preparing a xylene diisocyanate composition according to one embodiment of the invention comprises: a step of obtaining an amine salt compound by reacting an amine compound with hydrogen chloride in a solvent at 20°C to 90°C and under atmospheric pressure; a step of obtaining a reaction mixture containing a xylene isocyanate compound by reacting the amine salt compound with phosgene; and a third step of preparing a xylene diisocyanate composition by removing the solvent and unreacted phosgene from the reaction mixture.

[0072] (Epidemic reaction)

[0073] First, a first step (salt reaction) is performed to obtain an amine salt compound by reacting an amine compound in a solvent with hydrogen chloride at 20°C to 90°C and under atmospheric pressure.

[0074] Since the salt reaction to obtain the above amine salt compound is carried out in a specific solvent at 20°C to 90°C and under atmospheric pressure, the phosgene reaction can be easily carried out without undergoing additional cooling or heating processes in the subsequent phosgene reaction, which is highly economical.

[0075] Here, atmospheric pressure refers to pressure without the application of pressure-reducing equipment such as a separate vacuum pump. For example, this corresponds to approximately 760 mmHg, which is typical atmospheric condition. It is desirable to perform the reaction within this range to maintain a homogeneous phase of the amine salt compound. If the salt reaction is performed under pressure exceeding atmospheric pressure conditions, the particle size of the amine salt compound may become non-uniform.

[0076] Meanwhile, if the above salt reaction is performed at a temperature below 20°C, the particle size of the amine salt compound may become non-uniform, which may inhibit the subsequent phosgene reaction. In addition, if performed at a temperature above 90°C, there is a problem that it is difficult to control the salt reaction itself. Preferably, the salt reaction can be performed at a temperature between 30°C and 80°C. Meanwhile, the temperature of the salt reaction can be controlled by the heat of reaction resulting from the introduction of hydrogen chloride without special temperature control.

[0077] The above solvent is one or more selected from the group consisting of chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, and 1,2,4-trichlorobenzene, and these are inert organic solvents that can contribute to reducing the content of by-products. In addition, these solvents have high polarity, which helps dissolve the amine salt compound and facilitates the reaction. Most preferably, 1,2-dichlorobenzene may be used. On the other hand, if a solvent such as n-amyl acetate is used, the particle size of the amine salt compound may become non-uniform, which may inhibit the phosgene reaction.

[0078] Preferably, the purity of the solvent can satisfy 99.0% or higher, thereby minimizing side reactions in the phosgenation reaction and, in particular, controlling the content of low-boiling point compounds among the side products to the aforementioned range, so that high-purity xylene diisocyanate can be produced. More preferably, the purity of the solvent is 99.0% to 99.99%. It is desirable to achieve the aforementioned effects within the above content range.

[0080] By satisfying a purity of 99.0% or higher for the above amine compound, side reactions in the phosgenation reaction can be minimized, and in particular, a high-purity xylene diisocyanate compound can be produced by controlling the content of low-boiling point compounds among the side products to the aforementioned range. More preferably, the purity of the above amine compound is 99.0% to 99.99%. It is desirable to achieve the aforementioned effects within the above content range.

[0081] The above amine compound may be one or more selected from the group consisting of m-xylene diamine, p-xylene diamine, o-xylene diamine, and their chlorides (e.g., hydrochloride or carbonate, etc.). Preferably, the chloride of the above amine compound may be used, and in this case, it is desirable to increase the conversion rate to the product during the preparation of the xylene isocyanate compound described later, thereby lowering the content of impurities.

[0082] More specifically, the amine compound can be obtained through the following reaction and exhibit a purity within the aforementioned range:

[0083] 1) m-Xylene ammoxidation reaction

[0084]

[0085] 2) IPN hydrogenation reaction

[0086]

[0087] XDA is synthesized by ammoxidation of m-xylene in the first step to produce IPN (isophalonitrile) followed by a hydrogenation reaction in the second step. Impurities that may be generated during the second step of synthesis are labeled #1 to #3. Although various other impurities may be generated, the content of the impurities is trace (about 1% or less).

[0088] Meanwhile, the above impurities may affect the content of the low-boiling point compound in the process of obtaining a reaction mixture containing the xylene isocyanate compound described later, that is, the higher the purity of the amine compound, the lower the content of the low-boiling point compound can be reduced.

[0089] The above amine compound may be included in an amount of 1 to 20 weight% relative to the total solvent content. If the content of the amine compound exceeds 20 weight%, the stirring process during the reaction becomes difficult, there is a risk that a large amount of amine compound may precipitate, and the non-uniform reaction may affect the increase in the content of the low-boiling point compound. Preferably, it may be included in an amount of 1 to 15 weight% or 5 to 15 weight%.

[0091] (Phosgene reaction)

[0092] Next, the process includes a second step of reacting the above amine salt compound with phosgene to obtain a reaction mixture containing a xylene diisocyanate compound.

[0093] By carrying out the salt reaction under the aforementioned conditions, a homogeneous chloride is obtained, making it easier to carry out the phosgene reaction.

[0094] The temperature of the above reaction is not particularly limited, but can be carried out at 110°C to 160°C, and more preferably at 120°C to 140°C. If the reaction temperature exceeds 160°C, the concentration of by-products increases, and problems may arise such as thermal decomposition of reactants and products.

[0095] Preferably, the process can be carried out by gradually increasing the temperature inside the reactor to the aforementioned range and then adding phosgene, and more preferably, by adjusting the temperature inside the reactor to 110°C to 140°C after adding phosgene. The reactor temperature can preferably be adjusted to 120°C to 135°C.

[0096] In addition, according to one embodiment of the invention, in the reaction between the amine salt compound and phosgene, the method of introducing phosgene is not particularly limited. For example, the reaction may be carried out by introducing the amine salt compound and phosgene into a single reactor and stirring, or by injecting phosgene into a reactor containing the amine salt compound through a mixing eductor, which is a mixing nozzle. Preferably, the reaction may be carried out by injecting phosgene through a mixing eductor in order to uniformly mix the reactants and improve reaction efficiency, which is desirable as it allows for a shorter reaction time and a reduction in impurity content.

[0097] The time of the above reaction is not particularly limited, but it may be carried out for about 1 to 4 hours after the addition of phosgene is completed. Preferably, it may be carried out for 1 to 3 hours.

[0098] In addition, preferably, after the above reaction is completed, a process of reducing the temperature inside the reactor to 70°C to 80°C may be further performed.

[0100] (Refining process)

[0101] Next, the process includes a third step of preparing a xylene diisocyanate composition by removing the solvent and unreacted phosgene from the reaction mixture.

[0102] After the reaction with phosgene is completed, solvent, unreacted phosgene, etc. exist in the reaction mixture, and these are removed to produce a xylene diisocyanate composition containing a xylene diisocyanate compound.

[0103] Meanwhile, according to one embodiment of the invention, the third step may further include a purification process after removing the solvent and unreacted phosgene from the reaction mixture.

[0104] The method for performing the removal and purification process of the above solvent and phosgene is not particularly limited, and methods commonly practiced in the field may be applied. For example, unreacted phosgene and hydrogen chloride gas remaining in the reaction mixture can be removed through a nitrogen bubbling process, and the solvent can be removed through a distillation process.

[0105] The above purification process can be carried out by purifying through fractional distillation and thin-film distillation under reduced pressure, and in the case of fractional distillation, the plant process can proceed with a tray distillation column or a packing distillation column. The theoretical number of stages of the distillation column is 2 stages or more, preferably 5 stages or more. Preferably 50 stages or less, 40 stages or less.

[0106] The xylene diisocyanate composition prepared according to the aforementioned salt reaction, phosgene reaction, and purification process comprises a low-boiling point compound in an amount of 1% or less relative to the total composition content. Here, the low-boiling point compound comprises isocyanomethylbenzaldehyde and isocyanomethylbenznitrile. The content range of the low-boiling point compound is the GC area (%) measured by gas chromatography (GC) analysis, and the specific measurement method thereof will be explained in more detail in the experimental examples described later.

[0107] If the above-mentioned low-boiling point compound is included in an amount exceeding 1%, additional impurities may be generated during subsequent polyisocyanate synthesis, and the reaction rate may be affected by interfering with the activity of the catalyst. Consequently, this affects the quality of the product. However, by using a xylene diisocyanate composition controlled to an appropriate content range as described above, high-purity polyisocyanate can be manufactured without such problems. Furthermore, when applied to optical articles, this polyisocyanate compound can significantly reduce the defect rate and improve reproducibility.

[0108] The content of the low-boiling point compound may preferably be 0.7% or less, 0.5% or less, or 0.3% or less with respect to the total content of the xylene diisocyanate composition. The lower limit of the low-boiling point compound is 0% or more, and preferably may be included in an amount of 0.0001% or more, 0.0001% to 0.7%, or 0.001% to 0.5%, and is suitable for realizing the aforementioned effect within the above content range.

[0109] The above isocyanomethylbenzaldehyde (IMBAl) may be included in an amount of 0.0001 to 0.15% with respect to the total content of the composition, preferably 0.001 to 0.15%, or 0.0003 to 0.11%.

[0110] In addition, the isocyanomethylbenznitrile (IMBN) may be included in an amount of 0.0001 to 0.1% relative to the total content of the composition, preferably 0.0003 to 0.1%, or 0.0008 to 0.06%.

[0111] According to one embodiment of the invention, the low boiling point compound may further include chloromethylbenzyl isocyanate (CMBI). In this case, the chloromethylbenzyl isocyanate may be included in an amount of 0.01 to 0.2% with respect to the total content of the composition, and preferably in an amount of 0.05 to 0.15%.

[0113] Polymerizable composition

[0114] According to one embodiment of the invention, the above xylene diisocyanate composition; and

[0115] A polymerizable composition is provided comprising one or more of i) a polyfunctional thiol-based compound and ii) a polyfunctional episulfide-based compound.

[0116] The above polymerizable composition may include the isocyanate composition, the polyfunctional thiol-based compound, and the polyfunctional episulfide-based compound in a mixed state or in a separated state. That is, within the above polymerizable composition, the isocyanate composition and the polyfunctional thiol-based compound or the polyfunctional episulfide-based compound may be in a state where they are in contact with each other or in a state where they are separated so as not to come into contact with each other.

[0117] The above-mentioned polyfunctional thiol-based compound may be a compound containing two or more thiol (Thio, -SH) groups within the molecule and may have an aliphatic, alicyclic, or aromatic backbone.

[0118] The above-mentioned polyfunctional episulfide-based compound may be a compound containing two or more episulfides, i.e., thioepoxy groups, within the molecule, and may have an aliphatic, alicyclic, or aromatic backbone.

[0119] According to one example, the polyfunctional thiol-based compound comprises 4,8-bis(mercaptomethyl)-3,6,9-trithioundecane-1,11-dithiol, 4,7-bis(mercaptomethyl)-3,6,9-trithioundecane-1,11-dithiol, 5,7-bis(mercaptomethyl)-3,6,9-trithioundecane-1,11-dithiol, bis(2-mercaptoethyl)sulfide, 4-mercaptomethyl-3,6-dithioctan-1,8-dithiol, 2,3-bis(2-mercaptoethylthio)propane-1-thiol, 2,2-bis(mercaptomethyl)propane-1,3-dithiol, 2-(2-mercaptoethylthio)propane-1,3-dithiol, 2-(2,3-bis(2-mercaptoethylthio)propylthio)ethanethiol, bis(2,3-dimercaptopropanyl)sulfide, bis(2,3-dimercaptopropanyl)disulfide, 1,2-bis(2-(2-mercaptoethylthio)-3-mercaptopropylthio)ethane, bis(2-(2-mercaptoethylthio)-3-mercaptopropyl)disulfide, 2-(2-mercaptoethylthio)-2-mercapto-3-[3-mercapto-2-(2-mercaptoethylthio)-propylthio]propylthio-propane-1-thiol, 2-(2-mercaptoethylthio)-3-mercapto-3-[3-mercapto-2-(2-mercaptoethylthio)-propylthio]propylthio-propane-1-thiol, 2-(2-mercaptoethylthio)-3-(2-(2-[3-mercapto-2-(2-mercaptoethylthio)-propylthio]ethylthio)ethylthio)-propane-1-thiol, (4R,11S)-4,11-bis(mercaptomethyl)-3,6,9,12-tetrathiatetradecane-1,14-dithiol, (S)-3-((R-2,3-dimercaptopropyl)thio)propane-1,2-dithiol, 4,14-bis(mercaptomethyl)-3,6,9,12,15-pentathiaheptadecane-1,17-dithiol, (S)-3-((R-3-mercapto-2-((2-mercaptoethyl)thio)propyl)thio)propyl)thio)-2-((2-mercaptoethyl)thio)propane-1-thiol, 3,3'-dithiobis(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-hexathioctadecane-1,18-dithiol,2-(2-mercaptoethylthio)-3-[4-(1-{4-[3-mercapto-2-(2-mercaptoethylthio)-propoxy]-phenyl}-1-methylethyl)-phenoxy]-propane-1-thiol, 2,2-bis-(3-mercapto-propionyloxymethyl)-butyl ester, pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(2-mercaptoacetate), bis-pentaerythritol-ether-hexakis(3-mercaptopropionate), trimethylolpropane tris(2-mercaptopropionate), trimethylolpropane tris(3-mercaptopropionate), glycerol trimercaptopropionate, 1,1,3,3-tetrakis(mercaptomethylthio)propane, It may include one or more selected from 1,1,2,2-tetrakis(mercaptomethylthio)ethane, 4,6-bis(mercaptomethylthio)-1,3-dithian, 2-(2,2-bis(mercaptomethylthio)ethyl)-1,3-dithian, and 2,5-bismercaptomethyl-1,4-dithian.

[0121] According to one example, the polyfunctional episulfide-based compound is bis(β-epithiopropylthio)methane, 1,2-bis(β-epithiopropylthio)ethane, 1,3-bis(β-epithiopropylthio)propane, 1,2-bis(β-epithiopropylthio)propane, 1-(β-epithiopropylthio)-2-(β-epithiopropylthiomethyl)propane, 1,4-bis(β-epithiopropylthio)butane, 1,3-bis(β-epithiopropylthio)butane, 1-(β-epithiopropylthio)-3-(β-epithiopropylthiomethyl)butane, 1,5-bis(β-epithiopropylthio)pentane, 1-(β-epithiopropylthio)-4-(β-epithiopropylthiomethyl)pentane, 1,6-bis(β-epithiopropylthio)hexane, 1-(β-epithiopropylthio)-5-(β-epithiopropylthiomethyl)hexane, 1-(β-epithiopropylthio)-2-[(2-β-epithiopropylthioethyl)thio]ethane, 1-(β-epithiopropylthio)-2-[[2-(2-β-epithiopropylthioethyl)thioethyl]thio]ethane, tetrakis(β-epithiopropylthiomethyl)methane, 1,1,1-tris(β-epithiopropylthiomethyl)propane, 1,5-bis(β-epithiopropylthio)-2-(β-epithiopropylthiomethyl)-3-thipentane, 1,5-bis(β-epithiopropylthio)-2,4-bis(β-epithiopropylthiomethyl)-3-thipentane, 1-(β-epithiopropylthio)-2,2-bis(β-epithiopropylthiomethyl)-4-thihexane, 1,5,6-tris(β-epithiopropylthio)-4-(β-epithiopropylthiomethyl)-3-thihexane, 1,8-bis(β-epithiopropylthio)-4-(β-epithiopropylthiomethyl)-3,6-dithioctane, 1,8-bis(β-epithiopropylthio)-4,5-bis(β-epithiopropylthiomethyl)-3,6-dithioctane, 1,8-bis(β-epithiopropylthio)-4,4-bis(β-epithiopropylthiomethyl)-3,6-dithioctane, 1,8-bis(β-epithiopropylthio)-2,4,5-tris(β-epithiopropylthiomethyl)-3,6-dithioctane, 1,8-bis(β-epithiopropylthio)-2,5-bis(β-epithiopropylthiomethyl)-3,6-dithioctane, 1,9-bis(β-epithiopropylthio)-5-(β-epithiopropylthiomethyl)-5-[(2-β-epithiopropylthioethyl)thiomethyl]-3,7-dithianonan, 1,10-bis(β-epithiopropylthio)-5,6-bis[(2-β-epithiopropylthioethyl)thio]-3,6,9-trithiadecane, 1,11-bis(β-epithiopropylthio)-4,8-bis(β-epithiopropylthiomethyl)-3,6,9-trithioundecane, 1,11-bis(β-epithiopropylthio)-5,7-bis(β-epithiopropylthiomethyl)-3,6,9-trithioundecane, 1,11-Bis(β-epithiopropylthio)-5,7-[(2-β-epithiopropylthioethyl)thiomethyl]-3,6,9-trithioundecane, 1,11-Bis(β-epithiopropylthio)-4,7-Bis(β-epithiopropylthiomethyl)-3,6,9-trithioundecane, 1,3-Bis(β-epithiopropylthio)cyclohexane, 1,4-Bis(β-epithiopropylthio)cyclohexane, 1,3-Bis(β-epithiopropylthiomethyl)cyclohexane, 1,4-Bis(β-epithiopropylthiomethyl)cyclohexane, Bis[4-(β-epithiopropylthio)cyclohexyl]methane, 2,2-Bis[4-(β-epithiopropylthio)cyclohexyl]propane, Bis[4-(β-epithiopropylthio)cyclohexyl]sulfide, 2,5-bis(β-epithiopropylthiomethyl)-1,4-dithian, 2,5-bis(β-epithiopropylthioethylthiomethyl)-1,4-dithian, 1,3-bis(β-epithiopropylthio)benzene, 1,4-bis(β-epithiopropylthio)benzene, 1,3-bis(β-epithiopropylthiomethyl)benzene, 1,4-bis(β-epithiopropylthiomethyl)benzene, bis[4-(β-epithiopropylthio)phenyl]methane, 2,2-bis[4-(β-epithiopropylthio)phenyl]propane, bis[4-(β-epithiopropylthio)phenyl]sulfide, It may include one or more selected from bis[4-(β-epithiopropylthio)phenyl]sulfone and 4,4'-bis(β-epithiopropylthio)biphenyl.

[0123] In the above polymerizable composition, the molar ratio of (theo group + episulfide group) to the isocyanate group may be about 0.5 to about 1.5, or about 0.8 to about 1.2, or about 0.9 to about 1.1, but the present invention is not necessarily limited thereto.

[0125] In addition, the above polymerizable composition may further include an appropriate amount of additives such as release agents, heat stabilizers, UV stabilizers, pigments, urethane reaction catalysts, etc.

[0126] The above-mentioned release agent is a type of surfactant component, such as a fluorine-based nonionic surfactant containing a perfluoroalkyl group; a silicone-based nonionic surfactant containing a dimethylpolysiloxane group; and quaternary ammonium salts such as trimethylcetylammonium salt, trimethylstearyl, dimethylethylcetylammonium salt, triethyldodecylammonium salt, trioctylmethylammonium salt, diethylcyclohexadodecylammonium salt, etc.

[0127] The above heat stabilizers may be, for example, metal fatty acid salt-based, phosphorus-based, lead-based, organotin-based compounds, etc. These may be used alone or in combination of two or more.

[0128] The above-mentioned UV stabilizer may be, for example, benzophenone-based, benzotriazole-based, salicylate-based, cyanoacrylate-based, oxanilide-based compounds, etc.

[0129] Examples of the above pigments include fluorescent whitening agents, fluorescent pigments, inorganic pigments, etc.

[0130] The above urethane reaction catalyst may be used alone or in combination of two or more types, for example, dialkyltin halide compounds such as dibutyltin dichloride and dimethyltin dichloride; dialkyltin dicarboxylate compounds such as dimethyltin diacetate, dibutyltin dioctanoate and dibutyltin dilaurate; dialkyltin diallkoxide compounds such as dibutyltin dibutoxide and dioctyltin dibutoxide; dialkyltin dithioalkoxide compounds such as dibutyltin di(thiobutoxide); dialkyltin oxide compounds such as di(2-ethylhexyl)tin oxide, dioctyltin oxide, and bis(butoxydibutyltin) oxide; dialkyltin sulfide compounds, etc.

[0132] Optical items

[0133] In addition, according to one embodiment of the invention, an optical article is provided comprising a polythiourethane polymer prepared from the polymerizable composition.

[0134] More preferably, the optical article may be an optical lens, for example, an eyeglass lens, a camera lens, a plastic lens, a prism, etc.

[0136] Method for preparing a polyisocyanate composition

[0137] According to another embodiment of the invention, a method for preparing a polyisocyanate composition is provided by applying the method for preparing the xylene diisocyanate composition.

[0138] Specifically, a method for manufacturing a polyisocyanate composition according to one embodiment of the invention is,

[0139] A first step of obtaining an amine salt compound by reacting an amine compound in a solvent with hydrogen chloride at 20°C to 90°C and under atmospheric pressure;

[0140] A third step of preparing a xylene diisocyanate composition by removing the solvent and unreacted phosgene from the above reaction mixture; and

[0141] A fourth step of synthesizing a polyisocyanate compound by polymerizing the above xylene diisocyanate composition and a polyhydric alcohol; is included.

[0142] The contents of the above first, second, and third steps can all be applied in the same way as the method for preparing the xylene diisocyanate composition described above.

[0143] Accordingly, the solvent is one or more selected from the group consisting of chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, and 1,2,4-trichlorobenzene, the purity of the amine compound is 99.0% or higher, and the xylene diisocyanate composition contains a low-boiling point compound in an amount of 1% or less relative to the total content of the composition. Here, the low-boiling point compound includes isocyanomethylbenzaldehyde and isocyanomethylbenznitrile.

[0145] Next, the fourth step comprises synthesizing a polyisocyanate compound by mixing the xylene diisocyanate composition with a polyhydric alcohol and polymerizing it.

[0146] The isocyanate compound included in the above composition is of high purity, and since the low-boiling point compound in the composition satisfies 1% or less, the generation of by-products during the polymerization step is significantly reduced.

[0147] Preferably, the polyhydric alcohol is a compound containing two or more hydroxyl groups in one molecule, specifically, it may be a compound having two or more or three or more, and eight or fewer or four or fewer hydroxyl groups in the molecule.

[0148] Specific examples include dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 2-methyl-2,3-butanediol, 1,6-hexanediol, 1,2-hexanediol; trihydric alcohols such as glycerol, trimethylolethane, and trimethylolpropane (TMP); tetrahydric alcohols such as diglycerin, ditrimethylolpropane, pentaerythritol, and dipentaerythritol; pentahydric alcohols such as L-arabinitol, ribitol, and xylitol; hexahydric alcohols such as D-glucitol, D-mannitol, and galactitol; and heptahydric alcohols such as trehalose. Examples include octahydric alcohols such as sucrose and maltose, or low molecular weight polyols, among which diethylene glycol, glycerol, trimethylol ethane, trimethylolpropane, or a mixture thereof may be used. More specifically, it may be preferable to use a trihydric alcohol such as glycerol, trimethylolpropane, or trimethylol ethane alone, or to use a mixture of the trihydric alcohol and other polyhydric alcohols.

[0150] Meanwhile, the above polymerization reaction consists of a urethane reaction (or addition polymerization reaction) between the isocyanate compound and the hydroxyl groups in the polyhydric alcohol.

[0151] Accordingly, it may be desirable to appropriately determine the amount of the polyhydric alcohol used by considering the urethane reaction with the isocyanate compound, the physical properties to be realized in the manufactured polyisocyanate such as viscosity, and the application of the polymer. Specifically, the polyhydric alcohol may be added in an amount such that the molar ratio of hydroxyl groups in the polyhydric alcohol to 1 mole of isocyanate groups of the isocyanate compound is 0.05 or more, or 0.15 or more, and 1 or less, or 0.8 or less. If the molar ratio of hydroxyl groups to isocyanate groups falls outside the above range and is less than 0.05, the viscosity of the manufactured polymer decreases due to the excess isocyanate groups, and as a result, there is a risk that processability will decrease. In addition, if the molar ratio of hydroxyl groups to isocyanate groups exceeds 1, there is a risk that the anti-discoloration effect will decrease due to the excess hydroxyl groups.

[0152] The above polymerization reaction can be carried out under atmospheric pressure conditions and an inert gas atmosphere such as nitrogen or argon.

[0153] It is desirable that the above polymerization reaction be carried out in a temperature range of 40°C or higher, or 60°C or higher, and 100°C or lower, or 80°C or lower, so that the reaction rate can be easily controlled without concern for discoloration and the reaction efficiency can also be increased.

[0154] The above polymerization reaction may be carried out under conditions without a catalyst, or in the presence of a catalyst that typically promotes urethane reactions, such as tin-based or amine-based catalysts. When carried out in the presence of a catalyst, additional catalyst may be added when adding polyhydric alcohol to the monomer composition.

[0155] The above polymerization reaction can be predicted by measuring the concentration of isocyanate groups in the polymerization reaction product using the n-dibutylamine method with a transitional titration device or by measuring the refractive index, and in the present invention, the polymerization reaction is carried out until the concentration of isocyanate groups in the polymerization reaction product reaches the calculated value of the isocyanate groups remaining after reacting with the polyhydric alcohol.

[0156] As a result of the polymerization reaction described above, polyisocyanate is produced.

[0158] The polyisocyanate prepared as described above can be produced into polyurethane through a reaction with a polyol, and precise control of the physical properties of polyurethane products is possible by using the polyisocyanate according to the present invention.

[0160] The above polyisocyanate specifically includes a urethane bond formed by the reaction of some or all of the isocyanate groups of the isocyanate compound in the reaction mixture obtained from the aforementioned phosgenation reaction with the hydroxyl groups of a polyhydric alcohol.

[0161] The present invention includes a high-purity xylene diisocyanate compound in the reaction mixture, and in particular, can produce a high-purity polyisocyanate with a high yield with a content of 1 weight% or less of a low-boiling point compound, and can produce a product without discoloration or turbidity. More preferably, the content may be 0.7% or less, 0.5% or less, or 0.3% or less with respect to the total content of the composition. The lower limit of the low-boiling point compound is 0% or more, and preferably, it may be included in an amount of 0.0001% or more, 0.0001% to 0.7%, or 0.001% to 0.5%. The content range of the low-boiling point compound is the GC area (%) measured by gas chromatography (GC) analysis, and the specific measurement method thereof will be explained in more detail in the experimental examples described later.

[0163] In addition to the polyisocyanate, the product obtained as a result of the above polymerization reaction may contain stabilizers and unreacted diisocyanates that did not participate in the polymerization reaction.

[0164] Accordingly, a method for preparing a polyisocyanate composition according to one embodiment of the invention may optionally further include a step of purifying the product obtained as a result after the completion of the polymerization reaction to remove unreacted diisocyanate.

[0165] The above purification process can be carried out by conventional purification methods such as distillation and solvent extraction, and in the present invention, it can be carried out by a distillation purification method such as thin-film distillation in terms of excellent efficiency in removing unreacted polyisocyanate.

[0166] The pressure and temperature during the above distillation purification process can be appropriately controlled according to the composition of the polyisocyanate composition, the distillation apparatus, etc. In the present invention, the above distillation purification process can be performed under a pressure of 0.001 kPa or higher and 1 kPa or lower, or 0.5 kPa or lower.

[0167] In addition, the distillation purification process can be performed at a temperature of 70°C or higher, or 90°C or higher, or 200°C or lower, or 180°C or lower. If the temperature is below 70°C, there is a risk that the distillation purification efficiency will decrease, and if it exceeds 200°C, there is a risk that the polyisocyanate will be denatured due to the high temperature.

[0168] The above distillation purification process can lower the content of unreacted diisocyanate in the polyisocyanate composition, and it is desirable that the lower the content, the greater the stability of the composition.

[0170] Polyisocyanate composition

[0171] According to another embodiment of the present invention, a composition prepared according to the method for preparing the polyisocyanate composition is provided.

[0172] The above polyisocyanate composition may further include a diluent solvent, and accordingly exhibits appropriate coating properties, making it easy to apply to a product.

[0173] Preferably, ethyl acetate may be used as a diluting solvent, and, for example, the isocyanate group content (NCO%) in the composition may be included such that the solid content is 75% by weight. By having an isocyanate group content within the above range, an appropriate crosslinking density is exhibited, and when the polymer composition is applied, excellent coating film formation characteristics can be exhibited.

[0174] Meanwhile, in the present invention, NCO% can be obtained by neutralizing the isocyanate group with an excess of 2N amine and then back-titrating with 1N hydrochloric acid.

[0175] The content of unreacted diisocyanate remaining based on the total weight of solids in the above polyisocyanate composition is 1% by weight or less, or 0.5% by weight or less, or 0.3% by weight or less, and thus, superior stability can be exhibited by significantly reducing the content of unreacted diisocyanate compared to conventional methods.

[0177] The above polyisocyanate composition may further include, if necessary, additives such as internal release agents, UV absorbers, polymerization initiators, heat stabilizers, color correctors, chain extenders, crosslinking agents, light stabilizers, and fillers, and the content thereof may be appropriately determined within a range that does not impair the coloring and discoloration inhibition properties of the polymer composition.

[0179] The above-described polyisocyanate composition can be used in a wide range of fields due to its excellent physical properties, and among these, it can be used as a tack or adhesive due to the excellent adhesive strength of the polyisocyanate composition.

[0181] The operation and effects of the invention will be described in more detail below through specific embodiments. However, these embodiments are merely examples of the invention and do not define the scope of the invention.

[0183] [Preparation Example - Preparation of Xylene Diisocyanate Composition]

[0184] Preparation Example 1

[0185] 437 kg of 1,2-dichlorobenzene with a purity of 99.83% and 45.5 kg (10.4 wt%) of m-XDA (meta-xylenediamine) with a purity of 99.5% were added to a reactor and stirred for 3 hours while adding 27 kg of anhydrous hydrochloric acid at room temperature (about 24°C) and atmospheric pressure (1 atm). As the temperature rose while adding the anhydrous hydrochloric acid, the salt reaction began, and the salt reaction was carried out by maintaining the reactor at atmospheric pressure (1 atm) and about 80°C for about 4 hours to obtain an amine salt compound.

[0186] Next, 40 kg of phosgene was initially injected into the reactant containing the above amine salt compound, and the temperature was raised to 120°C. Subsequently, 300 kg of phosgene was slowly injected into the reactor, and the reactor temperature was maintained at 120–135°C. 20 hours were elapsed from the time of phosgene injection until the end of the reaction. After the solution became clear, the inside of the reactor was cooled to 80°C and cooled by blowing in nitrogen. A xylene diisocyanate composition with phosgene removed was obtained.

[0188] Preparation Example 2

[0189] The process was carried out with the same amount as in Preparation Example 1, but when injecting phosgene, an educator nozzle was installed at the injection end. Phosgene was injected at 80°C after the crude reaction was finished, and the temperature was raised to 120°C, while the internal temperature was controlled by adjusting the phosgene flow rate. The total reaction time was 15 hours.

[0191] Preparation Example 3

[0192] The process was carried out with the same amount as in Preparation Example 2, but when injecting phosgene, an educator nozzle was installed at the injection end, and after the ionization reaction was completed, the temperature was raised to 120°C to inject phosgene, and the reactor temperature was maintained at 120–135°C. The total reaction time was 12 hours.

[0194] [Experimental Example 1: Analysis of Preparation Conditions for Isocyanate Compounds]

[0195] Gas chromatography (GC) analysis was performed on the xylene diisocyanate composition containing the isocyanate compound prepared in the above preparation example, and the GC area (%) for m-XDI, excluding the solvent, was shown in Table 1 as m-XDI purity.

[0196] <GC 분석 조건>

[0197] The phosgene reaction product was analyzed using GC. The GC used for the analysis was HP-6890, and detection was performed using FID. The column used was DB-17 (30 m * 0.25 mm * 0.5 µm), the carrier gas was nitrogen (1.0 mL / min), the injection volume was 1 μl, and the oven temperature was 80℃ -> 5℃ / min -> 160℃ (8 min) -> 20℃ / min -> 280℃ (18 min).

[0198] Split-by: Pulsed Splitless Method

[0199] IMBAl detection method: SIM (monitoring ions: m / z 161, 132)

[0200] CMBI Detection Method: SIM (Monitoring Ions: m / z 181, 146)

[0201] IMBAl detection method: SIM (monitoring ions: m / z 158, 116)

[0203] division Preparation Example 1 Preparation Example 2 Preparation Example 3 Phosgene reaction time (hr) 20 15 12 m-XDI Purity (%) 98.3 98.5 98.9

[0204] As can be seen in Table 1 above, it was confirmed that there are differences in reaction efficiency due to variations in reaction uniformity depending on the method of injecting phosgene in the phosgene reaction. In particular, when a mixing eductor for phosgene is used as in Preparation Examples 2 and 3, it was confirmed that the phosgene and the amine salt compound are uniformly mixed, resulting in a shorter reaction time and increased purity of m-XDI.

[0206] [Examples and Comparative Examples - Preparation of Polyisocyanate Compositions]

[0207] Example 1

[0208] Preparation of isocyanate compounds

[0209] A reaction mixture containing an isocyanate compound was prepared according to Preparation Example 3 (m-XDA: 10.4 wt%), the solvent was removed from the reaction solution from which phosgene had been removed through vacuum distillation, and the product was purified through fractional distillation under reduced pressure and thin-film distillation to obtain a xylene diisocyanate composition containing an isocyanate compound.

[0211] Preparation of polyisocyanate compositions

[0212] 300g of a xylene diisocyanate composition containing the isocyanate compound (meta-xylene diisocyanate) prepared above was added to a flask under a nitrogen atmosphere. The temperature of the flask was raised to 70°C and maintained, and 26.7g of trimethylolpropane (TMP) was added dropwise as a polyhydric alcohol. Subsequently, the reaction temperature was maintained at 70°C until the isocyanate group concentration in the flask reached a calculated value of 33%.

[0213] After the reaction was completed, the resulting reaction product was purified using a thin film evaporator (TFE) to separate unreacted XDI, and the mixture was diluted with ethyl acetate to a solid content of 75 wt% to obtain a polyisocyanate composition.

[0215] Example 2

[0216] In the above Example 1, a polyisocyanate composition was obtained in the same manner except that m-XDA was changed to 8 wt%.

[0218] Example 3

[0219] In Example 1 above, a polyisocyanate composition was obtained in the same way except that m-XDA was changed to 5 wt%.

[0221] Example 4

[0222] In the above Example 1, an isocyanate compound and a polyisocyanate composition were obtained in the same manner as in Example 1, except that m-XDA with a purity of 99.83% was purified to 99.97% and used.

[0224] Example 5

[0225] In Example 4 above, a polyisocyanate composition was obtained in the same way except that the m-XDA was changed to 8 wt%.

[0227] Example 6

[0228] In Example 4 above, a polyisocyanate composition was obtained in the same way except that the m-XDA was changed to 5 wt%.

[0230] Comparative Example 1 (Direct Phosgenation Reaction)

[0231] 362 ml of 1,2-dichlorobenzene and 42.7 ml of phosgene were placed in a flask and placed into a reactor. The temperature was then cooled to -10°C to -15°C, and 31.5 ml of m-XDA (8 vol%) was slowly added. After the addition of the amine compounds was complete, the reactor temperature was heated to 130°C, and the direct phosgenesis reaction was carried out by maintaining the reactor temperature at 125°C to 135°C until the reaction solution became clear. After the reaction solution became clear, nitrogen was introduced into the reactor to reduce the temperature to 80°C. Subsequently, the solvent was removed by vacuum distillation, and the product was purified by fractional distillation under reduced pressure to obtain a composition containing an isocyanate compound and a polyisocyanate composition.

[0233] Comparative Example 2 (Control of reactant purity)

[0234] In Example 1 above, a polyisocyanate composition was obtained by the same method except that m-XDA with a purity of 98.0% was used.

[0236] Comparative Example 3 (Solvent Control)

[0237] In the above Example 1, a polyisocyanate composition was obtained in the same manner, except that n-amyl acetate was used as the solvent.

[0239] Comparative Example 4 (Control of process conditions for salt reaction - pressure)

[0240] In the above Example 1, 0.5 to 1.02 kgf / cm² at room temperature during the salt reaction 2 A polyisocyanate composition was obtained using the same method, except that it was changed to

[0242] Comparative Example 5 (Control of process conditions for salt reaction - temperature)

[0243] In Example 1 above, the reaction was carried out by heating the reactor to a temperature of approximately 120°C during the salt reaction. As a result, the amount of XDA.HCl vaporized increased, and the amount of XDA.HCl salt precipitated in the reactor's condenser and line was large, making it impossible to obtain the reaction product. Consequently, the isocyanate composition could not be obtained.

[0245] Comparative Example 6 (Control of process conditions for salt reaction - temperature)

[0246] In the above Example 1, a polyisocyanate composition was obtained in the same manner, except that the temperature of the reactor was cooled to about 15±1℃ during the salting reaction.

[0248] [Experimental Example 2: Evaluation of Isocyanate Compounds]

[0249] Gas chromatography (GC) analysis was performed on the reaction mixture containing the isocyanate compound prepared in the above examples and comparative examples, and the results were shown in Table 2 as GC area (%).

[0250] <GC 분석 조건>

[0251] The GC used for analysis was HP-6890, and detection was performed using FID. The column used was DB-17 (30 m * 0.25 mm * 0.5 µm), the carrier gas was nitrogen (1.0 mL / min), the injection volume was 1 μl, and the oven temperature was 80℃ -> 5℃ / min -> 160℃ (8 min) -> 20℃ / min -> 280℃ (18 min).

[0253] <Unreacted XDA Content (%) After Salting>

[0254] After the ionization reaction was completed, a sample was taken, and the remaining XDA content was measured as GC area (%).

[0256] [Experimental Example 3: Analysis of Polyisocyanate Composition]

[0257] The polyisocyanate compositions prepared in the above examples and comparative examples were evaluated for color, NCO content, residual XDI content, and turbidity according to the method described below, and the results are shown in Table 2.

[0258] For the polyisocyanate composition sample prepared above, the color intensity was evaluated according to the APHA method at 25°C.

[0260] [Experimental Example 4: Evaluation of Optical Articles]

[0261] 20.8 g of a reaction mixture containing the isocyanate compounds prepared in the above examples and comparative examples, 0.04 g of zelec UN (Stepan), and 0.04 g of biosorb 583 (Sakai Chemical Industry Co., Ltd) were stirred in a flask at room temperature for about 20 minutes. Next, 0.002 g of dibutyltin chloride was added and stirred for 10 minutes, and 19.2 g of 2,3-bis(2-sulfanyl ethyl sulfanyl)propane-1-thiol was added to the mixture, and a mixture was prepared by degassing at 5 mbar and stirring for 1 hour.

[0262] This mixture was filtered through a 1 μm PTFE filter and then injected into a mold consisting of a glass mold and tape. The mold was placed in an oven, and a polymerization reaction was carried out for 20 hours while gradually increasing the temperature from 10°C to 120°C. After the polymerization was completed, the mold was removed from the oven and released to obtain a plastic lens. The obtained plastic lens was annealed at 120°C for 6 hours to produce a final optical lens sample.

[0263] For the optical lenses manufactured above, the degree of occurrence of cloudiness (transparency) was evaluated visually under various light source conditions according to the following evaluation criteria, and the results are shown in Table 2.

[0264] <Evaluation Criteria>

[0265] C(Clear): Transparent under both fluorescent and zirconium lamps

[0266] SH (Slightly lamp Haze): Transparent under fluorescent lights, but zirconium

[0267] Some turbidity was observed under the lamp.

[0268] LH (Lamp Haze): Transparent under fluorescent lights, but cloudiness is observed under zirconium lamps.

[0269] VH (Visual Haze): Haze was observed under both fluorescent and zirconium lamps.

[0270] YI: Yellowing observed on the lens

[0272] division m-XDA Purity (%) Unreacted XDA content (%) after salting Average particle size D[4,3](μm) after salting IMBAl content (%) CMBI content (%) IMBN content (%) IMBAl+CMBI+IMBN Content (%) Optical lens evaluation APHA after polyisocyanate manufacturing Example 1 99.83 0.18 6 0.11 0.13 0.06 0.30 C 14 Example 2 99.83 0.07 5 0.09 0.10 0.04 0.23 C 9 Example 3 99.83 0.19 4 0.08 0.06 0.02 0.16 C 6 Example 4 99.97 0.10 6 0.03 0.11 0.004 0.144 C 7 Example 5 99.98 0.08 6 0.009 0.067 0.0009 0.0769 C 6 Example 6 99.98 0.07 5 0.003 0.05 0.0008 0.0538 C 6 Comparative Example 1 99.83 - - 0.23 2.12 0.11 2.46 V.HY.I 106 Comparative Example 2 98 0.25 - 0.59 0.8 0.84 2.23 L.HY.I 40 Comparative Example 3 99.83 0.88 54 0.21 2.00 0.01 2.22 V.HY.I - Comparative Example 4 99.83 0.29 167 0.22 0.53 0.14 0.89 SH 36 Comparative Example 5 99.83 - - - - - - - - Comparative Example 6 99.83 0.49 38 0.25 0.67 0.11 1.03 SH 31

[0273] As can be seen in Table 1 above, in the case of the examples, high-purity xylene diisocyanate compounds could be produced in high yield through a simple manufacturing process that controls the purity of the reaction composition and simultaneously controls the content range of specific low-boiling point compounds among the byproducts. In addition, high-purity xylene diisocyanate could be produced by increasing process efficiency in the subsequent phosgene reaction by adjusting the salt reaction conditions of the amine compound to an appropriate range. Optical lenses using this material achieved superior transparency compared to the comparative example. Furthermore, it was confirmed that the color intensity according to the APHA method was low even after the preparation of a polyisocyanate composition using the xylene diisocyanate prepared according to the above method.

[0274] In the case of the comparative examples, as the process conditions changed, the amount of impurities increased or the particle size became non-uniform after the phosphogen reaction, which inhibited the phosgene reaction, and accordingly, it was confirmed that the quality of transparency, color, etc., which is considered when applying the product, was lowered compared to the examples.

Claims

Claim 1 A xylene diisocyanate composition comprising: a xylene diisocyanate compound; and a low-boiling point compound comprising isocyanomethylbenzaldehyde and isocyanomethylbenznitrile; wherein the low-boiling point compound is included in an amount of 0.0001 to 0.5% based on the total content of the composition. Claim 2 A xylene diisocyanate composition according to claim 1, wherein the low-boiling point compound is included in an amount of 0.0001 to 0.3% relative to the total content of the composition. Claim 3 A xylene diisocyanate composition according to claim 1, wherein the isocyanomethylbenzaldehyde is included in an amount of 0.0001 to 0.15% based on the total content of the composition. Claim 4 A xylene diisocyanate composition according to claim 1, wherein the isocyanomethylbenznitrile is included in an amount of 0.0001 to 0.1% with respect to the total content of the composition. Claim 5 In claim 1, the low-boiling point compound is a xylene diisocyanate composition further comprising chloromethylbenzyl isocyanate. Claim 6 In claim 5, the xylene diisocyanate composition wherein the chloromethylbenzyl isocyanate is included in an amount of 0.01 to 0.2% relative to the total content of the composition. Claim 7 A first step of obtaining an amine salt compound by reacting an amine compound with hydrogen chloride in a solvent at 20°C to 90°C and under atmospheric pressure; a second step of obtaining a reaction mixture containing a xylene isocyanate compound by reacting the amine salt compound with phosgene; A method for preparing a xylene diisocyanate composition, comprising a third step of removing a solvent and unreacted phosgene from the reaction mixture to prepare a xylene diisocyanate composition, wherein the solvent is one or more selected from the group consisting of chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, and 1,2,4-trichlorobenzene, the purity of the amine compound is 99.0% or higher, and the xylene diisocyanate composition comprises a low-boiling point compound in an amount of 0.0001 to 0.5% relative to the total content of the composition, and the low-boiling point compound comprises isocyanomethylbenzaldehyde and isocyanomethylbenznitrile. Claim 8 A method for preparing a xylene diisocyanate composition according to claim 7, wherein the low-boiling point compound is included in an amount of 0.0001 to 0.3% relative to the total content of the composition. Claim 9 A method for preparing a xylene diisocyanate composition, wherein the low-boiling point compound in claim 7 further comprises chloromethylbenzyl isocyanate. Claim 10 A method for preparing a xylene diisocyanate composition according to claim 7, wherein the amine compound is one or more selected from the group consisting of m-xylene diamine, p-xylene diamine, o-xylene diamine, and chlorides thereof. Claim 11 A method for preparing a xylene diisocyanate composition according to claim 7, wherein the amine compound is included in an amount of 1 to 20 weight% based on the total solvent content. Claim 12 A method for preparing a xylene diisocyanate composition according to claim 7, wherein the solvent is 1,2-dichlorobenzene. Claim 13 A method for preparing a xylene diisocyanate composition, wherein the second step is performed at 110°C to 160°C. Claim 14 A method for preparing a xylene diisocyanate composition according to claim 7, wherein the second step is performed by raising the temperature of an amine compound in a solvent to 110°C to 140°C and then adding a phosgene compound. Claim 15 A method for preparing a xylene diisocyanate composition according to claim 7, wherein the second step is performed by injecting phosgene through a mixing eductor into a reactor containing an amine salt compound. Claim 16 A method for preparing a xylene diisocyanate composition according to claim 7, wherein the third step further comprises a purification process after removing the solvent and unreacted phosgene from the reaction mixture. Claim 17 A first step of obtaining an amine salt compound by reacting an amine compound with hydrogen chloride in a solvent at 20°C to 90°C and under atmospheric pressure; a second step of obtaining a reaction mixture containing a xylene diisocyanate compound by reacting the amine salt compound with phosgene; and a third step of preparing a xylene diisocyanate composition by removing the solvent and unreacted phosgene from the reaction mixture. A method for preparing a polyisocyanate composition, comprising: a fourth step of synthesizing a polyisocyanate compound by polymerizing the xylene diisocyanate composition and a polyhydric alcohol; wherein the solvent is one or more selected from the group consisting of chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, and 1,2,4-trichlorobenzene, the purity of the amine compound is 99.0% or higher, and the xylene diisocyanate composition comprises a low-boiling point compound in an amount of 0.0001 to 0.5% relative to the total content of the composition, and the low-boiling point compound comprises isocyanomethylbenzaldehyde and isocyanomethylbenznitrile. Claim 18 A method for preparing a polyisocyanate composition according to claim 17, wherein the low-boiling point compound is included in an amount of 0.0001 to 0.3% relative to the total content of the composition. Claim 19 In claim 17, the method for preparing a polyisocyanate composition further comprising chloromethylbenzyl isocyanate as the low-boiling point compound. Claim 20 A method for preparing a polyisocyanate composition according to claim 17, wherein the polyhydric alcohol is a trihydric alcohol or a mixture of the trihydric alcohol and other polyhydric alcohols. Claim 21 A method for preparing a polyisocyanate composition according to claim 17, wherein the polyhydric alcohol comprises diethylene glycol, glycerol, trimethylolethane, trimethylolpropane, or a mixture thereof. Claim 22 A method for preparing a polyisocyanate composition according to claim 17, wherein the second step is performed in an inert gas atmosphere at a temperature range of 40°C to 100°C. Claim 23 A method for preparing a polyisocyanate composition according to claim 17, wherein the third step further comprises a purification process after removing the solvent and unreacted phosgene from the reaction mixture. Claim 24 A xylene diisocyanate composition according to any one of claims 1 to 6; and a polymerizable composition comprising one or more of i) a polyfunctional thiol-based compound and ii) a polyfunctional episulfide-based compound. Claim 25 An optical article comprising a polythiourethane polymer prepared from a polymerizable composition according to paragraph 24. Claim 26 In paragraph 25, the above optical article is an optical article that is an optical lens.

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