Method for reducing chlorinated derivatives content in isocyanate compositions

Abstract

The present invention relates to a method for reducing chlorinated derivatives content in a xylylene diisocyanate (XDI) composition generated in the process of producing XDI. In particular, the present invention relates to a method for reducing chlorinated derivatives content by converting, in an apparatus for producing XDI, chlorinated derivatives into non-chlorinated derivatives by means of the metallic surface or filler, and anhydrous protic acid.

Description

Method for reducing the content of chlorinated derivatives in isocyanate compositions

[0001] The present invention relates to a method for reducing the content of chlorinated derivatives contained in a xylylene diisocyanate composition generated in the process of manufacturing xylylene diisocyanate. In particular, the present invention relates to a method for reducing the content of chlorinated derivatives by converting chlorinated derivatives into non-chlorinated derivatives using a metal surface or metal filler and anhydrous protic acid in a xylylene diisocyanate manufacturing apparatus.

[0002] Xylylene diisocyanate (hereinafter abbreviated as 'XDI') is a specific diisocyanate with a methylene group on a benzene nucleus, and is an isocyanate that combines the characteristics of both aromatic and aliphatic isocyanates. It has the property of preventing yellowing, which is a disadvantage of aromatic diisocyanates, and is used as a raw material for urethane in non-yellowing paints, coatings, leather, adhesives, etc.

[0003] Although several methods have been proposed for producing XDI, the phosgene method is the most common. The phosgene method produces an isocyanate by reacting an organic primary amine with phosgene in an inert solvent. By passing phosgene gas through a suspension of an aromatic amine, its carbonate, or its hydrochloride in the solvent, an aromatic isocyanate can be converted relatively easily.

[0004] However, XDI, which is classified as an aliphatic isocyanate although it contains an aromatic ring, undergoes many side reactions during the reaction when isocyanate is manufactured by reacting xylylene diamine with phosgene, and various chlorinated impurities are generated as byproducts.

[0005] It is mentioned that the chlorinated impurities formed during the manufacture of the aliphatic isocyanate specified in Patent Document 1 are formed in an amount of 3 to 10 wt%, and sometimes reach up to 20 wt%. Therefore, if chlorinated impurities are contained in XDI, they affect the reaction between the isocyanate group and the active hydrogen-containing compound when manufacturing a polyurethane resin from XDI, thereby inhibiting the reaction. In addition, they promote the gelation of the initial polymer, which has a serious impact on the quality of optical lenses, such as yellowing, clouding, and striae. Therefore, these chlorinated derivatives can be said to be substances that should not be formed, or even if formed, must be removed by purification, etc.

[0006] The phosgene method can be divided into a direct method (Free-Salt Method) in which phosgene is directly reacted with the raw material amine, and a hydrochloride method (HCl-Salt Method) in which the raw material amine is converted to hydrochloride and then reacted with phosgene. Although the direct method is much simpler than the hydrochloride method, it is not commonly used because a significant amount of chlorinated derivatives is generated. For this reason, when producing chain or cyclic aliphatic isocyanates, the hydrochloride method is used in which the raw material amine is converted to hydrochloride and then reacted with phosgene to produce isocyanates. However, since a certain amount of chlorinated derivatives is generated even in the hydrochloride method, additional methods have been disclosed to reduce the content of impurities generated and obtain high-purity XDI.

[0007] Patent Document 2 discloses a method for producing isocyanates from chain-like or cyclic aliphatic amines by applying high pressure during the salt-forming reaction (a process for obtaining a slurry containing amine hydrochloride) to suppress the increase in the hydrochloride particle size. Furthermore, it discloses that the finer hydrochloride particles reduce the viscosity of the hydrochloride, thereby improving fluidity and lyophilization, thereby increasing the hydrochloride conversion rate during the phosgene reaction, thereby reducing the yield and chlorinated derivative production by 0.1 to 0.3 wt%.

[0008] Furthermore, in patent document 3, it is disclosed that a resin for optical materials obtained from an XDI composition having a concentration of a compound of chemical formula (5), which is a chlorinated derivative, of 0.2 ppm to less than 600 ppm has excellent yellowing resistance and high production efficiency.

[0009] Furthermore, Patent Document 4 also discloses that the presence of the chemical formula (7) compound among the chlorinated derivatives is required to have excellent discoloration resistance at 60 ppm or less. However, the chlorinated derivatives generated as major impurities in this isocyanate synthesis reaction serve as impurities that adversely affect the physical properties of optical lenses in polyurethane reaction applications. It is judged that the content of these impurities causes yellowing and does not have a positive effect on the product. In addition, these chlorinated derivatives should not be generated, or even if generated, they must be removed through purification or other means.

[0010] These prior technologies all have the problem of requiring precise process control and high-stage distillation columns for separation and purification, which reduces economic feasibility due to increased equipment costs and makes them unlikely to be commercialized.

[0011] The applicant of the present invention has developed a method for producing xylylene diisocyanate using a non-phosgene process to improve upon the shortcomings of the phosgene process (see Patent Document 5). This method involves producing biscarbamate using alkyl chloroformate or dialkyl carbonate, followed by thermal decomposition using a catalyst and a high-temperature solvent to decompose and remove alcohols with relatively low boiling points. However, this method has been difficult to apply industrially due to its high cost and the difficulty in mass production compared to the phosgene process.

[0012] Accordingly, the present applicant has proposed another prior art invention, a method for converting a chlorinated derivative into a non-chlorinated derivative by hydrogenation and an invention for an isocyanate composition containing such a non-chlorinated derivative (see Patent Document 6).

[0013] However, prior art also has limitations: The hydrogenation of chlorinated derivatives requires the use of expensive metal catalysts, such as palladium (Pd), in a hydrogen (H2) gas atmosphere, which carries the risk of gaseous explosion. Furthermore, this process requires additional hydrogen (H2) storage and supply equipment, as well as separate processes and equipment for hydrogenation. Consequently, this increases investment costs for the equipment and can reduce economic feasibility, necessitating the development of additional, improved processes.

[0014] (Prior art literature)

[0015] (Patent Document 1) Korean Patent Publication No. 10-1990-0012895 (published on September 3, 1990)

[0016] (Patent Document 2) Korean Patent Publication No. 10-2008-0015515 (published on February 19, 2008)

[0017] (Patent Document 3) Korean Patent Publication No. 2018-0104330 (published on September 20, 2018)

[0018] (Patent Document 4) Korean Patent Publication No. 2018-0127517 (published on November 28, 2018)

[0019] (Patent Document 5) Korean Patent Publication No. 2012-0111171 (published on October 10, 2012)

[0020] (Patent Document 6) Korean Patent Publication No. 2020-0113074 (published on October 6, 2020)

[0021]

[0022] Accordingly, the purpose of the present invention is to provide a new method capable of reducing the content of chlorinated derivatives by using a metal material surface or metal filler and a protic acid such as anhydrous HCl naturally generated during the reaction in an XDI manufacturing device.

[0023] The present inventors have carefully observed the reaction step and distillation step of XDI, and as a result, confirmed that some of the chlorinated derivatives contained in XDI are converted into non-chlorinated derivatives during the manufacturing process, and thus completed the present invention. The present invention relates to a method for converting a chlorinated derivative into a non-chlorinated derivative in a reactor or distillation device filled with a metal surface or a metal filler in an XDI manufacturing device. Therefore, the present invention can be directly applied in a reactor or distillation device filled with a metal surface or a metal filler in an XDI manufacturing device, and thus can bring about economic benefits in terms of industrialization such as reduction of process cost and improvement of high quality.

[0024] In order to achieve the above purpose, the present invention is a method for reducing the content of a chlorinated derivative in an XDI composition containing the chlorinated derivative represented by the following chemical formula (1) in a manufacturing device for xylylene diisocyanate (XDI),

[0025] A step in which the chlorinated derivative is converted into a non-chlorinated derivative of the following chemical formula (3) by a metal material surface or metal filler in the above manufacturing device and anhydrous protic acid;

[0026] Provided is a method for reducing the content of chlorinated derivatives, including:

[0027] Chemical formula (1); Chemical formula (3)

[0028] (Here, R1 is Cl or NCO, R2 is H or Cl, and R3 is H or NCO.)

[0029] In one embodiment, the manufacturing device of the present invention may be a metal reactor for manufacturing the XDI or a metal distillation device for distilling the composition of the XDI.

[0030] In another aspect, the present invention provides a method further comprising the step of separately dispensing the metal filler into a manufacturing device. Furthermore, the metal reactor may be a SUS (stainless steel) reactor.

[0031] In another aspect, the distillation apparatus in the present invention may be a distillation apparatus filled with a structured packing or random packing made of a metal material.

[0032] In another embodiment, the protic acid in the present invention may be selected from a monoprotic acid, a polyprotic acid, or a mixture thereof. The protic acid is preferably hydrogen chloride (HCl).

[0033] In another aspect, in the present invention, the metal may be at least one selected from transition metals within groups 3 to 12 of the periodic table. Preferably, the transition metal is at least one selected from the group consisting of Fe, Zn, Cu, Cr, Mn, Ni, Ag, Co, and Mo.

[0034] Meanwhile, in another aspect, in the present invention, the hydrogen chloride can be obtained from hydrogen chloride, a reaction by-product generated in the process of reacting an organic primary amine with a carbonylating agent to produce the XDI:

[0035] .

[0036] In the present invention, the carbonylation agent may be selected from phosgene, diphosgene, triphosgene, aliphatic or aromatic chloroformate compounds, or a combination thereof.

[0037] In another aspect, in the present invention, the hydrogen chloride is carbamoyl chloride (R-(NH-CO-Cl) as follows: n , n = 1 or 2) can be additionally obtained through the decomposition process:

[0038]

[0039] (Here, R1 and R2 are NCO or -NHCOCl, respectively).

[0040] In another embodiment, the content ratio of the non-chlorinated derivative in the present invention is in the range of 0.1 to 10,000 ppm. In addition, the content ratio of the chlorinated derivative is in the range of more than 0 to 3,500 ppm.

[0041] In another aspect, in the present invention, the content ratio of the XDI is in the range of 90 mass% or more.

[0042]

[0043] The method of the present invention can directly convert a chlorinated derivative into a non-chlorinated derivative within a reactor or distillation device filled with a metal material surface or a metal filler during the XDI manufacturing process. Accordingly, the process time for separation / purification can be shortened, thereby achieving a reduction in process costs, and a relatively high-quality product can be obtained, thereby providing competitiveness in terms of quality and price.

[0044] In order to reduce the formation of chlorinated derivatives in the reaction step of manufacturing an isocyanate, even if the isocyanate is synthesized directly without the complicated process of manufacturing a hydrochloride salt of xylenediamine (XDA), it is possible to easily convert it in situ into a non-chlorinated derivative. As a result, the present invention will be able to obtain a high-quality XDI composition, thereby enabling the production of high-quality optical resins or optical products at high cost.

[0045]

[0046] definition

[0047] All technical and scientific terms used in the description of the present invention have the same meaning as commonly understood by those skilled in the art to which this invention pertains, unless otherwise defined. All patent publications, application publications, and other publications cited as prior art are incorporated by reference in their entirety.

[0048] As used herein, the term 'combination' includes blends, mixtures, reaction products, and the like.

[0049] In addition, specific numerical values ​​such as mixing ratio (content ratio), physical property value, and parameter described in the present invention may be replaced with the upper limit value (a numerical value defined as “below” or “less than”) or the lower limit value (a numerical value defined as “not less than” or “exceeds”) of the corresponding mixing ratio (content ratio), physical property value, and parameter described in the present invention. Meanwhile, units such as “%” and ppm are based on mass unless specifically stated otherwise.

[0050] As used in the description and claims of the present invention, the singular form includes plural referents unless the context clearly dictates otherwise. Thus, for example, the term "isocyanate" is used to include monoisocyanates, diisocyanates, polyisocyanates, and mixtures thereof.

[0051] Unless otherwise stated, each material disclosed in the description of the present invention is commercially available, and their production methods are known to those skilled in the art. Furthermore, unless otherwise stated in the description of the present invention, all test standards are the most recent standards in effect at the time of this application.

[0052] The term 'chlorinated derivative' refers to an impurity containing chlorine resulting from a side reaction when isocyanates can be produced by the direct method, the hydrochloride method, or the carbonate method. In the present invention, examples of the chlorinated derivative include 3-chloromethylbenzyl isocyanate (chemical formula (6)), 1,3-xylylene dichloride (chemical formula (7)), 3-dichloromethylbenzyl isocyanate (chemical formula (8)), etc., which are represented by the following chemical formulas:

[0053] Chemical formula (6); Chemical formula (7); Chemical formula (8).

[0054] The term "non-chlorinated derivative" is used to mean a substance in which the above "chlorinated derivative" is converted to remove chlorine by replacing it with another atom or atomic group. In the present invention, non-chlorinated derivatives include compounds of the following chemical formula (3), methylbenzyl isocyanate of the following chemical formula (4), and xylene of the following chemical formula (5):

[0055]

[0056] Chemical formula (3); Chemical formula (4); Chemical formula (5).

[0057] (Here, R3 is H or NCO.)

[0058] The term 'carbonylation agent' refers to a chemical substance that causes a carbonylation reaction, which is a reaction that introduces a carbonyl group into organic compounds, etc. Carbonylation produces organic carbonyls, i.e. compounds containing a >C=O functional group, such as aldehydes, ketones, carboxylic acids, and esters. In particular, organic compounds containing carbonyl groups have unsaturated bonds, so they are highly reactive and can undergo highly selective reactions, and are therefore widely used in synthetic chemistry. Representative carbonylation agents used in the present invention include phosgene, diphosgene, triphosgene, and aliphatic or aromatic chloroformate compounds.

[0059] Hereinafter, the method for producing the isocyanate and the composition of the present invention will be described in detail.

[0060] First, the present invention relates to a method for converting a chlorinated derivative produced in the process of manufacturing an isocyanate into a non-chlorinated derivative by using a metal material surface or a metal filler and an anhydrous protic acid in an XDI manufacturing device as shown in the following reaction formula. In particular, the present invention aims to increase the purity of an isocyanate composition by easily reducing the content of chlorinated derivatives without going through a complicated, high-stage purification process and without separate processes and facilities through this method:

[0061]

[0062] (R1 is Cl or NCO, R2 is H or Cl, and R3 is H or NCO.)

[0063] As described above, since a certain amount of a chlorinated derivative known as the compound of chemical formula (1) is generated in the hydrochloride method, as in the direct method, it can be used to obtain XDI constituting the isocyanate composition of the present invention.

[0064] XDI (xylylene diisocyanate) has the following chemical formula (2):

[0065] Chemical formula (2).

[0066] It includes structural isomers 1,2-XDI (ortho-form), 1,3-XDI (meta-form), and 1,4-XDI (para-form), which can be used alone or in combination of two or more, preferably 1,3-XDI or 1,4-XDI, and more preferably 1,3-XDI.

[0067] Since the isocyanate composition obtained by the manufacturing method of the present invention is used as a reactant for obtaining a polymer compound such as polyurethane, the aliphatic amine used in the present invention is preferably a bifunctional or higher chain or cyclic aliphatic amine. The bifunctional or higher chain or cyclic aliphatic amine preferably used in the present invention is not particularly limited, but reference may be made to those mentioned in the above-mentioned prior patent documents. Representative examples thereof include chain aliphatic amines such as hexamethylenediamine, 2,2-dimethylpentanediamine, 2,2,4-trimethylhexanediamine, butenediamine, and xylylenediamine, and cyclic aliphatic amines such as bis(aminomethyl)cyclohexane, dicyclohexylmethanediamine, cyclohexanediamine, and bis(aminomethyl)norbornene.

[0068] The isocyanate obtained by reacting the above-mentioned chain or cyclic aliphatic diamine with phosgene will be determined depending on the reacting diamine, and reference may be made to those mentioned in the above-mentioned prior patent documents. Representative examples thereof include chain aliphatic isocyanates such as hexamethylene diisocyanate, 2,2-dimethylpentane diisocyanate, 2,2,4-trimethylhexane diisocyanate, butene diisocyanate, and xylylene diisocyanate; and cyclic aliphatic isocyanates such as bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane diisocyanate, cyclohexane diisocyanate, and bis(isocyanatomethyl)norbornene. Among the exemplary compounds obtained by the manufacturing method of the present invention, compounds particularly preferable for use in various optical devices include xylylene diisocyanate, bis(isocyanatomethyl)norbornene, hexamethylene diisocyanate, and bis(isocyanatomethyl)cyclohexane.

[0069] Phosgene gas, which can be used in the production of xylylene diisocyanate of the invention, is the common name for carbonyl chloride or carbonyldichloride (COCl2), and is a colorless gas at room temperature, with a freezing point of 127.84°C and a boiling point of 7.84°C, and is generally produced by using a catalytic reaction of high-purity carbon monoxide to form anhydrous chlorine gas. Phosgene substitutes and / or precursors used according to the present invention may include any phosgene equivalent, such as diphosgene, triphosgene, etc., and any combination thereof.

[0070] In the XDI manufacturing device used in the present invention, the metal material or metal filler within the device will be one or more metals selected from transition metals in groups 3 to 12 of the periodic table. Among the transition metals, it is preferable to use one or more types of the group consisting of Fe, Zn, Cu, Cr, Mn, Ni, Ag, Co, and Mo alone or in combination of two or more. Among these, stainless steel (stainless steel; SUS) is more preferable.

[0071] This SUS reacts with a chlorinated derivative together with an anhydrous protic acid to convert the chlorinated derivative into a non-chlorinated derivative. SUS is an abbreviation for Japanese standards according to JIS (Japanese Industrial Standards), and the standard in Korea is STS (steel type stainless). As a representative example, the SUS reactor can be selected from SUS 303, 304TP, 316, or 316L, but the present invention is not limited to these. The specifications for representative examples of SUS are shown in Table 1 below. The weight % of the chemical components shown here represents the content of components other than the iron (Fe) component, and the remaining weight % represents the content of iron.

[0072] (Table 1)

[0073]

[0074] Meanwhile, metal fillers can be divided into metal fillers that can be used in a reactor in an XDI manufacturing device and metal fillers that can be used in a distillation device. The metal filler that can be used in a reactor is sufficient as long as it is in the form of particles of a certain size that can be easily used in the reaction, and is not limited to the particle size or shape. As for the filler that can be used in a distillation device, structured packing or random packing can be used, but it is not limited thereto. The specific surface area of ​​the metal that constitutes the structured and random packing of the metal material is not particularly limited as long as it can react with a chlorinated derivative together with an anhydrous protic acid to convert the chlorinated derivative into a non-chlorinated derivative.

[0075] Structured packing is not limited to a specific product, but Mellapak™ is the most widely used worldwide. In particular, MellapakPlus™ is known as the latest generation of structured packing. It enhances the geometry of the existing Mellapak, resulting in a significantly lower pressure drop and a 50% increase in maximum capacity compared to the original. Random packing can be selectively used, such as rasching rings, pall rings, and saddles, based on factors such as theoretical plate height, pressure, material, and fouling, and is not specifically limited.

[0076] The protic acid that can be used in the present invention corresponds to an acid in the Brønsted-Lowry acid-base theory, which defines a proton donor as an acid, and is an extension of the acid in the generally used Arrhenius acid-base theory.

[0077] In the present invention, the monoprotic acid is hydrobromic acid (HBr), hydroiodic acid (HI), perchloric acid (HClO4), hydrochloric acid (HCl), chloric acid (HClO3), nitric acid (HNO3), iodic acid (HIO3), oxalic acid (H2C2O4), sulfurous acid (H2SO3), chlorous acid (HClO2), chloroacetic acid (CH2ClCOOH), hydrofluoric acid (HF), nitrous acid (HNO2), formic acid (HCOOH), benzoic acid (C6H5COOH), hydrazoic acid (HN3), acetic acid (CH3COOH), propionic acid (CH3CH2COOH), hypochlorous acid (HClO), hydrocyanic acid (HCN), It can be selected from the group consisting of trifluoroacetic acid (CF3COOH), etc.

[0078] In addition, the diprotic acid may be selected from the group consisting of sulfuric acid (H2SO4), oxalic acid (H2C2O4), carbonic acid (H2CO3), hydrogen sulfide (H2S), chromic acid (H2CrO4), terephthalic acid (HOOC-C6H4-COOH), butenedioic acid (HOOC-CH=CH-COOH), hydrogen tellurate (H2Te), selenium hydroxide (H2Se), etc. Furthermore, the triprotic acid may be selected from the group consisting of phosphoric acid (H3PO4), arsenic acid (H3AsO4), phosphorous acid (H3PO3), etc. These diprotic acids and triprotic acids may be collectively referred to as polyprotic acids.

[0079] In particular, in the present invention, some of the above monoprotic acids or diprotic acids are included, but are classified as super acids, such as fluoroantimonic acid (HSbF6), magic acid (HSO3F + SbF5), fluorosulfonic acid (HSO3F), and carborane acid [H(CHB 11 Cl 11 )], trifluoromethanesulfonic acid (CF3SO3H), perchloric acid (HClO4), chlorosulfonic acid (HSO3Cl), sulfuric acid (H2SO4), hydrofluoric acid (HF), etc. can also be used.

[0080] In the present invention, the presence or absence of a solvent may be selected and used depending on the convenience of the process. Furthermore, there are no particular restrictions on the solvent used. As an inactivating solvent, aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as octane and decane, alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, and ethylcyclohexane, halogenated aromatic hydrocarbons such as chlorotoluene, chlorobenzene, dichlorobenzene, dibromobenzene, and trichlorobenzene, nitrogen-containing compounds such as nitrobenzene, N,N-dimethylformamide, N,N-dimethylacetateamide, and N,N'-dimethylimidazolidinone, ethers such as dibutyl ether, ethylene glycol dimethyl ether, and ethylene glycol diethyl ether, for example, dibutyl ether, ethylene glycol dimethyl ether, and ethylene glycol diethyl Examples include fatty acid esters such as ethers, such as amyl formate, n-butyl acetate, isobutyl acetate, n-amyl acetate, isoamyl acetate, methylisoamyl acetate, methoxybutyl acetate, 2-ethoxyethyl acetate, sec-hexyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, benzyl acetate, ethyl propionate, n-butyl propinate, isoamyl propinate, ethyl acetate, butyl stearate, butyl lactate, and amyl lactate, and aromatic carboxylic acid esters such as methyl salicylate, dimethyl phthalate, and methyl benzoate, and these may be used alone or in combination of two or more. Preferably, halogenated aromatic hydrocarbons may be mentioned, and more preferably, chlorobenzene and dichlorobenzene may be mentioned.

[0081] Meanwhile, the chlorinated derivatives included in the XDI composition of the present invention include, as described above, chloromethylbenzyl isocyanate (chemical formula (6)), xylylene dichloride (chemical formula (7)), dichloromethylbenzyl isocyanate (chemical formula (8)), etc., and may be present alone or in combination of two or more types.

[0082] Meanwhile, the non-chlorinated derivative may be methylbenzyl isocyanate (chemical formula (4)) or xylene (chemical formula (5)). The compound of chemical formula (4) of the present invention, like the structural isomers of XDI, includes structural isomers 1,2-methylbenzyl isocyanate, 1,3-methylbenzyl isocyanate, and 1,4-methylbenzyl isocyanate, and may exist alone or in combination of two or more, preferably 1,3-methylbenzyl isocyanate, 1,4-methylbenzyl isocyanate, and more preferably 1,3-methylbenzyl isocyanate. In addition, in the case of xylene, it includes structural isomers 1,2-xylene, 1,3-xylene, and 1,4-xylene, and may exist alone or in combination of two or more, preferably 1,3-xylene, 1,4-xylene, and more preferably 1,3-xylene.

[0083] The XDI composition of the present invention may contain methylbenzyl isocyanate, and when it exceeds 10,000 ppm, the physical properties of the lens, such as heat resistance, may deteriorate. The content of methylbenzyl isocyanate is 0.1 ppm to 10,000 ppm, 0.1 ppm to 5,000 ppm, preferably 0.1 ppm to 3,000 ppm, and more preferably 0.1 ppm to 1,000 ppm, based on the total mass of the XDI composition. In addition, a trace amount of a chlorinated derivative may remain after conversion to methylbenzyl isocyanate. When the chlorinated derivative exceeds 3,500 ppm in the presence of methylbenzyl isocyanate, the yellowness of the lens may increase. The content of the chlorinated derivative relative to the total mass of the XDI composition is in the range of more than 0 to 3,500 ppm or less, more than 0 to 3,000 ppm or less, more than 0 to 2,000 ppm or less, preferably more than 0 to 1,500 ppm or less, and more preferably more than 0 to 1,000 ppm or less.

[0084] In addition, the method for producing the above isocyanate composition may further include a reaction step of reacting an amine or a salt thereof with phosgene in a solvent to obtain a reaction product including an isocyanate compound; a degassing step of removing a gas phase from the reaction product; a desolvation step of recovering a solvent from the reaction product; a low-boiling substance removal step of removing a low-boiling substance (including a monoisocyanate such as (chloromethyl)benzyl isocyanate) from the reaction product from which the solvent has been removed; and a high-boiling substance removal step of removing a high-boiling substance (including an oligomer including a polymer higher than a dimer or trimer of an isocyanate) from the reaction product from which the low-boiling substance has been removed. In this way, the present invention may further include a step of separating the non-chlorinated derivative produced in the distillation column from the XDI composition by simple distillation so that the content ratio of the non-chlorinated derivative becomes a desired composition ratio.

[0085] Meanwhile, the process for converting a chlorinated derivative into a non-chlorinated derivative of the present invention can be divided into a reaction step and a distillation step, and can be performed alone or in parallel. The temperature of the process for converting a chlorinated derivative into a non-chlorinated derivative is not particularly limited, but is in the range of 10 to 200 o It can be done in C, preferably 100 to 180 o C, more preferably 110 to 160 o C. If the temperature is too low, the reaction rate is low and the removal rate of the chlorinated derivative is low, and if the temperature is too high, there is a disadvantage in that the viscosity of the solution increases significantly, such as the formation of oligomers.

[0086] Meanwhile, the isocyanate composition of the present invention can be provided as a monomer raw material for manufacturing an optical polymerization composition by polymerizing with a polyol / polythiol monomer. Although not directly addressed in the present invention, the optical polymerization composition can contain the isocyanate composition monomer and the polyol / polythiol monomer in a mixed state or in a separate state. That is, within the polymerization composition, the isocyanate composition monomer and the polyol / polythiol monomer can be in a mixed state in contact with each other, or in a separate state so as not to contact each other.

[0087] As a polyol component used in an optical polymerizable composition, for example, low molecular weight polyols and high molecular weight polyols can be mentioned. The polyols can be used alone or in combination of two or more. As a polythiol component, for example, aliphatic polythiols, aromatic polythiols, heterocycle-containing polythiols, aliphatic polythiols containing sulfur atoms in addition to a mercapto group, aromatic polythiols containing sulfur atoms in addition to a mercapto group, heterocycle-containing polythiols containing sulfur atoms in addition to a mercapto group, etc. can be mentioned.

[0088] In addition, the optical polymerizable composition may further include additives such as an internal release agent, an ultraviolet absorber, a near-infrared absorber, a polymerization initiator, a heat stabilizer, a color corrector, a chain extender, a crosslinking agent, a light stabilizer, an antioxidant, a filler, etc., as needed.

[0089] [Analysis method]

[0090] 1) Content of 1,3-dichloromethylbenzyl isocyanate (DCI, chemical formula (8))

[0091] Using the compound of chemical formula (7) with a purity of 99 mol% manufactured by the synthetic method specified in the prior patent document as a standard material, the compound was analyzed by gas chromatography under the specified conditions, and a calibration curve was created from the area value of the obtained gas chromatogram to perform quantification.

[0092] 2) Content of 1,3-xylylene diisocyanate (XDI, chemical formula (2))

[0093] The gas chromatography was analyzed under the conditions specified in the prior art patent document, and a calibration curve was created for the obtained gas chromatogram to quantify the result.

[0094] 3) Content of 3-chloromethylbenzyl isocyanate (CBI, chemical formula (6))

[0095] The gas chromatography was analyzed under the conditions specified in the prior art patent document, and a calibration curve was created for the obtained gas chromatogram to quantify the result.

[0096] 4) Content of 3-methylbenzyl isocyanate (MBI, chemical formula (4))

[0097] Using methylbenzyl isocyanate (reagent, Sigma-aldrich) with a purity of 98% as a standard material, the content of methylbenzyl isocyanate in the compositions of each example and comparative example was calculated in the same manner as the measurement method of XDI.

[0098]

[0099] The following synthetic examples and working examples are carried out by exploring various laboratory-scale processes according to the factory scale and limitations of the factory scale.

[0100] 1. Synthesis of XDI and preparation of XDI composition containing chlorinated derivatives

[0101] (Synthesis Example 1)

[0102] 23.4 kg of o-dichlorobenzene and 4.7 kg of bis(trichloromethyl)carbonate were dissolved in a 30 L glass reaction vessel equipped with a reflux condenser. Then, a solution of 1.3 kg of m-xylylenediamine dissolved in 1.3 kg of o-dichlorobenzene was slowly added to the reaction vessel at 60°C or lower. The temperature was raised to 160°C and the reaction was carried out for 4 hours while controlling the evolved hydrogen chloride gas. During the temperature increase, a solution of bis(trichloromethyl)carbonate dissolved in o-dichlorobenzene was additionally slowly added and stirred smoothly. After the reaction was completed, the reactor was purged with nitrogen to remove unreacted phosgene and hydrogen chloride gas, and the resulting solution was subjected to a desolvation and de-low boiling point process to obtain XDI having a chlorinated derivative content of 3120 ppm.

[0103] (Synthesis Example 2)

[0104] In Synthesis Example 1, 200 g of SUS316 pieces were added before adding m-xylylenediamine, and the reaction was continued under the same conditions. After completion of the reaction, the resulting solution was analyzed, and it was confirmed that 1790 ppm of methylbenzyl isocyanate, a non-chlorinated derivative represented by chemical formula (3), was produced.

[0105] Through Synthesis Example 2, it was confirmed that a non-chlorinated derivative represented by chemical formula (3) is produced when HCl, a by-product of the phosgene reaction, and a metal filler are present.

[0106]

[0107] 2. Manufacturing of XDI in large-scale production facilities equipped with distillation units filled with structured packing made of metal material.

[0108] In actual large-scale production of XDI, the conversion of chlorinated derivatives of XDI obtained from crude XDI obtained through phosgene reaction in a glass line (G / L) reactor into non-chlorinated derivatives using a distillation device filled with structured packing made of SUS material was observed.

[0109] [Example 1]

[0110] 2.0 tons (tons) of a crude XDI composition (acidity 2570 ppm, as HCl) prepared in the same manner as in Synthesis Example 1 was placed in 12 m 3 After introduction into the reactor, the internal temperature of the reaction was raised to 150°C under high vacuum. Reflux was performed at this temperature. The content of the chlorinated derivative before and after reflux was compared. The results are shown in Table 2.

[0111] (Table 2)

[0112]

[0113] Here, (1) CBI: chloromethyl benzyl isocyanate; (2) DCI: chloromethyl benzyl isocyanate; (3) MBI: methyl benzyl isocyanate

[0114] Through Example 1, it was confirmed that a chlorinated derivative was converted into a non-chlorinated derivative during reflux in a distillation apparatus filled with a structured packing made of metal material.

[0115]

[0116] 3. Investigation of the conversion behavior of chlorinated derivatives into non-chlorinated derivatives by adding SUS316 to the XDI composition obtained in Synthesis Example 1.

[0117] In order to investigate the behavior of conversion of chlorinated derivatives to non-chlorinated derivatives in the presence of metal materials, XDI manufactured in Synthesis Example 1 was used, and the behavior of conversion of chlorinated derivatives to non-chlorinated derivatives was investigated in Examples 2 to 10 by varying the reaction temperature, SUS316 input amount, reaction time, acidity content, etc. The acidity (HCl) of the XDI obtained in Synthesis Example 1 was basically adjusted to 3,200 ppm, and XDI with acidities of 200 and 6,500 ppm were manufactured separately to examine the effect of acidity.

[0118] [Example 2]

[0119] 50 g of XDI obtained in Synthesis Example 1 and 5 g of SUS316 mesh pieces (1 cm x 1 cm) were placed in a 100 ml glass flask equipped with a reflux condenser. While stirring, the inside of the reactor was sufficiently purged with nitrogen. After completion of nitrogen purging, the reaction temperature inside the reactor was raised to 130 ℃. The temperature was maintained for 5 hours, and the changes in the contents of chlorinated and non-chlorinated derivatives before and after the reaction were observed. The contents of chlorinated and non-chlorinated derivatives are shown in Table 4.

[0120] [Examples 3 and 4]

[0121] The experiment was conducted under the same conditions as Example 2, but changes according to the reaction temperature were observed.

[0122] [Examples 5 and 6]

[0123] The experiment was conducted under the same conditions as Example 3, but changes according to the amount of SUS316 pieces added were observed.

[0124] [Examples 7 and 8]

[0125] The experiment was conducted under the same conditions as Example 3, but changes according to reaction time were observed.

[0126] [Examples 9 and 10]

[0127] The experiment was conducted under the same conditions as Example 3, but changes according to acidity content were observed.

[0128] [Comparative Example 1]

[0129] Observations were made under the same conditions as Example 3 without adding SUS 316 pieces to the glass reactor.

[0130] (Table 3)

[0131]

[0132] (Table 4)

[0133]

[0134] In the above Examples 2 to 10, although there was a difference in the CBI removal rate, it was confirmed that the content of CBI, a chlorinated derivative, decreased while MBI, a non-chlorinated derivative, increased regardless of the conditions due to the introduction of SUS316. On the other hand, in Comparative Example 1, when the SUS316 piece was not present, MBI, a non-chlorinated derivative, was not observed. In the above examples, the CBI removal rate was the best under the conditions of Example 3. This confirmed that in order to increase the CBI removal rate, the reaction temperature, a certain condition of SUS input amount, and acidity are required.

[0135]

[0136] 4. Investigation of the conversion behavior of chlorinated derivatives to non-chlorinated derivatives according to the type of metal in the XDI composition obtained in Synthesis Example 1.

[0137] In order to investigate the behavior of conversion of chlorinated derivatives into non-chlorinated derivatives according to the type of metal, XDI manufactured in Synthesis Example 1 was used, and the conversion was performed by changing the type of metal as follows. In Examples 11 to 19, the behavior of conversion of chlorinated derivatives into non-chlorinated derivatives was observed. The acidity (HCl) of the XDI obtained in Synthesis Example 1 was basically adjusted to 3,200 ppm.

[0138] [Examples 11 to 19]

[0139] The experiment was conducted under the same conditions as Example 3, but the changes in the content of chlorinated and non-chlorinated derivatives depending on the type of metal were observed. The contents of chlorinated and non-chlorinated derivatives are shown in Table 5.

[0140] (Table 5)

[0141]

[0142] In Examples 11 to 19, the results generally showed that the chlorinated derivative CBI was converted to the non-chlorinated derivative MBI. However, the conversion range varied significantly depending on the type of metal. In the case of Fe, the CBI removal rate was 72%, showing that among the metals, the chlorinated derivative CBI was converted to the non-chlorinated derivative MBI the most.

[0143]

[0144] 5. Preparation and evaluation of optical lenses from XDI compositions

[0145] The XDI composition containing 430 ppm of chlorinated derivative and 2184 ppm of non-chlorinated derivative obtained from Example 3 was distilled through a high vacuum distillation apparatus to obtain an XDI composition containing 310 ppm of chlorinated derivative and 110 ppm of non-chlorinated derivative. 52 g of the XDI composition thus prepared, 0.015 g of dibutyltin dichloride, 0.12 g of internal release agent (Zelec-UN, Stepan), and 0.08 g of ultraviolet absorber were stirred and mixed at room temperature for 1 hour, and then 48 g of 2,3-bis(2-mercaptoethylthio)propane-1-thiol was charged to prepare a polymerizable composition.

[0146] The above polymerizable composition was stirred under reduced pressure for 1 hour to remove air bubbles and filtered through a 1 μm Teflon filter. Thereafter, it was injected into a mold made of a glass mold and tape, and polymerized in an oven at a temperature gradually increased to 120°C for 20 hours. After cooling, it was demolded from the mold to obtain a resin (plastic). The obtained resin was further annealed at 120°C for 2 hours. As a result of examining the physical properties of the optical lens manufactured in this way, the refractive index was 1.6656, the yellowness was 1.20, the heat resistance was 88°C, and it also showed good results with respect to cloudiness and striae.

[0147] Considering that the refractive index, yellowness, and heat resistance of the currently commercialized product are 1.6656, 1.23, and 88°C, respectively, it can be seen that the composition manufactured in the present invention can also be sufficiently used as an optical lens material.

Claims

1. A method for reducing the content of a chlorinated derivative in an XDI composition comprising the chlorinated derivative represented by the following chemical formula (1) in a manufacturing device for xylylene diisocyanate (XDI), A step in which the chlorinated derivative is converted into a non-chlorinated derivative of the following chemical formula (3) by a metal material surface or metal filler in the above manufacturing device and anhydrous protic acid; A method for reducing the content of chlorinated derivatives, including: Chemical formula (1); Chemical formula (3) (Here, R1 is Cl or NCO, R2 is H or Cl, and R3 is H or NCO.) 2. A method according to claim 1, wherein the manufacturing device is a metal reactor for manufacturing the XDI or a metal distillation device for distilling the composition of the XDI.

3. A method according to claim 1, further comprising a step of separately administering the metal filler to a manufacturing device.

4. A method according to claim 2, characterized in that the metal reactor is a SUS (stainless steel) reactor.

5. A method according to claim 2, wherein the distillation device is a distillation device filled with a structured packing or random packing made of a metal material.

6. A method according to claim 1, wherein the protic acid is one selected from a monoprotic acid, a polyprotic acid, or a mixture thereof.

7. A method according to claim 1, wherein the protic acid is hydrogen chloride (HCl).

8. A method according to claim 1, wherein the metal is at least one selected from transition metals within groups 3 to 12 of the periodic table.

9. A method according to claim 8, wherein the transition metal is at least one selected from the group consisting of Fe, Zn, Cu, Cr, Mn, Ni, Ag, Co, and Mo.

10. In the 7th paragraph, the hydrogen chloride is obtained from hydrogen chloride, a reaction by-product generated in the process of reacting an organic primary amine with a carbonylating agent to manufacture the XDI. .

11. A method according to claim 10, wherein the carbonylation agent is selected from phosgene, diphosgene, triphosgene, an aliphatic or aromatic chloroformate compound, or a combination thereof.

12. In the 7th paragraph, the hydrogen chloride is carbamoyl chloride (R-(NH-CO-Cl) as follows n , n = 1 or 2) is additionally obtained through the decomposition process, method: (Here, R1 and R2 are NCO or -NHCOCl, respectively) 13. A method according to any one of claims 1 to 12, wherein the content ratio of the non-chlorinated derivative is 0.1 to 10,000 ppm.

14. A method according to any one of claims 1 to 12, wherein the content ratio of the chlorinated derivative is in the range of more than 0 to 3,500 ppm.

15. A method according to any one of claims 1 to 12, wherein the content ratio of XDI is 90 mass% or more.

Images