Method for producing polyvalent carbodiimide B

Abstract

The present invention provides a method for producing a polyvalent carbodiimide having a desired structure, wherein the amount of by-products is reduced and a carbodiimidization catalyst is not included. The present invention relates to a method for producing a polyvalent carbodiimide B, the method comprising: a step for forming uretonimine from a mixture including a polyvalent isocyanate and a carbodiimide A; a step for decomposing the uretonimine; and a step for removing a monovalent isocyanate a derived from the carbodiimide A by distillation, wherein the carbodiimide A is either or both of a monovalent carbodiimide and a polyvalent carbodiimide, the molar ratio of isocyanate functional groups and carbodiimide functional groups in the mixture including the carbodiimide A is 1 < NCO / NCN < 4 (except for NCO / NCN＝2.000), and a reaction rate in the step for removing the monovalent isocyanate a by distillation is 80% or more.

Description

[Technical Field]

[0001] The present invention relates to a method for producing polyvalent carbodiimide B. This application claims priority based on Japanese Patent Application No. 2022-148998, filed on September 20, 2022, the contents of which are incorporated herein by reference. [Background technology]

[0002] Carbodiimide compounds, particularly polyvalent carbodiimide compounds having multiple carbodiimide groups in the same molecule, are widely known for their applications as resin modifiers, crosslinking agents for aqueous resins, adhesives, etc. Thus, polyvalent carbodiimides used as resin modifiers, crosslinking agents for aqueous resins, adhesives, etc. require sophisticated molecular design, including monomer structure and degree of polymerization, depending on the application. Polyvalent carbodiimide compounds are generally produced by heating polyvalent isocyanates in the presence of a carbodiimide catalyst and undergoing a reaction accompanied by decarboxylation.

[0003] However, the polyvalent carbodiimide produced in this manner contains residual carbodiimidation catalyst, which can cause various problems when the product is made. First, as pointed out in Patent Document 1, increasing the amount of carbodiimidization catalyst added raises safety concerns. The phospholine catalysts commonly used in the production of polyvalent carbodiimides are organic phosphorus compounds and should be avoided for safety reasons.

[0004] Furthermore, as pointed out in Patent Document 2, the carbodiimidization catalyst remains active even after production. Therefore, if isocyanate groups remain in the polyvalent carbodiimide, the carbodiimidization reaction proceeds during storage, generating carbon dioxide. To prevent the generated carbon dioxide from increasing the internal pressure of the storage container, it must be released outside the system, which also affects product quality.

[0005] Furthermore, as pointed out in Patent Document 3, when a polyvalent carbodiimide is used as a resin modifier, the residual carbodiimide catalyst may have an adverse effect of promoting the generation of bubbles in the resin.

[0006] In light of the above, various efforts have been made to remove or inactivate the carbodiimidization catalyst in polyvalent carbodiimides. For example, Patent Document 4 proposes a method of using a catalyst in which a carbodiimidization catalyst is bound to a high-molecular-weight insoluble inorganic or organic matrix, and removing the catalyst after the reaction.

[0007] However, polycarbodiimides generally have high boiling points and are difficult to purify by distillation, so the carbodiimide catalyst and polycarbodiimide must be separated by filtration, making it difficult to completely avoid contamination of the polycarbodiimide with the carbodiimide catalyst.

[0008] In Patent Document 5, the carbodiimidization catalyst is removed by distillation purification. However, carbodiimidization catalysts generally have high boiling points, making distillation purification difficult. Furthermore, when heated at high temperatures, polyvalent carbodiimides react with each other or with isocyanates to form crosslinked structures. For this reason, they are not suitable for high-temperature heating, and it is difficult to completely remove the carbodiimidization catalyst.

[0009] Furthermore, in Patent Document 6, the carbodiimidation catalyst is inactivated. However, the inactivation is not complete, and the carbodiimidation catalyst itself remains, so this only solves some of the problems caused by the remaining carbodiimidation catalyst. Furthermore, the reagent used for inactivation can cause discoloration of the product, which can be a problem.

[0010] Therefore, the methods described in Patent Documents 4 to 6 have problems as methods for reducing the amount of carbodiimidation catalyst or for producing polyvalent carbodiimides that do not contain a carbodiimidation catalyst.

[0011] In view of the above circumstances, there is a demand for a method for producing a polyvalent carbodiimide compound in which the amount of carbodiimide catalyst is reduced or which does not contain a carbodiimide catalyst. To obtain such polycarbodiimides, we focused on the exchange reaction that occurs between carbodiimide functional groups and isocyanate functional groups.

[0012] For example, Patent Document 7 describes that a uretonimine functional group is formed from a carbodiimide functional group and an isocyanate functional group, and that the reverse reaction shows an exchange reaction. Patent Document 7 also describes a method for producing a polyvalent carbodiimide by exchanging a residue that bonds to a carbodiimide functional group with a residue that bonds to an isocyanate functional group.

[0013] This method is advantageous in that it does not involve the residual phosphorus catalyst or the use of highly toxic reagents, nor does it involve the risk of residual residues, which are common in the other methods mentioned above. On the other hand, from a practical standpoint, a method for producing polycarbodiimides is required that produces few by-products and that can economically obtain polycarbodiimides with the desired degree of polymerization and structure.

[0014] For example, in Example 1 of Patent Document 7, to obtain a polyvalent carbodiimide, isocyanate functional groups derived from HDI (hexamethylene diisocyanate) are reacted with carbodiimide functional groups derived from DCC (N,N'-dicyclohexylcarbodiimide) at a molar ratio of NCO / NCN = 2, and then the remaining NCO is blocked with an excess of DCC. NCO represents the isocyanate functional group, and NCN represents the carbodiimide functional group.

[0015] However, in the method disclosed in Patent Document 7, the degree of polymerization becomes infinite when the stoichiometric reaction proceeds, making it difficult to control the degree of polymerization of the polycarbodiimide from the amount charged. In addition, monofunctional carbodiimides are generally expensive and more toxic than polycarbodiimides, making it necessary to recover and remove the monofunctional carbodiimides. When an excess of monovalent carbodiimide is used, it is necessary to heat the product at a high temperature to separate it by distillation. However, since polyvalent carbodiimides and monofunctional carbodiimides are generally thermally unstable, heating at a high temperature produces by-products, making it impossible to obtain a polyvalent carbodiimide having the desired molecular weight, and in the worst case, problems such as gelation or discoloration of the product can occur. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] Special Publication No. 2012-530743 [Patent Document 2] Japanese Unexamined Patent Publication No. 48-35242 [Patent Document 3] Patent No. 6250682 [Patent Document 4] Patent No. 5041794 [Patent Document 5] Patent No. 3452079 [Patent Document 6] Patent No. 5113996 [Patent Document 7] U.S. Patent No. 3,267,137 Summary of the Invention [Problem to be solved by the invention]

[0017] The present invention aims to produce a polycarbodiimide having a desired structure with reduced by-products and free from a carbodiimidization catalyst. [Means for solving the problem]

[0018] As a result of extensive research, the present inventors have found that by mixing specific raw materials in a specific mixing ratio and reacting them under specific conditions, a polyvalent carbodiimide having a desired degree of polymerization and structure with a small amount of by-products can be obtained. The present invention relates to a method for producing a polyvalent carbodiimide that exchanges a residue that binds to a carbodiimide functional group with a residue that binds to an isocyanate functional group, and is a method for producing a polyvalent carbodiimide with reduced by-products generated.

[0019] That is, the present invention includes the following [1] to

[17] . [1] A method for producing a polyvalent carbodiimide B, comprising a step of forming a uretonimine from a mixture containing a polyvalent isocyanate and a carbodiimide A, a step of decomposing the uretonimine, and a step of removing a monovalent isocyanate a derived from the carbodiimide A by a distillation operation, wherein the carbodiimide A is either one or both of a monovalent carbodiimide and a polyvalent carbodiimide, and the molar ratio of the isocyanate functional group to the carbodiimide functional group in the mixture containing the carbodiimide A is 1 < NCO / NCN < 4 (excluding NCO / NCN = 2.000), and the reaction rate in the step of removing the monovalent isocyanate a by a distillation operation is 80% or more. [2] The method for producing a polyvalent carbodiimide B according to [1], wherein the polyvalent isocyanate is represented by the following general formula (1). [Chemical formula] [[ID=1-12]] (In the formula, R 1 is an organic group containing an integer number of carbon atoms in the range of 1 to 85 carbon atoms, and n1 is an integer of 2 to 12.) [3] The method for producing a polyvalent carbodiimide B according to [1] or [2], wherein the carbodiimide A is represented by the following general formula (2). [Chemical formula] (In the formula, R 2 , R 4 are each independently a monovalent organic group containing an integer number of carbon atoms in the range of 1 to 85 carbon atoms, and R 3 is a divalent or higher organic group containing an integer number of carbon atoms in the range of 1 to 85 carbon atoms that may have a branched structure. n2 is an integer of 1 or more. When n2 is 2 or more, a plurality of R 3 may each have a different structure.) [4] The method for producing a polyvalent carbodiimide B according to any one of [1] to [3], wherein the monovalent isocyanate a is represented by the following general formula (3): [ka] (In the formula, R 5 is an organic group containing an integer number of carbon atoms ranging from 1 to 85. [5] The method for producing polyvalent carbodiimide B according to [1] or [2], wherein the isocyanate functional group in the polyvalent isocyanate is bonded to any one of an aliphatic primary carbon, an aliphatic secondary carbon, and an aliphatic tertiary carbon. [6] A method for producing a polyvalent carbodiimide B according to [1] or [2], wherein the carbodiimide functional group in the carbodiimide A is bonded to any one of an aliphatic primary carbon, an aliphatic secondary carbon, and an aliphatic tertiary carbon. [7] A method for producing the polyvalent carbodiimide B according to any one of [1] to [6], comprising: a step of obtaining a prepolymer A represented by the following general formula (4) by reacting a polyvalent isocyanate with a monovalent carbodiimide; and a step of reacting the prepolymer A under either or both of a higher temperature condition and a reduced pressure condition than in the step of obtaining the prepolymer A. [ka] (In the formula, R 6 is an organic group derived from a monovalent carbodiimide, and R 7 is an organic group derived from a polyvalent isocyanate, n3 and n4 are each independently an integer, n3 is 1 or more, n3 + n4 is equal to the isocyanate valence of the polyvalent isocyanate, A is an organic group that bonds to the organic group derived from the polyvalent isocyanate, and when n4 is 2 or more, the multiple As may be different from one another. [8] The method for producing polycarbodiimide B according to [7], wherein in the step of obtaining prepolymer A, the reaction is carried out until the content of monocarbodiimide becomes less than 15% of the amount of charged substance. [9] The method for producing a polyvalent carbodiimide B according to [7] or [8], wherein in the step of reacting the prepolymer A, the reaction is carried out under conditions equal to or lower than the vapor pressure of the monovalent carbodiimide.

[10] A method for producing a polyvalent carbodiimide B, comprising the steps of: forming a uretonimine from a mixture containing a polyvalent isocyanate and a carbodiimide A; decomposing the uretonimine; and removing a monovalent isocyanate a derived from the carbodiimide A by a distillation operation, wherein the carbodiimide A is one or both of a monovalent carbodiimide and a polyvalent carbodiimide; the mixture of the polyvalent isocyanate and the carbodiimide A contains a monovalent isocyanate b, and the monovalent isocyanate b has a vapor pressure lower than the vapor pressure of the monovalent isocyanate a derived from the carbodiimide A.

[11] The method for producing polyvalent carbodiimide B according to

[10] , wherein the monovalent isocyanate b is a compound represented by the following general formula (IV-1) and / or the following general formula (IV-2): [ka] (In general formula (IV-1), R 8 is an organic group having 1 to 12 carbon atoms. [ka] (In general formula (IV-2), R 9 , R 10 represents an organic group, and Q represents a structure represented by the following general formulas (IV-2-1) to (IV-2-5). [ka] In the general formulae (IV-2-1) to (IV-2-5), an asterisk represents a bonding site with a functional group.

[12] The monovalent isocyanate b is a structure represented by the general formula (IV-2), and R 10 The method for producing polyvalent carbodiimide B according to

[10] or

[11] , wherein: [ka]

[13] The monovalent isocyanate b is a structure represented by the general formula (IV-2), and R 9 The method for producing polyvalent carbodiimide B according to

[10] or

[11] , wherein the polyvalent carbodiimide B has a polyalkylene oxide structure.

[14] A method for producing a polyvalent carbodiimide B, comprising: a step of forming a uretonimine from a mixture containing a polyvalent isocyanate and a carbodiimide A; a step of decomposing the uretonimine; and a step of removing a monovalent isocyanate a derived from the carbodiimide A by a distillation operation, wherein the carbodiimide A is one or both of a monovalent carbodiimide and a polyvalent carbodiimide; and after the step of removing the monovalent isocyanate a by a distillation operation, a step of reacting the remaining isocyanate functional group with a compound capable of reacting with an isocyanate functional group.

[15] A method for producing a polyvalent carbodiimide B, comprising: a step of forming a uretonimine from a mixture containing a polyvalent isocyanate and a carbodiimide A; a step of decomposing the uretonimine; and a step of removing a monovalent isocyanate a derived from the carbodiimide A by a distillation operation, wherein the carbodiimide A is either one or both of a monovalent carbodiimide and a polyvalent carbodiimide; and after the step of removing the monovalent isocyanate a by a distillation operation, a step of reacting the remaining uretonimine with a compound capable of reacting with the uretonimine.

[16] The method for producing the polyvalent carbodiimide B according to any one of [1] to

[15] , wherein a solvent is used in the step of removing the monovalent isocyanate a by distillation.

[17] The method for producing polyvalent carbodiimide B according to

[16] , wherein the vapor pressure of the solvent is lower than the vapor pressure of the monovalent isocyanate a and higher than the vapor pressure of the carbodiimide A. [Effects of the Invention]

[0020] According to the production method of the above aspect, in the production of a polyvalent carbodiimide having a target structure, it is possible to reduce the amount of by-products and produce a polyvalent carbodiimide that does not contain a carbodiimidization catalyst.

[0021] In this embodiment, when the NCN yield of the produced polycarbodiimide B is 80% or more, it is evaluated that the by-products are reduced. The NCN yield of the polycarbodiimide B is calculated by the following method.

[0022] (NCN yield) The NCN yield is calculated from the amount of carbodiimide functional groups in the mixture containing the polyvalent isocyanate and carbodiimide A: α, and the amount of carbodiimide functional groups in the polyvalent carbodiimide B: β, based on the following formula: NCN yield = β / α DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, an embodiment for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. The present embodiment is an example for explaining the present invention, and the present invention is not limited to the present embodiment. The present invention can be carried out by appropriately modifying it within the scope of its gist.

[0024] <Method of producing polyvalent carbodiimide B> The method for producing polyvalent carbodiimide B of this embodiment includes a step of forming uretonimine from a mixture containing polyvalent isocyanate and carbodiimide A, a step of decomposing the uretonimine, and a step of removing monovalent isocyanate a derived from carbodiimide A by a distillation operation. First, the product and raw materials produced by the method for producing polyvalent carbodiimide B of this embodiment will be described.

[0025] <Polyvalent carbodiimide compound B> The polyvalent carbodiimide compound B in the present invention is a product produced by the production method of the present invention. The polycarbodiimide compound B is a compound having two or more carbodiimide functional groups and one or more residues obtained by removing an isocyanate from a polyisocyanate in the same molecule. The polycarbodiimide compound B is not particularly limited except that it has two or more carbodiimide functional groups and one or more residues obtained by removing an isocyanate from a polyisocyanate in the same molecule, but is generally represented by the following general formula (B):

[0026] [ka] (In the formula, R 20 , R 23 are each independently a monovalent organic group containing an integer number of carbon atoms ranging from 1 to 85, and R 21 is a divalent or higher organic group containing an integer number of carbon atoms in the range of 1 to 85, which may have a branched structure. m is an integer of 1 or more. When m is 2 or more, multiple R 21 may have different structures.)

[0027] In the present invention, m in the general formula (B) is referred to as the degree of polymerization of the polyvalent carbodiimide B.

[0028] <Polyisocyanate> The polyisocyanate in the present invention refers to a compound having two or more isocyanate functional groups in the same molecule. The polyisocyanate is not particularly limited except that it has two or more isocyanate functional groups in the same molecule, and polyisocyanates represented by the following general formula (1) can be used.

[0029] [ka] (In the formula, R 1 is an organic group containing an integer number of carbon atoms ranging from 1 to 85, and n1 is an integer from 2 to 12.

[0030] In this embodiment, it is more preferable to use a polyisocyanate where n1=2 in order to prevent gelation during the reaction. On the other hand, it is more preferable to use a polyisocyanate where n1>2 or to use a polyisocyanate where n1>2 and a polyisocyanate where n=2 in combination in order to improve crosslinking performance when mixed with a coating material.

[0031] When a polyisocyanate having n1>2 is used as the isocyanate, it is preferable to add it in an amount that does not cause gelation.

[0032] The present inventors have confirmed the existence of a side reaction in the production process of polyvalent carbodiimides, in which isocyanate functional groups react with each other to form carbodiimide functional groups along with decarboxylation. When this reaction occurs, the number of carbodiimide functional groups increases compared to the number of carbodiimide functional groups contained in the feed, making it difficult to control the equivalent weight of the reaction.

[0033] On the other hand, it has been found that this reaction depends on the structure of the carbon to which the isocyanate functional group in the polyisocyanate is bonded, and can be suppressed in polyisocyanates having an isocyanate functional group bonded to a carbon with high electron density. From this perspective, polyisocyanates having an isocyanate functional group bonded to an aliphatic primary carbon, an aliphatic secondary carbon, or an aliphatic tertiary carbon are more preferred, polyisocyanates having an isocyanate functional group bonded to an aliphatic secondary carbon or an aliphatic tertiary carbon are even more preferred, and polyisocyanates having an isocyanate functional group bonded to an aliphatic tertiary carbon are even more preferred.

[0034] The aliphatic primary carbon mentioned above refers to a carbon atom bonded to one other carbon atom, characterized in that the one carbon atom is bonded to a carbon atom, hydrogen atom, oxygen atom, or nitrogen atom only through a single bond. As a specific example, when an isocyanate functional group is bonded to an asterisk in the following general formulae (II-4) and (II-5), the isocyanate functional group is considered to be bonded to an aliphatic primary carbon. The same applies to aliphatic secondary carbons and aliphatic tertiary carbons. The aliphatic secondary carbon refers to a carbon atom bonded to two other carbon atoms, characterized in that the two carbon atoms are bonded to a carbon atom, hydrogen atom, oxygen atom, or nitrogen atom only through a single bond. As a specific example, when an isocyanate functional group is bonded to an asterisk in the following general formulae (II-7) and (II-8), the isocyanate functional group is considered to be bonded to an aliphatic secondary carbon. The term "aliphatic tertiary carbon" refers to a carbon atom that forms bonds with three other carbon atoms, and the three carbon atoms are bonded to carbon atoms, hydrogen atoms, oxygen atoms, or nitrogen atoms only through single bonds. As a specific example, when an isocyanate functional group is bonded to an asterisk in the general formula (II-9) described below, the isocyanate functional group is considered to be bonded to an aliphatic tertiary carbon. As a specific example, the general formula (II-6) is considered to have both an isocyanate functional group bonded to an aliphatic primary carbon and an isocyanate functional group bonded to an aliphatic secondary carbon.

[0035] We have also confirmed that in the production process of polyvalent carbodiimides, the resulting carbodiimide functional groups form crosslinked structures, as shown in (I-1) to (I-4) below, either between themselves or between the resulting carbodiimide functional groups and isocyanate functional groups. When this reaction occurs, the number of carbodiimide functional groups contained in the feed decreases, making equivalent control difficult. If the reaction proceeds excessively, it may cause high viscosity or, in the worst case, gelation. In (I-1) to (I-4) below, "·" indicates a bond.

[0036] [ka]

[0037] On the other hand, it has been found that this reaction depends on the structure of the carbon to which the isocyanate functional group in the polyisocyanate is bonded, and can be suppressed in polyisocyanates having an isocyanate functional group bonded to a carbon with high steric hindrance. From this perspective, polyisocyanates having an isocyanate functional group bonded to an aromatic carbon, an aliphatic secondary carbon, or an aliphatic tertiary carbon are more preferred, polyisocyanates having an isocyanate functional group bonded to an aliphatic secondary carbon or an aliphatic tertiary carbon are even more preferred, and polyisocyanates having an isocyanate functional group bonded to an aliphatic tertiary carbon are even more preferred.

[0038] Specific examples of the isocyanate compound include polyisocyanates in which n1=2 in formula (1) and polyisocyanates in which n1>2 in formula (1).

[0039] For example, examples of polyvalent isocyanates in which n1=2 in formula (1) are isocyanates characterized in that an isocyanate functional group is bonded to an aliphatic hydrocarbon include dimethylene diisocyanate, trimethylene diisocyanate (each isomer), tetramethylene diisocyanate (each isomer), pentamethylene diisocyanate (each isomer), hexamethylene diisocyanate (each isomer), heptamethylene diisocyanate (each isomer), octamethylene diisocyanate (each isomer), diisocyanatocyclohexane, and the like. Diisocyanatodimethylhexane (each isomer), bisisocyanatomethylcyclohexane (each isomer), diisocyanic acid isophorone (each isomer), dicyclohexylmethane diisocyanate (each isomer), diisocyanatodimethylpropane (each isomer), diisocyanatodimethylpentane (each isomer), diisocyanatodimethylhexane (each isomer), diisocyanatodimethylheptane (each isomer), diisocyanatodimethyloctane (each isomer), diisocyanatodimethylnonane (each isomer), diisocyanatodimethyldecane (each isomer) , Diisocyanatomethylethylpropane (each isomer), Diisocyanatomethylethylbutane (each isomer), Diisocyanatomethylethylpentane (each isomer), Diisocyanatomethylethylhexane (each isomer), Diisocyanatomethylethylheptane (each isomer), Diisocyanatomethylethyloctane (each isomer), Diisocyanatodiethylpropane (each isomer), Diisocyanatodiethylpentane (each isomer), Diisocyanatodiethylhexane (each isomer), Diisocyanatodiethylheptane (each isomer) , diisocyanatodiethyloctane (each isomer), diisocyanatodiethylnonane (each isomer), xylylene diisocyanate (each isomer), tetramethylxylylene diisocyanate (each isomer), lysine methyl ester isocyanate, lysine ethyl ester isocyanate, lysine propyl ester isocyanate (each isomer), lysine butyl ester isocyanate (each isomer), lysine pentyl ester isocyanate (each isomer), lysine hexyl ester isocyanate (each isomer), and the like.

[0040] Examples of isocyanates characterized in that an isocyanate functional group is bonded to an aromatic hydrocarbon include diphenylmethane diisocyanate (each isomer), tolylene diisocyanate (each isomer), naphthalene diisocyanate (each isomer), etc. Also included are polyisocyanates where n1=2 obtained by crosslinking the polyisocyanates where n1=2 with a compound having a divalent active hydrogen group.

[0041] For example, examples of polyisocyanates where n1>2 in formula (1) include isocyanates characterized in that an isocyanate functional group is bonded to an aliphatic hydrocarbon, such as propane triisocyanate, butane triisocyanate (each isomer), pentane triisocyanate (each isomer), hexane triisocyanate (each isomer), heptane triisocyanate (each isomer), octane triisocyanate (each isomer), nonane triisocyanate (each isomer), and decane triisocyanate (each isomer). isomer), undecane triisocyanate (each isomer), dodecane triisocyanate (each isomer), tridecane triisocyanate (each isomer), tetradecane triisocyanate (each isomer), pentadecane triisocyanate (each isomer), hexadecane triisocyanate (each isomer), heptadecane triisocyanate (each isomer), octadecane triisocyanate (each isomer), nonadecane triisocyanate (each isomer), icosane triisocyanate (each isomer), and the like.

[0042] Examples of isocyanates characterized by an isocyanate functional group bonded to an aromatic hydrocarbon include polymeric MDI (each isomer), polyvalent isocyanates having one or more isocyanurate groups, biuret groups, and allophanate groups, and polyvalent isocyanates obtained by crosslinking polyvalent isocyanates with compounds having trivalent or higher active hydrogen groups.

[0043] In particular, examples of the structure of the residue obtained by removing the isocyanate from an easily available diisocyanate include the structures shown in the following general formulae (II-1) to (II-9).

[0044] [ka]

[0045] In the above general formulae (II-1) to (II-9), the asterisk represents the bonding site with the functional group, and n5 is an integer of 1 or more and 10 or less.

[0046] <Carbodiimide A> Carbodiimide A represents a compound having one or more carbodiimide functional groups in the same molecule, and is either or both of a monovalent carbodiimide and a polyvalent carbodiimide. A compound having one carbodiimide functional group in the same molecule is called a monovalent carbodiimide A, and a compound having two or more carbodiimide functional groups in the same molecule is called a polyvalent carbodiimide A. In the present invention, the carbodiimide A used as a raw material in the production process of polyvalent carbodiimide B is not particularly limited except that it has one or more carbodiimide functional groups in the same molecule, but among them, a compound represented by the following general formula (2) is preferably used.

[0047] [ka] (In the formula, R 2 , R 4 are each independently a monovalent organic group containing an integer number of carbon atoms ranging from 1 to 85, and R 3 is a divalent or higher organic group containing an integer number of carbon atoms in the range of 1 to 85, which may have a branched structure. n2 is an integer of 1 or more. When n2 is 2 or more, multiple R 3 may have different structures.)

[0048] The present inventors have confirmed that isocyanate functional groups react with each other to form carbodiimide groups along with decarboxylation in the production process of polyvalent carbodiimide B. When this reaction occurs, the number of carbodiimide functional groups increases based on the number of carbodiimide functional groups contained in the feed, making it difficult to control the equivalent of the reaction.

[0049] On the other hand, it has been found that this reaction depends on the structure of the carbon to which the carbodiimide functional group in carbodiimide A is bonded, and can be suppressed by appropriately selecting the structure of carbodiimide A having a carbodiimide functional group bonded to a carbon with high electron density. From this viewpoint, carbodiimides A having a carbodiimide functional group bonded to an aliphatic primary carbon, an aliphatic secondary carbon, or an aliphatic tertiary carbon are more preferred, carbodiimides A having a carbodiimide functional group bonded to an aliphatic secondary carbon or an aliphatic tertiary carbon are even more preferred, and carbodiimides A having a carbodiimide functional group bonded to an aliphatic tertiary carbon are even more preferred.

[0050] Here, it is presumed that the reason why carbodiimide A is involved in the decarboxylation reaction of the isocyanate functional group is that isocyanate a derived from carbodiimide A produced by the reaction is involved in the decarboxylation reaction.

[0051] We have also confirmed that crosslinked structures such as those shown in formulas (I-1) to (I-4) are formed between the generated carbodiimide functional groups or between the generated carbodiimide functional groups and isocyanate functional groups in the production process of polycarbodiimide B. When this reaction occurs, the amount of either or both of the carbodiimide functional groups and isocyanate functional groups contained in the feed becomes reduced, making it difficult to control the equivalent weight. Furthermore, if the reaction proceeds rapidly, it may cause an increase in viscosity or, in the worst case, gelation.

[0052] On the other hand, it has been found that this reaction depends on the structure of the carbon to which the carbodiimide functional group in carbodiimide A is bonded, and can be suppressed in carbodiimides A having a carbodiimide functional group bonded to a carbon with high steric hindrance. From this viewpoint, carbodiimides A having a carbodiimide functional group bonded to an aromatic carbon, an aliphatic secondary carbon, or an aliphatic tertiary carbon are more preferred, carbodiimides A having a carbodiimide functional group bonded to an aliphatic secondary carbon or an aliphatic tertiary carbon are even more preferred, and carbodiimides A having a carbodiimide functional group bonded to an aliphatic tertiary carbon are even more preferred.

[0053] Here, it is presumed that the reason why carbodiimide A is involved in the decarboxylation reaction of the isocyanate functional group is that isocyanate a derived from carbodiimide A produced by the reaction is involved in the decarboxylation reaction.

[0054] Specific examples of carbodiimide A include aliphatic primary carbodiimides such as N,N'-dihexylcarbodiimide, EDC (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride), and EDAC (1-ethyl-3-(-3-dimethylaminopropyl)carbodiimide hydrochloride).

[0055] Examples of the aliphatic secondary carbodiimide include N,N'-dicyclohexylcarbodiimide and N,N'-diisopropylcarbodiimide.

[0056] Examples of the aliphatic tertiary carbodiimide include N,N'-ditertiarybutylcarbodiimide.

[0057] Examples of aliphatic primary polyvalent carbodiimides include HDI-based polycarbodiimides, aliphatic secondary polyvalent carbodiimides include dicyclohexylmethane 4,4'-diisocyanate-based polyvalent carbodiimides, and aliphatic tertiary polyvalent carbodiimides include TMXDI-based polyvalent carbodiimides. Compared to polyvalent carbodiimides, monovalent carbodiimides are more easily available and are therefore more preferably used.

[0058] In particular, examples of the structure of the residue obtained by removing the carbodiimide group from an easily available monovalent carbodiimide include the structures shown in the following general formulae (III-1) to (III-6).

[0059] [ka]

[0060] In the above general formulas (III-1) to (III-6), the asterisk represents the bonding site with the functional group. n6 is an integer of 0 or more and 12 or less.

[0061] Next, each step of the method for producing the polyvalent carbodiimide B will be described.

[0062] [Step of forming uretonimine] In the present embodiment, the step of forming uretonimine is performed by mixing a polyvalent isocyanate and carbodiimide A and heating to a predetermined temperature. The temperature required for forming uretonimine varies depending on whether the carbon to which the isocyanate functional group binds is aromatic carbon, aliphatic primary carbon, aliphatic secondary carbon, or aliphatic tertiary carbon, and whether the carbon to which the carbodiimide functional group binds is aromatic carbon, aliphatic primary carbon, aliphatic secondary carbon, or aliphatic tertiary carbon. Uretonimine is formed in all combinations regardless of whether the carbon to which the isocyanate functional group binds and the carbon to which the carbodiimide functional group binds are any of the above. It is preferable that the isocyanate functional group in the polyvalent isocyanate and the carbodiimide functional group in carbodiimide A are each bonded to an aliphatic carbon, specifically, any of aliphatic primary carbon, aliphatic secondary carbon, and aliphatic tertiary carbon. Among them, in the combination of a polyvalent isocyanate in which the isocyanate functional group is bonded to an aliphatic primary carbon and carbodiimide A in which the carbodiimide functional group is bonded to an aliphatic primary carbon, uretonimine can be formed even at a low temperature near room temperature, which is suitable.

[0063] [[ID=十六]](Mixing ratio) In the present embodiment, the mixing ratio of the polyvalent isocyanate and carbodiimide A is such that the molar ratio of the isocyanate functional group (NCO) in the polyvalent isocyanate to the carbodiimide functional group (NCN) of carbodiimide A is 1 < NCO / NCN < 4 (however, NCO / NCN = 2.000 is excluded).

[0064] The molar ratio is determined according to the composition of the target polyvalent carbodiimide B, particularly the degree of polymerization. When reacting under the condition of NCO / NCN ≤ 1, an equivalent amount of carbodiimide A with respect to the isocyanate functional group is consumed, and they are incorporated into the product. Carbodiimide A is generally expensive, and from the perspective of improving the economy of the product where the usage amount can be reduced, the reaction is carried out under the condition of 1 < NCO / NCN.

[0065] Also, when reacting under the condition of NCO / NCN < 1, carbodiimide A that does not react with the isocyanate functional group remains in the system. The boiling point of carbodiimide A is high compared to the monovalent isocyanate a having a residue obtained by removing the carbodiimide functional group from carbodiimide A. Therefore, removal of excess carbodiimide A by distillation requires higher temperature conditions than monovalent isocyanate a, which may lead to an increase in by-products.

[0066] From the perspective of reducing by-products, the reaction is carried out under the condition of 1 < NCO / NCN. When aiming at the use of polyvalent carbodiimide B as a curing agent, the curing performance is improved by the large number of carbodiimide functional groups in polyvalent carbodiimide B. From such a perspective, it is more preferable to obtain polyvalent carbodiimide B having a number of carbodiimide functional groups equal to or more than the number of isocyanate functional groups of the polyvalent isocyanate. Therefore, it is more preferable to react under the condition of 1 < NCO / NCN.

[0067] Also, when reacting under the condition of NCO / NCN ≥ 4, the number of carbodiimide functional groups contained in one molecule may be 1 or less and may not have the characteristics of a polyvalent carbodiimide. From that perspective, NCO / NCN < 4 is set.

[0068] Also, although it is possible to react under the condition of NCO / NCN = 2.000, except for NCO / NCN = 2, that is, by setting the NCO / NCN ratio to 1 < NCO / NCN < 2 or 2 < NCO / NCN < 4, the production of polyvalent carbodiimide B having the desired degree of polymerization becomes easier. Also, by setting the NCO / NCN ratio to 1 < NCO / NCN < 2 or 2 < NCO / NCN < 4, side reactions can be suppressed. Note that the 2 in NCO / NCN=2 is not a significant digit, so you can remove the integer 2. If you consider significant digits, you can remove 2.000.

[0069] [Uretonimine decomposition process] The method for producing a polyvalent carbodiimide of the present invention includes a step of forming a uretonimine and then decomposing the resulting uretonimine. In the step of decomposing the uretonimine, a monovalent isocyanate a derived from polyvalent carbodiimide B and carbodiimide A is obtained.

[0070] The step of decomposing uretonimine is carried out by heating uretonimine to a predetermined temperature. The temperature required to decompose uretonimine varies depending on whether the isocyanate functional group in the polyisocyanate is bonded to an aromatic carbon, an aliphatic primary carbon, an aliphatic secondary carbon, or an aliphatic tertiary carbon, and whether the carbodiimide functional group in carbodiimide A is bonded to an aromatic carbon, an aliphatic primary carbon, an aliphatic secondary carbon, or an aliphatic tertiary carbon. However, uretonimine dissociates in all combinations of the carbon to which the isocyanate functional group and the carbon to which the carbodiimide functional group are bonded, regardless of which of the above-mentioned combinations is used.

[0071] Among these, the following are more preferable because uretonimine decomposes at lower temperatures: when the isocyanate functional group in the polyisocyanate is bonded to an aliphatic tertiary carbon and the carbodiimide functional group in carbodiimide A is bonded to any one of an aliphatic tertiary carbon, an aliphatic secondary carbon, and an aliphatic primary carbon; when the isocyanate functional group in the polyisocyanate is bonded to an aliphatic secondary carbon and the carbodiimide functional group in carbodiimide A is bonded to any one of an aliphatic tertiary carbon, an aliphatic secondary carbon, and an aliphatic primary carbon; and when the isocyanate functional group in the polyisocyanate is bonded to an aliphatic primary carbon and the carbodiimide functional group in carbodiimide A is bonded to any one of an aliphatic tertiary carbon and an aliphatic secondary carbon.

[0072] Furthermore, when the isocyanate functional group in the polyisocyanate is bonded to either an aliphatic tertiary carbon or an aliphatic secondary carbon, and when the carbodiimide functional group in carbodiimide A is bonded to either an aliphatic tertiary carbon or an aliphatic secondary carbon, the uretonimine decomposes at an even lower temperature, which is even more preferable. Furthermore, when the isocyanate functional group in the polyisocyanate is bonded to an aliphatic tertiary carbon, and when the carbodiimide functional group in carbodiimide A is bonded to an aliphatic tertiary carbon, the uretonimine decomposes at an even lower temperature, which is even more preferable.

[0073] In the process of forming uretonimine from a mixture containing a polyisocyanate and carbodiimide A, the process of decomposing the uretonimine, and the process of removing the monoisocyanate a derived from carbodiimide A by distillation, decarboxylation and the above-mentioned structures (I)-1 to (I)-4 may occur as side reactions.

[0074] In order to prevent such side reactions, it is more preferable to carry out the reaction under dilution with a solvent. The solvent to be used is not particularly limited as long as it has high solubility for the polyvalent isocyanate, carbodiimide A, and polyvalent carbodiimide B and does not react with the isocyanate functional group and the carbodiimide functional group, but aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, aprotic polar solvents, halogenated solvents, etc. are preferably used.

[0075] From the viewpoint of suppressing side reactions and obtaining a desirable carbodiimide B, the concentration of the raw material isocyanate and raw material carbodiimide, including the solvent, is preferably 10% by mass or more and 90% by mass or less, more preferably 30% by mass or more and 70% by mass or less, and particularly preferably 40% by mass or more and less than 60% by mass. If the raw material isocyanate and raw material carbodiimide concentrations are within these ranges, a sufficient reaction rate can be obtained and side reactions can be suppressed, which is more preferable.

[0076] [Step of distilling monovalent isocyanate a having a residue derived from carbodiimide A] The monovalent isocyanate a derived from the polyvalent carbodiimide A produced in the step of decomposing the uretonimine is removed by distillation.

[0077] <<Response rate>> The reaction rate in the present invention is the theoretical reaction rate of the amount of carbodiimide functional groups and isocyanate functional groups extracted as vapor when the amount of ... Unit price isocyanate a The amount of substance Mt and the amount actually extracted as steam Unit price isocyanate a The amount of substance Mr is calculated based on the following formula (5). Reaction rate=Mr / Mt ×100(5)

[0078] In the present invention, the distillation operation of the monovalent isocyanate a is preferably carried out at a high reaction rate in order to obtain a polyvalent carbodiimide B having a structure and degree of polymerization that are obtained as a result of a theoretical reaction. The reaction rate is preferably 80% or more, more preferably 90% or more, even more preferably 95% or more, and particularly preferably 99% or more.

[0079] Furthermore, the product of the isocyanate functional group concentration and the carbodiimide functional group concentration present in the reaction system decreases as the reaction rate increases. Since the isocyanate functional group and the carbodiimide functional group can form the structures shown in (I-3) and (I-4) above in addition to forming uretonimine, it is preferable that the product of the isocyanate functional group concentration and the carbodiimide functional group concentration be small, also from the viewpoint of preventing these side reactions. Maintaining the above reaction rate reduces the product of the isocyanate functional group concentration and the carbodiimide functional group concentration, which leads to the suppression of side reactions and is therefore more preferable.

[0080] (monovalent isocyanate a derived from carbodiimide A) The monovalent isocyanate a derived from carbodiimide A is not particularly limited except that it has one isocyanate functional group in the molecule bonded to a residue obtained by removing the carbodiimide functional group from carbodiimide A, but a compound represented by the following general formula (3) is preferably used.

[0081] [ka]

[0082] In general formula (3), R 5 is an organic group containing an integer number of carbon atoms ranging from 1 to 85.

[0083] Examples of the monovalent isocyanate a derived from carbodiimide A include phenyl isocyanate, methyl isocyanate, ethyl isocyanate, propyl isocyanate (each isomer), butyl isocyanate (each isomer), pentyl isocyanate (each isomer), hexyl isocyanate (each isomer), heptyl isocyanate (each isomer), octyl isocyanate (each isomer), nonyl isocyanate (each isomer), decyl isocyanate (each isomer), cyclopropyl isocyanate, cyclohexyl isocyanate, and 3-isocyanato-N,N'-dimethylpropan-1-amine.

[0084] In particular, examples of the structure of the residue obtained by removing the isocyanate functional group from the monovalent isocyanate a derived from the easily available carbodiimide A include the structures shown in the general formulae (III-1) to (III-6) above.

[0085] In the present invention, a solvent can be used in the step of removing the monovalent isocyanate a derived from carbodiimide A by distillation. The solvent used in this step is not particularly limited as long as it can dissolve the monovalent isocyanate a and prepolymer derived from carbodiimide A, as well as the resulting polyvalent carbodiimide B. However, in order to obtain a structure-controlled polyvalent carbodiimide B, it is desirable to use a solvent that does not have reactivity with isocyanate functional groups and carbodiimide functional groups. From this perspective, it is preferable to use a solvent that does not have an active hydrogen group.

[0086] When the uretonimine decomposition step and the distillation step are carried out simultaneously, it is desirable to use a solvent from the viewpoint of suppressing by-products. The solvent used in this case may be a high-boiling solvent that is not distilled by the distillation operation, or a low-boiling solvent that is distilled. On the other hand, when the solvent used is a low-boiling solvent that is distilled by the distillation operation, it is more preferable because by distilling it simultaneously with the monovalent isocyanate a derived from carbodiimide A, the distillation of the monovalent isocyanate a derived from carbodiimide A is promoted, thereby contributing to the promotion of the reaction.

[0087] Furthermore, when a solvent is used, the vapor pressure of the solvent is less than that of the monovalent isocyanate a and more than that of the carbodiimide A, so that the monovalent isocyanate a and the reaction product can be separated efficiently. This is preferable because it reduces by-products and coloration from the two viewpoints of shortening the reaction time and the solvent dilution effect, and also makes it possible to obtain a polyvalent carbodiimide with a more precisely controlled structure.

[0088] The monovalent isocyanate a derived from carbodiimide A obtained by distillation can be regenerated and reused using a carbodiimidation catalyst. In this case, it is preferable to reduce the amount of carbodiimidation catalyst remaining in the monovalent carbodiimide to a concentration that can withstand the production of carbodiimide composition B of this embodiment. From this perspective, the amount of carbodiimidation catalyst remaining in the raw material carbodiimide composition is preferably 0.02 mass% or less. The amount of carbodiimidation catalyst remaining can be quantified by any analytical method, such as gas chromatography, liquid chromatography, inductively coupled plasma atomic emission spectroscopy, or elemental analysis. For example, 3-methyl-1-phenyl-2-phospholene-1-oxide, which is used as a carbodiimidization catalyst, can be quantified using a Shimadzu GC system GC-2010, an Agilent Technologies dimethylpolysiloxane column DB-1 (length 30 m, inner diameter 0.250 mm, film thickness 1.00 μm), and a flame ionization detector (FID) under the following column temperature profile: hold at 50°C for 5 minutes, then increase the temperature to 200°C at a rate of 10°C / min, hold at 200°C for 5 minutes, and then increase the temperature to 300°C at a rate of 10°C / min. 3-Methyl-1-phenyl-2-phospholene-1-oxide can also be quantified using a Shimadzu LC-system LC-10AT, two GL Science Inertsil-ODS reversed-phase columns connected in series, and a refractive index detector (RID) under the following conditions: the developing solvent is a mixture of 0.1 w / v% aqueous phosphoric acid solution (liquid A) and acetonitrile (liquid B) in a volume ratio of 60:40, and the volume ratio is changed over 50 minutes to 10:90; the solvent flow rate is 2 mL / min; and the column temperature is 35°C.

[0089] [Step of forming prepolymer A] In the present embodiment, when a monovalent carbodiimide is used, it is preferable to include a step of obtaining a prepolymer A represented by the following general formula (4) by reacting a polyvalent isocyanate with a monovalent carbodiimide, from the viewpoint of maintaining the amount of carbodiimide contained in the reaction solution. This prepolymer A has a higher vapor pressure than the monovalent carbodiimide, and contributes to suppressing the monovalent carbodiimide from distilling from the top of the column during distillation.

[0090] [ka]

[0091] In general formula (4), R 6 is an organic group derived from monovalent carbodiimide, R 7 is an organic group derived from a polyvalent isocyanate, n3 and n4 are integers, n3 is 1 or more, n3 + n4 is equal to the isocyanate valence of the polyvalent isocyanate, A is an organic group that bonds to the organic group derived from the polyvalent isocyanate, and when n4 is 2 or more, As may be different from each other.

[0092] <Prepolymer A obtained by reacting polyisocyanate with monovalent carbodiimide> The prepolymer obtained by the reaction of a polyvalent isocyanate with a monovalent carbodiimide in the present invention refers to a compound having, in the same molecule, the structure of a residue obtained by removing a carbodiimide from a monovalent carbodiimide and the structure of a residue obtained by removing an isocyanate from a polyvalent isocyanate. The prepolymer is not particularly limited except that it has, in the same molecule, the structure of a residue obtained by removing a carbodiimide from a monovalent carbodiimide and the structure of a residue obtained by removing an isocyanate from a polyvalent isocyanate. A compound represented by the following general formula (4) is preferably used:

[0093] [ka]

[0094] In general formula (4), R6 is an organic group derived from a monovalent carbodiimide, R7 is an organic group derived from a polyvalent isocyanate, n3 and n4 are integers, n3 is 1 or more, n3 + n4 is equal to the isocyanate valence of the polyvalent isocyanate, A is an organic group that bonds to the organic group derived from the polyvalent isocyanate, and when n4 is 2 or more, As may be different from each other.

[0095] In the compound (4), R6 is a structure represented by any one of (III-1) to (III-6), and R 7 is a structure represented by any one of (II-1) to (II-9) above, and A has any one of the structures (II-1) to (II-9), each structure being linked via a carbodiimide functional group, and a structure having any one of the structures (III-1) to (III-6) or an isocyanate functional group at the terminal is particularly preferably used.

[0096] In the step of obtaining prepolymer A, the content of the monovalent carbodiimide is reduced relative to the amount of the charged substance. From the viewpoint of reducing the proportion of the monovalent carbodiimide withdrawn as the above in the distillation operation, the reduction of the monovalent carbodiimide is preferably carried out by reacting until the content of the monovalent carbodiimide is less than 15% of the amount of the charged substance, more preferably until it is less than 10%, even more preferably until it is less than 5%, and particularly preferably until it is less than 1%.

[0097] Furthermore, the degree of pressure reduction in the step of obtaining prepolymer A is desirably carried out at a level lower than the vapor pressure of either or both of the polyisocyanate and the monovalent carbodiimide. After obtaining the prepolymer, it is also possible to increase the degree of pressure reduction to a level lower than the vapor pressure of the monovalent carbodiimide. As described above, since the prepolymer has a higher vapor pressure than the monovalent carbodiimide, it is possible to set the degree of pressure reduction to a level lower than that of the monovalent carbodiimide. Furthermore, in order to increase the reaction rate, it is effective to increase the extraction efficiency of the monovalent isocyanate a derived from the monovalent carbodiimide.

[0098] In view of the above, the distillation conditions for obtaining polyvalent carbodiimide B are desirably as follows: in the step of obtaining a prepolymer, the distillation is carried out under conditions that are lower than the vapor pressure of either or both of the polyvalent isocyanate and the monovalent carbodiimide present in the reaction system and are equal to or higher than the vapor pressure of the monovalent isocyanate a derived from the monovalent carbodiimide; the monovalent isocyanate a is removed to obtain a prepolymer; and then the monovalent isocyanate a is removed under conditions that are equal to or higher than the vapor pressure of either or both of the polyvalent isocyanate and the monovalent carbodiimide present in the reaction system, and the reaction is carried out.

[0099] The distillation temperature may be selected depending on the thermal decomposition temperature of uretonimine and the amount of by-products produced. In terms of the amount of by-products produced, when the polyvalent isocyanate has an isocyanate functional group bonded to an aromatic carbon, the distillation temperature is preferably 180°C or lower, more preferably 160°C or lower, and particularly preferably 140°C or lower. When the polyvalent isocyanate has an isocyanate functional group bonded to an aliphatic primary carbon, the distillation temperature is preferably 200°C or lower, more preferably 180°C or lower, and particularly preferably 160°C or lower.

[0100] Furthermore, when the polyisocyanate has an isocyanate functional group bonded to an aliphatic secondary or tertiary carbon, the temperature is preferably 240°C or less, more preferably 220°C or less, and particularly preferably 200°C or less.

[0101] When carbodiimide A has a carbodiimide functional group bonded to an aromatic carbon, the reaction temperature is preferably 180°C or lower, more preferably 160°C or lower, and particularly preferably 140°C or lower.

[0102] When carbodiimide A has a carbodiimide functional group bonded to an aliphatic primary carbon, the temperature is preferably 200° C. or lower, more preferably 180° C. or lower, and particularly preferably 160° C. or lower. When polyvalent carbodiimide has a carbodiimide functional group bonded to an aliphatic secondary or tertiary carbon, the temperature is preferably 240° C. or lower, more preferably 220° C. or lower, and particularly preferably 200° C. or lower.

[0103] The mixture containing a polyvalent isocyanate and a polyvalent carbodiimide A preferably contains a monovalent isocyanate b having a vapor pressure lower than the vapor pressure of the monovalent isocyanate a derived from the carbodiimide A. This makes it possible to suppress side reactions and an increase in the molecular weight of the polyvalent carbodiimide B, thereby making it possible to suppress thickening and gelation.

[0104] The residues obtained by removing the isocyanate functional group from these monovalent isocyanates b are incorporated into the terminals of the polyvalent carbodiimide as the reaction progresses, and serve to terminate the polymerization reaction of the polyvalent carbodiimide. Therefore, it is more preferable that the mixture containing the polyvalent isocyanate and carbodiimide A contains a monovalent isocyanate b having a vapor pressure lower than the vapor pressure of the monovalent isocyanate a derived from carbodiimide A.

[0105] <<Monovalent isocyanate b having a vapor pressure lower than the vapor pressure of monovalent isocyanate a derived from carbodiimide A>> The monovalent isocyanate b having a vapor pressure lower than that of the monovalent isocyanate a derived from carbodiimide A is not particularly limited, but compounds represented by the following general formula are preferably used.

[0106] [ka]

[0107] In general formula (IV-1), R 8 is an organic group having 1 to 12 carbon atoms.

[0108] [ka]

[0109] In general formula (IV-2), R 9 , R 10 represents an organic group, and Q represents a structure represented by the following general formulas (IV-2-1) to (IV-2-5).

[0110] [ka]

[0111] In the general formulae (IV-2-1) to (IV-2-5), an asterisk represents a bonding site with a functional group.

[0112] Furthermore, in a mixture containing a polyvalent isocyanate and carbodiimide A, the monovalent isocyanate b having a vapor pressure less than that of the monovalent isocyanate a derived from carbodiimide A is not particularly limited, but from the viewpoint of ease of availability, a structure obtained by reacting the above-mentioned polyvalent isocyanate with a compound having reactivity with an isocyanate functional group is more preferred.

[0113] Among them, in view of ease of availability, R 8 is a structure represented by the general formulas (III-1) to (III-6), and in formula (IV-2), R 10 The structures represented by the above general formulae (II-1) to (II-9) are preferably used.

[0114] In formula (IV-2), R 9 can be selected arbitrarily, but from the viewpoint of improving the polarity of the reaction mixture and accelerating the reaction, it is preferable that a polar functional group is bonded. Among these, it is particularly preferable that the alkylene oxide has a polyalkylene oxide structure. Among polyalkylene oxide structures, polyethylene oxide, polypropylene oxide structures, and polyethylene oxide / polypropylene oxide copolymer structures are particularly preferable.

[0115] R having polyethylene oxide and polypropylene oxide structures 9 The structure can be represented by the following general formula (V-1).

[0116] [ka]

[0117] In general formula (V-1), an asterisk represents a bonding site with a functional group. 11 represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms, n7, n8, and n9 are integers of 0 or more, and n7+n8+n9 is 1 or more. The arrangement of the polyethylene oxide repeating units and polypropylene oxide repeating units can be selected arbitrarily, and they may be random copolymers or block copolymers. R 11 Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group (each isomer), a butyl group (each isomer), a pentyl group (each isomer), a hexyl group (each isomer), a heptyl group (each isomer), an octyl group (each isomer), a nonyl group (each isomer), a decyl group (each isomer), an undecyl group (each isomer), and a dodecyl group (each isomer).

[0118] [Step of reacting remaining isocyanate functional groups with a compound capable of reacting with isocyanate functional groups] After removing the monovalent isocyanate a derived from carbodiimide A by distillation to obtain polyvalent carbodiimide B, it is preferable to react the remaining isocyanate with a compound capable of reacting with isocyanate. This process reduces the amount of isocyanate remaining in polyvalent carbodiimide B, making it possible to suppress the formation of structures (I-3) and (I-4) formed by the reaction of the carbodiimide group with the isocyanate group. The remaining isocyanate may also contain monovalent isocyanate a. Compared to other isocyanate compounds such as polyvalent isocyanates, monovalent isocyanate a has a higher vapor pressure and may generate vapors harmful to the human body depending on the conditions of use. Therefore, it is more preferable to react the monovalent isocyanate a with a compound capable of reacting with isocyanate to reduce the amount of monovalent isocyanate a.

[0119] (Compounds that can react with isocyanates) The compound capable of reacting with isocyanate may be any compound having a reactive group capable of reacting with an isocyanate group, and examples thereof include carbodiimides, alcohols, phenols, thiols, amines, hydroxylamines, active methylenes, carboxylic acids, water, etc. Among these, compounds having higher reactivity with isocyanate functional groups than carbodiimide functional groups are more preferred, and from this viewpoint, alcohols, amines, oximes, and active methylenes are more preferred, alcohols, amines, and active methylenes are even more preferred, and alcohols are particularly preferred.

[0120] The alcohols are not particularly limited as long as they are aliphatic compounds having a hydroxyl group, and may be aliphatic compounds having one hydroxyl group in the molecule or aliphatic compounds having two or more hydroxyl groups in the molecule.

[0121] Specific examples of preferred alcohols include methanol, ethanol, propanol (each isomer), butanol (each isomer), pentanol (each isomer), hexanol (each isomer), octanol (each isomer), nonanol (each isomer), decanol (each isomer), undecanol (each isomer), dodecanol (each isomer), tridecanol (each isomer), tetradecanol (each isomer), pentadecanol (each isomer), hexadecanol (each isomer), heptadecanol (each isomer), octadecanol (each isomer), nonadecanol (each isomer), isomer), icosanol (each isomer), cyclopentanol, cyclohexanol, cycloheptanol, cyclooctanol, decahydronaphthalen-1-ol, decahydronaphthalen-2-ol, methylcyclopentanol (each isomer), ethylcyclohexanol (each isomer), propylcyclohexanol (each isomer), pentylcyclohexanol (each isomer), hexylcyclohexanol (each isomer), dimethylcyclohexanol (each isomer), methylethylcyclohexanol (each isomer), diethylcyclohexanol (each isomer) , methylpropylcyclohexanol (each isomer), ethylpropylcyclohexanol (each isomer), dipropylcyclohexanol (each isomer), methylbutylcyclohexanol (each isomer), ethylbutylcyclohexanol (each isomer), propylbutylcyclohexanol (each isomer), dibutylcyclohexanol (each isomer), trimethylcyclohexanol (each isomer), methyldiethylcyclohexanol (each isomer), dimethylethylcyclohexanol (each isomer), triethylcyclohexanol (each isomer), methyldipropyl butylcyclohexanol (each isomer), propylcyclohexanol (each isomer), ethyldipropylcyclohexanol (each isomer), diethylpropylcyclohexanol (each isomer), tripropylcyclohexanol (each isomer), methyldibutylcyclohexanol (each isomer), dimethylbutylcyclohexanol (each isomer), ethyldibutylcyclohexanol (each isomer), diethylbutylcyclohexanol (each isomer), propyldibutylcyclohexanol (each isomer), dipropylbutylcyclohexanol (each isomer),Alcohols having saturated hydrocarbon groups such as tributylcyclohexanol (each isomer); alcohols having unsaturated hydrocarbon groups such as 2-propen-1-ol, 2-buten-1-ol, 3-buten-1-ol, 2-penten-1-ol, 3-penten-1-ol, 4-penten-1-ol, 2-hexen-1-ol, 3-hexen-1-ol, 4-hexen-1-ol, 5-hexen-1-ol, and benzyl alcohol; 1-methoxyethanol, 1-ethoxyethanol, 1-propoxyethanol, and 1-butoxyethanol. , 1-pentoxyethanol, 1-hexoxyethanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-propoxy-2-propanol, 1-butoxy-2-propanol, 1-pentoxy-2-propanol, 1-butoxy-2-propanol, polyalkylene glycol monoalkyl ethers and other alcohols having an ether group; fluoromethanol, chloromethanol, bromomethanol, iodine-methanol, difluoromethanol, dichloromethanol, dibromomethanol, diiodine-methanol, trifluoromethanol, Methanol, trichloromethanol, tribromomethanol, triiodomethanol, 2-fluoroethanol, 2-chloroethanol, 2-bromoethanol, 2-iodoethanol, 2,2-difluoroethanol, 2,2-dichloroethanol, 2,2-dibromoethanol, 2,2-diiodoethanol, 2,2,2-trifluoroethanol, 2,2,2-trichloroethanol, 2,2,2-tribromoethanol, 2,2,2-triiodoethanol, 2,2,3,3,3-pentafluoropropanol, 2,2,3,3,3- Pentachloropropanol, 2,2,3,3,3-pentabromopropanol, 2,2,3,3,3-pentaiodopropanol, 2,2,2-trifluoro-1-trifluoromethylethanol, 2,2,2-trichloro-1-trichloromethylethanol, 2,2,2-tribromo-1-tribromomethylethanol, 2,2,2-triiodo-1-triiodomethylethanol, 1,1,1,3,3,3-hexafluoro-2-trifluoromethylpropanol, 1,1,1,3,3,3-hexachloro-2-trichloromethylpropanol,1,1,1,3,3,3-Hexabromo-2-tribromomethylpropanol, 1,1,1,3,3,3-hexaiodo-2-triiodomethylpropanol, 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, 2,2,3,3,4,4,5,5-octachloro-1-pentanol, 2,2,3,3,4,4,5,5-octabromo-1-pentanol, 2,2,3,3,4,4,5,5-octaiodo-1-pentanol, hexafluoroisopropanol, hexachloroisopropanol, hexabromoisopropanol Alcohols having a halogen group such as hexaiodoisopropanol, 2-fluorobenzyl alcohol, 2-chlorobenzyl alcohol, 2-bromobenzyl alcohol, 2-iodobenzyl alcohol, 3-fluorobenzyl alcohol, 3-chlorobenzyl alcohol, 3-bromobenzyl alcohol, 3-iodobenzyl alcohol, 4-fluorobenzyl alcohol, 4-chlorobenzyl alcohol, 4-bromobenzyl alcohol, and 4-iodobenzyl alcohol; hydroxy acid esters, methyl glycolate, ethyl glycolate, etc. , propyl glycolate (each isomer), butyl glycolate (each isomer), pentyl glycolate (each isomer), hexyl glycolate (each isomer), dodecyl glycolate (each isomer), methyl lactate, ethyl lactate, propyl lactate (each isomer), butyl glycolate (each isomer), pentyl glycolate (each isomer), hexyl glycolate (each isomer), dodecyl glycolate (each isomer), methyl tartronate, ethyl tartronate, propyl tartronate (each isomer), butyl tartronate (each isomer), pentyl tartronate (each isomer ), hexyl tartronate (each isomer), dodecyl tartronate (each isomer), methyl 2-hydroxybutyrate, ethyl 2-hydroxybutyrate, propyl 2-hydroxybutyrate (each isomer), butyl 2-hydroxybutyrate (each isomer), pentyl 2-hydroxybutyrate (each isomer), hexyl 2-hydroxybutyrate (each isomer), dodecyl 2-hydroxybutyrate (each isomer), methyl 3-hydroxybutyrate, ethyl 3-hydroxybutyrate, propyl 3-hydroxybutyrate (each isomer), butyl 3-hydroxybutyrate (each isomer), pentyl 3-hydroxybutyrate (each isomer),Hexyl 3-hydroxybutyrate (each isomer), dodecyl 3-hydroxybutyrate (each isomer), methyl 4-hydroxybutyrate, ethyl 4-hydroxybutyrate, propyl 4-hydroxybutyrate (each isomer), butyl 4-hydroxybutyrate (each isomer), pentyl 4-hydroxybutyrate (each isomer), hexyl 4-hydroxybutyrate (each isomer), dodecyl 4-hydroxybutyrate (each isomer), dimethyl malate, diethyl malate, dipropyl malate (each isomer), dipentyl malate (each isomer), dihexyl malate (each isomer), didodecyl malate (each isomer), trimethyl citrate, triethyl citrate, tripropyl citrate (each isomer), tributyl citrate (each isomer), tripentyl citrate (each isomer), trihexyl citrate (each isomer), tridodecyl citrate (each isomer), trimethyl isocitrate, triethyl isocitrate, tripropyl isocitrate (each isomer), tripentyl isocitrate (each isomer), triisocitrate Alcohols having a carbonyl group such as hexyl (each isomer), tridodecyl isocitrate (each isomer), hydroxy-2-propanone, hydroxy-2-butanone, hydroxy-2-pentanone, hydroxy-2-hexanone, hydroxy-3-butanone, hydroxy-3-pentanone, and hydroxy-3-hexanone; 2-(dimethylamino)ethanol, 3-(dimethylamino)propanol, 4-(dimethylamino)pentanol, and 5-(dimethylamino)hexanone. Examples of suitable alcohols include alcohols having an amino group such as ethanol, diols such as ethanediol, propanediol (each isomer), butanediol (each isomer), pentanediol (each isomer), hexanediol (each isomer), and polyalkylene glycols, triols such as propanetriol (each isomer), heptanetriol (each isomer), pentanetriol (each isomer), and hexanetriol (each isomer), and polyhydric alcohols such as pentaerythritol. Among these, alcohols having an ether group such as polyalkylene glycol monoalkyl ethers and diols such as polyalkylene glycols are more preferred from the viewpoint of improving the polarity of the reaction mixture and accelerating the reaction.

[0122] The amines are not particularly limited as long as they are compounds having an amino group, and may be compounds having one amino group in the molecule or compounds having two or more amino groups in the molecule.

[0123] Preferred amines include, for example, methylamine, ethylamine, propylamine (each isomer), butylamine (each isomer), pentylamine (each isomer), hexylamine (each isomer), heptylamine (each isomer), octylamine (each isomer), dimethylamine, methylethylamine, diethylamine, methylpropylamine (each isomer), ethylpropylamine (each isomer), dipropylamine (each isomer), methylbutylamine (each isomer), ethylbutylamine (each isomer), propylbutylamine (each isomer), dibutylamine (each isomer), methylpentylamine (each isomer), ethylpentylamine (each isomer), propylpentylamine (each isomer), butylpentylamine (each isomer), dipentylamine (each isomer), methylhexylamine (each isomer), isomer), ethylhexylamine (each isomer), propylhexylamine (each isomer), pentylhexylamine (each isomer), dihexylamine (each isomer), methylheptylamine (each isomer), ethylheptylamine (each isomer), propylheptylamine (each isomer), pentylheptylamine (each isomer), hexylheptylamine (each isomer), diheptylamine (each isomer ), methyloctylamine (each isomer), ethyloctylamine (each isomer), propyloctylamine (each isomer), pentyloctylamine (each isomer), hexyloctylamine (each isomer), heptyloctylamine (each isomer), dioctylamine (each isomer), didecylamine (each isomer), didodecylamine (each isomer), and other amine compounds having a saturated aliphatic hydrocarbon group;amines having a saturated aliphatic hydrocarbon group having an ether group, such as 2-methoxyethylamine, 2-propoxyethylamine, 2-butoxyethylamine, 2-pentoxyethylamine, 2-hexoxyethylamine, N-(2-methoxyethyl)methylamine, N-(2-ethoxyethyl)methylamine, N-(2-propoxyethyl)methylamine, N-(2-butoxyethyl)methylamine, N-(2-pentoxyethyl)methylamine, N-(2-hexoxyethyl)methylamine, N-(2-methoxyethyl)ethylamine, N-(2-ethoxyethyl)ethylamine, N-(2-propoxyethyl)ethylamine, N-(2-butoxyethyl)ethylamine, N-(2-pentoxyethyl)ethylamine, and N-(2-hexoxyethyl)ethylamine;Fluoromethylamine, chloromethylamine, bromomethylamine, iodomethylamine, difluoromethylamine, dichloromethylamine, dibromomethylamine, diiodomethylamine, trifluoromethylamine, trichloromethylamine, tribromomethylamine, triiodomethylamine, bis(fluoromethyl)amine, bis(chloromethyl)amine, bis(bromomethyl)amine, bis(iodomethyl)amine, bis(difluoromethyl)amine, bis(dichloromethyl)amine, bis(dibromomethyl)amine, bis(diiodomethyl)amine, bis(trifluoromethyl)amine, bis(trichloromethyl)amine, bis(tribromomethyl)amine, bis(triiodomethyl)amine, bis(2,2,2-trifluoroethyl)amine, bis(2,2,2-trichloroethyl)amine, bis(2,2,2-tribromoethyl)amine, bis(2,2,2-triiodoethyl)amine, bis(2,2,3,3,3 -pentafluoropropyl)amine, bis(2,2,3,3,3-pentachloropropyl)amine, bis(2,2,3,3,3-pentabromopropyl)amine, bis(2,2,3,3,3-pentaiodopropyl)amine, bis(2,2,2-trifluoro-1-trifluoromethylethyl)amine, bis(2,2,2-trichloro-1-trichloromethylethyl)amine, bis(2,2,2-tribromo-1-tribromomethylethyl)amine, bis(2,2, secondary amines having a halogen group, such as 2-triiodo-1-triiodomethylethyl)amine, bis(1,1,1,3,3,3-hexafluoro-2-trifluoromethylpropyl)amine, bis(1,1,1,3,3,3-hexachloro-2-trichloromethylpropyl)amine, bis(1,1,1,3,3,3-hexabromo-2-tribromomethylpropyl)amine, and bis(1,1,1,3,3,3-hexaiodo-2-triiodomethylpropyl)amine;Examples of suitable amines include amines having a carbonyl group, such as dimethyliminodiacetate, diethyliminodiacetate, dipropyliminodiacetate, dibutyliminodiacetate, dipentyliminodiacetate, dihexyliminodiacetate, N-methylglycine ethyl, and N-ethylglycine ethyl. Among these, amine compounds having a saturated aliphatic hydrocarbon group are more preferred due to their high reactivity with isocyanate functional groups. Alcohols having an ether group, such as polyalkylene glycol monoalkyl ether, and diols, such as polyalkylene glycols, are more preferred from the viewpoint of improving the polarity of the reaction mixture and accelerating the reaction.

[0124] Further, examples of amines other than the compounds exemplified above include pyrrolidine, methylpyrrolidine (each isomer), ethylpyrrolidine (each isomer), propylpyrrolidine (each isomer), butylpyrrolidine (each isomer), dimethylpyrrolidine (each isomer), methylethylpyrrolidine (each isomer), diethylpyrrolidine (each isomer), piperidine, methylpiperidine (each isomer), ethylpiperidine (each isomer), propylpiperidine (each isomer), butylpiperidine (each isomer), ), dimethylpiperidine (each isomer), methylethylpiperidine (each isomer), diethylpiperidine (each isomer), azepane, methylazepane (each isomer), ethylazepane (each isomer), propylazepane (each isomer), butylazepane (each isomer), dimethylazepane (each isomer), methylethylazepane (each isomer), diethylazepane (each isomer), imidazole, methylpiperazine, pyrrole, etc.; methylbenzylamine, ethylbenzylamine, propylbenzyl methylbenzylamine (each isomer), butylbenzylamine (each isomer), pentylbenzylamine (each isomer), hexylbenzylamine (each isomer), etc.; morpholine, methylmorpholine (each isomer), ethylmorpholine (each isomer), propylmorpholine (each isomer), butylmorpholine (each isomer), dimethylmorpholine (each isomer), methylethylmorpholine (each isomer), diethylmorpholine (each isomer), methylpropylmorpholine (each isomer), ethylpropylmorpholine Examples of the amines include amines such as methyl butyl morpholine (each isomer), dipropyl morpholine (each isomer), methyl butyl morpholine (each isomer), ethyl butyl morpholine (each isomer), propyl butyl morpholine (each isomer), and dibutyl morpholine (each isomer); divalent amines such as ethanediamine (each isomer), propanediamine (each isomer), butanediamine (each isomer), pentanediamine (each isomer), and hexanediamine (each isomer); and polyvalent amines such as polyethyleneimine.

[0125] [Hydroxylamines] The hydroxylamine is not particularly limited, and may be a hydroxylamine having one hydroxylamine structure in the molecule, or a hydroxylamine having two or more hydroxylamine structures in the molecule.

[0126] Examples of hydroxylamines having one hydroxylamine structure in the molecule include dimethylhydroxylamine, methylethylhydroxylamine, diethylhydroxylamine, methylpropylhydroxylamine (each isomer), ethylpropylhydroxylamine (each isomer), dipropylhydroxylamine (each isomer), methylbutylhydroxylamine (each isomer), ethylbutylhydroxylamine (each isomer), dibutylhydroxylamine (each isomer), N-hydroxysuccinimide, and N-hydroxyphthalimide.

[0127] Examples of active methylenes include dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone, isopropyl acetoacetate, di-sec-butyl malonate, di-tert-butyl malonate, di-tert-pentyl malonate, diisopropyl malonate, tert-butylethyl malonate, and isopropylethyl malonate.

[0128] Any reaction conditions can be selected for the step of reacting the remaining isocyanate functional groups with a compound reactive with the isocyanate functional groups. The reaction can be carried out in the presence or absence of a solvent and in the presence or absence of a catalyst. The reaction temperature can be selected as appropriate depending on the rate of formation of by-products consisting of isocyanate functional groups, carbodiimide functional groups, and isocyanate and carbodiimide functional groups, as well as the stability of the isocyanate-reactive compound. However, such side reactions can be suppressed by carrying out the reaction at 260°C or below.

[0129] Furthermore, when a compound having an active hydrogen group is used as the compound reactive with isocyanate, an appropriate catalyst can be used. The catalyst is not particularly limited as long as it can improve the reaction rate between the isocyanate and the active hydrogen group, and examples thereof include tin-containing catalysts and tertiary amines. Furthermore, an appropriate solvent can be used to uniformly carry out the reaction between the isocyanate and the compound having an active hydrogen group. The solvent used is not particularly limited as long as it has high solubility for the polyvalent carbodiimide and the compound having an active hydrogen group and does not react with the isocyanate and the carbodiimide, and examples thereof include aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, aprotic polar solvents, and halogenated solvents.

[0130] [Step of reacting the remaining uretonimine with a compound capable of reacting with uretonimine] The process preferably includes the steps of forming uretonimine from a mixture containing a polyvalent isocyanate and carbodiimide A, decomposing the uretonimine, and removing the monovalent isocyanate a derived from the carbodiimide A by distillation, wherein the carbodiimide A is either a monovalent carbodiimide or a polyvalent carbodiimide, or both. After the step of removing the monovalent isocyanate a by distillation, the process preferably includes the step of reacting the remaining uretonimine functional groups with a compound capable of reacting with the uretonimine functional groups. This step reduces the amount of uretonimine remaining in the polyvalent carbodiimide B, thereby preventing the formation of structures (I-3) and (I-4) formed by the reaction of the carbodiimide group with the isocyanate group. The remaining uretonimine functional groups may include uretonimine functional groups formed from the monovalent isocyanate a and a carbodiimide functional group. When a uretonimine functional group formed from a monovalent isocyanate a and a carbodiimide functional group reacts with a compound reactive with uretonimine, a compound is obtained in which the isocyanate group of the monovalent isocyanate a reacts with the compound reactive with uretonimine. The resulting compound is a low-molecular-weight compound, which functions as a plasticizer for the polyvalent carbodiimide B and improves drivability, making it preferable. For example, when the monovalent isocyanate a is cyclohexyl isocyanate and the compound reactive with uretonimine is 1-dodecylamine, the cyclohexyl isocyanate and 1-dodecylamine react to form a compound having a urea bond. The step of reacting the uretonimine functional group with a compound reactive with uretonimine functional group may be carried out simultaneously with or separately from the step of reacting the remaining isocyanate functional group with a compound reactive with isocyanate functional group. For example, when a compound having an active hydrogen group reacts with a uretonimine functional group, the compounds of the above general formulae (IV-2-1) to (IV-2-5) are obtained, and at the same time, a carbodiimide functional group is generated, improving the yield of NCN.The compound capable of reacting with a uretonimine functional group may be any compound having a reactive group capable of reacting with uretonimine, and examples thereof include alcohols, phenols, thiols, amines, active methylenes, etc. Among these, compounds having higher reactivity with an isocyanate functional group than a carbodiimide functional group are more preferred, and from this viewpoint, alcohols, thiols, amines, oximes, and active methylenes are more preferred, and alcohols, thiols, amines, and active methylenes are even more preferred.

[0131] <Other embodiments> The method for producing the polyvalent carbodiimide B of the present invention may be the following method for producing the polyvalent carbodiimide B 2 or method for producing the polyvalent carbodiimide B 3.

[0132] <Method 2 for producing polyvalent carbodiimide B> The method 2 for producing the polyvalent carbodiimide B includes the steps of forming a uretonimine from a mixture containing a polyvalent isocyanate and a carbodiimide A, decomposing the uretonimine, and removing the monovalent isocyanate a derived from the carbodiimide A by distillation. The carbodiimide A is either a monovalent carbodiimide or a polyvalent carbodiimide, or both.

[0133] In the method 2 for producing polycarbodiimide B, the mixture of polyisocyanate and carbodiimide A contains monoisocyanate b, which has a vapor pressure lower than that of monoisocyanate a derived from carbodiimide A. The explanation for monoisocyanate b is the same as in the above <<Monoisocyanate b having a vapor pressure lower than that of monoisocyanate a derived from carbodiimide A>>. This makes it possible to suppress side reactions and an increase in the molecular weight of polycarbodiimide B, thereby making it possible to suppress thickening and gelation.

[0134] <Method 3 for producing polyvalent carbodiimide B> The method 3 for producing the polyvalent carbodiimide B includes the steps of forming a uretonimine from a mixture containing a polyvalent isocyanate and a carbodiimide A, decomposing the uretonimine, and removing the monovalent isocyanate a derived from the carbodiimide A by distillation. The carbodiimide A is either a monovalent carbodiimide or a polyvalent carbodiimide, or both.

[0135] In the method 3 for producing polyvalent carbodiimide B, after the step of removing the monovalent isocyanate a by distillation, a step of reacting the remaining isocyanate functional groups with a compound capable of reacting with the isocyanate functional groups is included. The explanation for this step is the same as that in the above [Step of reacting the remaining isocyanate functional groups with a compound capable of reacting with the isocyanate functional groups].

[0136] <Vapor pressure> In this embodiment, the vapor pressure refers to the vapor pressure of the pure substance of the target compound at the reaction temperature of the step of removing the monovalent isocyanate a by distillation. For example, in the step of reacting prepolymer A, which is the step of removing the monovalent isocyanate a by distillation, the vapor pressure of the monovalent carbodiimide in the description that the reaction is carried out under conditions equal to or lower than the vapor pressure of the monovalent carbodiimide refers to the vapor pressure of the pure substance of the monovalent carbodiimide at the reaction temperature of the step of reacting prepolymer A, which is the distillation operation. The method further comprises the steps of forming uretonimine from a mixture containing a polyisocyanate and carbodiimide A, decomposing the uretonimine, and removing the monovalent isocyanate a derived from the carbodiimide A by distillation, wherein the carbodiimide A is either one or both of a monovalent carbodiimide and a polyvalent carbodiimide, the mixture of the polyisocyanate and the carbodiimide A contains a monovalent isocyanate b, and the monovalent isocyanate b has a vapor pressure lower than that of the monovalent isocyanate a derived from the carbodiimide A. In this description, the vapor pressure of the monovalent isocyanate b refers to the vapor pressure of the pure substance of the monovalent isocyanate b at the reaction temperature in the step of removing the monovalent isocyanate a derived from the carbodiimide A by distillation. The vapor pressure of the monovalent isocyanate a derived from carbodiimide A refers to the vapor pressure of the pure substance of the monovalent isocyanate a at the reaction temperature in the step of removing the monovalent isocyanate a derived from carbodiimide A by distillation. The vapor pressure of the monovalent isocyanate a in the description that a solvent is used in the step of removing the monovalent isocyanate a by distillation, and that the vapor pressure of the solvent is lower than that of the monovalent isocyanate a and higher than that of carbodiimide A, refers to the vapor pressure of the pure substance of the monovalent isocyanate a at the reaction temperature in the step of removing the monovalent isocyanate a by distillation. The vapor pressure of the solvent, when the solvent is a pure substance, refers to the vapor pressure of the pure substance of the solvent at the reaction temperature in the step of removing the monovalent isocyanate a by distillation. On the other hand, when the solvent is a mixture of two or more pure substances, it represents the vapor pressure of the mixture of solvents at the reaction temperature during the process of removing monovalent isocyanate a by distillation.The vapor pressure of carbodiimide A refers to the vapor pressure of the pure substance of carbodiimide A at the reaction temperature in the step of removing monovalent isocyanate a by distillation.

[0137] <Method for measuring vapor pressure> The method for measuring vapor pressure is not particularly limited, and vapor pressure can be determined by the static method or the dynamic method, as described in "Temperature, Heat, and Pressure," 5th Edition, Experimental Chemistry Lectures, Vol. 6, Maruzen, pp. 331-364. [Example]

[0138] The present invention will be explained in more detail below by way of specific examples, but the present invention is not limited to the following examples in any way as long as the gist of the invention is not exceeded.

[0139] <Methods for measuring physical properties> [Physical Properties 1] (Amount of carbodiimide functional group) Quantitation was based on the peaks at 130 to 142 ppm derived from the carbodiimide functional group in 13C-NMR measurement.

[0140] [Physical Properties 2] (Amount of monovalent carbodiimide remaining in the prepolymer manufacturing process) After the prepolymer production process, the amount of the residual liquid in the stirring tank was determined by LC analysis.

[0141] [Physical Properties 3] (NCN yield) The NCN yield was calculated from the amount of carbodiimide functional groups in the mixture containing the polyvalent isocyanate and carbodiimide A: α, and the amount of carbodiimide functional groups in the polyvalent carbodiimide B: β, based on the following formula. NCN yield = β / α

[0142] [Physical Properties 4] (Response rate) The reaction rate was calculated based on the following formula using γ, the amount of monovalent isocyanate a when it is assumed that a stoichiometric reaction has progressed from a mixture containing polyvalent isocyanate and carbodiimide A, and ε, the amount of monovalent isocyanate a extracted during the synthesis of polyvalent carbodiimide B, including the prepolymer production process. Response rate = ε / gamma ×100

[0143] [Reference example 1] The actual vapor pressure measurement method and results are shown below. The vapor pressure of each substance at 160°C and 190°C was measured using the static method. Specifically, each substance was sealed in a vacuum-sealed device, and the equilibrium vapor pressure at 160°C and 190°C was measured using a pressure gauge.

[0144] As a result, the vapor pressure of dicyclohexylcarbodiimide at 160°C was 4 kPa. On the other hand, the vapor pressure at 190°C was 11 kPa. The vapor pressure of cyclohexyl isocyanate at 160°C was 62 kPa. On the other hand, the vapor pressure at 190°C was 120 kPa. The vapor pressure of xylene at 160°C was 170 kPa. On the other hand, the vapor pressure at 190°C was 330 kPa. The vapor pressure of 1,2,3,4-tetrahydronaphthalene at 160°C was 30 kPa. On the other hand, the vapor pressure at 190°C was 65 kPa. The vapor pressure of butyl glycol acetate (=ethylene glycol monobutyl ether acetate) at 160°C was 45 kPa. On the other hand, the vapor pressure at 190°C was 90 kPa. The vapor pressure of N-methyl-2-pyrrolidone at 160°C was 35 kPa, while the vapor pressure at 190°C was 73 kPa. The vapor pressure of benzyltoluene at 160°C was 2 kPa, while the vapor pressure at 190°C was 7 kPa.

[0145] Meanwhile, the reaction product of cyclohexyl isocyanate and polyethylene glycol monomethyl ether (number average molecular weight 550), the reaction product of cyclohexyl isocyanate and 1-dodecylamine, and the reaction product of equivalent amounts of cyclohexyl isocyanate and 1-dodecanethiol were obtained, and the vapor pressures of each were measured at 160°C and 190°C. The vapor pressures of all of these products were less than 1 kPa. Meanwhile, the vapor pressures of 4,4'-methylenebis(cyclohexyl isocyanate) at 160°C and 190°C were both less than 1 kPa. The vapor pressure of tetramethylxylylene diisocyanate at 160°C was 2 kPa, and the vapor pressure at 190°C was 7 kPa. The vapor pressure of isophorone diisocyanate at 160°C was 2 kPa, and the vapor pressure at 190°C was 7 kPa. The vapor pressure of 1,6-hexamethylene diisocyanate was 7 kPa at 160° C. and 20 kPa at 190° C. The vapor pressure of 4,4'-diphenylmethane diisocyanate at both 160° C. and 190° C. was less than 1 kPa.

[0146] Since the vapor pressure of cyclohexyl isocyanate is lower than that of the above-mentioned diisocyanates, it is estimated that the monovalent isocyanate b obtained by reacting the above-mentioned diisocyanate with polyethylene glycol monomethyl ether (number average molecular weight 550), the monovalent isocyanate b obtained by reacting the above-mentioned diisocyanate with 1-dodecylamine, and the monovalent isocyanate b obtained by reacting the above-mentioned diisocyanate with 1-dodecanethiol all have vapor pressures of less than 1 kPa at 160°C and 190°C.

[0147] <Synthesis of polyvalent carbodiimide B> [Example 1] 500.00 g (1.906 mol) of dicyclohexylmethane-4,4'-diisocyanate and 199.11 g (0.965 mol) of N,N'-dicyclohexylcarbodiimide were placed in a 2LSUS agitation vessel equipped with a pressure reducing device at the end of condensation tube 1 (the condensate from condensation tube 1 enters the 2LSUS agitation vessel) and condensation tube 2 (the condensate from condensation tube 2 does not enter the 2LSUS agitation vessel but is collected as the TOP liquid) (NCO / NCN = 3.950). The 2LSUS agitation vessel was then heated to 160 °C using a heat transfer medium, after which the pressure inside the agitation vessel was reduced to 15.0 kPa absolute, and the resulting cyclohexyl isocyanate was collected from condensation tube 2 for 1 hour (prepolymer production process). The weight of dicyclohexyl isocyanate recovered at this time was 164.08 g (1.311 mol). Furthermore, when the dicyclohexylcarbodiimide contained in the liquid in the stirring vessel was quantified, it was found to contain 18.52 g (0.090 mol) of dicyclohexylcarbodiimide, a decrease of 9.3 mol% of the dicyclohexylcarbodiimide charged. Next, the internal temperature of the 2LSUS stirring vessel was raised to 190°C, and then the pressure inside the stirring vessel was reduced to 1 kPa absolute, and the resulting cyclohexyl isocyanate was collected from condenser tube 2 for 2 hours (polyvalent carbodiimide B production process).

[0148] The total weight of the recovered cyclohexyl isocyanate and the cyclohexyl isocyanate in the prepolymer production process was 236.08 g (1.886 mol), and the reaction rate was calculated to be 97.7%. The NCN yield was calculated from the concentration of carbodiimide functional groups in the 2LSUS stirring tank, and was found to be 91.7%.

[0149] [Examples 2 to 76] In Examples 2 to 76, polycarbodiimide B was produced in the same manner as in Example 1, except for the conditions shown in the table below. In Examples 67 to 76, a solvent was added to a 2LSUS stirring tank before heating to 160°C.

[0150] In the following table, the abbreviations represent the following compounds.

[0151] hMDI: 4,4'-methylenebis(cyclohexyl isocyanate) TMXDI: Tetramethylxylylene diisocyanate IPDI: Isophorone diisocyanate HDI: 1,6-hexamethylene diisocyanate MDI: 4,4'-diphenylmethane diisocyanate DCC: dicyclohexylcarbodiimide Xylene: Xylene THN: 1,2,3,4-tetrahydronaphthalene BGA: Butyl glycol acetate NMP: N-methyl-2-pyrrolidone BT: Benzyltoluene M550: Polyethylene glycol monomethyl ether (number average molecular weight 550) DA: 1-dodecylamine DT: 1-dodecanethiol

[0152] [Table 1]

[0153] [Table 2]

[0154] [Table 3]

[0155] [Table 4]

[0156] [Table 5]

[0157] [Table 6]

[0158] [Table 7]

[0159] [Table 8]

[0160] [Table 9]

[0161] <Synthesis of polyvalent carbodiimide B> [Example 77] A 2LSUS agitation vessel equipped with a pressure reducing device at the end of condenser tube 1 (the condensate from condenser tube 1 enters the 2LSUS agitation vessel) and condenser tube 2 (the condensate from condenser tube 2 does not enter the 2LSUS agitation vessel but is collected as the TOP liquid) was charged with 500.00 g (1.906 mol) of dicyclohexylmethane-4,4'-diisocyanate and 349.54 g (1.694 mol) of dicyclohexylcarbodiimide (NCO / NCN = 2.250). The 2LSUS agitation vessel was then heated to 160 °C using a heat transfer medium. 232.94 g (0.42 mol) of polyethylene glycol monomethyl ether (number average molecular weight 550) was then added, and the agitation vessel was depressurized to 15.0 kPa absolute pressure. The resulting cyclohexyl isocyanate was collected from condenser tube 2 for 1 h (prepolymer production process). The weight of cyclohexyl isocyanate recovered at this time was 295.85 g (2.364 mol). Furthermore, when the dicyclohexylcarbodiimide contained in the liquid in the stirring tank was quantified, it was found to contain 30.64 g (0.148 mol) of dicyclohexylcarbodiimide, a decrease of 8.8 mol% of the dicyclohexylcarbodiimide charged. Next, the internal temperature of the 2LSUS stirring tank was raised to 190°C, and then the pressure inside the stirring tank was reduced to 1 kPa absolute, and the cyclohexyl isocyanate produced was collected from condenser tube 2 for 2 hours (polyvalent carbodiimide B production process).

[0162] The total weight of the recovered cyclohexyl isocyanate and the cyclohexyl isocyanate in the prepolymer production process was 420.27 g (3.358 mol), and the reaction rate was calculated to be 99.1%. The NCN yield was calculated from the concentration of carbodiimide functional groups in the 2LSUS stirring tank, and was found to be 96.7%.

[0163] [Examples 78 to 91] In Examples 78 to 91, polycarbodiimide B was produced in the same manner as in Example 77, except that the procedures were as shown in the table below.

[0164] [Table 10]

[0165] [Table 11]

[0166] [Table 12]

[0167] [Table 13]

[0168] <Synthesis of polyvalent carbodiimide B> [Example 92] A 2LSUS agitator equipped with a pressure reducing device at the end of condenser tube 1 (the condensate from condenser tube 1 enters the 2LSUS agitator) and condenser tube 2 (the condensate from condenser tube 2 does not enter the 2LSUS agitator but is collected as the TOP liquid) was charged with 500.00 g (1.906 mol) of dicyclohexylmethane-4,4'-diisocyanate and 349.54 g (1.694 mol) of dicyclohexylcarbodiimide (NCO / NCN = 2.250). The 2LSUS agitator was then heated to 160 °C using a heat transfer medium, after which the pressure inside the agitator was reduced to 15.0 kPa absolute. The resulting cyclohexyl isocyanate was collected from condenser tube 2 over a period of 1 hour (prepolymer production process). The weight of the cyclohexyl isocyanate collected was 294.33 g (2.351 mol). Furthermore, the amount of dicyclohexylcarbodiimide contained in the liquid in the stirring tank was quantified, and it was found to contain 31.38 g (0.152 mol) of dicyclohexylcarbodiimide, which was reduced to 9.0 mol% of the charged dicyclohexylcarbodiimide. Next, the internal temperature of the 2LSUS stirring tank was raised to 190°C, and then the pressure inside the stirring tank was reduced to 1 kPa absolute, and the cyclohexyl isocyanate produced was collected from condenser tube 2 for 2 hours (polyvalent carbodiimide B production process).

[0169] The total weight of the recovered cyclohexyl isocyanate and the cyclohexyl isocyanate from the prepolymer production process was 420.24 g (3.357 mol), giving a reaction rate of 99.1%. Then, 232.94 g (0.42 mol) of polyethylene glycol monomethyl ether (number average molecular weight 550) was added and the reaction was allowed to proceed for 1 hour. The NCN yield was calculated from the concentration of carbodiimide functional groups in the 2LSUS stirring vessel, giving a NCN yield of 97.4%.

[0170] [Examples 93 to 106] In Examples 93 to 106, polycarbodiimide B was produced in the same manner as in Example 92, except that the procedures were as shown in the table below.

[0171] [Table 14]

[0172] [Table 15]

[0173] [Table 16]

[0174] [Table 17]

[0175] [Comparative Example 1] Hexamethylene diisocyanate: 313.00 g (1.861 mol) and N,N'-dicyclohexylcarbodiimide: 206.33 g (1.861 mol) (NCO / NCN = 2.000) were placed in a 2LSUS agitator equipped with a pressure reducing device at the end of condenser tube 1 (the condensate from condenser tube 1 enters the 2LSUS agitator) and condenser tube 2 (the condensate from condenser tube 2 does not enter the 2LSUS agitator but is collected as the TOP liquid). The 2LSUS agitator was then heated to 90 °C using a heat transfer medium, after which the pressure inside the agitator was reduced to 26.7 Pa absolute. The resulting cyclohexyl isocyanate was collected from condenser tube 2 over a period of 5 h (prepolymer production process). The weight of the cyclohexyl isocyanate collected was 184.00 g (1.470 mol). The amount of dicyclohexylcarbodiimide in the stirred tank was quantified, revealing 120.51 g (0.584 mol) of dicyclohexylcarbodiimide, a decrease of 31.4 mol% of the dicyclohexylcarbodiimide charged. Next, 200.00 g of dicyclohexylcarbodiimide was added to the 2LSUS stirred tank, and the internal temperature was raised to 210°C. The resulting cyclohexyl isocyanate was continuously withdrawn along with the dicyclohexylcarbodiimide, resulting in the withdrawal of 232.00 g (1.853 mol) of cyclohexyl isocyanate and 99.00 g (0.480 mol) of dicyclohexylcarbodiimide. The reaction rate was determined to be 89.3% from the amount of hexamethylene diisocyanate charged and the amount of cyclohexyl isocyanate withdrawn. Furthermore, the NCN yield was calculated from the concentration of carbodiimide functional groups contained in the 2LSUS stirring vessel, and was found to be 75.6%.

[0176] The polycarbodiimides B obtained in Examples 1 to 106 had an NCN yield of 80.0% or more, and produced little by-product, which was excellent. Among them, Examples 1 to 8 and Examples 34 to 41, which used a polyisocyanate in which an isocyanate functional group was bonded to an aliphatic secondary carbon, and Examples 9 to 16 and Examples 42 to 49, which used a polyisocyanate in which an isocyanate functional group was bonded to an aliphatic tertiary carbon, had an NCN yield of 90% or more, which was even better.

[0177] Furthermore, in Examples 68 to 70, in which a polyisocyanate in which an isocyanate functional group is bonded to an aliphatic primary carbon was used as the polyisocyanate and a solvent having a boiling point intermediate between that of the polyisocyanate and the monoisocyanate a was used as the solvent, the NCN yield was 90% or more, which was even better.

[0178] Furthermore, in Examples 77 to 79, in which a polyisocyanate in which an isocyanate functional group is bonded to an aliphatic secondary carbon was used as the polyisocyanate and the mixture of the polyisocyanate and carbodiimide A contained a monoisocyanate b having a vapor pressure lower than the vapor pressure of the monoisocyanate a derived from carbodiimide A, the NCN yield was 93.9% or more, which was even better.

[0179] Furthermore, in Examples 80 to 82, in which a polyisocyanate in which an isocyanate functional group is bonded to an aliphatic tertiary carbon was used as the polyisocyanate and the mixture of the polyisocyanate and carbodiimide A contained monoisocyanate b having a vapor pressure lower than the vapor pressure of monoisocyanate a derived from carbodiimide A, the NCN yield was 94.2% or more, which was even better.

[0180] Furthermore, Examples 92 to 94, which used a polyisocyanate in which an isocyanate functional group was bonded to an aliphatic secondary carbon, and included a step of removing monoisocyanate a derived from carbodiimide A by distillation, followed by a step of reacting the remaining isocyanate functional group with a compound capable of reacting with the isocyanate functional group, had an even better NCN yield of 94.1% or more.

[0181] Furthermore, Examples 95 to 97, which used a polyisocyanate in which an isocyanate functional group was bonded to an aliphatic tertiary carbon, and included a step of removing monoisocyanate a derived from carbodiimide A by distillation, followed by a step of reacting the remaining isocyanate functional group with a compound capable of reacting with the isocyanate functional group, had an even better NCN yield of 94.3% or more.

[0182] On the other hand, in Comparative Example 1, in which a polyvalent isocyanate in which an isocyanate functional group is bonded to an aliphatic primary carbon was used and reacted under the condition of a molar ratio of isocyanate functional groups NCO / NCN = 2.000, an excess amount of monovalent carbodiimide was added, and monovalent isocyanate a was extracted simultaneously with the monovalent carbodiimide, the NCN yield was 75.6%, which was poor.

[0183] [Reference example 2] In Example 92, the amount of cyclohexyl isocyanate in the reaction product after distillation was measured by LC analysis. Specifically, 10 parts by mass of aniline was added to 1 part by mass of the reaction product after distillation, and the mixture was allowed to react at 25°C for 30 minutes. The resulting solution was then diluted with 1,000 parts by mass of acetic acid. Quantitation was performed using a Shimadzu LC-10AT LC system, two GL Science Inertsil-ODS reverse-phase columns connected in series, and a photodiode array detector (PDA). The developing solvent was a mixture of 0.1 wt% aqueous phosphoric acid (liquid A) and acetonitrile (liquid B) in a volume ratio of 50:30, and the volume ratio was changed to 10:90 over 100 minutes. The solvent flow rate was 2 mL / min and the column temperature was 40°C. The peak was acquired at 210 nm.

[0184] As a result, the amount of cyclohexyl isocyanate contained in the reaction product after distillation was determined to be 15 mmol. On the other hand, when the amount of cyclohexyl isocyanate contained in the reaction product after reaction with a compound that can react with isocyanate was determined using the same method, no cyclohexyl isocyanate was detected.

[0185] The amount of the reaction product of cyclohexyl isocyanate and polyethylene glycol monomethyl ether (number-average molecular weight 550) in the reaction product after reaction with an isocyanate-reactive compound was also measured. Specifically, quantification was performed using a Shimadzu LC-10AT LC system, three Tosoh TSKgel SuperH1000 columns connected in series, and a photodiode array detector (PDA) under the following conditions: THF as the developing solvent, a solvent flow rate of 1 mL / min, and a column temperature of 40 °C. Because the reaction product of cyclohexyl isocyanate and polyethylene glycol monomethyl ether (number-average molecular weight 550) has a uniform molecular weight distribution, the peak of the reaction product obtained by reacting cyclohexyl isocyanate with polyethylene glycol monomethyl ether (number-average molecular weight 550) in advance so that the isocyanate functional group and hydroxyl group were equivalent was used as the standard. The peak was acquired at 210 nm.

[0186] As a result, the amount of the reaction product of cyclohexyl isocyanate and polyethylene glycol monomethyl ether (number average molecular weight 550) contained in the reaction product after reaction with a compound reactive with isocyanate was determined to be 30 mmol.

[0187] The amount of cyclohexyl isocyanate contained in the reaction product after the distillation operation was 15 mmol, whereas the amount of cyclohexyl isocyanate contained in the reaction product after the reaction with a compound that can react with isocyanate was not detected. Therefore, it is believed that free cyclohexyl isocyanate reacted with polyethylene glycol monomethyl ether (number average molecular weight 550).

[0188] Furthermore, the amount of the reaction product of cyclohexyl isocyanate and polyethylene glycol monomethyl ether contained in the reaction product after the reaction with the compound reactive with isocyanate was 30 mmol, which is larger than the amount of cyclohexyl isocyanate contained in the reaction product after the distillation operation (15 mmol). Therefore, it is considered that the uretonimine functional group obtained by the reaction of cyclohexyl isocyanate with the carbodiimide functional group reacted with polyethylene glycol monomethyl ether (number average molecular weight 550). [Industrial Applicability]

[0189] According to the method for producing a polycarbodiimide of the present embodiment, it is possible to provide a method for producing a polycarbodiimide with a controlled structure, while reducing the by-products produced in the method for producing a polycarbodiimide in which a residue bonded to a carbodiimide functional group is exchanged for a residue bonded to an isocyanate functional group.

Claims

1. forming a uretonimine from a mixture containing a polyisocyanate and carbodiimide A; decomposing the uretonimine; and removing the monovalent isocyanate a derived from the carbodiimide A by distillation, The carbodiimide A is either one or both of a monovalent carbodiimide and a polyvalent carbodiimide, the molar ratio of isocyanate functional groups to carbodiimide functional groups in the mixture containing carbodiimide A is 1<NCO / NCN<4 (excluding NCO / NCN=2.000), the reaction rate in the step of removing the monovalent isocyanate a by distillation is 80% or more, The reaction rate is a value calculated based on the following formula (5) from the theoretical amount of substance Mt of monovalent isocyanate a extracted as vapor and the amount of substance Mr of monovalent isocyanate a actually extracted as vapor, assuming that the reaction has occurred quantitatively based on the amount of substance of carbodiimide functional groups and the amount of substance of isocyanate functional groups contained in the charged composition: Reaction rate=Mr / Mt×100(5)

2. The method for producing a polyvalent carbodiimide B according to claim 1, wherein the polyvalent isocyanate is represented by the following general formula (1): 【Chemistry 1】 (In the formula, R １ is an organic group containing an integer number of carbon atoms ranging from 1 to 85, and n1 is an integer from 2 to 12.

3. The method for producing a polyvalent carbodiimide B according to claim 1 or 2, wherein the carbodiimide A is represented by the following general formula (2): 【Chemistry 2】 (In the formula, R ２ , R ４ are each independently a monovalent organic group containing an integer number of carbon atoms ranging from 1 to 85, and R ３ is a divalent or higher organic group containing an integer number of carbon atoms in the range of 1 to 85, which may have a branched structure. n2 is an integer of 1 or more. When n2 is 2 or more, multiple R ３ may have different structures.)

4. The method for producing a polyvalent carbodiimide B according to claim 1 or 2, wherein the monovalent isocyanate a is represented by the following general formula (3): 【Transformation 3】 (In the formula, R ５ is an organic group containing an integer number of carbon atoms ranging from 1 to 85.

5. 3. The method for producing polyvalent carbodiimide B according to claim 1 or 2, wherein the isocyanate functional group in the polyvalent isocyanate is bonded to any one of an aliphatic primary carbon, an aliphatic secondary carbon, and an aliphatic tertiary carbon.

6. 3. The method for producing a polyvalent carbodiimide B according to claim 1 or 2, wherein the carbodiimide functional group in the carbodiimide A is bonded to any one of an aliphatic primary carbon, an aliphatic secondary carbon, and an aliphatic tertiary carbon.

7. A step of obtaining a prepolymer A represented by the following general formula (4) by reacting a polyisocyanate with a monovalent carbodiimide; a step of reacting the prepolymer A under either or both of a higher temperature condition and a reduced pressure condition than in the step of obtaining the prepolymer A, 【Chemistry 4】 (In the formula, R ６ is an organic group derived from a monovalent carbodiimide, and R ７ is an organic group derived from a polyvalent isocyanate, n3 and n4 are each independently an integer, n3 is 1 or more, n3 + n4 is equal to the isocyanate valence of the polyvalent isocyanate, A is an organic group that bonds to the organic group derived from the polyvalent isocyanate, and when n4 is 2 or more, the multiple A's may be different from each other.

8. 8. The method for producing a polyvalent carbodiimide B according to claim 7, wherein in the step of obtaining the prepolymer A, the reaction is carried out until the content of the monovalent carbodiimide becomes less than 15% based on the amount of the charged substance.

9. The method for producing a polyvalent carbodiimide B according to claim 7 or 8, wherein in the step of reacting the prepolymer A, the reaction is carried out under conditions equal to or lower than the vapor pressure of the monovalent carbodiimide.

10. A method for producing a polyvalent carbodiimide B, comprising the steps of: forming a uretonimine from a mixture containing a polyvalent isocyanate and a carbodiimide A; decomposing the uretonimine; and removing a monovalent isocyanate a derived from the carbodiimide A by a distillation operation, wherein the carbodiimide A is one or both of a monovalent carbodiimide and a polyvalent carbodiimide; the mixture of the polyvalent isocyanate and the carbodiimide A contains a monovalent isocyanate b, and the monovalent isocyanate b has a vapor pressure lower than the vapor pressure of the monovalent isocyanate a derived from the carbodiimide A.

11. The method for producing polyvalent carbodiimide B according to claim 10, wherein the monovalent isocyanate b is a compound represented by the following general formula (IV-1) and / or the following general formula (IV-2): 【Transformation 5】 (In general formula (IV-1), R ８ is an organic group having 1 to 12 carbon atoms. 【Transformation 6】 (In general formula (IV-2), R ９ , R １０ represents an organic group, and Q represents a structure represented by the following general formulas (IV-2-1) to (IV-2-5). 【Transformation 7】 In general formulas (IV-2-1) to (IV-2-5), an asterisk represents a bonding site with a functional group.

12. The monovalent isocyanate b is a structure represented by the general formula (IV-2), and R １０ The method for producing polyvalent carbodiimide B according to claim 10 or 11, wherein: 【Transformation 8】

13. The monovalent isocyanate b is a structure represented by the general formula (IV-2), and R ９ The method for producing polyvalent carbodiimide B according to claim 10 or 11, wherein has a polyalkylene oxide structure.

14. The method comprises the steps of: forming a uretonimine from a mixture containing a polyisocyanate and a carbodiimide A; decomposing the uretonimine; and removing the monoisocyanate a derived from the carbodiimide A by distillation; The carbodiimide A is either one or both of a monovalent carbodiimide and a polyvalent carbodiimide, and the method for producing a polyvalent carbodiimide B includes a step of removing the monovalent isocyanate a by distillation, and then reacting the remaining isocyanate functional group with a compound capable of reacting with the isocyanate functional group.

15. The method comprises the steps of: forming a uretonimine from a mixture containing a polyisocyanate and a carbodiimide A; decomposing the uretonimine; and removing the monoisocyanate a derived from the carbodiimide A by distillation; The carbodiimide A is either one or both of a monovalent carbodiimide and a polyvalent carbodiimide, and the method for producing a polyvalent carbodiimide B includes a step of removing the monovalent isocyanate a by distillation, and then reacting the remaining uretonimine with a compound capable of reacting with uretonimine.

16. 3. The method for producing polyvalent carbodiimide B according to claim 1, wherein a solvent is used in the step of removing said monovalent isocyanate a by distillation.

17. The method for producing a polyvalent carbodiimide B according to claim 16, wherein the vapor pressure of the solvent is lower than the vapor pressure of the monovalent isocyanate a and higher than the vapor pressure of the carbodiimide A.

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