Method for producing blocked isocyanate composition

Abstract

To provide a method for producing a blocked isocyanate composition with excellent continuous operability.SOLUTION: A method for producing a blocked isocyanate composition comprises: a first step of reacting a primary amine compound, a carbonate derivative represented by one or both of the specified general formulas (II) and (III), and a blocking agent, through heat treatment so as to obtain a first blocked isocyanate composition; and a second step of converting the carbonate derivative represented by one or both of the specified general formulas (II) and (III) contained in the first blocked isocyanate composition into a structure represented by the general formula (I) in the figure so as to obtain a second blocked isocyanate composition.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a blocked isocyanate composition. [Background technology]

[0002] Isocyanates are widely used as raw materials for manufacturing polyurethane foams, paints, adhesives, etc. The main industrial method for manufacturing isocyanates is the reaction of an amine compound with phosgene (phosgene process), and almost all of the world's production volume is produced by the phosgene process. However, the phosgene process has many problems related to the raw material phosgene and the by-product hydrogen chloride.

[0003] In view of this background, a method for producing an isocyanate without using phosgene is desired. For example, Patent Document 1 describes a method for producing an isocyanate by reacting a non-aromatic amine with an alkylaryl carbonate to produce a carbamate, and then thermally decomposing the resulting carbamate. Patent Document 2 describes a method for producing a diisocyanate compound by reacting a diamine with dimethyl carbonate in the presence of an alkali catalyst to synthesize a urethane compound, and then thermally decomposing the urethane compound in the presence of a catalyst. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-252846 A [Patent Document 2] Japanese Unexamined Patent Publication No. 64-85956 Summary of the Invention [Problem to be solved by the invention]

[0005] When an isocyanate is produced using a carbonic acid derivative, depending on the type of the carbonic acid derivative, there is a risk that clogging of the reactor and piping will be induced, resulting in a decrease in continuous operability.

[0006] The present invention has been made in consideration of the above circumstances, and provides a method for producing a blocked isocyanate composition which is excellent in continuous operability. [Means for solving the problem]

[0007] That is, the present invention includes the following aspects. [1] A method for producing a blocked isocyanate composition, comprising: a first step of reacting a primary amine compound, a carbonic acid derivative represented by either or both of the following general formulas (II) and (III), and a blocking agent by heat treatment to obtain a first blocked isocyanate composition; and a second step of converting the carbonic acid derivative represented by either or both of the following general formulas (II) and (III) contained in the first blocked isocyanate composition to a structure represented by the following general formula (I) to obtain a second blocked isocyanate composition. [ka] (In general formula (I), R 1 and R 2 R is each independently a monovalent organic group. 1 and R 2 may each independently form a ring structure via a carbon-carbon bond, a carbon-oxygen-carbon bond, or a carbon-nitrogen-carbon bond. 3 is a hydrocarbon group having an aliphatic hydrocarbon group or an aromatic group. [ka] (In general formula (II), X 1 is a monovalent organic group. [ka] (In general formula (III), X 2 and X 3 are each independently hydrogen or a monovalent organic group. [2] The method for producing a blocked isocyanate composition according to [1], wherein the blocking agent in the first step contains one or more compounds selected from the group consisting of a hydroxy compound, an amine compound, and ammonia. [3] The method for producing a blocked isocyanate composition according to [1] or [2], wherein the primary amine compound in the first step is an amine compound represented by the following general formula (IV): [ka] (In general formula (IV), R 41 is an organic group having a valence of n41, where n41 is an integer of 1 or more and 12 or less. [4] The method for producing a blocked isocyanate composition according to any one of [1] to [3], wherein the blocking agent in the first step is an aromatic hydroxy compound represented by the following general formula (V): [ka] (In general formula (V), ring A 51 R is an aromatic hydrocarbon ring having 6 to 20 carbon atoms. 51 is a hydrogen atom, a halogen atom, a carboxy group, an alkyl group having from 1 to 20 carbon atoms, an alkoxy group having from 1 to 20 carbon atoms, an alkyloxycarbonyl group having from 1 to 20 carbon atoms, an alkylcarbonyloxy group having from 1 to 20 carbon atoms, an aryl group having from 6 to 20 carbon atoms, an aryloxy group having from 6 to 20 carbon atoms, an aralkyl group having from 7 to 20 carbon atoms, or an aralkyloxy group having from 7 to 20 carbon atoms. 51 is ring A 51 may be bonded to form a ring structure. n51 is an integer of 1 or more and 10 or less. [5] The method for producing a blocked isocyanate composition according to any one of [1] to [4], wherein the blocking agent in the first step is an aliphatic hydroxy compound represented by the following general formula (VI): [ka] (In general formula (VI), R 61is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 24 carbon atoms, which may have an ether group, a carbonyl group, or an ester group. [6] The method for producing a blocked isocyanate composition according to any one of [1] to [5], wherein the blocking agent in the first step is a secondary amine compound represented by the following general formula (VII): [ka] (In general formula (VII), R 71 and R 72 R is each independently a monovalent organic group. 71 and R 72 may be bonded to each other to form a ring structure via a carbon-carbon bond, a carbon-oxygen-carbon bond, or a carbon-nitrogen-carbon bond. [7] The method for producing a blocked isocyanate composition according to any one of [1] to [6], wherein the second blocked isocyanate composition contains one or more compounds selected from the group consisting of hydroxy compounds and one or more compounds selected from the group consisting of secondary amine compounds. [8] The method for producing a blocked isocyanate composition according to any one of [1] to [7], wherein the second blocked isocyanate composition contains a strong base catalyst which forms a salt with one or more compounds selected from the group consisting of hydroxy compounds, in an amount of 1 ppb by mass or more relative to the carbonic acid derivative represented by either one or both of the general formulas (II) and (III). Effect of the Invention

[0008] According to the method for producing a blocked isocyanate composition of the above embodiment, a method for producing a blocked isocyanate composition having excellent continuous operability can be provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 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.

[0010] In this specification, the term "active hydrogen" refers to a hydrogen atom bonded to an oxygen atom, a sulfur atom, or a nitrogen atom, and a hydrogen atom of an active methylene group, such as a hydrogen atom contained in an atomic group such as -OH group, -C(=O)OH group, -SH group, -NH2 group, -NH- group, -C(=O)-C(-H)2-C(=O)- group, etc.

[0011] <Method for producing blocked isocyanate composition> The method for producing a blocked isocyanate composition according to the present embodiment includes a first step of reacting a primary amine compound, a carbonic acid derivative represented by either or both of the following general formulas (II) and (III), and a blocking agent by heat treatment to obtain a first blocked isocyanate composition, and a second step of converting the carbonic acid derivative represented by either or both of the following general formulas (II) and (III) contained in the first blocked isocyanate composition to a structure represented by the following general formula (I), to obtain a second blocked isocyanate composition.

[0012] [ka]

[0013] (In general formula (I), R 1 and R 2 R is each independently a monovalent organic group. 1 and R 2 may each independently form a ring structure via a carbon-carbon bond, a carbon-oxygen-carbon bond, or a carbon-nitrogen-carbon bond. 3 is a hydrocarbon group having an aliphatic hydrocarbon group or an aromatic group.

[0014] [ka]

[0015] (In general formula (II), X 1 is a monovalent organic group.

[0016] [ka]

[0017] (In general formula (III), X 2 and X 3 are each independently hydrogen or a monovalent organic group.

[0018] In the method for producing a blocked isocyanate composition according to the present embodiment, a carbonic acid derivative represented by either one or both of general formulas (II) and (III) is converted to a structure represented by general formula (I) in the second step. The carbonic acid derivative represented by either one or both of general formulas (II) and (III) is a component derived from isocyanic acid, and is a cause of adhesion of piping. By converting such a carbonic acid derivative to a structure represented by general formula (I), which is a harmless and stable component, in the second step, a method for producing a blocked isocyanate composition with excellent continuous operability can be provided.

[0019] Each step will be described below.

[0020] ≪1st process≫ In the first step, a primary amine compound, a carbonic acid derivative represented by either one or both of the above general formulas (II) and (III), and a blocking agent are reacted by heat treatment to obtain a first blocked isocyanate composition.

[0021] In the first step, the ratio of the amounts of the primary amine compound and the blocking agent added can be selected arbitrarily. When expressed as a molar ratio, the ratio of the molar amount of amino groups in the primary amine compound to the molar amount of active hydrogen in the blocking agent is generally 1:1, or the molar amount of active hydrogen in the blocking agent is greater than the molar amount of amino groups in the primary amine compound. When expressed as a mass ratio, it is preferable that the blocking agent is present in an amount that is in excess of the primary amine compound. For example, the mass ratio of the primary amine compound to the blocking agent added can be 1:1 to 1:999.

[0022] In the first step, the ratio of the amounts of the primary amine compound and the carbonic acid derivative added can be selected arbitrarily. When expressed as a molar ratio, the ratio of the molar amount of the amino group of the primary amine compound to the molar amount of the carbonyl group of the carbonic acid derivative is generally within a range of 1:0.5 to 1:20. When expressed as a mass ratio, for example, the amount of the primary amine compound and the carbonic acid derivative added can be set to a mass ratio of 1:0.01 to 1:99.

[0023] The reaction temperature in the first step is not particularly limited and is appropriately selected depending on the reaction rate of the primary amine compound, the carbonic acid derivative, and the blocking agent, and the degree of thermal denaturation and coloration. From the viewpoint of suppressing the denaturation of the blocked isocyanate compound, the reaction temperature is preferably 350° C. or less, more preferably 300° C. or less, and even more preferably 260° C. or less. On the other hand, when the reaction temperature is low, it becomes necessary to set the temperature of the condenser at a low temperature, and new equipment may be required, so from that viewpoint, the reaction temperature is preferably 50° C. or more, more preferably 80° C. or more, and even more preferably 100° C. or more.

[0024] The reaction pressure in the first step varies depending on the type of compound used and the reaction temperature, but may be reduced pressure, normal pressure, or increased pressure. Generally, the absolute pressure is 20 Pa or more and 2×10 7 The temperature is set in the range of Pa or less.

[0025] The first step may be carried out in the presence of oxygen. When the first step is carried out in the presence of oxygen, the amount of oxygen present in the production equipment of the blocked isocyanate compound is preferably reduced, since the blocked isocyanate compound is thermally denatured and colored. On the other hand, in the case of a large-scale production facility, in order to reduce the amount of oxygen present in the production equipment of the blocked isocyanate compound, it is necessary to reduce the leakage of air into the production facility, which makes the design standard of the facility stricter and causes an increase in the facility cost. From this viewpoint, it is preferable to control the oxygen concentration in the gas supplied to the first step under high conditions, preferably at more than 0% by volume, more preferably at more than 0.0001% by volume, and even more preferably at more than 0.001% by volume.

[0026] In the first step, any solvent may be used in any ratio. As the solvent, an inert solvent that does not have reactivity with a primary amine compound, a carbonic acid derivative, a blocking agent, a blocked isocyanate compound, etc. is preferable. As such a solvent, an ester solvent, an ether solvent, a phosphoric acid ester solvent, a hydrocarbon solvent, an aromatic hydrocarbon solvent, or a carbonic acid derivative solvent is preferable.

[0027] In the first step, the reaction mixture may contain any metal in any ratio. The form of the metal may be a complex or a solid. The metal reduces the thermal decomposition temperature of the blocked isocyanate compound and promotes the reaction between the primary amine compound and the carbonic acid derivative, but may cause thermal denaturation, deterioration, and coloration. The content of the metal is preferably less than 10 mass%, more preferably less than 1 mass%, and even more preferably less than 0.1 mass ppm, relative to the mass of the blocked isocyanate compound.

[0028] In the first step, the reaction mixture may contain an organic acid, an inorganic acid, an organic base, or an inorganic base. These acids and bases act as catalysts in the thermal decomposition of the blocked isocyanate, reducing the temperature required for the thermal decomposition and promoting the reaction between the primary amine compound and the carbonic acid derivative. On the other hand, these acids and bases also act as catalysts for side reactions in the thermal decomposition of the blocked isocyanate. From these viewpoints, the content of these organic acids, inorganic acids, organic bases, and inorganic bases is preferably less than 10% by mass, more preferably less than 1% by mass, even more preferably less than 0.1% by mass, and particularly preferably less than 1 ppb by mass, based on the mass of the blocked isocyanate compound.

[0029] In the first step, a blocked isocyanate compound is obtained as a first blocked isocyanate composition containing the blocked isocyanate compound. The blocked isocyanate compound is a compound that can be decomposed into an isocyanate compound and a blocking agent by thermal decomposition.

[0030] The blocked isocyanate composition means a composition containing more than 0 mass % and 100 mass % or less of a blocked isocyanate compound in the composition. The blocked isocyanate composition is not particularly limited except that it contains a blocked isocyanate compound, and may contain a solvent, a blocking agent, an isocyanate, a catalyst, a primary amine compound, etc. in any ratio.

[0031] In view of the above, the blocked isocyanate composition may be used as it is as the blocked isocyanate compound, or the blocked isocyanate compound may be purified from the blocked isocyanate composition and then used.

[0032] The reaction apparatus is not particularly limited, and a known production apparatus for blocked isocyanate can be used. For example, a device in which raw materials and the like are added into a container connected to one or more devices selected from the group consisting of a condensation device and a treatment device, the container is heated to produce a blocked isocyanate compound, and then or simultaneously, steam containing a compound derived from a carbonic acid derivative is introduced into a condensation device or a treatment device to synthesize a blocked isocyanate compound in a batch system, or a device in which raw materials and the like are continuously introduced into a distillation column heated to a predetermined reaction temperature, steam containing a compound derived from a carbonic acid derivative generated simultaneously with the production of a blocked isocyanate compound is separated to continuously obtain a blocked isocyanate compound can be used. It is also possible to partially or completely react a primary amine compound and a carbonic acid derivative in the presence or absence of a blocking agent, and then produce a blocked isocyanate compound from the resulting reaction product.

[0033] The material of the portion of the reaction apparatus that comes into contact with the mixture containing the primary amine compound, the carbonic acid derivative, and the blocking agent, and the blocked isocyanate composition produced by the reaction, may be any known material as long as it does not adversely affect the modification of the primary amine compound, the carbonic acid derivative, the blocking agent, the blocked isocyanate compound, and other components, etc. Specific examples of the material include steel, stainless steel, ceramic, carbon, and materials lined with these materials.

[0034] [Carbonic acid derivatives] In the first step, the carbonic acid derivative used is one or both of the carbonic acid derivatives represented by the above general formulas (II) and (III) (hereinafter, these may be referred to as "carbonic acid derivative (II)" and "carbonic acid derivative (III)", respectively). The carbonic acid derivative (II) and the carbonic acid derivative (III) each contain at least one -C(=O)-NH2 group.

[0035] [Carbonic acid derivatives (II)] Carbonic acid derivative (II) has an -OC(=O)-NH2 group as shown in the above general formula (II). X in the above general formula (II) 1is not particularly limited as long as it is a monovalent organic group, but it is preferable that the carbonic acid derivative (II) is an N-unsubstituted carbamic acid ester. 1 is preferably a substituted or unsubstituted alkyl group, aryl group, or aralkyl group.

[0036] Among them, X 1 X is preferably a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. 1 Examples of the substituent that the alkyl group, aralkyl group or aryl group may have include an alkyl group, an alkoxy group, and the like.

[0037] [Carbonic acid derivatives (III)] Carbonic acid derivative (III) has a >NC(=O)-NH2 group as shown in the above general formula (III). X in the above general formula (III) 2 and X 3 is not particularly limited as long as it is each independently hydrogen or a monovalent organic group, but it is preferable that the carbonic acid derivative (III) is an unsubstituted urea compound, a monosubstituted urea compound, or an N,N-disubstituted urea compound.

[0038] Among them, X 2 and X 3 are preferably each independently hydrogen, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. 2 and X 3 Examples of the substituents on the alkyl group, aryl group or aralkyl group include an alkyl group and an alkoxy group. 2 and X 3 The total number of carbon atoms constituting the group is preferably an integer of 0 or more and 20 or less.

[0039] The carbonic acid derivative (III) may be a biuret compound having at least one unsubstituted NH2 group. In this case, X 2 Or X3 It is preferable that either one of the above is a group represented by the following general formula (III-a).

[0040] R 31 -(R 32 -)NC(=O)- (III-a)

[0041] In the above general formula (III-a), R 31 and R 32 each independently represents a hydrogen atom or a substituted or unsubstituted alkyl group, aralkyl group, or aryl group.

[0042] Among them, R 31 and R 32 R is preferably independently hydrogen, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. 31 and R 32 Examples of the substituents on the alkyl group, aryl group, or aralkyl group include an alkyl group and an alkoxy group. 31 and R 32 The total number of carbon atoms constituting the group is preferably an integer of 0 or more and 20 or less.

[0043] The carbonic acid derivative (III) may be an allophanate compound having an unsubstituted NH group. In this case, X 2 Or X 3 It is preferable that either one of the above is a group represented by the following general formula (III-b).

[0044] R 33 -OC(=O)- (III-b)

[0045] In the above general formula (III-b), R 33 is a substituted or unsubstituted alkyl group, aralkyl group, or aryl group.

[0046] Among them, R 33R is preferably a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. 33 Examples of the substituents on the alkyl group, aryl group, or aralkyl group include an alkyl group and an alkoxy group. 33 The total number of carbon atoms constituting the group is preferably an integer of 1 or more and 20 or less.

[0047] [Primary amine compounds] As the primary amine compound in the first step, an amine compound represented by the following general formula (IV) (hereinafter, sometimes referred to as "primary amine compound (IV)") is preferably used.

[0048] [ka]

[0049] (In general formula (IV), R 41 is an organic group having a valence of n41, where n41 is an integer of 1 or more and 12 or less.

[0050] R 41 R is not particularly limited as long as it is an organic group having a valence of 1 to 12, but is preferably an organic group consisting of carbon and hydrogen atoms (hydrocarbon group) or an organic group consisting of carbon, oxygen and hydrogen atoms, and more preferably an organic group having no active hydrogen. 41 The oxygen atom contained in preferably constitutes an ether group or an ester group.

[0051] R 41 The aliphatic hydrocarbon group in is preferably an alkyl group, an alkylene group, an alkanetriyl group, a cycloalkyl group, a cycloalkylene group or a cycloalkanetriyl group, or a group composed of two or more of these.

[0052] R 41The aromatic hydrocarbon group in is preferably a substituted or unsubstituted group having an aromatic ring with a carbon number of 6 to 13. Examples of the substituent include an alkyl group, an aralkyl group, an aryl group, an alkoxy group, an alkoxycarbonyl group, and an alkylcarbonyloxy group.

[0053] The primary amine compound (IV) includes a monofunctional primary amine compound, a bifunctional primary amine compound, and a polyfunctional primary amine compound.

[0054] In monofunctional primary amine compounds, R 41 Examples of the monovalent organic group include a substituted or unsubstituted alkyl group, a cycloalkyl group, an aralkyl group, and an aryl group.

[0055] In bifunctional primary amine compounds, R 41 Examples of the divalent organic group include a substituted or unsubstituted alkylene group, a cycloalkylene group, an arylene group, an arylene dialkylene group, an alkylenediarylene group, an alkylenedicycloalkylene group, etc. The bifunctional primary amine compound may be a compound having an aminoalkyl group such as isophoronediamine, a compound having an aminocycloalkyl group such as dicyclohexylmethane 4,4'-diamine, a compound having an aminoaryl group such as diphenylmethanediamine, or a compound having a carbonyl group such as lysine alkyl ester.

[0056] In polyfunctional primary amine compounds, R 41 Examples of the polyvalent organic group include a substituted or unsubstituted alkanetriyl group, a cycloalkanetriyl group, an arenetriyl group, etc. The polyfunctional primary amine compound may be a compound having an aminoalkyl group, such as 4-aminomethyl-1,8-octamethylenediamine, or a compound having a carbonyl group, such as lysine aminoalkyl ester.

[0057] [Blocking agent] The blocking agent is a compound having active hydrogen. The blocking agent in the first step preferably contains one or more compounds selected from the group consisting of hydroxy compounds, amine compounds, and ammonia. The hydroxy compounds include one or more compounds selected from the group consisting of aromatic hydroxy compounds and aliphatic hydroxy compounds.

[0058] [Blocking agents that are aromatic hydroxy compounds] Aromatic hydroxy compounds preferred as blocking agents include aromatic hydroxy compounds represented by the following general formula (V).

[0059] [ka]

[0060] (In general formula (V), ring A 51 R is an aromatic hydrocarbon ring having 6 to 20 carbon atoms. 51 is a hydrogen atom, a halogen atom, a carboxy group, an alkyl group having from 1 to 20 carbon atoms, an alkoxy group having from 1 to 20 carbon atoms, an alkyloxycarbonyl group having from 1 to 20 carbon atoms, an alkylcarbonyloxy group having from 1 to 20 carbon atoms, an aryl group having from 6 to 20 carbon atoms, an aryloxy group having from 6 to 20 carbon atoms, an aralkyl group having from 7 to 20 carbon atoms, or an aralkyloxy group having from 7 to 20 carbon atoms. 51 is ring A 51 may be bonded to form a ring structure. n51 is an integer of 1 or more and 10 or less.

[0061] Ring A 51 Ring A may be a monocyclic ring or a polycyclic ring such as a condensed ring. 51 Specific examples of the ring A include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a naphthacene ring, a chrysene ring, a pyrene ring, a triphenylene ring, a pentalene ring, an azulene ring, a heptalene ring, an indacene ring, a biphenylene ring, an acenaphthylene ring, an aceanthrylene ring, and an acephenanthrylene ring. 51As the ring, a benzene ring, a naphthalene ring, or an anthracene ring is preferable, and a benzene ring is more preferable.

[0062] The hydroxy group shown in general formula (V) is 51 The ring A is bonded to an aromatic carbon atom and has phenolic properties. 51 and n51 R 51 The aromatic hydrocarbon group having the formula may be a substituted or unsubstituted monovalent aromatic hydrocarbon group, such as an aryl group.

[0063] R 51 is a ring A except for hydrogen atoms. 51 Ring A is a substituent of 51 As shown in general formula (V), it has one hydroxyl group and n51 R 51 There are n51 R 51 are each independently, R 51 Different rings may be selected from the group exemplified in the above, or two or more of the same rings may be selected. 51 is the above R 51 Besides, Ring A 51 The ring A may have a hydrogen atom and / or a substituent bonded to the carbon atom constituting the ring A. 51 The hydrogen atoms, substituents and functional groups bonded to the carbon atoms constituting the formula (V) are each independently one hydroxyl group and n51 R 51 Only this is acceptable.

[0064] [Blocking agent which is an aliphatic hydroxy compound] Examples of aliphatic hydroxy compounds preferred as blocking agents include aliphatic hydroxy compounds represented by the following general formula (VI).

[0065] [ka]

[0066] (In general formula (VI), R 61is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 24 carbon atoms, which may have an ether group, a carbonyl group, or an ester group.

[0067] R 61 R is a monovalent aliphatic hydrocarbon group. 61 The number of carbon atoms in the aliphatic hydrocarbon group in R is 1 or more and 24 or less, preferably 1 or more and 20 or less, and more preferably 1 or more and 12 or less. 61 The aliphatic hydrocarbon group in may be saturated or unsaturated. One hydroxy group shown in general formula (VI) is R 61 It is bonded to a saturated carbon atom in and has alcoholic properties.

[0068] [Secondary amine compound blocking agent] A secondary amine compound preferred as a blocking agent includes a secondary amine compound represented by the following general formula (VII) (hereinafter, sometimes referred to as "secondary amine compound (VII)").

[0069] [ka]

[0070] (In general formula (VII), R 71 and R 72 R is each independently a monovalent organic group. 71 and R 72 may be bonded to each other to form a ring structure via a carbon-carbon bond, a carbon-oxygen-carbon bond, or a carbon-nitrogen-carbon bond.

[0071] Among them, R 71 and R 72 R is preferably a monovalent aliphatic hydrocarbon group having 1 to 70 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 70 carbon atoms, which may have a substituted or unsubstituted ether group, carbonyl group, or ester group. 71 and R 72is preferably an organic group that does not contain active hydrogen, and more preferably an organic group that does not contain a substituted or unsubstituted amino group.

[0072] R 71 and R 72 Examples of the aliphatic hydrocarbon group in R include an alkyl group and a cycloalkyl group. 71 and R 72 The number of carbon atoms in the aliphatic hydrocarbon group in R is preferably 1 or more and 70 or less, more preferably 1 or more and 20 or less, further preferably 1 or more and 12 or less, and particularly preferably 1 or more and 10 or less. 71 and R 72 Examples of the substituent on the aliphatic hydrocarbon group in the formula include a hydroxyl group, a cyano group, and a halogen atom.

[0073] R 71 and R 72 Examples of the aromatic hydrocarbon group in R include an aryl group and an aralkyl group. 71 and R 72 The number of carbon atoms in the aromatic hydrocarbon group in R is preferably 6 or more and 70 or less, more preferably 6 or more and 20 or less, even more preferably 6 or more and 12 or less, and particularly preferably 6 or more and 10 or less. 71 and R 72 Examples of the substituent on the aromatic hydrocarbon group in the formula (I) include an aliphatic hydrocarbon group, a hydroxyl group, a cyano group, and a halogen atom.

[0074] R 71 and R 72 When they are bonded to each other to form a ring structure, R 71 and R 72 The group formed by bonding together is a divalent organic group. 71 and R 72 Examples of the group formed by bonding to each other include a substituted or unsubstituted ether group, a carbonyl group, an ester group, and a substituted imino group (-N(-R 73 )-), -CH=N- group, substituted amide group (-C(=O)-N(-R 74 )-) or a substituted imido group (-C(=O)-N(-R 75Examples of the divalent aliphatic hydrocarbon group having 1 to 70 carbon atoms and a divalent aromatic hydrocarbon group having 6 to 70 carbon atoms, which may have the formula R 73 , R 74 and R 75 Examples of the alkyl group include monovalent aliphatic hydrocarbon groups and aromatic hydrocarbon groups.

[0075] ≪Second process≫ In the second step, either or both of the carbonate derivative (II) and the carbonate derivative (III) contained in the first blocked isocyanate composition obtained in the first step are converted to the structure (I) represented by the general formula (I), thereby obtaining a second blocked isocyanate composition in which either or both of the carbonate derivative (II) and the carbonate derivative (III) are reduced.

[0076] The reaction temperature and reaction pressure of the second step are not particularly limited, and may be the same as or different from those of the first step. The second step may be carried out in the same reaction mixture as the first step. From the viewpoint of continuous operability, the first step and the second step may be carried out in the same reaction apparatus.

[0077] The second step may include a step of recovering the solvent from a reaction apparatus in which the second step is carried out. When distillation separation is carried out in the step of recovering the solvent, the progress of the reaction can be promoted by actively extracting compounds derived from the carbonic acid derivative out of the system.

[0078] Either or both of the carbonic acid derivative (II) and the carbonic acid derivative (III) are derived from isocyanic acid and may induce clogging of piping and reduce continuous operability. In the second step, either or both of the carbonic acid derivative (II) and the carbonic acid derivative (III) are converted to the structure (I) represented by the general formula (I) to obtain a second blocked isocyanate composition in which either or both of the carbonic acid derivative (II) and the carbonic acid derivative (III) are reduced, thereby providing a production method with excellent continuous operability.

[0079] Either or both of the carbonic acid derivative (II) and the carbonic acid derivative (III) reduced by the second blocked isocyanate composition may be the same compound as either or both of the carbonic acid derivative (II) and the carbonic acid derivative (III) used in the first step, or may be different compounds. Of either or both of the carbonic acid derivative (II) and the carbonic acid derivative (III), it is preferable to reduce compounds that induce clogging of piping.

[0080] ≪Structure (I)≫ The structure (I) is represented by the following general formula (I).

[0081] [ka] (In general formula (I), R 1 and R 2 R is each independently a monovalent organic group. 1 and R 2 may each independently form a ring structure via a carbon-carbon bond, a carbon-oxygen-carbon bond, or a carbon-nitrogen-carbon bond. 3 is a hydrocarbon group having an aliphatic hydrocarbon group or an aromatic group.

[0082] [R 1 and R 2 ] In the above general formula (I), R 1 and R 2 R is each independently a monovalent organic group. 1 and R 2 may each independently form a ring structure via a carbon-carbon bond, a carbon-oxygen-carbon bond, or a carbon-nitrogen-carbon bond.

[0083] Among them, R 1 and R 2 are preferably each independently a monovalent aliphatic hydrocarbon group having 1 to 70 carbon atoms which may have a substituent, or a monovalent aromatic hydrocarbon group having 6 to 70 carbon atoms which may have a substituent.

[0084] R 1 and R2 When an aliphatic hydrocarbon group is selected in at least one of the above, the number of carbon atoms is preferably 1 or more and 70 or less, more preferably 1 or more and 20 or less, even more preferably 1 or more and 12 or less, and particularly preferably 1 or more and 10 or less. R 1 and R 2 Examples of the aliphatic hydrocarbon group in the formula (I) include linear alkyl groups, branched alkyl groups, and cycloalkyl groups, which may be unsubstituted or substituted. Examples of the substituents of these aliphatic hydrocarbon groups include hydroxyl groups, cyano groups, and halogen atoms. Examples of the halogen atoms of the substituents include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0085] R 1 and R 2 Specific examples of the aliphatic hydrocarbon group in include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, each isomer of pentyl, each isomer of hexyl, each isomer of heptyl, each isomer of octyl, each isomer of nonyl, each isomer of decyl, cyclopentyl, cyclohexyl, etc. Among these, unsubstituted aliphatic hydrocarbon groups having 1 to 12 carbon atoms are preferred, and methyl, ethyl, n-propyl, isopropyl, n-butyl, or isobutyl are preferred.

[0086] R 1 and R 2 When an aromatic hydrocarbon group is selected in at least one of the above, the number of carbon atoms is preferably 6 or more and 70 or less, more preferably 6 or more and 20 or less, even more preferably 6 or more and 12 or less, and particularly preferably 6 or more and 10 or less. R 1 and R 2 Examples of the aromatic hydrocarbon group in R include an aryl group, an aralkyl group, etc., which may be unsubstituted or substituted. Examples of the substituent of these aromatic hydrocarbon groups include an aliphatic hydrocarbon group, a hydroxyl group, a cyano group, a halogen atom, etc. 1 and R 2The aliphatic hydrocarbon group selected as the substituent of the aromatic hydrocarbon group in R 1 and R 2 Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like.

[0087] R 1 and R 2 Specific examples of the aromatic hydrocarbon group in include a phenyl group, a naphthyl group, an anthryl group, a pyrenyl group, a phenanthryl group, an o-tolyl group, a m-tolyl group, a p-tolyl group, a benzyl group, and a phenethyl group.

[0088] R 1 and R 2 When they are bonded to each other to form a ring structure, R 1 and R 2 The group formed by bonding together is a divalent organic group. 1 and R 2 The group in which the groups are bonded to each other is preferably a divalent aliphatic hydrocarbon group having 1 to 70 carbon atoms or a divalent aromatic hydrocarbon group having 6 to 70 carbon atoms, which may have a substituted or unsubstituted ether group, a carbonyl group, an ester group, an imino group (-NH-), an amide group or an imide group.

[0089] [R 3 ] In general formula (I), R 3 is a hydrocarbon group having an aliphatic hydrocarbon group or an aromatic group. R 3 Specific examples of the aliphatic hydrocarbon group in include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, each isomer of pentyl, each isomer of hexyl, each isomer of heptyl, each isomer of octyl, each isomer of nonyl, each isomer of decyl, cyclopentyl, cyclohexyl, etc. Among these, unsubstituted aliphatic hydrocarbon groups having 1 to 12 carbon atoms are preferred, and methyl, ethyl, n-propyl, isopropyl, n-butyl, or isobutyl are preferred.

[0090] R 3 In the case where an aromatic hydrocarbon group is selected, the number of carbon atoms is preferably 6 or more and 70 or less, more preferably 6 or more and 20 or less, further preferably 6 or more and 12 or less, and particularly preferably 6 or more and 10 or less. R 3 Examples of the aromatic hydrocarbon group in R include an aryl group, an aralkyl group, etc., which may be unsubstituted or substituted. Examples of the substituent of these aromatic hydrocarbon groups include an aliphatic hydrocarbon group, a hydroxyl group, a cyano group, a halogen atom, etc. 3 The aliphatic hydrocarbon group selected as the substituent of the aromatic hydrocarbon group in R 3 Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like.

[0091] R 3 Specific examples of the aromatic hydrocarbon group in include a phenyl group, a naphthyl group, an anthryl group, a pyrenyl group, a phenanthryl group, an o-tolyl group, a m-tolyl group, a p-tolyl group, a benzyl group, and a phenethyl group.

[0092] The compound (I) is preferably a compound represented by the following general formula (I-1).

[0093] [ka] [In general formula (I-1), R 11 is a substituted or unsubstituted monovalent aliphatic hydrocarbon group having from 1 to 70 carbon atoms, or a substituted or unsubstituted monovalent aromatic hydrocarbon group having from 6 to 70 carbon atoms, R 12 R is a substituted or unsubstituted monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 70 carbon atoms. 13 is a substituted or unsubstituted monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 70 carbon atoms.]

[0094] In general formula (I-1), R 11 R is a substituted or unsubstituted monovalent aliphatic hydrocarbon group having 1 to 70 carbon atoms, or a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 70 carbon atoms. 11 Specific examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, each isomer of pentyl, each isomer of hexyl, each isomer of heptyl, each isomer of octyl, each isomer of nonyl, each isomer of decyl, cyclopentyl, cyclohexyl, phenyl, benzyl, o-tolyl, m-tolyl, p-tolyl, etc. Among these, unsubstituted aliphatic hydrocarbon groups having 1 to 12 carbon atoms are preferred, and methyl, ethyl, n-propyl, isopropyl, n-butyl, or isobutyl are preferred.

[0095] In general formula (I-1), R 12 R is a substituted or unsubstituted monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 70 carbon atoms. 12 Specific examples of the alkyl group include a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, each isomer of a pentyl group, each isomer of a hexyl group, each isomer of a heptyl group, each isomer of an octyl group, each isomer of a nonyl group, each isomer of a decyl group, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, an o-tolyl group, a m-tolyl group, a p-tolyl group, etc. Among these, an unsubstituted aliphatic hydrocarbon group having 1 to 12 carbon atoms is preferred, and a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, or an isobutyl group is preferred.

[0096] In general formula (I-1), R 13 R is a substituted or unsubstituted monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 70 carbon atoms. 13Examples of R include substituted or unsubstituted monovalent aliphatic hydrocarbon groups having 1 to 12 carbon atoms and monovalent aromatic hydrocarbon groups having 6 to 12 carbon atoms. 13 Specific examples of such alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, each isomer of pentyl, each isomer of hexyl, each isomer of heptyl, each isomer of octyl, each isomer of nonyl, each isomer of decyl, cyclopentyl, cyclohexyl, phenyl, benzyl, o-tolyl, m-tolyl, and p-tolyl.

[0097] In general formula (I-1), R 13 When R is a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, it is preferably a phenyl group which may have a substituent. 13 Examples of the substituent that the phenyl group may have include an aliphatic hydrocarbon group or an aromatic hydrocarbon group, such as an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms. When the substituent on the benzene ring has an ether group, examples of the substituent include an alkoxy group having from 1 to 12 carbon atoms, an aryloxy group having from 6 to 12 carbon atoms, and an aralkyloxy group having from 7 to 12 carbon atoms. When the substituent on the benzene ring has a carbonyl group, examples of the substituent include an alkylcarbonyl group having from 1 to 12 carbon atoms, an arylcarbonyl group having from 6 to 12 carbon atoms, and an aralkylcarbonyl group having from 7 to 12 carbon atoms.

[0098] When the substituent on the benzene ring has an ester group, examples of the ester group include an alkoxycarbonyl group or an alkylcarbonyloxy group having 1 to 12 carbon atoms, an aryloxycarbonyl group or an arylcarbonyloxy group having 6 to 12 carbon atoms, or an aralkyloxycarbonyl group or an aralkylcarbonyloxy group having 7 to 12 carbon atoms.

[0099] Specific examples of the substituent on the benzene ring include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, each isomer of pentyl, each isomer of hexyl, each isomer of heptyl, each isomer of octyl, each isomer of nonyl, each isomer of decyl, cyclopentyl, cyclohexyl, phenyl, benzyl, o-tolyl, m-tolyl, p-tolyl, cumyl, etc. Among these, unsubstituted aliphatic hydrocarbon groups having 1 to 12 carbon atoms are preferred, and methyl, ethyl, n-propyl, isopropyl, n-butyl, or isobutyl are preferred.

[0100] The compound (I) is preferably a compound represented by the following general formula (I-2).

[0101] [ka] [In general formula (I-2), R 22 R is a substituted or unsubstituted monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 70 carbon atoms. 23 is a substituted or unsubstituted monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 70 carbon atoms.]

[0102] In general formula (I-2), R 22 is a substituted or unsubstituted monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 70 carbon atoms, and specific descriptions are given in the above R 12 This is similar to the explanation given in . In general formula (I-2), R 22 is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, or an unsubstituted phenyl group.

[0103] In general formula (I-2), R 23is a substituted or unsubstituted monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 70 carbon atoms, and specific descriptions are given in the above R 13 This is similar to the explanation given in . In general formula (I-2), R 23 R is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted phenyl group. 23 When is a phenyl group having a substituent, examples of the substituent include a linear or branched alkyl group having 1 to 10 carbon atoms.

[0104] The second blocked isocyanate composition may comprise one or more compounds selected from the group consisting of hydroxy compounds and one or more compounds selected from the group consisting of secondary amine compounds.

[0105] [Hydroxy compounds] The second blocked isocyanate composition may contain an unreacted hydroxy compound or secondary amine compound from the blocking agent used in the first step. That is, the hydroxy compound that may be contained in the second blocked isocyanate composition is an aromatic hydroxy compound represented by the general formula (V) above, or an aliphatic hydroxy compound represented by the general formula (VI) above.

[0106] The secondary amine compound that may be contained in the second blocked isocyanate composition is the secondary amine compound represented by the above general formula (VII).

[0107] [Strong base catalyst] The second blocked isocyanate composition preferably contains a strong base catalyst that forms a salt with one or more compounds selected from the group consisting of hydroxy compounds in an amount of 1 ppb by mass or more relative to the carbonic acid derivative represented by either one or both of the general formulas (II) and (III). The strong base catalyst which forms a salt with one or more compounds selected from the group consisting of hydroxy compounds includes, for example, metal compounds, specifically, sodium methoxide and potassium methoxide. EXAMPLES

[0108] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. All of the reagents used as raw materials were purified products.

[0109] [Examples 1 to 17] In a 500mL SUS pressure vessel equipped with a condensation tube filled with a filler (the condensate in the condensation tube is structured to enter a 500mL SUS pressure vessel) and an ammonia trap, a primary amine compound shown in (IV) of Table 1, a carbonic acid derivative shown in (II) and (III) of Table 1, and a blocking agent shown in (V) to (VII) of Table 1 were added, and the temperature inside the pressure vessel was set to 250°C, and the temperature of the condensation tube was set to 60°C. Nitrogen gas was also supplied from a nitrogen cylinder to the pressure vessel to adjust the absolute pressure to 450 kPa, and then the reaction was carried out for 3 hours. Then, a secondary amine compound shown in (VIII) of Table 1 and a catalyst shown in "Catalyst" of Table 1 were added to the reaction mixture, and the reaction was carried out under the reaction conditions shown in the "Second Step" of Table 1, namely, the reaction temperature (Tre), the reaction pressure by absolute pressure (Pre), the condensation tube temperature (Tco), and the reaction time (t). The carbonic acid derivative, the free blocking agent and the free secondary amine compound contained in the resulting reaction liquid were distilled off under reduced pressure to obtain a blocked isocyanate composition.

[0110] The resulting blocked isocyanate composition was analyzed to determine the mol% of the reaction product of the carbonic acid derivative and the blocking agent (simply referred to as "product" in Table 1), biuret, MPBIU, and the compound represented by general formula (I). The mol% of the compound represented by general formula (I) can be regarded as the mol% of structure (I).

[0111] [Comparative Example 1] A blocked isocyanate composition was produced in the same manner as in Examples 1 to 17, except that in the second step, the secondary amine compound shown in "(VIII)" in Table 1 and the metal chloride shown in "Catalyst" in Table 1 were not added to the reaction mixture.

[0112] In the following table, the abbreviations represent the following compounds.

[0113] (Primary amine compounds) HDA: 1,6-hexamethylenediamine IPDA: Isophoronediamine (mixture of isomers) TDA: Diaminotoluene (mixture of isomers) MDA: Diphenylmethanediamine (mixture of isomers)

[0114] (Carbonic acid derivatives) BIURET: Biuret MPBIU: 1-methyl-1-phenyl biuret

[0115] (Blocking agent) PhOH: Phenol o-cresol: o-cresol m-cresol p-cresol n-BuOH: normal butanol

[0116] (Secondary amine compounds) NMA: N-methylaniline NEA: N-ethylaniline NBA: N-butylaniline DPA: N,N-diphenylamine

[0117] (catalyst) MeONa: Sodium methoxide KOCH3: Potassium methoxide

[0118] (I) Compounds (I)-1 to (I)-8 represented by general formula (I) each have the following structure: In the following structure, Me represents a methyl group, and Et represents an ethyl group.

[0119] [ka]

[0120] [ka] [Table 1]

[0121] As can be seen from Table 1, when a free carbonic acid derivative was converted to the structure represented by general formula (I), the amount of the reaction product between the carbonic acid derivative and the blocking agent was reduced. The reaction product between the carbonic acid derivative and the blocking agent is a compound corresponding to either or both of carbonic acid derivative (II) and carbonic acid derivative (III). When the free carbonic acid derivative was not converted to the structure represented by the general formula (I), a large amount of the carbonic acid derivative consisting of the reaction product between the carbonic acid derivative and the blocking agent remained. [Industrial Applicability]

[0122] According to the method for producing a blocked isocyanate composition of the present embodiment, a method for producing a blocked isocyanate composition having excellent continuous operability can be provided.

Claims

1. A first step of reacting a primary amine compound, a carbonic acid derivative represented by any one or both of the following general formulas (II) and (III), and a blocking agent by heat treatment to obtain a first blocked isocyanate composition; A method for producing a blocked isocyanate composition, comprising a second step of converting a carbonic acid derivative represented by either one or both of the following general formulas (II) and (III) contained in the first blocked isocyanate composition to a structure represented by the following general formula (I) to obtain a second blocked isocyanate composition. [Case 1] (In general formula (I), R １ and R ２ R is each independently a monovalent organic group. １ and R ２ may each independently form a ring structure via a carbon-carbon bond, a carbon-oxygen-carbon bond, or a carbon-nitrogen-carbon bond. ３ is an aliphatic hydrocarbon group or a hydrocarbon group having an aromatic group. [Case 2] (In general formula (II), X １ is a monovalent organic group. [C3] (In general formula (III), X ２ and X ３ are each independently hydrogen or a monovalent organic group.

2. 2. The method for producing a blocked isocyanate composition according to claim 1, wherein the blocking agent in the first step comprises one or more compounds selected from the group consisting of hydroxy compounds, amine compounds, and ammonia.

3. The method for producing a blocked isocyanate composition according to claim 1 or 2, wherein the primary amine compound in the first step is an amine compound represented by the following general formula (IV): [C4] (In general formula (IV), R ４１is an organic group having a valence of n41. n41 is an integer of 1 to 12.

4. 3. The method for producing a blocked isocyanate composition according to claim 1, wherein the blocking agent in the first step is an aromatic hydroxy compound represented by the following general formula (V): [C5] (In general formula (V), ring A ５１ R is an aromatic hydrocarbon ring having 6 to 20 carbon atoms. ５１ is a hydrogen atom, a halogen atom, a carboxy group, an alkyl group having from 1 to 20 carbon atoms, an alkoxy group having from 1 to 20 carbon atoms, an alkyloxycarbonyl group having from 1 to 20 carbon atoms, an alkylcarbonyloxy group having from 1 to 20 carbon atoms, an aryl group having from 6 to 20 carbon atoms, an aryloxy group having from 6 to 20 carbon atoms, an aralkyl group having from 7 to 20 carbon atoms, or an aralkyloxy group having from 7 to 20 carbon atoms. ５１ is ring A ５１ may be bonded to form a ring structure. n51 is an integer of 1 or more and 10 or less.

5. 3. The method for producing a blocked isocyanate composition according to claim 1, wherein the blocking agent in the first step is an aliphatic hydroxy compound represented by the following general formula (VI): [C6] (In general formula (VI), R ６１ is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 24 carbon atoms, which may have an ether group, a carbonyl group, or an ester group.

6. The method for producing a blocked isocyanate composition according to claim 1 or 2, wherein the blocking agent in the first step is a secondary amine compound represented by the following general formula (VII): [C7] (In general formula (VII), R ７１ and R ７２ R is each independently a monovalent organic group. ７１ and R ７２may be bonded to each other to form a ring structure via a carbon-carbon bond, a carbon-oxygen-carbon bond, or a carbon-nitrogen-carbon bond.

7. 3. The method for producing a blocked isocyanate composition according to claim 1 or 2, wherein the second blocked isocyanate composition comprises one or more compounds selected from the group consisting of hydroxy compounds and one or more compounds selected from the group consisting of secondary amine compounds.

8. 3. The method for producing a blocked isocyanate composition according to claim 1 or 2, wherein the second blocked isocyanate composition contains a strong base catalyst that forms a salt with one or more compounds selected from the group consisting of hydroxy compounds in an amount of 1 ppb by mass or more relative to the carbonic acid derivative represented by either one or both of the general formulas (II) and (III).

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