Method for producing blocked isocyanate compound

Abstract

To provide a method for producing a blocked isocyanate compound with less increase in by-product formation.SOLUTION: A method for producing a blocked isocyanate compound includes a reaction step for reacting a compound represented by the following general formula (I) with an organic amine. In the general formula (I), R1 and R2 independently represent a monovalent organic group. R1 and R2 may form, independently, a ring structure via a carbon-carbon bond, carbon-oxygen-carbon bond or carbon-nitrogen-carbon bond. R3 is an aliphatic hydrocarbon group or a hydrocarbon group with an aromatic group.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a blocked isocyanate compound. [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 1,6-hexamethylene diisocyanate by thermally decomposing 1,6-hexamethylene dicarbamic acid ester in the presence of a specific catalyst. In addition, 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.

[0004] In addition, isocyanates are highly reactive and easily react with compounds such as water. For this reason, in order to improve stability, they are sometimes converted to blocked isocyanates, and when used, the blocking agent is dissociated by heating to regenerate the isocyanate. Blocked isocyanates have low reactivity with active hydrogen compounds, can be stored stably, and are less toxic than isocyanates, making them useful as one-component paints, adhesives, and molding compounds.

[0005] In addition, blocked isocyanates have the property of dissociating into an isocyanate and a blocking agent by thermal decomposition. Therefore, blocked isocyanates can be decomposed into an isocyanate and a blocking agent by thermal decomposition, and the resulting isocyanate and blocking agent can be separated after or simultaneously with the thermal decomposition. The separated isocyanate and blocking agent are useful because they can be used as raw materials when producing isocyanates.

[0006] There are various known methods for producing blocked isocyanates, including, for example, a method for producing a blocked isocyanate by directly reacting an isocyanate with a blocking agent, a method for producing a blocked isocyanate by reacting a carbamic acid chloride obtained by reacting an amine with phosgene with a blocking agent, a method for producing a blocked isocyanate by reacting a carbamic acid with a blocking agent and a condensing agent, a method for producing a blocked isocyanate containing a compound derived from a carbonic acid derivative by reacting an amine with a carbonic acid derivative, and a method for producing a blocked isocyanate by reacting an amine with a carbonic acid derivative and a blocking agent.

[0007] In a method for producing a blocked isocyanate containing a compound derived from a carbonic acid derivative by reacting an amine with a carbonic acid derivative, the produced blocked isocyanate reacts with the remaining raw material amine, causing a side reaction to produce a ureylene group, as described in Patent Document 3. Therefore, in order to produce a blocked isocyanate with high efficiency, it is necessary to suppress this side reaction. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 6-239826 [Patent Document 2] Japanese Patent Application Publication No. 64-85956 [Patent Document 3] Patent Publication No. 2022-180170 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for efficiently producing a blocked isocyanate compound while suppressing the production of by-products having a ureylene group. [Means for solving the problem]

[0010] That is, the present invention includes the following aspects.

[0011] [1] A method for producing a blocked isocyanate compound, comprising a reaction step of reacting a compound represented by the following general formula (I) with an organic amine: [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. [2] The method for producing a blocked isocyanate compound according to [1], wherein the organic amine is an amine compound represented by the following general formula (II): [ka] (In general formula (II), R 21 is an organic group having a valence of n21. n21 is an integer of 1 to 12. [3] R in the above general formula (I) 3 is a group represented by the following general formula (R3)-1. [ka] (In general formula (R3)-1, ring A 31R is an aromatic hydrocarbon ring having 6 to 20 carbon atoms. 31 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. 31 is ring A 31 may bond to form a ring structure. n31 is an integer of 0 to 10. * indicates the bonding site with the oxygen atom. Effect of the Invention

[0012] According to the method for producing a blocked isocyanate compound of the above embodiment, it is possible to provide a method for efficiently producing a blocked isocyanate compound while suppressing the production of by-products having a ureylene group. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 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.

[0014] 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.

[0015] <Method for producing blocked isocyanate compound> The present embodiment is a method for producing a blocked isocyanate compound, which includes a reaction step of reacting a compound represented by the following general formula (I) with an organic amine. Hereinafter, the compound represented by the following general formula (I) will be referred to as "compound (I)".

[0016] [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.

[0017] The present inventors have been able to provide a method for efficiently producing a blocked isocyanate compound while suppressing the production of by-products having a ureylene group, by reacting compound (I) with an organic amine to produce a blocked isocyanate compound. The production method of the present invention will now be described.

[0018] <Reaction process> In the reaction step in the method for producing a blocked isocyanate compound according to this embodiment, compound (I) is reacted with an organic amine to obtain a blocked isocyanate compound.

[0019] In the first reaction step, the ratio of the amounts of compound (I) and the organic amine added can be selected arbitrarily. When expressed as a mass ratio, it is usually preferable that compound (I) is present in an amount that is in excess of the organic amine. For example, the mass ratio of the amounts of organic amine and compound (I) added can be 1:1 to 1:999.

[0020] The reaction temperature is not particularly limited and is appropriately selected depending on the reaction rate between the compound (I) and the organic amine, 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.

[0021] The reaction pressure 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.

[0022] The reaction step may be carried out in the presence of oxygen. When the reaction step is carried out in the presence of oxygen, the amount of oxygen present in the blocked isocyanate production apparatus 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 blocked isocyanate compound production facility, it is necessary to reduce the leakage of air into the production facility, which makes the design criteria for the facility stricter and causes an increase in facility costs. From this viewpoint, it is preferable to control the oxygen concentration in the gas supplied to the reaction 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.

[0023] In the reaction step, any solvent may be used in any ratio. As the solvent, an inert solvent that does not have reactivity with compound (I) and organic amines is preferable. As such a solvent, an ester solvent, an ether solvent, a phosphate solvent, a hydrocarbon solvent, an aromatic hydrocarbon solvent, or a carbonic acid derivative solvent is preferable.

[0024] In the reaction step, the reaction mixture containing the compound (I) and the organic amine 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 of the compound (I) and the organic amine, but may cause thermal denaturation, deterioration, and coloration. Therefore, 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 organic amine compound.

[0025] In the reaction step, the reaction mixture containing compound (I) and an organic amine may contain an organic acid, an inorganic acid, an organic base, or an inorganic base. These acids and bases act as catalysts in the production process of blocked isocyanates, can reduce the temperature required for the reaction, and promote the reaction between the primary amine compound and the carbonic acid derivative. In addition, it is more preferable to contain an organic acid and / or an inorganic acid that forms a salt with the primary amine compound, because this reduces the reactivity between the primary amine compound and the blocked isocyanate compound and suppresses the generation of ureylene groups.

[0026] In the reaction step, the blocked isocyanate compound is obtained as a composition containing the blocked isocyanate compound (hereinafter, may be referred to as a "blocked isocyanate composition").

[0027] The blocked isocyanate composition means a composition containing more than 0 wt% and 100 wt% 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.

[0028] 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.

[0029] (Reaction Apparatus) The reaction apparatus is not particularly limited, and a known apparatus for producing a blocked isocyanate can be used. For example, a method of adding a mixture containing a primary amine compound and compound (I) into a container connected to one or more devices selected from the group consisting of a condensation device and a treatment device, heating the container to produce a blocked isocyanate compound, and then or simultaneously, introducing steam containing a compound derived from a carbonic acid derivative into a condensation device or treatment device to synthesize a blocked isocyanate compound in a batch system, or a method of continuously introducing a mixture containing a primary amine compound and compound (I) into a distillation column heated to a predetermined reaction temperature, separating steam containing a compound derived from a carbonic acid derivative produced simultaneously with the production of a blocked isocyanate compound, and continuously obtaining a blocked isocyanate compound can be used. In addition, it is also possible to partially or completely react a primary amine compound and compound (I) in the presence or absence of a blocking agent, and then produce a blocked isocyanate compound from the resulting reaction product.

[0030] In the production apparatus for a blocked isocyanate compound, the material of the portion that comes into contact with the organic amine, compound (I), the blocked isocyanate compound, and other components may be any known material as long as it does not adversely affect the modification, etc., of the organic amine, compound (I), the blocked isocyanate compound, and other components. Specific examples of such materials include steel, stainless steel, ceramic, carbon, and materials lined with these materials.

[0031] ≪Compound (I)≫ Compound (I) is represented by the following general formula (I). Compound (I) has an asymmetric structure with a carbonyl group at the center, and in an addition-elimination reaction with an organic amine, a compound having a hydroxyl group is highly selectively eliminated to form a stable blocked isocyanate group. The resulting blocked isocyanate group has a low reactivity with an organic amine, and thus has the characteristic that the formation of a ureylene group is suppressed. Compound (I) is also represented by the general formula (I) where R 1 , R 2In comparison with a compound in which any one of the above is hydrogen, the resulting blocked isocyanate group has a low reactivity with an organic amine, and therefore the formation of a ureylene group is suppressed.

[0032] [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.

[0033] [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.

[0034] 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.

[0035] R 1 and R 2 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 2Examples 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.

[0036] 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.

[0037] 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 2 The 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.

[0038] 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.

[0039] 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.

[0040] [R 3 ] In general formula (I), R 3 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. 3 When R is an aromatic hydrocarbon group, the reactivity of the organic amine with the compound (I) is improved, and a blocked isocyanate group is efficiently formed, which is more preferable. 3 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.

[0041] In general formula (I), R 3 When R is a monovalent aromatic hydrocarbon group having 6 to 70 carbon atoms, it is preferably a phenyl group which may have a substituent.3 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.

[0042] 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.

[0043] 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.

[0044] In general formula (I), R 3 is preferably a group represented by the following general formula (R3)-1.

[0045] [ka] (In general formula (R3)-1, ring A 31 R is an aromatic hydrocarbon ring having 6 to 20 carbon atoms. 31 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. 31 is ring A 31 may bond to form a ring structure. n31 is an integer of 0 to 10. * indicates the bonding site with the oxygen atom.

[0046] Ring A 31 Ring A may be a monocyclic ring or a polycyclic ring such as a condensed ring. 31 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. 31 As the ring, a benzene ring, a naphthalene ring, or an anthracene ring is preferable, and a benzene ring is more preferable.

[0047] R 31 is a ring A except for hydrogen atoms. 31 Ring A is a substituent of 31 As shown in the general formula (R3)-1, n31 R 31 It has n31 R 31 are each independently, R 31 Different groups may be selected from the group exemplified in the above, or two or more of the same groups may be selected.

[0048] R 31is 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. 31 is ring A 31 may be bonded to form a ring structure.

[0049] The group represented by the general formula (R3)-1 is 31 -1~R 31 -8 is preferred.

[0050] [ka]

[0051] The compound (I) is preferably a compound represented by the following general formula (I-1).

[0052] [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.]

[0053] 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. 11Specific 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.

[0054] 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.

[0055] 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. 13 Examples 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. 13Specific 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] The compound (I) is preferably a compound represented by the following general formula (I-2).

[0060] [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.]

[0061] 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.

[0062] 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.

[0063] <Organic amines> The organic amine is preferably an amine compound represented by the following general formula (II) (hereinafter, sometimes referred to as "primary amine compound (II)").

[0064] [ka]

[0065] In general formula (II), R 21 is an organic group having a valence of n21, where n21 is an integer of 1 or more and 12 or less.

[0066] R 21 is an organic group having a valence of n21. That is, it is an organic group having a valence of 1 to 12. Among them, R 21 is preferably an organic group consisting of carbon atoms, oxygen atoms and hydrogen atoms, and more preferably an organic group having no active hydrogen.

[0067] R 21The aliphatic hydrocarbon group in is preferably an alkylene group or an alkanetriyl group, a cycloalkyl group, a cycloalkylene group or a cycloalkanetriyl group, or a group composed of the alkyl group, the alkylene group or the alkanetriyl group and the cycloalkyl group, the cycloalkylene group or the cycloalkanetriyl group, and more preferably a linear or branched alkylene group or alkanetriyl group, a cycloalkylene group or a cycloalkanetriyl group, or a group composed of the alkylene group or the alkanetriyl group and the cycloalkyl group, the cycloalkylene group or the cycloalkanetriyl group.

[0068] Examples of the linear or branched alkylene group include a methylene group, an ethylene group, a propylene group, a trimethylene group, a pentylene group, an n-hexylene group, and a decamethylene group. Examples of the cycloalkylene group include a cyclobutylene group, a cyclopentylene group, and a cyclohexylene group.

[0069] Examples of the linear or branched alkanetriyl group include a hexanetriyl group, a nonanetriyl group, and a decanetriyl group.

[0070] Examples of the cycloalkanetriyl group include a cyclopropanetriyl group, a cyclobutanetriyl group, a cyclopentanetriyl group, and a cyclohexanetriyl group.

[0071] R 21 The aromatic hydrocarbon group in is preferably a substituted or unsubstituted group having an aromatic ring with 6 to 13 carbon atoms. Examples of the substituent include an alkyl group, an aryl group, and an aralkyl group. The aromatic ring may be an aromatic hydrocarbon ring or a heteroaromatic ring, and specific examples include a benzene ring, a naphthalene ring, and a pyridine ring.

[0072] Preferred primary amine compounds include monofunctional primary amine compounds, difunctional primary amine compounds, and polyfunctional primary amine compounds.

[0073] Examples of monofunctional primary amine compounds include methylamine, ethylamine, propylamine (each isomer), butylamine (each isomer), pentylamine (each isomer), hexylamine (each isomer), heptylamine (each isomer), octylamine (each isomer), nonylamine (each isomer), decylamine (each isomer), undecylamine (each isomer), dodecylamine (each isomer), tridecylamine (each isomer), tetradecylamine (each isomer), pentadecylamine (each isomer), primary amine compounds having a saturated hydrocarbon group, such as 2-aminomethyl acrylate, 2-aminoethyl acrylate, 2-aminopropyl acrylate (each isomer), 2-aminobutyl acrylate (each isomer), 2-aminomethyl methacrylate, 2-aminoethyl methacrylate, 2-aminopropyl methacrylate (each isomer), ... primary amine compounds having an unsaturated bond, such as (S)-2-amino-3-tert-butoxypropionate (each isomer), 2-aminobutyl methacrylate (each isomer), phenylamine, and benzylamine; methyl (S)-2-amino-3-tert-butoxypropionate, ethyl (S)-2-amino-3-tert-butoxypropionate, propyl (S)-2-amino-3-tert-butoxypropionate (each isomer), butyl (S)-2-amino-3-tert-butoxypropionate (each isomer), and (S)-2-amino- Primary amine compounds having an ether group, such as pentyl 3-tert-butoxypropionate (each isomer), hexyl (S)-2-amino-3-tert-butoxypropionate (each isomer), and dodecyl (S)-2-amino-3-tert-butoxypropionate (each isomer); primary amine compounds having a halogen group, such as fluorophenylamine (each isomer), chlorophenylamine (each isomer), bromophenylamine (each isomer), and iodophenylamine (each isomer);Examples of primary amine compounds having a carbonyl group include glycine methyl ester, glycine ethyl ester, glycine propyl ester (each isomer), glycine butyl ester (each isomer), glycine pentyl ester (each isomer), glycine hexyl ester (each isomer), glycine dodecyl ester (each isomer), leucine methyl ester, leucine ethyl ester, leucine propyl ester (each isomer), leucine butyl ester (each isomer), leucine pentyl ester (each isomer), leucine hexyl ester (each isomer), and leucine dodecyl ester (each isomer);

[0074] Examples of bifunctional primary amine compounds include dimethylene diamine, trimethylene diamine (each isomer), tetramethylene diamine (each isomer), pentamethylene diamine (each isomer), hexamethylene diamine (each isomer), heptamethylene diamine (each isomer), octamethylene diamine (each isomer), cyclohexane diamine (each isomer), methylcyclohexane diamine (each isomer), isophorone diamine (each isomer), dicyclohexylmethane diamine (each isomer), dimethylpropane diamine (each isomer), dicyclohexylmethane ... Methylpentanediamine (each isomer), dimethylhexanediamine (each isomer), dimethylheptanediamine (each isomer), dimethyloctanediamine (each isomer), dimethylnonanediamine (each isomer), dimethyldecanediamine (each isomer), methylethylpropanediamine (each isomer), methylethylbutanediamine (each isomer), methylethylpentanediamine (each isomer), methylethylhexanediamine (each isomer), methylethylheptanediamine (each isomer), methylethyloctanediamine (each isomer), Primary amine compounds having saturated hydrocarbon groups, such as diethylpropanediamine (each isomer), diethylpentanediamine (each isomer), diethylhexanediamine (each isomer), diethylheptanediamine (each isomer), diethyloctanediamine (each isomer), and diethylnonanediamine (each isomer); diphenylmethanediamine (each isomer), tolylenediamine (each isomer), naphthalenediamine (each isomer), xylylenediamine (each isomer), tetramethylxylylenediamine (each isomer), methylenebis(diisoamine), Examples of the primary amine compounds having an unsaturated hydrocarbon group include primary amine compounds having an ester group such as lysine methyl ester, lysine ethyl ester, lysine propyl ester (each isomer), lysine butyl ester (each isomer), lysine pentyl ester (each isomer), and lysine hexyl ester (each isomer).

[0075] Examples of polyfunctional amines include propanetriamine, butanetriamine (each isomer), pentanetriamine (each isomer), hexanetriamine (each isomer), heptanetriamine (each isomer), octanetriamine (each isomer), nonanetriamine (each isomer), decanetriamine (each isomer), undecanetriamine (each isomer), dodecanetriamine (each isomer), tridecanetriamine (each isomer), tetradecanetriamine (each isomer), pentadecanetriamine (each isomer), hexadecanetriamine (each isomer), heptadecanetriamine (each isomer), and octadecanetriamine. primary amine compounds having a saturated hydrocarbon group, such as methyl amine (each isomer), nonadecanetriamine (each isomer), and icosanetriamine (each isomer); primary amine compounds having an unsaturated hydrocarbon group, such as polymeric MDA (each isomer); primary amine compounds having an ester group, such as 2-aminoethyl 2,6-diaminehexanoate; and other primary amine compounds having a difunctional or higher amino group with an isocyanurate group, primary amine compounds having a difunctional or higher amino group with a biuret group, and primary amine compounds having a difunctional or higher amino group with an allophanate group. EXAMPLES

[0076] 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.

[0077] [Example 1] 10 parts by mass of hexamethylenediamine (HDA) and 100 parts by mass of compound (I)-1 (the specific structure will be described later) were added to a 500 mL SUS pressure vessel, and the internal temperature of the 500 mL pressure vessel was set to 150° C., and the reaction was carried out for 2 hours. The liquid after the reaction was measured by 1H NMR, and it was found to contain 8 mol % of amino groups, 0 mol % of ureylene groups, and 90 mol % of blocked isocyanate groups.

[0078] [Examples 2 to 7] The blocked isocyanate compounds of Examples 2 to 7 were obtained in the same manner as in Example 1, except that compound (I)-1 and hexamethylenediamine were changed to the materials shown in Table 1 below.

[0079] [Comparative Example 1] The blocked isocyanate compound of Comparative Example 1 was obtained in the same manner as in Example 1, except that compound (I)-1 was changed to diphenyl carbonate (DPC).

[0080] [Comparative Example 2] 10 parts by mass of hexamethylenediamine (HDA), 30 parts by mass of urea, and 70 parts by mass of dibutylamine (DBA) were added to a 500 mL SUS pressure vessel equipped with an ammonia trap, and the internal temperature of the 500 mL pressure vessel was set to 150°C and reacted for 2 hours. 1H NMR measurement of the liquid after the reaction revealed that it contained 27 mol% amino groups, 21 mol% ureylene groups, and 49 mol% blocked isocyanate groups.

[0081] Tables 1 and 2 show the abbreviations of the obtained blocked isocyanate compounds, and the contents of amino groups, ureylene (-NHCONH-) groups, and blocked isocyanate (BL-NCO) groups.

[0082] In the following table, the abbreviations represent the following compounds.

[0083] (Primary amine compounds) HDA: 1,6-hexamethylenediamine IPDA: isophorone diamine isomer mixture MDA: Diphenylmethanediamine isomer mixture TDA: Toluenediamine isomer mixture

[0084] (Blocking agent) DBA: Dibutylamine

[0085] (others) DPC: Diphenyl carbonate

[0086] In the table below, the structure of compound (I) is as follows.

[0087] [ka]

[0088] [Table 1]

[0089] [Table 2]

[0090] As can be seen from Tables 1 and 2, when compound (I) was reacted with an organic amine, the yield of blocked isocyanate groups (NCO group mol %) improved without increasing the ureylene groups.

[0091] On the other hand, when the organic amine was reacted without the presence of compound (I), the amount of ureylene groups produced increased, and it was confirmed that the amount of by-products produced also increased. [Industrial Applicability]

[0092] According to the method for producing a blocked isocyanate compound of the present embodiment, it is possible to provide a method for producing a blocked isocyanate compound in which the amount of by-products produced is reduced.

Claims

1. A method for producing a blocked isocyanate compound, comprising a reaction step of reacting a compound represented by the following general formula (I) with an organic amine: 【Chemistry 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.

2. The method for producing a blocked isocyanate compound according to claim 1, wherein the organic amine is an amine compound represented by the following general formula (II): 【Chemistry 2】 (In general formula (II), R ２１ is a monovalent organic group. n21 is an integer of 1 or more and 12 or less.

3. R in the general formula (I) ３ is a group represented by the following general formula (R3)-1. 【Chemistry 3】 (In general formula (R3)-1, ring A ３１ R is an aromatic hydrocarbon ring having 6 to 20 carbon atoms. ３１ 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. ３１ is ring A ３１ may be bonded to form a ring structure. n31 is an integer of 0 to 10. * indicates the bonding site with the oxygen atom.

Images