Modified polyisocyanate, coating and coated metal material

Abstract

The present invention addresses the problem of providing a modified polyisocyanate which is applicable to a coating material for single application, the coating material exhibiting high adhesion even to a nonferrous metal. The present invention provides: a modified polyisocyanate which is a reaction product that is obtained using, as a starting material, a component that contains (a1) an alkoxysilane having a primary amino group, (a2) an unsaturated carboxylic acid alkyl ester or (a3) a saturated carboxylic acid alkyl ester, and (a4) a polyisocyanate, wherein the unsaturated carboxylic acid alkyl ester (a2) is composed of at least one compound that is selected from the group consisting of (a2-1) a branched alkyl ester of an unsaturated dicarboxylic acid and (a2-2) a branched alkyl ester of an unsaturated monocarboxylic acid, the branched alkyl ester optionally containing a heteroatom, or an alkyl ester having a cyclic structure; a method for producing this modified polyisocyanate; and a coating which contains this modified polyisocyanate.

Description

Modified polyisocyanates, coatings and painted metal materials

[0001] The present invention relates to modified polyisocyanates, coatings and painted metal materials.

[0002] Polyisocyanate compounds are highly reactive substances and are widely used as raw materials for chemical products such as polyurethane foams, sealants, adhesives, paints, etc. In recent years, modified polyisocyanates have been developed that have been modified in various ways depending on the functions required of these chemical products.

[0003] As an example of a modified polyisocyanate, Patent Document 1 describes a silyl-isocyanate obtained by reacting a polyisocyanate with a silane starting material, and discloses that this silyl-isocyanate has good adhesion to glass and is useful as a fixing agent to be used in combination with a polyurethane resin.

[0004] Furthermore, Patent Document 2 describes a reaction product of an amino-alkylalkoxysilane with a maleic acid ester or a fumaric acid ester, and discloses that this reaction product is useful as a modifier for polyisocyanates.

[0005] Furthermore, Patent Document 3 discloses a crosslinkable silyl group-containing urethane resin mixture obtained by reacting a compound containing two or more active hydrogens and one or more crosslinkable silyl groups in the molecule with an acrylic compound and / or a methacrylic compound, thereby obtaining a compound each containing one or more active hydrogens and one or more crosslinkable silyl groups in the molecule, with an isocyanate group-containing urethane prepolymer obtained by reacting an organic polyisocyanate with a polymer polyol under conditions where the isocyanate group is in excess relative to the active hydrogen.

[0006] JP-A-6-212141 JP-A-6-211879 JP-A-2001-323040

[0007] In recent years, the development of direct-to-metal coating has been anticipated. Direct-to-metal coating is a coating method that forms a protective coating film that combines corrosion resistance and weather resistance by simply applying a single type of paint directly to a metal surface. Metal coating typically involves a multi-layer finish, first applying a primer to inhibit rust and then a topcoat that provides excellent weather resistance and finish. In contrast, direct-to-metal coating achieves the desired performance with a single-layer finish, thereby reducing the number of processes and shortening construction time. However, the corrosion resistance and weather resistance of a coating film are generally incompatible, making it difficult to achieve both. Furthermore, non-ferrous metals have the problem of poor adhesion and peeling of coatings compared to ferrous metals, making it extremely difficult to develop a coating that combines excellent adhesion to non-ferrous metals with corrosion resistance and weather resistance.

[0008] Although the above Patent Documents 1 to 3 disclose various modified polyisocyanates, they do not disclose modified polyisocyanates that are applicable to one-coat paints having high adhesion to non-ferrous metals.

[0009] The present inventors have conducted extensive research into the above-mentioned problems. As a result, they have arrived at the use of a modified polyisocyanate modified with an alkoxysilane having a primary amino group and a specific unsaturated carboxylic acid alkyl ester or a saturated carboxylic acid alkyl ester. They have also found that this modified polyisocyanate is an excellent metal adhesion material, and that coatings containing this material have excellent adhesion to not only iron but also non-ferrous metals.

[0010] That is, the present invention provides: Item 1. A modified polyisocyanate for use as a curing agent for a coating together with an active hydrogen-containing compound, which is a reaction product of raw materials containing an alkoxysilane (a1) having a primary amino group, an unsaturated carboxylic acid alkyl ester (a2) or a saturated carboxylic acid alkyl ester (a3), and a polyisocyanate (a4), wherein the unsaturated carboxylic acid alkyl ester (a2) is at least one selected from the group consisting of a branched alkyl ester of an unsaturated dicarboxylic acid (a2-1), and an unsaturated monocarboxylic acid branched alkyl ester or an alkyl ester having a cyclic structure (a2-2), which may contain a heteroatom. Item 2. The modified polyisocyanate according to Item 1, wherein the alkoxysilane (a1) having a primary amino group is a compound represented by the following formula (1):

[0011]

[0012] In formula (1), R １ and R ２ are the same or different and each represents an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group, or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8 carbon atoms, preferably 1 to 5 carbon atoms, and n is an integer of 0 to 2. Item 3. The modified polyisocyanate according to Item 1 or 2, wherein the branched alkyl ester of unsaturated dicarboxylic acid (a2-1) is a compound represented by the following formula (2): ４ OC(=O)-HC=CH-C(=O)-OR ５ (2)

[0013] In formula (2), R ４ and R ５ and are the same or different and are branched alkyl groups having 1 to 8 carbon atoms. Item 4. The modified polyisocyanate according to Item 1 or 2, wherein the branched alkyl ester or cyclic alkyl ester (a2-2) of an unsaturated monocarboxylic acid which may contain a heteroatom is a compound represented by the following formula (3): H ２C=CH-C(=O)-OR ６ (3)

[0014] In formula (3), R ６ represents a group obtained by incorporating a heteroatom (e.g., an oxygen atom, a nitrogen atom, or a sulfur atom) into the molecule of a branched alkyl group or an alkyl group having a cyclic structure and having 3 to 18 carbon atoms, or an alkyl group or an arylalkyl group having a branched or cyclic structure and having 1 to 18 carbon atoms. Item 5. The modified polyisocyanate according to Item 1 or 2, wherein the saturated carboxylic acid alkyl ester (a3) ​​is a compound represented by the following formula (4): ７ -C(=O)-OR ８ (4)

[0015] In formula (4), R ７ and R ８ are the same or different and represent an alkyl group having 1 to 18 carbon atoms and having no unsaturated group, or a group formed by adding a heteroatom, such as an oxygen atom, a nitrogen atom, or a sulfur atom to the alkyl or arylalkyl group having 1 to 18 carbon atoms, and having no unsaturated group. Item 6: The modified polyisocyanate according to any one of Items 1 to 4, having a structure in which a secondary amino group of an N-position-modified alkoxysilane formed by adducting a primary amino group of the alkoxysilane (a1) with an unsaturated carbon-carbon bond of the unsaturated carboxylic acid alkyl ester (a2) is adducted to an isocyanate group of the polyisocyanate (a4). Item 7: The modified polyisocyanate according to any one of Items 1, 2, and 5, having a structure in which a secondary amide group of an N-position-modified alkoxysilane formed by reacting a primary amino group of the alkoxysilane (a1) with an ester group of the saturated carboxylic acid alkyl ester (a3) ​​is adducted to an isocyanate group of the polyisocyanate (a4). Item 8. The modified polyisocyanate according to Item 6, wherein the unsaturated carboxylic acid alkyl ester (a2) is a branched alkyl ester of an unsaturated dicarboxylic acid (a2-1), and the N-position-modified alkoxysilane is a compound represented by the following formula (5):

[0016]

[0017] In formula (5), R １and R ２ are the same or different and each represents an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group, or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8, preferably 1 to 5, carbon atoms; R ４ and R ５ are the same or different and are branched alkyl groups having 1 to 8 carbon atoms, and n is an integer of 0 to 2. Item 9. The modified polyisocyanate according to any one of Items 6 to 8, wherein the reaction ratio of the N-position-modified alkoxysilane having a secondary amino group with the polyisocyanate (a4) is a ratio such that the number of secondary amino groups is 40 or less per 100 moles of isocyanate groups. Item 10. The modified polyisocyanate according to Item 6, wherein the unsaturated carboxylic acid alkyl ester (a2) is a branched alkyl ester of an unsaturated monocarboxylic acid that may contain a heteroatom or an alkyl ester (a2-2) having a cyclic structure, and the N-position-modified alkoxysilane is a compound represented by the following formula (6):

[0018]

[0019] In formula (6), R １ and R ２ are the same or different and each represents an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group, or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8, preferably 1 to 5, carbon atoms; R ６is a group obtained by adding a heteroatom, such as an oxygen atom, a nitrogen atom, or a sulfur atom, to an alkyl group having 3 to 18 carbon atoms and having a branched or cyclic structure, or an alkyl group or arylalkyl group having 1 to 18 carbon atoms and having a branched or cyclic structure, and n is an integer of 0 to 2. Item 11. The modified polyisocyanate according to any one of Items 6 to 10, wherein the reaction ratio of the mixture containing the N-position-modified alkoxysilane having a secondary amino group with the polyisocyanate (a4) is such that the total number of moles of primary amino groups and secondary amino groups is 40 moles or less per 100 moles of isocyanate groups. Item 12. The modified polyisocyanate according to Item 7, wherein the N-position-modified alkoxysilane obtained by reacting the alkoxysilane (a1) with the saturated carboxylic acid alkyl ester (a3) ​​is an N-position acyl-modified compound having a secondary amide group, represented by the following formula (7):

[0020]

[0021] In formula (7), R １ and R ２ are the same or different and each represents an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group, or heteroaryl group having 1 to 18 carbon atoms; n is an integer of 0 to 2; R 3 is a linear or branched alkylene group having 1 to 8, preferably 1 to 5, carbon atoms; R ７ represents an alkyl group having 1 to 18 carbon atoms and having no unsaturated group, or a group having 1 to 18 carbon atoms and containing a heteroatom, such as an oxygen atom, a nitrogen atom, or a sulfur atom, in the alkyl molecule, and having no unsaturated group. Item 13. The modified polyisocyanate according to Item 1 or 12, produced by the following steps: (1) reacting an alkoxysilane (a1) having a primary amino group with a saturated carboxylic acid alkyl ester (a3) ​​in the presence of a basic catalyst; (2) adding an acidic compound; (3) removing part or all of the alcohol produced as a by-product to prepare an intermediate containing an N-acyl-modified product represented by the following formula (7); and (4) reacting the intermediate with a polyisocyanate (a4).

[0022]

[0023] In formula (7), R １ and R ２ are the same or different and each represents an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group, or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8 carbon atoms, preferably 1 to 5 carbon atoms, n is an integer of 0 to 2, and R ７ represents an alkyl group having 1 to 18 carbon atoms and having no unsaturated group, or a group having 1 to 18 carbon atoms and containing a heteroatom such as an oxygen atom, a nitrogen atom, or a sulfur atom in the alkyl molecule, and having no unsaturated group. Item 14. The modified polyisocyanate according to Item 12 or 13, wherein the reaction ratio of the N-acyl-modified product with the polyisocyanate (a4) is such that the total number of moles of secondary amide groups and primary amino groups per 100 moles of isocyanate groups is 40 moles or less. Item 15. A method for producing a modified polyisocyanate according to Item 1, comprising: (1) reacting an alkoxysilane (a1) having a primary amino group with a saturated carboxylic acid alkyl ester (a3) ​​in the presence of a basic catalyst; (2) adding an acidic compound; (3) removing a part or all of the alcohol produced as a by-product to prepare an intermediate containing an N-acyl-modified product represented by the following formula (7); and (4) reacting the intermediate with a polyisocyanate (a4).

[0024]

[0025] In formula (7), R １ and R ２ are the same or different and each represents an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group, or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8 carbon atoms, preferably 1 to 5 carbon atoms, n is an integer of 0 to 2, and R ７represents an alkyl group having 1 to 18 carbon atoms and having no unsaturated group, or a group having 1 to 18 carbon atoms and containing a heteroatom, such as an oxygen atom, a nitrogen atom, or a sulfur atom, in the alkyl molecule, and having no unsaturated group. Item 16. The modified polyisocyanate according to Item 6, wherein the unsaturated carboxylic acid alkyl ester (a2) is a branched alkyl ester or an alkyl ester (a2-2) having a cyclic structure, which may contain a heteroatom, of an unsaturated monocarboxylic acid, and the reaction of the N-position-modified alkoxysilane having a secondary amino group with the polyisocyanate (a4) is carried out in the presence of an alkoxysilane (a1) having a primary amino group and a by-product, a tertiary amino group-containing compound represented by the following formula (8):

[0026]

[0027] In formula (8), R １ and R ２ are the same or different and each represents an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group, or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8, preferably 1 to 5, carbon atoms; R ６is a group obtained by incorporating a heteroatom, such as an oxygen atom, a nitrogen atom, or a sulfur atom, into the molecule of an alkyl group having 3 to 18 carbon atoms and a branched or cyclic structure, or an alkyl group or arylalkyl group having 1 to 18 carbon atoms and a branched or cyclic structure, and n is an integer of 0 to 2. Item 17. The modified polyisocyanate according to any one of Items 1, 2, 5, 7, 12, 13, and 14, wherein the saturated carboxylic acid alkyl ester (a3) ​​is an alkyl ester of a linear carboxylic acid having two or more hydrogen atoms at the α-position, or an alkyl ester of a branched carboxylic acid having two hydrogen atoms at the α-position. Item 18. The method for producing the modified polyisocyanate according to Item 15, wherein the saturated carboxylic acid alkyl ester (a3) ​​is an alkyl ester of a linear carboxylic acid having two or more hydrogen atoms at the α-position. Item 19. A coating comprising an active hydrogen-containing compound and the modified polyisocyanate according to any one of Items 1 to 14 and 16 to 17. Item 20. The coating according to Item 19, wherein the active hydrogen-containing compound comprises an acrylic polyol and / or a bisaspartic acid ester derivative. Item 21. The coating according to Item 19 or 20, further comprising at least one member selected from the group consisting of a rust inhibitor, a catalyst, a color pigment, and an extender pigment. Item 22. The coating according to any one of Items 19 to 21, which is a one-coat paint. Item 23. A protective coating film formed by curing the coating according to any one of Items 19 to 22. Item 24. A coated metal material, in which the protective coating film according to any one of Items 19 to 22 is formed on a metal substrate.

[0028] As used herein, the singular forms (a, an, the, etc.) include both the singular and the plural, unless otherwise specified herein or clearly contradictory in the context. The modified polyisocyanate of the present invention has excellent storage stability and can be used as a metal adhesion promoter for coatings. By using this modified polyisocyanate, a coating can be obtained that forms a protective coating film with excellent adhesion to not only ferrous but also non-ferrous metals.

[0029] The modified polyisocyanate of the present invention is a reaction product obtained by using, as raw materials, components including an alkoxysilane (a1) having a primary amino group, an unsaturated carboxylic acid alkyl ester (a2) or a saturated carboxylic acid alkyl ester (a3), and a polyisocyanate (a4).

[0030] The raw material for the modified polyisocyanate of the present invention contains an unsaturated carboxylic acid alkyl ester (a2) or a saturated carboxylic acid alkyl ester (a3) ​​as a carboxylic acid alkyl ester. In a first embodiment, the present invention provides a modified polyisocyanate using the unsaturated carboxylic acid alkyl ester (a2) as a raw material (referred to as modified polyisocyanate (X)). In a second embodiment, the present invention provides a modified polyisocyanate using the saturated carboxylic acid alkyl ester (a3) ​​as a raw material (referred to as modified polyisocyanate (Y)).

[0031] When an unsaturated carboxylic acid alkyl ester (a2) is used as the carboxylic acid alkyl ester, the unsaturated carboxylic acid alkyl ester (a2) is at least one selected from the group consisting of a branched alkyl ester of an unsaturated dicarboxylic acid (a2-1), and a branched alkyl ester of an unsaturated monocarboxylic acid (a2-2) which may contain a heteroatom or an alkyl ester having a cyclic structure.

[0032] In the present invention, by using the unsaturated carboxylic acid alkyl ester (a2) or the saturated carboxylic acid alkyl ester (a3) ​​as a modifier, a modified polyisocyanate can be obtained that can be stably diluted in an organic solvent and has excellent storage stability, and together with an active hydrogen group-containing compound described below, it is possible to form a protective coating film that has excellent adhesion to various metal substrates.

[0033] In the present invention, when a group in a general formula such as Formula (1) or Formula (5) is substituted, unless otherwise specified, examples of the substituent include an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, a monoalkylamino group, a dialkylamino group, a carboxyl group, a hydroxyl group, a hydroxyalkyl group, a hydroxyalkoxy group, an aryl group, an aryloxy group, and a heteroaryl group.

[0034] In the present invention, unless otherwise specified, examples of each substituent include the following: An alkyl group refers to a linear, branched, or cyclic saturated hydrocarbon group unless otherwise specified. The number of carbon atoms in the alkyl group is not particularly limited, and examples include 1 to 18, 1 to 10, 1 to 8, 1 to 6, 1 to 4, and 1 to 3. Examples of such alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. Examples of cycloalkyl groups include cyclic hydrocarbon groups in which all carbon-carbon bonds are single bonds. Examples of the cycloalkyl group include those having 3 to 8 carbon atoms. More specifically, examples of the cycloalkyl group include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. Examples of hydroxyalkyl groups include the aforementioned alkyl groups substituted with one or more hydroxyl groups (e.g., 1 to 3, 1 to 2, 1, etc.). Examples of alkoxy groups include alkoxy groups in which the aforementioned alkyl moiety is the aforementioned alkyl group. Examples of hydroxyalkoxy groups include the aforementioned alkoxy groups substituted with one or more hydroxyl groups (e.g., 1 to 3, 1 to 2, 1, etc.). Examples of alkenyl groups include linear or branched hydrocarbon groups having a carbon-carbon double bond. The number of carbon atoms in the alkenyl group is not particularly limited, and examples include 2 to 18, 2 to 10, 2 to 8, 2 to 6, 2 to 4, and 2 to 3. The number of carbon-carbon double bonds in the alkenyl group is not limited, and examples include 1 to 2, preferably 1.Examples of such alkenyl groups include vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 1-pentenyl, 1,4-pentadienyl, 1-hexenyl, 1-heptenyl, 1-octenyl, 1-nonenyl, 1-decenyl, 2-undecenyl, 3-dodecenyl, 1-tridecenyl, 2-tetradecenyl, 3-pentadecenyl, 1-hexadecenyl, 2-heptadecenyl, and 3-octadecenyl. Alkynyl groups refer to linear or branched hydrocarbon groups having a carbon-carbon triple bond. The number of carbon atoms in the alkyl group is not particularly limited, and examples include 2 to 18, 2 to 10, 2 to 8, 2 to 6, 2 to 4, and 2 to 3. The number of carbon-carbon triple bonds in the alkynyl group is not limited, but may be, for example, 1 to 2, and preferably 1. Examples of such alkoxy groups include ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 1-pentynyl, 1,4-pentadiynyl, 1-hexynyl, 1-heptynyl, 1-octynyl, 1-nonynyl, 1-decynyl, 2-undecynyl, 3-dodecynyl, 1-tridecynyl, 2-tetradecynyl, 3-pentadecynyl, 1-hexadecynyl, 2-heptadecynyl, and 3-octadecynyl. Examples of cycloalkenyl groups include cyclic hydrocarbon groups having a carbon-carbon double bond and all other carbon-carbon bonds being single bonds. Examples of the number of carbon atoms include 3 to 8. The number of carbon-carbon double bonds in the cycloalkenyl group is not limited, but may be, for example, 1 to 2, and preferably 1. More specific examples of the cycloalkyl group include a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group, a cyclohexenyl group, a cyclohexedienyl group, a cycloheptenyl group, and a cyclooctenyl group. The aryl group refers to a monovalent group formed by eliminating one hydrogen atom from a monocyclic or polycyclic aromatic hydrocarbon compound, and examples include those having 6 to 18 carbon atoms.In the present invention, the monocyclic or polycyclic aromatic hydrocarbon compound may be any hydrocarbon containing an aromatic ring, and a group consisting of a cyclic structure may be substituted with one or more (e.g., 1 to 3, 1 to 2, or 1) acyclic hydrocarbons (e.g., linear or branched alkyl groups, alkenyl groups, alkynyl groups, etc. (preferably linear or branched alkyl groups, etc.)). Similarly, in the present invention, the aryl group includes not only groups consisting of a cyclic structure, but also groups in which a group consisting of a cyclic structure is substituted with one or more acyclic hydrocarbons. Examples of the aryl group include a phenyl group, a naphthyl group, an anthracenyl group, a diphenyl group, a methylphenyl group, a dimethylphenyl group, and a dodecylphenyl group. Examples of the arylalkyl group include the above-mentioned alkyl groups having one or more (typically one) aryl groups. Examples of heteroaryl groups include groups having a saturated or unsaturated 5- to 14-membered ring structure and containing at least one atom (e.g., 1 to 3, 1 to 2, 1, etc.) selected from the group consisting of oxygen, nitrogen, and sulfur atoms. Examples include tetrahydrofuryl, dihydrobenzofuranyl, pyridinyl, pyrimidinyl, thiophenyl, oxathiolanyl, quinolinyl, and benzoquinolinyl. Heteroaryl groups may be monocyclic or bicyclic. An alkyl group having a cyclic structure refers to a hydrocarbon group having a cyclic structure in at least a portion of its structure. Preferably, the alkyl group does not have a carbon-carbon double bond. An alkyl group having a cyclic structure may be a group consisting of a hydrocarbon having a cyclic structure (e.g., a cycloalkyl group, a bicycloalkyl group, etc.), or may be a group in which the hydrocarbon group having a cyclic structure is substituted with (e.g., 1 to 5, preferably 1 to 4) hydrocarbon groups (e.g., alkyl groups (preferably alkyl groups having 1 to 3 carbon atoms)). The number of carbon atoms in the alkyl group having a cyclic structure is not limited, and examples thereof include 6 to 23, and preferably 6 to 11. Examples of bicycloalkyl groups include monovalent groups obtained by eliminating one hydrogen atom from a fused ring having 5 to 8 carbon atoms, such as a bicyclo[1.1.1]pentanyl group, a bicyclo[2.1.1]hexanyl group, a bicyclo[2.2.1]heptanyl group, and a bicyclo[2.2.2]octanyl group.

[0035] <Alkoxysilane (a1) Having a Primary Amino Group> In the present invention, the alkoxysilane (a1) having a primary amino group is a compound represented by the following formula (1).

[0036]

[0037] In formula (1), R １ and R ２ are the same or different and each represents an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group, or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8 carbon atoms, preferably 1 to 5 carbon atoms, and n is an integer of 0 to 2.

[0038] Specific examples of compound (a1) include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyl-methyldiethoxysilane, 3-aminopropyl-methyldimethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, 4-amino-3,3-dimethylbutyltriethoxysilane, and combinations thereof. 3-Aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane are particularly preferred.

[0039] <Unsaturated Carboxylic Acid Alkyl Ester (a2)> In the present invention, the unsaturated carboxylic acid alkyl ester (a2) is at least one selected from the group consisting of branched alkyl esters of unsaturated dicarboxylic acids (a2-1), and branched alkyl esters of unsaturated monocarboxylic acids which may contain a heteroatom or alkyl esters having a cyclic structure (a2-2).

[0040] <Branched Alkyl Ester of Unsaturated Dicarboxylic Acid (a2-1)> The branched alkyl ester of unsaturated dicarboxylic acid (a2-1) is a branched alkyl ester of fumaric acid or maleic acid, and examples thereof include compounds represented by the following formula (2):

[0041] R ４OC(=O)-HC=CH-C(=O)-OR ５ (2)

[0042] In formula (2), R ４ and R ５ are the same or different and are branched alkyl groups having 1 to 8 carbon atoms.

[0043] As used herein, the term "branched alkyl group" refers to an alkyl group in which the carbon skeleton constituting the alkyl group is branched. Examples of the branched alkyl group include an i-propyl group, a 1-methylpropyl group, an i-butyl group, a t-butyl group, an i-pentyl group, a t-pentyl group, and a 2-ethylhexyl group.

[0044] <Branched Alkyl Ester or Cyclic Alkyl Ester (a2-2) of Unsaturated Monocarboxylic Acid Which May Contain a Heteroatom> In the present invention, the branched alkyl ester or cyclic alkyl ester (a2-2) of unsaturated monocarboxylic acid which may contain a heteroatom is specifically a compound represented by the following formula (3): ２ C=CH-C(=O)-OR ６ (3)

[0045] In formula (3), R ６ represents a group in which a heteroatom, such as an oxygen atom, nitrogen atom, or sulfur atom, is contained in the molecule of a branched alkyl group having 3 to 18 carbon atoms or an alkyl group having a cyclic structure, or an alkyl group having 1 to 18 carbon atoms and a branched or cyclic structure.

[0046] Examples of the branched alkyl group include an i-propyl group, a 1-methylpropyl group, an i-butyl group, a t-butyl group, an i-pentyl group, a t-pentyl group, a 2-ethylhexyl group, an i-nonyl group, an i-decyl group, an i-tridecyl group, and an i-stearyl group. Examples of the alkyl group having a cyclic structure include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a trimethylcyclohexyl group, an isobornyl group, a dicyclopentanyl group, and an adamantyl group. A group containing a heteroatom, such as an oxygen atom, a nitrogen atom, or a sulfur atom, in the alkyl or arylalkyl molecule refers to a group in which a portion of the carbon atoms (typically carbon atoms other than terminal portions) contained in the alkyl or arylalkyl group (typically carbon atoms in the alkyl group portion) are substituted with a heteroatom or a group consisting of a heteroatom and hydrogen (e.g., -O-, -N=, -NH-, -S-, etc.). For example, a dimethylaminoethyl group corresponds to a group in which the carbon atom at position 3 of an isopentyl group is substituted with -N=. The substitution of the carbon atom with a heteroatom (e.g., oxygen atom, nitrogen atom, sulfur atom, etc.) or a group consisting of a heteroatom and hydrogen can occur at one or more positions (e.g., 1 to 3 positions, 1 to 2 positions, or 1 position). The number of carbon atoms in a "group containing a heteroatom in an alkyl or arylalkyl group" refers to the number of carbon atoms in a structure in which some of the carbon atoms in the alkyl or arylalkyl group are substituted with a heteroatom or a group consisting of a heteroatom and hydrogen (e.g., a dimethylaminoethyl group has 4 carbon atoms). Examples of groups containing a heteroatom in an alkyl group molecule include a tetrahydrofurfuryl group, a phenoxyethyl group, and a dimethylaminoethyl group.

[0047] <Saturated Carboxylic Acid Alkyl Ester (a3)> In the present invention, examples of the saturated carboxylic acid alkyl ester (a3) ​​include compounds represented by the following formula (4): ７ -C(=O)-OR ８ (4)

[0048] In formula (4), R ７ and R８ are the same or different and represent an alkyl group having 1 to 18 carbon atoms or a group having 1 to 18 carbon atoms and containing a heteroatom such as an oxygen atom, nitrogen atom or sulfur atom in the alkyl molecule. ７ and R ８ or a group containing a hetero atom, such as an oxygen atom, a nitrogen atom or a sulfur atom in the alkyl group molecule does not have an unsaturated group.

[0049] Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a 1-methylpropyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, an i-pentyl group, a t-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, an i-nonyl group, an n-decyl group, an i-decyl group, an n-undecyl group, an n-dodecyl group, an i-tridecyl group, an i-stearyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a trimethylcyclohexyl group, an isobornyl group, an adamantyl group, a 2,2,4-trimethylpentyl group, etc. Examples of groups containing a heteroatom in the alkyl or arylalkyl molecule include a tetrahydrofurfuryl group, a phenoxyethyl group, a dimethylaminoethyl group, etc.

[0050] Specific examples of saturated carboxylic acid alkyl esters (a3) ​​include methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, n-pentyl acetate, i-pentyl acetate, cyclohexyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, 1-methylpentyl acetate (also known as sec-hexyl acetate), 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 3-methoxybutyl acetate, 3-ethoxybutyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, i-propyl propionate, n-butyl propionate, i-butyl propionate, n-pentyl propionate, i-pentyl propionate, and methyl butyrate. butyl, ethyl butyrate, n-propyl butyrate, i-propyl butyrate, n-butyl butyrate, i-butyl butyrate, t-butyl butyrate, methyl valerate, ethyl valerate, methyl octanoate, methyl laurate, methoxypropyl acetate, ethyl 3-ethoxypropionate, butyl glycol acetate, butyl diglycol acetate, methyl i-valerate, ethyl i-valerate, methyl 3,3,5-trimethylhexanoate, methyl i-butyrate, ethyl i-butyrate, i-butyl i-butyrate, n-butyl i-butyrate, t-butyl i-butyrate, methyl 2-ethylhexanoate, methyl pivalate, ethyl 2-hydroxy-2-methylpropionate, methyl neodecanoate, and combinations thereof.

[0051] The saturated carboxylic acid alkyl ester (a3) ​​is preferably a linear alkyl ester of a carboxylic acid having two or more hydrogen atoms at the α-position, or a branched alkyl ester of a carboxylic acid having two hydrogen atoms at the α-position. Compared with a branched alkyl ester having only one hydrogen atom at the α-position, a carboxylic acid alkyl ester of such a structure is less affected by steric hindrance at the α-position, and is therefore preferred because it allows the reaction with the alkoxysilane (a1) to proceed at an appropriate rate.

[0052] Specific examples of alkyl esters of linear carboxylic acids having two or more hydrogen atoms at the α-position include methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, n-pentyl acetate, i-pentyl acetate, cyclohexyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, 1-methylpentyl acetate (also known as sec-hexyl acetate), 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 3-methoxybutyl acetate, 3-ethoxybutyl acetate, methyl propionate, and ethyl propionate. Examples of suitable esters include butyl propionate, n-propyl propionate, i-propyl propionate, n-butyl propionate, i-butyl propionate, n-pentyl propionate, i-pentyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, i-propyl butyrate, n-butyl butyrate, i-butyl butyrate, t-butyl butyrate, methyl valerate, ethyl valerate, methyl octanoate, methyl laurate, methoxypropyl acetate, ethyl 3-ethoxypropionate, butyl glycol acetate, butyl diglycol acetate, and combinations thereof.

[0053] Specific examples of alkyl esters of branched carboxylic acids having two hydrogen atoms at the α-position include methyl i-valerate, ethyl i-valerate, methyl 3,3,5-trimethylhexanoate, and combinations thereof.

[0054] <Polyisocyanate (a4)> In the present invention, the polyisocyanate (a4) is a compound having at least two isocyanate groups in one molecule. Examples of the polyisocyanate (a4) include aliphatic polyisocyanates, alicyclic polyisocyanates, araliphatic polyisocyanates, aromatic polyisocyanates, derivatives thereof, and combinations thereof.

[0055] Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, dimer acid diisocyanate, methyl 2,6-diisocyanatohexanoate (common name: lysine diisocyanate), aliphatic diisocyanates such as 2-isocyanatoethyl 2,6-diisocyanatohexanoate, 1,6-diisocyanato-3-isocyanatomethylhexane, 1,4,8-triisocyanatooctane, 1,6,11-triisocyanatoundecane, 1,8-diisocyanato-4-isocyanatomethyloctane, 1,3,6-triisocyanatohexane, and 2,5,7-trimethyl-1,8-diisocyanato-5-isocyanatomethyloctane.

[0056] Examples of the alicyclic polyisocyanate include 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (common name: isophorone diisocyanate), 4-methyl-1,3-cyclohexylene diisocyanate (common name: hydrogenated TDI), 2-methyl-1,3-cyclohexylene diisocyanate, alicyclic diisocyanates such as 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane (common name: hydrogenated xylylene diisocyanate) or a mixture thereof, methylenebis(4,1-cyclohexanediyl)diisocyanate (common name: hydrogenated MDI), and norbornane diisocyanate; 1,3,5-triisocyanatocyclohexane, 1,3,5-trimethylisocyanatocyclohexane, 2-(3-isocyanatopropyl)- 2,5-di(isocyanatomethyl)-bicyclo(2.2.1)heptane, 2-(3-isocyanatopropyl)-2,6-di(isocyanatomethyl)-bicyclo(2.2.1)heptane, 3-(3-isocyanatopropyl)-2,5-di(isocyanatomethyl)-bicyclo(2.2.1)heptane, 5-(2-isocyanatoethyl)-2-isocyanatomethyl-3-(3-isocyanatopropyl)-bicyclo(2.2.1)heptane, 6-(2-isocyanatoethyl)- alicyclic triisocyanates such as 2-isocyanatoethyl-3-(3-isocyanatopropyl)-bicyclo(2.2.1)heptane, 5-(2-isocyanatoethyl)-2-isocyanatomethyl-2-(3-isocyanatopropyl)-bicyclo(2.2.1)heptane, and 6-(2-isocyanatoethyl)-2-isocyanatomethyl-2-(3-isocyanatopropyl)-bicyclo(2.2.1)heptane.

[0057] Examples of the araliphatic polyisocyanate include araliphatic diisocyanates such as methylenebis(4,1-phenylene)diisocyanate (common name: MDI), 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, ω,ω'-diisocyanato-1,4-diethylbenzene, 1,3- or 1,4-bis(1-isocyanato-1-methylethyl)benzene (common name: tetramethylxylylene diisocyanate) or a mixture thereof; and araliphatic triisocyanates such as 1,3,5-triisocyanatomethylbenzene.

[0058] Examples of the aromatic polyisocyanate include aromatic diisocyanates such as m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 2,4-tolylene diisocyanate (common name: 2,4-TDI) or 2,6-tolylene diisocyanate (common name: 2,6-TDI) or mixtures thereof, 4,4'-toluidine diisocyanate, and 4,4'-diphenyl ether diisocyanate; aromatic triisocyanates such as triphenylmethane-4,4',4''-triisocyanate, 1,3,5-triisocyanatobenzene, and 2,4,6-triisocyanatotoluene; and aromatic tetraisocyanates such as 4,4'-diphenylmethane-2,2',5,5'-tetraisocyanate.

[0059] Furthermore, examples of the polyisocyanate derivatives include dimers, trimers, biurets, allophanates, uretdione, uretoimine, isocyanurate, oxadiazinetrione, etc. of the above-mentioned polyisocyanates, as well as polymethylene polyphenyl polyisocyanates (crude MDI, polymeric MDI), crude TDI, etc. Furthermore, the polyisocyanate derivatives may be modified with polyol compounds and / or monool compounds including known diols or triols in order to adjust the number of functional groups of the isocyanate groups or to adjust compatibility or physical properties.

[0060] The polyisocyanate (a4) is preferably a polyisocyanate derivative having an isocyanate group content of 10% by mass or more, 12% by mass or more, 30% by mass or less, or 25% by mass or less.

[0061] Here, the isocyanate group content of the polyisocyanate (a4) is the amount of isocyanate groups in the polyisocyanate (a4) expressed as a mass fraction. The isocyanate group content can be measured according to a catalog value or the method for determining isocyanate group content in JIS K1603-1.

[0062] <Modified Polyisocyanate and Production Method Thereof> In the present invention, in a first embodiment, the modified polyisocyanate is a reaction product (referred to as modified polyisocyanate (X)) using as raw materials components containing an alkoxysilane (a1) having a primary amino group, an unsaturated carboxylic acid alkyl ester (a2), and a polyisocyanate (a4), and is preferably a modified polyisocyanate in which a secondary amino group of an N-position-modified alkoxysilane represented by formula (5) or (6), in which the primary amino group of the alkoxysilane (a1) is added to the unsaturated carbon-carbon bond of the unsaturated carboxylic acid alkyl ester (a2), is adducted to the isocyanate group of the polyisocyanate (a4):

[0063]

[0064] In formula (5), R １ and R ２ are the same or different and each represents an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group, or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8, preferably 1 to 5, carbon atoms; R ４ and R ５ are the same or different and each represents a branched alkyl group having 1 to 8 carbon atoms; and n is an integer of 0 to 2.

[0065]

[0066] In formula (6), R １ and R ２are the same or different and each represents an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group, or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8, preferably 1 to 5, carbon atoms; R ６ is a group obtained by incorporating a heteroatom into the molecule of an alkyl group having a branched or cyclic structure and having 1 to 18 carbon atoms, or an alkyl group or arylalkyl group having a branched or cyclic structure and having 1 to 18 carbon atoms, and n is an integer of 0 to 2.

[0067] Alternatively, in a second embodiment, the reaction product (referred to as modified polyisocyanate (Y)) is made from raw materials containing an alkoxysilane (a1) having a primary amino group, a saturated carboxylic acid alkyl ester (a3), and a polyisocyanate (a4), and is preferably a modified polyisocyanate in which an N-position modified alkoxysilane obtained by reacting an alkoxysilane (a1) with a saturated carboxylic acid alkyl ester (a3) ​​is an N-position acyl modified alkoxysilane represented by the following formula (7), in which the secondary amide group is adducted to the isocyanate group of the polyisocyanate (a4):

[0068]

[0069] In formula (7), R １ and R ２ are the same or different and each represents an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group, or heteroaryl group having 1 to 18 carbon atoms; n is an integer of 0 to 2; R 3 is a linear or branched alkylene group having 1 to 8, preferably 1 to 5, carbon atoms; R ７ represents an alkyl group having 1 to 18 carbon atoms and having no unsaturated group, or a group having 1 to 18 carbon atoms and having a heteroatom in the alkyl molecule and having no unsaturated group.

[0070] The method for producing the modified polyisocyanate (X) or (Y) may be a method of simultaneously reacting an alkoxysilane (a1) having a primary amino group, an unsaturated carboxylic acid alkyl ester (a2) or a saturated carboxylic acid alkyl ester (a3), and a polyisocyanate (a4). However, a preferred method is a method of previously reacting an alkoxysilane (a1) with an unsaturated carboxylic acid alkyl ester (a2) or a saturated carboxylic acid alkyl ester (a3) ​​to obtain an N-position-modified alkoxysilane having a secondary amino group or a secondary amide group, and then reacting this with a polyisocyanate (a4).

[0071] Method for producing modified polyisocyanate (X): In the modified polyisocyanate (X), the blending ratio of the alkoxysilane (a1) having a primary amino group to the unsaturated carboxylic acid alkyl ester (a2) is preferably within a range of, for example, 0.7 mol or more, 0.85 mol or more, 1.5 mol or less, and 1.25 mol or less of the unsaturated carboxylic acid alkyl ester (a2) per 1 mol of the alkoxysilane (a1) having a primary amino group.

[0072] Furthermore, when the unsaturated carboxylic acid alkyl ester (a2) in the modified polyisocyanate (X) is a branched alkyl ester of an unsaturated dicarboxylic acid (a2-1), the reaction ratio of the N-position-modified alkoxysilane having a secondary amino group to the polyisocyanate (a4) is preferably adjusted so that the number of secondary amino groups is 40 moles or less, preferably 3 moles or more and 35 moles or less, per 100 moles of isocyanate groups, in terms of the adhesion of the coating to iron and non-ferrous metals, curability, and storage stability of the modified polyisocyanate.

[0073] In the modified polyisocyanate (X), when the unsaturated carboxylic acid alkyl ester (a2) is a branched alkyl ester or an alkyl ester (a2-2) having a cyclic structure which may contain a heteroatom of an unsaturated monocarboxylic acid, the reaction of the alkoxysilane (a1) having a primary amino group with the unsaturated carboxylic acid alkyl ester (a2) may produce a by-product, in addition to the N-position-modified alkoxysilane represented by formula (6), a compound represented by formula (8) below, and accordingly, a mixture containing the N-position-modified alkoxysilane mixed with unreacted alkoxysilane (a1) having a primary amino group may be obtained.

[0074]

[0075] In formula (8), R １ and R ２ are the same or different and each represents an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group, or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8, preferably 1 to 5, carbon atoms; R ６ is a group obtained by incorporating a heteroatom into the molecule of an alkyl group having a branched or cyclic structure and having 1 to 18 carbon atoms, or an alkyl group or arylalkyl group having a branched or cyclic structure and having 1 to 18 carbon atoms, and n is an integer of 0 to 2.

[0076] Therefore, in this case, the reaction of the N-position-modified alkoxysilane having a secondary amino group with the polyisocyanate (a4) is carried out in the coexistence of the unreacted alkoxysilane (a1) having a primary amino group and the by-product tertiary amino group-containing compound represented by formula (8).

[0077] In the modified polyisocyanate (X), when the unsaturated carboxylic acid alkyl ester (a2) is a branched alkyl ester or an alkyl ester (a2-2) having a cyclic structure which may contain a heteroatom of an unsaturated monocarboxylic acid, the reaction ratio of the mixture containing the N-position-modified alkoxysilane with the polyisocyanate (a4) is preferably adjusted so that the total number of moles of primary amino groups and secondary amino groups per 100 moles of isocyanate groups is 40 moles or less, preferably 3 moles or more and 35 moles or less, in terms of the adhesion of the coating to iron and non-ferrous metals, curability, and storage stability of the modified polyisocyanate (X).

[0078] The reaction to obtain an N-position modified alkoxysilane from an alkoxysilane (a1) having a primary amino group and an unsaturated carboxylic acid alkyl ester (a2) can be carried out at 0 to 110°C, with air blown in as needed. The reaction time varies depending on the temperature, but is usually between 1 hour and 2 weeks. The reaction may be carried out by adding the unsaturated carboxylic acid alkyl ester (a2) to the alkoxysilane (a1) having a primary amino group, or by adding the alkoxysilane (a1) having a primary amino group to the unsaturated carboxylic acid alkyl ester (a2). To prevent polymerization of the unsaturated carboxylic acid alkyl ester (a2), a small amount of a known aromatic polymerization inhibitor such as methoquinone or a nitroso compound such as N-oxyl may be added, if necessary.

[0079] The reaction of the polyisocyanate (a4) with an N-position-modified alkoxysilane obtained from an alkoxysilane (a1) having a primary amino group and an unsaturated carboxylic acid alkyl ester (a2) can be carried out under known and conventional reaction conditions without any particular limitations. Specifically, the N-position-modified alkylalkoxysilane and the polyisocyanate (a4) can be stirred and mixed together at 0 to 80°C for 0.1 to 5 hours, either all at once or while being added dropwise. Depending on the desired performance, the mixing can be performed by adding the N-position-modified alkoxysilane to the polyisocyanate (a4), or by adding the polyisocyanate (a4) to the N-position-modified alkoxysilane. This reaction can also use a Lewis acid catalyst, a basic catalyst, or an organic solvent, as needed. The resulting mixture containing the reaction product can be aged at 0 to 80°C for 1 day to 1 month, as needed.

[0080] Method for producing modified polyisocyanate (Y): In the reaction of an alkoxysilane (a1) having a primary amino group with a saturated carboxylic acid alkyl ester (a3) ​​to obtain an N-position modified alkoxysilane, the blending ratio of the alkoxysilane (a1) having a primary amino group to the saturated carboxylic acid alkyl ester (a3) ​​is preferably within a range of, for example, 0.7 mol or more, 0.85 mol or more, 1.5 mol or less, and 1.25 mol or less of the saturated carboxylic acid alkyl ester (a3) ​​per 1 mol of the alkoxysilane (a1) having a primary amino group.

[0081] The reaction between the alkoxysilane (a1) having a primary amino group and the saturated carboxylic acid alkyl ester (a3) ​​may be carried out by heating to 100 to 250°C, or by adding a basic catalyst or Lewis acid catalyst and carrying out the reaction at 0 to 160°C. Adding a catalyst is preferable because a basic catalyst is more effective even in small amounts. Either reaction condition may be carried out under pressurized conditions as needed. This reaction may be carried out in the presence of a known antioxidant such as methoquinone to suppress coloration. The reaction time varies depending on the temperature and other conditions, but is typically about 1 hour to 3 days. It is then preferable to mix the components all at once or dropwise, and then, if necessary, combine this with aging.

[0082] When a basic catalyst or Lewis acid catalyst is added, it may be added after mixing the alkoxysilane (a1) having a primary amino group with the saturated carboxylic acid alkyl ester (a3), or it may be added in advance to the alkoxysilane (a1) having a primary amino group and then mixed with the saturated carboxylic acid alkyl ester (a3), or it may be added in advance to the saturated carboxylic acid alkyl ester (a3) ​​and then mixed with the alkoxysilane (a1) having a primary amino group.

[0083] In the present invention, the modified polyisocyanate (Y) is preferably produced by the following steps: (1) reacting an alkoxysilane (a1) having a primary amino group with a saturated carboxylic acid alkyl ester (a3) ​​in the presence of a basic catalyst; (2) adding an acidic compound, if necessary, to a mixture containing the reaction product obtained in the step (1); (3) removing a part or all of the alcohol produced as a by-product to prepare an intermediate containing an N-acyl-modified product represented by the following formula (7); and (4) reacting the intermediate with a polyisocyanate (a4).

[0084]

[0085] In formula (7), R １ and R ２ are the same or different and each represents an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group, or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8 carbon atoms, preferably 1 to 5 carbon atoms, n is an integer of 0 to 2, and R ７ represents an alkyl group having 1 to 18 carbon atoms and having no unsaturated group, or a group having 1 to 18 carbon atoms and containing a heteroatom such as an oxygen atom, nitrogen atom or sulfur atom in the alkyl molecule, and having no unsaturated group.

[0086] By using such a production method, a modified polyisocyanate having excellent adhesion to non-ferrous metals can be easily obtained.

[0087] Examples of the basic catalyst added in step (1) include metal hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide, and calcium hydroxide; carbonates such as sodium carbonate and potassium carbonate; hydrogen carbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate; metal alkoxides such as sodium methoxide and potassium t-butoxide; organic metals such as butyllithium; potassium silanolate; ammonia gas, aqueous ammonia, methylamine, trimethylamine, triethylamine, 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 1,5-diazabicyclo[4.3.0]-5-nonene (DBN), and other nitrogen compounds. These basic catalysts may be used without dissolving them in an organic solvent, or may be added by dissolving them in advance in a solvent such as water; alcohols such as methanol and ethanol; esters such as methyl acetate and ethyl acetate; or ethers such as tetrahydrofuran, cyclopentyl methyl ether, and trimethyl orthoacetate.

[0088] Examples of the acidic compound added in step (2) include inorganic Bronsted acids such as hydrogen chloride, hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid; organic Bronsted acids such as carboxylic acids, alkylsulfonic acids, arylsulfonic acids, monoalkylphosphoric acids, dialkylphosphoric acids, and arylphosphonic acids; and acyl chlorides such as acetyl chloride and benzoyl chloride. These acidic compounds may be used without dissolving them in an organic solvent, or may be added by dissolving them in advance in a solvent such as water; alcohols such as methanol and ethanol; esters such as methyl acetate and ethyl acetate; or ethers such as tetrahydrofuran, cyclopentyl methyl ether, and trimethyl orthoacetate. The addition of the acidic compound is preferably carried out before step (3), but may also be carried out during step (3).

[0089] In step (3), heating and, if necessary, reducing the pressure removes part or all of the alcohol by-produced in step (1), as well as, if necessary, the alkoxysilane (a1) having a primary amino group and / or saturated carboxylic acid alkyl ester (a3) ​​remaining as unreacted raw materials. The removal in the present invention may be carried out by either of two methods: concentration or distillation. Concentration is a method of removing compounds to be removed from the system while leaving desired compounds in the system. In contrast, distillation is a method of extracting desired compounds from the system. While distillation produces a highly purified N-acyl modified product, the process and required equipment are complex, and the energy required is large, resulting in a significant environmental impact. On the other hand, concentration not only contains impurities such as catalyst residues, but also, in some cases, unreacted alkoxysilane (a1) having a primary amino group and saturated carboxylic acid alkyl ester (a3). Therefore, the N-acyl modified product is obtained as a crude N-acyl modified product with a low purity. However, the process and required equipment are simple, and the energy required is small, resulting in a low environmental impact. From the viewpoint of ease of production, it is more advantageous to remove the components by using a concentration method.

[0090] In the present invention, even if step (3) is carried out by concentration rather than distillation, it is possible to provide a modified polyisocyanate as a coating curing agent with sufficient performance by reaction with polyisocyanate (a4). On the other hand, in order to further improve the corrosion prevention or corrosion resistance of the coating film, the crude N-acyl-modified product obtained by using a carboxylic acid ester having a branched structure and two hydrogen atoms at the α-position as the saturated carboxylic acid alkyl ester (a3) ​​may be purified by distillation as necessary before use. On the other hand, the crude N-acyl-modified product obtained by using a carboxylic acid ester having a linear structure and two or more hydrogen atoms at the α-position as the saturated carboxylic acid alkyl ester (a3) ​​is more preferred from the viewpoint of ease of production, since it is easy to obtain a coating film that exhibits extremely high corrosion prevention and weather resistance even when used without purification by distillation.

[0091] Step (4) may be carried out at 40 to 200°C without adding a catalyst, or at 20 to 140°C with the addition of a basic catalyst or Lewis acid catalyst. Adding a catalyst in step (4) is more preferable because a small amount of Lewis acid catalyst is likely to be effective. Known Lewis acid catalysts can be used, including tin compounds such as dialkyltin dicarboxylate, monoalkyltin tricarboxylate, dialkyltin oxide, and tin dicarboxylate; zinc compounds such as zinc dicarboxylate and zinc di(acetylacetonate); zirconium compounds such as zirconium tetraalkoxide, dialkoxyzirconium di(acetylacetonate), and zirconium tetra(acetylacetonate); titanium compounds such as titanium tetraalkoxide, dialkoxytitanium di(acetylacetonate), and titanium tetra(acetylacetonate); aluminum compounds such as aluminum tri(acetylacetonate); and bismuth compounds such as bismuth tricarboxylate.

[0092] In each of steps (1), (2), (3) and (4), a filtration operation may be added as necessary, and a known filtering material can be used for the filtration operation.

[0093] In the production of the modified polyisocyanate (Y), the reaction ratio of the purified N-position-modified alkoxysilane or crude N-position-modified alkoxysilane obtained from the alkoxysilane (a1) having a primary amino group and the saturated carboxylic acid alkyl ester (a3) ​​with the polyisocyanate (a4) is preferably adjusted so that the total number of moles of secondary amide groups and primary amino groups is 40 moles or less, preferably 3 moles or more and 35 moles or less, per 100 moles of isocyanate groups.

[0094] As described above, the modified polyisocyanate of the present invention is preferably produced via an N-position-modified alkoxysilane having a secondary amino group or a secondary amide group, such as modified polyisocyanate (X) or modified polyisocyanate (Y), which is effective in improving compatibility with the active hydrogen group-containing compound and organic solvents described below. Furthermore, in order to enhance stability, the modified polyisocyanate of the present invention may be produced by reacting the N-position-modified alkoxysilane having a secondary amino group or a secondary amide group with a polyisocyanate, and then subsequently adding the acidic compound described above, if necessary.

[0095] In obtaining the N-position modified alkoxysilane, in order to adjust the performance of the coating film obtained by using a modified polyisocyanate as a curing agent, the alkoxysilane (a1) having a primary amino group may be reacted with an alkoxysilane having both a primary amino group and a secondary amino group, such as 3-(2-aminoethylamino)propyltrialkoxysilane, in combination with the unsaturated carboxylic acid alkyl ester (a2) or the saturated carboxylic acid alkyl ester (a3).

[0096] The amount of isocyanate groups in the modified polyisocyanate of the present invention is preferably, for example, in the range of 1.0 mmol or more, 2.0 mmol or more, per gram of the nonvolatile content of the modified polyisocyanate, from the viewpoints of the curability of the coating film, adhesion to non-ferrous metals, weather resistance, and corrosion resistance. The upper limit of the amount of isocyanate groups in the modified polyisocyanate is not limited, but can be designed to be, for example, in the range of 5.5 mmol or less, 5.0 mmol or less, per gram of the nonvolatile content of the modified polyisocyanate.

[0097] The amount of isocyanate groups in the modified polyisocyanate can be determined, for example, by adding 10 ml of a 0.1 mol / L dibutylamine solution to 0.1 g of a sample to react with the NCO groups, and then titrating the remaining dibutylamine with an aqueous hydrochloric acid solution using bromophenol blue as a titration indicator.

[0098] In this specification, the nonvolatile content is the residue remaining after removing volatile components such as organic solvents, and can be measured in accordance with JIS K 5601 1-2 (heating temperature: 125° C., heating time: 60 minutes).

[0099] In the present invention, an organic solvent can be used as a reaction solvent for producing the modified polyisocyanate or as a dilution solvent for diluting the modified polyisocyanate to a viscosity suitable for use as a coating material curing agent. Examples of the organic solvent include aliphatic solvents such as n-butane, n-hexane, n-heptane, n-octane, cyclopentane, cyclohexane, and cyclobutane; aromatic solvents such as toluene and xylene; ketone solvents such as methyl i-butyl ketone; ether solvents such as n-butyl ether, dioxane, and cyclopentyl methyl ether; ester solvents such as ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, and butyl carbitol acetate; ketone solvents such as methyl ethyl ketone, methyl i-butyl ketone, and di-i-butyl ketone; and combinations thereof. In addition, organic solvents with weak dissolving power, commonly referred to as weak solvents in the paint industry, such as gasoline, kerosene, coal tar naphtha (including solvent naphtha), petroleum ether, petroleum naphtha, petroleum benzine, turpentine oil, and mineral spirits (including mineral thinner, petroleum spirits, white spirits, and mineral turpentine), can also be used satisfactorily.

[0100] In the present invention, the organic solvent may be contained in either the base resin or the curing agent. However, the amount of the organic solvent contained in the curing agent is preferably 200 parts by mass or less, preferably 10 parts by mass or more and 100 parts by mass or less, based on 100 parts by mass of the nonvolatile content of the modified polyisocyanate. In a typical embodiment, the modified polyisocyanate of the present invention is used as a curing agent for a coating. Accordingly, in one embodiment, the present invention provides a curing agent containing the modified polyisocyanate. In such an embodiment, the curing agent of the present invention is preferably used in combination with an active hydrogen-containing compound. Furthermore, in the present invention, the modified polyisocyanate may be used alone as a curing agent, or a curing agent composition may be used that further contains the above-mentioned solvent, catalyst, UV absorber, light stabilizer, viscosity modifier, surface modifier, dehydrating agent, etc. in addition to the modified polyisocyanate. These components other than the modified polyisocyanate may be used alone or in combination of two or more. In an embodiment of the curing agent composition, the content of the modified polyisocyanate in the composition is not limited, and can be set within a range of, for example, 30% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, 99% by mass or more, etc.

[0101] <Active Hydrogen Group-Containing Compound> In the present invention, the active hydrogen group-containing compound is a compound used as a binder component together with the modified polyisocyanate. It is not particularly limited as long as it has an active hydrogen group, and may be a compound known and commonly used in the coatings field. Here, the active hydrogen group refers to a group capable of reacting with the isocyanate group of the modified polyisocyanate, such as a hydroxy group, a primary or secondary amino group, or a thiol group. Specific examples of the active hydrogen group-containing compound include acrylic polyols, polyester polyols, polyether polyols, polycarbonate polyols, epoxy polyols, polyol compounds such as dihydroxyalkanes, trihydroxyalkanes, and dihydroxycycloalkanes; acrylic resins with pendant amino groups, polyallylamine, polyether polyamines, polylysine, and polyvinylamines; polymers having multiple secondary amino groups with aspartic acid ester structures; and polyamino compounds such as diaminoalkanes, diaminocycloalkanes, dialkylene triamines, trialkylene tetraamines, and bisaspartic acid ester derivatives. These compounds may be used alone or in combination.

[0102] Among these, the active hydrogen group-containing compound preferably contains an acrylic polyol and / or a bisaspartic acid ester derivative from the viewpoints of improving the weather resistance of the coating film to be formed, improving compatibility in the paint, increasing the nonvolatile content of the paint, controlling the reaction rate with the isocyanate group, etc. Furthermore, in order to adjust the flexibility of the coating film, etc., a polyester polyol or a polyether polyol may be used in combination, if necessary.

[0103] The acrylic polyol may be produced, for example, by copolymerizing a hydroxyl group-containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer (a polymerizable unsaturated monomer other than a hydroxyl group-containing polymerizable unsaturated monomer), or a commercially available product may be used.

[0104] The hydroxyl group-containing polymerizable unsaturated monomer is a compound having one or more hydroxyl groups and one or more polymerizable unsaturated groups per molecule. Examples of the hydroxyl group-containing polymerizable unsaturated monomer include monoesters of (meth)acrylic acid with dihydric alcohols having 2 to 8 carbon atoms, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; ε-caprolactone-modified monoesters of (meth)acrylic acid with dihydric alcohols having 2 to 8 carbon atoms; adducts of (meth)acrylic acid with epoxy group-containing compounds (e.g., "Cardura E10P" (trade name, neodecanoic acid glycidyl ester, manufactured by Hexion); N-hydroxymethyl (meth)acrylamide; allyl alcohol; and (meth)acrylates having a polyoxyethylene chain with a hydroxyl group at the molecular terminal.

[0105] Examples of other polymerizable unsaturated monomers copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer include the following monomers (1) to (7). These polymerizable unsaturated monomers can be used alone or in combination of two or more.

[0106] (1) Acid Group-Containing Polymerizable Unsaturated Monomer The acid group-containing polymerizable unsaturated monomer is a compound having one or more acid groups and one or more polymerizable unsaturated groups per molecule. Examples of such monomers include carboxyl group-containing monomers such as (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, and maleic anhydride; sulfonic acid group-containing monomers such as vinyl sulfonic acid and 2-sulfoethyl (meth)acrylate; and acidic phosphate ester monomers such as 2-(meth)acryloyloxyethyl acid phosphate, 2-(meth)acryloyloxypropyl acid phosphate, 2-(meth)acryloyloxy-3-chloropropyl acid phosphate, and 2-methacryloyloxyethylphenyl phosphoric acid. These monomers may be used alone or in combination.

[0107] (2) Esterification products of acrylic acid or methacrylic acid with monohydric alcohols having 1 to 20 carbon atoms. Specific examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, i-octyl (meth)acrylate, i-myristyl (meth)acrylate, stearyl (meth)acrylate, "isostearyl acrylate" (trade name, manufactured by Osaka Organic Chemical Industry Ltd.), lauryl (meth)acrylate, tridecyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate.

[0108] (3) Alkoxysilyl Group-Containing Polymerizable Unsaturated Monomer The alkoxysilyl group-containing polymerizable unsaturated monomer is a compound having one or more alkoxysilyl groups and one or more polymerizable unsaturated groups per molecule. Examples of the alkoxysilyl group-containing polymerizable unsaturated monomer include vinyltrimethoxysilane, vinyltriethoxysilane, acryloxyethyltrimethoxysilane, methacryloxyethyltrimethoxysilane, acryloxypropyltrimethoxysilane, methacryloxypropyltrimethoxysilane, acryloxypropyltriethoxysilane, methacryloxypropyltriethoxysilane, and vinyltris(β-methoxyethoxy)silane.

[0109] (4) Aromatic vinyl monomers Specific examples include styrene, α-methylstyrene, vinyltoluene, etc. When an aromatic vinyl monomer is used as a constituent component, the blending ratio thereof is preferably within a range of 3% by mass or more, 5% by mass or more, 50% by mass or less, and 40% by mass or less, based on the total amount of the monomer components.

[0110] (5) Glycidyl Group-Containing Polymerizable Unsaturated Monomer The glycidyl group-containing polymerizable unsaturated monomer is a compound having one or more glycidyl groups and one or more polymerizable unsaturated groups in one molecule, and specific examples thereof include glycidyl acrylate and glycidyl methacrylate.

[0111] (6) Polymerizable Unsaturated Group-Containing Nitrogen Atom-Containing Compounds Examples thereof include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-[3-(dimethylamino)propyl](meth)acrylamide, N-butoxymethyl(meth)acrylamide, diacetone(meth)acrylamide, N,N-dimethylaminoethyl(meth)acrylate, vinylpyridine, vinylimidazole, acrylonitrile, and methacrylonitrile.

[0112] (7) Other vinyl compounds Examples include vinyl acetate, vinyl propionate, vinyl chloride, and vinyl versatate.

[0113] In the present invention, the polymerizable unsaturated monomer refers to a monomer having one or more (e.g., 1 to 4) polymerizable unsaturated groups. The polymerizable unsaturated group refers to an unsaturated group that can undergo radical polymerization. Examples of such polymerizable unsaturated groups include a vinyl group, a (meth)acryloyl group, a (meth)acrylamide group, a vinyl ether group, an allyl group, a propenyl group, an i-propenyl group, and a maleimide group.

[0114] In addition, in this specification, "(meth)acrylate" means acrylate or methacrylate. "(meth)acrylic acid" means acrylic acid or methacrylic acid. "(meth)acryloyl" means acryloyl or methacryloyl. "(meth)acrylamide" means acrylamide or methacrylamide.

[0115] From the viewpoint of the weather resistance and corrosion resistance of the coating film to be formed, the acrylic polyol preferably has a hydroxyl value in the range of 5 mgKOH / g or more, 10 mgKOH / g or more, 160 mgKOH / g or less, and 100 mgKOH / g or less, and a weight average molecular weight in the range of 3,000 or more, 10,000 or more, 100,000 or less, and 50,000 or less.

[0116] In this specification, the weight average molecular weight is a value calculated from a chromatogram measured by gel permeation chromatography using the weight average molecular weight of standard polystyrene as a reference. The gel permeation chromatograph used was "HLC8120GPC" (manufactured by Tosoh Corporation). Four columns, "TSKgel G-4000HXL," "TSKgel G-3000HXL," "TSKgel G-2500HXL," and "TSKgel G-2000HXL" (all manufactured by Tosoh Corporation, trade names), were used, and the measurement was performed under the following conditions: mobile phase: tetrahydrofuran, measurement temperature: 40°C, flow rate: 1 mL / min, and detector: RI.

[0117] The bisaspartic acid ester derivative may be any derivative in which a maleic acid diester or a fumaric acid diester is added to an aspartic acid compound having two amino groups, and examples thereof include tetraethyl N,N'-(methylenedi-4,1-cyclohexanediyl)-bisaspartate, tetraethyl N,N'-(methylenebis(2-methyl-di-4,1-cyclohexanediyl))-bisaspartate, and tetraethyl N,N'-(2-methyl-1,5-pentanediyl)-bisaspartate. More specific examples include Desmophen NH 1420, Desmophen NH 1520, Desmophen NH 1220, Desmophen NH 1422, Desmophen NH 1423LF, Desmophen NH 1720, Desmophen NH 1723LF, Desmophen NH 1523LF, and Desmophen NH 1521, all manufactured by Covestro; and Amicure IC-133, Amicure IC-166, and Amicure IC-186 (all trade names) manufactured by Evonik.

[0118] <Coating> The present invention provides a coating comprising an active hydrogen-containing compound and the modified polyisocyanate. The coating of the present invention also encompasses a two-component composition comprising a curing agent containing the modified polyisocyanate and a base component containing the active hydrogen group-containing compound, both stored separately. In a typical embodiment, the coating of the present invention is obtained by mixing a curing agent containing the modified polyisocyanate and a base component containing the active hydrogen group-containing compound, both stored separately, before application. The coating of the present invention can also be referred to as a paint composition. The ratio of the modified polyisocyanate used is preferably such that the equivalent ratio of the modified polyisocyanate is 0.5 or more, 0.7 or more, based on one equivalent of the active hydrogen groups contained in the active hydrogen group-containing compound. The equivalent ratio of the modified polyisocyanate based on one equivalent of the active hydrogen groups contained in the active hydrogen group-containing compound is not limited, but can be designed to be, for example, 2.5 or less, 1.5 or less, etc.

[0119] The coating of the present invention may further contain, as necessary, an anti-rust agent, a catalyst, a coloring pigment, an extender pigment, a luster pigment, a dispersant, an ultraviolet absorber, a light stabilizer, an anti-foaming agent, a viscosity modifier, a surface modifier, a dehydrating agent, an organic solvent, a crosslinking agent, a binder component other than the active hydrogen group-containing compound, and the like.

[0120] Among these, rust inhibitors known in the field of paints can be used as the rust inhibitor, and are commercially available. The rust inhibitor may be an inorganic compound or an organic compound, and its form is not limited, and may include a single compound, a composite compound, a composition using a plurality of these compounds in combination, or a composition obtained by baking a plurality of these compounds. Specific examples include phosphate-based metal compounds such as zinc phosphate, magnesium phosphate, magnesium ammonium phosphate-eutectoid, magnesium monohydrogen phosphate, magnesium dihydrogen phosphate, magnesium phosphate-calcium phosphate-eutectoid, magnesium phosphate-cobalt phosphate, magnesium phosphate-nickel phosphate-eutectoid, calcium phosphate, calcium ammonium phosphate, calcium monohydrogen phosphate, calcium dihydrogen phosphate, calcium fluoride phosphate chloride, aluminum phosphate, and aluminum hydrogen phosphate; phosphite-based metal compounds such as magnesium phosphite, calcium phosphite, magnesium-calcium phosphite-eutectoid, basic zinc phosphite, barium phosphite, manganese phosphite, and calcium hypophosphite; Metal silicates such as calcium silicate, zinc silicate, aluminum silicate, aluminum orthosilicate, aluminum silicate hydroxide, aluminosilicate, borosilicate, beryllosilicate, calcium aluminum silicate, sodium aluminum silicate, beryllium aluminum silicate, sodium silicate, calcium orthosilicate, calcium metasilicate, calcium sodium silicate, zirconium silicate, magnesium orthosilicate, magnesium metasilicate, manganese silicate, and barium silicate; metal ion-exchanged silica compounds such as magnesium ion-exchanged silica and calcium ion-exchanged silica; condensed phosphate metal compounds such as aluminum dihydrogen tripolyphosphate, aluminum dihydrogen triphosphate-magnesium oxide composite, aluminum tripolyphosphate, and aluminum dihydrogen tripolyphosphate-zinc oxide composite; vanadium metal compounds such as vanadium pentoxide, calcium vanadate, magnesium vanadate, ammonium metavanadate, fired product of manganese oxide and vanadium oxide, and fired product of calcium phosphate and vanadium oxide; Molybdic acid-based metal compounds such as aluminum molybdate, calcium molybdate, and aluminum phosphomolybdate; zinc, zinc oxide, and other zinc-based compounds;Examples of suitable inorganic fillers include silica-based compounds such as silica and colloidal silica; composite metal iron oxides such as composite iron oxides of iron oxide and magnesium oxide, composite iron oxides of iron oxide and calcium oxide, and composite iron oxides of iron oxide and zinc oxide; and sulfur-containing organic compounds such as triazole compounds, thiol compounds, thiadiazole compounds, and thiazole compounds.

[0121] When the coating of the present invention contains the above-mentioned rust inhibitor, the amount of the rust inhibitor blended is preferably within a range of 1 part by mass or more, 3 parts by mass or more, 70 parts by mass or less, and 60 parts by mass or less, based on 100 parts by mass of the nonvolatile content of the active hydrogen-containing compound.

[0122] As the catalyst, compounds conventionally known for use in coatings can be used, specifically, organometallic compounds and amine compounds.

[0123] Examples of organometallic compounds include diacetyltin diacetate, diacetyltin dioctoate, dioctyltin diacetate, dioctyltin di(2-ethylhexanoate), dioctyltin dilaurate, dioctyltin dineodecanoate, dioctyltin oxide, dibutyltin diacetate, dibutyltin di(2-ethylhexanoate), dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin oxide, dibutyltin sulfide, dibutyltin fatty acid salts, tin octoate, zinc octoate, zinc naphthenate, zinc fatty acids, bismuth octanoate, bismuth 2-ethylhexanoate, bismuth oleate, bismuth neodecanoate, bismuth versatate, bismuth naphthenate, cobalt naphthenate, calcium octoate, copper naphthenate, and tetra(2-ethylhexyl)titanate.

[0124] Examples of the amine compound include aliphatic amines such as trimethylamine, triethylamine, 2-(dimethylamino)ethyl methacrylate, 1,4-diazabicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]-7-undecene, 1,5-diazabicyclo[4.3.0]-5-nonene, 1-methylpiperidine, and 1-methylpyrrolidine, pyridine, 4-dimethylaminopyridine, 4-(1-piperidyl)pyridine, N-methylimidazole, and N,N-dimethylaniline.

[0125] When the coating of the present invention contains the above-mentioned catalyst, the content of the catalyst is preferably in the range of 0.005 mass % or more, 0.01 mass % or more, 2 mass % or less, and 1 mass % or less, relative to the mass of the non-volatile components of the active hydrogen group-containing compound.

[0126] Examples of color pigments include titanium oxide, zinc white, carbon black, red iron oxide, cadmium red, molybdenum red, chrome yellow, chromium oxide, Prussian blue, cobalt blue, azo pigments, phthalocyanine pigments, quinacridone pigments, isoindoline pigments, threne pigments, and perylene pigments.

[0127] Examples of extender pigments include talc, clay, kaolin, baryta, barium sulfate, barium carbonate, calcium carbonate, and alumina white.

[0128] Examples of the luster pigment include aluminum pigments, mica pigments, mica pigments coated with titanium oxide, and aluminum oxide pigments coated with titanium oxide.

[0129] Examples of the dehydrating agent include compounds that consume water by chemically reacting with water, and compounds that physically adsorb water. Examples of the former include trimethyl orthoformate, triethyl orthoformate, trimethyl orthoacetate, triethyl orthoacetate, toluenesulfonyl isocyanate, vinyltrimethoxysilane, and vinyltriethoxysilane, and examples of the latter include zeolite and molecular sieves.

[0130] <Painting> The modified polyisocyanate of the present invention has excellent adhesion to metal substrates, and therefore coatings containing the same are used for painting metal substrates. Metal substrates include both ferrous and non-ferrous metals. Specific examples include steel, galvanized steel, stainless steel, magnesium alloys, aluminum, and aluminum alloys. These may be surface-treated with a phosphate or chromate treatment, for example. Metal substrates also include metal members constituting existing structures, on whose surfaces old paint films or rust remain.

[0131] The coating of the present invention can be diluted with an organic solvent or the like to a viscosity suitable for application, and applied by methods such as air spray coating, airless spray coating, electrostatic coating, brush coating, roller coating, lysine gun, and all-purpose gun. Drying can be performed at room temperature, but heat drying is also possible. Room temperature, which varies depending on the atmospheric temperature of the environment in which the coating is performed, refers to a temperature at which no temperature manipulation such as forced heating or cooling is performed, while heat drying refers to a temperature at which forced heating is performed using equipment such as a drying oven.

[0132] Because the coating of the present invention has excellent adhesion, it is possible to omit the application of a primer paint before applying the coating. Furthermore, because the coating of the present invention also has excellent weather resistance, it is also possible to omit the application of a topcoat paint after applying the coating. The coating of the present invention can form a protective coating film with excellent corrosion resistance and weather resistance on a metal substrate by itself, allowing for a single-layer finish and being applicable as a one-coat paint. Therefore, the present invention provides a cured product of the above-mentioned coating. This cured product can be used as a protective coating. The present invention also provides a coated article (a coated article comprising a substrate and a cured product of the above-mentioned coating disposed on the substrate) in which the cured product of the above-mentioned coating is formed on a substrate. The coated article is preferably a coated metal material in which the cured product of the above-mentioned coating is formed on a metal substrate.

[0133] The present invention will be further described below with reference to examples. However, the present invention is not limited to these examples. Herein, "parts" and "%" mean "parts by mass" and "% by mass," respectively.

[0134] [Preparation of modified polyisocyanate curing agent solution using alkyl ester of unsaturated dicarboxylic acid] Example 1 179 parts of 3-aminopropyltrimethoxysilane and 0.07 parts of methoquinone were placed in a flask and heated to 80°C. Air was introduced into the solution and stirred while bubbling. 220 parts of di-i-propyl fumarate was added dropwise to the solution over 2 hours, and the solution was then maintained at 80°C for 1 hour and further aged at 50°C for 1 week to obtain 3-(N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane (alkoxysilane N-position modified compound represented by formula (5), where R ２ is a methyl group, R ３ is a propylene group, R ４ and R ５ A mixture of 399 parts containing 95% N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane (a compound in which n is an i-propyl group and n is 0) was obtained. Into a separate flask, 400 parts of mineral spirits, 320 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 550 parts of "Duranate TSA-100" (a hexamethylene diisocyanate-modified isocyanurate polyisocyanate, manufactured by Asahi Kasei Corporation, trade name, isocyanate group content 20.6 wt%) were added and stirred at room temperature. To this mixture, 359 parts of a mixture containing 95% 3-(N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane was added dropwise over 2 hours, and the mixture was then maintained at 60°C for 1 hour and cooled to room temperature to obtain a polyisocyanate curing agent solution (HE-1) with a non-volatile content of 55%. The concentration of isocyanate groups contained in 1 g of the curing agent solution (HE-1) was 1.10 mmol / g (2.02 mmol / g in terms of nonvolatile content).

[0135] Example 2 179 parts of 3-aminopropyltrimethoxysilane and 0.07 parts of methoquinone were placed in a flask and heated to 80°C. Air was introduced into the liquid and stirred while bubbling. 251 parts of di(1-methylpropyl) fumarate was added dropwise to the liquid over 2 hours, and the liquid was then kept at 80°C for 1 hour and further aged at 50°C for 1 week to obtain 3-(N-(1,2-bis(1-methylpropoxycarbonyl)ethyl)amino)propyltrimethoxysilane (alkoxysilane N-position modified compound represented by formula (5), where R ２ is a methyl group, R ３ is a propylene group, R ４ and R ５ A mixture of 430 parts containing 95% 3-(N-(1,2-bis(1-methylpropoxycarbonyl)ethyl)amino)propyltrimethoxysilane) (a compound in which n is a 1-methylpropyl group and n is 0) was obtained. Into a separate flask, 400 parts of mineral spirits, 320 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 550 parts of "Duranate TSA-100" (a hexamethylene diisocyanate-modified isocyanurate polyisocyanate, manufactured by Asahi Kasei Corporation, trade name, isocyanate group content 20.6 wt%) were added and stirred at room temperature. 387 parts of a mixture containing 95% 3-(N-(1,2-bis(1-methylpropoxycarbonyl)ethyl)amino)propyltrimethoxysilane was added dropwise over 2 hours, and the mixture was then maintained at 60°C for 1 hour and cooled to room temperature to obtain a polyisocyanate curing agent solution (HE-2) with a non-volatile content of 55%. The concentration of isocyanate groups contained in 1 g of the curing agent solution (HE-2) was 1.08 mmol / g (1.96 mmol / g in terms of nonvolatile content).

[0136] Example 3 89.5 parts of 3-aminopropyltrimethoxysilane and 0.04 parts of methoquinone were placed in a flask and heated to 80°C. Air was introduced into the liquid and stirred while bubbling. 110 parts of di-i-propyl fumarate was added dropwise to the liquid over 2 hours, and the liquid was then kept at 80°C for 1 hour and further aged at 50°C for 1 week to obtain 3-(N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane (alkoxysilane N-position modified compound represented by formula (5), where R ２ is a methyl group, R ３ is a propylene group, R ４ and R ５A mixture of 199 parts containing 95% N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane (a compound in which n is an i-propyl group and n is 0) was obtained. Into a separate flask, 320 parts of mineral spirits, 256 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 550 parts of "Duranate TSA-100" (a hexamethylene diisocyanate-modified isocyanurate polyisocyanate, manufactured by Asahi Kasei Corporation, trade name, isocyanate group content 20.6 wt%) were placed and stirred at room temperature. To this mixture, 162 parts of a mixture containing 95% 3-(N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane was added dropwise over 2 hours, followed by holding at 60°C for 1 hour and cooling to room temperature to obtain a polyisocyanate curing agent solution (HE-3) with a non-volatile content of 55%. The concentration of isocyanate groups contained in 1 g of the curing agent solution (HE-3) was 1.78 mmol / g (3.26 mmol / g in terms of nonvolatile content).

[0137] Example 4 89.5 parts of 3-aminopropyltrimethoxysilane and 0.04 parts of methoquinone were placed in a flask and heated to 80°C. Air was introduced into the liquid and stirred while bubbling. 110 parts of di-i-propyl fumarate was added dropwise to the liquid over 2 hours, and the liquid was then kept at 80°C for 1 hour and further aged at 50°C for 1 week to obtain 3-(N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane (alkoxysilane N-position modified compound represented by formula (5), where R ２ is a methyl group, R ３ is a propylene group, R ４ and R ５A mixture of 199 parts containing 95% N-(N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane) (a compound in which n is an i-propyl group and n is 0) was obtained. Into a separate flask, 280 parts of mineral spirits, 224 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 550 parts of "Duranate TSA-100" (a hexamethylene diisocyanate-modified isocyanurate polyisocyanate, manufactured by Asahi Kasei Corporation, trade name, isocyanate group content 20.6 wt%) were placed and stirred at room temperature. To this mixture, 108 parts of a mixture containing 95% 3-(N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane was added dropwise over 2 hours, and the mixture was then maintained at 60°C for 1 hour and cooled to room temperature to obtain a polyisocyanate curing agent solution (HE-4) with a non-volatile content of 56%. The concentration of isocyanate groups contained in 1 g of the curing agent solution (HE-4) was 2.09 mmol / g (3.72 mmol / g in terms of nonvolatile content).

[0138] Example 5 221 parts of 3-aminopropyltriethoxysilane and 0.07 parts of methoquinone were placed in a flask and heated to 80°C. Air was introduced into the liquid and stirred while bubbling. 220 parts of di-i-propyl fumarate was added dropwise to the mixture over 2 hours, and the mixture was then maintained at 80°C for 1 hour and further aged at 50°C for 1 week to obtain 3-(N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltriethoxysilane (alkoxysilane N-position modified compound represented by formula (5), where R ２ is an ethyl group, R ３ is a propylene group, R ４ and R ５A mixture of 441 parts containing 95% N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltriethoxysilane (a compound in which n is an i-propyl group and n is 0) was obtained. Into a separate flask, 400 parts of mineral spirits, 320 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 550 parts of "Duranate TSA-100" (a hexamethylene diisocyanate-modified isocyanurate polyisocyanate, manufactured by Asahi Kasei Corporation, trade name, isocyanate group content 20.6 wt%) were placed and stirred at room temperature. To this mixture, 397 parts of a mixture containing 95% 3-(N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltriethoxysilane was added dropwise over 2 hours, followed by holding at 60°C for 1 hour and cooling to room temperature to obtain a polyisocyanate curing agent solution (HE-5) with a non-volatile content of 56%. The concentration of isocyanate groups contained in 1 g of the curing agent solution (HE-5) was 1.08 mmol / g (1.94 mmol / g in terms of nonvolatile content).

[0139] Example 6 179 parts of 3-aminopropyltrimethoxysilane and 0.07 parts of methoquinone were placed in a flask and heated to 80°C. Air was introduced into the liquid and stirred while bubbling. 260 parts of di-i-propyl fumarate was added dropwise to the mixture over 2 hours, and the mixture was then maintained at 80°C for 1 hour and further aged at 50°C for 1 week to obtain 3-(N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane (alkoxysilane N-position modified compound represented by formula (5), where R ２ is a methyl group, R ３ is a propylene group, R ４ and R ５A mixture of 439 parts containing 86% of 3-(N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane) (a compound in which n is an i-propyl group and n is 0) was obtained. Into a separate flask, 400 parts of mineral spirits, 280 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 550 parts of "Duranate TSA-100" (a hexamethylene diisocyanate-modified isocyanurate polyisocyanate, manufactured by Asahi Kasei Corporation, trade name, isocyanate group content 20.6 wt%) were placed and stirred at room temperature. To this mixture, 394 parts of a mixture containing 86% of 3-(N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane was added dropwise over 2 hours, and the mixture was then maintained at 60°C for 1 hour and cooled to room temperature to obtain a polyisocyanate curing agent solution (HE-6) with a non-volatile content of 55%. The concentration of isocyanate groups contained in 1 g of the curing agent solution (HE-6) was 1.11 mmol / g (2.03 mmol / g in terms of nonvolatile content).

[0140] Example 7 179 parts of 3-aminopropyltrimethoxysilane and 0.07 parts of methoquinone were placed in a flask and heated to 80°C. Air was introduced into the liquid and stirred while bubbling. 180 parts of di-i-propyl fumarate was added dropwise to the mixture over 2 hours, and the mixture was then maintained at 80°C for 1 hour and further aged at 50°C for 1 week to obtain 3-(N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane (alkoxysilane N-position modified compound represented by formula (5), where R ２ is a methyl group, R ３ is a propylene group, R ４ and R ５A mixture of 359 parts containing 99% N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane (a compound in which n is an i-propyl group and n is 0) was obtained. Into a separate flask, 400 parts of mineral spirits, 320 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 550 parts of "Duranate TSA-100" (a hexamethylene diisocyanate-modified isocyanurate polyisocyanate, manufactured by Asahi Kasei Corporation, trade name, isocyanate group content 20.6 wt%) were added and stirred at room temperature. 323 parts of a mixture containing 99% 3-(N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane was added dropwise over 2 hours, and the mixture was then maintained at 60°C for 1 hour and cooled to room temperature to obtain a polyisocyanate curing agent solution (HE-7) with a non-volatile content of 55%. The concentration of isocyanate groups contained in 1 g of the curing agent solution (HE-7) was 1.13 mmol / g (2.06 mmol / g in terms of nonvolatile content).

[0141] Comparative Example 1 179 parts of 3-aminopropyltrimethoxysilane and 0.07 parts of methoquinone were placed in a flask and heated to 80°C. Air was introduced into the liquid and stirred while bubbling. 189 parts of diethyl fumarate was added dropwise to the mixture over 2 hours, and the mixture was then maintained at 80°C for 1 hour and further aged at 50°C for 1 week to obtain 3-(N-(1,2-bis(ethoxycarbonyl)ethyl)amino)propyltrimethoxysilane (in the case of an N-position-modified alkoxysilane represented by formula (5), R ２ is a methyl group, R ３ is a propylene group, R ４ and R ５A mixture containing 368 parts of 95% 3-(N-(1,2-bis(ethoxycarbonyl)ethyl)amino)propyltrimethoxysilane) (a compound in which n is 0 and both correspond to an ethyl group) was obtained. Into a separate flask, 400 parts of mineral spirits, 320 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 550 parts of "Duranate TSA-100" (a hexamethylene diisocyanate-modified isocyanurate-type polyisocyanate, manufactured by Asahi Kasei Corporation, trade name, isocyanate group content 20.6 wt%) were added and stirred at room temperature. To this mixture, 331 parts of a mixture containing 95% 3-(N-(1,2-bis(ethoxycarbonyl)ethyl)amino)propyltrimethoxysilane was added dropwise over 2 hours, and the mixture was then maintained at 60°C for 1 hour and cooled to room temperature to obtain a polyisocyanate curing agent solution (HR-1) modified with a linear alkyl ester of an unsaturated dicarboxylic acid (nonvolatile concentration: 54%). The concentration of isocyanate groups contained in 1 g of the curing agent solution (HR-1) was 1.12 mmol / g (2.08 mmol / g in terms of nonvolatile content).

[0142] Comparative Example 2 179 parts of 3-aminopropyltrimethoxysilane and 0.07 parts of methoquinone were placed in a flask and heated to 80°C. Air was introduced into the liquid and stirred while bubbling. 251 parts of dibutyl maleate was added dropwise to the mixture over 2 hours, and the mixture was then maintained at 80°C for 1 hour and further aged at 50°C for 1 week to obtain 3-(N-(1,2-bis(butoxycarbonyl)ethyl)amino)propyltrimethoxysilane (in the case of an N-position-modified alkoxysilane represented by formula (5), R ２ is a methyl group, R ３ is a propylene group, R ４ and R ５A mixture containing 430 parts of 95% 3-(N-(1,2-bis(butoxycarbonyl)ethyl)amino)propyltrimethoxysilane) (a compound in which n is 0 and both correspond to n-butyl groups) was obtained. Into a separate flask, 400 parts of mineral spirits, 320 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 550 parts of "Duranate TSA-100" (a hexamethylene diisocyanate-modified isocyanurate polyisocyanate, manufactured by Asahi Kasei Corporation, trade name, isocyanate group content 20.6 wt%) were added and stirred at room temperature. To this mixture, 387 parts of a mixture containing 95% 3-(N-(1,2-bis(butoxycarbonyl)ethyl)amino)propyltrimethoxysilane was added dropwise over 2 hours, and the mixture was then maintained at 60°C for 2 hours and cooled to room temperature to obtain a polyisocyanate curing agent solution (HR-2) modified with a linear alkyl ester of an unsaturated dicarboxylic acid (non-volatile content: 55%). The concentration of isocyanate groups contained in 1 g of the curing agent solution (HR-2) was 1.08 mmol / g (1.96 mmol / g in terms of nonvolatile content).

[0143] Comparative Example 3: 400 parts of mineral spirits, 320 parts of "Swasol 1000" (naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.), and 880 parts of "Duranate TSA-100" (hexamethylene diisocyanate-modified isocyanurate polyisocyanate, product name, manufactured by Asahi Kasei Corporation, isocyanate group content 20.6 wt%) were placed in a container and stirred at room temperature to obtain a polyisocyanate curing agent solution (HR-3) (non-volatile content concentration 55%) that was not modified with aminoalkoxysilane and unsaturated carboxylic acid dialkyl ester. The concentration of isocyanate groups contained in 1 g of curing agent solution (HR-3) was 2.70 mmol / g (4.90 mmol / g in terms of non-volatile content).

[0144] Comparative Example 4 179 parts of 3-aminopropyltrimethoxysilane and 0.07 parts of methoquinone were placed in a flask, heated to 80°C, and air was introduced into the liquid to bubble and stir, yielding 179 parts of a mixture. In a separate flask were placed 400 parts of mineral spirits, 180 parts of "Swasol 1000" (naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.), and 550 parts of "Duranate TSA-100" (hexamethylene diisocyanate-modified isocyanurate polyisocyanate, product name, manufactured by Asahi Kasei Corporation, isocyanate group content 20.6 wt%), and the mixture was stirred at room temperature. To this was added dropwise 161 parts of the mixture containing 3-aminopropyltrimethoxysilane over a period of 2 hours, followed by holding at 60°C for 1 hour and cooling to room temperature in an attempt to obtain a polyisocyanate curing agent solution (HR-4) (non-volatile content concentration 54%) that had been modified with aminoalkoxysilane but not modified with unsaturated carboxylic acid dialkyl ester, but the curing agent precipitated, resulting in a non-uniform solution that could not be used as a curing agent solution, so further evaluation was discontinued. The concentration of isocyanate groups contained in 1 g of curing agent solution (HR-4) was 1.39 mmol / g (2.56 mmol / g in terms of non-volatile content).

[0145] Table 1 below shows the composition, blending molar ratio or reaction molar ratio, state and residual NCO rate of each of the curing agent solutions obtained in the Examples and Comparative Examples.

[0146]

[0147] (Note 1) Primary amino group / unsaturated carbon-carbon bond Actual reaction molar ratio: This represents the molar ratio of aminoalkoxysilane added to unsaturated carboxylic acid dialkyl ester. If an excess of unsaturated carboxylic acid dialkyl ester is added, the excess will not undergo the addition reaction and will remain unreacted, resulting in a difference between the reaction ratio and the compounding ratio. (Note 2) Amino group / isocyanate group reaction molar ratio: Here, amino groups represent the total amount of amino groups, i.e., the total amount of primary amino groups derived from alkoxysilane with unreacted amino groups and 1,2-bis(alkoxycarbonyl)ethylamino groups.

[0148] [Evaluation Items] (*) Condition of Curing Agent Solution Each curing agent solution was sealed in a 250 ml glass bottle and evaluated according to the following criteria. In the table, a rank of ∘ was judged as pass, and ranks of × and XX were judged as fail. The condition was visually observed initially (immediately after production) and after one year of sealed storage in a temperature-controlled room at 25°C and 60% humidity. ∘: No abnormalities were observed in the curing agent solution; ×: Either separation into two layers, turbidity, or precipitates were observed in the curing agent solution; XX: Precipitation of the curing agent from the curing agent solution. (*) Residual NCO Rate in Curing Agent Solution The residual NCO rate was calculated using the following formula for the polyisocyanate curing agent solutions obtained in Examples 1 to 7 and Comparative Examples 1 to 4. The higher the value, the better the result. [(Total number of moles of NCO groups contained in the curing agent solution 12 months after its preparation) / (Total number of moles of NCO groups contained in the curing agent solution immediately after its preparation)]×100(%) The storage conditions were 25°C and 60% humidity, and the total number of moles of NCO groups was calculated by adding 10 ml of a 0.1 mol / L dibutylamine solution to 0.1 g of a sample to react the NCO groups, and titrating the remaining dibutylamine with an aqueous hydrochloric acid solution using bromophenol blue as a titration indicator.

[0149] [Preparation of modified polyisocyanate curing agent solution using alkyl ester of unsaturated monocarboxylic acid] Example 8 179 parts of 3-aminopropyltrimethoxysilane, 0.07 parts of methoquinone, and 6 parts of "Swasol 1000" (naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.) were placed in a flask, and air was introduced into the solution to bubble and stir it. 128 parts of i-butyl acrylate was added dropwise to the solution over 2 hours, and the solution was then kept at 50°C for 1 hour. Further, the solution was aged at 50°C for 1 week to obtain 3-(N-(2-(i-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (alkoxysilane N-position-modified represented by formula (6) where R ２ is a methyl group, R ３ is a propylene group, R ６ is an i-butyl group, and n is 0) / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(i-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (in the compound represented by formula (8), R ２ is a methyl group, R３ is a propylene group, R ６ This yielded 313 parts of a mixture containing two amino groups (a compound in which n is an i-butyl group and n is 0) in a molar ratio of 74 / 13 / 13. The total amount of (primary amino groups + secondary amino groups) per gram of the mixture was 2.78 mmol. Into a separate flask were placed 282 parts of mineral spirits, 231 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 500 parts of "Duranate TSA-100" (a hexamethylene diisocyanate-modified isocyanurate polyisocyanate, manufactured by Asahi Kasei Corporation, trade name, isocyanate group content 20.6 wt%), and the mixture was stirred at room temperature. To this was added dropwise 132 parts of a mixture containing 3-(N-(2-(i-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(i-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane in a molar ratio of 74 / 13 / 13 over 2 hours, and the mixture was then maintained at 60°C for 2 hours and cooled to room temperature to obtain a polyisocyanate curing agent solution (HE-8) with a non-volatile content of 55%. The concentration of isocyanate groups contained in the curing agent solution (HE-8) was 1.82 mmol / g (3.31 mmol / g in terms of non-volatile content).

[0150] Example 9 179 parts of 3-aminopropyltrimethoxysilane, 0.07 parts of methoquinone, and 6 parts of "Swasol 1000" (a naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.) were placed in a flask, and air was introduced into the liquid to bubble and stir it. 128 parts of t-butyl acrylate was added dropwise to the liquid over 2 hours, and the mixture was then kept at 50°C for 1 hour. Further, the mixture was aged at 50°C for 1 week to obtain 3-(N-(2-(t-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (an alkoxysilane N-position-modified compound represented by formula (6) in which R ２ is a methyl group, R ３ is a propylene group, R ６ is a t-butyl group, and n is 0) / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(t-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (in the compound represented by formula (8), R ２ is a methyl group, R ３is a propylene group, R ６ This yielded 313 parts of a mixture containing two primary amino groups (a compound in which n is a t-butyl group and n is 0) in a molar ratio of 78 / 11 / 11. The total amount of (primary amino groups + secondary amino groups) per gram of the mixture was 2.84 mmol. Into a separate flask were placed 281 parts of mineral spirits, 230 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 500 parts of "Duranate TSA-100," and the mixture was stirred at room temperature. To this was added dropwise 130 parts of a mixture containing 3-(N-(2-(t-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(t-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane in a molar ratio of 78 / 11 / 11 over 2 hours, and the mixture was then maintained at 60°C for 2 hours and cooled to room temperature to obtain a polyisocyanate curing agent solution (HE-9) with a non-volatile content of 55%. The concentration of isocyanate groups contained in the curing agent solution (HE-9) was 1.83 mmol / g (3.32 mmol / g in terms of non-volatile content).

[0151] Example 10 89.5 parts of 3-aminopropyltrimethoxysilane, 0.04 parts of methoquinone, and 4 parts of "Swasol 1000" (a naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.) were placed in a flask, and air was introduced into the liquid to bubble and stir it. 92 parts of 2-ethylhexyl acrylate was added dropwise to the liquid over 2 hours, and the mixture was then kept at 50°C for 1 hour. Further, the mixture was aged at 50°C for 1 week to obtain 3-(N-(2-(2-ethylhexyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (an alkoxysilane N-position-modified compound represented by formula (6), in which R ２ is a methyl group, R ３ is a propylene group, R ６ is a 2-ethylhexyl group, and n is 0) / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(2-ethylhexyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (in the compound represented by formula (8), R ２ is a methyl group, R ３ is a propylene group, R ６This yielded 186 parts of a mixture containing two primary amino groups (a compound in which n is a 2-ethylhexyl group and n is 0) in a molar ratio of 66 / 17 / 17. The total amount of (primary amino groups + secondary amino groups) per gram of the mixture was 2.24 mmol. Into a separate flask were placed 296 parts of mineral spirits, 242 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 500 parts of "Duranate TSA-100," and the mixture was stirred at room temperature. To this was added dropwise 164 parts of a mixture containing 3-(N-(2-(2-ethylhexyloxycarbonyl)ethyl)amino)propyltrimethoxysilane / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(2-ethylhexyloxycarbonyl)ethyl)amino)propyltrimethoxysilane in a molar ratio of 66 / 17 / 17 over 2 hours, and the mixture was then maintained at 60°C for 2 hours and cooled to room temperature to obtain a polyisocyanate curing agent solution (HE-10) with a non-volatile content of 55%. The concentration of isocyanate groups contained in the curing agent solution (HE-10) was 1.73 mmol / g (3.15 mmol / g in terms of non-volatile content).

[0152] Example 11 89.5 parts of 3-aminopropyltrimethoxysilane, 0.04 parts of methoquinone, and 4 parts of "Swasol 1000" (naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.) were placed in a flask, and air was introduced into the liquid to bubble and stir it. 104 parts of isobornyl acrylate was added dropwise to the liquid over 2 hours, and the mixture was then kept at 50°C for 1 hour. Further, the mixture was aged at 50°C for 1 week to obtain 3-(N-(2-(isobornyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (alkoxysilane N-position-modified represented by formula (6) where R ２ is a methyl group, R ３ is a propylene group, R ６ is an isobornyl group, and n is 0) / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(isobornyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (in the compound represented by formula (8), R ２ is a methyl group, R ３ is a propylene group, R ６This yielded 198 parts of a mixture containing two primary amino groups (a compound in which n is an isobornyl group and n is 0) in a molar ratio of 74 / 13 / 13. The total amount of (primary amino groups + secondary amino groups) per gram of the mixture was 2.20 mmol. Into a separate flask were placed 297 parts of mineral spirits, 243 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 500 parts of "Duranate TSA-100," and the mixture was stirred at room temperature. To this was added dropwise 167 parts of a mixture containing 3-(N-(2-(isobornyloxycarbonyl)ethyl)amino)propyltrimethoxysilane / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(isobornyloxycarbonyl)ethyl)amino)propyltrimethoxysilane in a molar ratio of 74 / 13 / 13 over 2 hours, and the mixture was then maintained at 60°C for 2 hours and cooled to room temperature to obtain a polyisocyanate curing agent solution (HE-11) with a non-volatile content of 55%. The concentration of isocyanate groups contained in the curing agent solution (HE-11) was 1.73 mmol / g (3.14 mmol / g in terms of non-volatile content).

[0153] Example 12 221 parts of 3-aminopropyltriethoxysilane, 0.07 parts of methoquinone, and 7 parts of "Swasol 1000" (a naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.) were placed in a flask, and air was introduced into the liquid to bubble and stir it. 128 parts of i-butyl acrylate was added dropwise to the liquid over 2 hours, and the mixture was then kept at 50°C for 1 hour. Further, the mixture was aged at 50°C for 1 week to obtain 3-(N-(2-(i-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (an alkoxysilane N-position-modified compound represented by formula (6), in which R ２ is a methyl group, R ３ is a propylene group, R ６ is an i-butyl group, and n is 0) / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(i-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (in the compound represented by formula (8), R ２ is a methyl group, R ３ is a propylene group, R ６This yielded 356 parts of a mixture containing two primary amino groups (a compound in which n is an i-butyl group and n is 0) in a molar ratio of 80 / 10 / 10. The total amount of (primary amino groups + secondary amino groups) per gram of the mixture was 2.53 mmol. Into a separate flask were placed 298 parts of mineral spirits, 235 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 500 parts of "Duranate TSA-100," and the mixture was stirred at room temperature. To this was added dropwise 145 parts of a mixture containing 3-(N-(2-(i-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(i-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane in a molar ratio of 80 / 10 / 10 over 2 hours, and the mixture was then maintained at 60°C for 2 hours and cooled to room temperature to obtain a polyisocyanate curing agent solution (HE-12) with a non-volatile content of 55%. The concentration of isocyanate groups contained in the curing agent solution (HE-12) was 1.78 mmol / g (3.24 mmol / g in terms of non-volatile content).

[0154] Example 13 179 parts of 3-aminopropyltrimethoxysilane, 0.07 parts of methoquinone, and 6 parts of "Swasol 1000" (a naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.) were placed in a flask, and air was introduced into the liquid to bubble and stir it. 128 parts of t-butyl acrylate was added dropwise to the liquid over 2 hours, and the mixture was then kept at 50°C for 1 hour. Further, the mixture was aged at 50°C for 1 week to obtain 3-(N-(2-(t-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (an alkoxysilane N-position-modified compound represented by formula (6) in which R ２ is a methyl group, R ３ is a propylene group, R ６ is a t-butyl group, and n is 0) / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(t-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (in the compound represented by formula (8), R ２ is a methyl group, R ３ is a propylene group, R ６This yielded 313 parts of a mixture containing two primary amino groups (a compound in which n is a t-butyl group and n is 0) in a molar ratio of 78 / 11 / 11. The total amount of (primary amino groups + secondary amino groups) per gram of the mixture was 2.84 mmol. Into a separate flask were placed 348 parts of mineral spirits, 284 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 500 parts of "Duranate TSA-100," and the mixture was stirred at room temperature. To this was added dropwise 285 parts of a mixture containing 3-(N-(2-(t-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(t-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane in a molar ratio of 78 / 11 / 11 over 2 hours, and the mixture was then maintained at 60°C for 2 hours and cooled to room temperature to obtain a polyisocyanate curing agent solution (HE-13) with a non-volatile content of 55%. The concentration of isocyanate groups contained in the curing agent solution (HE-13) was 1.16 mmol / g (2.11 mmol / g in terms of non-volatile content).

[0155] Example 14 89.5 parts of 3-aminopropyltrimethoxysilane, 0.04 parts of methoquinone, and 4 parts of "Swasol 1000" (naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.) were placed in a flask, and air was introduced into the liquid to bubble and stir it. 104 parts of isobornyl acrylate was added dropwise to the liquid over 2 hours, and the mixture was then kept at 50°C for 1 hour. Further, the mixture was aged at 50°C for 1 week to obtain 3-(N-(2-(isobornyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (alkoxysilane N-position-modified represented by formula (6) where R ２ is a methyl group, R ３ is a propylene group, R ６ is an isobornyl group, and n is 0) / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(isobornyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (in the compound represented by formula (8), R ２ is a methyl group, R ３ is a propylene group, R ６This yielded 198 parts of a mixture containing two primary amino groups (a compound in which n is an isobornyl group and n is 0) in a molar ratio of 74 / 13 / 13. The total amount of (primary amino groups + secondary amino groups) per gram of the mixture was 2.20 mmol. Into a separate flask were placed 273 parts of mineral spirits, 223 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 500 parts of "Duranate TSA-100," and the mixture was stirred at room temperature. To this was added dropwise 111 parts of a mixture containing 3-(N-(2-(isobornyloxycarbonyl)ethyl)amino)propyltrimethoxysilane / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(isobornyloxycarbonyl)ethyl)amino)propyltrimethoxysilane in a molar ratio of 74 / 13 / 13 over 2 hours, and the mixture was then maintained at 60°C for 2 hours and cooled to room temperature to obtain a polyisocyanate curing agent solution (HE-14) with a non-volatile content of 55%. The concentration of isocyanate groups contained in the curing agent solution (HE14) was 1.99 mmol / g (3.62 mmol / g in terms of non-volatile content).

[0156] Example 15 179 parts of 3-aminopropyltrimethoxysilane, 0.07 parts of methoquinone, and 6 parts of "Swasol 1000" (a naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.) were placed in a flask, and air was introduced into the liquid to bubble and stir it. 141 parts of i-butyl acrylate was added dropwise to the liquid over 2 hours, and the mixture was then kept at 50°C for 1 hour. Further, the mixture was aged at 50°C for 1 week to obtain 3-(N-(2-(i-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (an alkoxysilane N-position-modified compound represented by formula (6) in which R ２ is a methyl group, R ３ is a propylene group, R ６ is an i-butyl group, and n is 0) / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(i-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (in the compound represented by formula (8), R ２ is a methyl group, R ３ is a propylene group, R ６This yielded 326 parts of a mixture containing two primary amino groups (a compound in which n is an i-butyl group and n is 0) in a molar ratio of 77 / 6 / 17. The total amount of (primary amino groups + secondary amino groups) per gram of the mixture was 2.55 mmol. Into a separate flask were placed 308 parts of mineral spirits, 252 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 500 parts of "Duranate TSA-100," and the mixture was stirred at room temperature. To this was added dropwise 192 parts of a mixture containing 3-(N-(2-(i-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(i-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane in a molar ratio of 77 / 6 / 17 over 2 hours, and the mixture was then maintained at 60°C for 2 hours and cooled to room temperature to obtain a polyisocyanate curing agent solution (HE-15) with a non-volatile content of 55%. The concentration of isocyanate groups contained in the curing agent solution (HE-15) was 1.57 mmol / g (2.85 mmol / g in terms of non-volatile content).

[0157] Example 16 110.5 parts of 3-aminopropyltriethoxysilane, 0.04 parts of methoquinone, and 4 parts of "Swasol 1000" (naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.) were placed in a flask, and air was introduced into the liquid to bubble and stir it. 93.6 parts of isobornyl acrylate was added dropwise to the liquid over 2 hours, and the mixture was then kept at 50°C for 1 hour. Further, the mixture was aged at 50°C for 1 week to obtain 3-(N-(2-(isobornyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (alkoxysilane N-position-modified represented by formula (6) where R ２ is a methyl group, R ３ is a propylene group, R ６ is an isobornyl group, and n is 0) / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(isobornyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (in the alkoxysilane N-position modified compound represented by formula (8), R ２ is a methyl group, R ３ is a propylene group, R ６This yielded 208 parts of a mixture containing two primary amino groups (a compound in which n is an isobornyl group and n is 0) in a molar ratio of 80 / 15 / 5. The total amount of (primary amino groups + secondary amino groups) per gram of the mixture was 2.28 mmol. Into a separate flask were placed 271 parts of mineral spirits, 222 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 500 parts of "Duranate TSA-100," and the mixture was stirred at room temperature. To this was added dropwise 108 parts of a mixture containing 3-(N-(2-(isobornyloxycarbonyl)ethyl)amino)propyltrimethoxysilane / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(isobornyloxycarbonyl)ethyl)amino)propyltrimethoxysilane in a molar ratio of 80 / 15 / 15 over 2 hours, and the mixture was then maintained at 60°C for 2 hours and cooled to room temperature to obtain a polyisocyanate curing agent solution (HE-16) with a non-volatile content of 55%. The concentration of isocyanate groups contained in the curing agent solution (HE-16) was 2.01 mmol / g (3.65 mmol / g in terms of non-volatile content).

[0158] Comparative Example 5 179 parts of 3-aminopropyltrimethoxysilane, 0.07 parts of methoquinone, and 6 parts of "Swasol 1000" (naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.) were placed in a flask, and air was introduced into the liquid to bubble and stir it. 128 parts of n-butyl acrylate was added dropwise to the liquid over 2 hours, and the mixture was then kept at 50°C for 1 hour. Further, the mixture was aged at 50°C for 1 week to obtain 3-(N-(2-(n-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (alkoxysilane N-position-modified compound represented by formula (6) in which R ２ is a methyl group, R ３ is a propylene group, R ６ is an n-butyl group, and n is 0) / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(n-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (in the compound represented by formula (8), R ２ is a methyl group, R ３ is a propylene group, R ６This yielded 313 parts of a mixture containing two primary amino groups (a compound in which n is an n-butyl group and n is 0) in a molar ratio of 66 / 17 / 17. The total amount of (primary amino groups + secondary amino groups) per gram of the mixture was 2.65 mmol. Into a separate flask were placed 285 parts of mineral spirits, 233 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 500 parts of "Duranate TSA-100," and the mixture was stirred at room temperature. To this was added dropwise 139 parts of a mixture containing 3-(N-(2-(n-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(n-butyloxycarbonyl)ethyl)amino)propyltrimethoxysilane in a molar ratio of 66 / 17 / 17 over 2 hours, and the mixture was then maintained at 60°C for 2 hours and cooled to room temperature to obtain a polyisocyanate curing agent solution (HR-5) with a non-volatile content of 55%. The concentration of isocyanate groups contained in the curing agent solution (HR-5) was 1.80 mmol / g (3.28 mmol / g in terms of non-volatile content).

[0159] Comparative Example 6 179 parts of 3-aminopropyltrimethoxysilane, 0.07 parts of methoquinone, and 6 parts of "Swasol 1000" (a naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.) were placed in a flask, and air was introduced into the liquid to bubble and stir it. 100 parts of ethyl acrylate was added dropwise to the liquid over 2 hours, and the mixture was then kept at 50°C for 1 hour. Further, the mixture was aged at 50°C for 1 week to obtain 3-(N-(2-(ethyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (an alkoxysilane N-position-modified compound represented by formula (6) in which R ２ is a methyl group, R ３ is a propylene group, R ６ is an ethyl group and n is 0) / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(ethyloxycarbonyl)ethyl)amino)propyltrimethoxysilane (a compound represented by formula (8), in which R ２ is a methyl group, R ３ is a propylene group, R ６This yielded 285 parts of a mixture containing two primary amino groups (a compound in which n is an ethyl group and n is 0) in a molar ratio of 66 / 17 / 17. The total amount of (primary amino groups + secondary amino groups) per gram of the mixture was 2.91 mmol. Into a separate flask were placed 297 parts of mineral spirits, 243 parts of "Swasol 1000" (a naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 500 parts of "Duranate TSA-100," and the mixture was stirred at room temperature. To this was added dropwise 169 parts of a mixture containing 3-(N-(2-(ethyloxycarbonyl)ethyl)amino)propyltrimethoxysilane / 3-aminopropyltrimethoxysilane / 3-(N,N-di(2-(ethyloxycarbonyl)ethyl)amino)propyltrimethoxysilane in a molar ratio of 66 / 17 / 17 over 2 hours, and the mixture was then maintained at 60°C for 2 hours and cooled to room temperature to obtain a polyisocyanate curing agent solution (HR-6) with a non-volatile content of 55%. The concentration of isocyanate groups contained in the curing agent solution (HR-6) was 1.62 mmol / g (2.95 mmol / g in terms of non-volatile content).

[0160] Comparative Example 7 225 parts of mineral spirits, 184 parts of "Swasol 1000" (naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.), and 500 parts of "Duranate TSA-100" were placed in a container and stirred at room temperature to obtain a polyisocyanate curing agent solution (HR-7) (non-volatile content concentration: 55%) that had not been modified with aminoalkoxysilane or unsaturated carboxylic acid dialkyl ester. The concentration of isocyanate groups contained in 1 g of curing agent solution (HR-7) was 2.70 mmol / g (4.91 mmol / g in terms of non-volatile content).

[0161] Comparative Example 8 179 parts of 3-aminopropyltrimethoxysilane, 0.07 parts of methoquinone, and 4 parts of "Swasol 1000" (naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.) were placed in a flask, the temperature was raised to 80°C, and air was introduced into the liquid to bubble and stir, yielding 183 parts of a mixture. In a separate flask, 254 parts of mineral spirits, 208 parts of "Swasol 1000" (naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.), and 500 parts of "Duranate TSA-100" were placed, and the mixture was stirred at room temperature. To this was added dropwise 67 parts of the mixture containing 3-aminopropyltrimethoxysilane over 2 hours, and then the mixture was maintained at 60°C for 1 hour and cooled to room temperature in an attempt to obtain a polyisocyanate curing agent solution (HR-8) (non-volatile concentration: 54%) that had been modified with aminoalkoxysilane but not modified with unsaturated carboxylic acid dialkyl ester. However, the curing agent precipitated and became non-uniform, making the solution unusable as a curing agent solution, and further evaluation was discontinued.

[0162]

[0163] (Note 3) The molar ratio of 3-(N-(2-(alkoxycarbonyl)ethyl)amino)propyltrialkoxysilane / 3-aminopropyltrialkoxysilane / 3-(N,N-di(2-(alkoxycarbonyl)ethyl)amino)propyltrialkoxysilane in the mixture was calculated by converting from the proton integral value of H NMR (proton nuclear magnetic resonance analysis). [Evaluation items] (*) Condition of the curing agent solution After production, each curing agent solution was sealed in a 250 ml glass bottle and stored in a sealed state in a temperature-controlled room at 20°C and 60% humidity for three months, and after storage in a sealed state in a temperature-controlled room at 5°C and 60% humidity for two weeks. In the table, a rank of ◯ was judged to be pass, and ranks × and XX were judged to be fail. ◯: No two-layer separation, turbidity, or precipitate was observed in the hardener solution, and no abnormalities were observed. ×: Either two-layer separation or turbidity was observed in the hardener solution. XX: A starch syrup-like polymer precipitated from the hardener solution.

[0164] [Production of Modified Polyisocyanate Using Saturated Carboxylic Acid Alkyl Ester] Example 17 A flask under a nitrogen atmosphere was charged with 89 parts of methyl acetate, a linear saturated ester, and 179 parts of 3-aminopropyltrimethoxysilane, and the mixture was stirred at room temperature. 0.58 parts of a 28% methanol solution of sodium methoxide was added as a catalyst, and the mixture was stirred. The temperature was raised to 70°C and aged for one day. The reaction rate of 3-aminopropyltrimethoxysilane was 97%, and methanol was by-produced in an amount approximately equimolar to the reacted 3-aminopropyltrimethoxysilane. Subsequently, 1.1 parts of bis(2-ethylhexyl)phosphoric acid was added as an acidic compound, and the mixture was concentrated under reduced pressure at 50°C to 70°C to remove methanol and remaining methyl acetate. As a result, crude 3-acetamidopropyltrimethoxysilane (R ２ is a methyl group, R ３ is a propylene group, R ７ A compound in which n is a methyl group and n is 0 was obtained (222 parts). Into a separate flask under a nitrogen atmosphere, 250 parts of mineral spirits, 204 parts of "Swasol 1000" (naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 500 parts of "Duranate TSA-100" were placed and stirred at room temperature. 55 parts of crude 3-acetamidopropyltrimethoxysilane was added to this, and the mixture was heated at 110°C for 10 hours to adduct the secondary amide groups to isocyanate groups, yielding a polyisocyanate curing agent solution (HE-17) with a non-volatile content of 55%. The concentration of isocyanate groups contained in the curing agent solution (HE-17) was 2.14 mmol / g (3.89 mmol / g in terms of non-volatile content).

[0165] Example 18: 89 parts of methyl acetate, a linear saturated ester, and 179 parts of 3-aminopropyltrimethoxysilane were placed in a flask under a nitrogen atmosphere and stirred at room temperature. 0.58 parts of a 28% methanol solution of sodium methoxide was added as a catalyst, and the mixture was stirred. The temperature was raised to 70°C and aged for one day. The conversion of 3-aminopropyltrimethoxysilane was 97%, and methanol was by-produced in an amount approximately equimolar to the reacted 3-aminopropyltrimethoxysilane. Thereafter, 0.58 parts of p-toluenesulfonic acid was added as an acidic compound, and the mixture was concentrated under reduced pressure at 50°C to 70°C to remove methanol and remaining methyl acetate. As a result, crude 3-acetamidopropyltrimethoxysilane (represented by the formula (7), where R ２ is a methyl group, R ３ is a propylene group, R ７ A compound in which n is a methyl group and n is 0 was obtained (222 parts). 62 parts of butyl acetate and 500 parts of "Duranate TSA-100" were placed in a separate flask under a nitrogen atmosphere and stirred at room temperature. 55 parts of crude 3-acetamidopropyltrimethoxysilane was added thereto and heated at 110°C for 7 hours to adduct the secondary amide groups to isocyanate groups, yielding a polyisocyanate curing agent solution (HE-18) with a non-volatile content of 90%. The concentration of isocyanate groups contained in the curing agent solution (HE-18) was 3.49 mmol / g (3.88 mmol / g in terms of non-volatile content).

[0166] Example 19: 89 parts of methyl acetate, a linear saturated ester, and 179 parts of 3-aminopropyltrimethoxysilane were placed in a flask under a nitrogen atmosphere and stirred at room temperature. 0.58 parts of a 28% methanol solution of sodium methoxide was added as a catalyst, and the mixture was stirred. The temperature was raised to 70°C and aged for one day. The conversion of 3-aminopropyltrimethoxysilane was 97%, and methanol was by-produced in an amount approximately equimolar to the reacted 3-aminopropyltrimethoxysilane. Subsequently, 1.1 parts of bis(2-ethylhexyl)phosphoric acid was added as an acidic compound, and the mixture was concentrated under reduced pressure at 50°C to 70°C to remove methanol and remaining methyl acetate. As a result, crude 3-acetamidopropyltrimethoxysilane (represented by the formula (7), where R ２ is a methyl group, R ３ is a propylene group, R ７ A compound in which n is a methyl group and n is 0 was obtained (222 parts). 62 parts of butyl acetate and 500 parts of "Duranate TSA-100" were placed in a separate flask under a nitrogen atmosphere and stirred at room temperature. 55 parts of crude 3-acetamidopropyltrimethoxysilane was added thereto and heated at 110°C for 7 hours to adduct the secondary amide groups to isocyanate groups, yielding a polyisocyanate curing agent solution (HE-19) with a non-volatile content of 90%. The concentration of isocyanate groups contained in the curing agent solution (HE-19) was 3.49 mmol / g (3.88 mmol / g in terms of non-volatile content).

[0167] Example 20: 89 parts of methyl acetate, a linear saturated ester, and 179 parts of 3-aminopropyltrimethoxysilane were placed in a flask under a nitrogen atmosphere and stirred at room temperature. 0.58 parts of a 28% methanol solution of sodium methoxide was added as a catalyst, and the mixture was stirred. The temperature was raised to 70°C and aged for one day. The reaction rate of 3-aminopropyltrimethoxysilane was 97%, and methanol was by-produced in an amount approximately equimolar to the reacted 3-aminopropyltrimethoxysilane. Subsequently, 1.03 parts of dodecylbenzenesulfonic acid was added as an acidic compound, and the mixture was concentrated under reduced pressure at 50°C to 70°C to remove methanol and remaining methyl acetate. As a result, crude 3-acetamidopropyltrimethoxysilane (R ２ is a methyl group, R ３ is a propylene group, R ７ A compound in which n is a methyl group and n is 0 was obtained (222 parts). 62 parts of butyl acetate and 500 parts of "Duranate TSA-100" were placed in a separate flask under a nitrogen atmosphere and stirred at room temperature. 55 parts of crude 3-acetamidopropyltrimethoxysilane was added thereto and heated at 110°C for 7 hours to adduct the secondary amide groups to isocyanate groups, yielding a polyisocyanate curing agent solution (HE-20) with a non-volatile content of 90%. The concentration of isocyanate groups contained in the curing agent solution (HE-20) was 3.49 mmol / g (3.88 mmol / g in terms of non-volatile content).

[0168] Example 21: 190 parts of methyl octanoate, a linear saturated ester, and 179 parts of 3-aminopropyltrimethoxysilane were placed in a flask under a nitrogen atmosphere and stirred at room temperature. 1.16 parts of a 28% methanol solution of sodium methoxide was added as a catalyst, and the mixture was stirred. The temperature was raised to 70°C and aged for 2 days. The conversion of 3-aminopropyltrimethoxysilane was 94%, and methanol was by-produced in an amount approximately equimolar to the reacted 3-aminopropyltrimethoxysilane. 2.2 parts of bis(2-ethylhexyl)phosphoric acid was then added as an acidic compound, and the mixture was concentrated at 50°C to 70°C under reduced pressure to remove methanol. As a result, crude 3-octanamidopropyltrimethoxysilane (R ２ is a methyl group, R ３ is a propylene group, R ７ is a heptyl group, and n is 0), 331 parts of a compound. 65 parts of butyl acetate and 500 parts of "Duranate TSA-100" were placed in a separate flask under a nitrogen atmosphere and stirred at room temperature. 82 parts of crude 3-octanamidopropyltrimethoxysilane was added to this, and the mixture was heated at 110°C for 12 hours to adduct the secondary amide groups with isocyanate groups. After cooling, the mixture was filtered through filter paper to obtain a polyisocyanate curing agent solution (HE-21) with a non-volatile content of 90%. The concentration of isocyanate groups contained in the curing agent solution (HE-21) was 3.18 mmol / g (3.53 mmol / g in terms of non-volatile content).

[0169] Example 22: 106 parts of methyl propionate, a linear saturated ester, and 179 parts of 3-aminopropyltrimethoxysilane were placed in a flask under a nitrogen atmosphere and stirred at room temperature. 0.58 parts of a 28% methanol solution of sodium methoxide was added as a catalyst, and the mixture was stirred. The temperature was raised to 70°C and aged for 2 days. The reaction rate of 3-aminopropyltrimethoxysilane was 97%, and methanol was by-produced in an amount approximately equimolar to the reacted 3-aminopropyltrimethoxysilane. Subsequently, 1.1 parts of bis(2-ethylhexyl)phosphoric acid was added as an acidic compound, and the mixture was concentrated under reduced pressure at 50°C to 80°C to remove methanol and remaining methyl propionate. As a result, crude 3-propanamidopropyltrimethoxysilane (R ２ is a methyl group, R ３ is a propylene group, R ７ is an ethyl group, and n is 0), 236 parts of a compound. 60 parts of butyl acetate and 500 parts of "Duranate TSA-100" were placed in a separate flask under a nitrogen atmosphere and stirred at room temperature. 41 parts of crude 3-propanamidopropyltrimethoxysilane was added thereto and heated at 110°C for 9 hours to adduct the secondary amide groups to isocyanate groups, yielding a polyisocyanate curing agent solution (HE-22) with a non-volatile content of 90%. The concentration of isocyanate groups contained in the curing agent solution (HE-22) was 3.67 mmol / g (4.08 mmol / g in terms of non-volatile content).

[0170] Example 23: 96 parts of methyl acetate, a linear saturated ester, and 179 parts of 3-aminopropyltrimethoxysilane were placed in a flask under a nitrogen atmosphere and stirred at room temperature. 0.58 parts of a 28% methanol solution of sodium methoxide was added as a catalyst, and the mixture was stirred. The temperature was raised to 70°C and aged for one day. The reaction rate of 3-aminopropyltrimethoxysilane was 98%, and methanol was by-produced in an amount approximately equimolar to the reacted 3-aminopropyltrimethoxysilane. 1.1 parts of bis(2-ethylhexyl)phosphoric acid was then added as an acidic compound, and the mixture was concentrated by removing methanol and remaining methyl acetate under reduced pressure at 50°C to 70°C. Further, vacuum distillation was carried out at a vacuum of 4 mmHg to obtain purified 3-acetamidopropyltrimethoxysilane (R ２ is a methyl group, R ３ is a propylene group, R ７ is a methyl group, and n is 0) to obtain 200 parts. Into a separate flask under a nitrogen atmosphere, 114 parts of propylene glycol monomethyl ether acetate and 500 parts of "Sumidur N-3300" (hexamethylene diisocyanate-based isocyanurate polyisocyanate, product name, isocyanate group content 21.8 wt%) were placed and stirred at room temperature. 144 parts of purified 3-acetamidopropyltrimethoxysilane was added to this and heated at 110°C for 9 hours to adduct the secondary amide groups to isocyanate groups, obtaining a polyisocyanate curing agent solution (HE-23) with a non-volatile content of 85%. The concentration of isocyanate groups contained in the curing agent solution (HE-23) was 2.50 mmol / g (2.94 mmol / g in terms of non-volatile content).

[0171] Example 24 206 parts of methyl 3,3,5-trimethylhexanoate, a branched saturated ester having two hydrogen atoms at the α-position, and 179 parts of 3-aminopropyltrimethoxysilane were placed in a flask under a nitrogen atmosphere and stirred at room temperature. 1.16 parts of a 28% methanol solution of sodium methoxide was added as a catalyst, and the mixture was stirred. The temperature was raised to 70°C and aged for 2 days. The reaction rate of 3-aminopropyltrimethoxysilane was 71%, and methanol was by-produced in an amount approximately equimolar to the reacted 3-aminopropyltrimethoxysilane. 2.2 parts of bis(2-ethylhexyl)phosphoric acid was then added as an acidic compound, and the mixture was concentrated by removing methanol under reduced pressure at 50°C to 70°C. Further, the mixture was distilled under reduced pressure at a vacuum of 4 mmHg to obtain purified 3-(3,3,5-trimethylhexanamido)propyltrimethoxysilane (in formula (7), R ２ is a methyl group, R ３ is a propylene group, R ７ A compound in which n is 2,2,4-trimethylpentyl groups and n is 0 was obtained (170 parts). 64 parts of butyl acetate and 500 parts of "Duranate TSA-100" were placed in a separate flask under a nitrogen atmosphere and stirred at room temperature. 79 parts of purified 3-(3,3,5-trimethylhexanamido)propyltrimethoxysilane was added thereto and heated at 110°C for 9 hours to adduct the secondary amide groups to isocyanate groups, yielding a polyisocyanate curing agent solution (HE-24) with a nonvolatile content of 90%. The concentration of isocyanate groups contained in the curing agent solution (HE-24) was 3.39 mmol / g (3.77 mmol / g in terms of nonvolatile content).

[0172] Example 25 Crude 3-acetamidopropyltrimethoxysilane (R ２ is a methyl group, R ３ is a propylene group, R ７is a methyl group, and n is 0) to obtain 222 parts. Into a separate flask under a nitrogen atmosphere, 62 parts of propylene glycol monomethyl ether acetate and 500 parts of "Duranate TSA-100" were placed and stirred at room temperature. 55 parts of crude 3-acetamidopropyltrimethoxysilane was added, and the mixture was heated at 110°C for 7 hours to adduct the secondary amide groups to isocyanate groups, obtaining a polyisocyanate curing agent solution (HE-25) with a non-volatile content of 90%. The concentration of isocyanate groups contained in the curing agent solution (HE-25) was 3.13 mmol / g (3.48 mmol / g in terms of non-volatile content).

[0173] Example 26: 206 parts of methyl 3,3,5-trimethylhexanoate, a branched saturated ester having two hydrogen atoms at the α-position, and 179 parts of 3-aminopropyltrimethoxysilane were placed in a flask under a nitrogen atmosphere and stirred at room temperature. 1.16 parts of a 28% methanol solution of sodium methoxide was added as a catalyst, and the mixture was stirred. The temperature was raised to 70°C and aged for 2 days. The conversion of 3-aminopropyltrimethoxysilane was 71%, and methanol was by-produced in an amount approximately equimolar to the reacted 3-aminopropyltrimethoxysilane. 2.2 parts of bis(2-ethylhexyl)phosphoric acid was then added as an acidic compound, and the mixture was concentrated at 50°C to 70°C under reduced pressure to remove methanol. This afforded crude 3-(3,3,5-trimethylhexanamido)propyltrimethoxysilane (in formula (7), R ２ is a methyl group, R ３ is a propylene group, R ７365 parts of a compound in which n is 2,2,4-trimethylpentyl and n is 0 were obtained. Because this was not purified by distillation, a large amount of 3-aminopropyltrimethoxysilane derived from the raw materials remained, and the resulting solution was a mixture of 71 mol % 3-(3,3,5-trimethylhexanamido)propyltrimethoxysilane and 29 mol % 3-aminopropyltrimethoxysilane. In a separate flask under a nitrogen atmosphere, 65 parts of propylene glycol monomethyl ether acetate and 500 parts of "Duranate TSA-100" were placed and stirred at room temperature. 90 parts of crude 3-(3,3,5-trimethylhexanamido)propyltrimethoxysilane was added, and the mixture was heated at 110°C for 7 hours to adduct the secondary amide groups to isocyanate groups, yielding a polyisocyanate curing agent solution (HE-26) with a non-volatile concentration of 90%. The concentration of isocyanate groups contained in the curing agent solution (HE-26) was 3.25 mmol / g (3.61 mmol / g in terms of nonvolatile content).

[0174] Comparative Example 9: 56 parts of butyl acetate and 500 parts of "Duranate TSA-100" were placed in a flask under a nitrogen atmosphere and stirred at room temperature to obtain a polyisocyanate curing agent solution (HR-9) with a nonvolatile content of 90%. The concentration of isocyanate groups in the curing agent solution (HR-9) was 4.46 mmol / g (4.96 mmol / g in terms of nonvolatile content).

[0175] Comparative Example 10: 248 parts of mineral spirits, 198 parts of "Swasol 1000" (naphtha-based solvent, product name, manufactured by Maruzen Petrochemical Co., Ltd.), and 500 parts of "Duranate TSA-100" were placed in a flask under a nitrogen atmosphere and stirred at room temperature. When 44.3 parts of 3-aminopropyltrimethoxysilane was added dropwise to the mixture, a curing agent solution (HR-10) was obtained, but a starch syrup-like substance began to precipitate, so the study was discontinued.

[0176]

[0177] [Evaluation items] (*) Formation of N-acyl modified products The formation rate (%) of N-acyl modified products in Examples 17 to 26 was calculated and evaluated according to the following criteria. GOOD, FAIR, and POOR in the table have the following meanings. The higher the formation rate (%), the better the result. Good: 80% or more, Fair: 30% or more but less than 80%, Poor: less than 30%.

[0178] (*) Ease of production of intermediates containing N-acyl modified compounds The ease of production of the polyisocyanate curing agent solutions obtained in Examples 17 to 26 was evaluated according to the following criteria. AA and A were judged to be acceptable. Note that "Y" in the "Distillation Apparatus Application" column indicates that a distillation apparatus is applied, and "N" indicates that a distillation apparatus is not applied. AA: Production possible without a distillation apparatus, A: Production possible with a distillation apparatus, B: Production difficult even with a distillation apparatus due to low production rate of N-acyl modified compounds. (*) Isocyanate group stability at 20°C The residual NCO ratio in the polyisocyanate curing agent solutions obtained in Examples 17 to 26 and Comparative Example 9 after 3 months at 20°C was measured using the same procedure as in Example 1 and evaluated according to the following criteria. The higher the residual ratio (%), the better the result.

[0179] Good: 95% or more, Fair: 90% or more but less than 95%, Poor: less than 90%.

[0180] [Preparation of Clear Coatings] Examples 27 to 57 and Comparative Examples 11 to 18 Base resins were prepared according to the formulations shown in Tables 4, 5, and 6 below, and polyisocyanate curing agent solutions (HE-1) to (HE-26), (HR-1) to (HR-3), (HR-5) to (HR-7), and (HR-9) that had been prepared three days earlier were mixed to obtain clear coatings (U-1) to (U-41). Similarly, the base resins shown in Table 4 were mixed with polyisocyanate curing agent solutions (HE-1) to (HE-7), and (HR-3) that had been prepared 12 months earlier to produce clear coatings (U'-1) to (U'-9), and (U'-12). Additionally, the polyisocyanate curing agent solutions (HE-8) to (HE-16), (HR-5) to (HR-7) that had been produced three months earlier were mixed with the base resins listed in Table 5 to produce clear coatings (U'-13) to (U'-26). Similarly, the polyisocyanate curing agent solutions (HE-8) to (HE-16), and (HR-7) that had been produced and stored in a sealed container at 5°C for two weeks were mixed with the base resins listed in Table 5 to produce clear coatings (U"-13) to (U"-23), and (U"-26). Similarly, the polyisocyanate curing agent solutions (HE-17) to (HE-26), and (HR-9) that had been produced three months earlier were mixed with the base resins listed in Table 6 to produce clear coatings (U'-27) to (U'-41).

[0181] The values ​​in Tables 4, 5 and 6 do not represent the mass of the nonvolatile components, but the total mass including the volatile components.

[0182]

[0183]

[0184]

[0185] (Note 4) Polyol solution 1: styrene / i-butyl methacrylate / 2-ethylhexyl acrylate / hydroxyethyl methacrylate = 30 / 30 / 30 / 10 copolymer solution, weight average molecular weight 20,000, hydroxyl value per non-volatile content 43 mg KOH / g, non-volatile content 50%, solvent: mineral spirits / "Swasol 1000" mass ratio = 1 / 1 (Note 5) Polyol solution 2: styrene / i-butyl methacrylate / 2-ethylhexyl acrylate / hydroxyethyl methacrylate / acrylic acid = 30 / 35 / 29 / 5 / 1 copolymer solution, weight average molecular weight 20,000, hydroxyl value per non-volatile content 22 mg KOH / g, non-volatile content 50%, solvent: mineral spirits / "Swasol 1000" mass ratio = 1 / 1 (Note 6) Aspartic acid ester 1: Desmophen NH1523LF (N,N'-(methylenebis(2-methyl-di-4,1-cyclohexanediyl))-bisaspartic acid tetraethyl ester, content > 99%, amine value 200 mg KOH / g) manufactured by Covestro. (Note 7) Neostan U-830: Trade name, manufactured by Nitto Kasei Co., Ltd., dioctyl tin compound. (Note 8) Aspartic acid ester 2: Desmophen NH1423LF (N,N'-(methylenebis(di-4,1-cyclohexanediyl))-bisaspartic acid tetraethyl ester, content > 99%, amine value 205 mg KOH / g) manufactured by Covestro.

[0186] [Performance Evaluation] The following performance evaluation tests were conducted on each of the clear coatings obtained in the above Examples and Comparative Examples. In this test, the coating was performed immediately after mixing the base resin and curing agent. (*) Curability: Each clear coating was applied to a glass plate using a 200 μm applicator and dried for 7 days in a chamber at room temperature of 23°C and 50% humidity. The resulting coating film was peeled off from the glass plate, wrapped in a 200-mesh stainless steel wire mesh, and immersed in a mixed solution of acetone / methanol in a mass ratio of 1 / 1 for 24 hours. The wire mesh containing the coating was then removed and dried at 100°C for 1 hour. The insoluble content was measured from the mass of the coating remaining on the wire mesh. Ranks of ◎ and ◯ were deemed acceptable, while ranks of △ and × were deemed unacceptable. ◎: Insoluble content 85% or more; ◯: Insoluble content 70% to less than 85%; △: Insoluble content 55% to less than 70%; ×: Insoluble content less than 55%. (*) Adhesion Two types of metal plates (ferrous metal: degreased SPCC-SD (cold-rolled steel plate with a dull finish) metal plate, and non-ferrous metal: 5052P aluminum plate sanded with 240 grit sandpaper (3.2 mm x 70 mm x 150 mm) were prepared as substrates. Each clear coating was applied to each metal plate using a 200 μm applicator and dried for 7 days in a chamber at a room temperature of 23°C and a humidity of 50% to obtain each test coated plate. A total of 100 squares, 10 squares x 10 squares, were cut into a 2 mm wide grid pattern from above the coating using a cutter, and a peel test was carried out three times in which adhesive tape was applied and then peeled off, and the number of squares that did not peel off was counted. ◎ and ◯ ranks were judged as passing, and △ and × ranks were judged as failing. ◎: 100 squares ◯: 75 to 99 squares △: 51 to 74 squares ×: 50 squares or less (*) Water-resistant adhesion Two types of metal plates, iron and aluminum, were prepared in the same manner as the metal plates used in the above adhesion test. Each clear coating was applied to each metal plate using a 200 μm applicator, and then dried in a chamber at a room temperature of 23° C. and a humidity of 50% for 7 days to obtain each test coated plate.Each test plate was immersed in 40°C warm water for 3 days, then immersed in 20°C water for 1 hour, removed, and the water on the coating surface of the test plate was wiped off. Immediately, a total of 100 squares (10 squares x 10 squares) were cut into a 2mm wide grid using a cutter from above the coating, and a peel test was performed three times in which adhesive tape was attached and then peeled off, and the number of squares that did not peel was counted. ◎ and ◯ ranks were judged as pass, and △ and × ranks were judged as fail. ◎: 100 squares ◯: 75 to 99 squares △: 51 to 74 squares ×: 50 squares or less.

[0187] [Preparation of One-Coat Coatings] Examples 60 to 92 and Comparative Examples 19 to 26 Base resins were prepared according to the formulations shown in Tables 7, 8, and 9 below, and polyisocyanate curing agent solutions (HE-1) to (HE-26), (HR-1) to (HR-3), (HR-5) to (HR-7), and (HR-9) that had been prepared three days earlier were mixed to obtain one-coat coatings (U-42) to (U-82). Similarly, the base resins shown in Table 7 were mixed with older polyisocyanate curing agent solutions (HE-1) to (HE-7), and (HR-3) that had been prepared 12 months earlier to obtain one-coat coatings (U'-42) to (U'-50), and (U'-53). Additionally, polyisocyanate curing agent solutions (HE-8) to (HE-16) and (HR-5) to (HR-7) that had been produced three months earlier were mixed with the base resins listed in Table 8 to produce single-coat coatings (U'-54) to (U'-67), respectively. Similarly, polyisocyanate curing agent solutions (HE-8) to (HE-16) and (HR-7) that had been sealed and stored at 5°C for two weeks after production were mixed with the base resins listed in Table 8 to produce single-coat coatings (U"-54) to (U"-64) and (U"-67), respectively. Similarly, polyisocyanate curing agent solutions (HE-17) to (HE-26) and (HR-9) that had been produced three months earlier were mixed with the base resins listed in Table 9 to produce single-coat coatings (U'-68) to (U'-82), respectively.

[0188] The values ​​in Tables 7, 8 and 9 do not represent the mass of the non-volatile components, but the total mass including the volatile components.

[0189]

[0190]

[0191]

[0192] (Note 9) Anti-rust pigment composition: magnesium phosphate / "Silysia 710" (silica, Fuji Silysia Chemical Co., Ltd., trade name) / calcium silicate = 50 / 30 / 20 mixed and modified.

[0193] [Performance Evaluation] (*) Hardening: This was carried out in the same manner as the hardening test carried out for the clear coating, and was evaluated according to the same criteria. (*) Corrosion resistance: A base agent and a hardening agent were mixed on a zinc phosphate-treated SPCC steel plate (size: 3.2 mm x 70 mm x 150 mm), and one coat of each was applied within 30 minutes at an application rate of 100 g / m. ２ The test panels were brush-painted with a 5% salt spray tester at 35°C for 7 days, and then 8cm long cuts were made with a cutter down to the base material to prepare test panels. The test panels were then tested in a 5% salt spray tester at 35°C for 240 hours, after which the test panels were evaluated on a four-point scale based on their appearance. ◎: The maximum width of rust (on one side) growing from the cut was less than 15mm, and there was no abnormality in the general area. ○: The maximum width of rust (on one side) growing from the cut was 15 to 20mm, and there was no abnormality in the general area. △: The maximum width of rust (on one side) growing from the cut was less than 20mm, but blisters and rust occurred in the general area. ×: The maximum width of rust (on one side) growing from the cut was more than 20mm, and there was blisters and rust in the general area. (*) Weather resistance: A mixture of base agent and curing agent was applied to a zinc phosphate-treated SPCC steel panel, and one coat of each was applied within 30 minutes at a rate of 100g / m. ２ The test panels were brush-painted with a paint and aged at 20°C for 7 days to obtain test panels. These test panels were irradiated for 300 hours in accordance with the accelerated weather resistance test of JIS K 5600, 7-7 (xenon lamp method), and then evaluated according to the following criteria: ⊚: No change in gloss was observed compared to the initial state; ◯: A change in gloss was observed compared to the initial state, but it was not noticeable; △: A clear change in gloss was observed compared to the initial state; ×: A significant change in gloss was observed compared to the initial state.

Claims

1. 1. A modified polyisocyanate for use with an active hydrogen-containing compound as a curing agent for a coating, comprising: It is a reaction product made from raw materials including an alkoxysilane having a primary amino group (a1), a saturated carboxylic acid alkyl ester (a3), and a polyisocyanate (a4) (excluding polyisocyanates based on 1,5-diisocyanatopentane). Modified polyisocyanate.

2. The modified polyisocyanate according to claim 1, wherein the alkoxysilane (a1) having a primary amino group is a compound represented by the following formula (1): 【Chemistry 1】 In formula (1), R １ and R ２ are the same or different and each is an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8 carbon atoms, and n is an integer of 0 to 2.

3. The modified polyisocyanate according to claim 1, wherein the saturated carboxylic acid alkyl ester (a3) ​​is a compound represented by the following formula (4): R ７ -C(=O)-OR ８ (4) In formula (4), R ７ and R ８ are the same or different and represent an alkyl group having 1 to 18 carbon atoms and having no unsaturated group, or a group having 1 to 18 carbon atoms and containing a heteroatom in the alkyl molecule and having no unsaturated group.

4. The modified polyisocyanate according to claim 1, wherein a secondary amide group of an N-position modified alkoxysilane formed by reacting a primary amino group of the alkoxysilane (a1) with an ester group of the saturated carboxylic acid alkyl ester (a3) ​​is adducted to an isocyanate group of the polyisocyanate (a4).

5. The modified polyisocyanate according to claim 4, wherein the reaction ratio of the N-position modified alkoxysilane having a secondary amino group to the polyisocyanate (a4) is such that the amount of secondary amino groups is 40 moles or less per 100 moles of isocyanate groups.

6. The modified polyisocyanate according to claim 4, wherein the N-position modified alkoxysilane obtained by reacting the alkoxysilane (a1) with the saturated carboxylic acid alkyl ester (a3) ​​is an N-position acyl modified product having a secondary amide group and represented by the following formula (7): 【Chemistry 2】 In formula (7), R １ and R ２ are the same or different and each is an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8 carbon atoms, n is an integer of 0 to 2, R ７ represents an alkyl group having 1 to 18 carbon atoms which has no unsaturated group, or a group which contains a heteroatom in the molecule of an alkyl group or arylalkyl group having 1 to 18 carbon atoms which has no unsaturated group.

7. A step (1) of reacting an alkoxysilane (a1) having a primary amino group with a saturated carboxylic acid alkyl ester (a3) ​​in the presence of a basic catalyst; Step (2) of adding an acidic compound; A step (3) of removing a part or all of the alcohol produced as a by-product to prepare an intermediate containing an N-acyl modified product represented by the following formula (7): Step (4) of reacting the intermediate with a polyisocyanate (a4).

2. The modified polyisocyanate of claim 1, produced by 【Chemistry 3】 In formula (7), R １ and R ２ are the same or different and each is an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8 carbon atoms, n is an integer of 0 to 2, R ７ represents an alkyl group having 1 to 18 carbon atoms and having no unsaturated group, or a group having 1 to 18 carbon atoms and containing a heteroatom in the alkyl molecule and having no unsaturated group.

8. The modified polyisocyanate described in claim 7, wherein the step (3) is carried out by removing some or all of the alcohol produced as a by-product by concentration and preparing an intermediate containing an N-acyl modified product represented by the following formula (7) without distillation: 【Chemistry 4】 In formula (7), R 1 and R 2 are the same or different and each is an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8 carbon atoms; n is an integer from 0 to 2; and R 7 is an alkyl group having 1 to 18 carbon atoms that has no unsaturated group, or a group having 1 to 18 carbon atoms that contains a heteroatom in the alkyl molecule and has no unsaturated group.

9. The modified polyisocyanate according to claim 6, wherein the reaction ratio of the N-position acyl modified product to the polyisocyanate (a4) is such that the total number of moles of secondary amide groups and primary amino groups is 40 moles or less per 100 moles of isocyanate groups.

10. A step (1) of reacting an alkoxysilane (a1) having a primary amino group with a saturated carboxylic acid alkyl ester (a3) ​​in the presence of a basic catalyst; Step (2) of adding an acidic compound; A step (3) of removing a part or all of the alcohol produced as a by-product to prepare an intermediate containing an N-acyl modified product represented by the following formula (7): Step (4) of reacting the intermediate with a polyisocyanate (a4). The method for producing the modified polyisocyanate according to claim 1, comprising: 【Chemistry 5】 In formula (7), R １ and R ２ are the same or different and each is an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8 carbon atoms, n is an integer of 0 to 2, R ７ indicates an alkyl group having 1 to 18 carbon atoms which has no unsaturated group, or a group having 1 to 18 carbon atoms which contains a heteroatom in the alkyl group molecule and has no unsaturated group.

11. The method according to claim 10, wherein the step (3) is carried out by removing some or all of the alcohol produced as a by-product by concentration, without distillation, to prepare an intermediate containing an N-acyl modified product represented by the following formula (7): 【Chemistry 6】 In formula (7), R 1 and R 2 are the same or different and each is an optionally substituted linear or branched alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, alkynyl group, cycloalkynyl group, aryl group or heteroaryl group having 1 to 18 carbon atoms; R 3 is a linear or branched alkylene group having 1 to 8 carbon atoms; n is an integer from 0 to 2; and R 7 is an alkyl group having 1 to 18 carbon atoms that has no unsaturated group, or a group having 1 to 18 carbon atoms that contains a heteroatom in the alkyl molecule and has no unsaturated group.

12. The modified polyisocyanate according to claim 1, wherein the saturated carboxylic acid alkyl ester (a3) ​​is an alkyl ester of a carboxylic acid having a linear structure and two or more hydrogen atoms at the α-position, or an alkyl ester of a branched structure and having two hydrogen atoms at the α-position.

13. The method according to claim 10, wherein the saturated carboxylic acid alkyl ester (a3) ​​is an alkyl ester of a linear carboxylic acid having two or more hydrogen atoms at the α-position.

14. A coating comprising an active hydrogen-containing compound and the modified polyisocyanate according to any one of claims 1 to 9 and 12.

15. 15. The coating of claim 14, wherein the active hydrogen-containing compound comprises an acrylic polyol and / or a bisaspartic acid ester derivative.

16. 15. The coating of claim 14, further comprising at least one member selected from the group consisting of rust inhibitors, catalysts, color pigments, and extender pigments.

17. 15. The coating of claim 14 which is a one-coat paint.

18. A protective coating film obtained by curing the coating according to claim 14.

19. A coated metal material having the protective coating film according to claim 14 formed on a metal substrate.

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