Thermosetting composition

Abstract

To provide a thermosetting composition which has good storage stability and exhibits good low-temperature curability when formed into a resin film.SOLUTION: A thermosetting composition contains a blocked polyisocyanate component, a monohydric or dihydric alcohol compound, and a polyol. The blocked polyisocyanate component contains a blocked polyisocyanate compound having a constituent unit represented by formula (I). In the formula, R11-R13 each independently represent an alkyl group which may contain one or more kinds of substituents selected from the group consisting of a hydroxy group and an amino group; the total number of carbon atoms of R11-R13 is 4 or more and 20 or less; R14-R16 each independently represent a hydrogen atom or an alkyl group which may contain one or more kinds of substituents selected from the group consisting of a hydroxy group and an amino group; and a wavy line represents a bond.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a thermosetting composition. [Background technology]

[0002] Polyurethane resins are known as thermosetting compositions with excellent abrasion resistance, chemical resistance, and stain resistance. Polyurethane resins using polyisocyanates derived from aliphatic or alicyclic diisocyanates have even better weather resistance, and demand for them is increasing. Generally, polyurethane resins consist of two-component thermosetting compositions containing polyol and polyisocyanate, which must be stored separately and mixed before use.

[0003] Furthermore, once mixed, the thermosetting composition gels within a short time and becomes unusable. This makes automated coating extremely difficult in fields where line coating is performed, such as automobiles or low-voltage coating. Furthermore, since isocyanates readily react with water, they cannot be used in water-based coatings such as electrodeposition paints. Furthermore, thorough cleaning of the coating machine and coating tank is required after the end of the work period, reducing work efficiency.

[0004] In order to overcome the above drawbacks, it has been proposed to use blocked polyisocyanates in which all active isocyanate groups are blocked with a blocking agent. This blocked polyisocyanate does not react with polyols at room temperature, but when heated, the blocking agent dissociates, and the active isocyanate groups are regenerated and react with polyols to cause a crosslinking reaction, thereby overcoming the above drawbacks. Many blocking agents have been investigated, and representative examples include phenol and methyl ethyl ketoxime.

[0005] Further, a method has been known in the past in which a blocked polyisocyanate using an active methylene compound such as an acetoacetic ester or a malonic acid diester as a blocking agent is blended into a thermosetting composition (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-070151 [Patent Document 2] International Publication No. 2013 / 151143 Summary of the Invention [Problem to be solved by the invention]

[0007] The thermosetting compositions described in Patent Documents 1 and 2 have room for improvement in terms of improving the low-temperature curing properties when formed into a resin film. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a thermosetting composition that has good storage stability and low-temperature curability when made into a resin film. [Means for solving the problem]

[0008] That is, the present invention includes the following aspects.

[0009] [1] A thermosetting composition comprising a blocked polyisocyanate component, a monohydric or dihydric alcohol compound, and a polyol, wherein the blocked polyisocyanate component comprises a blocked polyisocyanate compound having a structural unit represented by the following general formula (I): A thermosetting composition, wherein the polyol has at least three hydroxy groups in one molecule. [ka] (In general formula (I), R 11 , R 12 and R 13 are each independently an alkyl group which may contain one or more substituents selected from the group consisting of a hydroxy group and an amino group, and R 11 , R 12 and R 13 The total number of carbon atoms in R is 4 or more and 20 or less. 14, R 15 and R 16 are each independently a hydrogen atom or an alkyl group which may contain one or more substituents selected from the group consisting of a hydroxy group and an amino group. The wavy line represents a bond. [2] The thermosetting composition according to [1], wherein the blocked polyisocyanate component comprises a blocked polyisocyanate compound derived from a polyisocyanate derived from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and one or more blocking agents, and the polyisocyanate has an average number of isocyanate groups of 3.5 or more. [3] The thermosetting composition according to [1] or [2], wherein the blocked polyisocyanate compound has a structural unit represented by the following general formula (I-1): [ka] (In general formula (I-1), R 111 , R 112 and R 113 are each independently an alkyl group which may contain one or more substituents selected from the group consisting of a hydroxy group and an amino group. 111 , the R 112 and the above R 113 The total number of carbon atoms in R is 4 or more and 20 or less. 114 and R 115 are each independently a hydrogen atom or an alkyl group which may contain one or more substituents selected from the group consisting of a hydroxy group and an amino group. The wavy line represents a bond. [4] The thermosetting composition according to [1] or [2], wherein the blocked polyisocyanate component contains a blocked polyisocyanate modified with a poly(oxyalkylene) ether represented by the following general formula (III): [ka] (In general formula (III), R 01 is an alkylene group having 1 to 4 carbon atoms, and R 02is a hydroxy group or an alkyl group having 1 to 10 carbon atoms. The average number n1, which indicates the degree of polymerization of the alkylene oxide, is 4 to 30. [5] R in the general formula (I-1) 111 , R 112 , R 113 , R 114 , and R 115 and each independently represent an unsubstituted alkyl group. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a thermosetting composition that has excellent storage stability and low-temperature curing properties when formed into a resin film. DETAILED DESCRIPTION OF THE INVENTION

[0011] <Thermosetting composition> The thermosetting composition of the present invention contains a blocked polyisocyanate component, a monohydric or dihydric alcohol compound, and a polyol.

[0012] <Blocked polyisocyanate component> The blocked polyisocyanate component used in the present invention contains a blocked polyisocyanate compound having a structural unit represented by the following general formula (I): Hereinafter, the structural unit represented by general formula (I) may be referred to as "structural unit (I)."

[0013] Unit The blocked polyisocyanate component used in the present invention has a structural unit (I) represented by the following general formula (I) in the molecule of the blocked polyisocyanate compound contained in the blocked polyisocyanate component.

[0014] [ka]

[0015] In general formula (I), R 11 , R 12 and R13 are each independently an alkyl group which may contain one or more substituents selected from the group consisting of a hydroxy group and an amino group. 11 , R 12 and R 13 The total number of carbon atoms is 4 or more and 20 or less. In general formula (I), R 14 , R 15 and R 16 are each independently a hydrogen atom or an alkyl group which may contain one or more substituents selected from the group consisting of a hydroxy group and an amino group, and the wavy line represents the bonding site with the residue of the polyisocyanate excluding the isocyanate group.

[0016] R 11 , R 12 , R 13 , R 14 , R 15 and R 16 The alkyl group preferably has 1 or more and 20 or less carbon atoms, more preferably 1 or more and 8 or less carbon atoms, further preferably 1 or more and 6 or less carbon atoms, and particularly preferably 1 or more and 4 or less carbon atoms.

[0017] Specific examples of the alkyl group having no substituent include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a sec-butyl group, an isobutyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a tert-pentyl group, a 1-methylbutyl group, an n-hexyl group, a 2-methylpentyl group, a 3-methylpentyl group, a 2,2-dimethylbutyl group, a 2,3-dimethylbutyl group, an n-heptyl group, a 2-methylhexyl group, a 3-methylhexyl group, a 2,2-dimethylpentyl group, a 2,3-dimethylpentyl group, a 2,4-dimethylpentyl group, a 3,3-dimethylpentyl group, a 3-ethylpentyl group, a 2,2,3-trimethylbutyl group, an n-octyl group, an isooctyl group, a 2-ethylhexyl group, a nonyl group, and a decyl group.

[0018] In one embodiment of the present invention, R 11 , R 12 , R 13 , R 14 , R15 and R 16 are each independently an alkyl group having a hydroxy group as a substituent, or an alkyl group having an amino group as a substituent. Examples of the alkyl group containing a hydroxy group as a substituent include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group. Examples of the alkyl group containing an amino group as a substituent include an aminomethyl group, an aminoethyl group, an aminopropyl group, and an aminobutyl group. Examples of the alkyl group containing a hydroxy group and an amino group as a substituent include a hydroxyaminomethyl group, a hydroxyaminoethyl group, and a hydroxyaminopropyl group. Among these, R is preferred because it improves the storage stability when made into a thermosetting composition and the low-temperature curing property when made into a resin film. 11 , R 12 and R 13 are each independently preferably an unsubstituted alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably at least one is an ethyl group.

[0019] In this specification, "low-temperature curing property" is evaluated by the method described in [Evaluation 3] in the Examples below. In the present invention, "excellent low-temperature curing property" means that the curing reaction proceeds sufficiently even under low-temperature heating conditions of 85°C or less.

[0020] R 11 , R 12 and R 13 The total number of carbon atoms is 4 or more and 20 or less, preferably 4 or more and 12 or less, more preferably 4 or more and 9 or less, and particularly preferably 4 or more and 6 or less. R 11 , R 12 and R 13 When the total carbon number is equal to or greater than the lower limit, the aqueous thermosetting composition can exhibit good storage stability, while when the total carbon number is equal to or less than the upper limit, the resin film can exhibit low-temperature curing properties.

[0021] In addition, from the viewpoint of improving low-temperature curing properties when made into a resin film, R 11 , R 12 and R 13 The total number of carbon atoms is preferably 4 or more and 20 or less, more preferably 4 or more and 9 or less, and even more preferably 4.

[0022] R 11 , R 12 and R 13 If the total number of carbon atoms is within the above range, R 11 , R 12 and R 13 The number of carbon atoms in each of the groups is not limited.

[0023] Also, R 14 , R 15 and R 16 R are each independently a hydrogen atom or an alkyl group which may have a substituent. 14 , R 15 and R 16 The alkyl group that may be possessed by the alkyl group is one or more substituents selected from the group consisting of a hydroxy group and an amino group. In one embodiment of the present invention, R 14 , R 15 and R 16 are each preferably an unsubstituted alkyl group having 1 to 4 carbon atoms.

[0024] In one embodiment of the present invention, R 14 , R 15 and R 16 Among R, it is preferable that at least one is a hydrogen atom, and it is more preferable that only one is a hydrogen atom. 14 , R 15 and R 16 When at least one of the groups is a hydrogen atom, the storage stability of the thermosetting composition can be further improved while maintaining low-temperature curing properties when formed into a resin film. In other words, it is more preferable that the structural unit (I) contains a structural unit represented by the following general formula (I-1) (hereinafter, sometimes referred to as structural unit (I-1)):

[0025] [ka]

[0026] In the general formula (I-1), R 111 , R 112 , and R 113 is R in the general formula (I). 11 , R 12 , and R 13 In the general formula (I-1), R 114 and R 115 is R in the general formula (I). 14 , R 15 , and R 16 The wavy lines represent the bonding sites with the residues of the polyisocyanate excluding the isocyanate groups.

[0027] The molar ratio of the structural unit (I-1) in the structural unit (I) (structural unit (I-1) / structural unit (I)) is preferably 10 mol% or more, more preferably 30 mol% or more, even more preferably 50 mol% or more, particularly preferably 60 mol% or more, and most preferably 70 mol% or more.

[0028] [Constituent Unit (II)] The molecule of the blocked polyisocyanate compound contained in the blocked polyisocyanate component may further contain a structural unit represented by the following general formula (II) (hereinafter, sometimes referred to as structural unit (II)).

[0029] [ka]

[0030] In the general formula (II), R 21 , R 22 , R 23 and R 24 are each independently a hydrogen atom or an alkyl group which may contain one or more substituents selected from the group consisting of a hydroxy group and an amino group, and the wavy line represents the bonding site with the residue of the polyisocyanate excluding the isocyanate group. R 21 , R 22 , R 23 and R 24 The alkyl group which may have one or more substituents selected from the group consisting of a hydroxy group and an amino group in the above formula "R 11 , R 12 , R 13 , R 14 , R 15 and R 16 " are examples of the same.

[0031] Among them, R 21 , R 22 , R 23 and R 24 As R, a hydrogen atom or an unsubstituted alkyl group having 1 to 4 carbon atoms is preferred in terms of excellent storage stability, and a hydrogen atom, a methyl group, or an ethyl group is more preferred in terms of excellent low-temperature curing properties when formed into a resin film. 21 , R 22 , R 23 and R 24 is more preferably a methyl group or an ethyl group.

[0032] R 21 , R 22 , R 23 and R 24 When all of R are methyl groups, the two ester moieties of the malonic acid ester of the structural unit (II) are both isopropyl groups. 21 and R 22 one of which is a hydrogen atom and the other is a methyl group, and R 23 and R 24 When one of R is a hydrogen atom and the other is a methyl group, the two ester moieties of the malonic acid ester of the structural unit (II) are both ethyl groups. 21 , R 22 , R 23 and R 24 are all methyl groups, that is, the two ester moieties of the malonic acid ester of the structural unit (II) are both isopropyl groups.

[0033] The molar ratio of the structural unit represented by general formula (II) to the structural unit represented by general formula (I) (structural unit (II) / structural unit (I)) is preferably 1 / 99 or more and 96 / 4 or less, more preferably 5 / 95 or more and 95 / 5 or less, even more preferably 7 / 93 or more and 93 / 7 or less, even more preferably 10 / 90 or more and 90 / 10 or less, even more preferably 20 / 80 or more and 85 / 15 or less, even more preferably 30 / 70 or more and 85 / 15 or less, particularly preferably 35 / 65 or more and 85 / 15 or less, and most preferably 50 / 50 or more and 70 / 30 or less. By having this molar ratio be equal to or less than the upper limit, the storage stability of the thermosetting composition can be improved. Furthermore, by having this molar ratio be equal to or greater than the lower limit, the low-temperature curing properties of the resin film can be improved.

[0034] The molar ratio of the structural unit (II) to the structural unit (I) can be determined, for example, by converting the thermosetting composition into 1 H-NMR and 13 It can be calculated by measuring the composition ratio of the structural unit (II) to the structural unit (I) by C-NMR.

[0035] In general formula (I), a blocked polyisocyanate component in which at least one ester group in the diester moiety is a tert-butyl group is known to have excellent curing properties with a polyhydroxy compound at low temperatures of around 85°C. However, in an aqueous thermosetting composition, the blocked polyisocyanate component has high reactivity with water, and when the blocked polyisocyanate component is blended into an aqueous thermosetting composition and stored as an aqueous thermosetting composition containing a polyhydroxy compound, a curing agent, and water, the blocked polyisocyanate component is prone to increase in viscosity and gelation.

[0036] R in structural unit (I) 11 , R 12 and R 13 By making the total number of carbon atoms between 4 and 20, viscosity increase and gelation during storage can be effectively suppressed, and good storage stability can be achieved. At the same time, a resin film with excellent curing properties at low temperatures of 85°C or less can be obtained.

[0037] The blocked polyisocyanate component used in the present invention may be a blocked polyisocyanate in which at least some of the isocyanate groups in the molecule are blocked with a malonic acid ester having a secondary alkyl group or a malonic acid ester having a primary alkyl group and a malonic acid ester having a tertiary alkyl group. Alternatively, the blocked polyisocyanate may be a blocked polyisocyanate in which at least some of the isocyanate groups in the polyisocyanate are blocked with a malonic acid ester having a secondary alkyl group, or a mixture of a blocked polyisocyanate in which at least some of the isocyanate groups in the polyisocyanate are blocked with a malonic acid ester having a primary alkyl group and a blocked polyisocyanate in which at least some of the isocyanate groups in the polyisocyanate are blocked with a malonic acid ester having a tertiary alkyl group.

[0038] [Other functional groups] The blocked polyisocyanate component may have one or more functional groups selected from the group consisting of an allophanate group, a uretdione group, an iminooxadiazinedione group, an isocyanurate group, a urethane group, and a biuret group. Among these, an isocyanurate group is preferred because it provides excellent weather resistance.

[0039] [Polyisocyanate] (Isocyanate) The polyisocyanate used in producing the blocked polyisocyanate component is a reaction product obtained by reacting multiple monomer compounds having one or more isocyanate groups (-NCO) (hereinafter, sometimes referred to as "isocyanate monomers").

[0040] The isocyanate monomer preferably has 4 to 30 carbon atoms. Specific examples of the isocyanate monomer include the following. These isocyanate monomers may be used alone or in combination of two or more.

[0041] (1) Aromatic diisocyanates such as diphenylmethane-4,4'-diisocyanate (MDI), 1,5-naphthalene diisocyanate, tolylene diisocyanate (TDI), xylylene diisocyanate, and m-tetramethylxylylene diisocyanate (TMXDI). (2) Aliphatic diisocyanates such as 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (hereinafter sometimes referred to as "HDI"), 2,2,4-trimethyl-1,6-diisocyanatohexane, 2,4,4-trimethyl-1,6-hexamethylene diisocyanate, 2-methylpentane-1,5-diisocyanate (MPDI), and lysine diisocyanate (hereinafter sometimes referred to as "LDI").

[0042] (3) Alicyclic diisocyanates such as isophorone diisocyanate (hereinafter sometimes referred to as "IPDI"), 1,3-bis(diisocyanatemethyl)cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, diisocyanate norbornane, and di(isocyanatemethyl)norbornane. (4) Triisocyanates such as 4-isocyanatomethyl-1,8-octamethylene diisocyanate (hereinafter sometimes referred to as "NTI"), 1,3,6-hexamethylene triisocyanate (hereinafter sometimes referred to as "HTI"), bis(2-isocyanatoethyl) 2-isocyanatoglutarate (hereinafter sometimes referred to as "GTI"), and lysine triisocyanate (hereinafter sometimes referred to as "LTI").

[0043] The isocyanate monomer used in producing the polyisocyanate is preferably one or more diisocyanate monomers selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates because they provide excellent weather resistance when formed into a resin film, more preferably HDI or IPDI because they are easily available industrially, and even more preferably HDI because it provides a low viscosity to the blocked polyisocyanate component. Furthermore, as the isocyanate monomer used in the production of polyisocyanate, diisocyanate monomers other than the above-mentioned aliphatic diisocyanates and alicyclic diisocyanates may also be used.

[0044] The polyisocyanate preferably has an isocyanurate group, and may have, in addition to the isocyanurate group, one or more functional groups selected from the group consisting of an allophanate group, a uretdione group, an iminooxadiazinedione group, an isocyanurate group, a urethane group, and a biuret group.

[0045] (Polyol) The polyisocyanate used to produce the blocked polyisocyanate component is preferably derived from the above-mentioned diisocyanate and a polyol having an average functionality of 3.0 to 8.0. This allows the average number of isocyanate groups in the polyisocyanate to be increased. In the polyisocyanate, urethane groups are formed by the reaction between the hydroxyl groups of the polyol and the isocyanate groups of the diisocyanate monomer.

[0046] The average number of functional groups of the polyol used in producing the blocked polyisocyanate component is preferably 3.0 or more and 8.0 or less, more preferably 3 or more and 6 or less, even more preferably 3 or more and 5 or less, and particularly preferably 3 or 4. The average number of functional groups of the polyol referred to here is the number of hydroxyl groups present in one molecule of the polyol.

[0047] The number average molecular weight of the polyol used in producing the blocked polyisocyanate component is preferably 100 or more and 1,000 or less, preferably 100 or more and 900 or less, more preferably 100 or more and 600 or less, more preferably 100 or more and 570 or less, even more preferably 100 or more and 500 or less, still more preferably 100 or more and 400 or less, particularly preferably 100 or more and 350 or less, and most preferably 100 or more and 250 or less, from the viewpoint of improving the coating hardness and strength. When the number-average molecular weight of the polyol is within the above range, the thermosetting composition has excellent low-temperature curing properties when formed into a resin film, and is particularly excellent in hardness and strength. The number-average molecular weight Mn of the polyol is, for example, the number-average molecular weight measured by GPC using polystyrene as the standard.

[0048] Examples of such polyols include trimethylolpropane, glycerol, and polycaprolactone polyols derived from trihydric or higher polyhydric alcohols and ε-caprolactone. Commercially available polycaprolactone polyols include Daicel Corporation's "Placcel 303" (number average molecular weight 300), "Placcel 305" (number average molecular weight 550), "Placcel 308" (number average molecular weight 850), and "Placcel 309" (number average molecular weight 900).

[0049] (Production of polyisocyanates) The method for producing polyisocyanate will be described in detail below. Polyisocyanates can be obtained, for example, by simultaneously carrying out an allophanate reaction to form allophanate groups, a uretdione reaction to form uretdione groups, an iminooxadiazinedione reaction to form iminooxadiazinedione groups, an isocyanurate reaction to form isocyanurate groups, a urethanization reaction to form urethane groups, and a biuret reaction to form biuret groups in the presence of an excess of isocyanate monomer, and then removing the unreacted isocyanate monomer after the completion of the reactions. That is, the polyisocyanate obtained by the above reaction is a reaction product in which a plurality of the above-mentioned isocyanate monomers are bonded together and has one or more groups selected from the group consisting of allophanate groups, uretdione groups, iminooxadiazinedione groups, isocyanurate groups, urethane groups, and biuret groups.

[0050] Alternatively, the above reactions may be carried out separately and the resulting polyisocyanates may be mixed in a specific ratio. From the viewpoint of ease of production, it is preferable to carry out the above reaction at one time to obtain a polyisocyanate, but from the viewpoint of freely adjusting the molar ratio of each functional group, it is preferable to produce them separately and then mix them.

[0051] Furthermore, an antioxidant or an ultraviolet absorber may be added to the obtained polyisocyanate, for example, for the purpose of suppressing coloration during storage. Examples of antioxidants include hindered phenols such as 2,6-di-tert-butyl-p-cresol. Examples of ultraviolet absorbers include benzotriazole and benzophenone. These antioxidants and ultraviolet absorbers may be used alone or in combination of two or more. The amount of these added is preferably 10 ppm by mass or more and 500 ppm by mass or less relative to the mass of the polyisocyanate.

[0052] (average number of isocyanate groups in polyisocyanate) From the viewpoint of improving the low-temperature curing property when formed into a resin film, the average number of isocyanate groups in the polyisocyanate is preferably 2 or more, and from the viewpoint of achieving both the low-temperature curing property when formed into a resin film and compatibility with the polyvalent hydroxy compound, the average number of isocyanate groups is preferably 3 or more, more preferably 3.2 or more, even more preferably 3.5 or more, particularly preferably 3.8 or more, and most preferably 4.0 or more. Furthermore, from the viewpoint of achieving both low-temperature curing properties when formed into a resin film and compatibility with polyvalent hydroxy compounds, the average number of isocyanate groups in the polyisocyanate is preferably 20 or less, more preferably 10 or less, even more preferably 8 or less, particularly preferably 7 or less, and most preferably 6 or less. The above upper and lower limits for the average number of isocyanate groups in the polyisocyanate can be combined in any desired manner. The average number of isocyanate groups in the polyisocyanate is, for example, 3 or more and 20 or less, 3.2 or more and 10 or less, 3.5 or more and 8 or less, 3.8 or more and 7 or less, or 4.0 or more and 6 or less.

[0053] The average number of isocyanate groups in a polyisocyanate can be calculated, for example, from the number average molecular weight Mn and the isocyanate group content (NCO content) of the polyisocyanate using the following formula: Average number of isocyanate groups = (Mn of polyisocyanate × NCO content × 0.01) / 42

[0054] [Blocking agent] The blocking agent used in producing the blocked polyisocyanate component preferably contains a malonic acid ester having a secondary alkyl group or a malonic acid ester having a primary alkyl group, and a malonic acid ester having a tertiary alkyl group, and more preferably contains a malonic acid ester having a secondary alkyl group and a malonic acid ester having a tertiary alkyl group. The blocking agent may contain one type of each of the malonic acid ester having a secondary alkyl group, the malonic acid ester having a primary alkyl group, and the malonic acid ester having a tertiary alkyl group, or a combination of two or more types.

[0055] The malonic acid ester having a primary alkyl group is not particularly limited, and examples thereof include dimethyl malonate, diethyl malonate, dipropyl malonate, dibutyl malonate, dicyclohexyl malonate, diphenyl malonate, etc. Among these, diethyl malonate is preferred as the malonic acid ester having a primary alkyl group.

[0056] The malonic acid ester having a secondary alkyl group is not particularly limited, but examples thereof include di-sec-butyl malonate, diisopropyl malonate, isopropylethyl malonate, etc. Among these, diisopropyl malonate is preferred as the malonic acid ester having a secondary alkyl group.

[0057] Malonic acid esters having a tertiary alkyl group are not particularly limited, and examples thereof include di-tert-butyl malonate, di(2-methyl-2-butyl) malonate, di(2-methyl-2-pentyl) malonate, (tert-butyl)ethyl malonate, (2-methyl-2-butyl)ethyl malonate, (2-methyl-2-butyl)isopropyl malonate, (2-methyl-2-pentyl)ethyl malonate, (2-methyl-2-pentyl)isopropyl malonate, and (2-methyl-2-pentyl)hexylisopropyl malonate.

[0058] Among these, di(2-methyl-2-butyl) malonate, di(2-methyl-2-pentyl) malonate, (2-methyl-2-butyl) isopropyl malonate, (2-methyl-2-pentyl) ethyl malonate, and (2-methyl-2-pentyl) isopropyl malonate are preferred, and (2-methyl-2-butyl) ethyl malonate, (2-methyl-2-butyl) isopropyl malonate, (2-methyl-2-pentyl) ethyl malonate, and (2-methyl-2-pentyl) hexyl isopropyl malonate are preferred, or di-tert-butyl malonate, (2-methyl-2-butyl) isopropyl malonate, or (2-methyl-2-pentyl) isopropyl malonate are preferred.

[0059] The malonic acid ester having a tertiary alkyl group may be a commercially available product, or may be synthesized by the method described in Reference Document 1 (JP-A-11-130728).

[0060] (Other blocking agents) The blocking agent used in producing the blocked polyisocyanate component may further contain other blocking agents in addition to the malonic acid ester having a secondary alkyl group and the malonic acid ester having a tertiary alkyl group, as long as the other blocking agents do not impair the storage stability of a resin composition formed therefrom or the low-temperature curing properties of a resin film formed therefrom.

[0061] Other blocking agents include 1) alcohol-based compounds, 2) alkylphenol-based compounds, 3) phenol-based compounds, 4) active methylene-based compounds other than malonic acid esters having a secondary alkyl group and malonic acid esters having a tertiary alkyl group, 5) mercaptan-based compounds, 6) acid amide-based compounds, 7) acid imide-based compounds, 8) imidazole-based compounds, 9) urea-based compounds, 10) oxime-based compounds, 11) amine-based compounds, 12) imide-based compounds, 13) bisulfites, 14) pyrazole-based compounds, and 15) triazole-based compounds.

[0062] [Poly(oxyalkylene) ether] The blocked polyisocyanate component is preferably modified with a poly(oxyalkylene) ether to prevent the viscosity of the thermosetting composition from increasing during storage. The poly(oxyalkylene) ether is a compound represented by the following general formula (III) (hereinafter, sometimes referred to as "compound (III)").

[0063] [ka]

[0064] In the general formula (III), R 01 is an alkylene group having 1 to 4 carbon atoms, and R 02 is a hydroxy group or an alkyl group having 1 to 10 carbon atoms. The average number n1 indicating the degree of polymerization of the alkylene oxide (hereinafter, may be referred to as "degree of polymerization n1" or simply "n1") is 4 to 30.

[0065] ·R 01 In general formula (I), R 01 is an alkylene group having 1 to 4 carbon atoms, and is preferably an ethylene group or a propylene group from the viewpoint of making it difficult for the viscosity of the thermosetting composition to increase during storage.

[0066] ·R 02 In general formula (I), R 02is a hydroxy group or an alkyl group having from 1 to 10 carbon atoms, and from the viewpoint of achieving excellent resin hardness when the thermosetting composition is cured, is preferably a hydroxy group or an alkyl group having from 1 to 8 carbon atoms, more preferably an alkyl group having from 1 to 6 carbon atoms.

[0067] n1 The average number n1 is preferably 4.0 or more, more preferably 6.0 or more, and even more preferably 7.5 or more, from the viewpoint of making it difficult for the viscosity of the thermosetting composition to increase during storage. On the other hand, the average number of n1 is preferably 30 or less, more preferably 28 or less, and even more preferably 26 or less, from the viewpoint of excellent resin hardness when the thermosetting composition is cured.

[0068] Commercially available poly(oxyalkylene) ethers include those manufactured by NOF Corporation under the trade names "UNIOX M400," "UNIOX M550," "UNIOX M1000," and "UNIOX M2000," those manufactured by Nippon Nyukazai Co., Ltd. under the trade names "MPG-081," "MPG-130," and "TN-555," those manufactured by AGC under the trade names "EXCENOL 420," "EXCENOL 720," and "EXCENOL 1020," and those manufactured by Mitsubishi Chemical Corporation under the trade names "PTMG650," "PTMG1000," and "PTMG2000."

[0069] From the viewpoint of making it difficult for the viscosity of the thermosetting composition to increase during storage, the lower limit of the amount of the structural units derived from the poly(oxyalkylene) ether is preferably 0.1 mass%, more preferably 0.15 mass%, even more preferably 0.2 mass%, and particularly preferably 0.25 mass%, relative to the mass of the solid content of the blocked polyisocyanate component.

[0070] Furthermore, from the viewpoint of achieving excellent resin hardness when formed into a resin film, the upper limit of the amount of structural units derived from poly(oxyalkylene) ether is preferably 55 mass%, more preferably 50 mass%, even more preferably 48 mass%, and particularly preferably 44 mass%, relative to the mass of the solid content of the blocked polyisocyanate component. That is, the content of the poly(oxyalkylene) ether is preferably 0.1% by mass or more and 55% by mass or less, more preferably 0.15% by mass or more and 50% by mass or less, even more preferably 0.20% by mass or more and 48% by mass or less, and particularly preferably 0.25% by mass or more and 44% by mass or less, relative to the mass of the solid content of the blocked polyisocyanate component.

[0071] From the viewpoint of making it difficult for the viscosity of the thermosetting composition to increase during storage and from the viewpoint of achieving excellent resin hardness when the thermosetting composition is cured, the molar ratio of the poly(oxyalkylene) ether relative to 100 mol% of isocyanate groups in the raw material polyisocyanate is preferably from 0.05 mol% to 40 mol%, more preferably from 0.10 mol% to 38 mol%, even more preferably from 0.10 mol% to 36 mol%, particularly preferably from 0.10 mol% to 34 mol%, and most preferably from 0.15 mol% to 30 mol%.

[0072] [Ionic hydrophilic compounds] The blocked polyisocyanate contained in the blocked polyisocyanate component may have a portion of its isocyanate groups modified with an ionic hydrophilic compound, i.e., the blocked polyisocyanate may have a structural unit derived from an ionic hydrophilic compound introduced into a portion of its isocyanate groups.

[0073] The ionic hydrophilic compound is a compound having a hydrophilic group. In addition to the hydrophilic group, the ionic hydrophilic compound preferably has one or more active hydrogen groups per molecule of the hydrophilic compound, which are capable of reacting with at least one isocyanate group of the polyisocyanate. Specific examples of the active hydrogen group include a hydroxyl group, a mercapto group, a carboxylic acid group, an amino group, and a thiol group.

[0074] Examples of the ionic hydrophilic compound include cationic compounds and anionic compounds. These hydrophilic compounds may be used alone or in combination of two or more. Among them, anionic compounds are preferred as the ionic hydrophilic compound, since the hardness of the resulting resin film is less likely to decrease.

[0075] (cationic compounds) Specific examples of cationic compounds contained in the blocked polyisocyanate component include compounds having both a cationic hydrophilic group and an active hydrogen group. Alternatively, a compound having an active hydrogen group such as a glycidyl group may be combined with a compound having a cationic hydrophilic group such as a sulfide or phosphine to form a hydrophilic compound. In this case, a compound having an isocyanate group and a compound having an active hydrogen group are reacted in advance to add a functional group such as a glycidyl group, and then a compound such as a sulfide or phosphine is reacted. From the viewpoint of ease of production, a compound having both a cationic hydrophilic group and an active hydrogen group is preferred.

[0076] Specific examples of compounds having both a cationic hydrophilic group and an active hydrogen group include dimethylethanolamine, diethylethanolamine, diethanolamine, methyldiethanolamine, etc. Tertiary amino groups added using these compounds can also be quaternized with, for example, dimethyl sulfate or diethyl sulfate.

[0077] The reaction between the cationic compound and the alicyclic polyisocyanate can be carried out in the presence of a solvent. In this case, the solvent is preferably one that does not contain an active hydrogen group, and specific examples thereof include ethyl acetate, propylene glycol monomethyl ether acetate, and dipropylene glycol dimethyl ether.

[0078] The cationic hydrophilic groups added to the blocked polyisocyanate are preferably neutralized with a compound having an anionic group, such as a carboxy group, a sulfonic acid group, a phosphate group, a halogen group, or a sulfate group. Specific examples of compounds having a carboxyl group include formic acid, acetic acid, propionic acid, butyric acid, and lactic acid. Specific examples of compounds having a sulfonic acid group include ethanesulfonic acid. Specific examples of compounds having a phosphate group include phosphoric acid and acidic phosphate esters. Specific examples of compounds having a halogen group include hydrochloric acid. Specific examples of compounds having a sulfate group include sulfuric acid. Among these, compounds having an anionic group are preferably compounds having a carboxy group, and more preferably acetic acid, propionic acid or butyric acid.

[0079] (anionic compounds) Specific examples of the anionic hydrophilic group contained in the blocked polyisocyanate component include a carboxy group, a sulfonic acid group, a phosphoric acid group, a halogen group, and a sulfate group. Specific examples of the anionic compound include compounds having both an anionic group and an active hydrogen group, and more specific examples include compounds having a carboxy group of a monohydroxycarboxylic acid or polyhydroxycarboxylic acid as the anionic group. Examples of monohydroxycarboxylic acids include 1-hydroxyacetic acid, 3-hydroxypropanoic acid, 12-hydroxy-9-octadecanoic acid, hydroxypivalic acid, and lactic acid. Examples of compounds having a carboxy group of a polyhydroxycarboxylic acid as an anionic group include dimethylolacetic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolpentanoic acid, dihydroxysuccinic acid, and dimethylolpropionic acid. Further, compounds having both a sulfonic acid group and an active hydrogen group are also included, and more specifically, isethionic acid is included. Among these, hydroxypivalic acid or dimethylolpropionic acid is preferred as a compound having both an anionic group and an active hydrogen group.

[0080] The anionic hydrophilic group added to the blocked polyisocyanate is preferably neutralized with an amine compound, which is a basic substance. Specific examples of the amine compound include ammonia and water-soluble amino compounds. Specific examples of water-soluble amino compounds include monoethanolamine, ethylamine, dimethylamine, diethylamine, triethylamine, propylamine, dipropylamine, isopropylamine, diisopropylamine, triethanolamine, butylamine, dibutylamine, 2-ethylhexylamine, ethylenediamine, propylenediamine, methylethanolamine, dimethylethanolamine, diethylethanolamine, and morpholine. Tertiary amines such as triethylamine and dimethylethanolamine can also be used. These amine compounds may be used alone or in combination of two or more.

[0081] (Other components) The blocked polyisocyanate component may further contain additives such as a solvent in addition to the blocked polyisocyanate. The solvents include 1-methylpyrrolidone, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether, 3-methoxy-3-methyl-1-butanol, ethylene glycol diethyl ether, diethylene glycol diethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether (DPDM), propylene glycol dimethyl ether, methyl ethyl ketone, acetone, Examples of suitable solvents include methyl isobutyl ketone, propylene glycol monomethyl ether acetate, ethanol, methanol, isopropanol, 1-propanol, isobutanol, 1-butanol, tert-butanol, 2-ethylhexanol, cyclohexanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, ethyl acetate, isopropyl acetate, butyl acetate, toluene, xylene, pentane, isopentane, hexane, isohexane, cyclohexane, solvent naphtha, and mineral spirits. These solvents may be used alone or in combination of two or more. From the viewpoint of water dispersibility, the solvent preferably has a solubility in water of 5% by mass or more, and specifically, DPDM is preferred.

[0082] [Method for producing blocked polyisocyanate component] The method for producing the blocked polyisocyanate component is not particularly limited, but the following two methods can be mentioned. 1) A method of reacting the polyisocyanate with the malonic acid ester having a tertiary alkyl group, and the malonic acid ester having a secondary alkyl group or the malonic acid ester having a primary alkyl group. 2) A method in which the polyisocyanate is reacted with at least one blocking agent selected from the group consisting of the malonic acid ester having a tertiary alkyl group, the malonic acid ester having a secondary alkyl group, and the malonic acid ester having a primary alkyl group, and an alcohol having a chain alkyl group is added to the resulting reaction product to introduce an alkyl group derived from the alcohol by transesterification of the terminal ester moiety of the reaction product.

[0083] Of the two methods above, method 2) is preferred, taking into consideration the ease of the process and the ease of controlling the molar ratio of structural unit (II) / structural unit (I).

[0084] The blocking reaction between the polyisocyanate and the blocking agent can be carried out regardless of the presence or absence of a solvent, and a blocked polyisocyanate is obtained. The blocking agent may be one of a malonic acid ester having a primary alkyl group, a malonic acid ester having a secondary alkyl group, and a malonic acid ester having a tertiary alkyl group, or two or more of them may be used in combination. The amount of the blocking agent added may usually be 80 mol % or more and 200 mol % or less, and preferably 90 mol % or more and 150 mol % or less, based on the total molar amount of isocyanate groups.

[0085] When a solvent is used, it is sufficient to use a solvent that is inactive to isocyanate groups. When a solvent is used, the content of non-volatile components derived from the polyisocyanate and the blocking agent relative to 100 parts by mass of the thermosetting composition may usually be 10 parts by mass or more and 95 parts by mass or less, preferably 15 parts by mass or more and 80 parts by mass or less, and more preferably 20 parts by mass or more and 75 parts by mass or less.

[0086] In the blocking reaction, organic metal salts of tin, zinc, lead, etc., tertiary amine compounds, alcoholates of alkali metals such as sodium, etc., may be used as catalysts. The amount of catalyst added varies depending on the temperature of the blocking reaction, etc., but is usually from 0.05 to 1.5 parts by mass, preferably from 0.1 to 1.0 part by mass, per 100 parts by mass of polyisocyanate.

[0087] The blocking reaction can generally be carried out at a temperature of from -20°C to 150°C, preferably from 0°C to 100°C, and more preferably from 10°C to 80°C. When the temperature of the blocking reaction is equal to or higher than the lower limit, the reaction rate can be further increased. When the temperature of the blocking reaction is equal to or lower than the upper limit, side reactions can be further suppressed.

[0088] After the blocking reaction, a neutralization treatment may be carried out by adding an acidic compound or the like. The acidic compound may be an inorganic acid or an organic acid. Examples of inorganic acids include hydrochloric acid, phosphorous acid, and phosphoric acid. Examples of organic acids include methanesulfonic acid, p-toluenesulfonic acid, dioctyl phthalate, and dibutyl phthalate.

[0089] When the polyisocyanate is produced by the above method 2), the blocking reaction is followed by an ester exchange reaction. As the alcohol having a chain alkyl group used in the transesterification reaction in method 2), the same alcohols as those in the first embodiment can be used. The chain alkyl group of the alcohol may be the same as or different from that of the blocking agent. When the chain alkyl group is different from that of the blocking agent, it is preferable to use a monoalcohol having a chain alkyl group with a different number of alkyl substitutions than that of the blocking agent. Specifically, for example, when a single malonic acid ester having a secondary alkyl group is used as the blocking agent, a monoalcohol having a tertiary alkyl group can be used.

[0090] In the case of producing by the method 2), it is preferable to remove the generated alcohol or the residual added alcohol during or after the transesterification reaction by distillation under normal pressure or reduced pressure. Among these, in order to efficiently proceed with the transesterification reaction, it is preferable to remove the generated alcohol by performing an operation such as distillation during the transesterification reaction. In this case, in order to efficiently remove the alcohol component generated by the transesterification reaction, it is more preferable that the alcohol component to be added has a boiling point higher than that of the generated alcohol component.

[0091] The transesterification reaction can generally be carried out at a temperature of 0°C or higher and 150°C or lower, preferably 30°C or higher and 120°C or lower, and more preferably 50°C or higher and 100°C or lower. When the temperature of the transesterification reaction is equal to or higher than the lower limit, the reaction rate can be further increased. Furthermore, when the temperature of the transesterification reaction is equal to or lower than the upper limit, side reactions can be further suppressed.

[0092] The molar ratio of the structural unit (II) to the structural unit (I) can be controlled by adjusting the molar ratio of the alcohol added to the blocked isocyanate group, or by adjusting the transesterification reaction temperature and transesterification reaction time, or by distilling off the generated alcohol, etc.

[0093] When a hydrophilic compound is used, the polyisocyanate, the active hydrogen compound, the blocking agent and the hydrophilic compound may be reacted with each other.

[0094] The reaction between the polyisocyanate and the active hydrogen compound, the reaction between the polyisocyanate and the hydrophilic compound, and the reaction between the polyisocyanate and the blocking agent can be carried out simultaneously, or one of the reactions can be carried out in advance before the second or subsequent reaction. It is particularly preferred to carry out the reaction between the polyisocyanate and the hydrophilic compound first to obtain a hydrophilic compound-modified polyisocyanate modified with the hydrophilic compound, and then to react the obtained hydrophilic compound-modified polyisocyanate with an active hydrogen compound or a blocking agent simultaneously or sequentially. Either the reaction between the hydrophilic compound-modified polyisocyanate and the active hydrogen compound or the reaction between the hydrophilic compound-modified polyisocyanate and the blocking agent can be carried out first.

[0095] The reaction between polyisocyanate and hydrophilic compound may be carried out using an organic metal salt, a tertiary amine compound, or an alcoholate of an alkali metal as a catalyst. Examples of the metal constituting the organic metal salt include tin, zinc, and lead. Examples of the alkali metal include sodium.

[0096] The reaction temperature between the polyisocyanate and the hydrophilic compound is preferably −20° C. or higher and 150° C. or lower, and more preferably 30° C. or higher and 130° C. or lower. When the reaction temperature is equal to or higher than the lower limit, reactivity tends to be increased. Furthermore, when the reaction temperature is equal to or lower than the upper limit, side reactions tend to be more effectively suppressed. It is preferable to completely react the hydrophilic compound with the polyisocyanate so that no unreacted hydrophilic compound remains, which tends to more effectively prevent deterioration in the aqueous dispersion stability of the thermosetting composition and the low-temperature curing properties of the resin film formed therefrom.

[0097] The reaction between the hydrophilic compound-modified polyisocyanate and the active hydrogen compound, and the reaction between the hydrophilic compound-modified polyisocyanate and the blocking agent can be carried out using the methods described above for the active hydrogen compound modification reaction and the blocking reaction.

[0098] <Monohydric or dihydric alcohol compounds> The thermosetting composition of the present embodiment contains a monohydric or dihydric alcohol compound.

[0099] (monohydric alcohol compounds) The monohydric alcohol compound is not particularly limited, but examples thereof include aliphatic, alicyclic, and aromatic monohydric alcohol compounds, and among these, aliphatic monohydric alcohol compounds are preferred.The aliphatic monohydric alcohol compound is not particularly limited, but more preferred is a monohydric alcohol compound having 1 to 20 carbon atoms.

[0100] The monohydric alcohol compound having 1 to 20 carbon atoms is not particularly limited, but examples thereof include saturated alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, tert-butanol, 2-ethyl-1-propanol, n-amyl alcohol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-2-butanol, and 2,2-dimethyl-1-propanol; ether alcohols such as 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, and 3,6-dioxa-1-heptanol; and amino alcohols such as N,N-dimethylaminoethanol and 3-amino-1-propanol.

[0101] (dihydric alcohol compounds) The dihydric alcohol compound is not particularly limited, but examples thereof include aliphatic, alicyclic, and aromatic monohydric alcohol compounds, and among these, aliphatic dihydric alcohol compounds are preferred.The aliphatic dihydric alcohol compound is not particularly limited, but more preferred is a dihydric alcohol compound having 1 to 10 carbon atoms.

[0102] The dihydric alcohol compound having 1 to 10 carbon atoms is not particularly limited, and examples thereof include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,3-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-1,3-propanediol, 2-ethyl-2-methyl-1,3-propanediol, and 2-methyl-2-methyl-1,3-propanediol. 1,4-butanediol, 2-methyl-2,4-pentanediol, 1,4-pentanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,6-hexanediol, 2-methyl-1,8-octanediol; ether alcohols such as diethylene glycol and dipropylene glycol; and amino alcohols such as N-methyldiethanolamine.

[0103] The molar ratio of the alcohol compound to the blocked isocyanate group contained in the thermosetting composition is preferably 0.2 or more and 20 or less. The lower limit of this molar ratio is more preferably 0.4, even more preferably 0.7, and particularly preferably 1.0. The upper limit of this molar ratio is more preferably 15.0, even more preferably 13.0, and particularly preferably 10.0. A molar ratio of 0.2 or more tends to ensure storage stability when formed into a one-component thermosetting composition, and a molar ratio of 20 or less tends to prevent a decrease in curability after storage.

[0104] <Polyol> The polyol contained in the thermosetting composition means a compound having at least three hydroxyl groups in one molecule. Specific examples of the polyol include aliphatic hydrocarbon polyols, polyether polyols, polyester polyols, epoxy resins, fluorine-containing polyols, and acrylic polyols, with acrylic polyols being preferred.

[0105] [Aliphatic hydrocarbon polyols] Examples of the aliphatic hydrocarbon polyols include hydroxyl-terminated polybutadiene and its hydrogenated products.

[0106] [Polyether polyols] Examples of polyether polyols include those obtained by any of the following methods (1) to (3). (1) Polyether polyols or polytetramethylene glycols obtained by adding alkylene oxides, either singly or in mixture, to polyhydric alcohols, either singly or in mixture. (2) Polyether polyols obtained by reacting alkylene oxide with a polyfunctional compound. (3) Polymer polyols obtained by polymerizing acrylamide or the like using the polyether polyols obtained in (1) or (2) as a medium.

[0107] Examples of the polyhydric alcohol in (1) above include glycerin and propylene glycol. Examples of the alkylene oxide in (2) above include ethylene oxide and propylene oxide. Examples of the polyfunctional compound in (2) above include ethylenediamine and ethanolamines.

[0108] [Polyester polyols] Examples of the polyester polyols include the following polyester polyols (1A) and (2A). (1A) Polyester polyol resins obtained by a condensation reaction between a dibasic acid alone or a mixture of two or more kinds and a polyhydric alcohol alone or a mixture of two or more kinds. (2A) Polycaprolactones obtained by ring-opening polymerization of ε-caprolactone with polyhydric alcohols.

[0109] Examples of the dibasic acid include carboxylic acids such as succinic acid, adipic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, and 1,4-cyclohexanedicarboxylic acid.

[0110] Examples of the polyhydric alcohol in (1A) above include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, trimethylpentanediol, cyclohexanediol, trimethylolpropane, glycerin, pentaerythritol, 2-methylolpropanediol, and ethoxylated trimethylolpropane.

[0111] [Epoxy resins] Examples of epoxy resins include novolac-type epoxy resins, β-methylepicro-type epoxy resins, cyclic oxirane-type epoxy resins, glycidyl ether-type epoxy resins, glycol ether-type epoxy resins, epoxy-type aliphatic unsaturated compounds, epoxidized fatty acid esters, ester-type polycarboxylic acids, aminoglycidyl-type epoxy resins, halogenated epoxy resins, and resorcinol-type epoxy resins, as well as resins obtained by modifying these epoxy resins with amino compounds, polyamide compounds, or the like.

[0112] [Fluorine-containing polyols] Examples of fluorine-containing polyols include copolymers of fluoroolefins, cyclohexyl vinyl ethers, hydroxyalkyl vinyl ethers, and monocarboxylic acid vinyl esters, which are disclosed in Reference Document 1 (JP-A-57-34107) and Reference Document 2 (JP-A-61-275311), etc.

[0113] [Acrylic polyols] Acrylic polyols can be obtained, for example, by polymerizing a polymerizable monomer having one or more active hydrogen atoms in one molecule, or by copolymerizing a polymerizable monomer having one or more active hydrogen atoms in one molecule with, as needed, another monomer copolymerizable with the polymerizable monomer.

[0114] Examples of polymerizable monomers having one or more active hydrogen atoms in one molecule include the following (i) to (iii), which may be used singly or in combination of two or more. (i) Acrylic acid esters having active hydrogen, such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate. (ii) Methacrylates having active hydrogen, such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 2-hydroxybutyl methacrylate. (iii) (meth)acrylic acid esters having polyvalent active hydrogen, such as acrylic acid monoester or methacrylic acid monoester of glycerin, and acrylic acid monoester or methacrylic acid monoester of trimethylolpropane.

[0115] Examples of other monomers copolymerizable with the polymerizable monomer include the following (i) to (v), which may be used singly or in combination of two or more. (i) Acrylic acid esters such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. (ii) Methacrylates such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, and glycidyl methacrylate. (iii) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid. (iv) Unsaturated amides such as acrylamide, N-methylolacrylamide, and diacetoneacrylamide. (v) Styrene, vinyl toluene, vinyl acetate, acrylonitrile, etc.

[0116] Other examples include acrylic polyols obtained by copolymerizing polymerizable ultraviolet-stable monomers disclosed in Reference 3 (JP-A No. 1-261409) and Reference 4 (JP-A No. 3-006273).

[0117] Specific examples of the polymerizable ultraviolet-stable monomer include 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, and 2-hydroxy-4-(3-methacryloxy-2-hydroxypropoxy)benzophenone.

[0118] For example, the above-mentioned monomer components are solution polymerized in the presence of a known radical polymerization initiator such as a peroxide or an azo compound, and the resulting solution is diluted with an organic solvent or the like as necessary to obtain an acrylic polyol.

[0119] An aqueous acrylic polyol solution can be obtained by a known method such as solution polymerization of an olefinically unsaturated compound followed by conversion into an aqueous layer, emulsion polymerization, etc. In this case, water solubility or water dispersibility can be imparted by neutralizing the acidic moiety of a carboxylic acid-containing monomer such as acrylic acid or methacrylic acid, or a sulfonic acid-containing monomer, with an amine or ammonia.

[0120] [NCO / OH] The molar equivalent ratio (NCO / OH) of the isocyanate groups of the blocked polyisocyanate to the hydroxyl groups of the polyol contained in the thermosetting composition of this embodiment is determined depending on the required physical properties of the resin film, but is preferably 0.01 to 2.0, more preferably 0.02 to 1.5, and even more preferably 0.04 to 1.2. By keeping the ratio within the above range, a thermosetting composition having excellent storage stability and curability when formed into a resin film can be obtained. The isocyanate groups of the blocked polyisocyanate component refer to both the isocyanate groups that have reacted with a blocking agent and the isocyanate groups that have not reacted.

[0121] [Hydroxyl value] The hydroxyl value of the polyol is preferably 30 mgKOH / g or more and 250 mgKOH / g or less, more preferably 40 mgKOH / g or more and 200 mgKOH / g or less, and even more preferably 45 mgKOH / g or more and 180 mgKOH / g or less. When the hydroxyl value of the polyhydric hydroxy compound is within the above range, a resin film having excellent physical properties such as tensile strength can be obtained. The hydroxyl value of the polyhydric hydroxy compound can be measured, for example, in accordance with JIS K1557.

[0122] The content of the blocked polyisocyanate in the thermosetting composition of this embodiment is preferably 5 to 200 parts by mass, more preferably 6 to 180 parts by mass, and even more preferably 10 to 150 parts by mass, relative to 100 parts by mass of the polyol. When the content of the blocked polyisocyanate is within the above range, a resin film having excellent physical properties such as tensile strength can be obtained. The content of the blocked polyisocyanate can be calculated, for example, from the blending amount, or can be calculated by identifying and quantifying the blocked polyisocyanate using nuclear magnetic resonance (NMR) and gas chromatography / mass spectrometry (GC / MS).

[0123] Deionized water In one embodiment of the present invention, the thermosetting composition is an aqueous thermosetting composition containing deionized water. When the thermosetting composition is an aqueous thermosetting composition, the content of deionized water is preferably 20% by mass or more and 90% by mass or less, and more preferably 30% by mass or more and 80% by mass or less, based on the total amount of the aqueous thermosetting composition.

[0124] <Basic composition> When the thermosetting composition is an aqueous thermosetting composition, if the polyol contained in the aqueous thermosetting composition is a carboxyl group-containing polyol, the carboxyl group is preferably neutralized with a basic composition. The basic composition is not particularly limited as long as it has an acid dissociation constant (pKa) of 7.0 or more. If the pKa is 7.0 or more, it can be used as a neutralizer for the carboxyl group of polyols, etc. The acid dissociation constant (pKa) can be measured at 20°C by potentiometric titration.

[0125] The amount of the basic composition added in the present invention is such that the basic groups are 30 mol% or more when the amount of carboxyl groups in the polyol is 100 mol%. The lower limit is preferably 50 mol%, more preferably 70 mol%, and even more preferably 100 mol% or more. The upper limit is preferably 500 mol%, more preferably 400 mol%, and even more preferably 300 mol%. In the present invention, it is considered significant that the basic composition is present in excess of the amount that forms a neutralized salt of the carboxyl groups in the polyol. In this case, the carboxyl groups in the polyol are based on the acid components charged during polyol production.

[0126] The basic composition comprises a weakly basic compound having an acid dissociation constant (pKa) of 7.0 to 8.5 and a basic compound having a pKa of more than 8.5, and the ratio of the weakly basic compound to the total basic composition is preferably 20 mol % or more.

[0127] The lower limit of the composition ratio of the weakly basic compound in the entire basic composition is preferably 30 mol%, more preferably 40 mol%, and even more preferably 50 mol%. In the present invention, adding the weakly basic compound in an amount of 20 mol% or more in the entire basic composition is preferable because the pH of the adjusted thermosetting composition does not become too high.

[0128] The upper limit of the pKa of the weakly basic compound is preferably 8.3 or less, and more preferably 8.0 or less. Specific examples of the weakly basic compound (C1) having a pKa of 7.0 to 8.5 include morpholine derivatives such as morpholine (pKa: 8.4), N-allylmorpholine (pKa: 7.1), N-methylmorpholine (pKa: 7.4), and N-ethylmorpholine (pKa: 7.7); tertiary amines such as triallylamine (pKa: 8.3) and triethanolamine (pKa: 7.8); 2-methylimidazole (pKa: 7.8); and phthalamide (pKa: 8.3). Among these, N-allylmorpholine, N-methylmorpholine, N-ethylmorpholine, triethanolamine, and 2-methylimidazole are more preferred, and N-methylmorpholine and N-ethylmorpholine are even more preferred.

[0129] Specific examples of basic compounds with a pKa of more than 8.5 include trimethylamine (pKa: 9.8), triethylamine (pKa: 11.0), and dimethylethanolamine (pKa: 9.4).

[0130] When the thermosetting composition is an aqueous thermosetting composition, the pH of the aqueous thermosetting composition measured at room temperature (25°C) during blending is preferably 7.0 or higher, more preferably 7.5 or higher, and even more preferably 7.8 or higher. The pH of the aqueous thermosetting composition measured at room temperature (25°C) during blending is preferably 9.0 or lower, more preferably 8.6 or lower, even more preferably 8.4 or lower, and particularly preferably 8.2 or lower. The upper and lower limits can be combined in any desired manner. The pH of the aqueous thermosetting composition when measured at room temperature (25°C) during blending is, for example, 7.0 to 9.0, 7.5 to 8.4, or 7.8 to 8.2. It is preferably 7.0 to 9.0. The lower limit is more preferably 7.5, and even more preferably 7.8, and the upper limit is more preferably 8.6, and even more preferably 8.4, and most preferably 8.2. If the pH measured at room temperature (25°C) during blending of the aqueous thermosetting composition is within the above range, the stability of the pigments such as aluminum and additives such as rheology control agents can be maintained.

[0131] The basic composition may be added to the polyol or blocked polyisocyanate component in advance, or may be added after the polyol and blocked polyisocyanate components are mixed and dispersed. The basic composition may also be added after being dissolved in water, a solvent, or the like in advance.

[0132] <Nonionic dispersant> When the thermosetting composition is an aqueous thermosetting composition, it preferably contains at least two or more nonionic dispersants. Here, "two or more" refers to multiple nonionic dispersants with different HLB values. The inclusion of multiple nonionic dispersants with different HLB values ​​can improve the emulsification ability of the blocked polyisocyanate in water and the aqueous dispersion stability. This effect is most pronounced when at least two or more nonionic dispersants are mixed, the difference between the nonionic dispersant with the highest HLB value and the nonionic dispersant with the lowest HLB value is 5 or more, and the weighted average HLB value of all nonionic dispersants contained in the thermosetting composition is 14 to 17.

[0133] The difference between the nonionic dispersant having the maximum HLB value and the nonionic dispersant having the minimum HLB value is preferably 7 or more, more preferably 8 or more, and even more preferably 9 or more. The upper limit is preferably 20 or less, and more preferably 15 or less.

[0134] The HLB (Hydrophile-Lipophile Balance) value of a nonionic dispersant is commonly used to indicate the degree of affinity of the dispersant for oil and water, and can be calculated using the following formula. HLB value = 20 × total formula weight of hydrophilic parts / molecular weight

[0135] The nonionic dispersant used is not particularly limited as long as its HLB value calculated by the above method is within a specific range. Specific examples of nonionic dispersants include polyoxyethylene alkyl ether type compounds, polyoxyalkylene derivative type compounds, polyoxyethylene polycyclic phenyl ether type compounds, sorbitan fatty acid ester type compounds, glycerin fatty acid ester type compounds, polyoxyethylene fatty acid ester type compounds, polyoxyethylene castor oil type compounds, and polyoxyethylene alkylamine type compounds. Among these nonionic dispersants, polyoxyethylene alkyl ether type compounds and polyoxyethylene polycyclic phenyl ether type compounds are preferred.

[0136] The content of the nonionic dispersant is preferably 1% by mass or more and 30% by mass or less, more preferably 1.5% by mass or more and 20% by mass or less, even more preferably 2% by mass or more and 15% by mass or less, and particularly preferably 3% by mass or more and 10% by mass or less, based on the total amount of the blocked polyisocyanate. By ensuring that the content of the nonionic dispersant is equal to or greater than the above-mentioned lower limit, the storage stability of the aqueous thermosetting composition can be improved. Furthermore, by ensuring that the content of the nonionic dispersant is equal to or less than the above-mentioned upper limit, the hardness of the resin film can be improved.

[0137] When a nonionic dispersant satisfying the above conditions is contained in the system, an anionic dispersant may also be used. Specific examples of anionic dispersants include fatty acid salt compounds, alkyl sulfate ester compounds, polyoxyethylene alkyl ether sulfate ester compounds, polyoxyethylene alkyl ether sulfate compounds, polyoxyethylene polycyclic phenyl ether sulfate compounds, polyoxyalkylene alkenyl ether sulfate compounds, alkylbenzene sulfonate compounds, sulfosuccinate compounds, and alkyl phosphate compounds. Examples of polyoxyethylene alkyl ether sulfate compounds include polyoxyethylene alkyl ether ammonium sulfate and polyoxyethylene alkyl ether sodium sulfate. Examples of polyoxyethylene polycyclic phenyl ether sulfate compounds include polyoxyethylene polycyclic phenyl ether ammonium sulfate and polyoxyethylene polycyclic phenyl ether sodium sulfate. Examples of polyoxyalkylene alkenyl ether sulfate compounds include polyoxyalkylene alkenyl ether ammonium sulfate. These anionic dispersants may be used alone or in combination.

[0138] Among these anionic dispersants, polyoxyethylene polycyclic phenyl ether ammonium sulfate, polyoxyethylene polycyclic phenyl ether sodium sulfate, polyoxyethylene alkyl ether ammonium sulfate, and polyoxyethylene alkyl ether sodium sulfate are preferred.

[0139] <Other additives> The thermosetting composition of the present embodiment may further contain other additives. Other additives include curing agents capable of reacting with crosslinkable functional groups in the polyol, curing catalysts, solvents, pigments (extender pigments, colored pigments, metallic pigments, etc.), ultraviolet absorbers, light stabilizers, radical stabilizers, anti-yellowing agents that suppress discoloration during the baking process, coating surface conditioners, flow conditioners, pigment dispersants, antifoaming agents, thickeners, film-forming aids, etc.

[0140] <Method for producing thermosetting composition> When producing a thermosetting composition, first, additives such as a curing agent capable of reacting with a crosslinkable functional group in the polyol, a curing catalyst, a solvent, pigments (extender pigments, colored pigments, metallic pigments, etc.), an ultraviolet absorber, a light stabilizer, a radical stabilizer, an anti-yellowing agent that suppresses coloring during the baking step, a coating surface conditioner, a flow conditioner, a pigment dispersant, an antifoaming agent, a thickener, and a film-forming aid are added to a polyol or an aqueous dispersion thereof, as needed.

[0141] Next, a blocked polyisocyanate component or a water dispersion thereof is added as a curing agent, and then the mixture is forcibly stirred with a stirring device to obtain a thermosetting composition or a water-based thermosetting composition.

[0142] <Resin film> One aspect of the present invention is a resin film that is a cured product of the thermosetting composition or the aqueous thermosetting composition of the present embodiment. The resin film can be obtained by applying the thermosetting composition of the present embodiment or the aqueous thermosetting composition to a substrate using a known method such as roll coating, curtain flow coating, spray coating, bell coating, or electrostatic coating, and then heating to cure the composition.

[0143] <Method of manufacturing resin film> One aspect of the present invention is a method for producing a resin film, comprising the steps of applying the thermosetting composition of the present embodiment and heating the applied thermosetting composition at a temperature of 50°C or higher and 140°C or lower for 5 minutes or longer and 1,440 minutes or shorter, or at a temperature of 105°C or higher and 200°C or lower for 5 seconds or longer and 900 seconds or shorter, to obtain a resin film. By setting the temperature conditions and curing time within the above ranges, a resin film with good hardness can be obtained.

[0144] The substrate is not particularly limited, and examples thereof include outer panels of automobile bodies such as passenger cars, trucks, motorcycles, and buses; automobile parts such as bumpers; outer panels of household electrical appliances such as mobile phones and audio equipment; and various films.

[0145] The material of the substrate is not particularly limited, and examples thereof include metal materials such as iron, aluminum, brass, copper, tinplate, stainless steel, zinc-plated steel, and zinc alloy (Zn-Al, Zn-Ni, Zn-Fe, etc.)-plated steel; resins such as polyethylene resin, polypropylene resin, acrylonitrile-butadiene-styrene (ABS) resin, polyamide resin, acrylic resin, vinylidene chloride resin, polycarbonate resin, polyurethane resin, and epoxy resin; plastic materials such as various FRPs; inorganic materials such as glass, cement, and concrete; and fibrous materials such as wood, paper, and cloth, among which metal materials and plastic materials are preferred.

[0146] The substrate may be the surface of the above-mentioned metal material, or the metal surface of a car body or the like formed from the above-mentioned metal material, which has been subjected to a surface treatment such as phosphate treatment, chromate treatment, or composite oxide treatment, and further, may have a coating film formed thereon. The substrate with a coating film formed thereon may be one that has been subjected to a surface treatment as necessary and then a primer coating film formed thereon, for example, a car body on which a primer coating film has been formed by electro-deposition thermosetting. The substrate may be the surface of the above-mentioned plastic material, or the plastic surface of an automobile part or the like formed from the above-mentioned plastic material, which has been subjected to a desired surface treatment. The substrate may also be a combination of a plastic material and a metal material. [Example]

[0147] The present embodiment will be described in more detail below based on examples and comparative examples, but the present embodiment is not limited to the following examples in any way.

[0148] <Test items> The thermosetting compositions obtained in the examples and comparative examples were subjected to measurement and evaluation of various physical properties according to the methods described below.

[0149] [Physical Properties 1] (Isocyanate group (NCO) content) In order to measure the NCO content of the polyisocyanate, the polyisocyanate before being blocked with a blocking agent was used as a measurement sample. First, 2 g to 3 g of the measurement sample was weighed out into a flask (W g). Next, 20 mL of toluene was added to dissolve the measurement sample. Next, 20 mL of a 2 N toluene solution of di-n-butylamine was added, mixed, and left at room temperature for 15 minutes. Next, 70 mL of isopropyl alcohol was added and mixed. Next, this liquid was titrated with a 1 N hydrochloric acid solution (factor F) as an indicator. The obtained titration value was V2 mL. Next, the titration value obtained without the polyisocyanate sample was V1 mL. Next, the isocyanate group (NCO) content (mass%) of the polyisocyanate was calculated using the following formula: Isocyanate group (NCO) content (mass%) = (V1 - V2) x F x 42 / (W x 1000) x 100

[0150] [Physical Properties 2] (Number average molecular weight and weight average molecular weight) The number average molecular weight and weight average molecular weight are those measured by gel permeation chromatography (GPC) using the following equipment, using polystyrene standards. In order to measure the number average molecular weight of the polyisocyanate, the polyisocyanate before being blocked with a blocking agent was used as a measurement sample. The weight average molecular weight was measured using the thermosetting composition or the polyhydroxy compound as it was. The measurement conditions are as follows:

[0151] (Measurement conditions) Equipment: Tosoh Corporation, HLC-802A Column: Tosoh Corporation, G1000HXL x 1 G2000HXL x 1 G3000HXL x 1 Carrier: Tetrahydrofuran Detection method: differential refractometer

[0152] [Physical Properties 3] (average number of isocyanate groups) The average number of isocyanate groups (average NCO number) of the polyisocyanate was calculated by the following formula. In the formula, "Mn" is the number average molecular weight of the polyisocyanate before blocking with a blocking agent, and the value measured in "Property 2" above was used. "NCO content" is the isocyanate group content of the polyisocyanate measured before blocking with a blocking agent, and the value calculated in "Property 1" above was used. Average number of isocyanate groups = (Mn × NCO content × 0.01) / 42

[0153] [Physical Properties 4] (Solid content of thermosetting composition) The solid content of the thermosetting composition was determined as follows. First, an aluminum dish with a bottom diameter of 38 mm was precisely weighed. Then, approximately 1 g of the thermosetting composition produced in the Examples and Comparative Examples was placed on the aluminum dish and precisely weighed (W1). The thermosetting composition was then adjusted to a uniform thickness. The thermosetting composition placed on the aluminum dish was then kept in an oven at 75°C for 2.5 hours. After the aluminum dish returned to room temperature, the thermosetting composition remaining on the aluminum dish was precisely weighed (W2). The solid content (% by mass) of the thermosetting composition was then calculated using the following formula: Solid content of thermosetting composition (mass%) = W2 / W1 × 100

[0154] [Physical Properties 5] (Content (mol) of structural unit (I)) The content of the structural unit (I) in the thermosetting composition is 13 Calculated by C-NMR. Device: JEOL “JEOL-ECZ500(SC)” (product name) Solvent: deuterated chloroform Accumulation count: 5120 times Sample concentration: 50 wt / vol% Chemical shift standard: deuterated chloroform was used as 77.0 ppm.

[0155] [Physical Properties 6] (Molar ratio of structural unit (I-1) in structural unit (I)) The molar ratio of the structural unit (I-1) to the structural unit (I) in the thermosetting composition (structural unit (I-1) / structural unit (I)) was calculated using the method shown below. Specifically, we used the JEOL-ECZ500 (SC) (product name) manufactured by JEOL. 13 The total molar amount of the structural unit (I) (including the structural unit (I-1)) and the molar amount of the structural unit (I-1) were calculated by C-NMR measurement, and the molar ratio was determined.

[0156] (Measurement conditions) Device: JEOL “JEOL-ECZ500(SC)” (product name) Solvent: deuterated chloroform Accumulation count: 5120 times Sample concentration: 50 wt / vol% Chemical shift standard: deuterated chloroform was used as 77.0 ppm.

[0157] [Physical Properties 7] (molar ratio of structural unit (II) / structural unit (I)) The molar ratio of the structural unit (II) to the structural unit (I) (structural unit (II) / structural unit (I)) is determined by evaporating the thermosetting composition at 50°C or less to remove the solvent and other components, drying under reduced pressure, and then 13 The molar ratio of the structural unit (II) to the structural unit (I) was calculated by measuring the composition ratio of the structural unit (II) to the structural unit (I) by C-NMR.

[0158] (Measurement conditions) Device: JEOL “JEOL-ECZ500(SC)” (product name) Solvent: deuterated chloroform Accumulation count: 5120 times Sample concentration: 50 wt / vol% Chemical shift standard: deuterated chloroform was used as 77.0 ppm.

[0159] [Rating 1] (Storage stability) The storage stability was evaluated by measuring the viscosity of the thermosetting composition before and after storage under predetermined conditions, and by the change in viscosity immediately after blending. The viscosity of the obtained thermosetting composition at 25°C immediately after blending (viscosity before storage) and the viscosity at 25°C after storing in a 20 mL glass bottle at 23°C for 7 hours (viscosity after storage) were measured using an E-type viscometer (manufactured by Tokimec Inc.), and the viscosity increase rate was calculated using the formula (viscosity after storage / viscosity before storage - 1) × 100. The viscosity increase rate was evaluated according to the following criteria. A: Less than 30% B: 30% or more but less than 40% C: 40% or more

[0160] [Rating 3] (Low temperature curing: gel fraction) The obtained thermosetting compositions were coated onto polypropylene (PP) plates to a dry film thickness of 40 μm, both immediately after blending (before storage) and after blending and storage at 23°C for 7 hours (after storage), and then dried by heating at 80°C for 30 minutes to obtain resin films. The gel fraction of the resulting resin films was measured. The gel fraction was determined as a percentage (mass%) by dividing the mass of the undissolved portion of the resin film when immersed in acetone at 23°C for 24 hours by the mass before immersion. Low-temperature curability was evaluated from the obtained gel fraction according to the following evaluation criteria. A: 85% by mass or more B: 80% by mass or more and less than 85% by mass C: Less than 80% by mass

[0161] [Synthesis Example 1] (Synthesis of Polyisocyanate P-1) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by mass of HDI and 5.2 parts by mass of a polyester polyol derived from a trihydric alcohol and ε-caprolactone (Daicel Chemical Industries, Ltd., "PLACCEL 303" (trade name), average functionality: 3, number-average molecular weight: 300) under a nitrogen stream. The temperature inside the reactor was maintained at 88°C for 1 hour with stirring to carry out a urethane reaction. The temperature inside the reactor was then maintained at 62°C, and an isocyanuration catalyst, tetramethylammonium caprylate, was added. When the yield reached 51% by mass, phosphoric acid was added to terminate the reaction. The reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator to obtain an isocyanurate-type polyisocyanate (hereinafter sometimes referred to as "polyisocyanate P-1"). The NCO content of the obtained polyisocyanate P-1 was 18.8% by mass, the number average molecular weight was 1180, and the average number of isocyanate groups was 5.3. 1 H-NMR analysis confirmed the presence of isocyanurate groups.

[0162] [Synthesis Example 2] (Synthesis of polyisocyanate P-2 modified with a compound having an EO unit) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by weight of polyisocyanate P-1, 14 parts by weight of dipropylene glycol dimethyl ether (DPDM), 12 parts by weight of methoxypolyethylene glycol (MPG-081, number of repeating oxyethylene groups (EO): 15, manufactured by Nippon Nyukazai Co., Ltd.) (4 mol % relative to 100 mol % of the isocyanate groups in polyisocyanate P-1), and 0.08 parts by weight of 2-ethylhexyl acid phosphate (JP-508T, manufactured by Johoku Chemical Industry Co., Ltd.) under a nitrogen stream. The resulting mixture was stirred at 120°C for 2 hours to produce hydrophilic compound-modified polyisocyanate P-2. The NCO content of the resulting polyisocyanate P-2 was 14% by weight, and the average number of isocyanate groups was 5.1.

[0163] [Synthesis Example 3] (Synthesis of polyisocyanate P-3 modified with a compound having an EO unit) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by weight of polyisocyanate P-1, 16 parts by weight of dipropylene glycol dimethyl ether (DPDM), 3 parts by weight of methoxypolyethylene glycol (MPG-081, number of repeating oxyethylene groups (EO): 15, manufactured by Nippon Nyukazai Co., Ltd.) (amount equivalent to 1 mol % relative to 100 mol % of the isocyanate groups in polyisocyanate P-1), and 0.08 parts by weight of 2-ethylhexyl acid phosphate (JP-508T, manufactured by Johoku Chemical Industry Co., Ltd.) under a nitrogen stream. The mixture was stirred at 120°C for 2 hours to obtain hydrophilic compound-modified polyisocyanate P-3. The resulting polyisocyanate P-3 had an NCO content of 15.3% by weight and an average number of isocyanate groups of 5.2.

[0164] [Synthesis Example 4] (Synthesis of polyisocyanate P-4 modified with a compound having an EO unit) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by weight of polyisocyanate P-1, 18 parts by weight of dipropylene glycol dimethyl ether (DPDM), 45 parts by weight of methoxypolyethylene glycol (MPG-081, number of repeating oxyethylene groups (EO): 15, manufactured by Nippon Nyukazai Co., Ltd.) (amount equivalent to 15 mol % relative to 100 mol % of the isocyanate groups in polyisocyanate P-1), and 0.08 parts by weight of 2-ethylhexyl acid phosphate (JP-508T, manufactured by Johoku Chemical Industry Co., Ltd.) under a nitrogen stream. The mixture was stirred at 120°C for 2 hours to produce hydrophilic compound-modified polyisocyanate P-4. The resulting polyisocyanate P-4 had an NCO content of 9.6% by weight and an average number of isocyanate groups of 4.5.

[0165] [Synthesis Example 5] (Synthesis of Polyisocyanate P-5) 100 parts by mass of polyisocyanate P-1, 11 parts by mass of dipropylene glycol dimethyl ether (DPDM), and 0.08 parts by mass of 2-ethylhexyl acid phosphate (JP-508T, manufactured by Johoku Chemical Industry Co., Ltd.) were mixed in a four-neck flask equipped with a thermometer, stirring blade, and reflux condenser under a nitrogen stream and stirred at 120°C for 2 hours to obtain hydrophilic compound-unmodified polyisocyanate P-5. The NCO content of the obtained polyisocyanate P-5 was 16.6% by mass, and the average number of isocyanate groups was 5.3.

[0166] [Synthesis Example 6] (Synthesis of polyisocyanate P-6 modified with a compound containing EO units) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by weight of polyisocyanate P-1, 18 parts by weight of dipropylene glycol dimethyl ether (DPDM), 60 parts by weight of methoxypolyethylene glycol (MPG-081, number of repeating oxyethylene groups (EO): 15, manufactured by Nippon Nyukazai Co., Ltd.) (20 mol % relative to 100 mol % of the isocyanate groups in polyisocyanate P-1), and 0.08 parts by weight of 2-ethylhexyl acid phosphate (JP-508T, manufactured by Johoku Chemical Industry Co., Ltd.) under a nitrogen stream. The resulting mixture was stirred at 120°C for 2 hours to produce hydrophilic compound-modified polyisocyanate P-6. The NCO content of the resulting polyisocyanate P-6 was 8.3% by weight, and the average number of isocyanate groups was 4.2.

[0167] [Synthesis Example 7] (Synthesis of polyisocyanate P-7 modified with a compound containing PO units) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by weight of polyisocyanate P-1, 18 parts by weight of dipropylene glycol dimethyl ether (DPDM), 60 parts by weight of polypropylene glycol (EXCENOL 1020, calculated number of oxypropylene (PO) repeating units: 17, manufactured by Nippon Nyukazai Co., Ltd.) (4 mol % relative to 100 mol % of isocyanate groups in polyisocyanate P-2), and 0.08 parts by weight of 2-ethylhexyl acid phosphate (JP-508T, manufactured by Johoku Chemical Industry Co., Ltd.) under a nitrogen stream. The mixture was stirred at 120°C for 2 hours to obtain hydrophilic compound-modified polyisocyanate P-7. The resulting polyisocyanate P-7 had an NCO content of 14.6% by weight and an average number of isocyanate groups of 5.1.

[0168] [Synthesis Example 8] (Synthesis of polyisocyanate P-8 modified with a compound containing BO units) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was mixed under nitrogen flow with 100 parts by weight of polyisocyanate P-1, 14 parts by weight of dipropylene glycol dimethyl ether (DPDM), 17.9 parts by weight of polytetramethylene ether glycol (PTMG2000, calculated number of oxybutylene (BO) repeating units: 28, manufactured by Mitsubishi Chemical Corporation) (4 mol % relative to 100 mol % of isocyanate groups in polyisocyanate P-2), and 0.08 parts by weight of 2-ethylhexyl acid phosphate (JP-508T, manufactured by Johoku Chemical Industry Co., Ltd.). The mixture was stirred at 120°C for 2 hours to obtain hydrophilic compound-modified polyisocyanate P-8. The NCO content of the resulting polyisocyanate P-8 was 13.4 % by weight, and the average number of isocyanate groups was 5.1.

[0169] [Synthesis Example 9] (Synthesis of Blocked Polyisocyanate BL-1) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by mass of the polyisocyanate P-2 obtained in Synthesis Example 2 and 64 parts by mass of diisopropyl malonate (102 mol% relative to 100 mol% NCO groups) under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to adjust the solids content to 60% by mass. Next, 1.0 part by mass of a methanol solution containing sodium methylate (28% by mass relative to the total mass of the solution) was added dropwise with stirring. The external bath was then adjusted so that the solution temperature was 55°C, and the blocking reaction was carried out at 55°C for 5 hours to obtain a thermosetting composition intermediate with a solids content of 60% by mass. Subsequently, 73.4 parts by mass of 2-methyl-2-butanol (250 mol% relative to the blocked isocyanate groups) was added, and the reaction was carried out at 120°C for 3 hours while the generated isopropyl alcohol was removed by distillation under normal pressure. Thereafter, the isopropanol and 2-methyl-2-butanol were further distilled off at 60°C under reduced pressure (50 kPa), and finally, dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60% by mass, thereby obtaining blocked polyisocyanate component BL-1.

[0170] [Synthesis Example 10] (Synthesis of Blocked Polyisocyanate BL-2) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by weight of the polyisocyanate P-2 obtained in Synthesis Example 2 and 64 parts by weight of diisopropyl malonate (102 mol% relative to 100 mol% NCO groups) under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to adjust the solids content to 60% by weight. Next, 1.0 part by weight of a methanol solution containing sodium methylate (28% by weight relative to the total weight of the solution) was added dropwise with stirring. The external bath was then adjusted to a solution temperature of 55°C. Blocking reaction was carried out at 55°C for 5 hours to obtain a thermosetting composition intermediate with a solids content of 60% by weight. Subsequently, 73.4 parts by weight of 2-methyl-2-butanol (250 mol% relative to blocked isocyanate groups) was added, and the reaction was carried out at 105°C for 3 hours. Thereafter, isopropanol and 2-methyl-2-butanol were further distilled off at 60°C under reduced pressure (50 kPa), and finally, dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60 mass % to obtain blocked polyisocyanate component BL-2.

[0171] [Synthesis Example 11] (Synthesis of Blocked Polyisocyanate BL-3) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by weight of the polyisocyanate P-3 obtained in Synthesis Example 3 and 70 parts by weight of diisopropyl malonate (102 mol% relative to 100 mol% NCO groups) under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to adjust the solids content to 60% by weight. Next, 1.0 part by weight of a methanol solution containing sodium methylate (28% by weight relative to the total weight of the solution) was added dropwise with stirring, and the external bath was adjusted to a solution temperature of 55°C. A blocking reaction was carried out at 55°C for 5 hours to obtain a thermosetting composition intermediate with a solids content of 60% by weight. Subsequently, 80.2 parts by weight of 2-methyl-2-butanol (250 mol% relative to blocked isocyanate groups) was added, and the reaction was carried out at 120°C for 3 hours while the generated isopropyl alcohol was removed by distillation under atmospheric pressure. Thereafter, isopropanol and 2-methyl-2-butanol were further distilled off at 60°C under reduced pressure (50 kPa), and finally, dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60 mass % to obtain blocked polyisocyanate component BL-3.

[0172] [Synthesis Example 12] (Synthesis of Blocked Polyisocyanate BL-4) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by weight of the polyisocyanate P-4 obtained in Synthesis Example 4 and 43.8 parts by weight of diisopropyl malonate (102 mol% relative to 100 mol% NCO groups) under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to adjust the solids content to 60% by weight. Next, with stirring, 1.0 part by weight of a methanol solution containing sodium methylate (28% by weight relative to the total weight of the solution) was added dropwise. The external bath was then adjusted to a solution temperature of 55°C. A blocking reaction was carried out at 55°C for 5 hours to obtain a thermosetting composition intermediate with a solids content of 60% by weight. Subsequently, 50.3 parts by weight of 2-methyl-2-butanol (250 mol% relative to blocked isocyanate groups) was added, and the reaction was carried out at 120°C for 3 hours, while the generated isopropyl alcohol was removed by distillation under atmospheric pressure. Thereafter, isopropanol and 2-methyl-2-butanol were further distilled off at 60°C under reduced pressure (50 kPa), and finally, dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60 mass % to obtain blocked polyisocyanate component BL-4.

[0173] [Synthesis Example 13] (Synthesis of Blocked Polyisocyanate BL-5) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by weight of the polyisocyanate P-2 obtained in Synthesis Example 2 and 54.5 parts by weight of diethyl malonate (102 mol% relative to 100 mol% NCO groups) under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to adjust the solids content to 60% by weight. Next, 1.0 part by weight of a methanol solution containing sodium methylate (28% by weight relative to the total weight of the solution) was added dropwise with stirring, and the external bath was adjusted to a solution temperature of 55°C. A blocking reaction was carried out at 55°C for 5 hours to obtain a thermosetting composition intermediate with a solids content of 60% by weight. Subsequently, 73.4 parts by weight of 2-methyl-2-butanol (250 mol% relative to blocked isocyanate groups) was added, and the reaction was carried out at 120°C for 3 hours while the generated isopropyl alcohol was removed by distillation under atmospheric pressure. Thereafter, isopropanol and 2-methyl-2-butanol were further distilled off at 60°C under reduced pressure (50 kPa), and finally, dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60 mass % to obtain blocked polyisocyanate component BL-5.

[0174] [Synthesis Example 14] (Synthesis of Blocked Polyisocyanate BL-6) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by weight of the polyisocyanate P-5 obtained in Synthesis Example 5 and 75.7 parts by weight of diisopropyl malonate (102 mol% relative to 100 mol% NCO groups) under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to adjust the solids content to 60% by weight. Next, with stirring, 1.0 part by weight of a methanol solution containing sodium methylate (28% by weight relative to the total weight of the solution) was added dropwise, and the external bath was adjusted to a solution temperature of 55°C. A blocking reaction was carried out at 55°C for 5 hours to obtain a thermosetting composition intermediate with a solids content of 60% by weight. Subsequently, 86.8 parts by weight of 2-methyl-2-butanol (250 mol% relative to blocked isocyanate groups) was added, and the reaction was carried out at 120°C for 3 hours while the generated isopropyl alcohol was removed by distillation under atmospheric pressure. Thereafter, isopropanol and 2-methyl-2-butanol were further distilled off at 60°C under reduced pressure (50 kPa), and finally, dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60 mass % to obtain blocked polyisocyanate component BL-6.

[0175] [Synthesis Example 15] (Synthesis of Blocked Polyisocyanate BL-7) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by weight of the polyisocyanate P-2 obtained in Synthesis Example 2 and 64 parts by weight of diisopropyl malonate (102 mol% relative to 100 mol% NCO groups) under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to adjust the solids content to 60% by weight. Next, 1.0 part by weight of a methanol solution containing sodium methylate (28% by weight relative to the total weight of the solution) was added dropwise with stirring, and the external bath was adjusted to a solution temperature of 55°C. A blocking reaction was carried out at 55°C for 5 hours to obtain a thermosetting composition intermediate with a solids content of 60% by weight. Then, 1 part by weight of 2-methyl-2-butanol (3.4 mol% relative to blocked isocyanate groups) was added, and the reaction was carried out at 120°C for 3 hours while the generated isopropyl alcohol was removed by distillation under atmospheric pressure. Thereafter, isopropanol and 2-methyl-2-butanol were further distilled off at 60°C under reduced pressure (50 kPa), and finally, dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60 mass % to obtain blocked polyisocyanate component BL-7.

[0176] [Synthesis Example 16] (Synthesis of Blocked Polyisocyanate BL-8) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by weight of the polyisocyanate P-2 obtained in Synthesis Example 2 and 37.8 parts by weight of diisopropyl malonate (102 mol% relative to 100 mol% NCO groups) under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to adjust the solids content to 60% by weight. Next, 1.0 part by weight of a methanol solution containing sodium methylate (28% by weight relative to the total weight of the solution) was added dropwise with stirring, and the external bath was adjusted to a solution temperature of 55°C. A blocking reaction was carried out at 55°C for 5 hours to obtain a thermosetting composition intermediate with a solids content of 60% by weight. Then, 43.3 parts by weight of 2-methyl-2-butanol (250 mol% relative to blocked isocyanate groups) was added, and the reaction was carried out at 120°C for 3 hours while the generated isopropyl alcohol was removed by distillation under atmospheric pressure. Thereafter, isopropanol and 2-methyl-2-butanol were further distilled off at 60°C under reduced pressure (50 kPa), and finally, dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60 mass % to obtain blocked polyisocyanate component BL-8.

[0177] [Synthesis Example 17] (Synthesis of Blocked Polyisocyanate BL-9) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by mass of the polyisocyanate P-7 obtained in Synthesis Example 2 and 66.7 parts by mass of diisopropyl malonate (102 mol% relative to 100 mol% NCO groups) under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to adjust the solids content to 60% by mass. Next, 1.0 part by mass of a methanol solution containing sodium methylate (28% by mass relative to the total mass of the solution) was added dropwise with stirring. The external bath was then adjusted so that the solution temperature was 55°C, and the blocking reaction was carried out at 55°C for 5 hours to obtain a thermosetting composition intermediate with a solids content of 60% by mass. Subsequently, 76.5 parts by mass of 2-methyl-2-butanol (250 mol % relative to the blocked isocyanate groups) was added, and the mixture was reacted at 120°C for 3 hours while the generated isopropyl alcohol was removed by distillation under normal pressure. Thereafter, the isopropanol and 2-methyl-2-butanol were further distilled off at 60°C under reduced pressure (50 kPa), and finally, dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60% by mass, thereby obtaining blocked polyisocyanate component BL-9.

[0178] [Synthesis Example 18] (Synthesis of Blocked Polyisocyanate BL-10) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by mass of the polyisocyanate P-8 obtained in Synthesis Example 2 and 61.1 parts by mass of diisopropyl malonate (102 mol% relative to 100 mol% NCO groups) under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to adjust the solids content to 60% by mass. Next, 1.0 part by mass of a methanol solution containing sodium methylate (28% by mass relative to the total mass of the solution) was added dropwise with stirring. The external bath was then adjusted so that the solution temperature was 55°C, and the blocking reaction was carried out at 55°C for 5 hours to obtain a thermosetting composition intermediate with a solids content of 60% by mass. Subsequently, 75.1 parts by mass of 2-methyl-2-butanol (250 mol% relative to the blocked isocyanate groups) was added, and the mixture was reacted at 120°C for 3 hours while the generated isopropyl alcohol was removed by distillation under normal pressure. Thereafter, the isopropanol and 2-methyl-2-butanol were further distilled off at 60°C under reduced pressure (50 kPa), and finally, dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60% by mass, thereby obtaining blocked polyisocyanate component BL-10.

[0179] [Synthesis Example 19] (Synthesis of Blocked Polyisocyanate BL-11) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts by weight of the polyisocyanate P-6 obtained in Synthesis Example 6 and 37.8 parts by weight of diisopropyl malonate (102 mol % relative to 100 mol % NCO groups) under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to adjust the final solids content to 60% by weight. Next, 1.0 part by weight of a methanol solution containing sodium methylate (28% by weight relative to the total weight of the solution) was added dropwise with stirring, and the external bath was adjusted to a solution temperature of 55°C. A blocking reaction was carried out at 55°C for 5 hours to obtain a thermosetting composition intermediate with a solids content of 60% by weight. Subsequently, 1.1 parts by weight of 2-methyl-2-butanol (6.3 mol % relative to blocked isocyanate groups) was added and the reaction was carried out at 80°C for 3 hours to obtain blocked polyisocyanate component BL-11.

[0180] [Synthesis Example 20] (Synthesis of Blocked Polyisocyanate BL-12) To a four-neck flask equipped with a thermometer, a stirring blade, and a reflux condenser, 80 parts by mass of the blocked polyisocyanate component BL-1 obtained in Synthesis Example 9 and 20 parts by mass of the blocked polyisocyanate component BL-11 obtained in Synthesis Example 19 were added under a nitrogen stream, and the mixture was stirred at 60°C for 1 hour to adjust the solids content to 60% by mass, yielding blocked polyisocyanate component BL-12.

[0181] The specific structures and compositions of the blocked polyisocyanate components BL-1 to BL-10 and BL-12 produced in Synthesis Examples 9 to 18 and 20 are shown in Table 1. In Table 1, R 11 , R 12 , R 13 , R 14 , R 15 and R 16 represents R in the above general formula (I). 11 , R 12 , R 13 , R 14 , R 15 and R 16 is equivalent to In Table 1, R 21 , R 22 , R 23 and R 24 represents R in the above general formula (II). 21 , R 22 , R 23 and R 24 is equivalent to

[0182] [Table 1]

[0183] <Production of Thermosetting Composition> [Example 1] 5 g of the blocked polyisocyanate component BL-1 obtained in Synthesis Example 1 was weighed out and placed in a container. Next, an acrylic polyol (setalux1152, manufactured by Allnex Corporation, hydroxyl value per resin: 138 mg KOH / g, resin content 51%) (hereinafter sometimes referred to as "polyol 1") was added in such a proportion that the ratio of the molar amount of isocyanate groups to the molar amount of hydroxyl groups in the polyol (NCO / OH) was 1.0.

[0184] Furthermore, n-butanol was added in an amount 1.4 times the moles of NCO in the added BL-1. Finally, butyl acetate was added in a proportion such that the solid content of the thermosetting composition was 45% by mass, and the mixture was stirred at 300 rpm using a propeller blade for 10 minutes to obtain thermosetting composition NK-1. The prepared thermosetting composition was evaluated using the methods described above. The results are shown in Table 2.

[0185] [Examples 2 to 20, 24 to 34, Comparative Examples 1 and 2] The thermosetting compositions of Examples 2 to 20, 24 to 34, and Comparative Examples 1 and 2 (NK-2 to 20, NK-24 to 34, and nk-1 and 2) were obtained using the same method as in Example 1, except that the blocked isocyanate species, alcohol species, and ratios relative to the number of moles of NCO in the blocked isocyanate were set as shown in Table 2. Each of the prepared thermosetting compositions was evaluated using the methods described above. The results are shown in Tables 2 to 8.

[0186] [Example 21] 5 g of the blocked polyisocyanate component BL-1 obtained in Synthesis Example 1 was weighed out and placed in a container. Next, an acrylic polyol (setalux1767, manufactured by Allnex, hydroxyl value per resin: 150 mg KOH / g, resin content 65%) (hereinafter sometimes referred to as "polyol 2") was added in such a proportion that the ratio of the molar amount of isocyanate groups to the molar amount of hydroxyl groups in the polyol (NCO / OH) was 1.0.

[0187] Furthermore, n-butanol was added in an amount 1.4 times the moles of NCO in the added BL-1. Finally, butyl acetate was added in a proportion such that the solid content of the thermosetting composition was 45 mass%. The mixture was stirred at 300 rpm for 10 minutes using a propeller blade to obtain a thermosetting composition (NK-21). The prepared thermosetting composition was evaluated using the methods described above. The results are shown in Table 5.

[0188] [Example 22] A thermosetting composition (NK-22) of Example 22 was obtained using the same method as in Example 21, except that the alcohol was changed from n-butanol to 2-methyl-2-butanol. Each of the prepared thermosetting compositions was evaluated using the methods described above. The results are shown in Table 5.

[0189] [Example 23] 16 g of the blocked polyisocyanate component BL-1 obtained in Synthesis Example 1 was weighed into a container. Next, a nonionic dispersant D1: Newcol 714 (manufactured by Nippon Nyukazai Co., Ltd., polyoxyethylene polycyclic phenyl ether, HLB value calculated by the Griffin equation: 15.0) was added to the blocked polyisocyanate in an amount by weight such that the total amount was 6% by weight of the resin content of the blocked polyisocyanate.

[0190] Next, deionized water was added so that the solid content of the thermosetting composition would be 40% by mass, and the mixture was stirred at 800 rpm for 10 minutes using a propeller blade. Next, an acrylic polyol water dispersion (hydroxyl value per resin: 130 mgKOH / g, manufactured in-house) (hereinafter sometimes referred to as "Polyol 3") was added so that the ratio of the molar amount of isocyanate groups to the molar amount of hydroxyl groups in the polyol (NCO / OH) would be 0.5.

[0191] Next, deionized water was added to the thermosetting composition so that the solids content was 30% by mass, and the mixture was stirred at 700 rpm for 10 minutes using a propeller blade. Finally, triethylamine was added to adjust the pH of the thermosetting composition to 8.2, and the mixture was stirred at 700 rpm for 10 minutes to obtain a thermosetting composition (NK-23). ​​The prepared thermosetting composition was evaluated using the methods described above. The results are shown in Table 5.

[0192] [Example 35] 16 g of the blocked polyisocyanate component BL-12 obtained in Synthesis Example 20 was weighed into a container. Next, nonionic dispersant D1: Newcol 714 (manufactured by Nippon Nyukazai Co., Ltd., polyoxyethylene polycyclic phenyl ether, HLB value calculated by the Griffin equation: 15.0) was added to the blocked polyisocyanate in a weight amount that would result in a total of 6% by weight of the resin content of the blocked polyisocyanate. Furthermore, 2-methyl-2-butanol was added in an amount 1.4 times the number of moles of NCO in BL-12.

[0193] Next, deionized water was added so that the solid content of the thermosetting composition would be 40% by mass, and the mixture was stirred at 800 rpm for 10 minutes using a propeller blade. Next, an acrylic polyol water dispersion (hydroxyl value per resin: 130 mgKOH / g, manufactured in-house) (hereinafter sometimes referred to as "Polyol 3") was added so that the ratio of the molar amount of isocyanate groups to the molar amount of hydroxyl groups in the polyol (NCO / OH) would be 0.5.

[0194] Next, deionized water was added to the thermosetting composition so that the solids content was 30% by mass, and the mixture was stirred at 700 rpm for 10 minutes using a propeller blade. Finally, triethylamine was added to adjust the pH of the thermosetting composition to 8.2, and the mixture was stirred at 700 rpm for 10 minutes to obtain a thermosetting composition (NK-35). The prepared thermosetting composition was evaluated using the methods described above. The results are shown in Table 7.

[0195] [Table 2]

[0196] [Table 3]

[0197] [Table 4]

[0198] [Table 5]

[0199] [Table 6]

[0200] [Table 7]

[0201] [Table 8]

[0202] As shown in Tables 2 to 7 above, the thermosetting compositions NK-1 to 35 (Examples 1 to 35) containing monohydric or dihydric alcohol compounds were evaluated as A or B for storage stability and low-temperature curing property, confirming that they had good storage stability and low-temperature curing property when formed into a resin film. On the other hand, as shown in Table 8 above, the thermosetting compositions nk-1 and nk-2 (Comparative Examples 1 and 2), which did not contain a monohydric or dihydric alcohol compound, were evaluated as C in terms of storage stability and low-temperature curing properties after storage, which were poor.

[0203] As shown in Tables 2 and 5 above, in a comparison between thermosetting compositions NK-1 to 3 (Examples 1 to 3), in which the molar ratio of the alcohol compound to the blocked isocyanate groups contained in the thermosetting composition was 0.2 or more, and thermosetting composition NK-24 (Example 24), in which the molar ratio of the alcohol compound to the blocked isocyanate groups contained in the thermosetting composition was less than 0.2, thermosetting compositions NK-1 to NK-3 tended to have better storage stability.

[0204] As shown in Tables 2, 3, and 6 above, in a comparison between thermosetting compositions NK-5 to 7 (Examples 5 to 7), in which the molar ratio of the alcohol compound to the blocked isocyanate groups contained in the thermosetting composition was 0.2 or more, and thermosetting composition NK-25 (Example 25), in which the molar ratio of the alcohol compound to the blocked isocyanate groups contained in the thermosetting composition was less than 0.2, thermosetting compositions NK-5 to 7 tended to have better storage stability.

[0205] As shown in Tables 2 and 6 above, in a comparison between thermosetting compositions NK-1 to 3 (Examples 1 to 3), in which the molar ratio of the alcohol compound to the blocked isocyanate groups contained in the thermosetting composition is 20 or less, and thermosetting composition NK-26 (Example 26), in which the molar ratio of the alcohol compound to the blocked isocyanate groups contained in the thermosetting composition is higher than 20, thermosetting compositions NK-1 to NK-3 tended to have better low-temperature curing properties when formed into a resin film.

[0206] As shown in Tables 2, 3, and 6 above, in a comparison between thermosetting compositions NK-5 to 7 (Examples 5 to 7), in which the molar ratio of the alcohol compound to the blocked isocyanate groups contained in the thermosetting composition is 20 or less, and thermosetting composition NK-27 (Example 27), in which the molar ratio of the alcohol compound to the blocked isocyanate groups contained in the thermosetting composition is higher than 20, thermosetting compositions NK-5 to NK-7 tended to have better low-temperature curing properties when formed into a resin film.

[0207] As shown in Tables 2 and 6 above, in a comparison between thermosetting composition NK-1 (Example 1), in which one ester moiety of the malonic acid ester of structural unit (I) is an isopropyl group and both two ester moieties of the malonic acid ester of structural unit (II) are isopropyl groups, and thermosetting composition NK-28 (Example 28), in which one ester moiety of the malonic acid ester of structural unit (I) is an ethyl group and both two ester moieties of the malonic acid ester of structural unit (II) are ethyl groups, thermosetting composition NK-1 tended to have better storage stability.

[0208] As shown in Tables 3 and 6 above, in a comparison between thermosetting composition NK-5 (Example 5), in which one ester moiety of the malonic acid ester of structural unit (I) is an isopropyl group and both two ester moieties of the malonic acid ester of structural unit (II) are isopropyl groups, and thermosetting composition NK-29 (Example 29), in which one ester moiety of the malonic acid ester of structural unit (I) is an ethyl group and both two ester moieties of the malonic acid ester of structural unit (II) are ethyl groups, thermosetting composition NK-5 tended to have better storage stability.

[0209] As shown in Tables 2, 4, 5, and 7 above, in a comparison between thermosetting compositions NK-1, 17, and 19 (Examples 1, 17, and 19) in which the blocked polyisocyanate component was modified with poly(oxyalkylene) ether in a proportion of 1 mol % or more and less than 20 mol %, and thermosetting composition NK-30 (Example 30) in which the blocked polyisocyanate component was not modified with poly(oxyalkylene) ether, the thermosetting compositions NK-1, 17, and 19 tended to have better storage stability.

[0210] As shown in Tables 2, 4, 5, and 7 above, in a comparison between thermosetting compositions NK-1, 17, and 19 (Examples 1, 17, and 19) in which the blocked polyisocyanate component was modified with poly(oxyalkylene) ether at a ratio of 1 mol % or more and less than 20 mol %, and thermosetting composition NK-32 (Example 32) in which the blocked polyisocyanate component was modified with poly(oxyalkylene) ether at a ratio of 20 mol %, the thermosetting compositions NK-1, 17, and 19 tended to have better low-temperature curing properties when formed into a resin film.

[0211] As shown in Tables 2, 4, and 7 above, in a comparison between thermosetting compositions NK-1 and 15 (Examples 1 and 15), in which the molar ratio of the structural unit represented by general formula (II) to the structural unit represented by general formula (I) (structural unit (II) / structural unit (I)) was in the range of 30 / 70 or more and 85 / 15, and thermosetting composition NK-31 (Example 31), in which (structural unit (II) / structural unit (I)) was less than 30 / 70, thermosetting compositions NK-1 and 15 tended to have better low-temperature curing properties when formed into a resin film.

Claims

1. A thermosetting composition comprising a blocked polyisocyanate component, a monohydric or dihydric alcohol compound, and a polyol, The blocked polyisocyanate component contains a blocked polyisocyanate compound having a structural unit represented by the following general formula (I): A thermosetting composition, wherein the polyol has at least three hydroxy groups in one molecule. 【Chemistry 1】 (In general formula (I), R １１ , R １２ and R １３ are each independently an alkyl group which may contain one or more substituents selected from the group consisting of a hydroxy group and an amino group, and R １１ , R １２ and R １３ The total number of carbon atoms in R is 4 or more and 20 or less. １４ , R １５ and R １６ are each independently a hydrogen atom or an alkyl group which may contain one or more substituents selected from the group consisting of a hydroxy group and an amino group. A wavy line represents a bond.

2. 2. The thermosetting composition according to claim 1, wherein the blocked polyisocyanate component comprises a blocked polyisocyanate compound derived from a polyisocyanate derived from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and one or more blocking agents, and the polyisocyanate has an average number of isocyanate groups of 3.5 or more.

3. The thermosetting composition according to claim 1 or 2, wherein the blocked polyisocyanate compound has a structural unit represented by the following general formula (I-1): 【Chemistry 2】 (In general formula (I-1), R １１１ , R １１２ and R １１３ are each independently an alkyl group which may contain one or more substituents selected from the group consisting of a hydroxy group and an amino group. １１１ , the R １１２ and the R １１３ The total number of carbon atoms in R is 4 or more and 20 or less. １１４ and R １１５ are each independently a hydrogen atom or an alkyl group which may contain one or more substituents selected from the group consisting of a hydroxy group and an amino group. A wavy line represents a bond.

4. 3. The thermosetting composition according to claim 1, wherein the blocked polyisocyanate component comprises a blocked polyisocyanate modified with a poly(oxyalkylene) ether represented by the following general formula (III): 【Transformation 3】 (In general formula (III), R ０１ is an alkylene group having 1 to 4 carbon atoms, and R ０２ is a hydroxy group or an alkyl group having 1 to 10 carbon atoms. The average number n1, which indicates the degree of polymerization of the alkylene oxide, is 4 to 30.

5. R in the general formula (I-1) １１１ , R １１２ , R １１３ , R １１４ , and R １１５ The thermosetting composition according to claim 3 , wherein each of the groups independently represents an unsubstituted alkyl group.

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