Hardening resin composition

Abstract

Provided is a curable resin composition that has high reactivity and can be cured at low temperature. A curable resin composition characterized by containing a resin component (A) having -COOR (where R is a C50 or lower alkyl group) and a hydroxyl group, and a transesterification catalyst (B), the transesterification catalyst (B) containing an imidazole compound and a zinc-containing compound.

Description

[Technical field]

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

[0002] The present inventors have been studying thermosetting resin compositions in which transesterification is used as a curing reaction (Patent Documents 1 to 3). Through such studies, it is becoming clear that it is possible to provide a thermosetting resin composition having performance equal to or superior to that of curing using a well-known curing agent such as a melamine resin or an isocyanate compound.

[0003] For such a thermosetting resin composition in which a transesterification reaction is used as a curing reaction, a composition with high reactivity is also required, that is, there are cases where it is required to cope with the cases where a component that inhibits the curing reaction is present in the system, where curing is required at a low temperature, or where curing is required in a short time. Therefore, the present inventors have proposed a thermosetting resin composition that can be cured at a relatively low temperature and a catalyst that can promote the reaction over a wide range (Patent Document 4).

[0004] Furthermore, such curable resin compositions are expected to be applied to various applications, and there is a demand for studying applications of the compositions to curable resin compositions that can be cured at lower temperatures and in shorter times, such as ambient-drying curable resin compositions that can be used for substrates such as large structures on which it is difficult to heat when forming a coating film, and that can form a coating film on such substrates inexpensively and easily. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6398026 [Patent Document 2] International Publication No. 2019 / 069783 [Patent Document 3] International Publication No. 2019 / 139069 [Patent Document 4] International Publication No. 2021 / 172307 Summary of the Invention [Problem to be solved by the invention]

[0006] In view of the above, an object of the present invention is to provide a curable resin composition which has high reactivity and can be cured at low temperatures. [Means for solving the problem]

[0007] The present invention relates to a polymerizable composition comprising a resin component (A) having -COOR (R is an alkyl group having 50 or less carbon atoms) and a hydroxyl group, and an ester exchange catalyst (B). Contains The transesterification catalyst (B) is a curable resin composition that contains a zinc-containing compound and an imidazole compound.

[0008] The zinc compound is preferably at least one zinc compound selected from the group consisting of zinc acetate, zinc octoate, zinc naphthenate, zinc gluconate, zinc acrylate, zinc acetylacetonate, zinc trifluoromethanesulfonate, and zinc oxide. The imidazole compound is preferably represented by the following general formula: [ka] (In the formula, R1 is an alkyl group, an alkenyl group, or an aromatic substituent having 10 or less carbon atoms, which may have a branched structure or a ring structure, and may have at least one selected from the group consisting of a hydroxyl group, an amino group, a carbonyl group, a cyano group, an ester group, an amide group, an ether group, and a nitro group. R2 to R4 are each independently a hydrogen atom, an alkyl group, an alkenyl group, or an aromatic substituent having 10 or less carbon atoms, and may have at least one selected from the group consisting of a hydroxyl group, an amino group, a carbonyl group, a cyano group, an ester group, an amide group, an ether group, and a nitro group.) Effect of the Invention

[0009] The curable resin composition of the present invention has high reactivity, can be cured at low temperatures, and can also be used as an ambient-dry type. [Brief description of the drawings]

[0010] [Figure 1] Rigid pendulum testing machine data for Example 1. [Diagram 2] Rigid pendulum tester data for Example 3. [Diagram 3] Rigid pendulum tester data for Example 4. [Figure 4] Rigid pendulum tester data for Example 5. [Diagram 5] Rigid pendulum tester data for Example 6. [Figure 6] Rigid pendulum tester data for Example 7. [Figure 7] Rigid pendulum tester data for Example 8. [Figure 8] Rigid pendulum tester data for Example 9. [Figure 9] Rigid pendulum testing machine data for Comparative Example 1. [Figure 10] Rigid pendulum testing machine data for Comparative Example 2. [Figure 11] Rigid pendulum testing machine data for Comparative Example 3. [Figure 12] Rigid pendulum tester data for Example 10. [Figure 13] Rigid pendulum tester data for Example 11. [Figure 14] Rigid pendulum tester data for Example 12. [Figure 15] Rigid pendulum testing machine data for Comparative Example 4. [Figure 16] Rigid pendulum testing machine data for Comparative Example 5. [Figure 17] FIG. 2 is a diagram showing a method for reading the hardening start temperature in the rigid pendulum test in this specification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described in detail below. The present invention relates to a thermosetting resin composition in which a transesterification reaction is used as a curing reaction, and by using a specific transesterification catalyst, the curing initiation temperature can be lowered, making it possible to apply the composition to an ambient dry type. Furthermore, the thermosetting resin composition is capable of obtaining sufficient physical properties such as strength even after curing.

[0012] In the present invention, it is important to use a catalyst containing a zinc-containing compound and an imidazole compound as the transesterification catalyst (B). By using a catalyst that combines these, the reactivity can be increased more than ever before, and the transesterification reaction can be achieved at a lower temperature. Although the mechanism by which such an effect is obtained is not clear, it is presumed that the imidazole compound improves the catalytic activity by coordinating with zinc.

[0013] The curing initiation temperature of the cured resin of the present invention is preferably 80° C. or lower, and more preferably 70° C. or lower. A curable resin composition having the above value of 70°C or less not only has high reactivity and can be cured at low temperatures, but also has suitable curing reactivity when used in applications requiring short-time curing or when used as a room-dry curable resin composition.

[0014] The above-mentioned hardening start temperature refers to the temperature at which the period begins to decrease when a rigid pendulum test is carried out under the condition of a temperature increase rate of 3°C / min, and is a value obtained by measuring the hardening start point as shown in Figure 17.

[0015] In order to obtain a curable resin composition that satisfies the above-mentioned performance, it is important to select the transesterification catalyst (B) to be used. That is, as a catalyst that is particularly effective in promoting reactivity, a catalyst containing the above-mentioned zinc-containing compound and an imidazole compound is selected, and thus a curable resin composition having the above-mentioned performance can be obtained.

[0016] In addition to the selection of the transesterification catalyst (B), a resin composition that is likely to exhibit curing reactivity may also be selected for the resin component (A) and appropriately combined to provide a curable resin composition that can be cured at a lower temperature.

[0017] The selection of the transesterification catalyst (B) and the selection of the resin composition, which are important in obtaining the curable resin composition of the present invention, will be described in detail below.

[0018] (Transesterification catalyst (B)) In the curable resin composition of the present invention, as described above, it is important to combine a zinc-containing compound and an imidazole compound as the transesterification catalyst (B).

[0019] Examples of the zinc-containing compound include zinc acetate, zinc octylate, zinc naphthenate, zinc gluconate, zinc acrylate, zinc acetylacetonate, zinc trifluoromethanesulfonate, zinc oxide, etc. Furthermore, a zinc cluster catalyst (for example, ZnTAC24 (trade name) manufactured by Tokyo Chemical Industry Co., Ltd.) can also be used. Furthermore, two or more of the above-mentioned compounds may be used in combination.

[0020] As the zinc-containing compound, a salt compound is particularly preferred, and the use of zinc acetylacetonate as the anion component is preferred in that it tends to provide a more excellent transesterification ability than the same kind of metal compound.

[0021] In addition, when zinc oxide is used, it is preferable to use zinc oxide dispersed in acetylacetone, which is believed to produce zinc acetylacetonate. The zinc oxide and acetylacetone are preferably contained in a ratio of 1:0.5 to 1:10 (weight ratio), which makes it possible to obtain particularly favorable results. The lower limit is more preferably 1:0.8, and even more preferably 1:1. The upper limit is more preferably 1:5, and even more preferably 1:3.

[0022] As the imidazole compound to be used in combination with the zinc-containing compound, a compound represented by the following general formula is preferable. [ka] (In the formula, R1 is an alkyl group, an alkenyl group, or an aromatic substituent having 10 or less carbon atoms which may have a branched structure or a ring structure, and may have at least one selected from the group consisting of a hydroxyl group, an amino group, a carbonyl group, a cyano group, an ester group, an amide group, an ether group, and a nitro group. R2 to R4 are each independently a hydrogen atom, an alkyl group, an alkenyl group, or an aromatic substituent having 10 or less carbon atoms, and may have at least one selected from the group consisting of a hydroxyl group, an amino group, a carbonyl group, a cyano group, an ester group, an amide group, an ether group, and a nitro group.)

[0023] Specific examples of the compound represented by the above general formula include 1-methylimidazole, 1-ethylimidazole, 1-propylimidazole, 1-butylimidazole, 1-vinylimidazole, 1-allylimidazole, 1-acetylimidazole, 1-phenylimidazole, 1-benzylimidazole, 1-(2-cyanoethyl)-2-methylimidazole, 1-(2-cyanoethyl)-2-phenylimidazole, 1,2-dimethylimidazole, 1-benzyl-2-methylimidazole, metronidazole, and 1-methylbenzimidazole. Among these, 1-methylimidazole is preferable in terms of production costs.

[0024] Further, examples of the compound represented by the above general formula include compounds obtained by addition reaction of imidazoles such as imidazole, 2-methylimidazole, 2-ethyl-4-methyl-imidazole, and benzimidazole with (meth)acrylic acid esters.

[0025] Examples of the (meth)acrylic acid ester used in the above-mentioned addition reaction include methyl (meth)acrylate, ethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-(dimethylamino)ethyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butyl (meth)acrylate, isobornyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, (poly)ethylene glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, etc. Among them, methyl acrylate is preferred in terms of reactivity. Among the above imidazoles, imidazole and 2-methylimidazole are preferred in terms of reactivity.

[0026] The above compound may be produced by a known production method, and the above imidazoles and (meth)acrylic acid esters may be used alone or in a mixture. For example, the above imidazoles and (meth)acrylic acid esters may be mixed and heated to 30 to 90°C. The imidazole may be heated to 30 to 90°C, possibly in the presence of a solvent, and the (meth)acrylic acid ester may be gradually added dropwise at the temperature. In this reaction, the ratio of the reactive amine hydrogen atom to the double bond product may be equivalent.

[0027] Moreover, the molecular weight of the imidazole compound used in the present invention is, for example, preferably not more than 500, and more preferably not more than 300. If the imidazole compound is within the above molecular weight range, high catalytic activity can be obtained. The molecular weight of the imidazole compound is preferably 80 or more. The imidazole compound is a monomer, and the molecular weight is calculated by analyzing the composition.

[0028] The present invention improves the catalytic activity of the transesterification reaction, so that the transesterification reaction can be carried out at a lower temperature. Therefore, the energy efficiency can be improved. Furthermore, the present invention can be used when carrying out the transesterification reaction of a compound with low heat resistance.

[0029] The transesterification catalyst (B) is also preferable because it can promote the reaction even in a system in which a carboxyl group is present, and can therefore be suitably used as a catalyst for the transesterification reaction in the waterborne curable resin composition.

[0030] The transesterification catalyst (B) is also preferred in that it can be used to make a curable resin composition to which a basic compound has been added. For example, when an amine compound is used as an additive such as a pigment dispersant, or when a paint is to be made water-soluble, it is widely practiced to introduce an acid group such as a carboxylic acid group or a sulfonic acid group into a resin and neutralize it with an amine compound to make it water-soluble. In this case, it is difficult to use it in combination with an acid catalyst, which is a problem that hinders the water-soluble conversion of a curable resin composition in which transesterification is a curing reaction. The transesterification catalyst (B) is also preferred in that it can be used to make a curable resin composition to which a basic compound has been added, since it can cause a good curing reaction without using an acid catalyst.

[0031] In addition, even when the curable resin composition of the present invention is used as a solvent-based coating composition, it may be used in combination with water-based coating as a part of the layers of the multi-layer coating film.In this case, when the multi-layer coating film is simultaneously heated and cured, amine, ammonia, etc. may be generated from the other layers that form the multi-layer coating film.Even in such a case, the above catalyst is preferable because it can perform good curing.

[0032] The transesterification catalyst preferably contains a zinc-containing compound (B-1) and an imidazole compound (B-2) in a ratio of (B-1):(B-2)=100:1 to 1:100 (weight ratio). By mixing in such a ratio, particularly favorable results can be obtained. The lower limit is more preferably 50:1, and even more preferably 10:1. The upper limit is more preferably 1:50, and even more preferably 1:10.

[0033] The zinc-containing compound (B-1) is preferably contained in a proportion of 0.01 to 50% by weight based on the amount of compounds involved in the reaction in the reaction system when the reaction is caused. The imidazole compound (B-2) is preferably contained in an amount of 0.01 to 50% by weight based on the amount of compounds involved in the reaction in the reaction system when the reaction is caused.

[0034] In the present invention, a basic compound such as diazabicycloundecene (DBU), diazabicyclononene (DBN), diazabicyclooctane (DABCO), tetrabutylammonium hydroxide, tetraethylammonium hydroxide, or tetramethylammonium hydroxide may be used in combination with the above transesterification catalyst.

[0035] (Resin Composition) The resin composition that can be used in the curable resin composition of the present invention will be described in detail below. The composition of the curable resin composition is not limited to the following examples. Furthermore, the curable resin composition of the present invention also includes those that become resins by curing. That is, even if the composition itself contains only low molecular weight compounds, it includes those that change into resins by reaction.

[0036] The resin component (A) used in the present invention has a -COOR group (R is an alkyl group having 50 or less carbon atoms) and a hydroxyl group. That is, any known compound or novel compound having these functional groups can be used in the present invention. Examples of such resin components include acrylic resins, polyester resins, polyether resins, urethane resins, silicone resins, etc., each of which contains a necessary functional group. In addition, the resins may be a mixture of these resins. Furthermore, at least a part of the components may be a low molecular weight compound.

[0037] The resin component may be a mixture of a compound (A-1) having two or more -COOR (R is an alkyl group having 50 or less carbon atoms) groups and a compound (A-2) having a hydroxyl group, or the resin component may be a compound (A-3) having one or more -COOR (R is an alkyl group having 50 or less carbon atoms) groups and one or more hydroxyl groups in part or in whole. Furthermore, the resin composition may contain (A-1) and / or (A-2) in addition to the resin composition essentially containing (A-3).

[0038] R in the resin of the present invention may be primary, secondary, or tertiary, so long as it has a carbon number of 50 or less, but is more preferably primary or secondary, and most preferably primary. More specifically, those having known ester groups such as methyl ester group, ethyl ester group, benzyl ester group, n-propyl ester group, isopropyl ester group, n-butyl ester group, isobutyl ester group, sec-butyl ester group, t-butyl group, etc. can be used. Since the above R is preferably generated as an alcohol during the transesterification reaction and volatilized, the alkyl group preferably has 20 or less carbon atoms, more preferably 10 or less. In addition, the boiling point of the alcohol volatilized in the curing reaction is preferably 300°C or less, more preferably 200°C or less.

[0039] Examples of resins and low molecular weight compounds that can be used in the present invention are given below. The present invention is not limited to those using the following resins and low molecular weight compounds, and the following examples and the compounds having the above functional groups can be used in appropriate combination as necessary.

[0040] (1) Polymers obtained by polymerization of unsaturated bonds Polymers obtained by polymerization of unsaturated bonds, such as acrylic resins, are widely used in the field of thermosetting resins such as paints and adhesives, and if a monomer having a hydroxyl group or an alkyl ester group is used, these functional groups will be present in the resin in the proportion of the monomer used. Therefore, it is easy to control the amount of functional groups in the resin and adjust the physical properties of the resin, and it can be easily used for the purpose of the present invention. In particular, when a hydroxyl group or an alkyl ester group is to be introduced, it can be introduced using the following monomers (1-1) and (1-2).

[0041] (1-1) Hydroxyl group-containing monomer The hydroxyl group-containing monomer is not particularly limited, and examples thereof include the following. Various hydroxyl-containing vinyl ethers such as 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 3-hydroxybutyl vinyl ether, 2-hydroxy-2-methylpropyl vinyl ether, 5-hydroxypentyl vinyl ether or 6-hydroxyhexyl vinyl ether; or addition reaction products of these various vinyl ethers with ε-caprolactone; Various hydroxyl-containing allyl ethers such as 2-hydroxyethyl (meth)allyl ether, 3-hydroxypropyl (meth)allyl ether, 2-hydroxypropyl (meth)allyl ether, 4-hydroxybutyl (meth)allyl ether, 3-hydroxybutyl (meth)allyl ether, 2-hydroxy-2-methylpropyl (meth)allyl ether, 5-hydroxypentyl (meth)allyl ether or 6-hydroxyhexyl (meth)allyl ether; or addition reaction products of these various allyl ethers listed above with ε-caprolactone; or various hydroxyl group-containing (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, or polypropylene glycol mono(meth)acrylate; or the main component of an addition reaction between any of the above-listed (meth)acrylates and ε-caprolactone; and N-hydroxyalkyl(meth)acrylamides such as N-hydroxymethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, and N-hydroxybutyl(meth)acrylamide.

[0042] In addition, when the hydroxyl group-containing monomer as a monomer does not directly have a hydroxyl group, but has a hydroxyl group via a linking chain having 5 or more molecules, the hydroxyl group becomes more mobile in the resin, which is preferable in that the reaction occurs more easily.

[0043] (1-2) Alkyl ester group-containing monomer As the alkyl ester group-containing monomer, a great many types of monomers having an alkyl ester group and a polymerizable unsaturated bond are known, but typical examples include compounds represented by the following general formula:

[0044] (1-2-a) A compound represented by the following general formula (1): [ka] (In the formula, R4, R5, and R6 each represent a hydrogen atom, an alkyl group, a carboxyl group, or an alkyl ester group. R7 represents a hydrocarbon group having 50 or less carbon atoms.

[0045] Examples of such compounds represented by the general formula (1) include ester derivatives of known unsaturated carboxylic acids such as (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid.

[0046] The most typical monomer having an alkyl ester group and a polymerizable unsaturated bond represented by the above general formula (1) is an ester of (meth)acrylic acid and an alcohol, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, benzyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, lauryl (meth)acrylate, and the like.

[0047] The t-butyl (meth)acrylate is a tertiary alkyl ester, and therefore the transesterification reaction is fast, and the curing reaction proceeds efficiently. Therefore, it has better crosslinking reactivity than primary alkyl esters and secondary alkyl esters, and is a very preferable raw material for providing an ester group that achieves the object of the present invention.

[0048] (1-2-b) A compound represented by the following general formula (4): [ka] n1:1~10 (In the formula, R4, R5, and R6 are the same or different and each is a hydrogen atom, an alkyl group, a carboxyl group, an alkyl ester group, or a structure represented by the following R7-[COOR8]n1. R7 is an aliphatic, alicyclic or aromatic alkylene group which has 50 or less atoms in its main chain and which may have one or more functional groups selected from the group consisting of an ester group, an ether group, an amide group, and a urethane group in the main chain and which may have a side chain. R8 is an alkyl group having 50 or less carbon atoms. In the compound represented by the above general formula (4), the R7-[COOR8]n1 group may have a lactone structure represented by the following general formula (4-1):

[0049] [ka] (Rx is a hydrocarbon group having 2 to 10 carbon atoms which may have a branched chain.)

[0050] The polymer obtained by using the monomer represented by the above general formula (4) can be made to have particularly excellent transesterification reactivity, and is therefore particularly preferred for obtaining a resin composition having a curing initiation temperature of 130°C or less and a gel fraction of 80% or more when cured under the conditions of baking at 150°C for 30 minutes.

[0051] In the monomer represented by the above general formula (4), R8 preferably has a primary or secondary alkyl ester. The primary or secondary alkyl ester group derived from such a monomer is easily reacted with a hydroxyl group, and therefore the object of the present invention can be sufficiently achieved.

[0052] Such a compound can obtain a polymer by polymerization reaction due to an unsaturated bond. When the polymer thus obtained is used in a thermosetting resin composition in which an ester exchange reaction is used as a curing reaction, the main chain formed based on the polymerization of the unsaturated bond and the alkyl ester group are separated via a linking group. Therefore, the alkyl ester group can move relatively freely. Therefore, the present inventors have found that the alkyl ester group and the hydroxyl group are easily brought close to each other, improving the reactivity of the ester exchange reaction. By improving the reactivity of the ester exchange reaction in this way, it is possible to realize short-time curing and a reduction in the curing temperature, and the usefulness of the thermosetting resin composition by the ester exchange reaction can be improved.

[0053] The alkyl ester group is not particularly limited, and may be one having a known ester group such as a methyl ester group, an ethyl ester group, a benzyl ester group, an n-propyl ester group, an isopropyl ester group, an n-butyl ester group, an isobutyl ester group, or a sec-butyl ester group. The alkyl group preferably has 50 or less carbon atoms. Since the alkyl group is preferably generated as an alcohol during the transesterification reaction and volatilizes, the alkyl group preferably has 20 or less carbon atoms, and more preferably has 10 or less carbon atoms. The boiling point of the alcohol volatilized in the curing reaction is preferably 300° C. or less, and more preferably 200° C. or less.

[0054] The alkyl group in the alkyl ester group (i.e., R8 in the general formula (4)) is an alkyl group having 50 or less carbon atoms, more preferably in the range of 1 to 20 carbon atoms, even more preferably in the range of 1 to 10 carbon atoms, and even more preferably in the range of 1 to 6 carbon atoms. It is most preferably in the range of 1 to 4. By keeping it within such a range, the curing reaction can be favorably progressed, which is preferable.

[0055] The present invention also includes cases where the alkyl ester group is a lactone group. The ester group of such a lactone group can also cause the transesterification reaction of the present invention and can be used in the curing reaction. Such a compound has the chemical structure of (4-1) above.

[0056] More specifically, the structure represented by the above general formula (4) is, for example,

[0057] [ka] n2:1~10 (Wherein, R9 is H or a methyl group. R 10represents an alkylene group having 48 or less atoms in its main chain, which may have an ester group, an ether group and / or an amide group in the main chain and which may have a side chain. R 11 is an alkyl group having 50 or less carbon atoms.) Such compounds are derivatives of (meth)acrylic acid, and can be obtained by known synthesis methods using (meth)acrylic acid or its derivatives as raw materials.

[0058] Above R 10 The number of atoms in the main chain of R is more preferably 40 or less, further preferably 30 or less, and further preferably 20 or less. 10 The atoms that may be included in the main chain of R are not particularly limited, and may include oxygen atoms, nitrogen atoms, sulfur atoms, silicon atoms, etc. in addition to carbon atoms. More specifically, R 10 The main chain may contain, in addition to an alkyl group, an ether group, an ester group, an amino group, an amide group, a thioether group, a sulfonate group, a thioester group, a siloxane group, or the like.

[0059] More specifically, the structure represented by the above general formula (5) includes, for example, a compound represented by the following general formula (12).

[0060] [ka] (In the formula, R 20 is an alkyl group having 1 to 50 carbon atoms. R 21 represents an alkylene group having 44 or less atoms in the main chain, which may have an ester group, an ether group and / or an amide group in the main chain and which may have a side chain. R 22 is H or a methyl group. R 23 is an alkyl group having 50 or less carbon atoms. R 24 is H or a methyl group. n7 is 0 or 1. n8 is 1 or 2.)

[0061] The compound represented by the above general formula (12) is a compound synthesized by reacting a compound that generates an active anion, such as a malonic acid ester or an acetoacetic acid ester, having an unsaturated bond in the molecule, with an unsaturated compound having an alkyl ester group.

[0062] That is, malonic acid esters and acetoacetate esters have a methylene group sandwiched between carboxy carbons, and this methylene group is easily anionized and is widely known to easily cause anionic reactions. A compound having both an unsaturated group and an alkyl ester group can be synthesized by reacting such a compound having an unsaturated bond in the alkyl group of a malonic acid ester or acetoacetate ester (for example, an ester compound of malonic acid or acetoacetic acid with an unsaturated monomer having a hydroxyl group, which will be described in detail below as a "hydroxyl group-containing monomer") with an alkyl ester compound having an unsaturated group.

[0063] Compounds having such a structure can be easily modified only with alkyl ester groups using widely used raw materials, and as a result, the curing reactivity can be easily adjusted. In addition, the compounds are particularly preferable in that the curing reactivity can be adjusted by changing the reaction rate with the active methylene group.

[0064] The compound that can be used as the "alkyl ester compound having an unsaturated group" used in the above reaction is not particularly limited, and examples of the compound that can be used include (meth)acrylic acid alkyl esters, methylenemalonic acid alkyl esters, and lactone compounds having an unsaturated group (e.g., γ-crotonolactone, 5,6-dihydro-2H-pyran-2-one).

[0065] The reaction can be carried out under basic conditions, for example, by reaction in an organic solvent in the presence of an alkali metal salt and a crown ether. An example of such a synthesis reaction is shown below.

[0066] [ka]

[0067] The alkyl ester compound represented by the above general formula (4) can also be obtained by esterification of the corresponding carboxylic acid. That is, a compound represented by the following general formula (4-2) is a carboxylic acid corresponding to the alkyl ester compound represented by the above general formula (4).

[0068] [ka] n1:1~10 (In the formula, R4, R5, and R6 are the same or different and each is a hydrogen atom, an alkyl group, a carboxyl group, an alkyl ester group, or a structure represented by the following R7-[COOH]n1. R7 is an aliphatic, alicyclic or aromatic alkylene group having 50 or less atoms in the main chain, which may have one or more functional groups selected from the group consisting of an ester group, an ether group, an amide group and a urethane group in the main chain, and which may have a side chain.

[0069] There are known compounds represented by the above general formula (4-2). By subjecting such known compounds to a normal esterification reaction (for example, a reaction with an alcohol corresponding to the alkyl group of the desired alkyl ester), the unsaturated group-containing ester compound used in the present invention can be obtained.

[0070] (1-2-bX) The compound represented by the above general formula (4) may be a compound having a functional group and an unsaturated group represented by the following general formula (31).

[0071] [ka]

[0072] n=0~20 R1 is an alkyl group having 50 or less carbon atoms. R3 is hydrogen or an alkyl group having 10 or less carbon atoms.

[0073] That is, in the compound represented by general formula (4), the COOR8 group may have a structure represented by the above general formula (31).

[0074] The ester group represented by the above general formula (31) has high reactivity in transesterification reactions, for reasons unknown, and therefore, by using an ester compound having this functional group as a part or the whole of the resin component, a thermosetting resin composition having better curing performance than ever before can be obtained. For this reason, it can be suitably used as a resin for obtaining a thermosetting resin composition which has a curing initiation temperature of 130°C or lower and a gel fraction of 80% or higher when cured under the conditions of baking at 150°C for 30 minutes.

[0075] (Regarding the structure of general formula (31)) The structure of the above general formula (31) is based on an α-substituted carboxylate skeleton. In the general formula (31), n ​​is an integer of 0 to 20. The lower limit of n is more preferably 0. The upper limit of n is more preferably 5. Furthermore, it may be a mixture of a plurality of components having different values ​​of n in the above general formula (31). In this case, the average value n, nav, is preferably 0 to 5. The lower limit of nav is more preferably 1. The upper limit of nav is more preferably 3. The nav can be measured by NMR analysis. Furthermore, the value of n can also be measured by NMR analysis.

[0076] In the above general formula (31), any alkyl group having 50 or less carbon atoms can be used as R1, and it may be primary, secondary, or tertiary.

[0077] The alkyl group in the alkyl ester group (i.e., R1 in the general formula above) is an alkyl group having 50 or less carbon atoms, more preferably in the range of 1 to 20 carbon atoms, even more preferably in the range of 1 to 10 carbon atoms, and even more preferably in the range of 1 to 6 carbon atoms. It is most preferably in the range of 1 to 4. By keeping it within such a range, the curing reaction can be favorably progressed, which is preferable.

[0078] Specific examples of the alkyl ester group that can be used include those having known ester groups, such as a methyl ester group, an ethyl ester group, a benzyl ester group, an n-propyl ester group, an isopropyl ester group, an n-butyl ester group, an isobutyl ester group, a sec-butyl ester group, and a t-butylalkyl group.

[0079] The compound having the functional group (31) can be prepared by reacting a carboxylic acid or carboxylate compound corresponding to the structure of the target compound with a compound represented by the following general formula (32):

[0080] [ka]

[0081] (X represents a halogen or a hydroxyl group) This can be obtained by reacting an ester compound having an active group X introduced at the α-position of the carbonyl group having the structure shown below. This can be expressed by the general formula as follows.

[0082] [ka]

[0083] In the above general formula, the compound that can be used as the raw material represented by general formula (33) can be any carboxylic acid or carboxylic acid derivative that can cause the above-mentioned reaction. Examples of carboxylic acid derivatives include Y being OM (carboxylate), OC=OR (acid anhydride), Cl (acid chloride), etc. When Y=OM is a carboxylate, examples of the carboxylate include sodium salt, potassium salt, amine salt, zinc salt, etc. When used as a monomer for a polymer, a compound having an unsaturated group can be used as the compound represented by general formula (33).

[0084] The compound represented by the above general formula (32) can be a compound having a skeleton corresponding to the target structure represented by the general formula (31).

[0085] In addition, the compound represented by the above general formula (32) is not particularly limited in its manufacturing method. Among the compounds represented by the above general formula (32), the compound with n=0 is a compound having an active group represented by X at the α position, and examples thereof include various α-hydroxy acids and α-halogenated carboxylic acids. Specifically, examples thereof include methyl chloroacetate, ethyl chloroacetate, methyl bromoacetate, ethyl bromoacetate, t-butyl bromoacetate, methyl 2-chloropropionate, methyl glycolate, methyl lactate, ethyl lactate, and butyl lactate.

[0086] Among the compounds represented by the above general formula (32), for the compounds where n is 1 or more, an example of the production method is shown below. It should be noted that the content shown below is only one example of the production method, and the present invention is not limited to the compounds obtained by the production method described below.

[0087] For example, it can be obtained by reacting a carboxylic acid having a halogen at the α-position, its salt or its derivative with a carboxylic acid alkyl ester having a halogen or a hydroxyl group at the α-position. This can be represented by the following general formula.

[0088] [ka]

[0089] Examples of the carboxylic acid having a halogen at the α-position, its salt or its derivative include an alkali metal salt of the carboxylic acid (potassium salt, sodium salt, etc.), an acid anhydride, an acid chloride, etc. As the compound represented by the above general formula (34), specifically, sodium chloroacetate, etc. can be used.

[0090] Examples of the carboxylic acid alkyl ester having a halogen or hydroxyl group at the α-position include alkyl esters of α-substituted carboxylic acid compounds such as chloroacetic acid, bromoacetic acid, lactic acid, etc. The alkyl group of the alkyl ester is not particularly limited as long as it has 1 to 50 carbon atoms. Such an alkyl group may be any of primary, secondary and tertiary alkyl groups, and specific examples thereof include a methyl group, an ethyl group, a benzyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group.

[0091] In the above reaction, it is preferable that X1 and X2 are different. It is preferable that these are different functional groups with different reactivities, and that the combination of functional groups is selected so that X1 remains unreacted. Specifically, a combination of X1 being a chloro group and X2 being a bromo group is particularly preferable.

[0092] In addition, the value of n can be adjusted by adjusting the mixing ratio of the two raw materials in the above reaction. In the above reaction, a mixture of multiple compounds having different n is generally obtained. The compound represented by the above general formula (4) may be purified to use only those having a specific value of n, or it may be a mixture of multiple compounds having different values ​​of n.

[0093] The chemical structure represented by the above general formula (31) can be formed by reacting the compound represented by the above general formula (32) with various carboxylic acid compounds. Therefore, if a carboxylic acid having an unsaturated group is used as the "compound having a carboxylic acid group", a compound having a functional group and a polymerizable unsaturated group represented by the above general formula (31) can be obtained.

[0094] Specifically, for example, when the compound represented by the above general formula (32) is reacted with (meth)acrylic acid, a compound represented by the following general formula (36) is obtained. [ka] (In the formula, R1 is an alkyl group having 50 or less carbon atoms. R2 is hydrogen or a methyl group. R3 is hydrogen or an alkyl group having 10 or less carbon atoms. n is 1 to 20)

[0095] R1 in the compound represented by the above general formula (36) may be primary, secondary, or tertiary, so long as it has 50 or less carbon atoms. However, it is more preferably primary or secondary, and most preferably primary. Moreover, it is most preferable that n=0.

[0096] (1-2-bY) The compound represented by the above general formula (4) may be a compound having a functional group represented by the following general formula (41) and / or a functional group represented by the following general formula (42), and an unsaturated group.

[0097] [ka]

[0098] [ka] (In both of the above general formula (41) and general formula (42), R1 is an alkyl group having 50 or less carbon atoms. R2 is an alkylene group having 50 or less carbon atoms that may contain oxygen or nitrogen atoms.

[0099] That is, in the compound represented by general formula (4), the COOR8 group may have a structure as represented by the above general formula (41) and / or a structure as represented by general formula (42). For this reason, it can be suitably used as a resin for obtaining a thermosetting resin composition which has a curing initiation temperature of 130°C or lower and a gel fraction of 80% or higher when cured under the conditions of baking at 150°C for 30 minutes.

[0100] The alkyl group in the alkyl ester group (i.e., R1 in the general formula above) is an alkyl group having 50 or less carbon atoms, more preferably in the range of 1 to 20 carbon atoms, even more preferably in the range of 1 to 10 carbon atoms, and even more preferably in the range of 1 to 6 carbon atoms. It is most preferably in the range of 1 to 4. By keeping it within such a range, the curing reaction can be favorably progressed, which is preferable.

[0101] Specific examples of the alkyl group that can be used include those having known ester groups, such as a methyl ester group, an ethyl ester group, a benzyl ester group, an n-propyl ester group, an isopropyl ester group, an n-butyl ester group, an isobutyl ester group, a sec-butyl ester group, and a t-butylalkyl group.

[0102] The R2 group in the above general formula (41) is an alkylene group having 50 or less carbon atoms which may partially contain oxygen atoms or nitrogen atoms, and specifically may contain a methylene group, ethylene group, n-propylene group, i-propylene group, n-butylene group, or a cyclic structure such as a benzene ring or a cyclohexyl ring (carbon chain of 1 to 50). Among these, an ethylene group is particularly preferred in terms of inexpensive raw materials and excellent reactivity.

[0103] An example of a compound having a structure represented by the above general formula (41) is a compound represented by the following general formula (43).

[0104] [ka] (In the formula, R1 is an alkyl group having 50 or less carbon atoms. R2 is an alkylene group having 50 or less carbon atoms which may partially contain oxygen atoms or nitrogen atoms. R3 is hydrogen or a methyl group.

[0105] Among the ester compounds represented by the above general formula (43), the ester compounds represented by the following general formula (45) are more preferred.

[0106] [ka]

[0107] The method for producing the ester compound having the functional group represented by the general formula (41) is not particularly limited, but may be a method of reacting a compound having an alkyl ester group and a carboxyl group with an epoxy compound. This reaction is represented by the following general formula:

[0108] [ka]

[0109] In the above reaction, the compound having an alkyl ester group and a carboxyl group can be produced, for example, by the reaction of an acid anhydride with an alcohol, as in the following reaction.

[0110] [ka]

[0111] The acid anhydride used as the raw material in the reaction represented by the above general formula (52) is not particularly limited, and for example, various dibasic acid anhydrides having a cyclic structure such as succinic anhydride, maleic anhydride, phthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, benzoic anhydride, itaconic anhydride, etc. The reaction represented by the above general formula (52) is a well-known general reaction, and the reaction conditions thereof can be general conditions.

[0112] The compound having an alkyl ester group and a carboxyl group used in the synthesis method represented by the above general formula (51) is not limited to the compound obtained by the method represented by the above general formula (52), and may be obtained by any other method.

[0113] In the synthesis method represented by the above general formula (51), an epoxy compound is used as an essential component. The epoxy compound is not particularly limited as long as it has an unsaturated double bond and an epoxy group, and any epoxy compound can be used.

[0114] The epoxy compound that can be used in the above-mentioned reaction may be any known epoxy compound, such as glycidyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether, trimethylolpropane triglycidyl ether, etc.

[0115] For example, by using epichlorohydrin, it is possible to introduce epoxy groups into compounds having various skeletons by reacting it with a phenol compound, a carboxylic acid compound, a hydroxyl group-containing compound, etc. By carrying out the above-mentioned reaction with any of these epoxy compounds, it is possible to obtain a compound having a functional group represented by the above-mentioned general formula (41). The general formula for such a reaction is shown below.

[0116] [ka]

[0117] Examples of the hydroxycarboxylic acid having a carboxyl group and an unsaturated group include (meth)acrylic acid.

[0118] Furthermore, the above-mentioned epoxy compound may be a cyclic epoxy compound. That is, when a cyclic epoxy compound is used as the epoxy compound, a compound having a structure represented by general formula (42) can be obtained by the following reaction.

[0119] [ka]

[0120] Examples of alicyclic epoxy compounds that can be used in the above general formula include 3,4-epoxycyclohexylmethyl methacrylate, 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, and the like.

[0121] Specific examples of the functional group represented by the general formula (41) and / or the compound represented by the general formula (42), and the compound having an unsaturated group, include compounds represented by the following general formulas.

[0122] [ka]

[0123] Examples of specific chemical structures of the compounds represented by general formula (4) that can be synthesized by the above-mentioned method are shown below. Note that the present invention is not limited to the compounds shown below.

[0124] [ka] JPEG0007633729000025.jpg139170 (In the above general formula, R represents an alkyl group having 50 or less carbon atoms)

[0125] In the compound represented by the above general formula, R in the general formula is an alkyl group having 50 or less carbon atoms, more preferably in the range of 1 to 20 carbon atoms, even more preferably in the range of 1 to 10 carbon atoms, and even more preferably in the range of 1 to 6. Most preferably in the range of 1 to 4. By setting it within such a range, it is preferable in that the curing reaction can be suitably progressed.

[0126] (1-3) Other monomers The polymer used in the present invention may be a homopolymer or copolymer consisting of only the monomers shown in (1-1) or (1-2) above, or a copolymer using other monomers. The other monomers that can be used in the above polymer are not particularly limited, and any monomer having a polymerizable unsaturated group can be used. Examples of the monomers that can be used are shown below.

[0127] Various α-olefins, such as ethylene, propylene or butene-1; Various halogenated olefins, excluding fluoroolefins, such as vinyl chloride or vinylidene chloride; Various aromatic vinyl compounds, such as styrene, alpha-methylstyrene or vinyltoluene; Various amino group-containing amide-based unsaturated monomers such as N-dimethylaminoethyl(meth)acrylamide, N-diethylaminoethyl(meth)acrylamide, N-dimethylaminopropyl(meth)acrylamide or N-diethylaminopropyl(meth)acrylamide; Various dialkylaminoalkyl (meth)acrylates, such as dimethylaminoethyl (meth)acrylate or diethylaminoethyl (meth)acrylate; Various amino group-containing monomers such as tert-butylaminoethyl (meth)acrylate, tert-butylaminopropyl (meth)acrylate, aziridinylethyl (meth)acrylate, pyrrolidinylethyl (meth)acrylate, or piperidinylethyl (meth)acrylate; Various carboxyl group-containing monomers, such as (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid or fumaric acid; Various epoxy group-containing monomers, such as glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, or (meth)allyl glycidyl ether; Mono- or diesters of various α,β-unsaturated dicarboxylic acids, such as maleic acid, fumaric acid or itaconic acid, with monohydric alcohols having 1 to 18 carbon atoms; Monomers containing various hydrolyzable silyl groups, such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripoxysilane, vinylmethyldiethoxysilane, vinyltris(β-methoxyethoxy)silane, allyltrimethoxysilane, trimethoxysilylethyl vinyl ether, triethoxysilylethyl vinyl ether, methyldimethoxysilylethyl vinyl ether, trimethoxysilylpropyl vinyl ether, triethoxysilylpropyl vinyl ether, methyldiethoxysilylpropyl vinyl ether, γ-(meth)acryloyloxypropyltrimethoxysilane, γ-(meth)acryloyloxypropyltriethoxysilane or γ-(meth)acryloyloxypropylmethyldimethoxysilane; Various fluorine-containing α-olefins such as vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, bromotrifluoroethylene, pentafluoropropylene or hexafluoropropylene; or various fluorine atom-containing monomers such as various perfluoroalkyl perfluorovinyl ethers or (per)fluoroalkyl vinyl ethers (wherein the alkyl group has a carbon number of 1 to 18) such as trifluoromethyl trifluorovinyl ether, pentafluoroethyl trifluorovinyl ether or heptafluoropropyl trifluorovinyl ether; various alkyl vinyl ethers or substituted alkyl vinyl ethers, such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether, 2-ethylhexyl vinyl ether, chloromethyl vinyl ether, chloroethyl vinyl ether, benzyl vinyl ether or phenylethyl vinyl ether; Various cycloalkyl vinyl ethers, such as cyclopentyl vinyl ether, cyclohexyl vinyl ether or methylcyclohexyl vinyl ether; vinyl 2,2-dimethylpropanoate, vinyl 2,2-dimethylbutanoate, vinyl 2,2-dimethylpentanoate, vinyl 2,2-dimethylhexanoate, vinyl 2-ethyl-2-methylbutanoate, vinyl 2-ethyl-2-methylpentanoate, vinyl 3-chloro-2,2-dimethylpropanoate, and the like, as well as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl caprylate, vinyl caprate or vinyl laurate, C9 branched aliphatic vinyl carboxylates, C 10 A branched aliphatic vinyl carboxylate, C 11Examples of the vinyl esters include various aliphatic carboxylates, such as vinyl branched aliphatic carboxylate or vinyl stearate, which are represented by the formula:

[0128] In the present invention, the above-mentioned various monomers (1-1) to (1-3) can be combined and polymerized as necessary to produce a compound having both an alkyl ester group and a hydroxyl group, a compound having an alkyl ester group, or a compound having a hydroxyl group. Furthermore, the above-mentioned functional groups required for water solubility can be combined in a required ratio according to the purpose and introduced into the resin.

[0129] The above polymer can be produced by polymerization using any known method, without any particular limitation on the production method thereof. More specifically, the polymer can be produced by polymerization using a solution polymerization method in an organic solvent, an emulsion polymerization method in water, a mini-emulsion polymerization method in water, an aqueous solution polymerization method, a suspension polymerization method, a UV curing method, and the like.

[0130] Furthermore, when solution polymerization is carried out in an organic solvent, the polymer may then be made aqueous by a known operation, thereby making it in a form that can be used in the thermosetting resin composition of the present invention.

[0131] Alternatively, the polymer may be one in which a hydroxyl group and / or an alkyl ester group is introduced into a side chain by reacting a side chain functional group of a polymer obtained by polymerizing a composition containing the above-mentioned monomer. The reaction on the side chain is not particularly limited, and examples thereof include ester exchange, reaction with isocyanate, reaction with epoxy, reaction with silane, reaction with melamine resin, addition reaction, hydrolysis, dehydration condensation, and substitution reaction.

[0132] The molecular weight of the polymer is not particularly limited, and may be, for example, a weight average molecular weight of 3,000 to 1,000,000. The upper limit of the weight average molecular weight is more preferably 300,000, further preferably 100,000, and further preferably 50,000. The lower limit of the weight average molecular weight is more preferably 3,000, and further preferably 4,000. Examples of the acrylic resin include water-soluble acrylic resin having a weight-average molecular weight usually within the range of 5,000 to 100,000, preferably 5,000 to 50,000, and acrylic resin particles which are the dispersoid of an acrylic resin emulsion having a weight-average molecular weight of 50,000 or more, preferably 100,000 or more. The aqueous acrylic resin preferably contains a hydroxyl group, and preferably has a hydroxyl value generally within the range of 20 to 200 mgKOH / g, particularly 20 to 150 mgKOH / g, from the viewpoints of water dispersibility or compatibility with other components, curability of the coating film formed, etc. The aqueous acrylic resin preferably has an acid value generally within the range of 1 to 100 mgKOH / g, particularly 10 to 70 mgKOH / g.

[0133] Furthermore, the alkyl ester group is preferably contained in the mixture of each monomer in an amount of 5 to 95% by weight.

[0134] (2) Polyester polyol The polyester polyol can usually be produced by an esterification reaction or an ester exchange reaction between an acid component and an alcohol component. The acid component may be a compound that is commonly used as an acid component in the production of a polyester resin, such as an aliphatic polybasic acid, an alicyclic polybasic acid, an aromatic polybasic acid, or the like, as well as an anhydride and an ester thereof.

[0135] In addition, the polyester resin may be one obtained by reacting an α-olefin epoxide such as propylene oxide or butylene oxide, or a monoepoxy compound such as Cardura E10 (trade name, manufactured by Japan Epoxy Resins, glycidyl ester of synthetic highly branched saturated fatty acid) with an acid group of the polyester resin.

[0136] The aqueous polyester resin may be urethane-modified.

[0137] The polyester resin may have a weight average molecular weight within the range of 2,000 to 100,000, and preferably 3,000 to 30,000. The weight average molecular weight of such a polyester resin may be measured by the same method as that for the weight average molecular weight of the acrylic resin.

[0138] Examples of the aliphatic polybasic acids and their anhydrides and esters generally include aliphatic compounds having two or more carboxyl groups in one molecule, acid anhydrides of the aliphatic compounds, and esters of the aliphatic compounds, such as aliphatic polycarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, octadecanedioic acid, citric acid, and butanetetracarboxylic acid; anhydrides of the aliphatic polycarboxylic acids; esters of the aliphatic polycarboxylic acids with lower alkyl groups having from about 1 to about 4 carbon atoms; and any combination thereof. From the viewpoint of the smoothness of the resulting coating film, the aliphatic polybasic acid is preferably adipic acid and / or adipic anhydride.

[0139] The alicyclic polybasic acids and their anhydrides and esters are generally compounds having one or more alicyclic structures and two or more carboxyl groups in one molecule, acid anhydrides of the compounds, and esters of the compounds. The alicyclic structures are mainly 4- to 6-membered ring structures. The alicyclic polybasic acids and their anhydrides and esters include, for example, alicyclic polycarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, 3-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, and 1,3,5-cyclohexanetricarboxylic acid; anhydrides of the alicyclic polycarboxylic acids; esters of the alicyclic polycarboxylic acids with lower alkyls having about 1 to about 4 carbon atoms, and any combination thereof.

[0140] As the above-mentioned alicyclic polybasic acids and their anhydrides and esters, from the viewpoint of the smoothness of the resulting coating film, 1,2-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic anhydride, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid and 4-cyclohexene-1,2-dicarboxylic anhydride are preferred, and 1,2-cyclohexanedicarboxylic acid and / or 1,2-cyclohexanedicarboxylic anhydride are more preferred.

[0141] The above aromatic polybasic acids, and their anhydrides and esters are generally aromatic compounds having two or more carboxyl groups in one molecule, acid anhydrides of the above aromatic compounds, and esters of the above aromatic compounds. Examples of the aromatic polybasic acids include phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, trimellitic acid, pyromellitic acid, and other aromatic polybasic carboxylic acids; anhydrides of the above aromatic polybasic carboxylic acids; esters of the above aromatic polybasic carboxylic acids with lower alkyl groups having from about 1 to about 4 carbon atoms, and any combination thereof. As the aromatic polybasic acids and their anhydrides and esters, phthalic acid, phthalic anhydride, isophthalic acid, trimellitic acid, and trimellitic anhydride are preferred.

[0142] Further, examples of the acid component include acid components other than the aliphatic polybasic acids, alicyclic polybasic acids, and aromatic polybasic acids, such as fatty acids such as coconut oil fatty acids, cottonseed oil fatty acids, hempseed oil fatty acids, rice bran oil fatty acids, fish oil fatty acids, tall oil fatty acids, soybean oil fatty acids, linseed oil fatty acids, tung oil fatty acids, rapeseed oil fatty acids, castor oil fatty acids, dehydrated castor oil fatty acids, and safflower oil fatty acids; monocarboxylic acids such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, p-tert-butylbenzoic acid, cyclohexanoic acid, and 10-phenyloctadecanoic acid; hydroxycarboxylic acids such as lactic acid, 3-hydroxybutanoic acid, and 3-hydroxy-4-ethoxybenzoic acid, and any combination thereof.

[0143] Examples of the alcohol component include polyhydric alcohols having two or more hydroxyl groups in one molecule, such as ethylene glycol, propylene glycol, diethylene glycol, trimethylene glycol, tetraethylene glycol, triethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol, 3-methyl-1,2-butanediol, 1,1,1-trimethylolpropane, 2-butyl 2-ethyl-1,3-propanediol, 1,2-pentanediol, 1,5-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 2,3-dimethyltrimethylene glycol, tetramethylene glycol, 3-methyl-4,3-pentanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,6-hexanediol, 1,5-hexanediol, 1,4-hexanediol, 2,5-hexanediol, neopentyl glycol polylactone diols obtained by adding a lactone compound such as ε-caprolactone to the above dihydric alcohols; ester diol compounds such as bis(hydroxyethyl)terephthalate; polyether diol compounds such as alkylene oxide adducts of bisphenol A, polyethylene glycol, polypropylene glycol, and polybutylene glycol; trihydric or higher alcohols such as glycerin, trimethylolethane, trimethylolpropane, diglycerin, triglycerin, 1,2,6-hexanetriol, pentaerythritol, dipentaerythritol, tris(2-hydroxyethyl)isocyanuric acid, sorbitol, and mannitol; polylactone polyol compounds obtained by adding a lactone compound such as ε-caprolactone to the above trihydric or higher alcohols; and fatty acid esters of glycerin.

[0144] Further, examples of the alcohol component include alcohol components other than the polyhydric alcohols, for example, monoalcohols such as methanol, ethanol, propyl alcohol, butyl alcohol, stearyl alcohol, and 2-phenoxyethanol; and alcohol compounds obtained by reacting monoepoxy compounds such as propylene oxide, butylene oxide, and "Cardura E10" (product name, manufactured by HEXION Specialty Chemicals, glycidyl ester of synthetic highly branched saturated fatty acid) with acids.

[0145] The polyester polyol is not particularly limited and can be produced according to a conventional method. For example, the acid component and the alcohol component are heated in a nitrogen gas flow at about 150 to about 250° C. for about 5 to about 10 hours to carry out an esterification reaction or an ester exchange reaction between the acid component and the alcohol component, thereby producing the polyester polyol.

[0146] The carboxyl groups of the polyester resin can be neutralized with the above-mentioned basic substances as necessary.

[0147] The aqueous polyester resin preferably contains a hydroxyl group, and preferably has a hydroxyl value generally within the range of 20 to 200 mgKOH / g, particularly 20 to 150 mgKOH / g, from the viewpoints of water dispersibility or compatibility with other components, curability of the coating film formed, etc. The aqueous polyester resin preferably has an acid value generally within the range of 1 to 100 mgKOH / g, particularly 10 to 70 mgKOH / g.

[0148] (3) Ester compounds The resin component (A) used in the present invention may be an ester compound having an alkyl ester group. Examples of the ester compound include the following.

[0149] (3-1) (Compound obtained by addition reaction of a compound having an active methylene group with a vinyl group) A compound having an active methylene group represented by the following general formula (61) undergoes an addition reaction with a vinyl group.

[0150] [ka] (In the formula, R 14 represents an alkyl group having 50 or less carbon atoms. X is OR 14 represents a group or a hydrocarbon group having 5 or less carbon atoms)

[0151] The structure of the alkyl ester group is not particularly limited, but any alkyl ester group having a known ester group, such as a methyl ester group, an ethyl ester group, a benzyl ester group, an n-propyl ester group, an isopropyl ester group, an n-butyl ester group, an isobutyl ester group, or a sec-butyl ester group, can be used.

[0152] Specific examples of such compounds having an active methylene group include malonic acid esters, acetoacetic acid esters, etc. Compounds obtained by adding these compounds to vinyl compounds can be used.

[0153] Compounds having active methylene groups can be added to double bonds by Michael addition reaction. A typical Michael addition reaction using such compounds having active methylene groups is shown in the following formula:

[0154] [ka]

[0155] The compound obtained by such a reaction has a structure represented by the general formula (61), which is a compound having two or more alkyl ester groups, and therefore can be particularly suitably used for the purpose of the present invention. In particular, when (meth)acrylic acid or a derivative thereof is used as the vinyl compound of the above general formula,

[0156] [ka] This results in a reaction with In the above general formula, R 14 represents an alkyl group having 50 or less carbon atoms. R 20 represents hydrogen or a methyl group. R 19 is not particularly limited and can be any functional group depending on the purpose. The ester compound obtained by such a reaction is

[0157] [ka] The molecule has a constitutional unit represented by the following structure.

[0158] In the above-mentioned reaction, by using an acrylic acid derivative having two or more unsaturated bonds as a raw material, it is also possible to obtain an ester compound having two or more structures represented by the above-mentioned general formula (64) in the molecule. That is, having the functional group,

[0159] [ka] In the present invention, a compound having a structure represented by the following general formula can be preferably used. Such a compound is preferred in that it has high transesterification reactivity and has many COOR groups in the molecule, thereby enabling good curing properties to be obtained. In the above general formula, n is most preferably 2 to 12. Furthermore, Y is not particularly limited as long as it has a structure that gives the compound a molecular weight of 3000 or less, and represents a hydrocarbon group which may have any functional group such as a hydroxyl group, an ester group, or an ether group.

[0160] Many compounds having a structure derived from an ester of a compound having an active methylene group are known, but the compound having the above structure is particularly preferred in that the addition reaction between the malonic acid ester and the vinyl group proceeds easily, the synthesis is easy, and the number of ester groups can be adjusted by selecting the starting material, so that the curing performance and the performance of the cured resin can be easily adjusted. Specifically, dimethyl malonate, di-n-butyl malonate, and the like can be preferably used.

[0161] Such compounds can be obtained by carrying out a Michael addition reaction between various (meth)acrylic acid derivatives having one or more unsaturated bonds as raw materials and a compound having an active methylene group. The above-mentioned "(meth)acrylic acid derivatives having one or more unsaturated bonds" are not particularly limited, but examples thereof include the following.

[0162] Examples of (meth)acrylates having one functional group include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, sec-butyl (meth)acrylate, and t-butyl (meth)acrylate.

[0163] Examples of (meth)acrylates having a functionality of 2 include 1,4-butanediol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, Acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, glycerin di(meth)acrylate, dimethylol tricyclodecane di(meth)acrylate (DCP-A), EO adduct diacrylate of bisphenol A (Kyoeisha Chemical Co., Ltd.; Light Acrylate BP-4EA, BP-10EA), PO adduct diacrylate of bisphenol A (Kyoeisha Chemical Co., Ltd.; BP-4PA, BP-10PA, etc.). Among them, PO adduct diacrylate of bisphenol A (Kyoeisha Chemical Co., Ltd.; BP-4PA), dimethylol tricyclodecane di(meth)acrylate (DCP-A), etc. can be preferably used.

[0164] Examples of the (meth)acrylate having three functional groups include trimethylolmethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethylene oxide modified tri(meth)acrylate, trimethylolpropane propylene oxide modified tri(meth)acrylate, pentaerythritol tri(meth)acrylate, glycerin propoxy tri(meth)acrylate, tris(2-(meth)acryloyloxyethyl)isocyanurate, etc. Among them, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, etc. can be preferably used.

[0165] Examples of the (meth)acrylate having 4 functional groups include dipentaerythritol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol ethylene oxide modified tetra(meth)acrylate, pentaerythritol propylene oxide modified tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, etc. Among them, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, etc. can be preferably used.

[0166] Examples of (meth)acrylates having 4 or more functional groups include polyfunctional (meth)acrylates such as pentaerythritol tetra(meth)acrylate, pentaerythritol ethylene oxide-modified tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ditrimethylolpropane penta(meth)acrylate, propionic acid-modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ditrimethylolpropane hexa(meth)acrylate, and caprolactone-modified dipentaerythritol hexa(meth)acrylate.

[0167] Specific examples of the compound corresponding to the above-mentioned compound (3) are shown below.

[0168] [ka] In the formula, R represents an alkyl group having 50 or less carbon atoms.

[0169] The compound (3) is preferably one having three or more alkyl esters in the molecule, which serve as crosslinking points. That is, the more alkyl ester groups in the molecule, the higher the crosslinking density of the cured resin, and therefore the better the hardness of the cured product, which is preferable in that a cured product with excellent physical properties can be obtained. It is more preferable that the number of alkyl esters in the molecule is 5 or more.

[0170] The dissolution or dispersion of such a compound in an aqueous medium can be carried out by diluting it in a water-soluble solvent and adding it, or by emulsifying or dispersing it using an emulsifier. In this case, the compound can be mixed with other components to be used in combination and then emulsified and dispersed with an emulsifier, or the compound alone can be emulsified and dispersed with an emulsifier to prepare a dispersion, which can then be mixed with other components. Equipment used for emulsifying and dispersing includes homomixers, high-pressure homogenizers, dispersing mixers, ribbon mixers, propeller mixers, and high-pressure emulsifiers.

[0171] (3-2) Alkyl esters of polyfunctional carboxylic acids A compound obtained by reacting a polyfunctional carboxylic acid with an alcohol can also be used as the compound having an alkyl ester group of the present invention. Such a reaction can be represented by the following general formula:

[0172] [ka]

[0173] In addition, compounds having an alkyl ester group obtained by carrying out a similar reaction on a carboxylic acid derivative can also be used for the purpose of the present invention.

[0174] Various polyfunctional carboxylic acids are versatile raw materials that are widely and inexpensively provided for many applications, such as polyester raw materials, polyamide raw materials, neutralizing agents, synthetic raw materials, etc. Compounds obtained by alkyl esterifying such polyfunctional carboxylic acids by known methods can also be used in the present invention.

[0175] When such a compound is used as a compound having an alkyl ester group, it can be esterified at low cost by a known method, and a polyvalent ester group can be introduced at a relatively low molecular weight. Furthermore, esterification is preferable in that it improves compatibility with organic solvents and allows for suitable use.

[0176] The polyfunctional carboxylic acid used here is not particularly limited, and for example, one having 50 or less carbon atoms can be used. More specifically, aliphatic polycarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, octadecanedioic acid, citric acid, and butanetetracarboxylic acid; alicyclic polycarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, 3-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, and 1,3,5-cyclohexanetricarboxylic acid; Aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, trimellitic acid, and pyromellitic acid; Fatty acids such as coconut oil fatty acid, cottonseed oil fatty acid, hempseed oil fatty acid, rice bran oil fatty acid, fish oil fatty acid, tall oil fatty acid, soybean oil fatty acid, linseed oil fatty acid, tung oil fatty acid, rapeseed oil fatty acid, castor oil fatty acid, dehydrated castor oil fatty acid, and safflower oil fatty acid; monocarboxylic acids such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, p-tert-butylbenzoic acid, cyclohexanoic acid, and 10-phenyloctadecanoic acid; hydroxycarboxylic acids such as lactic acid, 3-hydroxybutanoic acid, and 3-hydroxy-4-ethoxybenzoic acid; etc. can be mentioned.

[0177] In the present invention, the method for alkyl esterification of the above-mentioned polyfunctional carboxylic acid is not particularly limited, and a known method such as dehydration condensation with an alcohol can be applied. In addition, a method of alkyl esterification of a derivative of a polyfunctional carboxylic acid can also be mentioned.

[0178] The alkyl ester of the polyfunctional carboxylic acid preferably has a molecular weight of 10,000 or less. This is preferable because the molecules are easily mobile and the curing proceeds easily. The molecular weight can also be lower, such as 6,000 or less, 4,000 or less, or 2,000 or less.

[0179] (3-3) Compounds having two or more functional groups represented by general formula (31) Compounds having two or more functional groups represented by the above general formula (31) can also be used in the present invention.

[0180] The functional group represented by the general formula (31) has been described in detail above. Such a functional group is formed by reacting a compound represented by the general formula (32) with a carboxylic acid. Therefore, by reacting various known polycarboxylic acids with the compound represented by the general formula (32) described above, a compound having two or more functional groups represented by the general formula (31) can be obtained. Furthermore, by reacting with a hydroxycarboxylic acid having a hydroxyl group, a compound having a hydroxyl group and the general formula (32) is obtained, which can also be used as a component of a thermosetting resin composition that undergoes a curing reaction by transesterification.

[0181] The above compound is preferably a compound having two or more functional groups when used in the thermosetting resin composition of the present invention, and examples of the compound that can be used include polycarboxylic acids having two or more carboxyl groups, and hydroxycarboxylic acids having a carboxyl group and a hydroxyl group.

[0182] Various polycarboxylic acids are versatile raw materials that are widely and inexpensively available for many applications, such as polyester raw materials, polyamide raw materials, neutralizing agents, synthetic raw materials, etc. Compounds obtained by converting such polycarboxylic acids to the functional group represented by the above general formula (32) by known methods can also be used in the present invention.

[0183] When such a compound is used as a compound having a functional group represented by general formula (32), it can be esterified at low cost by a known method, and a polyvalent ester group can be introduced at a relatively low molecular weight. Furthermore, esterification is preferable in that it improves compatibility with organic solvents and can be used suitably.

[0184] The polycarboxylic acid used here is not particularly limited, and for example, one having 50 or less carbon atoms can be used. More specifically, aliphatic polycarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, octadecanedioic acid, citric acid, and butanetetracarboxylic acid; alicyclic polycarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, 3-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, and 1,3,5-cyclohexanetricarboxylic acid; Aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, trimellitic acid, and pyromellitic acid; Fatty acids such as coconut oil fatty acid, cottonseed oil fatty acid, hempseed oil fatty acid, rice bran oil fatty acid, fish oil fatty acid, tall oil fatty acid, soybean oil fatty acid, linseed oil fatty acid, tung oil fatty acid, rapeseed oil fatty acid, castor oil fatty acid, dehydrated castor oil fatty acid, and safflower oil fatty acid; monocarboxylic acids such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, p-tert-butylbenzoic acid, cyclohexanoic acid, and 10-phenyloctadecanoic acid; hydroxycarboxylic acids such as lactic acid, 3-hydroxybutanoic acid, and 3-hydroxy-4-ethoxybenzoic acid; etc. can be mentioned.

[0185] The compound in which the carboxylic acid group of the polycarboxylic acid is substituted with the structure represented by the general formula (31) preferably has a molecular weight of 10,000 or less. This is preferable in that the molecules are easily mobile and the curing proceeds. The molecular weight can also be lower, such as 6,000 or less, 4,000 or less, or 2,000 or less.

[0186] As an example of such a compound, the general structure of the compound obtained by carrying out the above-mentioned reaction using citric acid as the polycarboxylic acid is shown below.

[0187] [ka]

[0188] (3-4) Compounds having two or more functional groups represented by general formula (41) and / or general formula (42) The compound having a functional group represented by general formula (41) and / or a functional group represented by general formula (42) can be obtained by the production method as described above. Such compounds having two or more functional groups, and compounds having such functional groups and a hydroxyl group, can be suitably used as components of resin compositions in which the curing reaction is an ester exchange reaction.

[0189] The compound having the functional group represented by the general formula (41) and / or the functional group represented by the general formula (42) is used as a curable functional group in the curable resin composition. Therefore, it is preferable that the compound has two or more functional groups. More specifically, the compound may have two or more functional groups represented by the general formula (41) and / or the general formula (42), or may have a hydroxyl group or the like in addition to the functional group represented by the general formula (41) and / or the general formula (42).

[0190] As described above, the functional group represented by the general formula (41) and / or the functional group represented by the general formula (42) can be introduced into various epoxy compounds by carrying out the reaction represented by the general formula (51) or the reaction represented by the general formula (54). Therefore, a compound obtained by subjecting a known epoxy compound to the reaction represented by the above general formula (54) can also be used in the present invention. Epoxy compounds that can be used in such reactions are not particularly limited, but examples thereof include aliphatic polyfunctional liquid epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenyl type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol derivative epoxy resins, novolac type epoxy resins containing a naphthalene skeleton or an alicyclic skeleton, and epoxy resins in which the oxirane ring is a glycidyl ether. The epoxy compound is preferably a compound having two or more epoxy groups in one molecule.

[0191] Furthermore, as described above, an epoxy compound can be obtained by subjecting a carboxylic acid or a derivative thereof to the reaction represented by the general formula (53). Then, by subjecting the epoxy compound to the reaction represented by the above general formula (51) and / or general formula (54), a compound having a functional group represented by general formula (41) and / or a functional group represented by general formula (42) can be obtained. Therefore, by carrying out the above-mentioned reaction on various polycarboxylic acids and hydroxycarboxylic acids, it is possible to obtain compounds having two or more such functional groups, or compounds having such functional groups and a hydroxyl group.

[0192] The polycarboxylic acid that can be used as a raw material for producing a compound having a functional group represented by general formula (41) and / or a functional group represented by general formula (42) by the above reaction is not particularly limited, and for example, one having a carbon number of 50 or less can be used. More specifically, aliphatic polycarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, octadecanedioic acid, citric acid, and butanetetracarboxylic acid; alicyclic polycarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, 3-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, and 1,3,5-cyclohexanetricarboxylic acid; Aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, trimellitic acid, and pyromellitic acid; Examples of fatty acids include coconut oil fatty acid, cottonseed oil fatty acid, hempseed oil fatty acid, rice bran oil fatty acid, fish oil fatty acid, tall oil fatty acid, soybean oil fatty acid, linseed oil fatty acid, tung oil fatty acid, rapeseed oil fatty acid, castor oil fatty acid, dehydrated castor oil fatty acid, and safflower oil fatty acid; and monocarboxylic acids such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, p-tert-butylbenzoic acid, cyclohexanoic acid, and 10-phenyloctadecanoic acid.

[0193] Examples of hydroxycarboxylic acids having a carboxyl group and a hydroxyl group that can be used as a raw material for producing a compound having a functional group represented by general formula (41) and / or a functional group represented by general formula (42) by the above reaction include hydroxycarboxylic acids such as glycolic acid, citric acid, lactic acid, 3-hydroxybutanoic acid, and 3-hydroxy-4-ethoxybenzoic acid; etc. can be mentioned.

[0194] Specific examples of such compounds include compounds having the structures shown below.

[0195] [ka]

[0196] (3-5) Cyanuric acid ester compounds Examples of the ester compound having an alkyl ester group that can be used in the present invention include the cyanuric acid ester compounds exemplified below.

[0197] One of them is an ester compound having an isocyanuric acid ring represented by the following general formula (71).

[0198] [ka] (In the formula, R1 is hydrogen or a structure represented by R2-COOR3. R2 is a hydrocarbon group having 50 or less atoms in its main chain, which may have one or more functional groups selected from the group consisting of an ester group, an ether group, an amide group, and a urethane group in the main chain, and which may have a side chain. R3 is an alkyl group having 50 or less carbon atoms.

[0199] The ester compound represented by the above general formula (71) has two or three alkyl ester groups and can be made to have particularly excellent transesterification reactivity, and is therefore particularly preferred for obtaining a resin composition having a curing initiation temperature of 130°C or less and a gel fraction of 80% or more when cured under the conditions of baking at 150°C for 30 minutes.

[0200] In the monomer represented by the above general formula (71), R3 preferably has a primary or secondary alkyl ester group. The primary or secondary alkyl ester group derived from such a monomer is easily reacted with a hydroxyl group, and therefore the object of the present invention can be sufficiently achieved.

[0201] The alkyl ester group is not particularly limited, and may be one having a known ester group such as a methyl ester group, an ethyl ester group, a benzyl ester group, an n-propyl ester group, an isopropyl ester group, an n-butyl ester group, an isobutyl ester group, or a sec-butyl ester group. The alkyl group preferably has 50 or less carbon atoms. Since the alkyl group is preferably generated as an alcohol during the transesterification reaction and volatilizes, the alkyl group preferably has 20 or less carbon atoms, and more preferably has 10 or less carbon atoms. The boiling point of the alcohol volatilized in the curing reaction is preferably 300° C. or less, and more preferably 200° C. or less.

[0202] The method for producing the ester compound represented by the above general formula (71) is not particularly limited, but one example is a method in which a halogenated carboxylate is reacted with cyanuric acid. This reaction is represented by the following general formula:

[0203] [ka] (In the formula, R3 is an alkyl group having 50 or less carbon atoms. R4 is an alkylene group having 50 or less carbon atoms. X is a halogen element.

[0204] The halogenated carboxylate used in the above reaction may be any known ester, for example, methyl chloroacetate, ethyl chloroacetate, propyl chloroacetate, isopropyl chloroacetate, methyl 2-chloropropionate, ethyl 2-chloropropionate, propyl 2-chloropropionate, isopropyl 2-chloropropionate, methyl 2-chlorobutyrate, ethyl 2-chlorobutyrate, propyl 2-chlorobutyrate, isopropyl 2-chlorobutyrate, methyl bromoacetate, ethyl bromoacetate, propyl bromoacetate, isopropyl bromoacetate, methyl 2-bromopropionate, Examples of the iodoacetate include ethyl 2-bromopropionate, propyl 2-bromopropionate, isopropyl 2-bromopropionate, methyl 2-bromobutyrate, ethyl 2-bromobutyrate, propyl 2-bromobutyrate, isopropyl 2-bromobutyrate, ethyl iodoacetate, propyl iodoacetate, isopropyl iodoacetate, methyl 2-iodopropionate, ethyl 2-iodopropionate, propyl 2-iodopropionate, isopropyl 2-iodopropionate, methyl 2-iodobutanoate, ethyl 2-iodobutanoate, propyl 2-iodobutanoate, and isopropyl 2-iodobutanoate. The above reaction is a well-known general reaction, and the reaction conditions thereof can be general conditions.

[0205] Another method for producing the ester compound represented by the general formula (71) is to react a carboxylic acid having an isocyanuric acid ring with an orthoformate ester, which is represented by the following general formula:

[0206] [ka] (In the formula, R5 is hydrogen or a structure represented by R4-COOH. R4 is an alkylene group having 50 or less carbon atoms. R6 is hydrogen or a structure represented by R4-COOR3.

[0207] Examples of the carboxylic acid having an isocyanuric acid ring used in the above reaction include tris(2-carboxyethyl) isocyanurate and bis(2-carboxyethyl) isocyanurate. Examples of the orthoformate used in the above reaction include methyl orthoformate and ethyl orthoformate. The above reaction is a well-known general reaction, and the reaction conditions thereof can be general conditions.

[0208] Specific examples of the chemical structure of the ester compound having an isocyanuric acid ring represented by the above general formula (71) are shown below. Note that the present invention is not limited to the compounds exemplified below.

[0209] [ka]

[0210] In addition to the above, the cyanuric acid ester compounds usable in the present invention may include, for example, the cyanuric acid ester compounds exemplified below.

[0211] [ka] (In the formula, R 11 is an alkylene group having 50 or less carbon atoms. R 12 is an alkyl group having 50 or less carbon atoms.)

[0212] The ester compound represented by the above general formula (72) can also be made to have particularly excellent transesterification reactivity, and is therefore particularly preferred for obtaining a resin composition having a curing initiation temperature of 130° C. or lower and a gel fraction of 80% or higher when cured under the conditions of baking at 150° C. for 30 minutes.

[0213] The method for producing the ester compound represented by the above general formula (72) is not particularly limited, but for example, a method of reacting cyanuric chloride with a hydroxycarboxylic acid ester can be mentioned. This reaction is represented by the following general formula.

[0214] [ka]

[0215] Examples of the hydroxy acid ester used in the above reaction include methyl glycolate, ethyl glycolate, butyl glycolate, methyl hydroxypropionate, ethyl hydroxypropionate, butyl hydroxypropionate, methyl hydroxybutyrate, ethyl hydroxybutyrate, butyl hydroxybutyrate, methyl lactate, ethyl lactate, and butyl lactate.

[0216] When various cyanuric acid compounds are used in the present invention, they have the advantage that they can give coating films that exhibit excellent film properties, such as high crosslink density, even when cured at low temperatures. When such a compound is used as a compound having an alkyl ester group, it can be esterified inexpensively by a known method, and a polyvalent ester group can be introduced at a relatively low molecular weight.

[0217] (4) Low molecular weight polyol Furthermore, a low molecular weight polyol (specifically, a molecular weight of 2,000 or less) may be used as the compound having at least two hydroxyl groups in the molecule. Examples of low molecular weight polyols include ethylene glycol, propylene glycol, diethylene glycol, trimethylene glycol, tetraethylene glycol, triethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol, 3-methyl-1,2-butanediol, 1,1,1-trimethylolpropane, 2-butyl-2 -ethyl-1,3-propanediol, 1,2-pentanediol, 1,5-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 2,3-dimethyltrimethylene glycol, tetramethylene glycol, 3-methyl-4,3-pentanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,6-hexanediol, 1,5-hexanediol, 1,4-hexanediol, 2,5- Examples of the dihydric alcohols include hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, neopentyl glycol hydroxypivalate, hydrogenated bisphenol A, hydrogenated bisphenol F, and dimethylolpropionic acid; polylactone diols obtained by adding lactone compounds such as ε-caprolactone to the above dihydric alcohols; ester diol compounds such as bis(hydroxyethyl)terephthalate; polyether diol compounds such as alkylene oxide adducts of bisphenol A, polyethylene glycol, polypropylene glycol, and polybutylene glycol; and trihydric or higher alcohols such as glycerin, trimethylolethane, trimethylolpropane, diglycerin, triglycerin, 1,2,6-hexanetriol, pentaerythritol, dipentaerythritol, tris(2-hydroxyethyl)isocyanuric acid, sorbitol, and mannitol.

[0218] Such low molecular weight polyols are known as general-purpose products and are available at low cost. Furthermore, low molecular weight polyols are highly water-soluble and can be suitably used as crosslinking agents when the purpose is curing in an aqueous system.

[0219] The curable resin composition of the present invention is characterized by being curable at low temperatures. In order to obtain a resin composition having such properties, particularly preferred resins are those shown below. It has a structure represented by general formula (12), (31) or (64), and in particular, it is preferred that it has a structure represented by general formula (31).

[0220] The curable composition of the present invention may be used in combination with other crosslinking agents generally used in the fields of paints and adhesives, in addition to the above-mentioned resin components. The crosslinking agents that can be used are not particularly limited, and examples thereof include isocyanate compounds, blocked isocyanate compounds, melamine resins, epoxy resins, and silane compounds. In addition, vinyl ethers, anionic polymerizable monomers, cationic polymerizable monomers, and radical polymerizable monomers may be used in combination. A curing agent for promoting the reaction of these crosslinking agents used in combination may be used in combination.

[0221] The above-mentioned other crosslinking agents are not essential, and even if the curable resin composition of the present invention does not contain them, it is preferable in that good curability can be obtained.

[0222] When the crosslinking agent is a polyisocyanate compound and / or a melamine resin, the blending amount relative to the total amount of the resin component (A) and the crosslinking agent (i.e., (amount of crosslinking agent) / (amount of crosslinking agent+amount of resin component) is preferably 0.01 to 50% by weight. Such a blending amount range is preferable in that a curing reaction by transesterification and a curing reaction by another curing agent occur simultaneously. The lower limit is more preferably 0.01% by weight, and even more preferably 1% by weight, and the upper limit is more preferably 30% by weight, and even more preferably 20% by weight.

[0223] The curable resin composition of the present invention can be suitably used in the fields of curable coating materials, curable adhesives, etc. In particular, it can be used as a room-drying curable resin composition.

[0224] When used as a thermosetting coating material, additives generally used in the coating field may be used in combination with the above-mentioned components, such as leveling agents, defoamers, coloring pigments, extender pigments, luster pigments, pigment dispersants, rheology control agents, UV absorbers, and any combinations thereof.

[0225] When a pigment is used, it is preferable that the total content of the pigment is in the range of 1 to 500% by weight based on 100% by weight of the total solid content of the resin components. The lower limit is more preferably 3% by weight, and even more preferably 5 parts by weight. The upper limit is more preferably 400% by weight, and even more preferably 300% by weight.

[0226] Examples of the color pigment include titanium oxide, zinc oxide, carbon black, molybdenum red, Prussian blue, cobalt blue, azo pigments, phthalocyanine pigments, quinacridone pigments, isoindoline pigments, threne pigments, perylene pigments, dioxazine pigments, diketopyrrolopyrrole pigments, and any combination thereof.

[0227] Examples of the extender pigment include clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, talc, silica, alumina white, etc., with barium sulfate and / or talc being preferred, and barium sulfate being more preferred.

[0228] Examples of the luster pigment include aluminum (including vapor-deposited aluminum), copper, zinc, brass, nickel, aluminum oxide, mica, aluminum oxide coated with titanium oxide or iron oxide, mica coated with titanium oxide or iron oxide, glass flakes, holographic pigments, and any combination thereof. The aluminum pigment includes non-leafing aluminum and leafing aluminum.

[0229] The color pigment is preferably blended in the curable resin composition in a state where it is dispersed in a pigment dispersion resin. The amount of the color pigment may vary depending on the type of pigment, etc., but is generally within a range of preferably about 0.1 to about 300 parts by weight, and more preferably about 1 to about 150 parts by weight, per 100 parts by weight of the solid content of the resin component contained in the pigment dispersion resin.

[0230] The curable coating material may further contain, if desired, coating additives such as organic solvents, thickeners, ultraviolet absorbers, light stabilizers, defoamers, plasticizers, surface conditioners, anti-settling agents, dispersants, color-flux prevention agents, rheology control agents, leveling agents, substrate wetting agents, and slip agents.

[0231] Examples of the thickener include inorganic thickeners such as silicates, metal silicates, montmorillonite, and colloidal alumina; polyacrylic acid thickeners such as copolymers of (meth)acrylic acid and (meth)acrylic acid esters, and sodium polyacrylate; associative thickeners that have a hydrophilic portion and a hydrophobic portion in one molecule and exhibit a thickening effect in an aqueous medium by adsorbing the hydrophobic portion to the surface of a pigment or emulsion particle in a paint, or by associating with each other of the hydrophobic portions; cellulose derivative thickeners such as carboxymethylcellulose, methylcellulose, and hydroxyethylcellulose; casein, sodium caseinate, Examples of thickeners include protein-based thickeners such as ammonium caseinate; alginic acid-based thickeners such as sodium alginate; polyvinyl-based thickeners such as polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl benzyl ether copolymers; polyether-based thickeners such as Pluronic (registered trademark) polyether, polyether dialkyl esters, polyether dialkyl ethers, polyether epoxy modified products, etc.; maleic anhydride copolymer-based thickeners such as partial esters of vinyl methyl ether-maleic anhydride copolymers; polyamide-based thickeners such as polyamide amine salts, etc., as well as any combination thereof.

[0232] The polyacrylic acid thickeners are commercially available, and examples thereof include "ACRYSOLASE-60," "ACRYSOLTT-615," and "ACRYSOLRM-5" (all trade names) manufactured by Rohm and Haas Company, and "SN Thickener 613," "SN Thickener 618," "SN Thickener 630," "SN Thickener 634," and "SN Thickener 636" (all trade names) manufactured by San Nopco Company.

[0233] In addition, the above-mentioned associative thickeners are commercially available. For example, ADEKA's "UH-420", "UH-450", "UH-462", "UH-472", "UH-540", "UH-752", "UH-756VF", "UH-814N" (all trade names), Rohm and Haas's "ACRYSOLRM-8W", "ACRYSOLRM-825", "ACRYSOLRM-2020NPR", "ACRYSOLRM-12W", "ACRYSOLSCT-275" (all trade names), San Nopco's "SN Thickener 612", "SN Thickener 621N", "SN Thickener 625N", "SN Thickener 627N", "SN Thickener 660T" (all trade names), and the like.

[0234] The pigment dispersion resin is preferably an acrylic pigment dispersion resin, more specifically, for example, an acrylic resin obtained by polymerizing a polymerizable unsaturated monomer with a polymerization initiator in the presence of a hydrophilic organic solvent.

[0235] The polymerizable unsaturated monomer may be the compounds exemplified in the synthesis of the resin described above, and may be used in appropriate combination. The pigment dispersion resin is preferably a resin that is soluble or dispersible in water, and specifically, has a hydroxyl value of preferably 10 to 100 mgKOH / g, and more preferably 20 to 70 mgKOH / g, and an acid value of preferably 10 to 80 mgKOH / g, and more preferably 20 to 60 mgKOH / g.

[0236] The curable resin composition of the present invention preferably contains 5 to 70 mass %, more preferably 7 to 61 mass %, of the pigment dispersion resin in terms of solid content, based on the total mass of the solid content of the resin and the pigment dispersion resin. The above range is preferable from the viewpoints of the storage stability of the curable resin composition and the finish, water resistance, medium sanding property, etc., of the colored coating film formed by using the colored coating composition of the present invention.

[0237] The curable resin composition of the present invention can also be made into an aqueous composition. The method of making it aqueous is not particularly limited, and it can be made aqueous by a general method using the above-mentioned components. Even when it is made aqueous, the transesterification reaction can be suitably promoted by using the transesterification catalyst of the present invention.

[0238] The substrate to which the curable resin composition can be applied is not particularly limited, and examples thereof include outer panels of automobile bodies such as passenger cars, trucks, motorcycles, and buses; automobile parts; household electrical appliances such as mobile phones and audio equipment, building materials, furniture, adhesives, and coating agents for films and glass.

[0239] The above-mentioned curable resin composition is expected to be applicable to substrates such as ships, bridges, and other large structures, which are large structures and therefore difficult to heat when forming a coating film. It can also be used favorably for resin coating on products such as plastic products, where the resin cannot be cured by heating, such as by baking, when you want to color them, give them a glossy finish, or give them a luxurious feel.

[0240] The above-mentioned substrate may be the above-mentioned plastic material, or a plastic surface of an automobile part or the like molded from the plastic material, which has been subjected to a surface treatment, a primer coating, or the like, as desired. Also, the substrate may be a combination of the above-mentioned plastic material and the above-mentioned metal material.

[0241] The coating method of the curable resin composition is not particularly limited, and examples thereof include air spray coating, airless spray coating, rotary atomization coating, curtain coat coating, etc., and air spray coating, rotary atomization coating, etc. are preferred. During coating, electrostatic application may be performed as desired. By the coating method, a wet coating film can be formed from the aqueous coating composition.

[0242] The above wet coating film can also be cured at low temperatures of 80 to 140° C., and can be cured by heating for preferably about 10 to about 60 minutes, and more preferably about 15 to about 40 minutes.

[0243] The thermosetting resin composition of the present invention can also be used in a wet-on-wet multilayer coating film formation method. In this case, a method can be mentioned in which a coating material made of the thermosetting resin composition of the present invention is applied, and then another coating composition is applied thereon without curing, and these two coating layers are baked simultaneously to form a multilayer coating film. In addition, in such a coating method, a multilayer coating film having three or more layers may be formed, with at least one layer being formed by the curable resin composition of the present invention.

[0244] When the curable resin composition of the present invention is used to form such a multi-layer coating film, the coating material used in combination may be water-based or solvent-based. Furthermore, the curing system may be a curing system based on the above-mentioned ester exchange reaction, or may be other curing systems such as melamine curing, isocyanate curing, etc.

[0245] When the curable resin composition of the present invention is used in the field of coatings, it is required that the composition has sufficient curing performance, such as smoothness, water resistance, and acid resistance. On the other hand, when used in fields such as adhesives and pressure sensitive adhesives, high curing performance is not required, which is as high as that required for coating materials. The curable resin composition of the present invention can be made to a level that can be used as a coating material, but even compositions that do not reach such a level may be usable in the fields of adhesives and pressure sensitive adhesives.

[0246] A cured film can be obtained by three-dimensionally crosslinking the curable resin composition of the present invention. Such a cured film has sufficient properties to be used as a coating or adhesive. The above cured film also includes a cured film formed by the above-mentioned method for forming a multi-layer coating film. EXAMPLES

[0247] The present invention will be described in more detail below with reference to examples. Note that the present invention is not limited to the following examples. In the text, "parts" refers to parts by weight.

[0248] Synthesis Example 1 A monomer mixture was prepared by dissolving 35 parts of n-butyl methacrylate (Light Ester NB, product of Kyoeisha Chemical Co., Ltd.), 30 parts of methoxycarbonylmethyl methacrylate, 25 parts of 4-hydroxybutyl acrylate, and 10 parts of styrene, and 5 parts of AIBN as an initiator was dissolved in 20 parts of aromatic hydrocarbon (T-SOL100) to prepare an initiator solution. A flask capable of stirring was charged with 80 parts of aromatic hydrocarbon (T-SOL 100), and while nitrogen was sealed in, the monomer solution and the initiator solution were dropped in. The polymerization temperature at this time was set to 100°C. The dropwise addition was carried out for 2 hours, and the mixture was further aged at 100°C for 4 hours to obtain polymer solution A having a weight average molecular weight of 9400 and a dispersity of 1.80.

[0249] Synthesis Example 2 200 parts of n-butyl methacrylate (Kyoeisha Chemical Co., Ltd.: Light Ester NB), 150 parts of methoxycarbonylmethyl methacrylate, 25 parts of 4-hydroxybutyl acrylate, and 125 parts of styrene were used as a monomer mixture, and 15 parts of 4,4'-azobis(4-cyanovaleric acid) (Fujifilm Wako Pure Chemical Industries, Ltd. V-501) as an initiator, 60 parts of Adeka Reasoap SR-3025 (ADEKA Corporation), and 140 parts of ion-exchanged water were added. After emulsification at room temperature for 1 hour using a homomixer, 140 parts of ion-exchanged water was added to prepare a monomer emulsion. 440 parts of ion-exchanged water and 50 parts of the monomer emulsion were placed in a stirrable flask, and the remaining monomer emulsion was dropped while nitrogen was sealed in to carry out polymerization. The polymerization temperature at this time was 75°C. The dropwise addition was carried out for 3 hours, and the mixture was further aged at 75°C for 5 hours to obtain emulsion A.

[0250] Synthesis Example 3 A monomer mixture was prepared by dissolving 40 parts of n-butyl methacrylate (Light Ester NB, Kyoeisha Chemical Co., Ltd.), 50 parts of 4-hydroxybutyl acrylate, and 10 parts of styrene in butyl acetate as an initiator. An initiator solution was prepared by dissolving 5 parts of 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (Perocta O, Nippon Oil & Fats Co., Ltd.) in butyl acetate. A flask capable of stirring was charged with 100 parts of butyl acetate, and the monomer solution and initiator solution were added dropwise while nitrogen was sealed in. The polymerization temperature at this time was set to 100°C. The dropwise addition took 2 hours, and the mixture was further aged at 100°C for 4 hours, yielding a polymer solution B with a weight average molecular weight of 11,000 and a dispersity of 2.2.

[0251] Synthesis Example 4 A monomer mixture was prepared by dissolving 30 parts of n-butyl methacrylate (Light Ester NB, product of Kyoeisha Chemical Co., Ltd.), 30 parts of methoxycarbonylmethyl methacrylate, 25 parts of 4-hydroxybutyl acrylate, 10 parts of styrene, and 5 parts of methacrylic acid in 20 parts of butyl glycol as an initiator. 80 parts of butyl glycol was placed in a stirrable flask, and the monomer solution and the initiator solution were added dropwise while nitrogen was sealed in. The polymerization temperature was set to 100° C. The dropwise addition was carried out over 2 hours, and the mixture was further aged at 100° C. for 4 hours to obtain polymer solution C.

[0252] Synthesis Example 5 40 parts of trimethylolpropane triacrylate, 55 parts of dimethyl malonate, 56 parts of potassium carbonate, 1.5 parts of 18-crown-6 ether, and 95 parts of tetrahydrofuran were mixed and stirred at 50° C. for 3 hours. After the reaction was completed, cyclohexane and water were added and washed with water. The organic layer was neutralized with a saturated aqueous ammonium chloride solution and then washed twice with water. The obtained organic layer was concentrated under reduced pressure to obtain ester compound A.

[0253] Synthesis Example 6 25 parts of tris(2-carboxyethyl)isocyanurate, 100 parts of methanol, 100 parts of trimethyl orthoformate, and 0.8 parts of paratoluenesulfonic acid were added to a stirrable flask and reacted at 80° C. for 5 hours. After the reaction was completed, 200 parts of toluene and 100 parts of water were added and washed, and the organic layer was washed once with 100 parts of 3% sodium bicarbonate water and twice with 100 parts of water. The obtained organic layer was concentrated under reduced pressure to obtain ester compound B.

[0254] In the present examples, the weight average molecular weight and the degree of dispersion are the area ratio and the polystyrene equivalent molecular weight measured by gel permeation chromatography (GPC), respectively. The column used was GPC KF-804L, and the solvent used was tetrahydrofuran.

[0255] Synthesis Example 7 49 parts of 2-methylimidazole and 51 parts of methyl acrylate were mixed and stirred at 60° C. for 2 hours to obtain imidazole compound A through the following reaction. [ka]

[0256] Synthesis Example 8 42 parts of 2-methylimidazole and 58 parts of 2-hydroxyethyl acrylate were mixed and stirred at 60° C. for 2 hours to obtain imidazole compound B through the following reaction. [ka]

[0257] Examples 1 to 12, Comparative Examples 1 to 4 The components shown in Table 1 were mixed, and a 400 μm wet coating was formed on a PET film using an applicator, and then dried for 30 minutes at the temperature shown in the table. After that, the mixture was left to stand at 22°C for 72 hours, after which gel fraction measurement, pencil hardness, and rigid pendulum test were performed using the adjusted solution. In Table 1, DABCO (registered trademark) is triethylenediamine. Each evaluation was carried out as follows, and the results are shown in Tables 1 and 2.

[0258] The gel fraction was measured as the remaining weight % of the film by dissolving the film obtained in each example in refluxing acetone for 30 minutes using a Soxhlet. A gel fraction of 0 to 40% was rated as x since it was considered unsuitable for practical use. A gel fraction of 40 to 60% was rated as fair, as it was deemed that a certain degree of hardening was observed. A gel fraction of 60 to 80% was deemed suitable for practical use and was marked as "good." A gel fraction of 80 to 100% was rated as excellent.

[0259] The pencil hardness was measured in accordance with JIS K5600-5-4 with a load of 750 g on the cured coating film, and the result of no scratches was recorded in 4 or more out of 5 tests.

[0260] The rigid pendulum test was carried out using an A&D rigid pendulum tester (model number RPT-3000W) at a temperature rise rate of 3°C / min. Pendulum: FRB-100 Film thickness (WET): 100μm

[0261] [Table 1]

[0262] [Table 2]

[0263] The results in Table 1 show that by using the transesterification catalyst (B) according to the present invention, a curable resin composition exhibiting a low-temperature curing reaction can be obtained. [Industrial Applicability]

[0264] The curable resin composition of the present invention is a curable resin composition that can be suitably used in fields requiring curing at low temperatures.

Claims

1. -COOR (R is an alkyl group having 50 or less carbon atoms), a resin component (A) having a hydroxyl group, and an ester exchange catalyst (B). Contains A curable resin composition, wherein the transesterification catalyst (B) contains a zinc-containing compound and an imidazole compound.

2. 2. The curable resin composition according to claim 1, wherein the zinc compound is at least one zinc compound selected from the group consisting of zinc acetate, zinc octylate, zinc naphthenate, zinc gluconate, zinc acrylate, zinc acetylacetonate, zinc trifluoromethanesulfonate, and zinc oxide.

3. The curable resin composition according to claim 1 or 2, wherein the imidazole compound is represented by the following general formula: 【Chemistry 1】 (In the formula, R １ R is an alkyl group, an alkenyl group, or an aromatic substituent having 10 or less carbon atoms, which may have a branched or cyclic structure, and may have at least one group selected from the group consisting of a hydroxyl group, an amino group, a carbonyl group, a cyano group, an ester group, an amide group, an ether group, and a nitro group. ２ ~R ４ are each independently a hydrogen atom, an alkyl group having 10 or less carbon atoms, an alkenyl group, or an aromatic substituent, and may have at least one selected from the group consisting of a hydroxyl group, an amino group, a carbonyl group, a cyano group, an ester group, an amide group, an ether group, and a nitro group.

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