JP2003171609A - Thermosetting coating composition and coating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosetting coating composition which can form a coating film excellent in the balance between the film hardness and the processability, retorting resistance, and yellowing resistance, gives a coating material excellent in storage stability, and is useful particularly for a coating material for a metal, and a coating material obtained by using it. <P>SOLUTION: The thermosetting coating composition contains an acrylic copolymer (A) obtained by copolymerizing an α,β-monoethylenically unsaturated carboxylic acid (a), a hydroxylated (meth)acrylic ester (b) represented by general formula (I) and/or a carboxylated (meth)acrylic ester (c) represented by general formula (II), a metal-containing polymerizable monomer (d), and a vinyl monomer (e) copolymerizable with the component (a), component (b) and/or component (c), and component (d), and having an acid value of 15-150 mgKOH/g and a weight-average molecular weight of 3,000 to 80,000, and an epoxy compound (B) having two or more glycidyl groups in the molecule. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention can form a coating film having excellent balance between coating film hardness and processability, retort resistance and yellowing resistance, and further has excellent storage stability when used as a paint. The present invention relates to a thermosetting coating composition and a paint using the same. In particular, it relates to a thermosetting coating composition that can be suitably used as a metal coating material and a coating material using the same.

[0002]

2. Description of the Related Art Usually, a metal can used as a spray can for cosmetics and insecticides is coated on the outer surface. The coating material used for such a metal can is required to have rust-preventing property and design property, and is also required to have workability (flexibility) in the can manufacturing process and the canning manufacturing process. Also, canned coffee, canned juice,
Paints used for beverage cans such as canned beer and food cans such as processed fish cans must withstand the retort process during food sterilization. As described above, many high performances are required for the metal coating used on the outer surface of the can.

For the purpose of satisfying such strict performance requirements, various metals such as acrylic resin / amino resin type paint, polyester resin / amino resin type paint, epoxy resin / amino resin type paint, etc. have been used so far. Paints have been proposed. Acrylic resin / amino resin-based paints have the characteristic that the coating film has good retort resistance, and polyester resin / amino resin-based paints and epoxy resin / amino resin-based paints have good workability. It has the feature of being.

However, the acrylic resin / amino resin type coating material has a drawback that the workability becomes low when trying to increase the hardness of the coating film, and thus the polyester resin / amino resin type coating material and the epoxy resin / amino resin type coating material. Had a defect that the retort resistance of the coating film was low. In addition, the coating material using the amino resin also has a problem that volatile low molecular weight substances (fumes) are generated during baking, which fall after being deposited in the baking furnace and contaminate the coating film (humming). .

Acrylic resins / metal resins having good balance between coating hardness and workability and good retort resistance
Epoxy resin-based paints are known. This acrylic resin / epoxy resin-based paint has few problems of fuming. However, acrylic resin / epoxy resin-based paints require the use of hardening accelerators such as tertiary amines and quaternary ammonium compounds, and the use of such hardening accelerators reduces the storage stability of the paint. Or the cured coating film turns yellow.

On the other hand, it has been proposed to use a metal chelate as a curing accelerator as a means for improving the storage stability of the paint. For example, Japanese Unexamined Patent Publication (Kokai) No. 52-115894 discloses the use of an acrylic / epoxy thermosetting resin composition containing a metal chelate compound such as an acetylacetone transition metal salt that releases a metal at the curing temperature of the resin. .

[0007]

However, when an acrylic / epoxy thermosetting resin composition containing such a metal chelate compound as a curing accelerator is applied to a metal, the storage stability is good. However, there is a problem that the balance between hardness and workability of the obtained coating film and the retort resistance are deteriorated. Therefore, it has been difficult to apply such a resin composition to a metal coating material. As a solution to such a problem, a thermosetting coating composition containing a carboxyl group-containing acrylic copolymer having a specific acid value and molecular weight, a specific glycidyl group-containing epoxy compound, and an organic metal salt The object is JP-A-10-212
No. 450 is disclosed. However, the thermosetting coating composition containing a low molecular weight organometallic salt as a curing accelerator is still insufficient in retort resistance and storage stability.

The present invention has been made to solve the above-mentioned problems, and it is possible to form a coating film excellent in balance between coating film hardness and processability, retort resistance and yellowing resistance, and to obtain a coating material. It is intended to provide a thermosetting coating composition which has excellent storage stability and is particularly useful as a coating material for metals, and a coating material using the same.

[0009]

The inventors of the present invention have made extensive studies to solve the above problems, and as a result, have a metal-containing polymerizable monomer as a constituent component and a specific hydroxyl group-containing (meth) acryl. An acrylic / epoxy thermosetting resin composition containing an acrylic copolymer having a specific acid value and a weight average molecular weight obtained by copolymerizing an acid ester and / or a specific carboxyl group-containing (meth) acrylic acid ester is described above. The present invention has been completed by solving the problems and finding that it can be suitably used as a metal coating material.

That is, the thermosetting coating composition of the present invention comprises an α, β-monoethylenically unsaturated carboxylic acid (a)
2 to 30% by mass (also referred to as component (a)), a hydroxyl group-containing (meth) acrylic acid ester represented by the following general formula (I) (b) (also referred to as component (b)) and / or the following general formula ( II) carboxyl group-containing (meth) acrylic acid ester (c) (also referred to as component (c)) 3 to 30% by mass, metal-containing polymerizable monomer (d) (also referred to as component (d)) 0.1 to 10% by mass, a vinyl monomer (e) copolymerizable with these (a) component, (b) component and / or (c) component, (d) component (hereinafter, also referred to as (e) component) Note 3
It is obtained by copolymerizing 0 to 94.9% by mass and has an acid value of 15
~ 150 mg KOH / g, with a weight average molecular weight of 30
An acrylic copolymer (A) (also referred to as a component (A)) having a range of from 0 to 80,000, and an epoxy compound (B) having two or more glycidyl groups in the molecule (also referred to as a component (B)) Is contained, and the component (A) is 50 to 95 parts by mass in a total of 100 parts by mass of the component (A) and the component (B).

[0011]

[Chemical 5] (In the formula, R ¹ represents a hydrogen atom or a methyl group, p represents an integer of 2 to 8, q represents an integer of 2 to 5, and m represents an integer of 1 to 10.)

[0012]

[Chemical 6] (In the formula, R ¹ is a hydrogen atom or a methyl group, r is an integer of 2 to 8, s is an integer of 2 to 5, and n is an integer of 1 to 10,
R ² represents a hydrocarbon substituent having 1 to 8 carbon atoms)

Further, the metal-containing polymerizable monomer (d)
Is preferably a metal-containing polymerizable monomer (d1) represented by the general formula (III). (In the formula, R ¹ represents a hydrogen atom or a methyl group, M represents Mg, Zn or Ca, and R ³ represents an organic acid residue.)

[0014]

[Chemical 7]

Further, the metal-containing polymerizable monomer (d)
Is a metal-containing polymerizable monomer (d having two unsaturated groups)
2) is desirable. The metal-containing polymerizable monomer (d) is the metal-containing polymerizable monomer (d1) represented by the general formula (III) and the metal-containing polymerizable monomer having two unsaturated groups. It is preferably a mixture with the body (d2). Further, the coating material of the present invention is characterized by containing the thermosetting coating composition of the present invention.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The acrylic copolymer (A) in the present invention is
Represented by α, β-monoethylenically unsaturated carboxylic acid (a), a hydroxyl group-containing (meth) acrylic acid ester (b) represented by the following general formula (I) and / or the following general formula (II) Copolymerizable with carboxyl group-containing (meth) acrylic acid ester (c), metal-containing polymerizable monomer (d), component (a), component (b), component (c), and component (d) It is obtained by copolymerizing the vinyl monomer (d) with a specific ratio.

[0017]

[Chemical 8]

[0018]

[Chemical 9]

The α, β-monoethylenically unsaturated carboxylic acid (a) used as the component (A) is other than the carboxyl group-containing (meth) acrylic acid ester (c) represented by the general formula (II). Of α, β-monoethylenically unsaturated carboxylic acid, which imparts hardness and retort resistance to the resulting coating film. Examples of the α, β-monoethylenically unsaturated carboxylic acid (a) include acrylic acid, methacrylic acid, crotonic acid, vinylbenzoic acid, fumaric acid, fumaric acid monomethyl ester, fumaric acid monobutyl ester, maleic acid, and maleic acid. Examples thereof include acid monomethyl ester, maleic acid monobutyl ester, itaconic acid, itaconic acid monomethyl ester, itaconic acid monobutyl ester, itaconic anhydride, maleic anhydride, and citraconic acid anhydride. These can be used alone or in combination of two or more. Among these, acrylic acid, methacrylic acid, and itaconic acid are particularly preferable.

The ratio of the component (a) is based on all monomers.
It is in the range of 2 to 30 mass%. When the proportion of the component (a) is 2% by mass or more, the cross-linking density of the obtained cured coating film is in an appropriate range, and the hardness, solvent resistance, retort resistance, etc. of the coating film are good. When the ratio of the component (a) is 30% by mass or less, the obtained cured coating film has appropriate flexibility and the storage stability of the coating material becomes good. The ratio of the component (a) is more preferably 4 to 23% by mass, and further preferably 6 to 15% by mass.

The hydroxyl group-containing (meth) acrylic acid ester (b) and / or the carboxyl group-containing (meth) acrylic acid ester (c) used as the constituent component of the component (A) together with the component (a) are as follows: It is represented by the general formula (I) and the general formula (II). General formula (I)
In, R ¹ is a hydrogen atom or a methyl group, and p is 2-8.
, Q is an integer of 2-5, m is an integer of 1-10, and in the general formula (II), R ¹ is a hydrogen atom or a methyl group, r is an integer of 2-8, and s is 2 5 is an integer, n is an integer of 1 to 10, and R ² is a hydrocarbon substituent having 1 to 8 carbon atoms. Use of this component imparts flexibility to the cured coating film and improves processability. Further, the compatibility of the component (A) and the component (B) is imparted, and the gloss of the cured coating film obtained when the color pigment is used, and the transparency of the cured coating film obtained when the color pigment is not used are improved. Each will improve.

[0022]

[Chemical 10]

[0023]

[Chemical 11]

Specific examples of the compound represented by the above general formula (I) include, for example, 1 mol adduct of γ-butyrolactone of 2-hydroxyethyl (meth) acrylate, 2 mol adduct, 3 mol adduct, and 4 mol. Molar adduct, 5 mol adduct or 2
Ε-caprolactone of hydroxyethyl (meth) acrylate 1 mol adduct, 2 mol adduct, 3 mol adduct, 4
Examples thereof include ring-opening adducts of organic lactones with hydroxyl group-containing (meth) acrylates such as mol adducts and 5 mol adducts. These compounds can be synthesized by a known addition reaction utilizing a transition metal. These can be used alone or in combination of two or more kinds. Among them, ε-caprolactone adduct of 2-hydroxyethyl (meth) acrylate (trade name; Praxel FM-1 to F-F
M-5, FA-1 to FA-5, Daicel Chemical Industries, Ltd.
Manufactured) is particularly preferable.

The compound represented by the general formula (II) is ω-carboxypolycaprolactone mono (meth) acrylate, and specific examples thereof include γ-butyrolactone 1 of 2-hydroxyethyl (meth) acrylate. A monosuccinate of a mole addition, a monosuccinate of a 2 mole addition thereof, a monosuccinate of a 3 mole addition thereof,
Same as above, 4 mol addition monosuccinate, same as 5 mol addition monosuccinate, 2-hydroxyethyl (meth) acrylate γ-butyrolactone 1 mol addition monophthalate, same 2 mol addition monophthalate, Monophthalate of 3 mole adduct, monophthalate of 4 mole adduct, monophthalate of 5 mole adduct, monosuccinate of 1 mole adduct of 2-hydroxyethyl (meth) acrylate ε-caprolactone, 2 Mole adduct monosuccinate, same 3 mole adduct monosuccinate, same 4
Molar adduct monosuccinate, 5 mol adduct monosuccinate, 2-hydroxyethyl (meth) acrylate ε-caprolactone 1 mol adduct monophthalate, 2 mol adduct monophthalate, 3 mol Monophthalate of adduct, Monophthalate of 4 mol adduct,
Hydroxyl group such as monophthalate of the same 5 mol addition (meta)
Examples of the lactone-modified (meth) acrylic acid ester containing a carboxy group obtained by esterification reaction of a polybasic acid such as (anhydrous) succinic acid or (anhydrous) phthalic acid with a ring-opening addition product of an organic lactone to an acrylate. it can. These can be used alone or in combination of two or more kinds. Among them, ε-caprolactone adduct of 2-hydroxyethyl (meth) acrylate (trade name; Praxel FM-1 to F-F
M-5, FA-1 to FA-5, Daicel Chemical Industries, Ltd.
Particularly preferred are polybasic acid esters.

The proportion of the component (b) and / or the component (c) is in the range of 3 to 30% by mass with respect to the total amount of the monomers. When the proportion of the component (b) and / or the component (c) is 3% by mass or more, the resulting cured coating film has suitable flexibility,
It is in the range of good compatibility with the epoxy resin, and the processability, adhesion, gloss and transparency of the coating film are improved. (B)
When the ratio of the component and / or the component (c) is 30% by mass or less, the obtained cured coating film has an appropriate crosslink density, and the hardness and retort resistance of the coating film are good. The ratio of the component (b) and / or the component (c) is more preferably 5 to 2
It is in the range of 5% by mass, and more preferably in the range of 7 to 20% by mass.

The metal-containing polymerizable monomer (d) used as a constituent of the component (A) together with the components (a), (b) and / or (c) is contained in the cured coating film obtained. , While providing adhesion to the metal base,
It is used as a curing accelerator for the components (A) and (B). In addition, since the acrylic copolymer (A) contains the metal-containing polymerizable monomer (d), it is not necessary to use a curing accelerator such as a tertiary amine or a quaternary ammonium salt, and thus a cured coating is obtained. The yellowing resistance of the film is improved.

The ratio of the component (d) is based on all monomers.
It is in the range of 0.1 to 10 mass%. When the ratio of the component (d) is 0.1% by mass or more, the crosslinked density of the obtained cured coating film is in an appropriate range and the hardness, solvent resistance and retort resistance are good. When the ratio of the component (d) is 10% by mass or less, the obtained cured coating film has appropriate flexibility, processability,
The storage stability of the paint becomes good. The ratio of component (d) is
The range is more preferably 0.5 to 7% by mass, and further preferably 1 to 5% by mass.

The metal-containing polymerizable monomer (d) is preferably composed of the metal-containing polymerizable monomer (d1) and / or (d2). Metal-containing polymerizable monomer (d
1) is represented by the following general formula (III). In the following general formula (III), R ¹ represents a hydrogen atom or a methyl group, M represents a metal such as magnesium (Mg), zinc (Zn) or calcium (Ca), and R ³ represents an organic acid residue.

[0030]

[Chemical 12]

As the organic acid residue, monochloroacetic acid, monofluoroacetic acid, propionic acid, octylic acid, versatic acid, oleic acid, isostearic acid, palmitic acid, cresothic acid, α-naphthoic acid, β-naphthoic acid,
Benzoic acid, 2,4,5-trichlorophenoxyacetic acid, 2,
Examples thereof include those derived from monovalent organic acids such as 4-dichlorophenoxyacetic acid, quinolinecarboxylic acid, nitrobenzoic acid, nitronaphthalenecarboxylic acid and puruvic acid.
Among these organic acid residues, fatty acid-based ones are particularly preferable for the acrylic copolymer (A) in the present invention, whereby a coating film free from cracks and peeling can be maintained for a long period of time.

Specific examples of the compound represented by the general formula (III) include, for example, monochloromagnesium acetate (meth) acrylate ((meth) acrylate means acrylate or methacrylate. The same applies hereinafter), monochloro Zinc acetate (meth) acrylate, monochloroacetic acid calcium (meth) acrylate, magnesium monofluoroacetate (meth) acrylate, zinc monofluoroacetate (meth) acrylate, calcium monofluoroacetate (meth) acrylate, magnesium propionate (meth) acrylate, Zinc propionate (meth) acrylate, calcium propionate (meth) acrylate, magnesium octylate (meth) acrylate, zinc octylate (meth) acrylate, calcium octylate (meth) a Relate, magnesium versatate (meth) acrylate, zinc versatate (meth) acrylate, calcium versatate (meth) acrylate, magnesium oleate (meth) acrylate, zinc oleate (meth) acrylate, calcium oleate (meth) acrylate, Magnesium isostearate (meth) acrylate, zinc isostearate (meth) acrylate, calcium isostearate (meth) acrylate,

Magnesium palmitate (meth) acrylate, zinc palmitate (meth) acrylate, calcium palmitate (meth) acrylate, magnesium crethotiate (meth) acrylate, zinc crethotiate (meth) acrylate, calcium crethotiate (meth) acrylate , Α-naphthoate magnesium (meth) acrylate, α-naphthoate zinc (meth) acrylate, α-naphthoate calcium (meth) acrylate, β-naphthoate magnesium (meth) acrylate, β-naphthoate zinc (meth) acrylate , Β-calcium naphthoate (meth) acrylate, magnesium benzoate (meth) acrylate, zinc benzoate (meth) acrylate, calcium benzoate (meth) acrylate, 2,4,5-trichloro Phenoxyacetic acid magnesium (meth) acrylate, 2,4,5-trichlorophenoxyacetic acid zinc (meth) acrylate, 2,4,5-trichlorophenoxyacetic acid calcium (meth) acrylate, 2,4-dichlorophenoxyacetic acid magnesium (meth) acrylate 2,4-dichlorophenoxyacetic acid zinc (meth) acrylate, 2,4-dichlorophenoxyacetic acid calcium (meth) acrylate,

Magnesium quinolinecarboxylate (meth)
Acrylate, zinc quinolinecarboxylate (meth) acrylate, calcium quinolinecarboxylate (meth) acrylate, magnesium nitrobenzoate (meth) acrylate, zinc nitrobenzoate (meth) acrylate, calcium nitrobenzoate (meth) acrylate, nitronaphthalenecarboxylic Acid magnesium (meth) acrylate, zinc nitronaphthalenecarboxylate (meth) acrylate, calcium nitronaphthalenecarboxylate (meth)
Examples thereof include acrylate, magnesium (meth) acrylate purbate, zinc (meth) acrylate purbate, calcium (meth) acrylate purbate and the like.
The metal-containing polymerizable monomer (d1) may be one kind or two kinds.
One or more species can be appropriately selected and used as necessary. Among these, in terms of yellowing resistance and retort resistance,
Zinc-containing polymerizable monomers are preferred.

Among the metal-containing polymerizable monomers (d), the metal
The containing polymerizable monomer (d2) has two unsaturated groups
A metal-containing polymerizable monomer, such as diacrylic acid
Gnesium [(CH₂= CHCOO)₂Mg], dimethac
Magnesium phosphate [(CH ₂= C (CH₃) COO)₂
Mg], zinc diacrylate [(CH₂= CHCOO)₂Z
n], zinc dimethacrylate [(CH₂= C (CH₃) CO
O)₂Zn], calcium diacrylate [(CH₂= CH
COO)₂Ca], calcium dimethacrylate [(CH₂
= C (CH₃) COO)₂Ca] and so on
It These metal-containing polymerizable monomers (d2) are one kind or
Can be used by appropriately selecting two or more kinds as necessary.
Wear. Among these, yellowing resistance and retort resistance
Therefore, zinc di (meth) acrylate is preferable ((
Ta) Acrylic means acrylic or methacrylic
means. same as below).

Further, as the metal-containing polymerizable monomer (d), the metal-containing polymerizable monomer (d1) represented by the following general formula (III) and the metal-containing polymerizable monomer having two unsaturated groups are used. It is also possible to use together with the monomer (d2). In this case, the same type of metal is preferable from the viewpoint of compatibility between the metal-containing polymerizable monomers, and a combination of zinc di (meth) acrylate and a fatty acid zinc (meth) acrylate is particularly preferable.

[0037]

[Chemical 13]

The vinyl monomer (e) used as a constituent of the component (A) together with the components (a), (b) and / or (c), and (d) is obtained by curing. It is appropriately selected and used for imparting excellent coating performance to the coating.

As the vinyl monomer (e), for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate,
sec-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, Phenyl (meth) acrylate, benzyl (meth) acrylate and other hydrocarbon substituent-containing (meth) acrylic acid ester monomers; styrene, α-methylstyrene, vinyltoluene and other styrene derivatives; acrylonitrile, methacrylonitrile, etc. Polymerizable unsaturated nitriles; acrylamide monomers such as N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide;

2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4
-Hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate or 2-hydroxypropyl (meth) acrylate ring-opened addition product of ethylene oxide or propylene oxide, 2-hydroxyethyl (meth) acrylate Or a ring-opening addition product of tetrahydrofuran to 2-hydroxypropyl (meth) acrylate, a hydroxyl group-containing (meth) such as a dimer or trimer of 2-hydroxyethyl (meth) acrylate or 2-hydroxypropyl (meth) acrylate Acrylic ester monomers; vinyl esters such as vinyl acetate; epoxy group-containing monomers such as glycidyl (meth) acrylate, (meth) acrylglycidyl ether; dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) a Basic monomers such as relations are exemplified. These may be used alone or in combination of two or more. Among these, (meth) acrylic acid ester monomers and styrene are preferable in terms of coating film hardness, processability, yellowing resistance, and retort resistance.

The ratio of the component (e) is based on all monomers.
It is in the range of 30 to 94.9% by mass. When the ratio of the component (e) is 30% by mass or more, the obtained cured coating film has appropriate flexibility and good processability, and the storage stability of the coating material is good. When the ratio of the component (e) is 94.9% by mass or less, the obtained cured coating film has an appropriate crosslinking density, and the coating film has good hardness, solvent resistance, retort resistance and the like.
The ratio of the component (e) is more preferably 45 to 90.5% by mass, further preferably 60 to 86% by mass.

Acrylic copolymer (A) in the present invention
The acid value of should be in the range of 15 to 150 mg KOH / g. When the acid value is 15 mgKOH / g or more, the crosslink density of the obtained cured coating film is in an appropriate range, the hardness of the coating film,
Good solvent resistance, retort resistance, etc. Acid value is 150
When it is less than mgKOH / g, the obtained cured coating film has appropriate flexibility and thus has good processability and good storage stability of the coating material. Acrylic copolymer (A)
The acid value of is more preferably 30 to 120 mgKOH /
g, more preferably 40 to 100 mgKOH / g.

Further, the thermosetting coating composition of the present invention is
In particular, for use as a metal coating material, the acrylic copolymer (A) has a weight average molecular weight of 3,000 to 8
It must be in the range of 0000. When the weight average molecular weight of the component (A) is 3000 or more, the coating film obtained has good adhesion, processability, solvent resistance, and retort resistance. When the weight average molecular weight of the component (A) is 80,000 or less, the viscosity of the thermosetting coating composition of the present invention is in an appropriate range, the coating solid content is appropriately maintained, and the appearance of the coating film is good. .
The weight average molecular weight of the component (A) is more preferably 500.
It is in the range of 0 to 50,000.

Acrylic copolymer (A) in the present invention
Is used in the range of 50 to 95 parts by mass in the total 100 parts by mass of the component (A) and the component (B) of the thermosetting coating composition of the present invention. When the amount of the component (A) is 50 parts by mass or more, the resulting coating film has good balance between hardness and workability, retort resistance and the like. When the amount of the component (A) is 95 parts by mass or less, the crosslink density of the obtained cured coating film is in an appropriate range,
Good adhesion, solvent resistance, etc. The component (A) is more preferably in the range of 60 to 90 parts by mass.

Acrylic copolymer (A) in the present invention
Examples of the polymerization method include known polymerization methods such as a solution polymerization method, a bulk polymerization method, and an emulsion polymerization method. Generally, the solution polymerization method is preferable. In the case of the solution polymerization method, the mixture of each of the above monomers is copolymerized in the presence of an organic solvent and a polymerization initiator.

As the organic solvent, isopropyl alcohol, n-butanol, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, ethylene Glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol monobutyl ether acetate, toluene, xylene, "Solvesso # 10" manufactured by Exxon Chemical Co.
0 "," Solvesso # 150 "," Supersol # 1500 "," Supersol # 180 "manufactured by Nisseki Mitsubishi Corp.
0 "," Swasol # 1000 "manufactured by Maruzen Petrochemical Co.,
A commonly used organic solvent such as "Swazol # 1500", methyl ethyl ketone, methyl isobutyl ketone, or cyclohexanone can be used. Among these, it is preferable to use an alcohol-based organic solvent such as n-butanol or ethylene glycol monobutyl ether or a glycol-based organic solvent in combination in view of the solubility of the metal-containing polymerizable monomer (d).

As the polymerization initiator, a commonly used polymerization initiator such as azobisisobutyronitrile, benzoyl peroxide, cumene hydroperoxide, t-butyl peroctoate can be used. Furthermore, if necessary, a chain transfer agent such as 2-mercaptoethanol, n-octylmercaptan, n-dodecylmercaptan, α-methylstyrene dimer or the like can be used.

The epoxy compound (B) having two or more glycidyl groups in the molecule used in the present invention imparts hardness, retort resistance, solvent resistance and the like to the obtained coating film.

In the present invention, the epoxy compound (B) having two or more glycidyl groups in the molecule preferably has an epoxy equivalent of 150 to 3,000. When the epoxy equivalent is 150 or more, the resulting coating film has good solvent resistance, retort resistance, and storage stability of the coating material.
When the epoxy equivalent is 3,000 or less, the viscosity of the thermosetting coating composition of the present invention is in an appropriate range, the solid content of the coating material is appropriately maintained, and the appearance of the coating film is good. The epoxy equivalent is more preferably in the range of 150 to 1500.

In the present invention, the epoxy compound (B) having two or more glycidyl groups in the molecule is a bisphenol A type or bisphenol F type epoxy resin in terms of coating film hardness and retort resistance. Is particularly preferable. For example, "Epicoat 828", "Epicoat 1001", "Epicoat 1004", "Epicoat 1007" of Yuka Shell Epoxy Co., Ltd., Toto Kasei Co., Ltd.
"YD-011", "YD-014", "YDF-2"
"001", "YDF-2004", "Epiclon 1050", "Epiclon 40" from Dainippon Ink and Chemicals, Inc.
50 "and the like. These may be used alone or in combination of two or more.

The epoxy compound (B) having two or more glycidyl groups in the molecule in the present invention is used within a range of 5 to 50 parts by mass in the total 100 parts by mass of the components (A) and (B). To be When the amount of the component (B) is 5 parts by mass or more, the resulting cured coating film has a crosslinking density in an appropriate range,
Good hardness, solvent resistance, retort resistance, etc. (B)
When the amount of the component is 50 parts by mass or less, the balance between hardness and workability of the obtained coating film, retort resistance and the like are good. The component (B) is more preferably in the range of 10 to 40 parts by mass.

The method for producing the thermosetting coating composition of the present invention is not particularly limited, but for example, an epoxy compound (B) having two or more glycidyl groups in the molecule.
Is dissolved in an organic solvent, and the components (a), (b) and / or (c), which are the monomer components of the acrylic copolymer (A), (d), and (e) are dissolved therein. The mixture of components), a polymerization initiator, a chain transfer agent, etc. may be added dropwise for polymerization. Further, the component (B) may be added at the end of the polymerization of the component (A). Further, the component (A) and the component (B) may be mixed when the paint is blended.

The coating composition of the present invention is a coating of the thermosetting coating composition of the present invention, and usually has a solid content of 40 to 7
It is used in the range of 0% by mass. Further, when the thermosetting coating composition of the present invention is made into a paint, pigments such as titanium oxide, carbon black, aluminum paste, talc, calcium carbonate; polyester resin, acrylic resin, epoxy resin, amino resin, alkyd resin , Resins such as fibrin resin; additives such as surface modifiers, defoamers, lubricants, antioxidants, pigment settling inhibitors, thixotropic agents, metal compounds such as acetylacetone metal salts, organic acid metal salts, etc. It can be used as needed.

Examples of the method for applying the coating material of the present invention include, but are not limited to, spray coating method, roller coating method, bar coating method, air knife method, casting method, brush coating method and dipping method. Moreover, after applying the coating composition of the present invention, it is usually in the temperature range of 160 to 280 ° C. for 10 seconds to 10 seconds.
A coating film can be formed by heating for a minute.

[0055]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In addition, "%" and "part" in the examples are
Unless otherwise specified, it is based on mass.

<Synthesis of Acrylic Polymers P-1 to P-14> A container equipped with a stirrer, a temperature controller, a cooling pipe, and a nitrogen introducing pipe was purged with nitrogen, and then the solvents shown in Tables 1 and 2 were used. Was added and heated to 100 ° C. with stirring. Then, the mixture of the monomer and the polymerization initiator having the compositions shown in Tables 1 and 2 was added dropwise over 4 hours. One hour after the completion of the dropping, 0.2 part of azobisisobutyronitrile was added, and the temperature was kept for another 2 hours to increase the conversion rate to a resin, and acrylic copolymers P1 to P14 were synthesized.

[0057]

[Table 1]

[0058]

[Table 2]

* 1) Praxel FM-1: 2-hydroxyethyl (meth) acrylate ε-caprolactone adduct (hydroxyl value 230 mgKOH / g); Daicel Chemical Industries Ltd. * 2) Praxel FM-3: 2- Ε-caprolactone adduct of hydroxyethyl (meth) acrylate (hydroxyl value 119 mgKOH / g); Daicel Chemical Industries Ltd. * 3) Praxel FM-1A: 2-hydroxyethyl
Esterification reaction product of ε-caprolactone adduct of (meth) acrylate and polybasic acid (acid value 143 mgKOH /
g); manufactured by Daicel Chemical Industries, Ltd. * 4) Solvesso # 150: aromatic hydrocarbon; manufactured by Exxon Chemical Co., Ltd. * 5) Weight average molecular weight: measured by gel permeation chromatography and based on polystyrene Indicates a value.

<Preparation of Resin Compositions A-1 to A-21> The thermosetting coating composition (A-1) having the composition shown in Tables 3 and 4 was used.
~ A-21) was obtained.

[0061]

[Table 3]

[0062]

[Table 4]

* 1) Epicoat # 828: Epoxy resin; Yuka Shell Epoxy Co., Ltd., epoxy equivalent 184
-194 * 2) Epicoat # 1001: Epoxy resin; manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 450-500 * 3) Epicoat # 1004: epoxy resin; manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 875-975 * 4) Diinal HR-634: Hydroxyl group-containing acrylic resin; manufactured by Mitsubishi Rayon Co., Ltd., solid content: 50%, hydroxyl value: 22 mgKOH / g, acid value: 8 mgKOH / g,
Weight average molecular weight: 50000 * 5) Cymel # 303: Methylated melamine resin; manufactured by Mitsui Cytec Co., Ltd., solid content 100% * 6) Naicure # 5225: acid catalyst; manufactured by King Industry Co., Ltd., 25% active ingredient * 7) DBU: 1,8-diazabicyclo [5,4,0] undecene-7

<Examples 1 to 5, Comparative Examples 1 to 16> Table 3,
The thermosetting coating composition (A-1 to A-21) described in 4 and "Taipaque CR-95" (titanium oxide manufactured by Ishihara Sangyo Co., Ltd.) should be 1/1 in terms of solid content mass ratio. After mixing and dispersing and kneading with a known disperser such as a sand mill, a mixed solvent consisting of butyl cellosolve (ethylene glycol monobutyl ether) / Solvesso # 150 (Esso Co., aromatic hydrocarbon) = 1/2 (mass%) Was added to prepare a coating material having a solid content of 40% to prepare a coating material. The thermosetting coating composition (A-16) had a high viscosity and could not be dispersed and kneaded by the above method to form a coating material.

This coating material was applied on a tin plate having a thickness of 0.3 mm so as to have a dry film thickness of 10 μm by using a bar coater and baked at 190 ° C. for 10 minutes. Table 5 shows the evaluation results of the obtained coating films.

[0066]

[Table 5]

The evaluation of the performance in the examples and comparative examples was carried out by using the methods described below. [Evaluation Criteria] 7: Very Good, 6: Good, 5: Good, 4: Fair (Practical Lower Limit), 3: Bad, 2: Bad, 1: Very Bad [Evaluation Method] -Coating Film hardness: Pencil scratch test (JIS K-540
The evaluation was performed according to 0).・ Adhesion: 10 in a 1 cm square on the coated surface with a cutter knife
Zero grids were created, cellophane tape was attached, and the state of the coated plate after peeling was visually evaluated.

Impact resistance: Using a DuPont impact tester,
Evaluation was performed under the conditions of 1/2 inch diameter, 1 kg load and 40 cm height, and the state of the coated plate after the evaluation was visually evaluated. -Workability: evaluated according to the Erichsen test (JIS Z-2247). -Solvent resistance: After 100 times of rubbing xylene, the state of the coated plate was visually evaluated.・ Retort resistance: Using a pressure cooker tester,
After the coated plate was immersed in hot water at 130 ° C. for 45 minutes, an adhesion test was conducted and visually evaluated. · Yellowing resistance: The coated plate is further baked at 190 ° C for 10 minutes,
It was evaluated visually. -Paint storage stability: After the paint was left at 50 ° C for 45 days, it was evaluated by the change in the state of the paint and the change in viscosity.

As is clear from each of the examples in Table 5, the coating material containing the thermosetting coating composition of the present invention can form a coating film having a good balance of coating hardness and processability and is resistant to retort. Other coating properties, such as resistance and yellowing resistance, were excellent. The storage stability of the paint was also excellent.

On the other hand, Comparative Example 1 is different from the thermosetting coating composition of the present invention in that it is composed of a hydroxyl group-containing acrylic resin and a melamine resin, which has a high impact resistance of the coating film. The workability was low. Moreover, Comparative Examples 12 to 1
In No. 6, an acrylic copolymer excluding the metal-containing polymerizable monomer (c) in the present invention is used, in which a known compound having a curing promoting action as in Comparative Examples 12 to 15 is added. All of the coating compositions comprising the resin compositions had low storage stability and low yellowing resistance of the coating film. On the other hand, Comparative Example 16 containing no compound having a curing-accelerating action had low solvent resistance and retort resistance.

Further, in Comparative Examples 2 to 10, the coatings containing the resin composition which did not satisfy the conditions specified in the present invention, the balance of hardness and workability of the cured coating, retort resistance, yellowing resistance, etc. However, it was not possible to satisfy all other coating film performances and storage stability of the paint.

[0072]

As described above, the thermosetting coating composition of the present invention comprises the α, β-monoethylenically unsaturated carboxylic acid (a) in an amount of 2 to 30% by mass and represented by the general formula (I). Hydroxyl group-containing (meth) acrylic acid ester (b) and / or carboxyl group-containing (meth) represented by the general formula (II)
Acrylic ester (c) 3 to 30% by mass, metal-containing polymerizable monomer (d) 0.1 to 10% by mass, these (a) component, (b) component and / or (c) component and (d). )
Vinyl monomer (e) 30-94.9 copolymerizable with the components
Obtained by copolymerizing mass% with an acid value of 15 to 150 mg
KOH / g and weight average molecular weight of 3000 to 800
Acrylic copolymer (A) in the range of 00 and an epoxy compound (B) having two or more glycidyl groups in the molecule are contained, and the total amount of the components (A) and (B) is 1
Since the component (A) is 50 to 95 parts by mass in 00 parts by mass, it is possible to form a coating film having excellent balance between coating film hardness and processability, retort resistance and yellowing resistance, Furthermore, it has excellent storage stability when used as a paint. Such a thermosetting coating composition can be suitably used especially as a metal coating material, and is very useful industrially.

Further, the metal-containing polymerizable monomer (d)
Is a metal-containing polymerizable monomer (d1) represented by the general formula (III) and / or a metal-containing polymerizable monomer (d2) having two unsaturated groups, the coating film resistance The retort property is good, and the storage stability of the paint and the yellowing resistance of the coating film are good. Further, the coating material of the present invention,
Since it contains the thermosetting coating composition of the present invention, it is possible to form a coating film having excellent balance between coating film hardness and processability, retort resistance and yellowing resistance, and storage stability. Excellent, especially useful as a paint for metals.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J038 CC021 CC081 CF031 CG141                       CG161 CG171 CH031 CH041                       CH071 CH081 CH121 CH201                       DB002 GA01 GA02 GA03                       GA06 GA16 KA03 KA06 MA14                       NA14 NA26 NA27 PB04 PC02

Claims (5)

[Claims] 1. An α, β-monoethylenically unsaturated carboxylic acid (a) of 2 to 30% by mass, a hydroxyl group-containing (meth) acrylic acid ester (b) represented by the following general formula (I) and / or the following: Carboxyl group-containing (meth) acrylic acid ester (c) represented by general formula (II) 3 to 30% by mass, metal-containing polymerizable monomer (d) 0.1 to 10% by mass, and these (a) components , (B) component and / or (c) component,
Vinyl monomer (e) 30 to 9 copolymerizable with component (d)
4.9 mass% copolymerized with an acid value of 15
~ 150 mg KOH / g, with a weight average molecular weight of 30
Acrylic copolymer (A) in the range of 0-800000, and an epoxy compound (B) having two or more glycidyl groups in the molecule, containing the (A) component and the (B) component. In 100 parts by mass in total,
A thermosetting coating composition, wherein the component (A) is 50 to 95 parts by mass. [Chemical 1] (In the formula, R ¹ is a hydrogen atom or a methyl group, p is an integer of 2 to 8, q is an integer of 2 to 5, and m is an integer of 1 to 10.) (In the formula, R ¹ is a hydrogen atom or a methyl group, r is an integer of 2 to 8, s is an integer of 2 to 5, and n is an integer of 1 to 10,
R ² represents a hydrocarbon substituent having 1 to 8 carbon atoms) 2. The metal-containing polymerizable monomer (d) is a metal-containing polymerizable monomer (d1) represented by the general formula (III).
The thermosetting coating composition according to claim 1, wherein [Chemical 3] (In the formula, R ¹ is a hydrogen atom or a methyl group, M is Mg, Z
n, Ca, or R ³ represents an organic acid residue. ) 3. The metal-containing polymerizable monomer (d) is 2
2. The thermosetting coating composition according to claim 1, which is a metal-containing polymerizable monomer (d2) having a number of unsaturated groups. 4. The metal-containing polymerizable monomer (d) is the metal-containing polymerizable monomer (d1) represented by the general formula (III).
And a metal-containing polymerizable monomer having two unsaturated groups (d
2. The thermosetting coating composition according to claim 1, which is a mixture with 2). [Chemical 4] (In the formula, R ¹ is a hydrogen atom or a methyl group, M is Mg, Z
n, Ca, or R ³ represents an organic acid residue. ) 5. A paint comprising the thermosetting coating composition according to any one of claims 1 to 4.