JP2018127570A - Coating composition and metal packaging material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel coating composition having excellent curability, ink suitability and temporal stability without generating formaldehyde during curing.SOLUTION: The above described problem is solved by a coating composition containing a polymer (A) having a constitutional unit (a1) having an unsaturated dibasic acid skeleton and a constitutional unit (a2) derived from α-olefin having 6 to 18 carbon atoms, and a polymer (B) having a hydroxyl group, excluding the case where it is the polymer (A). Here, the constitutional unit (a1) having the unsaturated dibasic acid skeleton contains a constitutional unit (a1-1) derived from unsaturated dibasic acid monoester.SELECTED DRAWING: None

Description

  The present invention relates to a coating composition, more specifically to a coating composition for coating a metal packaging material, and more particularly to a coating composition suitable for coating the outer surface of a metal packaging material.

  Conventionally, there is a coating composition in which an amino resin is combined as a curing agent with respect to an acrylic resin or a polyester resin. Since amino resins are excellent in curability in a short time, this coating composition is widely used.

  In many cases, metal packaging materials typified by beverage cans and food cans are coated with printing ink on the outer surface of the base metal or film-coated metal, and then the outer surface top coat paint Is painted. Amino resins are widely used as outer surface topcoat paints because of their excellent affinity with ink layers (ink suitability), but the problem is that they generate formaldehyde during curing.

  Thus, a paint using a copolymer containing styrene and maleic anhydride has been proposed as a paint that does not generate formaldehyde during curing (Patent Document 1). However, although the above problems could be solved, excellent curability and ink suitability in a short time could not be sufficiently achieved. In addition to the above-mentioned problems, there has not yet been reported a paint that is excellent in stability over time in a single liquid state.

JP-A-2015-78327

  An object of the present invention is to provide a novel coating composition having excellent curability, ink suitability, and stability over time without generating formaldehyde during curing.

  In order to solve the above problems, the present inventors have conducted intensive studies, and as a result, a polymer having a structural unit (a1-1) derived from an unsaturated dibasic acid monoester and a structural unit (a2) derived from an α-olefin ( It has been found that the above-mentioned problems can be solved by using a coating composition containing A) and a polymer (B) having a hydroxyl group.

  That is, the present invention relates to a polymer (A) having a structural unit (a1) having an unsaturated dibasic acid skeleton and a structural unit (a2) derived from an α-olefin having 6 to 18 carbon atoms, and a polymer having a hydroxyl group. (B) (excluding the case where it is a polymer (A)), wherein the structural unit (a1) having an unsaturated dibasic acid skeleton is an unsaturated dibasic acid monoester It is related with the coating composition containing the structural unit (a1-1) derived from.

  This invention relates to the said coating composition in which the alcohol (a3) which comprises unsaturated dibasic acid monoester contains a C1-C4 aliphatic alcohol.

  The present invention relates to the above-mentioned paint comprising 80.0 mol% or more of a structural unit (a1-1) derived from an unsaturated dibasic acid monoester with respect to 100 mol% of the structural unit (a1) having an unsaturated dibasic acid skeleton. Relates to the composition.

  The present invention relates to the coating composition, wherein the structural unit (a1) having an unsaturated dibasic acid skeleton further includes a structural unit (a1-2) derived from an unsaturated dibasic acid monoamide.

  The present invention relates to the above-mentioned paint comprising 0.1 to 20 mol% of the structural unit (a1-2) derived from unsaturated dibasic acid monoamide with respect to 100 mol% of the structural unit (a1) having an unsaturated dibasic acid skeleton. Relates to the composition.

  The present invention relates to the coating composition, wherein the amine (a4) constituting the unsaturated dibasic acid monoamide contains diethanolamine and / or monoethanolamine.

  The present invention further relates to the coating composition containing a halide of a quaternary ammonium salt and / or a quaternary phosphonium salt.

The present invention relates to the coating composition, which is for coating a metal packaging material.
The present invention relates to a metal packaging material whose outer surface is coated with the coating composition.

  According to the present invention, a novel coating composition having excellent curability, ink suitability, and stability over time could be provided.

<Polymer (A)>
The polymer (A) of the present invention is a monomer polymer having an unsaturated bond, derived from the structural unit (a1) having an unsaturated dibasic acid skeleton and an α-olefin having 6 to 18 carbon atoms. It will not specifically limit if the structural unit (a1) which has a structural unit (a2) and has an unsaturated dibasic acid skeleton contains the structural unit (a1-1) derived from unsaturated dibasic acid monoester. In the present specification, the structural unit refers to a structure (repeating unit) derived from a monomer that is a raw material of a copolymer.
The method for obtaining the polymer having the structural unit (a1) having an unsaturated dibasic acid skeleton is not particularly limited, and examples thereof include a method of copolymerizing a monomer having an unsaturated dibasic acid skeleton. Other methods include a method of modifying a copolymer (precursor) obtained by polymerizing a monomer capable of forming the structural unit (a1) having an unsaturated dibasic acid skeleton. A method of copolymerizing a saturated dibasic acid anhydride and monoesterifying with an alcohol is mentioned.

<Structural Unit (a1) Having Unsaturated Dibasic Acid Skeleton>
In this specification, the structural unit (a1) having an unsaturated dibasic acid skeleton represents a structural unit derived from an unsaturated dibasic acid and an unsaturated dibasic acid. Examples include unsaturated dibasic acid, unsaturated dibasic acid anhydride, unsaturated dibasic acid monoester, unsaturated dibasic acid diester, unsaturated dibasic acid monoamide, unsaturated dibasic acid diamide, unsaturated And dibasic acid imide.
The unsaturated dibasic acid is not particularly limited as long as it is a dicarboxylic acid having an ethylenically unsaturated double bond, and examples thereof include maleic acid, fumaric acid, itaconic acid, citraconic acid, and mesaconic acid. Of these, maleic acid and itaconic acid are preferable from the viewpoint of radical polymerization reactivity.

<Constitutional unit derived from unsaturated dibasic acid monoester (a1-1)>
The polymer (A) is a structural unit (a1-1) derived from an unsaturated dibasic acid monoester obtained by modifying an unsaturated dibasic acid with an alcohol (a3) as a structural unit (a1) having an unsaturated dibasic acid skeleton. )including. The structural unit (a1-1) derived from the unsaturated dibasic acid monoester is not limited to the following examples, but examples thereof include maleic acid monoester and itaconic acid monoester.
Examples of maleic acid monoesters include, for example:
Monomethyl maleate, monoethyl maleate, mono (n-propyl) maleate, monoisopropyl maleate, mono (n-butyl) maleate, monoisobutyl maleate, mono (sec-butyl) maleate, mono (tert -Butyl), mono (n-pentyl) maleate, mono (n-hexyl) maleate, monocyclohexyl maleate, mono (2-ethylhexyl) maleate, and the like.
As the itaconic acid monoester, for example,
Itaconic acid monomethyl, Itaconic acid monoethyl, Itaconic acid mono (n-propyl), Itaconic acid monoisopropyl, Itaconic acid mono (n-butyl), Itaconic acid monoisobutyl, Itaconic acid mono (sec-butyl), Itaconic acid mono (tert) -Butyl), itaconic acid mono (n-pentyl), itaconic acid mono (n-hexyl), itaconic acid monocyclohexyl, itaconic acid mono (2-ethylhexyl), and the like.

<Alcohol (a3)>
The alcohol (a3) constituting the unsaturated dibasic acid monoester is not particularly limited as long as it is a monofunctional alcohol.
Aliphatic alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-pentanol, cyclohexanol, 2-ethylhexanol,
Examples thereof include ether alcohols such as ethyl glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether.
Of these, aliphatic alcohols having 1 to 4 carbon atoms are preferable because of excellent stability over time, and linear aliphatic alcohols having 1 to 4 carbon atoms are more preferable because they exhibit excellent curability.

  In 100 mol% of alcohol (a3), the aliphatic alcohol having 1 to 4 carbon atoms is preferably 50 mol% or more, and more preferably 80 mol% or more.

<Constitutional unit derived from unsaturated dibasic acid monoamide (a1-2)>
The polymer (A) is a structural unit derived from an unsaturated dibasic acid monoamide obtained by modifying an unsaturated dibasic acid with an amine (a4) as a structural unit (a1) having an unsaturated dibasic acid skeleton (a1-2). ). The structural unit (a1-2) derived from the unsaturated dibasic acid monoamide is not limited to the following examples, but examples include maleic acid monoamide and itaconic acid monoamide.
Examples of maleic acid monoamides include, for example, 3- (2-hydroxyethylcarbamoyl) acrylic acid (monoethanolamine-modified maleic acid), 4-oxo-4- [bis (2-hydroxyethyl) amino] 2- Butenoic acid (diethanolamine modified product of maleic acid) and the like.

<Amine (a4)>
The amine (a4) constituting the unsaturated dibasic acid monoamide is not particularly limited as long as it is a monofunctional amine.
Primary amines such as methylamine, ethylamine, isopropylamine, n-butylamine, tert-butylamine, cyclohexylamine, 2-ethylhexylamine, monomethanolamine, monoethanolamine, monoisopropanolamine,
Secondary amines such as dimethylamine, diethylamine, diisopropylamine, di (n-butyl) amine, di (tert-butyl) amine, dicyclohexylamine, di (2-ethylhexyl) amine, dimethanolamine, diethanolamine, diisopropanolamine .
Among these, amines having a hydroxyl group such as diethanolamine and monoethanolamine are preferably used because they are excellent in curability.

  In 100 mol% of the amine (a4), the amine having a hydroxyl group is preferably 50 mol% or more, more preferably 80 mol% or more.

  Among 100 mol% of the structural unit (a1) having an unsaturated dibasic acid skeleton contained in the polymer (A), the structural unit (a1-1) derived from the unsaturated dibasic acid monoester is 80 mol% or more. It is preferable that 85 mol% or more is more preferable, and 90 mol% or more is particularly preferable. When it is 80 mol% or more, it is excellent in ink suitability (curability when coated on the ink layer) and stability over time, and when it is 90 mol% or more, it is particularly excellent in stability over time.

  The polymer (A) preferably further contains a structural unit (a1-2) derived from an unsaturated dibasic acid monoamide. Of 100 mol% of the structural unit (a1) having an unsaturated dibasic acid skeleton, the structural unit (a1-2) derived from the unsaturated dibasic acid monoamide is preferably 0.1 to 20 mol%. 0.1-15 mol% is more preferable, and 0.1-10 mol% is especially preferable. When it is 0.1 mol% or more, the stability over time is excellent. In the case of 15 mol% or less, the ink suitability is excellent, and in the case of 10 mol% or less, the ink suitability is particularly excellent.

The structural unit (a1) having an unsaturated dibasic acid skeleton is a structural unit (a1-3) having an unsaturated dibasic acid skeleton other than the structural unit (a1-1) and the structural unit (a1-2). 0 to 19.9 mol% is preferable, 0 to 14.9 mol% is more preferable, and 0 to 9.9 mol% is particularly preferable. In the case of 19.9 mol% or less, ink suitability and stability over time are excellent.
The ratio of each structural unit is (a1-1) / (a1-2) / (a1-3) = 80 to 99.9 mol% / 0.1 to 15 mol% / 0 to 19.9 mol% Is preferred.

<Constitutional unit derived from α-olefin (a2)>
In the present invention, the α-olefin refers to an unsaturated hydrocarbon represented by C _n H _2n having an ethylenically unsaturated bond at the α-position (n is an integer of 1 or more). Although it does not specifically limit as an example of a C6-C18 alpha olefin,
Examples thereof include 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and the like.
Of these, those having 6 to 10 carbon atoms are preferred, and those having 6 to 8 carbon atoms are particularly preferred. Since it is excellent in ink suitability within the above range, it is preferably used.

In 100 mol% of the structural unit in the polymer (A), the structural unit (a1) having an unsaturated dibasic acid skeleton and the structural unit (a2) derived from α-olefin are preferably 35 mol% to 65 mol%. 45 mol% to 55 mol% is particularly preferable. When the structural unit (a1) having an unsaturated dibasic acid skeleton is 35 mol% or more, the curability is excellent, and when it is 65 mol% or less, the ink suitability is excellent. When the structural unit (a2) derived from α-olefin is 35 mol% or more, the ink suitability is excellent, and when it is 65 mol% or less, the curability is excellent.
The polymer (A) may have other structural units other than the structural unit (a1) having an unsaturated dibasic acid skeleton and the structural unit (a2) derived from α-olefin. In 100 mol% of the structural unit in A), the other structural unit is preferably 0 mol% to 30 mol%, particularly preferably 0 mol% to 10 mol%.

  As other structural units other than the structural unit (a1) having an unsaturated dibasic acid skeleton and the structural unit (a2) derived from an α-olefin, particularly a polymerizable structural unit having an unsaturated double bond can be used. Although not limited, For example, (meth) acrylates, (meth) acrylamides, styrenes, vinyl ethers, vinyl esters are mentioned.

Examples of (meth) acrylates include:
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) Acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) Acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, docosyl (meth) acrylate, etc. Alkyl (meth) acrylate,
Cyclohexyl (meth) acrylate, 3-cyclohexenylmethyl (meth) acrylate, 2,2,4-trimethylcyclohexyl (meth) acrylate, tert-butylcyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 1-adamantyl (meth) Acrylate, 2-methyl-2-adamantyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate, 3-hydroxy-1-adamantyl (meth) acrylate, perfluoro-1-adamantyl (meth) acrylate, di Cycloalkyl (meth) acrylates such as cyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate,
3-methyl-3- (meth) acryloyloxymethyl-1-oxetane, 3-ethyl-3- (meth) acryloyloxymethyl-1-oxetane, 5-ethyl-5- (meth) acryloyloxymethyl-1,3 -Dioxane, tetrahydrofurfuryl (meth) acrylate, (2-ethyl-2-methyl-1,3-dioxolan-4-yl) methyl (meth) acrylate, 1,4-dioxaspiro [4,5] dec-2- Yl) methyl (meth) acrylate, 3- (meth) acryloyloxy-1-oxolan-2-one and other heterocycle-containing (meth) acrylates having an oxygen atom,
N- (meth) acryloyloxyethyl hexahydrophthalimide, 1,2,2,6,6-pentamethyl-4-piperidyl (meth) acrylate, 2,2,6,6-tetramethyl-4-piperidyl (meth) acrylate , Heterocycle-containing (meth) acrylates having nitrogen atoms such as (meth) acryloylmorpholine,
2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 2- (2-ethoxyethoxy) ethyl (meth) acrylate, methoxypolypolyethylene glycol (meth) acrylate, (Meth) acrylate having an oxyalkylene group such as ethoxypolyethyleneglycol mono (meth) acrylate, phenoxypolyethyleneglycol (meth) acrylate, nonylphenoxypolyethyleneglycol (meth) acrylate, methoxypolypropyleneglycol (meth) acrylate,
Examples include tertiary amino group-containing (meth) acrylates such as N, N-dimethylaminoethyl (meth) acrylate and N, N-diethylaminoethyl (meth) acrylate.
Examples of (meth) acrylamides include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, and N-butyl (meth) acrylamide. , Isobutyl (meth) acrylamide, t-butyl (meth) acrylamide, t-octyl (meth) acrylamide, diacetone (meth) acrylamide, N- (3,5-dimethyl-4-glycidyl) benzylacrylamide, and the like. .
Examples of styrenes include styrene, α-methyl styrene, vinyl toluene, chloromethyl styrene, 4-hydroxystyrene, vinyl naphthalene, o-vinyl benzyl glycidyl ether, m-vinyl benzyl glycidyl ether, p-vinyl benzyl glycidyl ether, α-methyl-o-vinylbenzylglycidyl ether, α-methyl-m-vinylbenzylglycidylether, α-methyl-p-vinylbenzylglycidylether, 2,3-diglycidyloxymethylstyrene, 2,4-diglycidyloxy Methylstyrene, 2,5-diglycidyloxymethylstyrene, 2,6-diglycidyloxymethylstyrene, 2,3,4-triglycidyloxymethylstyrene, 2,3,5-triglycidyloxymethylstyrene, 2 3,6 triglycidyl oxymethyl styrene, 3,4,5-glycidyloxy-methylstyrene, 2,4,6-glycidyloxy-methylstyrene, and the like.
As vinyl ethers, for example,
Examples thereof include ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether, and the like.
Examples of vinyl esters include vinyl acetate and vinyl propionate.

In the polymerization of the polymer (A), it is preferable to arbitrarily use 0.001% to 15 mol% of a polymerization initiator with respect to 100 mol% of the structural unit. As the polymerization initiator, a known polymerization initiator can be used, and it is preferable to use an azo compound and an organic peroxide.
Examples of azo compounds include, for example,
2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane 1-carbonitrile), 2,2′-azobis (2, 4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2′-azobis (2-methylpropionate), 4,4′-azobis ( 4-cyanovaleric acid), 2,2′-azobis (2-hydroxymethylpropionitrile), 2,2′-azobis [2- (2-imidazolin-2-yl) propane] and the like.
Examples of organic peroxides include, for example:
Benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di (2-ethoxyethyl) peroxydicarbonate, t-butylperoxyneo Examples include decanoate, t-butyl peroxybivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, and diacetyl peroxide.
These polymerization initiators can be used alone or in combination of two or more.

In the polymerization of the polymer (A), a chain transfer agent may be used for the purpose of adjusting the molecular weight. It is preferable to arbitrarily use 0.001 to 15 parts by weight of a chain transfer agent with respect to 100 mol% of the structural unit. The chain transfer agent is not particularly limited as long as it is a compound capable of adjusting the molecular weight, and a known chain transfer agent can be used.
For example, octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thioapple Mercaptans such as acids, octyl thioglycolate, octyl 3-mercaptopropionate, 2-mercaptoethanesulfonic acid, butylthioglycolate;
Disulfides such as dimethylxanthogen disulfide, diethylxanthogen disulfide, diisopropylxanthogen disulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide;
Halogenated hydrocarbons such as carbon tetrachloride, methylene chloride, bromoform, bromotrichloroethane, carbon tetrabromide, ethylene bromide;
Secondary alcohols such as isopropanol, glycerin;
Phosphorous acid, hypophosphorous acid, and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, hydrogen sulfite, dithionite, metabisulfite, and salts thereof (sodium hydrogen sulfite) Lower oxides and salts thereof, such as potassium bisulfite, sodium dithionite, potassium dithionite, sodium metabisulfite, potassium metabisulfite);
And allyl alcohol, 2-ethylhexyl thioglycolate, α-methylstyrene dimer, terpinolene, α-terpinene, γ-terpinene, dipentene, anisole and the like. These may be used alone or in combination of two or more.

In the polymerization of the polymer (A), an organic solvent can be used as a polymerization solvent. As an organic solvent, it is preferable to use the solvent used for the coating composition concerning this invention.
For example, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, ethyl acetate, butyl acetate, isobutyl acetate, toluene, xylene, acetone, hexane, methyl ethyl ketone , Cyclohexanone, propylene glycol monomethyl ether acetate, diethoxydiethylene glycol, ethyl 3-ethoxypropionate, butanediol diacetate, and the like.
Among these, when polymerizing with an unsaturated dibasic acid or an unsaturated dibasic acid anhydride and then modifying to an unsaturated dibasic acid monoester (a1-1) using an alcohol (a3), as a polymerization solvent Is preferably an alcohol having no hydroxyl group, and diethylene glycol dimethyl ether, methyl ethyl ketone, and cyclohexanone are preferably used.
These polymerization solvents may be used as a mixture of two or more.

As a polymerization method of the polymer (A), a known method can be used, and it is not limited to the following example. However, for example, a batch method or a dropping method can be used, and these may be used in combination. The batch method is preferable because unreacted monomers and low polymers can be reduced and the curability is excellent, and the dropping method is preferable because heat generation and runaway reaction can be suppressed. When the total amount of raw materials is 100% by mass, the proportion charged in the reaction vessel in advance (batch method) is preferably 20% by mass to 80% by mass, and the proportion charged by the dropping method is preferably 20% by mass to 80% by mass. More preferably, they are 40 mass%-60 mass% and 60 mass%-40 mass%, respectively.

The polymer (A) is a monoester modified product of a copolymer of a monomer containing an unsaturated dibasic acid anhydride and an α-olefin having 6 to 18 carbon atoms, or an unsaturated dibasic acid anhydride and Monoester and monoamide modified products of a monomer copolymer containing an α-olefin having 6 to 18 carbon atoms are preferable, and these are an unsaturated dibasic acid anhydride and an α-olefin having 6 to 18 carbon atoms. It is obtained by obtaining a copolymer of monomers containing, followed by modification with alcohol and / or amine. Although it does not specifically limit as a modification method, It is preferable to carry out amine modification after monoester modification.

In the above synthesis method, the acid anhydride value of the copolymer which is the precursor of the polymer (A) is preferably from 100 to 400 mgKOH / g, more preferably from 200 to 300 mgKOH / g.

  The molecular weight of the polymer (A) is preferably 1,000 to 30,000, more preferably 8,000 to 15,000. When the molecular weight is 1,000 or more, the curability is excellent, and when the molecular weight is 30,000 or less, the viscosity is kept low, and thus the coating property is excellent. When the molecular weight is 8,000 or more, the curability is excellent, and when the molecular weight is 15,000 or less, the ink suitability is excellent.

<Polymer (B)>
The polymer (B) (except for the case of the polymer (A)) is not particularly limited as long as it has a hydroxyl group. The hydroxyl group in the polymer (B) forms a crosslinking reaction with the polymer (A) in the heating step and gives excellent curability.

  The polymer (B) can be obtained by copolymerizing a monomer having a hydroxyl group and, if necessary, another monomer according to a conventional method.

As a monomer having a hydroxyl group,
For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxy Alkyl (meth) acrylates such as butyl (meth) acrylate and ethyl-α-hydroxymethyl acrylate,
2-hydroxy-3-phenoxypropyl (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, monohydroxyethyl (meth) acrylate phthalate, p-hydroxyphenylethyl (meth) acrylate, 2,3- (Meth) acrylates such as mono (meth) acrylates of polyols such as dihydroxypropyl (meth) acrylate, polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetramethylene glycol, polyester, polycaprolactone, polybutadiene,
Acrylamides such as N- (2-hydroxyethyl) (meth) acrylamide,
And vinyl ethers such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, and cyclohexanedimethanol monovinyl ether.

Those having a primary hydroxyl group are preferred from the viewpoint of curability.
For example, among the above, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, ethyl-α-hydroxymethyl acrylate, cyclohexanedimethanol mono (meth) acrylate, N -(2-hydroxyethyl) (meth) acrylamide, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, cyclohexane dimethanol monovinyl ether, and the like. Particularly preferred are alkyl (meth) acrylates having a primary hydroxyl group, such as 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate.

You may use the monomer which has a carboxy group as another monomer.
For example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and the like can be mentioned.
In this case, the acid value is preferably from 0 to 100 mgKOH / g, more preferably from 10 to 60 mgKOH / g. When it is in the above range, curability is improved.

Other monomers include, for example,
Styrenes: Styrene, α-methyl styrene, vinyl toluene, chloromethyl styrene, 4-hydroxystyrene, vinyl naphthalene, o-vinyl benzyl glycidyl ether, m-vinyl benzyl glycidyl ether, p-vinyl benzyl glycidyl ether, α-methyl- o-vinylbenzylglycidyl ether, α-methyl-m-vinylbenzylglycidyl ether, α-methyl-p-vinylbenzylglycidyl ether, 2,3-diglycidyloxymethylstyrene, 2,4-diglycidyloxymethylstyrene, 2 , 5-diglycidyloxymethylstyrene, 2,6-diglycidyloxymethylstyrene, 2,3,4-triglycidyloxymethylstyrene, 2,3,5-triglycidyloxymethylstyrene, 2,3,6-trig Glycidyloxy-methylstyrene, 3,4,5-glycidyloxy-methylstyrene, 2,4,6-glycidyloxy-methylstyrene,
(Meth) acrylates; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) Acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) Acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, docosyl Meth) alkyl acrylates such as (meth) acrylate,
Cyclohexyl (meth) acrylate, 3-cyclohexenylmethyl (meth) acrylate, 2,2,4-trimethylcyclohexyl (meth) acrylate, tert-butylcyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 1-adamantyl (meth) Acrylate, 2-methyl-2-adamantyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate, 3-hydroxy-1-adamantyl (meth) acrylate, perfluoro-1-adamantyl (meth) acrylate, di Cycloalkyl (meth) acrylates such as cyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate,
Glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, 4- (glycidyloxy) butyl (meth) acrylate, 3-methyl-3,4-epoxybutyl (meth) acrylate, 3-ethyl-3,4-epoxybutyl (Meth) acrylate, 4-methyl-4,5-epoxypentyl (meth) acrylate, 5-methyl-5,6-epoxyhexyl (meth) acrylate, glycidyl α-ethyl acrylate, crotonyl glycidyl ale, (iso) Crotonic acid glycidyl ether, epoxy group-containing (meth) acrylate such as (3,4-epoxycyclohexyl) methyl (meth) acrylate,
3-methyl-3- (meth) acryloyloxymethyl-1-oxetane, 3-ethyl-3- (meth) acryloyloxymethyl-1-oxetane, 5-ethyl-5- (meth) acryloyloxymethyl-1,3 -Dioxane, tetrahydrofurfuryl (meth) acrylate, (2-ethyl-2-methyl-1,3-dioxolan-4-yl) methyl (meth) acrylate, 1,4-dioxaspiro [4,5] dec-2- Yl) methyl (meth) acrylate, 3- (meth) acryloyloxy-1-oxolan-2-one and other heterocycle-containing (meth) acrylates having an oxygen atom,
N- (meth) acryloyloxyethyl hexahydrophthalimide, 1,2,2,6,6-pentamethyl-4-piperidyl (meth) acrylate, 2,2,6,6-tetramethyl-4-piperidyl (meth) acrylate , Heterocycle-containing (meth) acrylates having nitrogen atoms such as (meth) acryloylmorpholine,
2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 2- (2-ethoxyethoxy) ethyl (meth) acrylate, methoxypolypolyethylene glycol (meth) acrylate, (Meth) acrylate having an oxyalkylene group such as ethoxypolyethyleneglycol mono (meth) acrylate, phenoxypolyethyleneglycol (meth) acrylate, nonylphenoxypolyethyleneglycol (meth) acrylate, methoxypolypropyleneglycol (meth) acrylate,
Tertiary amino group-containing (meth) acrylates such as N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate,
(Meth) acrylamides; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, isobutyl (meth) ) Acrylamide, t-butyl (meth) acrylamide, t-octyl (meth) acrylamide, diacetone (meth) acrylamide, N- (3,5-dimethyl-4-glycidyl) benzylacrylamide,
(Meth) acrylonitriles; (meth) acrylonitrile vinyl ethers, allyl ethers; ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether, allyl glycidyl ether,
Vinyl esters; vinyl acetate, vinyl maleimide propionates; maleimide, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide,
N-vinylamides; N-vinylformamide, N-vinylacetamide, N-vinyl-2-pyrrolidone, N-vinylcaprolactam,
Itaconic acid diesters; dimethyl itaconate, diethyl itaconate, di (n-propyl) itaconate, diisopropyl itaconate, di (n-butyl) itaconate, diisobutyl itaconate, di (2-ethylhexyl) itaconate,
Maleic acid diesters: dimethyl maleate, diethyl maleate, di (n-propyl) maleate, diisopropyl maleate, di (n-butyl) maleate, diisobutyl maleate,
Etc.

In the polymerization, it is preferable to arbitrarily use 0.001 to 15 parts by weight of a polymerization initiator with respect to 100 parts by weight of the above monomers. As the polymerization initiator, a known polymerization initiator can be used, and it is preferable to use an azo compound and an organic peroxide.
Examples of azo compounds include
2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane 1-carbonitrile), 2,2′-azobis (2, 4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2′-azobis (2-methylpropionate), 4,4′-azobis ( 4-cyanovaleric acid), 2,2′-azobis (2-hydroxymethylpropionitrile), 2,2′-azobis [2- (2-imidazolin-2-yl) propane] and the like.
Examples of organic peroxides include
Benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di (2-ethoxyethyl) peroxydicarbonate, t-butylperoxyneo Examples include decanoate, t-butyl peroxybivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, and diacetyl peroxide. These polymerization initiators can be used alone or in combination of two or more.

During the polymerization, a chain transfer agent may be used for the purpose of adjusting the molecular weight. It is preferable to arbitrarily use 0.001 to 15 parts by weight of a chain transfer agent with respect to 100 parts by weight of the total amount of monomers. The chain transfer agent is not particularly limited as long as it is a compound capable of adjusting the molecular weight, and a known chain transfer agent can be used.
For example, octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thioapple Mercaptans such as acids, octyl thioglycolate, octyl 3-mercaptopropionate, 2-mercaptoethanesulfonic acid, butylthioglycolate;
Disulfides such as dimethylxanthogen disulfide, diethylxanthogen disulfide, diisopropylxanthogen disulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide;
Halogenated hydrocarbons such as carbon tetrachloride, methylene chloride, bromoform, bromotrichloroethane, carbon tetrabromide, ethylene bromide;
Secondary alcohols such as isopropanol, glycerin;
Phosphorous acid, hypophosphorous acid, and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, hydrogen sulfite, dithionite, metabisulfite, and salts thereof (sodium hydrogen sulfite) Lower oxides and salts thereof, such as potassium bisulfite, sodium dithionite, potassium dithionite, sodium metabisulfite, potassium metabisulfite);
And allyl alcohol, 2-ethylhexyl thioglycolate, α-methylstyrene dimer, terpinolene, α-terpinene, γ-terpinene, dipentene, anisole and the like. These may be used alone or in combination of two or more.

In the polymerization, an organic solvent can be used as a polymerization solvent. As an organic solvent, it is preferable to use the solvent used for the coating composition concerning this invention.
For example, water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether , Ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, ethyl acetate , Butyl acetate, isobutyl acetate , Toluene, xylene, acetone, hexane, methyl ethyl ketone, cyclohexanone, propylene glycol monomethyl ether acetate, diethoxydiethylene glycol, ethyl 3-ethoxypropionate, butanediol diacetate, etc. are used, but are not particularly limited thereto. . These polymerization solvents may be used as a mixture of two or more.

  The molecular weight of the polymer (B) having a hydroxyl group is preferably 1,000 to 100,000, more preferably 2,000 to 30,000, and particularly preferably 5,000 to 15,000. When the molecular weight is less than 1,000, solvent resistance and coating film hardness may not be sufficient. On the other hand, when the molecular weight exceeds 100,000, problems may occur in the coating process, such as an increase in the viscosity of the coating composition and inability to obtain flatness during coating.

  The hydroxyl value of the polymer (B) having a hydroxyl group is preferably 50 mgKOH / g or more, more preferably 100 to 350 mgKOH / g, and particularly preferably 150 to 300. When the hydroxyl value is less than 50, the solvent resistance and coating film hardness may not be sufficient.

<Halide of quaternary ammonium salt and / or quaternary phosphonium salt>
You may add the catalyst which accelerates | stimulates the crosslinking reaction of a polymer (A) and a polymer (B) to the coating composition of this invention. Examples of the catalyst include quaternary ammonium salts and quaternary phosphonium salts. Specifically, tetramethylammonium salt, tetraethylammonium salt, tetrapropylammonium salt, tetrabutylammonium salt, tetraoctylammonium salt, butyltrimethylammonium salt, dodecyltrimethylammonium salt, tetradecyltrimethylammonium salt, hexadecyltrimethylammonium salt , Octadecyl trimethyl ammonium salt, where sil trimethyl ammonium salt, phenyl trimethyl ammonium salt, benzyl trimethyl ammonium salt, didecyl dimethyl ammonium salt, dicocoyl dimethyl ammonium salt, distearyl dimethyl ammonium salt, dioleyl dimethyl ammonium salt, benzyl dimethyl dodecyl ammonium Salt, tributylmethylammonium salt, trioctylmethylammonium salt Monium salt, hexamethyldimethylethylammonium salt, butyltriethylammonium salt, benzyltriethylammonium salt, benzyltributylammonium salt, tetraphenylphosphonium salt, benzyltriphenylphosphonium salt, methyltriphenylphosphonium salt, ethyltriphenylphosphonium salt, propyltri Phenylphosphonium salt, butyltriphenylphosphonium salt,
Etc.

Examples of the counter anion of the ammonium salt or phosphonium salt include fluoride ion, chloride ion, bromide ion, iodide ion, tribromide ion, triiodide ion, cyanide ion, hydroxide ion, and hydrogen sulfate ion. , Methanesulfonate ion, trifluoromethanesulfonate ion, bis (trifluoromethanesulfonyl) imide ion, tris (trifluoromethanesulfonyl) methide ion, p-toluenesulfonate ion, tetrafluoroborate ion, tetraphenylborate ion, tetrakis (penta Fluorophenyl) borate ion, hexafluorophosphate ion, hexafluoroantimonate ion, acetate ion, perchlorate ion, thiocyanate ion, etc., and halide ion is preferred. Arbitrariness.

  0.1-5 mass% is preferable with respect to 100 mass% of solid content of a coating composition, and, as for the addition amount of a catalyst, 0.3-2 mass% is more preferable. When the amount is less than 0.1% by mass, the performance as a catalyst cannot be exhibited and the curability may be deteriorated. Moreover, when more than 5 mass%, corrosivity becomes strong and there exists a possibility of making a metal base material rust.

  Solvents contained in the coating composition of the present invention are water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, Diethylene glycol dimethyl ether, propylene glycol monomethyl ether, acetic acid ester Butyl acetate, isobutyl acetate, toluene, xylene, acetone, hexane, methyl ethyl ketone, cyclohexanone, propylene glycol monomethyl ether acetate, diethoxydiethylene glycol, ethyl 3-ethoxypropionate, butanediol diacetate, etc. It is not limited.

  In addition to the above, additives such as leveling agents, antifoaming agents, antioxidants, light stabilizers, adhesion promoters, waxes and fillers can be added to the coating composition of the present invention. 0.001 mass%-30 mass% are preferable with respect to 100 mass% of solid content of a coating composition, and, as for the addition amount of these additives, 0.01%-10 mass% are more preferable. When the amount is 0.001% by mass or more, the paintability and the temporal stability of the coating film can be improved, and when it is 30% by mass or less, it is preferable in that excellent curability is obtained.

The coating composition of the present invention can be applied to various substrates. The substrate is not particularly limited, but is preferably a metal wrapping material, for example, an untreated or surface-treated metal such as an aluminum plate, a steel plate, a tin plate, a metal obtained by applying a primer to these metals, or Examples thereof include a PET-coated metal obtained by laminating a polyester film (PET) on these metals.
Moreover, the coating composition of this invention can be used suitably in order to coat | cover the outer surface of a metal packaging material.

  As a method for coating the base material with the coating composition of the present invention, various known methods such as roll coater coating, spray coating, immersion coating, electrodeposition coating, and the like can be applied. As drying conditions for the coated paint, it is usually preferable that the surface temperature of the substrate is 120 ° C. to 300 ° C. for 10 seconds to 30 minutes.

Coating amount after drying may be appropriately selected depending on the application, but usually about 5 to 200 mg / dm ² is preferred.

  The present invention will be described more specifically with reference to the following examples. However, the following examples do not limit the scope of rights of the present invention.

(Measurement of weight average molecular weight)
The weight average molecular weight (Mw) was measured by gel permeation chromatography (GPC). As a measuring instrument, GPC "HPC-8020" manufactured by Tosoh Corporation was used. As the column, a Super HM-M and a Super HM-L manufactured by Tosoh Corporation were connected in series. Tetrahydrofuran (THF) was used as a solvent (eluent), measured at 40 ° C., and shown as a converted value using polystyrene as a standard.

(Acid anhydride value)
The acid anhydride value was calculated from the formula (1).
(Mole number of acid anhydride group contained in 1 g of sample) × 56.1 × 1000 (mgKOH / g)
... Formula (1)

[Ratio of the structural unit (a1) having an unsaturated dibasic acid skeleton]
(Synthesis Examples 13 to 37, Comparative Synthesis Examples 4 to 8)
Of the structural unit (a1) having an unsaturated dibasic acid skeleton, the structural units derived from monoester and monoamide were calculated as follows using a Fourier transform infrared spectrometer. That is, the absorbances of C═O stretching vibration (1785 cm ⁻¹ ) and C—H stretching vibration (2931 cm ⁻¹ ) derived from the acid anhydride group before modification are Abs1, Abs2, respectively, and Abs3, Abs4 after modification, respectively. The rate was calculated by equation (2).
(Constitutional unit derived from monoester)
= (Abs1 / Abs2-Abs3 / Abs4) / (Abs1 / Abs2) × 100
(Mol%) Formula (2)
This reaction was calculated as a monoester-derived structural unit when the alcohol (a3) was used, and as a monoamide-derived structural unit when the amine (a4) was used.

(Synthesis Example 38)
Among monomers having an unsaturated dibasic acid skeleton at the time of polymerizing the polymer (A), the charging ratio of unsaturated dibasic acid monoester was used.

[Synthesis of Precursor of Polymer (A)]
(Synthesis Example 1)
A reaction vessel equipped with a nitrogen gas inlet tube, a condenser, a stirring blade, and a thermometer was charged with 22.2 parts of diethylene glycol dimethyl ether, 13.9 parts of 1-octene, and 12.2 parts of maleic anhydride. The temperature was raised to ° C. Thereafter, 0.5 part of octyl thioglycolate and 0.5 part of perbutyl O (tert-butyl-2-ethylperoxyhexanoate) were added to the reaction tank, and at the same time, 22.2 parts of diethylene glycol dimethyl ether, 1 -A mixed solution in which 13.9 parts of octene, 12.2 parts of maleic anhydride, 0.5 part of octyl thioglycolate and 0.5 part of perbutyl O were uniformly mixed in advance was added dropwise over 2 hours. After 1 hour from the end of dropping, and 2 hours later, 0.3 parts of perbutyl O was added to the reaction vessel. Then, after aging at 90 ° C. for 2 hours, the reaction was terminated by cooling, and a polymer having a structural unit derived from unsaturated dibasic acid and a structural unit derived from α-olefin (solid content 55%, acid anhydride value 253 mgKOH / g) was obtained.

(Synthesis Examples 2-12, Comparative Synthesis Examples 1-3)
Synthesis was performed in the same manner as in Synthesis Example 1 except that the blending ratios shown in Table 1 and Table 2 were changed.

The abbreviations in Table 1 and Table 2 are as follows.
Linearene 124: Mixture of 1-tetradecene and 1-hexadecene (made by Idemitsu Kosan Co., Ltd.)
Linearene 148: Mixture of 1-tetradecene, 1-hexadecene, and 1-octadecene (manufactured by Idemitsu Kosan Co., Ltd.)
EA: ethyl acrylate MMA: methyl methacrylate perbutyl O: tert-butyl-2-ethylperoxyhexanoate (manufactured by NOF Corporation)
OTG: Octyl thioglycolate DMDG: Diethylene glycol dimethyl ether

[Synthesis of Polymer (A)]
(Synthesis Example 13: Polymer A1)
Into a reaction vessel equipped with a nitrogen gas introduction tube, a condenser, a stirring blade, and a thermometer, 1200 parts of the polymer obtained in Synthesis Example 1 was charged, the temperature was raised to 90 ° C., and 226 parts of 1-propanol was added, The reaction was carried out at 90 ° C. for 14 hours. Thereafter, 1-propanol and the solvent diethylene glycol dimethyl ether were distilled off under reduced pressure to prepare a solid content of 50%. The reaction was terminated by cooling to obtain a polymer (A) (polymer A1) having a structural unit (a1-1) derived from an unsaturated dibasic acid monoester and a structural unit (a2) derived from an α-olefin. . The solid content of the polymer is 50%, the structural unit (a1-1) derived from the unsaturated dibasic acid monoester is 84% with respect to 100 mol% of the structural unit (a1) having an unsaturated dibasic acid skeleton, The structural unit (a1-2) derived from unsaturated dibasic acid monoamide was 0%.

(Synthesis Examples 14-19, 24-25, and 27-37, and Comparative Synthesis Examples 4-8: Polymers A2-A7, A12-A13, and A15-A25, and Polymers X1-X5)
The compounds were synthesized in the same manner as in Synthesis Example 13 (Polymer A1) except that the blending ratios shown in Table 3, Table 4, and Table 6 were changed.

(Synthesis Example 20: Polymer A8)
Into a reaction vessel equipped with a nitrogen gas introduction tube, a condenser, a stirring blade, and a thermometer, 1200 parts of the polymer obtained in Synthesis Example 1 was charged, the temperature was raised to 90 ° C., and 226 parts of 1-propanol was added, The reaction was carried out at 90 ° C. for 14 hours. Subsequently, 50 parts of diethanolamine was added dropwise over 1 hour, and the mixture was further reacted at 90 ° C. for 1 hour. Thereafter, 1-propanol and the solvent diethylene glycol dimethyl ether were distilled off under reduced pressure to prepare a solid content of 50%. The reaction is terminated by cooling, the structural unit derived from the unsaturated dibasic acid monoester (a1-1) and the structural unit derived from the unsaturated dibasic acid monoamide (a1-2), and the structural unit derived from the α-olefin ( A polymer (A) (polymer A8) having a2) was obtained. The solid content of the polymer is 50%, the structural unit (a1-1) derived from the unsaturated dibasic acid monoester is 84% with respect to 100 mol% of the structural unit (a1) having an unsaturated dibasic acid skeleton, The structural unit (a1-2) derived from unsaturated dibasic acid monoamide was 13%.

(Synthesis Examples 21 to 23, and Synthesis Example 26: Polymers A8 to A11 and A14)
Synthesis was performed in the same manner as in Synthesis Example 20 (Polymer A8) except that the blending ratios shown in Table 3 were changed.

(Synthesis Example 38: Polymer A26)
A reaction vessel equipped with a nitrogen gas inlet tube, a condenser, a stirring blade, and a thermometer was charged with 25 parts of diethylene glycol dimethyl ether, 11.1 parts of 1-octene, and 12.8 parts of monomethyl maleate, and the mixture was heated to 90 ° C. under a nitrogen stream. The temperature rose. Thereafter, 0.4 part of octyl thioglycolate and 0.5 part of perbutyl O (tert-butyl-2-ethylperoxyhexanoate) were added to the reaction tank, and simultaneously 25 parts of diethylene glycol dimethyl ether and 1-octene were added from the dropping tank. A mixed solution in which 11.0 parts, 12.9 parts of monomethyl maleate, 0.4 parts of octyl thioglycolate and 0.5 part of perbutyl O were previously mixed uniformly was dropped over 2 hours. Perbutyl O was added to the reaction vessel 0.2 part by 1 hour after the completion of dropping and 2 hours. Thereafter, after aging at 90 ° C. for 2 hours, the reaction is terminated by cooling, and a polymer having a structural unit (a1-1) derived from an unsaturated dibasic acid monoester and a structural unit (a2) derived from an α-olefin ( A) (Polymer A26) was obtained. The solid content of this polymer is 50%, the structural unit (a1-1) derived from the unsaturated dibasic acid monoester is 100% with respect to 100 mole% of the structural unit (a1) having an unsaturated dibasic acid skeleton, The structural unit (a1-2) derived from unsaturated dibasic acid monoamide was 0%.

Abbreviations and the like in Table 6 are as follows.
Isoban-600: isobutylene maleic anhydride resin (manufactured by Kuraray Co., Ltd., acid anhydride value 339.3 mg KOH / g),
DMDG: Diethylene glycol dimethyl ether

[Synthesis of polymer (B)]
(Synthesis Example 38: Polymer B1)
A reaction vessel equipped with a nitrogen gas inlet tube, a condenser, a stirring blade, and a thermometer was charged with 1.5 parts of acrylic acid and 49.1 parts of diethylene glycol monobutyl ether, and the temperature was raised to 100 ° C. under a nitrogen stream. Thereafter, a mixed liquid in which 20.2 parts of ethyl acrylate, 22.9 parts of 4-hydroxybutyl acrylate, and 4.5 parts of perbutyl O were uniformly mixed in advance was dropped into the reaction tank over 2 hours. Perbutyl O was added to the reaction vessel 0.4 parts at 1 hour after completion of the dropping and at 2 hours. After aging at 100 ° C. for 2 hours, the reaction was terminated by cooling to obtain a polymer B1 (solid content 50%, hydroxyl value 178 mgKOH / g).

(Synthesis Examples 39 to 42: Polymers B2 to B5)
The polymers B2 to B5 were synthesized in the same manner as the polymer B1 except that the blending ratio shown in Table 7 was changed.

Abbreviations and the like in Table 7 are as follows.
HEMA: 2-hydroxyethyl methacrylate 4HBA: 4-hydroxybutyl acrylate EA: ethyl acrylate AA: acrylic acid IA: perbutyl itaconate O: tert-butyl-2-ethylperoxyhexanoate (manufactured by NOF Corporation)
BDG: Diethylene glycol monobutyl ether

Example 1
A coating composition having a solid content of 37% was prepared by blending 37 parts of polymer (A1), 37 parts of polymer (B1), 0.15 part of tetramethylammonium chloride and 26 parts of diethylene glycol monobutyl ether. Further, this coating composition was applied on an aluminum plate and an aluminum plate coated with printing ink to prepare test pieces (referred to as aluminum and ink, respectively). The printing ink was black ink having an oil-modified polyester resin as a main component of the vehicle, and was printed at 1 g / m ² . The coating composition was applied with a bar coater to 4.5 mg / m ² on each substrate and baked in an electric oven at 200 ° C. for 1 minute.

<Rubbing resistance>
The two bond hammers were covered with 16 layers of gauze moistened with methyl ethyl ketone, and the specimen was rubbed. The number of rubbing times until the coating film was peeled was measured and evaluated according to the following criteria.
A: More than 200 times. Especially excellent.
○: 150 times or more and less than 200 times. Are better.
Δ: 100 times or more and less than 150 times. Can withstand practical use.
X: Less than 100 times. It cannot stand practical use.

<Pencil hardness>
The pencil hardness was tested according to JIS K5600-5-4: 1999 and evaluated according to the following criteria.
A: 4H or more. Especially excellent.
○: 2H to 3H. Are better.
Δ: HB to H. Can withstand practical use.
X: Less than HB. It cannot stand practical use.

<Stability over time>
The stability over time was evaluated by the rate of thickening when the coating composition was stored at 40 ° C. for 2 weeks. The thickening rate was obtained from the formula (3) as the ratio of the difference between the viscosity before aging and the viscosity after aging (V2) to the viscosity before aging (V1).

Thickening rate (%) = (V2−V1) / V1 (3)

Evaluation was performed according to the following criteria.
A: Thickening rate is less than 10%. Especially excellent.
○: Thickening rate is 10% or more and less than 50%. Are better.
Δ: Viscosity increased from 50% to less than 200%. Can withstand practical use.
X: 200% or more, or measurement not possible due to gelation. It cannot stand practical use.

In the same manner as in Example 1, Examples 2 to 30 and Comparative Examples 1 to 5 were performed. The evaluation results are summarized in Table 8, Table 9, and Table 10.

Claims (9)

  A polymer (A) having a structural unit (a1) having an unsaturated dibasic acid skeleton and a structural unit (a2) derived from an α-olefin having 6 to 18 carbon atoms, and a polymer (B) having a hydroxyl group (however, And a structural unit (a1) having an unsaturated dibasic acid skeleton is a structural unit derived from an unsaturated dibasic acid monoester (except for the case of polymer (A)) A coating composition comprising a1-1).   The coating composition according to claim 1, wherein the alcohol (a3) constituting the unsaturated dibasic acid monoester contains an aliphatic alcohol having 1 to 4 carbon atoms.   The structural unit (a1-1) derived from an unsaturated dibasic acid monoester is contained in 80.0 mol% or more with respect to 100 mol% of the structural unit (a1) having an unsaturated dibasic acid skeleton. The coating composition as described.   The coating composition according to any one of claims 1 to 3, wherein the structural unit (a1) having an unsaturated dibasic acid skeleton further includes a structural unit (a1-2) derived from an unsaturated dibasic acid monoamide.   The structural unit (a1-2) derived from unsaturated dibasic acid monoamide is contained in an amount of 0.1 to 20 mol% based on 100 mol% of the structural unit (a1) having an unsaturated dibasic acid skeleton. Paint composition.   The coating composition according to claim 4 or 5, wherein the amine (a4) constituting the unsaturated dibasic acid monoamide contains diethanolamine and / or monoethanolamine.   Furthermore, the coating composition of Claims 1-6 containing the halide of a quaternary ammonium salt and / or a quaternary phosphonium salt.   The coating composition according to claim 1, which is used for coating a metal packaging material. A metal packaging material whose outer surface is coated with the coating composition according to claim 1.