CN114149719A

CN114149719A - Coating composition and application thereof

Info

Publication number: CN114149719A
Application number: CN202111337561.7A
Authority: CN
Inventors: 黄育群; 赖平升; 萧伯卓; 林学全; 林辰羿
Original assignee: Eternal Materials Guangdong Co Ltd
Current assignee: Eternal Materials Guangdong Co Ltd
Priority date: 2021-11-11
Filing date: 2021-11-11
Publication date: 2022-03-08
Anticipated expiration: 2041-11-11
Also published as: CN114149719B

Abstract

The invention provides a coating composition and application thereof. The coating composition of the present invention comprises a vinyl copolymer and an amino resin, the vinyl copolymer being a vinyl copolymer of ethylenically unsaturated monomers, wherein the ethylenically unsaturated monomers include ethylenically unsaturated carboxylic acid monomers, hydroxyl group-containing ethylenically unsaturated monomers, and phosphoric acid group-containing ethylenically unsaturated monomers. Compared with the traditional acrylic acid anode electrophoretic coating, the coating film prepared by the coating composition through anode electrophoretic coating has better extinction property, smoothness and coating hardness, smooth hand feeling, good adherence, and good boiling water resistance, acid resistance, alkali resistance, organic solvent resistance and impact resistance.

Description

Coating composition and application thereof

Technical Field

The invention belongs to the field of coatings, and relates to a coating composition and application thereof. In particular, the invention relates to a coating composition containing vinyl copolymer suitable for preparing a delustering coating film by anodic electrophoretic coating and application thereof.

Background

Electrodeposition coating is a new coating film forming method. The anode electrophoretic coating has low pollution and zero loss, is suitable for automatic production, can treat workpieces with complex shapes, and is widely applied to coating of hardware such as automobiles, motors, mobile phones, household appliances and the like.

The anode electrophoretic paint mainly comprises acrylic acid, polybutadiene, epoxy ester, phenolic resin and the like. The acrylic acid anode electrophoretic coating is prepared by mainly using acrylic acid and polymers of esters thereof as base resin, crosslinking and curing and then neutralizing by using a neutralizer. Currently, there is a delustering acrylic anodic electrodeposition coating composition having a good delustering property, as disclosed in JPH10-245508, which comprises (a) an acrylic polymer, (b) an aluminum complex compound represented by the formula (I), Al (OR)_t(L)_3-t(I) (wherein R represents an alkyl group having 1 or more carbon atoms, L represents a ketol type interdependence compound, and t represents an integer of 0. ltoreq. t.ltoreq.3), (c) a silicon compound represented by the formula (II), and Si (X)¹)_p(OX²)_4-p(2) (wherein, X¹Represents alkyl or phenyl, X¹Which may be the same or different, X²Indicating a hydrogen atom or an alkyl group, X²And m is an integer of 0. ltoreq. p.ltoreq.3) and (d) an amino resin, and the initial gloss (60 ℃) of the formed coating film is as low as 10 to 15. However, the extinction performance of the acrylic acid anode electrophoretic coating produced by domestic enterprises is still poor, so that the acrylic acid anode electrophoretic coating which has better extinction performance and good appearance hand feeling, mechanical property and corrosion resistance is needed to be developed.

Disclosure of Invention

Compared with the traditional acrylic acid anode electrophoretic coating, an anode electrophoretic coating formed by the coating composition has better extinction effect, smooth appearance, smooth hand feeling, high hardness, good adherence, and good boiling water resistance, acid resistance, alkali resistance, organic solvent resistance and impact resistance.

To achieve the above object, the present invention provides a coating composition comprising a vinyl copolymer which is a vinyl copolymer of ethylenically unsaturated monomers, wherein the ethylenically unsaturated monomers include an ethylenically unsaturated carboxylic acid monomer, a hydroxyl group-containing ethylenically unsaturated monomer, and a vinyl copolymer of an ethylenically unsaturated monomer containing a phosphoric acid group, and an amino resin.

Preferably, the weight of the ethylenically unsaturated carboxylic acid monomer is 1-20% of the weight of the vinyl copolymer, the weight of the hydroxyl-containing ethylenically unsaturated monomer is 05-30% of the weight of the vinyl copolymer, and the weight of the phosphoric acid group-containing ethylenically unsaturated monomer is 0.05-20% of the weight of the vinyl copolymer.

Preferably, the ethylenically unsaturated monomer further comprises an acrylate monomer. Preferably, the weight of the acrylate monomer is 30 to 80%, more preferably 35 to 60%, and even more preferably 40 to 55% of the weight of the vinyl copolymer.

Preferably, the ethylenically unsaturated monomers further comprise styrenic monomers. Preferably, the weight of the styrenic monomer is 1 to 20%, more preferably 3 to 15%, and still more preferably 5 to 10% of the weight of the vinyl copolymer.

Preferably, the structure of the phosphorus acid group-containing ethylenically unsaturated monomer is shown as formula (1),

wherein m is 1 or 2, and m + n is 3.

Preferably, the weight ratio of the vinyl copolymer to the amino resin is 1: 3-3: 1.

Preferably, the coating composition further comprises a solvent; in the coating composition, the weight fraction of the vinyl copolymer is 20-60%, the weight fraction of the amino resin is 20-60%, and the weight fraction of the solvent is 10-50%.

Preferably, the solvent is at least one of hydrocarbon, alcohol, ketone, ether, alcohol ether, nitrile, sulfoxide, and amide, and more preferably at least two; the amino resin is at least one selected from the group consisting of a fully alkyl methyl/butyl mixed etherified melamine resin, a hydroxymethyl methyl/butyl mixed etherified melamine resin, an imino methyl/butyl mixed etherified melamine resin, a fully alkyl methylated melamine resin and an imino methylated melamine resin.

In a second aspect, the present invention provides a use of the coating composition, specifically: it is used for anodic electrophoretic coating to produce a matte coating film.

In a third aspect, the invention also provides a matt coating film prepared from the coating composition.

Compared with the prior art, the invention has the beneficial effects that:

1. compared with the traditional acrylic coating, the coating composition comprises the vinyl copolymer and the amino resin (particularly the mixed etherified melamine resin), and the formed anodic electrophoretic extinction coating has better extinction property, smoothness and coating hardness, smooth hand feeling, good adhesion, and good boiling water resistance, acid resistance, alkali resistance, organic solvent resistance and impact resistance.

2. The coating composition of the present invention does not contain isocyanates, alkoxysilyl group-containing acrylic copolymers, silicon, particulate components, etc., and can achieve an excellent matting effect without the addition of a conventional matting agent.

Drawings

FIG. 1 is a photograph showing comparative films of coating films formed by different anodic electrodeposition coatings, (A) a coating composition of comparative example 1 (gloss (60 ℃ C.) of 25), (B) a coating composition of example 1 (gloss (60 ℃ C.) of 13, having transparency property);

FIG. 2 is a photograph showing a comparison of an uncoated substrate (shown as the upper part of the photograph and having a gloss (60 ℃ C.) of 166) and an anodized black substrate coated with the coating composition of example 2 by anodic electrodeposition to form a matte black coating (shown as the lower part of the photograph and having a gloss (60 ℃ C.) of 9).

Detailed Description

To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to specific examples. It will be understood by those skilled in the art that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the examples, the experimental methods used were all conventional methods unless otherwise specified, and the materials, reagents and the like used were commercially available without otherwise specified.

Herein, "vinyl copolymer" means a copolymer containing a vinyl group.

Herein, "ethylenically unsaturated monomer" is a generic name for monomer raw materials of the vinyl copolymer; if other limiting words are added to the "ethylenically unsaturated monomer", they refer to a certain monomeric starting material for the vinyl copolymer.

The present invention will be described in detail below.

1. Vinyl copolymer

The vinyl copolymer used in the present invention is formed by copolymerizing specific monomers, and preferably, the specific monomers are ethylenically unsaturated monomers including ethylenically unsaturated carboxylic acid monomers, hydroxyl group-containing ethylenically unsaturated monomers, and phosphoric acid group-containing ethylenically unsaturated monomers.

Preferably, the vinyl copolymer is acrylic acid phosphide, and the acrylic acid anode electrophoretic coating formed by combining the acrylic acid phosphide with amino resin through phosphating treatment has better extinction property, smoothness and coating hardness compared with the traditional acrylic acid anode electrophoretic coating, and has smooth hand feeling, good adherence, good boiling water resistance, acid resistance, alkali resistance, organic solvent resistance and good impact resistance.

The ethylenically unsaturated carboxylic acid monomer may be selected from at least one of acrylic acid, methacrylic acid, and the like, but the selectable type of ethylenically unsaturated carboxylic acid monomer is not limited thereto. In some preferred embodiments, the weight of ethylenically unsaturated carboxylic acid monomer is from 1 to 20%, more preferably from 3 to 15%, such as from 5 to 15% or from 3 to 10% of the weight of the vinyl copolymer.

The hydroxyl group-containing ethylenically unsaturated monomer may be selected from at least one of hydroxystyrene (hydroxyystyrene), hydroxyacrylic acid, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, trimethylolpropane di (meth) acrylate, ethoxylated trimethylolpropane di (meth) acrylate, propoxylated trimethylolpropane di (meth) acrylate, neopentyltetraol tri (meth) acrylate, dineopentylenetetraol penta (meth) acrylate, and the like, but the selectable type of the hydroxyl group-containing ethylenically unsaturated monomer is not limited thereto. In some preferred embodiments, the weight of the hydroxyl group-containing ethylenically unsaturated monomer is 5 to 30%, more preferably 10 to 25%, of the weight of the vinyl copolymer.

The above-mentioned ethylenically unsaturated monomer containing a phosphoric acid group may be selected from at least one of ethylene glycol methacrylate phosphate, polyethylene glycol methacrylate phosphate, propylene glycol methacrylate phosphate, polypropylene glycol methacrylate phosphate, butylene glycol methacrylate phosphate, polybutylene glycol methacrylate phosphate, and the like, but the kind of ethylenically unsaturated monomer containing a phosphoric acid group is not limited thereto. In some preferred embodiments, the weight of the phosphorus acid group containing ethylenically unsaturated monomer is from 0.05 to 20%, more preferably from 5 to 18%, of the weight of the vinyl copolymer.

In some preferred embodiments, the ethylenically unsaturated monomer containing a phosphoric acid group in the vinyl copolymer has a structure represented by formula (1),

wherein m is 1 or 2, and m + n is 3.

Optionally, the ethylenically unsaturated monomer may further comprise an acrylate-based monomer.

As used herein, the term "acrylate monomer" refers to acrylates and derivatives thereof. It is preferred to use acrylate monomers of low polarity, i.e. having an acid number between 0.1 and 2mg KOH/g. The low polarity acrylate monomer may be selected from the group consisting of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, 2-phenoxyethyl acrylate, 2- (2-ethoxyethoxy) ethyl acrylate, cyclic trimethylolpropane formal acrylate, isooctyl methacrylate, isodecyl acrylate, 2-ethylhexyl acrylate, ethoxylated 1, 6-hexanediol diacrylate, dipropylene glycol diacrylate, ethoxylated dipropylene glycol diacrylate, neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, 2-methyl-1, 3-propanediol diacrylate, ethoxylated 2-methyl-1, 3-propanediol diacrylate, 2-butyl-2-ethyl-1, 3-propanediol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, tris (2-hydroxyethyl) isocyanurate acrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, propoxylated pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, tripropylene glycol di (meth) acrylate, 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, propylene glycol tri (meth) acrylate, propylene glycol tetra (meth) acrylate, propylene glycol tetra (acrylate, and/or mixtures thereof, Ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated glycerol tri (meth) acrylate, triethylene glycol dimethacrylate or trimethylolpropane tri (meth) acrylate; it can also be selected from other commercially available products, such as those of Changxing materials industry (Guangdong) Co., Ltd

Or

Etc.; and may be selected from two or more of the above acrylate monomers. In some embodiments of the present invention, alkyl (meth) acrylates are used as acrylate monomers, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl acrylate, isooctyl (meth) acrylate, or any combination thereof. In some preferred embodiments, the weight of the acrylate monomer is 30 to 80%, more preferably 35 to 60%, and even more preferably 40 to 55% of the weight of the vinyl copolymer.

Optionally, the ethylenically unsaturated monomer may further comprise a styrenic monomer (styrene-based monomer).

Optionally, the ethylenically unsaturated monomer may further comprise a styrenic monomer and an acrylate monomer.

As used herein, the term "styrenic monomer" refers to styrene and its derivatives. The styrene monomer may be selected from the group consisting of styrene, 4-chloro-alpha-methylstyrene (4-chloro-alpha-methylstyrene), alpha-methylstyrene, 4-methylstyrene, alpha-ethylstyrene, 4-ethylstyrene, 3-methylstyrene, 4-propylstyrene, 4-cyclohexylstyrene, divinylbenzene, 3-methoxy-alpha-nitrostyrene (3-methoxy-alpha-nitrostyrene), nitrostyrene, fluorostyrene, bromostyrene, chlorostyrene, chloromethylstyrene, aminostyrene (aminostyrene), 4-methoxystyrene, 4-ethoxystyrene, acetoxystyrene (acetoxystyrene), 1-vinylnaphthalene (1-vinylnaphthalene), 2-vinylnaphthalene (2-vinylnaphthalene), 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene, and combinations thereof. It is preferable to use a low-polarity styrenic monomer, examples of which include: styrene, alpha-methylstyrene, 4-methylstyrene, alpha-ethylstyrene, 4-ethylstyrene, 3-methylstyrene, 4-propylstyrene, 4-dodecylstyrene, 4-methoxystyrene, 4-ethoxystyrene or a combination of any two or more thereof. According to one embodiment of the present invention, styrene is used as the styrenic monomer. In some preferred embodiments, the styrenic monomer is present in an amount of 1 to 20%, more preferably 3 to 15%, and even more preferably 5 to 10% by weight of the vinyl copolymer.

The vinyl copolymer of the present invention can be prepared by any known vinyl polymerization method in the art to which the present invention pertains.

2. Coating composition

The coating composition of the present invention comprises the above vinyl copolymer and amino resin, but does not contain isocyanates, acrylic copolymers having alkoxysilyl groups, silicon, particulate components, and the like. Therefore, the coating composition of the present invention can realize the function of a matting coating without containing a conventional matting agent component.

Preferably, the weight ratio of the vinyl copolymer to the amino resin is in the range of 1:3 to 3:1, such as 1:2.7, 1:2.5, 1:2.3, 1:2, 1:1.7, 1:1.5, 1:1.3, 1:1, 1.2:1, 1.5:1, 1.7:1, 2:1, 2.2:1, 2.5:1, 2.7:1, and the like.

The amino resin is a condensate of an amino compound such as melamine, urea, or benzoguanamine and an aldehyde compound such as formaldehyde or acetaldehyde, which is modified with a lower alcohol such as methanol, ethanol, propanol, or butanol. Specific examples of such amino resins include one or two or more kinds of fully alkyl methyl/butyl mixed etherified melamine resins, methylol methyl/butyl mixed etherified melamine resins, imino methyl/butyl mixed etherified melamine resins, fully alkyl methylated melamine resins, and imino methylated melamine resins. Preferably, the amino resin is the above-mentioned melamine resin containing mixed etherifications, for example: a fully alkyl methyl/butyl mixed etherified melamine resin, a methylol methyl/butyl mixed etherified melamine resin or an imino methyl/butyl mixed etherified melamine resin. More preferred is a fully alkyl methyl/butyl mixed etherified melamine resin (e.g., ETERMINO 9611-98 manufactured by Changxing materials industries, Guangdong) Co., Ltd.).

The amino resin of the curing agent is a condensation product of an amine or amide and an aldehyde. Examples of suitable amines or amides are melamine, benzoguanamine, urea and similar compounds. Typically, the aldehyde used is formaldehyde, but may also be selected from other aldehydes such as acetaldehyde and furfural. The condensation product contains methylol or similar hydroxyalkyl groups depending on the particular aldehyde used. Typically, the methylol group is etherified by reaction with an alcohol such as a monohydric alcohol containing one of 1 to 4 carbon atoms (e.g., methanol, ethanol, isopropanol, and n-butanol). The amino resins are available under the trademarks CYMEL from American Cyanamid and RESIMENE from Monsanto Chemical. The melamine-based compound (melamine) may be a commercially available product such as Cymel 202, Cymel 203, Cymel 254, Cymel 303, Cymel 325, Cymel 327, Cymel 328, Cymel 370, Cymel 380, Cymel 385, Cymel 1116, Cymel 1130, Cymel 1133, Cymel 1141, Cymel 1161, Cymel 1168 or Cymel 3020 manufactured by Cymite corporation; ETERMINO 9210 series, ETERMINO 9211 series, ETERMINO 9212 series, ETERMINO 9216 series, ETERMINO 9223 series, ETERMINO 9226 series, ETERMINO 9228 series, ETERMINO 9229 series, ETERMINO 9411 series (e.g., ETERMINO 9411-75), ETERMINO 9412 series (e.g., ETERMINO 9412-70), ETERMINO 9603 series (e.g., ETERMINO 9603-80), ETERMINO 9610 series (e.g., ETERMINO 9610-100), ETERMINO 9611 series (e.g., ETERMINO 9611-98), or a combination of two or more thereof, manufactured by Changxing materials industries (Guangdong) Co.

The coating composition typically also comprises a solvent. In general, the weight fraction of the vinyl copolymer in the coating composition is 20 to 60%, for example, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60% or the like; the amino resin is 20 to 60% by weight, for example, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, etc.; the weight fraction of the solvent is 10 to 50%, for example, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, etc.

The solvent may be selected from at least one of hydrocarbon, alcohol, ketone, ether, alcohol ether, nitrile, sulfoxide, and amide, but is not limited thereto. Wherein, the hydrocarbon can be one or more than two of n-hexane, cyclohexane, gasoline, kerosene, pine oil, etc., but the selection is not limited to the above; the alcohol can be selected from one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, 1, 2-butanediol, 1, 3-butanediol, 1, 4-butanediol, etc., but the selection is not limited thereto; the ether may be selected from, but is not limited to, ethyl ether; the alcohol ether can be one or more selected from ethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, etc., but the selection is not limited thereto; the nitrile may be selected from one or more of acetonitrile, phenylacetonitrile, etc., but the selection is not limited thereto; the sulfoxide can be selected from one or more of dimethyl sulfoxide, etc., but the selection is not limited thereto; the amide may be selected from one or more of N, N-dimethylformamide, dimethylacetamide, and the like, but the selection is not limited thereto.

According to a preferred embodiment of the present invention, the solvent is selected from at least two of hydrocarbons, alcohols, ketones, ethers, alcohol ethers, nitriles, sulfoxides, amides, and more preferably from at least two of alcohols, ethers, alcohol ethers. More preferably at least two of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, 1, 2-butanediol, 1, 3-butanediol, 1, 4-butanediol, methyl ether, diethyl ether, n-butyl ether, isobutyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol ethyl ether and propylene glycol butyl ether.

3. Use of coating compositions

The coating composition of the present invention can be used for preparing a matte coating film. Preferably, the matte coating film is prepared by means of anodic electrophoretic coating.

[ electrodeposition coating method ]

The electrodeposition coating obtained by the present invention is diluted with deionized water or deionized water containing a part of a hydrophilic solvent as necessary, and used for a matte or glossy type electrodeposition coating. When the electrodeposition coating is performed, the solid content concentration of the coating bath is preferably 4 to 20% by weight. If it is less than 4% by weight, it takes a long time to obtain the desired coating thickness, and if it exceeds 20% by weight, the state of the bath becomes unstable, and it is also a problem to be able to control the amount of coating taken out from the coating system.

As for the coating method, electrodeposition is performed using the object to be coated as an anode. The coating voltage is 30 to 350 volts, preferably 50 to 300V; the energizing time is 0.5 to 7 minutes, preferably 1 to 1.5 minutes. The higher the voltage, the shorter the energization time, whereas the lower the voltage, the longer the energization time. The coating voltage may be a method of applying the set voltage while applying the current, or a method of gradually increasing the set voltage. The electrodeposition object to be coated is washed with water if necessary, and then heated at 150 to 200 ℃ for 15 to 60 minutes to obtain a final coating film. The coating film thickness is preferably 5 to 30 μm. The material of the object to be coated by the electrodeposition coating method of the present invention is not particularly limited as long as it has conductivity, but a material of aluminum or an aluminum alloy is preferably used. In addition, the obtained coating film has excellent appearance such as smoothness and uniformity, and also has excellent properties such as mechanical properties, solvent resistance, chemical resistance and weather resistance.

Synthesis examples 1 to 3

Synthesis examples 1 to 3 each provide a method for preparing a resin, which specifically comprises: a reaction apparatus having a stirrer, a thermometer, a monomer dropping device and a reflux cooling device was prepared, and each raw material was weighed according to tables 1 and 2, and (A1) - (A8) and (E1) were uniformly mixed in advance, and (C) was added to the reaction apparatus, and the reflux temperature was raised to 90 ℃ with stirring, and the mixture of (A1) - (A8) and (E1) was dropped at 90 ℃ for 3.5 hours, and from the end of dropping, (E2) was added, and the reaction was continued at 120 ℃ for 2 hours, and finally, (B) and (D) were added to prepare a transparent viscous resin liquid having a solid content of 60% and an acid value of 36 mgKOH/g.

TABLE 1

TABLE 2

(Code)	Synthesis example 1	Synthesis example 2	Synthesis example 3
				A1	2 parts by weight of	2 parts by weight of	2 parts by weight of
A2	2 parts by weight of	4 parts by weight of	1 part by weight
				A3
	4 parts by weight of	6 parts by weight	12 parts by weight
				A4	6 parts by weight	8 parts by weight	5 parts by weight of
A5	8 parts by weight	10 parts by weight	8 parts by weight
				A6
	4 parts by weight of	4 parts by weight of	4 parts by weight of
				A7	4 parts by weight of	4 parts by weight of	4 parts by weight of
A8	6 parts by weight	0 part by weight	0 part by weight
				B	30 parts by weight of	30 parts by weight of	30 parts by weight of
C	10 parts by weight	10 parts by weight	10 parts by weight
				D	24 parts by weight	24 parts by weight	24 parts by weight
E1	0.7 parts by weight	0.7 parts by weight	0.7 parts by weight
				E2	0.2 part by weight	0.2 part by weight	0.2 part by weight
A/D value	1.5	1.58	1.5

In table 2, the a/D value is the weight ratio of the vinyl copolymer to the amino resin, i.e., a/D ═ (a1+ a2+ A3+ a4+ a5+ a6+ a7+ A8)/D.

Example 1

176.2 parts by weight of the resin solution obtained in synthesis example 1 was taken, heated to 80 ℃ and then 7.2 parts by weight of triethylamine was added, stirred for 30 minutes, 160.0 parts by weight of deionized water was added, and stirred for 2 hours to obtain a uniform electrodeposition coating liquid. Placing the coating liquid in an electrolytic bath, placing a required coating test piece on an anode, electroplating for 2 minutes under the voltage of 120V and the current of 800A, then placing the test piece for air drying, baking for 30 minutes at 180 ℃, cooling for one day, measuring the physical properties of a paint film, wherein the test results are shown in Table 3, and part of the test item methods are as follows:

film thickness: the Japanese KETT LH-373 eddy current film thickness meter is specially used for measuring the thickness of an insulating film on a nonmagnetic metal material such as aluminum alloy, magnesium alloy, zinc alloy, stainless steel, copper and the like. Meets the specifications of JIS K5600-1-7, JIS H8680-2, JIS H8501, ISO 2808, ISO 2360, ISO 2064, ISO 19840, BS 3900-C5, ASTM D7091-5 and ASTM E376.

Initial gloss of the coating film (60 °): the gloss was observed in the film at a light intensity of 60 ℃ as measured by UGV-5K (manufactured by Suga Test Instruments Co., Ltd.).

Boiling water resistance test: preparing a sealed groove, sealing the edge of the test piece by using an adhesive tape, putting the sealed groove into the groove, covering the test piece with water, starting heating, controlling the temperature to be 98 ℃, and maintaining for 12 hours;

and (3) testing acid resistance: preparing a closed groove, sealing the edge of the test piece with adhesive tape, placing 5 wt% (H) in the groove₂SO₄) Covering the test piece with the solution, and maintaining for 24 hours;

alkali resistance test: preparing a closed groove, sealing the edge of the test piece by using an adhesive tape, putting the sealed groove into the test piece, covering the test piece with 10 wt% (NaOH) solution, and maintaining for 24 hours;

impact resistance: 50cm, 1/4inch, load 1kg, ASTM D2794;

MEK resistance: wiping back and forth on the paint film using a wiper with a load of 1kg, ASTM D2486;

pencil hardness: a pencil was tested on the paint film using a hardness test pencil made by Mitsubishi paint, load 1kg, ASTM D3363-00;

adhesion: the paint film was tested using a Cross-cut method (Cross-cut) with 1mmx1mm per case and 3M #600 hundred cases of tape, ASTM D3359.

Comparative example 1

The same procedures as in example 1 were repeated except that the resin solution obtained in Synthesis example 1 was replaced with the resin solution obtained in Synthesis example 2, and the test results are shown in Table 3.

Comparative example 2

The same procedures as in example 1 were repeated except that the resin solution obtained in Synthesis example 1 was replaced with the resin solution obtained in Synthesis example 3, and the test results are shown in Table 3.

Example 2

176.2 parts by weight of the resin solution obtained in synthesis example 1 is taken, heated to 80 ℃, added with 7.2 parts by weight of triethylamine, stirred for 30 minutes, added with 20 parts by weight of aqueous black color paste, finally added with 160.0 parts by weight of deionized water, and stirred for 2 hours, thus obtaining the uniform electrodeposition coating liquid. The coating liquid is placed in an electrolytic bath, a required 6063S alloy plate test piece is placed on an anode, electroplating is carried out for 2 minutes under the voltage of 120V and the current of 800A, then the test piece is placed for air drying, the test piece is cooled for one day after being baked for 30 minutes at the temperature of 180 ℃, the gloss of a paint film is measured, the gloss (60 ℃) is 9, and the test result is shown in the lower part of a picture of figure 2.

TABLE 3

The comparative test piece appearance and gloss results of example 1 compared to comparative example 1 can be illustrated by fig. 1 and table 3.

The appearance and gloss results of the example 2 coating composition applied to a matte black coating film compared to the original untreated substrate coupon are illustrated in FIG. 2.

Compared with the comparative examples 1-2, the vinyl copolymer is subjected to phosphating treatment, and the obtained paint film has better flatting property, flatness and coating hardness, is excellent in acid resistance, alkali resistance, solvent resistance and impact resistance, and is suitable for application of the anodic electrophoretic paint.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A coating composition comprising a vinyl copolymer and an amino resin, said vinyl copolymer being a vinyl copolymer of ethylenically unsaturated monomers, wherein the ethylenically unsaturated monomers include ethylenically unsaturated carboxylic acid monomers, hydroxyl group-containing ethylenically unsaturated monomers, and phosphoric acid group-containing ethylenically unsaturated monomers.

2. The coating composition of claim 1, wherein the weight of said ethylenically unsaturated carboxylic acid monomer is from 1 to 20% of the weight of said vinyl copolymer, the weight of said hydroxyl group containing ethylenically unsaturated monomer is from 5 to 30% of the weight of said vinyl copolymer, and the weight of said phosphoric acid group containing ethylenically unsaturated monomer is from 0.05 to 20% of the weight of said vinyl copolymer.

3. The coating composition of claim 1, wherein the ethylenically unsaturated monomer further comprises an acrylate monomer; preferably, the weight of the acrylate monomer is 30-80% of the weight of the vinyl copolymer.

4. The coating composition of claim 3, wherein the ethylenically unsaturated monomers further comprise styrenic monomers; preferably, the weight of the styrenic monomer is 1-20% of the weight of the vinyl copolymer.

5. The coating composition of claim 1, wherein the ethylenically unsaturated monomer containing a phosphoric acid group has the structure of formula (1),

wherein m is 1 or 2, and m + n is 3.

6. The coating composition of claim 1, wherein the weight ratio of the vinyl copolymer to the amino resin is 1:3 to 3: 1.

7. The coating composition of any one of claims 1-6, further comprising a solvent; in the coating composition, the weight fraction of the vinyl copolymer is 20-60%, the weight fraction of the amino resin is 20-60%, and the weight fraction of the solvent is 10-50%.

8. The coating composition according to claim 7, wherein the solvent is at least one, preferably at least two, of a hydrocarbon, an alcohol, a ketone, an ether, an alcohol ether, a nitrile, a sulfoxide, an amide; the amino resin is at least one selected from the group consisting of a fully alkyl methyl/butyl mixed etherified melamine resin, a hydroxymethyl methyl/butyl mixed etherified melamine resin, an imino methyl/butyl mixed etherified melamine resin, a fully alkyl methylated melamine resin and an imino methylated melamine resin.

9. Use of a coating composition according to any one of claims 1 to 8 for anodic electrocoating to produce a matte coating film.

10. A matte coating film obtained from the coating composition according to any one of claims 1 to 8.