JPH0938568A - Method for forming cured coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a cured coating film with good coating face smoothness, solvent resistance and coating film hardness at ordinary tem. to 100 deg.C. SOLUTION: A coating in which carbonyl group-and carboxyl group-contg. resin or resin mixture is a binder or a resin or a resin mixture contg. carbonyl group and a group forming carboxyl group in the following process, namely, a process which brings it into contact with hydrazine compd. is a binder, is applied onto an object to be coat.ed to form an uncured coating film with carbonyl group and carboxyl group or carboxyl group-formable group. Thereafter, the uncured coating film is brought into contact with a hydrazine compd. to cure the coating film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for forming a coating film, which comprises coating the coating film with a crosslinking agent to cure the coating film.

[0002]

2. Description of the Related Art A coating film containing a thermoplastic resin as a binder has the property of becoming soft and tacky at high temperatures or becoming hard and brittle at low temperatures. Therefore, in order to maintain good physical properties from high temperature to low temperature, the coating film needs to be a cross-linked coating film. However, in order to cause a crosslinking reaction by heating, it is generally necessary to heat to a high temperature. In this case, if the heat capacity of the article to be coated is large, an enormous amount of heat is required, and in many cases, only about 1% of this amount of heat is used for the actual crosslinking reaction of the coating film. For this reason, it is preferable to use the room temperature crosslinking reaction from the viewpoint of effective use of energy, but generally, there is a problem that the crosslinking reaction at room temperature is slow and it is difficult to sufficiently proceed. Generally, if the method of accelerating the crosslinking reaction at room temperature is taken, the storage stability of the paint will be poor, and the usable life after the paint will be shortened.Because the leveling time of the applied coating will be short, the gloss will be low and the surface will be rough. It becomes a film. This drawback is noticeable especially when an organic solvent that dissolves a resin is not used like water-based paints and powder paints. For this improvement, a two-pack type paint is used. In this case, if the use is not completed within a short time after the paint formulation is completed, the viscosity of the paint increases,
Gelation occurs and it becomes unusable. In order to solve these problems, it is sufficient to first form a coating film that does not cause a crosslinking reaction and level it sufficiently, and then contact this coating film with a crosslinking agent to cure it. No method has been found that can form a practical cured coating film in combination with a crosslinking agent.

[0003]

Therefore, the present inventors have proposed a practical cured film which can be used as a paint having a long pot life and has good coating surface smoothness, solvent resistance and coating film hardness. The present invention has been completed as a result of intensive research on a method capable of forming at room temperature or a low temperature forced drying temperature up to about 100 ° C. That is, the present invention, a resin or resin mixture containing a carbonyl group and a carboxyl group or a coating material containing a resin or a resin mixture containing a carbonyl group and a carboxyl group-forming group as a binder is applied to an object to be coated to form an uncured coating film. The present invention provides a method for forming a cured coating film, which comprises contacting an uncured coating film with a hydrazine compound after the formation to cure the coating film.

The present invention provides "1. A coating material containing a resin or a resin mixture containing a carbonyl group and a carboxyl group as a binder, or a carbonyl group and a group which forms a carboxyl group in the subsequent step of contacting with a hydrazine compound. A coating material containing a resin or a resin mixture as a binder is applied to an object to be coated to form an uncured coating film having a carbonyl group, and a carboxyl group or a carboxyl group-forming group, and then the uncured coating film is converted to a hydrazine compound. A method for forming a cured coating film, which comprises contacting to cure the coating film 2. Cured coating according to item 1, wherein the binder is a resin containing a carbonyl group and a carboxyl group in one molecule. Method for forming film 3. The binder is a resin mixture of a carbonyl group-containing resin and a carboxyl group-containing resin, 1 4. The method for forming a cured coating film according to item 4. The method for forming a cured coating film according to item 1, wherein the binder is a resin containing a carbonyl group and a carboxyl group-forming group in one molecule. Is a resin mixture of a resin containing a carbonyl group and a resin containing a carboxyl group-forming group,
The method for forming a cured coating film according to item 1. 6. The method for forming a cured coating film according to item 1, wherein the binder resin and the resin mixture are a vinyl copolymer resin and a vinyl copolymer resin mixture. 7. Carbonyl group-containing vinyl monomer is 0.5 to 60% by weight in all monomers, and carboxyl group-containing vinyl monomer or carboxyl group-containing monomer is 0.5 to
The method for forming a cured coating film according to item 1, which is 60% by weight. 8. 7. The carboxyl group-forming group is a dialkylaminoalkyloxycarbonyl group (in any alkyl group, alkyl represents alkyl having 1 to 4 carbon atoms), and the carboxyl group-forming group is described in any one of 4 to 6 above. Method for forming cured coating film. 9. Formation of a cured coating film according to item 2, wherein the resin containing a carbonyl group and a carboxyl group in one molecule is a copolymer of a carbonyl group-containing vinyl monomer, a carboxyl group-containing vinyl monomer and another vinyl monomer Method. 10. The copolymer has a number average molecular weight of 500 to 2000,0.
The method for forming a cured coating film according to item 8 or 9, which is 00. 11. The method for forming a cured coating film according to item 3 or 5, wherein the carbonyl group-containing resin is a copolymer of a carbonyl group-containing vinyl monomer and another vinyl monomer. 12. The method for forming a cured coating film according to item 3, wherein the carboxyl group-containing resin is a copolymer of a carboxyl group-containing vinyl monomer and another vinyl monomer. 13. 13. The hydrazine compound is brought into contact with the coating film by immersing the uncured coating film on the coating object in an aqueous solution containing a hydrazine compound. The method for forming a cured coating film described in 1. 14． The method for forming a cured coating film according to item 9 or 11, wherein the carbonyl group-containing vinyl monomer is diacetone acrylamide. 15. 13. The method for forming a cured coating film according to any one of items 1 to 12, wherein the paint is a water-based paint. 16. The binder of the paint is a binder containing a carbonyl group- and carboxyl group-containing resin or a resin mixture and 70% by weight or less of another compatible resin.
The method for forming a cured coating film according to any one of items 1 to 13. 17． Item 16. The method for forming a cured coating film according to Item 15, wherein the article to be coated is electrically conductive, and the aqueous coating material is applied to the article to be coated by electrodeposition coating. 18. The method for forming a cured coating film according to any one of items 1 to 17, wherein the hydrazine compound is at least one selected from hydrazine and hydrazine hydrate. Regarding

The paint used in the present invention uses a resin or a resin mixture containing a carbonyl group and a carboxyl group or a carboxyl group-forming group in one molecule of the resin or a resin mixture as a binder. The resin or the resin mixture can be mentioned. (1) A resin having a carbonyl group and a carboxyl group in one resin molecule, (2) a resin mixture of a carbonyl group-containing resin and a carboxyl group-containing resin, (3) a carbonyl group and a carboxyl group-forming group in one resin molecule A resin having, (4) a resin mixture of a carbonyl group-containing resin and a resin having a carboxyl group-forming group, (5) a resin obtained by mixing two or more of the resins (1) to (4) or the resin mixture. blend.

The resin type of the above-mentioned resin or resin mixture is not particularly limited, and various resins such as vinyl copolymer resin, alkyd resin, polyester resin, epoxy resin and urethane can be mentioned. Among them, vinyl is preferable. Copolymer resins are preferred.

As a representative example of the carbonyl group-containing resin in the above (2) and (4), a carbonyl group-containing vinyl monomer [hereinafter, may be abbreviated as "monomer (a)". ] And a vinyl monomer other than the monomer (a).

Typical examples of the above-mentioned monomer (a) include acrolein, diacetone acrylamide, diacetone methacrylamide, formyl styrene, vinyl alkyl ketone having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl). Butyl ketone), diacetone acrylate, diacetone methacrylate, acetonitrile acrylate, β-acryloyloxyethyl acetyl acetate, δ-acryloyloxybutyl acetyl acetate, (meth) acryloyloxyalkylpropenal [the number of carbon atoms in the oxyalkyl group is 1 ~ 6], acetoacetoxyethyl acrylate, acetoacetoxyethyl methacrylate; compounds having 10 or less carbon atoms having a hydroxyl group and a carbonyl group (for example, 4-hydro). Xy-2-butanone, 3-hydroxy-3-methyl-2-butanone, 4-hydroxy-4
-Methyl-2-pentanone etc.) and a polymerizable unsaturated carboxylic acid (eg acrylic acid, methacrylic acid etc.); a hydroxyl group part of a compound having 10 or less carbon atoms having a hydroxyl group and a carbonyl group, and acrylamide or Condensation reaction product with amino group moiety of methacrylamide; compound having 10 or less carbon atoms having hydroxyl carbonyl group and polymerizable unsaturated monomer having isocyanate group (for example, m-isopropenyl-α, α-dimethylbenzyl isocyanate, Isocyanatoethyl methacrylate,
An adduct with methacryloyl acyl isocyanate, etc .; a compound having a hydroxyl group and a carbonyl group and having 10 or less carbon atoms and a diisocyanate compound (for example, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone) Diisocyanate,
A mono-adduct [having one isocyanate group] with 4,4′-methylenebiscyclohexyl isocyanate and the like is used as a hydroxyl group-containing polymerizable unsaturated monomer (for example, 2-
Examples thereof include monomers added to hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate and the like. These can be used alone or in combination of two or more.
Of these examples, acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl acrylate, acetoacetoxyethyl methacrylate, vinyl methyl ketone, and a polymerizable unsaturated monomer having an isocyanate group (for example, m-isoacetate) are preferable. Propenyl-α, α-dimethylbenzyl isocyanate, isocyanatoethyl methacrylate, methacryloylacyl isocyanate, etc.) and 4-
Examples thereof include an adduct with hydroxy-2-butanone, and diacetone acrylamide is particularly preferable.

As the other vinyl monomer which forms a copolymer with the carbonyl group-containing vinyl monomer, any monomer having copolymerizability with the carbonyl group-containing vinyl monomer can be used without limitation. As typical examples, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, butyl acrylate (n-, i-, t-), hexyl acrylate, 2-ethylhexyl acrylate, n-acrylate. Octyl, decyl acrylate, lauryl acrylate, stearyl acrylate, cyclohexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, butyl methacrylate (n-, i-, t-), Hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, decyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, and other acrylic acid or methacrylic acid having 1 to 3 carbon atoms.
An alkyl or cycloalkyl ester of 0;
Methoxybutyl acrylate, methoxybutyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate, ethoxybutyl acrylate, ethoxybutyl methacrylate, etc. Acrylic acid or methacrylic acid C2-C18 alkoxyalkyl ester; 2-hydroxy C2-C8 hydroxyalkyl esters of acrylic acid or methacrylic acid such as ethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate; vinyl acetate, vinyl propionate, Vinyl ester of fatty acid having 1 to 20 carbon atoms such as Veova monomer (vinyl ester of branched higher fatty acid manufactured by Ciel Chemical Co., Ltd.); ethylene, pro Ren, butylene, olefins such as pentene; butadiene, isoprene, diene compounds such as chloroprene; dimethylaminopropyl acrylamide, N- substituted such as dimethylaminopropyl methacrylamide (meth) acrylamide monomer; styrene,
Vinyltoluene, acrylamide, methacrylamide,
Acrylonitrile, methacrylonitrile, vinyl styrene chloride, vinylidene chloride, N-vinyl pyrrolidone, vinyl pyridine, vinyl pivalate, sodium sulfonate, etc .; acrylic acid, methacrylic acid, maleic anhydride, itaconic acid, etc. carboxyl group-containing monomers; dimethylaminoethyl N, N-dialkylaminoalkyl (meth) acrylates such as acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, dimethylaminopropyl acrylate, dimethylaminopropyl methacrylate, diethylaminopropyl acrylate, diethylaminopropyl methacrylate [each alkyl group The alkyl in is preferably an alkyl having 1 to 4 carbon atoms. ].

As a part of the above-mentioned other vinyl monomers, a carboxyl group-containing monomer [hereinafter, may be abbreviated as a monomer (b). ], It is possible to obtain the resin (1) having a carbonyl group and a carboxyl group in one molecule of the resin. As a part of the above-mentioned other vinyl monomers, N, N-dialkylaminoalkyl (meth) acrylate [hereinafter, may be abbreviated as a monomer (c). ], It is possible to obtain the resin (3) having a carbonyl group and a carboxyl group-forming group in one molecule of the resin. A dialkylaminoalkyloxycarbonyl group is introduced into the resin based on the monomer (c), and this group is easily hydrolyzed and converted into a carboxyl group when contacting with a hydrazine compound.

Typical examples of the carboxyl group-containing resin in the above (2) include a monomer (b) and a monomer (b).
Other than these, copolymers with other vinyl monomers can be mentioned. Examples of the other vinyl monomer other than the above monomer (b) include those exemplified as the other vinyl monomers other than the above monomer (a) to the monomer (b).
The monomer excluding can be exemplified.

A typical example of the resin containing a carboxyl group-forming group in the above (4) is a copolymer of the monomer (c) and another vinyl monomer other than the monomer (c). Examples of the vinyl monomer other than the monomer (c) include monomers obtained by removing the monomer (c) from those exemplified as the other vinyl monomers other than the monomer (a).

In the resin or resin mixture which is the binder component of the coating material used in the present invention, the amount of the carbonyl group-containing vinyl monomer in all the monomer components constituting the resin or resin mixture is from the viewpoint of crosslinkability and coating performance. It is suitable that the range is 0.5 to 60% by weight, more preferably 1 to 40% by weight, and further preferably 3 to 30% by weight. The amount of the carboxyl group-containing vinyl monomer or the carboxyl group-forming group-containing vinyl monomer in all the monomer components constituting the resin or resin mixture is 0.5 to 60 weight from the viewpoint of coating performance such as crosslinkability and water resistance. %, More preferably 1-40% by weight,
More preferably, the range is 3 to 30% by weight.

In the resin or resin mixture which is the binder component of the coating material used in the present invention, an anionic property can be imparted to the coating material by adding an anionic group such as a carboxyl group to the resin or resin mixture, thereby making the coating water-soluble or anionic. It becomes possible to impart the electrodeposition property. Further, by incorporating a cationic group such as an N, N-dialkylaminoalkyloxycarbonyl group based on N, N-dialkylaminoalkyl (meth) acrylate into the above-mentioned resin or resin mixture, it is possible to impart cationicity to the coating composition and And imparting cation electrodeposition property are possible. Among the other monomers, the water resistance of a coating film obtained by using an alkyl ester of acrylic acid or methacrylic acid having 12 to 30 carbon atoms in an amount of 5 to 50% by weight in all monomer components can be improved. . The above copolymer can be obtained by a known method such as emulsion polymerization, solution polymerization or bulk polymerization.

As the carbonyl group-containing resin in the resin mixture (2) or (4), other than the above copolymer,
Various resins containing a carbonyl group, for example, epoxy resin, alkyd resin, polyester resin, urethane resin and the like can be mentioned. These resins are, for example,
A compound having 10 or less carbon atoms having a hydroxyl group and a carbonyl group (for example, 4-hydroxy-2-butanone, 3-hydroxy-3-methyl-2-butanone, 4-hydroxy-4-methyl-2-pentanone) Diisocyanate compound (for example, tolylene diisocyanate, 4,
4'-diphenylmethane diisocyanate, xylylene diisocyanate, hixamethylene diisocyanate,
Mono-adduct [having one isocyanate group] with isophorone diisocyanate, 4,4′-methylenebiscyclohexyl isocyanate, etc. is used for various resins containing a hydroxyl group (for example, epoxy resin, alkyd resin,
Urethane resin, etc.). When various resins containing a hydroxyl group which react with the above-mentioned mono-adduct also have a carboxyl group, the above resin (1)
In addition, when various resins containing a hydroxyl group to be reacted with the above-mentioned mono-adduct also have a carboxyl group-forming group, the resin (3) can be used.

Examples of the carboxyl group-containing resin in the resin (2) include a grafted product of the carboxyl group-containing resin onto an epoxy resin, an addition product of maleic anhydride to an esterified product of an unsaturated fatty acid and an epoxy resin, and an epoxy resin. Addition product with polybasic acid, alkyd resin or polyester resin with residual carboxyl group, addition product of acid anhydride compound to hydroxyl group-containing resin such as alkyd resin or polyester resin, maleic anhydride to unsaturated fatty acid-modified alkyd resin And the dimethylolpropionic acid-polyvalent isocyanate compound, and the isocyanate group-containing urethane prepolymer and the hydroxyl group-containing carboxyl compound.

In the present invention, the form of the paint used is
It may be any of water-based paint, organic solvent type paint and powder paint, but when it is water-based, it has an ionic group in a hydrophilic organic solvent in addition to the resin obtained by emulsion polymerization. It is also possible to use a resin obtained by synthesizing a resin and neutralizing it, for example, a resin which is obtained by copolymerizing a monomer component containing an ionic monomer in a hydrophilic organic solvent and then water-dispersed or water-solubilized. When the ionic monomer is anionic, ammonia, amines,
By neutralizing with a base such as an alkali metal, and when the ionic monomer is cationic, formic acid,
It can be water-dispersed or water-soluble in an aqueous medium by neutralizing or quaternary salting with an acid such as acetic acid, propionic acid or lactic acid. The molecular weight of the copolymer is
There is no particular limitation, but generally, the number average molecular weight is 500 to
It is in the range of 2,000,000.

The coating material used in the method of the present invention contains a resin or a resin mixture containing a carbonyl group and a carboxyl group or a carboxyl group-forming group as a binder as described above, but it is necessary in addition to this resin or resin mixture. Accordingly, a resin having compatibility with the resin may be contained in the binder in an amount of 70% by weight or less. Examples of such resin include acrylic resin, vinyl resin, polyester resin, alkyd resin, epoxy resin, urethane resin, petroleum resin, cellulose derivative, and rosin. In addition, the coating used in the method of the present invention, if necessary, various additives that can be usually added to the coating, for example, color pigments, extender pigments, rust-preventive pigments, anti-sag agents, defoamers, and coating surface adjusters It may be a mixture of the above.

In the method of the present invention, after the above coating material is applied to an object to be coated, the uncured coating film on the object to be coated is brought into contact with a hydrazine compound to cure the film. Typical examples of the hydrazine compound include hydrazine, hydrazine hydrate (NH ₂ NH ₂ · H ₂ O), monomethylhydrazine, monoethylhydrazine, and the like. Among them, hydrazine and hydrazine hydrate are preferable. As a method of contacting the uncured coating film on the article to be coated with a hydrazine compound, a method of evaporating the hydrazine compound and bringing the uncured coating film into contact with the vapor, a hydrazine compound-containing liquid such as an aqueous solution of a hydrazine compound and an uncured coating film The method of contacting with a membrane can be mentioned. The hydrazine compound-containing liquid may be composed of only a hydrazine compound or may be an aqueous solution, and the concentration of the hydrazine compound is not particularly limited, but is generally 1% by weight.
It is suitable that the concentration is in the range of 5 to 90% by weight. The hydrazine compound aqueous solution may be composed of a hydrazine compound and water, but may contain an organic solvent and an acid component, if necessary.

[0020]

The steps of the method of the present invention will be described below. In the method of the present invention, the object to be coated with the coating material is not particularly limited, and metal, plastics, wood, paper, glass, ceramics, treated metal obtained by chemical conversion treatment of metal surface; Various things can be mentioned, such as a coated article formed by forming an undercoat coating film or an intermediate coating film.

As a method for coating the above-mentioned object to be coated with a coating containing a resin or a resin mixture containing a carbonyl group and a carboxyl group or a carboxyl group-forming group as a binder, dip coating, spray coating, roll coating, brush coating Etc. are used, and when the coating is water-based, electrodeposition coating can also be used. When performing electrodeposition coating, if the resin of the coating has a carboxyl group and is anionic, anion electrodeposition coating, if the resin has a cationic group such as a dialkylaminoalkyloxycarbonyl group If cationic, cationic electrodeposition coating is used.

After coating, the uncured coating film on the object to be coated is contacted with a hydrazine compound-containing liquid such as vapor of a hydrazine compound or an aqueous solution of a hydrazine compound, and the coating film is dissolved, dropped or excessively swelled by this contact. It is necessary not to cause the above, and after coating, the coating film is dried (normal temperature drying or forced drying) as necessary before the contact step with the hydrazine compound. By this drying, the solvent is removed from the water-based or organic solvent-based coating film, and the powder particles are fused to the powder coating film. Since no curing occurs before contact with the hydrazine compound, the coating film can be sufficiently fluidized and smoothed. Since the coating film applied by electrodeposition coating generally has a low solvent content, it is advantageous in many cases that this drying step can be omitted.

Examples of the method for bringing the uncured coating film on the article to be contacted with the hydrazine compound-containing solution include a method of immersing the solution in the solution, a method of spraying the solution, and a method of pouring the solution. Of these, the dipping method is preferable from the viewpoints of uniformity of contact with the liquid, difficulty in applying pressure to the liquid, easy process control, and the like. The contact between the hydrazine compound-containing liquid and the coating film is preferably performed until the hydrazine compound in the liquid can sufficiently penetrate into the coating film. This contact time (acidity, basicity, etc.), type of liquid (concentration, hydrazine compound type, solvent type, acidity, basicity), temperature, etc., but usually about 0.5 to 180 minutes is there. If the binder component of the uncured coating has a dialkylaminoalkyloxycarbonyl group, this group is hydrolyzed and converted into a carboxyl group in this contacting step. This hydrolysis suitably occurs by a dipping method using an aqueous solution containing a hydrazine compound. By contact between the uncured coating film on the article to be coated and the hydrazine compound, the hydrazine compound penetrates into the coating film to cause crosslinking. This cross-linking is considered to occur due to the reaction between the carbonyl group and the carboxyl group in the binder component of the uncured coating film and the hydrazine compound.

After the contacting step, if necessary, washing with water,
A cured coating film can be obtained by drying at room temperature or low temperature forced drying temperature of 15 ° C to 100 ° C. The heating can be performed as necessary for the purpose of further promoting the curing reaction to increase the degree of crosslinking. When this heating is carried out, it is preferably 100 ° C. or lower from the viewpoint of effective use of energy, but may be higher than 100 ° C.
It is performed under heating conditions of about 200 ° C. for about 1 to 40 minutes.
In this way, the desired crosslinked cured coating film can be obtained.

[0025]

The present invention will be described below in detail with reference to examples. Production of resins containing carbonyl and carboxyl groups

Production Example 1 Propylene glycol monomethyl ether 2 was added to a flask.
70 parts by weight was added and heated to 110 ° C., nitrogen gas was introduced into the flask to replace air. Next, the following monomer mixture liquid was dropped into the flask over 1.5 hours. Acrylic acid 42.5 parts by weight Diacetone acrylamide 180 parts by weight Styrene 270 parts by weight Stearyl methacrylate 270 parts by weight n-butyl methacrylate 270 parts by weight n-butyl acrylate 47.5 parts by weight Isobutyl methacrylate 270 parts by weight Perbutyl O (NOF CORPORATION) 2.7 parts by weight of the product was maintained at 110 ° C. for 1 hour, 2.7 parts by weight of perbutyl O was then added dropwise over 2 hours, and the mixture was aged at 110 ° C. for 2 hours. After the reaction, cool to 60 ° C,
After adding 695 parts by weight of isopropanol and neutralizing by adding 59.6 parts by weight of triethylamine, 1400 parts by weight of deionized water was further added and dispersed, and then distilled under reduced pressure to remove isopropanol, water and a part of propylene glycol monomethyl ether. Was removed to obtain Emulsion A.
Emulsion A has a solid content of 45.6% by weight and a pH of 8.
9, the particle size was 0.09 μm.

Production Example 2 Ethylene glycol monobutyl ether 18 was placed in a flask.
0 part by weight was added, and the mixture was heated to 120 ° C., and nitrogen gas was introduced into the flask to replace air. Next, the following monomer mixture liquid was dropped into the flask over 2 hours. Acrylic acid 15 parts by weight Diacetone acrylamide 90 parts by weight Styrene 80 parts by weight Methyl methacrylate 80 parts by weight Stearyl methacrylate 90 parts by weight n-Butyl acrylate 95 parts by weight Perbutyl O 9 parts by weight After completion of dropping, the mixture is kept at 120 ° C. for 2 hours, and then, 1.35
Part by weight of perbutyl O was added dropwise over 30 minutes. After a further 1 hour, 1.35 parts by weight of perbutyl O was added dropwise over 30 minutes and then aged at 120 ° C. for 2 hours. Then, the mixture was cooled to 60 ° C., 84 parts by weight of ethylene glycol monobutyl ether was added, and 12.6 parts by weight of triethylamine were further added to neutralize, followed by deionized water 2
100 parts by weight was added and dispersed to obtain a translucent resin aqueous solution B. The resin solution B has a solid content of 16% by weight and a pH of 8.
It was 7.

Production Example 3 Propylene glycol monomethyl ether 2 was added to a flask.
70 parts by weight was added and heated to 110 ° C., nitrogen gas was introduced into the flask to replace air. Next, the following monomer mixture liquid was dropped into the flask over 1.5 hours. Diacetone acrylamide 180 parts by weight Styrene 195 parts by weight n-butyl methacrylate 270 parts by weight n-butyl acrylate 360 parts by weight Isobutyl methacrylate 345 parts by weight Perbutyl O 2.7 parts by weight After completion of dropping, the mixture was kept at 110 ° C. for 2 hours and then 2 parts by weight. 0.7 parts by weight of perbutyl O was added dropwise over 2 hours. 2 more
It was aged at 110 ° C. for a time to obtain a resin solution C having a solid content of 83% by weight. In a separate flask, add 180 parts by weight of propylene glycol monomethyl ether, heat to 110 ° C.,
Nitrogen gas was introduced into the flask to replace air. Next, the following monomer mixture liquid was dropped into the flask over 2 hours. Acrylic acid 45 parts by weight Styrene 110 parts by weight Methyl methacrylate 110 parts by weight n-Butyl acrylate 185 parts by weight Perbutyl O 4.5 parts by weight After completion of dropping, the mixture is kept at 110 ° C. for 2 hours and then 1.3 parts by weight of perbutyl O. It dripped over 30 minutes. After 1 hour, 1.3 parts by weight of perbutyl O was added dropwise over 30 minutes, and then aged at 110 ° C. for 2 hours to obtain a solid content of 71%.
A wt% resin solution D was obtained. The obtained resin solution C and resin solution D were mixed so that the solid content weight ratio of C / D was 1/1, and propylene glycol monomethyl ether was further added to obtain a mixed resin solution E having a solid content of 40% by weight. Obtained.

Production Example 4 Ethylene glycol monobutyl ether 18 was placed in a flask.
0 part by weight was added, and the mixture was heated to 110 ° C., nitrogen gas was introduced into the flask to replace air. Next, the following monomer mixture liquid was dropped into the flask over 1.5 hours. N, N-dimethylaminoethyl methacrylate 27 parts by weight diacetone acrylamide 90 parts by weight styrene 82 parts by weight methyl methacrylate 82 parts by weight stearyl methacrylate 135 parts by weight n-butyl acrylate 34 parts by weight 2,2′-azobisisobutyronitrile 1 .35 parts by weight After the completion of dropping, the temperature was maintained at 110 ° C. for 2 hours, and then 1.35
Add 1 part by weight of Perbutyl O, and after an additional 1 hour, add 1.3
Add 5 parts by weight of Perbutyl O and hold for another 2 hours at 110 ° C.
Aged. Then, the mixture was cooled and propylene glycol monomethyl ether was added to obtain a resin solution F having a solid content of 40% by weight.

Examples 1 to 5 and Comparative Example 1 The emulsion A obtained in Production Example 1 was applied to a zinc phosphate-treated cold-rolled steel sheet using a No. 60 bar coater and then dried at room temperature for 1 day. After this coated plate was brought into contact with the hydrazine compound under the conditions shown in Table 1 using the crosslinking agent liquid shown in Table 1 below,
It was washed with water and dried at 80 ° C. for 10 minutes to obtain a cured coated plate. A coated plate obtained in the same manner as in Example 1 except that it was not brought into contact with the crosslinking agent liquid was set as Comparative Example 1.

Examples 6 to 9 and Comparative Example 2 The resin aqueous solution B obtained in Production Example 2 was used as an anion electrodeposition bath, and a zinc phosphate cold-rolled steel sheet was immersed in this, and an applied voltage of 10 was applied.
Anion electrodeposition coating was performed at 0 V for 3 minutes, followed by washing with water and drying at room temperature for 1 day. This coated plate was brought into contact with the hydrazine compound under the conditions shown in Table 2 using the crosslinking agent liquid shown in Table 2 below, then washed with water and dried at 100 ° C for 30 minutes to obtain a cured coated plate. Example 6 except that no contact was made with the crosslinker liquid
A coated plate obtained in the same manner as in Comparative Example 2 was used.

Examples 10 to 13 and Comparative Example 3 The mixed resin solution E obtained in Production Example 3 was applied to a zinc phosphate-treated cold rolled steel sheet using a No. 60 bar coater, and then dried at room temperature for 1 day. After this coated plate was brought into contact with the hydrazine compound under the conditions shown in Table 3 using the crosslinking agent liquid shown in Table 3 below,
It was washed with water and dried at 100 ° C. for 30 minutes to obtain a cured coated plate.
A coated plate obtained in the same manner as in Example 10 except that it was not brought into contact with the crosslinking agent liquid was set as Comparative Example 3.

Examples 14 to 15 and Comparative Example 4 The mixed resin solution F obtained in Production Example 4 was applied to a zinc phosphate-treated cold rolled steel sheet using a No. 60 bar coater and then dried at room temperature for 1 day. After this coated plate was brought into contact with the hydrazine compound under the conditions shown in Table 1 using the crosslinking agent liquid shown in Table 4 below,
It was washed with water and dried at 100 ° C. for 30 minutes to obtain a cured coated plate.
A coated plate obtained in the same manner as in Example 14 except that it was not contacted with the crosslinking agent liquid was set as Comparative Example 4. Various tests were performed on the cured coated plates obtained in Examples 1 to 15 and Comparative Examples 1 to 4 according to the following test methods. The test results are shown in Tables 1 to 4.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

[0037]

[Table 4]

Test Method Coloring of Coating Film: The coating film is visually observed to evaluate the degree of coloring. The case where no coloring is recognized is described as O.

Adhesion: Touch the coated surface with a finger to evaluate the degree of adhesion from the feeling. ⊚: No tackiness felt at all ◯: Slight tackiness felt △: Very tacky feel

Pencil hardness: JIS K5400 8.4.
2 (1990), the pencil scratching test is performed, and the coating film is evaluated for breakage. Erichsen value: JIS K5400 8.22 (199
0) According to the Erichsen value by the breaking distance method, a steel ball is extruded from the back surface of the Erichsen test piece using an Erichsen tester to measure the extrusion distance until cracks or peeling occur in the coating film. If there is no cracking or peeling even when extruded by 7 mm, it is displayed as 7 <.

Impact resistance: JIS K5400 8.3.
According to the 2 (1990) DuPont type impact resistance test, the test was performed by changing the drop height of the weight with the coated surface facing upward under the conditions of a falling weight of 500 g and a tip diameter of 1/2 inch. The maximum drop height that does not cause paint damage is displayed. 5
When the coating film is not damaged even at 0 cm, it is indicated as 50 <.

Solvent resistance: 2 drops of acetone (about 0.0
5 cc) is placed and left at room temperature to visually observe after the acetone has volatilized on the coated surface. ⊚: No change is observed (crosslinking reaches the surface of the article to be coated) ○: A small amount of wrinkles is observed (crosslinking does not reach the surface of the article to be coated, but is quite inside) Δ: Swelling once Traces remain on the entire surface of the dropped portion (crosslinking only on the coating film surface) x: Dissolution of the coating film is recognized.

Water resistance: The state of the coated surface after immersing the cured coated plate in deionized water is evaluated. ⊚: No abnormalities on the coated surface ○: Slight whitening on the coated surface Δ: Whitening on the entire coated surface, but no swelling ×: Whitening on the entire coated surface and swelling

In Tables 1 to 4 below, each symbol in the type of the crosslinking agent liquid has the following meaning. a: Aqueous solution having a concentration of 80% hydrazine hydrate b: Aqueous solution having a concentration of 16% hydrazine hydrate c: 8 parts by weight of acetic acid mixed with 100 parts by weight of an aqueous solution having a concentration of 16% hydrazine hydrate Aqueous solution.

In Tables 1 to 4, in the method of contact with the cross-linking agent liquid, "immersion" means "a method of immersing a coated plate in the cross-linking agent solution", and "steam" means "cross-linking agent". It means a method in which a coating plate is placed right above the liquid, about 1 cm away from the liquid surface, and vapor of the cross-linking agent liquid is applied to the coating surface. Tables 2-4
In each of Examples 6 to 15 and Comparative Examples 2 to 4 shown in FIG. 4, each test result is a result for a cured coated plate baked at 100 ° C. for 30 minutes. Instead of baking at 100 ° C. for 30 minutes, baking at 80 ° C. for 10 minutes is performed. When the cured coated plate was tested for solvent resistance, the same solvent resistance test results as those shown in Tables 2 to 4 were obtained.

[0046]

According to the method of the present invention, since an uncured coating film is formed and then the coating film is brought into contact with a hydrazine compound which is a curing agent to cure the coating composition, the coating composition used has good storage stability for a long period of time. The coating film has good smoothness because the coating film can be leveled sufficiently after coating, and the curing reaction of the coating film can be performed at room temperature or at a low temperature forced drying temperature up to about 100 ° C. In this temperature condition, it is possible to form a practical cured film having good solvent resistance and coating film hardness. In the method of the present invention, when the coating of the paint is carried out by electrodeposition coating, it can be applied to an article having a complicated shape, the coating efficiency is good, there are few problems in occupational hygiene, and the solvent in the uncured coating film is coated. Since the content can be reduced, it is advantageous in many cases that the drying step before contact with the aqueous solution as the curing agent can be omitted.

Claims (18)

[Claims] 1. A paint using a resin or a resin mixture containing a carbonyl group and a carboxyl group as a binder, or a resin or a resin mixture containing a carbonyl group and a group forming a carboxyl group in the subsequent step of contacting with a hydrazine compound. A coating material having a binder is applied to an object to be coated to form an uncured coating film having a carbonyl group and a carboxyl group or a carboxyl group-forming group, and then the uncured coating film is brought into contact with a hydrazine compound to form the coating. A method for forming a cured coating film, which comprises curing the film. 2. The method for forming a cured coating film according to claim 1, wherein the binder is a resin containing a carbonyl group and a carboxyl group in one molecule. 3. The binder is a resin mixture of a carbonyl group-containing resin and a carboxyl group-containing resin.
The method for forming a cured coating film described in 1. 4. The method for forming a cured coating film according to claim 1, wherein the binder is a resin containing a carbonyl group and a carboxyl group-forming group in one molecule. 5. The method for forming a cured coating film according to claim 1, wherein the binder is a resin mixture of a resin containing a carbonyl group and a resin containing a carboxyl group-forming group. 6. The method for forming a cured coating film according to claim 1, wherein the binder resin and the resin mixture are a vinyl copolymer resin and a vinyl copolymer resin mixture. 7. The carbonyl group-containing vinyl monomer is 0.5 to 60% by weight and the carboxyl group-containing vinyl monomer or the carboxyl group-containing monomer is 0.5 to 60% by weight in all the monomers. Of forming a cured coating film. 8. The carboxyl group-forming group is a dialkylaminoalkyloxycarbonyl group (in any alkyl group, alkyl represents alkyl having 1 to 4 carbon atoms). The method for forming a cured coating film described in the item. 9. The resin according to claim 2, wherein the resin containing a carbonyl group and a carboxyl group in one molecule is a carbonyl group-containing vinyl monomer, a carboxyl group-containing vinyl monomer and a copolymer with another vinyl monomer. Method for forming cured coating film. 10. The copolymer has a number average molecular weight of 500 to 20.
The method for forming a cured coating film according to claim 8 or 9, wherein the method is 100,000. 11. The method for forming a cured coating film according to claim 3, wherein the carbonyl group-containing resin is a copolymer of a carbonyl group-containing vinyl monomer and another vinyl monomer. 12. The method for forming a cured coating film according to claim 3, wherein the carboxyl group-containing resin is a copolymer of a carboxyl group-containing vinyl monomer and another vinyl monomer. 13. By immersing the uncured coating film on the article to be coated in an aqueous solution containing a hydrazine compound,
The method for forming a cured coating film according to claim 1, wherein the coating film is contacted with a hydrazine compound. 14. The carbonyl group-containing vinyl monomer is diacetone acrylamide.
The method for forming a cured coating film described in 1. 15. The method for forming a cured coating film according to claim 1, wherein the coating material is a water-based coating material. 16. The binder according to claim 1, wherein the binder of the coating material is a binder containing a carbonyl group- and carboxyl group-containing resin or a resin mixture and 70% by weight or less of another compatible resin. The method for forming a cured coating film described in 1. 17. The method for forming a cured coating film according to claim 15, wherein the article to be coated is electrically conductive, and the water-based paint is applied to the article to be coated by electrodeposition coating. 18. The method for forming a cured coating film according to claim 1, wherein the hydrazine compound is at least one selected from hydrazine and hydrazine hydrate.