JPS584590B2 - Film formation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a film, and more specifically, to a method of forming a film, and more specifically, a method of applying a hydrophilic non-aqueous emulsion type colored paint composition as a base coat, and applying a thermosetting water-based emulsion type paint composition as a top coat thereon. This invention relates to a method for forming a film using a two-coat, one-bake method for so-called hydrophilic non-aqueous emulsion paints and aqueous emulsion paints, which is characterized by applying a composition in a transparent state and then heating and curing a base coat and a top coat at the same time. .

Conventionally, it has been discovered that the 2-coat, 1-bake (hereinafter referred to as 2C-IB) system is superior to the 1-coat, 1-bake system in terms of gloss, chemical resistance, solvent resistance, outdoor weather resistance, etc. In fact, the 2C-1B method, which mainly uses thermosetting solution-type acrylic resin, is applied as a coating for finishing the exterior panels of automobile bodies and the like.

In recent years, the problem of pollution has become important in the paint field, and as one of the countermeasures against this problem, water-based emulsion type coating compositions have been developed from the aspect of reducing air pollution.

Naturally, therefore, a 2C-IB type coating system using this aqueous emulsion type composition can be considered.

However, in the case of 2C-IB coating systems, aqueous mainly emulsion type compositions are generally not suitable as base coats due to their characteristics (evaporation is slow due to the use of water;
(There are problems with painting workability such as poor retention of pigments), but on the other hand, it is preferable as a top coat due to its good gloss and finish.

However, when an aqueous emulsion-type composition is used as a top coat, the conventional method of using a solution-type acrylic resin composition as a base coat causes a repellency phenomenon of TOTSUBU COAT due to poor wetting between the top coat and the base coat, and This has been a major obstacle in applying emulsion type compositions to 2C-IB coating systems.

This is because the dispersion medium of aqueous emulsion-type compositions is generally water (although it may contain some organic liquid), and a highly polar dispersion stabilizer is used to stabilize the dispersion. The polarity of the emulsion type composition becomes extremely high, creating a difference in surface tension between it and the base coat surface, resulting in a repelling phenomenon.

As mentioned above, when an aqueous emulsion type composition is used as a base coat, since water is used as a dispersion medium, evaporation is slow and metal pigments are difficult to retain. When a top coat is applied, re-dispersion occurs, uneven recovery occurs, and the gloss of the paint film deteriorates, making it impossible to obtain a satisfactory paint film.

As a result of extensive research, we have found that by using a coating composition mainly consisting of a hydrophilic non-aqueous emulsion for the base coat and an aqueous emulsion-type coating composition for the top coat, we have succeeded in achieving all of these in the 2C-IB system. The problem was solved.

That is, the present invention involves coating a base material with a thermosetting hydrophilic non-hydraulic emulsion-type colored coating composition containing a hydrophilic organic liquid as the main dispersion medium, and then applying a thermosetting transparent aqueous emulsion-type composition. The present invention relates to a method for forming a coating film, which comprises applying a coating composition and then simultaneously curing the colored coating film and the transparent aqueous emulsion type coating film by heating.

Non-aqueous emulsions that use non-polar aliphatic hydrocarbons as the main dispersion medium are conventionally known, but the hydrophilic non-aqueous emulsions of the present invention use highly polar hydrophilic organic solvents as the main dispersion medium. This product holds the metal pigment well, has good coating workability such as no unevenness during spray painting, and is extremely suitable for base coat, and can also be used as a base coat when a water-based emulsion type composition is applied as Totsubu coat on top of it. Because of the high polarity of the base coat, the wetting condition is good, and since the base coat is a hydrophilic non-aqueous emulsion, it has good solvent volatility and excellent drying properties to the touch of oil, and there is no so-called uneven return due to blending with the top coat. Overall, the coating exhibits an extremely excellent finish.

Furthermore, since the hydrophilic non-aqueous emulsion composition is an engineered emulsion, it has a higher solids concentration during coating than conventional solution-type acrylic resin compositions, so less solvent is required to volatilize, and it can be applied as a tomb coat. Combined with an aqueous emulsion type composition, it is also advantageous in terms of reducing air pollution, and is an extremely excellent film swelling method.

The basic concept of the hydrophilic non-aqueous emulsion used as a base coat in the present invention is the same as that of conventional non-aqueous emulsions in which the main dispersion medium is an aliphatic hydrocarbon solvent.

That is, the vinyl monomer is polymerized in the presence of a dispersion stabilizer soluble in the organic liquid in an organic solution that dissolves the vinyl monomer but does not dissolve the polymer formed from the monomer, A stable dispersion of a vinyl polymer in which a polymer is dispersed in the organic liquid, and the organic liquid in the present invention has a solubility in water (number of grams dissolved in 100 g of water at 20°C).
is 5 or more, the number of hydrogen bonds is -19 to 0, and the solubility parameter (SP value) is 9 to 13.

Organic liquids having a solubility in water of 5 or more include methyl alcohol, ethyl alcohol, is
o-propyl alcohol, n-butyl alcohol, is
o-butyl alcohol, tert-butyl alcohol,
Alcohols such as tert-amyl alcohol, ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate, cellosolve butiacetate, carbitol acetate, methyl cellosolve acetate, methyl cellosolve, cellosolve, improvir cellosolve, butyl cellosolve, diethylene glycol These include ether alcohols such as monobutyl ether.

These can be used alone or in combination to increase the number of hydrogen bonds -
19 to 0, and those having a solubility parameter (SP value) of 9 to 13 can be used.

Of course, substances other than those listed above can also be combined with one or more of the substances listed above, and the mixture has the following properties in each of the three items of solubility, number of hydrogen bonds, and solubility parameter (SP value). It can be used if it satisfies the following range.

Number of hydrogen bonds, SP value (solubility parameter) of organic liquid
was calculated based on the following literature.

Solution theory and the c
computer-effect-ive tools
for the coating chemistR
C Nelson etag (Shell De
development Company ) J Paint Technology 42 A5 5 0
6 4 4 -652 ('70) Representative examples are listed below.

The numbers in parentheses are the density (25°C, g/ml), SP value, and number of hydrogen bonds, in that order.

Alcohols Methyl alcohol (07861, 1450-1
980), ethyl alcohol (078461278,-
18BO), isopropyl alcohol (0.78041
144, -1670), sec-butyl alcohol (0
．． 8018, 11.08, -17.50) n-butyl alcohol (O.8053, 1160-1800), te
rt-Butyl alcohol (0.7975, 11.24-
17.90), octyl alcohol (0.8287,
10.15, -18.70) etc.

Ketones acetone (0.7846, 9.62.+12.50),
Methyl ethyl ketone (0.7992, 9.45+10.
50), methyl isobutyl ketone (0.7957,8
．． 58. +10.50) etc.

Esters ethyl acetate (0.8939.8.91, +8.40),
n-Butyl acetate (0.8757.8.69, +8.OO
), isobutyl acetate (0.8658.8.43.+8.
70), Cellosolve Acetate (0.9674.9.3
5. +10.10), carbitol acetate (1.0042
, 9.48, +10.50) etc.

Ether alcohols methyl cellosolve (0.9597.11.68.0.0
), Cellosolve (0.9247.10.71,0.0)
, isoprovil cellosolve (0.9059, 9.26,
0.

0), putyl cellosolve (0.8959.9.87.0
．． 0), diethylene glycol monobutyl ether (0)
．． 9475, 9.79.0.0) etc.

The number of hydrogen bonds in a mixed organic liquid is calculated using the following formula.

vi: Volume fraction νi: Number of hydrogen bonds (absolute value) The number of hydrogen bonds in parentheses above is ki including the sign.
is the value of νi.

The SP value of the mixed organic liquid is calculated using the following formula.

δM = SP value of mixed organic liquid ■i: Volume fraction δi: SP value The dispersion stabilizer has a solubility in water of 5 or more, a hydrogen bond number of 19 to 0, and an SP value of 9' to 13. It is a compound containing a component that is solvated by a hydrophilic organic liquid, and has a tolerance in the range measured using the solvent shown below (adding an organic liquid to 1 g of resin at 20°C and dissolving the resin, Furthermore, it is characterized by having the number of ml of the organic liquid required until the resin component is precipitated without being dissolved and the solution starts to become cloudy.

Ethyl alcohol tolerance: 1~∞ Cellosolve tolerance: ∞ Cellosolve Acetate Tolerance: Must not be ∞.

Examples of these dispersion stabilizers include acrylic resins, alkyd resins, polyesters, cellulose derivatives, and vinyl copolymers, and examples thereof include modified products of these and graft or block polymers of these and vinyl monomers.

In addition, amine resins can also be used as dispersion stabilizers, either alone or in combination with the above-mentioned dispersion stabilizers.

As an example, an acrylic resin-based one-dispersion stabilizer will be described in detail below.

That is, for example, 2-hydroxyethyl acrylate,
2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate (these are the first components of the dispersion stabilizer) alone A polymer or a copolymer of two or more, or a copolymer consisting of 20% by weight or more of a first component and 80% by weight or less of a vinyl monomer as a second component listed below, where the second component is, for example, acrylic. Acids, methacrylic acid and vinylpyrrolidone, acrylic esters, methacrylic esters (excluding the first component, such as methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl meccrylate, butyl methacrylenite, etc.); , styrene, vinyl esters of saturated carboxylic acids such as vinyl acetate and vinyl propionate, ethylene, vinyl chloride and acrylamide derivatives such as acrylamide, methacrylamide, crotonamide, N-methylolacrylamide and diacetone acrylamide, etc. is appropriate.

The dispersion stabilizer contains the above components with a solubility in water of 5 or more, a hydrogen bond number of -19 to 0, and an SP value of 9 to 13.
In a hydrophilic organic liquid having a value of It is obtained by polymerization using a peroxide polymerization initiator such as penzoyl peroxide or tert-butyl peroctoate.

Polymerization initiator turbidity is 0.5 per 100 parts by weight of monomer.
~10 parts by weight is preferred.

An active double bond may be introduced into the dispersion stabilizer, for example, a method of copolymerizing a monomer having a carboxyl group in the dispersion stabilizer and then adding glycidyl acrylate or glycidyl methacrylate. (Or conversely, glycidyl acrylate or glycidyl methacrylate having a glycidyl group may be copolymerized in the dispersion stabilizer, and then acrylic acid or methacrylic acid having a carboxyl group may be added thereto).

By introducing active double bonds into the dispersion stabilizer,
The dispersion stabilizer chemically bonds with the vinyl polymer that forms the dispersed particles, increasing the stability of the dispersion and also making it possible to improve the chemical and physical properties of the coating film obtained from the dispersion. .

The molecular weight of this dispersion stabilizer is preferably 11.0.
00 to 20,000.

If it is less than 1,000, the dispersion becomes unstable; if it is greater than 200,000, the dispersion becomes extremely viscous and loses its characteristics (high solids content, low viscosity).

The above is a detailed description of an example of a dispersion stabilizer, and of course the present invention is not limited to this dispersion stabilizer.

The main vinyl polymer forming the dispersed particles includes, for example, styrene, vinyltoluene, acrylic acid, methacrylic acid, acrylic acid alkyl ester (alkyl group C
nH2n+1n=1-18), methacrylic acid alkyl ester (alkyl group CnH2n+1n=1-18), acrylamide, methacrylamide, acrylonitrile,
methacrylonitrile, N-methylolacrylamide,
Alkyl etherified products of N-methylolacrylamide, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and other long chains of methacrylic acid or acrylic acid Examples include esters, vinyl acetate, and vinylpyridine.

The polymerization of the vinyl monomer that forms the dispersed particles has a solubility in water of 5 or more, and a hydrogen bond number of -19 to 0.
2,2'-azoisobutylnitrile, 2,2'-azobis(2,4-dimethylpareronitrile) in a hydrophilic organic liquid with an SP value of 9 to 13 in the presence of a dispersion stabilizer. This is carried out using an azo polymerization initiator such as, peroxide polymerization initiator such as lauryl peroxide, penzoyl peroxide, tert-butyl peroctoate.

Polymerization initiator concentration is 0 per 100 parts by weight of vinyl monomer.
．． 5 to 10 parts by weight is preferred.

In this case, the amount of the dispersion stabilizer is 3 to 70% by weight of the total amount of the vinyl monomer and the dispersion stabilizer (both are solid content ratios).

If it is less than 3% by weight, a stable dispersion cannot be produced, and if it is more than 70% by weight, the dispersion becomes a solution and loses its characteristics (high solid content, low viscosity).

The total concentration of the vinyl monomer and dispersion stabilizer in the dispersion is usually 30 to 70% by weight.

The reaction temperature is about 60-160°C.

A hydrophilic organic liquid (dispersion medium) having a solubility in water of 5 or more, a hydrogen bond number of -19 to 0, and an SP value of 9 to 13 and a dispersion stabilizer are placed in a reaction vessel, and the total amount of vinyl monomer is added. It is also possible to prepare a polymerization initiator and react for 1 to 15 hours to obtain a stable dispersion, but it is also possible to obtain a stable dispersion liquid using vinyl monomer (the dispersion stabilizer may be mixed in whole or in part with the vinyl monomer). It is also possible to obtain a stable dispersion by dropping a mixture of the polymerization initiator and the polymerization initiator into a previously heated hydrophilic organic liquid for 1 to 7 hours, and then continuing the reaction for 2 to 7 hours.

A coloring agent, if necessary, a plasticizer, a coating surface conditioner, a hardening agent, etc. can also be mixed into this hydrophilic non-aqueous emulsion.

Coloring agents include dyes, organic pigments, inorganic pigments, and metal flakes such as aluminum.

There are known plasticizers, such as low molecular weight plasticizers such as dimethyl phthalate and dioctyl phthalate, and high molecular weight plasticizers such as vinyl polymer plasticizers and polyester plasticizers, which can also be used by being mixed into the dispersion. However, it is also possible to dissolve it in the vinyl monomer during the production of the dispersion and distribute it in the dispersed particles of the produced dispersion.

Curing agents include crosslinking agents such as amine resins, epoxy resins, and isocyanate-terminated compounds.

Typical amino resins include melamine and/or alkylated products of urea-formaldehyde condensates.

Furthermore, when making a paint, a highly stable enamel product can be obtained by first dispersing pigments, colorants, etc. with a pigment dispersant and then mixing them into a hydrophilic non-aqueous emulsion.

Of course, any conventionally known coating method may be used.

It is sufficient to wet the minute metal additives, such as aluminum flakes, with an organic liquid and mix them into the hydrophilic non-aqueous emulsion composition.

The aqueous emulsion type composition used as a top coat must satisfy various performances as a top coat, such as finish feel, gloss, durability, and chemical resistance.

Examples of aqueous emulsion type compositions include acrylic resins and polyester resins.

When creating an aqueous main emulsion type composition, the conventional synthetic method using a surfactant as a dispersion stabilizer, the self-emulsification method (once polymerized solution resin is mixed with amines etc.) There is a method of obtaining an emulsion by neutralizing the emulsion, adding water, and then distilling off the organic solvent used in the polymerization), and a method of synthesis using a high-molecular water-soluble polymer as a dispersion stabilizer.

When using an acrylic resin composition as an aqueous emulsion type composition, examples of vinyl monomers used in the synthesis of the acrylic resin include styrene, vinyltoluene, acrylic acid, methacrylic acid, acrylic acid alkyl ester (
Alkyl years old.

H2n+1n=1-18), methacrylic acid alkyl ester (alkyl group CnH2n+1n=1-18), acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, n-methylolacrylamide, n
- alkyl etherified product of methylol acrylamide,
2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate,
Examples include 2-hydroxypropyl methacrylate, other long chain esters of methacrylic acid or acrylic acid, vinyl acetate, vinylpyridine, and the like.

Generally known radical polymerization initiators are used for the polymerization of these vinyl monomers.

In addition, when using a polyester resin composition as an aqueous emulsion type composition, commonly known polyhydric alcohols, polybasic acids, and fatty acids are used as raw materials for the polyester resin, and known condensation methods such as bulk condensation method and solvent condensation method are used. After synthesis, an aqueous emulsion is obtained by the self-emulsification method (described above) or the like.

Although various methods can be used for the thermal crosslinking reaction of these aqueous emulsion type compositions, crosslinking using an amino resin is common.

In addition, when making a paint from the aqueous emulsion type composition used as Totsubu Coat, it is always acceptable to add dyes, pigments (color clear), and extender pigments to the extent that they do not cover the base coat, and other paint surface conditioners such as silicone. It is of course possible to add.

Furthermore, a water-soluble resin may also be added.

Examples of this water-soluble resin include acrylic resin and polyester resin.

When creating a water-soluble resin, hydrophilic groups (e.g.
There are methods such as adding a large amount of hydroxyl or carboxyl groups to make the resin solubilized in water, or making the resin solubilized by making the carboxyl groups in the resin into a neutralized salt form with an amine or the like.

In order to form an external finish coating, for example on an automobile body, by the method of the present invention, a hydrophilic non-aqueous emulsion colored paint is first applied to a primed substrate to a dry coating thickness of 5.
After spray painting to a thickness of ~40μ and setting for approximately 1 to 20 minutes, spray paint a water-based emulsion clear resin composition on top of this so that the dry coating thickness is 10 to 100μ. After setting for 20 minutes, set at a temperature of 100 to 180℃ for 15 to 60 minutes.
Baking is preferably performed at 140 to 180°C for 25 to 40 minutes.

If an amino resin is used as a crosslinking agent, the amount thereof is from 5 to 60% by weight, in particular from 25 to 60% by weight, based on the total amount of resin components including base enamel, top coat and amino resin.
40% by weight is preferable from the viewpoint of crosslinking density and coating performance.

The film thus obtained had excellent coating workability such as wetting, unevenness, and finished appearance, and also had good adhesion, solvent resistance, and acid resistance.

Next, the present invention will be specifically explained with reference to manufacturing examples and examples.

Both parts and percentages represent weight. Of course, the present invention is not limited in any way by these examples.

Production Example [A], Production of Hydrophilic Nonaqueous Emulsion for Baseute Production Example A-1 Synthesis of Dispersion Stabilizer (A) 70 parts of isobrobyl alcohol and 30 parts of cellosolve were refluxed, and the following monomers and polymerization initiator were added for 3 hours. The solution was added dropwise and aged for 2 hours after the addition.

2-hydroxyethyl acrylate 80 parts acrylic acid 5 parts styrene
15 parts 2.2'-Azobisisobutyronitrile 5 parts The obtained liquid was transparent, had a non-volatile content of 50, and had a Gardner viscosity (20° C.) of X.

Synthesis of dispersion A mixture of 100 parts isopropyl alcohol and 86 parts or more of dispersion stabilizer (A) was kept at the reflux temperature of isopropyl alcohol, and the following monomers and polymerization initiator were added dropwise over 5 hours, and aged for 2 hours after the dropwise addition. .

Acrylonitrile 88 parts 2-
Hydroxyethyl mekurylate 10 parts Methacrylic acid 2 parts 2.2'-Azobisisobutyronitrile 2 parts The obtained liquid was a milky white dispersion, and almost no sediment was observed even after it was left for 2 weeks. .

Non-volatile content is 50%, Gardner viscosity (25℃) is A to B
It showed very low viscosity.

Production Example A-2 Synthesis of Dispersion Stabilizer (B) The following stabilizer was kept at 80°C and glycidyl methacrylate (GMA) was added thereto to obtain a dispersion stabilizer (B) having an active double bond.

Dispersion stabilizer (A) 100 parts GMA 0.5 parts Paratertiary butylcatechol 0.01 parts Dimethylaminoethanol 0.03 parts Dispersion stabilizer (
B) was found to have 1-2 active double bonds per molecule.

The obtained liquid was a transparent liquid with a slight yellowish tinge, and the Gardner viscosity (25°C) was Y.

Synthesis of Dispersion Using this dispersion stabilizer (B), a dispersion was synthesized as follows.

Isopropyl alcohol 100 parts Dispersion stabilizer (B) 8 Maintain a mixture of 6 parts or more at the reflux temperature of isopropyl alcohol,
The following monomers and polymerization initiators were added dropwise over 5 hours, and aged for 2 hours after the addition.

Acrylonitrile 88 parts 2-Hydroxyethyl methacrylate 10 parts Methacrylic acid 2 parts 2.2'-Azobisisobutyronitrile 2 parts The obtained liquid was a milky white dispersion, and its room temperature storage stability was the same as Production Example A-1. It was even better than the obtained dispersion.

The nonvolatile content was 51%, and the Gardner viscosity (25°C) was 0 to P.

Production Example A-3 Synthesis of dispersion stabilizer (C) 60 parts of ethyl alcohol and 40 parts of cellosolve were refluxed, and the following monomers and polymerization initiator were added dropwise over 3 hours. ) was obtained.

2-Hydroxyethyl acrylate 50 parts Acrylic acid 5 parts Methyl methacrylate 20 parts Styrene
25 parts 2.2'-azobis(2,4-dimethylvaleronitrile) 1.25 parts The obtained liquid was transparent and had a Gardner viscosity (20° C.) of Z.

Synthesis of dispersion stabilizer (I) An active double bond is introduced into the dispersion stabilizer (C).

Dispersion stabilizer (C) 100 parts glycidyl methacrylate 0.7 parts para-tertiary butylcatechol o. o i part Dimethylaminoethanol 0.05 part or more is kept at 80°C until the molecular weight and acid value of the dispersion stabilizer (C) decrease until each molecule has one active double bond. The reaction was continued to obtain a dispersion stabilizer (D).

Synthesis of dispersion Ethyl alcohol 100 parts Dispersion stabilizer (C) 21.5 parts Dispersion stabilizer (D) Keep the mixture of 21.5 parts or more at the reflux temperature of ethyl alcohol, and add the following monomers and polymerization initiator over 5 hours. The solution was added dropwise and aged for 2 hours after the addition.

Acrylonitrile 35 parts Methyl methacrylate 30 parts Styrene
20 parts 2-hydroxyethyl methacrylate 10 parts methacrylic acid
5 parts 2.2'-Azobisisobutyronitrile 2 parts The obtained liquid was a milky white dispersion and had very good storage stability at room temperature.

The nonvolatile content was 50%, and the Gardner viscosity (25°C) was P to Q.

Production Example A-4 Synthesis of Dispersion Stabilizer (E) 60 parts of ethyl alcohol 40 parts of butyl cellosolve were refluxed, and the following monomers and polymerization initiator were added dropwise over 4 hours.
Time aging was performed.

2-hydroxyethyl acrylate 30 parts acrylic acid 7 parts methyl methacrylate 35 parts styrene
28 parts 2.2'-Azobis (
(2,4-Dimethylvaleronitrile) 25 parts The obtained liquid was transparent and had a Gardner viscosity of V.

Synthesis of dispersion, ethyl alcohol 100 parts Dispersion stabilizer (E) 50 parts or more The mixture was kept at the reflux temperature of ethyl alcohol, the following monomers and polymerization initiator were added dropwise over 5 hours, and after the dropwise addition, the mixture was aged for 3 hours. I did it.

Acrylonitrile 20 parts Methacrytonitrile 5 parts Methyl methacrylate 40 parts Styrene
20 parts 2-hydroxyethyl methacrylate 10 parts methacrylic acid
5 parts 2,2'-azobisisobutyronitrile
The liquid obtained in 5 parts was a milky white dispersion and had good storage stability at room temperature.

The non-volatile content was 51% and the Gardner viscosity was DE.

Production Example A-5 Synthesis of dispersion Cellosolve 100 parts Dispersion stabilizer (E) A mixture of 50 parts or more was maintained at 80°C, and the following monomers and polymerization initiator were added to 5 parts.
The solution was added dropwise for 3 hours, and aged for 3 hours after the addition.

Acrylonitrile 25 parts Methyl methacrylate 30 parts Styrene
30 parts 2-hydroxyethyl methacrylate 10 parts methacrylic acid
5 parts 2,2'-azobisisobutyronitrile 5 parts The resulting liquid is a milky white dispersion with good storage stability at room temperature.

Gardner viscosity was R-S at 50% non-volatile content.

Production example A-6 Synthesis of dispersion stabilizer (F) Isopropyl alcohol 40 parts Cellosolve 60 parts or more was kept at reflux temperature, the following monomers and polymerization initiator were added dropwise over 4 hours, and after the dropwise addition it was aged for 3 hours and dispersed. A stabilizer (F) was obtained.

2-hydroxyethyl acrylate 40 parts acrylic acid 10 parts styrene
25 parts Methyl methacrylate 25 parts 2,2'-azobisisobutyronitrile 5 parts The obtained liquid was transparent, had a nonvolatile content of 50%, and had a Gardner viscosity (25°C) of T.

Synthesis of dispersion a-Butyl alcohol 30 parts Cellosolve 70 parts Dispersion stabilizer (F)
A mixture of 36 parts or more was kept at reflux temperature, and the following monomers and polymerization initiators were added dropwise over 5 hours, and aged for 4 hours after the addition.

Acrylonitrile 30 parts Methyl methacrylate 35 parts Ethyl acrylate 10 parts Styrene
25 parts 2 parts 2,2'-azobisisobutyronitrile The resulting liquid was a milky white dispersion, and had very good storage stability at room temperature.

The nonvolatile content was 50%, and the Gardner viscosity (25°C) was B.

Production Example A-7 1 Synthesis of dispersion stabilizer (G) Ethyl alcohol 50 parts Cellosolve 50 parts or more was kept at reflux temperature, the following monomers and polymerization initiator were added dropwise over 5 hours, and aged for 4 hours after the dropwise addition.

2-Hydroxyethyl acrylate 50 parts Methyl meccrylate 20 parts Styrene 30 parts 2,2'-azobisisobutyronitrile 5 parts The resulting liquid was transparent, had a non-volatile content of 50%, and had a Gardner viscosity (at 25°C) of R.
-It was S.

Synthesis of dispersion Ethyl alcohol 1 50 parts Cellosolve 50 parts Dispersion stabilizer (G)
Keep at least 200 parts at reflux temperature and add the following monomers, polymerization initiator, and chain transfer regulator.

Acrylonitrile 30 parts Methacrylonitrile 10 parts Methyl methacrylate 20 parts Styrene
20 parts 2-hydroxyethyl methacrylate 10 parts methacrylic acid
10 parts 2,2'-abbisisobutyronitrile
1 part 1-octanethiol 0.1
The obtained liquid was a milky white dispersion, had excellent storage stability at room temperature, had a non-volatile content of 50%, and had a Gardner viscosity (25° C.) of MN.

Production Example [B] Production of aqueous emulsion for top clear Production Example B-1 Deionized water 103 parts Neogen R (manufactured by Daiichi Kogyo Seiyaku ■) 3.3 parts 60
% sodium dodecylbenzenesulfonate is charged into a reaction vessel, nitrogen is introduced and air is removed from the reaction system, and the mixture is stirred and heated to raise the temperature to 80°C.

Styrene is added to this aqueous solution.
20 parts butyl acrylate 50 parts, methyl methacrylate 28 parts 2
-Hydroxymethyl methacrylate 8 parts Acrylic acid 2 parts N-dodecylmercabutane 1 part A mixed solution and 1 part of ammonium persulfate dissolved in 10 parts of deionized water were added dropwise from separate ports over 3 hours to effect polymerization.

After the addition was completed, heating was continued for another 2 hours to obtain a milky white emulsion with a solid content of 47% and a viscosity of 110 centivoids.

Production example B-2 Styrene 30 parts Butyl methacrylate 50 parts 2-hydroxyethyl acrylate 10 parts Acrylamide
5 parts acrylic acid
A mixture of 5 parts 2.2'-azobisisobutyronitrile and 0.5 parts was added dropwise to ethanol heated under reflux in a reaction vessel, and polymerization was carried out over 5 hours, followed by equivalent neutralization with diethanolamine. Add 186 parts deionized water.

Ethanol was distilled off under reduced pressure (50°C) from this aqueous solution to obtain a milky white emulsion with a solid content of 35% and a viscosity of 320 centipoise.

Production example B-3 2-hydroxyethyl methacrylate 5 parts acrylic acid 20 parts styrene
A mixture of 40 parts ethyl methacrylate 35 parts 2,2'-azobisisobutyronitrile 1 part was added dropwise into 100 parts of cellosolve heated to 120°C in a reaction vessel,
After polymerization for 7 hours, 70 parts of cellosolve was distilled off, neutralized with triethylamine, and deionized water was added to bring the nonvolatile content to 15%.

Add methyl methacrylate to 100 parts of this aqueous solution.
24 parts ethyl acrylate
15 parts N-butoxymethylacrylamide
18 parts 2-hydroxyethyl methacrylate
After adding 3 parts of ammonium persulfate and stirring for 1 hour, 1 part of ammonium persulfate was added.
1 part was dissolved in 5 parts of deionized water and heated at 75° C. for 4 hours to obtain an emulsion with a solids content of 45% and a viscosity of 130 centipoise.

Paint manufacturing Manufacture of enamel paints for base coats Table 1 shows manufacturing examples of base coat enamel paints.

As for the manufacturing method, except for Base-6, the colorant was first well dispersed in the amine resin by boiling the paint, and then the hydrophilic non-aqueous dispersion was gradually mixed into the colorant-dispersed amino resin while stirring well.

Base-6 uses a dispersion stabilizer (F) as a pigment dispersant to disperse the colorant, and then mixes the amine resin with it.
Subsequently, the hydrophilic non-aqueous diversion was gradually mixed while stirring thoroughly.

The paint stock solution obtained in this way is then treated with thinner (cellosolve/isobrobyl alcohol/carbitol acetate = 50/40/10 weight ratio) to a viscosity of 13 to 10.
The solution was diluted to 16 seconds (food cup A4, 20°C).

*Poster Balm Brown (product name, manufactured by Hoechst Co., Ltd.) Production of paint for top clear The high solid content resin for top clear is made into a paint from the above production example B-
An amino resin is mixed with the resins obtained in Steps 1 to B-3, and further, although not necessarily required, the main production step. In the example, a hydrophilic organic solvent and/or a water-soluble resin were added to improve the coating condition, and then diluted with water to a viscosity of 30 to 35 seconds (Food cup A4, 20°C).

Table 2 shows manufacturing examples of top clear paints.

Note 1: Non-volatile content after heating and drying 2 g of paint at 150°C for 1 hour Note 2: Aroro 7557N (manufactured by Nissaku Arrow Chemical Co., Ltd.)
50% resin solution) Note 3 Monomer composition is styrene/
Butyl methacrylate/2-hydroxypropyl methacrylate/acrylic acid = 35/40/15/10 (weight ratio) Viscosity at solid content of 50 parts (25°C, Gardner tube) XY Examples 1 to 7 Examples 1 to 7 The coating conditions are shown in Table 3, and the finished coating film condition and film performance are summarized in Table 4.

The materials used for the coatings shown in Table 3 were coated on a bonded steel plate with an electrodeposition coating normally used for automobile coatings, and then baked, followed by an amino alkyd resin paint (also commonly used as an intermediate coating for automobiles). (used as)
I applied it by foot, baked it, and sanded it with sandpaper.

The coating booth temperature was 20° C., and the coating was done by hand using a spray gun at an air pressure of 5 kg/cm.

1-stage base coat means that the film is applied once in a row to achieve the specified film thickness, and 2-stage means that the base coat is applied once, then set for 2 minutes, and then the base coat is applied on top of that to achieve the specified film thickness. The film thickness was obtained.

After applying the base coat and setting everything for 3 minutes, I applied the top clear coat in one stage.

After that, I set it up for 10 minutes and then fired it.

Of course, this coating method is standardly employed in general 20-1B type automobile coating, and it goes without saying that this coating method does not limit the present invention.

Claims (1)

[Claims] 1. A thermosetting hydrophilic nonaqueous emulsion type colored coating composition containing a hydrophilic organic liquid as the main dispersion medium is coated on a base material, and then a thermosetting transparent aqueous emulsion type coating composition is applied. A method for forming a coating film, which comprises subsequently heating and curing the colored coating film and the transparent aqueous emulsion type coating film at the same time.