JPS62288663A - Resin composition for coating compound having improved shelf stability and curing property - Google Patents

Abstract

PURPOSE:The titled composition suitable for coating various kinds of metals, slates, wood, etc., especially for topcoating in two coatings, containing an OH group-containing resin, an amino resin and a sulfonic group-containing resin. CONSTITUTION:The aimed composition containing (A) an OH group-containing resin (preferably blend of polyester resin having 200-15,000 number-average molecular weight, alkyd resin, urethane resin and vinyl resin having 500-30,000 number-average molecular weight), (B) an amino resin (preferably reaction product of triazine compound and aldehyde, melamine resin or alkyletherified melamine) and (C) a sulfonic group-containing resin (preferably compound having >=400mol.wt. or 4-sulfophthalic ester group-containing compound) as essential components.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a new and useful resin composition for coatings,
More specifically, it contains hydroxyl group-containing resins, amino resins, and sulfonic acid group-rich resins as essential paste resin components, that is, coating film-forming components. This invention relates to a resin composition that is particularly excellent in storage stability and curability, and can also be used as a paint for automobiles.

[Conventional technology]

Conventionally used resin compositions for coatings, which are made by blending a mixture of amino resins and hydroxyl group-containing resins with a sulfonic acid compound as a curing catalyst, can be used in cases where the amino resins have high curability. has a stability of 2,
On the other hand, if the stability is good, the curability is low.

In addition, when using a low molecular weight strong acidic catalyst such as sulfuric acid or p-toluenesulfonic acid, it is difficult to make the catalyst exist uniformly in an organic solvent-based coating resin composition, and it may cause damage to the coating film. It has the disadvantage of reducing performance such as corrosion resistance, alkali resistance, and water resistance.

[Problem that the invention seeks to solve]

The current situation is that, among these conventional resin Mi composites, no one has been found that satisfies the wide variety of conditions described below.

1) High storage stability; 11) Excellent curability; 111) Excellent coating film performance such as corrosion resistance, alkali resistance, and water resistance.

[Friendly means of solving problems]

However, in order to obtain a resin composition for paint that satisfies all of the above conditions at the same time, the inventors of the present invention have conducted intensive studies and have developed a method using sulfonic acid group-containing resins as the third film-forming component. Easy to use, has good storage stability,
The present invention was completed by discovering a resin composition that has excellent curability and also has excellent properties such as corrosion resistance, alkali resistance, and water resistance, and which provides a subsequent coating film.

That is, the present invention provides a coating material that has particularly excellent storage stability and curability, and which comprises (4) a hydroxyl group-containing resin, (B) an amino resin, and (C) a sulfonic acid group-containing resin as essential components. The purpose of the present invention is to provide a resin composition for

Here, the above-mentioned hydroxyl group-containing resins (4) refer to resins (4) having one or more, preferably two or more hydroxyl groups in the molecule, which can be uniformly dissolved and present in the target resin composition to be obtained. Polymers having a number average molecular weight (MN) that is necessary and sufficient for stably preserving the target resin composition and imparting sufficient performance to the resulting coating film. It is a synonym for certain resins,
Any material that satisfies these conditions can be used, but it is more preferable to use one that satisfies the following conditions.

That is, (1) a vinyl resin having a MN of 500 to 30,000 and a hydroxyl value (C)HV) of 30 to 250; (2) a vinyl resin having a M of 200 to 15,000; KatsuOH
At least one (condensation) polymer selected from the group consisting of alkyd resins, polyester resins, and urcitane resins, in which V is within the range of 20 to 600, or (condensation) polymers with the above vinyl resins (■) ■It is a mixture with.

Among them, in order to first prepare the vinyl resin (■), it is best to copolymerize a hydroxyl group-containing monomer and another monomer that can be copolymerized with it according to a conventional method, and then use such a hydroxyl group-containing monobase. Representative examples include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 3-hydroxybutyl (meth)acrylate. ) acrylate, 4-hydroxybutyl (meth)acrylate, 3-chloro-2
- hydroxyalkyl esters of (meth)acrylic acid, such as hydroxypropyl (meth)acrylate or polyethylene glycol mono(meth)acrylate;
Hydroxyalkyl ester monocardenic acids having unsaturated bonds such as adducts of acid anhydride group-containing monomers such as maleic anhydride or itaconic anhydride and glycols such as ethylene glycol; maleic acid or 7o/' unsaturated bond-containing dihydroxyalkyl esters of polycargenic acids such as fi/IJ hydroxyalkyl esters; or hydroxyethyl vinyl ether-1, E is h; b.

On the other hand, typical monomers copolymerizable with these hydroxyl group-containing monomers include methyl (meth)acrylate, ethyl (meth)acrylate, and n-butyl (meth)acrylate.
acrylate, 1so-butyl (meth)acrylate,
2-ethylhexyl (meth)acrylate, lauryl (
(meth)acrylate), N,N-dimethylaminoether (
meth)acrylate, N,N-diethylaminoethyl (
(meth)acrylic acid esters such as meth)acrylate or (β-methyl)glycidyl (meth)acrylate; (meth)acrylamide, N,N-dimethyl(
Amino group-containing monomers such as meth)acrylamide, N-methylol (meth)acrylamide or N-butoxymethyl (meth)acrylamide; carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid or (anhydrous)maleic acid. dimethyl itaconate, diethylma V) 4 L (tl'i C n-butyl fumarate, dialkyl esters of saturated dicarboxylic acids, vinyl acetate, vinyl benzoate or "Peova" (Netherlands Shell) Vinyl esters such as Visco 3F, 3FM, 8F or 8FM J (fluorine-containing (meth)acrylic esters manufactured by Osaka Organic Industry Co., Ltd.), nonololocyclohexyl ( 9-Fluoroalkyl group-containing vinyl esters such as N-1so-propyl-/4'-fluorooctanesulfonamide ether (meth)acrylate; ethylene or propylene; α-olefins such as vinyl chloride, vinyl fluoride, vinylidene chloride or vinylidene fluoride; vinylidene decadenide (vinylidene) such as styrene, α-methylstyrene, p-tart-butylstyrene, O-methylstyrene or aromatic vinyl monomers such as p-methylstyrene; acid anhydride group-containing monomers such as maleic anhydride or itaconic anhydride: p-styrenesulfonamide, N-methyl-p-styrenesulfonamide or N
, N-dimethyl-p-styrenesulfonamide,
Sulfonic acid amide group-containing monomers other than the above-mentioned nine carbamide group-containing monomers; N,N-dialkylaminoalkyl (meth)acrylates such as N,N-dimethylaminoether (meth)acrylate; adducts of compounds having both an active hydrogen group and a tertiary amino group that can react with an acid anhydride group such as N, N-trimethylaminopropylamino, and the above-mentioned acid anhydride group-containing monomers, etc. Tertiary amino group-containing monomers: cyanide group-containing monomers such as (meth)acrylonitrile; There are monomers having a phosphate ester bond.

When preparing the entire hydroxyl group-containing vinyl resin, the amount of hydroxyl group-containing monomers used varies depending on the molecular weight of the resulting vinyl resin, but is approximately 10 to 50% of the total monomer amount. It is appropriate that the remaining 90 to 50% by weight be selected from other copolymerizable monomers, and such copolymerizable monomers are ultimately The physical properties of the resulting cured coating should be determined while taking into consideration various factors such as pigment dispersibility.

To obtain the entire hydroxyl group-containing vinyl resin, solution polymerization method,
Although solution pressure polymerization, bulk polymerization, emulsion polymerization, and other known and commonly used methods such as suspension polymerization can be applied as they are, solution radical polymerization is the simplest method.

Typical solvents used in this process are hydrocarbons such as toluene, xylene, cyclohexane, n-hexane or octane; methanol, ethanol, 1so-zolopanol, n-butanol, 1ao-butanol, a. @e-Butanol 4L (H! Alcohol-based such as ethylene glycol monomethyl ether; Ester-based such as methyl acetate, ethyl acetate or n-butyl acetate; Acetone, methyl ethyl ketone, methyl-1a
A ketone type such as o-butylketone or cyclohexanone; or an amide type such as dimethylformamide or dimethylacetamide; these may be used alone or in combination with any of 2a or more.

Polymerization can be carried out by conventional methods using such solvents and various known and commonly used polymerization initiators such as azo-based or peroxide-based polymers. Various chain transfer agents such as lauryl mercaptan, octyl mercaptan, 2-mercaptoethanol or alpha-methylstyrene dimer can also be used as moderators. Particularly when using a hydroxyl group-containing chain transfer agent such as 2-mercaptoethanol.

Although it is possible to efficiently introduce hydroxyl groups into the fraction with a molecular weight below the average molecular weight in the resulting resin, it has the disadvantage of poor weather resistance, so it should be limited and used for the next purpose. It is.

Mayu, in addition to the above-mentioned solution radical polymerization method, there is an ionic polymerization method as a V@ manufacturing method for the hydroxyl group-containing vinyl resins, but the resins obtained by this ionic polymerization method also pose a problem in the present invention. Of course, it can be used without the

In the case of this ionic polymerization method, polymerization is carried out using an ionic polymerization initiator whose functional groups have been blocked in advance, and then the blocking agent present at the ends of the resulting resin is removed, resulting in a very fine molecular weight distribution. Narrow, and-
It is possible to obtain a resin that always has one or more functional groups in the molecule, and the ionic polymerization method itself is as disclosed in JP-A-58-13608.
It can be applied as is.

The glass transition point of the hydroxyl group-containing vinyl resin thus obtained is suitably within the range of -20°C to +50°C.

Next, the alkyd resins, polyester resins and/or urethane resins described above are all distinctive in that the raw material components JPMN and OHV are limited, and the esterification method etc. As the so-called synthesis conditions, well-known and commonly used means can be applied as they are.

Here, urethane resins include incyanate-modified acrylic resins, incyanate-modified alkyd resins, incyanate-modified polyester resins, etc.
It refers to resins having one or more urethane bonds in the molecule, but isocyanate-modified alkyd resins and / It is preferable to use polyester resin for the guide.

The urethane resin can be prepared by reacting an alkyd oligomer (or polyester oligomer) having one or more hydroxyl groups in the molecule with an organic diisocyanate compound, and then elongating the molecular chain.

Typical examples of such organic diisocyanate compounds include aliphatic diisocyanates such as hexamethylene diisocyanate or trimethylhexamethylene diisocyanate; cycloaliphatic diisocyanates such as xylylene diisocyanate or inphorone diisocyanate; or There are aromatic diisocyanates such as tolylene diisocyanate and 4,4'-diphenylmethane diisocyanate, and these can of course be used alone or in combination of two or more.
From the viewpoint of the weather resistance of the coating film, it is desirable to use aliphatic diisocyanates.

In addition, in order to synthesize the polyester component used in preparing the alkyd resins, polyester resins and/or urethane resins (■), terephthalic acid, isophthalic acid, orphthalic acid, 2,6-naphthalene dicargonic acid, etc. , 4.4'-Diphenyl radical acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, endomethylenetetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, maleic acid dicardic acids such as fumaric acid, itaconic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, pimelic acid, superric acid, sepacic acid or dimeric fatty acids (dimer acids), or trimellitic acid, trimesic acid, pyro Merit alcohol or polycarbonate/I/Z compounds such as cyclobentanetetracaldic acid, or their alkyl esters can be combined with polybasic acid components represented by reactive derivatives such as anhydrides. , on the other hand, ethylene glycol, propylene glycol, trimethylene glycol, 1.4-
alkylene glycols such as butanediol, 1,3-butanediol, 1,5-bentanediol, 1,6-hexanediol or neopentyl glycol;
Aromatic or alicyclic glycols such as 1,4-cyclohexane dimetatool, bis-hydroxyethyl terephthalate, hydrogenated bisphenol A, 4- or hydrogenated bisphenol A adduct with ethylene oxide; monoeoxy compounds such as phenylene oxide ; Or Gris Serif, ) IJ Me? Typical examples include tri- or higher polyols such as roll ethane, trimethylolpropane, pentaerythritol, dipentaerythritol or mannitol, or polyester polyols such as adducts of various glycol components such as dehydrated and ε-caprolactone. However, the polybasic acid component should be selected appropriately taking into consideration the physical properties of the coating film and economic efficiency, and the alcohol component should also be selected according to the required performance of the final cured coating film. It should be selected appropriately.

As a reminder, from the viewpoint of the weather resistance of the coating film, it is recommended to use neopentyl glycol in an amount of 30 mole or more in the total alcohol component, which may lead to better results.

Next, typical fatty acids used in preparing alkyd resins include octanoic acid (caprylic acid),
, lumitic acid, stearic acid.

Persatic acid, oleic acid, linoleic acid or lyluic acid, as well as coconut oil fatty acids, hydrogenated coconut oil fatty acids,
There are long chain saturated or unsaturated basic acids of C8 or higher, such as tall oil fatty acids, castor oil fatty acids, dehydrated castor oil fatty acids, rice bran oil fatty acids, linseed oil fatty acids, soybean oil fatty acids or safflower oil fatty acids, which are solvent-based. It should be selected appropriately, taking into consideration the solubility in the species, weather resistance of the coating film, economic efficiency, etc.

The polyester component used to prepare the alkyd resins, polyester resins and/or urethane resins (2) described above can be obtained using the various raw materials listed above, but in addition to the above, there are also polyester forming components. It is possible to use a polyester obtained by adding ε-caprolactone within a range of 40 to 90 molti to the total amount of all polybasic acid components and all alcohol components, respectively, and in such a case, A resin composition with excellent flexibility of a cured coating film can be obtained.

Thus, (1) the hydroxyl group-containing resins (Al) used in the present invention are obtained, but the alkyd resins, polyester resins, or urethane resins may be used alone or in combination of 281 or more, and the vinyl resins (2) and Of course, alkyd resins and polyester resins can also be used as a mixture with urethane resins, for example, when trying to obtain a target resin composition with good weather resistance. When trying to obtain a target resin composition with good flexibility, use alkyd resins and polyester resins/urethane resins. ② should be used more often.

Next, the above-mentioned amino resins (m includes triazine compounds such as melamine, benzoguanamine, acetoguanamine or guanylmelamine, and reaction products with known and commonly used aldehydes such as formaldehyde; among these, triazine-based It is preferable to use a reaction product of a compound and an aldehyde, preferably a melamine resin, particularly preferably a self-condensate of an alkyl etherified melamine resin such as hexamethoxymethylol melamine. .

Furthermore, the above-mentioned sulfonic acid group-containing resins (C) are:
- This refers to a compound having one or more sulfonic acid groups in the molecule or a mixture thereof, and the appropriate molecular weight of such compound is 400 or more, preferably 600 or more.

If the molecular weight is less than 400, the properties of the coating film such as corrosion resistance, alkali resistance, and water resistance will deteriorate.In particular, aromatic sulfonic group-containing compounds with a molecular weight of less than 400 will degrade the target resin. This is not preferred because there is an axial direction in which the composition will precipitate.

The sulfonic acid group-containing resin C) may be one in which the sulfonic acid group is introduced into vinyl resins, polyester resins, alkyd resins, or urethane resins, and such a simple synthesis method may be used. For example, a method of esterifying 4-sulfophthalanhydride [1 for the number of hydroxyl group-containing resins] and then adding erythrium to the resin is mentioned.

The content of sulfonic acid groups is 0.005 to 1.0 damol #L in the resin solid content constituting the target resin composition.
/9-resin, preferably 0.01 to 0.5 ■wt*/l-
A range of resin is appropriate.

t' below 0,005 ■equivalent/I-resin! Curing acceleration becomes insufficient, and conversely, if it exceeds 1.0 Da*/I-resin, storage stability deteriorates, so either is not preferred.

Furthermore, the organic solvents that may be used in preparing the composition of the present invention include aliphatic hydrocarbons, aromatic hydrocarbons, and alicyclic hydrocarbons having a boiling point of 30 to 300°C. For threads, ester, alcohol, ketone, and ether threads, amide threads are preferable, among which aliphatic hydrocarbon threads include n-hexane, 1IIo-hexane, n-hebutane, Imo-heptane, n- Octane, 1
So-octane or n-decane, etc., aromatic hydrocarbons such as toluene, xylene, tetralin, ethylbenzene or 11o-propylbenzene, etc.
Examples of alicyclic hydrocarbons include cyclohexane, methylcyclohexane, and decalin; examples of esters include methyl acetate, ethyl acetate, 18G-propyl acetate,
fin-butyl acetate, amyl acetate, ethyl formate, acetic acid
n-butyl or n-butyl propionate, etc.
Examples of alcohols include methanol, ethanol, n-propanol, 1ao-delononol, n-butanol, 2-ethylhexanol, or ethylene glycol; examples of ketones include acetone, methyl ethyl ketone, methyl-1so-butyl lactone, and cyclohexanone. Representative examples of the ether type include 1so-propyl ether, dioxane, or tetrahydrofuran, and representative examples of the amide type include dimethylformamide, dimethylacetamide, and the like.

In addition, phenol, cresol, diethylene glycol, diethylene glycol mono-n-butyl ether, furfural, and the like can be used.

In addition, the resin composition of the present invention contains inorganic pigments/
Alternatively, organic pigments 1r may be included, such as powders or flakes of aluminum, copper or zinc; or inorganic pigments such as Bengara, titanium dioxide, clay or calcium carbonate.

On the other hand, organic pigments such as magenta are used for cyanine blue, cyanine green, and Handy Yellow, respectively, and the amount of the pigments used is 0.1 to 60% pwc.
A range of 7 is appropriate.

On the other hand, when the pigments are not used, the coating resin composition of the present invention can be used as a top coat, especially for two coats.

Furthermore, the resin composition of the present invention contains ultraviolet absorbers such as benzotriazole threads, hydroxybenzophenone threads, unsaturated nitrile threads, silicone threads, and fluorine threads (
Various additives such as a leveling agent such as a meth)acrylic acid ester polymer can also be blended.

The resin composition for paint of the present invention thus obtained can be used as a general paint for various materials such as ferrous or non-ferrous metals, slate roof tiles or wood, or various (semi-)products thereof, and can also be used as an automobile paint, especially for 2 Suitable for use as a top coat in coat painting.

〔Example〕

Next, the present invention will be explained in more detail with reference to Reference Examples, Examples, and Comparative Examples. In the following, all parts and parts are based on weight unless otherwise specified.

Reference Example 1 [Preparation example of hydroxyl group-containing resins (A)] Thermometer,
160 parts of xylene and 160 parts of n-butyl acetate were charged into a reactor equipped with a stirrer, a nitrogen inlet tube, and a reflux condenser, and the temperature was raised to 125°C in a nitrogen atmosphere. 1 part, n-butyl acrylate
80 parts of n-butyl methacrylate, 120 parts of 2-hydroxypropyl acrylate, 66 parts of 2-hydroxypropyl methacrylate and 6 parts of acrylic acid, and 80 parts of n-butanol.

12 parts of t@rt-butylno-oxyoctoate,
A mixture consisting of 1 part of rt-butyl oxide and 3 parts of azobisisobutyronitrile was added dropwise over 8 hours, and after the dropwise addition was completed, the mixture was kept at the same temperature for 15 hours to remove the non-volatile components. (NY) is 60, the Gardner color (G, C,) is 1 or less, and the OHV of the solid fraction of (A-1) is 109, 9.

Reference Example 2 (same as above) In a next reactor equipped with a stirring device, a thermometer, a nitrogen inlet pipe and a reaction product water distillation pipe, 195 parts of adipic acid and hexahydro anhydride corresponding to 63.9 molti of the total polybasic acid components were added. 364 parts of phthalic acid and 11 parts of trimethylolzoro-14
9 parts and 322 parts of neointyl glycol, which accounts for 77.6% of the total alcohol content, were mixed in a nitrogen atmosphere with 5 parts of
The temperature was gradually raised to 230°C over time and maintained at the same temperature until the acid value reached 11, and the OHV was 102 and the M
A polyester resin with N of 2.010 was obtained.

Next, this was cooled to below 100°C, and 22% of xylene was added.
A solution of polyester resin with 4 parts added to make W 80%. Hereinafter, this will be abbreviated as resin (A-2).

Reference Example 3 (same as above) In a reactor similar to Reference Example 2, 364 parts of hexahydro-7-talic anhydride, which corresponds to 69.7 molty of the total polybasic acid component containing the iso and s parts of adipic acid, and trimethylol were added. 87.8 parts of propane and 398 parts of neopentyl glycol, which corresponds to 85.4 mol of the total alcohol component, were charged and the temperature was gradually raised to 230°C over 5 hours in a nitrogen stream until the acid value Polyester resin was obtained by maintaining the same temperature until the ratio reached 10.

Next, it was cooled to -100°C, and 253°C of xylene was added.
．． After adding 4 parts of di-n-butyltin dilaurate and 0.1 part of di-n-butyltin dilaurate, the mixture was kept at 65°C, and at the same temperature, 109 parts of hexamethylene diisocyanate was gradually added dropwise over 2 hours while being careful not to generate heat. After completion of the dropwise addition, the solution was kept at 80° C. for 1 hour to obtain a solution of partially urethanized polyester resin. Hereinafter, this will be abbreviated as resin (A-3), and the W of this product is 80 qb, and the OHV of the resin solid content is 1.
25, and the MN was 1.320.

Reference Example 4 (same as above) In a reactor similar to Reference Example 2, 170 parts of adipic acid, 280 parts of hexahydrophthalic anhydride corresponding to 61.0 mole of the total polybasic acid component, and 187 parts of trimethylolpropane were added. Then, 159 parts of neobentyl glycol, which corresponds to 45.9 molt of the total alcohol component, and 157 parts of coconut oil fatty acid were added, and the temperature was gradually raised to 230°C over a period of 5 hours in a gas stream. The mixture was heated and maintained at the same temperature until the acid value reached 10 to obtain an alkyd resin.

Next, the mixture was cooled to below 100° C., and 232 parts of xylene was added to obtain a resin solution containing 80% of W. Hereinafter, this will be abbreviated as resin (A-4).

The solid content OHV of this product is 130, and 8 is 2.0.
It was 70.

Reference Example 5 (same as above) Into a reactor similar to Reference Example 1, 134 parts of trimethylolpropane, 684 parts of ε-caprolactone, and 0.04 parts of tetrabutyl titanate were charged, and the temperature was raised to 180°C. A lactone-modified polyester resin was obtained by maintaining the temperature for 10 hours. Hereinafter, this will be referred to as resin (A-5)ζ
For brevity, the IW of this product is 100%, and the temperature is 25℃.
The Gardner viscosity was X, the OHV was 206, and the MN was 820.

Reference Example 6 [Preparation example of sulfonic acid group-containing resins (C)] In a reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser, a 140 parts of an aromatic hydrocarbon mixture in the range of 160 to 180°C] and 68 parts of xylene were heated to 125°C in a nitrogen stream. 60 of methacrylate
252 parts of n-butyl acrylate, 72 parts of 2-hydroxyethyl methacrylate, 60 parts of t+ert-butylno-9-oxyoctoate and
A mixture consisting of 3 parts of rt-butylene and monooxide was added dropwise over 8 hours, and the temperature was kept at the same temperature for 15 minutes after the addition was completed.
A vinyl resin solution with y of 62.4%, G and C of 1 or less, and MN of 3,000 was obtained by holding for a period of time.

Next, 100 parts of a 50% cellosolve acetate solution of 4-sulfophthalic acid was added to 321 fF of this resin solution and maintained at 60°C for 4 hours to obtain the desired resins. Hereinafter, this will be abbreviated as resin (C-1), and the V of this material is 59.
．． 5%, and the acid value of the solid content is 98.3.

Examples 1 to 5 The resins (A-1) to (A-5) obtained in Reference Examples 1 to 5 and "Sumimar M-100CJ [
Hexamethoxymethyl melamine (NV=100%) manufactured by Kaito Kagaku Kogyo Co., Ltd. and Tomo resin (C-
1) and the above resin (A-1) as part of the organic solvents.
~ (A-5) and in the resin (C-1),
The pigment and/or curing catalyst are mixed in proportions as shown in Table 1 to form a paint, and then the paint is made from the above-mentioned organic solvents. The resin composition for paint of the present invention, that is, the paint solution, is prepared by adjusting the spray viscosity with a diluting thinner to be described later so that the solid content at the time of painting is as shown in the same table.

Next, each coating solution was applied to a mild steel plate with a thickness of 0.8 mm to a dry film thickness of about 35 IJm, set for 30 minutes, and then heated at 140°C for 30 minutes.
Baking was carried out for 6 minutes to obtain a cured coating film of 6 Ya.

The storage stability and curability of each of the paints obtained in this manner were evaluated, as well as the various physical properties of the cured coatings obtained in this way, and the nine evaluations are summarized in the same table.

In addition, as a diluting thinner, "Swazol 1000J"
Aromatic hydrocarbon mixture with a temperature of 160 to 180°C manufactured by Maruzen Oil Co., Ltd.] / “Aromatic hydrocarbon mixture with a temperature of 115 to 142°C manufactured by Exxon Chemical Co., Ltd.” / n-butanol/2-ethoxyethyl acetate=
Use a mixed solvent of 30/30/20/20 (quantity ratio).

Comparative Example 1 Process 2 When the use of sulfonic acid group-containing resins (C) was completely omitted (Comparative Example 1) and in place of sulfonic acid group-containing resins C), a low molecular weight sulfonic acid compound (p-toluenesulfone) was used. Regarding the case (Comparative Example 2) using
A control resin composition for coating, i.e., a coating solution, was prepared in the same manner as in steps 5 to 5, and then applied and set.
Baking was performed to obtain a control cured coating t0.The storage stability and curability of each of the thus obtained coatings were added, and various coating film physical properties were evaluated for each of the cured coatings thus obtained. They are summarized in Table 1.

〔Effect of the invention〕

As is clear from the results shown in Table 1, the resin composition for coatings of the present invention has good storage stability and excellent curability, and also has excellent coating properties such as corrosion resistance, alkali resistance, and water resistance. It can be seen that it has the advantage of being

Claims (1)

[Claims] 1. As essential components, (A) hydroxyl group-containing resins, (B
1.) A resin composition for a paint, which comprises an amino resin (C) and a sulfonic acid group-containing resin, and has particularly excellent storage stability and curability. 2. The above-mentioned hydroxyl group-containing resin (A) has a content of 500 to 30
The composition according to claim 1, which is a vinyl resin having a number average molecular weight of ,000. 3. The method according to claim 1, wherein the hydroxyl group-containing resin (A) is at least one resin selected from the group consisting of polyester resin, alkyd resin, and urethane resin. Composition. 4. The above-mentioned hydroxyl group-containing resin (A) is 200 to 15
2. The composition according to claim 1, wherein the composition is at least one resin selected from the group consisting of polyester resins, alkyd resins, and urethane resins having a number average molecular weight of ,000. 5. The above-mentioned hydroxyl group-containing resin (A) is 200 to 15
a polyester resin having a number average molecular weight of ,000;
Claim 1, characterized in that it is a mixture of at least one resin selected from the group consisting of alkyd resins and urethane resins and a vinyl resin having a number average molecular weight of 500 to 30,000. The composition described in. 6. The amino resin (B) described above is a reaction product of a triazine compound and an aldehyde,
A composition according to claim 1. 7. The composition according to claim 1, wherein the amino resin (B) is a melamine resin. 8. Claim 1, characterized in that the above-mentioned amino resin (B) is an alkyl etherified melamine.
The composition described in Section. 9. The sulfonic acid group-containing resin (C) described above has one or more sulfonic acid groups in one molecule and has a molecular weight of 40
The composition according to claim 1, characterized in that the composition is at least one kind of compound having a number of 0 or more. 10. The sulfonic acid group-containing resins (C) described above are 4-
The composition according to claim 1, characterized in that it is at least one compound containing a sulfophthalic acid ester group.