JPH0649844B2 - Resin composition for paint - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin composition for paint. More specifically, the present invention relates to a resin composition for paints, which is required to have excellent weather resistance and gloss, for example, for top coating on automobiles.

(Prior Art) Conventionally, in an automotive topcoating paint that is required to have excellent weather resistance, image clarity or gloss, an alkyd-melamine resin system is used for solid colors, and an acrylic-melamine resin is used for metallic colors. However, an acrylic lacquer type was mainly used for repair.

However, the coating film obtained from the above coating composition has a gloss retention of almost 8 in a long-term accelerated weathering test.
In many cases, it decreased to 0% or less.

By the way, in recent years, there has been a strong demand for coating compositions having more excellent weather resistance and gloss due to the trend toward higher quality products and differentiation.

Therefore, in order to obtain such a coating composition, it is necessary to improve the color developing agent (resin component) which is the main component.

Heretofore, as an improvement of this kind, for example, hexahydrophthalic anhydride was used as one kind of alicyclic carboxylic acid anhydride as one kind of acid component, and it was used in combination with aromatic polybasic acid (JP-A-57-36149). No. JP-A-59-93759
No.), or paratertiary butyl benzoic acid (JP-A-59-59957), terephthalic acid (JP-A-56-118463), and the like. There have been many improvements in oil-modified alkyd resins or oil-free alkyd resins containing an acid anhydride as a component. (JP-A-55-152755, 55-15
2756, 55-152757, 55-15275
No. 8, 56-20068, 58-219231, etc.) However, the compositions obtained from these known techniques are necessarily sufficient in terms of weather resistance, sharpness, gloss, etc. currently required in the market. It couldn't be said to be a thing.

Further, in the conventional alkyd resin, not only the composition of the raw material was changed, but also the molecular structure of the obtained resin was likely to be changed depending on the synthesis conditions.

(Means for Solving Problems) In order to improve or eliminate the drawbacks of the prior art as described above, the present invention uses a specific oligomer using an alicyclic carboxylic acid as one component of a polyhydric alcohol, Relatively less fluctuation in molecular structure during resin synthesis, weather resistance,
An object of the present invention is to provide a resin composition for coating material which can form a coating film having excellent image clarity and gloss.

That is, the present invention relates to [A] one or more hydroxyl groups in a molecule obtained from an alicyclic carboxylic acid anhydride having an icyclohexane ring, a polyhydric alcohol, and a glycidyl ester of a tertiary aliphatic carboxylic acid. Addition reaction product having a group (however, the ratio of each component is: acid anhydride group in (a): hydroxyl group in (b): epoxy group in (c) = 1.0: 0.5 to 4: 0.8 to 1) .2
1] in the resin raw material as a polyol component.
Alkyd resin having a hydroxyl value of 50 to 150, obtained by using ˜50% by weight, 60 to 90% by weight (solid content), [B] crosslinking agent, ... 40 to 10% by weight (solid content) The resin composition for paints consisting of

In the present invention, one of an alicyclic carboxylic acid anhydride having a cyclohexane ring (the above-mentioned component a) is opened with a polyhydric alcohol (the above-mentioned component b) to produce a carboxyl group and a tertiary aliphatic carboxylic acid. An addition reaction product obtained by reacting an epoxy group in glycidyl ester (the above-mentioned component C) is used as an essential component.

The addition reaction product has a structure in which the alicyclic carboxylic acid anhydride is introduced between the polyhydric alcohol and the glycidyl ester of the tertiary aliphatic carboxylic acid, and is a residue of the alicyclic carboxylic acid anhydride. It contains a hydroxyl group produced when a carboxyl group and a glycidyl ester of a tertiary aliphatic carboxylic acid react with each other.

The addition reaction product is synthesized by, for example, the following one-step method or two-step method.

i) One-step method ii) Two-step method In the one-step reaction (i) of the present invention, the epoxy group of the glycidyl ester of a tertiary aliphatic carboxylic acid is parallel to the carboxyl group formed by the ring-opening reaction of an alicyclic carboxylic acid anhydride and a polyhydric alcohol. Follow the process of reacting. Therefore, the ring-opening reaction of the acid anhydride group proceeds with the polyhydric alcohol and also with the secondary alcohol produced by the reaction between the epoxy group and the carboxyl group. Therefore, in the case of the one-step reaction, in order to completely open the ring of the acid anhydride group, the hydroxyl group is in a ratio of 0.5 to 4.0 equivalents, preferably 0.
A range of 9 to 3.0 equivalents is required. If the hydroxyl groups are less than 0.5 equivalent, acid anhydride groups may remain, resulting in thickening of the system or deterioration of the performance of the final product, which is not preferable.

Further, when the epoxy group of the glycidyl ester of tertiary aliphatic carboxylic acid is less than 0.8 equivalent, the residual carboxyl group increases, and conversely, when the epoxy group exceeds 1.2 equivalent, the glycidyl ester remains. Therefore, in both cases, the performance of the final coating film is deteriorated, which is not preferable.

When a two-step reaction is used to obtain an addition reaction product, a hydroxyl group is used in an amount of 1.0 equivalent or more per 1.0 equivalent of an acid anhydride group in order to improve the ring-opening reaction rate of the acid anhydride group. Preferably. The addition reaction product is synthesized in the presence of air or an inert gas atmosphere.

In the case of the one-step reaction, the reaction temperature is 180 ° C. or lower, preferably 100 to 150 ° C.

The state of reaction progress in the case of synthesizing by the one-step reaction is
It can be confirmed by measuring the acid value. In the present invention, however, the acid value is 40 or less, preferably 20 or less. When the acid value exceeds 40, unreacted substances remain, which causes deterioration of the performance of the final coating film, which is not preferable.

In addition, the acid anhydride group of the acid anhydride in the first step reaction in the two-step reaction When the polyhydric alcohol and polyhydric alcohol are reacted with each other, the reaction is carried out at 180 ° C. or lower as in the one-step reaction. That is, under the condition that the formation of water is not recognized, the ring-opening reaction of the acid anhydride group and the addition reaction of the hydroxyl group (semi-esterification) are carried out to obtain the terminal carboxyl group-containing esterified product. Then in the second reaction,
The esterification product is reacted with an epoxy group of a glycidyl ester of a tertiary aliphatic carboxylic acid at a reaction temperature of 280 ° C. or lower, preferably 240 ° C. or lower to obtain an addition reaction product.

The end point of the reaction in the first step can be confirmed by confirming the disappearance of the acid anhydride group. However, since it is generally difficult to confirm by chemical analysis, it is desirable to use an infrared spectrophotometer. The appearing sharply in the vicinity of ^-1 or less yl But about 1770 cm ^-1 and about 1850cm the type of absorption anhydride was attributed to acid anhydride groups in the process of using an infrared spectrophotometer. Therefore, in the first-step reaction, the progress of the reaction can be known by tracing the two absorptions, and can be promptly confirmed by this method.

Next, the end point of the second stage reaction is when the oxidation becomes 40 or less.

Water may be produced in the one-step or two-step reaction. However, reactions under reaction conditions that produce water should be avoided in the present invention. This is because when water is generated, the acid anhydride reacts with water to open the acid anhydride group, and thus the addition reaction of the polyhydric alcohol is inhibited.

An alicyclic carboxylic acid anhydride having a cyclohexane ring used to obtain the addition reaction product of the present invention (component a)
Examples thereof include hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrotrimellitic anhydride, hexahydro-2-methyltrimellitic anhydride and the like. These may be used alone or as a mixture as required.

Examples of the polyhydric alcohol (component (b)) include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, butanediol 1,3, butanediol 1,4,
Butanediol 2,3, pentanediol 1,5, hexanediol-1,6, neopentyl glycol, 2,
2,4-trimethylpentanediol-1,3, hydrogenated bisphenol A, 2,2-di (4-hydroxypropoxyphenyl) propane, glycerin, diglycerin,
Pentaerythritol diallyl ether, trimethylene glycol, 2-ethyl-1,3 hexanediol, trimethylolpropane, cyclohexanedimethanol-
1,4,2,2,4-tetramethylcyclobutanediol-1,3,1,4-bis (2-oxyethoxy) benzene, 2,2,4,4-tetramethylcyclobutanediol-1,3,2 , 2'-Dimethyl-3-hydroxypropyl-2,2-dimethyl-3-hydroxypropionate, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, etc. Is included. These are used alone or as a mixture.

Further, as the glycidyl ester of tertiary aliphatic carboxylic acid (ha component) for obtaining the addition reaction product, for example, glycidyl ester of versatic acid (trade name Cardura E manufactured by Shell Co.) and glycidyl neopentanoic acid are used. Ester, glycidyl ester of neodecanoic acid,
Examples thereof include glycidyl ester of neotridecanoic acid, glycidyl ester of pivalic acid, glycidyl ester of neononyl acid, and glycidyl ester of isononanoic acid. These may be used alone or as a mixture.

Specific examples of each component include the compounds described above. For example, a part of the component is an aromatic polycarboxylic acid anhydride, a part of the component is a monoalcohol, and a component of the c component is It is also possible to replace the part with a polyepoxy resin or the like.

In the synthesis of the addition reaction product of the present invention, both the one-step reaction and the two-step reaction can be carried out without a catalyst, but the following reaction catalyst may be used as necessary to accelerate the reaction. .

For example, secondary and tertiary amines or their inorganic acids or organic acid salts such as dimethylamine hydrochloride,
Triethylamine, benzindimethylamine 2- (dimethylaminomethyl) phenol, 2,4,6-tris (dimethylaminomethyl) phenol and other organic acid salts,
For example, sodium phthalate, zirconium naphthenate,
Metal salts of naphthenic acid, octylic acid, linoleic acid such as chromium naphthenate, lithium naphthenate, zinc octylate, and chromium linoleate can be mentioned. Also, Lewis acids and their organic adducts such as boron trifluoride, boron trifluoride monoethylamine, and metal halides such as lithium chloride, lithium bromide, tin chloride and the like or metal hydroxides,
Examples thereof include sodium hydroxide, lithium hydroxide and the like, hydrogen halides such as hydrobromic acid and the like, alkyl titanates such as butyl titanate and the like. Furthermore, sulfonic acids and sulfonium salts such as paratoluenesulfonic acid, triphenylsulfonium chloride, etc., phosphonic acids and phosphonium salts,
For example, benzenephosphonic acid, triphenylmethylphosphonium, iodide, etc., quaternary ammonium salts such as trimethylbenzylammonium chloride, etc.
Imidazoles or their inorganic or organic adducts such as 2-methyl-4-imidazole, 2
-Naphthyl-4,5-diphenylimidazole, adducts include cyanoethylation type obtained by reacting 2-methylimidazole and acrylonitrile, or 2-methylimidazole and trimellitic acid adduct, and other triphenylphosphine , Triphenyl antimony and the like. These are used alone or as a mixture.

When such a reaction catalyst is used, it is used in an amount of about 0.01 to 10 parts by weight of catalyst based on 100 parts by weight of the reactant. The optimum amount is preferably about 0.1 to 3.0 parts by weight.

The addition reaction product having a hydroxyl group thus obtained is used as a component of a resin raw material, and an oil-modified or oil-free alkyd resin is obtained by using a polyhydric alcohol, a polycarboxylic acid or an anhydride thereof, and optionally an oil or a fatty acid. Get as follows:

Using each of the above raw materials at a reaction temperature of 150 to 280 ° C.,
The alkyd resin as the component [A] in the composition of the present invention can be obtained by carrying out a conventional esterification reaction while successively removing the produced water. The end point of the reaction is determined by measuring the amount of water produced by the esterification reaction or the acid value and viscosity.

From the viewpoint of coating film performance, the acid value at the end of the reaction is preferably 50 or less. It is also possible to dilute with a solvent etc. after completion of the reaction.

When obtaining the alkyd resin, it is essential to use the above-mentioned addition reaction product in the range of 1 to 50% by weight in the resin raw material.

If the amount of the addition reaction product is less than 1% by weight, the effect of the present invention is difficult to be recognized, and if it exceeds 50% by weight, the coating film performance is unbalanced.

In particular, the addition reaction product is preferably used in the range of 10 to 40% by weight in the resin raw material.

Further, other raw materials for obtaining the alkyd resin of the present invention have a hydroxyl value of the resin of 50 to 150, preferably 70.
It is blended so as to be about 130. The weight average molecular weight is preferably 100,000 or less, preferably about 50,000 or less.

As the polyhydric alcohol used for the production of the alkyd resin, the same polyhydric alcohol (component (b)) used for obtaining the addition reaction product can be used without any trouble.

Further, as the polyvalent carboxylic acid or its anhydride used for producing the alkyd resin, maleic acid, fumaric acid, succinic acid, itaconic acid, citraconic acid, mesaconic acid, phthalic anhydride, isophthalic acid, terephthalic acid, dimethyl terephthalic acid is used. Acid, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrotrimellitic anhydride, hexahydro-2-methyltrimellitic anhydride, tetrabromophthalic anhydride, tetrachlorophthalic anhydride, het Acids, 3,6-Endomethylenetetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, methyl nadic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, anthracene-maleic anhydride adduct, rosin-maleic anhydride To list acid addition products Can, which are used alone or as a mixture.

Further, as the oil or fatty acid used in the production of the alkyd resin, for example, castor oil, cottonseed oil, dehydrated castor oil,
Oils such as flaxseed oil, tall oil, safflower oil, soybean oil, tung oil, rice bran oil, corn oil or these fatty acids, isononanoic acid, versatic acid, neopentanoic acid, neodecanoic acid, neotridecanoic acid,
Examples thereof include synthetic fatty acids such as pivalic acid, neononyl acid, and monoglycidyl ester of versatic acid, which may be used alone or as a mixture.

The oil or fatty acid has a final alkyd resin oil length of 50.
% Or less, preferably 30% or less.

In the synthesis of the alkyd resin in the present invention, the reaction can proceed without a catalyst, but a known reaction catalyst can be used as necessary in order to shorten the time industrially. For example tetrabutyl zirconate,
Zirconium naphthenate, tetrabutyl titanate,
Tetraoctyl titanate, stannous oxalate-sodium acetate mixture, stannous oxalate-sodium acetate-zinc acetate mixture, tetraphenyl tin and the like can be mentioned, and the amount thereof is about 0 relative to 100 parts by weight of the total formulation. 0.001 to 1.0 part by weight is used.

Next, the crosslinking agent used in the composition of the present invention will be described.

As the cross-linking agent, any resin or compound that is commonly used for paints and that undergoes a cross-linking reaction with the hydroxyl group in the alkyd resin can be used without any trouble.

Generally speaking, an aminoaldehyde resin, a blocked polyisocyanate compound, an epoxy resin or the like is usually used.

The amino aldehyde resin is a resin obtained from, for example, melamine, benzoguanamine, acetoguanamine, spiroguanamine, urea and the like as raw materials.

The blocked polyisocyanate compound is a compound obtained by blocking the isocyanate group of the polyisocyanate compound with a blocking agent.

As the polyisocyanate compound, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,6-hexamethylene diisocyanate, 4,
4'-diphenylmethane diisocyanate, trans-
Cyclobutane-1,2-bismethyl isocyanate,
1,3-phenylene diisocyanate, isopropylidene bis (4-phenyl isocyanate), bis (4-isocyanate phenyl) sulfone, 4,4'-diphenyl ether diisocyanate, bisphenylene diisocyanate, 3,3'-dimethyl-4,4'- Biphenylene diisocyanate, cyclohexylmethane-4,4 '
-Diisocyanate, xylylene diisocyanate,
2,4-cyclohexylene diisocyanate or a reaction product of an excess of these isocyanate compounds and a polyhydric alcohol can be mentioned. These can be used as one kind or as a mixture of two or more kinds.

Examples of the blocking agent include phenol, cresol, methanol, cyclohexanol, dimethyl malonate, butyl mercaptan, thiophenol, acetanilide, acetaniside, succinimide, diphenylamine, 2-ethylimidazole, urea, thiourea,
Phenyl N-phenylcarbamate, ethyleneimine,
Formaldoxime, methylethylketoxime, sodium bisulfite and the like can be mentioned.

The cross-linking agent can be used alone or as a mixture of two or more kinds.

The alkyd resin (component A) thus obtained and the cross-linking agent (component B) contain 60 to 90% by weight of component A in terms of solid content,
The resin composition for coating material of the present invention is preferably prepared by mixing 70 to 85% by weight and 40 to 10% by weight of component B, preferably 30 to 15% by weight. The mixing ratio is determined in consideration of curability, final coating film performance, etc., and within the range of the ratio, weather resistance of the coating film, sharpness, gloss as well as gasoline resistance, The various properties such as acid resistance, flexibility, hardness, impact resistance, workability, etc. are very excellent.

In the composition of the present invention, other various solvents, color pigments,
It goes without saying that various substances commonly used for paints such as extender pigments, metal pigments, dyes, curing catalysts, curing accelerators, and other precipitation inhibitors can be added and mixed.

The coating resin composition of the present invention is used by mixing the above-mentioned components by a conventional method.

At the time of use, it is applied to the object to be coated by a conventional coating method such as air spray, airless spray, electrostatic coating method.

After coating, if necessary, a temperature of 180 ° C or lower, preferably 14
It is dried by heating at 0 to 150 ° C. for about 20 to 40 minutes.

Thus, a coating film having excellent weather resistance, sharpness and gloss can be obtained.

Therefore, the coating resin composition of the present invention can be widely applied to fields requiring high weather resistance and the like, and is particularly suitable as an intermediate coating and / or top coating finishing composition for automobiles.

Hereinafter, details of the present invention will be described with reference to examples. “Parts” or “%” shall be indicated as “parts by weight” or “% by weight”.

Prior to the examples, addition reaction products were synthesized as follows.

Synthesis Example 1 Synthesis of Addition Reaction Product by One-Step Reaction In one flask equipped with a stirrer, condenser, thermometer, nitrogen gas inlet, hexahydrophthalic anhydride 15
4.0 parts (an acid anhydride group 1.0 equivalent), neopentyl glycol 104.0 parts (hydroxyl group, 2.0 equivalent), Cardura E25
3.0 parts (trade name of Shell Company, 1.0 equivalent of epoxy group) and 1.5 parts of triphenylphosphine were charged and reacted at 130 ° C. for 4 hours under a nitrogen gas atmosphere to give an acid value of 4.7.
The reaction was terminated at the point of becoming, and a hydroxyl group-containing addition reaction product [P-1] was obtained.

The Gardner color number of the addition reaction product is 4 (nonvolatile content 80
% Methylisobutylketone solution: same as below), viscosity is 1.3 Stokes Poise (20 ° C .: 80% methylisobutylketone solution with non-volatile content: same below), acid value is 4.6.
(Solid content: same as below) and hydroxyl value was 221 (solid content: same as below).

Synthesis Example 2 Synthesis of Addition Reaction Product by Two-Step Reaction In the same flask as in Synthesis Example 1, the first step reaction was 154.0 parts of hexahydrophthalic anhydride (1.0 equivalent of acid anhydride group) and neopentyl glycol. Charge 104.0 parts (2.0 equivalents of hydroxyl groups) and add 120 under nitrogen atmosphere.
Reacted at ℃ for 2 hours. When the residual amount of acid anhydride groups was measured by an infrared spectrophotometer, the reaction rate was 97%. Next, as the second-step reaction, 253.0 parts of cardura E (1.0 equivalent of epoxy group) was added to the product obtained in the first-step reaction, and the reaction was carried out at 200 ° C. for 3 hours to give an acid value of 4.5. The reaction was terminated at the point of becoming, and a hydroxyl group-containing addition reaction product [P-2] was obtained.

The addition reaction product has a Gardner color number of 4 and a viscosity of 1.4.
Stokes Poise, acid value 4.5, hydroxyl value 2
It was 20.5.

Synthesis Example 3 Synthesis of Addition Reaction Product by Two-Step Reaction In the same flask as in Synthesis Example 1, the first step reaction was 154.0 parts of hexahydrophthalic anhydride (1.0 equivalent of acid anhydride group) and cyclohexanediene. 144.0 parts of methanol (2.0 equivalents of hydroxyl groups) were charged, and 2.5 at 100 ° C.
After reacting for a time, the reaction was terminated when the acid value reached 188.0. The reaction rate was almost 100%.

To the reaction product of the first step, 253.0 parts of cardura E (1.0 equivalent of epoxy group) and 0.83 part of triphenylphosphine as a reaction catalyst were added and reacted at 150 ° C. for 2 hours to give an acid value of 4. The reaction was terminated at 9 and a hydroxyl group-containing addition reaction product [P-3] was obtained.

The addition reaction product has a Gardner color number of 4 and a viscosity of 3.0.
Stokes Poise, acid number 4.9, hydroxyl number 2
It was 05.

Synthesis Example 4 Synthesis of Addition Reaction Product by Two-Step Reaction In the same flask as in Synthesis Example 1, the first step reaction was 168.0 parts of methylhexahydrophthalic anhydride (1.0 equivalent of acid anhydride group), Charge 2,4.0 parts of 2,2'-dimethyl-3-hydroxypropyl-2,2-dimethyl-3-hydroxypropionate (2.0 equivalents of hydroxyl group), and in a nitrogen gas atmosphere at 100 ° C for 2.5 hours. React,
The reaction was terminated when the acid value reached 151.0. The reaction rate was almost 100%.

240.0 parts (1.0 equivalent of epoxy group) of glycidyl ester of neononyl acid was added to the reaction product of the first step,
After reacting at 200 ° C. for 2 hours, the reaction was terminated when the acid value reached 5.9, and the hydroxyl group-containing addition reaction product [P
-4] was obtained.

The addition reaction product has a Gardner color number of 5 and a viscosity of 2.8.
Stokes Poise, acid number 5.8, hydroxyl number 1
It was 84.

Synthesis Example 5 Synthesis of Addition Reaction Product by Two-Step Reaction In the same two flasks as in Synthesis Example 1, the first step reaction was 462.0 parts of hexahydrophthalic anhydride (acid anhydride group 3.
(0 equivalent) and 134.0 parts of trimethylolpropane (3.0 equivalent of hydroxyl group) were charged and reacted at 100 ° C. for 1 hour, and the reaction was terminated when the acid value reached 278.9.

To the reaction product of the first stage, 759.0 parts of Cardura E (3.0 equivalents of epoxy group) and 3.5 parts of triphenylphosphine as a reaction catalyst were added and reacted at 150 ° C. for 3 hours to give an acid value of 3. The reaction was terminated at the time when it reached 3, and a hydroxyl group-containing addition reaction product [P-5] was obtained.

The addition reaction product has a Gardner color number of 5 and a viscosity of 8.6.
Stokes Poise, acid number 3.2, hydroxyl number 1
It was 26.

Synthesis Example 6 Synthesis of Addition Reaction Product by Two-Step Reaction In the same flask as in Synthesis Example 1, the first reaction was 308.0 parts of hexahydrophthalic anhydride (2.0 equivalents of acid anhydride group) and neopentyl. Charge 104.0 parts of glycol (2.0 equivalents of hydroxyl group), 100 ° C under nitrogen gas atmosphere
After reacting for 2.5 hours, the reaction was terminated when the acid value reached 272.

506.0 parts (2.0 equivalents of epoxy group) of Cardura E was added to the reaction product of the first step, and the reaction was carried out at 200 ° C. for 1 hour. When the acid value reached 1.9, the reaction was terminated and hydroxyl group was added. A group-containing addition reaction product [P-6] was obtained.

The addition reaction product has a Gardner color number of 2 and a viscosity of 3.2.
Stokes Poise, acid number 1.9, hydroxyl number 9
It was 16.

Example 1 A reactor equipped with a stirrer, a thermometer, a nitrogen gas introducing device, a reflux condenser (with a dehydration trap), and a heating device was placed in an addition reaction product [P-1] (200.0 parts) and trimethylolpropane. 185.0 parts, neopentyl glycol 110.
Charge 5 parts, phthalic anhydride 187.3 parts, hexahydrophthalic anhydride 131.1 parts, adipic acid 56.1 parts, coconut oil fatty acid 130.0 parts and xylene 25.0 parts, and from room temperature to 160 ° C for 1 hour. Then, raise the temperature to 160-240 ° C over 3 hours, and then continue the reaction at 240 ° C.
The reaction was terminated when the acid value reached 9.0. Then, cooling was continued, and when the reaction product reached a temperature of 150 ° C., 601.7 parts of xylene was added and mixed to obtain a nonvolatile content of 60%,
Viscosity 2.6 Stokes Poise, Acid value 8.8 (solid content),
An alkyd resin solution having a hydroxyl number of 74 (solid content) was obtained.

Examples 2 to 9 In the same manner as in Example 1, the reaction was carried out with the formulations shown in Table 1 to obtain alkyd resin solutions.

Comparative Examples 1 to 4 In the same manner as in Example 1, the reaction was performed according to the formulation shown in Table 1 to obtain an alkyd resin solution.

Alkyd resin solutions obtained in Examples 1 to 9 and Comparative Examples 1 to 4, butyl etherified melamine resin and titanium oxide were alkyd resin / melamine resin = 7/3 (solid content ratio), pigment weight concentration 50%. And kneaded to give Solvesso 100 / Solvesso 150 / Xylene /
Dilute with a mixed solvent consisting of n-butanol = 70/15/10/5 and have a viscosity of 23 seconds (Ford Cup No.
The temperature was adjusted to 4: 20 ° C.) to obtain paints.

Then, each coating material was applied onto a steel sheet by air spraying so that the dry film thickness was 30 μm, allowed to stand at room temperature for 15 minutes, and then heated and dried in a hot air drying oven at 150 ° C. for 20 minutes.

The coating film performance comparison of the obtained test pieces is shown in Table 2.

As is clear from the above results, the coating film obtained from the resin composition of the present invention was found to have a particularly excellent gloss retention rate after an oil-modified or oil-free alkyd resin co-weathering test. .

On the other hand, in Comparative Examples 1 to 4, the general coating film performance was excellent, but the weather resistance was very poor.

Further, the coating film of the present invention does not change gasoline resistance and acid resistance at all even when the oil length is increased (Example 7: oil length 30%), but in Comparative Example (Comparative Example 2: oil length 30%). These performances tended to decrease.

Claims (3)

[Claims] 1. [A] One or more hydroxyl groups in a molecule obtained from an alicyclic carboxylic acid anhydride having an icyclohexane ring, a polyhydric alcohol and a glycidyl ester of a tertiary aliphatic carboxylic acid. [Wherein the ratio of each component is the acid anhydride group in (a): the hydroxyl group in (b): the epoxy group in (c) = 1.0: 0.5-4:
0.8 to 1.2 equivalents] is used as a polyol component in the resin raw material in an amount of 1 to 50% by weight, and an alkyd resin having a hydroxyl value of 50 to 150 ... 60 to 90% by weight ( Solid content), [B] cross-linking agent ... 40 to 10% by weight (solid content) of a resin composition for coating material. 2. The resin composition for coating composition according to claim 1, wherein the crosslinking agent is an aminoaldehyde resin. 3. The resin composition for coating composition according to claim 1, wherein the crosslinking agent is a mixture of an aminoaldehyde resin and a blocked polyisocyanate compound.