JP3029627B2 - Resin composition for paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a resin composition for coatings which has significantly improved abrasion resistance and also has excellent weather resistance and chemical resistance.

[Prior art] As a top coat of an automobile body or the like, the finished appearance (gloss, smoothness), weather resistance, chemical resistance, mechanical properties,
Adhesion to the undercoat, adhesion during recoating, etc. are generally required performance, but in recent years, with the growing need for coating color design, dark and clear colors such as dark blue, black, and red occupy Since the ratio has increased, there has been a problem that the finished appearance is deteriorated due to scratches on the coating film surface.

Scratch on automobile body refers to scratches caused by the impact of cloth, brushes, automatic car washer, or brush swabs used during car washing, scratches, and the impact of flying sand flying up during running. The abrasion resistance (scratch resistance) is a property required for a coating film from immediately after coating to after natural exposure.

Conventionally, as a scratch-resistant paint, it has been known to form a hard coat using an ultraviolet-curable paint and a silicone-based paint. There is a problem that the silicone paint requires high-temperature baking, so that the object to be coated is limited, repainting and repair cannot be performed, and the cost of the paint is high.

Also, as a thermosetting resin composition for coatings having excellent weather resistance and improved low-temperature flexibility, it comprises a lactone-modified fluorinated copolymer obtained by grafting a lactone compound to a fluorinated copolymer and a curing agent. Paints have been proposed (Japanese Unexamined Patent Publication
59-96177). The coating film obtained from this resin composition has a high degree of flexibility and is excellent in weather resistance.However, since the denaturation reaction is carried out at 100 to 160 ° C. for several hours, the polymer solution is colored or the lactone-modified fluorine-containing copolymer is used. There was a problem that the storage stability of the polymer was poor.

[Problems to be Solved by the Invention] An object of the present invention is to overcome the above-mentioned problems of the prior art and to provide a top coat such as an automobile body with excellent scratch resistance, weather resistance, and weather resistance. An object of the present invention is to provide a resin composition having general coating properties such as chemical properties and water resistance, and paint properties such as coloring property and storage stability.

[Means for Solving the Problems] The present invention is a resin composition for coatings, comprising the following (A), (B) and (C).

(A) a hydroxyl group-containing solvent-soluble fluorine-containing copolymer having a fluoroolefin-based polymerization unit and a vinyl-based polymerization unit having a suspended polyester chain, (B) a number-average molecular weight of 200 to 3,000, and a hydroxyl group at a terminal A polyol having a hydroxyl value of 40 to 800 mgKOH / g; and (C) a curing agent having a functional group that reacts with a hydroxyl group.

The fluorinated copolymer (A) in the coating resin composition of the present invention is a fluoroolefin-based polymer unit and a vinyl-based polymer unit having a suspended polyester chain (hereinafter, may be abbreviated as a specific polyester-based polymer unit). ).

Here, the fluoroolefin-based polymerized unit is a unit obtained by polymerizing a fluoroolefin-based monomer such as tetrafluoroethylene, chlorotrifluoroethylene, trifluoroethylene, hexafluoropropylene, or perfluoro (propyl vinyl ether).

Further, the vinyl-based polymer unit is an olefin-based compound,
Contains α-β unsaturated groups such as vinyl ether compounds, vinyl ester compounds, allyl ether compounds, allyl ester compounds, isopropenyl ether compounds, isopropenyl ester compounds, acryloyl group-containing compounds, and methacryloyl group-containing compounds. A unit in which a compound (generally referred to as a vinyl monomer) is polymerized.

Further, the vinyl-based polymerization unit having a suspended polyester chain is a unit in which a vinyl-based monomer having a polyester chain is polymerized, or a polyester chain is suspended on a vinyl-based polymerization unit having a functional group (for a polyester compound). Addition or the formation of a polyester chain such as a ring-opening reaction of a lactone compound).

Since the resin composition for coating of the present invention employs such a fluorine-containing copolymer having a specific pendant chain as the fluorine-containing copolymer (A), the cured coating film has excellent recoverability. It becomes an elastic coating. As a result, the coating film responds to the load of rubbing as an elastic body, absorbs it as elastic deformation without destruction, and when the load is removed, the deformation is quickly recovered, and the effect of scratches or inconspicuousness is obtained. Can be In particular, this effect is remarkable when a fluorine-containing copolymer having a hydroxyl group at the terminal of the suspended polyester chain is employed.

In order to obtain the fluorinated copolymer (A), a fluoroolefin monomer and a vinyl monomer having a polyester chain (hereinafter sometimes abbreviated as a specific polyester)
Or a method in which a polyester chain is suspended from a copolymer of a fluoroolefin monomer and a vinyl monomer having a reactive group. The former method is preferred because it is free from coloring and has excellent storage stability. The manufacturing method will be specifically described below.

The specific polyester in the present invention preferably has an α-β unsaturated group at one end of the molecule and a hydroxyl group or carboxylic acid group at the other end.

Such a specific polyester can be synthesized, for example, by the following method.

A method of subjecting a polyester having a carboxylic acid group or a hydroxyl group at both terminals to an esterification reaction with a compound having an α-β unsaturated group at one end and a hydroxyl group or a carboxylic acid group at the other end.

In the presence of a compound having an α-β unsaturated group at one end and a hydroxyl group or a carboxylic acid group at the other end, a polycondensation reaction between a polyhydric alcohol and a polycarboxylic acid is performed, or a lactone compound is subjected to a ring-opening polymerization reaction. Method.

Here, as the compound having an α-β unsaturated group at one end of the molecule and a hydroxyl group or a carboxylic acid group at the other end, hydroxyalkyl vinyl ether, vinyl ester of hydroxyalkanecarboxylic acid, allyl ester of hydroxyalkanecarboxylic acid, hydroxyalkyl Allyl ether, carboxyalkyl vinyl ether, carboxyalkyl allyl ether, methacrylic acid, acrylic acid, hydroxyalkyl ester of methacrylic acid, hydroxyalkyl ester of acrylic acid, carboxyalkyl ester of methacrylic acid, carboxyalkyl ester of acrylic acid, vinyl having hydroxyl group Compounds in which a carboxylic acid group is introduced by modifying a system compound with a polyvalent carboxylic anhydride are exemplified.

The specific polyester in the present invention is produced by various methods as described above, and in particular, a method of reacting a hydroxyl group-containing vinyl ether such as hydroxyalkyl vinyl ether with a lactone compound is easy to produce. Is preferred because of its excellent copolymerizability.

Here, examples of the lactone compound include β-propiolactone, pivalolactone, γ-butyrolactone, δ-valerolactone, and ε-caprolactone. In particular, ε-caprolactone is preferably employed in that it has excellent reactivity with a hydroxyl group-containing vinyl ether, and that the cured product of a fluorine-containing copolymer obtained by copolymerizing the product has excellent scratch resistance.

In the reaction between the hydroxyl group-containing vinyl ether and the lactone compound, it is preferable to use an appropriate catalyst because the reaction temperature can be lowered and the reaction time can be shortened. Examples of such a catalyst include dibutyltin dilaurate, stannous octoate, tetrabutyltitanate, potassium carbonate and the like. The reaction is carried out at a temperature of about 100 to 160 ° C., and is almost completed in about 1 to 10 hours. Unreacted hydroxyl group-containing vinyl ether and lactone compound can be removed by distillation under reduced pressure or extraction with a solvent such as n-hexane.

The specific polyester in the present invention preferably has an average of about 2 to 10 ester bonds in the molecule. The number of ester bonds affects the effect depending on the size and structure of the hydrocarbon groups existing between the ester bonds, but those with a small number of ester bonds are caused by the scratch resistance of the cured product of the fluorine-containing copolymer. Unsatisfactory properties cannot be obtained. Further, too much is not preferred because the weather resistance and water repellency which are characteristics of the fluorine-containing copolymer are impaired.
In particular, those having 2 to 6 ester bonds are preferable. It is particularly preferable that such a specific polyester is a linear compound.

In the present invention, the fluoroolefin-based monomer is preferably a perhaloolefin, particularly chlorotrifluoroethylene or tetrafluoroethylene. The fluoroolefin monomer is not limited to a single monomer, and may be 2
It can also be used in the form of a mixture of more than one species.

In the present invention, other comonomer can be used as a copolymer component. Examples of such a comonomer include olefins such as ethylene, propylene and isobutylene, haloolefins such as vinyl chloride and vinylidene chloride, unsaturated carboxylic esters such as methyl methacrylate, vinyl acetate and n-vinyl butyrate. Vinyl carboxylate, allyl ether,
Examples include allyl esters, isopropenyl ethers, and vinyl compounds having a reactive group such as a hydroxyl group, an acid amide group, an epoxy group, or a carboxylic acid group.

The fluorine-containing copolymer in the present invention is subjected to a copolymerization reaction by acting a polymerization initiator or a polymerization initiator such as ionizing radiation in the presence or absence of a polymerization catalyst in a predetermined ratio of the monomer mixture. Obtained by tightening.

Here, as the polymerization initiator, a water-soluble one or an oil-soluble one can be appropriately used depending on the polymerization type or the polymerization medium.

Specifically, as the water-soluble initiator, a redox initiator composed of a persulfate such as potassium persulfate, hydrogen peroxide or a combination thereof with sodium hydrogen sulfite and a reducing agent such as sodium thiosulfate, Or an inorganic initiator such as a system in which a small amount of iron, ferrous salt, silver nitrate, etc. coexist, or a dibasic acid peroxide such as disuccinic peroxide, diglutaric peroxide, or monosuccinic peroxide, or azobisisobutylamidine dioxide. Organic initiators such as hydrochloride are exemplified.

Further, t-butyl peroxyisobutyrate, t-butyl peroxyacetate, t-butyl peroxyisobutyrate,
Examples thereof include peroxyester-type peroxides such as -butylperoxypivalate, dialkylperoxydicarbonates such as diisopropylperoxydicarbonate, benzoyl peroxide, and azobisisobutyronitrile.

The amount of the polymerization initiator used can be appropriately changed depending on the type, copolymerization reaction conditions, etc., but is usually about 0.005 to 5% by weight, especially about 0.005 to 0.5% by weight, based on the total amount of the monomers to be copolymerized. Is adopted.

In the copolymerization reaction in the present invention, the reaction mode is not particularly limited, and bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization, and the like can be employed, but the stability of the polymerization reaction operation, the separation of the produced copolymer, and the like. Emulsion polymerization in an aqueous medium or solution polymerization using a saturated halogenated hydrocarbon containing one or more fluorine atoms as a solvent, such as alcohols, esters, aromatic hydrocarbons such as t-butanol, etc. from the viewpoint of easiness and the like. Are preferred.

In addition, when performing a copolymerization reaction in an aqueous medium,
It is preferred to add a basic buffer so that the pH of the solution during the polymerization does not fall below 4, preferably below 6. In the case of solution polymerization, the addition of a basic substance is effective. Further, the copolymerization reaction in the present invention is a batch system, a semi-continuous system,
It can be performed by a continuous operation or the like.

In the copolymerization reaction of the present invention, the copolymerization reaction temperature is -30.
The optimal value can be appropriately selected depending on the type of polymerization initiation source, polymerization medium and the like within the range of from 0 ° C to + 150 ° C. However, when the copolymerization reaction is carried out in an aqueous medium, 0 ° C to + 100 ° C, preferably About 10 ° C to 90 ° C can be adopted. The reaction pressure can be appropriately selected, but is usually 1 to 100 kg / cm ² , particularly ² to 50 kg / cm ²
It is desirable to adopt a degree.

Further, the copolymerization reaction can be carried out appropriately in the presence of a chain transfer agent.

In the present invention, the copolymerization ratio of the specific polyester, the fluoroolefin-based monomer and, if necessary, the other comonomer is such that the specific polyester-based polymerized unit is 2 to 30 mol% and the fluoroolefin-based polymerized unit is 30%. 7070 mol%, and the comonomer is preferably 0-68 mol%. In particular, 5 to 15 mol% of a specific polyester-based polymerization unit, 40 to 60 mol% of a fluoroolefin-based polymerization unit, and 25 to 55 mol% of a comonomer.
Preferably it is mol%.

If the specific polyester-based polymerization unit is too small, the scratch resistance of the cured product of the fluoropolymer is not sufficiently obtained, and
If the amount is too large, weather resistance and water repellency deteriorate, which is not preferable. Further, if the amount of the fluoroolefin-based polymerization unit is too small, sufficient weather resistance cannot be obtained, and if the amount is too large, the solvent which is insoluble or soluble in the solvent is limited. When the coalescing is used for a paint, it is not preferable because handling becomes difficult or complicated. The comonomer is copolymerized to such an extent that the weather resistance, elongation, flexibility and the like of the fluorinated copolymer are not impaired. It is preferable to copolymerize a vinyl ester of an alkyl vinyl ether or an alkane carboxylic acid as a comonomer because the solubility of the fluoropolymer in a solvent is improved and the dispersibility of the pigment is improved.

The polyol (B) component does not compensate for the reaction point with the curing agent which is insufficient when the fluorocopolymer (A) alone is used as a crosslinked coating film, and has a scratch resistance, a solvent resistance, and a water resistance by an elastic deformation coating film. It is used as an essential component for achieving compatibility of general coating properties such as water resistance and weather resistance.

Therefore, the component (A) and the component (C) alone have good scratch resistance, but do not have sufficient solvent resistance, stain resistance, and weather resistance because they contain a polyester group having high elasticity.
The component (B) is an essential component for realizing a true maintenance-free coating film characterized by abrasion resistance and weather resistance while satisfying general coating film performance.

The component (B) has a number average molecular weight of 200 to 3000, has a terminal hydroxyl group, and has a hydroxyl value of 40 to 800 mgKOH / g.
Is a polyol.

When the number average molecular weight is smaller than the above range, the solvent resistance, water resistance and weather resistance of the cured coating film are insufficient, and when it is larger, the coating workability, particularly the finished appearance, is inferior. On the other hand, if the hydroxyl value is less than 40 mgKOH / g, the crosslinking reaction point with the curing agent of the component (C) will be insufficient, and the scratch resistance and solvent resistance will decrease. Adversely affect.

The main chain of the component (B) may contain an ether group or an ester group. Examples of the polyol containing such an ether group or ester group include polyethylene glycol, polypropylene glycol, polybutylene glycol,
Reaction products of glycols with functional aliphatic or alicyclic acids, polycarbonate diols, bifunctional polycaprolactones, for example, R [(OCO (CH ₂ ) ₅ ) _n OH] ₂ [product of Daicel, Praxel 205 ( Molecular weight 530), Praxel 208 (molecular weight 800), Praxel 210 (molecular weight 1000),
Bifunctional compounds such as Placcel 220 (molecular weight 2000)] are preferred. Also, trifunctional polycaprolactones, for example, R [(OCO (CH ₂ ) ₅ ) _n OH] ₃ [products of Daicel, Praxel 303 (molecular weight 300), Praxel 305 (molecular weight 550), Plaxel 308 (molecular weight 850) , Plaxel 3
12 (molecular weight 1250), Plaxel 320 (molecular weight 2000)] and the like.

Examples of the curing agent (C) having a functional group that reacts with a hydroxyl group include an alkyl etherified melamine resin, an isocyanate compound, a phenol resin, a xylene resin, and a toluene resin. Is preferred because it is easy to obtain a coating film having excellent weather resistance and mechanical properties.

Examples of the alkyl etherified melamine resin include melamine resins alkylated, such as methyl etherification, butyl etherification, and isobutyl etherification, urea resins, and benzoguanamine resins.

Examples of the isocyanate compound include a polyisocyanate compound and a blocked polyisocyanate compound.

Examples of the polyisocyanate compound include hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, isophorodiisocyanate, tolylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and 4,4'-methylene bis (cyclohexyl isocyanate). Burette type adducts, isocyanuric ring type adducts, polyhydric alcohol adducts, and the like.

Of these, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4'-
Non-yellowing types such as methylene bis (cyclohexyl isocyanate) and xylylene diisocyanate
It is preferable in terms of weather resistance.

As the isocyanate blocking agent, those usually used, for example, phenol-based, alcohol-based, oxime-based, lactam-based, and active methylene-based are mentioned.

The resin composition for a coating material of the present invention contains the above components (A) to (C) as main components, and their constituent ratios are (A) to (A).
Component (A) is from 10 to 90 based on the total weight of component (C).
% By weight, preferably 20 to 80% by weight, and the component (B) is 5 to 40% by weight.
% By weight, preferably 10 to 40% by weight, and (C) component
It is 10 to 50% by weight, preferably 20 to 40% by weight.

If the content of the component (A) is less than 10% by weight, the composition does not exhibit sufficient self-healing against the external load of the scratches, and the abrasion resistance is insufficient. It is not preferable because the property is lowered.

When the amount of the component (B) is less than 5% by weight, the crosslinking point with the component (C) is insufficient and the crosslinked structure is not sufficiently formed, and the mechanical strength, solvent resistance, weather resistance, etc. of the coating film are reduced, While 40
If the content is more than 10% by weight, the coating film becomes too hard and brittle, and the abrasion resistance decreases, which is not preferable.

If the amount of the component (C) is less than 10% by weight, the coating film is not sufficiently cured, and an elastically deformable coating film suitable for scratch resistance is not sufficiently formed. If the amount is more than 50% by weight, the coating film becomes rigid. The unreacted curing agent remaining in the coating film is not preferable because chemical resistance and weather resistance are reduced.

The resin composition for a coating material of the present invention may contain, if necessary, a surface conditioner, a catalyst for accelerating curing, a thickener, a color-separation inhibitor, an antifoaming agent, an anti-cissing agent, an ultraviolet absorber, an antioxidant, and light. Stabilizers and other additives can be added.

In forming the resin composition for a coating material of the present invention into a coating material, the fluorine-containing copolymer (A), the polyol (B), and the curing agent (C)
In the case of solid color,
A commonly used coloring pigment is dispersed and, if necessary, an additive and a solvent are added to form a paint. This was coated with a diluting solvent to a coating viscosity of 18-25 using a Ford cup # 4 (20 ° C).
Dilute in seconds. Then, if necessary, an undercoat or an intermediate coating film is formed on the base plate, and then directly coated with one coat solid or enameled with two coats and one bake enamel, and then coated with enamel. The coating method is an air atomization method, a rotary atomization method, an airless method, an electrostatic coating, a dip coating, or the like.

Curing conditions after coating, the coating object, depending on the type of curing agent used, etc., if cured at room temperature to 250 ° C. for 1 to 60 minutes, a cured coating film having excellent scratch resistance aimed at by the present invention is obtained. can get.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. Parts and% in the examples are parts by weight and% by weight unless otherwise specified.

"Synthesis example 1" 830 g of xylene, 242 g of ethanol were placed in a 2.5 L stainless steel autoclave with a stirrer (withstand pressure of 30 kg / cm ² G).
Cyclohexyl vinyl ether (hereinafter referred to as CHVE) 98
g, ethyl vinyl ether (hereinafter referred to as EVE) 94 g, A1
(See footnote in Table 1) 250 g and 10 g of potassium carbonate are charged, and dissolved air is removed by repeating cooling and degassing and pressurizing with nitrogen gas.

Next, 303 g of chlorotrifluoroethylene (hereinafter referred to as CTFE) is introduced into the autoclave, and the temperature is raised. When the temperature in the autoclave reaches 65 ° C, the pressure is 3.8 kg / cm ² G
Is shown. Then, azobisisobutyronitrile (hereinafter, referred to as
43 g of a 20% xylene solution of AIBN) is added to start the reaction. After that, the reaction was continued with stirring for 16 hours,
When the autoclave is cooled down to 0.2 kg / cm ² G, the reaction is stopped by water cooling. After reaching room temperature, unreacted monomers are purged and the autoclave is opened.

The obtained copolymer solution was poured into water to precipitate a polymer, followed by washing and drying to obtain a copolymer B1.

The polymer yield was 633 g, the intrinsic viscosity [η] (in tetrahydrofuran at 30 ° C.) was 0.11 dl / g, the weight average molecular weight M _{w in} terms of polystyrene measured by GPL, the number average molecular weight M _n and the ratio M _w / M _n. Were 6,500, 14300, and 2.2, respectively. Further, the hydroxyl value (mgKOH / g) was 40.

"Synthesis Examples 2 to 5" Copolymers were synthesized under the conditions shown in Table 1. The physical properties of the obtained copolymers B2 to B6 are also shown. The polymerization conditions not described in the table are the same as in Synthesis Example 1.

"Synthesis Example 7" The fluorinated copolymer shown in Synthesis Examples 1 to 6 was prepared by
Denaturation was performed by the method described in 49323. Specifically, the fluorinated copolymer B1 and the fluorinated copolymers B3 to B6
Was added to a solution of 1.16 parts by weight of succinic anhydride dissolved in 6.63 parts by weight of acetone.
Add 3 parts by weight. This was heated and reacted at 70 ° C. for 15 hours. Termination of the reaction is due to the infrared spectrum of succinic anhydride.
There is no characteristic absorption of 1850 cm ^-1 and 1780 cm ^-1, characteristic absorption of the half-ester of the resulting succinic acid (carboxyl group and an ester group of the 1760 cm ^-1 1710 cm ^-1) was confirmed by the increased. Acetone is removed by vacuum distillation of the resulting reaction solution at 50 ° C. and 3 mmHg, and xylene is added to obtain a modified carboxyl group-containing fluorocopolymer solution C1 and C3 to C6 with a heating residue of 65%. Was. Further, a modification reaction was performed in the same manner as described above except that 100 parts by weight of the solution of the fluorinated copolymer B2 (heating residue: 65%) was used and the amount of succinic anhydride was changed to 0.58 parts by weight according to Synthesis Example 2. A solution C2 of a modified product of a fluorinated copolymer containing a carboxyl group was obtained. Table 2 summarizes the above results. Table 2 shows the varnish characteristics of C1 to C6 and the corresponding fluorine-containing copolymers 12B1 to B6.

"Examples 1 to 6 and Comparative Examples 1 and 2" Eight types of clear coat paints were produced by using the fluorine-containing copolymer solution of Synthesis Example 7 and blending the paints shown in Table 3.

Production Example of Base Coating Paint 10 parts of styrene, 25 parts of methyl methacrylate, 35 parts of ethyl acrylate, 15 parts of n-butyl methacrylate and 2 parts of acrylic acid were polymerized in xylene using a polymerization initiator AIBN to obtain a resin component 48. % Acrylic resin solution was obtained. Using this acrylic resin solution, a solvent-type base coat E1 was prepared with the following composition.

Acrylic resin solution 200 parts Melamine resin Cymel 303 manufactured by Mitsui Cyanamid Co., Ltd. 20 parts p-toluenesulfonic acid solution 4.0 parts Carbon black FW # 200 manufactured by Degussa 2.0 parts Next, this base coat E1 was treated with 40 parts of toluene, 40 parts of ethyl acetate, and acetic acid. Viscosity 1 with mixed solvent consisting of 20 parts of cellosolve
It was diluted for 3.5 seconds (Ford Cup # 4/20 ° C) and used for painting.

Preparation of Test Plate and Its Evaluation A cationic electrodeposition paint for automobiles was applied on a 0.8 mm thick dull steel plate that had been subjected to a zinc phosphate chemical conversion treatment, and baked at 170 ° C. for 30 minutes. Next, apply an intermediate paint for automobiles,
After baking for 0 minutes, the sample was ground with a sandpaper of # 600, dried, degreased with white gasoline, and used as a test material.

After adjusting the viscosity of the base coating material E1 to 13.5 seconds on this material, using an air spray gun W-61 (manufactured by Iwata Cup Co.), it was applied to a dry film thickness of 18 μm,
After leaving at room temperature for 3 minutes, the clear coat paint described in Table 3 adjusted to a viscosity of 25 seconds was wet-on-wet coated to a dry film thickness of 30 μm using an air spray gun W-61, and then at room temperature for 10 minutes. After the standing, baking was performed at 140 ° C. for 30 minutes in a hot air drying furnace to prepare a test plate. Table 4 shows the results of evaluating the scratch resistance and general coating film performance of the obtained test plates by the following evaluation methods.

"Evaluation method" Coating appearance: The finished appearance of the coating film was evaluated based on the following criteria based on visual luster and feeling of holding. ◎: very good, ○: good, △:
Poor, x: extremely poor.

Gloss (60 ゜): Digital variable-angle gloss meter manufactured by Suga Test Instruments Co., Ltd.
Measured using UGV-4D.

Pencil hardness: The scratch hardness is measured using Mitsubishi Pencil Uni.

Impact resistance: Shooting tip radius using DuPont impact tester
Tested with 1/2 inch and falling bell weight 500g. Indicated by the maximum height where cracks do not enter the painted surface (in 5 cm increments).

Moisture resistance: The test plate was placed in a thermo-hygrostat at 50 ° C and 98% RH for 120 hours, and the state of the coated surface immediately after removal was evaluated.

Gasoline resistance: After immersion in regular gasoline manufactured by Nippon Oil Co. at room temperature for 24 hours, the appearance was visually evaluated.

Acid resistance: Spot 0.3cc of 10% sulfuric acid on the painted surface,
After standing for a while, wash with water and observe the coated surface.

Alkali resistance: 0.3cc of 10% aqueous sodium hydroxide solution was spotted on the coated surface, left at 20 ° C for 24 hours, washed with water, and the coated surface was observed.

Weather resistance: The coating film after exposure for 3000 hours with a sunshine weather meter was observed and evaluated.

Scratch resistance: The state of the coated surface of the coated plate after the car with the test plate attached to the roof was washed 20 times with a car washer was observed according to the following evaluation criteria. A: Passed with almost no scratches by visual observation
：: Slight scratches were found but the degree was very slight. △: Scratch was noticeable and failed. ×: Scratch was noticeable and failed.

[Effect of the Invention] The coating resin composition of the present invention has excellent abrasion resistance and forms a highly weather-resistant coating film in which hardness, water resistance, chemical resistance, chemical resistance, etc. are balanced. Therefore, it is extremely useful for painting automobile bodies and home appliances.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C09D 127/12 C08L 27/12

Claims (5)

(57) [Claims] (1) A resin composition for a paint, comprising the following (A), (B) and (C): (A) a hydroxyl group-containing solvent-soluble fluorine-containing copolymer having a fluoroolefin-based polymerization unit and a vinyl-based polymerization unit having a suspended polyester chain, (B) a number-average molecular weight of 200 to 3,000, and a hydroxyl group at a terminal A polyol having a hydroxyl value of 40 to 800 mgKOH / g; and (C) a curing agent having a functional group that reacts with a hydroxyl group. 2. The resin composition for a paint according to claim 1, wherein the suspended end of the polyester chain is a hydroxyl group. 3. The coating resin according to claim 1, wherein the fluorocopolymer contains 40 to 60 mol% of the fluoroolefin-based polymer units and 5 to 15 mol% of the vinyl-based polymer units. Composition. 4. The coating resin composition according to claim 1, wherein said vinyl polymer unit is a polymer unit having an average of 2 to 6 ester bonds. 5. The coating resin composition according to claim 1, wherein said polyol is a polycaprolactone polyol.