JP2001146575A - Chipping-resistant coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop a coating composition having high resistance to chipping properties by finding a correlation of the viscoelasticity of a single coated film with the resistance to chipping properties of the overall coated film from the physical value obtained by measuring the viscoelasticity of the single coated film. SOLUTION: This chipping-resistant coating composition causes the film properties of a single coated film having a relaxation modulus of 5×107 to 1×109 Pa in the range of relaxation time of 10-5 to 105 sec or a relaxation loss tangent of >=1×10-2 Pa in the range of relaxation time of 10-8 to 108 sec in the relaxation spectrum of the coated film obtained by measuring a frequency-temperature dispersion by the use of an automatic viscoelasticity measuring device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a chipping-resistant coating composition.

[0002]

2. Description of the Related Art In the field of the automobile industry, importance has been placed on the problem of coating durability, particularly the problem of deterioration of coating durability due to impact peeling and the progress of corrosion of steel. In a car running on the road, the pebbles flipped up by wheels collide with the coating surface on the outer surface, and the impact causes the coating film to be partially or entirely removed from the car body or the electrodeposition coating film from the electrodeposition coating film Impact delamination phenomena, so-called "chipping", often occur. Due to this phenomenon, the metal surface of the impact portion on the outer surface of the vehicle body is exposed, thereby causing rust and corrosion. In addition, there is a problem that the appearance of the painted surface is significantly impaired due to the peeling off of the top coat.

[0003]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above problems, and as a result, have found that specific coating film physical properties exhibit excellent performance in chipping resistance. The invention has been completed. That is, the present invention

[0004] 1. An independent dynamic viscoelasticity measuring device
Of relaxation of coating film measured from frequency to temperature dispersibility using
In the kutor, the relaxation modulus is 10^-Five-10^Five
5 × 10 in seconds⁷~ 1 × 10⁹Pa or relaxation loss
Tangent is relaxation time 10^-8-10 ⁸1 × 10 in seconds^-2P
a, forming a coating film property in the range of at least
Chipping paint composition,

[0005] 2. Relaxation modulus is 1 × 1 with 1 second relaxation time
0 ⁸ ~8 × 10 ⁸ Pa above the first chipping-resistant coating composition is in the range of,

[0006] 3. The above-mentioned 1 or 2, wherein the coating composition is a curable coating composition containing a polyol resin as a base resin and an amino resin and / or a (block) polyisocyanate compound as a crosslinking agent.
Chipping-resistant coating composition according to,

[0007] 4. The chipping-resistant coating composition according to the above 1, 2, or 3, wherein the polyol resin is an acrylic polyol resin and / or a polyester polyol resin.

[0008] 5. Polyol resin has glass transition temperature
A chipping-resistant coating composition comprising a polyester polyol resin at −20 ° C. to −30 ° C. as a main component,

6. The coating composition is a chipping-resistant coating composition, which is an intermediate coating composition for automobiles,

[0010] 7. An automotive topcoat formed by forming a clear coating on the surface of a base coat having a metallic or pearl finish, wherein the coating forming the basecoat is the above-described chipping-resistant coating composition. A coating composition.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below. In the present invention, a single coating film has a relaxation elastic modulus of 10 ^-5 to 1 in a relaxation spectrum of a coating film whose frequency to temperature dispersibility is measured using an automatic dynamic viscoelasticity measuring device.
0 ⁵ seconds ⁹ range 5 × 10 ⁷ to 1 × 10 in Pa, preferably 1 × 10 ⁸ ~ 1 × 10 ⁹ Pa range, or alleviating the loss tangent in the range of relaxation times ^{10-8 8} seconds 1 × 10 ^-2 P
Any chipping-resistant coating composition falling within a or more can be used without particular limitation.

In the present invention, it is essential that the physical property value of a single coating film formed from the chipping-resistant coating composition is measured under the above-mentioned conditions and the value of the relaxation modulus or the loss tangent falls within the above-mentioned range. Requirements. In order to adjust the physical property value of this single coating film to fall within the above range, it is possible to adjust by changing factors such as the type of the chipping-resistant coating composition, the heat curing temperature, and the heat curing time. is there.

As the chipping-resistant coating composition, for example, the base resin used in the coating composition includes a resin molecular weight, a resin glass transition temperature, and a resin functional group capable of forming a crosslinked coating film by reacting with a crosslinking agent. Examples of the cross-linking agent capable of forming the cross-linked coating film by reacting with the base resin include the type of the cross-linking agent, the type of the functional group, the number of the functional groups,
Those whose molecular weight and the like are appropriately selected so as to fall within the above-mentioned physical properties of the coating film can be used.

[0014] The above-mentioned coating composition, particularly a curable coating composition using an amino resin and a (block) polyisocyanate compound as a cross-linking agent in a polyol base resin, is stable with little variation in the physical properties of the coating film due to baking conditions and the like. It is preferable to use this one because a coated film can be provided. In the present invention, the curing method is not limited to the above-described curing method, and conventionally known curing methods such as a polycarboxylic acid-based resin / polyepoxide crosslinking agent and a polyepoxide-based resin / polycarboxylic acid crosslinking agent are also used. be able to. Further, those curing systems can be used in combination.

The heat curing temperature and the heating time vary depending on the type of the coating composition. However, when an amino resin or a blocked polyisocyanate compound is used as a crosslinking agent, it is usually about 140 ° C. to 200 ° C., preferably about 140 ° C. Fifteen
About 10 minutes to 60 minutes in a temperature range of 0 ° C to 180 ° C,
Preferably, a range of about 20 to 50 minutes is considered sufficient.

When a polyisocyanate compound is used as a crosslinking agent, the temperature is in the range of about 10 to 150 ° C., preferably about 30 to 80 ° C., for about 10 minutes to 24 hours, preferably for about 20 minutes to 10 hours. Is considered to be sufficient.

In the present invention, the single coated film having the above-mentioned physical properties of the coated film may be obtained, for example, by coating a tin plate with a chipping-resistant coating composition and, if necessary, heating to form a coated plate. A film having a thickness of 30 μm from which the chipping resistance is removed is used.

As an automatic dynamic viscoelasticity measuring device, for example, UBM-V4 spectrum meter (trade name, manufactured by UBM Co., Ltd.) can be mentioned. In addition, the measurement condition is measured by changing the frequency from 10 Hz to 900 Hz at a test temperature of −30 ° C. to 180 ° C. by a temperature-frequency dispersion method. From the relaxation spectrum of the coating film obtained by measuring the temperature to frequency dispersion, the relaxation elastic modulus at a relaxation time of 10 ⁻⁵ to 10 ⁵ seconds or the relaxation loss tangent at a relaxation time of 10 ⁻⁸ to 10 ⁸ seconds is determined. Can be calculated (read).

In the present invention, the relaxation modulus is 5 × 10 ^7.
If it is less than Pa, the chipping resistance is inferior and 1 × 10 ⁹ Pa
If the ratio exceeds the above range, the adhesion to the base is reduced. If the relaxation loss tangent is less than 1 × 10 ⁻² Pa, the chipping resistance is also poor.

In the coating composition that can be used in the present invention,
Particularly preferred examples of blending (A) a polyester resin and / or (B) a polyol resin such as an acrylic resin with a (C) amino resin and a (D) (block) polyisocyanate compound as a crosslinking agent are described below. .

(A) The polyester resin has a number average molecular weight of about 200 to 100,000, preferably about 1,000 to 20,000, and an acid value of about 1
-30 KOH mg / g, preferably about 5-20 KOH mg / g, hydroxyl value about 10-200 KOH mg / g, preferably about 20-150 KO
H mg / g polyester resin is preferred.

The polyester resin may be, for example, a polybasic acid (for example, phthalic acid (anhydride), isophthalic acid, terephthalic acid, maleic anhydride (anhydride), pyromellitic acid (anhydride),
2-4 carboxyl groups in one molecule such as (anhydride) trimellitic acid, (succinic anhydride) succinic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, dimethyl isophthalate, dimethyl terephthalate, cyclohexyldicarboxylic acid, adipic acid Or a compound having a carboxylic acid methyl ester group) and a polyhydric alcohol such as ethylene glycol, polyethylene glycol, propylene glycol,
Propylene glycol, neopentyl glycol, 1,6
-2 molecules per molecule such as hexanediol, trimethylolpropane, pentaerythritol, glycerin, tricyclodecanedimethanol, cyclohexyldimethylol, etc.
And an alcohol having from 6 to 6 hydroxyl groups) by an esterification reaction or a transesterification reaction.

In addition to the above, monobasic acids (eg, soybean oil, safflower oil, coconut oil, castor oil, benzoic acid) can be used as required.

(B) The acrylic resin is a copolymer resin containing a hydroxyl group-containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer as monomer components. Examples of the hydroxyl group monomer include ε such as 2-hydroxyethyl acrylate.
-Modified caprolactone is desirable.

The other polymerizable unsaturated monomer may be any monomer that can be copolymerized with the above-mentioned carboxyl group-containing polymerizable monomer, and can be appropriately selected and used according to the required performance. A monomer, an acrylic or cycloalkyl ester having 1 to 18 carbon atoms of acrylic acid or methacrylic acid, a C _{2 to} C ₈ hydroxyalkyl ester of acrylic acid or methacrylic acid, N
One or a mixture of two or more of -substituted acrylamide-based or N-substituted methacrylamide-based monomers can be exemplified.

Although the molecular weight of the acrylic resin (B) is not particularly limited, it is usually a number average molecular weight of 1,000.
Preferably it is in the range of ~ 100,000. Also,
It is also possible to use (A) a polyester resin and (B) an acrylic resin in combination. An example is a composition containing 50% by weight or more of a polyester having a glass transition temperature (Tg, ° C) of -20 ° C or less in the polyol compound in the main component.

The glass transition temperature (Tg, ° C.) is determined as follows. That is, a differential scanning calorimeter (DS)
Using C), a sample pan weighing about 10 mg in a sample pan was heated to 100 ° C. and held for 10 minutes, and then
Cool rapidly to -20 ° C. Thereafter, the temperature is raised at a rate of 10 ° C./min to determine the glass transition temperature.

(C) The amino resin reacts with the resin to
It is for forming a coating film which is cross-linked and cured in a dimension, and specifically includes melamine resins, benzoguanamine resins, urea resins, methylolated products thereof, alkyl etherified products thereof and the like.

(D) The (blocked) polyisocyanate compound includes a polyisocyanate compound and a blocking agent. Examples of the polyisocyanate compound include tolylene diisocyanate, xylylene diisocyanate, bis (isocyanatomethyl) cyclohexane, tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, isophorone diisocyanate, phenylene diisocyanate,
Examples thereof include aromatic, alicyclic, and aliphatic polyisocyanate compounds such as diphenyl diisocyanate.

On the other hand, the blocking agent is one that blocks by adding to the isocyanate group of the polyisocyanate compound, and the blocked isocyanate compound formed by the addition is stable at room temperature and usually about 10%.
It is important that the blocking agent can dissociate and regenerate free isocyanate groups when heated to a temperature in the range of 0 to about 200 ° C.

Examples of the blocking agent satisfying such requirements include lactam compounds such as ε-caprolactam and γ-butyrolactam; oxime compounds such as methyl ethyl ketoxime and cyclohexanone oxime; phenol, para-t-butylphenol and cresol. Phenol compounds; aliphatic alcohols such as n-butanol and 2-ethylhexanol; aromatic alkyl alcohols such as phenyl carbitol and methyl phenyl carbitol; ether alcohol compounds such as ethylene glycol monobutyl ether; In the coating composition, (A) a polyol resin such as a polyester resin and / or (B) an acrylic resin;
(C) The mixing ratio with a crosslinking agent such as amino resin and / or (block) polyisocyanate compound is 1
In 00% by weight, the polyol resin is 95 to 50% by weight, preferably 80 to 60% by weight, and the crosslinking agent is 5 to 50% by weight.
It is in the range of 50% by weight, preferably 20-40% by weight.

The form of the coating composition is not particularly limited, but is most preferably an organic solvent type, but may be a non-aqueous dispersion type, aqueous solution type or water dispersion type using the above-mentioned vehicle component. An extender pigment, a coloring pigment, other paint additives, an epoxy resin, and the like can be added to the coating composition as needed.

Examples of application of the chipping-resistant coating composition of the present invention will be described below.

The chipping-resistant coating composition of the present invention is particularly preferably used as a chipping-resistant coating composition used in the field of automobiles. Further, the chipping-resistant coating composition of the present invention is a coating method in which the chipping-resistant coating is applied to the surface of an object to form an intermediate coating film, and then a top coating material is applied to form a top coating film. Particularly preferred.

The object to be coated is not limited as long as it is a plastic part such as a bumper, a fascia or a fender, or a material such as a metal. Examples include iron, copper, aluminum, tin, zinc and alloys containing these metals, and plating or vapor-deposited products of these metals and alloys, and specifically, passenger cars, trucks, and safari using these. There are bodies of cars, motorcycles, etc. It is preferable that a primer such as polypropylene is applied to the plastic part in advance.

Chipping resistant coating composition: The chipping resistant coating composition of the present invention can be used. The coating composition comprises
It is preferable to apply the coating by spray coating, electrostatic coating or the like. In addition, the coating film thickness is 10 μm to
The heating conditions can be arbitrarily selected depending on the vehicle components.
The temperature is preferably from 170 to 170C, particularly from 120 to 150C, for from 10 to 40 minutes. Alternatively, after coating, an uncoated top coat may be applied, and simultaneously used as a base coat to be cured by heating.

Topcoat paint: This paint imparts cosmetics to the object to be coated. Specifically, the finish appearance (sharpness, smoothness, gloss, etc.), weather resistance (gloss retention, color retention, choking resistance, etc.), chemical resistance, water resistance, moisture resistance, curability, etc. Known coating materials that form an excellent coating film can be used.For example, amino-acrylic resin-based, amino-alkyd-based, and amino-polyester-based resins can be used as the main components of the vehicle. Or a powder coating obtained by dissolving or dispersing the compound in water and / or an organic solvent.

The top coatings which can be used in the present invention are classified into enamel coatings in which metallic pigments and / or coloring pigments are blended with the coatings using the above-mentioned main components of the vehicle, and clear coatings which contain no or little of these pigments. You. And, as a method of forming a top coat using these paints, for example, the following method can be mentioned.

A metallic paint or a metallic paint containing a coloring pigment as necessary or a solid color paint containing a coloring pigment is applied and cured by heating (1.
Metallic or solid color finish by coat 1 bake method).

After applying a metallic pigment or a solid color paint and curing by heating, a clear paint is further applied and then cured again by heating (metallic or solid color finishing by a two-coat two-bake method). Apply metallic paint or solid color paint,
Subsequently, after applying a clear paint, the two paint films are simultaneously cured by heating (metallic or solid color finish by two-coat one-bake method).

It is preferable to apply these top coatings by spray coating, electrostatic coating or the like. In addition, the coating film thickness is 25 μm to 40 μm based on the dry film thickness.
m, in the above, metallic paint and solid color paint are 10 μm to 30 μm, clear paint is 25 μm
m to 50 μm are preferred. The heating condition can be arbitrarily selected depending on the vehicle component, but is preferably from 80 ° C to 170 ° C, particularly preferably from 120 ° C to 150 ° C for 10 minutes to 40 minutes.

[0042]

EFFECTS OF THE INVENTION In the chipping-resistant coating composition of the present invention, pebbles that have been flipped up by wheels collide with the outer plate of an automobile running on a road and collide with the coating film surface, and the top coating film is locally peeled off. It is a coating composition for preventing such a phenomenon. Further, the chipping-resistant coating composition of the present invention is a coating for forming an intermediate coating film provided between an undercoat and a top coating film of an automobile, and a top coating is applied while not being heated, and simultaneously heated and cured. It is preferably used as a base coat paint.

As described above, when the paint of the present invention is applied as an intermediate coating film, pebbles flipped up by wheels collide with the surface of the upper coating film, and the impact energy generated in the top coating film is applied to the intermediate coating film. By relaxing the impact energy given to the top coat by absorption, energy conversion and divergence by the coat, peeling of the top coat can be reduced.

[0044] In ^{addition, 5 × 10 7 ~1 × 10} 9 Pa within a range spectra relaxation modulus relaxation time ^10-5 to ⁵ seconds required to alleviate the impact energy by the pebble
If the relaxation loss tangent is within the range of 1 × 10 ⁻² Pa or more in the range of the relaxation time of 10 ⁻⁸ to 10 ⁸ seconds, a coating film having excellent chipping resistance is formed.

[0045]

EXAMPLES Hereinafter, examples will be described in detail. “Parts” and “%” in Production Examples and Examples are based on weight.

Production Example 1 In a four-necked flask equipped with a stirrer and a rectification column, the following alcohol and acid raw materials were charged, heated and dissolved, and stirring was started. Thereafter, the temperature was raised from 150 ° C. to 230 ° C. over 4 hours, and the generated water was discharged out of the system through the rectification column. Thereafter, the temperature was maintained at 230 ° C. for about 3 hours. When water did not evaporate, the rectification column was replaced with a water separator. Then, 50 g of xylene was added to reflux, and the solvent was separated into water and xylene with a water separator. , Only water was discharged out of the system. The mixture was kept under reflux conditions, and when the resin acid value reached 10 mg / g, heating was stopped. Swarzol 1000 (manufactured by Maruzen Sekiyu KK, trade name, organic solvent) was added, and polyester resin N having a heating residue of 60% was added.
O. 1 was obtained. 1,5-pentadiol 328.3 parts Trimethylolpropane 184.7 parts Hexahydrophthalic acid 298.7 parts Adipic acid 296.3 parts Dehydration amount -108.0 parts.

Production Example 2 By the same operation as in Production Example 1 and by the following formulation, polyester resin NO. 2 was obtained. 1,6-hexanediol 375.9 parts Trimethylolpropane 145.0 parts Isophthalic acid 211.5 parts Hexahydrophthalic acid 196.2 parts Adipic acid 186.0 parts Dehydration amount -114.7 parts Production Example 3 Production Example 1 By the same operation as described above, and the following composition, the polyester resin NO. 3 was obtained. 3-methyl-1,5-pentadiol 250.1 parts Neopentyl glycol 89.0 parts Trimethylolpropane 173.6 parts Isophthalic acid 211.1 parts Hexahydrophthalic acid 195.8 parts Adipic acid 198.0 parts Dehydration amount- 117.5 parts Production Example 4 By the same operation as in Production Example 1 and by the following formulation, polyester resin NO. 4 was obtained. 1,6-hexanediol 51.5 parts Neopentyl glycol 298.1 parts Trimethylolpropane 149.1 parts Hexahydrophthalic acid 201.8 parts Adipic acid 127.5 parts Isophthalic acid 290.0 parts Dehydration amount -118.0 Department

EXAMPLES AND COMPARATIVE EXAMPLES Example 1 A coating material was prepared from the resin obtained in Production Example 1 and the following composition. Polyester resin NO. 1 55 parts (solid content) (Note 1) Niclac MS-35 35 parts (solid content) (Note 2) JR-503 7 parts (Note 3) Carbon HS-100 3 parts and xylene-based solvent are added and solid content is 40%. To adjust the paint. (Note 1) Nikarac MS-35 (manufactured by Sanwa Chemical Co., Ltd., trade name, amino resin, solid content 70%) (Note 2) JR-503 (manufactured by Teika Co., Ltd., trade name, titanium white) (Note 3) Carbon HS-100 (trade name, carbon black, manufactured by Electrochemical Co., Ltd.).

Example 2 A paint was prepared using the resin obtained in Production Example 2 and the following composition. Polyester resin NO. 260 parts (solid content) 30 parts of Niclac MS-35 30 parts (solid content) 7 parts of JR-503 3 parts of carbon HS-100 and a xylene-based solvent were added to adjust the solid content to 40% to prepare a paint.

Example 3 A paint was prepared using the resin obtained in Production Example 3 and the following composition. Polyester resin NO. 365 parts (solid content) Nicalac MS-35 25 parts (solid content) JR-503 7 parts Carbon HS-100 3 parts and a xylene-based solvent were added to adjust the solid content to 40% to prepare a paint.

COMPARATIVE EXAMPLE 1 A paint was prepared using the resin obtained in Production Example 4 and the following composition. Polyester resin NO. 470 parts (solid content) Nicarac MS-35 20 parts (solid content) JR-503 7 parts Carbon HS-100 3 parts and a xylene-based solvent were added to adjust the solid content to 40% to prepare a paint.

Preparation of Test Single Film Using the paints obtained in Examples 1 to 3 and Comparative Example 1, a tin plate was spray-coated to a dry film thickness of 35 μm. . Thereafter, baking was performed at 140 ° C. for 20 minutes to obtain a single film. It shows physical properties measured by a UBM-V4 spectrometer using a temperature-frequency dispersion method and a temperature dispersion method.

Table 1

UBM-V4 spectrum meter (manufactured by UBM Co., Ltd., trade name, automatic dynamic viscoelasticity measuring device) Measurement conditions: temperature to frequency dispersion method temperature dispersion method test temperature −30 ° C. to 180 ° C. test temperature 0 ° C. -200 ° C. Frequency 10 Hz-900 Hz Frequency 11.0 Hz Preparation of performance test plate Chemical conversion treatment Palbond # 3020 (manufactured by Nippon Parker Rising Co., Ltd., zinc phosphate-based) -treated galvanized steel sheet, and cationic electrodeposition paint ELECRON 2000 ( It was electrodeposited with an epoxy polyamide-based cationic electrodeposition paint (manufactured by Kansai Paint Co., Ltd.) and baked at 170 ° C. for 20 minutes to obtain an electrodeposition coated plate having a dry film thickness of about 20 μm.

The coating compositions obtained in Production Examples 1 to 4 were applied to this by spraying so as to have a dry film thickness of about 30 μm, and baked at 140 ° C. for 20 minutes with a drier. Thereafter, a top coat Neoamirac # 6000 White (manufactured by Kansai Paint Co., Ltd., aminoalkyd resin top coat) is applied by spraying so as to have a dry film thickness of about 30 μm, and baked in a dryer at 140 ° C. for 20 minutes. Was.

Table 2 shows the test results of the overall coated plate.

Table 2 Test conditions, evaluation method and chipping resistance Test conditions: Test equipment: QGR gravelometer (Q panel company product) 2. Blown stone: No. 7 crushed stone 3. Amount of stone sprayed: 50 g Air pressure to be blown: 1.96 mPa (about 2 kg /
cm ² ) 5. 5. Temperature during test: about -20 ° C Spraying angle on painted surface: 45 °, 90 ° Evaluation content: only scratches on top-coated surface.
In the case of Δ, scratches on the top coat surface and peeling of the coating film between the coating composition and the raw material are recognized. × indicates that the scratch has almost reached the material. -Nut drop test conditions: A three-class M-4 shaped iron hexagonal nut specified in JIS B-1181 is passed through a 20 mm tube from a height of 2 m and a 45 degree angle to the nut drop direction. 500 g of nuts were dropped on each test plate having the test pieces, and evaluated by the degree of scratches.

Evaluation content: indicates that only the surface of the top coat is scratched. Δ indicates a scratch on the surface of the top coat and peeling of the coating film between the coating composition and the material. × indicates that the scratch has almost reached the material.

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[Procedure amendment]

[Submission date] March 13, 2000 (200.3.1)
3)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004] 1. A single coating film has a relaxation modulus of 10 ⁻⁵ to 10 ^{5 in} a relaxation spectrum of a coating film whose frequency to temperature dispersibility is measured using an automatic dynamic viscoelasticity measuring device.
5 × 10 in the range of seconds ^{7 ~1} × 10 ⁹ Pa, or alleviating the loss tangent is 1 × 10 ^-1 or more in a range of relaxation time ^{10-8 8} seconds
A chipping-resistant coating composition which forms the above range of coating film properties.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

[0011]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below.
In the present invention, a single coating film has a relaxation elastic modulus of 10 ⁻⁵ to 10 ^{5 in} a relaxation spectrum of a coating film in which frequency to temperature dispersibility is measured using an automatic dynamic viscoelasticity measuring device.
5 × 10 ⁷ to 1 × 10 ⁹ Pa in the range of seconds, preferably
The chipping-resistant coating composition is in a range of 1 × 10 ⁸ to 1 × 10 ⁹ Pa or a relaxation loss tangent of 1 × 10 ⁻¹ or more in a range of a relaxation time of 10 ⁻⁸ to 10 ⁸ seconds. Can be used without any particular restrictions.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction contents]

In the present invention, the relaxation modulus is 5 × 10 ^7.
If it is less than Pa, the chipping resistance is inferior and 1 × 10 ⁹ Pa
If the ratio exceeds the above range, the adhesion to the base is reduced. When the relaxation loss tangent is less than 1 × 10 ⁻¹ , the chipping resistance is also poor.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction contents]

[0044] In ^{addition, 5 × 10 7 ~1 × 10} 9 Pa within a range spectra relaxation modulus relaxation time ^10-5 to ⁵ seconds required to alleviate the impact energy by the pebble
Alternatively, by setting the relaxation loss tangent to be in the range of 1 × 10 ⁻¹ or more in the range of the relaxation time of 10 ⁻⁸ to 10 ⁸ seconds, a coating film having excellent chipping resistance is formed.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0053

[Correction method] Change

[Correction contents]

[0053]

[Table 1]

Continued on the front page (72) Inventor Yoshinori Hara 4-171-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa F-term in Kansai Paint Co., Ltd. (reference) 4J038 CG141 CH121 DA112 DD041 DG111 DG191 DG261 DG262 DG302 GA03 KA03 MA13 NA01 NA03 NA11 PB07 PC02

Claims (7)

[Claims] In a relaxation spectrum of a coating film in which a single coating film has been measured for frequency to temperature dispersibility using an automatic dynamic viscoelasticity measuring apparatus, the relaxation elastic modulus is in the range of 10 ⁻⁵ to 10 ⁵ seconds. 5 × 10 ⁷ to 1 × 10 ⁹ Pa, or 1 × 10 ⁻² Pa when the relaxation loss tangent is in the range of the relaxation time 10 ⁻⁸ to 10 ⁸ seconds.
A chipping-resistant coating composition characterized by forming coating film properties in the above ranges. 2. A relaxation elastic modulus of 1 × 10 at a relaxation time of 1 second.
^{2. The} chipping-resistant coating composition according to claim 1, wherein the composition is in the range of ⁸ to 8 × 10 ⁸ Pa. 3. The curable coating composition comprising a polyol resin as a base resin and an amino resin and / or a (block) polyisocyanate compound as a cross-linking agent. 3. The chipping-resistant coating composition according to 1 or 2. 4. The chipping resistant coating composition according to claim 1, wherein the polyol resin is an acrylic polyol resin and / or a polyester polyol resin. 5. The polyol resin has a glass transition temperature of -2.
The chipping-resistant coating composition according to any one of claims 1 to 4, comprising a polyester polyol resin at 0C to -30C as a main component. 6. The chipping-resistant coating composition according to claim 1, wherein the coating composition is an intermediate coating composition for automobiles. 7. An automotive topcoat formed by forming a clear coating film on the surface of a base coat having a metallic or pearl finish, wherein the coating forming the base coat is the above-mentioned chipping-resistant coating composition. The chipping-resistant coating composition according to any one of claims 1 to 6, wherein