JP2940319B2 - Coating composition and coated product obtained by applying the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition and a coated product obtained by applying the coating composition, and more particularly to a coating composition suitable for use in automotive coatings requiring durability and a coating composition obtained by applying the coating composition. Related to painted objects.

[0002]

2. Description of the Related Art Conventionally, paints mainly for polyester resins and acrylic resins have been used as paints for automobiles, but the weather resistance to acid rain and the like is not perfect, and in recent years, Resin-formed products are increasingly used for bumpers, door mirrors, radiator grills, wheel covers, etc. of automobiles, and the color of these resin parts is the same as that of the vehicle body made of metal to improve its design and product appeal. It has been applied for.

[0003] Such a resin component is coated by a so-called wet-on-wet coating in which a base coat 2 is coated with a coating mainly composed of a polyurethane resin and the clear coat 1 is coated in an undried state. 80
Drying at a low temperature of about ° C. has a coating structure as shown in FIG. This polyurethane two-layer coating
Due to the problem of heat resistance of resin parts, baking painting at high temperatures such as a vehicle body with metal members is not possible, so the coating film is inferior in robustness, easily stains due to acid rain, etc. However, there are many problems in durability, and scratches are likely to occur during car washing and the like. In particular, in a dark color coating system, scratches tend to be conspicuous, which is a problem.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a coating composition having excellent weather resistance and durability, and a coated product obtained by applying the same, particularly for use in automobiles. Used for objects that are difficult to bake at high temperatures, such as resin parts that have sufficient weather resistance even when dried at low temperatures.
An object of the present invention is to provide a coating composition having durability and a coated product obtained by applying the coating composition.

[0005]

DISCLOSURE OF THE INVENTION The above objects were attained by using γ-methacryloxypropyltrimethoxysilane as a monomer.
Acrylic polymer (A) 5 containing 0 to 50% by weight
A coating composition comprising 0 to 70 parts by weight, 30 to 50 parts by weight of a silicon compound having an alkoxysilyl group and / or a silanol group (B), and 1 to 10 parts by weight of a curing catalyst (C). Is done.

Another object of the present invention is to provide γ-methacryloxypropyl as a monomer on a coating surface (base coat) to which a coating containing a metal powder and / or a coloring pigment has been applied.
50 to 70 parts by weight of an acrylic polymer (A) containing 20 to 50% by weight of trimethoxysilane, 30 to 50 parts by weight of a silicon compound (B) having an alkoxysilyl group and / or a silanol group, and a curing catalyst ( C) 1
The present invention is also achieved by a coated article characterized in that a coating having a coating composition of 10 parts by weight as a resin solid content is applied.

[0007] Further, the above objects are to provide a top coat clear paint applied to a coated surface (base coat) to which a paint containing a metal powder and / or a color pigment has been applied. 20-5
Acrylic polymer (A) containing 0% by weight of 50 to 7
0 parts by weight, 30 to 50 parts by weight of a silicon compound (B) having an alkoxysilyl group and / or a silanol group,
Further, the present invention is also achieved by a coated article characterized in that a coating having a coating composition comprising 1 to 10 parts by weight of a curing catalyst (C) as a resin solid content is applied.

[0008]

According to the present invention, γ-meta is first used as a monomer.
The scratch resistance of the coating film can be improved by the acrylic polymer (A) containing acryloxypropyltrimethoxysilane . As this monomer, γ-methacryloxy
The acrylic polymer (A) containing the cypropyltrimethoxysilane is the γ-methacryloxypropyl
With lutrimethoxysilane, an alkoxysilyl group for performing a cross-linking reaction is formed at the terminal or side chain of the acrylic polymer, and the cross-linking density of the coating film is increased. Γ-methacryloxypropane when synthesizing an acrylic polymer
The content of Le trimethoxysilane, based on the total component for producing the acrylic polymer, .gamma. Metakurirokishipu
It is 20 to 50% by weight, preferably 30 to 40% by weight, as a propyltrimethoxysilane monomer. γ-methacrylic
When the amount of roxypropyltrimethoxysilane is less than 20% by weight, the crosslink density of the coating film is low, and the scratch resistance is low. On the other hand, when it exceeds 50% by weight, the crosslink density of the coating film is too high, Problems such as the coating film being easily broken due to the residual stress are not preferred.

The other monomer components for producing the acrylic polymer are not particularly limited as long as they are used in ordinary acrylic paints and the like. It is appropriately selected depending on the performance of the paint, the material of the object to be coated, and the like. For example, styrene, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth) ) Butyl acrylate, hexyl (meth) acrylate, (meth)
Ethylhexyl acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate,
(Meth) acrylamide, glycidyl (meth) acrylate and the like are obtained.

The γ-methacryloxypropyl
The acrylic polymer (A) containing trimethoxysilane is used in an amount of 50 to 70 parts by weight in the coating composition. Here, when this amount is less than 50 parts by weight, the crosslinking density tends to be low and the scratch resistance tends to be inferior. On the other hand, when it exceeds 70 parts by weight, the flexibility of the coating film decreases. It is not preferable because it is easily broken.

The silicon compound (B) having an alkoxysilyl group and / or a silanol group in the present invention includes an alkoxysilane compound, a partially hydrolyzed condensate or a reaction product of the alkoxysilane compound, and a mixture thereof. This contributes to improving the adhesion. The compounding amount in the composition is 30 to 50 parts by weight, and if it is less than 30 parts by weight, the crosslink density of the coating film tends to be low and the scratch resistance tends to be inferior. Is not preferred because the flexibility of the coating film becomes too large and the weather resistance tends to deteriorate.

The curing catalyst (C) in the present invention includes:
Organotin compounds, acidic phosphoric acid esters, mixtures or reactants of acidic phosphoric acid esters and amines are preferable, and the compounding amount in the composition is 1 to 10 parts by weight, and when less than 1 part by weight, the compound functions as a catalyst. And the curing reaction of the coating film does not proceed. On the other hand, if it is used in an amount exceeding 10 parts by weight, the reaction proceeds rapidly, and consequently the residual stress is increased, which tends to cause cracking and a poor finished appearance, which is not preferable.

Next, the coated object of the present invention is prepared by first applying a coating containing a metal powder and / or a coloring pigment as a base coat layer to the object to be coated, and applying the coated surface (base coat) or the applied surface. 50 to 70 parts by weight of an acrylic polymer (A) containing 20 to 50% by weight of an alkoxysilane as a monomer of the present invention with respect to a coated product obtained by applying a top coat clear coating to (base coat);
A coating material containing, as a main component, a coating composition comprising 30 to 50 parts by weight of a silicon compound (B) having an alkoxysilyl group and / or a silanol group and 1 to 10 parts by weight of a curing catalyst (C) is applied. It is assumed that. Here, as the object to be coated used in the coated object of the present invention, various resin materials such as polyethylene resin, polypropylene resin, acrylic resin, epoxy resin, polyamide resin, polyurethane resin, rolled steel sheet, cold-rolled steel sheet, stainless steel sheet, Metal materials such as aluminum can be used, and among them, various resin materials are preferable.

[0014]

EXAMPLES Reference Example 1 Preparation of an alkoxysilyl group-containing acrylic polymer (1). A reactor equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen gas inlet tube and a dropping funnel was charged with 50 parts by weight of xylene, and heated to 50 ° C. while introducing nitrogen gas,
10 parts by weight of styrene, n- butyl acrylate 30 parts by weight, 40 parts by weight of methyl methacrylate, .gamma. Metaku Li b <br/> alkoxy mixture of silane 20 parts by weight of 2,2'-azobisisobutyronitrile 1 part by weight was dropped at a constant speed over 5 hours by a dropping funnel.

After the mixture was added dropwise, the mixture was refluxed for 2 hours.
It was cooled naturally to room temperature. Xylene was added to the resin solution to adjust the solid content to 60% by weight to prepare an alkoxysilyl group-containing acrylic polymer (1) solution.

Reference Example 2 Preparation of an alkoxysilyl group-containing acrylic polymer (2). 10 parts by weight of styrene, 20 parts by weight of n-butyl acrylate, 30 parts by weight of methyl methacrylate
A solution of an alkoxysilyl group-containing acrylic polymer (2) was prepared in the same manner as in Reference Example 1 except that the weight part was changed to 40 parts by weight of γ-methacryloxypropyltrimethoxysilane.

Reference Example 3 Preparation of an alkoxysilyl group-containing acrylic polymer (3). 10 parts by weight of styrene, 20 parts by weight of n-butyl acrylate, and 20 parts by weight of methyl methacrylate
A solution of an alkoxysilyl group-containing acrylic polymer (3) was prepared in the same manner as in Reference Example 1, except that the weight part was changed to 50 parts by weight of γ-methacryloxypropyltrimethoxysilane.

Reference Example 4 Preparation of an alkoxysilyl group-containing acrylic polymer (4). 10 parts by weight of styrene, 35 parts by weight of n-butyl acrylate, 40 parts by weight of methyl methacrylate
A solution of an alkoxysilyl group-containing acrylic polymer (4) was prepared in the same manner as in Reference Example 1 except that the weight part was changed to 15 parts by weight of γ-methacryloxypropyltrimethoxysilane.

Example 1 83 parts by weight of an alkoxysilyl group-containing acrylic polymer (1) (A) solution prepared in Reference Example 1, a silicon compound having an alkoxysilyl group and / or a silanol group (B: KR213 [Shin-Etsu Chemical Industrial Co., Ltd.] 50 parts by weight,
1 part by weight of a curing catalyst (C: DR8R [manufactured by Daihachi Chemical Industry Co., Ltd.]), an ultraviolet absorber (Tinuvin 900 [manufactured by Ciba-Geigy]) and a light stabilizer (Tinuvin 144 [manufactured by Ciba-Geigy]) were used as resin solids. , And diluted with xylene to give a sprayable viscosity to prepare a topcoat clear coating. Incidentally, the solution of the above-mentioned alkoxysilyl group-containing acrylic polymer (1) was 83
The amount is the weight of the polymer (1) solution prepared in Reference Example 1, and the amount of the polymer (1) in the solution is 50 parts by weight.

A polyphenylene oxide (PPO) / polyamide (PA) resin material (GTX600 (manufactured by GE)) after degreasing with isopropyl alcohol (IPA) is used.
After applying a liquid urethane paint (SOFLEX 5000 [manufactured by Kansai Paint Co., Ltd.]), the top coat clear paint is applied by a wet-on-wet method, and baked at 80 ° C. for 30 minutes to obtain a test piece having a size of 70 mm × 150 mm. Produced. At this time, the dry film thicknesses of the base coat and the top coat clear were about 15 μm and about 30 μm, respectively.
FIG. 1 shows an outline of the coating structure. In FIG. 1, reference numeral 1 denotes a top coat clear layer, reference numeral 2 denotes a base coat layer, and reference numeral 3 denotes a resin material.

Example 2 Example 1 was repeated except that the alkoxysilyl group-containing acrylic polymer (1) solution of Example 1 was replaced with the alkoxysilyl group-containing acrylic polymer (2) solution prepared in Reference Example 2.
A test piece was prepared in the same manner as in Example 1.

Example 3 Example 1 was repeated except that the solution of the alkoxysilyl group-containing acrylic polymer (1) in Example 1 was replaced with the alkoxysilyl group-containing acrylic polymer (3) solution prepared in Reference Example 3.
A test piece was prepared in the same manner as in Example 1.

Example 4 117 parts by weight of the alkoxysilyl group-containing acrylic polymer (1) solution of Example 1, silicon compound (B) 3 having an alkoxysilyl group and / or silanol group
A test piece was produced in the same manner as in Example 1 except that the weight was changed to 0 parts by weight. The amount of the alkoxysilyl group-containing acrylic polymer (1) solution was 117 parts by weight, but this amount was the amount of the polymer (1) solution prepared in Reference Example 1, and The amount of the combination (1) is 70 parts by weight.

Example 5 117 parts by weight of the alkoxysilyl group-containing acrylic polymer (2) solution obtained in Example 2 and a silicon compound (B) 3 having an alkoxysilyl group and / or a silanol group were used.
A test piece was produced in the same manner as in Example 2 except that the weight was changed to 0 parts by weight.

Example 5 117 parts by weight of the alkoxysilyl group-containing acrylic polymer (3) solution obtained in Example 3 and a silicon compound (B) 3 having an alkoxysilyl group and / or a silanol group were used.
A test piece was produced in the same manner as in Example 3 except that the weight was changed to 0 parts by weight.

Example 7 100 parts by weight of the alkoxysilyl group-containing acrylic polymer (1) solution of Example 1 was used, and a silicon compound (B) 4 having an alkoxysilyl group and / or a silanol group was used.
A test piece was produced in the same manner as in Example 1 except that the weight was changed to 0 parts by weight. The amount of the alkoxysilyl group-containing acrylic polymer (1) solution was 100 parts by weight. This amount is the amount of the polymer (1) solution adjusted in Reference Example 1, and the The amount of the combination (1) is 60 parts by weight.

Example 8 100 parts by weight of the solution of the alkoxysilyl group-containing acrylic polymer (2) of Example 2, silicon compound (B) 4 having an alkoxysilyl group and / or silanol group
A test piece was produced in the same manner as in Example 2 except that the weight was changed to 0 parts by weight.

Example 9 100 parts by weight of the solution of the alkoxysilyl group-containing acrylic polymer (3) of Example 3, and a silicon compound (B) 4 having an alkoxysilyl group and / or a silanol group
A test piece was produced in the same manner as in Example 3 except that the weight was changed to 0 parts by weight.

Example 10 A test piece was produced in the same manner as in Example 1 except that the curing catalyst (C) in Example 1 was changed to 10 parts by weight.

Example 11 In Example 1, a two-part urethane paint (Soflex 5000 [manufactured by Kansai Paint Co., Ltd.]) was applied as a silver metallic base paint, and then a two-part urethane paint (top coat clear) was applied by a wet-on-wet method. After applying Soflex 5000 (manufactured by Kansai Paint Co.)), 8
Bake at 0 ° C. for 30 minutes. Further, a test piece was produced in the same manner as in Example 1 except that the topcoat clear paint prepared in Example 1 was applied by an overcoat clear method and baked at 80 ° C. for 30 minutes. At this time, the dry film thicknesses of the base coat, top coat clear and overcoat clear were about 15 μm, about 30 μm and about 30 μm, respectively. FIG. 2 shows an outline of the coating structure. In FIG. 2, reference numeral 1 denotes a top coat clear layer, reference numeral 2 denotes a base coat layer, reference numeral 3 denotes a resin material, and reference numeral 4 denotes an overcoat clear layer.

Comparative Example 1 The procedure of Example 1 was repeated except that the alkoxysilyl group-containing acrylic polymer (1) solution of Example 1 was replaced with the alkoxysilyl group-containing acrylic polymer (4) solution prepared in Reference Example 4.
A test piece was prepared in the same manner as in Example 1.

Comparative Example 2 117 parts by weight of the solution of the alkoxysilyl group-containing acrylic polymer (4) of Comparative Example 1, and a silicon compound (B) 3 having an alkoxysilyl group and / or a silanol group
A test piece was produced in the same manner as in Comparative Example 1 except that the weight was changed to 0 parts by weight.

Comparative Example 3 100 parts by weight of the solution of the alkoxysilyl group-containing acrylic polymer (4) of Comparative Example 1, and a silicon compound (B) 4 having an alkoxysilyl group and / or a silanol group
A test piece was produced in the same manner as in Comparative Example 1 except that the weight was changed to 0 parts by weight.

COMPARATIVE EXAMPLE 4 67 parts by weight of the alkoxysilyl group-containing acrylic polymer (1) solution obtained in Example 1 was mixed with an alkoxysilyl group and / or
Or a silicon compound (B) 60 having a silanol group
A test piece was produced in the same manner as in Example 1 except that the weight part was changed. The amount of the alkoxysilyl group-containing acrylic polymer (1) solution was 67 parts by weight. This amount was the amount of the polymer (1) solution prepared in Reference Example 1, and the weight in the solution was The amount of coalescing (1) is 40 parts by weight.

Comparative Example 5 133 parts by weight of the alkoxysilyl group-containing acrylic polymer (1) solution of Example 1 was used, and a silicon compound (B) 2 having an alkoxysilyl group and / or a silanol group was used.
A test piece was produced in the same manner as in Example 1 except that the weight was changed to 0 parts by weight. The amount of the alkoxysilyl group-containing acrylic polymer (1) solution was 133 parts by weight. This amount is the amount of the polymer (1) solution prepared in Reference Example 1, and the weight in the solution was The amount of coalescence (1) is 80 parts by weight.

Comparative Example 6 A test piece was prepared in the same manner as in Example 1 except that the curing catalyst (C) in Example 1 was changed to 0.5 part by weight.

Comparative Example 7 A test piece was produced in the same manner as in Example 1 except that the solution of the acrylic polymer (1) containing an alkoxysilyl group in Example 1 was changed to 133 parts by weight.

Comparative Example 8 A test piece was produced in the same manner as in Example 1 except that the silicon compound (B) having an alkoxysilyl group and / or a silanol group in Example 1 was changed to 60 parts by weight.

Test Examples The following tests were performed using the test pieces prepared in Examples 1 to 11 and Comparative Examples 1 to 8 described above. Table 1 shows the test results.

1. Appearance of coating film The test method was performed according to JIS K-5400 6.1. Visual evaluation: ：: good, Δ: normal, ×: bad.

2. Gloss Test method was performed according to JIS K-5400 6.7. 3. Accelerated weather resistance The test method was performed according to JIS K-5400 6.17. Visual evaluation (500 hours); ：: good, Δ: normal, ×: bad.

4. The boiling water test was performed according to JIS K-5400 7.3. Visual evaluation: ：: good, Δ: normal, ×: bad.

5. The acid resistance test method was performed according to JIS K-5400 7.5. Visual evaluation: ：: good, Δ: normal, ×: bad.

6. Scratch resistance Test method: A test piece was stuck on a car with double-sided tape,
Car wash with a commercial automatic car washer five times in a row, after washing with water,
The surface condition of the coating film was visually evaluated. Visual evaluation: ：: good, Δ: normal, ×: bad.

[0045]

[Table 1]

From the results shown in Table 1, the test piece on which the coating film using the coating composition of the present invention was formed showed excellent coating appearance, gloss,
It can be seen that they exhibit accelerated weather resistance, boiling water resistance, acid resistance and abrasion resistance.

[0047]

As described above, the coating composition of the present invention and the coated article obtained by applying the same are used for objects which are difficult to be baked at high temperatures, such as resin materials, and can be dried at low temperatures. Sufficient weather resistance and durability can be obtained.

[Brief description of the drawings]

FIG. 1 is a drawing schematically showing a coating structure of a test piece according to a first embodiment.

FIG. 2 is a drawing schematically showing a coating structure of a test piece according to Example 11.

FIG. 3 is a drawing schematically showing a conventional coating structure.

[Explanation of symbols]

1. Topcoat clear layer, 2. Basecoat layer, 3.
Resin material, 4 ... overcoat clear layer.

Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) C09D 143/04 B05D 7/14 B05D 7/24 302 C09D 183/04 CA (STN) CAOLD (STN) REGISTRY (STN)

Claims (3)

(57) [Claims] 1. A γ-methacryloxypropyl monomer as a monomer.
50 to 70 parts by weight of an acrylic polymer (A) containing 20 to 50% by weight of rutrimethoxysilane, 30 to 50 parts by weight of a silicon compound (B) having an alkoxysilyl group and / or a silanol group, and a curing catalyst ( C) 1
A coating composition comprising from 10 to 10 parts by weight. 2. A coating composition containing a metal powder and / or a coloring pigment is coated with a γ-meth
50 to 70 parts by weight of an acrylic polymer (A) containing 20 to 50% by weight of acryloxypropyltrimethoxysilane, 30 to 50 parts by weight of a silicon compound having an alkoxysilyl group and / or a silanol group (B), and A coated article, characterized by applying a coating having as a resin solid content a coating composition comprising 1 to 10 parts by weight of a curing catalyst (C). 3. A coating material obtained by applying a topcoat clear coating material to a coating surface on which a coating material containing a metal powder and / or a coloring pigment is applied contains 20 to 50% by weight of alkoxysilane as a monomer. Acrylic polymer (A) 50 to 70 parts by weight, silicon compound (B) 3 having alkoxysilyl group and / or silanol group
A coated article, characterized in that a coating having a coating composition of 0 to 50 parts by weight and a curing catalyst (C) of 1 to 10 parts by weight as a resin solid content is applied.