JPH06218320A - Coat structural body - Google Patents

Abstract

PURPOSE:To obtain a coat structural body which has high abrasion resistance, superior water proofness and no fear about the occurrence of an inconvenience such as interlayer separation by ensuring that a first clear layer is composed of specific urethane paint and a second clear layer of acrylsilicone paint. CONSTITUTION:The subject coat structural body 1 is composed of a water ink layer 4 formed in dot-drawn water ink material on an undercoat 3 cold- stilled on the surface of a base 2, and a first clear layer 5 and a second clear layer 6 formed on the water ink layer 4. In addition, the first clear layer 5 is formed with a two-component urethane paint having the ratio of isocyanate for a hydroxyl group and NCO/OH which are higher than 1 and lower than 2, and the second clear layer 6 is formed of an acrylsilicone paint. The two- component urethane paint which constitutes the first clear layer shows an inferior cohesion due to the inhibition of curing of the clear layer 5, if NCO/OH is lower than 1, and shows the deterioration of a finish appearance due to the overacceleration of the curing, if NCO/OH is higher than 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition for drawing a water-based ink material in a dot system on a base coating film formed on the surface of a base material such as an automobile outer plate, and a coating material used therefor. It relates to a composition.

[0002]

2. Description of the Related Art The exterior coating of a vehicle is performed by forming a coating film on the surface of a metal plate, which is a material of the vehicle body, especially an iron plate.
This is performed to prevent corrosion of the metal plate and improve the appearance and design of the vehicle.

Generally, the outer coating of a vehicle is prepared by applying an undercoating such as anion electrodeposition or cation electrodeposition to the surface of a vehicle body which has been subjected to pretreatments such as washing and formation of a phosphoric acid film. It is carried out by applying an intermediate coating by air spraying or electrostatic coating, and forming a top coating by the same method on the intermediate coating. The undercoat is for the purpose of rust prevention, the middle coat is for surface adjustment to improve the finish appearance of the top coat, the protection of the undercoat film from external impact or moisture, the adhesion of the topcoat and the undercoat, etc. The purpose is to add aesthetics and environmental durability.

Further, a desired pattern or letters may be spot-dotted by a dot system on such a coating composition (hereinafter referred to as a base coating) using a water-based ink material to enhance decorativeness and aesthetics. Has been done. Conventionally, when a water-based ink material is drawn on the base coating film 3 by the dot method in this way, as shown in FIG. 2, in order to protect the water-based ink layer 4, for example, NCO / OH of about 2 is used. A clear layer 15 made of a component urethane paint is formed on the upper part of the water-based ink layer 4.

[0005]

However, in such a coating film construction, the clear layer 15 formed on the upper part of the water-based ink layer 4 is inferior in scratch resistance and is clear by car washing with a brush as shown in FIG. There is a problem that scratches are likely to occur on the surface of the layer 15 and the sharpness of a pattern or the like is deteriorated by the occurrence of the scratches.

Further, the durability of the clear layer 15, in particular, the water resistance is inferior, and the adhesion between the water-based ink layer 4 and the clear layer 15 deteriorates with time as shown in FIG. 4, resulting in peeling between the two layers. Could occur.

The present invention has been made in view of the state of the art as described above, and is excellent in scratch resistance when a water-based ink material is drawn on a base coating film by a dot method, and is suitable for car washing or the like. It is an object of the present invention to provide a coating film structure which is free from scratches, has excellent water resistance and is free from problems such as delamination, and a coating composition used therefor.

[0008]

The coating film structure of the present invention for achieving the above object is a water-based ink material formed by drawing a water-based ink material on a base coating film formed on the surface of a substrate in a dot system. An ink layer and a first clear layer and a second clear layer formed on the water-based ink layer are provided, and the first clear layer has a ratio of isocyanate to hydroxyl group (NCO / O).
H) is composed of a two-component urethane paint having a value of more than 1 and 2 or less, and the second clear layer is made of an acrylic silicone paint.

[0009]

The present invention will now be described in detail with reference to FIG. FIG. 1 is a schematic cross-sectional view showing a preferred embodiment of a coating film structure according to the present invention. As shown in the drawing, this coating film structure 1 is formed on a base material 2 which constitutes a body of an automobile or the like. A water-based ink layer 4 formed on the formed base coating film 3,
It is composed of a first clear layer 5 and a second clear layer 6.

In the present invention, the layer structure of the base coating film 3, its material, etc. are not particularly limited. For example, the base coating film 3 is obtained by subjecting the base material 2 to cleaning and pretreatment such as phosphoric acid film formation,
An undercoating film formed by electrodeposition coating such as anion electrodeposition, cation electrodeposition, etc., an intermediate coating film formed by air spraying or electrostatic coating, and an overcoating film formed by the same method. It is configured with a membrane. The surface layer (top coating film) of the base coating film 3 is desired to give a background color having a desired color tone and lightness to the drawing by the dot system using the water-based ink material formed on the upper surface thereof. .

After the base coating film 3 is baked and dried, the base coating film 3 is drawn with a water-based ink material in a dot system using various drawing coating machines or the like to form a water-based ink layer 4. . As the water-based ink material used, a conventionally known material can be used, for example, a rack color (L
AC company) and the like.

In the coating film structure according to the present invention, the first and second clear layers 5 and 6 are formed on such an aqueous ink layer 4, and the first clear layer 5 has a hydroxyl group. Isocyanate ratio (NCO / OH) is 1 <NCO / O
It is formed by a two-component urethane paint in which H <2, preferably 1.2 <NCO / OH ≦ 1.5. That is, in the two-component urethane coating material that constitutes the first clear layer 5, when NCO / OH is 1 or less, the curing of the clear layer is impeded and the adhesion becomes poor.
If / OH is 2 or more, curing is accelerated too much,
This is because the finished appearance deteriorates.

As a two-component urethane paint, NCO /
The OH is not particularly limited as long as it is in the above range, and a catalyst-curable type may be used, but a polyol-curable type is preferably used. Polyisocyanate components for polyol-curable urethane coatings include polyfunctional aromatic isocyanates such as Desmodur L and Coronate L, aromatic diisocyanates such as Desmodur VL, polyfunctional aliphatic and aromatic isocyanates such as Desmodur HL, and Desmodur IL. There are polyfunctional aromatic polyisocyanates, polyfunctional aliphatic isocyanates such as Desmodur N and Coronate HL. As the polyol component, Desmophen 600, 650, 800, 1100, 1200, 1500, 17
00, Multron R-12, R-12, R-18, Daltolac 9, 10, 11, etc. hydroxyl-containing polyester, molecular weight of about 400-4000
There are some diol type or triol type polyethers. These polyisocyanate component and polyol component are used alone or in plural kinds so that NCO / OH falls within the above-mentioned desired range.

The second clear layer 6 on the first clear layer 5 is composed of an acrylic silicone paint. Examples of the acrylic silicon-based paint include an alkylol group (for example, —CH ₂ OH) which is a functional group of a thermosetting acrylic polymer.
-ROH) and an alkoxysilyl group- and / or silanol group-containing compound are condensed to obtain an alkoxysilyl group- and / or silanol group-containing acrylic polymer, and a catalyst. The compound having an alkoxysilyl group and / or a silanol group contributes to the improvement of the adhesiveness of the coating film, and examples of such a compound include an alkoxysilane compound and a partially hydrolyzed condensate or reaction of an alkoxylane compound. And mixtures thereof.

As the catalyst mixed with such an acrylic polymer containing an alkoxysilyl group and / or a silanol group, a mixture or reaction product of an organotin compound, an acidic phosphoric acid ester, an acidic phosphoric acid ester, and an amine is used. It can be illustrated.

In such an acrylic silicon-based coating material according to the present invention, the curing catalyst is an alkoxysilyl group- and / or silanol group-containing acrylic polymer,
11 to 20% by weight, more preferably 11 to 15% by weight
It is desired to be blended in the ratio of. That is, when the amount of the curing catalyst is less than 11% by weight, the curing of the coating film may be hindered and the adhesiveness may be deteriorated. When the amount of the curing catalyst is more than 20% by weight, the curing may be excessively accelerated and the finished appearance tends to be deteriorated. This is because there is a risk that cracks may occur due to the increased stress in the formed coating film.

[0017]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 A test piece (70 × 150 mm) made of a steel plate was pretreated with a zinc phosphate chemical conversion treatment agent (trade name: Granodine DP4000, manufactured by Nippon Paint Co., Ltd.), and then a cationic electrodeposition coating ( Product name: Power Top U-100, manufactured by Nippon Paint Co., Ltd. was used for electrodeposition coating, followed by baking at 180 ° C. for 20 minutes to form an undercoat layer having a thickness of 20 μm. An intermediate coating material (trade name: OP-41, manufactured by Nippon Paint Co., Ltd.) was applied on the undercoat layer and baked at 140 ° C. for 20 minutes to form an intermediate coating layer having a film thickness of 35 μm. Next, top coating (trade name: OG-75 White, Nippon Paint Co., Ltd.)
Manufactured) and baked at 140 ° C for 20 minutes to obtain a film thickness of 3
An overcoat layer of 5 μm was formed. In this way, a base coating film was formed.

A drawing coating machine (trade name:
A water-based ink material (trade name: rack color, manufactured by LAC) was used to form a water-based ink layer by Michelangelo (manufactured by LAC). Then, a two-component urethane paint (NOC / OH = 1.1, a product name: Retan PG60, manufactured by Kansai Paint Co., Ltd.) was applied on the water-based ink layer and baked at 80 ° C. for 20 minutes to form a first clear layer. Formed. Further, on the first clear layer, an acrylic silicon-based paint made of an alkoxysilyl group-containing acrylic polymer (disclosure of a specific trade name or compound name) containing 11% by weight of an organotin compound as a catalyst was applied. , 80 ° C
And baked for 20 minutes to form a second clear layer. The film thickness of each of the first and second clear layers was 30 μm.

The coating film structure obtained was evaluated according to the following procedure. 1) Appearance of coating film: According to JIS K-5400 6.1. Visual evaluation (◯: good, Δ: normal, ×: inferior) 2) Gloss: According to JIS K-5400 6.7. 3) Accelerated weather resistance: According to JIS K-5400 6.17. Test time: 500 hours, visual evaluation (○; good,
Δ: Normal, ×: Inferior) 4) Boiling water resistance: in accordance with JIS K-5400 7.3. Visual evaluation (◯: good, Δ: normal, ×: inferior) 5) Acid resistance: according to JIS K-5400 7.5.
Visual evaluation (○; good, △; normal, ×; inferior) 6) Scratch resistance: A test piece was attached to the vehicle with double-sided tape, and continuously washed five times with a commercially available automatic car wash machine, and the surface of the test piece after washing with water The condition was observed. Visual evaluation (◯: good, Δ: normal, ×: inferior) The results obtained are shown in Table 1.

Example 2 A coating film was prepared and evaluated in the same manner as in Example 1 except that the catalyst amount of the acrylic silicon-based paint was changed to 15% by weight. The results obtained are shown in Table 1.

Example 3 A coating film was prepared and evaluated in the same manner as in Example 1 except that the catalyst amount of the acrylic silicon-based paint was changed to 20% by weight. The results obtained are shown in Table 1.

Example 4 A coating film was prepared and evaluated in the same manner as in Example 1 except that the NCO / OH of the two-component urethane paint was changed to 1.5. The results obtained are shown in Table 1.

Example 5 A coating film was prepared and evaluated in the same manner as in Example 4 except that the catalyst amount of the acrylic silicon-based paint was changed to 15% by weight. The results obtained are shown in Table 1.

Example 6 A coating film was prepared and evaluated in the same manner as in Example 4 except that the catalyst amount of the acrylic silicon-based paint was 20% by weight. The results obtained are shown in Table 1.

Example 7 A coating film was prepared and evaluated in the same manner as in Example 1 except that the NCO / OH of the two-component urethane paint was changed to 1.9. The results obtained are shown in Table 1.

Example 8 A coating film was prepared and evaluated in the same manner as in Example 7 except that the catalyst amount of the acrylic silicon-based paint was changed to 15% by weight. The results obtained are shown in Table 1.

Example 9 A coating film was prepared and evaluated in the same manner as in Example 7 except that the catalyst amount of the acrylic silicon-based paint was 20% by weight. The results obtained are shown in Table 1.

Comparative Example 1 A coating film was prepared and evaluated in the same manner as in Example 1 except that the NCO / OH of the two-component urethane paint was changed to 1.0. The results obtained are shown in Table 1.

Comparative Example 2 A coating film was prepared and evaluated in the same manner as in Example 1 except that the NCO / OH ratio of the two-component urethane paint was changed to 2.0. The results obtained are shown in Table 1.

Comparative Example 3 A coating film was prepared and evaluated in the same manner as in Example 1 except that the catalyst amount of the acrylic silicon-based paint was changed to 10% by weight. The results obtained are shown in Table 1.

Comparative Example 4 A coating film was prepared and evaluated in the same manner as in Example 1 except that the catalyst amount of the acrylic silicon-based paint was 21% by weight. The results obtained are shown in Table 1.

[0033]

[Table 1]

[0034]

According to the coating film structure of the present invention, when a water-based ink layer formed by drawing with a water-based ink material in a dot system is formed on a base coating film, a hydroxyl group is formed on the water-based ink layer. To isocyanate ratio (NCO / OH) is 1
Since the first clear layer made of a two-component urethane paint that is larger and 2 or less and the second clear layer made of an acrylic silicone-based paint are formed, the scratch resistance of the coating film surface is improved and scratches are caused by car washing or the like. The water-soluble ink layer has excellent durability such as water resistance, and the pattern and the like formed by the water-based ink layer can be stably and clearly maintained over time.

The acrylic silicone clear coating composition according to the present invention contains 11 to 20% by weight of a curing catalyst with respect to the alkoxysilyl group- and / or silanol group-containing acrylic polymer. The coating layer thus obtained is transparent, has excellent scratch resistance, and has excellent adhesion to a two-component polyurethane coating film. It can be suitably used for forming a clear layer.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a configuration according to an embodiment of a coating film structure of the present invention,

FIG. 2 is a schematic cross-sectional view showing a conventional example of a coating film structure,

FIG. 3 is a schematic cross-sectional view schematically showing a deteriorated state of a conventional example of a coating film structure,

FIG. 4 is a schematic cross-sectional view schematically showing a deteriorated state of a conventional example of a coating film structure.

[Explanation of symbols]

1 ... Coating film structure, 2 ... Substrate, 3 ...
Base coating film, 4 ... Water-based ink layer,
5 ... first clear layer, 6 ... second clear layer

Claims (3)

[Claims] 1. A water-based ink layer formed by drawing a water-based ink material in a dot system on a base coating film formed on the surface of a base material, and a first clear layer and a second layer formed on the water-based ink layer. A clear layer, wherein the first clear layer has a ratio of isocyanate to hydroxyl groups (NCO / OH) of more than 1 and less than 2 2
A coating film structure comprising a component type urethane coating material and the second clear layer made of an acrylic silicone coating material. 2. The coating film structure according to claim 1, wherein the water-based ink layer, the first clear layer and the second clear layer are formed on a vehicle outer panel top coating film. 3. The method according to claim 1, wherein the acrylic silicon-based paint contains 11 to 20% by weight of a curing catalyst with respect to an alkoxysilyl group- and / or silanol group-containing acrylic polymer. 2. The coating film structure according to item 2.