JP2003313492A - Thermosetting coating material, method for coating therewith, and object coated therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosetting coating material capable of forming a thick coating film which exhibits both rust-preventive power and beautifullness, and to provide a method for coating an object therewith. <P>SOLUTION: A metallic material 1 of an object to be coated is subjected to a chemical treatment or a mechanical treatment to give thereto a surface condition suitable for coating and is coated with the thermosetting coating material containing 30-45 wt.% alkyd resin, 5-20 wt.% melamine resin, an epoxy resin, aluminum phosphate and/or zinc phosphate, barium sulfate, and calcium carbonate and having a barium sulfate/calcium carbonate ratio of 4:1 to 1:1 to form a 10-160 μm thick thermosetting coating material film 2, which is cured by heating at 110-160°C for 10-60 min to coat the object. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting coating material, a coating method thereof and a coated product thereof.

[0002]

2. Description of the Related Art The conventional method for coating the metal part of a coated article is
After performing the pretreatment as described in Patent Document 1, a coating film was formed with an undercoat paint having an anticorrosive property composed of an epoxy resin system, an epoxy resin, a melamine resin and the like. After the coating film was formed, when it was a thermosetting type, it was heat-cured at 120 ° C. or higher. After that, a coating film was formed, if necessary, with the same type of intermediate coating composition that was compatible with the undercoat coating, and in the case of the thermosetting type, it was heat-cured at 120 ° C. or higher. Furthermore, a coating film was formed with a thermosetting melamine resin-based enamel topcoat paint that gives an aesthetic appearance, and was heat-cured at 120 ° C. or higher.

[0003]

[Patent Document 1] Japanese Patent Laid-Open No. 11-241048

[Problems to be Solved by the Invention] For the coating of the metal part of the coating material, use an undercoat paint with a focus on rust prevention, a topcoat paint with a focus on aesthetics, and separate paints for rust prevention and aesthetics. I had to prepare. Further, in some cases, it was necessary to apply an intermediate coating material as a base to give the aesthetic appearance of the top coating while also having anticorrosive properties.
Every time the undercoat paint, the intermediate paint, and the topcoat paint were applied, heat curing had to be performed in order to obtain long-term coating durability. In addition, when a coating of 80 μm or more is carried out in a single coating, a solvent is boiled during curing to cause a side effect (pinhole), resulting in a coating defect.
Who is more likely to cause it. It is an object of the present invention to provide a method for coating a coated article and a thermosetting coating material that have both anticorrosive power and aesthetics and can form a thick coating film.

[0004]

To achieve the above object, the present invention according to claim 1 provides an alkyd resin of 30 to 45% by weight, a melamine resin of 5 to 20% by weight, an epoxy resin and an anticorrosive pigment.
It is a thermosetting paint containing 0.2 to 1.5% by weight. By containing 0.2 to 1.5% by weight of the rust preventive pigment, a coating film having a rust preventive effect can be formed. Further, the present invention of claim 3 is a thermosetting coating material which also contains barium sulfate and calcium carbonate. Barium sulphate and calcium carbonate can form thick coatings.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. (Embodiment 1) FIG. 1 is a sectional view showing a coating system for metallic materials according to Embodiment 1 of the present invention. Pickled steel plate and SPC
In order to make the metal material 1 such as C material a surface state suitable for coating, a chemical pretreatment such as a zinc phosphate coating or a mechanical pretreatment such as sandblasting is performed to make the surface state suitable for coating. After that, the thermosetting coating film 2 of the thermosetting coating material (A) is formed to a thickness of 10 to 160 μm, and heated and cured at 110 to 160 ° C. for 10 to 60 minutes. The thermosetting coating (A) is a thermosetting coating composed of alkyd resin, melamine resin, epoxy resin, aluminum phosphate or / and zinc phosphate, barium sulfate and calcium carbonate. The components of the thermosetting coating material (A) are shown in Table 1.

[0005]

[Table 1] By adding aluminum phosphate or / and zinc phosphate which is a rust preventive pigment, the thermosetting coating material (A) can improve the rust preventive performance without impairing the aesthetic appearance and durability. In addition, the thermosetting coating material (A) stabilizes a coating film having a thickness of 50 μm or more by one coating by adjusting the mixing ratio of barium sulfate and calcium carbonate to 4: 1 to 1: 1 (weight ratio). You can get the quality you want. Among them, the most stable quality can be obtained when the ratio is approximately 2: 1.
By adjusting the viscosity of the paint with an organic solvent thinner to 35-55 seconds and performing spray coating, it is possible to further reduce sagging and form a thick film thickness, and to prevent coating defects such as armpits (pinholes). Coating can be performed without causing Since the thermosetting coating material has various necessary functions, it is important to balance the selection of basic materials and the composition. From a thin film thickness of 10 μm to a thick film thickness of 160 μm,
The stable quality can be obtained even when the thermosetting conditions are set to a constant 110 to 160 ° C. for 10 to 60 minutes because of the blending balance of the resins. In particular, the blending ratio of alkyd resin and melamine resin is an important point. If the alkyd resin content exceeds 45% by weight, the flexibility (impact resistance) is adversely affected, and if the alkyd resin content is less than 30% by weight, it softens. However, the corrosion resistance is affected. In particular, the most stable quality can be obtained when the alkyd resin is 35 to 40% by weight and the melamine resin is 10 to 16% by weight.

The above-mentioned thermosetting coating material (A) was subjected to the following tests. 1. Initial physical property test (1) Hardness: JIS K5400 Pencil scratch test (2) Adhesion: ASTM 3359 (cross-cut or cross-cut + adhesive tape) 50 μm or less (method B), 50 to 12
5 μm (B method), 125 μm or more (A method) (3) Impact resistance: JIS K5400 impact resistance test (Dupont type) 60 μm or less, 60 to 100 μm, 100 μm
Above 2. Durability test 2-1 Salt spray test: JIS Z2371 Appearance and secondary physical properties after 1000 hours of salt spray test (a) Appearance (1) Hardness: JIS K5400 Pencil scratch test (2) Adhesion: ASTM 3359 (Checkerboard or Cross cut + adhesive tape) 50 μm or less (method B), 50 to 12
5 μm (B method), 125 μm or more (A method) (3) Impact resistance: JIS K5400 impact resistance test (Dupont type) 60 μm or less, 60 to 100 μm, 100 μm
2-2 Moisture resistance test: JIS K5400 humidity resistance test (condensation occurs at 50 ° C, 98% RH) Appearance and secondary physical properties after 1000 hours (a) Appearance (1) Hardness: JIS K5400 Pencil scratch test (2) Adhesion : ASTM 3359 (cross-cut or cross-cut + adhesive tape) 50 μm or less (method B), 50 to 12
5 μm (B method), 125 μm or more (A method) (3) Impact resistance: JIS K5400 impact resistance test (Dupont type) 60 μm or less, 60 to 100 μm, 100 μm
2-3 Sulfurous acid gas test: 20 ppm, 40 ° C., 90% R
H, Appearance after 1000 hours of execution and secondary physical properties (a) Appearance (1) Hardness: JIS K5400 Pencil scratch test (2) Adhesion: ASTM 3359 (cross-cut or cross-cut + adhesive tape) 50 μm or less (method B), 50-12
5 μm (B method), 125 μm or more (A method) (3) Impact resistance: JIS K5400 impact resistance test (Dupont type) 60 μm or less, 60 to 100 μm, 100 μm
2-4 chlorine gas test: 1 ppm, 40 ° C., 90% RH,
Appearance after 1000 hours and secondary physical properties (a) Appearance (1) Hardness: JIS K5400 Pencil scratch test (2) Adhesion: ASTM 3359 (cross-cut or cross-cut + adhesive tape) 50 μm or less (method B), 50 to 12
5 μm (B method), 125 μm or more (A method) (3) Impact resistance: JIS K5400 impact resistance test (Dupont type) 60 μm or less, 60 to 100 μm, 100 μm
Above 2-5 weather resistance test: JIS K5400 accelerated weather resistance (sunshine carbon arc lamp type) appearance after 500 hours and secondary physical properties (a) appearance (1) hardness: JIS K5400 pencil scratch test (2) adhesion: ASTM3359 (Cross-cut or cross-cut + adhesive tape) 50 μm or less (method B), 50 to 12
5 μm (B method), 125 μm or more (A method) (3) Impact resistance: JIS K5400 impact resistance test (Dupont type) 60 μm or less, 60 to 100 μm, 100 μm
Table 2 shows the results of these tests.

[0007]

[Table 2] It can be seen from Table 2 that the thermosetting coating material (A) can provide a high quality coating film having both functions of rust prevention and aesthetics. In addition, since it also has an intermediate coating function such as adhesion, smoothness, and thick film function, it is possible to apply an undercoat / intermediate coat / top coat with a single coating. From these, acrylic-modified alkyd resin, water-soluble melamine resin, epoxy resin, color pigments, since the top coating is performed with a water-based paint composed of additives and diluents, both antirust and aesthetics,
A coating film with excellent durability and stable quality can be obtained. (Embodiment 2) FIGS. 2 and 3 are sectional views showing a coating system of a metal material according to Embodiment 2 of the present invention. Pickled steel plate and S
Metal material 1 such as PCC material is subjected to chemical pretreatment such as zinc phosphate coating and mechanical pretreatment such as sand blasting in order to obtain a surface state suitable for coating.
After making the surface state suitable for coating, the thermosetting coating film 2 of the thermosetting coating material (A) is formed to a thickness of 10 to 150 μm. Furthermore, in order to obtain high anticorrosion performance, after forming the thermosetting coating film 2, the room temperature drying type urethane resin coating,
A room temperature dry type coating film 3 of 5 to 100 μm is formed with a room temperature dry type coating material such as high solid lacquer or acrylic lacquer. Alternatively, after forming the thermosetting coating film 2 having a thickness of 10 to 150 μm with the thermosetting coating material (A), a room temperature drying type coating material such as a retin resin coating material or an adhesion-improving binder coating material is used in an amount of 3 to 150 μm.
After forming the adhesion-improving binder coating film 4 having a thickness of .mu.m and then forming the adhesion-improving binder coating film 4, a room temperature drying type urethane resin coating, a room temperature drying type paint such as a high solid lacquer or an acrylic lacquer, and a room temperature of 5 to 100 .mu.m A dry type coating film 5 is formed. Tables 3 to 6 show the components of the retan resin paint, the adhesion improving binder paint, the high solid lacquer and the acrylic lacquer.

[0008]

[Table 3]

[Table 4]

[Table 5]

[Table 6] The same test as the thermosetting paint (A) was carried out on the ones coated with the thermosetting paint (A) and then the ordinary temperature dry urethane resin coating and general coating such as high solid lacquer and acrylic lacquer. . The results of these tests are shown in Table 7.

[0009]

[Table 7] From Table 7, the thermosetting coating material (A) has excellent adhesive force due to the action of the epoxy resin of the thermosetting coating material (A). Further, the thermosetting coating (A) has excellent anticorrosion performance, so that it can be applied as an undercoat of urethane resin, high solid lacquer and acrylic lacquer which are dry at room temperature. Since it also has performance, there is little unevenness on the painted surface, and you can get an aesthetically beautiful finished surface. The coating of the thermosetting paint (A) can be applied to steel plates and SPCC material parts which are metal materials housed in a switchboard / control panel, and can be used for steel plates, SPCC materials, and aluminum materials that compose vehicles. Also applicable to stainless steel.

[0010]

EFFECTS OF THE INVENTION According to the present invention, a thermosetting paint having both anticorrosive power and aesthetic appearance and capable of forming a thick coating film is used for coating, so that the number of steps and working time can be reduced and workability can be improved. You can

[Brief description of drawings]

FIG. 1 is a sectional view showing a coating system of a metal material according to Embodiment 1 of the present invention.

FIG. 2 is a sectional view showing a coating system for metallic materials according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a coating system for metallic materials according to a second embodiment of the present invention.

[Explanation of symbols]

1 ... Metal material 2 ... Thermosetting coating film 3, 5 ... Room temperature dry type coating film 4 ... Adhesion improving binder coating

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4D075 CA02 CA04 CA13 CA32 CA33                       DA06 DB02 DB04 DB07 DC11                       DC18 EA07 EA19 EB32 EB33                       EB36 EB56 EC01 EC15 EC54                 4J038 DA162 DB002 DD231 HA286                       HA376 HA416 KA05 KA08                       MA07 MA10 NA01 NA03 PA19                       PC02

Claims (7)

[Claims] 1. Alkyd resin 30 to 45% by weight, melamine resin
A thermosetting coating material, which comprises 5 to 20% by weight, an epoxy resin and 0.2 to 1.5% by weight of an anticorrosive pigment. 2. The thermosetting paint according to claim 1, wherein the anticorrosive pigment contains at least one of aluminum phosphate and zinc phosphate. 3. The thermosetting coating composition according to claim 1, which contains barium sulfate and calcium carbonate. 4. The thermosetting paint according to claim 3, wherein the compounding ratio of the barium sulfate and the calcium carbonate is 4: 1 to 1: 1. 5. Alkyd resin 35-40% by weight, melamine resin
10 to 16% by weight, epoxy resin, aluminum phosphate or zinc phosphate 0.2 to 1.5% by weight, barium sulfate and calcium carbonate are contained, and the compounding ratio of the barium sulfate and the calcium carbonate is approximately 2: 1. Characteristic thermosetting paint. 6. A coating method, which comprises applying the thermosetting coating composition according to any one of claims 1 to 5 to a metal part of a coated article. 7. A coated article, characterized in that a metal member is coated with the thermosetting coating composition according to any one of claims 1 to 5.