JP3470598B2 - Transparent paint for top coat - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a paint capable of forming a coating film having excellent transparency and excellent scratch resistance, and more specifically, it is formed on the surface of a molded product by painting, printing or the like. The present invention relates to a transparent coating material useful as a top coat for protecting the formed decorative layer.

[0002]

2. Description of the Related Art Various products, parts or molded products (hereinafter,
For the purpose of enhancing the decorative property or the design property of a molded product or the like), it is general to prescribe a decoration on the surface thereof. However, many decorative layers formed by this formulation tend to have poor physical or chemical properties. For example, when used in an environment where it is exposed to direct sunlight, it has the drawbacks of discoloration and fading, deterioration of the coating film, and poor scratch resistance, and it also has the drawback of poor gloss and fleshness. Therefore, a topcoat paint is overcoated on such a decorative layer to solve the above-mentioned drawbacks.

For example, the hydraulic transfer method, which is known as one of the methods for decorating the surface of a molded article or the like, has a very special process,
Specifically, the step of forming a pattern to be decorated on the water-soluble film by printing, the step of applying a primer (activator) to the print pattern layer on the water-soluble film, the film coated with the primer on the water surface Floating, and a step of spreading it on the water surface, a molded article or the like is pushed into water from above the extended fluidized print pattern layer, and a step of transferring the fluidized print pattern layer to the surface of the molded article by hydraulic pressure, Since the decorative layer is formed through the process of drying and curing the transferred printed pattern layer, the decorative ink used for forming the printed pattern layer has a slightly special composition in order to correspond to these processes. There are many. For this reason, the decorative layer formed is inferior in solvent resistance, weather resistance, glossiness, feeling of holding, etc., and may also be inferior in abrasion resistance. Therefore, the decorative layer formed by this hydraulic transfer method is particularly preferable. Above, it is common practice to topcoat clear paint to remedy these drawbacks.

As the top coat paint in the above-mentioned hydraulic transfer method, a one-pack paint, which forms a paint film by removing a solvent by evaporation, ultraviolet (UV) or electron beam (E)
Generally, a coating that is cured by irradiation of B), a two-component mixed coating that uses an acrylic polyol or a polyester polyol as a main component, and an isocyanate compound as a curing agent is used. It has a drawback that it is inferior in coating film characteristics such as heat resistance, and UV and EB curing type paints have large shrinkage of the coating film at the time of coating film formation, and the substrate cannot cope with this shrinkage, and depending on the material of the applied substrate, The base material itself may be deformed, and the coating film itself becomes too hard, resulting in poor bendability.

On the other hand, the two-component mixed type coating material has no defects such as the one-component type coating material and the UV and EB type curing type coating material, and is excellent in solvent resistance, heat resistance, flexibility and weather resistance. Since a coating film can be formed, it is suitable as a top coat paint for a decorative layer by a hydraulic transfer method, but on the other hand, there is a problem that the surface hardness is poor and the scratch resistance is insufficient. For example, there is a problem that a system using an acrylic polyol as a main agent is generally weak against scratches and a system using a polyester polyol as a main agent is generally weak against scratches.

By the way, as a method for improving the scratch resistance of a coating film, a method is known in which inorganic particles such as silica powder are added to a coating material. However, when silica powder is added to the above-mentioned two-component mixed paint, there is a problem that the formed topcoat coating film itself becomes cloudy, the sharpness of the lower decorative layer is remarkably impaired, and the glossiness also decreases. Therefore, there is a problem that it is not suitable as a paint for protecting the decorative layer.

[0007]

Therefore, the problem to be solved by the present invention is to solve the above-mentioned drawbacks or problems in the conventional top coat paint, and more specifically, to improve the sharpness of the decorative pattern. It has transparency without loss, high glossiness, excellent scratch resistance and scratch resistance, as well as excellent coating properties such as weather resistance, solvent resistance, water resistance, and adhesion. Another object of the present invention is to provide a transparent coating suitable as a topcoat for protecting the above coating, especially a decorative layer formed by the above-mentioned hydraulic transfer method.

[0008]

In order to achieve the above object, plastic
Printed pattern layer formed on the surface of the molded product by the hydraulic transfer method
A transparent coating material for a top coat for protecting the decorative layer, wherein the coating film forming component of the transparent coating material is a synthetic resin, and 100 parts by weight of the coating film forming component of the transparent coating material is powdered boric acid. The problem can be solved by using a clear coating for a top coat containing 0.5 to 20 parts by weight of aluminum .

Further, in the transparent coating material for top coat of the present invention, the coating film forming component is a polyurethane resin formed by the reaction of at least one polyol compound selected from acrylic polyol and polyester polyol with an isocyanate compound. Is preferred.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the transparent coating material for topcoat of the present invention (hereinafter referred to as the topcoat coating material of the present invention), the synthetic resin as a coating film forming component is not particularly limited and is commonly used in the coating field. A variety of synthetic resins can be used. Specific examples thereof include acrylic resin, polyester resin, polyurethane resin, polystyrene resin, epoxy resin, polyamide resin, melamine resin, silicone resin, and fluororesin. These resins may be used alone or in combination of two or more. Is also good.

Among the synthetic resins exemplified above, flexibility,
It is preferable to use an acrylic / urethane-based synthetic resin having excellent weather resistance and the like. In particular, an acrylic obtained by reacting the following polyol component (at least one selected from 1 and 2) with a polyisocyanate compound (3) -Urethane type synthetic resin is preferable. (1) Acrylic polyol, for example, aliphatic, alicyclic or aromatic vinyl-based monomer, hydroxyl group-containing acrylic monomer (for example, hydroxyethyl acrylate,
Resin etc. which are obtained by copolymerizing hydroxyethyl methacrylate and the like). (2) Polyester polyol, such as saturated polyester resin. (3) Isocyanate compound, for example, isocyanurate type polyisocyanate, burette type polyisocyanate, urethane type polyisocyanate, hexamethylene diisocyanate and the like. Such an acrylic / urethane synthetic resin is preferably used in combination with aluminum borate because good coating properties such as excellent scratch resistance can be obtained while maintaining particularly good transparency.

Form of aluminum borate used in the present invention
The shape is a granular material (powder) in consideration of coating workability . The particle size is not particularly limited, but generally 30
It is less than or equal to μm, preferably less than or equal to 10 μm. The amount of aluminum borate added is 0.5 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the coating film forming component in the synthetic resin. If the amount added is less than 0.5 parts by weight, the effect of improving scratch resistance is small, and if it exceeds 20 parts by weight, the transparency of the coating film formed decreases, and the viscosity of the coating increases to improve the coating properties. Get inferior.

The above-mentioned aluminum borate generally has a large specific gravity and may settle in a liquid coating material, so that it is preferable to use an antisettling agent together. The anti-settling agent that can be used is not particularly limited, and various anti-settling agents that are commonly used in the field of coating materials, such as polymer copolymers, polyamide compounds, polycarboxylic acid compounds, and the like can be used. The anti-settling agent is aluminum borate 100
The amount is preferably 1 to 50 parts by weight, and particularly preferably 5 to 20 parts by weight. If the amount of the anti-settling agent used is less than 1 part by weight, the anti-settling effect is small, and if it exceeds 50 parts by weight, the coating composition is remarkably thickened, which makes the coating operation difficult.

In the method for producing the coating composition of the present invention, a synthetic resin as a coating film forming component is mixed with an appropriate solvent such as toluene,
It is dissolved in xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, acetone, ethyl alcohol, isopropyl alcohol, etc., and this resin solution is mixed with aluminum borate and, if necessary, a prescribed amount of an antisettling agent and stirred. It can be obtained by homogenizing the same. At that time, if necessary, various additives known in the coating industry, for example, a leveling agent, an ultraviolet absorber, an antifoaming agent, a reaction accelerator, a tackifier and the like may be added in conventional amounts. Further, as long as the transparency is not impaired, a pigment,
There is no problem in adding a coloring agent such as a dye.

[0015]

As a method for coating the top coat paint of the present invention, spray coating is preferable, but the present invention is not limited to this, and known coating methods such as brush, roller, curtain coat, flow coat and dip coat can be applied. . Further, the base material such as a molded article having a decorative coating film to which the present invention topcoat paint is applicable is not particularly limited, and various plastics, wood, metal, paper,
Any of ceramic, glass, ceramics, etc. may be used.

[0017]

EXAMPLES Specific examples of the present invention will be described in detail by the following examples. In addition, all of the formulation examples described below represent parts by weight. Example 1 a. Composition of main agent (blends the following components and stirs and mixes them uniformly) Acrylic polyol (Toray Co., Ltd., Cotax LH-615) 30 parts Acrylic polyol (Toray Co., Ltd., Cotax LH-635) 50 Part Ultraviolet absorber (Ciba Geigy, Tinuvin 1130) 2 parts Solvent (xylene / PMA = 7/3) 50 parts Aluminum borate (Shikoku Kasei Co., Arbolite PF-08) 5 parts Anti-settling agent (Kusumoto Kasei Co., Ltd.) , Disparlon 6900-20XN) 0.2 parts b. Composition of curing agent (using Desmodur 0831 manufactured by Sumitomo Bayer Urethane Co., Ltd. as the polyisocyanate compound) c. Composition of diluted thinner (mixing the following components) MIBK 20 parts Petroleum solvent (manufactured by Yamaichi Chemical Industry Co., SS-1500) 40 parts DIBK 40 parts The above-mentioned main agent (a), curing agent (b), diluted thinner ( c)
Were mixed in a ratio of 100 parts: 12 parts: 40 parts to obtain the top coat paint of the present invention.

The top coat paint obtained above was spray-painted on the surface of the decorative layer on which a printed pattern was formed by a hydraulic transfer method so as to have a dry coating film thickness of about 20 microns.
The resulting top coat coating film was dried for 30 minutes at a temperature of 30 minutes and evaluated by the following test method. The evaluation results are shown in Table 1 below.

[0019]Test method and evaluation criteria (1) Transparency: Visuality of the printed pattern of the decorative layer by visual observation
Evaluate with. (2) Surface gloss: JIS K 5400 “7.6 specular light
60 degree specular gloss is measured according to "Sawa degree".(3) Scratch resistance: JIS K 5401 "Lead for coating film"
The strength of the coating film is measured using a "scratch tester". that time
The test conditions are: core length 3 mm, angle with coating surface 45
Degree, load 1 kg, scratching speed 0.5 mm / min, scratching length
3 mm in length, and the pencil used was Mitsubishi Uni.(4) Scratch resistance: Using a traverse type tester, load 1
kg / 9cm^Two, Steel wool 000, 5 round trips
Abrasion the coating surface under the test conditions to increase the gloss before and after the test.
Record(2)The measurement is performed in the same manner as above, and the residual rate of gloss is evaluated.

Example 2 Acrylic resin paint (Recrack # 72, manufactured by Fujikura Kasei Co., Ltd.)
A base compound was prepared by adding 100 parts of the same 5 parts of aluminum borate as used in Example 1 and 0.2 part of an anti-settling agent to 100 parts of the base compound and diluted thinner 1 of Example 1.
20 parts of the mixture was mixed to obtain a top coat paint of the present invention. Evaluation was performed in the same manner as in Example 1, and the evaluation results are shown in Table 1.

Comparative Example 1 A top coat coating composition of the present invention was prepared by the same formulation as in Example 1 except that the amount of aluminum borate was changed to 15 parts in the composition of the main agent in Example 1 and evaluated in the same manner. . The evaluation results are shown in Table 1. Comparative Example 2 A topcoat paint was prepared in the same formulation as in Example 1 except that the amount of aluminum borate was changed to 0.15 parts in the composition of the main agent in Example 1, and the same evaluation was performed. The results are shown in Table 1. Comparative Example 3 A topcoat coating composition was prepared in the same manner as in Example 1 except that 0.5 part of colloidal silica was used instead of 5 parts of aluminum borate in the composition of the main agent in Example 1, and the same evaluation was performed. Comparative Example 4 A coating material for a top coat was prepared and evaluated in the same manner as in Example 1 except that 1.5 parts of acrylic resin beads were used in place of aluminum borate in the composition of the main agent in Example 1. Comparative Example 5 A topcoat paint was prepared without using aluminum borate in the composition of Example 2 and evaluated in the same manner as in Example 1.

[0022]

[Table 1]

[0023]

EFFECTS OF THE INVENTION The top coat paint of the present invention has a high gloss, since it does not impair transparency at all because it contains a specific amount of aluminum borate in a paint containing a synthetic resin as a film forming component. Also, a coating film having excellent scratch resistance can be obtained. Therefore, it is extremely useful as a top coat paint for protecting a decorative layer having poor coating film properties.

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Claims (2)

(57) [Claims] 1. A hydraulic transfer method applied to the surface of a plastic molded product.
A transparent coating material for a top coat for protecting a decorative layer which is a printed pattern layer formed by the method, wherein the coating film forming component of the transparent coating material is a synthetic resin, and 100% by weight of the coating film forming component of the transparent coating material. parts with respect to, powdered aluminum borate 0.5 to 20 parts by weight clearcoat topcoat to feature that it contains. 2. The coating film forming component is a polyurethane resin formed by the reaction of at least one polyol compound selected from acrylic polyol and polyester polyol with an isocyanate compound.
Transparent paint for the top coat described.