JPS63218281A - Crack painting process - Google Patents

Abstract

PURPOSE:To prepare coated surface having no wrinkles and having high design value, by executing undercoating on an article to be coated with a photosetting paint which is not set by heating, then applying a rapid hot-curing cracking paint to the article while the photosetting paint is uncured, and forming cracks by heating, and causing photosetting thereafter. CONSTITUTION:A thermally uncured photosetting paint 2 consisting primarily of methyl methacrylate, etc. is undercoated on an article 1 to be coated, then a rapid hot-curing cracking paint 3, for example, nitrocellulose contg. stearate, etc. is applied thereto while the photosetting paint is yet uncured. After forming cracks 4 in the coating film formed by the cracking paint 3 by heating, the coating film of the photosetting paint 2 is hardened by irradiating with light energy. As a result, a coated surface contg. no wrinkles but having high design value is formed. Furthermore, since the photosetting paint forming hard coating film is used as the undercoat, the strength of the coating film as a whole is elevated, and the production efficiency is improved.

Description

[Detailed Description of the Invention] [Prior Art] Cracking coating, which has been conventionally used for building materials, etc., involves coating a material 11 with a heat-drying undercoating paint, and applying this coating film 12.
After curing, a cracking paint was applied and heated to form cracks in the coating film 13 made of the cracking paint. However, in this method, a cracking paint that has an affinity for the cured undercoat film is applied to form a paint film, and cracks are forcibly formed in this paint film. A relatively soft film is required, and as a result, many wrinkles 15 remain within the crack grooves 14, and when viewed up close, the appearance is not very good. It was not possible to apply it to everyday items such as containers.

Furthermore, as a result of the crack formation, a coating film 12 of the undercoat appears on the surface of the groove 14, but as mentioned above, conventional undercoat paints have a soft coating and are relatively easily scratched. Usually, a thick clear coat is applied after crack formation to improve scratch resistance and appearance.

[Object of the present invention]

The object of the present invention is to eliminate the drawbacks of the prior art as described above, and to form a painted surface that is completely free of wrinkles and has an extremely high design quality, as shown in FIG.

[Summary of the invention]

In the present invention, as an undercoat for a cracking paint, a photo-curable paint that causes almost no thermal reaction, such as an ultraviolet-curable paint containing methyl methacrylate as a main component, is applied to an object to be coated 1 to form a coating film 2. While uncured,
In contrast to undercoat paints, we apply cracking paints that dry quickly under heat and have a very high shrinkage rate, causing the paint film itself to crack when heated. By heating for about 5 to 10 minutes to form cracks 4 in the coating film 3 made of cracking paint, a highly decorative crack pattern is formed, as if the film were cracked on water. , and then apply further light-curing paint on top of this if necessary.

Finally, the photocurable coating film is cured by irradiation with light energy.

Although it is a two-step process, the irradiation with light energy is performed after the cracking coating film is formed, and then the photocurable paint is applied again, and the overlay is irradiated with light energy to harden the paint.

Generally, the thickness of the undercoat film is about 5 to 40μ, especially 10 to 2
0 μ is preferable, and the thickness of the cracking coating is about 5 to 30 μm.
When μ is thin, fine cracks occur, and when it is thick, large cracks occur.

[Undercoat paint of the present invention]

The undercoat paint of the present invention is a light-curable paint that does not substantially cure due to heat and can maintain a state in which the paint film can move freely no matter how much it is heated. Lines etc. are used.

The main components of the undercoating paint of the present invention usually consist of oligomers, monomers, and sensitizers. Preferred combinations of oligomers and monomers include acrylic resin oligomers and acrylic monomers, acrylic resin oligomers and acrylic monomers, and acrylic resin oligomers and acrylic monomers. Monomer, acrylated alkyd resin and acrylic monomer, polyester acrylate and acrylic monomer, polyether acrylate and acrylic monomer,
There are acrylated epoxy resins and acrylic monomers, acrylated polyurethane and acrylic monomers, acrylated spirane resins and acrylic monomers, and acrylic monomers include acrylic acid and methacrylic acid.

Ethacrylic acid or esters thereof are typical. Further, as the sensitizer, suitable ones can be selected singly or in combination from conventionally known photosensitizers depending on the heating conditions of the post-process, the nature of the light energy used, etc. However, typical examples include carbonyl compounds such as benzoin, benzoin methyl ether,
Benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, acetophenone, 2,2-jethoxyacetophenone, benzophenone, Pyp'-bismethylaminophenone, thioxanthone, 2-chlorothioxanthone, diacetyl, benzyl, α-haloketone, 2-chloro anthraquinone, etc.; organic peroxides such as benzoyl peroxide, di-t-peroxide;
Butyl, etc.; Azo compounds such as azobisisobutyronitrile, 2,2'-azobispropane, m,m'-azoxystyrene, etc.; Halides such as carbon tetrabromide, α-
Bromonaphthalene, 1-gloromethylnaphthalene, etc.; sulfur compounds, diphenyl disulfide, dibenzyl disulfide, dibenzothiazoyl disulfide, tetramethylthiuram disulfide, etc.

In addition, reactive diluents that are conventionally used in these photocurable coatings as diluents and crosslinking agents for oligomers or resins can also be used. Representative examples thereof include 2-ethylhexyl acrylate, cyclohexyl acrylate, and butoxyethyl acrylate.

Neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, sheatool 2,2-diacrylate, polyester diacrylate, unsaturated polyester resin, vinyl There are ester resins, etc.

It goes without saying that the photocurable coating material of the present invention may contain various conventional additives, such as stabilizers, ultraviolet absorbers, solvents, leveling agents, etc., as needed.

[Cracking paint of the present invention]

The cracking paint of the present invention has the property that it can be coated with the above-mentioned photocurable undercoat paint while it is still wet, and that the paint film shrinks and hardens quickly by heating at a relatively low temperature. This is a paint that has the property of forming cracks.

A typical example is a paint containing nitrocellulose as the main component as a resin component and stearate as a crack forming agent. Specific examples of stearates include calcium stearate, lead stearate, zinc stearate, and the like.

[Coated object of the present invention]

The object to be coated according to the present invention is completely arbitrary and is not limited in any way, and examples include plastics, metals, ceramics, wood, etc., but in particular, the cracking coating according to the present invention has an extremely beautiful finish. Therefore, cosmetic tools, cosmetic containers, etc. are suitable objects to be coated.

[Painting line of the present invention]

An example of the painting line of the present invention is shown in FIG.

The product is attached in the device 21 by attaching the object to be coated on a conveyor belt that moves at a speed of 7 to 10 m/min.

Deliver to painting booth 22. In the front part 23 of the painting booth, spray painting is performed with a light-curing paint, and in the rear part 24, spray painting is performed with a cracking paint, and then the booth is moved to the setting zone 25,
Approximately 40 to 60℃ due to the far infrared lamp installed here
Heat for 5 to 10 minutes. A crack pattern is formed here.

Next, it passes through an irradiation zone 26 equipped with four high-pressure mercury lamps of 80 W/(!l) to complete curing of the photocurable paint, and is cooled to room temperature in a cooling zone 27.

[Effects of the present invention]

In the present invention, by selecting a photocurable paint as the undercoat as described above, there is no problem in cracking the topcoat at all, so the cracking of the topcoat is as if the film were to crack on water. Forms a wonderful pattern with no wrinkles. Furthermore, there is no need for a soft undercoat paint, and for example, methyl methacrylate or paints containing methyl methacrylate as a main component can be used, so the cured film is very hard, and cracks can form on the undercoat. Since this coating film is durable even if it comes to the surface, there is an advantage that it is not necessary to perform an additional top coat as in the past.

Since a photocurable paint that forms a hard film is used as the undercoat, the overall strength of the film is increased, and production efficiency is also improved.

Example A cosmetic tool (compact) made of ABS resin vacuum-deposited with aluminum was coated with an ultraviolet cross-linking curable paint known as Diabeam manufactured by Mitsubishi Rayon Co., Ltd. (composed of benzophenone, ultraviolet absorber, thinner, leveling agent, etc.) was spray-painted, and cracking paint was immediately applied while still wet.

The cracking paint is manufactured by Musashi Paint Co., Ltd. and is known by the part name Nitron. For 100 parts of this paint, add 80 to 100 parts of thinner to dilute it to a viscosity of 14 to 20.
(IHS, NK-2/20°C) was used.

After spraying the cracking paint, it is heated at about 60°C for about 5 minutes to evaporate the solvent in the UV cross-linking curable paint and forming cracks, and finally, it is irradiated with a high-pressure mercury lamp to form the UV cross-linking curable paint. The paint was completely cured. This resulted in a clean compact with no wrinkles and a cracked pattern.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a coated product according to the present invention, and FIGS. 2 and 3 are cross-sectional views of a coated product according to a conventional method. 1... Object to be coated 2... Coating film of light curing paint as undercoat 3... Coating film of cracking paint as top coat 4... Crack groove 11... Object to be coated using conventional method 12. ... Conventional method undercoat paint film 13 ... Top coat cracking paint film 14 ...
Crack groove 15...Wrinkles formed in the crack groove 16...Clear overcoat layer 21...Product installation equipment 22...Painting booth 2
3...Setting area sprayed with undercoat 24...Setting area sprayed with topcoat 25...Setting zone

Claims (1)

[Scope of Claims] 1. The object to be coated is coated with an undercoat of a light-curable paint that does not harden by heating, and while this is still uncured, a heat-fast-drying cracking paint is applied, and this is heated to cause the cracking. A cracking coating method characterized by forming cracks in a paint film and then irradiating light energy to harden the photocurable paint film. 2. Apply an undercoat to the object to be coated with a light-curable paint that does not harden by heating, and when this is still uncured, apply a heat-fast-drying cracking paint, and heat it to cause cracks in the cracking paint film. 1. A cracking coating method characterized by forming a photocurable paint, then coating a photocurable paint thereon, and then irradiating light energy to harden the photocurable paint film. 3. Apply an undercoat to the object to be coated with a light-curing paint that does not harden by heating, and when this is still uncured, apply a heat-fast-drying cracking paint, and heat it to cause cracks in the cracking paint film. This is then irradiated with light energy to cure the undercoat film, then a photo-curable paint is further applied on top of this, and light energy is irradiated onto this to cure the photo-curable paint film. A cracking coating method characterized by: