JP5358879B2 - Manufacturing method of paint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for preparing a painted article having excellent evenness of paint coat achieved by preventing sagging and unevenness of coated paint. <P>SOLUTION: The method for preparing a painted article comprises a step of applying paint onto a surface of an article to be painted under such a condition that the surface temperature thereof is kept higher than the boiling temperature of the paint. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

The present invention relates to a method for producing a coated product that prevents sagging and uneven coating of a water-based paint containing a silver colloid .

The paints are classified into organic solvent paints and water paints according to the liquid medium used. Organic solvent-based paints are widely used as industrial paints because they are excellent in film quality such as adhesion to an object to be coated and film hardness, and also have good workability in the coating process.
In recent years, however, water-based paints use water as the main solvent, so they are less dangerous to workers in the paint environment than organic solvent-based paints. They also prevent global warming (reducing CO2 emissions) and air pollution. It is attracting attention because it contributes to global environmental problems such as prevention (reduction of volatile organic compound emissions).

Immediately after the paint is applied to the object to be coated, a phenomenon that the paint moves due to its own weight, so-called sagging of the paint, occurs, and the appearance of the finished paint may be deteriorated.
Further, the appearance of the finished coated product is also deteriorated due to uneven coating due to the wettability of the coating on the surface (hereinafter referred to as the coated surface) where the coating is applied to the object. In particular, water-based paints using water, which has a higher latent heat of vaporization (difficult to evaporate) as compared with organic solvent-based paints, are remarkable. In view of this, a coating method is disclosed in which sagging of the paint is prevented by adjusting the paint temperature (higher than the standard temperature) due to the evaporation promoting effect of the diluent solvent (Patent Document 1).
JP 2006-281165 A

  In Patent Document 1, the paint temperature is set higher than the standard paint temperature, and the evaporation of the diluting solvent is positively increased. However, when the evaporation of the diluting solvent is increased, the viscosity of the paint is increased in the coating apparatus, and in the worst case, the paint is solidified in the coating apparatus, which makes it impossible to apply the paint.

The present invention relates to a coated product to which a water-based paint containing silver colloid is applied, and at least the surface of the object to be coated is applied as a parent paint, and the surface to which the paint is applied is simultaneously heated to a temperature exceeding the boiling point of the paint. In this state, the gist is a method for producing a coated product to be spray-coated.

By making the coated surface a parent paint and setting the temperature above the boiling point of the paint, the surface free energy of the coated surface is increased, the interfacial tension with the paint is reduced, there is no uneven coating, and more paint is applied. The surface free energy change due to the coating can be suppressed by immediately solidifying the coating, and there can be obtained a coated product having no coating unevenness and excellent coating uniformity.
In addition, the use of water-based paints can reduce CO2 emissions (prevent global warming) and reduce volatile organic compound emissions (prevent air pollution). In water-based paints containing silver colloids , by eliminating the sagging or unevenness of the paint, there is a part where the glitter is reduced due to aggregation, separation, or movement of the silver colloid in the coated film. Can be prevented.

The present invention has realized the object of suppressing dripping of the paint by positively evaporating the liquid medium of the water-based paint containing the silver colloid coated on the object to be coated.

The material of the object to be coated is not particularly limited as long as it can be painted. Specifically, metal materials such as aluminum or its alloy, copper or its alloy, iron or its alloy, zinc or its alloy, magnesium or its alloy, titanium or its alloy, vinyl chloride, polystyrene, acrylic, polycarbonate, acrylonitrile butadiene Styrene copolymer, acrylonitrile styrene copolymer, polyethylene, polypropylene, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, polyamide, nylon, polyacetal and other thermoplastic resin materials, polystyrene, polyolefin, poly Thermoplastic elastomers such as vinyl chloride, polyurethane, polyester, and polyamide, silicone, styrene butadiene, urethane, butadiene Synthetic rubber and natural rubber such as isoprene and fluorine, thermosetting resin materials such as epoxy resin, phenol resin, cyanate resin, urea resin and guanamine resin, ceramic materials such as alumina, zirconia and ceramics, natural materials such as wood and paper, etc. Can be used.
These materials may be one kind or a mixture of two or more kinds. Furthermore, a base treatment layer may be formed on these materials by electroplating, electroless plating, painting, printing, or by precious metal plating such as nickel, chromium, or gold, painting, printing, or the like.

The paint is not particularly limited as long as it is a water-based paint using a solution of water or a mixture of water and an organic solvent and contains at least a silver colloid . For example, an enamel paint containing a dye, a pigment, or a metal powder as a color material may be used.

  As a method of making the surface on which the paint is applied a parent paint, and simultaneously setting the surface on which the paint is applied to a temperature exceeding the boiling point of the paint, a method of rolling the application surface with a flame such as a gas burner can be used.

  Specifically, flame treatment in which an oxidation flame, a silicic oxidation flame, a titanium oxidation flame, an aluminum oxidation flame, or the like is sprayed on the coated surface can be used.

Example 1
A white material made of a polycarbonate resin having an outer diameter of 10 mm and a length of 100 mm and having a circular outer cross-section is degreased with isopropyl alcohol, and then subjected to an oxidization flame treatment (manufactured by Tsubaki Machine Co., Ltd., BT -20VX) to make the paint to be applied later a parent paint, and at the same time, the temperature of the coated surface was set to 200 ° C. Next, water-based silver colloidal paint (the following composition, boiling point: 100 ° C.) is spray-coated while the temperature of the coated surface is 100 ° C., and then dried under the conditions of 80 ° C. and 24 hours, and the average film thickness is 5 μm. A painted product was obtained.
<Composition of water-based silver colloid paint>
AQ20 clear (acrylic resin paint: manufactured by Musashi Paint Co., Ltd.) 10.0% by weight
84.9% by weight of water
AG70nm (silver nanoparticles: ULVAC Material Co., Ltd.) 5.0% by weight
DISPERBYK-190 (dispersing agent: manufactured by Big Chemie Japan Co., Ltd.) 0.1% by weight
The above components were dispersed in a ball mill for 24 hours to obtain a water-based silver colloid paint.

(Comparative Example 1)
In Example 1, a coated material having an average film thickness of 5 μm was obtained in the same manner as in Example 1 except that the coated surface was not changed to a parent paint and the temperature of the coated surface was changed to room temperature.

<Evaluation of coating sagging and uneven coating>
Visually observed under illumination for color observation (natural daylight illumination) in accordance with JIS K 5600-4-3: 1999 “General test method for paints—Part 4: Visual characteristics of coating film—Section 3: Visual comparison of colors” The evaluation of the sagging of the paint and the unevenness of the coating were carried out.

<Evaluation of coating film uniformity>
Using an eddy current film thickness meter (manufactured by Sanko Electronic Laboratory Co., Ltd., EDY-1000), the coated surface was measured at 10 locations (10 mm intervals) in the longitudinal direction, and the difference between the minimum film thickness and the maximum film thickness The film uniformity was evaluated. In addition, the average value of the above ten measurement points was defined as “average film thickness”.

  As described above in detail, the method for producing a coated product of the present invention can prevent sagging of coating and uneven coating, and has excellent coating film uniformity.

Claims (2)

In a coated product coated with a water-based paint containing silver colloid , at least the surface to which the paint is applied is treated as a parent paint, and at the same time the surface to which the paint is applied is at a temperature exceeding the boiling point of the paint. , A method of manufacturing a painted product for spray coating. 2. The production of a coated article according to claim 1, wherein the surface of the object to be coated is subjected to a parent coating treatment, and the step of simultaneously setting the surface to which the coating is applied to a temperature exceeding the boiling point of the coating is performed by an oxidation flame treatment. Method.