JPS5831237B2 - How to apply water-based paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of applying a water-based paint, and particularly to a method of painting that can significantly improve the adhesive force between a substrate surface and a paint film.

Traditionally used oil-based paints have the problem of evaporation of solvent during painting, polluting the air and harming the health of painting workers.In recent years, however, the use of water-based paints, which do not have these problems, has rapidly increased. ing.

However, water-based paints can be used for concrete, mortar, etc.
When painted on various base materials such as LC board, calcium silicate board, plaster, asbestos slate board, plasterboard, wood, etc.
The adhesion of the coating film to the substrate surface is lower than that of general oil-based paints, and especially when the substrate surface is aged or chalky, the adhesion strength is extremely low, and within a relatively short period of time after painting. The disadvantage is that the coating film peels off from the substrate surface.

Therefore, in order to improve the above-mentioned adhesive strength of water-based paints, water-based emulsions such as polyvinyl acetate and vinyl acetate-acrylic ester copolymers, butanol solutions of polyacrylic esters, methanol solutions of polyvinyl acetate, etc. A method has been proposed in which the surface of the substrate is pretreated with a surface conditioner and then a water-based paint is applied to this surface, but even with this method, sufficient improvement in the adhesive strength cannot be expected.

In particular, if the base material surface is aged or chalky, the effect of using the underground conditioner will be small and satisfactory results will not be obtained, so in this case, a high degree of cleaning of the base material surface is required. As a result, the number of man-hours required for painting increases significantly, resulting in a disadvantage that the painting cost increases.

The present invention aims to provide a water-based paint coating method that solves the above-mentioned disadvantages and disadvantages.This method involves treating the base material surface with an alkyd composition in advance, and then applying the water-based paint to this treated surface. It is characterized by
This method not only greatly improves the adhesion between the base material surface and the water-based paint film, but also makes it easier to apply the water-based paint, and the painted surface has excellent gloss and water resistance. It also has the effect of being highly waterproof.

The method of the present invention will be explained in detail below.

The alkyd composition used in the method of the present invention refers to those described in (a), (b), and (c) below.

(a) Alkyd resin obtained by reacting one or more of polyhydric alcohols, polybasic acids, and fatty acids (and/or oils and fats), or this alkyd resin with various natural or synthetic resins other than alkyd resins. Or polybasic in a glyceride mixture obtained by transesterifying one or more types of modified alkyd resin fats and oils modified using various vinyl monomers and one or more types of polyhydric alcohols. An alkyd resin obtained by reacting an acid, or a modified alkyd resin obtained by modifying this alkyd resin using various natural or synthetic resins other than alkyd resins or various vinyl nitrates, (c) above (a) and/or Organic solvent solution of (0) In the above, polyhydric alcohols include ethylene glycol, propylene glycol, glycerin 9-methylolpropane, pentaerysditol, triglycerol,
Epoxy resins, etc. Polybasic acids include phthalic anhydride, isophthalic acid, terephthalic acid, maleic anhydride, fumaric acid, adipic acid, itaconic acid, rosin maleic anhydride, terpene maleic anhydride, maleated oil, anhydrous Examples include tetrachlorophthalic acid and the like.

Furthermore, the oils and fats mentioned above include linseed oil, soybean oil, cottonseed oil, tung oil, castor oil, coconut oil, fish oil, and safflower oil, and the fatty acids include palmitic acid, lylunic acid, oleic acid, ricinoleic acid, and linoleic acid. Examples include acids.

When pre-treating the surface of a substrate using such an alkyd composition, if necessary, aromatic hydrocarbons such as xylene and toluene, kerosene (
There is no problem in blending solvents such as petroleum solvents such as kerosene) and gasoline (volatile oil), and additives such as surfactants and curing catalysts may also be blended.

The substrate surface may be treated with the above alkyd composition by any suitable method such as ordinary brush coating, roll coating, or spray coating. It is sufficient that the film is formed thinly, and increasing the amount of treatment more than necessary not only does not improve the effect any further but is disadvantageous in terms of economic efficiency because it increases costs.

The reason why pre-treatment of the substrate surface in this way brings about the above-mentioned remarkable effects is not necessarily clear, but it is likely that the alkyd composition used in this treatment is It has excellent compatibility with paints and exhibits strong adhesion to the substrate surface, so as a result, excellent coatings can be achieved through the synergistic effect of such alkyd compositions and water-based paints. It is thought that this is because of this.

Next, the water-based paint used in the method of the present invention is as follows:
A single polymer obtained by polymerizing one or more monomers such as vinyl acetate, acrylic acid, acrylic ester, styrene, butadiene, vinyl chloride, vinyl9dene chloride, vinyl fluoride, vinylidene fluoride, etc. Aqueous emulsions of polymers or copolymers, aqueous resin solutions containing one or more of water-soluble acrylic resins, water-soluble melamine resins, water-soluble phenol resins, etc., and pigments, dispersants, thickeners, Examples include those containing components such as antifungal agents, and inorganic or organic spray paints commonly referred to as ricin.

In the method of the present invention, the above-mentioned water-based paint is applied after treating the substrate surface with the above-mentioned alkyd composition. At this time, the treated surface is wetted with the alkyd composition or the treated surface is It may be dried by natural drying or the like.

The method of applying the water-based paint, the amount of application, etc. may be carried out in accordance with those conventionally practiced in the art, and there are no particular restrictions in these respects.

The water-based paint may be a mixture of the water-based paint and the alkyd composition.

According to the method of the present invention, even when the substrate surface is new, even when it is aged or chalky,
It is now possible to paint with significantly improved adhesion between the paint film and the substrate surface without the need for sophisticated cleaning as in the past, and a significant streamlining of the painting process is achieved.

Next, examples of the method of the present invention will be given.

In the following description, all parts simply refer to parts by weight.

Example 1 A mixture of 136 parts of pentaerythritol, 200 parts of soybean oil fatty acid, 100 parts of linseed oil fatty acid, and 148 parts of phthalic anhydride was heated to a temperature of 200°C in a nitrogen stream and reacted for 5 hours, resulting in a number average molecular weight of about 7× 105 alkyd resin was obtained,
This was diluted with 800 parts of kerosene to obtain an alkyd composition.

Next, the surface of the ALC board is coated with the above alkyd composition, and after 24 hours, an acrylic water-based paint, Marina (trade name, manufactured by Atom Paint Co., Ltd.), is brushed onto the treated surface, and it is thoroughly dried. The painting was completed.

By pasting cellophane tape (product name manufactured by Chiban Co., Ltd.) on this painted surface and peeling it off at once, the paint film and AL
The adhesive strength with the C plate was examined and the results were as shown in Table 1.

For comparison, the same table shows that the surface of the ALC board was coated with a commercially available vinyl acetate resin aqueous emulsion or a butanol solution of polyacrylic acid ester instead of being coated with an alkyd composition. Marina was applied to these treated surfaces in the same manner as above, and the adhesive strength was examined in the same manner. The results are also shown.

[Judgment criteria for adhesive strength]

A: Unable to peel off the coating B: Slight peeling of the coating C: Peeling of the coating Example 2 A mixture of 70 parts of pentaerythritol, 70 parts of trimethylolpropane, and 300 parts of linseed oil fatty acid was heated at 250°C (
(in a nitrogen stream) for 4 hours, and then phthalic anhydride 1
A mixture of 0.00 parts and 55 parts of isophthalic acid was added, heated to a temperature of 230°C, and reacted at this temperature for 4 hours to obtain an alkyd resin.To this, 550 parts of mineral spirit and a nonionic surfactant (HLB = 13.5) were added. The two parts were mixed to form an alkyd composition.

Next, the mortar surface is coated with the above alkyd composition, and before the coated surface dries, 30 parts of cement-based lysine, 24 parts of water, and 5 parts of the above alkyd composition are mixed. Painted by spraying with water-based paint.

The paint film formed in this way adheres extremely firmly to the mortar surface, and has approximately twice the adhesive strength (measured with an Autograph manufactured by Shimadzu Corporation) compared to when a conventional base conditioner is used. )showed that.

Claims (1)

[Claims] 1. A method for painting a water-based paint, which comprises treating the surface of a base material in advance with an alkyd composition, and then applying a water-based paint to this treated surface.