JPH07166101A - Aqueous emulsion-based coating - Google Patents

Abstract

PURPOSE:To obtain an emulsion-based coating excellent in vibration-damping performance and useful as an undercoating for automobiles by using a resin consisting mainly of a styrene-modified acrylic resin as a polymer. CONSTITUTION:This coating is obtained by using a resin consisting essentially of a styrene-based acrylic resin as a polymer providing a coating component in dispersing the polymer in water. Furthermore, the resin is preferably dispersed in water to have so high solid content as >=50wt.% based on the coating and it may preferably further be blended with a filler, a defoamant, a thickener, a dispersant, a wetting agent, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous emulsion paint suitable as an undercoat paint for automobiles.

[0002]

2. Description of the Related Art Conventionally, polyvinyl chloride plastisols have been widely used as coating materials for undercoats of automobiles. Films are often removed by incineration. In addition, by applying the polyvinyl chloride undercoat material thickly to a place where a stone buzzing noise is generated in a tire house or the like to exert a vibration damping effect, noise due to the stone bounce can be heard in the vehicle interior. It's suppressed.

However, the above-mentioned polyvinyl chloride is environmentally problematic because it generates hydrogen chloride when incinerated. For this reason, paints replacing polyvinyl chloride plastisols have been demanded, and water-based emulsion paints using water as a dispersion medium have been attracting attention as paints in line with this.

In this case, it is desired that the coating material for automobiles has good vibration damping performance, and it is necessary to develop an aqueous emulsion coating material which gives high damping performance.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an aqueous emulsion paint capable of forming a coating film having high vibration damping performance.

[0006]

Means and Actions for Solving the Problems As a result of intensive studies for solving the above-mentioned object, the present inventor has found that in an aqueous emulsion coating composition in which a polymer as a coating film component is dispersed in water, The inventors have found that a coating film having excellent vibration damping properties can be formed by using a styrene-modified acrylic resin as a main component, and have completed the present invention.

Therefore, the present invention relates to an aqueous emulsion coating composition comprising a polymer as a coating film component dispersed in water, wherein the polymer comprises a styrene-modified acrylic resin as a main component. provide.

The present invention will be described in more detail below. The aqueous emulsion coating composition of the present invention comprises a styrene-modified acrylic resin as a main component as a polymer. In this case, as the styrene-modified acrylic resin, VOCOAT-5410 (solid content: 15) manufactured by Dainippon Ink and Chemicals, Inc.
%) Can be used. Further, the styrene-modified acrylic resin is preferably dispersed in water with a solid content as high as possible in order to reduce the amount of water to be evaporated, and specifically, it is preferably 50% by weight or more in the coating material.

In addition to the above components, the water-based emulsion paint of the present invention may contain a filler, a defoaming agent, a thickener, a dispersant, a wetting agent, etc., if necessary.

In the case of baking and drying, as the filler, it is preferable to add a filler having no biaxially oriented shape for the purpose of facilitating the volatilization of water and preventing the occurrence of blistering. Can include calcium carbonate, diatomaceous earth, and the like, and a part of these fillers may be used in place of hollow fine particles made of glass or resin.
The particle size of the filler is preferably within a maximum of 10 μm in consideration of spraying workability.

The amount of the filler compounded is 100% resin solids.
The range of 50 to 300 parts, especially 150 to 250 parts is preferable with respect to the parts. If the blending amount is less than 50 parts, appropriate thixotropy may not be obtained even in combination with a thickener, and swelling may occur easily. On the other hand, 30
If it exceeds 0 part, it becomes difficult for the resin to sufficiently wet the filler, and the performance may be deteriorated to make the coating film performance unsatisfactory, and cracks may easily occur.

The defoaming agent is blended for the purpose of reducing the occurrence of bubbles and facilitating the elimination of bubbles once formed, since low viscosity emulsions and emulsion mixtures are apt to generate bubbles by stirring.

The thickener is for helping the dispersion of the filler to prevent settling, improving the stability of the coating material, finishing the viscosity adjustment to an appropriate level, and obtaining a balance of both sprayability and thixotropy. For example, methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, protein, polyvinyl alcohol, sodium acrylate, etc. can be used alone or in combination of two or more at a usual dose.

The dispersant is for helping the filler to be dispersed in water, and various sodium polyphosphates, surfactants and the like can be exemplified, and they can be used in a usual dose.

The aqueous emulsion paint of the present invention can be prepared by mixing the above components. For example, resin components (latex), fillers, dispersants, wetting agents, etc. are kneaded, then a thickener is added to disperse them, and then a defoaming agent is added to defoam and finally filtered. The aqueous emulsion coating composition of the present invention can be prepared. As the disperser, a high speed disperser is suitable, and since the kneading and the viscosity adjustment afterward can be performed at the same time, the production efficiency can be made higher than that of other machines.

The aqueous emulsion paint of the present invention can be used as an undercoat paint for parts such as automobile tire houses, under floors and front aprons, and also as a sealing material for seams of seals.

In this case, a general high-pressure pump can be used for coating by a spray gun coating method or the like, and the coating amount is 150 to 40 in terms of the thickness of the dried coating material.
It can be about 100 μm.

The drying condition is, for example, 10 to 6 at room temperature.
After leaving it for 0 minutes, it is dried in a calcining furnace at about 110 ° C. for about 8 to 12 minutes, then at 120 to 150 ° C. for 20 to 30 minutes in an intermediate coating furnace, and finally in a top coating furnace at 120 to 150 ° C. for 2 minutes.
Conditions for drying for 0 to 30 minutes can be adopted.

[0019]

EFFECT OF THE INVENTION The aqueous emulsion coating composition of the present invention can provide a coating film having excellent vibration damping performance while maintaining the performance as an aqueous undercoat material.

[0020]

EXAMPLES The present invention will be specifically described below by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Examples 1 to 4 and Comparative Examples 1 to 6] The components shown in Table 1 were mixed in the compounding amounts shown in the same table, and the vibration damping performance was evaluated by measuring the loss coefficient by the following method. The results are also shown in Table 1. <Loss factor> Apply the sample to a 0.8 mm steel plate,
After baking for 20 minutes at 130 ℃, the coating thickness 2
mm. This sample was measured at a frequency of 200 Hz and a temperature of 20 ° C. by the one-end fixing method.

[0022]

[Table 1]

From the above results, the addition of the styrene-modified acrylic resin as the main component makes it possible to obtain a water-based vibration-damping performance superior to other water-based emulsion paints such as polyurethane resin, acrylic resin and styrene-butadiene rubber. It was confirmed that an undercoat material was obtained.

Claims (1)

[Claims] 1. An aqueous emulsion paint comprising a polymer as a coating film component dispersed in water, wherein the polymer contains a styrene-modified acrylic resin as a main component.