Nippon Paint Compnay, Ltd.

Kazuo Uenoyama

Tetsuro Kajino

Takayuki Shibata

Teruaki Kuwajima

Toshihiro Okai

Hidefumi Okuda

Hiroshi Mashima

Nobuhiro Sudo

Toshiya Koike

Takao Kageyama

Masahiro Nagasaki

Masaki Takae

Method for suppressing foams in booth circulating water

The object of the present invention is reuse of the filtrate of a paint mist-cleaning water mixture as cleaning water without reduction in concentration efficiency. According to the present invention, a waste paint-cleaning water mixture 2 available on trapping a water-based paint mist in cleaning water 1 is concentrated to recover the paint and the aqueous phase is recycled as cleaning water. In this system, the cleaning water prepared by reusing the aqueous phase is adjusted to an acid value of not greater than 10 and a pH value of 7.0 to 9.0. Controlling the amount of low molecular acid components in the aqueous phase in this manner prevents an abnormal viscosity increase in the filtration-concentration of the waste paint-cleaning water mixture.

Method for recycling a paint recovery effluent

A water-based paint composition suitable for re-use with the retention of the intended coating property when recovered from a flushing water utilized to collect the paint composition remain undeposited on an article in a painting process. The water-based paint composition comprises a water-soluble resin selected from the group consisting of alkyd resin and acrylic resin to have an acid value of 25 to 100, a hydroxyl value of 35 to 200, and a solubility parameter (SP) of 10.0 to 11.0. The paint composition also incorporate a curing agent having a solubility parameter (SP) which is higher than that of the water-soluble resin by 0.5 to 3.0.

Water-based paint composition

The present invention provides a metallic paint film featuring a remarkably excellent coating appearance as well as weather resistance, by using a specific combination of a water borne paint and thermosetting clear paint in compliance with the wet-on-wet two-coat, one-bake painting method.

Method of painting

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Osaka, Japan

Kazuo Uenoyama