| 摘要 |
PURPOSE:To obtain a powder coating having greatly improved pigment dispersibility and excellent hiding power and smoothness, by dispersing uniformly a pigment in a soln. of a resin in a solvent by a wet dispersion mixer and flash-drying the dispersion in a vacuum. CONSTITUTION:A powder coating is obtd. through (1) wet dispersion step of dispersing a solvent, a pigment, a resin for dispersing the pigment and/or a powder coating resin by a wet dispersion mixer to obtain a uniform liquid dispersion and (2) a vacuum drying step of drying said dispersion in a vacuum with a vacuum dryer comprising a heating tube 1, a vacuum powder collecting chamber 2, an evacuating device 5 and a solvent recovery device (composed of a condenser 3 and a solvent reservoir 4) to obtain a powder coating. It is preferred that the vacuum powder collecting chamber is kept under a pressure of about 4-6cmHg and at a temp. substantially higher than the b.p. of the solvent under that pressure.
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