| 摘要 |
<p>The present invention pertains to a powder coating material comprising particles having a particle size distribution which satisfies the following equation: [d(s,90)/d(s,10)]2/[d(s,90)-7]<=3.5 and in which d(s,90) is greater than 7 mum, d(s,90) and d(s,10) being measured in microns. The powder coatings can be obtained via a grinding-classification process or an agglomeration process. In a preferred embodiment the particles are prepared by a process which comprises mechanical fusion of a powder coating material, wherein the powder is brought to a maximum temperature in the range of from the Tg of the powder to 15° C. above the Tg, at a heating rate for at least the last 3° C., preferably at least the last 4° C., up to the maximum temperature of no more than 4° C. per minute, and after a period in the range of from 0 to 40 minutes at the maximum temperature the powder is cooled.</p> |
