| 摘要 |
<p>Roof tile is made as in CH 499703. For 100 pts/wt. of crushed fine gravel, 28 of an amalgam of equal pts of polyester, polyvinyl chloride, solid polystyrene and a liquid plastics, and 2 pts/wt. of stone dust are mixed. Pref. the mixture is cold-treated in a piston drum, with addition of hardener. The tiles are non-inflammable.</p> |
