| 摘要 |
<p>An insulating foam is prepd. by incorporating in a phenolic resin with a foaming agent comprising plaster. Pref. the plaster is reacted with an acid which is also used as hardener for the foam. The faom is pref. prepd. by placing a mixt. of phenolic resin and plaster opt. with other additives in a mould and adding the acid(s) e.g. oxalic, sulphuric or phosphoric acid which reacts with the plaster and thus causes foaming. Pref. the plaster is used as vehicle for incorporating a waterproofing agent and a plasticiser into the foam. The use of costly blowing agents is used (e.g. CFCl3 and pentane). The mechanical props. of the foam is also improved. The plaster also allows dispersion of other additives in the resin, e.g. water proofing agents and plasticisers.</p> |
