| 摘要 |
<p>A reinforced sheet of polyurethane foam is made by forcing under pressure a liquid foaming mixture, e.g. of a polyisocyanate (particularly toluene diisocyanate), and a hydroxyl-containing compound, (e.g. glycols, polyols, polyesters or polyethers), on to and through a discontinuous reinforcing layer so that the reinforcing layer is completely surrounded by the foam-forming material which, after subsequent foaming, e.g. by heat, forms a relatively thin sheet in which the reinforcing elements are dispersed substantially parallel to the broad faces thereof. Specified reinforcing materials are an open mesh screen of "Saran" (Registered Trade Mark), fibre glass, nylon, metal wire, cotton and jute, a plurality of parallel wires, a mat of randomly looped strands or an electrically conducting wire laid in continuous loops, the ends of which are brought outside of the sheet; this last being an electrical heating element which may also comprise additional non-metallic reinforcing layers of the materials previously mentioned.</p> |
