| 摘要 |
1,197,903. Moulding concrete elements; laminates. J. W. PEDLOW. 5 April, 1967 [12 April, 1966], No. 15545/67. Headings B5A and B5N. [Also in Divisions B1, B2, C7, E1 and F2] Concrete building elements are cast in a mould lined with a layer of P.V.C. bonded to a backing layer of foamed polyurethane internally coated with P.V.C. The foamed layer is penetrated partially or wholly by the wet concrete during casting and anchors the P.V.C. layer firmly to the cast element. The P.V.C. layer may be covered by a layer of release coated paper, which layer forms a medium through which the P.V.C. - foam laminate may be attached to the mould wall. The paper layer is retained by the mould upon removal of the cast element. The P.V.C.-foam laminate may be completely pre-formed prior to application to the mould or the mould may be dipped in a P.V.C. bath and a preformed foam layer stuck to the P.V.C. layer thus formed. Plaster of Paris, resinous, waxy or bituminous materials may also be cast on to the laminate. The P.V.C.-foam laminate is made by casting a layer of P.V.C. plastisol upon a release belt, partially gelling the layer, cooling the gelled layer, applying a preformed internally coated foamed layer by passage between nip rollers, and finally heating the laminate thus formed to fully cure the P.V.C. and to effect the bond between the layers. Bonding may be enhanced by gelling in such a manner as to leave a thin ungelled coating upon the partially gelled layer. Alternatively a separate ungelled coating may be applied. A second P.V.C. layer may be applied to the foam to form a sandwich structure. |
