| 摘要 |
849,774. Moulding polyurethane foams. DUNLOP RUBBER CO. Ltd. Dec. 10, 1957 [Dec. 22, 1966], No. 39145/56. Class 87(2). [Also in Groups VIII, XIV and XXI] A rounded edge face 17 is formed on a slab 11 of trimmed, resilient polyurethane foam by subjecting the material to heat and pressure along a line adjacent to the edge, the pressure being directed substantially normally to a main face 18 or 19 of the slab. As shown, the edges are compressed at 15 by a die 14, attached to an upper electrode 13, against a lower electrode 12. Dielectric heat is applied and after release of pressure and removal of waste material the slab is left with rounded edge faces. Two or more layers of foam may be seamed together by the die (see Group VIII). |
