| 摘要 |
1436436 Laminates DUNLOP Ltd 14 Oct 1974 [3 Nov 1973] 51144/73 Heading B5N [Also in Division A6] A laminate is formed of a wood layer sandwiched between two resin-impregnated fibre layers. Preferably, the resin impregnated fibre layer, which is of thickness 0À004 to 0À015 inch, contains by weight 40-60% fibres, and the wood layer which is of thickness 0À125 to 0À25 inch is formed of a low density (#0À45.10<SP>3</SP> kgm.<SP>-3</SP>) wood; e.g. obeche, balsa. In one embodiment, the resin-impregnated fibre layer is formed by the impregnation of a woven fibre sheet with a thermosetting resin, e.g. epoxy, phenolic, polyester or urea-formaldehyde. The fibres themselves are preferably of a low density (#1À6.10<SP>3</SP> kgm.<SP>-3</SP>) high elastic modulus (Young's Modulus #50 GNm.<SP>-2</SP>) type; e.g. aromatic polyamide. The resin impregnated fibre layers may be formed separately and cured before bonding to the wood with a suitable adhesive (e.g. epoxy resin) or may be formed by initially impregnating with resin and then curing and bonding to the wood in a single operation (the resin itself acting as a bonding agent). In the latter case the curing temperature should not exceed 100‹ C. to avoid wood damage; the range 80-100‹ C. being preferable. |
