| 摘要 |
A rawling comprising a porous core (11), a shell enclosing the core which including a layer(s) (13, 14 and 16) impregnated with an uncured thermosetting plastic, is first made. The rawling(s) (23) is then positioned in a mould and cured. The shell of the rawling preferably comprises an air-tight skin (12), a layer of peripherally extending fibres (13), a third layer of axially extending fibres (14) and then a fourth layer of peripherally extending fibres (16). In a particular embodiment, two rawlings are compressed together to form the finished product. The core may be a hand foamed plastic eg polyurethane. <IMAGE> |
