| 摘要 |
1,214,103. Extruding thermoplastics sheets. PLASTILUOR S.A. 27 March, 1969 [3 April, 1968], No. 16005/69. Heading B5A. [Also in Division F2] The surface A of an extruded thermoplastics sheet F, e.g. a sheet of polymethyl methacrylate, polystyrene or vinyl chloride, is rendered matt by application whilst malleable against the roughened surface of a lining 4b of roller 4, the material of the lining being of low thermal conductivity and sufficiently soft not to produce facets of high surface brilliance. The lining is preferably of a silicone elastomer, but may be of a suitable synthetic rubber such as neoprene, or P.T.F.E. with or without the addition of silicone compounds, or a resin bonded paper laminate. The lining may be protected by an addition of silicones to its outer surface. The temperature of roller 4 is maintained close to that of the sheet F by fluid flow in channels (8), Fig. 2 (not shown), and/or internal electrical heaters, or by heating the surface of the lining, e.g. with infrared lamps. In a second embodiment, Fig. 3 (not shown), lined roller (10) is situated between smooth or patterned steel rollers (12, 13) which are preferably heated to a temperature slightly below that of roller (10). In modifications, a second lined roller may be used, e.g. roller (13), to give sheet F a matt surface on both sides and a pair of rollers may be situated upstream or downstream of the lined roller to size the sheet. |
