| 摘要 |
<p>1,205,877. Sheet casting. IMPERIAL CHEMICAL INDUSTRIES Ltd. 25 June, 1969 [11 July, 1968], No. 33110/68. Divided out of 1,014,022. Heading B5A. A casting band for use in the formation of plastics sheet material is made by casting a layer of an organopolysiloxane gum composition on a master pattern, allowing the composition to cure to an elastomeric sheet, removing the cured sheet from the pattern and abrading that surface of the cured sheet which was in contact with the pattern. With such a casting band, slippage of the cast plastics sheet and the band during operations performed on the plastics sheet whilst it is still on the band is prevented without diminishing the ease with which the cast sheet may be finally peeled from the band. The abrading may be applied only to certain discrete areas of the band and may be effected by chemical means or mechanical means such as moving the band under tension over an abrasive surface, for example, a fabric mounted upon a support, treating the band with an abrasive powder, sand blasting the band or applying rotating brushes to it.</p> |
