| 摘要 |
By starting with a silicone impression of the desired graining (natural leather) positively grained plates 4, 5, 6, 7 are produced in thermoplastic material (PVC) and are assembled by welding and then formed into a sleeve, the welding joints 8 then being postgrained by means of a graining roller 12, with a circumference greater than the length of the joints, obtained by casting and curing a heat-curable resin in an appropriate cylindrical die whose inner side wall is lined beforehand with an added strip of thermoplastic material grained by starting with the silicone impression. The sleeve of thermoplastic material is then coated with a layer of silicone which, after curing and folding back gives a graining sleeve made of negatively grained silicone which can be used for graining thermoplastic films. As a variant, the graining sleeve may be made of metal and may be obtained by an electrolytic metallising stage. <IMAGE> |
