| 摘要 |
Printing rollers are made from plasticized polyvinyl chloride or butyral by first moulding undersize, e.g. on a core, at 150 DEG C., then inserting in a slightly larger mould, filling the annular space with the composition and gelling at 150 DEG C., whereby a readily removable skin is formed. Suitable plasticizers are tricresyl phosphate, dibutyl, dioctyl, dihexyl and dicapryl phthalates. Fillers, e.g. anhydrite, barytes, china clay and ground silica, and stabilizers, e.g. lead salts, and extenders, e.g. vegetable oils, may be present.ALSO:Printing-rollers having a readily removable skin are made from plasticized polyvinyl resins, e.g. polyvinyl chloride or butyral, by first moulding an undersize roller, e.g. on a core, at 150 DEG C., for 20 minutes, then inserting it in a slightly larger mould, filling the annular space with the composition and again heating at 150 DEG C. for 20 minutes to gel. The moulds may be of steel which may be plated with chromium or nickel and may be lubricated with soft soap or plasticizer. |
