| 摘要 |
811,398. Moulding plugs. EVERETT & CO. Ltd., S. & R. J. Nov. 12, 1957 [Nov. 21, 1956 ; Feb. 26, 1957], Nos. 35630/56 and 6454/57. Class 87(2). [Also in Groups VI and XVII] Stoppers for hypodermic syringes comprising a resilient body enclosed within a cup of halogenated ethylene, (see Group VI) are moulded in a stainless steel or aluminium mould 20. To form the cup, the interior 21 of the mould is lined with polytetrafLuorethylene which is applied in sheet form or by alternately dipping in or spraying with a dispersion and sintering to form layers. The mould 20 is then filled with rubber which is subsequently vulcanised or caused to set. When an aluminium mould is used, the mould is dissolved away by hydrochloric acid or sodium hydroxide. The inner surface of the polytetrafluorethylene cup may be roughened before the resilient material is added by the application of particles of polytetrafluorethylene metal or ceramic. |
