Coloured rubber or rubber-like plastic tubes - surrounded by flexible film sheathed in lead during vulcanisation

摘要

Tubes of rubber or rubber-like plastic, partic. coloured tubes or tubes with a coloured outer layer, are mfd. by applying a Pb sheath to the tube blank prior to vulcanisation, and removing it from the finished tube after vulanisation. This is performed by winding a flexible film around the blank, then enveloping it in Pb and vulcanising it, and then removing the film with the Pb sheath. the film is pref. applied in the form of a strip with a width corresponding to the o.d. of the blank or slightly larger for overlapping, perpendicularly to the longitudinal axis of the tube. It is made of plastic, e.g., polyamide, polyester or cellophane, or metal, e.g., Al. This method prevents the tube wall and pB sheath from affecting each other during vulcanisation.