| 摘要 |
1. Method and apparatus for manufacturing plastic profiles with a fluorinated layer. 2.1 In order to obtain low permeation rates for liquids and gases, pipe fittings (polyethylene) are treated on their inside and/or outside with fluorine gas dissolved in liquid. It is disadvantageous that only relatively short pipe fittings can be fluorinated, low reaction temperatures requiring long treatment times. The object is to use a fluorination method which can be carried out continuously with variable reaction times. 2.2 This object is achieved by a method in which, during the continuous extrusion of plastic pipes, the inside and/or outside surface is treated with a gas containing fluorine directly after leaving the extruder head or following extrusion. The reaction time of the reaction gas is varied according to the rate of extrusion. 2.3 The pipe surfaces are chemically altered for the purpose of reducing the permeation of liquids and gases. <IMAGE> |
