| 摘要 |
A polyolefine, e.g. polyethylene, is reduced in viscosity by feeding the polymer to at least one shearing zone at a controlled rate in which it is subjected to a shearing action, passing the polymer through an extrusion zone and maintaining a positive back pressure on the polymer within the extrusion and shearing zones to maintain the polymer in the shearing zone for a time sufficient to effect a viscosity reduction of the polymer in the shearing zone and regulating the back pressure so as to maintain a predetermined melt index of the thus extruded material. The shearing zone may comprise a first zone spaced from a second zone. An apparatus is described with drawings (not shown) (see Division B5). Specifications 790,195 and 853,414 are referred to. |
