| 摘要 |
Extruder die design for extrusion of cellular polymers, esp.. polyolefins. The die features extruded lips (3, 4) which are thin enough to easily be drastically chilled, pref. by a jet of cold air. The rest of the die is insulated (5, 6) from the chilling medium, e.g. by collars and pads of phenolic resin impregnated fibres. Esp. for extrusion of expanded polyethylene. Allows the melt to be chilled sufficiently to develop adequate melt strength for production of good foam without lowering the temp. of the bulk of the material passing through the die chamber sufficiently to cause set-up or erratic extrusion. |
