| 摘要 |
1515968 High molecular weight film by extrusion IDEMITSU PETROCHEMICAL Co Ltd 4 Aug 1976 [7 Aug 1975] 32455/76 Heading B5A A tubular film of high molecular weight, high density polyethylene material, is produced by the internal air pressure inflation of a tube of the material extruded from the annular outlet of a die 1, the tube passing to the location of inflation around a mandrel having a reduced diameter portion adjacent the die, and having a bore 2 for the passage of the inflating air from the die, and contact between the tube and mandrel is prevented by a plurality of holes 4 at the smaller diameter end of the mandrel, through which air is drawn by the aspirating effect of the extruding tube to flow in the extrusion direction between the tube and the mandrel. The end of the mandrel adjacent the extrusion outlet is of a smaller external diameter than the inner diameter of the outlet, and the diameter of the remainder of the mandrel may be the same, or slightly less, or slightly greater than the inner diameter of the outlet. The tube is also externally cooled by an air ring 7. Results are given of comparative tests relating to thickness deviation, and tear and impact strength, of 10 micron film. |
