CENTRIFUGALLY SPINNING POLYOLEFIN SOLUTION THROUGH PERFORATED DRUM AND BASKET

摘要

1373708 Paper made from polyolefin fibrils GULF RESEARCH & DEVELOPMENT CO 22 Nov 1972 [26 Nov 1971] 54061/72 Heading D2B [Also in Division B5] Fibrils are produced by centrifugal spinning of a hot solution of a polyolefin. The solution is supplied from line 20 to pipes 96 inside the rotatable drum 88, preferably of inverted conical shape. The solution is spun out at at least 25g's from holes 87 on to basket 78 which is cooled for example by sprays 114 to a temperature such that the polyolefin precipitates as a swollen fibrous mass. Basket 78 may be rotated to aid in removing some of the solvent. The fibrous mass is collected in tray 100 and the liquid in 102 from which it may be recovered and re-used. The fibrous mass is then pressed to remove a large proportion of remaining solvent, cut into lengths and then beaten in a liquid that is miscible with the solvent but a non-solvent for the polyolefin. The resulting fibrils are then recovered by filtration. The preferred solvents are high-boiling hydrocarbons such as decalin or aliphatic hydrocarbon and the preferred non-solvent is isopropanol. The liquid used to cool the basket may be the same as the solvent, which part assists in material recovery. The fibrils are recoverable as a pulp which preferably contains a small residue of solvent. This pulp may be laid from its suspension in isopropanol to give a polyolefin paper.