| 摘要 |
A printable, paperlike structure is made from a sheet of flexifilaments of high-density crystalline polyethylene by permeating it with saturated steam while it is disposed between two generally parallel forming surfaces. At least one of these surfaces is porous and flexible, and they are pressed together sufficiently to restrain lateral shrinkage of the sheet and to prevent reduction of the birefringence of the film fibrils of the flexifilaments by more than 50%. The temperature of the saturated steam on the two sides of the sheet must differ by less than 5 DEG C. and be less than the melting point of the polyethylene but within 20 DEG C. thereof. Frictional contact of the forming surfaces with the sheet is maintained while cooling the sheet to below the temperature of the steam. The sheet may be made by the method of Specification 970,070. |
