| 摘要 |
Coherent expanded nonwoven sheets having a density of less than 0.16 g/mL are comprised of fibrids of a wholly synthetic polymer, preferably not melting below 130 DEG C, and optionally containing up to 80% by weight floc. The sheet is comprised of a plurality of paper-like membranous layers which join and separate at random throughout the thickness of the sheet to form expanded cells. The expanded nonwoven sheets are prepared by rapid vaporization of water in a wet, never-dried sheet of fibrids containing at least 60% by weight water. Rapid vaporization of the water preferably is induced by dielectric heating. Embossing may be used before or during expansion to produce a sheet which is expanded only in selected areas. |
