| 摘要 |
A process is provided for the continuous production of nonwoven webs in cylindrical or sheet form from thermoplastic fibers, spinning the fibers continuously from a melt onto a rotating mandrel and winding them up on the mandrel to form a generally spirally wound cylinder. Density of the wound cylinder is controlled by controlling the distance between the rotating mandrel and the orifices of the spinning die through which the molten polymeric material is spun. If the spinning of the fibers is continuous, the cylinder can be formed in a continuous length. Control of the spinning rate in relation to the diameter and rate of rotation of the mandrel and the rate of advance of the cylinder on the mandrel controls the thickness of the cylinder. The cylinder can be drawn off the mandrel and used as a cylinder, or either slit lengthwise and opened out, or collapsed onto itself, for use as a sheet. The process is particularly adapted for forming filter elements. |
