| 摘要 |
A method of making dual or multi-porosity porous plastic strips comprising placing a first quantity of plastic granules into a mold, and placing a second or additional quantities of plastic granules into the mold above the first quantity. The particle sizes of each of the quantities of granules placed into the mold are different from the particle sizes of all the other quantities of granules in the mold. The granules are subjected to heat and pressure so as to fuse them together into a self-sustaining porous plastic billet. The billet has a number of fused-together regions corresponding to the number of quantities of granules placed into the mold. The billet is sliced in a direction transverse to the planes containing the interfaces between the regions of the billet so as to create strips, each strip comprising interconnected regions have porosities which differ from one another. The mold may be cylindrical and the strip created by skiving it off the cylindrical surface of the billet. A fusible barrier sheet or sheets may be placed into the mold between the quantities of granules so that the final strips contain micro-porous or non-porous barrier layers between the porous plastic regions. Where a barrier layer is used, the two porous plastic regions could be of the same porosity.
|
