Multi-layer products

Abstract

Fibrous products, including single fibers, yarn and fibrous webs, of improved fineness are produced from extruded sheet material extruding in the form of a sheet-like, multi-layer composite stream a plurality of extrudable materials, at least one of which is a synthetic thermoplastic fiber-forming polymer and another of which is expandable or swellable in nature, which layers extend generally parallel to the faces of the stream, with each such layer containing either a fiber-forming polymer or an expandable or swellable extrudable material with the different layers being interspersed in the composite stream; solidifying this composite stream into a multi-layer sheet, not earlier than during such solidification subjecting the multi-layer sheet to a swelling or expanding treatment to aid in its mechanical disruption, and then mechanically disrupting the swollen or expanded sheet to produce a fibrous product of increased fineness. Alternatively, the other extrudable material can be incompatible with the polymer so as to separate therefrom during mechanical disruption. Instead of solidifying the extruded stream while intact, the stream can be divided during extrusion along spaced generally parallel planes extending through the stream at an angle to its faces and solidified in this divided state to form separate strips each containing a section of the multi-layer composite stream. These separate strips are then treated as indicated to at least partially remove the removable material and at least partially separate the polymeric layers therein. Alternatively, the stream can be divided and re-united before solidification.

Dependencies are inferred from the claim text.