The Dow Chemical Company

Gene P Young

Zdravko P Jezic

Gerald M Lancaster

Ricky L Tabor

Malcolm F Finlayson

John O Bieser

John O Biesser

A method is disclosed for making thermoplastic bicomponent fibers by contacting under thermally bonding conditions (a) a first component being at least one high performance thermoplastic polymer, such as PET, PBT, nylon or the like, and (b) a second component which is olefinic and which forms at least a portion of the fiber's surface characterized by (b) including at least one grafted olefinic polymer, preferably at least one grafted linear ethylene polymer, having pendant succinic acid or succinic anhydride groups; whereby the fiber is dyeable. The bicomponent fibers made by this process can be in a variety of shapes (e.g., round, oval, trilobal, flat, or hollow) and configurations (e.g., symmetrical sheath/core or side-by-side or asymmetrical crescent/moon). The succinic acid or succinic anhydride groups are provided by grafting, respectively, maleic acid or maleic anhydride onto the linear ethylene polymers especially by a process wherein the grafting is done in a twin-screw, co-rotating extruder with the maleic acid or maleic anhydride being injected into a pressured zone of the extruder. The acid containing grafted linear ethylene polymer or polymer blends are dyeable in contradistinction to ungrafted linear ethylene polymers.

Method for making bicomponent fibers

Extrudable blends of polypropylene and polyethylene, especially LLDPE, are prepared in a dynamic mixer and extruded as novel biconstituent fibers comprising polypropylene as one phase and polyethylene as another phase. Improved tenacity and hand are obtained, as compared to polypropylene alone.

Biconstituent polypropylene/polyethylene fibers

Succinic acid or succinic anhydride grafts of linear ethylene polymers are blended with other polymers or resins, e.g. polyesters and the like, to form blends having useful adhesive properties. The adhesive properties are useful in various laminates and in bicomponent fibers which comprise a core of a performance fiber, especially a polyester such as PET or PBT and polyamides, and a sheath of the grafted LDPE, HDPE or LDPE. The succinic acid or succinic anhydride groups are provided by grafting, respectively, maleic acid or maleic anhydride onto the LDPE, LLDPE, and HDPE, especially by a process wherein the grafting is done in a twin-screw, co-rotating extruder with the maleic acid or maleic anhydride being injected into a pressured zone of the extruder. The acid containing grafted polymer is dyeable in contradistinction to ungrafted polymer.

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Lake Jackson, TX, United States of America

Gene P Young