Synthetic fibers modified with PTFE to improve performance

Abstract

Synthetic plastic fibers are enhanced by inclusions therein of micro-polyester particles (4), preferably sized or otherwise optimized to enhance surface (10) characteristics (abrasion resistance, hydrophilicity, coating receptiveness, increase dullness), reduce UV degradation. The synthetic plastic matrix is preferably polyester but can be any synthetic plastic. The invention is preferentially implemented in multi-component fibers (e.g. core (6)-sheath (8) bi-component fibers (3)) with the inclusions entirely or primarily in one or some, but not all such components. The PTFE inclusions, sizing, concentration, morphology can be adjusted to optimize their enhancing effects, reduce costs and enhance throughput of fiber production. Co-inclusions can be made with the PTFE including anti-microbial and / or coloring agents and with synergistic effects.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 60 / 495,583 filed Aug. 15, 2003, the contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION [0002] Synthetic fibers have been produced with various additives to achieve certain characteristics, such as pigment additives to obtain desired colors. Certain polymers present difficulties, however, in achieving optimal performance. Many polyesters such as, for example, PET (polyethylene teraphthalate), have poor ultraviolet (UV) resistance characteristics and are hydrophobic. Many PET polymers also suffer from poor abrasion resistance and have a tendency to pill during abrasion. SUMMARY OF THE INVENTION [0003] Synthetic fibers such as polyester, polyolefins (e.g., polypropylene), nylon, acrylics and others in either mono-component or multi-component matrix configurations (e.g., core / sheath, two side-by-side or pie-...

AI Technical Summary

Benefits of technology

[0003] Synthetic fibers such as polyester, polyolefins (e.g., polypropylene), nylon, acrylics and others in either mono-component or multi-component matrix configurations (e.g., core / sheath, two side-by-side or pie-wedge forms) can be significantly improved by the inclusion (or micro-inclusions) therein of PTFE (polytetrafluoroethylene) of appropriate particle sizes to improve UV resistance, increase the dullness (reduce sheen), modify the surface of the fibers to improve hydrophilicity, improve abrasion resistance, and as a processing aid to increase production outputs. In multi-component configurations, the PTFE inclusions may be incorporated into one, some or all of the components comprising the enhanced fiber. In core-sheath bi-component configurations, the PTFE particles are substantially all included in the sheath component so as to assure particle presence at or near the external surface of the fiber in order to obtain the optimum desired effect. It is also preferred to dimension the thickness of the sheath in such configurations to approximate the inclusion size.

[0005] Methods in accordance with the present invention generally involve adding the PTFE particles to the PET or other synthetic plastic matrix fiber, but preferably concentrate the added PTFE particles near the fiber surface. The fibers may be produced by extrusion or other processes that result in striations and other voids at the fiber surface. This structure, together with the presence of the PTFE particles proximate the fiber surface, favors hydrophilicity, stain and water resistance and enhanced substrate conditions for bonding coatings mechanically and chemically, particularly PTFE coatings. Through these techniques, enhancement of fiber and / or fabric dullness and resistance to abrasion can be achieved.

[0006] The concentrations, sizing, and regional placement (in a fiber and / or fabric) of inclusions are controllable during production to reduce UV degradation of the fibers and / or at a minimum the components of the multi-component fibers incorporating the inclusions. The enhancement of UV resistance by the composite fiber is enhanced when the PTFE particles have at least one cross-sectional length dimension about equal to a materially important wavelength (one responsible for UV degradation) within the UV spectral region (˜10-400 nm.) The UV resistance effects are enhanced when PTFE and inorganic pigment particles (e.g., titanium dioxide) are provided as co-inclusions.

[0007] The present invention enhances the suitability of polyester fibers for such applications as convertible tops (as well as similar tops for boats, umbrellas, awnings, fabric shades as well as vehicle interiors), automobile carpeting and other similarly challenging carpeting, clothing (due to reduced sheen and wicking properties, making polyester fibers competitive with natural fibers) and like fabric applications such as table cloths and bedding, curtains. The PTFE particle sizing is preferably 0.1 to 1.0 μm for UV resistance, but on the order of 5-20μ (preferably about 15μ) for some of the heavy duty carpeting applications. The particles are preferably spherically or nearly spherically shaped when employed to enhance UV resistance. The enhanced fibers can be staple fibers or mono-filaments.

Problems solved by technology

Certain polymers present difficulties, however, in achieving optimal performance.

Many polyesters such as, for example, PET (polyethylene teraphthalate), have poor ultraviolet (UV) resistance characteristics and are hydrophobic.

Many PET polymers also suffer from poor abrasion resistance and have a tendency to pill during abrasion.

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