Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2000-12-04
2002-11-12
Morris, Terrel (Department: 1771)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S293100, C428S293400, C428S296400, C428S364000, C428S365000, C428S372000, C428S375000, C428S380000, C428S381000, C428S384000, C428S385000, C428S389000, C442S123000, C442S124000, C424S417000, C424S421000, C424S443000, C424S444000, C424S445000, C424S446000, C424S447000, C424S608000, C424S618000
Reexamination Certificate
active
06479144
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to polyurethane elastomer fibers (particularly spandex) containing certain silver-based antimicrobial formulations therein. Such formulations comprise antimicrobial compounds, such as, preferably, triclosan and/or silver-containing ion-exchange resins, such as zirconium phosphate, glass, or zeolite compounds. The inventive spandex fibers exhibit excellent antimicrobial qualities as well as surprisingly good anti-tack/frictional characteristics. As a result, antimicrobial spandex fibers are provided which exhibit ease in processing, particularly in further knitting, weaving, etc., to produce fabrics therefrom. Such fabrics are also encompassed within this invention.
DISCUSSION OF THE PRIOR ART
All U.S. Patents listed below are herein entirely incorporated by reference.
There has been a great deal of attention in recent years given to the hazards of bacterial contamination from potential everyday exposure. Noteworthy examples of such concerns include the fatal consequences of food poisoning due to certain strains of
Eschericia coli
being found within undercooked beef in fast food restaurants; Salmonella contamination causing sicknesses from undercooked and unwashed poultry food products; and illnesses and skin infections attributed to
Staphylococcus aureus, Klebsiella pneumoniae
, yeast, and other unicellular organisms. With such an increased consumer interest in this area, manufacturers have begun introducing antimicrobial agents within various everyday products and articles. For instance, certain brands of polypropylene cutting boards, liquid soaps, etc., all contain antimicrobial compounds. The most popular antimicrobial for such articles is triclosan. Although the incorporation of such a compound within liquid or certain polymeric media has been relatively simple, other substrates, including the surfaces of textiles and fibers, have proven less accessible. Such compounds are highly desired for fibers and fabrics in order to provide not only antimicrobial benefits, but also mildew and odor control properties.
There thus a long-felt need to provide an effective, durable, reliable antimicrobial spandex fiber which provides such long-term effects. Of additional importance is the need to provide such specific fibers that facilitate, or, at the very least, permit further processing into desired fabrics. Thus, such a desirable fiber must exhibit suitable anti-tack properties thereby permitting continuous utilization without appreciable obstacles to weaving, knitting, and the like, due to cohesion with other spandex fibers or adhesion to process machinery components. In the past, such anti-tack properties have been provided through the incorporation of different compounds, such as metallic soaps (U.S. Pat. No. 4,296,174 to Hanzel et al.), fiber surface finishes, and the like. However, such compounds do not provide antimicrobial characteristics as well.
Other antimicrobial spandex fibers have been produced of the sheath-core type (Japanese Patent Application 6-146112 to Kawanabe) with the antimicrobial agent utilized within the sheath portion. However, such fibers are of the sheath-core variety that relies primarily on the elasticity of the core component for its ultimate function. There have been no teachings of such antimicrobial spandex fibers wherein the antimicrobial component is dispersed substantially throughout the target fiber itself. As such, there are definite differences and improvements upon utilization of complete antimicrobial fibers rather than such sheath-core types. For instance, it is important to realize that spandex fibers are not always utilized as in complete form from initial production. The fibers themselves are generally either cut for insertion within discrete areas of target fabrics or, upon incorporation within fabrics (e.g., knit, woven, non-woven, and the like), are cut for further insertion as fabric components within other fabrics. In such an instance, sheath-core yams do not provide any appreciable increase in antimicrobial activity from standard initial production to “cut” configuration. By contrast, single-component yams exhibiting antimicrobial compounds dispersed throughout provide desirable improvements in antimicrobial characteristics upon being cut since more antimicrobial is exposed.
Another important distinction lies in the potential for moisture to mobilize the antimicrobial compounds within the target fibers. Spandex, being a polyurethane, is somewhat hydrophilic and draws moisture readily from the surrounding atmosphere. Upon such moisture regain by the target fibers, a silver-based antimicrobial (as one example) can exhibit migration of silver particles within and possibly to the surface of the target fiber. With a sheath-core configuration, the potential for relatively quick loss of such particles by moving to the surface (and subsequently removed by friction, etc.) is quite high, considering the short distance required to reach such a destination. However, a single component spandex fiber will not exhibit such high probabilities of rapid antimicrobial loss because of the greater amount of antimicrobial therein and thus the greater distance required for movement to the surface.
Furthermore, with regard to silver-based inorganic antimicrobial materials, sheath-core fiber configurations are not particularly suitable for full efficacy thereof. For example, it has been found that certain silver-based ion-exchange compounds (such as ALPHASAN® brand antimicrobials available from Milliken & Company) exhibit regenerable characteristics for antimicrobial properties. After a period of time, the silver solids become depleted through bactericidal activity; however, upon frictional contact with the substrate surface, new, unused silver components are brought to the surface, thus providing a regenerable antimicrobial source. With a sheath-core configuration, the sheath itself is so thin that the amount of silver particles present therein is very limited. Thus, the antimicrobial lifetime of such a fiber is itself rather limited since very little extra silver particle source is available in such an instance. To the contrary, an entire fiber comprised of such silver particles will theoretically provide long-lasting, renewable antimicrobial properties.
Additionally, sheath-core configured fibers have proven to be impractical from an industrial production standpoint as well. Sheath-core fiber configurations are limited to production by melt-spun processes. Most spandex fibers, however, are produced via solution-spun processes. Hence, sheath-core types are not widely available. Also, it is very difficult and expensive to uniformly produce sheath-core yarns due to the equipment required and/or available. The trouble inherent with controlling the sheath placement around the core is extremely difficult to handle on a large-scale level and thus limits production speeds.
Thus, there is a need to provide long-lasting antimicrobial spandex fibers for incorporation within apparel and other fabrics that exhibit proper antimicrobial characteristics and is likewise processable into such fabrics, and the like. Unfortunately, to date, no such particular spandex fibers, or antimicrobial fabrics encompassing such fibers, has been accorded the apparel and fabric industries by the pertinent prior art.
DESCRIPTION OF THE INVENTION
It is thus an object of the invention to provide a spandex fiber comprising silver-based inorganic antimicrobial throughout said fiber. It is further object of the invention to provide a fabric article comprising such spandex fibers, and more particularly an apparel article comprising same. Yet another object of the invention is to provide a spandex fiber (such as above) that exhibits excellent processability within fabric producing machines (e.g., weaving looms, knitting machines, and the like), such that said spandex fibers exhibit extremely low, if not nonexistent, levels a cohesion between different portions of individual spandex fibers or between portions of different spandex fibers. A further
Close, Jr. Leland G.
Petrea Randy D.
Schuette Robert L.
Whiteside Shirley Anne
Milliken & Company
Morris Terrel
Moyer Terry T.
Parks William S.
Singh Arti R.
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