Textiles: spinning – twisting – and twining – Strand structure – Covered or wrapped
Reexamination Certificate
1999-07-07
2001-07-17
Calvert, John J. (Department: 3765)
Textiles: spinning, twisting, and twining
Strand structure
Covered or wrapped
C057S210000
Reexamination Certificate
active
06260344
ABSTRACT:
TECHNICAL FIELD
This invention relates to a cut-resistant yarn and apparel made therefrom, specifically a protective glove.
DISCLOSURE OF THE INVENTION
The present invention provides a new and improved yarn that provides both cut-resistance and protection against bacteria that can reside in gloves, especially when used in various food handling industries, and result in an unsanitary condition, or improper washing after using the gloves. The new and improved yarn provides apparel with a softer feel and improved flexibility that is more comfortable to use.
A preferred yarn is suitable in diameter for machine knitting and is flexible enough to be used for making protective gloves. Preferably the yarn is of composite construction utilizing synthetic fibers and cut resistant core material. At least one of the fibers is an acrylic and is coated or impregnated with an antimicrobial chemical.
In its broad aspects, the yarn is comprised of a acrylic fiber strand that contains an anti-microbial chemical and a strand of cut-resistant material and is of a total denier and diameter suitable to be knit on a commercial knitting machine.
In a preferred embodiment for this invention, the knittable cut-resistant yarn comprises a core having at least one strand of a multi filament, cut resistant poly-paraphenylene terephthalamide having a total denier in the range of about 200 to 600 and preferably a denier of about 400 or a stainless steel wire having a diameter in the range of 0.001-0.004 inch and preferably a diameter of substantially 0.002 inches. Poly-paraphenylene terephthalamide, also known as para-aramid, is sold under the trade name KEVLAR. The poly-paraphenylene terephthalamide chains are highly oriented with strong interchain bonding which result in a unique combination of properties, including among others, superior cut resistance. In addition to the use of KEVLAR strands or stainless steel wires, the core may also include other flexible materials, such as fiberglass having a denier in a range of about 100 to about 400. The core strands are substantially parallel and are wrapped by a plurality of synthetic fibers to a final diameter suitable for use in a commercial knitting machine. A first wrap is wound in one direction about the core and a second wrap is wound in an opposite direction to the first wrap. Each subsequent wrap is wound in a direction opposite to the previous wrap. The fibers used in the wraps have a denier in a range from about 70 to about 600. In the preferred embodiment, at least one wrap comprises an antimicrobial ring spun acrylic fiber with an effective denier range from about 200 to about 300.
The wraps are preferably wound about the core at a rate of 7-12 turns per inch. In the illustrated embodiment, the first and second wraps are wrapped at the rate of 8 turns per inch. Additional wraps can be wound about the core and the amounts necessary will be apparent to one of ordinary skill in the art in view of the intended application for the yarn.
In the preferred embodiment, the antimicrobial treated fiber is an acrylic material containing the antimicrobial chemical 5-chloro-2(2,4-dichlorobisphenoxy)phenol. The antimicrobial of this type is sold by the trade name Triclosan. Triclosan is a bisphenol derivative that has bacteriostatic activity against a wide range of gram positive and gram negative bacteria. One example of an acrylic fiber with Triclosan in the polymer fiber matrix is available from Sterling Industries and is sold under the trade name BIOFRESH. The preparation of antimicrobial fibers is known to those skilled in the art. One such procedure involves preparing the fibers having antimicrobial activity by melt spinning the fibers with the antimicrobial agent or by mixing a proper amount of antimicrobial agents in a polymer solution and thereafter spinning the mixture through spinnerates into a coagulating bath to form into fibers. It is preferred to use a fiber wherein the polymer matrix contains the antimicrobial. It has been found that antimicrobial residing on the surface of the fiber wears off during use or is washed off during cleaning of the apparel with soap and other detergents. The use of antimicrobial in the fiber'polymer matrix wherein the antimicrobial resides in the interstices of the matrix serves as a source for surface replenishment of the antimicrobial. It is believed that the antimicrobial filled interstices act as a reservoir from which the antimicrobial can bloom to the surface after a period of time so that antimicrobial that had been worn or washed off the surface is replaced. Thus, it has been found that an effective amount of antimicrobial is present after repetitive use or washing thereby prolonging the use of the glove.
In the illustrated embodiment the core also includes at least one strand of a high strength, cut-resistant fiberglass fiber having a denier in the range of 75-500 and preferably has a denier of about 300.
The yarn described above can be used to make protective gloves of the type that are used in the food handling industry. It has been found that the gloves made according to the invention are softer and more flexible than other gloves of this type and are still capable of dealing with bacteria that comes in contact with the glove. Moreover, the use of acrylic fibers in combination with other polymeric materials, such as but not limited to, KEVLAR, high density polyethylene and fiberglass or stainless steel, results in a cut and bacteria resistant glove that is softer and more comfortable to use with unexpectedly improved gripping power. In the preferred construction, the antimicrobial treated acrylic fiber is used as wraps rather than a core of the composite yarn. The antimicrobial acrylic fibers have good strength and durability to comprise all of the wrap layers or are located in the intermediate wrap layers of the yarn composite. Other polymeric synthetic fibers such as nylon, polyester or high density polyethylene can also be used in addition to the antimicrobial treated acrylic fibers. The antimicrobial treated acrylic fibers are relatively expensive compared to untreated fibers and as such, it is preferred that the amounts of antimicrobial treated acrylic fibers in a yarn composite range from about 15% to about 50% of the total yarn weight. Higher amounts can be used but the use of higher amounts is not cost effective. More preferably, the amount of antimicrobial used in the yarn composite is about 20% of the total yarn weight. Each fiber preferably comprises 0.5% to 2.0% antimicrobial agent Triclosan of the total weight of the fiber. The amounts used for other antimicrobial agents in fibers will vary depending on the properties of the agent and will be apparent to those skilled in the art.
The use of acrylic fibers for knitting gloves result in a softer and more comfortable fitting glove. Furthermore, it has been found that gloves made from these yarn composites exhibit good durability and demonstrate improved gripping power over prior art gloves.
It is believed that by using the antimicrobial treated spun acrylic fiber as wraps instead of as a core provides a softer glove with improved gripping ability. If the yarn, for example, is used to make a glove used in the food handling and processing industry, bacteria is transmitted to the glove when the outside of the glove makes contact with fluids and solutions encountered in processing or handling food, such as meat. As a result of capillary action, these fluids migrate quickly towards the center of the yarn. The bacteria is carried towards the center of the yarn with fluid. Once the bacteria makes contact with the anti-microbial treated fiber, its growth and propagation is inhibited. General washing of the gloves after use is recommended for removal of all contaminants. With the preferred construction, washing the glove with appropriate detergent and water will remove most of the bacterial contamination from the surface of the glove, and the core of the glove will also be free of bacteria due to the presence of the antimicrobial agent in close proximit
Calvert John J.
Watts, Hoffmann, Fisher & Heinke Co.
Welch Gary L.
Whizard Protective Wear Corp.
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