Stock material or miscellaneous articles – Hollow or container type article – Polymer or resin containing
Reexamination Certificate
2000-04-18
2003-10-28
Nolan, Sandra M. (Department: 1772)
Stock material or miscellaneous articles
Hollow or container type article
Polymer or resin containing
C428S036800, C428S423900, C428S424200, C428S424700, C428S424800, C428S451000, C524S506000, C524S591000
Reexamination Certificate
active
06638587
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to elastomeric articles used in medical applications. In particular, the invention pertains to elastomeric articles such as medical gloves having reduced coefficient of friction with respect to the skin-contacting surface.
BACKGROUND OF THE INVENTION
Surfaces of elastomeric articles generally exhibit poor lubricity when contacting a dry surface, such as dry skin or other mammalian tissues, as a result of surface friction. In addition, many elastomeric surfaces display poor lubricity when contacting a damp surface as well. This is primarily due to a high coefficient of friction, or COF, of the elastomeric surface. Surfaces of elastomeric articles which exhibit a high coefficient of friction when sliding against another surface can be disadvantageous in uses where ease of donning and removal are beneficial to the use of the article. This property plays an important role in the use of medical gloves, such as examination and surgical gloves, where mechanical properties, tear resistance and tactile sensitivity during use are also beneficial features. Surgical gloves fabricated from natural rubber latex, for example, are difficult to don due to the high coefficient of friction between the glove material and the skin.
Various methods and techniques to improve the donning of gloves by reducing the coefficient of friction have been explored in the art. One such technique that has been employed is the use of talc or powders, such as calcium carbonate and starch, applied to the gloves during manufacture. Chemical methods have been explored as well to decrease the coefficient of friction of glove surface. One such method involves the halogenation of the surface of an elastomeric material to increase lubricity. However, halogenation techniques such as chlorination can adversely affect desirable mechanical properties of the material in articles such as gloves if the halogenation process is not well controlled.
A number of approaches to increase the lubricity of elastomeric articles (e.g., gloves) have been explored in the art, such as techniques using polymeric coatings, particulate micro-roughening of the surface, or combinations of both. Lubricant compositions containing silicone derivatives have been disclosed in U.S. Pat. No. 5,742,943 to Chen, which teaches flexible articles such as surgical gloves containing an elastomeric substrate layer having an elastomeric material which has been treated with a lubricant composition containing organo-modified silicone and amino-modified silicone compounds. U.S. Pat. No. 5,534,350 to Liou discloses a powder free glove containing an elastomeric layer with increased lubricity which has been treated with an aqueous dispersion of polyurethane together with a silicone emulsion. In medical applications, silicone has been widely used because of its lower surface energy, biocompatibility, e.g, high chemical and contamination resistance, and flexibility.
The use of polymeric surfaces embedded with microparticles to improve donning of gloves is known. See U.S. Pat. No. 5,792,531 to Littleton et al., for example. U.S. Pat. Nos. 5,405,666 and 5,395,666 to Brindle disclose an elastomeric glove with increased lubricity having a polymeric binding layer containing a surfactant and partially-protruding microparticles which produce a microroughening effect on the skin-contacting surface. U.S. Pat. Nos. 5,272,771 and 5,088,125 to Ansell et al. disclose an elastomeric glove with increased lubricity having a layer containing an ionic polyurethane in combination with particulate polyurethane, including acrylate or methacrylate co-polymers. U.S. Pat. No. 4,070,713 to Stockum discloses an elastomeric glove having a layer containing a binder and particulate microspheres. The binder can be composed of carboxylated styrene butadiene latex, and the particles can be composed of polyethylene, ethylenevinyl acetate co-polymers or epichlorohydrin cross-linked cornstarch.
There still exists the need for elastomeric articles such as medical gloves having improved donning properties while retaining the desirable mechanical and chemical properties associated with elastomeric articles. There is also a need in the medical community for powder-free medical gloves that avoid the disadvantages of conventional lubricity increasing techniques.
SUMMARY OF THE INVENTION
Applicants' invention is directed to an improved elastomeric article composed of a flexible, elastomeric material and a composite coating comprising a silicone-modified polymer in combination with silicone resin particles, and to a method of making such an article. It has been discovered by applicants that the chemical interaction between silicone-based polymers and silicone resin particles can be used to produce a coating which possesses a significantly reduced coefficient of friction, thereby improving the lubricity and donning properties of the article. The interaction between the siliconized polymer and particles enhance the binding of the particles and permit very thin coating layers to be applied to articles while still maintaining surface microroughness. Articles made according to the invention exhibit extended use without significant disassociation of the particles from the coating through wear. The invention is particularly useful as applied to elastomeric articles such as medical gloves (e.g., examination and surgical gloves) where donning or skin-contacting properties with respect to both dry and damp surfaces have historically been problematic.
In particular, the invention is directed to an elastomeric article having an elastomeric material and a coating layer adhered (e.g., bonded, fused, coupled) thereto and containing a composite comprising:
a) a silicone-modified polymer; and
b) silicone particles embedded and integrated throughout said polymer;
wherein said coating layer is on a contacting surface of the article.
Elastomeric articles, such as surgical gloves, containing the coating layer and made according to the invention exhibit a topographically microroughened surface having a reduced coefficient of friction and improved lubricity and donning properties without the need for use of powders. The interaction between the components in the coating layer as well as the thickness of the coating layer and the ratio of polymer to particle collectively function to optimize the desirable properties of the article. Typically, the coating layer is applied to that surface of the article which will come into contact with skin when in use. In the case of a glove, the coating layer is on the interior surface of the glove when worn and absent from the exterior surface.
The elastomeric material used in the article can be composed of any natural or synthetic polymeric material which exhibits mechanical and chemical properties appropriate for the intended use of the article. In the case of surgical gloves, the elastomeric material must be flexible and tear-resistant with sufficient elongation and strength properties, and accommodate the tactile sensitivity requirements for gloves used in surgical procedures. Suitable elastomeric materials include, but are not limited to, those polymeric materials containing natural or synthetic rubber, polyurethane, conjugated diene homopolymers, conjugated diene co-polymers, conjugated diene and vinyl monomer copolymers, styrene block co-polymers (di-block and tri-block), and combinations thereof.
The coating layer adhered to the elastomeric material is a composite comprising a silicone-modified polymer in combination with silicone resin particles integrated and embedded therein. Any silicone-modified polymer which can adhere to the particular elastomeric material used and which can function to bind the silicone resin particles to a degree sufficient to inhibit detachment or delamination of the particles from the silicone-modified polymer, can be used. Silicone-modified polymers which can be used include those polymeric structures which can have silicone groups covalently attached to the chemical structures. Suitable silicone-modified polymers
Wang Shiping
Yeh Yun-Siung Tony
Allegiance Corporation
Nolan Sandra M.
Rozycki Andrew G.
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