Apparel – Hand or arm coverings – Gloves
Reexamination Certificate
2001-06-27
2002-02-12
Calvert, John J. (Department: 3765)
Apparel
Hand or arm coverings
Gloves
C002S159000, C002S164000, C002S161700
Reexamination Certificate
active
06345394
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
This invention relates to a rubber glove and a process for producing the rubber glove.
The rubber glove of the present invention has an inner covering layer, bonded to a main rubber layer of the rubber glove, which inner covering layer contains resin particles partially exposed on the skin-contacting surface thereof. This rubber glove can be easily donned and put off by the partially exposed resin particles, which do not easily fall off or do fall off only to a very slight extent when the rubber glove is donned or pulled off, and, when the inner covering layer is placed in contact with each other, the layer does not easily stick to each other.
(2) Description of the Related Art
The surfaces of rubber gloves made of natural rubber or synthetic rubber are sticky and not slippery. Especially when the skin-contacting inner surface of a rubber glove is not slippery, the glove cannot be easily donned and put off. To facilitate donning and putting off of the glove, a loose dusting powder is applied onto the skin-contacting inner surface. However, the applied dusting powder easily falls of f upon donning or putting off the glove or during the use thereof, and, when the glove is used in a medical field including surgery, the falling dusting powder may contaminate an operated part and cause postoperative complications.
A proposal has been made wherein the skin-contacting inner surface of a glove is subjected to a chlorination treatment to form protrusions thereon making it slippery. This proposal has problems such that the treating process is difficult to control, the donning and putting-off properties cannot be enhanced to the desired extent, and the use of chlorine may cause environmental pollution.
Another proposal has been made wherein a slippery inner layer comprising a lubricant and a binder is formed on the skin-contacting surface of a rubber glove. In contrast to the powdered rubber glove wherein a loose dusting powder is physically adsorbed on the inner surface thereof, a rubber glove having the inner slippery layer has a benefit such that the inner slippery layer is bonded to the inner surface of the glove by a binder and thus, the lubricant does not easily fall off. For example, a medical rubber glove has been proposed in U.S. Pat. No. 4,070,713, which has an inner lubricating layer formed from a latex of carboxylated styrene-butadiene rubber having dispersed therein starch. A rubber glove has been proposed in Japanese Unexamined Patent Publication (hereinafter abbreviated to “JP-A”) No. H11-61527, which has an inner lubricating layer prepared from an aqueous dispersion comprising a synthetic rubber latex, which is incapable of being coagulated with a coagulant contained in a main rubber layer of the rubber glove, said rubber latex being blended with an organic filler such as a crosslinkable polymethyl methacrylate. These proposals provide an improvement in the donning and putting-off properties, but, the improvement achieved is still not to the desired extent. Further, adhesion of the lubricant used, i.e., starch or an organic filler such as a crosslinked polymethyl methacrylate to an elastomer formed by drying of the rubber latex, is weak and thus, the lubricant tends to fall off.
Another rubber glove has been proposed in JP-A H8-294,930 which is made by a process comprising dipping a glove form in a rubber latex formulation to form a first rubber layer on the glove form, and then, dipping the glove form having the first rubber layer in a rubber latex formulation comprising finely divided particles of a thermoplastic resin such as an ethylene-acrylic acid copolymer resin, a rubber latex, and a blocked isocyanate, to form a second rubber layer, which constitutes an inner lubricating resin particle-containing layer of the rubber glove. By the use of a blocked isocyanate, adhesion of the thermoplastic resin particles to an elastomer derived from the rubber latex is enhanced, but, adhesion of the second rubber layer, i.e., the inner lubricating resin particle-containing layer, to the first rubber layer is poor and thus, the inner lubricating resin particle-containing layer tends to be separated from the first rubber layer.
SUMMARY OF THE INVENTION
In view of the foregoing prior art, a primary object of the present invention is to provide a rubber glove having an inner layer containing resin particles partially exposed on the skin-contacting surface thereof, which glove can easily be donned and put off, and the resin particles contained in the inner layer do not fall off, or do fall only to a very slight extent when the glove is donned or put off, and, when the inner resin particle-containing layer is placed in contact with each other, the layer does not easily stick to each other.
In accordance with the present invention, there is provided a rubber glove comprising a main rubber layer and an inner covering layer, bonded to the main rubber layer, said inner covering layer being formed from a coating composition comprising a polymer latex and resin particles dispersed in the polymer latex; said resin particles being partially exposed on the skin-contacting surface of the inner covering layer to an extent such that, among resin particles visually observed in unit area of the skin-contacting surface of the inner covering layer, resin particles having a maximum particle diameter in the range of 2 to 20 &mgr;m have a total projected area ratio A in the range of 5% to 50%, as defined by the following formula (1):
Total projected area ratio A(%)=B/C×100 (1)
where B is total projected area of the resin particles with a maximum particle diameter of 2 to 20 &mgr;m, and C is the unit area.
In accordance with the present invention, there is further provided a process for producing a rubber glove comprising a main rubber layer and an inner covering layer, bonded to the main rubber layer, which comprises the step of coating one surface of a rubber glove having a main rubber layer, with a coating composition comprising a polymer latex and resin particles dispersed in the polymer latex, to form a resin particle-containing inner covering layer on the surface of the rubber glove; the thus-formed inner covering layer having the resin particles, which are partially exposed on the skin-contacting surface of the inner covering layer to an extent such that the above-mentioned total projected area ratio A of the resin particles, represented by the formula (1), is satisfied.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The rubber glove of the present invention comprises a main rubber layer constituting the glove proper, and an inner covering layer, bonded to the main rubber layer. The inner covering layer is formed from a coating composition comprising a polymer latex and resin particles dispersed in the polymer latex.
The method for forming the main rubber layer constituting the glove proper is not particularly limited, and the main rubber layer is formed from natural rubber latex, synthetic rubber latex, or a mixed rubber latex thereof by conventional dip-forming methods which include, for example, straight dipping, coagulation dipping and dry heat dipping.
The thickness of the inner covering layer is not particularly limited, but it is preferably in the range of 0.1 am and 10 &mgr;m. When the thickness is smaller than 0.1 &mgr;m, resin particles tend to fall off from the inner covering layer. In contrast, when the thickness is larger than 10 &mgr;m, resin particles are liable to be buried within the inner covering layer, and thus, the donning and putting-off of the glove become difficult and the inner covering layer readily sticks to each other. By the term “thickness of the inner covering layer” used herein, we mean the thickness as measured at a part of the inner covering layer, in which part resin particles are not exposed on the skin-contact surface thereof, and which part is predominantly comprised of a polymer latex.
The resin constituting resin particles contained in the inner covering layer usually has a glass transition tempera
Inoue Toshihiro
Nakamura Misao
Calvert John J.
Muromoto Robert H.
Zeon Corporation
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