Thin, smooth nitrile rubber gloves
View Patent ↗A nitrile-rubber medical exam glove composed of a glove body which is a flexible layer of nitrile-butadiene rubber having a chlorinated first surface forming a donning side and an un-chlorinated second surface forming a grip side. The elastomeric glove also includes a substantially uniform distribution of a release agent distributed over the un-chlorinated second surface of the glove body. The elastomeric glove has: (a) an average thickness of between about 0.03 to 0.12 mm in a palm region of the glove body as measured in accordance with ASTM D3767, procedure A; (b) an un-chlorinated second surface of the glove body characterized by a Surface Root Mean Square Roughness of from about 3.00 μm to about 6.55 μm; and (c) a failure rate of less than about 1 percent when the elastomeric glove is subjected to pinhole leak testing generally in accordance with ASTM D5151-06.
1. An elastomeric glove produced by a process comprising:
coating a surface of a mold with a coagulant solution and a release agent, the coagulation solution having a calcium ion concentration of between about 3 percent and about 5 percent based on the weight of calcium ions in the coagulant solution;
partially drying the mold coated with the coagulant solution and release agent;
immersing the partially dried mold into an nitrile-butadiene rubber latex emulsion having a latex solids content of between about 12 percent and about 20 percent, by weight, for a dwell time of between about 7 seconds and 15 seconds to form a layer of coagulated nitrile-butadiene rubber latex on the mold surface;
removing the mold from the nitrile-butadiene rubber latex emulsion;
immersing the mold containing the coagulated nitrile-butadiene rubber latex into an aqueous bath to remove excess calcium ions and then drying the coagulated nitrile-butadiene rubber latex to form a glove body on the mold;
immersing the mold containing the glove body into a chlorinating bath to chlorinate an exterior surface of the glove body on the mold; and
removing the glove body from the mold by inverting the glove body such that the chlorinated exterior surface of the glove body forms an interior surface of the glove body;
the elastomeric glove comprising a glove body consisting of a single, flexible layer of an elastomeric nitrile-butadiene rubber formed from a nitrile-butadiene rubber latex, the glove body having first surface forming a donning side of the glove body and an un-chlorinated second surface forming a grip side of the glove body;
a substantially uniform distribution of a waxy release agent over the un-chlorinated second surface of the glove body;
wherein the glove body has: (a) an average thickness of between about 0.03 to 0.12 mm in a palm region of the glove body; (b) an un-chlorinated second surface of the glove body characterized by a Surface Root Mean Square Roughness (Sq) of from about 3.00 μm to about 6.55 μm; and (c) a failure rate of less than about 1 percent when the elastomeric glove is subjected pinhole leak testing generally in accordance with ASTM D5151 06.
2. The elastomeric glove according to claim 1 , wherein the glove body exhibits a force-to-strain response between zero elongation and 300 percent elongation (F-300) of less than or equal to about 1.50 N at F-300 when tested in accordance with ASTM D412-06.
3. The elastomeric glove according to claim 1 , wherein the glove body exhibits a force-to-strain response between zero elongation and 300 percent elongation (F-300) that ranges from about 1.08 N to about 1.45 N for a thickness of about 0.03-0.10 mm when tested in accordance with ASTM D412-06.
4. The elastomeric glove according to claim 1 , wherein the glove body exhibits a force-to-strain response between zero elongation and 400 percent elongation (F-400) of less than about 2 N at F-400 when tested in accordance with ASTM D412-06, or the glove body exhibits a force-to-strain response between zero elongation and 500 percent elongation (F-500) of less than about 2 N at F-500 when tested in accordance with ASTM D412-06.
5. The elastomeric glove according to claim 1 , wherein the glove body exhibits a force to break of less than about 6.0 N at about 560 percent elongation to about 600 percent elongation of an original dimension when tested in accordance with ASTM D412-06.
6. The elastomeric glove according to claim 1 , wherein the glove body has a surface area to volume ratio of between about 150/cm to about 250/cm.
7. The elastomeric glove according to claim 1 , wherein the un-chlorinated second surface of the glove body is characterized by a Surface Root Mean Square Roughness (Sq) of from about 3.00 μm to about 5.30 μm.
8. The elastomeric glove according to claim 1 , wherein the un-chlorinated second surface of the glove body is characterized by a Surface Average Roughness (Sa) of less than about 3.0 μm.
9. The elastomeric glove according to claim 1 , wherein the un-chlorinated second surface of the glove body is characterized by a pore density ranging from about 820 pores per mm 2 to about 1600 pores per mm 2 as determined by optical image analysis.
10. The elastomeric glove according to claim 1 , wherein the un-chlorinated second surface of the glove body is characterized by a pore density of greater than or equal to about 800 pores per mm 2 as determined by optical image analysis.
11. The elastomeric glove according to claim 1 , wherein the release agent is selected from metallic stearates, petroleum waxes with a melting point of less than about 200° C., natural animal waxes, or synthetic waxes.
12. The elastomeric glove according to claim 1 , wherein the elastomeric glove has a failure rate of less than about 0.5 percent when the elastomeric glove is subjected pinhole leak testing generally in accordance with ASTM D5151-06.
13. The elastomeric glove according to claim 1 , wherein the elastomeric glove has a failure rate of less than about 0.1 percent when the elastomeric glove is subjected pinhole leak testing generally in accordance with ASTM D5151-06.
14. The elastomeric glove according to claim 1 , wherein the elastomeric nitrile-butadiene rubber comprises a terpolymer of acrylonitrile, butadiene, and carboxylic acid in which the acrylonitrile polymer content is about 15 percent, by weight, to about 42 percent, by weight, the carboxylic acid content is between about 1 percent, by weight and about 10 percent by weight, and the remaining portion of the terpolymer composition is butadiene.