Soft nitrile medical gloves having improved glove relaxation properties
View Patent ↗The invention is the manipulation of the zinc oxide content and sulfur content of nitrile butadiene rubbers and selected vulcanization conditions that can be achieved economically with common production facilities. The manipulation of these components affects the relaxation property of gloves formed by this material. Produced are gloves that have a relaxation property, higher than 50%, and a low modulus (approximately 3 Mpa). The glove maintains decent ultimate tensile strength (>20 Mpa) and elongation (>500%). The glove is produced by a vulcanization process, which lasts from 5 to 60 minutes at temperatures ranging from 300° F. to 400° F. The tensile strength and elongation are well above the ASTM requirements for medical gloves. The current ASTM requirements are ASTM D412-92. Thanks to sufficient vulcanization, the films produced provide satisfactory protection from viral penetration. The tearing strength is also better because of the lower modulus.
1. An elastomer formulation for a glove comprising:
a nitrile butadiene rubber latex;
Sulfur ranging from about 2 to about 5 parts per hundred parts of the nitrile butadiene rubber latex; and
Zinc oxide, said zinc oxide, present in an amount greater than 0.5 parts per hundred and less than 1.0 parts per hundred parts nitrile butadiene rubber, wherein said elastomer has a relaxation property greater than 50%.
2. The elastomer formulation for a glove as claimed in claim 1 , further comprising:
a secondary accelerator ranging from 0.5 to about 2 parts per hundred parts of the nitrile butadiene rubber latex.
3. The elastomer formulation for a glove as claimed in claim 2 , wherein the secondary accelerator is selected from the group consisting of: zinc dibutyldithiocarbamate; zinc diethyldithiocarbamate; and zinc 2-mercaptobenzothiazole.