||January 1, 2006
The rapidly increasing cost of energy needed to produce high-volume dip-molded or cast latex products, such as medical gloves and other dip-molded or cast rubber film products of natural rubber or synthetic polyisoprene, is of concern to the latex industry. The use of rubber accelerators, the formation or presence of Type IV latex allergens, nitrosamine formation, and excessive energy usage are still of concern to the industry. The method of latex film vulcanization discussed in this paper reveals how a specific class of curing agents can effectively address these issues. These curing agents, known as polynitrile oxides, can rapidly vulcanize latex films at only modestly elevated temperatures, or even at room temperature or below. It is only necessary to dry the latex films on the production line, eliminating or greatly reducing the need for an in process heated curing step. This can save much energy and can increase production capacity. No post-stripping cure is needed, as full cure occurs at room temperature over time without concern for under-curing or over-curing. The cured articles are clear, free of sulfur, activators, accelerators, nitrosamines, nitrosatables, and odors. As compared to alternative accelerator-free methods, they have superior physical properties, including improved tear and tensile strengths and ultimate elongation. Tear strength of up to 70 kN/m, tensile strengths of up to about 6000 psi, and ultimate elongations in the range of about 550 % to about 1200 % have been achieved. It is not necessary or desirable to prevulcanize. It is also not necessary to use any specialized production equipment.