Moisture crosslinking process for foamed polymers

Alkoxysilanes can be grafted onto an ethylene homopolymer or copolymer to g ive a moisture crosslinkable polymer. Moisture crosslinking has many benefi ts over peroxide- or irradiation-induced crosslinking. Simple, conventional equipment allows processing with lower capital investment and less manufac turing space. The moisture crosslinking process permits conventional thermo plastic processing after the initial grafting process to give greater flexi bility in the types of applications for this crosslinking technique. In foa ming processes, silane crosslinking is compatible with most types of conven tional blowing agents and other additives. The combination of silane crossl inking with metallocene polyethylene technology has given rise to a broad r ange of crosslinked polyolefin materials, including flexible, rigid, open, and closed cell foams. Good quality foams with very low densities, approach ing 1 lb/ft(3) (16 kg/m(3)), are possible. The advantages of silane crossli nking technology have opened many new markets for polyethylene foams.