Dispersion of polyethylene imine-coated chopped fibers in rubber matrix

摘要

Resorcinol formaldehyde latex(RFL)dip has been used for decades as the coating of choice for fibers and fabrics used for rubber reinforcement.Recently,many studies have indicated that the formaldehyde in RFL has potential health and environmental problems(refs.1-5).In addition to the hazards RFL poses to humans,RFL also requires multiple processing steps to produce.These steps require a great deal of effort to prepare and costly time to dip-coat fibers or fabrics for rubber reinforcement.Recently,many research activities have been focused primarily on developing alternative treatments that are formaldehyde-free systems that deliver acceptable coatings on fibers.For practitioners to readily accept such alternative technology,the goal must be to use the same or similar dipping equipment used in RFL dip coating programs.Louis et al.discussed formaldehyde-free dip technology introduced by Kordsa Group for reinforcing textile materials(ref.6).This technology consists of epoxy,polyisocyanate and latex,which were proportionately blended into a dipping solution(ref.7).The objective was to replace the traditional RFL dipping chemistry and still be able to use the traditional dipping equipment.Gomes et al.evaluated RFL-free coatings of tire textiles which they compared to an RFL system for various fiber materials;the RFL-free coating consisted of Ricobond 7004 from Cray Valley and other ingredients(ref.8).Ricobond 7004 is a dispersion of a functionalized polymer.The results were reported to be comparable to the RFL system,but with lower peel forces.Bridge-stone(ref.9),as part of its broad and comprehensive Eco-Ac-tivities program,is involved in the development of RFL-free coating systems.Mehler Engineered Products has recently announced an RFL-free dip coating for various fibers(ref.10).