PRODUCTION OF HIGHLY WATER-SWELLABLE VULCANIZED RUBBER PRODUCT

摘要

PURPOSE:To obtain a vulcanized rubber product which can show a high rate of water swelling and a high degree of water swelling even at a low content of a highly water-absorptive polymer, by adding a highly water-absorptive polymer and a filler containing a specified amount of clay. CONSTITUTION:In producing a water-swellable rubber product by adding a highly water-absorptive polymer to an ethylene/alpha-olefin copolymer or an ethylene/alpha- olefin/nonconjugated diene copolymer; a filler system containing clay in an amount of at least 60wt%, based on the total weight of carbon black and/or a white filler is added. Clays are classified into bentonite of montmorillonite group and other clays typified by kaolin group, and particularly preferred clays which can be used in this rubber product are the latter clays typified by kaolin group because of their good water swellability. Examples of the highly water-absorptive polymers used include saponified ethylene/vinyl ester/acrylate ester copolymers and crosslinked acrylic acid/acrylate salt copolymers.