| abstract |
The invention provides a novel watertight rubbery sealing material of which the water-swellability is markedly insusceptible to the adverse influence of compression of the material in a dry condition. The watertight sealing material is a shaped and vulcanized body of a water-swellable rubber composition comprising, in a limited proportion, (a) a chloroprene rubber, (b) a highly water-absorptive resin such as a crosslinked polyacrlylic acid in the form of a sodium salt, (c) a rubbery polymer unvulcanizable with a metal oxide-based vulcanizing agent and (d) a metal oxide-based vulcanizing agent which is preferably a combination of magnesium oxide and zinc oxide. |