| 摘要 |
PURPOSE:To provide a moisture-absorbing olefin resin foam material containing a water-absorbing polymer, having high expansion ratio and excellent moisture- absorptivity and cushioning property, free from permanent set, suitable as a joint compound, etc., for construction and building, a packing material, etc. CONSTITUTION:(A) An olefin resin (e.g. medium or low-pressure polyethylene, high-pressure polyethylene, ethylene-vinyl acetate copolymer, etc.) is compounded with (B) a water-absorbing polymer (e.g. graft copolymer of starch and acrylic acid salt, crosslinked carboxymethyl cellulose, etc.), (C) a foaming agent (e.g. azobisisobutyronitrile, azodicarbonamide, etc.) and, if necessary, (D) a foaming assistant, a heat-stabilizer, a photostabilizer, a filler, etc. The resin composition is extrusion-foamed to produce a foam material having desired shape or is thermoformed to a sheet, etc., at or below the decomposition temperature of the foaming agent and the obtained unexpanded product is crosslinked and foamed to obtain the objective moisture-absorbing foam material.
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