US 6,358,580 B1 · Sealing material which swells when treated with water

Abstract

The invention relates to an optionally foamed sealing composition for preformed seals which can swell when treated with water. The invention also relates to a method for the production thereof out of natural rubber and/or elastomers with a matrix comprised of natural rubber/elastomer components and particle-shaped water absorbing material stored therein. The water absorbing material is a combination of (A) polysaccharide(s) selected from cellulose, starch, starch derivatives removed from grafted starch, amylose, amylopectin, dextran, pectin, inulin, chitin, xanthan, alginic acid, alginates, carrageenan, pustulan, callose, laminarin, guluronic acid, pullulan, lichenin or mixtures of the same with (B) a highly water absorbent synthetic polymer selected from polymers based on (meth)acrylate, poly(meth)acrylic acid and the salts thereof, polyacrylamide, polyalcohols or copolymers of said synthetic polymers. The invention also relates to additional cross-linking and processing auxiliary agents and to property improving agents. It is possible to securely seal superstructures, substructures, tunnels and canals with the assistance of the inventive sealing compositions.

Claims28

Dependent claims

A water-swellable seal composition for preformed seals comprising:

a matrix of an elastomer component and embedded particulate water-absorbent material which water-absorbent material is the combination of;
(a) a polysaccharide selected from the group consisting of microcrystalline cellulose, amorphous cellulose, starch, starch derivatives except grafted starch, amylose, amylopectin, dextrans, pectins, insulin, chitin, xanthan, alginic acid, alginates, carragheenan, pustulan, callose, laminarin, guluronic acid, pullulan, lichenin and mixtures thereof;
with
(b) a water-superabsorbent synthetic polymer selected from the group consisting of polymers based on (meth)acrylate, poly(meth)-acrylic acid and salts thereof, polyacrylamide, polyalcohols, copolymers thereof, and mixtures thereof;
wherein the seal composition is foamed by means of a blowing agent and heated to 100° C. or higher and whereupon the elastomer component is crosslinked.

2 more elements

A process for producing a preformed seal which swells under the action of water, from a seal composition, which seal composition includes a matrix of an elastomer component and an embedded particulate water-absorbent material, wherein the water-absorbent material is a combination of a polysaccharide selected from the group consisting of microcrystalline cellulose, amorphous cellulose, starch, starch derivatives except grafted starch, amylose, amylopectin, dextrans, pectins, insulin, chitin, xanthan, alginic acid, alginates, carragheenan, pustulan, callose, laminarin, guluronic acid, pullulan, lichenin, and mixtures thereof, with a water-superabsorbent synthetic polymer selected the group consisting of polymers based on (meth)acrylate, poly(meth)-acrylic acid and salts thereof, polyacrylamide, polyalcohols, copolymers thereof, and mixtures thereof, said process comprising the steps of:

a) mixing the elastomer component, the water-absorbent material and an optional blowing agent to form the seal composition;
b) forming the seal composition into preformed seals having one or more cross-sections, wherein during the forming step the seal composition is foamed by the blowing agent;
and
c) heating the preformed seal to 100° C. or higher to crosslink the elastomer component whereupon the volume increase of said preformed seal upon exposure to water is 5% to 600% by volume.

1 more element

Dependencies are inferred from the claim text.

Sealing material which swells when treated with water

Life of this patent

Sealing material which swells when treated with water

Life of this patent

Abstract

Claims28