Rubber like sealing material that swells on contact with water - useful for sealing of joints against water penetration and shows good stability to cycling between wet and dry conditions

摘要

A water swellable sealing material (I) with rubber like properties consists of a matrix, prepd. by reaction of known hydrophilic isocyanate prepolymers (II) with chain extenders (III) such as water, alcohols, or amines and incorporates material known to swell strongly in water. The ratio of (II) to (III) is 1:9 to 9:1. Pref. (I) has a homogenous solid microporous or cellular foam like structure and opt. contains known aq. dispersion or solns. of higher mol.wt. polymers and/or known aq. emulsions of bitumen, asphalt or tar in a ratio of additives to (II) of 1:9 to 9:1, to modify its properties to reduce shrinkage upon drying. (I) opt. contains 1-150% (based on the amt. of binder) of inorganic or organic solid with defined particle size as fillers or fibres and pigments and is processed with a support material such as known fabric or felt, prepd. from inorganic or organic raw materials, or rubber or elastomeric solid or foam. USE/ADVANTAGE - (I) are useful for the sealing of joints against water penetration. (I) have good elasticity, are simple and cost effective to prepare and show good stability to cycling between wet and dry conditions.