| abstract |
Polyurethane-polyurea gel prepn., by reacting NCO gp.-contg. prepolymers (I) with chain extenders in water and/or alcohols, takes place by using, as (I), reaction products of (1) OH gp.-contg. polyethers contg. >40 wt. % C2H4O-units with (2) polyisocyanates, in NCO/OH ratio >1, esp. 2-10, and using di- or polyamines as chain-extenders. Up to 50 vol. % fillers can be added, e.g. silicates, fibres, soaps, plant nutrients, salts, fertilisers, or aq. solns. of other natural or synthetic polymers. The gels are useful for prodn. of cushioning elements, shock-absorbers, fire-resistive coatings, flame-proof insulators, binders for solid and fibrous fillers, substrates for plant-nutrients. Gels are highly stable. Dispersant, i.e. water or alcohol, is strongly bonded in gel, and does not escape by evaporation or diffusion. |