Syntactic in-situ foam, for packaging, cavity filling, etc. - consists of polystyrene or other foam particles bonded in a matrix of isocyanate prepolymer and activated with water to give compact foam

摘要

Syntactic in-situ foam (I) comprises foam particles (A) bonded with a matrix (B) to form a compact foam. (A) Pref. consists of spherical prefoamed polystyrene, polyolefin or other material, or shredded scrap. This is predried, wetted with matrix (B) (pref. a hydrophilic TDI prepolymer), and activated with water, with wt. ratio (A):(B):(water) = approx. 100:100:100. USE/ADVANTAGE - (I) is superior to prior art rigid polystyrene foam in the following respects: high flexibility and elasticity, variable air permeability at densities 40-100 kg/m3 and water-tightness from 100 kg/m3 upwards, high sound and shock absorption, mobile cavity filling, largely pressureless mouldability, good adhesive bonding with cover sheets at the prodn. stage, simple recycling by shredding without chemical or thermal treatment, simple processing and application. (I) is therefore useful for packaging applications, flexible elastic sheets and mouldings, light-wt. orthopaedic parts, protectors, cavity fillings with a moulded skin (surfboards, parts for aircraft, boats and models), insulating or supporting foam for roofing, etc., and foam for sticking to moist substrates.