Liquid compsn. contg. silica sol. and thermosetting resin - esp. urea-formaldehyde resin, as binder, coating compsn. and adhesive

摘要

A liq. compsn. contains (a) 5-50(10-35)wt.% of a SiO2, sol, and (b) balance of an aq. soln. of a heat-hardening resin. The resin is pref. a urea-HCHO resin. The resin soln. may be mixed directly with the sol, or with an aq. soln. of an alkali silicate, followed by acidification. The compsns. are used as binders for particles and fibres, e.g. glass or asbestos fibres or paper, or as coatings and adhesives. They can be cast or moulded into blocks, panels or tiles. Sealants, mortars and grouts can be obtd. by mixing with aggregates, e.g. sand, clay, gypsum of plaster. The compsn. can be used as an aq. resin, and dried an and hardened with acid catalysts to thick, water-resistant articles, which have less tendency to crack. The compsns. bond to surfaces for which urea-HCHO resins are not suitable. When used as an adhesive, pref. is not 1 of the surfaces to be bonded is water-absorbent; better bonding is obtd. than with known compsns.