Chemically-resistant crack-bridging coating system for concrete etc. - comprises reinforced epoxy] or polyurethane impregnating layer, and base-coat and top-coat contg. epoxy] resin and thiol-terminated oligomer

摘要

The coating system (I) comprises (i) impregnation of the substrate with epoxy- or polyurethane resin (PUR) (II), (ii) a reinforcing interlayer(s), (iii) basecoat and (iv) topcoat. The binder in (iii) is a combination of epoxy resin, PUR prepolymer and liq. oligomer with mercapto end gps. (III), and the binder in (iv) is flexibilised epoxy resin (IV). Wt. ratio (epoxy resin),:(PUR prepolymer):(IV) in basecoat (iii) = 3:1(1-10):(1-9). The binder in (iv) is an epoxy resin flexibilised with (IV), pref. an oligomer of mol. wt. 1000-4000 with formula HS-(RSS)x-RSH (with x = 5-23; R = a gp. of formula -C2H4-OCH2-O-C2H4-). USE/ADVANTAGE - Used for coating tank spill troughs, bridge and multi-story car park structures, and industrial floors (claimed). The invention provides a coating system esp. for concrete structures, which is able effectively to bridge cracks of at least 0.2mm both at +20 deg.C and -20 deg.C.