WEAKLY MODIFIED PREPOLYMERS AND USE THEREOF Russian patent published in 2016 - IPC C08G18/10 C08G18/42 C08G18/40 C08G18/80 C08G18/76 

FIELD: chemistry.

SUBSTANCE: invention describes a prepolymer C with terminal isocyanate groups with content of NCO-groups from ≥ 26.0 wt% to ≤ 31.0 wt% based on weight of prepolymer obtained from reaction of (i) an isocyanate composition A having viscosity at 25 °C from ≥ 90 mPa·s to ≤ 300 mPa·s, including ≥ 25 wt% to ≤ 60 wt% of monomeric diphenylmethane diisocyanate A1 and from ≥ 40 wt% to ≤ 75 wt% of polymeric diphenylmethane diisocyanate A2, wherein sum of proportions of components A1 and A2 is ≤ 100 wt%, with (ii) polyester polyol B with ether and ester groups with average functionality of ≥ 1.9 to ≤ 2.1 and OH-number from ≥ 200 mg(KOH)/g to ≤ 500 mg(KOH)/g, obtained from reaction of an organic dicarboxylic acid or, respectively, its anhydride having number of carbon atoms from 4 to 6 B1 with at least one diol having number of carbon atoms from 2 to 6 B2, and alkyleneoxide B3, wherein said polyesterpolyol B with ether and ester groups and is used in amounts of ≥ 1.5 wt% to ≤ 6.0 wt% based on sum weight of A and B. Also described is polyurethane/polyisocyanurate polymer and a composite element comprising polyurethane/polyisocyanurate polymer and a steel coating layer.

EFFECT: technical result is obtaining NCO-prepolymers, which have very good adhesion to metal coating layers in metal-composite elements.

11 cl, 3 ex, 1 tbl