HARD POLYURETHANE WITH LOW DENSITY, EXPOSED ONLY UNDER THE ACTION OF WATER Russian patent published in 2017 - IPC C08G18/10 C08G18/28 C08G18/40 C08G18/48 C08G18/65 C08G18/66 C08G101/00 

FIELD: chemistry.

SUBSTANCE: composition comprises an isocyanate component, an isocyanate-reactive component, from 1.5 to 5 wt % of the catalyst, from 0 to 1 wt % of a trimerization catalyst, more than 4.1 wt % of water serving as a foaming agent, and any additional components. The isocyanate-reactive component comprises 30 to 50 wt % of a first polyether polyol having a functionality greater than 5 and a hydroxyl value in the range of 350-550 mg KOH/g, 5 to 25 wt % of at least one diol, characterized by a hydroxyl value in the range of 100-300 mg KOH/g and 15 to 35 wt % of a second polyether polyol having a functionality in the range of 3-5. The catalyst is selected from dimethylbenzylamine, 1,2-dimethylimidazole or combinations thereof. The trimerization catalyst is selected from the glycine salt, tris (dimethylaminomethyl) phenol, or combinations thereof. The composition in the absence of isocyanate is characterized by the value of dynamic viscosity in the range of 540-864 mPa⋅S at 20°C. Processing under conditions of a single-step regime leads to the formation of a rigid polyurethane foam characterized by a ratio of the molecular weight to the cross-link in the range 380-420.

EFFECT: use of this composition makes it possible to produce low density polyurethane foams that are capable of being foamed only by the action of water, while exhibiting good processing ability and good mechanical properties, including dimensional stability.

9 cl, 2 tbl, 2 ex