High viscosity surfactants for the manufacture of polyurethane foams

A method of manufacturing polyurethane foam comprising:

• 1) preparing a mixture comprising:
• (a) a siloxane-oxyalkylene copolymer having the general formula M"D.sub.x D".sub.y M" wherein:
• M" represents (CH.sub.3).sub.3 SiO.sub.1/2 or R(CH.sub.3).sub.2 SiO.sub.1/2 ;
• D represents (CH.sub.3).sub.2 SiO.sub.2/2 ;
• D" represents (CH.sub.3)(R)SiO.sub.2/2 ;
• x is 81-220, y is 8-40, and x/y<10;
• R is a polyether-containing substituent derived from a blend of C.sub.n H.sub.2n -started polyethers selected from the following two groups such that the overall average molecular mass of the polyethers in the surfactant are in the range 1100-1800:
• (i) --C.sub.n H.sub.2n O(C.sub.2 H.sub.4 O).sub.a (C.sub.3 H.sub.6 O).sub.b R" moieties having a blend average molecular mass in the range 2000-6000, and wherein:
• at least one polyether of type (i) has a molecular weight above 3000;
• n is 3-10:
• a is a number such that ethylene oxide residues constitute greater than or equal to 30%, but less than or equal to 50%, by weight of the alkylene oxide residues of the polyether;
• b is a number such that propylene oxide residues constitute less than or equal to 70%, but greater than 50% by weight, of the alkylene oxide residues of the polyether;
• R" represents --H, an alkyl group of 1-4 carbon atoms, --C(O)R'", --C(O)OR'" or --C(O)NHR'";
• and
• R'" represents mono-functional alkyl or aryl groups;
• and
• (ii) --C.sub.n H.sub.2n O(C.sub.2 H.sub.4 O).sub.a '(C.sub.3 H.sub.6 O).sub.b 'R" moieties having average molecular masses in the range 300-750, and wherein:
• n' is 3-10:
• a' is 30 to a number such that ethylene oxide residues constitute 30% to 100% by weight of the alkylene oxide residues of the polyether;
• and
• b' is 0 to a number such that propylene oxide residues constitute less than or equal to 70% by weight of the alkylene oxide residues of the polyether;
• and
• R" is as defined above;
• and
• (b) a diluent in an amount sufficient to reduce the viscosity of the mixture to less than 3,000 cP;
• 2) preparing a mixture comprising:
• (a) a polyether polyol containing an average of more than two hydroxyl groups per molecule:
• (b) an organic diisocyanate;
• (c) at least one catalyst for production of polyurethane foam;
• (d) water;
• (e) the mixture made in step (1);
• and
• (f) optionally, reduced or no blowing agent;
• 2) allowing the mixture made in step (2) to foam;
• and
• 3) curing the foamed composition.