Stabilizer for polymer polyol production processes

A process for producing a polymer polyol dispersion by melt emulsification, the process comprising:

• physically mixing a polymer melt and a polyol in the presence of a stabilizer (S),
• wherein the stabilizer (S) comprises, based on the total weight of the stabilizer (S):
• from 10 to 59 wt % of a polyether polyol P2 having a number average molecular weight, Mn, of 1,000-6,000 g/mol;
• and
• a polyol CSP consisting of, in reacted form, a macromere M, styrene, acrylonitrile, optionally an initiator, and optionally a chain transfer agent, wherein the macromere M, styrene, acrylonitrile, optional initiator, and optional chain transfer agent are reacted in the presence of the polyol P2, to obtain the polyol CSP,
• wherein the content of macromere M in the stabilizer (S) is between 35 to 54 wt %, based on the total weight of the stabilizer (S),
• wherein the content of styrene in the stabilizer (S) is between 4 to 15 wt %, based on the total weight of the stabilizer (S),
• wherein the content of acrylonitrile in the stabilizer (S) is between 2 to 7 wt %, based on the total weight of the stabilizer (S),
• wherein the macromere M is obtained by reacting 1,1-dimethyl meta isopropenyl benzyl isocyanate (TMI) with a polyether polyol PM, optionally in the presence of a Lewis acid catalyst, and
• wherein the stabilizer (S) comprises no additional solvent.