ALEXANDRIA, Va., March 26 -- United States Patent no. 12,258,436, issued on March 25, was assigned to REPSOL, S.A (Madrid).
"Method for the preparation of polymer polyols" was invented by Juan Pedro Perez Valencia (Madrid), Jose Antonio Carazo Angulo (Madrid) and Felix Fernandez Villar (Madrid).
According to the abstract* released by the U.S. Patent & Trademark Office: "The present invention refers to the use of hydrofoil impellers for the preparation of polymer polyols and to a method for preparing a polymer polyol, which comprises reacting a base polyol, at least one ethylenically unsaturated monomer and a macromer or a preformed stabilizer in the presence of a free-radical initiator and optionally a chain transfer agent in a reactor, w...