Bayer Aktiengesellschaft

Bayer Adtiengesellschaft

Mark R Kratz

Manfred Dietrich

Josef Sanders

Gundolf Jacobs

Helmut Woynar

Torsten Heinemann

Uwe Scholz

Hans-Joachim Scholl

A process is described for the preparation of stable, agglomerate-free, low-viscosity graft copolymer dispersions by the free-radical polymerization of olefinic monomers, such as styrene and/or acrylonitrile, with polyol compounds in the presence of a hydroxyl compound modified with castor oil. The use of these graft copolymer dispersions in the manufacture of polyurethane plastics, particularly flexible foams, by the isocyanate polyaddition process is also described.

Polymerizing monomers in presence of polyol and castor oil-polyol product

A continuous process for the preparation of highly stable, finely divided, low viscosity polymer polyols of small average particle size wherein in the first step an intermediate is prepared by reacting (1) a mixture of at least two ethylenically unsaturated monomers, preferably styrene and acrylonitrile, in a mixture comprising (2) a base polyol and (3) a macromer in the presence of (4) a free radical initiator, (5) a solvent having moderate chain transfer activity, and, optionally, (6) a reaction moderator at a temperature of at least 100.degree. C., such that the intermediate contains at least about 12% by weight of macromer, based on the weight of the base polyol and macromer, and a solids content of at least about 15% by weight and less than about 30% by weight, based on the weight of the base polyol, macromer and ethylenically unsaturated monomers. The intermediate, which functions as a seed for further polymerization, is then further reacted, in one or more stirred-tank reactors in series, in a mixture of at least two ethylenically unsaturated monomers, preferably styrene and acrylonitrile, in a base polyol and, optionally, a macromer, in the presence of solvent, initiator and a reaction moderator which are distributed among the remaining reactors.

Continuous process for the preparation of highly stable, finely divided,

Stable, agglomerate-free, low-viscosity graft copolymer dispersions are prepared by the radical polymerization of 25 to 65% by weight of ethylenically unsaturated monomers in the presence of a base polyol, a macromer, a low-molecular weight regulator and, optionally, an organic solvent. The dispersions of this process are suitable as a polyol component for the production of polyurethane plastics by the isocyanate addition process.

Low-viscosity, stable, agglomerate-free polymer polyols, a process for

A process for the production of stable, agglomerate-free, low viscosity graft copolymer dispersions through radical polymerization of ethylenically unsaturated monomers in the presence of a base polyol, a macromer, an enol ether of a specific formula, and optionally, an organic solvent. These enol ethers correspond to the general formula:

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Krefeld, Germany

Mark R Kratz