Abstract: The invention relates to graft polyols with a bimodal particle size distribution and a total solid content of between 5 and 65 wt. %. Said polyols contain small particles with a particle diameter of between 0.05 and 0.7 ?m and large particles with a particle diameter of between 0.4 and 5.0 ?m, whereby the peaks of the large and small particles measured during a representation according to the light-scattering analysis method do not overlap. The total solid content with the defined particle sizes consists of a volumetric fraction of between 5 and 45% small particles and a volumetric fraction of between 95 and 55% large particles, said volumetric fractions totalling 100%. The invention also relates to a method for producing graft polyols of this type and to the use thereof for producing polyurethanes.

Abstract: The invention relates to a process for preparing mixtures of polyols for further processing to give polyurethanes, comprising at least one graft polyol, which comprises carrying out the mixing of the polyols between the preparation of the polyols and the preparation of the polyurethanes, by means of a continuous mixing process.

Abstract: The invention relates to graft polyols with a bimodal particle size distribution and a total solid content of between 5 and 65 wt. %. Said polyols contain small particles with a particle diameter of between 0.05 and 0.7 ?m and large particles with a particle diameter of between 0.4 and 5.0 ?m, whereby the peaks of the large and small particles measured during a representation according to the light-scattering analysis method do not overlap. The total solid content with the defined particle sizes consists of a volumetric fraction of between 5 and 45% small particles and a volumetric fraction of between 95 and 55% large particles, said volumetric fractions totalling 100%. The invention also relates to a method for producing graft polyols of this type and to the use thereof for producing polyurethanes.

Abstract: A process for the production of cellular polyurethanes by reactinga) at least one organic and/or modified organic polyisocyanate,b) at least one relatively high-molecular-weight compound containing at least two reactive hydrogen atoms, if desiredc) low-molecular-weight chain extenders and/or crosslinking agents,in the presence ofd) blowing agents,e) catalysts, and, if desired,f) auxiliaries and/or additives,wherein the blowing agent d) is at least one acetal.