Patent Title: PROCESS MAKING POLYMER POLYOL HAVING MONODISPERSE DISPERSED POLYMER PARTICLES

 Number/Link: WO2017/172417

Applicant/Assignee:  Dow

Publication date: 5 october 2017

“Gist”: Polymer polyol with a “monodisperse” particle size distribution is prepared by using a specific seeding dispersion

Why it is interesting: It is well known that the use of polymer polyols in flexible polyurethane foam formulations can result in improved airflow and load bearing properties. For optimal results the average particle size of the dispersed polymer needs to be similar to the cell wall thickness. According to this invention a SAN polymer polyol with a controlled and narrow particle size distribution can be prepared by using a seed dispersion which consists of an unsaturated macromer which, together with SAN particles of a particle size between 50 and 500 nm, is dispersed in a base polyol. The macromer is a PO/EO polyether with a (pref.) mole weight of 11000 to 14000 Da and having 4-5 OH groups and 1-2 reactive double bonds. The polymer polyol is prepared by dispersing the seed dispersion in the base polyol together with styrene, acrylonitrile and a solvent (e.g. isopropanol). After polymerization of the monomers the solvent is removed, resulting in a polymer polyol with at least 30% solids, average particle size of 1-3 μm and a size span of 1.25. In the examples the macromer is prepared by capping 1-2 OH groups of a 6-functional 90/10 PO/EO polyol with 3,3-isoprenyl-α,α-dimethylbenzylisocyanate.

3,3-isoprenyl-α,α-dimethylbenzylisocyanate