Open-celled rigid polyurethane foam
AssigneeThe Dow Chemical Company
InventorsGuido F. Smits, Guliano Cini, Henri J. M. Grunbauer, Jacobus A. F. Broos
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Abstract
Disclosed is a process for preparing an open-celled rigid polyurethane foam by reacting a polyisocyanate with a polyol in the presence of a blowing agent, usually water, and a cell opening agent. The cell opening agent comprises a combination of a polyoxyalkylene polysiloxane having a cloud point of 65.degree. C. or less, and a second substance that has a critical surface free energy of less than about 23 mJ/m.sup.2. Highly preferred as second substance is fine particulate poly(tetrafluoroethylene) polymer.
Claims7
A polyol composition suitable for use when preparing open-celled rigid polyurethane foam which, based on its total weight, comprises:
- a) from about 99.9 to 90 weight percent of a polyol;
- and
- b) from about 0.1 to 10 weight percent of a cell opening agent that contains a polyoxyalkylene polysiloxane (a) having a cloud point temperature of less than about 65.degree. C., and a substance (b) that has a critical surface free energy of less than about 23 mJ/m.sup.2 and, which when a solid, has an average particle size of about 20 microns or less and, when a liquid, has a boiling point greater than the maximum temperature encountered in the process of preparing the polymer, wherein (a) and (b) are present in a parts by weight ratio of from about 8:01 to about 1:8.
Dependencies are inferred from the claim text.