Cellular polymer containing perforated cell windows and a process for the preparation thereof
AssigneeThe Dow Chemical Company
InventorsGuido F. Smits, Johan A. Thoen
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Abstract
A process for preparing a cellular polymer containing perforated cell windows in the presence of a perforating agent being a substance that has a critical surface free energy of less than about 23 mJ/m.sup.2 is disclosed. The cellular polymers obtained according to this invention have a fine cell structure and show enhanced dimensional and thermal insulation stability. The invention also relates to rigid polyurethane foam prepared in the presence of, for example, particulate poly(tetrafluoroethylene) or a liquid polyfluoro- or perfluorocarbon, with a boiling point of at least 130.degree. C., as perforating agent.
Claims8
A process for preparing a cellular polymer containing perforated cell windows wherein the polymer is prepared in the presence of perforating agent characterized in that the perforating agent, present in from about 0.01 to about 1.0 percent based on total weight of polymer, is a polyfluorinated liquid having an average molecular weight of at lest 350 and a boiling point at a temperature of at least 130.degree. C., which temperature is greater than the maximum temperature encountered in the process of preparing the polymer.
Dependencies are inferred from the claim text.