Foaming system for closed-cell rigid polymer foam
AssigneeThe Dow Chemical Company
InventorsGuido F. Smits, Johan A. Thoen
Life of this patent
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Abstract
This invention relates to the use of a C.sub.2-6 polyfluorocarbon compound containing no chlorine or bromine atoms as physical blowing agent in the preparation of rigid, closed-cell, polymer foams. Use of such blowing agents, especially 1,1,1,2-tetrafluoroethane (R-134a), in the preparation of polyurethane or polyisocyanurate foams provided for products in which the loss in thermal insulation performance with time compared to products prepared in absence of such blowing agents is reduced.
Claims15
A closed-cell rigid polymer foam prepared from a foam-forming composition containing a physical blowing agent present in up to about 20 weight percent based on the total weight of the composition, and characterized in that the physical blowing agent comprises a C.sub.2-6 polyfluorocarbon compound containing no chlorine or bromine atoms, and in that the cells of the foam contain the physical blowing agent as a gas in an amount which reduces the thermal insulation loss of the foam relative to the thermal insulation loss, with time, of the same foam having the same density and prepared from the same foam-forming composition in the presence of an equivalent molar quantity of a blowing agent in which a C.sub.2-6 polyfluorocarbon compound containing no chlorine or bromine atoms is present.
A process for producing a closed-cell rigid polyurethane or polyisocyanurate polymer foam containing within its cells a gas mixture comprising a C.sub.2-6 polyfluorocarbon compound containing no chlorine or bromine atoms characterized in that
- (a) an isocyanate-containing compound is
- mixed and allowed to react with an active
- hydrogen-containing compound in the presence
- of up to about 20 weight percent, based on combined weight of isocyanate-containing compound and active hydrogen-containing compound, of a physical blowing agent comprising the polyfluorocarbon compound, and
- (b) the cells of the resulting foam comprise the polyfluorocarbon compound in an amount which reduces the thermal insulation loss of the foam relative to the thermal insulation loss, with time, the same foam having the same density and prepared from the same foam-forming composition in the presence of an equivalent molar quantity of a blowing agent in which a C.sub.2-6 polyfluorocarbon compound containing no chlorine or bromine atoms is absent.
An active hydrogen-containing composition suitable for reacting with an isocyanate-containing compound in the preparation of a closed-cell rigid polyurethane or polyisocyanurate foam characterized in that the composition comprises
- (a) an active hydrogen-containing compound having at least 2 active hydrogen atoms per molecule and having an equivalent weight of from about 50 to about 700, and
- (b) from about 1 to about 20 weight percent based on a combined weight of (a) and (b) present of a physical blowing agent comprising a C.sub.2-6 polyfluorocarbon compound containing no chlorine or bromine atoms, which provides for a foam wherein the thermal insulation loss of the foam relative to the thermal insulation loss, with time, the same foam having the same density and prepared from the same active hydrogen-containing composition in the presence of an equivalent molar quantity of a physical blowing agent not comprising a C.sub.2-6 polyfluorocarbon compound that contains no chlorine or bromine.
Dependencies are inferred from the claim text.