Flexible polyurethane foams from polymethylene polyphenyl isocyanate containing prepolymers
AssigneeW. R. Grace & Co.
InventorsRobert M. Murch, Louis L. Wood
Life of this patent
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Abstract
Flexible polyurethane foams are made from isocyanate containing prepolymers where the isocyanate is a mixture of diphenylmethane diisocyanate (MDI) and polymeric forms of MDI. The isocyanate mixture has a functionality greater than 2.0. The prepolymer is an isocyanate capped polyol or mixture of polyols where the polyols are diols or triols having at least 50% by weight oxyethylene groups. The foams are made by reacting water with the prepolymer and fire retardant materials can be added to the reaction mixture to produce fire retardant foams. The foams have improved physical properties and flammability resistance.
Claims25
A flexible foam having low compression set values of about 25% or less and good hydrolytic stability made by mixing together and reacting an aqueous phase and
- a resin phase comprising a prepolymer derived from
- (a) a diphenylmethane diisocyanate-containing isocyanate product with a functionality of greater than 2.0 comprising a mixture of diphenylmethane diisocyanate and polymethylene polyphenyl isocyanate, and
- (b) a polyol having at least about 50% by weight of oxyethylene groups and having nominally two to three hydroxyl equivalents per mole,
- the ratio of the isocyanate equivalents to the total hydroxyl equivalents being in the range of 1.5:1 to 5:1.
A prepolymer capable of reacting with water to form a flexible foam having low compression set values and good hydrolytic stability, said prepolymer made by reacting together
- (a) a diphenylmethane diisocyanate-containing isocyanate product with a functionality of greater than 2.0 comprising a mixture of diphenylmethane diisocyanate and polymethylene polyphenyl isocyanate, and
- (b) a polyol having at least about 50% by weight of oxyethylene groups and having nominally two to three hydroxyl equivalents per mole,
- the ratio of the isocyanate equivalents to the total hydroxyl equivalents being in the range of 1.5:1 to 5:1.
A method of making a flexible foam having low compression set values of about 25% or less and good hydrolytic stability comprising mixing together and reacting an aqueous phase and
- a resin phase comprising a prepolymer derived from
- (a) a diphenylmethane diisocyanate-containing isocyanate product with a functionality of greater than 2.0 comprising a mixture of diphenylmethane diisocyanate and polymethylene polyphenyl isocyanate, and
- (b) a polyol having at least about 50% by weight of oxyethylene groups and having nominally two to three hydroxyl equivalents per mole,
- the ratio of the isocyanate equivalents to the total hydroxyl equivalents being in the range of 1.5:1 to 5:1.
Dependencies are inferred from the claim text.