Process for extending the shelf life of gaseous olefinic propellants in polyurethane foams
View Patent ↗The invention described herein generally pertains to a composition and a method for improving the shelf life of a gaseous hydrofluoroolefin propellant, the improvement comprising at least the increased aromatic polyester polyol(s) in combination with a tertiary amine catalyst comprising at least two cyclohexyl rings and an aliphatic metal salt catalyst, the amine catalyst having less than 10% nitrogen on a weight basis.
1. A two-component polyurethane foam comprising a reaction product of:
an “A-side” diisocyanate with an HFO-1234ze propellant; and
a “B-side” blend with an HFO-1234ze propellant;
the polyurethane foam reaction product comprising:
at least two aromatic polyester polyols and no more than approximately 10 wt. % aliphatic polyether polyol,
and wherein the at least two aromatic polyester polyols comprise:
having a viscosity at 77° F. (25° C.), of between approximately 2,000-4,500 cP; and
n being a value sufficient to achieve the viscosity; and
having a viscosity at 77° F. (25° C.) of between approximately 2,500-3,500 cP; and
n being a value sufficient to achieve the viscosity;
at least two catalysts comprising:
at least one tertiary amine catalyst comprising at least two cyclohexyl rings;
at least one aliphatic metal salt catalyst; and
up to about 1.5 wt. % water.
2. The polyurethane foam of claim 1 which further comprises
no more than ˜1 wt. % of an aliphatic polyether polyol.
3. The polyurethane foam of claim 1 comprising:
essentially no added water.
4. The polyurethane foam of claim 1 in which at least one of the at least two aromatic polyester polyols comprises:
at least two aromatic rings.
5. The polyurethane foam of claim 1 wherein
the at least one tertiary amine catalyst comprises no more than 11 wt. % nitrogen.
6. The polyurethane foam of claim 5 wherein
the at least one tertiary amine catalyst comprises no more than 10 wt. % nitrogen.
7. The polyurethane foam of claim 1 wherein
the aliphatic metal salt is a metal alkanoate.
8. The polyurethane foam of claim 7 wherein
the metal alkanoate is a potassium alkanoate.
9. The polyurethane foam of claim 8 wherein
the potassium alkanoate is potassium octoate.
10. The polyurethane foam of claim 1 which further comprises:
a halogenated plasticizer.
11. The polyurethane foam of claim 10 which further comprises:
a brominated phthalate diol flame retardant.
12. The polyurethane foam of claim 11 which further comprises:
at least one surfactant.
13. The polyurethane foam of claim 12 in which the “A-side” and “B-side” further comprise:
an inert pressurizing gas.