Catalysts for polyurethane foam polyol premixes containing halogenated olefin blowing agents

Abstract

The invention provides polyurethane and polyisocyanurate foams and methods for the preparation thereof. More particularly, the invention relates to closed-celled, polyurethane and polyisocyanurate foams and methods for their preparation. The foams are characterized by a fine uniform cell structure and little or no foam collapse. The foams are produced with a polyol premix composition which comprises a combination of a hydrohaloolefin blowing agent, a polyol, a silicone surfactant, and a non-amine catalyst used alone or in combination with an amine catalyst.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]The present application is a division of U.S. application Ser. No. 13 / 400,563, filed Feb. 20, 2012, which application relates to and claims the priority benefit of each of U.S. Application 61 / 445,027, filed Feb. 21, 2011 and U.S. Application 61 / 445,022, filed Feb. 21, 2011, each of which is incorporated herein by reference in its entirety as if fully set forth below.[0002]Also incorporated herein by reference is U.S. application Ser. No. 13 / 400,559, now U.S. Pat. No. 9,051,442.FIELD OF THE INVENTION[0003]The present invention pertains to polyurethane and polyisocyanurate foams, to blowing agents and catalyst systems and methods for the preparation thereof.BACKGROUND OF THE INVENTION[0004]Low density, rigid to semi-rigid polyurethane or polyisocyanurate foams have utility in a wide variety of insulation applications including roofing systems, building panels, building envelope insulation, spray applied foams, one and two component froth fo...

AI Technical Summary

Benefits of technology

The patent text describes a way to make polyol premixes that can be used to make foam with a long shelf life. By adding certain chemicals to the premix, the foam can be made even if it has been stored for a few weeks or months. This provides a better shelf life for the foam, even if it has been produced using a polyol blend that has been stored for a long time.

Problems solved by technology

If a surfactant is not used in the foaming composition, the bubbles simply pass through the liquid mixture without forming a foam or forming a foam with large, irregular cells rendering it not useful.

However, applicants have found that if the polyol premix composition containing a halogenated olefin blowing agent and a typical amine-containing catalyst is aged, prior to treatment with the polyisocyanate, deleterious effects can occur.

For example, applicants have found that such formulations can produce a foamable composition which has an undesirable increase in reactivity time and / or a subsequent cell coalescence.

The resulting foams are of lower quality and / or may even collapse during the formation of the foam.

It has now been found that one source of the problem observerd by applicants is the reaction of certain amine catalysts with certain hydrohaloolefins.

Although applicants do not wish to be bound by or to any particular theory, it is believed that such reactions have both direct and indirect deleterious effects.

For example, the decomposition reaction depletes the availability of the amine catalyst and hence has a negative effect on reaction times and the quality of foam.

In addition, while applicants believe that all halogenated olefin blowing agents will exhibit some level of the deleterious effects mentioned above, applicants had surprisingly and unexpectedly found that a certain halogenated olefin, particularly monochloro-trifluoropropenes and even more particularly trans-1-chloro-3,3,3-trifluoropropene (1233zd(E)), tend to exhibit only a relatively low level of the deleterious effect, especially when used in combination with catalyst which contains a relatively low level, and preferably no substantial amount of amine-containing catalyst.

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