Use of foam materials derived from high internal phase emulsions for insulation

#This application relates to the use of microporous, open-celled polymeric foam materials as insulation materials. The application particularly relates to the use of foam materials made from high internal phase emulsions.

#The development of efficient and effective insulating materials has been the subject of substantial commercial interest. This is particularly true for materials which are thermal insulators, e.g. which reduce the rate of heat loss (or gain) of any device, construct, or container. Foams are broadly used as insulators. References describing such uses and properties of foams include Oertel, G. "Polyurethane Handbook" Hanser Publishers, Munich, 1985, and Gibson, L. J.; Ashby, M. F. "Cellular Solids. Structure and Properties" Pergamon Press, Oxford, 1988. The term "insulator" refers to any material which reduces the transfer of energy from one location to another. Such energy may be include heat, acoustic, and/or mechanical types. Heat insulation is of particular importance and relates to the thermal conductivity of the insulating medium.

#The "perfect" insulator is a vacuum. Developing and maintaining an evacuated space around the area to be insulated can, however, be impractical, particularly for larger volumes. The structural integrity required to withstand atmospheric pressure acting upon a vacuum vessel can be an issue.

#FIG. 1 of the drawings is a photomicrograph (250.times. magnification) of a cut section of a representative polymeric foam useful in the present invention made from HIPE having a 48:1 water-to-oil weight ratio and poured at 57.degree. C., and where the monomer component consisted of a 12:14:62:12 weight ratio of styrene:technical grade divinyl benzene (about 55% DVB and about 45% ethyl styrene):2-ethylhexyl acrylate:1,4-butanediol dimethacrylate, and where 5% (by weight of the oil phase) of diglycerol monooleate (DGMO) and 1% commercial Span 85 emulsifiers were used.

#FIG. 2 of the drawings is a photomicrograph (1000.times. magnification) of the foam of FIG. 1.

#FIG. 3 of the drawings is a photomicrograph (250.times. magnification) of a cut section of a representative polymeric foam useful in the present invention made from HIPE having a 140:1 water-to-oil weight ratio and poured at 37.degree. C., and where the monomer component consisted of a 20:20:60 weight ratio of styrene:technical grade divinyl benzene (about 55% DVB and about 45% ethyl styrene):2-ethylhexyl acrylate, and where 6% (by weight of the oil phase) of diglycerol monooleate (DGMO).

#I. Uses of Polymeric Foams

#A. In General

#Polymeric foams for the uses of the present invention are broadly useful as thermal insulating materials. In thermal insulation applications, these polymeric foams can be provided as relatively rigid slabs of foam for use where some rigidity is desired, as with vacuum insulation panels or with building construction insulation panels that are nailed to a support structure. For these uses, the foams would generally be provided in a fully expanded state and would comprise those formulations which yield a relatively high Tg, from about 50.degree. to about 80.degree. C. The formulation would also contain relatively higher levels of toughening monomers as described below. As rigid slabs, the foams of this invention may be laminated or bonded to other support media to provide stiffness, strength, or better insulating properties. For example, a thin sheet of reflective foil can be laminated on one or both sides of the foam slab so as to reduce further radiative heat transfer through the structure.