Blowing agent compositions for insulating foams

Abstract

Disclosed is a blowing agent composition comprising a hydrofluoroolefins (HFO) and a branched hydrocarbon, and a foamable polymer composition comprising the blowing agent composition. Also disclosed is a method of making a polymer foam utilizing a blowing agent composition comprising an HFO and a branched hydrocarbon.

What is claimed is: 
     
         1 . A foamable polymer composition comprising:
 a matrix polymer composition comprising polystyrene; and   a blowing agent composition comprising:
 from 1 to 5 wt. % of a hydrofluoroolefin (HFO) blowing agent comprising 1,1,1,4,4,4-hexafluoro-2-butene; 
 from 0.05 to 1 wt. % of a branched hydrocarbon blowing agent; and 
 from 0.05 to 5 wt. % of a co-blowing agent comprising carbon dioxide, 
   wherein the foamable polymer composition contains essentially no water, and   wherein each wt. % is based upon the total weight of the foamable polymer composition.   
     
     
         2 . The foamable polymer composition of  claim 1 , wherein the blowing agent composition consists of the HFO blowing agent, the branched hydrocarbon blowing agent, and the carbon dioxide. 
     
     
         3 . The foamable polymer composition of  claim 1 , wherein the branched hydrocarbon blowing agent is selected from the group consisting of: isobutane; isopentane; neopentane; isohexane; 3-methylpentane; 2,3-dimethylbutane; neohexane; isoheptane; 3-methylhexane; 2,2-dimethylpentane; 2,3-dimethylpentane; 2,4-dimethylpentane; 3,3-dimethylpentane; 3-ethylpentane; 2,2,3-trimethylbutane; and combinations thereof. 
     
     
         4 . The foamable polymer composition of  claim 3 , wherein the branched hydrocarbon blowing agent consists of isobutane. 
     
     
         5 . The foamable polymer composition of  claim 1 , wherein:
 the HFO blowing agent consists of 1,1,1,4,4,4-hexafluoro-2-butene;   the branched hydrocarbon blowing agent consists of isobutane; and   the co-blowing agent consists of carbon dioxide.   
     
     
         6 . The foamable polymer composition of  claim 1 , wherein the foamable composition comprises less than 0.03 moles HFO blowing agent per 100 grams of matrix polymer.