Blowing agent composition and polymeric foam containing a normally-liquid hydrofluorocarbon and carbon dioxide

Abstract

The present invention relates to blowing agent compositions for polymeric foams that contain carbon dioxide and a hydrofluorocarbon having a boiling point of 14° C. or higher and lower than about 120° C. The present invention also relates to processes for preparing polymeric foam using such blowing agent compositions, foamable polymer compositions containing such blowing agents, and polymeric foams containing such blowing agent compositions. Suitable blowing agent combinations include: (a) a composition containing carbon dioxide and at least one hydrofluorocarbon having a boiling point of 30° C. to about 120° C. that is essentially free of other low boiling ethers and hydrocarbons; (b) a composition containing greater than 50 weight-percent carbon dioxide and at least one hydrofluorocarbon having a boiling point of 14° C. or higher to about 120° C.; and (c) carbon dioxide and one hydrofluorocarbon having a boiling point of 14° C. or higher and lower than about 120° C.

What is claimed is:  
     
         1 . A blowing agent composition comprising: 
 (a) carbon dioxide; and    (b) at least one hydrofluorocarbon having a boiling point of 30° C. or higher and lower than about 120° C.; said composition being essentially free of low-boiling ethers and low-boiling hydrocarbons other than (b).    
     
     
         2 . The blowing agent composition of  claim 1 , wherein said carbon dioxide is liquefied carbon dioxide.  
     
     
         3 . The blowing agent composition of  claim 1  wherein the hydrofluorocarbon is 1,1,1,3,3-pentafluorobutane.  
     
     
         4 . The blowing agent composition of  claim 3 , wherein the hydrofluorocarbon concentration is 30 wt % or more and 70 wt % or less based on blowing agent composition weight.  
     
     
         5 . The blowing agent composition of  claim 1 , further comprising at least one additional blowing agent selected from water and alcohols having a boiling point lower than about 120° C. at one atmosphere pressure.  
     
     
         6 . A blowing agent composition comprising: 
 (a) carbon dioxide; and    (b) at least one hydrofluorocarbon having a boiling point of 14° C. or higher and lower than about 120° C.; 
 wherein greater than 50 weight-percent of the composition is carbon dioxide and wherein a sufficient amount of (b) is present to produce a polymeric foam having an improved skin quality, lower open cell content (according to ASTM method D-6226), larger average cell size, or any combination thereof relative to the same foam prepared using only carbon dioxide as a blowing agent.  
   
     
     
         7 . The blowing agent composition of  claim 6 , wherein said carbon dioxide is liquefied carbon dioxide.  
     
     
         8 . The blowing agent composition of  claim 6 , further comprising at least one hydrofluorocarbon having a boiling point lower than 14° C.  
     
     
         9 . The blowing agent composition of  claim 6 , wherein said blowing agent composition comprises only one hydrofluorocarbon.  
     
     
         10 . The blowing agent composition of  claim 6 , further comprising at least one additional blowing agent selected from water and alcohols having a boiling point lower than about 120° C.  
     
     
         11 . The blowing agent composition of  claim 6 , that is essentially free of alcohol.  
     
     
         12 . The blowing agent composition of  claim 6 , further comprising: 
 (c) at least one hydrofluorocarbon having a boiling point lower than 14° C.; and    (d) at least one additional blowing agent selected from water, alcohols, ketones, and aldehydes; said alcohols, ketones and aldehydes having a boiling point lower than about 120° C.    
     
     
         13 . The blowing agent composition of  claim 12 , wherein (b) is 1,1,1,3,3-pentaflurobutane; (c) is 1,1,1,2-tetrafluoroethane or 1,1,1,2,3,3,3-heptafluoropropane; and (d) is ethanol.  
     
     
         14 . A blowing agent composition consisting essentially of carbon dioxide and one hydrofluorocarbon having a boiling point of 14° C. or higher and lower than about 120° C.  
     
     
         15 . A process for preparing polymeric foam comprising expanding a foamable polymer composition in a process suitable for forming a polymeric foam using a blowing agent composition selected from a group consisting of the blowing agent compositions of claims  1 ,  6 , and  14 .  
     
     
         16 . A polymeric foam comprising: 
 (a) a polymer having cells defined therein;    (b) carbon dioxide; and    (c) at least one hydrofluorocarbon having a boiling point of 30° C. or higher and lower than about 120° C.; 
 wherein at least a portion of (b) and (c) resides in said cells and said polymeric foam is essentially free of any low-boiling ethers or low-boiling hydrocarbons other than the one hydrofluorocarbon.  
   
     
     
         17 . The polymeric foam of  claim 16 , wherein the hydrofluorocarbon is 1,1,1,3,3-pentafluorobutane.  
     
     
         18 . The polymeric foam of  claim 16 , further containing an infrared blocker selected from a group consisting of carbon black, graphite, gold, aluminum, and titanium dioxide dispersed within said polymer.  
     
     
         19 . A polymeric foam comprising: 
 (a) a polymer having cells defined therein;    (b) carbon dioxide;    (c) at least one hydrofluorocarbon having a boiling point of 14° C. or higher and lower than about 120° C.;    (d) at least one hydrofluorocarbon having a boiling point lower than 14° C.;    (e) at least one additional blowing agent selected from water, alcohols, ketones, and aldehydes; said alcohols, ketones and aldehydes having a boiling point lower than about 120° C.; and    (f) an infrared blocker selected from a group consisting of carbon black, graphite, gold, aluminum, and titanium dioxide; wherein at least a portion of (b), (c), (d) and (e) reside in said cells and (f) is dispersed in said polymer.    
     
     
         20 . The polymeric foam of  claim 19 , wherein (c) is 1,1,1,3,3-pentafluorobutane.  
     
     
         21 . A foamable polymer composition comprising a thermoplastic polymer having dispersed therein a blowing agent composition selected from a group consisting of the blowing agent compositions of  claim 1 ,  claim 6 , and  claim 14 .  
     
     
         22 . A foamable polymer composition comprising a thermoplastic polymer having dispersed therein an infrared blocker and a blowing agent composition that comprises carbon dioxide and one part per hundred or more, by weight of polymer, of a hydrofluorocarbon having a boiling point of 14° C. or higher.  
     
     
         23 . The foamable polymer composition of  claim 22 , wherein said infrared blocker is selected from carbon black and graphite.  
     
     
         24 . The foamable polymer composition of  claim 22 , wherein said thermoplastic polymer is polystyrene.