Heat aged perfluoropolymer

Abstract

Tensile strength after heat aged of articles molded from melt-fabricable perfluoropolymer is improved by incorporating polytetrafluoroethylene as dispersed submicrometer-size particles into the melt-fabricable perfluoropolymer.

1 . In the process of melt-fabricating an article from melt-fabricable perfluoropolymer and exposing said article to elevated temperature sufficient to cause deterioration of tensile strength, the improvement comprising carrying out said melt-fabricating with said melt-fabricable perfluoropolymer containing submicrometer-size particles of non-melt flowable polytetrafluoroethylene dispersed therein in an effective amount to reduce said deterioration of tensile strength. 
     
     
         2 . In the process of  claim 1  wherein said article is sheet-like. 
     
     
         3 . In the process of  claim 2  wherein said sheet-like article is an extruded sheet. 
     
     
         4 . In the process of  claim 2  wherein said article is extruded and has an annular cross-section. 
     
     
         5 . In the process of  claim 1  wherein said particles of non-melt flowable polytetrafluoroethylene comprise about 4 to 40 wt % of the combined weight of said particles of non-melt flowable polytetrafluoroethylene and said melt-fabricable perfluoropolymer.