FLUOROPOLYMERS RESISTANT TO STRESS CRACKING

摘要

The invention provides a fluorothermoplastic composition comprising interpolymerized units derived from about 94 to about 97.5 mole percent (mol%) tetrafluoroethylene (TFE), about 2 to about 3 mol% perfluoro (propyl vinyl ether) (PPVE), and about 0.5 to about 3 mol% hexafluoropropylene (HFP). The invention also provides a fluorothermoplastic composition comprising interpolymerized units derived from about 94 to about 97 mol% TFE, about 0.75 to about 3 mol% PPVE, and about 1.5 to about 3.5 mol% HFP. These fluorothermoplastic compositions have a flex life that fits the equation: log(flex life cycles) ≥ 0.71 + 4.0 * (MFI <(-0.294)>). The invention also provides a method of making fluorothermoplastic compositions and a method of improving stress crack resistance. The invention also provides fluorothermoplastic articles.