<VV> Viton...

[Secular]

  The story began in April 1954, when Dr. Dean R. Rexford of the 
  DuPont Organics Chemicals Department in Wilmington, Delaware, USA, 
  was experimenting with a new elastomer with high temperature and 
  chemical resistance. 

  Unfortunately, there was one major barrier. Commercial scale 
  polymerization of the materials used to make this product was 
  considered a significant potential safety risk. It was up to 
  Dr. Rexford, chemist and inventor, to tackle this issue. 

  Following a controlled reaction involving hexafluoropropene, vinylidene 
  fluoride and polymerization initiators, an elastic 60/40 HFP/VF2 copolymer 
  was obtained. Its elastomeric properties were sufficiently exciting for 
  the company to file U.S. Patent Application No. 504,351 on April 27, 1954, 
  to protect the discovery. Corresponding U.S. Patent No. 3,051,677 was 
  issued on August 28, 1962...

  source:
  http://news.thomasnet.com/companystory/808724


  Tony I.