Delrin® AF Blend (Delrin® AF Blend with13% PTFE [Standard Grade] ) Delrin AF Blend is a unique thermoplastic material for use in moving parts in which low friction and long wear life are important. It is a combination of PTFE fibers uniformly dispersed in Delrin® acetal resin. Delrin® AF Blend typically includes 13% PTFE Fibre-Filled LF-13 is always a 13% PTFE Powder-Filled. Also available in Full-Strength Delrin 100AF – 20% PTFE on a Custom Order Basis. DE588 is a Delrin® 100AF fully-certified for US Naval Specifications.