D/W 213 is a film skived from virgin PTFE, that has been etched on one side with Sodium Naphthalene (D/W212) after which a primer has been applied to enhance bonding to elastomers and pressure sensitive adhesives. This surface treatment allows the PTFE which normally exhibits very poor adhesion to be bonded to other materials. The primer may be specified by the end user or may be recommended by DeWAL for specific applications.

The primary applications for sodium etched PTFE involve bonding to elastomers to produce laminated diaphragms, as well as the applicaton of pressure sensitive adhesives in the production of PTFE pressure sensitive tapes.