Since P-99 is now discontinued and no longer being made by Permacel (we currently only have some 1/2" wide stock remaining) we keep on getting asked for a suitable replacement tape. Primarily since Permacel P-99 was written into the ASTM D3359-09 measuring adhesion by tape test standard. 3M 720 is a tape of similar construction (polyester film/paper fiber carrier with a rubber adhesive); however 720 is not specifically written into the test standard and it is also now discontinued. We contacted ASTM about the situation and they said they have not recommended a substitute tape yet, but they said they would be discussing replacement tapes at their next meeting in January. If any recommendations come out of that meeting we will follow-up here.
UPDATE (2/14/2010): The last update we received from the ASTM D01.23 subcommittee was that D3359 has not been revised yet and that the committee needs to complete a round robin. Comparative tests are being planned on 3 tapes: Intertape LA-26, Scapa 8010B and CHT-1. A round robin will result from the tests and then D3359 will be updated afterwards.