15/6/2021 · HS Code. 8421999090. Product Description. FDA Standard PTFE Filter Membrane for Sterile Filtration 0.22 Micron SGS Test. PTFE Filter Membrane (TF, NF, CF, WF) TF Series has hydrophilic membrane and hydrophobic membrane. Permanent hydrophilic membrane is mainly applied in clarification, absolute steam filtration and sewage treatment.