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Materials Used - PTFE

Our core expertise, and much of the work we do, involves processing of corrosion resistant and high purity fluoropolymers such as PTFE, PFA, FEP, PCTFE and PVDF.

The fluoropolymers industry had its beginnings with PTFE (formerly referred to as TFE) which stands for Polytetrafluoroethylene, the polymer discovered by DuPont in 1938. Since then, other manufacturers entered the market and produce the material under their own trade names. A broad overview of the material can be found in the on-line encyclopedia Wikipedia here.

More specific sources of information come from the manufacturers themselves, including:

3M, who manufactures PTFE under the trade name Dyneon™
DuPont, who manufactures PTFE under the trade name Teflon®
Daikin America, who manufactures PTFE under the trade name DAIKIN-POLYFLON™
AGC Chemicals America, who manufacturers PTFE under the trade name Fluon®

Each manufacturer offers PTFE in a variety of formulations generally referred to as "compounds", differing mostly in the size of the raw powdered resin particles and various added fillers. Fillers can be materials such as carbon to increase electrical conductivity (making parts static dissipative) and glass fibers to enhance certain mechanical properties. Of course, there are always trade-offs to consider in that fillers may adversely affect some material properties. Micromold's years of experience can help you intelligently select the best compound for your particular application.

Since PTFE will not flow above its melting point, it cannot be injection molded and requires special processing techniques. Molded PTFE is processed by first compression molding the powder into preforms, and then sintering the preforms in a process analogous to sintered metal processing. This process creates geometric shapes that can then be machined, fused, and/or welded.

PTFE Y-Strainer cross-sectional view
In this product, the three large outer PTFE body parts and two end connection bosses are fillet welded using PFA welding rod. The sealing o-rings are FEP encapsulated and the PTFE inner and outer cartridge cages are snap-fit into the threaded PTFE removable knob. The standard strainer mesh is another fluoropolymer, Tefzel® ETFE. Combining all these materials results in a corrosion resistant assembly where all wetted surfaces are fluoropolymers of one form or another. It can withstand continuous service with hot 98% sulfuric acid, for instance—an environment that would rapidly destroy most metals.

Micromold processes all the material used in-house except the o-rings and mesh.

PTFE Lined & Jacketed Dip Pipes and PTFE Nozzle Liners
Consider the reaction vessel accessories depicted in the figure to the left. These dip pipes and nozzle liners share at least one feature in common. In both cases, Micromold processes the raw PTFE from powder from molding through machining to create the flanges and then fuses the flanges to extruded PTFE tube. Fusion is done using dedicated equipment developed at Micromold to combine carefully calibrated heat and pressure. The proprietary fusion process causes the parts to merge, essentially creating a single seamless product. The same chemical inertness of PTFE that makes it a good choice in corrosive chemical environments makes it difficult to join it to itself and other materials. Thus, fusing and welding using other fluoropolymers as the intermediaries are used extensively in our shop. PFA and FEP can both be used to weld PTFE.

Trademark Attribution DuPont™, Delrin®, Vespel®, Tefzel® and Teflon® are trademarks or registered trademarks of E. I. du Pont de Nemours and Company or its affiliates. Dyneon™ is a trademark of the 3M Company. DAIKIN-POLYFLON™ is a trademark of Daikin America Inc. Fluon® is a registered trademark of AGC Chemicals America. Kynar® is a registered trademark of Arkema Inc. Hylar®, Solef® and Torlon® are registered trademarks of Solvay Solexis. Celcon® is a registered trademark of Ticona Engineering Polymers. Ryton® is a registered trademark of Chevron Phillips Chemical Celazole® is a registered trademark of Quadrant Engineering Plastic Products