Sheet in PFA HCR AB 3000x1500x2.8 mm natural

A sheet in PFA HCR AB differs from ordinary PFA in two ways. HCR stands for cross-linked PFA, which means the polymer chains are chemically linked. That raises mechanical toughness, crack resistance and creep stiffness compared with thermoplastic PFA. AB marks the antistatic modification, an additive that leads static charge away from the surface so charge build-up does not become a risk in the process.

The combination is made for demanding processes where neither static build-up nor chemical attack can be accepted. The PFA base gives the material broad chemical resistance against acids, bases, solvents and oxidizing media; even strong aggressive media such as sulfuric acid, nitric acid and sodium hydroxide leave the material alone at normal concentrations. The service temperature is high; PFA handles continuous duty around 260 degrees and short peaks around 300 degrees. The cross-linking lifts the long term dimensional stability, so the sheet creeps less under load and takes mechanical load over time better than pure thermoplastic PFA. That shows clearly in static seals and load bearing functions where bolt pressure or media pressure acts constantly.

The antistatic additive gives the surface a controlled conductivity. It means charge does not build up on the sheet, which is critical in the semiconductor industry, electronics production, solvent handling and powder handling where a spark can ignite a vapor phase or damage components. The surface resistance sits in the range classed as static dissipative, so the sheet can be used both as a process component and as a floor element in an ESD sensitive environment.

The material is used for things like:

Lining layers in tanks and reactors where static build-up is a risk

Slide layers and support plates in cleanroom environments

Components in liquid handling systems for aggressive chemistry in the semiconductor industry

Seals and gaskets where thermoplastic PFA does not have the creep stiffness needed

Bearing and sliding surfaces in process equipment where friction, chemistry and ESD work together

Plates in equipment for organic solvents with a risk of ignition

Water uptake is negligible, which means the sheet holds its dimensions even in a damp or condensing environment. The surface is smooth, has low friction and is very nearly non-stick, so the process medium does not take hold and cleaning goes quickly. The antistatic modification runs through the material, which means grinding, milling and cutting do not remove the property; the surface is conductive after machining as well.

Machining differs from ordinary thermoplastic PFA. Since HCR is cross-linked, the sheet cannot be thermally welded or melt formed and has to be machined instead. Cut and mill with sharp carbide tools and a moderate feed. The material is tough and takes machining well, but gives a fluffy edge if the tools are dull. Use dry machining or air cooling; water based cooling can introduce contaminants in the surface that affect both the ESD properties and the process cleanliness. Through bolts with spacer washers work better than threads cut directly in the material, since PFA is fairly soft under point load.

Choosing thickness, you govern both the stiffness of the sheet and its ability to take mechanical load without deforming. Thicker gives dimensional stability in load bearing functions, thinner is enough when the role is a lining layer or a release surface. Thickness does not affect the ESD properties noticeably; the conductivity is evenly spread through the whole cross section.

Do you want to compare PFA HCR AB against pure PFA or a conductive version for your specific application? Get in touch and we will go through chemistry, ESD requirements and mechanical load together.

The sheet measures 3000x1500x2.8 mm and is the flat counterpart for anyone who would rather line wall by wall than roll out. Here too HCR stands for extra corrosion resistance, meant for the most aggressive baths. The aramid fabric on the back makes it possible to laminate the sheet in place where pure fluoroplastic would not stick.