October 1, 2013
Considering a switch in order to save costs or get better functionality? Read our guide to chemical-resistant coatings to find new directions to explore.
PTFE + PFA
PTFE offers many excellent properties and most chemicals won’t affect it, but its looser chemical structure can act as a sponge, over time letting chemicals seep through to the metal beneath it. We’ve developed a solution to that problem that solves many of our clients’ coating challenges: applying PTFE as a primer and PFA as a topcoat. PFA’s tighter chemical structure, when applied to a PTFE primer, creates an extremely strong barrier.
Xylan® by Whitford Worldwide
Xylan is a high-performance coating that’s well known for certain properties: nonstick and release, wear resistance, heat resistance, and lubrication. It’s not often thought of as a go-to coating for chemical resistance, but the Xylan family of coatings offers good resistance to acids and we recommend it frequently in situations where acid resistance is needed alongside other critical functional properties . In our experience, Xylans aren’t the best choice for alkalis and solvents, though.
Teflon® by DuPont
We like to say that Teflon offers the best balance of chemical resistance – it resists acids, alkalis and solvents well. If you’re using Teflon and chemical resistance is an issue, go for purity: the purer the Teflon, the better it resists chemicals.
Nylons aren’t known for chemical resistance properties. But in our work with nylon, we’ve found that in certain situations, nylon can resist acids fairly well, and some alkalis. The jury is still out on the chemical resistance of nylon, but if you need an autoclavable coating that resists acids, we might recommend you do a test with nylon.
ETFE / ECTFE
Coatings such as Tefzel® and Halar® offer excellent resistance to all chemicals including solvents, and are often thought of as the go-to coatings for chemical resistance. These coatings can be built up to high thicknesses, can be machined with high precision, and are extremely durable. In fact, both of these do well under radiation.
Kynar is a thick film barrier coating that is extremely durable. We recommend it for its resistance to halogens, alkalis and strong acids, but generally we don’t recommend it for solvent resistance. It’s a frequent choice for chemical processing equipment, the battery, semiconductor, wastewater, food and pharmaceutical industries.
Have a technical question or need more specific advice about what coating to use for your needs? Contact AIC’s COO Dave Arney at (866) 858-9881, or submit your question through our contact form.