In the semiconductor and solar industry, chemical cleaning and etching processes connected with wafer production require the use of highly aggressive acids. Organic impurities are usually removed in dip tanks with the help of strongly oxidising acids such as peroxymonosulphuric acid, also known as ‘piranha acid’.The name speaks for itself: 'piranha acid' eats right through organic material. Careful testing of the structural material is crucial when designing process tanks for that type of critical media.
Designers of chemical plants rely on PVDF materials from Röchling, namely Polystone® PVDF and SUSTAPVDF, when working with highly aggressive acids, high operating temperatures and high mechanical loads. Thanks to their exceptional resistance to chemical media, they contribute to performance, reliability and a high level of operational safety.

In chemical plant engineering, large tanks and pressure vessels are often made from fibreglass-reinforced plastics combined with a thermoplastic liner as a chemical-resistant protective layer, due to the composite’s higher mechanical strength. PVDF is backed with a fabric for precisely this reason. Röchling offers Polystone® PVDF with a choice of either a polyester backing (SK) or, for heavily permeating media and/or high temperatures, a fibreglass backing (GK). As an interior liner, it therefore forms a very strong bond with GFK and steel tanks.
Procedures for testing the strength of the bond between the thermoplastic liner and the GFK laminate are described in DIN EN 13121-3.

More information on testing in composite construction.

• High mechanical strength, rigidity and toughness
• Outstanding resistance to acids
• High temperature resistance
• Very good resistance to ageing
• High purity
• Good abrasion resistance
• Very good UV resistance
• Very good welding properties

Polystone® PVDF and SUSTAPVDF are now available from stock in many designs and sizes.