Coating Wettability

A proposed ASTM International standard will allow manufacturers to make better use of portable goniometers to measure angles of drops of liquid when applied to a surface for testing the wettability of coatings, substrates, and pigments. ASTM’s paint and related coatings, materials, and applications committee (D01) is developing the proposed standard (WK72334).

“The ability to bridge the gap between the research and testing laboratory and the production line touches nearly every industry,” says ASTM International member Lucas Dillingham of BTG Labs “Being able to conduct reliable, accurate, quantitative and nondestructive testing of surface preparation for bonding, and to be able to conduct these tests directly on real parts in a manufacturing process, means the preliminary lab work can be more fruitful.”

According to Dillingham, the proposed standard will allow for wettability testing that can be done quickly and repeatedly on real parts, or real production lines, to prevent failures. For example, Frederick Fiddler, ASTM International member and technical manager with KRÜSS USA, notes that if contact angle measurements need to be taken on a large part in a factory or manufacturing facility, the new method will cover the use of a portable goniometer to take the measurement, rather than having the part dismantled for lab testing.

The proposed standard will be useful to any manufacturer concerned with bonding, coating, printing, painting, sealing or cleaning. Manufacturers will be able to use it to control supply chains by implementing surface quality checks of incoming materials. Regulatory bodies could find the proposed standard helpful in ensuring consistency of cleaning methods to create surfaces ideal for adhesion. Labs will use it to create a common language of validation between their testing and the testing done on actual production lines.