West Conshohocken, Pennsylvania -- A proposed ASTM standard on plastics will provide polyurethane raw material suppliers, customers and developers with a useful practice for setting up gel tests to determine the reactivity of materials.
The proposed new standard, ASTM WK34781, Practice for Gel Tests for Polyurethane Non-Foam Formulations, is being developed by Subcommittee D20.22 on Cellular Materials - Plastics and Elastomers, part of ASTM International Committee D20 on Plastics.
Polyurethanes are often used as adhesives and in coatings. David Mullen, process chemist with Rubicon llc, and a D20 member, notes that having some idea of the time it takes adhesives to bond and coatings to set helps to determine their suitability for different applications. Mullen says that many PU material suppliers and customers have their own methods for testing, including variations on a gel test.
"Measurement of gel time can give developers, suppliers and customers an idea of the reactivity of different polyurethane raw materials, mainly isocyanates and polyols, for purposes of identifying various applications and for use in quality control," said Mullen, in an ASTM statement.
According to Mullen, the task group typically works with analytical methods that involve wet chemistry, spectroscopic techniques and chromatography. Performance test methods such as WK34781 mark a departure for the task group's development of analytical-only testing, but could open areas for other types of performance test development.
The task group working on ASTM WK34781 is part of D20.22, but it also acts as the Polyurethane Raw Materials Analysis Committee of the Center for the Polyurethane Industry. Any parties interested in improving the analysis of polyurethane raw materials, particularly isocyanates and polyols, are invited to join in the ongoing development of ASTM WK34781.