The PRA is the world’s most complete surface coatings advisor. Since 1926, we have provided independent knowledge-based services and unrivalled technical expertise to drive innovation and growth.
Challenge
PRA was approached by a company who was looking to replace an existing isocyanate cured coating. While it had been used successfully in a radioactive environment for many years, the company wanted to explore potentially beneficial new alternatives. Having used the PRA in the past for corrosion testing, the client’s technical project manager chose the PRA for the comparative trial following a tender. The reason for his choice was that we are one of only a few organisations in the UK able to offer both preparation of the panels – for grit blasting and airless spraying – and the testing of the coatings.
Action
Two candidate replacement paint systems – together with the existing system – were applied to steel and glass substrates. The PRA carried out flexibility, impact, abrasion, accelerated ageing (involving heat and exposure in QUV weatherometer) and cold wall tank lining corrosion testing. In doing so, we provided un-aged, aged and abraded panels for the specialist irradiation and decontamination testing.
Results
Compared to the existing coating, results for the two candidate systems were disappointing. They proved to be more brittle and susceptible to mechanical damage. One of the alternatives also proved prone to yellowing when exposed to heat. Degradation and delamination of the topcoat was also observed with the candidate systems after the irradiation testing. Given the critical importance of the application, the tests revealed weaknesses in the two candidate coatings that makes them unlikely to be adopted without further development.
