A newly developed technique used to measure cohesive strength in pressure-sensitive adhesives (PSAs) has been developed. Ashland Performance Materials scientists developed a stress-relaxation method for calculating the cohesive strength of PSAs that reportedly offers significant advantages over other techniques.

Lars Kilian, Ph.D., senior staff scientist; and Charles M. Lewis, Ph.D., technical director, investigated and developed a new process that uses a texture analyzer to measure stress relaxation over a specific time, enabling the force retention (FR) value to be calculated. “This technique provides swift and reproducible measurements of cohesive strength directly from 1 mil PSA-coated stock,” said Kilian.

“Methods used prior to this discovery were often time-consuming, highly dependent on the operator’s skill and had poor repeatability on subsequent tests,” said Lewis. The results from Kilian’s and Lewis’ findings show, in part, that the texture-analyzer method eliminates these problems and that FR could be a predictor for key performance attributes, such as PSA converting ability.

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