Eastman, Lubrizol improve adhesion strength of TPEs using sustainable materials

Kingsport, Tennessee-based Eastman and Wickliffe, Ohio-based Lubrizol say they have successfully partnered on improving adhesion strength of thermoplastic elastomers (TPEs) overmolded onto Eastman Tritan copolyester TX1501HF.

The collaboration stemmed from a mutual recognition of overmolding’s importance in manufacturing while delivering improved product performance and aesthetics in consumer goods when using Eastman’s sustainable Tritan Renew and Lubrizol’s Estane Eco renewably sourced TPU.

The companies researched how specific processing variables impact the adhesion strength of overmolded samples produced through 2K injection molding. They say the study’s findings are believed to be applicable across various TPE and substrate combinations, adding that this is of particular interest when mechanical interlocks cannot be used, and material changes are not feasible but improvements in adhesion strengths are desired.

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By optimizing key TPE processing variables like mold temperature, pack and hold time and TPE barrel temperature, the companies say their research team achieved a 124 percent improvement in adhesion strength compared to values obtained using nonideal processing conditions. They say an additional adhesion strength improvement was observed when Lubrizol’s Estane Eco 12T80E and 16T85 TPU grades were used. These grades displayed the highest peel strength values of all TPEs evaluated in this preliminary study.

“This was a unique opportunity for two leading material companies to leverage sustainable multimaterial solutions that enable customer innovations and expand the limits of consumer product experiences,” says Vince Haas, Lubrizol’s engineered polymers senior business director.

Courtland Jenkins, Eastman’s commercial director for engineered solutions, says, “This effort has advanced our understanding of overmolding and TPEs, providing valuable guidance for engineers and manufacturers looking to improve overmolded product strength. These findings open doors for new and innovative product designs, particularly when using recycled content.”

A detailed view of the study can be found here.