ROLLER SUPPLIERS MAKE CASE FOR TPEs

By Brad Dawson, Rubber & Plastics News Staff

May 20, 2002

The use of thermoplastic elastomers in roll making is on the minds of industry suppliers and manufacturers, and two firms are helping to make the concept real and practical.

Roller machinery maker Roller Equipment Manufacturing Co. Inc. has introduced a thermoplastic roll builder, and rubber and plastic compound supplier PolyOne Corp. has developed a line of TPE materials specifically for the roller industry.

The two companies combined efforts at an open house demonstration held at Remco's Grandview, Mo., facility May 7, in conjunction with the Rubber Roller Group meeting in Kansas City, Mo. The event allowed roller manufacturers to see PolyOne's TPE materials processed on Remco equipment, particularly the firm's new TPB100X thermoplastic builder.

The machine-which can use a variety of TPEs-makes the roll via strip building and is similar to other Remco roll builders that apply and process thermoset rubbers prior to vulcanization.

The TPB100X utilizes a plastic extruder to heat, mix and extrude a TPE onto a conveyor belt, which transports the strip to the roller; the strip then is applied to the roller using a specially designed applicator head.

Remco's thermoplastic roll builders will process normally at about 8-10 pounds per minute, much like its rubber builders, said company president J. Dean Armstrong Jr. The extruders will come in 21/2-, 3- and 31/2-inch sizes, and initial lead time for the TPE builders will be about 120 days, Armstrong said.

While Remco has been looking into developing a TPE machine for rollers over the past decade and Armstrong began discussing an experimental model last year, PolyOne's entry was more deliberate. Steve Chase, sales manager for the firm's Texas-based Chase Elastomer unit, said only six months ago he didn't believe there was a place for TPEs in the rubber roller market and wasn't convinced it would work.

But after learning more about the benefits of thermoplastics in cost and other areas, Chase and PolyOne were convinced both TPEs and thermoset rubbers ``have a significant role to play in this industry,'' he said.

What supporters like about TPEs-which include thermoplastic olefins and urethanes-in roller applications are the best attributes of plastics and rubber. For example, the plastics side provides benefits in material/volume cost and time savings, while the rubber side gives top ``physical reinforcement,'' Chase said.

For example, curing time of a thermoset rubber material can take six to 24 hours, while a thermoplastic cure takes no longer than two hours, he said.

Carl McAfee of McAfee Consulting, who has been consulting with PolyOne, said TPEs provide ``properties that are good enough at prices that are attractive.'' TPEs generally are processed at intermediate temperatures-though higher than normal for rubber-generally come in small pellet form and can be processed similar to current roll-building techniques with slight modifications, McAfee said.

He added TPEs were not the best solution for higher end, demanding roll conditions.

The real challenge for suppliers like Remco and PolyOne will be to find roll manufacturers who want to invest in roll-building equipment for TPEs, which have extrusion temperatures in the 300-400 degree range, Chase said. ``That's the biggest limitation right now. But we've been encouraged by the level of interest.''

PolyOne's material offerings are limited for now, but do include thermoplastic blends with EPDM and SBR, as well as polyester and polyether, Chase said. The firm has its Elastamax-brand line of TPUs with a range of hardnesses, and is investigating blends for nitriles as well, he said.