By Brad Dawson, Rubber & Plastics News Staff
Louisville, Kentucky -- Speciality chemicals supplier Sartomer Co. Inc. has added a thermoplastics urethane and a scorch-retarding elastomer coagent to its product offerings.
The 7840 TPU is diene-based and designed for the rubber and plastic markets, Exton, Pennsylvania-based Sartomer said, and enables formulators to apply urethane properties to standard rubber formulations. TPUs based on diene prepolymers present a new material form with both rubber-like soft segment and hard urethane linkages.
"The unique thing about this particular TPU is that the soft segments are polybutadiene, so it will act like a TPU but it will cure like an elastomer," said Chuck Mateer, marketing manager, Ricon & SMA Resins for Sartomer, at the ACS Rubber Division Mini-Expo, held 14-16 Oct in Louisville, Kentucky.
"So where TPUs are really good for adhesion and tie-layers, now you can get the adhesion to an elastomer where it will actually use the cure system from the underlying elastomer and give you the chemical bond, not just the physical bond."
The 7840 TPU can be processed using both standard rubber and thermoplastic equipment. Sartomer views the material as being ideal for tie-layers and has had requests to have it extruded into film, but it has many potential applications, Mateer said. These include polymer/rubber modification, barrier layers, adhesives and sealants, hoses and tubing, wire and cable, footwear and coatings.
Sartomer's other new product, SR533R, is a scorch-retarding version of triallyl isocyanurate. The coagent allows formulators to mitigate the rapid onset of scorch and increases in-process and cure scorch safety while maintaining cured physical properties, the company said.
Coagents for elastomers primarily are divided into Type 1 and Type 2, Mateer said, where Type 1s affect the state and rate of cure and Type 2s affect only the state, not the rate. TAIC historically is Type 2, yet Sartomer talked with customers and found that when used with FKM, it acts like a Type 1 coagent.
As a result, the company targeted fluoroelastomers as the niche for a scorch-retarding TAIC.
"It's not something we would have historically considered," Mateer said. "But we think it provides just enough to get you through an injection moulding cycle, where you need just a little bit of delay as you go through the process and get through your cycle before it cures."
SR533R is especially effective in the peroxide cure of elastomers for demanding applications like oil and gas exploration, aerospace seals, and automotive and off-road gaskets encountering high temperatures and pressures.
Both products are made in the US by Sartomer primarily for the US market, Mateer said.