High performance thermoset polymer specialist Volatile Free Inc. (VFI) has launched an innovative line of TDI Molding Rubbers to make the demolding process easier for precast concrete producers. Research has shown that users typically experience high breakage rates of concrete pieces or elements when casting into polyurethane rubber molds. With an opportunity to bring improvements to the urethane rubber market, the lab at VFI took the initiative to come up with a solution to reduce these breakage rates. Technicians ended up with a formula that provides enhanced releasing properties.
Their new Max Release Molding Rubbers are 25-50 A durometer polyurethanes with best-in-class release characteristics. They boast a MOCA-free formula with a convenient 1:1 mix ratio by volume. Liquid urethane rubbers are utilized in concrete casting due to their ability to replicate shapes, contours, and curves, creating highly realistic cast stone and manufactured stone veneer. After concrete is poured and allowed to cure, these premium rubbers demold the next day much easier than prior formulations. They also work well when powders and in-mold coatings are used to add unique color to the otherwise plain concrete mixture.
Compared to standard urethane rubbers, this new formula has a lower surface tension, which allows for easier demolding—a performance feature lowering the amount of release agent normally required and especially beneficial when high release agent content could affect the finished product. “This is the closest you can get to the release characteristics of silicone in a polyurethane, while also offering a cost-effective alternative,” says VFI Technical Director Michael Sullivan. “There haven’t really been many changes or improvements to the urethane rubber market since its creation. We feel that this is the first significant improvement in the industry. Testing has shown a substantially lower breakage rate on cast parts in the field, which equates to less material waste and longer-lasting molds.” Initial field testing indicates that there has been a 70 percent reduction in production breakage rates using the new VF-2141 TDI Molding Rubber, he notes, with users able to get down to as low as 2-3 percent breakage.
Customers who have field tested the new two-component urethane have asked to switch from old formulas, adds VFI Sales Manager Dana Gustafson. “It has a slightly higher price upfront, but the easier release will put less stress on the casting, which will extend the life of the molds,” he affirms. — Volatile Free Inc., Brookfield, Wis., 800/307-9218; www.volatilefree.com
