DeKalb Molded Plastics Co. is molding recycled plastic and rubber into highway guardrail bumpers being used across the United States.
DeKalb of Butler, Ind., has begun molding the bumpers with a Uniloy structural foam molding press using recycled high density polyethylene and automobile tires. It expects the project will divert a minimum of 675 tons of HDPE and nearly the same amount of tires from Indiana's landfills annually.
The bumper blocks are sandwiched between metal guardrails and metal posts driven into the ground. DeKalb President and co-owner Jeff Rodgers said they are easier to install than the wood blocks they replace and, unlike the chemically treated wood blocks, don't pose disposal problems.
DeKalb ships the polymer bumpers to Trinity Industries Inc., a manufacturer of guardrail systems in Dallas. Although they address landfill issues in Indiana, the blocks can end up on highways across the country because they are approved by the Federal Highway Administration.
Rodgers said molding the bumpers is tricky because the raw materials do not mix well. DeKalb does not compound the materials but rather mixes them in the injection molding machine. Press screw design is key to get proper mixing, he explained. A small amount of chemical blowing agent is added in the machine to lower block weight and reduce internal stresses.
Indiana's Department of Commerce, through the Energy Policy Division, provided Dekalb with a $475,000 loan to fund half the cost of buying machinery for the bumper project. Rodgers said his firm is dedicating a press to the program, expected to run indefinitely.
Custom molder DeKalb had sales of $13.1 million for 2000.