To this end, Durable Products, Crossville, Tenn., and Bayer MaterialScience (BMS) LLC, Pittsburgh, developed sound-attenuating polyurethane floor mats that are more economical than those traditionally made from rubber.
The roughly 5-ft2 mats are reaction-injection-molded (RIM) Bayflex XGT-2 polyurethane. They weigh in at 35 and 40 lb and are molded into entire floor coverings for inside cabs of trucks and heavy construction vehicles. A sound-absorbing foam called Bayfit SA 511 can be added to the underside of the mat to further dampen sound and vibrations.
The polyurethane RIM process gives more design freedom than she et-compounde d rubbers. Molders can vary the thickness of the custom floor coverings something not possible with rubber. Molders make the mats thicker near the engine compartment and other key areas to improve driver comfort and damp sound and vibration. By the same token, thinner mats where possible help reduce weight, important with the ever-rising price of diesel.
Additionally, RIM makes it practical to mold large, complex components with undercuts, molded-in lips at the edges, and support struts that sheet molding can’t produce. Polyurethane can also be pigmented, so there won’t be wear spots in high-use areas.