CLERMONT-FERRAND, France—An inner coating of polyurethane designed to eliminate noise from automobile tires is the subject of an international patent application by Michelin.
The innovation was filed with the World Intellectual Property Office under patent number WO/2013/182477 earlier in 2013 and published on the organization's website in December.
The French firm outlined details of the specific polyurethane foam used in its application.
According to the filing, "The polyurethane is based on a diphenylmethane diisocyanate (MDI), in particular on 4,4'-diphenylmethane diisocyanate and a polyol which has an ethylene oxide content greater than 50 percent (percent by weight).
"This specific polyurethane formulation makes it possible to obtain a light foam which efficiently absorbs noise. It has the advantage of being simple and inexpensive and of being easy to use by direct casting of the reagents in the tire of the invention."