ALEXANDRIA, Va., March 26 -- United States Patent no. 12,258,461, issued on March 25, was assigned to Omya International AG (Oftringen, Switzerland).
"Bitumen product" was invented by Hartmut Kremer (Wernberg, Austria).
According to the abstract* released by the U.S. Patent & Trademark Office: "A bitumen product including bitumen and a mineral filler. In order to reduce the specific weight of the bitumen product while allowing sufficient scaling effect, the mineral filler contains expanded perlite grains, the expanded perlite grains having a closed-cell surface, and the expanded perlite grains having a closed-cell surface are not ground."
The patent was filed on Sept. 23, 2020, under Application No. 17/642,805.
*For further information,...