Safety razor steel blades remain in limited production for lower income markets. Because Gillette held a patent on stainless blades but had not acted on it, the company was accused of exploiting customers by forcing them to buy the rust-prone blade. The risk of injury from handling razor blades was further reduced in 1970 when Wilkinson released its "Bonded Shaving System", which embedded a single blade in a disposable polymer plastic cartridge. A flurry of competing models soon followed with everything from one to six blades, with many cartridge blade razors also having disposable handles. Cartridge blade razors are sometimes considered to
American Safety Razor Company building at 333 Jay Street then became the new campus for the Polytechnic Institute of Brooklyn. Seeking diversification Philip Morris acquires American Safety Razor in 1960. In 1963 American Safety Razor is the first maker of stainless steel blades, which were sold under the Personna brand name. In 1968, Philip Morris, purchased the Burma-Vita Company, makers of Burma-Shave. In 1970, the first blade made with tungsten steel was introduced, the Personna 74. In 1974 American Line Brand of industrial products was introduced, expanding the company into industrial blades. In 1977, executives purchased Personna American Safety Razor Company from Philip Morris