US Patent 7705078 Antimicrobial polymeric film

An anti-microbial polymeric film comprising a polymeric substrate layer and an inorganic anti-microbial compound of formula (I): AgaHbAcM2(PO4)3.nH2O wherein: A is at least one ion selected from an alkali or alkaline earth metal ion; M is a tetravalent metal ion; a is in the range 0.4 to 0.5; b and c are positive numbers such that (a+b+mc)=1; m is the valence of metal A; and 0≦n≦6, wherein the anti-microbial compound is present in the substrate layer in an amount of from about 0.05 to about 0.7% of by weight of the polymeric material of the substrate layer; and the use of said inorganic anti-microbial compound for providing an antimicrobial polymeric film having reduced haze.