Patent ID: 8859643

Claim:
A process for producing particles which comprise at least one halogen-free flame retardant which is liquid under standard conditions and at least one metal oxide or semimetal oxide, which comprises the following steps: (A) producing an aqueous emulsion comprising the at least one flame retardant and at least one precursor compound of the at least one metal oxide or semimetal oxide, (B) forming core-shell particles, where the at least one flame retardant is present in the core and the at least one metal oxide or semimetal oxide is present in the shell of the particles, where the at least one flame retardant is present in the core and the at least one metal oxide or semimetal oxide is present in the shell of the particles, and (C) optionally drying the core-shell particles from step (B), wherein the at least one halogen-free flame retardant is triphenylphosphine, diphenyl(o-tolyl)phosphine, tributylphosphine oxide, trioctylphosphine oxide, diphenyl phosphite, triphenyl phosphite, tri(nonylphenyl)phosphite, dimethyl methylphosphonate, dioctyl phenylphosphonate, triphenyl phosphate, tritolyl phosphate, or mixtures thereof, or is resorcinol bis(diphenyl phosphate), bisphenol A bis(diphenyl phosphate), poly(m-phenylene methylphosphonate), or mixtures thereof, wherein the at least one metal oxide or semimetal oxide is SiO 2 , TiO 2 , ZnO, ZrO 2 , Al 2 O 3 , or mixtures thereof.