A novel class of halogenated phosphate fire retardants for use in polypropylene

Abstract

A novel class of 3,9-haloneopentoxy-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane-3,9-dioxides has been synthesized. The method of preparation and physical properties of the compounds are described. The chemicals have been found to be excellent fire retardants for polypropylene. A polypropylene composition meeting the UL-94 V-0 specification can be achieved on both 1/8 and 1/16-in.-thick specimens with as little as 15% addition of one of these compounds. The use of a typical inorganic synergist such as antimony oxide is not required. The spirodiphosphates described exhibit good light, thermal, and hydrolytic stability.