METHOD FOR PROLONGING THE BREAKTHROUGH OF VOLATILE SUBSTANCES THROUGH ADSORBENT-CONTAINING AIR PURIFYING DEVICES

摘要

A method for prolonging the breakthrough of volatile substances, i.e. substances having a normal boiling point less than about 150.degree.C, through air purifying devices such as gas masks and chemical cartridge respirators, comprising utilizing as an adsorptive material in such device a particulate, substantially dust and contaminant free carbonized product prepared by (A) first partially dehydrochlorinating a normally crystalline vinylidene chloride polymer at temperatures below the melting point of such polymer to an extent of at least about 5 percent of theoretical HCl loss, then (B) completing the dehyarochlorination of such material, in the substantial absence of oxygen, by heating the material to carbonizing temperatures of from about 600.degree.C to about 1200.degree.C.