The effectiveness of intumescent fire retardant additives often depends on the amount of expansion generated, the temperature at which the onset of expanision occurs, and the ability of the intumescent to expand within the matrix. Expandable graphite flake is being used in a growing number of fire retardant ap[plications because its performance is superior to that of conventional chemical intumescents. Two new classes of exandable graphite, designated GRAFGuard~(TM) 160 and GRAFGuard~(TM) 22, have recently been developed by UCAR Carbon Company. These materials eshibit the highest expansion of any commercially available expandable graphite, at onset temperatures of 160 and 220 deg C. Based on processing and expansion requirements, either GRAFGuard~(TM) 160 or GRAFGuard~(TM) 220 can be selected to provide the optimum intumescent performance for fire retardant barriers, foams, or phastics.
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