PURPOSE: To obtain the composition having a good low temperature resistance and heat resistance, useful for a hose for lubricating oil, hose for fuel, diaphragm, packing and gasket in an automobile, by adding a specific trimellitic acid alkyl ester to a hydrogenated nitrile rubber.
CONSTITUTION: This composition is obtained by adding at least one of trimellitic acid alkyl ester compounds of the formula (R1-R3 each is a 7-8C straight chain alkyl) to a hydrogenated nitride rubber (e.g. a hydrogenation product of acrylonitride-butadiene copolymer), preferably by 5-70(wt.)pt. to 100 pt. of the rubber component.