and petroleum jelly hours to degradation composition composition composition b c dtest conditions initial final initial final initial final__________________________________________________________________________no exposure to petroleum jelly 21 45 358 382 887 990after exposure to un stabilized petroleum jelly sup c 17 41 161 211 425 522after exposure to stabilized petroleum jelly sup d 17 41 161 185 211 594 666__________________________________________________________________________ sup c witco 13 manufactured by witco chemical company sup d witco 13c manufactured by witco chemical company the procedure of example 19 was repeated except that polypropylene resin was used instead of high density polyethylene and the petroleum jelly treated specimens were oven aged at 150 u00b0 c the amounts of polypropylene antioxidant and n n 39 bis phthalimido oxamide in each composition tested are indicated in table vi below and the results are complied in table vii table vi______________________________________components in parts composition e composition f______________________________________polypropylene sup a 100 0 100 0antioxidant sup b 0 2 0 2n n 39 bis phthalimido oxamide 0 1______________________________________ sup a profax 6501 manufactured by hercules incorporated sup b irganox 1010 manufactured by ciba geigy table vii______________________________________stabilization of polypropylene in contact withcopper and petroleum jelly hours to degradation composition e composition ftest conditions initial final initial.