6-(4-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinones of formula I ##STR1## where R.sub.1 and R.sub.2 are independently alkyl, cycloalkyl, aryl or aralkyl, R.sub.3 and R.sub.4 are independently hydrogen or alkyl, n is 1 to 4 and T is hydrogen, alkyl, substituted alkyl, alkylene or arylene, are effective in stabilizing organic materials against oxidative, thermal and actinic degradation.
公式I中的6-(
4-羟基苯基)-4,5-二氢-3(2H)-
吡啶酮,其中R.sub.1和R.sub.2分别为烷基,环烷基,芳基或芳基烷基,R.sub.3和R.sub.4分别为氢或烷基,n为1到4,T为氢,烷基,取代烷基,烷基烯或芳基烯,对于稳定有机材料抗氧化,热和光降解是有效的。