| abstract |
A plastics composition comprising a high molecular weight material and an effective coloring amount of an azo pigment of formula ##STR1## where M is Mg, Ca, Sr, Ba or Mn or a mixture of two or more thereof, R 1 and R 2 are chlorine or methyl, x is zero or 1, y is zero or 1 and the sum of x and y is 1, with the proviso that when the high molecular weight material is polyvinyl chloride y is zero. |