Suppression of Mold Shrinkage in Colored Plastics by Partial Chlorination of Phthalocyanine Pigments

The effect of partial chlorination of phthalocyanine pigments on the suppression of mold shrinkage in colored plastics has been investigated. Two to 14 Cl substituted phthalocyanines prepared by chlorination in AlCl3/NaCl melt (eutectic blend) were found to be effective in suppressing the mold shrinkage of colored plastics. On the other hand, partially chlorinated phthalocyanines prepared in trichlorobenzene gave no noticeable effect on the suppression of the mold shrinkage. In addition, the chlorination was found to proceed up to 10 substitutions.