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Preparation of copper phthalocyanine pigments of the beta-modification

  • US 5,175,282 A
  • Filed: 12/09/1991
  • Issued: 12/29/1992
  • Est. Priority Date: 07/11/1989
  • Status: Expired due to Fees
First Claim
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1. A process for preparing a strong, transparent and readily dispersible copper phthalocyanine pigment of the β

  • -modification consisting of grinding crude copper phthalocyanine in the absence of any grinding aids in the presence of from 1 to 10% by weight, based on the crude pigment, an organic liquid selected from the group consisting of di-C1 -C12 -alkyl phthalate, N-methylpyrrolidone, diethylene glycol, butoxyethanol, phenoxyethanol, ethylene glycol acetate, ethylene glycol diacetate and mixtures thereof, at from 90°

    to 140°

    C., and then recrystallizing the mill base in an aqueous organic phase.

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