A method for the preparation of a highly pure copper phthalocyanine red cast

摘要

The invention comprises the delta-crystal form of copper phthalocyanine which is characterized in that the portion of its X-ray diffraction spectrum lying between about 4.5 and 6.0 Angstrom units contains only one line of any considerable intensity, namely a line corresponding to an interplanar spacing of from 5.0 to 5.05 Angstrom units. The delta-crystal form is prepared by treating a finely divided copper phthalocyanine in alpha-crystal form with benzene or cyclo-1 : 3-hexadiene in the presence of a surface active agent and optionally in the presence of water. Specified surface active agents include sulphated or sulphonated derivatives of unsaturated compounds such as methyl oleate and castor oil and polyethenoxy derivatives of alcohols and phenols. Turkey Red oil is preferred. The delta-crystal form is redder in shade than previously known forms of copper phthalocyanine. Examples are given. U.S.A. Specifications 2,334,812, 2,486,351 and 2,770,629 are referred to.