Abstract: This application relates to a process for preparing quinacridones whereby the corresponding dihydroquinacridone is oxidized by subjecting a paste containing the dihydroquinacridone and an oxidizing agent to a high shear force mixing step.

Abstract: Binary and ternary pigmentary solid solutions are disclosed. The binary solid solutions are binary solid compounds consisting of 35-45 weight-percent unsubstituted DPP and 55-65 weight-percent dichloro DPP. The ternary solid solutions are guest-host solid solutions wherein the binary solid compound is the host and up to 30 weight-percent of a disubstituted quinacridone pigment is the guest. The binary and ternary solid solutions are useful as pigments for coloring high-molecular-weight organic materials; especially as replacements for perylene pigments in automotive finishes.

Abstract: An aqueous phase air oxidation process for the for the preparation of unsubstituted and substituted quinacfidone pigments is disclosed. The process involves an oxidation step wherein a 6,13-dihydroquinacridone is convened to the corresponding quinacfidone, utilizing a quinone compound and molecular oxygen as oxidizing agent, in a basic, aqueous reaction medium, in the presence of a nonionic, polar organic material which forms a second liquid phase in the basic reaction medium and which is present in a minor amount relative to the amount of aqueous base in the reaction medium. The quinacridones prepared by this process are useful as pigments.

Abstract: Aqueous processes for the preparation of a new beta quinacridone modification possessing a magenta color having C.I.E. color space values in masstone of L=33-36, A=34-40 and B=8-15 starting with the crude pigment and comprising several milling and alternative deaggregation and recrystallization steps, the latter being facilitated at elevated temperatures aided by the presence of base and minor amounts of crystal growth auxiliaries, and the beta quinacridone modification having the indicated C.I.E. color space values.

Abstract: Surface modification of a variety of pigments, particularly quinacridone pigments, and the pigments resulting therefrom whereby the pigment is treated with a poly(vinyl lower alkyl ether) and, optionally, with a dispersion-improving derivative of the primary pigment resulting in compositions exhibiting enhanced performance in automotive and other finish systems. The surface treatment also improves flow properties of the pigment in the aqueous phase of processing leading to higher solids content for direct application in waterborne systems.

Abstract: A process of reducing the particle size of oversize crude quinacridones to pigmentary grade material by ball or rod milling the crude quinacridone with 3-10 parts per part by weight pigment of borax pentahydrate and 5-40% by weight, based on pigment, of a monohydric alcohol containing 4-8 carbon atoms of a polyethylene glycol having a molecular weight of 150-600.

Abstract: Pigmentary grade quinacridone pigments are prepared from crude quinacridone by dry milling the crude quinacridone to form aggregated low crystallinity material followed by milling the low crystallinity in water using steel shot as the milling elements. In a preferred aspect of the invention from 0.5 to 5 wt percent, based on quinacridone, of phthalimidomethylquinacridone is present in the water milling step. In another preferred aspect of the invention the water milled pigment is extracted with a dilute hot acid in the presence of naphthenic acids and then dried.