Ciba-geigy Corporation

E.i. Dupont De Nemours and Company

Ciba Specialty Chemicals Corporation

James B Ganci

Shivakumar Basalingappa Hendi

Edward E Jaffe

Sebastian Vito Mastrangelo

Walter C Zukowski

Suruliappa Gowder Jeganathan

The present invention relates to a process for producing alpha, gamma-I, gamma-II and gamma-III crystal modifications of quinacridone and transparent quinacridone pigments including the solid solutions of various quinacridones, using a variety of tris-aryl-s-triazines, particularly resorcinol triazine derivatives, or aromatic- or heteraromatic-compounds having at least one hydroxyl or keto group bonded to the ring, as an additive, prior to or concurrently with the oxidation of corresponding dihydroquinacridone salts.

Use of aromatic compounds as phase directors and particle size reducers for quinacridone pigments

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.

Process for preparing quinacridones

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.

Pigmentary solid solutions of pyrrolo[3,4-c]pyrroles and quinacridones

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.

Process for the preparation of quinacridones from dihydroquinacridones

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.

Aqueous process for preparation of modified beta quinacridone

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.

Surface modified pigment compositions

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.

Borax dispersion milling of quinacridones

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.

Aqueous milling of quinacridone pigment

Elastic resistor compositions comprising metallic-conductive particles and solid conductive lubricant particles codistributed in a matrix of a curable, elastomer-forming polymer and the cured compositions formed therefrom. Elastic resistors made from said compositions are also disclosed.

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Wilmington, DE, United States of America

James B Ganci