GB1085680A - Quinacridone compounds and pigment compositions containing them - Google Patents

Abstract

The invention comprises quinacridone compounds of formula <FORM:1085680/C4-C5/1> wherein the o-carboxybenzamidomethyl group are substituted for hydrogen on the terminal rings, m = 1-4, X is H, F, Cl, Br, CH3 or CH3O and R1 and R2 which are the same or different are H, F, Cl, Br, CH3 or CH3O; and quinacridone pigment compositions containing a mixture of said pigment and from 0.5 to 25% by weight based on the total composition weight of a compound of the above formula. The quinacridone compounds are prepared by heating a sulphuric acid solution of a quinacridone, a phthalimide and para-formaldehyde and precipitating from solution (e.g. by adding ice-water).ALSO:Alkyd resin coating compositions containing as pigments a mixture of a quinacridone pigment and from 0.5 to 25% by weight of the total pigment composition of a quinacridone compound of formula <FORM:1085680/C3/1> wherein the o-carboxybenzamidonmethyl groups are substituted for hydrogen on the terminal rings, m=1-4, X=H, F, Cl, Br, CH3 or CH3O and R1 and R2 are the same or different and are H, F, Cl, Br, CH3 or CH3O (see Division C4-C5), are described. A full shade red enamel is prepared by milling the quinacridone pigment composition with a coconut-oil modified non-oxidizing glyceryl phthalate resin (60% solution), naphtha and xylene; adding further resin, naphtha and xylene towards the end of the milling and finally adding the mixture obtained to a composition containing an alkyd resin as described above, a melamine-formaldehyde resin (55% solution), naphtha and xylene. This enamel is finally mixed with a white enamel containing TiO2 and the resin and solvent ingredients specified above.