Crystal forms of quinacridones made from 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone
Novel crystal forms of solid solutions of 2,9-dimethyoxyquinacridone and 2,9-dichloroquinacridone. The crystal forms may be formed by a process comprising the steps of: a) heating a mixture of 2,5-di(4-methoxyanilino)terephthalic acid, and 2,5-di(4-chloroanilino)terephthalic acid in polyphorsphoric acid at a temperature less than 1050 C to form a mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone; b) combining the mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone with water; and c) heating the mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone at a temperature not more than 110° C. Another crystal form may be formed by the process of heating a mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone in a polar aprotic solvent. These products are may be used for coloring fibers, plastics, paints, coatings, printing inks, color filters, cosmetics, automotive coatings, textiles, fibers, powder coatings, in-mold coatings, laminate films, and the like.
1. A pigment comprising 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone, that comprises crystal form Type III of quinacridones.
2. The pigment of claim 1 , made by the process of heating a mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone in a polar aprotic solvent, where a pH of the mixture has been adjusted.
3. The pigment of claim 2 , where the pH of the mixture in the polar aprotic solvent is not less than about 12.
4. The pigment of claim 2 , where the polar aprotic solvent is N-methyl pyrrolidone.
5. The pigment of claim 2 , where the mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone is heated to a temperature of not less than about 120° C.
6. The pigment of claim 2 , where the pigment in an automotive solvent basecoat/clearcoat paint system has CIE color coordinates of about 7.1≦a*≦about 23.1, about −28.1≦b*≦about −12.7, and about 19.0<C*<about 35.0.
7. The pigment of claim 2 , where the pigment comprises from about 10% to about 90% of 2,9-dimethoxyquinacridone and from about 90% to about 10% of 2,9-dichloroquinacridone.
8. The pigment of claim 2 , where the pigment comprises from about 25% to about 75% of 2,9-dimethoxyquinacridone and from about 75% to about 25% of 2,9-dichloroquinacridone.
9. The pigment of claim 2 , where the pigment has X-ray powder diffraction d-values at about 3.2 Å, about 3.3 Å, about 3.5 Å, about 3.9 Å, about 4.1 Å, about 4.4 Å, about 5.1 Å, about 5.6 Å, about 5.9 Å, about 8.8 Å, about 17.5 Å.
10. The pigment of claim 2 , where the pigment has X-ray powder diffraction d-values at about 3.2 Å, about 3.8 Å, about 3.9 Å, about 5.4 Å, about 5.6 Å, about 5.9 Å, and about 17.1 Å.
11. The pigment of claim 5 , comprising crystal form Types I and III of quinacridones.
12. The pigment of claim 5 , made by the process comprising the steps of:
a) heating a mixture of 2,5-di(4-methoxyanilino)terephthalic acid, and 2,5-di(4-chloroanilino)terephthalic acid in polyphosphoric acid at a temperature less than 105° C. to form the mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone;
b) combining the mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone with water; and
c) heating the mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone.
13. The pigment of claim 12 , where the pH of the mixture in water is not less than about 12.
14. A process comprising the step of heating a mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone in a polar aprotic solvent to a temperature of not less than about 120° C.
15. The process of claim 14 where a pH of the mixture in the polar aprotic solvent is not less than about 12.
16. The process of claim 14 , where the polar aprotic solvent is N-methyl pyrrolidone.