Claims
- 1. A process for improving the application properties of disazo pigments, which comprises adding sulfite ions to the weakly acid to neutral aqueous pigment suspension obtained in the coupling of a disazo pigment having a structure which corresponds to the formula ##STR2## in which R.sub.1 and R.sub.2 denote identical or different substituents from the group comprising methyl, methoxy, ethoxy and chlorine, X denotes a hydrogen or chlorine atom and m and n independently of each other denote 0 or an integer from 1 to 3 and then heating the pigment suspension for a half to two hours at 50.degree. to 100.degree. C.
- 2. The process as claimed in claim 1, wherein, in the formula, R.sub.1 and R.sub.2 denote methyl, methoxy or chlorine in the 2-, 4- or 5-position and X denotes a hydrogen atom.
- 3. The process as claimed in claim 1, wherein the disazo pigment is C.I. Pigment Yellow 83.
- 4. The process as claimed in claim 1, wherein the sulfite ions are added in the form of sulfur dioxide or as a soluble sulfite, hydrogensulfite or disulfite.
- 5. The process as claimed in claim 2, wherein the disazo pigment is C.I. Pigment Yellow 83.
- 6. The process as claimed in claim 2, wherein the sulfite ions are added in the form of sulfur dioxide or as a soluble sulfite, hydrogensulfite or disulfite.
- 7. The process as claimed in claim 3, wherein the sulfite ions are added in the form of sulfur dioxide or as a soluble sulfite, hydrogensulfite or disulfite.
- 8. The process as claimed in claim 5, wherein the sulfite ions are added in the form of sulfur dioxide or as a soluble sulfite, hydrogensulfite or disulfite.
Priority Claims (2)
Number |
Date |
Country |
Kind |
3128598 |
Jul 1981 |
DEX |
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3212105 |
Apr 1982 |
DEX |
|
Parent Case Info
This application is a continuation of application Ser. No. 398,896, filed July 16, 1982, now abandoned.
US Referenced Citations (7)
Continuations (1)
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Number |
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Parent |
398896 |
Jul 1982 |
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