Claims
- 1. A process for converting a pigment selected from the group consisting of isoindolinone, azo, quinophthalone, metal complex and quinacridone pigments into another crystalline modification, which consists essentially of suspending the pigment in a liquid alkylamine of the formula R.sub.1 --NH--R.sub.2, wherein R.sub.1 is hydrogen, methyl, or ethyl and R.sub.2 is methyl, ethyl, n-propyl, isopropyl, sec-butyl or tert-butyl, provided R.sub.1 and R.sub.2 contain a total of 1 to 4 carbon atoms, in the absence of water, stirring the suspension until conversion into the other modification is complete and isolating the crystalline modification by direct evaporation of the alkylamine.
- 2. A process for converting a pigment selected from the group consisting of isoindolinone, azo, quinophthalone, metal complex and quinacridone pigments into another crystalline modification, which consists essentially of suspending the pigment in a liquid alkylamine of the formula R.sub.1 --NH--R.sub.2, wherein R.sub.1 is hydrogen, methyl, or ethyl and R.sub.2 is methyl, ethyl, n-propyl, isopropyl, sec-butyl or tert-butyl, provided R.sub.1 and R.sub.2 contain a total of 1 to 4 carbon atoms, in the absence of water, stirring the suspension until conversion into the other modification is complete and isolating the crystalline modification by filtration and subsequent evaporation of the alkylamine.
- 3. A process as claimed in claim 1 or claim 2 wherein the pigment is treated with liquid methylamine, ethylamine and dimethylamine.
- 4. A process as claimed in claim 1 or claim 2 wherein undissolved pigment is isolated and freed from solvent before the alkylamine is removed by evaporation.
Priority Claims (1)
Number |
Date |
Country |
Kind |
1317/77 |
Feb 1977 |
CHX |
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Parent Case Info
This is a continuation of application Ser. No. 873,583 filed on Jan. 30, 1978, now abandoned.
US Referenced Citations (11)
Foreign Referenced Citations (2)
Number |
Date |
Country |
40-50699 |
Jan 1965 |
JPX |
900757 |
Jul 1962 |
GBX |
Non-Patent Literature Citations (1)
Entry |
Iwamoto et al., Chemical Abstracts, vol. 85, No. 22846m (1976). |
Continuations (1)
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Number |
Date |
Country |
Parent |
873583 |
Jan 1978 |
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