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US 11,549,018 B2Granted
Pigment composition
AssigneeSanyo Color Works, Ltd.
InventorsJunichiro Sato, Takeshi Nishikawa
Life of this patent
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Abstract
A pigment composition contains: an azo pigment that is a reaction product between a coupler and a base; and a pigment derivative, and a content of o-anisidine derived from the coupler is less than or equal to 20 mg/kg in the entire pigment composition. A method for producing the pigment composition includes, after reaction between a coupler and a base to generate an azo pigment, or during the reaction between the coupler and the base, adding a remover for o-anisidine derived from the coupler.
Claims6
A method for producing a pigment composition, the method comprising:
- after reaction between a coupler and a base to generate an azo pigment, or during the reaction between the coupler and the base, adding a compound represented by formula (a) below as a remover for o-anisidine derived from the coupler,
- [Chem. 2]
- W2—COOW1 (a)
- wherein W1 represents an aliphatic hydrocarbon group and W2 represents a group having at least one carboxylic acid alkyl ester group, or an aliphatic hydrocarbon group having two or more carbon atoms;
- and
- washing the azo pigment with water after the addition of the compound represented by formula (a).
3 more elements
Dependencies are inferred from the claim text.