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US 7,708,824 B2Granted
C. I. pigment red 57:1 and production process thereof
AssigneeDIC Corporation
InventorsAkihiro Ogata, Nagatoshi Kobayashi, Keiko Otsubo
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Abstract
In C. I. pigment red 57:1 of the present invention, the total content of 3-hydroxy-2-naphthoic acid and a metal salt thereof, which is measured by quantitative analysis using liquid chromatography, is 2,500 ppm or less as converted into the 3-hydroxy-2-naphthoic acid.
Claims2
A process for producing C. I. pigment red 57:1, comprising:
- conducting coupling of a diazonium salt of 4-aminotoluene-3-sulfonic acid and 3-hydroxy-2-naphthoic acid;
- and conducting laking with an inorganic calcium compound, wherein
- a molar ratio of the 4-aminotoluene-3-sulfonic acid:
- the 3-hydroxy-2-naphthoic acid is set within a range of 1.000:1.000 to 1.000:1.006, and
- the coupling is conducted by agitating so that a reaction ratio of the 3-hydroxy-2-naphthoic acid reaches 98.45% or more.
2 more elements
Dependencies are inferred from the claim text.