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US 6,784,286 B2Granted
Transparent greenish yellow pyrazolone pigments
AssigneeBASF SE
InventorsPeter Blaschka, Günter Smeyts, Paul Günthert
Life of this patent
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Abstract
The invention relates to pyrazolone pigments of general formula (I), wherein the radicals R1, R2, R3 and R4 independently represent hydrogen, chlorine, methyl or ethyl, whereby at least one of the radicals R1-R4 is different from hydrogen. The inventive pigments are characterised by a CIELAB colour angle of 80-85°, a chroma of 58-62 and a luminosity ≧87 (measuring angle 45°, standard illuminant D65).
Claims14
A pyrazoloneazo pigment of formula I
- wherein R1, R2, R3 and R4 are independently hydrogen, chlorine, methyl or ethyl, with the proviso that at least one of R1 to R4 is not hydrogen, and having a CIELAB hue angle of from 80 to 85°, a chroma of from 58 to 62 and a lightness of ≧87 (45° measuring angle, D65 illuminant) and which has the form of thin acicular crystals having a needle length of from 0.8 to 2.5 μm and a needle thickness of from 0.1 to 0.2 μm.
Dependencies are inferred from the claim text.