Compositions: coating or plastic – Materials or ingredients – Pigment – filler – or aggregate compositions – e.g. – stone,...
Reexamination Certificate
2001-09-19
2002-12-17
Green, Anthony J. (Department: 1755)
Compositions: coating or plastic
Materials or ingredients
Pigment, filler, or aggregate compositions, e.g., stone,...
C106S031770, C106S031780, C106S493000, C106S494000, C524S090000, C546S056000, C548S453000
Reexamination Certificate
active
06494947
ABSTRACT:
The invention relates to crimson-coloured pigment mixtures comprising 1,4-diketo-2,5-dihydro-3,6-diaryl-pyrrolo[3,4c]pyrrole and quinacridone pigments in separate crystalline phases, having high tinctorial strength combined with other excellent application properties. The pigments according to the invention can be used in printing inks, especially in printing inks for polychromatic printed products.
Shade, tinctorial strength, transparency and viscosity are the most important parameters in printing inks. The shade must correspond to very specific values in order to be able to obtain together with other shades as broad a colour range as possible, there generally being used in addition to crimson (magenta) also blue-green (cyan), yellow and black. For that purpose the tinctorial strength and transparency should be high, but combined with acceptably low viscosity.
EP 337 435 discloses a process for the preparation of opacifying diketopyrrolopyrrole pigments by wet milling in an alcohol/base system, by means of which it is also possible to treat pigment red 254.
It is known from EP 277 914 that quinacridones with diketopyrrolo[3,4c]pyrroles in a ratio of from 5:95 to 95:5 yield solid solutions the colour properties of which differ from those of the components.
Those solid solutions are obtained by a variety of processes, including salt kneading in the presence of an organic solvent. The same result is also obtained by dry milling followed by heat treatment in the presence of a polar solvent (EP 524 904), by simultaneous decarboxylation of soluble derivatives (EP 654 506) and by dissolution and reprecipitation from basic dimethyl sulfoxide (EP 707 049), the ratio by weight of 2,9-dichloroquinacridone to 1,4-diketo-2,5-dihydro-3,6-di(4′-chlorophenyl)pyrrolo[3,4c]pyrrole in one Example of EP 707 049 being 3:2.
Finally, EP 737 723 discloses physical mixtures of 1,4-diketo-2,5-dihydro-3,6-di(4′-bi-phenylyl)pyrrolo[3,4c]pyrrole and 2,9-dichloroquinacridone that have a red shade and high opacity.
Those known products, however, have proved still to be insufficiently suitable for printing inks, especially for inks for polychromatic printing. The printing inks obtainable from the known pigments either are of an undesired shade or they are disappointing in terms of the tinctorial strength, transparency, viscosity or even several of those properties simultaneously.
It has now been found that pigment compositions can be obtained that are surprisingly more suitable for printing inks when certain 1,4-diketo-2,5-dihydro-3,6-diaryl-pyrrolo[3,4c]-pyrrole and quinacridone pigments are blended under conditions such that the crystal modifications of the components are substantially retained, that is to say without the formation of solid solutions or mixed crystals.
It has also been found that 1,4-diketo-2,5-dihydro-3,6-di(4′-chlorophenyl)pyrrolo[3,4c]-pyrrole and 2,9-dichloroquinacridone can, surprisingly, be surface-passivated by salt kneading so that particles conditioned in that manner no longer have a tendency to form solid solutions or mixed crystals, even when they are dispersed using high forces either together or with other quinacridones or pyrrolo[3,4c]pyrroles, respectively, as is customary in the preparation of printing inks.
The invention accordingly relates to a pigment composition comprising pigments of formulae
wherein R
1
, R
2
, R
3
and R
4
are each independently of the others hydrogen, chlorine, bromine, cyano, trifluoromethyl, C
1
-C
8
alkyl, C
1
-C
8
alkoxy or C
1
-C
8
alkylthio, wherein the pigments of formulae (I) and (II) have their own separate crystalline phases and at least one pigment of formula (I) or (II) is 1,4-diketo-2,5-dihydro-3,6-di(4′-chlorophenyl)pyrrolo-[3,4c]pyrrole or 2,9-dichloroquinacridone kneaded with a crystalline inorganic salt and a neutral organic liquid.
Separate crystalline phases are recognised by the fact that the X-ray diffraction pattern of the pigment composition corresponds to the weighted sum of the X-ray diffraction patterns of the pure components. It is probable, although unconfirmed, that the particles of different crystal modifications occur loosely adjacent to one another; however, aggregates of different crystal modifications likewise fully correspond to the definition according to the invention, provided they do not contain mixed phases or solid solution regions.
The pigment of formula (I) may be a chemically uniform compound, or may be a mixture, a solid solution or a mixed crystal of from 2 to 4 compounds of formula (I). The pigment of formula (II) may be a chemically uniform compound, or may be a mixture, a solid solution or a mixed crystal of from 2 to 4 compounds of formula (II), which may also contain from 0 to 20 mol % each of the compounds of formula
and/or
Instead of pure 1,4-diketo-2,5-dihydro-3,6-di(4′-chlorophenyl)pyrrolo[3,4c]pyrrole as component to be kneaded, there may also be used a monophase solid solution or a mixed crystal in which 1,4-diketo-2,5-dihydro-3,6-di(4′-chlorophenyl)pyrrolo[3,4c]pyrrole constitutes the host phase.
Instead of pure 2,9-dichloroquinacridone as component to be kneaded, there may also be used a monophase solid solution or a mixed crystal in which 2,9-dichloroquinacridone constitutes the host phase.
It is not advantageous, on the other hand, to use solid solutions or mixed crystals that comprise compounds of formulae (I) and (II) simultaneously.
When the pigments of formulae (I) and (II) are mixtures, solid solutions or mixed crystals, preference is given to as few components of formulae (I) and/or (II) as possible, for example 2 or 3 of each, preferably 2 of each, which each on their own or together form a stable crystal modification, especially physical mixtures and mixed crystals. Special preference is given, however, to a single compound of formula (I) or a single compound of formula (II), and very special preference is given to only one compound of each of formulae (I) and (II).
C
1
-C
8
Alkyl is, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-amyl, tert-amyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl or 2,4,4-trimethyl-2-pentyl, preferably C
1
-C
4
alkyl, especially methyl or ethyl. C
1
-C
8
Alkoxy is, for example, —O—C
1
-C
8
alkyl, preferably —O—C
1
-C
4
alkyl, especially methoxy or ethoxy. C
1
-C
8
Alkylthio is, for example, —S—C
1
-C
8
alkyl, preferably —S—C
1
-C
4
alkyl, especially methylthio or ethylthio.
R
1
, R
2
, R
3
and R
4
are preferably chlorine, bromine, cyano, C
1
-C
4
alkyl or trifluoromethyl, especially chlorine, methyl or cyano, more especially chlorine.
The pigment of formula (I) is preferably 1,4-diketo-2,5-dihydro-3,6-di(4′-chlorophenyl)-pyrrolo[3,4c]pyrrole and the pigment of formula (II) is quinacridone or 2,9-dichloro-quinacridone, especially 2,9-dichloroquinacridone. The preferred pigments of formulae (I) and (II) are especially preferably combined with one another.
The pigments of formulae (I) and (II) are known and some of them are commercially obtainable. The ratio by weight of pigment of formula (I) to pigment of formula (II) is preferably from 1.5:1 to 1:1.2, especially about 1:1.
For the kneading of the pigments of formula (I) or (II), preferably the ratio by weight of crystalline inorganic salt to pigment of formula (I) or (II) is from 4:1 to 12:1, the ratio of organic liquid to crystalline inorganic salt is from 1 ml:6 g to 3 ml:7 g, and the temperature is from −20 to 100° C. The pigment particles are advantageously reduced in size during kneading, with preferably a pigment of a specific surface area of ≦40 m
2
/g, especially from 5 to 30 m
2
/g, being converted to a pigment of a specific surface area of ≧40 m
2
/g, especially from 50 to 80 m
2
/g. The specific surface area can be determined, for example, by the nitrogen method.
Advantageously the crystalline inorganic salt is soluble in the neutral organic liquid at ≦100 mg/l at 20° C., especially ≦10
Grandidier Yves
Hauser Hanspeter
Ruf Klaus
Ciba Specialty Chemicals Corporation
Crichton David R.
Green Anthony J.
LandOfFree
Crimson-colored pigment composition and the utilization thereof does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Crimson-colored pigment composition and the utilization thereof, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Crimson-colored pigment composition and the utilization thereof will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2942271