Compositions: coating or plastic – Materials or ingredients – Pigment – filler – or aggregate compositions – e.g. – stone,...
Reexamination Certificate
2000-08-28
2002-04-23
Green, Anthony (Department: 1755)
Compositions: coating or plastic
Materials or ingredients
Pigment, filler, or aggregate compositions, e.g., stone,...
C106S402000, C106S494000, C106S031800, C534S581000, C534S602000, C534S883000, C524S190000
Reexamination Certificate
active
06375733
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to novel azo blue shade red to magenta pigments, processes for their preparation and to coating, plastic and ink compositions containing such pigments.
BACKGROUND OF THE INVENTION
Azo pigments are a class of colorants that are tinctorially strong and relatively inexpensive. Commercially available heat stable azo pigments commonly used in plastics are limited to the color range of yellow, orange and red shades such as Pigment Yellow 61, Pigment Yellow 62, Pigment Yellow 183, Pigment Yellow 191, Pigment Yellow 205, Pigment Yellow 206, Pigment Yellow 209, Pigment Yellow 209:1, Pigment Yellow 210, Pigment Yellow 212, Pigment Orange 79, Pigment Red 276, Pigment Red 277, etc. Consequently, there is an unmet need to extend the shade range of azo pigments to magenta color pigments that show comparable performance in properties such as color strength, resistance to polar solvents, light fastness and/or heat stability. It is desirable to extend the shade range of azo pigments to a magenta color and thereby increase the range of colors available using such pigments.
SUMMARY OF THE INVENTION
This invention relates to blue shade red to magenta pigments suitable for use as coloring agents, and processes for their preparation. The magenta azo pigments of the present invention have excellent heat stability, bleed fastness and very high color strength. As a result, these pigments are suitable for use in the pigmenting of plastics, inks and coatings, among other materials, but especially in plastics where exposure to high temperatures is often encountered.
One aspect of the invention relates to a composition containing at least one compound characterized by the formula:
wherein R is a lower alkyl group or a hydroxycarbyl group, R
1
is hydrogen, chloro, a lower alkyl group, or a lower alkoxy group, and M is Ca, Sr, Ba, Mn, Mg or Zn.
Another aspect of the invention relates to a process for preparing an azo pigment involving the steps of coupling at least one diazonium component of one or more aromatic amines, wherein at least one aromatic amine has the formula:
wherein R is a lower alkyl group or a hydroxycarbyl group and R
1
is hydrogen, chloro, a lower alkyl group, or a lower alkoxy group with at least one hydroxynaphthalenesulfonic acid coupling component to form an azo dye; and metallizing the azo dye with a divalent metal.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to metallized azo blue shade red to magenta pigments suitable for use as a coloring agent, methods of making and using the metallized azo magenta pigments, and plastics, coatings and inks containing the metallized azo magenta pigments. Metallized azo magenta pigments according to the present invention exhibit high tinctorial strengths while simultaneously exhibiting good heat stability. In addition, the metallized azo magenta pigments according to the present invention exhibit a combination of good heat stability and good lightfastness, in comparison to different metallized azo pigments. In many embodiments, the metallized azo magenta pigments according to the present invention contain few (no more than about 1) halogen atom per pigment molecule, so the metallized azo magenta pigments are environmentally friendly.
Generally speaking, the azo pigments of the present invention are prepared by initially diazotizing one or more aromatic amines suitable for use in this invention and thereafter coupling the diazonium component with a coupling component suitable for use in this invention to form the desired dye. The dye can be metallized by any suitable means, as described more fully below.
Aromatic amines suitable for the present invention are those characterized by the formula:
wherein R is a lower alkyl group or a hydroxycarbyl group and R
1
is hydrogen, chloro, methyl, ethyl or lower alkoxy group. Hydroxycarbyl groups include hydroxyalkyl groups, hydroxyalkenyl groups, and the like. Lower alkyl groups and lower alkoxy groups contain from 1 to about 4 carbon atoms. Examples include methyl, methoxy, ethyl, ethoxy, propyl, propoxy, butyl and butoxy (all isomers included). One or more of the aromatic amines characterized by Formula (II) may be employed when making the azo magenta pigments of the present invention.
Examples of the aromatic amine include 2-amino-5-methoxy-benzenesulfonic acid; 2-amino-5-ethoxy-benzenesulfonic acid, 2-amino-4-chloro-5-methoxy-benzenesulfonic acid; 2-amino-4-chloro-5-ethoxy-benzenesulfonic acid; 2-amino-4-methyl-5-methoxy-benzenesulfonic acid; 2-amino-4-ethyl-5-methoxy-benzenesulfonic acid; 2-amino-4,5-dimethoxy-benzenesulfonic acid; 2-amino-4-methyl-5-ethoxy-benzenesulfonic acid; 2-amino-4-ethyl-5-ethoxy-benzenesulfonic acid; and 2-amino-4,5-diethoxy-benzenesulfonic acid.
In one embodiment, mixtures of two or more aromatic amines, wherein at least one of the amines is characterized by Formula (II), are diazotized, then coupled with the hydroxynaphthalenesulfonic acid coupler. In this embodiment, aromatic amines that are not characterized by Formula (II) are supplemental aromatic amines. Such supplemental aromatic amines can be useful for shade adjustments of the pigments of the present invention.
A variety of suitable supplemental aromatic amines can be mixed with aromatic amines characterized by Formula (II) for the purposes of the present invention. In one embodiment, the supplemental aromatic amines include primary aromatic amines wherein the aromatic moiety of the amines contains at least one substituent acid group or salts thereof, and preferably the alkali metal or ammonium salts of such supplemental aromatic amines. The aromatic amines may be monoamines or polyamines containing up to about four or more amine groups per molecule. Thus, the diazonium components derived from such supplemental aromatic amines may contain one diazonium group (mono-diazonium), two diazonium groups (bis-diazonium), three diazonium groups (tris-diazonium), etc. The supplemental aromatic aromatic amines may be monocyclic amines such as aniline and its derivatives, or bicyclic amines such as naphthyl amines and their derivatives. The supplemental aromatic aromatic amines may also be biphenylamines or polyamines such as aminobiphenyl, benzidine, and 3,3′,4,4′-biphenyltetramine.
In another embodiment, the supplemental aromatic amine is a primary aromatic amine characterized by the formula
wherein each R
2
is independently a halogen, hydrocarbyl, hydrocarbyloxy, carboxylic acid ester, sulfonic acid ester, carboxylic acid amide, imidazolone, sulfonic acid amide or nitro group; n is 0, 1 or 2; each Z is independently a —COOH or —SO
3
H group, or salts of such groups; m is 1 or 2; wherein it is understood that the imidazalone group is represented by the formula —NH—C—NH— which, when taken together with the aromatic ring, the nitrogen atoms are bonded to adjacent carbons to form a five member ring, and Formula (III) is not an aromatic amine characterized by Formula (II). The term “hydrocarbyl” as used in this specification and claims is intended to include hydrocarbons which may contain heteroatom containing substituent groups such as ether, ester, hydroxy, nitro or halogen which do not materially affect the hydrocarbon character of the group. The hydrocarbyl and hydrocarbyloxy groups typically contain from 1 to about 20 carbon atoms.
In another embodiment, the supplemental aromatic amines characterized by Formula (III) contain 0, 1 or 2 R
2
groups which are each independently a halogen, hydrocarbyl, hydrocarbyloxy, carboxylic acid ester, sulfonic acid ester, carboxylic acid amide, imidazolone, sulfonic acid amide or nitro group. The halogen group can be any of the halogens, although chlorine and bromine are generally used, with chlorine being the most preferred example of a halogen substituent. The hydrocarbyl groups may independently be alkyl, cycloalkyl, aryl, aralkyl or alkaryl groups containing from 1 to about 20 carbon atoms. For example, if R
2
is an unsubstituted aryl group, the aromatic amine is a biphenyl amine. When R
2
is an alk
Engelhard Corporation
Green Anthony
Keller Raymond F.
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