Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
1999-06-24
2001-05-22
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S493000, C106S496000, C534S581000, C534S602000, C534S757000, C534S784000, C534S793000
Reexamination Certificate
active
06235100
ABSTRACT:
TECHNICAL FIELD
This invention generally relates to novel metallized azo yellow pigments made with two different aromatic amines and to the use of such pigments in plastics, paints and inks.
BACKGROUND OF THE INVENTION
Azo yellow pigments are a class of colorants that are tinctorially strong and relatively inexpensive. Monoazo yellow pigments show good lightfastness and are particularly useful as coloring agents for paints and some printing inks. In plastics, however, monoazo yellow pigments tend to undesirably bloom and discolor at high temperatures, so their use is disfavored. Disazo (diarylide) yellow pigments are much stronger tinctorially and show a much lower tendency to bloom and discolor at high temperatures. However, R. Az et al reports in
Dyes and Pigments,
15, 1 (1991), that diarylide yellows are degraded to potentially carcinogenic by-products (e.g., 3,3′-dichlorobenzidine) in plastics processed above 200° C., a temperature lower than that used in processing most plastics (many plastics are processed at temperatures from 250° C. to 330° C.). In attempts to overcome these disadvantages, azo pigment manufacturers have actively pursued development of new metallized azo yellows, analogous to the metallized azo red pigments that show good high temperature stability in plastics.
Two recent patents involve coupling diazotized 2-amino-5-chloro-4-methyl (or ethyl) benzene-1 -sulfonic acid into 1-substituted phenyl-3-methyl-5-pyrazolones and metallizing with calcium or strontium. Specifically, U.S. Pat. No. 5,669,967 to Hays involves coupling into 1-(2-chlorophenyl)-3-methyl-5-pyrazolone, while U.S. Pat. No. 5,746,821 also to Hays involves coupling into 1-(4-methylphenyl)-3-methyl-5-pyrazolone.
In the past two decades, there has been notable development activity in metallized azo yellow pigments involving coupling various diazotized 2-aminobenzene-1 -sulfonic acid derivatives into coupler 1-(3′-sulfophenyl)-3-methyl-5-pyrazolone (hereinafter 3-sulfo-PMP) and metallizing. For instance, German Offenlegungsschrift specification No. 2616981 (1977, BASF) relates to coupling the calcium salt of diazotized 2-amino-4,5-dichlorobenzene-1-sulfonic acid into 3-sulfo-PMP (Colour Index (C. I.) Pigment Yellow 183). U.S. Pat. No. 4,980,458 to Hari et al discloses the mixed sodium, ammonium or half-calcium salts of diazotized 2-amino-4,5-dichlorobenzene-1-sulfonic acid coupled into 3-sulfo-PMP. U.S. Pat. No. 4,594,411 to Henning discloses the calcium salts of diazotized 2-amino-5-acetylaminobenzene-1-sulfonic acid, 2-amino-5-methoxybenzene-1-sulfonic acid, 2-amino-5-methylbenzene- 1 -sulfonic acid or 2-amino-5-chlorobenzene-1-sulfonic acid coupled into 3-sulfo-PMP. U.S. Pat. No. 5,047,517 to Deucker discloses the calcium salt of diazotized 2-amino-4-chloro-5-methylbenzene-1-sulfonic acid coupled into 3-sulfo-PMP (C. I. Pigment Yellow 191). German Offenlegungsschrift 4111348 (1992, Sandoz) discloses the strontium salt of diazotized 2-amino-4-chloro-5-methylbenzene-1-sulfonic acid coupled into 3-sulfo-PMP. European Patent 0841 367A2 (1998, Clariant Finance Ltd.) relates to the use of this pigment in plastic packaging material.
U.S. Pat. No. 5,733,365 to Halko et al discloses treatment of titanium dioxide with di- C
2-20
alkyl sulfo-succinates, but describes Examples with only the well-known dioctyl sulfosuccinate.
Although a few of the metallized azo yellows made from 3-sulfo-PMP (e.g., C. I. Pigment Yellow 191) have been commercialized and show good fastness to heat and light in plastics, they suffer from low tinctorial strength (W. Herbst and K. Hunger,
Industrial Organic Pigments,
VCH, New York, 1993, pp. 236-237). For example, the pigment concentration required for coloring high density polyethylene containing 1% titanium dioxide to ⅓ Standard Depth of Shade is 0.32% for P.Y. 191 vs. only 0.08% for diarylide yellow P.Y. 83 (ibid, p. 255). Plastics processors using diarylide yellows are particularly conscious of the increased costs of using the higher concentrations of metallized azo yellows required for coloring plastics to the required shades. Thus, there is a need for metallized azo yellow pigments that show higher strength, as well as good heat stability and good lightfastness.
SUMMARY OF THE INVENTION
In one embodiment, the present invention relates to a medium shade yellow pigment composition comprising at least one compound having one of the following formulae:
wherein M is a divalent metal.
In another embodiment, the present invention relates to a method of preparing a medium shade yellow pigment composition comprising making an azo pigment by coupling (i) two or more diazonium components made from two or more aromatic amines including 2-amino-5-chloro-4-ethylbenzene-1 -sulfonic acid and 2-amino-4-chloro-5-methylbenzene-1-sulfonic acid with (ii) at least 1-(3′-sulfophenyl)-3-methyl-5-pyrazolone, and metallizing the azo pigment with a divalent metal to provide the medium shade yellow pigment composition.
In yet another embodiment, the present invention relates to a method of preparing a medium shade yellow pigment composition comprising making an azo pigment by coupling (i) two or more diazonium components made from two or more aromatic amines including from about 70% to about 92.5 mole % of 2-amino-5-chloro-4-ethylbenzene-1-sulfonic acid and from about 7.5% to about 30 mole % of 2-amino-4-chloro-5-methylbenzene-1-sulfonic acid with (ii) at least 1-(3′-sulfophenyl)-3-methyl-5-pyrazolone, and metallizing the azo pigment with an alkaline earth metal to provide the medium shade yellow pigment composition.
In still yet other embodiments, the present invention relates to plastics, paints or inks containing metallized azo yellow pigments according to the invention.
The pigments according to the present invention are very surprising because the use of specified amounts of at least two specifically defined aromatic amines is believed to impart high tinctorial and chromatic strength, good heat stability and good lightfastness.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to metallized azo medium shade yellow pigments suitable for use as a coloring agent, methods of making and using the metallized azo yellow pigments, and plastics, paints and inks containing the metallized azo yellow pigments. Metallized azo yellow pigments according to the present invention, made with at least two specifically defined aromatic amines, exhibit unexpectedly high tinctorial strengths, even higher than that of C.I. Pigment Yellow 191, while simultaneously exhibiting good heat stability. In addition, the metallized azo yellow pigments according to the present invention exhibit a combination of unexpectedly good heat stability and good lightfastness, in comparison to different metallized azo pigments. In many embodiments, the metallized azo yellow pigments according to the present invention contain few (no more than 2) halogen atoms per pigment molecule, so the metallized azo yellow pigments are environmentally friendly.
In one embodiment, the metallized azo yellow pigments according to the present invention are made by coupling a mixed diazo comprising 2-amino-5-chloro-4-ethylbenzene-1-sulfonic acid (hereinafter Ethyl C Amine as shown in Formula I) along with and in an amount greater than 2-amino-4-chloro-5-methylbenzene-1-sulfonic acid (hereinafter 2B Acid as shown in Formula II):
into 1-(3′-sulfophenyl)-3-methyl-5-pyrazolone (3-sulfo-PMP) and metallizing with a divalent metal such as strontium. In another embodiment, the metallized azo yellow pigments made by coupling a mixed diazo comprising from about 70% to about 92.5 mole % of Ethyl C Amine and from about 7.5% to about 30 mole % of 2B Acid. Unless other noted, all percentages are by mole percent. In yet another embodiment, the metallized azo yellow pigments made by coupling a mixed diazo comprising from about 75% to about 90% of Ethyl C Amine and from about 10% to about 25% of 2B Acid. In still yet another embodiment, the metallized azo yellow pigments made by coupling a mixed diazo compris
Engelhard Corporation
Keller Raymond F.
Klemanski Helene
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