Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
1999-07-20
2001-01-16
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031760, C106S031780, C106S031860, C106S031870
Reexamination Certificate
active
06174357
ABSTRACT:
TECHNICAL FIELD
This invention relates to ink compositions. More particularly, the invention relates to pigment-based ink compositions comprising a red pigment, a bishydroxy terminated thioether and a lactam. The invention further relates to a method of providing a large color gamut by increasing the chroma of an ink.
BACKGROUND ART
It is desirable to have a large color gamut for color printing. “Color gamut” refers to the number of colors which may be reproduced from a set of primary colors. The larger the color gamut, the more colors which can be successfully reproduced. The color gamut is a function of the chromas of the primaries. “Chroma” refers to the degree of saturation of the color. Providing high chroma primary inks will provide a large color gamut. A chroma value of a primary ink is determined by its colorant and its formulation.
Pontes et al., U.S. Pat. No. 5,100,469, disclose an ink composition comprising a colorant, a liquid carrier, and an additive selected from the group consisting of mesoerythritol and salts thereof, and RC(CH
2
OH)
3
and salts thereof. Pontes et al. further disclose the composition may comprise from about 1.0% to about 5.0%, by weight, humectant, and that suitable humectants include glycerol, thiodiglycols, ethylene glycol, diethylene glycol and 2-pyrrolidone. Pontes et al. teach colorants may include direct dyes, acid dyes, reactive dyes and polymeric dyes.
Hotomi et al., U.S. Pat. No. 5,376,169, disclose a recording solution for ink jetting comprising pigment, resin, an additive selected from the group consisting of alginates and bomeols, and at least 55%, by weight, of a non-aqueous solvent. Hotomi et al. further teach the non-aqueous solvent may be selected from monoethylene glycol, monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, monopropylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropyl monobutyl ether, butyl cellosolve and 2-pyrrolidone. The recording solution of Hotomi et al. may further comprise from 7% to 45%, by weight, of a compound selected from water, dithioethanol, formamide, glycerin, ethylene carbonate and methane sulfonic acid.
Gundlach et al., U.S. Pat. No, 5,531,815, disclose ink compositions comprising a betaine zwitterionic base, a quasisurfactant penetrant and, optionally, solvents such as n-methylpyrrolidione, thiodiethanol, ethylene glycol, trimethylol propane, sulfolane and glycerine.
Gundlach et al., U.S. Pat. No. 5,534,050, disclose ink compositions comprising an acetylenic polyalkylene oxide and a quasisurfactant penetrant. Gundlach et al. disclose solvents such as cyclohexyl pyrrolidione and co-solvents such as n-methylpyrrolidinone, thiodiethanol, ethylene glycol, trimethylol propane, sulfolane, and glycerine.
Nagai et al., U.S. Pat. No. 5,882,390, disclose a recording ink composition comprising a colorant which includes at least one phthalocyanine compound, a dispersant and/or surfactant, water and a humectant. Nagai et al. further disclose that humectants include water-soluble organic solvents such as diethylene glycol, thiodiethanol, polyethylene glycol, glycerol, N-methyl-2-pyrrolidinone, N-hydroxy-2-pyrrolidone, 2-pyrrolidone and 1,3-dimethylimidazolidinone.
Nagai et al., U.S. Pat. No. 5,879,439, disclose a recording ink composition comprising a colorant comprising a pigment and a polymeric dye, a dispersant and/or surfactant, water, and a water-soluble organic solvent such as diethylene glycol, thiodiethanol, polyethylene glycol, triethylene glycol, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, 3-methylpentane-1,3,5,-triol, 1,5-pentanediol, N-methyl-2-pyrrolidone, N-hydroxy ethyl-2-pyrrolidone, 2-pyrrolidone and 1,3-dimethylimidazolidinone.
Nagai et al., U.S. Pat. No. 5,810,915 disclose an aqueous ink composition including a dye component containing a water-soluble xanthene dye or a water-soluble phthalocyanine dye. Nagai et al. teach that the composition may further comprise water-soluble organic solvents such as diethylene glycol, thiodiethanol, polyethylene glycol, triethylene glycol, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, 3-methylpentane-1,3,5-triol, 1,5-pentanediol, N-methyl-2-pyrrolidone, N-hydroxy-ethyl-2-pyrrolidone, 2-pyrrolidone and 1,3-dimethylimidazolidinone.
There is a need for providing high chroma primary inks that will provide a large color gamut.
SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide pigmented ink with high chroma.
It is another object of this invention to provide pigment compositions comprising red pigment which have high chroma values.
In accordance with one aspect of the present invention, ink compositions comprise red pigment and a carrier mixture comprising a bishydroxy terminated thioether and a lactam.
In accordance with another aspect of the present invention, there is provided an ink composition comprising Pigment Red 81, 2-pyrrolidone and 2, 2′-thiodiethanol.
In accordance with another aspect of the present invention, methods of increasing the chroma of an ink composition comprising a red pigment comprise the step of adding to the ink composition a carrier mixture comprising a bishydroxy terminated thioether and a lactam.
It has now been found that a carrier mixture comprising a bishydroxy terminated thioether and a lactam can increase the cliroma of an ink containing red pigment. The high chroma ink provides for a larger color gamut.
These and additional objectives and advantages will be more fully apparent in view of the following description.
DETAILED DESCRIPTION
It has been found that it is possible to increase the chroma of an ink comprising red pigment by incorporating a carrier mixture. The carrier mixture comprises a bishydroxy terminated thioether and a lactam.
Suitable bishydroxy terminated thioethers have the formula HO-(A)-S-(A)-OH, wherein each A is independently an aryl group or a (CR
2
)
x
, wherein each R is independently a hydrogen, C
1-6
alkyl group, aryl group or halogen, and x is an integer from about 1 to about 7. A preferred bishydroxy terminated thioether is 2,2′-thiodiethanol.
Lactams are cyclic amides. Suitable lactams for use herein include five-member ring lactams such as 2-pyrrolidone, 1-methyl-2-pyrrolidone, 1-(2-hydroxyethyl)-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and mixtures thereof. Preferably the lactam is 2-pyrrolidone.
The composition comprises a red pigment. Suitable red pigments include Pigment Red 3, Pigment Red 19, Pigment Red 22, Pigment Red 23, Pigment Red 31, Pigment Red 81, Pigment Red 101, Pigment Red 112, Pigment Red 149, Pigment Red 170, Pigment Red 268, Pigment Red 269; preferably the red pigment is Pigment Red 81. The composition generally comprises from about 0.2% to about 10%, preferably from about 0.5% to about 6%, and most preferably from about 1.0% to about 5.0%, by weight of the total ink composition, red pigment.
The ink composition generally comprises, by weight, from about 5% to about 40%, preferably about 20%, total carrier mixture. The ink composition generally comprises from about 1% to about 35%, preferably from about 5% to about 15%, more preferably about 10%, by weight, bishydroxy terminated thioether, and from about 1% to about 35%, preferably from about 5% to about 15%, more preferably about 10%, by weight, lactam. The weight ratio of the bishydroxy terminated thioether to the lactam is generally from about 15:85 to about 85:15, preferably from about 45:55 to about 55:45, and more preferably about 50:50.
The composition may comprise dispersants to prevent the pigment from settling and flocculating in the ink composition. The pigment to dispersant weight ratio is generally from about 1:1 to about 6:1, preferably about 3:1. The composition may comprise from about 0.05% to about 7%, preferably from about 0. 1% to about 6%, and most preferably from about 0.2% to about 4.0%, by weight, dispersant.
Polymer dispersants stabilize pigment dispersion in aqueous ink compositions and assist in the redispersion of the pigment after drying out of the nozzle during printer shutdown. Additio
Daspit Jacqueline M.
Klemanski Helene
Lexmark International Inc.
Zurcher Jackie
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