Toner compounds and compositions for black offset inks

Details Toner compounds and compositions for black offset inks Toner compounds and compositions for black offset inks

2001-10-26

2003-12-16

Shosho, Callie (Department: 1714)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Processes of preparing a desired or intentional composition...

C524S589000, C524S590000

Reexamination Certificate

active

06664311

ABSTRACT:

FIELD OF THE INVENTION
A novel colorant compound is provided which is the addition product of an organic chromophore having at least one reactive hydroxyl or amine substituent, a mono or polyisocyanate, and/or an alcohol. Such a compound provides solubility in oil-based ink compositions, complete water resistance and excellent oil based ink compositions. Furthermore, such colorants provide an easy and efficient way to tone shades of oil based inks. In addition, such colorants provide a way to tone carbon black based lithographic inks that gives these inks the appearance of being jet black on various types of printing substrates. A method for producing such a colorant is also provided, as well as offset ink compositions comprising such a colorant (including other colorants that provide the same toner performance within black pigment formulations).
BACKGROUND OF THE PRIOR ART
All U.S. and foreign patents cited within this specification are hereby incorporated by reference. The nature of the Offset printing process imposes certain fundamental requirements on the chemical, physical and strength characteristics of its inks. Toners are necessary to provide jet black appearances of images containing standard black pigments, such the, carbon black. Such a toner must be compatible in Offset ink vehicles, must not produce unacceptably high viscosity even at high loadings, and must be fundamentally insoluble in, and unreactive with the aqueous/alcohol fountain solution. Currently, alkali blue is utilized as the most prevalent black pigment toner in offset ink operations. Unfortunately, although such a toner meets the required solubility properties, the toning effects provided thereby simultaneously are less than satisfactory due to an excessive reddening and/or bronzing of the black printed image. An improved toner reducing such unwanted effects is thus highly desired within the black offset ink industry and market. To date, there are no teachings or fair suggestions of such needed improvements provided by and within the pigment for Offset inks prior art. It is believed that certain chromophores with an appropriate pendant group system may not only provide such desired aqueous/alcohol fountain insolubility, but may also provide effective toning with low-reddening and low-bronzing levels within such black offset inks.
Examples of colorants having substituent groups intended to tailor the properties of the colorant may be found in the following references. Batlaw et al., U.S. Pat. No. 5,919,846 disclose a compound which is the addition product of a chromophore and an isocyanate, wherein the isocyanate has a carboxyl containing group bonded thereto. The compound may be incorporated in a composition useful for printing on or dyeing a substrate. Moore et al., U.S. Pat. No. 5,176,745, disclose a poly(oxyalkylene) substituted colorant reacted with a cyclic anhydride such as an alkenyl succinic anhydride, providing a free carboxyl group. The colorant may be made water-soluble by adding a suitable counter ion. Sharma et al., U.S. Pat. No. 5,637,637, disclose a waterborne copolymeric colorant composition prepared by emulsion polymerization of a dye having a reactive vinyl group and a vinyl monomer, such as styrene.
A colorant compound having polymer or pre-polymer substituent groups may be synthesized by the reaction of a colorant and a polyisocyanate as disclosed in Cross et al., U.S. Pat. No. 4,284,729; Krutak et al., U.S. Pat. No. 5,194,463; and Beckmann et al., U.S. Pat. No. 5,616,678.
Ink compositions containing polyurethane substituted colorants have been disclosed. Chandler et al., U.S. Pat. No. 5,637,638, provide a waterborne polyurethane-urea derived colorant intended to be easily erasable from a cellulosic substrate such as paper. Tektronix, Inc., EP 0 769 509 A, disclose a non-erasable ink jet composition containing a colored polyurethane dispersion formed by the resin of at least one polyol, at least one polyisocyanate, at least one internal surfactant and at least one reactive colorant. The dispersion contains particles ranging in size from 0.01 to 5.0 microns.
Alkali Blue pigment and the rhodamine pigment have been used as toners in oil-based inks. Alkali Blue pigment is well known in the art as Pigment Blue 61 (Colour Index # 42765:1). Such a toner component is disclosed within U.S. Pat. No. 5,026,627 which teaches a particular combination of surfactants when incorporated with an alkali blue pigment, which then produce a pigment toner exhibiting high strength when used in oil-based inks. While such a pigment is widely used throughout the industry, it exhibits serious drawbacks in that it is difficult to handle, is not conducive to post-addition, creates a reddish tone to carbon black inks, and causes bronzing of the resultant printed image.
U.S. Pat. Nos. 5,919,846, 5,919,839, and PCT Patent Application WO 94/14902 describes the reaction of hydroxyl containing colorants with mono and diisocyanates.
SUMMARY OF THE INVENTION
Therefore, one of the objects of the invention is to provide an oil soluble colorant. Another object of this invention is to provide a synthetic route for a polymeric colorant wherein the colorant is substantially soluble in hydrocarbon oil-based inks and is substantially insoluble in water. Still another object of the invention is to provide a colorant that can be used as a toner for oil based inks. Yet another object of the invention is to provide a colorant that can tone carbon black based inks to give a jet black image. Yet another object of the invention is to provide a colorant that can tone carbon black based inks to give a glossier image. Yet another object of the invention is to provide a colorant that can tone carbon black based inks to give an image with substantially reduced bronzing. Yet another object of the invention is to provide a colorant that can tone carbon black based inks and that is easy to handle. Yet another object of the invention is to provide a colorant that can tone carbon black based inks at any stage of the ink manufacturing process.
Accordingly, this invention encompasses a compound comprising the addition product of (a) an organic chromophore having at least one reactive hydroxyl or amine substituent group; (b) a mono or polyisocyanate; and (c) a long chain alcohol wherein said monoisocyanate reacts with said reactive hydroxyl or amine substituent groups to form a urethane colorant; wherein said polyisocyanate reacts with each of said reactive hydroxyl or amine substituent groups to form isocyanate terminal groups on said organic chromophore and, subsequently, said long chain alcohols reacts with said isocyanate terminal groups to form urethane or urea moieties on the resulting compound. More specifically, this invention encompasses a compound conforming to the structure of Formula (I):
wherein A is a chromophore, B is a linking group selected from the group consisting of N, NR, O, S, SO
2
, SO
2
N, SO
2
NR, CO
2
, CON and CONR, Q is selected from the group consisting of C
2
-C
18
alkyleneoxy and any combinations thereof, x is from 0 to 200, y is 0 or 1, Z is selected from the group consisting of aliphatic residues and aromatic residues, R′ is C
4
-C
30
alkyl, a is 1 or 2, b is 1-5, and R is C
1
-C
12
alkyl. Preferably, A is a group exhibiting one of the following chromophoric backbones selected from the group consisting of such backbones as nitroso, nitro, azo, diarylmethane, triarylmethane, xanthene, acridine, quinoline, methine, thiazole, indamine, indophenol, lactone, aminoketone, hydroxyketone, stilbene, azine, oxazine, thiazine, anthraquinone, phthalocyanine or indigoid. Preferably, such a chromophore is a triphenylmethane, azo, methine, and anthraquinone. Preferably, such a colorant may be defined alternatively as comprising a chromophore that provides &lgr;
max
absorption measurements between about 550 and 610 nm (wavelengths), most preferably wavelengths between about 560 and 580 nm. Preferably, B is N (and thus a is 2), or O (and thus a is 1), Q is a combination of ethyleneoxy and propyleneoxy with from ab

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