Methods of making magenta colorants for ink systems
a colorant and magenta technology, applied in the field of rhodamine dye, can solve the problems of low-toxicity rhodamine, poor light fastness, limited use, etc., and achieve the effects of low phthalate amount, low hue error, and excellent spectral strength
Inactive Publication Date: 2002-10-10
MILLIKEN & CO
View PDF0 Cites 0 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Benefits of technology
[0016] It is an advantage of the present invention that the urethane substituted xanthene can be design engineered to obtain desired properties for specific printing platforms and architectures. It is also an advantage of the present invention that the urethane substituted xanthene is very pure, being free of salts and other insoluble contaminants. It is another advantage of the present invention that the urethane substituted xanthene can be used in combination with other phase change ink carrier materials to obtain ink compositions that possess excellent spectral strengths. It is still another advantage of the present invention that the urethane substituted xanthene are substantially transparent. It is yet another advantage of the present invention that the urethane substituted xanthene provide close to true magenta shades with low hue error and grayness. These and other aspects, features and advantages are obtained by the use of urethane substituted xanthenes that are the reaction products of urethane substituted aminophenol with phthalic anhydride that are suitable for use with waxes and / or oils in phase change ink jet inks and offset inks that may be employed in direct or indirect printing applications.
[0017] It has been found that even though the reaction of isocyanates with oxyalkylenated aminophenol compounds results in the formation of oxyalkylene groups on the phenolic hydroxyl group, the subsequent reaction of the urethane substituted aminophenol with phthalic anhydride proceeds very well producing a xanthene colorant free of phthalates, pure and completely compatible in wax and / or oil systems conforming with the Formula (II) 4
[0018] wherein x+y is greater than 0 and less than 4; wherein R is selected from the group consisting of hydrogen, halo, formyl, C.sub.1-C.sub.20 alkoxy, and C.sub.1-C.sub.20 alkyl; wherein R' is selected from the group consisting of C.sub.1-C.sub.10 alkoxy, C.sub.1-C.sub.10 polyoxyalkoxy, C.sub.1-C.sub.10 alkylester, and C.sub.1-C.sub.10 alkyl; and wherein R'" is selected from the group consisting of hydrogen and C.sub.1-C.sub.4 alkyl groups; and wherein R'" is selected from the group selected from hydrogen and C.sub.24 alkyl groups; or any salts thereof.
[0019] The standard reactions followed in the past to attach oxyalkylene groups to amino or hydroxyl pendant groups have included reactions with ethylene oxide without any base present. The resultant reactions thus quickly drive the addition of the oxyalkylene groups to the undesired phenolic hydroxyl sites, and ends up preventing the desired reaction with phthalic anhydride to form a xanthene. In the inventive method, the urethane linkage, presumably, breaks in a reversible reaction, thus allowing the reaction with phthalic anhydride to proceed and form the xanthene colorant. This reaction appears to work with any aminophenol compound, although highly preferred is a m-aminophenol base compound with extra pendant groups selected from the group consisting of hydrogen, halo, C.sub.1-C.sub.20 alkoxy, and C.sub.1-C.sub.20 alkyl. Again, in each instance, the 1 to 3 moles of, for instance, propylene oxide (per m-aminophenol compound) when directly reacted with the starting aminophenol reactant at a suitable relatively low temperature, will only attack the amino groups, thereby producing an oxypropyl-substituted aminophenol having at most an average of 1.5 monomers (i.e., 2 monomers on one site and 1 monomer on the other) of propylene oxide added per carbon-nitrogen bond of the amino moiety. Such an intermediate is represented by Formula (I), above, and can thus be reacted with at least one other reactant compound to form any number of different colorants. For instance, this intermediate may also be reacted benzaldehyde (preferably one with carboxylic or sulfonate groups attached, such as benzaldehyde-2,4-disulfonic acid), as taught within the Barry, Jr. patent., as well as through the reaction of other compounds, such as, as merely an example, o-formyl-benzenesulfonic acid. Furthermore, the inventive intermediate will not alternatively form the correlative xanthene dyestuff during the reaction with phthalic anhydride. Such a dyestuff is highly regulated and poses potential toxicity problems and thus it is desirable to avoid production of such a compound. Furthermore, the dyestuff cannot be modified physically and / or chemically since there are no remaining reactive sites at which electrophilic groups may be attached. The inventive method and the inventive intermediate therefore provide clear distinct advantages over the previously disclosed xanthene compounds production methods. Additionally, the inventive intermediate can be reacted with other reactant compounds to form other types of colorants. For example, an oxazine colorant may be formed by nitrosating one mole of the inventive intermediate and subsequently reacting that reactant compound with a second mole of the inventive intermediate. Furthermore, other colorants may also be formed, such as coumarins, through the reaction of the inventive intermediate with other reactant compounds such as, without limitation, ethylcyanoacetate and phenylenediamine.
[0020] As noted above, such novel intermediates permit production of colorants made therefrom (particularly xanthenes) that are substantially phthalate-free through the initial reaction of the isocyanate constituent with the free hydroxyls during reaction with phthalic anhydride. A low amount of phthalate may be produced on the final colorant product; however, such an amount is drastically reduced in comparison with the previously followed production methods without isocyanate-capped hydroxyl moieties. Thus, the amount of phthalate produced by the inventive method and thus found on the target xanthene colorant is below about five (5) molar percent in total. Such an amount is thus the definition of the term "substantially phthalate-free" as well.
[0021] Such inventive substantially phthalate-free colorants may be utilized in any number of coloring procedures, including ink, paint, print, dye, tint, and the like, applications. Thus, compositions utilized to provide colorations to various substrates, including, without limitation, cellulose-based substrates (paper, cotton fabrics, and the like), magazine-paper substrates, and the like, are preferred surfaces for coloring. Other surfaces, substrates, etc., may be contacted with the inventive colorants as well. Most preferably, however, such colorants are to be utilized in ink applications, most notably inkjet, lithographic, and offset ink operations. Offset applications are basically newsprint, magazine-print, and like types, of printing procedures. In such operations, it is important to provide long-term stability of the target ink solution solubility of the colorant in the ink compositions and water resistance of the printed image from the ink composition. For inkjet inks, particularly wax-based types, heat stability of the entire ink system is of paramount importance, since the printing process comprises numerous periods of heating and cooling cycles in order for the inks to perform the desired print operation. Thus, such inks must be able to retain their color strength upon evaluation of exposure at 150.degree. C. for prolonged and / or intermittent periods (e.g., 30 minutes or 5 minutes heated, 5 minutes cooled, 5 minutes heated, and so on, as merely examples). The color difference between an initial print and an oven-aged print is calculated using the following equation:.DELTA.E*=((L.sup.*.sub.initial-L.sup.*.sub.aged).sup.2+(a.sup.*.sub.initi-al=a.sup.*.sub.aged).sup.2+(b.sup.*.sub.initial-b.sup.*.sub.aged).sup.2).s-up.1 / 2
Problems solved by technology
While such dyes have been utilized within certain portions of the colorant industry, their use has been limited due to toxicity issues.
Thus, they are generally unsuitable for use when human exposure to such a dye is likely.
However, such a low-toxicity rhodamine exhibits relatively poor light fastness, as well as poor solubility in non polar media.
However, the intermediates used in a typical rhodamine synthesis may not be readily alkoxylated without adding poly(oxylakylene) to sites on the intermediate which participate in colorant formation.
However, the reaction of these electrophiles is limited to the availability of the free hydroxyl groups in the oxyalkylenated xanthene, as some of the hydroxyl groups react with the phthalic anhydride to form phthalates during the formation of the xanthene colorant.
The presence of phthalates, however, in these urethane substituted xanthene colorants reduces the compatibility of these colorants in such wax based ink systems.
Again, however, phthalates present within the urethane substituted xanthene colorants remain insoluble in these diluents, thus making these colorants unsuitable for use in these applications.
Thus, even though poly(oxyalkylenated) xanthene colorants have only recently been made available to the colorant market, the utilization of such colorants, particularly made from the intermediate disclosed within the '482 patent, the use of such colorants has still been limited due to the lack of complete compatibility in wax and / or oil based systems due to the formation of the aforementioned deleteroius phthalates (through the reaction of phthalic anhydride on the free hydroxyls groups of the polyoxyalkylene moieties).
To date, the prior art has not accorded such an improvement within this specific area of colorant chemistry.
Because of this lack of such a specific type of colorant, the versatility and widespread use of such colorants in different types of inks and substrate has not been accomplished.
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
example 2
[0030] 193 parts of the polyoxyalkylene substituted aminophenol intermediate precursor of Formula (A) 6
[0031] (from U.S. Pat. No. 5,250,708) were charged into a reactor vessel with 168 parts of n-butyl isocyanate, and 13.4 parts of dibutyltindilaurate catalyst. The mixture was heated with stirring to 70.degree. C. under a N.sub.2 atmosphere. After 4.0 hours at 70 C an FT-IR spectrum of the product was obtained to insure all isocyanate functionality is consumed. The absence (disappearance) of a peak at about 2275 cm.sup.-1 (NCO) and the appearance (or increase in magnitude) of peaks at about 1740-1680 cm.sup.-1 and about 1540-1530 cm.sup.-1 corresponding to urethane frequencies, thereby confirm the conversion of the isocyanate to the urethane.
[0032] Colorant Production
[0033] The general methods of making the preferred inventive colorants are as follows:
example 3
[0034] 700 parts of the intermediate produced in Example-1 was charged into a flask containing 399 parts of phthalic anhydride, 41.6 parts of 93% sulfuric acid, and 832 parts of toluene (solvent). The reactants were then heated up to 100.degree. C. and maintained at a temperature from about 100 to 105.degree. C., until the 340 nm peak, representing the inventive intermediate, in the uv / vis spectrum has disappeared and the color value, measured as absorbance (550 nm) per gram per liter, representing the target xanthene colorant stops to increase in magnitude (through measurement by a uv / vis spectrophotometer). The product was washed with deionized water and filtered and the toluene was removed by the azeatrope with water to yield the urethane substituted xanthene, leaving a compound exhibiting a brilliant magenta hue and represented by Formula (II) 7
[0035] wherein R'" is octadecenyl, R" is methyl, R' is hydrogen, X is HSO.sub.4.sup.-, and x=y=1 (thus x+y=2.
[0036] Ink Applicat...
example 4
Wax Based Inks
[0037] 20 parts of the xanthene colorant produced in Example 3 was mixed with a color stick from Xerox for a Phaser 850 printer under heat (120-150.degree. C). The product was allowed to mix well while hot and poured into an aluminum dish. This mixture was subjected to several heating and cooling cycles to determine compatibility through these cycles. The product appeared to be completely compatible with the wax systems throughout the heating / cooling cycles. After contacting with paper, the colorant exhibiting .DELTA.E* well below 1.5 in accordance with the oven aging test described above.
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
| Property | Measurement | Unit |
|---|---|---|
| temperature | aaaaa | aaaaa |
| temperature | aaaaa | aaaaa |
| temperature | aaaaa | aaaaa |
Login to View More
Abstract
Novel addition products of isocyanates with oxyalkylene-substituted aminophenol compounds as intermediates for the production of urethane-substituted xanthene colorants, particularly triphenylmethane derivatives such as rhodamines, are provided. The xanthene colorants exhibit improved wax and / or oil solubility and high purity. The urethane-substituted xanthene colorant features very good wax and / or oil solubility, and is believed to be relatively nontoxic. A method for producing this novel colorant is also provided.
Description
[0001] This invention relates to novel addition products of isocyanates with oxyalkylene-substituted aminophenol compounds as intermediates for the production of urethane-substituted xanthene colorants, particularly triphenylmethane derivatives such as rhodamines. The xanthene colorants exhibit improved wax and / or oil solubility and high purity. The urethane-substituted xanthene colorant features very good wax and / or oil solubility, and is believed to be relatively nontoxic. A method for producing this novel colorant is also provided.BACKGROUND OF THE PRIOR ART[0002] All U.S. and foreign patents cited within this specification are hereby incorporated by reference.[0003] Xanthene dyes, and in particular rhodamine dyes, are well known in the art as exemplified in the COLOUR INDEX, 3rd. ed., Vol. 4, pp. 4419-4422 (1971). These dyes range from bright red to bright bluish red, and typically fluoresce orange or red upon exposure to ultraviolet light. Most importantly, such rhodamines prov...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & AuthorityApplications(United States)
IPC IPC(8): C07D311/88C09B69/10
CPCC09B69/103C07D311/88
InventorBATLAW, RAJNISHMOORE, PATRICK D.
OwnerMILLIKEN & CO