JP2009540051A - Carbonyl self-dispersing pigment and inkjet ink containing the pigment - Google Patents

Abstract

  Disclosed are pigments having a covalently bonded stabilizing group that enables the formation of a stable dispersion of the pigment in a liquid and a covalently bonded chemical species containing at least one externally reactive carbonyl group. Such pigments are particularly useful in reactive inkjet ink formulations.

Description

  The present invention relates generally to self-dispersing pigments and their use in inkjet inks. More particularly, the present invention relates to a self-dispersing pigment having a covalently bonded stabilizing group and further at least one covalently bonded externally reactive carbonyl group that enables the formation of a stable dispersion of the pigment in a liquid. This pigment is particularly useful in reactive inkjet ink formulations.

CROSS REFERENCE TO RELATED APPLICATIONS This application claims priority from US Provisional Patent Application No. 60 / 810,937, filed June 5, 2006. The disclosure of this patent application is incorporated herein by reference in its entirety for all purposes as if fully set forth herein.

  Inkjet printing is a non-impact printing method in which droplets of ink are deposited on various media to form a desired image. The droplets are ejected from the print head in response to an electrical signal generated by the microprocessor. The ink used is subject to strict requirements including, for example, good dispersion stability, ejection stability and good fixing to the media.

  Inkjet printers provide high quality printing at low cost and have become a common replacement for other types of printers such as laser printers. However, inkjet printers cannot match the speed of laser printers and the durability of laser printed images. An ink jet print having high durability would be very advantageous.

  The use of a reactive ink jet ink set comprising at least two inks can increase the durability of the ink jet print. The first ink contains a chemical species having at least one reactive carbonyl group, and the second ink contains a chemical species having at least one reactive amine group.

  The advantages of such a reactive ink set are fully described in US Patent Publication (Patent Document 1) (filed March 9, 2006), when two inks are printed on a substrate in an overlapping state. It is possible to achieve the best. Thus, both types of reactive species are in close proximity on the substrate and crosslinking can occur easily, thereby increasing the durability of the print. Ink printing can occur in any order or simultaneously. It may be advantageous to heat the printed substrate in order to promote the cross-linking reaction between the reactive carbonyl group and the reactive amine group. Useful temperatures for this purpose are typically from about 60 ° C to about 150 ° C.

  New chemicals are still needed to expand the selection of reactive species that are compatible and stable and can be easily introduced into reactive ink sets to optimize performance. Accordingly, there is a need for reactive carbonyl group-containing self-dispersing pigments suitable for ink jet printing, and the object of the present invention is to provide such pigments.

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Tsubokawa, Prog. Polym. Sci, 17, 417-470 (1992) Bull. Chem. Soc. Jpn. 75, 2115-2136 (2002) Howell and Liu, Thermochimica Acta, 243 (1994), 169-192. Wang et al., Dyes and Pigments, 41 (1999), pages 35-39. Tetrahedron, 36, 1753 (1980) Tetrahedron Letters, 28, 4255-4258, 1987 Tsubokawa, Reactive and Functional Polymers, 27, 75-81 (1995) M.M. M. Kunishima, Tetrahedron, 57, 1551-1558 (2002)

  In one aspect, the invention provides (a) a covalently bonded stabilizing group that allows the formation of a stable dispersion of the pigment in the liquid and (b) a covalently bonded group containing at least one externally reactive carbonyl group. The present invention relates to a self-dispersing pigment containing pigment particles having chemical species.

  The present invention includes a liquid vehicle and a pigment, wherein the pigment contains a covalently bonded stabilizing group that enables the formation of a stable dispersion of the pigment in the liquid and at least one external reactive carbonyl group. There is further provided an inkjet ink comprising pigment particles having bound chemical species.

The present invention is an inkjet ink set including at least a first ink and a second ink,
(A) the first ink comprises a liquid vehicle and a pigment, the pigment comprising a covalently bonded stabilizing group that enables formation of a stable dispersion of the pigment in the liquid, and at least one external reactive carbonyl group A pigment particle having a covalently bound chemical species containing
(B) An inkjet ink set is also provided in which the second ink comprises a liquid vehicle and a chemical species having at least one reactive amine group.

Examples of seven synthetic routes that can be used to produce carbonyl group-containing self-dispersing carbon black particles or organic pigment particles useful in the practice of the present invention are shown in the figure (the resulting pigment particles are each represented by particle 11). ~ 17). 2 shows the preparation of a diazotized precursor used in the reaction for producing the carbonyl self-dispersing pigment particles 11 of FIG. FIG. 2 illustrates the preparation of a diazotization precursor used in the reaction to produce the carbonyl self-dispersing pigment particles 12 of FIG. 1 and an alternative alkylating reagent for preparing analogs of the carbonyl self-dispersing pigment particles 12. 2 shows the preparation of an amine precursor used in the reaction to produce the carbonyl self-dispersing pigment particles 13 of FIG. 2 illustrates the preparation of a beta ketoamide precursor used in the reaction to produce the carbonyl self-dispersing pigment particles 15 and 16 of FIG. 2 shows the preparation of a diketone precursor used in the reaction to produce the carbonyl self-dispersing pigment particles 17 of FIG. 3 illustrates three additional synthetic routes that can be used to form carbonyl self-dispersing carbon black or organic pigment particles useful in the practice of the present invention. 3 shows examples of three other reactions that produce carbonyl self-dispersing carbon black or organic pigment particles useful in the practice of this invention. 2 shows examples of two further reactions that can be used to produce carbonyl self-dispersing carbon black or organic pigment particles useful in the practice of this invention by attaching a carbonyl group to the D group. 2 illustrates another example synthetic route to carbonyl self-dispersing carbon blacks or organic pigments useful in the practice of this invention. 3 illustrates an example of a synthetic route for producing carbonyl self-dispersing inorganic pigments useful in the practice of the present invention. 3 illustrates an example of a synthetic route for producing carbonyl self-dispersing inorganic pigments useful in the practice of the present invention.

  The present invention relates to a carbonyl self-dispersing pigment, i.e. a covalently bonded chemistry containing a covalently stabilizing group that enables the formation of a stable dispersion of the pigment in a liquid and at least one externally reactive carbonyl group. A pigment having pigment particles containing a seed is provided. The pigment particles contain a sufficient number of covalently bonded stabilizing groups to allow the formation of a stable dispersion of the pigment in the liquid and contain at least one covalently linked external reactive carbonyl group. contains. Preferably, the pigment particles contain two or more externally reactive carbonyl groups. Carbonyl self-dispersing pigments are particularly useful in ink jet set inks when another ink in the ink set contains a chemical species having a reactive amine group.

  As commonly understood in the art and used herein, the term “self-dispersing” refers to pigment particles such that the pigment particles form a stable dispersion in a liquid in the absence of any other dispersant. Means a pigment having a stabilizing group covalently bonded to the surface. Covalently stabilizing groups that enable the formation of a stable dispersion of pigment in a liquid are referred to herein as “D” groups, ie, dispersible groups.

  According to the present invention, a reactive carbonyl group is also provided in the novel self-dispersing pigment so that the novel self-dispersing pigment can participate in the desired crosslinking reaction. In general, reactive carbonyl groups that are effective in cross-linking are not effective in dispersion, and thus the covalently bonded dispersive groups and covalently bonded reactive carbonyl groups on the self-dispersing pigment are typically distinct and different. It is a chemical species. While self-dispersing pigments having covalently bonded dispersive groups are well known in the art, self-dispersing pigments having both covalently bonded dispersible groups and reactive carbonyl groups are novel and unique.

  The carbonyl group is: a) the carbonyl group is not part of the pigment molecular formula, but is bonded to only the pigment molecule on the surface of the pigment particle, b) the carbonyl group is covalently bonded to the external end, ie, the pigment particle. It is an “external” group in the sense that it is a terminal group at the terminal that is not covalently bonded to the pigment particles of the entity. A carbonyl group is called “reactive” because it can react with a reactive amine group, ie, can be cross-linked by a reactive amine group. The reactivity of these carbonyl groups is enhanced as a result of the position of the carbonyl group at the external end of the entity that is covalently bound to the pigment particle. Various alkyl or aryl groups or hydrogen can be attached to the carbonyl group to form a ketone or aldehyde. The reactivity of the carbonyl group is expected to be highest when a methyl group or hydrogen is attached to the carbonyl group. The chemical species containing the external reactive carbonyl group can be covalently bonded directly to the pigment particle, can be bonded to other groups that are covalently bonded to the pigment particle, or the pigment particle It can be added to a polymer chain that is covalently bonded to.

  The pigment particles can be carbon black particles, organic colored pigment particles or inorganic pigment particles. Typical commercial pigments in dry form include the following pigments:

  Representative commercial pigments available in the form of a water-wet presscake include “Heucophthal” ® Blue BT-585-P, “Toluidine” Red Y (C.I. Pigment Red 3), “Quindo” ® Magenta (Pigment Red 122), “Magenta” RV-6831 press cake (Mobay Chemical, Harmon Division, Haredon, NJ), Mobay Chemical, Harmon Division (Haledon, NJ))), “Sunfast” RTM Magenta 122 (Sun Chemical Corp. (Cin), Cincinnati, Ohio. innati, OH))), "India (Indo)" (registered trademark) Brilliant Scarlet (Pigment Red 123), C. I. No. 71145), “Toluidine” Red B (CI Pigment Red 3), “Watchung” (registered trademark) Red B (CI Pigment Red 48), “Permanent Rubin” F6B13-1731 (Pigment Red 184), "Hansa" (registered trademark) Yellow (Pigment Yellow 98), "Dalamar" (registered trademark) Yellow YT-893-P (Pigment Yellow 74, C.I.). I. No. 11741), “Sunbrite” (registered trademark) Yellow 17 (Sun Chemical Corp. (Cincinnati, Ohio)) "Toluidine Yellow G (CI Pigment Yellow 1), Pigment Scarlet (CI Pigment Red 60), Auric Brown (CI Pigment Brown 6), etc. Black pigments are generally not available in the form of aqueous press cakes.

  The liquid vehicle carrier of the inkjet ink can be aqueous or organic.

  The term “aqueous liquid” or “aqueous vehicle” means water or a mixture of water and at least one water-soluble organic solvent (co-solvent). The selection of a suitable mixture depends on the requirements of the particular application such as the desired surface tension and viscosity, the selected colorant, the drying time of the ink and the type of substrate on which the ink is printed. When using a mixture of water and a water-soluble solvent, the aqueous vehicle typically contains about 30% to about 95% water, with the remainder (ie, about 70% to about 5%) being a water-soluble solvent. . Preferred compositions contain about 60% to about 95% water, based on the total weight of the aqueous vehicle.

  “Organic liquid” or “organic vehicle” means a liquid or vehicle that is substantially non-aqueous and consists of an organic solvent or mixture of organic solvents. These solvents can be polar and / or nonpolar. Examples of polar solvents include alcohols, esters, ketones and ethers, particularly glycols such as monopropylene glycol, monomethyl ether of dipropylene glycol and tripropylene glycol, and mono-n-butyl ether of ethylene glycol, diethylene glycol and triethylene glycol And monoalkyl ethers and dialkyl ethers of polyglycols. Examples of non-polar solvents include aliphatic and aromatic hydrocarbons having at least 6 carbon atoms, and mixtures thereof including refinery distillation products and refinery distillation by-products. Even when water is not deliberately added to the organic vehicle, some accidental water can be carried into the formulation, but generally this is no more than about 2-4%. As used herein, an organic vehicle has no more than about 10% by weight of water, preferably no more than about 5% by weight, based on the total weight of the non-aqueous vehicle.

  A number of methods have been disclosed for stabilizing pigments in aqueous or organic vehicles, ie, functionalizing pigments with covalently stabilizing groups that render the particles self-dispersible. Covalent stabilizing groups for aqueous liquids are carboxylate, amine, sulfonate, sulfinate, phosphate, amine, quaternized amine or ethoxylate oligomer groups or covalently bonded polymers containing these stabilizing groups. It is possible that there is.

  These covalently bonded groups remain as prepared, or neutralize the acidic group with a base to form an anion, or neutralize the basic group with an acid to form a cation to form pigment particles. It must be present in an amount sufficient to make it possible to form a stable dispersion.

  It is possible to stabilize inorganic oxide particles to form dispersions by adsorbed cations or anions, or by covalent anionic groups or covalent cationic groups for aqueous liquids, or organic liquids It is possible to stabilize the inorganic oxide particles so that they can be dispersed therein. Covalent stabilizing groups as used herein include not only covalently bound anionic groups or covalently cationic groups, but also their adsorbed cations or anions.

  For organic liquids, covalently bonded stabilizing groups that are compatible with the organic liquid are used. The stabilizing group in the organic liquid can also be an organic solvent compatible salt of a bound acid group or basic group.

  Self-dispersing carbon black particle dispersions stabilized by carboxylate groups formed by oxidation of the surface of the particles are disclosed in many patents. Self-dispersing carbon black prepared by ozonation and pulverization of carbon black in a media mill is disclosed in US Pat. Methods for preparing carbon black dispersions by treatment of carbon black with ultrasonic energy and hydrogen peroxide or with heat and monopersulfate are disclosed in US Pat. Is disclosed. In a series of patents, US Patent Publication (Patent Document 5), US Patent Publication (Patent Document 6), US Patent Publication (Patent Document 7), US Patent Publication (Patent Document 8) and US Patent Publication (Patent Document 9) The preparation of a stable dispersion using a low-oxidation rock salt reagent to oxidize carbon black is disclosed.

US Patent Publication (Patent Document 10) discloses surface modification of carbon particles and formation of a stable aqueous dispersion by reaction of carbon particles with a cyclic aldehyde and an AlCl ₃ catalyst.

  US Patent Publication (Patent Document 11) discloses surface modification of carbon particles with a reagent containing a double bond and a triple bond activated by a carbonyl group, for example, maleic anhydride. Using this chemistry, it is possible to covalently bond to the particles various groups that can stabilize the particles in an aqueous environment (anionic and cationic groups) or in an organic environment.

  US Patent Publication (Patent Document 12) describes functionalization of carbon particles with carboxylates, sulfonates, amines or quaternary groups for dispersion stability in an aqueous environment or organic groups that stabilize the dispersion of particles in an organic environment. A reaction of an organic compound of the general formula and carbon particles for conversion is disclosed.

US Patent Publication (Patent Document 13) describes a general formula R ¹ —N═N—R ² (wherein R is not substituted or is an acceptor) that can make carbon particles into a stable aqueous dispersion. Carbon particles reacted with compounds of which are aryl groups substituted with substituents or donor substituents are described.

US Patent Publication (Patent Document 14) discloses carbon modified with an organic group bonded via a sulfide linkage or a polysulfide linkage by reaction of a compound of the general formula R ¹ —S _x —R ² with carbon black particles. Black particles are described.

  US Patent Publication (Patent Document 15), US Patent Publication (Patent Document 16), US Patent Publication (Patent Document 17), US Patent Publication (Patent Document 18), US Patent Publication (Patent Document 19), US Patent Publication (Patent Document) Document 20) and US Patent Publication (Patent Document 21) disclose a method of bonding an organic stabilizing group to carbon black via a diazonium reaction in which the organic stabilizing group is part of a diazonium salt. Stabilizing groups include carboxylates, sulfonates, amines and quaternary amines that stabilize the dispersion of the particles in an aqueous medium and organic groups that stabilize the particles in an organic medium. US Patent Publication (Patent Document 22), US Patent Publication (Patent Document 23) and US Patent Publication (Patent Document 24) describe similar methods for attaching a stabilizing group to a colored organic pigment. U.S. Patent Publication (Patent Document 25), U.S. Patent Publication (Patent Document 26) and U.S. Patent Publication (Patent Document 27) include non-ionic stabilizing groups (and optionally a stabilizing group for pigments in organic or aqueous vehicles) Carbon blacks functionalized with diazonium salts containing ionic groups) are described.

  Carbon black particles can be modified by the addition of radical-containing groups that stabilize the dispersion of the particles in an aqueous or organic vehicle. Such dispersions can be suitable for inkjet. (Patent Document 28) includes a general formula (X) (Y) (CN) CN = NC (CN) (Y) (X) (wherein X and Y are a hydrophobic group or a hydrophilic group). Carbon black functionalized with an azonitrile compound (which is a substituent which can contain). An example of a preferred radical forming reagent with a hydrophilic group is 4,4'-azobis (4-cyanopentanecarboxylic acid).

(Patent Document 29) includes a general formula A ₁ —O—N═N—O—A ₂ (wherein A ₁ and A ₂ are the same or can contain a hydrophilic group or a hydrophobic group, or Carbon particles functionalized with hyponitrile esters (which are different substituted linear, branched or cyclic hydrocarbon groups) are disclosed.

(Patent Document 30) includes a general formula A ₁ —N═NA ₂ , wherein A ₁ and A ₂ are the same or different substituted, which may contain a hydrophilic group or a hydrophobic group. Carbon particles functionalized with azo compounds (which are linear, branched or cyclic hydrocarbon groups) are disclosed. Examples of the azo radical forming compound that imparts aqueous dispersibility include the following.

(Patent Document 31) includes a general formula A ₁ —O (O═) C—O—O—C (═O) O—A ₂ (wherein A ₁ and A ₂ are a hydrophilic group or a hydrophobic group). Carbon particles functionalized with peroxydicarbonate compounds (the same or different substituted linear, branched or cyclic hydrocarbon groups which can contain groups) are described.

(Patent Document 32) includes a general formula A ₁ —O—O—H (wherein A ₁ can contain a hydrophilic group or a hydrophobic group, substituted linear, branched or cyclic) Carbon particles functionalized with a hydroperoxide compound (which is a hydrocarbon group of

(Patent Document 33) includes a general formula A ₁ (O =) C—O—O—A ₂ (wherein A ₁ and A ₂ can contain a hydrophilic group or a hydrophobic group, the same Carbon particles functionalized with peroxyester compounds (which are or differently substituted linear, branched or cyclic hydrocarbon groups) are described.

(Patent Document 34) includes a general formula A ₁ —O—O—A ₂ , wherein A ₁ and A ₂ can contain hydrophilic groups or hydrophobic groups, different substituted linear forms. Carbon particles functionalized with peroxyester compounds (which are branched or cyclic hydrocarbon groups) are described.

(Patent Document 34) includes a general formula A ₁ —C (O═) —O—O—C (O═) —A ₂ (wherein A ₁ and A ₂ represent a hydrophilic group or a hydrophobic group). Carbon particles functionalized with diacyl peroxides, which are different substituted linear, branched or cyclic hydrocarbon groups, which can be contained are described.

  Stabilization of carbon black by surface grafting of polymers has been extensively investigated by (Non-patent Document 1) and (Non-patent Document 2). Of the three major methods of grafting, termination of the growing polymer chain onto the carbon black surface provided the lowest percentage of grafted chain. Grafting with initiating groups attached to the surface of the carbon black particles and the reaction of preformed polymers and oligomers containing functional groups with functional groups already attached to the carbon surface provide good results.

  The preparation of self-dispersing pigments for use in ink jet applications incorporating covalently bonded polymers is described in US Pat. The preparation starts with a pigment modified for water dispersibility, to which groups having vinyl unsaturation are attached. A wide range of monomers has been disclosed for grafting to these unsaturated sites to form polymer chains.

  Carbonyl self-dispersing organic pigments and carbonyl self-dispersing carbon black pigments can be prepared in various ways. Chemical species containing at least one externally reactive carbonyl group can be covalently bonded to self-dispersing pigment particles suitable for inkjet ink applications. Adding a stabilizing group prior to covalently attaching a species containing at least one externally reactive carbonyl group ensures and ensures proper pigment particle size prior to the addition of the carbonyl group. May be advantageous in that it is possible. Alternatively, a chemical species containing a stabilizing group and at least one external reactive carbonyl group can be covalently bound to the pigment particles in a single process.

Chemical species containing at least one externally reactive carbonyl group can be ketones, beta diketones, beta keto ester groups, their imine and enamine forms, and their aldehyde analogs. The imine and enamine forms can be in equilibrium with the carbonyl when the amine is present in the carbonyl-containing solution. Various chemical species are shown as follows.
-C (= O) R (wherein, R is an alkyl group or an aryl group of _C 1 _{-C 10} with respect to the ketone, R is H with respect to aldehyde)
-C (= ^NR 1) R (wherein, R is an alkyl group or an aryl group of _C 1 _{-C 10} with respect to the imine, R is H with respect to aldehyde analogs, ^{R 1} is alkyl of _C 1 _{-C 10} Group or aryl group)
^{-C = C (= NR 1 R} 2) R ( wherein, R is an alkyl group or an aryl group of _C 1 _{-C 10} with respect to enamine, R is H with respect to aldehyde analogs, ^{R 1} and ^{R 2} The same or different C _{1 to} C ₁₀ alkyl or aryl groups)
^{-X-C (= O) -C} (R 1) H-C (= O) -R ( wherein, X is CH ₂ with respect to beta-diketone, X with respect to the beta-keto ester is O or NH, ^{R 1} is an alkyl group or an aryl group of _C 1 _{-C 10,} R represents an alkyl group or an aryl group of _C 1 _{-C 10} with respect to the ketone, R is H with respect to aldehyde analogs)
—X—C (═O) —C (R ¹ ) HC— (NR ¹ ) —R (wherein X is CH ₂ , O or NH, and R ¹ is a C ₁ -C ₁₀ alkyl group. or an aryl group, R is an alkyl group or an aryl group of C ₁ -C ₁₀ with respect to the imine form analogs of diketones and esters of the above, R is H with respect to aldehyde analogs)
^{-X-C (= O) -C} (R 1) H = C (NR 1 R 2) -R ( wherein, X is _CH 2, O or NH, ^{R 1} and ^{R 2} are the same or different an alkyl group or an aryl group of C ₁ -C _10, R represents an alkyl group or an aryl group of C ₁ -C ₁₀ with respect enamine form analogs of diketones and esters of the above, R represents are H with respect to aldehyde analogs )

Chemical species containing at least one externally reactive carbonyl group also include a ketone group and an aldehyde group activated by an electron withdrawing group (EWD). The EWD can be a CN group, SO group, SO ₂ group, SO ₃ group, SO ₂ NH group, PO group, PO ₃ group or PO ₂ NH group. The point of attachment of these species to the pigment particle or entity that is covalently bound to the pigment particle species is either through the alpha carbon between the reactive carbonyl and the EWD, or through the EDW, if valence permits. It is possible that Various chemical species are shown as follows.

Where EWD is CN, SO, SO ₂ , SO ₃ , SO ₂ NH, PO, PO ₃ or PO ₂ NH group, R ¹ is a C ₁ -C ₁₀ alkyl group or aryl group, R is an alkyl group or an aryl group of C ₁ -C ₁₀ with respect to activated ketone, R is H for activity aldehyde.

The chemical species can also be a ketal, acetal, cyclic ketal or cyclic acetal group. Ketals and acetals are stable in neutrality or are slightly alkaline solutions, but return to reactive ketones or reactive aldehydes in the presence of acids. Various chemical species are shown as follows.
-C ^(-OR ₁₎ in 2 R (wherein, ^{R 1} is an alkyl group or an aryl group of _C 1 _{-C 10,} R is an alkyl group or an aryl group of _C 1 _{-C 10} with respect to a ketal, for acetal R is H)

(Wherein, R is an alkyl group or an aryl group of C ₁ -C ₁₀ with respect to the cyclic ketal, R is H with respect to the cyclic acetal)

  In all of the above species, R is preferably a methyl group or H.

  In summary, chemical species containing at least one externally reactive carbonyl group are ketones, aldehydes, beta diketones, beta keto ethers; imine and enamine forms of ketones, aldehydes, beta diketones and beta keto ethers, ketals, acetals , A cyclic ketal, a cyclic acetal, a ketone activated with an electron withdrawing group, an aldehyde activated with an electron withdrawing group, and combinations thereof. As used herein, a ketone or aldehyde group includes all of these groups.

  Referring now to the drawings, the carbon black pigment or organic pigment particles identified by reference number 10 and diazotization yield the desired carbonyl self-dispersing carbon black pigment or organic pigment particles identified by reference numbers 11-17. Seven examples of reactions with reagents are illustrated in FIG. The illustrated carbon black pigment particles or organic pigment particles 10 are surface functionalized to contain D groups to allow the formation of a stable dispersion in an aqueous vehicle. The dispersible D group can be introduced by any of the methods described above that are appropriate for a given pigment. The covalent bonding of the reactive ketone group or reactive aldehyde group to the pigment particle surface is performed by a diazotizing reagent.

  The diazotization precursor used in the reaction to produce the carbonyl self-dispersing pigment particles 11 was prepared as shown in FIG. 2 using paraaminoacetophenone, a commercially available compound that can be diazotized with sodium nitrite in aqueous HCl. Is done. Thereafter, the diazotized precursor is reacted with the dispersed pigment particles shown in FIG. 1 to provide the desired carbonyl self-dispersing pigment particles.

  The aminoketone used to prepare the diazotization precursor used in the reaction to produce the carbonyl self-dispersing pigment particles 12 or 14 is described by (Non-Patent Document 3) as shown in FIG. It is possible to manufacture using a synthetic strategy similar to the synthetic strategy. The chloro group on p-chloronitrobenzene is replaced with methyl acetoacetate anion, after which the nitro group is reduced, hydrolyzed and decarboxylated to give the amine, which is diazotized with sodium nitrite in aqueous HCl. It is possible. The diazotized precursor is then reacted with the dispersed pigment particles shown in FIG. 1 to provide the desired carbonyl self-dispersing pigment particles having a reactive aliphatic ketone group. An analog of this ketone, such as the analog used in the reaction to produce the desired carbonyl self-dispersing pigment particle 14 shown in FIG. 1, uses an alternative alkylating agent such as the alkylating agent shown in FIG. Can be prepared.

  The amine precursor used in the reaction to produce the carbonyl self-dispersing pigment particles 13 can be prepared by a synthetic route similar to the synthetic route described by (Non-Patent Document 4) shown in FIG. A commercially available sodium salt of sulfinic acid can be reacted with chloroacetone, after which the acetyl group is cleaved to form an amine and then diazotized. The amine precursor is then reacted with the dispersed pigment particles shown in FIG. 1 to provide the desired carbonyl self-dispersing pigment particles.

  The beta ketoamide precursor used in the reaction to produce the carbonyl self-dispersing pigment particles 15 and 16 is p-nitrobenzylamine in the case of 15 or p-nitroaniline in the case of 16, 2, 6 -It can be prepared by reacting with trimethyl-4H-1,3-dioxin-4-one. The nitro group is then reduced to the amine as shown and each is diazotized with sodium nitrite in aqueous HCl. The beta ketoamide precursor is then reacted with the dispersed pigment particles shown in FIG. 1 to provide the desired carbonyl self-dispersed pigment particles having reactive beta ketone groups.

  The diketone precursor used in the reaction to produce the carbonyl self-dispersing pigment particles 17 can be prepared as shown in FIG. 6 by starting with a blocked vinylsulfone sulfate ester that is reacted with an acetylacetone anion. . This is followed by cleavage of the acetyl group protecting the amine. The resulting amine can be diazotized with sodium nitrite in aqueous HCl. The diketone precursor is then reacted with the dispersed pigment particles to provide the desired carbonyl self-dispersing pigment particles having reactive beta diketone groups.

  Three examples of another route for producing self-dispersing carbon black or organic pigment particles having reactive carbonyl groups are illustrated in FIG. The carbon black pigment or organic pigment particles 20 are surface functionalized to contain D groups to allow the formation of a stable dispersion in an aqueous vehicle. Again, it is possible to introduce dispersible D groups by any of the methods described above that are appropriate for a given pigment. Reagents containing carbonyl groups and activated double bonds are reacted with pigment particles 20 to produce carbonyl self-dispersing pigment particles 21, 22, and 23. A ketone precursor to particles 22 can be prepared by reaction between diketene and phthalimide. Ketone reagent precursors for particles 22 and 23 are commercially available.

  Three examples of yet another route for producing self-dispersing carbon black or organic pigment particles having reactive carbonyl groups are illustrated in FIG. The carbon black or organic pigment particles 30 are surface functionalized to contain D groups. Reagents that can cleave into radicals and contain reactive carbonyl groups are reacted with pigment particles 30 to produce carbonyl self-dispersing pigment particles 31, 32, and 33. The preparation of azoketone precursors for 31, 32 and 33 is described in (Non-patent document 5) and (Non-patent document 6).

  It is possible to prepare carbonyl self-dispersing pigments by suitable reactions on stabilizing groups or other groups already attached to the pigment surface. (Non-Patent Document 7) describes a terminal amine or carbon atom functionalized with acyl azide, anhydride, acyl imidazole, p-nitrophenyl ester and pentachlorophenyl ester all derived from carboxyl groups added to the particle surface. It has been disclosed to attach polymers and oligomers through hydroxyl groups. Reagents containing both amines and reactive carbonyls or carbonyls as acetals or ketals can be added in the same manner to carboxylated carbon black and other organic pigments to form carbonyl self-dispersing pigments.

  (Non-Patent Document 8) discloses 4- (4,6-dimethoxy-1,3,5-triazine-2- 2) for preparing an amide of a carboxylic acid or a carboxylic ester in an aqueous solution with a yield of 70% or more. Yl) -4-methylmorpholinium chloride (DMTMM) is described. The reaction to form the activated ester can be performed in the presence of an amine. This chemistry is well suited for adding reagents containing ketones or aldehydes with amine groups directly to the D group of the carboxylated pigment directly in the aqueous phase as illustrated in FIG. Carboxylated dispersed pigment particles 40 are reacted with DMTMM to produce activated ester 41. As shown, aldehyde or ketone containing reagents are then reacted with the activated ester to produce carbonyl self-dispersing pigment particles 42 and 43.

  US Patent Publication (Patent Document 37) describes a self-dispersion that can be reacted with diazotized 2- (4-aminophenylsulfonyl) ethyl hydrogen sulfate and further reacted with an amine-containing reagent while in the aqueous phase. Carbon particles resulting in conductive carbon black pigment or organic pigment particles are disclosed. These pigment particles are reacted with polyamine species to prepare polymer-modified particles. For the purposes of the present invention, these pigment particles can be reacted with amines or other nucleophilic reagents containing carbonyls to produce carbonyl self-dispersing carbon black pigments or organic pigments. As illustrated in FIG. 10, the carbon black pigment particles or organic pigment particles 50 have a separate dispersion group so that the carbon black pigment or organic pigment particles 50 remain self-dispersing after all of the sulfate groups have been replaced. For example, it is possible to have a carboxyl and such a D group is shown in FIG. Reaction with diazotized 2- (4-aminophenylsulfonyl) ethyl hydrogen sulfate results in self-dispersing pigment particles 51. Precursor nucleophilic reagents are commercially available materials. Reaction of them with pigment particles 51 results in carbonyl self-dispersing carbon black pigment or organic pigment particles 52, 53 and 54.

Carbonyl self-dispersing inorganic pigments are another embodiment of the present invention. Oxide pigments such as TiO ₂ or iron oxide are preferred. The pigment may also retain one or more metal oxide surface coatings. These coatings may be applied using techniques known by those skilled in the art. Examples of metal oxide coatings include silica, alumina, alumina-silica and zirconia. The surfaces of these oxide particles contain hydroxyl groups that allow the surface to be functionalized with siloxane reagents containing reactive ketone groups. Examples of five reactions of different siloxane reagents and oxide pigment particles resulting in carbonyl self-dispersing oxide pigments are illustrated in FIG. Oxide particles 60 are reacted with the respective siloxanes to produce carbonyl self-dispersing oxide pigments 61-65. FIG. 12 illustrates a synthetic route to the five siloxane reagents used in the reaction shown in FIG.

Claims (18)

  One or more covalently stabilizing groups that enable the formation of a stable dispersion of the pigment in the liquid, and one or more covalently bonded species that contain at least one externally reactive carbonyl group, A self-dispersing pigment comprising pigment particles having The covalently bonded species containing at least one externally reactive carbonyl group is selected from the group consisting of C ₁ -C ₁₀ and combinations thereof, wherein
(C ₁ ) is —C (═O) R,
(C ₂ ) is —C (═NR ¹ ) R,
(C ₃ ) is —C (═NR ¹ R ² ) R,
(C ₄ ) is —X—C (═O) —C (R ¹ ) HC (═O) —R;
(C ₅ ) is —X—C (═O) —C (R ¹ ) H—C (═NR ¹ ) —R;
(C ₆ ) is —X—C (═O) —C (R ¹ ) H═C (═NR ¹ R ² ) —R;
(C ₇ ) is —C— (OR ¹ ) ₂ R,
_{(C 8)} is

And
_{(C 9)} is

And
_{(C 10)} is

And
Where
R _is an alkyl group or an aryl group or H of C 1 _{-C 10,}
R ¹ is a C _{1 to} C ₁₀ alkyl group or aryl group,
R ² is a C _{1 to} C ₁₀ alkyl group or aryl group,
X is CH ₂ , O or NH;
The pigment according to claim 1, wherein EWD is a CN, SO, SO ₂ , SO ₃ , SO ₂ NH, PO, PO _3, or PO ₂ NH group.   The pigment according to claim 2, wherein R is a methyl group or H.   The covalently bound stabilizing group allows the carboxylate, amine, sulfonate, sulfinate, phosphate, amine, quaternized amine or ethoxylate oligomer group to allow the pigment to form a stable dispersion in an aqueous liquid. The pigment according to claim 2, wherein the pigment is selected from the following.   The pigment according to claim 2, wherein the pigment particles are selected from the group consisting of organic colored pigment particles or inorganic pigment particles.   The pigment particles are carbon black containing a covalently bonded species that is oxidized to form carboxylate stabilizing groups on the surface and contains at least one externally reactive carbonyl group. The pigment according to claim 2.   A self-dispersing pigment comprising a liquid vehicle and a self-dispersing pigment, wherein the self-dispersing pigment comprises a covalently bonded stabilizing group and at least one external reactive carbonyl that enables the pigment to form a stable dispersion in the liquid vehicle. An ink-jet ink comprising pigment particles having covalently bound chemical species containing groups. The covalently bonded species containing at least one externally reactive carbonyl group is selected from the group consisting of any one of C _{1 to} C ₁₀ and combinations thereof, wherein
(C ₁ ) is —C (═O) R,
(C ₂ ) is —C (═NR ¹ ) R,
(C ₃ ) is —C═C (NR ¹ R ² ) R,
(C ₄ ) is —X—C (═O) —C (R ¹ ) HC (═O) —R;
(C ₅ ) is —X—C (═O) —C (R ¹ ) H—C (═NR ¹ ) —R;
(C ₆ ) is —X—C (═O) —C (R ¹ ) H═C (NR ¹ R ² ) —R;
(C ₇ ) is —C (—OR ¹ ) ₂ R,
_{(C 8)} is

And
_{(C 9)} is

And
_{(C 10)} is

And
Where
R _is an alkyl group or an aryl group or H of C 1 _{-C 10,}
R ¹ is a C _{1 to} C ₁₀ alkyl group or aryl group,
R ² is a C _{1 to} C ₁₀ alkyl group or aryl group,
X is CH ₂ , O or NH;
_EWD, the pigment of claim 7 _{CN, SO, SO 2, SO} 3, SO 2 NH, PO, characterized in that it is a PO ₃ or _PO 2 NH group.   9. The inkjet ink according to claim 8, wherein R is a methyl group or H.   The liquid vehicle is an aqueous vehicle and the covalently bonded stabilizing group allows the pigment to form a stable dispersion in the aqueous vehicle, carboxylate, amine, sulfonate, sulfinate, phosphate, amine, 9. Ink jet ink according to claim 8, characterized in that it is selected from quaternized amine or ethoxylate oligomer groups.   The ink-jet ink according to claim 8, wherein the pigment particles are selected from the group consisting of organic colored pigment particles or inorganic pigment particles.   The pigment particles are carbon black containing a carboxylate stabilizing group formed on an oxidized surface and containing a covalently bound chemical species containing at least one external reactive carbonyl group. The inkjet ink according to claim 8. An inkjet ink set comprising at least a first ink and a second ink,
(A) the first ink comprises a liquid vehicle and a self-dispersing pigment, the self-dispersing pigment being a covalently bonded stabilizing group that enables the pigment to form a stable dispersion in the liquid vehicle; And pigment particles having at least one covalently bound chemical species containing at least one externally reactive carbonyl group,
(B) The inkjet ink set, wherein the second ink includes a liquid vehicle and a chemical species having at least one reactive amine group. The covalently bonded species containing at least one externally reactive carbonyl group is selected from the group consisting of any one of C ₁ -C ₈ and combinations thereof, wherein
(C ₁ ) is —C (═O) R,
(C ₂ ) is —C (═NR ¹ ) R,
(C ₃ ) is —C═C (NR ¹ R ² ) R,
(C ₄ ) is —X—C (═O) —C (R ¹ ) HC (═O) —R;
(C ₅ ) is —X—C (═O) —C (R ¹ ) H—C (═NR ¹ ) —R;
(C ₆ ) is —X—C (═O) —C (R ¹ ) H═C (NR ¹ R ² ) —R;
(C ₇ ) is —C (—OR ¹ ) ₂ R,
_{(C 8)} is

And
_{(C 9)} is

And
_{(C 10)} is

And
Where
R _is an alkyl group or an aryl group or H of C 1 _{-C 10,}
R ¹ is a C _{1 to} C ₁₀ alkyl group or aryl group,
R ² is a C _{1 to} C ₁₀ alkyl group or aryl group,
X is CH ₂ , O or NH;
EWD _{is, CN, SO, SO 2,} SO 3, SO 2 NH, PO, inkjet ink set according to claim 13, which is a PO ₃ or _PO 2 NH group.   The inkjet ink set according to claim 14, wherein R is a methyl group or H.   The liquid vehicle of the first ink is an aqueous vehicle, and the covalent stabilizing group allows the carboxylate, amine, sulfonate, sulfinate, phosphate to allow the pigment to form a stable dispersion in the aqueous vehicle. The inkjet ink set of claim 14, wherein the ink set is selected from amine, quaternized amine or ethoxylate oligomer groups.   The inkjet ink set according to claim 14, wherein the pigment particles are selected from the group consisting of organic colored pigment particles or inorganic pigment particles.   The pigment particles are carbon black containing a covalent species that is oxidized to form carboxylate stabilizing groups on the surface and contains at least one externally reactive carbonyl group. Item 15. The inkjet ink set according to Item 14.

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