WO2005054381A1

WO2005054381A1 - Solvent based colorant preparations for ink jet printing

Info

Publication number: WO2005054381A1
Application number: PCT/EP2004/013434
Authority: WO
Inventors: Mike Husbands; Sarup Panesar; Heidemarie Menzel; Klaus Saitmacher
Original assignee: Clariant GmbH
Current assignee: Clariant Produkte Deutschland GmbH
Priority date: 2003-12-06
Filing date: 2004-11-26
Publication date: 2005-06-16
Anticipated expiration: 2006-06-06
Also published as: GB0328340D0

Abstract

The invention relates to solvent-based colorant preparations, comprising (A) an organic and/or inorganic colorant, (B) an organic solvent, (C) an aldehyde resin, (D) an alkylammonium salt of an acidic polymer, (E) optionally a vinyichloride-vinylacetate copolymer, (F) optionally a polymeric dispersant having a molecular weight of 500 to 500.000 g/mol, (G) optionally other standard additives.

Description

Solvent based colorant preparations for ink jet printing

The present invention relates to solvent based colorant preparations.

The ink jet printing process, like for example electrophotography (laser printers and copiers), is a nonimpact printing process and has become more and more important, especially in the small office, home office (SOHO) sector, especially in the wide-size-range, owing to the increasing use of computers.

Ink jet printing technology distinguishes between the so-called continuous printing processes and the drop-on-demand processes, the drops in question being ink drops which are generated by a computer-controlled electrical signal. There are basically two kinds of drop-on-demand ink jet processes, namely thermal ink jet, also known as bubble jet, and piezoelectric ink jet.

Thermal and piezoelectric ink jet have hitherto employed inks which are based on solutions of water-soluble dyes, which is why the prints possess high brilliance and optical density, but insufficient lightfastness and poor water resistance. These disadvantages of dye-based ink jet inks can only be partly overcome by the use of specialty papers. One way of overcoming the aforementioned disadvantages of dye-based inks would be to use pigmented inks. Pigmented inks for ink jet printing would have to meet a whole series of requirements. They have to have a viscosity and surface tension suitable for printing, they have to be stable in storage, ie they should not coagulate and the dispersed pigment should not sediment, they must not clog the printer nozzles, which can be problematical in the case of pigment particle inks especially. Similarly, the purity of the preparations has to meet high requirements, since excessive concentrations of inorganic or organic salts and ions, especially chloride ions, lead to corrosion and hence to premature destruction of the print heads or in the case of bubble jet printers to harmful deposits on the heating elements. High standards are required especially of the color strength, the hue, the brilliance, transparency and fastness properties, for example lightfastness, waterfastness and rubfastness of the pigments and prints. High lightfastness is important especially when the ink jet process is to be used to produce prints of photographic quality or for outdoor use.

A fine state of subdivision is a basic prerequisite for pigment preparations for use in ink jet printing, since the avoidance of nozzle clogging requires that the average pigment particle size not exceed 200 nm, ideally 150 nm, and that the particle size distribution be very narrow, so that even the maximum particle size does not exceed 500 nm. As well as a fine state of subdivision, it is particularly the flocculation resistance which is a very important quality criterion of an ink jet preparation, which is why crystal growth or agglomeration of the pigment particles has to be effectively prevented by means of suitable additives. This is usually accomplished by means of certain dispersing assistants. A pigment dispersion property closely related to its flocculation resistance is its stability in storage, since the pigment particles must not agglomerate during prolonged storage, even at elevated or reduced temperatures compared with room temperature. During printing, pigmented inks are subjected to extreme thermal and mechanical stresses; the dispersing assistant has to ensure pigment dispersion stability even in these circumstances. Transient temperature jumps of up to 500°C occur in thermal ink jet. Even in these conditions, the pigment may neither flocculate or sediment on the heating elements of the printer nor clog the printer nozzles. In printing, the pigmented ink is flung through a narrow nozzle; extremely high shearing stresses occur in the process, but they must not cause the dispersing assistant to be sheared off the pigment surface.

Accordingly, the dispersing assistant used is of decisive importance, not only because it determines the physical properties, for example surface tension and viscosity, of the dispersions, but also because it shall stabilize the inks against flocculation in the course of storage and deterioration in the course of the printing operation. In addition, the dispersant has much influence on the droplet formation during the printing process. A uniform droplet formation free of satellites is prerequisite for high performance ink-jet prints , e.g. in photoprinting. WO 00/20519 discloses pigment dispersions of inorganic pigments for ink-jet printing containing several dispersants for inorganic pigments.

EP-A-0448055 describes aqueous ink-jet recording fluids consisting of pigments and dispersants containing at least one sulfo group. " 5

Prior art pigmented preparations for ink jet printing often fail to meet printer manufacturers' requirements in that they are deficient in fineness of grind, thermal stability and stability in storage.

In particular, the stability problems of pigmented ink jet inks are closely related to 10 adequate stabilization of the pigment particles in the solvent based suspensions.

It is therefore an objective of the present invention to provide colorant preparations which meet the above mentioned requirements for the ink jet printing process.

15 The present invention accordingly provides colorant preparations comprising

A) an inorganic and/or organic colorant,

B) an organic solvent,

C) an aldehyde resin,

D) an alkylammonium salt of an acidic polymeric compound, 20 E) optionally a vinylchloride-vinylacetate copolymer,

F) optionally a polymeric dispersant having a molecular mass of from 500 to 500,000 g/mol,

G) optionally further standard additives for ink-jet preparations.

25 The present invention accordingly provides colorant preparations consisting essentially of

A) 0.1 to 50% by weight and preferably 1 to 30% by weight of at least one colorant selected from the group consisting of organic pigments and inorganic pigments, 30 B) 5 to 80% by weight and preferably 10 to 50% by weight of at least one organic solvent, C) 0.1 to 50% by weight and preferably 0.2 to 30% by weight of at least one aldehyde resin, D) 0.1 to 30% by weight and preferably 1 to 20% by weight of at least one alkylammonium salt of an acidic polymeric compound,

E) 0 to 30% by weight and preferably 0.1 to 10% by weight of vinylchloride- vinylacetate copolymer, F) 0 to 10% by weight and preferably 0.1 to 5% by weight of a polymeric dispersant having a molecular mass of from 1000 to 500,000 g/mol, G) 0 to 10% by weight and preferably 0.1 to 5% by weight of further standard additives for ink-jet preparations, each percentage being based on the total weight of the colorant preparation (100% by weight).

Component (A) is a finely divided organic or inorganic pigment and/or organic dye or a mixture of various organic and/or inorganic pigments and/or organic dyes. The pigments are preferably used in the form of dry powders.

Useful organic pigments include a monoazo, disazo, laked azo, β-naphthol, Naphtol AS, benzimidazolone, disazo condensation, azo metal complex pigment or a polycyclic pigment, such as for example a phthalocyanine, quinacridone, perylene, perinone, thiazineindigo, thioindigo, anthanthrone, anthraquinone, flavanthrone, indanthrone, isoviolanthrone, pyranthrone, dioxazine, quinophthalone, isoindolinone, isoindoline or diketopyrrolopyrrole pigment or carbon black.

Useful organic pigments also include modified pigments which surface has been modified by chemical processes such as sulfonation or diazotization or grafted with charged groups or polymer chains.

Useful inorganic pigments include for example titanium dioxides, zinc sulfides, iron oxides, chromium oxides, ultramarine, nickel- or chromium antimony titanium oxides, cobalt oxides and bismuth vanadates.

Useful organic dyes include acid dyes, dispersion dyes, direct dyes, sulfur dyes, metalcomplex dyes or reactive dyes; in the case of reactive dyes, dyes which have been reacted with nucleophiles can be used as well. The pigments used should have a light fastness higher than 5, preferably higher than 6 (determined by means of a blue scale). The pigments used should be very finely divided, in that 95% (preferably 99%) of the pigment particles should have a particle size < 500 nm. The average particle size is preferably < 150 nm. Depending on the pigment used, the morphology of the pigment particles can vary widely, and accordingly the viscosity behavior of the pigment preparations can vary widely as a function of the particle shape. To obtain a favorable viscosity behavior for the preparations, the particles should preferably have a cuboid or spherical shape. Preferred are pure or, where necessary, purified pigments with very low organic or inorganic impurities.

A selection of particularly preferred organic pigments are carbon black pigments, for example lampblacks or furnace blacks; monoazo and disazo pigments, especially the Colour Index pigments Pigment Yellow 1 , Pigment Yellow 3, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 16, Pigment Yellow 17, Pigment Yellow 73, Pigment Yellow 74, Pigment Yellow 81 , Pigment Yellow 83, Pigment Yellow 87, Pigment Yellow 97, Pigment Yellow 111, Pigment Yellow 126, Pigment Yellow 127, Pigment Yellow 128, Pigment Yellow 155, Pigment Yellow 174, Pigment Yellow 176, Pigment Yellow 191, Pigment Yellow 213, Pigment Yellow 214, Pigment Red 38, Pigment Red 144, Pigment Red 214, Pigment Red 242, Pigment Red 262, Pigment Red 266, Pigment Red 269, Pigment Red 274, Pigment Orange 13, Pigment Orange 34 or Pigment Brown 41 ; β-naphthol- und Naphthol AS-pigments, especially the Colour Index Pigments Pigment Red 2, Pigment Red 3, Pigment Red 4, Pigment Red 5, Pigment Red 9, Pigment Red 12, Pigment Red 14, Pigment Red 53:1 , Pigment Red 112, Pigment Red 146, Pigment Red 147, Pigment Red 170, Pigment Red 184, Pigment Red 187, Pigment Red 188, Pigment Red 210, Pigment Red 247, Pigment Red 253, Pigment Red 256, Pigment Orange 5, Pigment Orange 38 or Pigment Brown 1; laked azo- and metal complex pigments, especially the Colour Index Pigments Pigment Red 48:2, Pigment Red 48:3, Pigment Red 48:4, Pigment Red 57:1, Pigment Red 257, Pigment Orange 68 or Pigment Orange 70; benzimidazoline pigments, especially the Colour Index Pigments Pigment Yellow 120, Pigment Yellow 151, Pigment Yellow 154, Pigment Yellow 175, Pigment Yellow 180, Pigment Yellow 181, Pigment Yellow 194, Pigment Red 175, Pigment Red 176, Pigment Red 185, Pigment Red 208, Pigment Violet 32, Pigment Orange 36, Pigment Orange 62, Pigment Orange 72 or Pigment Brown 25; isoindolinone and isoindoline pigments, especially the Colour Index Pigments Pigment Yellow 139 or Pigment Yellow 173; phthalocyanine pigments, especially the Colour Index Pigments Pigment Blue 15, Pigment Blue 15:1, Pigment Blue 15:2, Pigment Blue 15:3, Pigment Blue 15:4, Pigment Blue 15:6, Pigment Blue 16, Pigment Green 7 or Pigment Green 36; anthanthrone, anthraquinone, quinacridone, dioxazine, indanthrone, perylene, perinone and thioindigo pigments, especially the Colour index Pigments Pigment Yellow 196, Pigment Red 122, Pigment Red 149, Pigment Red 168, Pigment Red 177, Pigment Red 179, Pigment Red 181, Pigment Red 207, Pigment Red 209, Pigment Red 263, Pigment Blue 60, Pigment Violet 19, Pigment Violet 23 or Pigment Orange 43; triarylcarbonium pigments, especially the Colour Index Pigments Pigment Red 169, Pigment Blue 56 or Pigment Blue 61 ; diketopyrrolopyrrole pigments, especially the Colour Index Pigments Pigment Red 254.

Examples of especially preferred organic dyes are the Colour Index dyes Acid Yellow 17, Acid Yellow 23, Direct Yellow 86, Direct Yellow 98, Direct Yellow 132, Reactive Yellow 37, Acid Red 52, Acid Red 289, Reactive Red 23, Reactive Red 180, Acid Blue 9, Direct Blue 199 and reactive dyes reacted with nucleophiles.

Component (B) is preferably a compound of the formula

wherein

Rι, R² and R³ independently of each other are a substituted or unsubstituted, branched or straight-chain CrC₂o-alkyl- or C₃-C₂o-cycloalkyl or a substituted or unsubstituted, branched or straight-chain C₂-C₂o-alkenyl- or C₃-C₂o-cycloalkenyl, wherein the substituents are preferably 1 , 2, 3 or 4 substituents selected from the group consisting of halogen, aryl, aryl(CrC₂o)alkyl, C₅-C₆-cycloalkyl, hetaryl, hetaryl(CrC₂₀)alkyl or Cι-C₂o-alkoxy, and n is a number of from 1 to 100, especially 1 to 20. Preferred radicals R-i, R₂ and R₃ are Cι₂-Cι₈-alkyl (branched or straight-chain) or C-i2-Ci₈-alkenyl (branched or straight-chain), which are substituted by 1 , 2, 3 or 4 substituents selected from the group consisting of halogen, aryl, aryl(Cι-C4)alkyl, hetaryl, hetaryl(Cι-C₄)alkyl or CrC4-alkoxy. „Aryl" means herein an aromatic radical, having preferably 6 to 15 carbon atoms. Examples are phenyl, naphthyl, anthryl and phenanthryl. „Hetaryl" means herein an aromatic radical, having preferably 1 to 10 carbon atoms and 1 , 2, 3 or 4 heteroatoms selected from the group consisting of O, N, S or P. Examples are pyrrolyl, furyl, thiophenyl, indolyl, isoindolyl, indolizinyl, benzofuryl, benzothiophenyl, pyrazolyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, triazolyl, tetrazolyl, pyridyl, quinolinyl, isoquinolinyl, pyridazinyl, pyrimidinyl, pyrazinyl and triazinyl.

Examples for organic solvents (component B) are: CH3-0-CH₂-CH(CH₃)-0-CO-CH3

CH3-CH2-O-CH2-CH2-O-CH2-CH2-O-CO-CH3

CH₃-CH₂-CH₂-CH₂-0-CH₂-CH₂-0-CO-CH₃

CH₃-CH(CH₃)-CH2-CH2-0-CO-CH3

CH3-CH2-O-CH2-CH2-O-CO-CH3 cyclohexanone.

Component C is preferably an urea/formaldehyde resin, wherein the aldehyde is preferably a Cι-C₄-aldehyde, especially formaldehyde, or an aliphatic dialdehyde, such as glyoxal. Urea/formaldehyde resins are commercially available under the trade name ©Laropal (BASF). These products are low-molecular condensation products of urea and aliphatic aldehydes, having a softening point between 70 and 110°C.

Component D are preferably alkylammonium salts of phosphonopolyalkoxylates having an average molecular weight Mw of between 500 and 10000 g/mol and an acid number of between 50 and 200 mg KOH/g. Such products are commercially available, for example under the trade name ©Disperbyk (Byk-Chemie GmbH). Component E are granular or powder copolymers of vinylchloride and vinylacetate, preferably having a vinylchloride content of between 70 and 90 % by weight and a glass transition temperature (DIN 53 765) of between 60 and 100°C. Such products are commercially available under the trade name ©Vinnol (Wacker Polymer Systems GmbH).

Component (F) are polymeric dispersants having a molecular mass of from 500 to 500,000 g/mol, especially 1000 to 500,000 g/mol. These dispersants can be nonionic, anionic or cationic or amphoteric compounds, such as:

Polyethyleneoxides, polypropyleneoxides, polyoxymethylenes, polytrimethyleneoxides, polyvinylmethylethers, polyethyleneimines, polyacrylic acids, polyarylamides, polymethacrylic acids, polymethacrylamides, poly-N.N- dimethylacrylamides, poly-N-isopropylacrylamides, poly-N-acrylglycinamides, poly- N-methacrylglycinamides, polyvinylalcoholes, polyvinylacetates, copolymers of polyvinylalcoholes and polyvinylacetates, polyvinylpyrrolidone, polyvinyloxazolidone, polyvinylmethyloxazolidone, further nonionic dispersants such as reaction products of alkyleneoxides with fatty alcohols, fatty amines, fatty acids, phenols, alkylphenols, arylalkylphenols, such as styrene-phenol- condensates, carbonic amides and resin acids.

The colorant preparations according to the invention may further include, as component (G), further, especially customary ink jet ink additives, for example preservatives, antioxidants, cationic, anionic, amphoteric or nonionic surface- active substances (surfactants and wetting agents), degassers/defoamers and also agents for regulating the viscosity, for example natural or artificial resins and polymers as film-formers or binders to enhance the adhesion and abrasion resistance.

This invention further provides a process for producing the colorant preparations according to the invention, which comprises homogenizing colorant (A), preferably as powder, together with components (B), (C), (D), and optionally (E), (F) and (G) and finely dividing with the aid of a milling or dispersing device. Preferably, in a first step at least one colorant (component A), preferably as a powder, is pasted up together with the other components and then homogenized with a dissolver or some other suitable device and predispersed. Then a fine dispersion operation follows using a bead mill or some other suitable dispersing device to the desired particle size distribution with cooling. After the fine dispersion operation, the colorant preparation is diluted with organic solvent (and other ingredients as necessary) to the desired colorant concentration.

The colorant compositions according to the invention can be employed for the pigmenting of high-molecular-weight organic materials of natural or synthetic origin, for example of plastics, resins, surface coatings, paints, electrophotographic toners and developers, electret materials, colour filters and of writing and printing inks and seed.

High-molecular-weight organic materials which can be coloured with the colorant preparations according to the invention are, for example, cellulose compounds, such as, for example, cellulose ethers and esters, such as ethylcellulose, nitrocellulose, cellulose acetates or cellulose butyrates, natural binders, such as, for example, fatty acids, fatty oils, resins and conversion products thereof, or synthetic resins, such as polycondensates, polyadducts, polyaddition and copolyaddition products, such as, for example, amino plastics, in particular urea- and melamine-formaldehyde resins, alkyd resins, acrylic resins, phenolics and phenol resins, such as novolaks or resols, urea resins, polyvinyls, such as polyvinyl alcohols, polyvinyl acetals, polyvinyl acetates or polyvinyl ethers, polycarbonates, polyolefins, such as polystyrene, polyvinyl chloride, polyethylene or polypropylene, poly(meth)acrylates and copolymers thereof, such as polyacrylates or polyacrylonitriles, polyamides, polyesters, polyurethanes, coumarone-indene and hydrocarbon resins, epoxy resins, unsaturated synthetic resins (polyesters and acrylates) with various curing mechanisms, waxes, aldehyde and ketone resins, unvulcanized and vulcanized rubber and derivatives thereof and latices, casein, silicones and silicone resins; individually or in mixtures. It is unimportant here whether the high-molecular-weight organic compounds mentioned are in the form of plastic compositions, melts or in the form of spinning solutions, dispersions, surface coatings, paints or printing inks. Depending on the application, it proves advantageous to use the colorant preparations according to the invention as a blend or in the form of preparations or dispersions. Based on the high-molecular-weight organic material to be pigmented, the colorant preparations according to the invention are employed in an amount of from 0.05 to 30% by weight, preferably from 0.1 to 15% by weight.

The colorant preparations according to the invention are also suitable as colorants in electrophotographic toners and developers, such as, for example, one- or two- component powder toners (also known as one- or two-component developers), magnetic toners, liquid toners, latex toners, polymerization toners and special toners.

Typical toner binders are polymerization, polyaddition and polycondensation resins, such as styrene, styrene-acrylate, styrene-butadiene, acrylate, polyester and phenol-epoxy resins, polysulphones, polyurethanes, individually or in combination, and polyethylene and polypropylene, which may also contain further ingredients, such as charge-control agents, waxes, or flow-control agents, or are subsequently modified by means of these additives.

The colorant preparations according to the invention are furthermore suitable as colorants in powders and powder coatings, in particular in triboelectrically or electrokinetically sprayable powder coatings, which are used for the surface coating of articles made from, for example, metal, wood, plastic, glass, ceramic, concrete, textile material, paper or rubber. Powder coating resins which are typically employed are epoxy resins, carboxyl- and hydroxyl-containing polyester resins, polyurethane and acrylic resins, together with conventional curing agents. Combinations of resins are also used. Thus, for example, epoxy resins are frequently employed in combination with carboxyl- and hydroxyl-containing polyester resins. Typical curing-agent components (depending on the resin system) are, for example, acid anhydrides, imidazoles and dicyandiamide and derivatives thereof, blocked isocyanates, bisacylurethanes, phenol and melamine resins, triglycidyl isocyanurates, oxazolines and dicarboxylic acids. The invention furthermore relates to the use of the colorant preparation described as colorant for printing inks, in particular for ink-jet inks. The term ink-jet inks is taken to mean both water-based (including microemulsion inks) and solvent-based inks, UV-curable inks and inks which work by the hot-melt process.

Solvent-based ink-jet inks essentially comprise from 0.5 to 30% by weight, preferably from 1 to 15% by weight, of one or more of the colorant preparations according to the invention, from 70 to 95% by weight of an organic solvent or solvent mixture and/or a hydrotropic compound. If desired, the solvent-based ink- jet inks may comprise carrier materials and binders which are soluble in the

"solvent", such as, for example, polyolefins, natural and synthetic rubber, polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, polyvinylbutyrals, wax/latex systems or combinations of these compounds. If desired, the solvent-based ink-jet inks may also comprise binders and further additives, such as, for example, wetting agents, degassing agents/antifoams, preservatives and antioxidants.

Microemulsion inks are based on organic solvents, water and, if desired, an additional substance which acts as surface-active agent (surfactant). Microemulsion inks comprise from 0.5 to 30% by weight, preferably from 1 to 15% by weight, of one or more of the colorant preparations according to the invention, from 0.5 to 95% by weight of water and from 0.5 to 95% by weight of organic solvents and/or surfactants.

UV-curable inks essentially comprise from 0.5 to 30% by weight of one or more of the colorant preparations according to the invention, from 0.5 to 95% by weight of water, from 0.5 to 95% by weight of an organic solvent or solvent mixture, from 0.5 to 50% by weight of a radiation-curable binder and, if desired, from 0 to 10% by weight of a photoinitiator.

Hot-melt inks are usually based on waxes, fatty acids, fatty alcohols or sulphonamides which are solid at room temperature and become liquid on warming, where the preferred melting range is between about 60 and about

140°C. Hot-melt ink-jet inks essentially consist of from 20 to 90% by weight of wax and from 1 to 10% by weight of one or more of the colorant preparations according to the invention. It is furthermore possible for from 0 to 20% by weight of an additional polymer (as "colorant dissolver"), from 0 to 5% by weight of dispersants, from 0 to 20% by weight of viscosity modifiers, from 0 to 20% by weight of plasticizers, from 0 to 10% by weight of tackifying agent, from 0 to 10% by weight of transparency stabilizer (prevents, for example, crystallization of the wax) and from 0 to 2% by weight of antioxidant to be present.

The printing inks, in particular ink-jet inks, according to the invention can be prepared by dispersing the colorant preparations into the microemulsion medium, into the non-aqueous medium or into the medium for the preparation of the UV- curable ink or into the wax for the preparation of a hot-melt ink-jet ink. For ink-jet applications, the resultant printing inks are advantageously subsequently filtered (for example through a 1 μm filter).

The colorant preparations according to the invention are furthermore also suitable as colorants for colour filters, for both additive and subtractive production of colour, and as colorants for electronic inks (e-inks) or electronic paper (e-paper). In the production of so-called colour filters, both reflective and transparent colour filters, pigments in the form of a paste or in the form of pigmented photoresists in suitable binders (acrylates, acrylic esters, polyimides, polyvinyl alcohols, epoxides, polyesters, melamines, gelatines and caseins) are applied to the respective LCD components (for example TFT-LCD = thin film transistor liquid crystal displays or, for example, (S)TN-LCD = (super)twisted nematic LCD). In addition to high thermal stability, a further prerequisite for a stable paste or a pigmented photoresist is high pigment purity. In addition, the pigmented colour filters may also be applied by ink-jet printing processes or other suitable printing processes.

The colorant preparations of the present invention can further be used in an ink set in combination with black, yellow, magenta, cyan, optionally green and optionally orange colorants. Preference is here given to a set of printing inks whose black formulation contains a carbon black, especially a gas or furnace black, as a colorant, whose cyan formulation contains a pigment of the group of the phthalocyanine, indanthrone or triarylcarbonium pigments, especially the Colour Index pigments Pigment Blue 15, Pigment Blue 15:1, Pigment Blue 15:2, Pigment Blue 15:3, Pigment Blue 15:4, Pigment Blue 16, Pigment Blue 56, Pigment Blue 60 or Pigment Blue 61; whose magenta formulation contains a pigment of the group of the monoazo, disazo, β-naphthol, Naphthol AS, laked azo, metal complex, benzimidazolone, anthanthrone, anthraquinone, quinacridone, dioxazine, perylene, thioindigo, triarylcarbonium or diketopyrrolopyrrole pigments, especially the Colour Index pigments Pigment Red 2, Pigment Red 3, Pigment Red 4, Pigment Red 5, Pigment Red 9, Pigment Red 12, Pigment Red 14, Pigment Red 38, Pigment Red 48:2, Pigment Red 48:3, Pigment Red 48:4, Pigment Red 53:1, Pigment Red 57:1, Pigment Red 112, Pigment Red 122, Pigment Red 144, Pigment Red 146, Pigment Red 147, Pigment Red 149, Pigment Red 168, Pigment Red 169, Pigment Red 170, Pigment Red 175, Pigment Red 176, Pigment Red 177, Pigment Red 179, Pigment Red 181, Pigment Red 184, Pigment Red 185, Pigment Red 187, Pigment Red 188, Pigment Red 207, Pigment Red 208, Pigment Red 209, Pigment Red 210, Pigment Red 214, Pigment Red 242, Pigment Red 247, Pigment Red 253, Pigment Red 254, Pigment Red 256, Pigment Red 257, Pigment Red 262, Pigment Red 263, Pigment Red 266, Pigment Red 269, Pigment Red 274, Pigment Violet 19, Pigment Violet 23 or Pigment Violet 32; whose yellow formulation preferably contains a pigment of the group of the monoazo, disazo, benzimidazoline, isoindolinone, isoindoline or perinone pigments, especially the Colour Index pigments Pigment Yellow 1 , Pigment Yellow 3, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 16, Pigment Yellow 17, Pigment Yellow 73, Pigment Yellow 74, Pigment Yellow 81 , Pigment Yellow 83, Pigment Yellow 87, Pigment Yellow 97, Pigment Yellow 111, Pigment Yellow 120, Pigment Yellow 126, Pigment Yellow 127, Pigment Yellow 128, Pigment Yellow 139, Pigment Yellow 151, Pigment Yellow 154, Pigment Yellow 155, Pigment Yellow 173, Pigment Yellow 174, Pigment Yellow 175, Pigment Yellow 176, Pigment Yellow 180, Pigment Yellow 181, Pigment Yellow 191, Pigment Yellow 194, Pigment Yellow 196, Pigment Yellow 213, Pigment Yellow 214; whose orange formulation preferably contains a pigment of the group of the disazo, β-naphthol, Naphthol AS, benzimidazolone or perinone pigments, especially the Colour Index pigments Pigment Orange 5, Pigment Orange 13, Pigment Orange 34, Pigment Orange 36, Pigment Orange 38, Pigment Orange 43, Pigment Orange 62, Pigment Orange 68, Pigment

Orange 70, Pigment Orange 72 or Pigment Orange 74; whose green formulation preferably contains a pigment of the group of the phthalocyanine pigments, especially the Colour Index pigments Pigment Green 7 or Pigment Green 36.

The colorant preparations according to the invention facilitate low viscosities, which is of major importance, in particular, for applications in the ink-jet area, and rapid migration of the dispersant to the ink-droplet surface newly forming during the printing operation and thus stable and uniform droplet formation. In this way, ink-jet prints of high quality are possible. A further problem which is frequently associated with the use of polymers in ink-jet inks is their tendency to solidify in the nozzles of the printing head, which results in nozzle clogging and thus in poor printing behaviour. This type of failure of the nozzles is not observed on use of the colorant preparation according to the invention, which facilitates streak-free and thus uniform printing. The printing inks according to the invention are suitable for use in all conventional ink-jet printers, in particular for those based on the bubble-jet or piezo method.

In addition to the printing of paper, natural or synthetic fibre materials, films or plastics, the colorant preparations according to the invention can be used for the printing of a very wide variety of types of coated or uncoated substrate materials, thus, for example, for the printing of card, cardboard, wood and wood materials, metallic materials, semiconductor materials, ceramic materials, glasses, glass and ceramic fibres, inorganic materials, concrete, leather, foods, cosmetics, skin and hair. The substrate material here can have a two-dimensionally planar or spatially extended, i.e. three-dimensional shape and can be either completely or only partly printed or coated. It has been found that the colorant preparations according to the invention have overall advantageous application properties and satisfy the objects and requirements mentioned above extremely well, in particular in ink-jet printing. The viscosity of the ink-jet inks prepared therefrom is usually low (< 15 mPa s at 400 s^" ¹ in the case of the pigment preparations) and remains stable both at room temperature and during storage at 60°C for 4 weeks. The pigment particles in the dispersion have an average particle size of < 150 nm (determined after photosedimentation in a disc centrifuge), and the particle-size distribution remains virtually unchanged or only changes to an insignificant extent during storage. The inks prepared from the preparations are distinguished, in particular, by extremely good behaviour in ink-jet printing and by good stability during storage and in the ink-jet printing process. Furthermore, the prints produced are distinguished by high light fastness.

Examples

I. Preparation of a pigment preparation

For the preparation of the pigment preparation, the corresponding pigment is formed into a paste together with the other components and then homogenized using a dissolver (©Pendraulik, model LD 50) or another suitable apparatus and pre-dispersed. The subsequent microdispersion was carried out with the aid of a bead mill (VMA-Getzmann Dispermat model AE-6-C or a MiniZETA 03 from Netzsch), with the grinding being carried out with cooling to the desired particle- size distribution of the pigment particles. The dispersion was subsequently adjusted to the desired final pigment concentration using solvent component (B). The pigment preparations described in the following examples were prepared by the process described above, with the following constituents being used in the stated amounts so as to give 100 parts of the respective pigment preparation: Example 1

25 Parts C.I. Pigment Yellow 155 (Component A)

30 Parts Aldehyde resin ©Laropal A 81 (Component C) 10 Parts Alkylammonium salt of an acidic polymer (®Disperbyk-140) (Component D)

Rest Ethoxyethylacetate (Component B)

Example 2

20 Parts C.I. Pigment Red 122 (Component A) 30 Parts Aldehyde resin ©Laropal A 81 (Component C) 10 Parts Alkylammonium salt of an acidic polymer (®Disperbyk-140) (Component D) Rest Ethoxyethylacetate (Component B)

Example 3

20 Parts C.I. Pigment Blue 15:3 (Component A) 30 Parts Aldehyde resin ©Laropal A 81 (Component C)

10 Parts Alkylammonium salt of an acidic polymer (®Disperbyk-140)

(Component D) 0,5 Parts Dispersant ©Solperse 5000 (Sulfonated phthalocyanine), (Component G) Rest Ethoxyethylacetate (Component B)

Example 4

20 Parts C.I. Pigment Violet 19 (Component A) 30 Parts Aldehyde resin ©Laropal A 81 (Component C)

10 Parts Alkylammonium salt of an acidic polymer (®Disperbyk-140)

(Component D) Rest Ethoxyethylacetate (Component B) Example 5

25 Parts C. I. Pigment Black 7 (Component A)

Rest Ethoxyethylacetate (Component B).

Investigation of the physical properties of the colorant preparations:

The dispersed pigment particles should be very finely dispersed, i.e. the mean particle size D₅₀ should not exceed a value of 150 nm. The mean particle sizes D₅o of the preparations were determined after photo- sedimentation in a disc centrifuge (Table 1 ).

Table 1

Testing of the ink-jet inks prepared from colorant preparations:

In order to test the quality of ink-jet inks prepared from colorant preparations, the pigment preparations were first microfiltered through a 1 μm filter in order to remove abrasion dust from the grinding media and any coarse fractions. The filtered preparations were then diluted with suitable solvents. The test inks for yellow, magenta and cyan had the following composition:

16 parts of pigment preparation (cf. Examples 1 to 5) 42 parts of cyclohexanone 42 parts of n-butyl lactate

This corresponds to a pigment content of from 3 to 4% by weight in the respective ink. The composition of the test inks here was selected in such a way that the viscosity was in the range from 1.5 to 5 mPas.

The test inks were characterized using the following methods and instruments:

Filterability test:

200 ml of the ink-jet inks were filtered through a Sartorius glass-fibre filter (glass microfibre GMF 4, Ser. No. FT-3-1104-047) at room temperature and under reduced pressure. The time in seconds required for all the ink is measured. If the filter were to become blocked during the filtration, the quality criterion would not be achieved.

Viscosity of the inks:

The viscosity was determined using a Haake RS1 plate-and-cone viscometer at a temperature of 20°C, with the dependence of the viscosity on the shear rate being investigated in the range from 0 to 700 s^"1. The viscosity values shown in Table 2 were measured at a shear rate of 400 s^"1. For assessment of the storage stability of the dispersions, the viscosity was measured directly after preparation and after storage at 60°C for four weeks. The viscosities of the fresh samples are without exception between 3 and 9 mPas and are thus below 15 mPas. The measurement results show that storage at 60°C causes only very slight changes in viscosity, i.e. the dispersions are stable on storage.

The inks were assessed qualitatively by observation under a microscope. In parallel, a drawdown was produced on a special paper from Renolit ML. The quality of the drawdown was assessed by purely visual analysis.

Both tests were assessed on the following assessment scale with scores 1 to 4: Score 1 — very finely divided ink with high stability or very good print appearance in drawdown, very homogeneous distribution of the ink

Score 2 finely divided ink with good stability or good print appearance in drawdown, uniform distribution of the ink Score 3 ink with visible pigment particles, limited stability or unacceptable print appearance in drawdown, uneven distribution of the ink

Score 4 . separation of the pigment particles visible to the naked eye after a short time, inhomogeneous print appearance in drawdown, pigment particles visible on the paper

Table 2

The pigment preparations presented thus meet the requirements of ink-jet printing with respect to the physical and technical printing properties in an excellent manner and are thus ideally suited to applications in ink-jet printing.

Claims

Claims:

1 ) A colorant preparation comprising A) an inorganic and/or organic colorant, B) an organic solvent,

C) an aldehyde resin,

D) an alkylammonium salt of an acidic polymeric compound,

E) optionally a vinylchloride-vinylacetate copolymer,

G) optionally further standard additives for ink-jet preparations.

2) A colorant preparation as claimed in claim 1 , consisting essentially of

A) 0.1 to 50% by weight of at least one colorant selected from the group consisting of organic pigments and inorganic pigments,

B) 5 to 80% by weight of at least one organic solvent,

C) 0.1 to 50% by weight of at least one aldehyde resin,

D) 0.1 to 30% by weight of at least one alkylammonium salt of an acidic polymeric compound, E) 0 to 30% by weight of vinylchloride-vinylacetate copolymer,

F) 0 to 10% by weight of a polymeric dispersant having a molecular mass of from 1000 to 500,000 g/mol,

G) 0 to 10% by weight of further standard additives for ink-jet preparations, each percentage being based on the total weight of the colorant preparation (100% by weight).

3) A colorant preparation as claimed in claim 1 or 2, wherein the colorant is an organic pigment selected from the group consisting of monoazo, disazo, laked azo, β-naphthol, Naphtol AS, benzimidazolone, disazo condensation, azo metal complex pigment, phthalocyanine, quinacridone, perylene, perinone, thiazineindigo, thioindigo, anthanthrone, anthraquinone, flavanthrone, indanthrone, isoviolanthrone, pyranthrone, dioxazine, quinophthalone, isoindolinone, isoindoline or diketopyrrolopyrrole pigments or carbon black. 4) Colorant preparation as claimed in any one of claims 1 to 3, wherein component (B) is a compound of the formula

Rι-(0-R₂)n-0-CO-R₃ , wherein R-i, R² and R³ independently of each other are a substituted or unsubstituted, branched or straight-chain d-C₂o-alkyl- or C₃-C₂o-cycloalkyl or a substituted or unsubstituted, branched or straight-chain C₂-C₂o-alkenyl- or C₃-C₂o-cycloalkenyl, wherein the substituents are preferably 1 , 2, 3 or 4 substituents selected from the group consisting of halogen, aryl, aryl(Ci-C o)alkyl, Cs-Cβ-cycloalkyl, hetaryl, hetaryl(CrC₂o)-alkyl or Cι-C2o-alkoxy, and n is a number of from 1 to 100.

5) Colorant preparation as claimed in any one of claims 1 to 4, wherein Component C is a condensation product of urea and an aliphatic C₁-C4 aldehyde.

6) Colorant preparation as claimed in any one of claims 1 to 4, wherein Component (D) is an alkylammonium salt of phosphonopolyalkoxylates or a mixture thereof.

7) A process for producing the colorant preparations as claimed in any of claims 1 to 6, which comprises homogenizing colorant (A) together with components (B), (C), (D), and optionally (E), (F) and (G) and finely dividing with the aid of a milling or dispersing device.

8) Use of a colorant preparation as claimed in any of claims 1 to 6 for colouring high-molecular-weight organic materials of natural or synthetic origin, for example of plastics, resins, surface coatings, paints, electrophotographic toners and developers, electret materials, colour filters and of writing and printing inks and seed.

9) Use as claimed in claim 8 for coloring ink-jet inks. 10) A set of printing inks comprising printing ink preparations of black, yellow, magenta, cyan, optionally green and optionally orange colors, wherein at least one of said printing inks is or contains a colorant preparation as claimed in any of claims 1 to 8.