WO1999027024A1

WO1999027024A1 - Inorganic pigments containing pigment preparations

Info

Publication number: WO1999027024A1
Application number: PCT/EP1998/007165
Authority: WO
Inventors: Juan Gonzalez-Blanco; Werner Hoheisel; Peter-Roger Nyssen; Bernd Hauschel; Eberhard Kuckert
Original assignee: Bayer Aktiengesellschaft
Priority date: 1997-11-20
Filing date: 1998-11-10
Publication date: 1999-06-03
Also published as: JP2001524572A; EP1030895A1; AU1561399A; DE19751448A1; CA2310461A1

Abstract

The invention relates to pigment preparations containing a) solid compounds from the groups of oxides of titanium, zinc, tin, tungsten, molybdenum, nickel, bismuth, cerium, indium, hafnium, iron and/or silicon carbide, zinc sulfide, barium titanate, calcium titanate and/or silicon and/or solid silicon compounds in which silicon is available in stoichiometric surplus, with primary particles having a mean diameter of ∫500 nm, and b) at least one coloring agent which distinguishes itself from the solid compounds named under a). The inventive pigment preparations are characterized by a good resistance to light of the substrates colored with said preparations.

Description

Pigment preparations containing inorganic pigments

The invention relates to inorganic pigments, in particular pigment preparations containing silicon or silicon compounds, processes for their preparation and their use, in particular as printing inks for inkjet printing.

Aqueous colorant preparations, such as those used for ink-jet printing, contain water-soluble dyes as well as organic and inorganic color pigments and carbon blacks as colorants. Organic ink dyes, for example, generally produce strong-color prints with high brilliance in ink-jet printing, but have poorer lightfastness than color pigments. Compared to inorganic pigments, organic pigments often have the disadvantage of insufficient lightfastness and are therefore suitable for various applications. e.g. outdoors, often not usable.

In particular, improving the lightfastness is always part of many efforts in other applications of liquid colorant preparations.

It is therefore an object of the present invention to provide colored pigment preparations which, particularly in ink-jet printing, have improved light fastness with high optical density and brilliance at the same time.

There have now been found pigment preparations containing

a) solid compounds from the group of oxides of titanium, zinc. Tin. Tungsten, molybdenum, nickel, bismuth, cerium, indium, hafnium, iron and / or silicon carbide, zinc sulfide, barium titanate, calcium titanate and / or silicon and / or solid silicon compounds in which silicon is present in a stoichiometric excess, with an average diameter of the primary particles of

<500 nm. Preferably <150 nm, in particular <120 nm, b) at least one colorant which differs from the solid compounds mentioned under a),

c) optionally a dispersant and

d) optionally water.

The presence of the two components c) and d) is preferred.

Silicon or the silicon compounds of component a) have already been disclosed in the as yet unpublished DE-A-19 647 294.

Elemental silicon is amorphous or crystalline silicon, preferably crystalline silicon. The size of the silicon particles is preferably between 1 nm and 120 nm, particularly preferably between 1 nm and 70 nm, very particularly preferably between 5 nm and 50 nm. These particles preferably have a size distribution with a half width of 40 nm or less. Silicon particles with this average diameter are preferably produced by means of gas phase reaction (CVR) according to the process described in US Pat. No. 5,472,477. Production according to the other processes specified in DE-A 19 647 294 is also possible.

The term solid compounds includes solid compounds at room temperature, these are, for example, silicides, CaSi2 and / or BaSi2. The term compounds in which silicon is present in a stoichiometric excess preferably includes compounds of the formula Si _x Zj. _x with x> 0.5, preferably x> 0.7 and Z = C, N, O, Ge, Ca, Ba and Sr. The presence of other materials shifts the energetic position of the absorption edge within certain limits and modifies the shape of the edge . Si _x C μ _x or Si _x Geι_ _{x are} preferred as solid connections. In a preferred embodiment of the invention, the solid compounds in which silicon is present in a stoichiometric excess have a core-shell structure. The average diameter of the primary particles is preferably less than 120 nm, particularly preferably less than 100 nm, very particularly preferably less than 50 nm. These preferably have a particle size distribution with a half width of 40 nm or less. It is preferred that this consists of a core made of titanium nitride and a shell made of silicon, the silicon volume fraction preferably being at least 30% per particle.

In a further preferred embodiment of the invention, the silicon component a) contains shell particles in the form of a solid compound consisting of silicon and materials which are more absorbent in the red spectral range (600 nm <λ <700 nm) than those in the blue-green (400 nm <λ <550 nm) spectral range.

The production of the silicon component a) is also disclosed in DE-A-19 647 294 (p. 5, 1st paragraph of the priority text) and is the subject of this application.

In a preferred embodiment, the primary particles of the silicon component a) are spherical. They can also be in the form of aggregates or agglomerates.

The primary particles of silicon component a) can also be surrounded by an oxide layer that prevents direct aggregation of the Si primary particles, thereby preventing their agglomeration. The thickness of the oxide layer is preferably 1 nm to 300 nm, particularly preferably 10 to 100 nm. This oxide layer can be carried out, for example, by metering oxygen into the CVR reactor after the particles have been produced. The oxide layer preferably consists of SiO ₂ . The preparations according to the invention preferably contain 0.01 to 500, in particular 0.01 to 250% by weight, in particular 0.01 to 20% by weight of component a), based on the colorant of component b).

The colorants of component b) are, for example, organic and

Component a) various inorganic pigments, carbon black or water-soluble and water-insoluble dyes in question, dyes also being understood as optical brighteners.

In particular, acidic to alkaline carbon blacks from the group of furnace or gas carbon blacks and chemically or physically modified or aftertreated carbon blacks are suitable as carbon blacks, and inorganic pigments, for example zinc sulfides, ultramarine, iron oxides, cobalt blue and chromium oxide pigments, and pigments in the form of finely particulate Oxides such as silicon dioxide, titanium dioxide, nickel oxides, chromium antimony titanium dioxide, aluminum oxide and finely particulate

Metals such as copper, iron or aluminum and as organic color pigments, for example those of the azo, disazo, polyazo, anthraquinone, thioindigo series, furthermore other polycyclic pigments such as, for example, from phthalocyanine, quinacridone, dioxazin, isoindolinone, naphthalenetetracarboxylic acid and perylene and perylene tetracarboxylic acid series, furthermore those from the perinone, indigo,

Thioindigoid and diketopyrrolopyrrole series, as well as metal complex pigments of azo, azomethine or methine dyes or lacquered dyes such as Ca, Mg, Al lacquers of dyes containing sulfonic acid and / or carboxylic acid groups.

Examples of organic dyes which are soluble in water are acidic and basic dyes and those which are insoluble in water are, for example, disperse dyes or whiteners (optical brighteners). Examples of disperse dyes are those from the azo, disazo, anthraquinone, coumarin, isoindolenine, quinoline and methine series. In a preferred embodiment, the preparation according to the invention contains oxides and / or nitrides of metals as colorants which absorb more strongly in the red spectral range of 600 nm <λ <700 nm than in the blue-green spectral range of 400 nm <λ <550 nm. This applies in particular when using pigments that have a yellow to orange intrinsic color. As such additives, pigments are made

Titanium nitride with an average diameter of 1 nm to 400 nm, preferably 10 nm to 120 nm or its agglomerates are preferred. Their manufacture can e.g. according to US-A 5 472 477. Also preferred colorants are ultramarine pigments, e.g. available from Nubiola S.A. under the name Nubix® Pigments. Iron (III) hexacyanoferrate (II) is also preferred. Also preferred are pigments made of iridium oxide which are doped with tin at more than 5% by weight.

The particle size of the other representatives of component a) is preferably 1 nm to 500 nm, particularly preferably 1 nm to 120 nm. obtainable by the process described in US Pat. No. 5,472,477.

Dispersant

Dispersants are preferably molecules with a molecular weight of 1,000 to 500,000, preferably 1,000 to 100,000 and in particular 1,000 to 10,000 g / mol. The dispersants can be nonionic, anionic, cationic or amphoteric compounds.

Examples of nonionic dispersants are: alkoxylates, alkylolamides, esters, amine oxides and alkyl polyglycosides.

Other suitable nonionic dispersants are: reaction products of alkylene oxides with alkylatable compounds, such as, for example, fatty alcohols, fatty amines, fatty acids, phenols, alkylphenols, arylalkylphenols, such as styrene-phenol Condensates, carboxamides and resin acids. This is, for example

Ethylene oxide adducts from the class of reaction products of ethylene oxide with:

a) saturated and / or unsaturated fatty alcohols with 6 to 20 carbon atoms or

b) alkylphenols with 4 to 12 carbon atoms in the alkyl radical or

c) saturated and / or unsaturated fatty amines with 14 to 20 carbon atoms or

d) saturated and / or unsaturated fatty acids with 14 to 20 carbon atoms or

e) hydrogenated and / or unhydrogenated resin acids.

Suitable ethylene oxide adducts are, in particular, the alkylatable compounds mentioned under a) to e) with 5 to 120, preferably 5 to 60, in particular 5 to

30 moles of ethylene oxide in question.

Nonionic polymeric dispersants are particularly preferred.

The polymeric dispersants include, for example, the compounds mentioned in the directory “Water-Soluble Synthetic Polymers: Properties and Behavior” (Volume I + II by Philip Molyneux, CRC Press, Florida 1983/84).

Other polymeric dispersants are, for example, water-soluble and water-emulsifiable compounds, e.g. Homopolymers and copolymers, graft and

Graft copolymers and statistical block copolymers.

Particularly preferred polymeric dispersants are, for example, AB, BAB and

ABC block copolymers. In the AB or BAB block copolymers, the A segment is a hydrophobic homopolymer or copolymer, which is a compound for

Pigment ensures and the B block a hydrophilic homopolymer or copolymer or a salt thereof and ensures the dispersion of the pigment in the aqueous medium. Such polymeric dispersants and their synthesis are known for example from EP-A-518 225 and EP-A-556 649.

Further examples of suitable polymeric dispersants are polyethylene oxides,

Polypropylene oxides, polyoxymethylenes, polytrimethylene oxides, polyvinyl methyl ether, polyethyleneimines, polyacrylic acids, polyarylamides, polymethacrylic acids, polymethacrylamides, poly-N, N-dimethyl-acrylamides, poly-N-isopropylacrylamides, poly-N-acrylglycinamides, poly-N-methacrylglycinamides, polyvinyl alcohol amides Polyvinyl acetate, copolymers of polyvinyl alcohols and polyvinyl acetates, polyvinylpyrrolidone, polyvinyloxazolidones, polyvinylmethyloxazolidones.

Natural polymeric dispersants such as cellulose, starch, gelatin or their derivatives are also important as polymeric dispersants. In particular, polymers come from amino acid units e.g. Polylysine, polyaspartic acid, etc. in

Question.

Examples of anionic dispersants are: alkyl sulfates, ether sulfates, ether carboxylates, phosphate esters, sulfosucinates, sulfosuccinatamides, paraffin sulfonates, olefin sulfonates, sarcosinates, isothionates, taurates and lignin niches

Links.

Anionic, polymeric dispersants are particularly preferred.

Suitable anionic polymeric dispersants are, in particular, condensation products of aromatic sulfonic acids with formaldehyde, such as condensation products from formaldehyde and alkylnaphthalenesulfonic acids or from formaldehyde, naphthalenesulfonic acids and / or benzenesulfonic acids, condensation products from optionally substituted phenol with formaldehyde and sodium bisulfite. Also suitable are condensation products which can be obtained by reacting naphthols with alkanols, addition of alkylene oxide and at least partial conversion of the terminal hydroxyl groups into sulfo groups or half esters of maleic acid, phthalic acid or succinic acid.

Dispersants from the group of sulfosuccinic acid esters and alkylbenzenesulfonates are also suitable. In addition, sulfated, alkoxylated fatty acid alcohols or their salts. Alkoxylated fatty acid alcohols are understood in particular to be those with 5 to 120, preferably 5 to 60, in particular 5 to 30, ethylene oxide-provided C6-C ₂ fatty acid alcohols which are saturated or unsaturated, in particular stearyl alcohol. A stearyl alcohol alkoxylated with 8 to 10 ethylene oxide units is particularly preferred. The sulfated alkoxylated fatty acid alcohols are preferably present as a salt, in particular as an alkali or amine salt, preferably as a diethylamine salt.

Further examples of anionic, polymeric dispersants are the salts of polyacrylic acids, polyethylene sulfonic acids, polystyrene sulfonic acid, polymethacrylic acids, polyphosphoric acids.

Additional examples of anionic, polymeric dispersants are copolymers of acrylic monomers, which are exemplified in the following table by a combination of the following monomers, which are synthesized into random, alternating or graft copolymers:

Acrylamide, acrylic acid;

Acrylamide, acrylonitrile;

Acrylic acid, N-acrylglycinamide;

Acrylic acid, ethyl acrylate;

Acrylic acid, methyl acrylate; Acrylic acid, methylene butyrolactam;

N-acrylglycinamide, N-isopropylacrylamide; Methacrylamide, methacrylic acid;

Methacrylic acid, benzyl methacrylate;

Methacrylic acid, diphenylmethyl methacrylate;

Methacrylic acid, methyl methacrylate; Methacrylic acid, styrene.

Other anionic, polymeric dispersants are styrene maleic anhydride copolymers, their copolymers with the acrylic monomers mentioned and polymers based on polyurethane, e.g. based on star-branched oligourethanes according to EP-A 331 066 or EP-A 400 410.

Graft polymers and graft copolymers in which nonionic and / or anionogenic vinyl monomers are grafted onto a polymeric base are also suitable. Synthetic or natural protective colloids can serve as the polymeric basis.

Furthermore, lignin sulfonates are particularly suitable, e.g. those obtained by the sulfite or Kraft process. They are preferably products which are partially hydrolyzed, oxidized, propoxylated, sulfonated, sulfomethylated or disulfonated and fractionated by known methods, e.g. after this

Molecular weight or by degree of sulfonation. Mixtures of sulfite and kraft lignin sulfonates are also effective. Lignin sulfonates with an average molecular weight of greater than 1000 to 100,000, an active lignin sulfonate content of at least 80% and preferably with a low polyvalent cation content are particularly suitable. The degree of sulfonation can vary within wide limits.

Examples of cationic dispersants are: quaternary alkylammonium compounds and imidazoles.

Cationic, polymeric dispersants are particularly preferred. Examples of cationic, polymeric dispersants are the salts of polyethyleneimines, polyvinylamines, poly (2-vinylpyridines), poly (4-vinylpyridines), poly (diallyldimethyl.ammonium) chloride, poly (4-vinylbenzyltrimethylammonium) salts, poly ( 2-vinylpiperidine).

Examples of amphoteric dispersants are: betaines, glycinates, propionates and imidazolines.

Anionic and cationic polymers are summarized as polyelectrolytes and can be partially or completely dissociated in an aqueous and / or organic phase.

The dispersant used is preferably used in an amount of 0.1 to 200% by weight, in particular 0.5 to 100% by weight, based on components a) and optionally b).

If water-insoluble dyes or pigments or carbon black are used as colorants, the amount of the dispersant used preferably relates to the sum of components a) and b).

In addition to the dispersant used, the pigment preparations according to the invention may also contain further cationic, anionic, amophotere and / or nonionic and / or surface-active compounds, for example those which are listed in the "Surfactants Europe, A. Directory of surface Active

Agents available in Europe "(Edited by Gordon L. Hollis, Royal Socity of Chemistry, Cambridge (1995).

If the dispersant used contains ionic groups, these auxiliaries should preferably be non-ionic or of the same ionogenicity. In particular, the pigment preparations used as printing inks for inkjet printing preferably contain an organic solvent as further component e).

Suitable organic solvents (e) are: aliphatic Cj-C-i alcohols, such as

Methanol, ethanol, isopropanol, n-propanol, n-butanol, isobutanol or tert-butanol, 1,5-pentadiol, aliphatic ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone or diacetone alcohol, polyols, such as ethylene glycol, propylene glycol, Butylene glycol, diethylene glycol, triethylene glycol, trimethylolpropane, polyethylene glycol with an average molecular weight of 100 to 4000, preferably 400 to

1500 g / mol or glycerol, monohydroxy ether, preferably monohydroxy-alkyl ether, particularly preferably mono-Cj-Cj-alkyl glycol ether such as ethylene glycol monoalkyl, monomethyl, diethylene glycol monomethyl ether or diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol ether, dipropylene glycol ether, or monoethyl ether, also 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-pyrrolidone, N-vinyl-pyrrolidone, 1,3-dimethyl-imidazolidone, dimethylacetamide and dimethylformamide.

Mixtures of the solvents mentioned are also suitable.

The amount of the organic solvent is preferably 0 to 40, in particular 2 to 20,% by weight, based on the pigment preparations.

The amount of water and organic solvent is preferably 20 to 99% by weight, preferably 30 to 97% by weight, based on the pigment preparations.

Furthermore, the pigment preparation can contain agents for adjusting the viscosity of the ink, such as, for example, polyvinyl alcohol, polyvinyl pyrrolidone, methyl cellulose and others, agents known to those skilled in the art, provided that they do not adversely affect the stability of the printing ink, the printing behavior and the drying behavior on paper. As a further additive, compounds from the group of terpenes, terpenoids, fatty acids and fatty acid esters are mentioned. The following may be mentioned as preferred connections:

Ocimen, myrcene, geraniol, nerol, linalool, citronellol, geranial, citronellal, neral, limonene, menthol, for example (-) - menthol, menthol or bicyclic monoterpenes, saturated and unsaturated fatty acids with 6 to 22 C atoms, such as for example stearic acid, oleic acid, linoleic acid and linolenic acid or mixtures thereof.

In principle, the pigment preparations can contain further additives such as preservatives (biocides), further wetting agents or surfactants, spacers, matting agents, stabilizers, further UV absorbers, plasticizers, lubricants and, if appropriate, pH regulators.

Suitable biocides are e.g. Isothiazolones and benzisothiazolones.

Suitable spacers or matting agents have average particle diameters, in particular in the range from 0.2 μm to 30 μm, and are described, for example, in DE 3 331 542. The spacers are preferably water-insoluble and resistant to the solvent additives used in the inks. Examples of suitable spacers or matting agents are polymethyl methacrylate, polystyrene, styrene-divinylbenzene copolymer, cross-linked polymethyl methacrylate, cross-linked or uncross-linked polyvinyl toluene.

Suitable stabilizers are o-, m- and p-dihydroxybenzenes, hydroxychromanes, 5-hydroxycoumarans, spirochromanes, spiroindanes, p-alkoxyphenols, sterically hindered phenols, gallic acid derivatives, methylenedioxybenzenes, aminophenols, aminoanilines, sterically hindered amines or hydroxyl groups with phenol ester or derivatives with phenesterol phenols, derivatives with phenesterol phenols or derivatives with phenol groups or derivatives with acylated or alkylated aromatic amino groups, metal complexes. Particularly suitable stabilizers are sterically hindered amines, preferably compounds based on 2,2,6,6-tetraalkylpiperidine, particularly preferably compounds based on 2,2,6,6-tetraalkylpiperidine which have at least one covalently bound 2,2,6 , 6-tetraalkylpiperidine fragment included.

In many cases, the use of certain combinations of color image stabilizers has proven to be particularly effective.

Suitable UV absorbers are described, for example, in DE 195 03 885.

For example, core-shell latices with a soft core and a hard shell, latices which consist of a soft core and a shell made of crosslinked gelatin and with soft intermediate layers are used as plasticizers and lubricants.

Examples of pH regulators are NaOH, ammonia or aminomethylpropanol, N, N-dimethylaminoethanol.

Examples of preservatives are methyl- and chloromethyl-isothiazolin-3-one,

Benzisothiazolin-3-one or mixtures thereof.

As a further special embodiment of the invention, the pigment preparations according to the invention are to be mentioned which, in addition to components a) and b) and optionally c) and d), additionally contain sterically hindered amines, preferably those based on 2,2,6,6-tetraalkylpiperidine based on 2,2,6,6-tetraalkylpiperidine, which contain at least one covalently bound 2,2,6,6-tetraalkylpiperidine fragment.

The pigment preparations according to the invention preferably contain: 0.01 to 500% by weight, preferably 0.01 to 250% by weight, in particular 0.01 to 20% by weight of component a), based on the colorant of component b),

1 to 99.95% by weight, preferably 1 to 65% by weight, of a colorant of component b), based on the preparation,

0.1 to 200% by weight, in particular 0.5 to 100% by weight, of a dispersant of component c), based on component a), optionally based on the sum of components a) and b) and

0 to 98% by weight, in particular 0.2 to 98% by weight, particularly preferably 10 to 98% by weight, very particularly preferably 30 to 98% by weight of water, based on the pigment preparation.

The invention further relates to a process for the preparation of the pigment preparations as printing inks for inkjet printing, which is characterized in that a pigment of component a) and the colorant b), in particular if it is an organic or inorganic pigment, or a water-insoluble dye or whitener is homogenized with at least part of the dispersant c) and, if appropriate, further additives and, if appropriate, wet comminuted.

According to the invention, the preparation of the pigment preparations optionally includes a surface modification of pigments of comp. A) in water and / or polar organic solvent in order to convert the “raw pigments” obtained from the pigment production into the desired fine distribution and to deagglomerate or deaggregate them. Methods for this are described for example in EP-0 650 945 A2.

A further possibility for the deagglomeration of pigments of comp. A) consists in pretreating the pigment powders by means of dilute ammonia solution. According to the invention, pigment preparations containing component a) and pigment preparations containing pigments or water-insoluble colorants of component b) alone can first be prepared separately and then mixed to give the pigment preparation according to the invention.

In the case of the use of water-insoluble colorants of component b), the pigment of component a) is, if appropriate after surface modification, optionally together with the colorants of component b) to be used in powder form or in the form of the water-moist presscake together with at least part of the dispersant and Water, preferably deionized water, is struck into a homogeneous grinding suspension, for example by means of an agitator chest, dissolver and similar units, if appropriate after preliminary comminution (ie introduced and homogenized).

The grinding suspension can also contain fractions of low-boiling solvents (boiling point <150 ° C), which can be removed by evaporation in the course of the subsequent fine grinding. However, it can also contain proportions of higher-boiling solvents or other additives as described above, e.g. Grinding aids, defoaming agents or wetting agents.

The wet comminution of comp. A) or comp. B), or together a) + b) includes both the pre-comminution and the fine grinding. The pigment concentration of the suspension is preferably above the desired concentration of the finished pigment preparation or printing ink. The desired final pigment concentration is preferably set after the wet comminution. Following the pre-comminution, grinding is carried out to the desired particle size distribution. For this grinding, aggregates such as kneaders, roller mills, kneading screws, ball mills, rotor-stator mills, dissolvers, corundum disk mills, vibrating mills and in particular high-speed, continuously or discontinuously charged agitator ball mills with grinding media are included a Durcli knife from 0.1 to 5 mm in question. The grinding media can be made of glass, ceramic or metal, for example steel. The milling temperature is preferably in the range from 0 to 250.degree. C., but generally at room temperature, in particular below the cloud point of the dispersant of component c) and of the surfactant which may be used.

In a likewise preferred procedure, the grinding can be carried out partially or completely in a high-pressure homogenizer or in a so-called jet disperser (known from DE-A 19 536 845), as a result of which the abrasion of the grinding media in the suspension or the release of soluble substances from the grinding media (eg ions from glass bodies) can be reduced to a minimum or avoided completely.

In a dilution step, the pigment preparation obtained is mixed and homogenized in water in a manner known per se, if appropriate with the remaining amounts of dispersant and, if appropriate, further additives, and is adjusted to the desired final pigment concentration or color strength of the preparation or printing ink. If necessary, some of the dispersant can also be added here, for example in order to avoid reagglomeration of fine pigment particles in the dilution.

Of particular advantage is a process for the preparation of the pigment preparations, in which sufficient dispersant is provided for the stabilization in the grinding step for the production of the pigment concentrate. Following this or after dilution with water, dispersant and / or excess surface-active agent which is not adsorbed on the pigment is preferably removed and the desired pigment preparation is then adjusted by adding the remaining portions of the pigment preparation. One method for removing dispersant in solution is, for example, centrifuging the suspension and then decanting off the supernatant. Membrane or microfiltration processes can also be considered.

Furthermore, other additives such as e.g. Polyurethane or acrylic polymers can be added to further improve water fastness if necessary. These can be both water-soluble and water-emulsifiable, or they can be soluble in one of the components contained in b).

In a preferred procedure, the pigment preparations are mixed and homogenized using a jet disperser or high-pressure homogenizer in order to prevent the formation of foam and to avoid possible reagglomeration.

With the setting of the desired pigment preparations, the setting for the desired viscosity, color strength, hue, density and surface tension of the ink takes place.

Before using the pigment preparations as printing inks, the inks are optionally finely filtered, for example using 0.5 to 5 μm membrane or glass filters.

In general, the physical ink properties are adjusted for use in conventional inkjet printers, the surface tension preferably being between 20 and 70 mN / m and the viscosity preferably less than 20 mPa s, in particular 0.5 to 10 mPa s.

The printing inks used according to the invention and the printing inks according to the invention provide prints with excellent lightfastness and high optical density as printing ink in inkjet printing and also have the following advantages: excellent dispersion and storage stability in a wide temperature range, none

Blockage in the print head (so-called kogation or clogging), high water and Migration fastness of the prints on different substrates, eg on wood-free

Paper, medium Paper quality, sized and coated paper, polymer films, transparencies for overhead projection, no bleeding in multi-color printing, even when used together with dye inks or other pigmented inks.

The pigment preparations described above are preferably used as printing inks for inkjet printing.

Ink-jet printing is known per se and is generally carried out in such a way that the printing ink is filled into a receptacle of an ink jet print head and sprayed onto the substrate in small droplets. The droplet-shaped ink ejection is preferably carried out via a piezoelectric crystal, a heated cannula (bubble or thermo-jet process) or mechanical pressure increase, pressure being exerted on the ink system and ink droplets being thrown out in this way. The droplets from one or more small nozzles are targeted onto the substrate, e.g. Shot paper, wood, textiles, plastic or metal. The individual droplets on the substrate are combined to form characters or graphic patterns by electronic control.

A method is also possible in which the smallest volumes in the form of drops are applied to a substrate by means of electrostatic deflection from an ink jet.

The invention further relates to the use of the pigment preparations as printing inks for ink-jet printing and for pigmenting and coloring natural or synthetic materials, in particular plastics, leather and paper in the mass and surface. In particular, the pigment preparations are also suitable for the production of automotive paints, dispersion paints, dispersion paints, printing inks, water-thinnable coating systems, aqueous flexographic and gravure printing inks, wallpaper paints, aqueous wood protection systems and wood stains, plasters, and for pigmenting colored pencil leads, fiber pens, ink jet inks , Inks, pastes for pens, chalks, detergents and cleaning agents, shoe care products, non-woven nonwovens, pulp coloring, paper coating colors, cardboard printing inks, coloring of latex products, abrasives, spin dyes and foils.

The pigment preparations are particularly preferred as printing inks for the

Ink jet printing used.

Examples

Production and use of zinc oxide as light stabilizer in ink jet inks

example 1

There became a stock solution (A) (stock ink) of a magenta dye as a sodium salt of the formula

with an E 1/1 value of 12 produced by homogeneous mixing of

22.8 g of an aqueous, salt-free solution of the above-mentioned magenta dye with an E 1/1 value of 53 (pure dye content approx. 10.4% by weight) 6.2 g 1.5 Pentadiol

6.2 g of 2-pyrrolidone and

64.8 g water. (El / 1 value: extinction value of the longest wavelength band in the light spectrum, which is obtained when a 1% solution of the dye is measured in a measuring cell with a layer thickness of 1 cm.

Furthermore, a solvent mixture (B) consisting of

8.0 g of 1,5-pentanediol

8.0 g of 2-pyrrolidone

84.0 g water

manufactured.

Then were

5 g of the stock solution (A),

4.4 g of the solvent mixture (B) and

0.6 g of an aqueous zinc oxide dispersion consisting of

30% by weight of zinc oxide with a diameter of the primary particles of 10-30 nm measured by means of transmission electron microscopy (TEM) or an agglomerate particle size determined, from which the following mass distribution resulted by measurement with an ultracentrifuge. 50 mass% of particles smaller than 43 nm (d ₅₀ of 43 nm) 90 mass% of particles smaller than 65 nm (d ₅₀ of 65 nm) 10 mass% of particles smaller than 25 nm (d ₅₀ of 25 nm) less than 2% by weight of polyacrylic acid and residual water mixed homogeneously to form a printing ink, and printed by means of a thermal inkjet printer of the type HP Deskjet 500 C (from Hewlett Packard), in which the ink thus produced is transferred to the black cartridge type HP 51626 A was replaced in exchange for the ink originally contained. The ink according to the invention could be printed without problems and has very good storage stability.

Full-surface prints were made on normal paper (Agfa 701, from Agfa-Gevaert) and on ink-jet special paper (HP-Premium, from Hewlett-Packard) and then the prints were made for 12 hours with xenon light with an intensity of 750 W / m ² exposed, whereby UV light below a wavelength of 290 μm was excluded by means of a filter. The light fastness was assessed on the basis of the residual color difference DE * and the hue angle difference Hab * according to the Cielab system in comparison with the respective unexposed printout.

The results are shown in Table 1. The lower the value of the residual color difference, the better the light fastness.

Example 2

As described in Example 1, a printing ink consisting of

5 g of the stock solution (A), 2.5 g of the solvent mixture (B) and

2.5 g of the same zinc oxide dispersion as in Example 1 and printed as in Example 1 and tested.

Comparative example

As described in Example 1, a printing ink was created consisting of 5 g of the caulking solution (A) and 5 g of the solvent mixture (B) were printed and tested analogously to Example 1 without the addition of a light stabilizer.

Table 1

It was found that the dye inks produced and printed according to Examples j_ and 2 have a significantly improved light fastness.

Claims

claims

1. Containing pigment preparations

a) solid compounds from the group of oxides of titanium, zinc, tin,

Tungsten, molybdenum, nickel, bismuth, cerium, indium, hafnium, iron and / or silicon carbide, zinc sulfide, barium titanate, calcium titanate and / or silicon and / or solid silicon compounds, in which silicon is present in a stoichiometric excess, with an average diameter of the primary particles of <500 nm, and

b) at least one F-colorant which differs from the compounds mentioned under a).

2. Pigment preparations according to claim 1, containing

a) silicon and / or solid silicon compounds in which silicon is present in a stoichiometric excess, with an average diameter of the primary particles of <120 nm and

b) at least one colorant.

3. pigment preparations according to claim 1, containing as component a) solid compounds from the group of oxides of titanium, zinc, tin, tungsten, molybdenum, nickel, bismuth, cerium, indium, hafnium, iron and / or silicon carbide, zinc sulfide, barium titanate and / or calcium titanate with an average primary particle of <120 nm.

4. pigment prep arations according to claim 1, containing in addition to components a) and b) at least one dispersant c) and water d).

5. pigment preparations according to claim 1, characterized in that the solid compounds in which silicon is present in stoichiometric excess, compounds of the formula Si _x Zι _ _x with x> 0.5, preferably x> 0.7 and Z = C, N , O, Ge, Ca, Ba and Sr are.

6. Pigment preparations according to claim 1, characterized in that organic and inorganic pigments, carbon black or water-soluble and water-insoluble dyes or optical brighteners are used as colorants of component b).

7. Pigment preparations according to claim 1, characterized in that they additionally contain an organic solvent from the group below: aliphatic C1-C4 alcohols, such as methanol, ethanol, isopropanol, n-propanol, 1,5-pentanediol, n- Butanol, isobutanol or tert-butenol, aliphatic ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone or

Diacetone alcohol, polyols, such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, trimethylolpropane, polyethylene glycol with an average molecular weight of 100 to 4000, preferably 400 to 1500 g / mol or glycerol, monohydroxy ether, preferably monohydroxy alkyl ether, particularly preferably mono-Cι- C4-alkyl glycol ethers such as ethylene glycol monoalkyl, monomethyl, diethylene glycol monomethyl ether or diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, di-propylene glycol monoethyl ether, thiodiglycol, triethylene glycol monomethyl ether or monoethyl ether, and also 2-pyrrolidone-2-pyrrolidone pyrrolidone, N-vinyl-pyrrolidone, 1,3-dimethyl-imidazolidone, dimethylacetamide and dimethylformamide or mixtures thereof.

8. Pigment preparations according to claim 1, comprising:

0.01 to 500% by weight, preferably 0.01 to 250% by weight, in particular 0.01 to 20% by weight of component a), based on component b), 1 to 99.95% by weight, preferably 1 to 65% by weight, of a colorant of component b), based on the preparation,

0 to 200% by weight, in particular 0 to 100% by weight, of a dispersant of component c), based on component a), optionally on the sum of components a) and b) and

0 to 98 wt .-%, in particular 0.2 to 98 wt .-% water, based on the pigment preparation.

9. pigment preparations according to claim 1 additionally containing a sterically hindered amine, preferably an amine based on 2,2,6,6-tetraalkylpiperidine, particularly preferably based on 2,2,6,6-tetraalkylpiperidine, which is at least one covalent contains bound 2,2,6,6-tetraalkylpiperidine fragment.

10. Use of the pigment preparations according to claim 1 as printing inks for ink-jet printing.

11. Use of the pigment preparations according to claim 1, for pigmenting and coloring natural or synthetic materials, in particular dispersion paints, printing inks, water-thinnable coating systems and automotive paints, and for pigmenting and coloring plastics, leather and paper in the mass and surface, in particular paper coating color.

12. Use of the pigment preparations according to claim 1 for the production of printing inks for ink-jet printing.