EP1231071B1 - Recording sheet for ink-jet printing containing copper salts - Google Patents

Abstract

Recording material for ink-jet printing comprises a carrier and an ink uptake layer containing a binder and a nanoporous inorganic oxide and also a copper salt.

Description

Technical field

The present invention relates to new stabilizers for recording materials for inkjet printing, nanoporous inorganic oxides or Contain oxide / hydroxide.

State of the art

There are essentially two different methods of inkjet printing, namely continuous and non-continuous ink jet printing.

In continuous ink jet printing, an ink jet becomes pressurized from a nozzle ejected the individual at a certain distance from the nozzle Droplet disintegrates. The individual droplets are, depending on whether an image spot to be printed or not, deflected into a collecting container or up the recording material applied. This happens e.g. B. by the reason given digital data, droplets not required are electrically charged and then deflected into the collecting container in a static electrical field become. The reverse procedure is also possible, with the uncharged Droplets are deflected into the collecting container.

In the non-continuous process, the so-called "drop on demand" the ink drop is only generated when due to the digital data Pixel must be displayed.

Today's inkjet printers have to go faster and faster for economic reasons can print. Recording materials suitable for such printers must be used therefore the inks can absorb particularly quickly. For this purpose recording materials that are nanoporous inorganic are particularly suitable Contain oxides.

Such recording materials available today do not meet all the requirements placed on them. In particular, the light resistance and the shelf life of the images produced on these materials must be improved. Such images are not particularly stable in contact with outside air, which normally contains sulfur dioxide and, especially in summer, photochemically generated impurities such as ozone and nitrogen oxides. In contact with the outside air, they are very strongly changed or even destroyed within a short period of time. These phenomena are described, for example, in the Hardcopy Supplies Journal, 6 (7), 35 (2000).

In patent application EP 0'373'573, polyhydroxybenzene derivatives are used as stabilizers proposed for recording materials for inkjet printing.

Patent application EP 0'534'634 describes the application of salt solutions which contain an at least divalent metal cation to recording materials for inkjet printing to improve the water resistance of printed images. CuCl ₂ , CuBr ₂ , Cu (NO ₃ ) ₂ , Cu (ClO ₃ ) ₂ and Cu (C ₂ H ₃ O ₂ ) _{2 are} mentioned as copper salts.

In the patent application JP 01-301'359 the addition of organic sulfonates or organic sulfates together with copper or nickel salts of monocarboxylic acids to recording materials for inkjet printing for improvement the lightfastness of printed images. As copper salts copper formate and copper acetate are mentioned by name.

To improve the stability of recording materials, the nanoporous inorganic Oxides or oxide / hydroxides are included in the patent application GB 2'088'777 derivatives of phenols and bisphenols proposed.

In patent application EP 0'685'345 a Recording material, the nanoporous inorganic oxides or oxide / hydroxides contains, the addition of dithiocarbamates, thiurams, thiocyanates or sterically hindered amines proposed.

Patent application WO 00 / 37'574 describes the addition of divalent copper, Nickel, cobalt or manganese salts of carboxylic acids with at least 4 carbon atoms to inks and also to recording materials for inkjet printing described to improve the lightfastness of printed images. In copper gluconate coating compositions were added to the examples in Table 4, the pseudo-boehmite particles with a size of less than 500 nm and contain a styrene-acrylic copolymer. The coating compositions were then poured on transparent polyethylene terephthalate films. Results regarding the durability of those made on such recording materials Images are not given.

In the patent application EP 1'034'940 a recording material is described the binder in an ink receiving layer, a porous inorganic Oxide and water-soluble polyvalent metal ions, u. a. also copper (II) ions contains.

All of these proposed additives improve the stability of recording materials for inkjet printing, mostly nanoporous inorganic oxides or contain oxide / hydroxide, probably with regard to water resistance and light resistance, in contact with contaminated outside air but not or in insufficient Extent.

In the patent application EP 1'197'345 the addition of unsubstituted or substituted 1,3-cyclohexanedione to recording materials for inkjet printing, which contain porous inorganic oxides or oxide / hydroxides for Improve the durability of printed images in contact with contaminated ones Outside air described.

The additives proposed there improve the stability of recording materials for inkjet printing, nanoporous inorganic oxides or Contain oxide / hydroxide, but not in contact with contaminated outside air sufficient extent.

Stabilizing additives for such recording materials, the nanoporous inorganic Containing oxides or oxide / hydroxides must be sufficiently soluble and with the other components of the mostly aqueous coating compositions be well tolerated. They must be colorless or at most lightly colored his. Likewise, the additives in the recording material have to be used for a long time Maintain quality and also with longer storage of the recording material or the pictures made on it do not become ineffective or yellow. Further they must be non-toxic and harmless.

There is therefore a need in recording materials that are nanoporous contain inorganic oxides or oxide / hydroxides, in addition to the ink absorption capacity, ink absorption speed, image quality, water resistance, the light resistance etc. especially the shelf life in contact with Outside air, the impurities such as ozone, nitrogen oxides or Can contain sulfur dioxide to improve.

Summary of the invention

The aim of the invention is to provide recording materials with improved Shelf life in contact with outside air, the nanoporous inorganic Contain oxides or oxide / hydroxides, in which the image recorded thereon in Supervision or review is considered and which one carrier and at least an ink receiving layer thereon.

It has now been found that the addition of certain salts of monovalent copper not only the light resistance, but surprisingly also the shelf life of recording materials for inkjet printing, the nanoporous contain inorganic oxides or oxide / hydroxides when in contact with contaminated Outside air significantly improved. The on such recording materials according to the invention produced pictures show in contact with outside air that Contaminants such as ozone, nitrogen oxides or sulfur dioxide contains, significantly fewer color changes and / or color losses than the corresponding ones Images on recording media that do not contain such additives.

The recording materials according to the invention for inkjet printing contain in the applied layers in addition to the nanoporous inorganic Oxide or oxide / hydroxide and the salts of monovalent copper one or more Binder. The salts of monovalent copper can be in the ink receiving layer, which contains the nanoporous inorganic oxide or oxide / hydroxide, be introduced, or in another layer of the recording material.

In addition to the salts of monovalent copper, it is also advantageous to use unsubstituted ones or substituted 1,3-cyclohexanedione in the recording material contribute.

Detailed description of the invention

The invention describes a recording material for inkjet printing, the has one or more layers on a carrier which, in addition to at least a nanoporous inorganic oxide or oxide / hydroxide and binders in an ink receiving layer, the salts copper (I) chloride, copper (I) bromide or Contain copper (l) sulfite monohydrate of monovalent copper. The nanoporous inorganic oxide or oxide / hydroxide and the salts of monovalent copper can be contained in the same or in different layers.

Copper (I) chloride is particularly preferred as the salt of monovalent copper.

Such a recording material contains one or more of the compounds mentioned above. Their amount is 1 mg to 1,000 mg / m ² , preferably 10 mg to 200 mg / m ^{2, of} these compounds.

worin in der Formel lb (Enolatform)

M

für ein Wasserstoffkation, ein Metallkation wie Li, Na oder K, ein Triethanolaminkation oder ein Ammoniumkation steht, das gegebenenfalls einen oder mehrere Alkylreste oder substituierte Alkylreste mit jeweils 1 bis 18 C-Atomen aufweist;

R₁

für Wasserstoff, einen Alkylrest mit 1 bis 12 C-Atomen oder einen substituierten Alkylrest mit 2 bis 6 C Atomen steht, wobei die Substituenten aus der Gruppe bestehend aus CN, COOH, OH und COOR₄ ausgewählt werden, worin R₄ für einen Alkylrest mit 1 bis 12 C-Atomen steht

und

R₂, R₃

unabhängig voneinander für Wasserstoff, einen Alkylrest mit 1 bis 6 C-Atomen oder einen substituierten Alkylrest mit 2 bis 6 C Atomen stehen, wobei die Substituenten aus der Gruppe bestehend aus CN, COOH, OH und COOR₅ ausgewählt werden, worin R₅ für einen Alkylrest mit 1 bis 12 C-Atomen steht.

It is particularly preferred if, in addition to the salts of monovalent copper, compounds of the formulas la (diketone form) and lb (enol form), as described in patent application EP 1'197'345, are used for recording materials for inkjet printing which are nanoporous contain inorganic oxide or oxide / hydroxide, are added,

where in the formula lb (enolate form)

M

represents a hydrogen cation, a metal cation such as Li, Na or K, a triethanolamine cation or an ammonium cation which may have one or more alkyl radicals or substituted alkyl radicals each having 1 to 18 carbon atoms;

R ₁

represents hydrogen, an alkyl radical having 1 to 12 carbon atoms or a substituted alkyl radical having 2 to 6 carbon atoms, the substituents being selected from the group consisting of CN, COOH, OH and COOR ₄ , in which R _{4 is} an alkyl radical having 1 to 12 carbon atoms

and

R ₂ , R ₃

independently of one another represent hydrogen, an alkyl radical having 1 to 6 carbon atoms or a substituted alkyl radical having 2 to 6 carbon atoms, the substituents being selected from the group consisting of CN, COOH, OH and COOR ₅ , in which R _{5 is} a Alkyl radical having 1 to 12 carbon atoms.

Preferably 50 mg to 600 mg / m ^{2 of} these compounds are added to the recording material.

Colloidal silicon dioxide, colloidal aluminum oxide or colloidal aluminum oxide / hydroxide can be used as the nanoporous inorganic oxide or oxide / hydroxide. Colloidal aluminum oxide, colloidal aluminum oxide / hydroxide or positively charged silicon dioxide are preferred. Particularly preferred as colloidal aluminum oxide is γ-Al ₂ O ₃ and as colloidal AIOOH AIOOH reacted with rare earth salts, as has been described in patent application EP 0'875'394. This nanoporous aluminum oxide / hydroxide contains one or more elements of atomic number 57 to 71 of the Periodic Table of the Elements, preferably in an amount between 0.4 and 2.5 mole percent based on Al ₂ O ₃ . Particularly preferred as nanoporous aluminum oxide / hydroxide is pseudo-boehmite, an agglomerate of aluminum oxide / hydroxide of the formula Al ₂ O ₃ • n H ₂ O (n = 1 to 1.5), or pseudo-boehmite reacted with rare earth salts, as well has been described in patent application EP 0'875'394. This nanoporous pseudo-boehmite contains one or more elements of atomic number 57 to 71 of the Periodic Table of the Elements, preferably in an amount between 0.4 and 2.5 mole percent based on Al ₂ O ₃ .

With ink-receiving layers for inkjet printing, it has been found that only the addition of nanoporous substances, their means of the BET isotherm determined pore volume ≥ 20 ml / 100 g, the uptake rate and significantly increases the absorption capacity of aqueous inks. Only those inorganic oxides or oxide / hydroxides should be considered "nanoporous".

The recording material can be in addition to the nanoporous inorganic oxides or oxide / hydroxides, in addition, other ones which are not nanoporous according to the above definition, contain inorganic oxides or oxide / hydroxides.

The recording material can also have several different nanoporous materials inorganic oxides or oxide / hydroxides in the same or different Layers included. A particularly favorable combination is with salts AIOOH in a lower layer and positively charged of rare earths Silicon dioxide in an upper layer.

The binders are generally water-soluble polymers. Particularly preferred are film-forming polymers.

The water-soluble polymers include e.g. B. natural or made therefrom modified compounds such as albumin, gelatin, casein, starch, gum arabic, Sodium or potassium alginate, hydroxyethyl cellulose, carboxymethyl cellulose, α-, β- or γ-cyclodextrin etc. When one of the water soluble polymers is gelatin all known types of gelatin can be used, such as acidic Pig skin gelatin or alkaline bone gelatin, acid or base hydrolyzed Gelatins, as well as substituted gelatins, e.g. B. phthalated, acetylated or carbamoylated gelatin, or gelatin reacted with trimellitic anhydride.

A preferred natural binder is gelatin.

Synthetic binders can also be used and include, for example Polyvinyl alcohol, polyvinyl pyrrolidone, fully or partially saponified Compounds of copolymers of vinyl acetate and other monomers; homopolymers or copolymers of unsaturated carboxylic acids such as (meth) acrylic acid, Maleic acid, crotonic acid, etc .; Homopolymers or copolymers from sulfonated Vinyl monomers such as B. vinyl sulfonic acid, styrene sulfonic acid, etc. Homopolymers or copolymers of vinyl monomers of (Meth) acrylamide; Homopolymers or copolymers of other monomers with ethylene oxide; polyurethanes; polyacrylamides; water soluble nylon polymers; Polyester; polyvinyl lactams; Acrylamide polymers; substituted polyvinyl alcohol; polyvinyl; Polymers of alkyl and sulfoalkyl acrylates and methacrylates; hydrolysed polyvinyl acetates; polyamides; polyvinylpyridines; polyacrylic acid; Copolymers with maleic anhydride; polyalkylene oxides; Copolymers with methacrylamide and copolymers be used with maleic acid. All of these polymers can also be used as Mixtures are used.

Preferred synthetic binders are polyvinyl alcohol and polyvinyl pyrrolidone or their mixtures.

These polymers can be made with water-insoluble natural or synthetic high molecular weight compounds are mixed, especially with acrylic latices or styrene acrylic latices.

Although water-insoluble binders are not explicitly claimed, they should water-insoluble polymers are nevertheless regarded as a system component.

The above-mentioned polymers with crosslinkable groups can be prepared using a Crosslinker or hardener converted into practically water-insoluble layers become. Such crosslinks can be covalent or ionic. The networking or hardening of the layers allows a change in the physical layer properties, such as fluid intake, or resistance against shift injuries.

The crosslinkers and hardeners become water-soluble on the basis of the crosslinked Polymers selected.

Organic crosslinkers and hardeners include e.g. B. aldehydes (such as formaldehyde, Glyoxal or glutaraldehyde); N-methylol compounds (such as dimethylol urea or methylol-dimethylhydantoin); Dioxanes (such as 2,3-dihydroxydioxane); reactive vinyl compounds (such as 1,3,5-trisacryloyl-hexahydro-s-triazine or bis- (vinylsulfonyl) methyl ether), reactive halogen compounds (such as 2,4-dichloro-6-hydroxy-s-triazine); epoxides; aziridines; Carbamoyl pyridine compounds or mixtures two or more of these crosslinkers mentioned.

Inorganic crosslinkers and hardeners include, for example, chrome alum, aluminum alum or boric acid.

The layers can also contain reactive substances that act of UV light, electron beams, X-rays or heat the layers network.

The layers can be further modified by adding fillers. Possible fillers are e.g. B. kaolin, Ca or Ba carbonates, silicon dioxide, titanium dioxide, Bentonite, zeolite, aluminum silicate, calcium silicate or colloidal silicon dioxide. Also inert organic particles such as plastic beads can be used. These beads can be made from polyacrylates, polyacrylamides, Polystyrene or various copolymers from acrylates and Styrene exist. The fillers are based on the intended use selected images. Some of these fillers can be transparent Materials are not used. But they can have positive effects in Have oversight materials. Very often you can achieve this with the use of such fillers a desired matt surface.

In addition to the salts according to the invention, the recording materials can of the monovalent copper contain further soluble metal salts, for example Alkaline earth or rare earth salts.

There is at least one ink-receiving layer in the recording materials according to the invention applied to a support along with any auxiliary layers.

A wide variety of carriers is known and is also used. So can all supports used in the manufacture of photographic materials are used. For example, transparent supports are used from cellulose esters such as cellulose triacetate, cellulose acetate, cellulose propionate, or cellulose acetate / butyrate, polyesters such as polyethylene terephthalate or polyethylene naphthalate, Polyamides, polycarbonates, polyimides, polyolefins, polyvinyl acetals, Polyethers, polyvinyl chloride and polyvinyl sulfones. Preferred are polyesters, especially because of polyethylene terephthalate or polyethylene naphthalate their excellent dimensional stability. With those in the photographic industry opaque supports used can, for example, baryta paper, with polyolefins coated papers, white opaque polyester such as B. Melinex® the DuPont can be used. Polyolefin-coated are particularly preferred Papers or white opaque polyester.

It is advantageous to coat these carriers, in particular polyester, with a Substrate layer to provide the adhesion of the ink receiving layers to improve the wearer. Such substrate layers are in the photographic Industry well known and includes e.g. B. terpolymers of vinylidene chloride, Acrylonitrile and acrylic acid or from vinylidene chloride, methyl acrylate and itaconic acid.

Uncoated papers of various types can also be used as supports that are great in their composition and in their properties May have differences. Pigmented papers and glossy papers can also be used, as can metal foils, for example Aluminum.

The layers can also be made from textile fiber materials, for example Polyamides, polyester, cotton, viscose and wool can be applied.

The additive according to the invention can be added to any layer of the recording material be introduced.

The ink-receiving layers according to the invention are generally made of aqueous solutions or dispersions containing all the necessary components, cast. In many cases, wetting agents are added as sprue aids to to improve the casting behavior and the layer uniformity. Next to her These compounds can also have an effect during the casting process Have an influence on the image quality and can therefore be selected accordingly become. Although such surfactant compounds in the invention are not claimed, they still form an integral part of the Invention.

It is also possible to separate the salts of monovalent copper in a separate process on the recording material containing nanoporous inorganic oxides, applied.

In addition to the constituents already mentioned, the inventive ones Recording materials contain additional compounds to its properties continue to improve, such as optical brighteners for improvement the degree of whiteness, such as stilbenes, coumarins, triazines, oxazoles or others compounds known to those skilled in the art.

To improve the light fastness, UV absorbers such as 2-hydroxybenztriazoles, 2-hydroxybenzophenones, triazine derivatives or cinnamic acid derivatives can be added. The amount of the UV absorber is 200-2000 mg / m ² , preferably 400-1000 mg / m ² . The UV absorber can be introduced into each layer of the recording material according to the invention, but it is particularly advantageous if it is introduced into the top layer.

It is further known that the images produced in ink jet printing are produced by the Addition of radical scavengers, stabilizers, reducing agents and antioxidants can be protected. Examples of such compounds are sterically hindered Phenols, sterically hindered amines, chromanols, ascorbic acid, phosphinic acids and their derivatives, sulfur-containing compounds such as sulfides, mercaptans, Thiocyanates, thioamides or thioureas.

The compounds mentioned can be added to the casting solutions as aqueous solutions be added. If the compounds are not sufficiently water soluble, can be introduced into the casting solutions by other known methods become. For example, the compounds can be mixed with water organic solvents such as lower alcohols, glycols, ketones, esters or amides can be dissolved. It is also possible for the compounds to be fine-grained Dispersions, as oil emulsions, as cyclodextran inclusion compounds or as latex, which contains the compound, in the casting solution.

The recording material according to the invention normally has a dry layer thickness from 0.5 to 100 µm, but especially from 5 to 50 µm.

The casting solutions can be applied to the carrier in various ways become. The casting processes include, for example, extrusion casting, the Air knife casting, the slot casting, the cascade casting and the curtain casting. The casting solutions can also be applied using a spray process. The ink-receiving layers can consist of several individual layers, which can be applied individually one after the other or together. A carrier can also be coated on both sides with ink absorption layers. It is also possible to have an antistatic layer or a layer on the back Apply improvement of flatness. The chosen casting process limits the invention in any way.

It is also possible to dip the salts of monovalent copper into one Recording material in a solution of the salt of monovalent copper in the Introduce recording material or spray it on, for example with Using an inkjet printer.

Inks for ink jet printing consist essentially of a liquid Carrier substance and a dye or pigment dissolved or dispersed therein. The liquid vehicle for ink jet printing inks is general Water or a mixture of water and a water-miscible solvent such as ethylene glycol, higher molecular weight glycols, glycerin, Dipropylene glycol, polyethylene glycol, amides, polyvinylpyrrolidone, N-methylyrrolidone, Cyclohexylpyrrolidone, carboxylic acids and their esters, ethers, alcohols, organic Sulfoxides, sulfolane, dimethylformamide, dimethyl sulfoxide, cellosolve, polyurethanes, Acrylates etc.

The non-aqueous ink components generally serve as humectants, auxiliary solvents, Viscosity regulator, penetrant or drying accelerator. The organic compounds mostly have a boiling point that is above that of water. Inks for continuous inkjet printing can go further contain inorganic or organic salts to increase conductivity. Examples of such salts are nitrates, chlorides, phosphates and the water-soluble ones Salts of water-soluble organic acids such as acetates, oxalates and citrates. The Dyes or pigments used to manufacture the together with the Inks can be used for recording materials can contain practically all known classes of these colored compounds. Typical examples of dyes or pigments used are in the patent application EP 0 559 324 listed. The recording materials according to the invention can be used with almost all state of the art inks become.

In addition, the inks can contain other additives such as surface-active Substances, optical brighteners, UV absorbers, light stabilizers, preservatives, Precipitants such as multi-charged metal compounds and polymers Links.

The salts of monovalent copper mentioned above can also be used in the inks be introduced.

The description of the inks is for illustration only and is related to the invention in no way restrictive.

The present invention is described in more detail by the following examples, without being restricted in any way.

Examples Comparative Example C-1 Preparation of the casting solution

85.5 g Disperal® (aluminum oxide / hydroxide, available from CONDEA GmbH, Hamburg, Germany) became more aqueous in 220 g at a temperature of 40 ° C Lactic acid solution (0.7%) was dispersed and then 76.95 g of a solution of polyvinyl alcohol (10%, degree of hydrolysis 98-99%, molecular weight 85,000 up to 146,000, available from ALDRICH Chemie, Buchs, Switzerland). The The final weight of the casting solution was adjusted to 449.7 g with deionized water and sonicated the solution for 3 minutes.

molding

149.9 g / m ^{2 of} this casting solution were applied to a polyethylene-coated paper support at 40 ° C. and the coated support was then dried at 30 ° C. for 60 minutes. 1 m ² of the cast support contains, in addition to the other casting additives, 22.2 g of nanoporous inorganic oxide, calculated as Al ₂ O ₃ , and 2.56 g of polyvinyl alcohol.

example 1 Preparation of the casting solution

The casting solution from Comparative Example C-1 was at a temperature of 40 ° C 0.3 g CuCI (available from Fluka Chemie AG, Buchs, Switzerland) as a solid substance added.

molding

150 g / m ^{2 of} this casting solution were applied to a polyethylene-coated paper support at 40 ° C. and the cast support was then dried at 30 ° C. for 60 minutes. 1 m ² of the cast carrier contains, in addition to the other casting additives, 22.2 g of nanoporous inorganic oxide, calculated as Al ₂ O ₃ , 2.56 g of polyvinyl alcohol and 100 mg of CuCl.

Comparative Example C 2 Production of aluminum oxide / hydroxide doped with lanthanum (2.2 mol percent based on Al ₂ O ₃ )

50 g of the aluminum oxide / hydroxide Disperal® were dispersed with good mechanical stirring at 20 ° C. in 948 g bidistilled water for 15 minutes. The temperature was then raised to 90 ° C. and stirring was then continued at this temperature for 15 minutes. Then 2.04 g of LaCl ₃ (available from Fluka Chemie AG, Buchs, Switzerland) was added as a solid and stirring was continued for 120 minutes. The solid was filtered off, washed three times with bidistilled water and dried at 110 ° C.

Preparation of the casting solution

In the casting solution from comparative example C-1, the equal amount of alumina / hydroxide doped with lanthanum used.

molding

149.9 g / m ^{2 of} this casting solution were applied to a polyethylene-coated paper support at 40 ° C. and the coated support was then dried at 30 ° C. for 60 minutes. 1 m ² of the cast support contains, in addition to the other casting additives, 22.2 g of nanoporous inorganic oxide, calculated as Al ₂ O ₃ , and 2.56 g of polyvinyl alcohol.

Example 2 Preparation of the casting solution

The casting solution from Comparative Example C-2 was at a temperature of 40 ° C 0.3 g CuCI added as a solid.

molding

150 g / m ^{2 of} this casting solution were applied to a polyethylene-coated paper support at 40 ° C. and the cast support was then dried at 30 ° C. for 60 minutes. 1 m ² of the cast carrier contains, in addition to the other casting additives, 22.2 g of nanoporous inorganic oxide, calculated as Al ₂ O ₃ , 2.56 g of polyvinyl alcohol and 100 mg of CuCl.

Comparative Example C-3 Preparation of the casting solution

The casting solution from Comparative Example C-2 was adjusted to a final weight of 447 g and then 3 g of a solution (10%) of CuSO ₄ (available from Fluka Chemie AG, Buchs, Switzerland) were added at a temperature of 40 ° C.

molding

150 g / m ^{2 of} this casting solution were applied to a polyethylene-coated paper support at 40 ° C. and the cast support was then dried at 30 ° C. for 60 minutes. 1 m ² of the cast carrier contains, in addition to the other casting additives, 22.2 g of nanoporous inorganic oxide, calculated as Al ₂ O ₃ , 2.56 g of polyvinyl alcohol and 100 mg of CuSO ₄ .

Comparative Examples C 3a to C - 3e Production of the casting solutions

3 g of the metal salt solutions listed in Table 1 (10%) were added to the casting solution from Comparative Example C-3 at a temperature of 40 ° C. instead of the solution of copper (II) sulfate: Comparative example substance C - 3a ZnCl ₂ C - 3b FeCl ₃ C - 3c FeSO ₄ C - 3d Ni (NO ₃ ) ₂ C - 3e Zr (SO ₄ ) ₂ ZnCl ₂ , FeCl ₃ , FeSO ₄ and Ni (NO ₃ ) ₂ are available from Fluka Chemie AG, Buchs, Switzerland. Zr (SO ₄ ) ₂ is available from ALDRICH Chemie, Buchs, Switzerland.

Fonts

150 g / m ^{2 of} each of these casting solutions were applied to a polyethylene-coated paper support at 40 ° C., and the coated support was then dried at 30 ° C. for 60 minutes. In addition to the other casting additives, 1 m ² of the cast carrier each contains 22.2 g of nanoporous inorganic oxide, calculated as Al ₂ O ₃ , 2.56 g of polyvinyl alcohol and 100 mg of the corresponding metal salt.

Example 4 Preparation of the casting solution

The casting solution from Comparative Example C-2 was at a temperature of 40 ° C 0.3 g CuCI (available from Fluka Chemie AG, Buchs, Switzerland) and 600 mg Cyclohexanedione (available from Acros Organics, Geel, Belgium), both as solid substances, added.

molding

150 g / m ^{2 of} this casting solution were applied to a polyethylene-coated paper support at 40 ° C. and the cast support was then dried at 30 ° C. for 60 minutes. 1 m ² of the cast carrier contains, in addition to the other casting additives, 22.2 g of nanoporous inorganic oxide, calculated as Al ₂ O ₃ , 2.56 g of polyvinyl alcohol, 100 mg of CuCl and 200 mg of cyclohexanedione.

Comparative Example C-5 Production of an aqueous dispersion of positively charged silicon dioxide

60 g of Aerosil® 200 (available from DEGUSSA AG, Frankfurt / Main, Germany) were dispersed at a temperature of 25 ° C. with stirring in 216 g of aqueous acetic acid (2.87%) with stirring using ultrasound. Thereafter, 9.86 g of an aqueous aluminum chlorohydrate solution (47.7%, made from aluminum chlorohydrate of the formula Al ₂ (OH) ₅ Cl • 2.5 H ₂ O, which is available as Locron® from Clariant AG, Muttenz, Switzerland) were added and it was 3 hours touched. The final weight was then set to 300 g.

Preparation of the casting solution

60 g of this aqueous dispersion of positively charged silicon dioxide were added a temperature of 40 ° C with stirring, diluted with 4.6 g of water and with 30.4 g of a solution of polyvinyl alcohol (10%) mixed. The solution was after setting the final weight with deionized water to 100 g with ultrasound treated.

molding

100 g / m ^{2 of} this casting solution were applied to a polyethylene-coated paper support at 40 ° C., and the coated support was then dried at 30 ° C. for 60 minutes. 1 m ² of the cast carrier contains, in addition to the other casting additives, 12 g of positively charged silicon dioxide and 2.28 g of polyvinyl alcohol.

Example 5 Preparation of the casting solution

100 g of the casting solution from Comparative Example C-5 were added at one temperature from 40 ° C with stirring 50 mg CuCI added as a solid.

molding

100 g / m ^{2 of} this casting solution were applied to a polyethylene-coated paper support at 40 ° C., and the coated support was then dried at 30 ° C. for 60 minutes. 1 m ² of the cast carrier contains, in addition to the other casting additives, 12 g of positively charged silicon dioxide, 2.28 g of polyvinyl alcohol and 50 mg of CuCI.

Comparative Example C 6 Preparation of an aqueous dispersion of aluminum oxide

96.6 g of Alu C® (96.6% content of Al ₂ O ₃ , available from DEGUSSA AG, Frankfurt / Main, Germany) were dispersed with ultrasound at 50 ° C. with stirring in 507.5 g of aqueous acetic acid (3.45%). After 30 minutes the weight was adjusted to 700 g with deionized water.

Preparation of the casting solution

58 g of this aqueous dispersion of Al ₂ O ₃ were diluted with 10.5 g of deionized water with stirring and mixed with 23.2 g of a solution of polyvinyl alcohol (7.5%). After adjusting the final weight with deionized water to 100 g, the solution was treated with ultrasound.

molding

125 g / m ^{2 of} this casting solution were applied to a polyethylene-coated paper support at 40 ° C. and then the coated support was dried at 30 ° C. for 60 minutes. 1 m ² of the cast support contains, in addition to the other casting additives, 18.13 g of Al ₂ O ₃ and 2.28 g of polyvinyl alcohol.

Example 6 Preparation of the casting solution

100 g of the casting solution from Comparative Example C-6 were added at one temperature from 40 ° C with stirring 80 mg of CuCI added as a solid.

molding

125 g / m ^{2 of} this casting solution were applied to a polyethylene-coated paper support at 40 ° C. and then the coated support was dried at 30 ° C. for 60 minutes. 1 m ² of the cast carrier contains, in addition to the other casting additives, 18.13 g of Al ₂ O ₃ , 2.28 g of polyvinyl alcohol and 100 mg of CuCl.

Example 7 Lower class

The bottom layer is identical to the cast layer of Example 2.

Preparation of the casting solution for the upper layer

To 60 g of the aqueous dispersion of positively charged silicon dioxide from example C - 5 were 1,154 g at a temperature of 40 ° C with good stirring 1,3-cyclohexanedione added. Then 18.4 g of a solution of polyvinyl alcohol (10%) added. The solution was made up with deionized water Final weight set to 100 g.

Upper layer

24 g / m ^{2 of} this casting solution were poured onto the lower layer.

molding

1 m ^{2 of} the cast carrier contains a total of 25.08 g of nanoporous inorganic oxides, 100 mg of CuCI and 277 mg of cyclohexanedione.

The following procedure was used to determine resistance to outside air and the lightfastness of the recording materials described here used:

1. Outdoor air resistance

The recording materials according to the invention were printed using an inkjet printer EPSON STYLUS ™ COLOR 750 in PQ glossy film mode (720 dpi) with original inks Gray fields with an approximate density of 1.60 with the Printed in three colors black.

The printed samples were in average daylight from 1000 - 2000 lux open on a table with moderate circulation of outside air during Left for 2 weeks. The loss of density due to exposure to light alone is very small with this amount of light.

The density loss of the cyan dye was determined using an X-Rite® densitometer measured behind a red filter. It is expressed as a percentage loss in density of the Teal indicated from the original density.

2. Lightfastness

The recording materials according to the invention were printed using an inkjet printer EPSON STYLUS ™ COLOR 750 in PQ glossy film mode (720 dpi) with original inks. Color fields of approximate density 1.60 in colors Dark purple, dark teal and blue, and color swatches of the approximate ones Density 0.50 printed in light purple and light teal.

The printed samples were irradiated in an Atlas Ci35A Weather-O-Meter® with a 6500 W xenon lamp until 40 kJoules / cm ^{2 were} reached.

The densities of the color fields were measured before and after the irradiation with an X-Rite® densitometer is measured and the density loss is expressed as a percentage Loss of density given based on the original density.

Results

The density losses obtained under these test conditions for the resistance to outside air for a recording material according to the invention which contains nanoporous inorganic aluminum oxide / hydroxide Disperal® are summarized in Table 2: example Loss of color density of the cyan dye in% 1 25 C - 1 41

It can be seen immediately from the results in Table 2 that the recording material for inkjet printing, the nanoporous aluminum oxide / hydroxide Disperal® and the additive copper (I) chloride according to the invention contains (Example 1), shows much lower density losses of the cyan dye than the corresponding recording material which contains no such additive (Comparative Example C-1).

Even after 5 months of storage under these conditions, the density is lost of the cyan dye in the recording material that the inventive Addition of copper (I) chloride, still much lower than in the recording material, that does not contain such an addition.

The density losses obtained under these test conditions for the resistance to outside air for recording materials according to the invention which contain lanthanum-modified nanoporous aluminum oxide / hydroxide are summarized in Table 3: example Loss of color density of the cyan dye in% 2 23 4 8th C - 2 40 C - 3 30 C - 3a 44 C - 3b 55 C - 3c 54 C - 3d 40 C - 3e 41

The results in Table 3 can be seen immediately that the recording material for inkjet printing, the nanoporous lanthanum modified Aluminum oxide / hydroxide and copper (I) chloride as an additive according to the invention contains (Example 2), much lower density losses of the cyan dye shows as the corresponding recording material that no such addition contains (comparative example C-2). The density loss is particularly low, though the recording material according to the invention additionally cyclohexanedione contains (Example 4).

From the results in Table 3 it can further be seen that the recording material for inkjet printing, the nanoporous lanthanum modified Contains aluminum oxide / hydroxide and the additive copper (II) sulfate (comparative example 3), significantly lower density losses of the cyan dye shows as the corresponding recording material, the other in the patent application Salts mentioned in EP 0'534'634 (Comparative Examples C - 3a to C - 3e).

The density losses obtained under these test conditions for the resistance to outside air for a recording material according to the invention which contains positively charged silicon dioxide are summarized in Table 4: example Loss of color density of the cyan dye in% 5 25 C - 5 40

The results in Table 4 can be seen immediately that the recording material for inkjet printing, the nanoporous positively charged Contains silicon dioxide and copper (I) chloride as an additive according to the invention (example 5), shows much lower density losses of the cyan dye than the corresponding one Recording material that contains no such additive (comparative example C - 5).

The density losses obtained under these test conditions for the resistance to outside air for a recording material according to the invention which contains nanoporous Al ₂ O ₃ are summarized in Table 5: example Loss of color density of the cyan dye in% 6 24 C - 6 45

It can be seen immediately from the results in Table 5 that the recording material for inkjet printing, which contains nanoporous Al ₂ O ₃ and copper (I) chloride as an additive according to the invention (Example 6), shows much lower density losses of the cyan dye than the corresponding recording material, that contains no such additive (Comparative Example C-6).

The density losses obtained under these test conditions for the resistance to outside air for a double-layer recording material according to the invention which contains nanoporous lanthanum-modified aluminum oxide / hydroxide and nanoporous positively charged silicon dioxide are listed in Table 6: example Loss of color density of the cyan dye in% 12 1

The result in Table 6 shows immediately that the recording material for inkjet printing, the nanoporous lanthanum modified Aluminum oxide / hydroxide and nanoporous positively charged silicon dioxide and as Addition of copper (I) chloride according to the invention and additionally cyclohexanedione contains, shows practically no loss of density of the cyan dye.

Even after 8 weeks of storage, the density loss of the cyan dye is with this recording material only 4%. The corresponding recording material, which probably contains the same amount of CuCI but no cyclohexanedione, exhibits a density loss of the cyan dye of 41%. The corresponding Recording material that is not CuCI, but the same amount of cyclohexanedione contains, has a density loss of the cyan dye of 55%. The corresponding recording material without CuCI and without cyclohexanedione a loss in density of the cyan dye of 60%.

The density losses for the light resistance obtained under these test conditions for a recording material according to the invention which contains nanoporous inorganic aluminum oxide / hydroxide Disperal® are summarized in Table 7: example Percent density loss Light purple Dark purple Light teal Dark teal Blue behind red filter Blue behind green filter 1 8th 5 14 6 4 8th C - 1 29 24 46 32 31 35

The results in Table 7 can be seen immediately that the recording material for inkjet printing, the nanoporous aluminum oxide / hydroxide Disperal® and the additive copper (I) chloride according to the invention contains (Example 1), shows much lower density losses in all color fields than that Corresponding recording material which contains no such additive (comparative example C - 1).

The density losses for the light resistance obtained under these test conditions for recording materials according to the invention which contain lanthanum-modified nanoporous aluminum oxide / hydroxide are summarized in Table 8: example Percent density loss Light purple Dark purple Light teal Dark teal Blue behind red filter Blue behind green filter 2 10 7 13 6 5 8th 4 9 6 20 8th 7 9 C - 2 24 22 45 30 30 31 C - 3 17 11 40 33 16 16 C - 3a 30 25 48 40 30 33 C - 3b 88 90 67 42 38 69 C - 3c 88 89 72 48 41 71 C - 3d 38 32 42 31 26 31 C - 3e 30 25 46 33 33 36

The results in Table 8 can immediately be seen that the recording material for inkjet printing, the nanoporous lanthanum modified Aluminum oxide / hydroxide and copper (I) chloride as an additive according to the invention contains (Examples 2 and 4), much lower density losses in all color fields shows as the corresponding recording material that no such addition contains (comparative example C-2). The additional addition of cyclohexanedione does not affect lightfastness (Example 4).

It can further be seen from the results in Table 8 that the recording material for inkjet printing, the nanoporous lanthanum modified Contains aluminum oxide / hydroxide and copper (II) sulfate as an additive (comparative example 3), shows lower density losses in all color fields than the corresponding one Recording material, the other in the patent application Salts mentioned in EP 0'534'634 (comparative examples C-3a to C-3e). This other salts even have a negative impact on light resistance.

The density losses for the light resistance obtained under these test conditions for a recording material according to the invention which contains positively charged silicon dioxide are summarized in Table 9: example Percent density loss Light purple Dark purple Light teal Dark teal Blue behind red filter Blue behind green filter 5 14 9 16 5 1 6 C - 5 62 49 28 12 17 19

The results in Table 9 can be seen immediately that the recording material for inkjet printing, the nanoporous positively charged Contains silicon dioxide and copper (I) chloride as an additive according to the invention (example 5), shows much lower density losses in all color fields than the corresponding one Recording material that contains no such additive (comparative example C - 5).

The density losses for the light resistance obtained under these test conditions for a recording material according to the invention which contains nanoporous Al ₂ O ₃ are summarized in Table 10: example Percent density loss Light purple Dark purple Light teal Dark teal Blue behind red filter Blue behind green filter 6 24 9 29 9 0 10 C - 6 57 24 52 10 10 25

The results in Table 10 can be seen immediately that the recording material for inkjet printing, which contains nanoporous Al ₂ O ₃ and copper (I) chloride as an additive according to the invention (Example 6), shows much lower density losses in all color fields than the corresponding recording material which contains no such additive (Comparative Example C-6).

Claims (9)

1. Recording sheet for ink jet printing comprising a support and having coated onto said support at least one ink-receiving layer containing binders, at least one nanoporous inorganic oxide and salts of monovalent copper, characterized in that it the salts of monovalent copper are copper(I)-chloride, copper(I)-bromide or copper(I)-sulfite monohydrate.
2. Recording sheet according to claim 1 characterized in that the salt of monovalent copper is copper(I)-chloride.
3. Recording sheet according to claims 1 and 2 characterized in that the amount of the salts of monovalent copper is from 10 mg/m² to 200 mg/m².
4. Recording sheet according to claims 1 to 3 characterized in that the recording sheet further comprises tautomeric compounds of formulas la (diketo form) and Ib (enol form)

   

   wherein in formula Ib (enol form)

   M

   represents a hydrogen cation, a metal cation or an ammonium cation optionally substituted by one or more alkyl or substituted alkyl groups each having from 1 to 18 C atoms;

   R₁

   represents hydrogen, alkyl with 1 to 12 C atoms or substituted alkyl with 2 to 6 C atoms, wherein the substituents are selected from the group consisting of CN, COOH, OH and COOR₄, where R₄ represents alkyl with 1 to 12 C atoms;

   and

   R₂, R₃

   independently represent hydrogen, alkyl with 1 to 6 C atoms or substituted alkyl with 2 to 6 C atoms, wherein the substituents are selected from the group consisting of CN, COOH, OH and COOR₅, where R₅ represents alkyl with 1 to 12 C atoms.

5. Recording sheet according to claims 1 to 4 characterized in that the nanoporous inorganic oxide is colloidal aluminium oxide, colloidal aluminium oxide/hydroxide or positively charged silicium dioxide.
6. Recording sheet according to claims 1 to 4 characterized in that the nanoporous inorganic oxide is colloidal γ-Al₂O₃ or pseudo-boehmite.
7. Recording sheet according to claims 1 to 4 characterized in that the nanoporous inorganic oxide is AIOOH or pseudo-boehmite reacted with salts of the rare earth metal series and comprising one or more of the elements of the rare earth metal series of the periodic system of the elements with atomic numbers 57 to 71 in an amount of from 0.4 to 2.5 mole percent relative to Al₂O₃.
8. Recording sheet according to claims 1 to 7 characterized in that the binder is selected from gelatine, polyvinyl alcohol and polyvinyl pyrrolidone or mixtures thereof.
9. Recording sheet according to claims 1 to 8 characterized in that the support is selected from the group consisting of coated or uncoated paper, transparent or opaque polyester or fibrous textile materials.