DE60102683T2 - Improved inkjet receiving medium - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION

The The present invention relates to an improved recording element for inkjet printing.

GENERAL STATE OF THE ART

at In the majority of applications, pressure is applied by pressure contact a colored one Printing form with a printing ink receiving material in which it usually is plain paper. The most used mechanical printing technique is known as lithographic printing, the selective attraction of oleophilic color on a suitable Receiving material based.

In recently, So-called stop-free printing systems have the time Pressure contact pressure displaced to some extent for specific applications. An overview can be found e.g. in the book "Principles of Non Impact Printing "by Jerome L. Johnson (1986), Palatino Press, Irvine, CA 92715, USA.

When Non-impact printing technology has become inkjet printing due to the Simplicity of construction, practical operation and cheapest Buying into a popular one Technology enforced. Especially with limited editions of a printed matter Inkjet printing has become a preferred technology. One recent review of the Advances and trends in inkjet printing technology are being made by Hue P. Le in "Journal of Imaging Science and Technology ", Vol. 42 (1), January / February 1998, given.

In ink jet printing, tiny drops of liquid ink are injected directly onto a printing ink receiving surface and the printing device and receiving element do not physically contact each other. The printer electronically stores the print data and controls a mechanism for imagewise ejecting the drops. When printing, the printhead moves across the paper or vice versa. Too early patents on inkjet printers count US 3,739,393 . US 3,805,273 and US Pat. No. 3,891,121 ,

The Spraying the ink droplets can be done in different ways. For a first type of Injection process, the generation of a continuous droplet stream according to a pressure wave pattern. This method is known as a high pressure process. In a first embodiment, the droplet stream becomes in droplets, electrostatically charged, deflected and collected again, and in droplets, remain uncharged, continue to fly in a straight line and create the image, dissolved. In another embodiment The charged deflected droplet stream forms the picture and becomes the uncharged, undeflected stream of droplets collected again. In this variant of high-pressure ink jet method, various Distracted beams at different angles and draw like that the picture on (multiple deflection system).

To a second method the ink droplets "on demand" are generated "(" DOD "method or" drop on demand "method), wherein the printing device the droplets only emits when she to serve for imaging on a printing ink receiving material. This adds complexity charging the drops, distracting hardware and resampling the ink avoided. Drop-on-demand can be ink drop generation by a mechanical movement of a piezoelectric Transducer generated pressure wave (the so-called piezoelectric method) or by discrete heat shocks (the so-called "bubble Jet "method or" Thermal Jet "method) become.

• – wässrige Tintenzusammensetzungen : der Trocknungsmechanismus umfasst Absorption, Durchdringung und Verdampfung,
• – ölige Tintenzusammensetzungen : der Trocknungsmechanismus umfasst Absorption und Durchdringung,
• – Tintenzusammensetzungen auf Lösungsmittelbasis : die Trocknung beruht hauptsächlich auf Verdampfung,
• – Heißschmelz- oder Phasenwechseltintenzusammensetzungen : das Bindemittel der Tinte ist flüssig bei Ausstoßtemperatur, aber fest bei Zimmertemperatur, keine Trocknung aber Erstarrung,
• – UV-härtbare Tintenzusammensetzungen : keine Trocknung aber Polymerisation.

Inkjet printing ink compositions typically contain the following ingredients: dyes or pigments, water and / or organic solvents, humectants such as glycols, detergents, thickeners, polymeric binders, preservatives, etc. It should be noted that the optimum composition of such an ink is the one used Ink jet printing method and depends on the type of substrate to be printed. Ink compositions can be broadly divided into the following categories

• Aqueous ink compositions: the drying mechanism includes absorption, permeation and evaporation,
• Oily ink compositions: the drying mechanism includes absorption and permeation,
• Solvent-based ink compositions: the drying is mainly based on evaporation,
• Hot melt or phase change ink compositions: the binder of the ink is liquid at ejection temperature but solid at room temperature, no drying but solidification,
• UV-curable ink compositions: no drying but polymerization.

• – die Drucktinte aufnehmende Schicht soll ein hohes Drucktinte absorbierendes Vermögen aufweisen, so dass die Punkte nicht ausfließen und sich nicht mehr als notwendig ausbreiten werden, um eine hohe optische Dichte zu erhalten,
• – die Drucktinte aufnehmende Schicht soll eine hohe Drucktinte absorbierende Geschwindigkeit (kurze Tintentrocknungszeit) aufweisen, so dass die Tintentröpfchen nicht auslaufen werden, wenn sie sofort nach Aufspritzen verschmiert werden,
• – die auf die Drucktinte aufnehmende Schicht aufgetragenen Tintenpunkte sollen eine wesentlich runde Form aufweisen und eben am Umfang sein. Der Punktdurchmesser muss konstant und genau gesteuert werden,
• – die Drucktinte aufnehmende Schicht muss schnell angefeuchtet werden, um "Puddeln" zu vermeiden, d.h. so dass angrenzende Tintenpunkte nicht ineinander fließen können, und ein eher absorbierter Tintentropfen darf durchaus nicht "bluten", d.h. benachbarte oder später angebrachte Punkte überlappen,
• – durchsichtige Tintenstrahl-Aufzeichnungselemente müssen einerseits einen niedrigen Trübungswert und andererseits hervorragende Durchlässigkeitseigenschaften aufweisen,
• – das gedruckte Bild muss unter strengen Bedingungen von Temperatur und Feuchtigkeit mit einer guten Wasserbeständigkeit, Lichtbeständigkeit und Dauerhaftigkeit aufwarten,
• – das Tintenstrahl-Aufzeichnungselement darf sowohl vor als nach dem Drucken kein Kräuseln aufweisen und nicht klebrig sein,
• – das Tintenstrahl-Aufzeichnungselement muss zügig durch verschiedene Typen von Druckern laufen können.

As is known, various stringent requirements are imposed on the printing ink-receiving layers used in ink-jet recording elements

• The ink receiving layer should have a high ink absorbing capacity so that the dots will not flow out and will not propagate more than necessary to obtain a high optical density,
• The ink receiving layer should have a high ink absorbing speed (short ink drying time) so that the ink droplets will not leak if smeared immediately after spraying,
• - The ink dots applied to the printing ink layer should have a substantially round shape and be just on the circumference. The point diameter must be constantly and accurately controlled
• - the ink-receiving layer must be moistened quickly to avoid "puddling", ie, adjacent ink dots can not flow into each other, and a more-absorbed ink drop must not "bleed", ie adjacent or later attached dots overlap,
• Transparent ink jet recording elements must have a low haze value on the one hand and excellent permeability properties on the other hand;
• The printed image must have good water resistance, lightfastness and durability under severe conditions of temperature and humidity,
• The ink-jet recording element must not be curled before and after printing and should not be sticky,
• - The inkjet recording element must be able to run quickly through different types of printers.

Often have to compromises are made in achieving all of these characteristics. It is difficult, at the same time, to live up to all the above conditions to become.

The presence of absorptive pigments such as silica, kaolin, talc, alumina, boehmite, etc. in the ink receiving layer is known to cause an improvement in absorbency, color density and drying time. This effect is described in many patent applications for many different binder-based systems. From US-P 3,357,846 pigments such as kaolin, talc, barite and TiO ₂ in starch and PVA are known. U.S. Patent 3,889,270 describes the use of silica in gelatin, PVA and cellulose. Pigments and particles are also in patent applications such as in DE 2,925,769 , GB 2 050 866, US-P 4 474 850, US-P 4 547 405, US-P 4 578 285, WO 88 06532, US-P 4 849 286, EP 339 604 . EP 400 681 . EP 407 881 . EP 411 638 and U.S. Pat. No. 5,045,864 (non-exhaustive list).

These particulate Fabrics are available in various types of binders, of which the most common Types are gelatin, polyvinyl alcohol and polyvinylpyrrolidone, and dispersed in various types of cellulose derivatives. These usual Binders have been mentioned in numerous patents.

in the Framework of permanent Increase in printing speeds represents the subject of a fast Ink drop absorption is an extremely important Factor. A first drop must be in the inside of the receiving layer be absorbed into it, before a second drop to the same pixel arrives. To improve this property so are pigments with better absorption capacity indispensable.

The The present invention extends knowledge of ink absorbent Pigments in ink jet recording media.

TASKS OF PRESENT INVENTION

task The present invention is an ink jet recording element with high ink absorbency provide.

A Another object of the present invention is to provide an ink jet recording element to provide with very fast drying properties.

SHORT PRESENTATION THE PRESENT INVENTION

The above-mentioned objects are achieved by an ink-jet recording element containing a support and an ink-receiving layer containing a binder and a Ca ₃ (PO ₄ ) ₂ pigment, characterized in that the Ca ₃ (PO ₄ ) ₂ pigment consists predominantly of a Whitlockite crystal structure exists.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The essential feature of the present invention is that the pigment incorporated in the ink-receiving layer is calcium phosphate (Ca ₃ (PO ₄ ) ₂ ), which consists predominantly of the so-called whitlockite crystal structure and also as β-calcium triphosphate (β-CTP) is a rhombohedral crystal structure. By "predominantly" it is understood that most of the calcium phosphate present has this crystal structure. However, the ink-receiving layer may contain small amounts of other crystal structures, which may also differ stoichiometrically from Ca ₃ (PO ₄ ) ₂ , such as apatite, hydroxyapatite, monetite, etc. The type of crystal structure (s) contained can be checked by X-ray diffraction (XRD). The preparation of calcium phosphate of the whitlockite structure is described, inter alia, in US Pat. No. 5,939,039. Scientific publications on calcium phosphate and derivatives of the whitlockite type are disclosed, inter alia, by Lazoryak et al., "Triple phosphates of calcium, sodium, and trivalent elements with whitlockite". like structure ", Mater. Res. Bull. (1996), 31 (2), 207-16, L. Keller, "X-ray power diffraction patterns of calcium phosphates by the Rietveld method.", J. Biomed. Mater. Res., (1995), 29 (11), 1403-13, and Yanov et al., "A whitlockite calcium copper phosphate", Mater. Res. Bull. (1994), 29 (12), 1307-14.

calcium phosphate of the whitlockite crystal type are suitable for any orthopedic or Dental applications in which calcium phosphate is known to be used It is oncological, such as repairing bone filling defects, filling Error, the filling tooth extraction sites and applications for drug delivery. For example, see Jarcho et al., Synthesis and fabrication of β-tricalcium phosphate (whilockite) ceramics for potential prosthetic applications ", J. Mater. Sci. (1979), 14 (1) 142-50.

our But it is the first time that knowledge of the use of calcium phosphate of the whitlockite type as a pigment in an ink-jet-receiving layer is disclosed. Due to the presence of the compound, the Receiving layer has a high porosity and thereby becomes a noticeable improvement in the speed of recording ink drops achieved.

The Preferably, calcium phosphate of the whitlockite type is the only one Pigment of the ink-receiving layer. It can, however, with certain other commonly known pigments such as silica, talc, clay, kaolin, Diatomaceous earth, calcium carbonate, magnesium carbonate, aluminum hydroxide, Alumina, titania, zinc oxide, barium sulfate, calcium sulfate, Zinc sulfide, satin white, boehmite and pseudo-boehmite, or with organic particles such as polystyrene, polymethyl methacrylate, Silicones, urea-formaldehyde condensation polymers, polyesters and polyamides are combined.

When Binders are variously known to those skilled in the art Compounds in question, i.a. Hydroxyethyl cellulose, hydroxypropyl cellulose, Hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, hydroxybutylmethylcellulose, Methylcellulose, sodium carboxymethylcellulose, sodium carboxymethylhydroxyethylcellulose, water-soluble Ethyl hydroxyethyl cellulose, cellulose sulfate, polyvinyl alcohol, vinyl alcohol copolymers, Polyvinylacetal, polyvinylacetate, polyvinylpyrrolidone, polyacrylamide, Acrylamide / acrylic acid copolymer, Styrene / acrylic acid copolymer, Ethylene / vinyl acetate copolymer, vinyl methyl ether / maleic acid copolymer, Poly (2-acrylamido-2-methylpropanesulfonic acid), poly (diethylenetriamine-co-adipic acid), polyvinylpyridine, polyvinylimidazole, quaternized polyimidazoline, modified polyethyleneiminepichlorohydrin, ethoxylated polyethyleneimine, poly (N, N-dimethyl-3,5-dimethylene piperidinium chloride), Polyethylene oxide, polyurethane, melamine resins, gelatin, carrageenan, Dextran, gum arabic, casein, pectin, albumin, starch, collagen derivatives, collodion and agar-agar.

One preferred binder for The practice of the present invention is polyvinyl alcohol (PVA).

The total dry weight of the receiving layer is preferably between 10 and 40 g / m ² .

Besides the essential ingredients described above, a cationic substance acting as a mordant may be embedded in the ink-receiving layer. By using such substances, the layer is better able to fix and hold the dye of the ink drops. A special suitable compound is a poly (diallyldimethylammonium chloride) or abbreviated to a poly (dadmac). These compounds are available from several companies including Aldrich, Calgon, Clariant, BASF, EKA Chemicals and Nippon Goshei. A preferred type is GOHSEFIMER K210, trademark of Nippon Goshei Co.

Other useful cationic compounds include dadmac copolymers such as copolymers with acrylamide, dimethylamine-epichlorohydrin copolymers, eg POLYFIX 700, trademark of Showa High Polymer Co., other useful polyfix classes such as POLYFIX 601, POLYFIX 301, POLYFIX 301A, POLYFIX 250WS and POLYFIX 3000 , NEOFIX E-117, trademark of Nicca Chemical Co. for a polyoxyalkylene polyamine dicyandiamine, REDIFLOC 4150, trademark of EKA Chemicals for a polyamine, polymers modified with MADAME (methacrylate dimethylamine ethyl = dimethylamine ethyl methacrylate) or MADQUAT (methacryloxyethyl trimethyl ammonium chloride), eg ROHAGIT KL280, ROHAGIT 210, ROHAGIT SL144, PLEX 4739L and PLEX 3073 from Rohm, DIAFLOC KP155 and other DIAFLOC products from Diafloc Co., BMB 1305 and other BMB products from EKA Chemicals, cationic epichlorohydrin adducts such as POLYCUP 171 and POLYCUP 172, trademarks of Hercules Co., CYPRO products, eg CYPRO 514/515/516 and SUPERFLOC 507/521/567 from Cytec Industries, cationis Cellulose derivatives such as CELQUAT L-200, H-100, SC-240C, SC-230M, trademarks of Starch & Chemical Co., and QUATRISOFT LM200, the UCARE polymers JR125, JR400, LR400, JR30M and LR30M, and the UCARE Polymer LK, PALSET JK-512, PALSET JK512L, PALSET JK-182, PALSET JK-220, WSC-173, WSC-173L, PALSET JK-320, PALSET JK-320L and PALSET JK-350, all fixatives from Chukyo Europe Polyethyleneimine and copolymers, eg, LUPASOL, trademark of BASF AG, triethanolamine tartan chelate, eg TYZOR, trademark of Du Pont Co., copolymers of vinylpyrrolidone such as VIVIPRINT 111, trademark of ISP, methacrylamidepropyldimethylamine copolymer with dimethylamine ethylmethacrylate such as COPOLYMER 845 and COPOLYMER 937, trademark from ISP, with vinylimidazole, eg LUVIQUAT CARE, LUVITEC 73W, LUVITEC VPI55 K18P, LUVITEC VP155 K72W, LUVIQUAT FC905, LUVIQUAT FC550, LUVIQUAT HM522 and SOKALAN HP56, all trademarks of BASF AG, polyamidoamines, eg RETAMINOL and NADAVIN, trademarks of Bayer AG , and phosphonium like the ones in EP 609 930 . described

To other cationic compounds include gelatin when the pH the layer is below the isoelectric point of the gelatin, cationic alumina, boehmite and poly (aluminum hydroxychloride) such as SYLOJET A200, trademark by Grace Co. Other cationic polymers are polyvinylamines, e.g. PVAM-0595B from Esprit Co., cationic modified acrylic resins, e.g. ACRIT RKW319SX, trademark of Tasei Chemical Industries, and RD134 from Goo Chemical.

In an alternative embodiment, the cationic substance is incorporated not in the ink-receiving layer itself, but in a separate thin cover layer. In this case, the application of this layer is carried out from an aqueous medium. The dry layer weight is preferably between 0.5 and 5 g / m ² . The cationic mordant may also be distributed between the ink-receiving bulk layer and the additional thin topcoat. Depending on the surface properties of the substrate, an additional adhesive layer may be interposed between the support and the ink-receiving layer (underlying layer). The application of this layer is carried out from an aqueous medium containing any of the numerous known adhesive polymers. Preferred adhesive polymers include a styrene-butadiene latex, an acrylate latex such as ethyl acrylate-hydroxyethyl methacrylate, poly (ethylene vinyl acetate), polyvinyl esters, copolyesters, and polyurethanes.

The Dry layer weight of this possibly underlying layer is preferably between 0.5 and 10 g / m2.

The Ink-receiving layer, the possible cover layer and the eventual underlying layer can also commonly known conventional Ingredients such as surfactants used as pouring additives, hardeners, plasticizers, whiteners and matting agents.

The ink receiving layer of the present invention may contain any of the cationic, anionic, amphoteric and nonionic surfactants as described in JP-A 62-280068 (1987). Examples of surfactants are N-alkylamino acid salts, alkylether carboxylic acid salts, acylated peptides, alkylsulfonic acid salts, alkylbenzene and alkylnaphthalene sulfonic acid salts, sulfosuccinic acid salts, α-olefinsulfonic, N-acylsulfonic acid salts, sulfonated oils, alkylsulfonic acid salts, Alkylethersulfonsäuresalze, Alkylallylethersulfonsäuresalze, Alkylamidsulfonsäuresalze, alkylphosphoric acid salts, Alkyletherphosphorsäuresalze, Alkylallyletherphosphorsäuresalze, alkyl and Alkylallyl polyoxyethylene ethers, alkylallyl-formaldehyde-fused acid salts, alkyl allyl ether sulfonic acid salts, alkyl amide sulfonic acid salts, alkyl phosphoric acid salts, alkyl ether phosphoric acid salts, alkyl allyl phosphoric acid salts, alkyl and alkyl allyl polyoxyethylene ethers, with alkyl allyl formaldehyde hydrogenated polyoxyethylene ethers, block polymers with polyoxypropylene, polyoxyethylene polyoxypropyl alkyl ethers, polyoxyethylene ethers of glycol esters, polyoxyethylene ethers of sorbitan esters, polyoxyethylene ethers of sorbitol esters, aliphatic acidic polyethylene glycol esters, glycerol esters, sorbitan esters, propylene glycol esters, sugar esters, fluoro-C ₂ -C ₁₀ -alkylcarboxylic acids, disodium N-perfluorooctanesulfonylglutamate, Sodium 3- (fluoroC ₆ -C ₁₁ alkyloxy) -1-C ₃ -C ₄ alkylsulfonates, sodium 3- (ω-fluoroC ₆ -C ₈ alkanoyl-N-ethylamine) -1- propanesulfonates, N- [3- (perfluorooctanesulfonamide) -propyl] -N, N-dimethyl-N-carboxymethyleneammammonium betaine, fluoro-C ₁₁ -C ₂₀ -alkylcarboxylic acids, perfluoro-C ₇ -C ₁₃ -alkylcarboxylic acids, perfluorooctanesulfonic acid-diethanolamide, lithium , K and Na perfluoro C ₄ -C ₁₂ alkyl sulfonates, N-propyl N- (2-hydroxyethyl) perfluorooctanesulfonamide, perfluoro C ₆ -C ₁₀ alkylsulfonamidopropylsulfonylglycinates, bis (N-perfluorooctylsulfonyl-N-ethanolaminoethyl ) phosphonate, monoperfluoro-C ₆ -C _{1 6-} Alkylethylphosphonate and Perfluoralkylbetain.

To usable cationic surfactants include N-alkyldimethylammonium chloride, Palmityltrimethylammonium chloride, dodecyldimethylamine, tetradecyldimethylamine, an ethoxylated alkylguanidineamine complex, oleamine hydroxypropyl bistrimonium chloride, Oleylimidazoline, stearylimidazoline, cocamine acetate, palmitamine, dihydroxyethylcocamine, Cocotrimonium chloride, alkyl polyglycol ether ammonium sulfate, ethoxylated Oleamine, laurylpyridinium chloride, N-oleyl-1,3-diaminopropane, stearamidopropyldimethylamine lactate, Coconut fatty acid amide, oleylhydroxyethylimidazoline, Isostearylethylimidonium ethosulfate, lauramidopropyl PEG-dimonium chloride phosphate, Palmityltrimethylammonium chloride and cetyltrimethylammonium bromide.

Particularly useful is for example in US-P fluorocarbon surfactant described 4,781,985 of the formula F (CF _{2) 4-9} CH ₂ CH ₂ SCH ₂ CH ₂ N ⁺ R ₃ X ^-, in which R is a hydrogen atom or an alkyl group means, and the method described in US-P 5,084,340 fluorocarbon surfactant of the formula CF ₃ (CF _{2) m} CH ₂ CH ₂ O (CH ₂ CH ₂ O) _n R, in which m = 2 to 10, n = 1 to 18 and R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. These surfactants are available from DuPont and 3M. The ratio of the surfactant component in the printing ink-receiving layer is generally between 0.1 and 2 wt .-%, preferably between 0.4 and 1.5 wt .-% and is very particularly preferably 0.75 wt .-%, based on the total dry weight of the layer.

The Inventive ink receiving layer can be networked to desired Properties like water resistance and avoiding sticking together. By networking the layer is further rendered abrasion resistant and protected from while handling fingerprints to remain on the element. There are a variety of known, also known as curing crosslinking agents, which crosslink the film-forming materials. Hardeners can be used individually or in combination and used in free or blocked form. There is a Wide range of inventively usable Hardeners. These include Formaldehyde and free dialdehydes such as succinaldehyde and glutaraldehyde, blocked dialdehydes, active esters, sulfonate esters, active halogen compounds, Isocyanate or blocked isocyanates, polyfunctional isocyanates, Melamine derivatives, s-triazines and diazines, epoxides, active olefins with two or more active bonds, carbodiimides, substituted in the 3-position Isoxazolium salts, esters of 2-alkoxy-N-carboxydihydroquinoline, N-carbamoylpyridinium salts, Harder with a mixed function, such as halogen-substituted aldehyde acids (e.g., mucochloro and mucobromic acids), onium-substituted acroleins and vinylsulfones and polymeric hardeners such as dialdehyde and a copolymer of acrolein and methacrylic acid and polymers having a Oxazoline function, e.g. the EPOCROS WS-500 series and the EPOCROS K-1000 series.

In Boric acid is a preferred crosslinking agent in the practice of the present invention.

The Inventive ink receiving layer may also contain a plasticizer such as ethylene glycol, diethylene glycol, Propylene glycol, polyethylene glycol, glycerol monomethyl ether, glycerol monochlorohydrin, Ethylene carbonate, propylene carbonate, tetrachlorophthalic anhydride, tetrabromophthalicanhydride, Urea phosphate, triphenyl phosphate, glycerol monostearate, propylene glycol monostearate, Tetramethylene sulfone, N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone contain.

The Inventive ink receiving layer may also contain ingredients that resist light of the printed image, such as antioxidants, UV absorbers, Peroxide, extinguisher for singlet oxygen such as HALS compounds (Hindered Amine Light Stabilizers) etc.

The ink-receiving layer and any additional layers may be applied to the support by any conventional coating technique such as dip coating, curtain coating, extrusion coating, spin coating, cascade coating and curtain coating. As the support of this invention, a paper support and polymeric support well known in photographic technology may be used. As paper carriers are plain paper, cast-coated paper, polyethy lenbeschichtetes paper and polypropylene coated paper. Polymeric supports include cellulose acetate propionate or cellulose acetate butyrate, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate, polyamides, polycarbonates, polyimides, polyolefins, poly (vinyl acetals), polyethers and polysulfonamides. Other examples of high-quality polymeric supports which can be used according to the invention include opaque white polyesters and extrusion blends of polyethylene terephthalate and polypropylene. Polyester film supports, and especially polyethylene terephthalate supports, are preferred for their excellent dimensional stability properties.

To typical straps for outdoor use counting PET, wet strength paper, PVC, PVC with an adhesive backing, TYVEK polyethylene paper, trademark of Du Pont Co., TESLIN porous polyethylene paper, Trademark of International Paper CO., Kanevas, Polypropylene and polycarbonate.

The The present invention will now be apparent from the following examples illustrated but not limited thereto.

EXAMPLES

Example 1 (comparative Example)

Preparation of the Ca ₃ (PO ₄ ) ₂ dispersion

A Ca ₃ (PO ₄ ) ₂ powder sold and manufactured by Merck is first ground with zirconium silicate beads with a diameter of 0.6 mm in a sand mill (Spangenberg). After grinding for 6 hours, Ca ₃ (PO ₄ ) ₂ pigments having a particle size between 1 and 2 μm are obtained. Following the grinding process, the beads are separated by filtration and washing with water. The pigment content of the sludge is 12% by weight. The pigment is a heterogeneous mixture of different crystal structures, as shown by an XRD diagram (X-ray diffraction diagram).

Applying the Casting Solutions

To prepare a coating liquid to form an ink receiving layer, 5 parts by weight of a 10% aqueous solution of polyvinyl alcohol (POVAL 117, trademark of KK Kuraray) is added to 94.5 parts by weight of the prepared Ca ₃ (PO ₄ ) ₂ dispersion. Finally, 0.5 part by weight of a boric acid solution is added as crosslinking agent.

The thus obtained coating liquid has a total solids content of 11.2% by weight.

coating the pattern

The casting solution is spread on a subbed PET sheet (100 μm thick) to give an ink receiving layer having a dry weight of 28 g / m ² and dried at 40 ° C. The pore volume of the layer determined by the nitrogen gas adsorption method is only 0.07 ml / g.

On the coated patterns are printed using an EPSON STYLUS COLOR 460 Printer (trademark of Seiko Epson Corp.) Swatches with primary colors and secondary colors printed. On the basis of these color fields, the drying time, determines the color density and the bleeding of the colors. The test results are listed in Table 1.

Example 2 (comparative Example)

One Ink jet recording medium is analogous to the method in Example 1 produced, but with the following difference. In the preparation of the coating liquid for the Ink-receiving layer is used instead of the polyvinyl alcohol a cation - one modified polyvinyl alcohol (GOHSEFIMER K210, trademark of Nippon Gohsei). The test results are listed in Table 1.

Example 3 Example According to the Invention

An ink jet recording medium is prepared analogously to the method in Example 1, but with the following difference. In the preparation of the dispersion for the ink receiving layer, instead of the Ca ₃ (PO ₄ ) ₂ powder, a porous type (marketed by Orthovita Inc.) is used with one by XRD proven whitlockite crystal structure. The pore volume of the layer determined by the nitrogen gas adsorption method is 0.39 ml / g, which is a much higher value than in the comparative example. Further test results are listed in Table 1.

Example 4 (Inventive Example)

An ink jet recording medium is prepared analogously to the method in Example 2, but with the following difference. In preparing the dispersion for the ink receiving layer, instead of the Ca ₃ (PO ₄ ) ₂ powder, a porous type (sold by Orthovita Inc.) having an XRD-proved whitlockite crystal structure is used. The test results are listed in Table 1.

Evaluation of the patterns

Table 1: Test results

From the results, it can be seen that the porous Ca ₃ (PO ₄ ) ₂ powder provides a substantial improvement in drying time and reduction in color bleeding.

Claims (6)

An ink-jet recording element containing a support and an ink-receiving layer containing a binder and a Ca ₃ (PO ₄ ) ₂ pigment, characterized in that the Ca ₃ (PO ₄ ) ₂ pigment consists predominantly of a whitlockite crystal structure. An ink jet recording element according to claim 1, characterized in that the binder is polyvinyl alcohol. An ink jet recording element according to claim 1 or 2, characterized in that the ink-receiving layer is further contains a crosslinking agent. An ink jet recording element according to claim 3, characterized in that the crosslinking agent is boric acid. Ink jet recording element according to one of claims 1 to 4, characterized in that the ink-receiving layer further contains a cationic mordant. An ink jet recording element according to claim 5, characterized in that the cationic mordant is poly (diallyldimethylammonium chloride) is.