Recording sheets for ink jet printing

1. Recording sheet for ink jet printing having coated onto a support at least one ink-receiving layer consisting of binders and at least one nanocrystalline, nanoporous inorganic compound prepared in the absence of acids, wherein the recording sheet contains the polynuclear aluminum hydroxo complex Al 30 with 30 aluminum atoms which was combined with an aqueous dispersion of SiO 2 and heated for at least 60 minutes at a temperature of 60° C. to produce the coated recording sheet having improved storage stability of the printed images thereon when in contact with ambient air.

2. The recording sheet according to claim 1 , wherein said polynuclear aluminum hydroxo complex is present from 0.01 to 0.8 mole percent relative to the quantity of the nanocrystalline, nanoporous inorganic compounds.

3. The recording sheet according to claim 1 , wherein said polynuclear aluminum hydroxo complex is present from 0.1 to 0.6 mole percent relative to the quantity of the nanocrystalline, nanoporous inorganic compounds.

4. The recording sheet according to claim 1 , wherein said polynuclear aluminum hydroxo complex is added to an aqueous dispersions of the nanocrystalline, nanoporous inorganic compounds as an aqueous solution.

5. The recording sheet according to claim 1 , wherein said polynuclear aluminum hydroxo complex is coated over said ink-receiving layer.

6. The recording sheet according to claim 1 , wherein said nanocrystalline, nanoporous inorganic compound is silicium dioxide.

7. The recording sheet according to claim 6 , wherein said silicium dioxide is fumed silica prepared in a gas phase reaction.

8. The recording sheet according to claim 1 , wherein said nanocrystalline, nanoporous inorganic compound is aluminum oxide or aluminum oxide/hydroxide 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 0.2 to 2.5 mole percent relative to Al 2 O 3 .

9. The recording sheet according to claim 1 , wherein said support is selected from the group consisting of coated paper, uncoated paper, transparent polyester, opaque polyester or fibrous textile materials.

10. The recording sheet according to claim 1 , further containing organic sulfur compounds.

11. The recording sheet according to claim 1 , wherein said binder is a water-soluble polymer.

12. The recording sheet according to claim 1 , wherein said binder is selected from the group consisting of albumin, gelatin, casein, starch, gum arabicum, sodium alginate, potassium alginate, hydroxyethyl cellulose, carboxymethyl cellulose, α-cyclodextrine, β-cyclodextrine, γ-cyclodextrine, acid pigskin gelatin, limed bone gelatin, acid hydrolyzed gelatin, base hydrolyzed gelatin, phthalaoylated gelatin, acetylated gelatin, carbamoylated gelatin, gelatin derivatized with the anhydride of trimellitic acid, polyvinyl alcohol, polyvinyl pyrrolidone, completely or partially saponified products of copolymers of vinyl acetate; maleic acid, (meth)acrylic acid or crotonic acid; vinylsulfonic acid, styrene sulfonic acid; homopolymers or copolymers of vinyl monomers of (meth)acrylamide; homopolymers or copolymers of other monomers with ethylene oxide; polyurethanes; polyacrylamides; water-soluble nylon type polymers; polyesters; polyvinyl lactams; acrylamide polymers; substituted polyvinyl alcohol; polyvinyl acetals; polymers of alkyl and sulfoalkyl acrylates and methacrylates; hydrolyzed polyvinyl acetates; polyamides; polyvinyl pyridines; polyacrylic acid; copolymers with maleic anhydride; polyalkylene oxides; methacrylamide copolymers and maleic acid copolymers.

13. The recording sheet according to claim 12 , wherein said ink-receiving layer comprises a mixture of at least two binders.

14. The recording sheet according to claim 1 , further comprising a cross-linking agent.

15. The recording sheet according to claim 1 , wherein said cross-linking agent is selected from the group consisting of aldehydes, N-methylol compounds, dioxanes, reactive vinyl compounds, reactive halogen compounds, epoxides; aziridines, carbamoyl pyridinium compounds, chromium alum, aluminum alum and boric acid.

16. The recording sheet according to claim 15 , wherein said cross-linking agent is selected from the group consisting of formaldehyde, glyoxal, mglutaraldehyde, dimethylol urea, methylol dimethylhydantoin, 2,3-dihydroxydioxane, 1,3,5-trisacroyl hexahydro-s-triazine, bis-(vinylsulfonyl)methyl ether and 2,4-dichloro-6-hydroxy-s-triazine.

17. The recording sheet according to claim 1 , wherein the recording sheet contains a mixture of at least two nanocrystalline, nanoporous inorganic compounds.

18. The recording sheet according to claim 1 , further comprising additional ink-receiving layers.

19. Pigment containing compositions for the preparation of ink-receiving layers for recording sheets for ink jet printing according to claim 1 .

20. A method of preparing a recording sheet for ink jet printing with improved storage stability comprising the steps of:

adding an aqueous dispersion of SiO 2 to an aqueous solution of a nanocrystalline, nanoporous inorganic compound comprising a polynuclear aluminum hydroxo complex Al 30 with 30 aluminum atoms, at a temperature of 20° C. to create a mixture;

dispersing said mixture to form a dispersion;

heating said dispersion for at least sixty minutes at a temperature of 60° C. to produce an aqueous dispersion of positively charged SiO 2 ;

combining said dispersion with an aqueous solution of polyvinyl alcohol and an aqueous solution of boric acid to produce an ink receiving coating solution;

coating said solution on a support; and

drying said solution forming the ink receiving layer to produce a coated recording sheet for ink jet printing having improved storage stability of the printed images thereon when in contact with ambient air.