Recording sheet for ink jet printing

Abstract

A method for the preparation of silicium dioxide dispersions is provided, wherein the surface of the silicium dioxide is modified by a treatment with the reaction products, formed in a separate reaction step, of at least one compound of trivalent aluminum or of tetravalent zirconium or a mixture thereof with at least one aminoorganosilane; and the invention also relates to recording sheets for ink jet printing having such a dispersion incorporated in an ink-receiving layer.

1 . Method of preparation of dispersions of surface modified silicium dioxide, characterised by the fact that the surface of the silicium dioxide wherein the surface of the silicium dioxide is modified by a treatment with the reaction products of at least one compound of trivalent aluminum and/or tetravalent zirconium with at least one aminoorganosilane and
 a layer of 1 cm thickness of an aqueous solution, prepared at room temperature, of 0.01 moles of aluminum chlorohydrate, 0.02/k moles of aminoorganosilane or a mixture of aminoorganosilanes, 0.01 moles of hydrochloric acid and 0.02 moles of glyoxal, having a final weight of 200 g, and stored for 24 hours at room temperature, shows an absorption increase of less than 0.05 at a wavelength of 400 nm after storage, wherein k is the number of amino groups of the aminoorganosilane or a mean value of the numbers of amino groups of the individual aminoorganosilanes in the mixture of aminoorganosilanes   
     
     
         2 . Method of preparation of dispersions of surface modified silicium dioxide according to  claim 1 , wherein the compound of trivalent aluminum is selected from the group consisting of aluminum chloride, aluminum nitrate, aluminum acetate, aluminum formiate, aluminum lactate, aluminum chlorohydrate or mixtures of these compounds. 
     
     
         3 . Method of preparation of dispersions of surface modified silicium dioxide according to  claim 1 , wherein the compound of tetravalent zirconium is zirconyl chloride. 
     
     
         4 . Method of preparation of dispersions of surface modified silicium dioxide according to  claim 1 , wherein the aminoorganosilane is of formula (I) 
       
         
           
           
               
               
           
         
         wherein 
         R 1 , R 2 , R 3  independently represent hydrogen, hydroxyl, unsubstituted or substituted alkyl with 1 to 6 carbon atoms, unsubstituted or substituted aryl, unsubstituted or substituted alkoxyl with 1 to 6 carbon atoms or unsubstituted or substituted aryloxyl 
         and 
         R 4  represents an organic moiety substituted by at least one primary, secondary or tertiary amino group. 
       
     
     
         5 . Method of preparation of dispersions of surface modified silicium dioxide according to  claim 3 , wherein the substituents of R 1 , R 2  and R 3  are independently selected from the group consisting of thiol, sulfide and polyalkylene oxide. 
     
     
         6 . Method of preparation of dispersions of surface modified silicium dioxide according to  claim 1 , wherein the aminoorganosilane is selected from the group consisting of N-(n-butyl)-aminopropyltrimethoxysilane, N-(ethyl)-aminoisobutyltrimethoxysilane and N-(cyclohexyl)-aminomethyltriethoxysilane or mixtures thereof. 
     
     
         7 . Method of preparation of dispersions of surface modified silicium dioxide according to  claim 1 , wherein the amount of the compound of trivalent aluminum and/or tetravalent zirconium is from 0.1 to 20 percent by weight relative to the amount of silicium dioxide. 
     
     
         8 . Method of preparation of dispersions of surface modified silicium dioxide according to  claim 1 , wherein the silicium dioxide is fumed silicium dioxide. 
     
     
         9 . Method of preparation of dispersions of surface modified silicium dioxide according to  claim 8 , wherein the fumed silicium dioxide has a specific surface area between 20 m 2 /g and 400 m 2 /g. 
     
     
         10 . Method of preparation of dispersions of surface modified silicium dioxide according to  claim 9 , wherein a mixture of two or more different fumed silicium dioxides having different specific surface areas is used. 
     
     
         11 . Method of preparation of dispersions of surface modified silicium dioxide according to  claim 10 , wherein the surface modification of the different fumed silicium dioxides is done simultaneously in their mixture. 
     
     
         12 . Method of preparation of dispersions of surface modified silicium dioxide according to  claim 10 , wherein the surface modification of the different fumed silicium dioxides is done individually for each fumed silicium dioxide. 
     
     
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