Primary particles coated with a chromophoric component

Abstract

The invention relates to suspension of primary particles of oxide-ceramic material, wherein the primary particles have an average particle size in the range from 10 to 1000 nm and are coated with a chromophoric component, a process for their preparation and their use in particular in the preparation of ceramic mouldings and dental restorations. The invention further relates to a process for the preparation of ceramic mouldings.

1 . Suspension based on oxide-ceramic material, which comprises 10-95 wt.-% primary particles of oxide-ceramic material, wherein the primary particles have an average particle size in the range from 10 to 1000 nm and are coated with a chromophoric component, 5-90 wt.-% organic component, in each case relative to the overall mass of the suspension. 
     
     
         2 . The suspension according to  claim 1 , wherein the oxide-ceramic material comprises ZrO 2 . 
     
     
         3 . The suspension according to  claim 1 , wherein the oxide-ceramic material comprises ZrO 2  stabilized with Y 2 O 3 . 
     
     
         4 . The suspension according to  claim 1 , wherein the chromophoric component comprises a transition metal compound. 
     
     
         5 . The suspension according to  claim 1 , wherein the chromophoric component comprises an acetyl acetonate or a carboxylic acid salt of the elements iron, cerium, praseodymium, terbium, lanthanum, tungsten, osmium, or manganese. 
     
     
         6 . The suspension according to  claim 1 , wherein the primary particles contain 0.000001 to 0.4 wt.-% chromophoric component, relative to the overall mass of the primary particles. 
     
     
         7 . The suspension according to  claim 1 , wherein the primary particles have an average primary particle size in the range from 10 to 500 nm. 
     
     
         8 . Suspension according to  claim 1 , which comprises
 (A) 10 - 95 wt.-% primary particles,   (B) 3-85 wt.-% polyreactive binder and   (C) 1-80 wt.-% organic solvent and   (D) 1 to 30 wt.-% further additives,   in each case relative to the overall mass of the suspension.   
     
     
         9 . Suspension according to  claim 1 , which has a viscosity in the range from 200 to 20,000 mPa·s. 
     
     
         10 . The suspension according to  claim 5 , wherein the chromophoric component comprises iron (III) acetate or iron (III) acetylacetonate, manganese (III) acetate or manganese (III) acetylacetonate, praseodymium (III) acetate or praseodymium (III) acetylacetonate or terbium (III) acetate or terbium (III) acetylacetonate. 
     
     
         11 . The suspension according to  claim 7 , wherein the average primary particle size is in the range from 10 to 200 nm 
     
     
         12 . The suspension according to  claim 9 , which has a viscosity in the range from 200 mPa·s to 2,000 Pa·s. 
     
     
         13 . Use of a suspension according to  claim 1  for the preparation of ceramic mouldings. 
     
     
         14 . Use according to  claim 13 , wherein the ceramic mouldings is a dental restoration, an inlay, onlay, veneer, a crown, bridge or a framework. 
     
     
         15 . Process for the preparation of a ceramic mouldings comprising
 (a) preparing a green body by curing a suspension according to  claim 1  by local introduction of radiation energy with formation of the geometric shape of the green body,   (b) subjecting the green body to a heat treatment to remove the binder, in order to obtain a white body, and   (c) sintering the white body.