Hardened shaped article

Abstract

A shaped article including inorganic fibers including SiO 2 and an alkaline earth metal, wherein the shaped article is treated with a hardening agent.

1 . A shaped article comprising 20 wt % to 99 wt % of bio-soluble inorganic fibers comprising SiO 2  and an alkaline earth metal, wherein the shaped article is impregnated from the surface thereof with a hardening agent which is colloidal silica and the surface is hardened. 
     
     
         2 . (canceled) 
     
     
         3 . The shaped article according to  claim 1 , wherein the shaped article is impregnated with a metal ion free-chelating agent in addition to the hardening agent. 
     
     
         4 . The shaped article according to  claim 3 , wherein the chelating agent is EDTA.H.3(NH 4 ) or EDTA.H.2(NH 4 ). 
     
     
         5 . The shaped article according to  claim 1 , wherein the shaped article is impregnated with an acid together with the hardening agent. 
     
     
         6 . The shaped article according to  claim 5 , wherein the acid is a hydroxyl acid. 
     
     
         7 . The shaped article according to  claim 5 , wherein the acid is at least one selected from the group consisting of citric acid, malic acid, tartaric acid and salicylic acid. 
     
     
         8 . The shaped article according to  claim 1 , wherein the hardening agent is an acidic colloidal silica or a cationic colloidal silica. 
     
     
         9 . The shaped article according to  claim 8 , wherein a pH value of the acidic colloidal silica is about 2 to about 5. 
     
     
         10 . (canceled) 
     
     
         11 . (canceled) 
     
     
         12 . The shaped article according to  claim 1 , wherein the inorganic fibers have the following composition.
 Total of SiO 2 , ZrO 2 , AI 2 O 3  and TiO 2 : about 50 wt % to about 82 wt %   Total of alkali metal oxides and alkaline earth metal oxides: about 18 wt % to about 50 wt %   
     
     
         13 . The shaped article according to  claim 1 , wherein the inorganic fibers have the following composition.
 SiO 2 : about 50 wt % to about 82 wt %   Total of CaO and MgO: about 10 wt % to about 43 wt %   
     
     
         14 . (canceled) 
     
     
         15 . (canceled) 
     
     
         16 . A method of hardening a shaped article comprising impregnating a shaped article comprising 20 wt % to 99 wt % of bio-soluble inorganic fibers comprising SiO 2  and an alkaline earth metal with a hardening treatment solution comprising colloidal silica, and drying the shaped article. 
     
     
         17 . The shaped article according to  claim 1 , wherein the inorganic fibers are Mg filicate fibers having the following composition or Ca silicate fibers having the following composition.
 [Mg silicate fiber]
 SiO 2 : 66 wt % to 82 wt % 
 CaO: 1 wt % to 9 wt % 
 MgO: 10 wt % to 30 wt % 
 AI2O3: 3 wt % or less 
 Other oxides: less than 2 wt % 
   [Ca silicate fiber]
 SiO 2 : 66 wt % to 82 wt % 
 CaO: 10 wt % to 34 wt % 
 MgO: 3 wt % or less 
 AI 2 O 3 : 5 wt % or less 
 Other oxides: less than 2 wt % 
   
     
     
         18 . The method according to  claim 16 , wherein the hardening treatment solution further comprises a metal ion free-chelating agent or an acid. 
     
     
         19 . A shaped article hardened by the method according to  claim 16  or  18 .