Mineral fibers decomposable in a physiological medium

Abstract

The present invention relates to mineral fiber compositions useful for forming fibers which are readily degraded in a physiological medium such as that found within the human body. Advantageous compositions formed according to the present invention comprise the following components in the proportions by weight set forth below: ______________________________________ SiO 2 37 to 58 wt. %; Al 2 O 3 4 to 14 wt. %; CaO 7 to 40 wt. %; MgO 4 to 16 wt. %; P 2 O 5 1 to 10 wt. %; Fe 2 O 3 up to about to 15 wt. %: ______________________________________ wherein the amount of CaO+MgO+Fe 2 O 3 is greater than 25% and the total amount of Na 2 O+K 2 O is less than 7%. The total iron contained within the composition is expressed in the form of ferric oxide (Fe 2 O 3 ).

We claim: 
     
       1. A mineral fiber composition decomposable in a physiological medium, said composition consisting essentially of:   ______________________________________                                    
SiO.sub.2         37 to 58 wt. %;                                         
Al.sub.2 O.sub.3  4 to 11.5 .[.14.]. wt. %;                               
CaO               7 to 40 wt. %;                                          
MgO               4 to 16 wt. %;                                          
P.sub.2 O.sub.5   1 to 7 .[.10.]. wt. %;                                  
Fe.sub.2 O.sub.3  0.1 to 15 wt. %;                                        
Na.sub.2 O + K.sub.2 O                                                    
                  up to about 7 wt. %; and                                
Impurities        up to about 3 wt. %,                                    
______________________________________                                    
     wherein the amount of CaO+MgO+Fe 2  O 3  is greater than 25 wt. % of the composition.   
     
     
       2. The composition of claim 1, wherein the amount of SiO 2  +Al 2  O 3  is greater than about 50 wt % of said composition. 
     
     
       3. The composition of claim 1 wherein the amount of CaO+MgO less than about 40 wt % of said composition. 
     
     
       4. A mineral fiber composition decomposable in a physiological medium, said composition consisting essentially of:   ______________________________________                                    
SiO.sub.2         45 to 57 wt. %;                                         
Al.sub.2 O.sub.3  3 to 6 wt. %.                                           
CaO               20 to 30 wt. %                                          
MgO               6 to 16 wt. %;                                          
Fe.sub.2 O.sub.3  1 to 7 wt. %;                                           
P.sub.2 O.sub.5   0.1 to 4 wt. %;                                         
Na.sub.2 O + K.sub.2 O                                                    
                  0.1 to 5 wt. %;                                         
Impurities        up to about 3 wt. %                                     
______________________________________                                    
     wherein the amount of CaO+MgO+Fe 2  O 3  is greater than about 25 wt % of said composition.   
     
     
       5. A mineral fiber composition decomposable in a physiological medium, said composition consisting essentially of:   ______________________________________                                    
SiO.sub.2         40 to 50 wt. %;                                         
Al.sub.2 O.sub.3  7 to 11.5 .[.13.]. wt. %;                               
CaO               20 to 30 wt. %;                                         
MgO               6 to 16 wt. %;                                          
P.sub.2 O.sub.5   3 to 7 .[.9.]. wt. %;                                   
Fe.sub.2 O.sub.3  up to about 4 wt. %;                                    
Na.sub.2 O + K.sub.2 O                                                    
                  0.1 to 5 wt. %; and                                     
Impurities        up to about 3 wt. %;                                    
______________________________________                                    
     wherein the amount of CaO+MgO+Fe 2  O 3  is greater than 25 wt. % of the composition.   
     
     
       6. Mineral fibers comprising the mineral fiber compositions set forth in any one of claims 1 to 5. 
     
     
       7. An insulating material comprising the mineral fibers of claim 6. .Iadd. 
     
     
       8.  A mineral fiber composition decomposable in a physiological medium, said composition consisting essentially of: SiO 2  in an amount of about 45 to 57 wt. %   Al 2  O 3  in an amount of about 4 to 6 wt. %   CaO in an amount of about 7 to 40 wt. %   MgO in an amount of about 4 to 9.1 wt. %   P 2  O 5  in an amount of about 1 to 7 wt. %   Fe 2  O 3  in an amount of about 2.1 to 15 wt. %, and   Na 2  O+K 2  O in an amount of about 0.1 to 5 wt. %; wherein the composition contains impurity elements in an amount of less than about 3 wt. % and the amount of CaO+MgO+Fe 2  O 3  is greater than 25 wt. % of the composition.Iaddend.. .Iadd.   
     
     
       9.  A mineral fiber composition decomposable in a physiological medium, said composition consisting essentially of about 49.7 wt. % SiO 2 , about 2.1 wt. % Fe 2  O 3 , about 4.5 wt. % Al 2  O 3 , about 29.5 wt. % CaO, about 7.4 wt. % MgO, about 1.4 wt. % Na 2  O, about 1.3 wt. % K 2  O, about 3 wt. % P 2  O 5  and impurities in an amount of about 1.1 wt. %, wherein the weight ratio of P 2  O 5  to (Al 2  O 3  and Fe 2  O 3 ) is about 0.45..Iaddend.