Curable compositions

Abstract

Certain aluminum compounds, such as aluminum alkoxides, chelates and acylates, catalyst the reaction of .tbd.SiOH with ##STR1## to yield compositions containing ##STR2## linkages.

That which is claimed is: 
     
       1. A method of preparing compositions containing silicon-oxygen-carbon bonds comprising reacting under substantially anhydrous conditions A. an organosilicon compound containing at least one .tbd.SiOH group with   B. a compound containing at least one epoxy group, .Iadd.no hydroxyl groups and selected from the group consisting of aliphatic, cycloaliphatic and hetrocyclic epoxy reactants, silylated epoxides and polyglycidyl ethers of novalac condensation products, .Iaddend.said reaction being carried out in the presence of a catalytic amount of   C. an aluminum compound selected from the group consisting of a. Al(OR) 3  in which R is either a hydrogen atom or .Iadd.is .Iaddend.selected from the group consisting of alkyl radicals contaning from 1 to 20 inclusive carbon atoms or aryl and aryl-containing hydrocarbon radicals containing from 6 to 24 inclusive carbon atoms; ##STR34## in which R is as previously defined, R' is selected from the group consisting of the hydrogen atom, alkyl radicals containing from 1 to 30 inclusive carbon atoms and aryl or aryl-containing radicals of at least 6 carbon atoms, n having a value of from 0 to 2 and condensates of such compounds;   c. aluminum salts of the formula   H.sup.+ Al.sup.- (OR).sub.4     in which R is as previously defined;     d. aluminosiloxy compounds of the formula   ═Al.OSIR.sub.3.sup.2     in which R 2  is selected from the group consisting of --OR radicals in which R is as defined, ##STR35## radicals in which R' is as defined, monovalent hydrocarbon or halohydrocarbon radicals containing from 1 to 30 inclusive carbon atoms, and siloxane moieties of the formula ##STR36## in which R 3  is selected from the group consisting of OR radicals in which R is as defined, ##STR37## radicals in which R' is as defined and monovalent hydrocarbon or halohydrocarbon radicals containing from 1 to 30 inclusive carbon atoms, and a has a value of from 1 to 3; the remaining aluminum valences being satisfied by --OAl═, --OR ##STR38## or --OSIR 3   2  bonding, R, R' and R 2  being as previously defined; and     e. aluminum chelates formed by reacting compounds (a), (b) or (c) with sequestering agents in which the coordinating atoms are oxygen.     
     
     
       2. A method in accordance with claim 1 wherein (A) is a hydroxyl-functional organopolysiloxane. 
     
     
       3. A method in accordance with claim 2 wherein (A) is of the formula ##EQU3## in which R 4  is a monovalent hydrocarbon radical selected from the group consisting of alkyl radicals of from 1 to 6 inclusive carbon atoms and the phenyl radical; R 5  is an alkyl radical of from 1 to 6 inclusive carbon atoms; a is an integer having a value of 1 or 2; b having a value of 0 or 1, the sum of a+b being no more than 2; c is an integer having a value of 1 or 2, d is an integer having a value of from 1 to 3; e having a value of 0 to 2, the sum of d+e being no more than 3; x having a value of at least 1 and y having a value of 0 or more. 
     
     
       4. A method in accordance with claim 3 wherein the organopolysiloxane has from 1.0 to 1.7 R 4  substituents per silicon atom and contains at least 2 weight percent silanol groups. 
     
     
       5. A method in accordance with claim 2 wherein (B) is a polyepoxide. 
     
     
       6. A method in accordance with claim 5 wherein the polyepoxide (B) is a cycloaliphatic polyepoxide. .[.7. A method in accordance with claim 5 wherein the polyepoxide (B) is obtained by the reaction of polyhydric phenols with polyfunctional halohydrins..]. .[.8. A method in accordance with claim 7 wherein the polyepoxide (B) is obtained by the reaction of 
     
     
        polyhydric phenols with epichlorohydrin..]. 9. A method in accordance with claim 1 wherein the aluminum compound is of the formula 
     
     
       Al(OR) 3  10. A method in accordance with claim 1 wherein the aluminum compound is of the formula ##STR39## 
     
     
        11. A method in accordance with claim 1 wherein the aluminum compound is 
     
     
        an aluminum chelate. 12. A method in accordance with claim 1 wherein the aluminum compound is an aluminosiloxy compound of the formula 
     
     
       .tbd.AlOSiR 3   2  13. A method in accordance with claim 1 wherein the aluminum catalyst is present in an amount in the range of from 0.05 to 5 
     
     
        weight percent based on the total weight of (A)+(B). 14. A substantially anhydrous composition comprising A. an organosilicon compound containing at least one silicon-bonded hydroxyl group;   B. a compound containing at least one epoxy group.Iadd., no hydroxyl groups and selected from the group consisting of aliphatic, cycloaliphatic and hetrocyclic epoxy reactants, silylated epoxides and polyglycidyl ethers of novalac condensation products.Iaddend.;   C. a catalytic amount of an aluminum compound selected from the group consisting of a. Al(OR) 3  in which R is either a hydrogen atom or selected from the group consisting of alkyl radicals containing from 1 to 20 inclusive carbon atoms or aryl and aryl-containing hydrocarbon radicals containing from 6 to 24 inclusive carbon atoms; ##STR40## in which R is as previously defined, R' is selected from the group consisting of the hydrogen atom, alkyl radicals containing from 1 to 30 inclusive carbon atoms and aryl or aryl-containing radicals of at least 6 carbon atoms, n having a value of from 0 to 2 and condensates of such compounds;   c. aluminum salts of the formula   H.sup.+ Al.sup.- (OR).sub.4     in which R is as previously defined;     d. aluminosiloxy compounds of the formula   ═AlOSiR.sub.3.sup.2     in which R 2  is selected from the group consisting of --OR radicals in which R is as defined, ##STR41## radicals in which R' is as defined monovalent hydrocarbon or halohydrocarbon radicals containing from 1 to 30 inclusive carbon atoms, and siloxane moieties of the formula ##STR42## in which R 3  is selected from the group consisting of OR radicals in which R is as defined, ##STR43## radicals in which R' is as defined and monovalent hydrocarbon or halohydrocarbon radicals containing from 1 to 30 inclusive carbon atoms, and a has a value of from 1 to 3; the remaining aluminum valences being satisfied by --OAl═, --OR, ##STR44## or --OSiR 3   2  bonding, R,R' and R 2  being as previously defined; and     e. aluminum chelates formed by reacting compounds .[.(a), (b) or (c).]. .Iadd.(A), (B), or (C) .Iaddend.with sequestering agents in which the coordinating atom is oxygen, said organosilicon compond (A) being present in an amount sufficient to provide at least 0.1 .tbd.SiOH group per epoxy     
     
     
        group present in (B). 15. A composition in accordance with claim 14 
     
     
        wherein compound (B) is a polyepoxide. 16. A composition in accordance with claim 15 wherein component (A) is a hydroxy-functional organopolysiloxane of the formula ##EQU4## in which R 4  is a monovalent hydrocarbon radical selected from the group consisting of alkyl radicals of from 1 to 6 inclusive carbon atoms and the phenyl radical; R 5  is an alkyl radical of from 1 to 6 inclusive carbon atoms; a is an integer having a value of 1 or 2; b having a value of 0 or 1, the sum of a+b being no more than 2; c is an integer having a value of 1 or 2, d is an integer having a value of from 1 to 3; e having a value of 0 to 2, the sum of d+e being no more than 3; x having a 
     
     
        value of at least 1 and y having a value of 0 or more. 17. A composition in accordance with claim 16 wherein the organopolysiloxane (A) is present in an amount sufficient to provide from 0.5 to 1.5 ═SiOH per epoxy 
     
     
        group present in (B). 18. A composition in accordance with claim 16 wherein said organopolysiloxane is a phenylpolysiloxane resin having a degree of substitution of from 1.0 to 1.7; a phenyl to silicon ratio of 0.2 to 1.5 and a silicon-bonded hydroxy content of from 2.5 to 10 weight 
     
     
        percent. 19. A composition in accordance with claim 18 wherein the polyepoxide .[.(b).]. .Iadd.(B) .Iaddend.is selected from the group consisting of the glycidyl ethers of polyphenols and cycloaliphatic 
     
     
        polyepoxides. 20. A composition in accordance with claim 19 wherein the phenylpolysiloxane resin is of the formula ##EQU5## in which R is an alkyl of from 1 to 3 inclusive carbon atoms, a has an average value of from 1.0 to 1.7, the phenyl to silicon ratio being in the range of 0.2 to 1.5, the silicon-bonded hydroxyl content of said resin 
     
     
        being in the range of 2.5 to 7.5 weight percent. 21. A composition in 
     
     
        accordance with claim 19 containing a solid filler. 22. A composition in accordance with claim 21 wherein the filler is present in an amount in the range of 30 to 90 weight percent based on the total weight of the 
     
     
        composition. 23. A composition in accordance with claim 22 wherein the 
     
     
        filler includes granular fused silica and glass fibers. 24. A composition in accordance with claim 20 wherein the aluminum catalyst (C) is an aluminum acylate of the formula ##STR45## 
     
     
        25. A composition in accordance with claim 24 comprising A. from 10 to 60 weight percent of the phenyl polysiloxane resin B. from 49 to 90 weight percent of the polyepoxide   C. from 0.1 to 5 weight percent, based on the combined weight of (A) and   
     
     
        (B) of aluminum acylate catalyst. 26. A composition in accordance with claim 25 wherein the polyepoxide is an epoxy functional cresol novalac resin. .[.27. A composition in accordance with claim 25 wherein the 
     
     
        polyepoxide is the diglycidyl ether of bisphenol A..]. 28. A composition in accordance with claim 25 wherein the polyepoxide is a cycloaliphatic 
     
     
        polyepoxide having an epoxide equivalent of more than 65. 29. A composition in accordance with claim 25 wherein the aluminum acylate (C) is selected from the group consisting of aluminum stearates and aluminum 
     
     
        benzoates. 30. A cured composition in accordance with claim 15. 31. A composition in accordance with claim 14 wherein the aluminum compound is of the formula 
     
     
       Al(OR) 3  32. A composition in accordance with claim 14 in which the aluminum compound is of the formula ##STR46## 
     
     
        33. A composition in accordance with claim 14 wherein the aluminum compound is of the formula 
     
     
       H +  Al -  (OR) 4  34. A composition in accordance with claim 14 wherein the aluminum compound is of the formula 
     
     
       .tbd.AlOSiR 3   2  35. A composition in accordance with claim 14 
     
     
        wherein the aluminum compound is an aluminum chelate. 36. A composition in accordance with claim 14 wherein at least a portion of the epoxide comprise a brominated epoxy compound.