Optically transparent hydrogels and processes for their production

Abstract

The invention provides hydrogels for use in the production of biomedical devices. In particular, the invention provides hydrogels formed from siloxane prepolymers and a hydrophilic monomer, which hydrogels are optically transparent.

1. A process for producing a hydrogel comprising:
 a.) polymerizing a hydrophobic siloxane prepoplymer and a silylated hydrophilic monomer; and  
 b.) hydrolyzing the resulting polymer wherein the step a.) polymerizing is carried out by using one of heat polymerization, ultraviolet light polymerization, radiation polymerization, or a combination thereof.  
 
     
     
       2. The process of  claim 1  wherein the hydrophobic siloxane prepolyer and the silylated hydrophilic monomer are polymerized with a hydrophobic siloxane monomer. 
     
     
       3. The process of  claim 2  wherein the hydrophobic siloxane monomer is of the formula: 
                 
 
       wherein R 19  and R 20  are each independently hydrogen or methyl, R 21 , R 22 , and R 23  are each independently a monovalent alkyl of 1 to 5 carbon atoms or aryl, j=1 to 10 and k=0 to 3. 
     
     
       4. The process of  claim 3 , wherein the hydrophobic siloxane monomer is 3-methacryloxypropyltris (trimethylsiloxy)silane or 3-methacryloxypropylbis (trimethylsiloxy)methylsilane. 
     
     
       5. The process of  claim 1  or  3  wherein the hydrophobic siloxane prepolymer is of the formula: 
                 
 
       wherein R 1  is hydrogen or an alkyl of 1 to 5 carbon atoms, R 2  is an alkyl of 1 to 5 carbon atoms, n=1 to 12, and z=1 to 500 and the silylated hydrophilic monomer is of the formula: 
                 
 
       wherein R 24  is hydrogen or methyl, R 25  is hydrogen or methyl, and R 26  is a monoalkyl. 
     
     
       6. The process of  claim 5  wherein the hydrophobic siloxane prepolymer is a α,ω-bismethacryloxypropyl macromer and the silylated hydrophilic monomer is a polyalkylsilyl ether of a hydroxyalkyl(meth)acrylamide. 
     
     
       7. The process of  claim 6  wherein the hydrophobic siloxane prepolymer is α,ω-bismethacryloxypropyl polydimethylsiloxane and the silylated hydrophilic monomer is 2-hydroxymethacrylamide trimethylsilyl ether. 
     
     
       8. A hydrogel comprising a hydrophobic siloxane prepolymer and a silylated hydrophilic monomer. 
     
     
       9. The hydrogel of  claim 8  further comprising a hydrophobic siloxane monomer. 
     
     
       10. The hydrogel of  claim 9  wherein the hydrophobic siloxane monomer is of the formula: 
                 
 
       wherein R 19  and R 20  are each independently hydrogen or methyl, R 21 , R 22 , and R 23  are each independently a monovalent alkyl of 1 to 5 carbon atoms or aryl, j=1 to 10 and k=0 to 3. 
     
     
       11. The hydrogel of  claim 10 , wherein the hydrophobic siloxane monomer is 3-methacryloxypropyltris (methylsiloxy)silane or 3-methacryloxypropylbis (trimethylsiloxy)methylsilane. 
     
     
       12. The hydrogel of  claim 8  or  10  wherein the hydrophobic siloxane prepolymer is of the formula: 
                 
 
       wherein R 1  is hydrogen or an alkyl of 1 to 5 carbon atoms, R 2  is an alkyl of 1 to 5 carbon atoms, n=1 to 12, and z=1 to 500 and the silylated hydrophilic monomer is of the formula: 
                 
 
       wherein R 24  is hydrogen or methyl, R 25  is hydrogen or methyl, and R 26  is a monoalkyl. 
     
     
       13. The hydrogel of  claim 12  wherein the hydrophobic siloxane prepolymer is a α,ω-bismethacryloxypropyl macromer and the silylated hydrophilic monomer is a polyalkylsilyl ether of a hydroxyalkyl(meth)acrylamide. 
     
     
       14. The hydrogel of  claim 13  wherein the hydrophobic siloxane prepolymer is α,ω-bismethacryloxypropyl polydimethylsiloxane and the silylated hydrophilic monomer is 2-hydroxymethacrylamide trimethylsilyl ether. 
     
     
       15. The hydrogel of  claim 8  wherein the hydrophobic siloxane prepolymer is present in an amount of about 5 to about 70 weight percent and the amount of silylated hydrophilic monomer is present in an amount of about 2 to about 60 weight percent. 
     
     
       16. The hydrogel of  claim 9  wherein the amount of siloxane prepolymer used is about 5 to about 70 weight percent, the amount of siloxane monomer used is from about 0 to about 70 weight percent, and the amount of silylated monomer used is from about 2 to about 60 weight percent. 
     
     
       17. The process of  claim 1 , wherein the polymerizing step a.) is carried out using ultraviolet light. 
     
     
       18. The process of  claim 5 , wherein the polymerizing step a.) is carried out using ultraviolet light. 
     
     
       19. The process of  claim 6 , wherein the polymerizing step a.) is carried out using ultraviolet light. 
     
     
       20. The hydrogel of  claim 13  wherein the amount of siloxane prepolymer used is about 5 to about 70 weight percent, the amount of siloxane monomer used is from about 0 to about 70 weight percent, and the amount of silylated monomer used is from about 2 to about 60 weight percent. 
     
     
       21. The hydrogel of  claim 14  wherein the amount of siloxane prepolymer used is about 5 to about 70 weight percent, the amount of siloxane monomer used is from about 0 to about 70 percent, and the amount of silylated monomer used is from about 2 to about 60 weight percent.