Silicone hydrogels having consistent concentrations of multi-functional polysiloxanes

1. A process comprising forming a monomer mixture comprising at least one monofunctional silicone containing component which comprises at least one difunctional byproduct; determining the concentration of said difunctional byproduct in said monofunctional silicone containing component; and adding to said monomer mixture a normalizing amount of said at least one difunctional byproduct and curing said monomer mixture to form a biomedical device.

2. The process of claim 1 wherein said normalizing amount is between about 0.1 and about 5%, based upon the weight of said monofunctional silicone-containing component.

3. The process of claim 1 wherein said normalizing amount is between about 1 and about 3%, based upon the weight of said monofunctional silicone-containing component.

4. The process of claim 1 wherein said monofunctional silicone containing component is selected from the group consisting of polysiloxanylalkyl(meth)acrylic monomers, hydroxyl functionalized silicone-containing monomers, poly(organosiloxane) prepolymer, vinyl carbonate monomers, vinyl carbamate monomers, polysiloxanes with a polar fluorinated graft or side group having a hydrogen atom attached to a terminal difluoro-substituted carbon atom and combinations thereof.

5. The process of claim 1 wherein said monofunctional silicone containing component comprises a polysiloxanylalkyl(meth)acrylic monomers of Formula I

wherein: R 12 is H or lower alkyl;

X is O or NR 16 ; R 16 is independently selected from the group consisting of hydrogen or lower alkyl,

each R 13 -R 15 is independently selected from the group consisting of lower alkyl radical or a phenyl radical, and b is 1 or 3 to 10.

6. The process of claim 1 wherein said wherein said monofunctional silicone-containing component is selected from the group consisting of methacryloxypropyl tris(trimethylsiloxy) silane, pentamethyldisiloxanyl methylmethacrylate, and methyldi(trimethylsiloxy)methacryloxymethyl silane.

7. The process of claim 1 wherein said wherein said monofunctional silicone-containing component comprises methacryloxypropyl tris(trimethylsiloxy)silane.

8. The process of any of claims 1 , 6 , or 7 wherein said difunctional silicone-containing byproduct comprises bis(trimethylsiloxy)methylsilylpropyl-1,2-dimethacrylate.

9. The process of claim 1 wherein said monofunctional silicone containing component is a hydroxyl-functionalized silicone containing monomer of Formula I

wherein:

R 1 is selected from the group consisting of hydrogen and C 1-6 alkyl;

R 2 , R 3 , and R 4 , are independently selected from the group consisting of C 1-6 alkyl, triC 1-6 alkylsiloxy, phenyl, naphthyl, substituted C 1-6 alkyl, substituted phenyl, or substituted naphthyl

R 5 is hydroxyl, an alkyl group containing one or more hydroxyl groups; or (CH 2 (CR 9 R 10 ) y O) x )—R 11 wherein y is 1 to 5, x is an integer of 1 to 100; R 9 -R 11 are independently selected from the group consisting of H, alkyl having up to 10 carbon atoms and alkyls having up to 10 carbon atoms substituted with at least one polar functional group,

R 6 is a divalent group comprising up to 20 carbon atoms;

R 7 is a monovalent group that can polymerize under free radical and/or cationic polymerization and comprising up to 20 carbon atoms; and

R 8 is a divalent group comprising up to 20 carbon atoms.

10. The process of claim 9 wherein R 1 is hydrogen,

R 2 , R 3 , and R 4 are independently selected from the group consisting of C 1-6 alkyl and triC 1-6 alkylsiloxy;

R 5 selected from the group consisting of hydroxyl, —CH 2 OH or CH 2 CHOHCH 2 OH;

R 6 is selected from the group consisting of divalent C 1-6 alkyl, C 1-6 alkyloxy, C 1-6 alkyloxyC 1-6 alkyl, phenylene, naphthalene, C 1-12 cycloalkyl, C 1-6 alkoxycarbonyl, amide, carboxy, C 1-6 alkylcarbonyl, carbonyl, C 1-6 alkoxy, substituted C 1-6 alkyl, substituted C 1-6 alkyloxy, substituted C 1-6 alkyloxyC 1-6 alkyl, substituted phenylene, substituted naphthalene, substituted C 1-12 cycloalkyl, where the substituents are selected from one or more members of the group consisting of C 1-6 alkoxycarbonyl, C 1-6 alkyl, C 1-6 alkoxy, amide, halogen, hydroxyl, carboxyl, C 1-6 alkylcarbonyl and formyl;

R 7 is selected from the group consisting of acrylate, styryl, vinyl, vinyl ether, itaconate group, C 1-6 alkylacrylate, acrylamide, C 1-6 alkylacrylamide, N-vinyllactam, N-vinylamide, C 2-12 alkenyl, C 2-12 alkenylphenyl, C 2-12 alkenylnaphthyl, C 2-6 alkenylphenylC 1-6 alkyl, vinyl ether and epoxide groups;

R 8 is selected from the group consisting of divalent C 1-6 alkyl, C 1-6 alkyloxy, C 1-6 alkyloxyC 1-6 alkyl, phenylene, naphthalene, C 1-12 cycloalkyl, C 1-6 alkoxycarbonyl, amide, carboxy, C 1-6 alkylcarbonyl, carbonyl, C 1-6 alkoxy, substituted C 1-6 alkyl, substituted C 1-6 alkyloxy, substituted C 1-6 alkyloxyC 1-6 alkyl, substituted phenylene, substituted naphthalene, substituted C 1-2 cycloalkyl, where the substituents are selected from one or more members of the group consisting of C 1-6 alkoxycarbonyl, C 1-6 alkyl, C 1-6 alkoxy, amide, halogen, hydroxyl, carboxyl, C 1-6 alkylcarbonyl and formyl.

11. The process of claim 1 wherein said monofunctional silicone-containing component is selected from the group consisting of (3-methacryloxy-2-hydroxypropyloxy)propylbis(trimethylsiloxy)methylsilane, (2-methacryloxy-3-hydroxypropyloxy)propylbis(trimethylsiloxy)methylsilane, (3-methacryloxy-2-hydroxypropyloxy)propyltris(trimethylsiloxy)silane, 3-methacryloxy-2-(2-hydroxyethoxy)propyloxy)propylbis(trimethylsiloxy)methylsilane, monomethacryloxypropyl terminated mono-n-butyl terminated polydimethylsiloxane, and mixtures thereof.

12. The process of claim 1 wherein said monofunctional silicone-containing component is selected from the group consisting of (3-methacryloxy-2-hydroxypropyloxy)propylbis(trimethylsiloxy)methylsilane), (2-methacryloxy-3-hydroxypropyloxy)propylbis(trimethylsiloxy)methylsilane, monomethacryloxypropyl terminated mono-n-butyl terminated polydimethylsiloxane, and mixtures thereof.

13. The process of claims 9 , 10 , 11 or 12 wherein said difunctional silicone-containing byproduct comprises bis(trimethylsiloxy)methylsilylpropyl-1,2-dimethacrylate.

14. The process of claim 1 wherein said monofunctional silicone-containing component is present in an amount between about 25 and about 60 weight %, based upon weight of all reactive components in the monomer mixture.

15. The process of claim 1 wherein said monomer mixture further comprises at least one hydrophilic component.

16. The process of claim 15 wherein said hydrophilic component is present in an amount between about 10 and about 60%, based upon weight of all reactive components in the monomer mixture.

17. The process of claim 15 wherein said hydrophilic component is selected from the group consisting of N,N-dimethyl acrylamide, 2-hydroxyethyl acrylate, glycerol methacrylate, 2-hydroxyethyl methacrylamide, N-vinylpyrrolidone, polyethyleneglycol monomethacrylate, and mixtures thereof.

18. The process of claim 15 wherein said hydrophilic component is selected from the group consisting of N,N-dimethyl acrylamide, 2-hydroxyethyl macrylate and mixtures thereof.

19. The process of claim 1 wherein said monofunctional silicone containing component comprises (3-methacryloxy-2-hydroxypropyloxy)propylbis(trimethylsiloxy)methylsilane, monomethacryloxypropyl terminated mono-n-butyl terminated polydimethylsiloxane and mixtures thereof, said at least one difunctional byproduct comprises bis(trimethylsiloxy)methylsilylpropyl-1,2-dimethacrylate and said monomer mixture further comprises at least one high molecular weight hydrophilic polymer, and at least one hydrophilic component is selected from the group consisting of N,N-dimethyl acrylamide, 2-hydroxyethyl macrylate and mixtures thereof.

20. The process of claim 1 wherein said biomedical device is an ophthalmic device.

21. The process of claim 1 wherein said biomedical device is a contact lens.

22. The process of claim 1 wherein only one difunctional byproduct is added to said monomer mixture.