Methacrylate-based bulky side-chain siloxane cross linkers for optical medical devices

Abstract

Novel polymers for biomedical use, especially rigid gas permeable contact lenses that are based on bulky side-chain siloxane cross linkers. The siloxanes, either alone, or as copolymers with bulky and non-bulky mono-functional polymerizable siloxanes, fluoro monomers, such as hexafluoroisopropyl methacrylate, and hydrophilic monomers, result in transparent, high oxygen permeable polymers possessing excellent lathing and milling characteristics.

1 . A contact lens that is the polymerization product of a monomeric mixture comprising a bulky side-chain siloxane cross linker and one or more comonomers. 
     
     
         2 . The contact lens of  claim 1 , herein the bulky side chain siloxane cross linker has the following structural formula: 
       
         
           
           
               
               
           
         
         wherein z is 2-10, n, p and z are integers, X is oxygen, sulfur or —NH—, y is 0 or 1, R* is independently alkyl, arylalkyl, cycloalkyl, heterocyclo or fluoroalkyl, trialkyl or triarylsilyl, or trialkoxyl or triaryloxysilane radical, A is activated unsaturation such as acrylate, methacrylate, acrylamido, styryl, maleimideo, itacanoyl, vinyl, vinyl ether, vinyl carbonate, and R is independently alkyl, arylalkyl cycloalkyl, heterocyclo or fluoroalkyl radical. 
       
     
     
         3 . The contact lens of  claim 1  wherein the comonomers are hydrophilic monomers. 
     
     
         4 . The contact lens of  claim 3  wherein the hydrophilic monomers are selected from the group consisting of (meth)acrylates, 2-hydroxyethyl methacrylate, (meth)acrylamides, methacrylamide, N,N-dimethylacrylamide, (meth)acrylic carboxylic acids, methacrylic acid, vinyl lactams, N-vinylpyrrolidone and mixtures thereof. 
     
     
         5 . The contact lens of  claim 3  wherein the bulky side-chain siloxane cross linker is included in the monomer mixture at 5 to 95 weight percent 
     
     
         6 . The contact lens of  claim 3  wherein the bulky side-chain siloxane cross linker is included in the monomer mixture at 10 to 70 weight percent. 
     
     
         7 . The contact lens of  claim 3  wherein the bulky side-chain siloxane cross linker is included in the monomer mixture at 10 to 50 weight percent. 
     
     
         8 . The contact lens of  claim 1  wherein the monomer mixture further comprises a fluorinated monomer. 
     
     
         9 . The contact lens of  claim 8  wherein the monomer mixture comprises at least one member selected from the group consisting of a fluorinated (meth)acrylate and a fluorinated itaconate. 
     
     
         10 . The contact lens of  claim 1  wherein the monomer mixture further comprises an ethylenically unsaturated monofunctional silicon-containing monomer. 
     
     
         11 . The contact lens of  claim 1  wherein the monomer mixture further comprises a (meth)acrylate monomer. 
     
     
         12 . The contact lens of  claim 11  wherein the monomer mixture comprises an alkyl(meth)acrylate monomer. 
     
     
         13 . The contact lens of  claim 1  wherein the monomer mixture further comprises at least one member selected from the group consisting of a polymerization initiator, an ultraviolet blocking agent, and a colorant. 
     
     
         14 . The contact lens of  claim 1  wherein the monomer mixture comprises: the bulky side-chain siloxane cross linker; a hydrophilic monomer; a fluorinated monomer; an ethylenically unsaturated monofunctional silicon-containing monomer; a (meth)acrylate monomer; and at least one member selected from the group consisting of a polymerization initiator, an ultraviolet blocking agent, and a colorant. 
     
     
         15 . A copolymer useful as a rigid gas permeable contact lens material that is the polymerization product of a monomeric mixture comprising a bulky side-chain siloxane cross linker. 
     
     
         16 . The copolymer of  claim 15  having a toughness of at least 1.5 Mpa·mm/mm and an oxygen permeability of at least 100 barrers, and being optically clear. 
     
     
         17 . The copolymer of  claim 16  having an oxygen permeability of at least 140 barrers. 
     
     
         18 . The copolymer of  claim 15  wherein the monomer mixture comprises: the bulky side chain siloxane cross linker; a fluorinated monomer; an ethylenically unsaturated monofunctional silicon-containing monomer; a hardness modifying (meth)acrylate monomer; and at least one member selected from the group consisting of a polymerization initiator, an ultraviolet blocking agent, and a colorant. 
     
     
         19 . The copolymer of  claim 15  having the shape of a cylindrical disk. 
     
     
         20 . A combination comprising: a cylindrical disk formed from a copolymer that is the polymerization product of a monomeric mixture comprising a polysiloxane-containing urethane or urea prepolymer end-capped with polymerizable ethylenically unsaturated radicals; and packaged with the disk, printed instructions for lathing a rigid gas permeable contact lens from the disk.