Material based on crosslinked silicone polymer comprising an immobilized photoinitiator, process for the preparation thereof, hydrophilic polymeric product obtained from this material and process for the preparation thereof, and novel photoinitiators

Abstract

This invention pertains to a process for the manufacture of a hydrophilic polymeric product, consisting in causing a material comprising a crosslinked silicone polymer matrix and photoinitiator groups dispersed and immobilized within the polymer matrix to swell in a swelling solution comprising a solvent for swelling the crosslinked silicone polymer of the matrix of the material, a photopolymerizable hydrophilic monomer and optionally a crosslinking agent and a proton- or electron-donating coinitiator compound, when the material comprises photoactivable photoinitiator groups and does not comprise proton- or electron-donating coinitiator groups causing the photopolymerizable hydrophilic monomer to diffuse into the swollen material, and polymerizing, by irradiation, the photopolymerizable hydrophilic monomer.

1 . Material based on crosslinked silicone polymer, characterized in that it comprises a crosslinked silicone polymer matrix and photoinitiator groups which are dispersed and attached within the silicone matrix.  
     
     
         2 . Material according to    claim 1   , characterized in that the photoinitiator groups are attached to the crosslinked silicone polymer constituting the matrix via covalent Si—C bonds.  
     
     
         3 . Material according to    claim 1   , characterized in that the photoinitiator groups are carried by a long-chain compound dispersed and physically immobilized within the matrix.  
     
     
         4 . Material according to    claim 3   , characterized in that the long-chain compound is a polydimethylsilane (PDMS).  
     
     
         5 . Material according to any one of the preceding claims, characterized in that the photoinitiator groups are photocleavable groups.  
     
     
         6 . Material according to any one of    claims 1    to    4   , characterized in that the photoinitiator groups are photoactivable groups.  
     
     
         7 . Material according to    claim 6   , characterized in that it additionally comprises proton- or electron-donating coinitiator groups.  
     
     
         8 . Material according to    claim 7   , characterized in that the coinitiator groups are attached chemically to the crosslinked silicone polymer of the matrix.  
     
     
         9 . Material according to    claim 7   , characterized in that the coinitiator groups are carried by a long-chain compound dispersed and immobilized within the matrix.  
     
     
         10 . Material according to any one of the preceding claims, characterized in that the crosslinked silicone polymer of the matrix is a polydimethylsiloxane.  
     
     
         11 . Material according to    claim 10   , characterized in that the crosslinked silicone polymer of the matrix results from the thermal polymerization of a mixture of an oil of a polysiloxane monomer or oligomer carrying Si-vinyl groups and of an oil of a polysiloxane monomer or oligomer carrying Si—H groups in the presence of a hydrosilylation catalyst.  
     
     
         12 . Material according to    claim 11   , characterized in that the mixture of the polysiloxane oils comprises 0.8 to 1.9 Si—H bonds per 1 Si-vinyl bond.  
     
     
         13 . Functionalized photoinitiator, characterized in that it corresponds to the formula:  
                   
       in which: 
 R represents a hydrogen atom or a methyl group, Z is a divalent hydrocarbon-comprising chain comprising from 1 to 10 carbon atoms which can be interrupted by 1 to 3 atoms chosen from —O— and  
                 
 
 where R′ is independently a hydrogen atom or a C 1 -C 6  alkyl group,  
 and  
 A m  is a radical chosen from the radicals of formulae:  
                 
 
 provided that Z comprises at least two carbon atoms;  
                 
 
 in which R 1 , R 2 , R 3  and R 4 , which are identical or different, represent a hydrogen atom or a C 1 -C 6  alkyl radical.  
 
     
     
         14 . Photoinitiators according to    claim 13   , characterized in that Z is a divalent chain chosen from the group consisting of  
                   
       in which R″ and R″′ represent, independently of one another, a C 1 -C 6  alkyl group, n 1  and n 2  are integers from 1 to 6, n 3  and n 5  are integers from 0 to 4, n 4  is equal to 0 or 1, and n 6  is an integer from 0 to 5.  
     
     
         15 . Photoinitiator corresponding to the formula:  
                   
     
     
         16 . Photoinitiators corresponding to the formulae:  
                   
     
     
         17 . Macrophotoinitiators, characterized in that they result from the reaction between a hydrodimethylpolysiloxane and a compound according to any one of    claims 13    to    16   .  
     
     
         18 . Process for the manufacture of a material according to    claim 1   , characterized in that it consists in mixing, with a crosslinkable liquid composition comprising an oil of a polysiloxane monomer or oligomer carrying Si-vinyl groups, an oil of a polysiloxane monomer or oligomer carrying Si—H groups and a hydrosilylation catalyst, a compound comprising one or more photoinitiator groups, and in crosslinking the mixture without the photoinitiator groups participating in the crosslinking.  
     
     
         19 . Process according to    claim 18   , characterized in that the compound comprising the photoinitiator groups becomes attached via covalent bonds to silicon atoms of the polysiloxane oils during the crosslinking.  
     
     
         20 . Process according to    claim 19   , characterized in that the compound comprising the photoinitiator groups is chosen from the compounds defined in any one of    claims 13    to    16   .  
     
     
         21 . Process according to    claim 18   , characterized in that the compound comprising the photoinitiator groups is a long-chain compound.  
     
     
         22 . Process according to    claim 21   , characterized in that the compound comprising the photoinitiator groups is a compound according to    claim 17   .  
     
     
         23 . Process according to    claim 18   , characterized in that the photoinitiator groups are photoactivable groups.  
     
     
         24 . Process according to    claim 23   , characterized in that a proton- or electron-donating coinitiator compound is added to the crosslinkable liquid composition.  
     
     
         25 . Process according to    claim 24   , characterized in that the coinitiator compound is a compound functionalized in order to become attached via covalent bonding to silicon atoms of the oils during the crosslinking.  
     
     
         26 . Process according to    claim 24   , characterized in that the coinitiator compound is a long-chain compound.  
     
     
         27 . Process for the manufacture of a hydrophilic polymeric product, characterized in that it consists in: 
 a) causing a material according to any one of    claims 1    to    12    to swell in a swelling solution comprising a solvent for swelling the crosslinked silicone polymer of the matrix of the material, a photopolymerizable hydrophilic monomer and optionally: 
 1) a crosslinking agent; and  
 2) a proton- or electron-donating coinitiator compound, when the material based on crosslinked silicone polymer comprises photoactivable photoinitiator groups and does not comprise proton- or electron-donating coinitiator groups;  
   b) causing the photopolymerizable hydrophilic monomer to diffuse into the swollen material; and    c) polymerizing, by irradiation, the photopolymerizable hydrophilic monomer.    
     
     
         28 . Process according to    claim 27   , characterized in that the photopolymerizable hydrophilic monomer is chosen from acrylic acid, methacrylic acid and hydroxyalkyl (meth)acrylates.  
     
     
         29 . Process according to    claim 27    or    28   , characterized in that the hydrophilic monomer/solvent ratio is less than 0.5, preferably less than 0.2.  
     
     
         30 . Process according to any one of    claims 27    to    29   , characterized in that the solvent is chosen from toluene, cyclohexane, dodecane, tetrahydrofuran and fluorinated solvents.  
     
     
         31 . Process according to any one of    claims 27    to    30   , characterized in that the polymerization of the swollen material is carried out outside the swelling solution.  
     
     
         32 . Process according to any one of    claims 27    to    30   , characterized in that the polymerization of the swollen material is carried out with the material immersed in the swelling solution.  
     
     
         33 . Hydrophilic polymeric product obtained by the process according to    claim 27   , in which the photoinitiator groups are attached to [sic] covalent bonds to silicon atoms of the crosslinked silicone polymer of the matrix, and characterized in that the hydrophilic polymer obtained after photopolymerization of the polymerizable hydrophilic monomer is, at least partially, grafted to the crosslinked silicone polymer of the matrix.