Polymeric surface coatings

A process in which a substrate having a surface which bears substrate pendant functional groups is coated with a coating composition containing a polymer formed from a radical polymerisable monomers including a radical polymerisable zwitterionic monomer and a radical polymerisable monomer containing a reactive group to form a polymer having zwitterionic groups and pendant reactive groups and the said pendant reactive groups are reacted to form covalent bonds with said substrate pendant functional group and thereby form a stable coating of polymer on the said surface, and wherein

• said zwitterionic monomer has the general formula I
• Y-B-X (I)
• wherein B is a straight or branched alkylene, oxaalkylene or oligo-oxaalkylene chain optionally containing one or more fluorine atoms up to and including perfluorinated chains, or if X contains a carbon-carbon chain between B and the centre of permanent position charge or if Y contains a terminal carbon atom bonded to B, a valence bond;
• X is a zwitterionic group selected from groups IVB, IVC, IVD, IVE and IVF in which group IVB has the formula
• 30
• wherein the groups R6 are the same or different and each is hydrogen or C1-4 alkyl and d is from 2 to 4;
• group IVC has the formula
• 31
• where the groups R7 are the same or different and each is hydrogen or C1-4 alkyl, and e is from 1 to 4;
• group IVD has the formula
• 32
• wherein the groups R8 are the same or different and each is hydrogen or C1-4 alkyl, R8a is hydrogen or a group —C(O)B1R8b wherein R8b is hydrogen or methyl, B1 is a valence bond or straight or branched alkylene, oxaalkylene or oligo-oxaalkyene group, and f is from 1 to 4;
• and if B is other than a valence bond z is 1 and if B is a valence bond z is 0, if X is directly bonded to an oxygen or nitrogen atom and otherwise z is 1;
• group IVE has the formula
• 33
• wherein the groups R9 are the same or different and each is hydrogen or C1-C4 alkyl, R9a is hydrogen or a group —C(O)B2R9b, wherein R9b is hydrogen or methyl, B2 is a valence bond or a straight or branched alkylene, oxaalkylene or oligo-oxaalkylene group, and g is from 1 to 4;
• and
• if B is other than a valence bond z is 1 and if B is a valence bond z is 0 if X is directly bonded to an oxygen or nitrogen atom and otherwise z is 1;
• and
• group IVF has the formula
• 34
• wherein the groups R10 are the same or different and each is hydrogen or C1-4 alkyl, R10a is hydrogen or a group —C(O)B3R10b wherein R10b is hydrogen or methyl, B3 is a valence bond or a straight or branched alkylene, oxaalkylene or oligo-oxaalkylene group, and h is from 1 to 4;
• and
• if B is other than a valence bond z is 1 and if B is a valence bond z is 0 if X is directly bonded to the oxygen or nitrogen and otherwise z is 1;
• and
• Y is an ethylenically unsaturated polymerisable group selected from
• 35
• wherein:
• R is hydrogen or a C1-C4 alkyl group;
• A is —O— or —NR1— where R1 is hydrogen or a C1-C4 alkyl group or R1 is -B-X where B and X are as defined above;
• and
• K is a group —(CH2)pOC(O)—, —(CH2)pC(O)O—, —(CH2)pOC(O)O—, —(CH2)pNR2—, —(CH2)pNR2C(O)—, —CH2)pC(O)NR2—, —(CH2)pNR2C(O)O—, —(CH2)OC(O)NR2—, —(CH2)pNR2C(O)NR2—, (in which the groups R2 are the same or different) —(CH2)pO—, —(CH2)pSO3—, or, optionally in combination with B, a valence bond and p is from 1 to 12 and R2 is hydrogen or a C1-C4 alkyl group, and
• said radical polymerisable monomer containing reactive groups has the formula general formula (XII)
• Y2-B7-Q3 (XII)
• where Y2 is an ethylenically unsaturated polymerisable group selected from
• 36
• where R26 is hydrogen or C1-C4 alkyl;
• T is —O— or NR27—, wherein R27 is hydrogen or a C1-C4 alkyl group or R27 is a group -B7Q3;
• B7 is a valence bond a straight or branched alkylene oxaalkylene or oligo-oxaalkylene group;
• K2 is a group —(CH2)qOC(O)—, —(CH)qC(O)O—, —(CH2)qOC(O)O—, —(CH2)qNR20—, —(CH2)qNR20C(O)—, —(CH2)qC(O)NR20—, —(CH2)NR20C(O)O—, —(CH2)qOC(O)NR20—, —(CH2)qNR20C(O)NR20— (in which the groups R20 are the same or different), —(CH2)qO—, or —(CH2)qSO3—, or a valence bond and q is from 1 to 12 and R20 is hydrogen or a C1-C4 alkyl group;
• and
• Q3 is a reactive group selected from the group consisting of aldehyde groups;
• silane and siloxane groups containing one or more substituents selected from halogen atoms and C1-4-alkoxy groups;
• hydroxyl;
• amino;
• carboxyl;
• epoxy;
• —CHOHCH3Hal (in which Hal is selected from chlorine, bromine and iodine atoms);
• succinimido;
• tosylate;
• triflate;
• imidazole carbonyl amino;
• optionally substituted triazine groups;
• aceloxy;
• mesylate;
• carbonyl di(cyclo)alkyl carbodiimidoyl;
• and oximino.