WATER BORNE CROSSLINKABLE BLOCK COPOLYMERS OBTAINED USING RAFT

1 . A process for obtaining a water-borne non-biologically active crosslinkable composition comprising a block copolymer comprising at least blocks [A] x [B] y and a polymer P, the block copolymer-polymer composition having an acid value <150 mg KOH per g of block copolymer-polymer, where at least block [A] and [B] is obtained by a controlled radical polymerisation of at least one ethylenically unsaturated monomer via a reversible addition-fragmentation chain transfer (RAFT) mechanism in solution in the presence of a control agent and a source of free radicals;

where block [A] comprises:

i) 0 to 50 mol % of ethylenically unsaturated monomer units bearing crosslinking functional groups;

ii) 50 to 100 mol % ethylenically unsaturated monomer units bearing water-dispersing functional groups;

iii) 0 to 50 mol % of ethylenically unsaturated monomers units selected from C 1-18 alkyl(meth)acrylate monomers and styrenic monomers;

iv) 0 to 35 mol % of ethylenically unsaturated monomers units different from those from i), ii) iii);

where i), ii), iii)+iv) add up to 100%;

block [A] has a Hansch parameter <1.5; and

block [A] has an average degree of polymerisation x, where x is an integer from 3 to 80;

where block [B] comprises:

i) 5 to 80 mol % of ethylenically unsaturated monomer units bearing crosslinking functional groups;

ii) 0 to 20 mol % of ethylenically unsaturated monomer units bearing water-dispersing functional groups;

iii) 20 to 95 mol % of ethylenically unsaturated monomers units selected from C 1-18 alkyl(meth)acrylate monomers and styrenic monomers;

iv) 0 to 35 mol % of ethylenically unsaturated monomers units different from those from i), ii)

where i), ii), iii)+iv) add up to 100%;

block [B] has a Hansch parameter >1.5; and

block [B] has an average degree of polymerisation y, where y is an integer >10, where y>x; and

where the polymer P is obtained in the presence of the block copolymer by an emulsion polymerization process; and comprises:

i) 0 to 5 wt % of ethylenically unsaturated monomer units bearing crosslinking functional groups;

ii) 0 to 5 wt % of ethylenically unsaturated monomer units bearing water-dispersing functional groups;

iii) 80 to 100 wt % of ethylenically unsaturated monomers units selected from C 1-18 alkyl(meth)acrylate monomers and styrenic monomers;

iv) 0 to 10 wt % of ethylenically unsaturated monomers units different from those from 1), ii) iii);

where i), ii), iii)+iv) add up to 100%.

2 . A process according to claim 1 where:

block [A] comprises:

(i) 0 to 20 mol % of ethylenically unsaturated monomer units bearing crosslinking functional groups;

iii) 0 to 50 mol % of ethylenically unsaturated monomers units selected from C 1-12 alkyl (meth)acrylate monomers and styrenic monomers; and

iv) 0 to 20 mol %, of ethylenically unsaturated monomers units different from those from i), ii) iii);

block [B] comprises:

iii) 20 to 95 mol % of ethylenically unsaturated monomers units selected from C 1-12 alkyl(meth)acrylate monomers and styrenic monomers; and

iv) 0 to 20 mol % of ethylenically unsaturated monomers units different from those from i), ii) iii); and

the polymer P comprises:

iii) 80 to 100 wt % of ethylenically unsaturated monomers units selected C 1-12 alkyl(meth)acrylate monomers and styrenic monomers.

3 . A process according to claim 1 , where the number average molecular weight of the block copolymer is in the range of from 1,000 to 50,000 g/mol.

4 . A process according to claim 1 , where the weight average molecular weight of the polymer P is >50,000 g/mol.

5 . A process according to claim 1 , wherein polymer P is more hydrophobic than block [A].

6 . A process according to claim 1 , wherein the wt % of blocks [A][B] together is in the range of from 0.5 to 50% based on the weight of blocks [A][B] and polymer P.

7 . A process according to claim 1 , where at least 20 wt % of polymer P is covalently bonded to the block copolymer.

8 . A process according to claim 1 , wherein the control agent is selected from the group consisting of dithioesters, thioethers-thiones, trithiocarbonates, dithiocarbamates, xanthates and mixtures thereof.

9 . A polymeric composition obtained and/or obtainable by the process claimed in claim 1 .

10 . A water-borne composition comprising the block copolymer-polymer prepared or a polymeric composition of claim 9 , additionally comprising a separate crosslinking agent.

11 . An ink, paint or adhesive comprising the block-copolymer-polymer or a polymeric composition of claim 9 .

12 . Use of a formulation comprising the block copolymer-polymer prepared or a polymeric composition of claim 9 , to coat a substrate.