Water-soluble or water-dispersible acrylic dispersants obtained by controlled radical polymerization
View Patent ↗The present invention relates to a process for the preparation in aqueous solution of water-soluble acrylic polymers or for the preparation in aqueous dispersion of water-dispersible acrylic co-polymers, polymerised from, the total being 100 mol %: a) 5 to 70 mol % of one or more monomer(s) (A) which are (alkoxy)polyalkylene glycol (meth)acrylates and/or ((alkoxy)polyalkylene glycol)(meth)acrylamides; b) 5 to 95 mol % of one or more unsaturated carboxylic monomer(s) (B); and c) 0 to 85 mol % of one or more hydrophobic monomer(s) (C) which are water insoluble, in the absence of a chain-transfer agent, and in the presence of a sufficient amount of a water-soluble alkoxyamine, until a conversion of at least 90% by weight of the monomers (A), (B) and (C) is obtained. The polymer has a polydispersity index Mw / Mn advantageously <2 and an Mn of between 10 000 g/mol and 50 000 g/mol. Alternately, only some of the monomer (>50%) is converted by the alkoxyamine and the polymerization is completed by a conventional radical initiator. The polymer obtained has a polydispersity index Mw / Mn <6, advantageously <5, preferably <4, and an Mw of between 10 000 g/mol and 500 000 g/mol and advantageously between 30 000 and 150 000 g/mol.
1. A process for the preparation in aqueous solution of water-soluble acrylic polymers or for the preparation in aqueous dispersion of water-dispersible acrylic polymers, comprising
a) copolymerising, the total of the comonomers being 100 mol %:
1) 5 to 70 mol % of one or more monomer(s) (A) which are (alkoxy)polyalkylene glycol (meth)acrylates and/or ((alkoxy)polyalkylene glycol)(meth)acrylamides;
2) 5 to 95 mol % of one or more unsaturated carboxylic monomer(s) (B); and
3) 0 to 85 mol % of one or more hydrophobic monomer(s) (C) which are water insoluble;
in the absence of a chain-transfer agent, in the absence of conventional radical initiators, and in the presence of a sufficient amount of a water-soluble alkoxyamine;
b) terminating the water-soluble alkoxyamine present at a point after the conversion of at least 50% by weight of the monomers (A), (B) and (C) is obtained, but on or before 69% conversion by weight of the monomers (A), (B) and (C); and
c) continuing the polymerisation in the presence of a conventional radical initiator, optionally in the presence of a chain-transfer agent, until a conversion of at least 90% by weight of the monomers (A), (B) and (C) is obtained.
2. The process according to claim 1 , in which the conversion by weight of the monomers (A), (B) and (C) in the presence of alkoxyamine is at least 60% by weight.
3. The process according to claim 1 , in which the proportions of the monomers are:
5 to 50 mol % of monomer(s) (A),
20 to 95 mol % of monomer(s) (B),
0 to 65 mol % of monomer(s) (C).
4. The process according to claim 1 , in which, in (A), the average molecular mass Mn of the polyalkylene glycol side chain is between 350 and 10,000 g/mol.
5. The process according to claim 4 , in which the average molecular mass Mn of the polyalkylene glycol side chain is between 1000 and 6000 g/mol.
6. The process according to claim 1 , in which (A) is selected from the group consisting of methoxypolyethylene glycol acrylate and methoxypolyethylene glycol methacrylate with a polyethylene glycol side chain with a number-average molar mass of between 900 g/mol and 5100 g/mol.
7. The process according to claim 6 , in which the number-average molar mass is between 1800 g/mol and 2200 g/mol.
8. The process according to claim 1 , in which (B) is chosen from acrylic acid and methacrylic acid.
9. The process according to claim 1 , in which (C) is chosen from alkyl methacrylates.
10. The process according to claim 1 , in which the alkoxyamine is chosen from 2-methyl-2-[N-tert-butyl-N-(diethoxy-phosphoryl-2,2-dimethylpropyl)aminoxy]propionic acid and its metal and ammoniacal salts.
11. The process of claim 1 further comprising diluting said solution or dispersion.
12. The process of claim 1 further comprising drying said solution or dispersion to obtain a powder.
13. An aqueous solution or dispersion of respectively water-soluble or water-dispersible acrylic polymer comprising, the total of the comonomers being 100 mol %:
a) 5 to 70 mol % of one or more monomer(s) (A) which are (alkoxy)polyalkylene glycol (meth)acrylates and/or ((alkoxy)polyalkylene glycol)(meth)acrylamides;
b) 5 to 95 mol % of one or more unsaturated carboxylic monomer(s) (B); and
c) 0 to 85 mol % of one or more hydrophobic monomer(s) (C) which are water insoluble;
said polymer having an Mn of between 10,000 g/mol and 50,000 g/mol, wherein said polymer comprises residues of a water-soluble alkoxyamine on 50-69 weight percent of polymer chain ends, and conventional radical initiator residues on 31-50 weight percent of polymer chain ends.
14. The aqueous solution or dispersion according to claim 13 , in which the polymer has a polydispersity index Mw / Mn <2.
15. The aqueous solution or dispersion of claim 13 , wherein said polymer having a polydispersity index Mw / Mn <6 and an Mw of between 10,000 g/mol and 500,000 g/mol.
16. The solution or dispersion according to claim 15 , wherein the polymer has a polydispersity index Mw / Mn <5.
17. The solution or dispersion according to claim 15 , wherein the polymer has a polydispersity index Mw / Mn <4.
18. The solution or dispersion according to claim 15 , wherein Mw is between 30,000 g/mol and 150,000 g/mol.
19. The solution or dispersion according to claim 13 , wherein the proportions of the monomers are:
5 to 50 mol % of monomer(s) (A),
20 to 95 mol % of monomer(s) (B),
0 to 65 mol % of monomer(s) (C).
20. The solution or dispersion according claim 13 , wherein, in (A), the average molecular mass Mn of the polyalkylene glycol side chain is between 350 and 10,000 g/mol.
21. The solution or dispersion according to claim 20 , wherein the average molecular mass Mn of the polyalkylene glycol side chain is between 1000 and 6000 g/mol.
22. The solution or dispersion according to claim 13 , wherein (A) is chosen from methoxypolyethylene glycol acrylate and methoxypolyethylene glycol methacrylate with a polyethylene glycol side chain with a number-average molar mass of between 900 g/mol and 5100 g/mol.
23. The solution or dispersion according to claim 22 , wherein the polyethylene glycol side chain number-average molar mass is between 1800 g/mol and 2200 g/mol.
24. The solution or dispersion according to claim 13 , wherein (B) is chosen from acrylic acid and methacrylic acid.
25. The solution or dispersion according to claim 13 , in which (C) is chosen from alkyl methacrylates.
26. A composition comprising the agueous solution or dispersion of claim 13 , and further comprising: mineral particles.
27. The composition of claim 26 , wherein said mineral particles comprise a cement-based composition.
28. The composition of claim 27 , wherein said cement-based composition comprises a cement grout, mortar, or concrete.
29. The composition of claim 26 further comprising at least one other polymer.
30. A composition comprising the aqueous solution or dispersion of claim 13 , wherein said composition comprises a cosmetic composition, a ceramic composition, or a paint composition.
31. The composition of claim 30 , further comprising at least one other polymer.
32. The aqueous solution or dispersion of claim 13 , wherein the alkoxyamine is selected from the group consisting of 2-methyl-2-[N-tert-butyl-N-(diethoxy-phosphoryl-2,2-dimethylpropyl)aminoxy]propionic acid and its metal and ammoniacal salts.