Copolymer comprising units of type a deriving from carboxylic acid monomers and units of type b deriving from sulfonic acid monomers

1. A diblock copolymer comprising units of type A deriving from carboxylic acid monomers and units of type B deriving from sulfonic acid monomers, said units of type A and B representing more than 80 mol % of the total moles of units in the copolymer,

wherein the diblock copolymer further comprises at least:

one first block, wherein the first block consists of units of type A, and optionally one or more reversible chain transfer agents and optionally one or more initiator fragments, and having a degree of polymerization DP 1 comprised between 5 and 150; and

one second block formed of at least 95 mol % of units of type A and B with a molar ratio of units of type A to units of type B being greater or equal to 1, wherein said units of type A and units of type B are statistically distributed, said second block having a degree of polymerization DP 2 such that DP 2 /DP 1 >1,

wherein the units of type A derive from monomers selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, alpha-chloro-acrylic acid, bromo acrylic acid, bromomethyl acrylic acid, alpha-cyano acrylic acid, beta methyl-acrylic acid, alpha-phenyl acrylic acid, beta-acryloxy propionic acid, beta-carboxyethyl acrylic acid, sorbic acid, alpha-chloro sorbic acid, angelic acid, cinnamic acid, p-chloro cinnamic acid, beta-styryl acrylic acid, itaconic acid, maleic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, fumaric acid, vinyl benzoic acid, pentenic acid, propyl acrylic acid, acetamido acrylic acid, maleimido propyl carboxylic acid, and mixtures thereof, and

wherein the units of type B derive from monomers selected from the group consisting of acrylamido-2-methylpropanesulfonic acid, 2-methacrylamido-2-methylpropanesulfonic acid, 3-methyacrylamido-2-hydroxypropanesulfonic acid, (meth)allylsulfonic acid, 1-allyloxy-2-hydroxypropane sulfonic acid, allyloxybenzene sulfonic acid, (meth)allyloxybenzensulfonic acid, 2-hydroxy-3-(2-propenyloxy)propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, styrene sulfonic acid, vinylsulfonic acid, 3-sulfopropyl acrylate, 3-sulfopropyl methacrylate, sulfomethylacrylamid, sulfomethylmethacrylamid, water soluble salts thereof, and mixtures thereof.

2. The copolymer according to claim 1 , wherein the ratio DP 2 /DP 1 is less than or equal to 1,000.

3. The copolymer according to claim 1 , wherein the first block has a degree of polymerization DP 1 greater than or equal to 10 and up to 150.

4. The copolymer according to claim 1 , wherein the second block has a degree of polymerization DP 2 less than or equal to 2,000.

5. The copolymer according to claim 1 , wherein the molar ratio of units of type A to units of type B in the second block ranges from 50/50 to 90/10.

6. A diblock copolymer pAA-b-(pAA/AMPS 75/25) comprising units of type A deriving from acrylic acid monomers and units of type B deriving from acrylic acid and 2-acrylamido-2-methylpropane sulfonate monomers with a molar ratio of type A units to type B units of 75/25.

7. The copolymer according to claim 1 , wherein said units of type A of the first block are identical to said units of type A of the second block.

8. The copolymer according to claim 1 , wherein the units of type A of the first block, the second block, or both derive from acrylic acid monomer.

9. The copolymer according to claim 1 , wherein the units of type B derive from 2-acrylamido-2-methylpropanesulfonate monomer or sodium vinyl sulfonate monomer.

10. The copolymer according to claim 1 , wherein said units of type A derive from acrylic acid monomer and said units of type B derive from 2-acrylamido-2-methylpropanesulfonate monomer.

11. The copolymer according to claim 1 , wherein the copolymer is a diblock copolymer consisting of one first block and one second block.

12. The copolymer according to claim 11 , wherein said diblock copolymer consists of:

one first block deriving from acrylic acid monomers with a degree of polymerization DP 1 comprised between 50 and 65; and

one second block that is a statistical block deriving from acrylic acid (AA) and 2-acrylamido-2-methylpropanesulfonate (AMPS) monomers with a molar ratio of AA units to AMPS units comprised between 50/50 and 80/20, said second block having a degree of polymerization DP 2 comprised between 50 and 250.

13. A detergent composition comprising at least one copolymer according to claim 1 .

14. The detergent composition according to claim 13 , said detergent composition comprising from 0.001 to 10% by weight of said copolymer with respect to the total weight of the detergent composition.

15. A method of making a dishwashing detergent composition comprising adding at least one copolymer according to claim 1 to the dishwashing detergent composition.

16. The copolymer of claim 10 , wherein the copolymer is a diblock copolymer consisting of one first block and one second block.

17. A method of making the copolymer according to claim 1 comprising

Adding a control agent in a controlled polymerization, wherein the control agent is a reversible chain transfer agent.

18. A method of making the copolymer according to claim 1 comprising

Polymerizing the first block in the presence of one or more reversible chain transfer agents, and then a second polymerizing the second block in the presence of one or more second reversible chain transfer agents, wherein the reversible chain transfer agents and second reversible chain transfer agents may be the same or different.

19. A method of making the copolymer according to claim 1 comprising

Reacting type A monomer precursors in presence of one or more reversible chain transfer agents to make the first block, and

Bringing the first block in presence of Type B monomer precursors and polymerizing the second block, and obtaining the copolymer.