Liquid (meth)acrylic composition comprising a multistage polymer and a (meth)acrylic monomer, its method of preparation and its use

1. A liquid composition comprising

a) a (meth) acrylic polymer (P1) having a mass average molecular weight Mw of less than 100,000 g/mol,

b) a multistage polymer in in form of core shell particles having a multilayer structure comprising at least one layer (A) comprising a polymer (A1) having a glass transition temperature below 0° C. and another layer (B) comprising a polymer (B1) having a glass transition temperature over 30° C., said layer (A) is made in the first stage of a multistage process forming the core for the polymer particle having the multilayer structure and

c) a (meth)acrylic monomer (M1)

wherein the multistage polymer to monomer ratio by weight in the liquid composition is between 1/99 and 25/75.

2. The composition according to claim 1 , wherein the (meth) acrylic polymer (P1) has a mass average molecular weight Mw of less than 50,000 g/mol.

3. The composition according to claim 1 , wherein the (meth) acrylic polymer (P1) has a mass average molecular weight Mw above 5,000 g/mol.

4. The composition according to claim 1 , wherein the (meth) acrylic polymer (P1) has a mass average molecular weight Mw between 5,000 g/mol. and 70,000 g/mol.

5. The composition according to claim 1 , wherein the multistage polymer to monomer ratio by weight in the liquid composition is between 2/98 and 24/76.

6. The composition according to claim 1 , wherein the (meth) acrylic polymer (P1) is soluble in the (meth)acrylic monomer (M1).

7. The composition according to claim 1 , wherein the monomer (M1) is from the group consisting of acrylic acid, methacrylic acid, alkyl acrylic monomers, and alkyl methacrylic monomers and mixtures thereof wherein the alkyl group has from 1 to 22 carbons that are either linear, branched or cyclic.

8. The composition according to claim 1 , wherein the monomer (M1) is chosen is selected from the group consisting of methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, methacrylic acid, acrylic acid, n-butyl acrylate, iso-butyl acrylate, n-butyl methacrylate, iso-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate and mixtures thereof.

9. The composition according to claim 1 , wherein the stage (A) is the first stage and that stage (B) comprising polymer (B1) is grafted on stage (A) comprising polymer (A1).

10. The composition according to claim 1 , wherein the polymers (A1) and (B1) are acrylic or methacrylic polymers.

11. The composition according to claim 1 , wherein the polymer (A1) comprises at least 50 wt % of polymeric units coming from isoprene or butadiene.

12. The composition according to claim 1 , wherein the (meth) acrylic polymer (P1) comprises at least 50 wt % monomers chosen from C1 to C12 alkyl (meth)acrylates.

13. The composition according to claim 1 , wherein the (meth) acrylic polymer (P1) comprises from 50 wt % to 100 wt % methyl methacrylate.

14. The composition according to claim 1 , wherein the (meth) acrylic polymer (P1) comprises between 0 wt % and 50 wt % of a functional monomer.

15. The composition according to claim 14 , wherein the (meth) acrylic polymer (P1) comprises between 1 wt % and 30 wt % of a functional monomer.

16. The composition according to claim 14 , wherein the functional comonomer is selected from the group consisting of glycidyl (meth)acrylate, acrylic or methacrylic acid, the amides derived from acrylic or methacrylic acids, dimethylacrylamide, 2-methoxyethyl acrylate or methacrylate, 2-aminoethyl acrylates or methacrylates that are optionally quaternized, acrylate or methacrylate monomers comprising a phosphonate or phosphate group, alkyl imidazolidinone (meth) acrylates, polyethylene glycol (meth) acrylates.

17. A process for manufacturing a liquid composition according to claim 1 comprising the steps of

a) preparing a composition comprising a (meth) acrylic polymer (P1) and a multi stage polymer, and

b) mixing the composition of previous step a) with a (meth)acrylic monomer (M1)

wherein the multistage polymer to monomer ratio in the liquid composition is between 1/99 and 25/75.

18. The process according to claim 17 , wherein the (meth) acrylic polymer (P1) has a mass average molecular weight Mw of between 5,000 g/mol and 70,000 g/mol.

19. The process according to claim 17 , wherein the (meth) acrylic polymer (P1) has a mass average molecular weight Mw between 6,000 g/mol and 50,000 g/mol.

20. An impact modified polymer prepared from the composition according to claim 1 .