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

1. A polymer composition suitable as epoxy adhesive composition comprising,

a) a first part composition (P1) comprising,

a1) an epoxy resin,

a2) a multistage polymer (MP1) having a core-shell structure,

a3) a polymer (C1) chosen from a (meth)acrylic polymer,

and

b) a second part composition (P2) comprising,

b1) a curing agent,

wherein polymer (C1) has a mass average molecular weight Mw between 100,000 g/mol and 1,000,000 g/mol, and wherein the ratio r of the polymer (C1) in a composition comprising only the multistage polymer (MP1) and the polymer (C1) is from 5 wt % to 24 wt %.

2. The composition according to claim 1 , wherein polymer (C1) has a mass average molecular weight Mw between 105,000 g/mol and 900,000 g/mol.

3. The composition according to claim 1 , wherein polymer (C1) has a mass average molecular weight Mw between 140,000 g/mol and 500,000 g/mol.

4. The composition according to claim 1 wherein the ratio r of the polymer (C1) in a composition comprising only the multistage polymer (MP1) and polymer (C1) is from 7 wt % to 24 wt %.

5. The composition according to claim 1 wherein the ratio r of the polymer (C1) in a composition comprising only the multistage polymer (MP1) and polymer (C1) is from 10 wt % to 24 wt %.

6. The polymer composition according to claim 1 wherein polymer (C1) comprises at least 80 wt % of monomers C1 to C4 alkyl methacrylate and/or C1 to C8 alkyl acrylate monomers.

7. The polymer composition according to claim 1 wherein polymer (C1) comprises a functional comonomer.

8. The polymer composition according to claim 7 wherein the functional comonomer is chosen from glycidyl (meth)acrylate, acrylic or methacrylic acid, the amides derived from these acids, dimethylacrylamide, 2-methoxyethyl acrylate or methacrylate, 2-aminoethyl acrylates or methacrylates are optionally quaternized, and polyethylene glycol (meth) acrylates.

9. The polymer composition according to claim 7 , wherein at least 80 wt % of acrylic or methacrylic comonomers of polymer (C1) are chosen from methyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, tert-butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and mixtures thereof.

10. A structural adhesive polymer composition comprising a composition according to claim 1 .

11. A method for manufacturing a polymer composition suitable as epoxy adhesive composition comprising the steps of:

(a) providing a first part composition (P1) comprising,

a1) an epoxy resin,

a2) a multistage polymer (MP1) having a core-shell structure,

a3) a polymer (C1) chosen from a (meth)acrylic polymer;

(b) providing a second part composition (P2) comprising,

b1) a curing agent,

(c) curing the mixture of (P1) and (P2),

wherein polymer (C1) has a mass average molecular weight Mw between 100,000 g/mol and 1,000,000 g/mol, and wherein the ratio r of the polymer (C1) in a composition comprising only the multistage polymer (MP1) and the polymer (C1) is from 5 wt % to 24 wt %.

12. The method according to claim 11 , wherein polymer (C1) has a mass average molecular weight Mw between 105,000 g/mol and 900,000 g/mol.

13. The method according to claim 11 , wherein polymer (C1) has a mass average molecular weight Mw between 140,000 g/mol and 500,000 g/mol.

14. The method according to claim 11 wherein multistage polymer (MP1) has a core-shell structure and a3) the polymer (C1) of the first part composition (P1) form together a polymer composition (PC1) are made by a method for manufacturing comprising the steps of:

a) polymerizing by emulsion polymerization of a monomer or monomer mixture (A m ) to obtain one layer in stage (A) comprising polymer (A1) having a glass transition temperature of less than 10° C. ,

b) polymerizing by emulsion polymerization of a monomer or monomer mixture (B m ) to obtain layer in stage (B) comprising a polymer (B1) having a glass transition temperature of at least 60° C.,

c) polymerizing by emulsion polymerization of a monomer or monomer mixture (C m ) to obtain a layer in stage (C) comprising a polymer (C1) having a glass transition temperature of at least 30° C.

15. The method according to claim 11 wherein multistage polymer (MP1) having a core-shell structure and a3) the polymer (C1) of the first part composition (P1) form together a polymer composition (PC1) are made by a method for manufacturing comprising the steps of:

a) mixing of the polymer (C1) and the multi stage polymer (MP1),

b) optionally recovering the obtained mixture of previous step in form of a polymer powder,

wherein the polymer (C1) and the multi stage polymer (MP1) in step a) are in form of a dispersion in aqueous phase.

16. The method according to claim 11 wherein the ratio r of the polymer (C1) in a composition comprising only the multistage polymer (MP1) and the polymer (C1) is from 10 wt % to 24 wt %.