Heat-sealing material for aluminum foils and polyethylene terephthalate foils against polypropyl, polyvinyl chloride, and polystyrol containers

1. A heat-sealable coating system, comprising:

a film-forming dispersion, comprising

a polymer A which is a polyester or a polyester mixture,

a polymer B which is a (meth)acrylate homo- and/or

copolymer, comprising a methacrylate and/or

an acrylate, and

a polymer AB which is a graft copolymer comprising a polymer A and a polymer B,

wherein

the amount of polymer A is from 5% by weight to 60% by weight,

the amount of polymer B is from 5% by weight to 70% by weight,

the amount of polymer AB is from 5% by weight to 60% by weight,

based on the total weight of the polymer A, B and AB, and

wherein the ratio by weight of the entirety of the polymer A, B and AB to the weight of a solvent or of a solvent mixture L is from 5:1 to 1:5.

2. The heat-sealable coating system according to claim 1 , wherein polymer A is a polyester whose preparation involves copolymerization of itaconic acid.

3. The heat-sealable coating system according to claim 2 , wherein polymer A is a polyester whose proportion of itaconic acid, based on the total amount of polycarboxylic acids used, is from 0.1 mol % to 20 mol %.

4. The heat-sealable coating system according to claim 3 , wherein polymer A is a polyester whose proportion of itaconic acid, based on the total amount of polycarboxylic acids used, is from 2 mol % to 8 mol %.

5. The heat-sealable coating system according to claim 2 , further comprising a polymer D which is a polyvinyl chloride

and/or

a polymer D A which is a polyamide.

6. The heat-sealable coating system according to claim 5 , wherein

the amount of polymer D is from 0.1% by weight to 10% by weight and

the amount of polymer D A is from 0.1% by weight to 10% by weight, based on the total weight of the polymer A, B, AB, D and D A , and

wherein the ratio by weight of the entirety of the polymer A, B, AB, D and D A to the weight of the solvent or of the solvent mixture L is from 5:1 to 1:5.

7. The heat-sealable coating system according to claim 2 , wherein simultaneous presence of a polymer A and of an initiator is involved in polymerization of a monomer which leads to polymer B.

8. The heat-sealable coating system according to claim 7 , wherein reaction of the initiator with a double bond of an itaconic acid repeat unit in the polymer A forms a reactive centre for free-radical polymerization of a (meth)acrylate, and wherein said reactive center reacts further to give said graft copolymer AB.

9. The heat-sealable coating system according to claim 2 , further comprising

a polymer C which is an olefin polymer or an olefin copolymer, and

a polymer CB which is a graft polymer comprising a polymer C and a polymer B.

10. The heat-sealable coating system according to claim 9 , wherein the amount of polymer C is from 5% by weight to 60% by weight and the amount of polymer CB is from 5% by weight to 60% by weight, based on the total weight of the polymer A, B, AB, C and BC, and

wherein the ratio by weight of the entirety of the polymer A, B, AB, C and BC to the weight of the solvent or of the solvent mixture L is from 5:1 to 1:5.

11. The heat-sealable coating system according to claim 2 , wherein the polymer AB is a graft copolymer having a polyester main chain and poly(meth)acrylate side chain.

12. The heat-sealable coating system according to claim 2 , wherein polymer B is grafted simultaneously onto polymer A and a polymer C in order to prepare graft copolymers AB and CB.

13. The heat-sealable coating system according to claim 2 , comprising

said polymer A,

said polymer B,

a polymer C which is an olefin polymer or an olefin copolymer,

said polymer AB,

a polymer CB which is a graft polymer comprising a polymer C and a polymer B, and

a polymer D and/or a polymer D A , and

wherein

the amount of polymer A is from 5% by weight to 60% by weight,

the amount of polymer B is from 5% by weight to 70% by weight,

the amount of polymer C is from 5% by weight to 60% by weight,

the amount of polymer AB is from 5% by weight to 60% by weight,

the amount of polymer CB is from 5% by weight to 60% by weight,

the amount of polymer D is from 0% by weight to 10% by weight,

the amount of polymer D A is from 0% by weight to 10% by weight,

based on the total weight of the polymer A, B, AB, C, CB, D and D A ,

and that the ratio by weight of the entirety of the polymer A, B, AB, C, CB, D and D A to the weight of the solvent or of the solvent mixture L is from 5:1 to 1:5.

14. The heat-sealable coating system according to claim 1 , further comprising

a polymer C which is an olefin polymer or an olefin copolymer, and

a polymer CB which is a graft polymer comprising a polymer C and a polymer B.

15. The heat-sealable coating system according to claim 14 , wherein

the amount of polymer C is from 5% by weight to 60% by weight and

the amount of polymer CB is from 5% by weight to 60% by weight, based on the total weight of the polymer A, B, AB, C and BC, and

wherein the ratio by weight of the entirety of the polymer A, B, AB, C and BC to the weight of the solvent or of the solvent mixture L is from 5:1 to 1:5.

16. The heat-sealable coating system according to claim 1 , comprising an auxiliary and/or an additive.

17. A process for the sealing of a heat-sealable substrate, comprising:

sealing said substrate with a coating system according to claim 1 .

18. The process according to claim 17 , comprising sealing polyester foil or PET-coated foil to polystyrene, polyester or polyvinyl chloride.

19. The process according to claim 17 , comprising sealing polyester foil or aluminium foil or aluminium- or a PET-coated foil to polystyrene, polyester or polyvinyl chloride,

wherein in said coating system, polymer A is a polyester whose preparation involves copolymerization of itaconic acid, and

wherein said coating system further comprises

a polymer D which is a polyvinyl chloride and/or

a polymer D A which is a polyamide.

20. The process according to claim 17 , comprising sealing polyester foil or aluminium foil or aluminium- or a PET-coated foil to polypropylene, polyethylene, polystyrene, polyester or polyvinyl chloride wherein said coating system comprises

said polymer A,

said polymer B,

a polymer C which is an olefin polymer or an olefin copolymer,

said polymer AB,

a polymer CB which is a graft polymer comprising polymer C and polymer B, and

a polymer D which is a polyvinyl chloride and/or

a polymer D A which is a polyamide, and

wherein

the amount of polymer A is from 5% by weight to 60% by weight,

the amount of polymer B is from 5% by weight to 70% by weight,

the amount of polymer C is from 5% by weight to 60% by weight,

the amount of polymer AB is from 5% by weight to 60% by weight,

the amount of polymer CB is from 5% by weight to 60% by weight,

the amount of polymer D is from 0% by weight to 10% by weight, and

the amount of polymer D A is from 0% by weight to 10% by weight,

based on the total weight of the polymer A, B, AB, C, CB, D and D A ,

and wherein the ratio by weight of the entirety of the polymer A, B, AB, C, CB, D and D A to the weight of the solvent or of the solvent mixture L is from 5:1 to 1:5.

21. A method for the heat sealing, comprising:

heat-sealing polyester foil or aluminium- or a PET-coated foil to polystyrene, polyester or polyvinyl chloride with the coating system according to claim 1 .

22. A method for the heat sealing, comprising:

heat-sealing polyester foil or aluminium- or a PET-coated foil to polystyrene, polyester or polyvinyl chloride with the coating system according to claim 1 , wherein

said polymer A is a polyester whose preparation involves copolymerization of itaconic acid, and

wherein said coating system further comprises

a polymer D which is a polyvinyl chloride and/or

a polymer D A which is a polyamide.

23. A method for the heat sealing, comprising:

heat-sealing polyester foil or aluminium- or a PET-coated foil to polypropylene, polyethylene, polystyrene, polyester or polyvinyl chloride with the coating system according to claim 1 which comprises

said polymer A,

said polymer B,

a polymer C which is an olefin polymer or an olefin copolymer,

said polymer AB,

a polymer CB which is a graft polymer comprising polymer C and polymer B, and

a polymer D which is a polyvinyl chloride and/or a polymer D A is present and is a polyamide, and

wherein

the amount of polymer A is from 5% by weight to 60% by weight,

the amount of polymer B is from 5% by weight to 70% by weight,

the amount of polymer C is from 5% by weight to 60% by weight,

the amount of polymer AB is from 5% by weight to 60% by weight,

the amount of polymer CB is from 5% by weight to 60% by weight,

the amount of polymer D is from 0% by weight to 10% by weight, and

the amount of polymer D A is from 0% by weight to 10% by weight,

based on the total weight of the polymer A, B, AB, C, CB, D and D A ,

and that the ratio by weight of the entirety of the polymer A, B, AB, C, CB, D and D A to the weight of the solvent or of the solvent mixture L is from 5:1 to 1:5.