Extruded matt foil with improved mechanical properties and a high weathering resistance

1. A coextruded multilayer foil, comprising:

at least a layer A, and

a layer B,

wherein

the layer A comprises, based on the total weight of the layer A:

from 40.0 to 97.0 wt. % of a fluoropolymer selected from polyvinylidene fluoride (PVDF), polyvinylfluoride (PVF), polytetrafluorethylene (PTFE), polyethylenetetrafluoroethylene (ETFE), fluorinated ethylene-propylene (FEP) or a mixture or copolymer thereof;

from 0.0 to 45.0 wt. % of a polyalkyl(meth)acrylate; and

from 3.0 to 30.0 wt. % of glass beads; and

the layer B comprises, based on the total weight of the layer B:

from 10.0 to 90.0 wt. % of a poly(methyl)methacrylate;

from 10.0 to 90.0 wt. % of one or several impact modifiers selected from particulate impact modifiers and thermoplastic impact modifiers;

from 0.0 to 40.0 wt. % of a fluoropolymer selected from polyvinylidene fluoride (PVDF), polyvinylfluoride (PVF), polytetrafluorethylene (PTFE), polyethylenetetrafluoroethylene (ETFE), fluorinated ethylene-propylene (FEP) or a mixture or copolymer thereof;

from 0.0 to 5.0 wt. % of one or several UV-absorbers;

from 0.0 to 5.0 wt. % of one or several UV-stabilizers; and from 0.0 to 20.0 wt. % of an adhesion-promoting copolymer comprising

(i) from 70.0 to 95.0 wt. % methyl methacrylate;

(ii) from 0.5 to 15.0 wt. % maleic anhydride; and

(iii) from 0.0 to 25.0 wt. % of other vinyl-copolymerizable monomers having no functional groups other than the vinyl function, based on the weight of the adhesion-promoting copolymer; and

wherein the cumulative content of the poly(methyl)methacrylate and of the one or several impact modifiers in the layer B is at least 50 wt. % based on the weight of the layer B.

2. The foil according to claim 1 , wherein the layer A comprises:

from 85.0 to 97.0 wt. % of the fluoropolymer;

0.0 wt. % of the polyalkyl(meth)acrylate; and

from 3.0 to 15.0 wt. % of glass beads, based on the total weight of the layer A.

3. The foil according to claim 1 , wherein the fluoropolymer is a predominantly amorphous polyvinylidene fluoride or a microcrystalline polyvinylidene fluoride.

4. The foil according to claim 1 , wherein the glass beads are spherical and have an average diameter from 2.0 μm to 30.0 μm.

5. The foil according to claim 1 , wherein the polyalkyl(meth)acrylate is polymethyl methacrylate having an average molar weight Mw of from 80 000 g/mol to 180 000 g/mol and is obtainable by polymerization of a composition whose polymerizable constituents comprise, based on the weight of the polymerisable composition:

(a) from 50.0 to 99.9 wt. % of methyl methacrylate,

(b) from 0.1 to 50.0 wt. % of an acrylic acid ester of a C1-C4 alcohol,

(c) from 0.0 to 10.0 wt. % of at least one further monomer copolymerizable with the monomers (a) and (b).

6. The foil according to claim 1 , wherein at least 20 wt. % of the glass beads, based on the weight of the employed glass beads, have a diameter which is higher than an average thickness of the layer A.

7. The foil according to claim 1 , wherein the layer B comprises:

from 0.5 to 4.0 wt. % of a benzotriazole type compound as a first UV absorber;

from 0.5 to 3.0 wt. % of a triazine type compound as a second UV absorber; and

from 0.2 to 2.0 wt. % of a HALS type compound as a UV stabilizer, based on the total weight of the layer B.

8. The foil according to claim 1 , the foil further comprising an adhesion-promoting layer C, wherein

the layer B is located between the layer A and the layer C, and

the layer C comprises an adhesion-promoting copolymer comprising:

(i) from 70.0 to 95.0 wt. % methyl methacrylate;

(ii) from 0.5 to 15.0 wt. % maleic anhydride; and

(iii) from 0.0 to 25.0 wt. % of other vinyl-copolymerizable monomers having no functional groups other than the vinyl function, based on the weight of the adhesion-promoting copolymer.

9. The foil according to claim 1 , wherein

the layer A has a thickness from 1.0 μm to 30.0 μm; and

the layer B has a thickness from 15.0 μm to 150.0 μm.

10. A process for the manufacturing of the foil according to claim 1 , wherein the process comprises:

moulding the foil in a foil-moulding process from a composition comprising:

from 40.0 to 97.0 wt. % of a fluoropolymer;

from 0.0 to 45.0 wt. % of a polyalkyl(meth)acrylate; and

from 3.0 to 30.0 wt. % of glass beads, based on the total weight of the composition.

11. A multi-layer article, comprising a substrate which is at least partially covered by the foil according to claim 1 , wherein

the layer A forms an outer surface of the multi-layer article;

the layer B is located between the layer A and the substrate; and

the layer C, if present, is located between the layer B and the substrate.

12. The multi-layer article according to claim 11 , wherein

the layer B is adjacent to the layer A, and

the layer C, if present, is adjacent to the layer B.

13. A process for manufacturing of the multi-layer article according to claim 11 , the process comprising:

coating the substrate with the foil according to claim 1 by co-extrusion, lamination or extrusion lamination.

14. The process according to claim 13 , wherein the multi-layer article is a high-pressure laminate and the step of coating the substrate with the foil according to claim 1 is carried out at a pressure of not lower than 1 MPa and a temperature of not lower than 120° C.

15. The foil according to claim 2 , wherein the fluoropolymer is of a molecular weight Mw from 50 000 to 300 000 g/mol, determined by GPC.

16. The foil according to claim 4 , wherein the glass beads have an average diameter from 5.0 μm to 20.0 μm.

17. The foil according to claim 6 , wherein at least 80 wt. % of the glass beads have a diameter which is higher than the average thickness of the layer A.

18. The process according to claim 10 , wherein the foil-moulding process is a chill-roll process.

19. The multi-layer article according to claim 11 , where the multi-layer article is a high-pressure laminate.