Methacrylic composition for obtaining a coating having a rough texture and a matt appearance

1. Methacrylic composition comprising (100-x-y) parts of at least one methacrylic polymer that is a homopolymer or copolymer of methyl methacrylate (MMA) having dispersed therein:

x parts of particles of a thermoplastic polymer A comprising MMA as the main monomer that is either crosslinked or that has a weight-average molecular weight M w >300,000 g/mol (relative to a PMMA standard), with a weight-average diameter (ASTM D1921)>100 μm, and <500 μm;

y parts of particles of a crosslinked thermoplastic polymer B comprising MMA as the main monomer, with a weight-average diameter (ASTM D1921) ranging from 15 to 70 μm;

such that x is in the range of 2 to 20 and y is in the range of 10 to 25.

2. Composition according to claim 1 , in which x+y<33.

3. Composition according to claim 1 , in which x is in the range of 3 to 10.

4. Composition according to claim 1 , in which y is in the range of 15 to 25.

5. Composition according to claim 1 , in which the arithmetic mean roughness Ra>8 μm.

6. Composition according to claim 1 , in which the gloss<10%, at an angle of 60°.

7. Composition according to claim 1 , in which the size distribution of the thermoplastic polymer A particles has a standard deviation of at most 40%.

8. Composition according to claim 1 , in which the thermoplastic polymer A comprises, by weight, more than 65% of MMA monomer units.

9. Composition according to claim 8 , in which the thermoplastic polymer A is a polymethyl methacrylate or a copolymer of MMA and at least one comonomer that is copolymerizable with MMA by radical processing.

10. Composition according to claim 1 , in which the size distribution of the thermoplastic polymer B particles has a standard deviation of at most 40%.

11. Composition according to claim 1 , in which the thermoplastic polymer B is a crosslinked polymer comprising, by weight, more than 65% MMA monomer units.

12. Composition according to claim 11 , in which the thermoplastic polymer B is a polymethyl methacrylate or a copolymer of MMA and at least one comonomer that is copolymerizable with MMA by radical processing.

13. Composition according to claim 11 , in which the thermoplastic polymer B comprises, by weight, from 15 to 35% of styrene monomer units and from 65 to 85% of MMA monomer units.

14. Multilayer structure comprising:

a layer (I) comprising the methacrylic composition according to claim 1 ; and

a layer (II) comprising at least one thermoplastic polymer,

and an optional interlayer placed between layers (I) and (II).

15. Structure according to claim 14 , in which the thermoplastic polymer is a saturated polyester, an acrylonitrile-butadiene-styrene terpolymer ABS, a styrene-acrylonitrile copolymer SAN, ASA (acrylonitrile-styrene-acrylate copolymer), a polystyrene, a polypropylene, a polyethylene, polycarbonate, a polyphenylene oxide PPO, a polysulphone, a vinyl chloride polymer such as PVC, chlorinated PVC (CPVC) or expanded PVC.

16. Structure according to claim 14 , wherein said structure comprises a solid extruded strip or hollow profile.

17. The structure according to claim 14 comprising panels, cladding, garden edging, windows or shutters.

18. Composition according to claim 1 , wherein said

particles of thermoplastic polymer A have a weight-average molecular weight M w >400,000 g/mol (relative to a PMMA standard), with a weight-average diameter (ASTM D1921)>250 μm and <500 μm.

19. Composition of claim 1 , wherein;

y is in the range of 17 to 23;

the gloss is <4% at an angle of 60°;

the thermoplastic polymer A comprises, by weight, more than 75% of MMA monomer units; and

thermoplastic polymer B comprises more than 75% of MMA monomer units.

20. The structure according to claim 14 , wherein said structure is formed in a coextrusion process.