Polymer composition, its process of preparation and its use

1. A dry polymer composition P1 comprising:

a) from 30 wt % to 60 wt % of an inorganic mineral compound (F),

b) from 2 wt % to 15 wt % of a (meth)acrylic copolymer (A1) or a mixture of (meth)acrylic copolymers comprising at least 50 wt % of polymeric units coming from methyl methacrylate and having a glass transition temperature Tg between 60° C. and 106° C.,

c) a polymeric impact modifier (IM1) or a mixture of polymeric impact modifiers, wherein said polymeric impact modifier (IM1) is a multistage polymer particle having a multilayer structure comprising at least one layer (IM1L1) comprising a polymer (L1) having a glass transition temperature between −100° C. and 0° C. and at least another layer (IM1L2) comprising a polymer (L2) having a glass transition temperature between 60° C. and 150° C.,

wherein the three components of a), b) and c) add up to 100 wt %,

wherein the weight ratio of layer (IM1L1)/layer (IM1L2) in the multistage polymer is at least 85/15; and

wherein said dry polymer composition P1 comprises less than 3% humidity.

2. The composition according to claim 1 , wherein the inorganic compound (F) consists of a mineral filler (F1) and a flow aid (F2), wherein the weight ratio (F1)/(F2) is at least 5/1.

3. The composition according to claim 1 —comprising

a) between 30 wt % and 60 wt % of an inorganic mineral compound (F),

b) between 2 wt % and 15 wt % a (meth)acrylic copolymer (A1) and

c) a polymeric impact modifier (IM1).

4. The composition according to claim 1 , wherein the composition is in form of a powder having volume median particle size D50 between 1 μm and 500 μm.

5. The composition according to claim 4 , wherein each powder particle comprises the compounds of a), b) and c).

6. The composition according to claim 1 , wherein the weight ratio of layer (IM1L1)/layer (IM1L2) in the multistage polymer is at least 87/13.

7. The composition according to claim 1 , wherein the weight ratio of layer (IM1L1)/layer (IM1L2) in the multistage polymer is in a range by weight between 86/14 and 97/3.

8. The composition according to claim 1 , wherein the polymer L1 presents more than 85 wt % of the polymeric impact modifier (IM1).

9. The composition according to claim 1 , wherein the polymer L1 presents more than 86 wt %.

10. The composition according to claim 1 , wherein the polymer (L1) having a glass transition temperature between −100° C. and 0° C. is a (meth) acrylic polymer comprising at least 50 wt % of monomers from alkyl acrylates.

11. The composition according to claim 1 wherein at least a part of the inorganic mineral filler (F) is a mineral filler chosen from the group consisting of calcium carbonate, calcinated clay, silica (fumed or precipitated), clay, Montmorillonite nano-clay, zeolite, perlite, and titanium dioxide.

12. The composition according to claim 1 wherein the inorganic mineral filler (F) or the mixture thereof is chosen from calcium carbonate.

13. The composition according to claim 1 wherein the (meth)acrylic copolymer (A1) is chosen from the group consisting of copolymer comprising at least 50 wt % of methyl methacrylate.

14. The composition according to claim 1 wherein the (meth)acrylic copolymer (A1) has a weight average molecular weight of at least 1,000,000 g/mol.

15. A process for preparing a dry polymeric composition P1 comprising

a) from 30 wt % to 60 wt % of an inorganic compound (F)

b) from 2 wt % to 15 wt % of a (meth)acrylic copolymer (A1) comprising at least 50 wt % of polymeric units coming from methyl methacrylate and having a glass transition temperature Tg between 60° C. and 106° C.,

c) a polymeric impact modifier (IM1), wherein said polymeric impact modifier (IM1) is a multistage polymer particle having a multilayer structure comprising at least one layer (IM1L1) comprising a polymer (L1) having a glass transition temperature between −100° C. and 0° C. and at least another layer (IM1L2) comprising a polymer (L2) having a glass transition temperature between 60° C. and 150° C., and wherein the weight ratio of layer (IM1L1)/layer (IM1L2) in the multistage polymer is at least 85/15,

wherein the three components a), b) and c) add up to 100 wt %, said process comprising the steps of:

blending the three components of a), b) and c), while the two components b) and c) and at least 83.33 wt % of compound a) are in form of a dispersion in aqueous phase during the blending step to obtain a blend, and

drying said blend until said dry polymeric composition P1 comprises less than 3% humidity.

16. The process for preparing a composition P1 according to claim 15 wherein said inorganic compound (F) consists of a mineral filler (F1) and a flow aid (F2), wherein the weight ratio (F1)/(F2) is at least 5/1.

17. The process according to claim 15 ,

wherein said process comprises the steps of:

i) blending the three components of a), b) and c), while the three components are in form of a dispersion in aqueous phase during the blending step,

ii) drying the blend obtained in step i).

18. The process for preparing a polymeric composition P2 comprising polymer composition P1 according to claim 1 ,

wherein the said polymeric composition P2 further comprises

d) a thermoplastic polymer TP1,

said process comprising the step of:

blending the compositions P1 and the thermoplastic polymer TP1.

19. An article comprising transformed polymer composition according to claim 16 , wherein the article is a profile, a pipe, a siding, a flooring film, sheet or foamed article.