KIT COMPRISING SURFACE-TREATED CALCIUM CARBONATE AND A PEROXIDE AGENT FOR IMPROVING THE MECHANICAL PROPERTIES OF POLYETHYLENE/POLYPROPYLENE COMPOSITIONS

Abstract

The present invention relates to a kit of parts comprising a surface-treated calcium carbonate-containing filler material and a peroxide agent for improving the mechanical properties of a polymer mixture comprising at least one polyethylene polymer and at least one polypropylene polymer, a filled polymer mixture, a process for the preparation of a filled polymer composition, a filled polymer composition obtained thereby or obtainable by reacting the filled polymer mixture, the use of a surface-treated calcium carbonate-containing filler material and a peroxide reagent for reacting a polymer composition comprising at least one polyethylene polymer and at least one polypropylene polymer, preferably thereby improving the mechanical properties of the polymer composition, as well as an article comprising the filled polymer mixture or the filled polymer composition.

Claims

1-22. (canceled)

23. A kit of parts for improving the mechanical properties of a polymer mixture comprising at least one polyethylene polymer and at least one polypropylene polymer, the kit of parts comprising a) a surface-treated calcium carbonate-containing filler material, wherein the surface-treated calcium carbonate-containing filler material comprises a calcium carbonate-containing filler material having i) a weight median particle size (d.sub.50) value in the range from 0.03 .Math.m to 4.0 .Math.m and ii) a top cut (d.sub.98) value of 30 .Math.m or less, and a surface-treatment layer on at least a part of the surface of said calcium carbonate-containing filler material, wherein the surface-treatment layer comprises at least one mono- or di-substituted succinic anhydride comprising at least one unsaturated carbon moiety and/or a salt thereof and/or acid thereof and/or salty reaction products thereof, and b) a peroxide agent.

24. The kit of parts of claim 23, wherein the calcium carbonate-containing filler material has i) a weight median particle size (d.sub.50) value in the range from 0.05 .Math.m to 3 .Math.m, and/or ii) a top cut (d.sub.98) value of 20 .Math.m or less, and/or iii) a specific surface area (BET) from 0.5 to 120 m.sup.2/g, as measured by the BET method, and/or iv) a residual total moisture content of at most 0.3 wt.-%, based on the total dry weight of the calcium carbonate-containing filler material.

25. The kit of parts of claim 23, wherein the surface-treatment layer comprises I) at least one mono- or di-substituted succinic anhydride comprising at least one unsaturated carbon moiety and having a total amount of carbon atoms from C.sub.2 to C.sub.30 in the substituent and/or an acid and/or salt thereof, and/or II) a grafted polymer comprising at least one succinic anhydride group obtained by grafting maleic anhydride onto a homo- or copolymer comprising butadiene units and optionally styrene units, and/or III) salty reaction products of I) and/or II), and/or IV) mixtures of the compounds according to I) to III).

26. The kit of parts of claim 25, wherein the grafted polymer comprises at least one succinic anhydride group obtained by grafting maleic anhydride onto a homopolymer comprising butadiene units having i) a number average molecular weight M.sub.n measured by gel permeation chromatography from 1000 to 20000 g/mol, measured according to EN ISO 16014-1:2019, and/or ii) a number of anhydride groups per chain in the range from 2 to 12, and/or iii) an anhydride equivalent weight in the range from 400 to 2200 g/mol, and/or iv) an acid number in the range from 10 to 300 meq KOH per g of grafted polymer, measured according to ASTM D974-14, and/or v) a molar amount of 1,2-vinyl groups in the range from 5 to 80 mol-%, based on the total amount of unsaturated carbon moieties in the grafted polymer, and/or an acid or salt thereof.

27. The kit of parts of claim 23, wherein the surface-treatment layer comprises at least one mono- or di-substituted succinic anhydride comprising at least one unsaturated carbon moiety having a total amount of carbon atoms from C.sub.2 to C.sub.30 in the substituent and/or an acid or salt thereof and/or salty reaction products thereof, and wherein the at least one mono- or di-substituted succinic anhydride does not comprise a terminal double bond.

28. The kit of parts of claim 23, wherein the surface-treatment layer further comprises at least one saturated surface-treatment agent selected from the group consisting of I) a phosphoric acid ester blend of one or more phosphoric acid mono-ester and/or salts thereof and/or one or more phosphoric acid di-ester and/or salts thereof, and/or II) at least one saturated aliphatic linear or branched carboxylic acid and/or salts thereof, and/or III) at least one mono-substituted succinic anhydride consisting of succinic anhydride mono-substituted with a group selected from a linear, branched, aliphatic and cyclic group having a total amount of carbon atoms from C.sub.2 to C.sub.30 in the substituent and/or salts thereof, and/or IV) at least one polydialkylsiloxane, polydimethylsiloxane, dimethicone, polydiethylsiloxane, polymethylphenylsiloxane and mixtures thereof, and/or V) at least one trialkoxysilane, and/or VI) mixtures of the materials according to I) to V).

29. The kit of parts of claim 23, wherein the surface-treated calcium carbonate-containing filler material has i) a hydrophilicity in the range from 0.01 to 4, indicated as the volumetric ratio of water: ethanol, measured at +23° C. (± 2° C.) with the sedimentation method, and/or ii) a moisture pick up susceptibility from 0.01 to 3 mg/g.

30. The kit of parts of claim 23, wherein the surface-treated calcium carbonate-containing filler material is comprised in a treated masterbatch in an amount from 50 to 85 wt.-%, based on the total amount of the treated masterbatch, wherein the treated masterbatch comprises at least one polyethylene polymer and/or at least one polypropylene polymer, and wherein the peroxide agent is present on the surface of the treated masterbatch.

31. The kit of parts of claim 23, wherein the surface-treatment layer comprises the peroxide agent, wherein the peroxide agent is present on the calcium carbonate-containing filler material in an amount from 0.01 to 0.5 wt.-%, based on the total amount of the surface-treated calcium carbonate-containing filler material.

32. A surface-treated calcium carbonate-containing filler material, wherein the surface-treated calcium carbonate-containing filler material comprises a calcium carbonate-containing filler material having i) a weight median particle size (d.sub.50) value in the range from 0.03 .Math.m to 4.0 .Math.m and ii) a top cut (d.sub.98) value of 30 .Math.m or less, and a surface-treatment layer on at least a part of the surface of said calcium carbonate-containing filler material, wherein the surface-treatment layer comprises a) at least one mono- or di-substituted succinic anhydride comprising at least one unsaturated carbon moiety and/or a salt thereof and/or acid thereof and/or salty reaction products thereof, and b) a peroxide agent.

33. The surface-treated calcium carbonate-containing filler material of claim 32, wherein peroxide agent is an organic peroxide agent.

34. A filled polymer mixture comprising a) the surface-treated calcium carbonate-containing filler material and the peroxide agent as defined in claim 23, b) at least one polyethylene polymer, and c) at least one polypropylene polymer, wherein the mixture comprises the surface-treated calcium carbonate-containing filler material in an amount from 2 wt.-% to 85 wt.-%, based on the total weight of the mixture.

35. The filled polymer mixture of claim 38, wherein a) the at least one polypropylene polymer is present in an amount from 1 to 99 wt.-%, based on the total weight of the polymer in the filled polymer composition, and/or b) the surface-treated calcium carbonate-containing filler material is present in an amount from 2 wt.-% to 70 wt.-%, based on the total weight of the filled polymer mixture.

36. A process for the production of a filled polymer composition, comprising the steps of a) providing a surface-treated calcium carbonate-containing filler material and a peroxide agent as defined in claim 23, b) providing at least one polyethylene polymer and at least one polypropylene polymer and/or a polymer mixture comprising polyethylene and polypropylene, c) mixing, in any order, the surface-treated calcium carbonate-containing filler material and the peroxide agent of step a), the polyethylene polymer and the polypropylene polymer and/or the polymer mixture of step b) to obtain a mixture, and d) compounding the mixture of step c) at a temperature of at least 170° C. to obtain a filled polymer composition, wherein the filled polymer composition comprises the surface-treated calcium carbonate-containing filler material in an amount from 2 wt.-% to 85 wt.-%, based on the total weight of the filled polymer composition.

37. A process for the production of a filled polymer composition, comprising the steps of a) providing a surface-treated calcium carbonate-containing filler material and a peroxide agent as defined in claim 23, b) providing at least one polyethylene polymer and at least one polypropylene polymer and/or a polymer mixture comprising polyethylene and polypropylene, c) mixing, in any order, the surface-treated calcium carbonate-containing filler material and the peroxide agent of step a), the polyethylene polymer and the polypropylene polymer and/or the polymer mixture of step b) to obtain a mixture, and d) compounding the mixture of step c) at a temperature of at least 170° C. to obtain a filled polymer composition, wherein the filled polymer composition comprises the surface-treated calcium carbonate-containing filler material in an amount from 2 wt.-% to 85 wt.-%, based on the total weight of the filled polymer composition, wherein in step a), providing the surface-treated calcium carbonate-containing filler material comprises the sub-steps of a1) providing a calcium carbonate-containing filler material as defined in claim 23, a2) providing a mono- or di-substituted succinic anhydride comprising at least one unsaturated carbon moiety and/or a salt thereof and/or acid thereof as defined in claim 23, a3) optionally providing at least one saturated surface-treatment agent and/or the peroxide agent, a4) heating the mono- or di-substituted succinic anhydride comprising at least one unsaturated carbon moiety and/or a salt thereof and/or acid thereof of step a2) to a temperature in the range from the melting point of the mono- or di-substituted succinic anhydride to less than 200° C., to obtain a molten mono- or di-substituted succinic anhydride and/or a salt thereof and/or acid thereof, and a5) contacting, in any order, the calcium carbonate-containing filler material of step a1), the molten mono- or di-substituted succinic anhydride and/or a salt thereof and/or acid thereof of step a4) and optionally the at least one saturated surface-treatment agent and/or the peroxide agent of step a3) to obtain a surface-treated calcium carbonate-containing filler material, and wherein the at least one saturated surface-treatment agent of step a3) is selected from the group consisting of I) a phosphoric acid ester blend of one or more phosphoric acid mono-ester and/or salts thereof and/or one or more phosphoric acid di-ester and/or salts thereof, and/or II) at least one saturated aliphatic linear or branched carboxylic acid and/or salts thereof, and/or III) at least one mono-substituted succinic anhydride consisting of succinic anhydride mono-substituted with a group selected from a linear, branched, aliphatic and cyclic group having a total amount of carbon atoms from C.sub.2 to C.sub.30 in the substituent and/or salts thereof, and/or IV) at least one polydialkylsiloxane, polydimethylsiloxane, dimethicone, polydiethylsiloxane, polymethylphenylsiloxane and mixtures thereof, and/or V) at least one trialkoxysilane, and/or VI) mixtures of the materials according to I) to V).

38. The process of claim 36, wherein mixing step c) comprises the sub-steps of c1) forming a masterbatch of the surface-treated calcium carbonate-containing filler material of step a) and at least one polyethylene polymer and/or at least one polypropylene polymer provided in step b), wherein the masterbatch comprises the surface-treated calcium carbonate-containing filler material in an amount from 50 to 85 wt.-%, based on the total amount of the masterbatch, c2) treating the masterbatch of step c1) with the peroxide agent of step a), to obtain a treated masterbatch, and c3) mixing the treated masterbatch obtained in step c2) with the same or different at least one polyethylene polymer and/or at least one polypropylene polymer and/or polymer mixture comprising polyethylene and polypropylene of step b) to obtain a mixture comprising polyethylene and polypropylene.

39. The process of claim 36, wherein mixing step c) comprises the sub-steps of c4) treating the surface-treated calcium carbonate-containing filler material with the peroxide agent of step a), to obtain a peroxide-comprising surface-treated calcium carbonate-containing filler material, and c5) mixing the peroxide-comprising surface-treated calcium carbonate-containing filler material obtained in step c4) and the at least one polyethylene polymer and/or the at least one polypropylene polymer and/or the polymer mixture comprising polyethylene and polypropylene of step b) to obtain a mixture.

40. The process of any one of claim 36, further comprising the step of e) forming the filled polymer composition obtained in step d) into an article.

41. A filled polymer composition obtainable by the process according to claim 36.

42. The filled polymer composition according to claim 41, wherein the impact strength of the polymer composition is increased, compared to the same polymer composition not comprising the peroxide agent or compared to the same polymer composition comprising the same calcium carbonate-containing filler material lacking a surface-treatment layer or compared to the same polymer composition not comprising the surface-treated calcium carbonate-containing filler material.

43. An article comprising the filled polymer composition obtainable by the process according to claim 36.

Description

THE INVENTIVE PROCESS FOR PRODUCING A FILLED POLYMER COMPOSITION

[0450] In a third aspect of the present invention, a process for the production of a filled polymer composition is provided. The process comprises the steps of [0451] a) providing a surface-treated calcium carbonate-containing filler material and a peroxide agent, wherein the surface-treated calcium carbonate-containing filler material comprises a calcium carbonate-containing filler material havingand a surface-treatment layer on at least a part of the surface of said calcium carbonate-containing filler material, wherein the surface-treatment layer comprises at least one mono- or di-substituted succinic anhydride comprising at least one unsaturated carbon moiety and/or a salt thereof and/or acid thereof and/or salty reaction products thereof, [0452] i) a weight median particle size (d.sub.50) value in the range from 0.03 .Math.m to 4.0 .Math.m and [0453] ii) a top cut (d.sub.98) value of 30 .Math.m or less, [0454] b) providing at least one polyethylene polymer and at least one polypropylene polymer and/or a polymer mixture comprising polyethylene and polypropylene, [0455] c) mixing, in any order, the surface-treated calcium carbonate-containing filler material and the peroxide agent of step a), the polyethylene polymer and the polypropylene polymer and/or the polymer mixture of step b) to obtain a mixture, and [0456] d) compounding the mixture of step c) at a temperature of at least 170° C. to obtain a filled polymer composition, wherein the filled polymer composition comprises the surface-treated calcium carbonate-containing filler material in an amount from 2 wt.-% to 85 wt.-%, based on the total weight of the filled polymer composition.

Step A)

[0457] According to step a) of the inventive process, a surface-treated calcium carbonate-containing filler material and a peroxide agent are provided. The surface-treated calcium carbonate-containing filler material comprises a calcium carbonate-containing filler material having [0458] i) a weight median particle size (d.sub.50) value in the range from 0.03 .Math.m to 4.0 .Math.m and [0459] ii) a top cut (d.sub.98) value of 30 .Math.m or less,and a surface-treatment layer on at least a part of the surface of said calcium carbonate-containing filler material, wherein the surface-treatment layer comprises at least one mono- or di-substituted succinic anhydride comprising at least one unsaturated carbon moiety and/or a salt thereof and/or acid thereof and/or salty reaction products thereof.

[0460] It is appreciated that the surface-treated calcium carbonate-containing filler material, the calcium carbonate-containing filler material, the at least one surface-treatment agent and/or salty reaction products thereof and the peroxide agent are defined hereinabove.

[0461] In a preferred embodiment of the present invention, step a) of providing the surface-treated calcium carbonate-containing filler material comprises the sub-steps of [0462] a1) providing the calcium carbonate-containing filler material, [0463] a2) providing the at least one mono- or di-substituted succinic anhydride comprising at least one unsaturated carbon moiety and/or a salt thereof and/or acid thereof, [0464] a3) optionally providing at least one saturated surface-treatment agent as defined hereinabove and/or the peroxide agent, [0465] a4) heating the mono- or di-substituted succinic anhydride and/or a salt thereof and/or acid thereof of step a2) to a temperature in the range from the melting point of the at least one surface-treatment agent to less than 200° C., preferably less than 120° C., to obtain a molten mono- or di-substituted succinic anhydride and/or a salt thereof and/or acid thereof, [0466] a5) contacting, in any order, the calcium carbonate-containing filler material of step a1), and the molten mono- or di-substituted succinic anhydride and/or a salt thereof and/or acid thereof of step a4) and optionally the at least one saturated surface-treatment agent and/or the peroxide reagent of step a3) to obtain a surface-treated calcium carbonate-containing filler material,preferably wherein steps a1) to a5) are performed in absence of a solvent.

[0467] It is preferred that in step a1) the calcium carbonate-containing filler material is provided in dry form. Heating step a4) may be performed by any means known to the skilled person. The optionally present at least one saturated surface-treatment agent as defined hereinabove and/or the peroxide agent of step a3) may also be heated prior to contacting step a5). It should be noted that the at least one saturated surface-treatment agent may be heated to a temperature in the range from the melting point of the at least one saturated surface-treatment agent to less than 200° C., preferably less than 120° C., for example, by admixing the saturated surface-treatment agent with the mono- or di-substituted succinic anhydride and/or a salt thereof and/or acid thereof prior to step a4). If a peroxide agent is provided, it is appreciated that said peroxide agent throughout process steps a3) to a5) is at most heated to a temperature slightly below the decomposition temperature of the peroxide agent, e.g., 90° C., preferably 70° C. While the peroxide agent may be admixed with the saturated surface-treatment agent and the mono- or di-substituted succinic anhydride and/or a salt thereof and/or acid thereof prior to step a4), provided that heating step a4) is performed at most at a temperature slightly below the decomposition temperature of the peroxide agent, e.g., 90° C., preferably 70° C., it is preferred that the peroxide agent is added separately during step a5), for example, after the molten mono- or di-substituted succinic anhydride and/or a salt thereof and/or acid thereof of step a4) and optionally the at least one saturated surface-treatment agent of step a3) have been contacted with the calcium carbonate-containing filler material and the temperature is reduced to a temperature of at most slightly below the decomposition temperature of the peroxide agent, e.g., 90° C., preferably 70° C.

[0468] It is preferred that steps a4) and a5) are carried out simultaneously, preferably in the same vessel. In said embodiment, heating step a4) may be performed by adding the mono- or di-substituted succinic anhydride and/or a salt thereof and/or acid thereof of step a2) to the calcium carbonate-containing filler material of step a1), which has been pre-heated to a temperature in the range from the melting point of the at least one surface-treatment agent to less than 200° C., preferably less than 120° C. In this embodiment, the optionally present at least one saturated surface-treatment agent of step a3) is also heated to a temperature in the range from the melting point of the at least one surface-treatment agent to less than 200° C., preferably less than 120° C., by contacting with the pre-heated calcium carbonate-containing filler material. The optionally present peroxide agent may be added to the pre-heated calcium carbonate-containing filler material, provided that its temperature does not exceed the decomposition temperature of the peroxide agent, e.g., 90° C., preferably 70° C. Step a5) is carried out under mixing. It is appreciated that the mixing can be carried out by any method or in any vessel known to the skilled person resulting in a homogeneous composition. For example, step a5) is carried out in a high speed mixer or pin mill.

[0469] Alternatively, the surface-treated calcium carbonate-containing filler material is obtained in a wet surface-treatment step. Suitable wet surface-treatment processes are known to the skilled person, and taught, e.g., in EP3192837 A1.

Step B)

[0470] According to step b) of the inventive process, at least one polyethylene polymer and at least one polypropylene polymer and/or a polymer mixture comprising polyethylene and polypropylene is provided. It is appreciated that the at least one polyethylene polymer and the at least one polypropylene polymer are as defined hereinabove.

[0471] It is to be understood that the at least one polyethylene polymer and the at least one polypropylene polymer may be provided separately and/or in the form of a polymer mixture. Preferably, the at least one polyethylene polymer, the at least one polypropylene polymer and/or the polymer mixture are derived from waste polymers.

[0472] In a preferred embodiment of the present invention, in step b) a polymer mixture is provided, which is derived from waste polymers comprising polyethylene and polypropylene. The polymer mixture being “derived from” waste polymers is understood in that the polymer mixture is obtained by a purification process. In this embodiment, step b) of providing the polymer mixture may comprise at least one of, preferably at least two of the sub-steps of b1) pre-sorting the waste plastic, b2) grinding the waste plastic, b3) cleaning the waste plastic and b4) sorting the waste plastic, in any order, preferably in the order set out herein.

[0473] According to pre-sorting step b1), separate and discrete pieces of different polymeric materials may be identified, e.g., by Fourier-transform infrared spectroscopy (FTIR), near-infrared spectroscopy, optical color recognition, X-ray detection, laser sorting and/or electrostatic detection, and subsequently mechanically separated, e.g., by selective collection and/or automated or manual sorting.

[0474] According to grinding step b2), the size of the waste plastic is reduced in order to facilitate the subsequent separation, cleaning and re-processing steps. The grinding step may be performed inter alia by shredding, crushing or milling. Preferably, the average particle size of the ground waste plastic is in the range from 0.2 to 10 mm.

[0475] According to cleaning step b3), the waste plastic, which is optionally ground, may be washed with a liquid preferably selected from the group consisting of water, optionally comprising at least one detergent and/or a soap, and/or organic solvents, such as alcohols, ketones and aliphatic hydrocarbons. Preferably, the organic solvent does not dissolve the polymers within the waste plastic.

[0476] According to sorting step b4), the polymer mixture preferably undergoes a step selected from gravimetrical sorting and/or sorting by dissolution/reprecipitation.

[0477] Preferably, the process for providing the polymer mixture comprises the sub-step of b5) drying the polymer mixture obtained after one of, or more of steps b1) to b4). Drying may take place using any suitable drying equipment known to the skilled person.

[0478] It is to be stressed that the separation of polyethylene polymers and polypropylene polymers in such process may be incomplete, such that the polymer mixture indeed is a mixture of polyethylene and polypropylene. Furthermore, the polymer mixture may comprise further polymers, e.g., polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), but also degradable polyesters, such as polylactic acid (polylactide, PLA) and polyethylene-2,5-furandicarboxylate, polyvinyl chloride, polyvinylidene chloride (PVDC), polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), polybutadiene, polyacrylonitrile, polymethylmethacrylate, polyamides, polyurethanes, and mixtures thereof.

[0479] Preferably, process steps b1) to b5) are performed such that the polymer mixture comprises the further polymers in an amount of at most 5 wt.-%, preferably at most 2 wt.-%, based on the total amount of polymer in the filled polymer composition.

[0480] In a preferred embodiment of the inventive process, in step b) a polymer mixture comprising polyethylene and polypropylene is provided, wherein the polymer mixture is derived from waste polymers.

[0481] In another preferred embodiment of the inventive process, in step b) a polymer mixture comprising polyethylene and polypropylene is provided, wherein the polymer mixture is derived from waste polymers, and additionally at least one polyethylene polymer and/or at least one polypropylene polymer is provided, wherein the at least one polyethylene polymer and the at least one polypropylene polymer are derived from virgin polymers.

Steps C) and D)

[0482] According to step c) of the inventive process, the polyethylene polymer and the polypropylene polymer and/or the polymer mixture of step b), and the surface-treated calcium carbonate-containing filler material and the peroxide agent of step a) are mixed, in any order, to obtain a mixture.

[0483] Mixing step c) may be performed by any means known to the skilled person, including, but not limited to, blending, extruding, kneading, and high-speed mixing.

[0484] According to step d) of the inventive process, the mixture of step c) is compounded to obtain a filled polymer composition, wherein the filled polymer composition comprises the surface-treated calcium carbonate-containing filler material in an amount from 2 wt.-% to 85 wt.-%, based on the total weight of the filled polymer composition.

[0485] In a preferred embodiment of the present invention, mixing step c) and compounding step d) are performed simultaneously. Preferably, the surface-treated calcium carbonate-containing filler material of step c) is admixed after mixing the polyethylene polymer and the polypropylene polymer and/or the polymer mixture of step b), more preferably wherein the mixture of the polyethylene polymer and the polypropylene polymer and/or the polymer mixture of step b) is at least partially in the molten state. Thus, it is appreciated that the mixing step c) may take place during compounding step d).

[0486] Mixing step c) and/or compounding step d) may be done with a suitable extruder, preferably by a twin screw extruder (co- or counter-rotating) or by any other suitable continuous compounding equipment, e.g. a continuous co-kneader (Buss), a continuous mixer (Farrel Pomini), a ring extruder (Extricom) or the like. The continuous polymer mass from extrusion may be either pelletized by (hot cut) die face pelletizing with underwater pelletizing, eccentric pelletizing and water ring pelletizing or by (cold cut) strand pelletizing with underwater and conventional strand pelletizing to form the extruded polymer mass into pellets.

[0487] Optionally, mixing step c) and/or compounding step d) may also be performed with a discontinuous or batch process using an internal (batch) mixer, e.g. a Banburry mixer (HF Mixing Group) or a Brabender mixer (Brabender) or the like.

[0488] During mixing step c) and/or compounding step d), at least one further polymer may be added. The at least one further polymer may be selected from the group comprising polystyrene, polyesters, such as polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), but also degradable polyesters, such as polylactic acid (polylactide, PLA) and polyethylene-2,5-furandicarboxylate, polyvinyl chloride, polyvinylidene chloride (PVDC), polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), polybutadiene, polyacrylonitrile, polymethylmethacrylate, polyamides, polyurethanes, and mixtures thereof. Preferably, the at least one further polymer is selected from the group comprising polystyrene, polyesters, preferably polyethylene terephthalate, polylactic acid, polyhydroxybutyrate and polyethylene-2,5-furandicarboxylate, polyvinyl chloride, polybutadiene, polyacrylonitrile, polymethylmethacrylate, polyamides, polyurethanes, and mixtures thereof. The at least one further polymer may be added in an amount of at most 50 wt.-%, preferably at most 30 wt.-%, more preferably at most 15 wt.-%, and most preferably at most 5 wt.-%, based on the total amount of the polymer in the filled polymer composition.

[0489] Additionally or alternatively, during mixing step c) and/or compounding step d), at least one additive may be added. The additive is selected from the group consisting of further fillers, preferably selected from the group consisting of talc, mica, kaolin, bentonite or mixtures thereof, UV-absorbers, light stabilizers, processing stabilizers, antioxidants, heat stabilizers, nucleating agents, metal deactivators, impact modifiers, plasticizers, lubricants, rheology modifiers, processing aids, pigments, dyes, optical brighteners, antimicrobials, antistatic agents, slip agents, anti-block agents, coupling agents, dispersants, compatibilizers, oxygen scavengers, acid scavengers, markers, antifogging agents, surface modifiers, flame retardants, blowing agents, smoke suppressors, or mixtures of the foregoing additives. The at least one additive may be added in an amount of up to 30 wt.-%, preferably up to 5 wt.-%, more preferably up to 2 wt.-%, based on the total weight of the filled polymer composition. The total amount of additives added may be up to 35 wt.-%, preferably up to 5 wt.-%, more preferably up to 2 wt.-%, based on the total weight of the filled polymer composition.

[0490] According to one embodiment, a further filler is added. The further filler may be selected from the group comprising carbon black, silica, ground natural calcium carbonate, precipitated calcium carbonate, nanofillers, graphite, clay, talc, diatomaceous earth, barium sulfate, titanium dioxide, wollastonite, and mixtures thereof. Preferably, the further filler is selected from the group consisting of talc, mica, kaolin, bentonite or mixtures thereof. The further filler may added in an amount of at most 30 wt.-%, more preferably at most 15 wt.-%, and most preferably at most 5 wt.-%, based on the total amount of the filled polymer composition.

[0491] It is to be understood that the further filler can be distinguished from the surface-treated calcium carbonate-containing filler material, e.g., by its chemical composition and/or by its particle size. Thus, it is to be understood that, if the at least one further filler is selected from ground natural calcium carbonate or precipitated calcium carbonate, said further filler has a weight median particle size (d.sub.50) value of more than 4.0 .Math.m and a top cut (d.sub.98) value of more than 30 .Math.m and/or does not comprise a surface-treatment layer as defined hereinabove.

[0492] It is appreciated that in compounding step d), a filled polymer composition is obtained. The filled polymer composition comprises the surface-treated calcium carbonate-containing filler material in an amount from 2 wt.-% to 85 wt.-%, based on the total weight of the filled polymer composition. It is to be understood that the amounts of the at least one polyethylene polymer, the at least one polypropylene polymer and/or the polymer mixture comprising polyethylene and polypropylene, the surface-treated calcium carbonate-containing filler material and optionally the at least one further polymer and/or the at least one additive and/or the peroxide agent, if present, are provided and/or added during mixing step c) and/or compounding step d) such that the so-obtained filled polymer composition comprises the surface-treated calcium carbonate-containing filler material in the required amounts.

[0493] If in step b) a polymer mixture comprising polyethylene and polypropylene and being derived from waste polymers is provided, it is appreciated that said polymer mixture may comprise further polymers and further additives. Furthermore, if said polymer mixture is derived from waste polymers comprising the inventive filler, as would be the case, if the inventive filled polymer composition as described hereinabove were to be disposed of and would form part of said waste polymers, the polymer mixture provided in step b) already contains certain amounts of the inventive filler. Consequently, the amounts of polyethylene, polypropylene, further polymers, further additives and the surface-treated calcium carbonate-containing filler material, which may already be present in the polymer mixture have to be taken into account when performing the inventive process.

[0494] The skilled person knows how to determine the composition of the polymer mixture by routine methods, such as determination of the ash content, Fourier-transform infrared spectroscopy (FTIR), near-infrared spectroscopy, X-ray detection, laser sorting, nuclear magnetic resonance and/or electrostatic detection methods. If the polymer mixture is derived from post-industrial waste polymers, the composition may be well-known from the manufacturer of said post-industrial waste polymers.

[0495] Consequently, the inventive process is performed such that the filled polymer composition obtained in step d) comprises the surface-treated calcium carbonate-containing filler material in an amount from 2 wt.-% to 85 wt.-%, preferably from 2 wt.-% to 70 wt.-%, more preferably from 5 wt.-% to 60 wt.%, most preferably 7 wt.-% to 40 wt.-%, based on the total weight of the filled polymer composition. Preferably, the inventive process is performed such that the filled polymer composition obtained in step d) comprises the peroxide agent and/or reaction products thereof in an amount from 0.01 to 0.5 wt.-%, preferably from 0.02 to 0.3 wt.-%, more preferably from 0.03 to 0.2 wt.-%, and most preferably from 0.04 to 0.15 wt.-%, based on the total amount of the surface-treated calcium carbonate-containing filler material.

[0496] Additionally or alternatively, the filled polymer composition obtained in step d) comprises the at least one polypropylene polymer in an amount from 0.5 to 99 wt.-%, preferably from 1 to 70 wt.-%, more preferably from 1 wt.-% to 50 wt.-%, still more preferably from 1 to 30 wt.-%, even more preferably from 2 to 30 wt.-% and most preferably from 5 to 30 wt.-%, based on the total weight of the polymer in the filled polymer composition. Additionally or alternatively, the filled polymer composition obtained in step d) comprises the at least one polyethylene polymer in an amount from 1.0 to 99.5 wt.-%, preferably from 30 to 99 wt.-%, more preferably from 50 wt.-% to 99 wt.-%, still more preferably from 70 to 99 wt.-%, even more preferably from 70 to 98 wt.-% and most preferably from 70 to 95 wt.-%, based on the total weight of the polymer in the filled polymer composition.

[0497] Additionally or alternatively, the filled polymer composition obtained in step d) comprises a total amount of polymer being derived from waste polymers of at least 20 wt.-%, preferably at least 50 wt.-%, more preferably at least 70 wt.-%, still more preferably at least 85 wt.-%, and most preferably at least 95 wt.-%, based on the total amount of polymer in the filled polymer composition.

[0498] Additionally or alternatively, the filled polymer composition obtained in step d) comprises at least one further polymer in an amount of at most 50 wt.-%, preferably at most 30 wt.-%, more preferably at most 15 wt.-%, and most preferably at most 5 wt.-%, based on the total amount of the polymer in the filled polymer composition.

[0499] Additionally or alternatively, the filled polymer composition obtained in step d) comprises at least one additive in an amount of up to 30 wt.-%, preferably up to 5 wt.-%, more preferably up to 2 wt.-%, based on the total weight of the filled polymer composition. The total amount of additives may be up to 35 wt.-%, preferably up to 5 wt.-%, more preferably up to 2 wt.-%, based on the total weight of the filled polymer composition.

[0500] In a preferred embodiment of the process of the present invention, mixing step c) and compounding step d) are performed simultaneously, wherein the surface-treated calcium carbonate-containing filler material of step a) is admixed after mixing the polyethylene polymer and the polypropylene polymer and/or the polymer mixture of step b), more preferably wherein the mixture of the polyethylene polymer and the polypropylene polymer and/or the polymer mixture of step b) is at least partially in the molten state. For example, the inventive filler may be injected directly into the injection zone of the extruder, e.g., at any split-feed inlet port along the kneading screw of the extruder. A suitable process is disclosed in EP2981568 A1.

[0501] In another preferred embodiment of the process of the present invention, compounding step d) is performed at a temperature in the range from 150 to 260° C., more preferably from 170 to 240° C., and most preferably from 180 to 230° C., and/or compounding step d) is an extrusion step.

[0502] In a preferred embodiment of the present invention, the mixing step c) comprises the sub-steps of [0503] c1) forming a masterbatch of the surface-treated calcium carbonate-containing filler material provided in step a) and at least one polyethylene polymer or at least one polypropylene polymer provided in step b), wherein the masterbatch comprises the surface-treated calcium carbonate-containing filler material in an amount from 50 to 85 wt.-%, preferably 60 to 85 wt.-%, more preferably 65 to 80 wt.-%, based on the total amount of the masterbatch, [0504] c2) treating the masterbatch of step c1) with the peroxide agent of step a), wherein the peroxide agent preferably is present in treating step c2) in an amount from 0.01 to 0.5 wt.-%, preferably from 0.02 to 0.3 wt.-%, more preferably from 0.03 to 0.2 wt.-%, and most preferably from 0.04 to 0.15 wt.-%, based on the total amount of the surface-treated calcium carbonate-containing filler material to obtain a treated masterbatch, and [0505] c3) mixing the masterbatch obtained in step c2) with the same or different at least one polyethylene polymer and/or at least one polypropylene polymer and/or polymer mixture comprising polyethylene and polypropylene of step b) to obtain a mixture comprising polyethylene and polypropylene, preferably wherein mixing step c3) and compounding step d) are performed simultaneously.

[0506] It is to be understood that the at least one polyethylene polymer or the at least one polypropylene polymer of step c1) may be the same or different from the at least one polyethylene polymer or the at least one polypropylene polymer provided in step b). However, the at least one polyethylene polymer or the at least one polypropylene polymer of step c1) are as described hereinabove.

[0507] Preferably, the masterbatch obtained in step c1) comprises at least one polyethylene polymer or at least one polypropylene polymer being a virgin polymer. In this embodiment, it is preferred that the treated masterbatch obtained in step c2) is mixed in step c3) with a polymer mixture comprising polyethylene and polypropylene and being derived from waste polymers.

[0508] Step c1) may be performed by any compounding method known to the skilled person. Preferably, step c1) is performed by a kneading process, wherein a premix of the surface-treated calcium carbonate-containing filler material of step a) and at least one polyethylene polymer or at least one polypropylene polymer of step b) is continuously fed to an extruder, such as a single screw or twin screw extruder. The extruder is heated to a temperature sufficiently high to allow for efficient mixing of the surface-treated calcium carbonate-containing filler material and the at least one polyethylene polymer or the at least one polypropylene polymer. A suitable temperature range is 150 to 260° C.

[0509] Alternatively, the surface-treated calcium carbonate-containing filler material may be added during step c1) to the at least partially molten at least one polyethylene polymer or the at least one polypropylene polymer, e.g., at any split-feed inlet port along the kneading screw of the extruder.

[0510] During step c1), at least one further additive as described hereinabove may be added.

[0511] The masterbatch may be obtained as a material having a defined shape, such as pellets, spheres, pearls, beads, prills, flakes, chips or slugs, or a non-defined shape, such as, for example, crumbles. Alternatively, the polymer composition may be a mixture of both defined and non-defined shape materials. Preferably, a pelletizing step is performed after the kneading process to provide the masterbatch in the form of pellets.

[0512] In a further embodiment of the present invention, the masterbatch obtained in step c1) consists of the surface-treated calcium carbonate-containing filler material of step a) and the polypropylene polymer or the polyethylene polymer of step b).

[0513] It is appreciated that in treating step c2), the masterbatch material is mixed with the peroxide agent such that the peroxide agent is soaked onto the masterbatch material, i.e., is dispersed or dissolved on the surface of the masterbatch material. Preferably, step c2) is performed such that the shape of the masterbatch material is essentially retained, e.g., by using standard mixing equipment that does not impart high shear forces onto the material (as would be the case, e.g., when using high-shear mixers or ball mills).

[0514] In the case that the peroxide agent is solid at room temperature, it is preferred that treating step c2) is performed at a temperature in the range from the melting point of the peroxide agent to slightly below the decomposition temperature of the peroxide agent to prevent premature reaction of the peroxide agent with the components of the masterbatch. For the purposes of the present invention, the “decomposition temperature” refers to the temperature at which the peroxide agent begins to decompose thermally, e.g., by cleavage of the oxygen-oxygen single bond. The decomposition temperature may be determined by differential scanning calorimetry or thermogravimetrical analysis and may be defined therein as an onset temperature.

[0515] For example, the peroxide agent may be pre-heated to a desired temperature and added to the masterbatch material. Alternatively, the mixing equipment itself may be heated to the desired temperature. Preferably, treating step c2) is performed at a temperature in the range from 0° C. to 90° C., preferably 20° C. to 75° C., more preferably 25° C. to 70° C.

[0516] Alternatively, step c) may comprise the sub-step c1) of forming a masterbatch, but does not comprise sub-step c2) of treating the masterbatch. Thus, in mixing step c3), the masterbatch of step c1) and the peroxide agent of step a) may be mixed separately, in any order, with the the same or different at least one polyethylene polymer and/or at least one polypropylene polymer and/or polymer mixture comprising polyethylene and polypropylene of step a) to obtain a mixture comprising polyethylene and polypropylene.

[0517] In yet another embodiment of the present invention, mixing step c) comprises the sub-steps of [0518] c4) treating the surface-treated calcium carbonate-containing filler material with the peroxide agent of step a), preferably in an amount from 0.01 to 0.5 wt.-%, more preferably from 0.02 to 0.3 wt.-%, still more preferably from 0.03 to 0.2 wt.-%, and most preferably from 0.04 to 0.15 wt.-%, based on the total amount of the surface-treated calcium carbonate-containing filler material to obtain a peroxide-comprising surface-treated calcium carbonate-containing filler material, and [0519] c5) mixing the peroxide-comprising surface-treated calcium carbonate-containing filler material obtained in step c5) and the at least one polyethylene polymer and/or the at least one polypropylene polymer and/or the polymer mixture comprising polyethylene and polypropylene of step b) to obtain a mixture,preferably wherein mixing step c5) and compounding step d) are performed simultaneously), more preferably wherein the mixture of the polyethylene polymer and the polypropylene polymer and/or the polymer mixture of step b) is at least partially in the molten state.

[0520] In the case that the peroxide agent is solid at room temperature, it is preferred that treating step c4) is performed at a temperature in the range from the melting point of the peroxide agent to slightly below the decomposition temperature of the peroxide agent to prevent premature reaction of the peroxide agent with the components of the masterbatch.

[0521] For example, the peroxide agent may be pre-heated to a desired temperature and added to the masterbatch material. Alternatively, the mixing equipment itself may be heated to the desired temperature. Preferably, treating step c4) is performed at a temperature in the range from 0° C. to 90° C., preferably 20° C. to 75° C., more preferably 25° C. to 70° C.

[0522] In another embodiment of the present invention, the process comprises at least one further step e) of forming the filled polymer composition obtained in step d) into an article, preferably by injection moulding or film or sheet formation. Preferred film formation processes include blown film formation and cast film formation.

[0523] In an exemplary embodiment of the present invention, the process comprises the steps of [0524] a) providing a surface-treated calcium carbonate-containing filler material comprising, and preferably consisting of, the calcium carbonate-containing filler material, having a weight median particle size (d.sub.50) value in the range from 0.03 .Math.m to 4.0 .Math.m, preferably from 0.05 to 3 .Math.m, more preferably from 0.1 .Math.m to 2.5 .Math.m, and/or a top cut (d.sub.98) value of 30 .Math.m or less, preferably 20 .Math.m or less; and a treatment layer comprising at least one mono- or di-substituted succinic anhydride comprising at least one unsaturated carbon moiety and/or a salt thereof and/or acid thereof and/or salty reaction products thereof, preferably wherein the at least one mono- or di-substituted succinic anhydride does not comprise a terminal double bond, and a peroxide agent, preferably an organic peroxide agent, [0525] b) providing at least one polyethylene polymer and at least one polypropylene polymer and/or a polymer mixture comprising polyethylene and polypropylene, [0526] c) mixing, in any order, the polyethylene polymer and the polypropylene polymer and/or the polymer mixture of step b), and the surface-treated calcium carbonate-containing filler material of step a) to obtain a mixture, and [0527] d) compounding the mixture of step c) to obtain a filled polymer composition, wherein the filled polymer composition comprises the surface-treated calcium carbonate-containing filler material in an amount from 2 wt.-% to 85 wt.-%, based on the total weight of the filled polymer composition, preferably wherein the total amount of polymer being derived from waste polymers is at least 20 wt.-%, more preferably at least 50 wt.-%, even more preferably at least 70 wt.-%, still more preferably at least 85 wt.-%, and most preferably at least 95 wt.-%, based on the total amount of polymer in the filled polymer composition.

[0528] In another exemplary embodiment of the present invention, the process comprises the steps of [0529] a) providing a surface-treated calcium carbonate-containing filler material comprising, and preferably consisting of, the calcium carbonate-containing filler material, having a weight median particle size (d.sub.50) value in the range from 0.03 .Math.m to 4.0 .Math.m, preferably from 0.05 to 3 .Math.m, more preferably from 0.1 .Math.m to 2.5 .Math.m, and/or a top cut (d.sub.98) value of 30 .Math.m or less, preferably 20 .Math.m or less; and a treatment layer comprising at least one mono- or di-substituted succinic anhydride comprising at least one unsaturated carbon moiety and having a total amount of carbon atoms from C.sub.2 to C.sub.30, preferably from C.sub.4 to C.sub.24, and more preferably from C.sub.8 to C.sub.20 in the substituent and/or an acid or salt thereof and/or salty reaction products thereof or a grafted polymer comprising at least one succinic anhydride group obtained by grafting maleic anhydride onto a homo- or copolymer comprising butadiene units and optionally styrene units and/or an acid and/or salt thereof; and a peroxide agent, preferably an organic peroxide agent, [0530] b) providing at least one polyethylene polymer and at least one polypropylene polymer and/or a polymer mixture comprising polyethylene and polypropylene, [0531] c) mixing, in any order, the polyethylene polymer and the polypropylene polymer and/or the polymer mixture of step b), and the surface-treated calcium carbonate-containing filler material of step a) to obtain a mixture, and [0532] d) compounding the mixture of step c) to obtain a filled polymer composition, wherein the filled polymer composition comprises the surface-treated calcium carbonate-containing filler material in an amount from 2 wt.-% to 85 wt.-%, based on the total weight of the filled polymer composition, preferably wherein the total amount of polymer being derived from waste polymers is at least 20 wt.-%, more preferably at least 50 wt.-%, even more preferably at least 70 wt.-%, still more preferably at least 85 wt.-%, and most preferably at least 95 wt.-%, based on the total amount of polymer in the filled polymer composition.

[0533] In still another preferred embodiment of the present invention, the process comprises the steps of [0534] a) providing a surface-treated calcium carbonate-containing filler material comprising, and preferably consisting of, the calcium carbonate-containing filler material, having a weight median particle size (d.sub.50) value in the range from 0.03 .Math.m to 4.0 .Math.m, preferably from 0.05 to 3 .Math.m, more preferably from 0.1 .Math.m to 2.5 .Math.m, and/or a top cut (d.sub.98) value of 30 .Math.m or less, preferably 20 .Math.m or less; and a treatment layer comprising at least one mono- or di-substituted succinic anhydride comprising at least one unsaturated carbon moiety and/or a salt thereof and/or acid thereof and/or salty reaction products thereof, preferably wherein the at least one mono- or di-substituted succinic anhydride does not comprise a terminal double bond, and a peroxide agent, preferably an organic peroxide agent [0535] b) providing at least one polyethylene polymer and/or at least one polypropylene polymer and a polymer mixture comprising polyethylene and polypropylene, [0536] c1) forming a masterbatch of the surface-treated calcium carbonate-containing filler material provided in step a) and at least one polyethylene polymer or at least one polypropylene polymer provided in step b), wherein the masterbatch comprises the surface-treated calcium carbonate-containing filler material in an amount from 50 to 85 wt.-%, preferably 60 to 85 wt.-%, more preferably 65 to 80 wt.-%, based on the total amount of the masterbatch, and [0537] c2) treating the masterbatch of step c1) with the peroxide agent of step a), wherein the peroxide agent preferably is present in treating step c2) in an amount from 0.01 to 0.5 wt.-%, preferably from 0.02 to 0.3 wt.-%, more preferably from 0.03 to 0.2 wt.-%, and most preferably from 0.04 to 0.15 wt.-%, based on the total amount of the surface-treated calcium carbonate-containing filler material to obtain a treated masterbatch, [0538] c3) mixing the masterbatch obtained in step c1) with the same or different at least one polyethylene polymer and/or at least one polypropylene polymer and/or polymer mixture comprising polyethylene and polypropylene of step a) to obtain a mixture comprising polyethylene and polypropylene, [0539] d) compounding the mixture of step c3) to obtain a filled polymer composition, wherein the filled polymer composition comprises the surface-treated calcium carbonate-containing filler material in an amount from 2 wt.-% to 85 wt.-%, based on the total weight of the filled polymer composition, preferably wherein mixing step c3) and compounding step d) are performed simultaneously, and preferably wherein the total amount of polymer being derived from waste polymers is at least 20 wt.-%, more preferably at least 50 wt.-%, even more preferably at least 70 wt.-%, still more preferably at least 85 wt.-%, and most preferably at least 95 wt.-%, based on the total amount of polymer in the filled polymer composition.

The Inventive Polymer Composition

[0540] A third aspect of the present invention relates to a filled polymer composition obtainable by reacting the inventive filled polymer mixture or obtainable by the inventive process.

[0541] It is appreciated that the “filled polymer composition” relates to a reaction product, which may be obtained by reacting the filled polymer mixture, e.g., by heating it to a certain temperature, for example above the decomposition temperature of the peroxide agent or by a process as described hereinbelow. Thus, the filled polymer composition comprises reaction products of the peroxide agent with the surface-treatment layer of the surface-treated calcium carbonate-containing filler material and/or the polyethylene polymer and/or the polypropylene polymer. The inventive filled polymer mixture and the inventive process for obtaining the filled polymer composition has been described in detail hereinabove.

The Inventive Use

[0542] A fourth aspect of the present invention relates to the use of a surface-treated calcium carbonate-containing filler material and a peroxide reagent for reacting a polymer mixture comprising at least one polyethylene polymer and at least one polypropylene polymer, [0543] wherein the surface-treated calcium carbonate-containing filler material comprises a calcium carbonate-containing filler material having [0544] i) a weight median particle size (d.sub.50) value in the range from 0.03 .Math.m to 4.0 .Math.m and [0545] ii) a top cut (d.sub.98) value of 30 .Math.m or less, [0546] and a surface-treatment layer on at least a part of the surface of said calcium carbonate-containing filler material, wherein the surface-treatment layer comprises at least one mono- or di-substituted succinic anhydride comprising at least one unsaturated carbon moiety and/or a salt thereof and/or acid thereof and/or salty reaction products thereof, to obtain a filled polymer composition.

[0547] The present inventors realized that by reacting the polymer mixture comprising the at least one polyethylene polymer and the at least one polypropylene polymer by use of the surface-treated calcium carbonate-containing filler material and the peroxide reagent, the mechanical properties of the resulting polymer composition can be improved.

[0548] It is appreciated that the surface-treated calcium carbonate-containing filler material, the calcium carbonate-containing filler material, the at least one surface-treatment agent and/or salty reaction products thereof, the peroxide agent, the at least one polyethylene polymer and at least one polypropylene polymer are as defined hereinabove.

[0549] In a preferred embodiment of the present invention, the at least one polyethylene polymer and the at least one polypropylene polymer are at least partially derived from waste polymers. Thus, the filled polymer composition may comprise a mixture of virgin and recycled polymers.

[0550] More preferably, the total amount of polymer being derived from waste polymers in the filled polymer composition is at least 20 wt.-%, more preferably at least 50 wt.-%, even more preferably at least 70 wt.-%, still more preferably at least 85 wt.-%, and most preferably at least 95 wt.-%, based on the total amount of polymer in the filled polymer composition.

[0551] Furthermore, the filled polymer composition may comprise further polymers, e.g., polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), but also degradable polyesters, such as polylactic acid (polylactide, PLA) and polyethylene-2,5-furandicarboxylate, polyvinyl chloride, polyvinylidene chloride (PVDC), polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), polybutadiene, polyacrylonitrile, polymethylmethacrylate, polyamides, polyurethanes, and mixtures thereof.

[0552] In one embodiment of the present invention, the at least one polypropylene polymer is present in the filled polymer composition in an amount from 0.5 to 99 wt.-%, preferably from 1 to 70 wt.-%, more preferably from 1 wt.-% to 50 wt.-%, still more preferably from 1 to 30 wt.-%, even more preferably from 2 to 30 wt.-% and most preferably from 5 to 30 wt.-%, based on the total weight of the polymer in the filled polymer composition. Additionally or alternatively, the at least one polyethylene polymer is present in the inventive filled polymer composition in an amount from 1.0 to 99.5 wt.-%, preferably from 30 to 99 wt.-%, more preferably from 50 wt.-% to 99 wt.-%, still more preferably from 70 to 99 wt.-%, even more preferably from 70 to 98 wt.-% and most preferably from 70 to 95 wt.-%, based on the total weight of the polymer in the filled polymer composition. In the case that the at least one polyethylene polymer and the at least one polypropylene polymer are at least partially derived from waste polymers, it is to be understood that the amounts of the at least one polyethylene polymer and the at least one polypropylene polymer are determined at least partially by the source and/or composition of the waste polymer. In view thereof, it is appreciated that the invention is not limited to specific amounts of polyethylene polymer and polypropylene polymer.

[0553] As an illustrative example, the filled polymer composition may comprise a polymer mixture being derived from waste polymers, which comprises, e.g., from 50 to 99 wt.-%, preferably from 70 to 99 wt.-%, more preferably from 70 to 98 wt.-%, most preferably from 70 to 95 wt.-%, based on the total weight of the polymer mixture, of at least one polyethylene polymer and, e.g., from 1 to 50 wt.-%, preferably from 1 to 30 wt.-%, more preferably from 2 to 30 wt.-%, most preferably from 5 to 30 wt.-%, based on the total weight of the polymer mixture, of at least one polypropylene polymer. The polymer mixture being derived from waste polymers may be present in an amount of at least 20 wt.-%, preferably at least 50 wt.-%, more preferably at least 70 wt.-%, still more preferably at least 85 wt.-%, and most preferably at least 95 wt.-%, based on the total amount of polymer in the filled polymer composition. Additionally, the filled polymer composition may comprise at least one further polyethylene polymer being a virgin polymer and/or at least one further polypropylene polymer being a virgin polymer, e.g., such that the polymer mixture and the at least one further polyethylene polymer being a virgin polymer and/or at least one further polypropylene polymer being a virgin polymer add up to 100 wt.-%, based on the total amount of polymer in the filled polymer composition.

[0554] Thus, in a preferred embodiment of the present invention, the filled polymer composition comprises a total amount of polymer being derived from waste polymers of at least 20 wt.-%, preferably at least 50 wt.-%, more preferably at least 70 wt.-%, still more preferably at least 85 wt.-%, and most preferably at least 95 wt.-%, based on the total amount of polymer in the filled polymer composition.

[0555] Preferably, the filled polymer composition comprises the at least one polyethylene polymer and the at least one polypropylene polymer in a combined amount of at least 50 wt.-%, preferably at least 80 wt.-%, more preferably at least 95 wt.-%, and most preferably at least 98 wt.-%, based on the total weight of the polymer in the filled polymer composition.

[0556] Preferably, the mechanical properties of the so-obtained filled polymer composition are improved.

[0557] The expression “improving the mechanical properties” is to be understood in that at least one of the mechanical properties of the polymer composition, e.g., impact strength or resilience, tensile modulus or elongation at break, is improved, compared to either the same polymer composition not comprising the surface-treated calcium carbonate-containing filler material or to the same polymer composition comprising the same calcium carbonate-containing filler material lacking a surface-treatment layer or to the same polymer composition not comprising the peroxide agent or to the same polymer composition comprising neither the surface-treated calcium carbonate-containing filler material nor the peroxide agent. By “the same polymer composition”, it is meant that a polymer composition not comprising the surface-treated calcium carbonate-containing filler material, or comprising the same calcium carbonate-containing filler material lacking a surface-treatment layer or not comprising the peroxide agent, all else being equal, is produced in the same way as the inventive polymer composition, i.e., following the same method steps for its production and using the same remaining compounds in the same relative amounts other than the omitted material (the surface-treated calcium carbonate-containing filler material or the surface-treatment layer or the peroxide agent, respectively).

[0558] Preferably, the tensile modulus of the polymer composition is essentially maintained or increased, preferably by at least 5%, more preferably at least 10%, and most preferably at least 15%, compared to the same polymer composition not comprising the surface-treated calcium carbonate-containing filler material. The tensile modulus is measured according to ISO 527-1:2019.

[0559] Preferably, the tensile modulus of the polymer composition is essentially maintained or increased, preferably by at least 5%, more preferably at least 10%, and most preferably at least 15%, compared to the same polymer composition comprising the same calcium carbonate-containing filler material lacking a surface-treatment layer. The tensile modulus is measured according to ISO 527-1:2019.

[0560] Preferably, the tensile modulus of the polymer composition is essentially maintained or increased, preferably by at least 5%, more preferably at least 10%, and most preferably at least 15%, compared to the same polymer composition comprising the same surface-treated calcium carbonate-containing filler material but lacking the peroxide agent. The tensile modulus is measured according to ISO 527-1:2019.

[0561] Preferably, the tensile modulus of the polymer composition is essentially maintained or increased, preferably by at least 5%, more preferably at least 10%, and most preferably at least 15%, compared to the same polymer composition comprising neither the surface-treated calcium carbonate-containing filler material nor the peroxide agent.

[0562] In a preferred embodiment of the present invention, the impact strength or resilience of the polymer composition is increased, preferably by at least 10%, more preferably by at least 20%, even more preferably by at least 25%, or by at least 50%, for example at least 100%, determined by ISO 179-1eA:2010-11, compared to the same polymer composition not comprising the surface-treated calcium carbonate-containing filler material.

[0563] In a particularly preferred embodiment of the present invention, the impact strength or resilience of the polymer composition is increased, preferably by at least 10%, more preferably by at least 20%, even more preferably by at least 25%, or by at least 50%, for example at least 100%, determined by ISO 179-1eA:2010-11, compared to the same polymer composition comprising the same calcium carbonate-containing filler material lacking a surface-treatment layer.

[0564] In a preferred embodiment of the present invention, the impact strength or resilience of the polymer composition is increased, preferably by at least 10%, more preferably by at least 20%, even more preferably by at least 25%, or by at least 50%, for example at least 100%, determined by ISO 179-1eA:2010-11, compared to the same polymer composition comprising the same surface-treated calcium carbonate-containing filler material but lacking the peroxide agent.

[0565] Preferably, the impact strength or resilience of the polymer composition is increased, preferably by at least 10%, more preferably by at least 20%, even more preferably by at least 25%, or by at least 50%, for example at least 100%, determined by ISO 179-1eA:2010-11, compared to the same polymer composition comprising neither the surface-treated calcium carbonate-containing filler material nor the peroxide agent.

The Inventive Article

[0566] A fifth aspect of the present invention relates to an article comprising the inventive filled polymer mixture or the inventive filled polymer composition as defined hereinabove.

[0567] Preferably, the inventive article may comprise the inventive filled polymer composition inventive filled polymer mixture or the in the form of fibers, filaments, films, threads, sheets, pipes, profiles, molds, injection molded compounds and blow molded compounds.

[0568] The inventive article may be used in packaging applications, (in the form of plastic bags, films, containers, bottles, food packagings, microwavable containers, trays etc.), building and construction applications, automotive applications, electrical and electronic applications, agricultural applications, household applications and leisure and sports applications.

[0569] The article is preferably selected from the group comprising hygiene products, medical and healthcare products, filter products, geotextile products, agriculture and horticulture products, clothing, footwear and baggage products, household and industrial products, packaging products, construction products and the like. For example, the article may be selected from the group comprising pipes, paint pots, flower pots, garden chairs, bottles, plastic bags, films, containers, food packagings, microwavable containers, trays, automotive parts, bank notes, hinged caps, sweet and snack wrappers, agricultural film, toys, houseware, window frames, profiles, floor and wall covering, cable insulation, garden hoses, garbage bins and the like.

[0570] Preferably, the mechanical properties of the inventive article are improved as defined hereinabove.

[0571] Preferably, the impact strength or resilience of the article is increased, preferably by at least 10%, more preferably by at least 20%, even more preferably by at least 25%, or by at least 50%, for example at least 100%, determined by ISO 179-1eA:2010-11, compared to the same article not comprising the peroxide agent or compared to the same article comprising the same calcium carbonate-containing filler material lacking a surface-treatment layer.

[0572] The following examples are meant to additionally illustrate the invention. However, the examples are not meant to restrict the scope of the invention in any way.

EXAMPLES

I. Analytical Methods

BET Specific Surface Area of a Material

[0573] Throughout the present document, the specific surface area (in m.sup.2/g) of the mineral filler is determined using the BET method (using nitrogen as adsorbing gas), which is well known to the skilled man (ISO 9277:2010). The total surface area (in m.sup.2) of the mineral filler is then obtained by multiplication of the specific surface area and the mass (in g) of the mineral filler prior to treatment.

Amount of Surface-Treatment Layer

[0574] The amount of the treatment layer on the calcium carbonate-comprising filler material is calculated theoretically from the values of the BET of the untreated calcium carbonate-containing filler material and the amount of at least one hydrophobizing agent that are used for the surface-treatment.

Particle Size Distribution (Mass% Particles with a Diameter < X) and Weight Median Diameter (d.SUB.50.) of a Particulate Material

[0575] As used herein and as generally defined in the art, the “d.sub.50” value is determined based on measurements made by using a Sedigraph™ 5100 of Micromeritics Instrument Corporation and is defined as the size at which 50% (the median point) of the particle mass is accounted for by particles having a diameter equal to the specified value.

[0576] The method and the instrument are known to the skilled person and are commonly used to determine grain size of fillers and pigments. The measurement is carried out in an aqueous solution of 0.1 wt.-% Na.sub.4P.sub.2O.sub.7. The samples are dispersed using a high speed stirrer and supersonics.

Impact Properties

[0577] The impact properties are measured according to ISO 179-1eA:2010-11 on a HIT5.5P device from Zwick Roell. Measurements are performed on notched samples with a hammer of 2 J. All measurements are performed on samples that have been stored under similar conditions after preparation.

II. Experimental Part

Part 1: Surface-Treated Calcium Carbonate Preparation

[0578] Materials used in the examples:

[0579] 1. Polymer resin

[0580] Example 1: The polymer resins used are a virgin linear low density polyethylene (CAS No. 9002-88-4) Dowlex®2631.10UE (MFR = 7 g/10 min) commercially available from Resinex® and a virgin polypropylene PP (CAS No. 9003-07) Moplen™ HP525J (MFR = 3 g/10 min) from LyondellBasell®,

[0581] Example 2: The polymer resin used are a virgin linear low density polyethylene (CAS No. 9002-88-4) Dowlex2631.10UE (MFR = 7 g/10 min) commercially available from Resinex and a recycled polypropylene containing 20 wt.-% talc.

[0582] Example 3: The polymer resin used are KWR105M2 (MFR = 4 g/10 min), a mixture of high density polyethylene HDPE and 15% polypropylene derived from post-consumer waste polymer from KW Plastics as main matrix and a virgin linear low density polyethylene (CAS No. 9002-88-4) LLDPE 6101XR (MFR 20 g/10 min) commercially available from ExxonMobil® for masterbatches.

[0583] 2. Calcium carbonate-containing filler material CC1

[0584] The calcium carbonate CC1 is a dry ground marble from Italy (d.sub.50 = 1.7 .Math.m, d.sub.98 = 8 .Math.m (measured with Sedigraph), BET SSA = 4.1 m.sup.2/g).

[0585] 3. Hydrophobizing agent 01: ASA 1

[0586] Mono-substituted alkenyl succinic anhydride (2,5-Furandione, dihydro-, mono-C.sub.15-20-alkenyl derivs., CAS No. 68784-12-3) is a blend of mainly branched octadecenyl succinic anhydrides (CAS #28777-98-2) and mainly branched hexadecenyl succinic anhydrides (CAS #32072-96-1). More than 80% of the blend is branched octadecenyl succinic anhydrides. The purity of the blend is > 95 wt.-%. The residual olefin content is below 3 wt.-%.

[0587] 4. Hydrophobizing agent 02: Fatty acids mixture 2

[0588] Fatty acid mixture 2 is a mixture of about 40% stearic acid and about 60% palmitic acid.

[0589] 5. Hydrophobizing agent 03:

[0590] Hydrophobizing agent 03 is a grafted polybutadiene homopolymer comprising at least one succinic anhydride group obtained by grafting maleic anhydride onto a polybutadiene homopolymer (Mn = 3100 Da, Brookfield viscosity (25° C.) = 6500 cPs ± 3500, functional groups/chain = 2, anhydride equivalent weight 1238 g/mol; acid number: 40.1-51.5 meq KOH/g, total acid: 7-9 wt.-%, microstructure (molar% of butadiene): 20-35% 1-2 vinyl functional groups) commercially available from Cray Valley® under the trade name RICON® 130MA8.

[0591] 6. Cross-linking agent: DCP

[0592] Dicumyl peroxide (bis(1-methyl-1-phenylethyl) peroxide, CAS No. 80-43-3) is a radical initiator obtained from Sigma-Aldrich.

Surface Treatment Process

[0593] Surface treatments were carried in a high speed mixer (Somakon MP-LB Mixer, Somakon Verfahrenstechnik, Germany), and conditioned by stirring for 10 minutes at the treatment temperature (600-1000 rpm). After that time, the additives were added to the mixture and stirring and heating is then continued for another 15 minutes for each step (600-1000 rpm). After that time, the mixture is allowed to cool and the powder is collected.

TABLE-US-00001 Preparation of the surface treated calcium-carbonate filler material. Example Calcium carbonate (type and amount, kg) Additive 1 (parts by weight per hundred parts CaCO3) Additive 2 (parts by weight per hundred parts CaCO.sub.3) Additive 3 (parts by weight per hundred parts CaCO.sub.3) Treatment temperature CC2 CC1, 1 kg ASA 1 (0.8) / / 120° C. CC3 CC1, 1 kg ASA 1 (0.8) DCP (0.1) / 120° C. for ASA, then cool down to 70° C. for DCP CC4 CC1, 1 kg ASA 1 (0.8) DCP (0.3) / 120° C. for ASA, then cool down to 70° C. for DCP CC5 CC1, 1 kg Fatty acids mixture 2 (1.0) Ricon 130 MA8 (0.1) DCP (0.3) 120° C., then cool down to 70° C. for DCP

Part 2: Processing Parameters

Example 1: Samples Containing 30 Wt.-% Filler in a Polymer Matrix of 70 Wt.-% LLDPE/30 Wt.-% PP.

[0594] Compounds CP-1 to CP-7 were produced on a twin-screw extruder 25:1 from Three Tec (Extruder Type ZE12, die: 0.5 mm) with the following line settings: [0595] Extruder temperatures: 20° C. (feeding) — 190° C. / 210° C. / 210° C. / 190° C. [0596] Feeding speed: 12% [0597] Screw speed: 30 rpm [0598] Conveyor speed: 1 rpm [0599] Cut speed: 14 rpm

[0600] Besides the conveyor belt a water bath is used to cool down the strand before cutting it.

[0601] The polymer matrix used is a mixture of a linear low-density polyethylene (LLDPE) that can be obtained from Resinex under the tradename Dowlex2631.10UE and a virgin polypropylene from LyondellBasell under the tradename Moplen HP525J. The composition of the polymer matrix is a ratio of 70 wt.-%LLDPE — 30 wt.-% PP.

[0602] All polymeric components (granules) were grinded on a Retsch® SR300 rotor beater mill before use. All components of the compounds are premixed together in a vessel before being extruded.

TABLE-US-00002 preparation and composition of Compounds CP-1 to CP-7 Sample (comparative/ inventive) Polymer 1 (wt.-%) Polymer 2 (wt.-%) Filler material (wt.-%) Additional Additive (parts by weight per hundred parts CaCO3) CP-1 (reference) Dowlex 2631.10UE (100%) / / / CP-2 (reference) / Polypropylene Moplen HP 525J (100%) / / CP-3 (comparative) Dowlex 2631.10UE (70%) Polypropylene Moplen HP 525J (30%) / / CP-4 (comparative) Dowlex 2631.10UE (49%) Polypropylene Moplen HP 525J (21%) CC 1 (30%) / CP-5 (comparative) Dowlex 2631.10UE (49%) Polypropylene Moplen HP 525J (21%) CC 1 (30%) DCP (0.06) CP-6 (comparative) Dowlex 2631.10UE (49%) Polypropylene Moplen HP 525J (21%) CC 2 (30%) / CP-7 (inventive) Dowlex 2631.10UE (49%) Polypropylene Moplen HP 525J (21%) CC 2 (30%) DCP (0.06)

Example 2: Samples Containing 20% Filler in a Polymer Matrix of 70 Wt.-% LLDPE/30 Wt.-% Recycled PP

[0603] Compounds CP-8 to CP-16 were produced on a twin-screw extruder 25:1 from Three Tec (Extruder Type ZE12, die: 0.5 mm) with the following line settings: [0604] Extruder temperatures: 20° C. (feeding) — 200° C. / 220° C. / 220° C. / 200° C. [0605] Feeding speed: 13% [0606] Screw speed: 40 rpm [0607] Conveyor speed: 1 rpm [0608] Cut speed: 15 rpm

[0609] Besides the conveyor belt a water bath is used to cool down the strand before cutting it.

[0610] The polymer matrix used is a mixture of a virgin linear low-density polyethylene (LLDPE) that can be obtained from Resinex under the tradename Dowlex2631.10UE and a recycled polypropylene containing 20 wt.-% talc. The composition of the polymer matrix is a ratio of 70 wt.-%LLDPE — 30 wt.-% rPP.

[0611] Some masterbatches are used for compounds 15 and 16.

[0612] Masterbatches 1 and 2 were produced on a twin-screw extruder 25:1 from Three Tec (Extruder Type ZE12, die: 0.5 mm) with the following line settings:

[0613] Extruder temperatures: 20° C. (feeding) — 200° C. / 220° C. / 220° C. / 200° C. [0614] Feeding speed: 6.5% [0615] Screw speed: 50 rpm [0616] Conveyor speed: 1 rpm [0617] Cut speed: 10 rpm

[0618] All polymeric components (granules) were grinded on a Retsch SR300 rotor beater mill before use. All components of the compounds or masterbatches are premixed together in a vessel before being extruded.

TABLE-US-00003 preparation and composition of Masterbatches 1 and 2 Sample Polymer (wt.-%) Surface treated filler material (wt.-%) MB-1 Dowlex 2631.10UE (20%) CC2 (80%) MB-2 Dowlex 2631.10UE (40%) CC3 (60%)

TABLE-US-00004 preparation and composition of Compounds CP-8 to CP-16 Sample (comparative/ inventive) Polymer 1 (wt.-%) Polymer 2 (wt.-%) Filler material (wt.-%) Masterbatch material (wt.-%) Additional Additive (parts by weight per hundred parts CaCO3) CP-8 (reference) Dowlex 2631.10UE (100%) / / / / CP-9 (reference) / Recycled polypropylene (100%) / / / CP-10 (comparative) Dowlex 2631.10UE (70%) Recycled polypropylene (30%) / / / CP-11 (comparative) Dowlex 2631.10UE (56%) Recycled polypropylene (24%) CC 1 (20%) / / CP-12 (comparative) Dowlex 2631.10UE (56%) Recycled polypropylene (24%) CC 2 (20%) / / CP-13 (inventive) Dowlex 2631.10UE (56%) Recycled polypropylene (24%) CC 3 (20%) / / CP-14 (inventive) Dowlex 2631.10UE (56%) Recycled polypropylene (24%) CC 2 (20%) / DCP (0.1) CP-15 (inventive) Dowlex 2631.10UE (51%) Recycled polypropylene (24%) / MB-1 (25%) DCP (0.1)* CP-16 (inventive) Dowlex 2631.10UE (42.7%) Recycled polypropylene (24%) / MB-2 (33.3%) / *The peroxide agent is not present in the masterbatch, but coated onto its surface in a high speed mixer from Somakon stirred at 600 rpm for 15 minutes at 70° C.

Example 3

[0619] Samples containing 20 wt.-% filler in a polymer derived from post-consumer waste polymer. Filled polymer compositions CP-17 to CP-23 and masterbatches for CP-22 and CP-23 were produced on a twin-screw extruder from MARIS (Extruder Type TM 20HT (D=20 mm, L/D=48, D/d=1.55, 11 Nm/cc, 15 kW, die: 2 holes of 3 mm diameter) with the following line settings [0620] Extruder temperatures: 70° C. / 190° C. / 190° C. / 180° C. / 170° C. / 170° C. / 170° C. / 170° C./170° C./170° C./180° C./190° C./210° C. [0621] Screw speed: 400 rpm (max speed possible: 1500 rpm)

[0622] The polymer matrix used is a mixture of high-density polyethylene (HDPE) and 15% polypropylene (PP) that can be obtained from KW Plastics under the tradename KWR105M2

TABLE-US-00005 preparation and composition of Masterbatches 3 and 4 Sample Polymer (wt.-%) Surface treated filler material (wt.-%) Coating additive (parts by weight per hundred parts CaCO3) MB-3 LLDPE 6101XR (80%) CC2 (80%) / MB-4 LLDPE 6101XR (80%) CC2 (80%) DCP (0.3)* *The peroxide agent is not present in the masterbatch, but coated onto its surface in a high speed mixer from Somakon stirred at 600 rpm for 15 minutes at 70° C.

TABLE-US-00006 Preparation and composition of filled polymer compositions CP-17 to CP-22 Sample (comparative/inventive) Polymer (wt.-%) Filler material (wt.-%) Masterbatch (wt.-%) CP-17 (reference) KWR105M2 (100%) / / CP-18 (comparative) KWR105M2 (80%) CC 1 (20%) / CP-19 (comparative) KWR105M2 (80%) CC 2 (20%) / CP-20 (inventive) KWR105M2 (80%) CC 4 (20%) / CP-21 (inventive) KWR105M2 (80%) CC5 (20%) / CP-22 (comparative) KWR105M2 (75%) / MB-3 (25%) CP-23 (inventive) KWR105M2 (75%) / MB-4 (25%)

Part 3: Effect on Impact Properties

[0623] Charpy samples were made by using a Xplore IM12 injection moulder from Xplore Instruments B.V with pellets produced as described in Table 2 and 4 with the settings indicated in Table 7:

TABLE-US-00007 Xplore IM12 conditions Melt temperature 210° C. Mould temperature 45° C. Melting time 3 min Pressure 1 + time 7 bars 2 s Pressure 2 + time 7 to 8 bars 3 s Pressure 3 + time 8 bars 12 s

[0624] The dimension of the produced samples are the following ones: 80 mm x 10 mm x 4 mm. These samples have been notched by using an Automatic NotchVis Plus from CEAST®. The radius of the notch is 0.25 mm with a depth of 2 mm.

[0625] Impact tests are made according to ISO179-1eA (notched).

TABLE-US-00008 Impact properties according to ISO179-1eA — samples containing virgin polyethylene and polypropylene ((comp) means comparative example; (inv) means according to the invention)) CP-1 (reference) CP-2 (reference) CP-3 (comp) CP-4 (comp) CP-5 (comp) CP-6 (comp) CP-7 (inv) Resilience (kJ/m.sup.2.sub.) 44.1 2.3 7.1 2.8 3.8 7.4 25.4

[0626] As can be seen from table 8.1 the impact strength can be improved by a treatment comprising only a hydrophobizing agent (CP-6, comparative) when compared to a similar composition containing an untreated calcium carbonate (CP-4, comparative). By further addition of peroxide to the treated calcium carbonate (CP-7, inventive) the impact strength can be further improved which is not the case with an untreated calcium carbonate. Thus it is the combination of the hydrophobizing surface treatment agent and the peroxide that allows a more significant increase of impact strength.

TABLE-US-00009 Impact properties according to ISO179-1eA — samples containing virgin polyethylene and recycled polypropylene ((comp) means comparative example; (inv) means according to the invention)) CP-8 (reference) CP-9 (reference) CP-10 (comp) CP-11 (comp) CP-12 (comp) CP-13 (inv) CP-14 (inv) CP-15 (inv) CP-16 (inv) Resilience (kJ/m.sup.2.sub.) 57.5 4.4 8.2 5.7 16.1 29.0 26.8 32.4 18.9

[0627] As can be seen from table 8.2, this example confirms the impact strength / resilience can be improved by a treatment (CP-12) comprising only a hydrophobizing agent when compared to an untreated calcium carbonate (CP-11). By further addition of a peroxide (used as a co-treatment or as an additive, respectively CP-13 and CP-14) the impact strength can be further improved and even more by using a peroxide-coated masterbatch (CP-15). These further improvements are even more significant when the hydrophobizing agent is an unsaturated compound. Furthermore, adding the inventive calcium carbonate filler to a PE/PP mixture increases the impact strength compared to the unfilled PE/PP mixture.

TABLE-US-00010 Impact properties according to ISO179-1eA — samples containing polymer derived from post-consumer waste polymer ((comp) means comparative example; (inv) means according to the invention)) CP-17 (reference) CP-18 (comp) CP-19 (comp) CP-20 (inv) CP-21 (inv) CP-22 (comp) CP-23 (inv) Resilience (kJ/m.sup.2.sub.) 9.6 4.0 8.3 27.0 20.8 7.5 13.3

[0628] As can be seen from table 8.3, this example confirms the impact strength / resilience can be improved by a treatment (CP-19) comprising only a hydrophobizing agent when compared to an untreated calcium carbonate (CP-18). By further addition of a peroxide (used as a co-treatment, CP-20) the impact strength can be further improved. These further improvements are even more significant when the hydrophobizing agent is an unsaturated compound. The use of a peroxide-coated masterbatch (CP-23) also provides an impact strength improvement when compared to the use of a masterbatch without the coating of peroxide (CP-22). Furthermore, adding the inventive calcium carbonate filler to a PE/PP mixture increases the impact strength compared to the unfilled PE/PP mixture.