EP4698595A1 - Soft polypropylene composition containing a recycled material - Google Patents

Abstract

A polyolefin composition (I) comprising: (A) 65-95 wt.% of a polypropylene composition having MFR(A) of 0.2-1.2 g/10min comprising: - 15-40 wt.% of a polymer fraction (a) comprising a propylene, the polymer fraction (a) having solubility in xylene at 25°C ≤ 10.0 wt.%; and - 60-85 wt.% of a polymer fraction (b) comprising a copolymer of ethylene with a comonomer selected from propylene and/or a CH₂=CHR alpha-olefin, the copolymer containing ethylene in amount ≤ 40 wt.%, the polymer fraction (b) having solubility in xylene at 25°C ≥ 60 wt.%, and (B) 5-35 wt.% of a recycled ethylene polymer having density ≤ 0.93 g/cm³ and MFR(B) of 0.1-10.0 g/10min.

Description

TITLE

SOFT POLYPROPYLENE COMPOSITION CONTAINING A RECYCLED MATERIAL

FIELD OF THE INVENTION

[0001] The present disclosure relates to a polyolefin composition containing a recycled material, in particular a recycled material rich in low density polyethylene, the composition being suitable for use in producing soft extruded articles, like roofing sheets and geomembranes.

BACKGROUND OF THE INVENTION

[0002] Polypropylene compositions comprising a polypropylene matrix into which elastomeric particles of an ethylene/alpha-olefin copolymer are dispersed have a good thermoplastic behaviour in combination with excellent elastic properties. These compositions are also endowed with a favourable balance of further properties, like high softness, high stress resistance and good weldability, which renders them suitable for use in roofing applications.

[0003] W003/076509 discloses a polyolefin composition comprising: (A) 15-40 wt.% of a crystalline copolymer of propylene and (B) 60-85 wt.% of an elastomeric fraction comprising a copolymer of propylene with ethylene and a copolymer of ethylene with alpha-olefins. The compositions show high tenacity, flexural modulus below 130 MPa and Shore D hardness lower than 40.

[0004] W02009/077481 discloses a membrane comprising a base layer (A) and a top layer

(B). The base layer (A) is made of a heterophasic composition comprising: (a) 10-40 wt.% of a propylene homo- or copolymer; and (b) 60-90 wt.% of one or more copolymers of ethylene with a C3-C10 alpha-olefin. The top layer (B) comprises a propylene polymer selected among propylene homopolymers, propylene copolymers with ethylene or a C4-C10 alpha-olefin and combinations thereof. The membrane has good tensile properties and good tear resistance.

[0005] Although being appreciated in terms of performances and being easily recyclable, polypropylene compositions give raise to concerns in terms of sustainability, due to the fact that the production of virgin propylene polymers is based on the use of non-renewable feedstocks. [0006] As a result, a common attempt to mitigate the problem is that of replacing, at least partially, virgin polypropylene compositions with variable amounts of recycled plastic materials deriving from streams of post-consumer or post-industrial wastes.

[0007] For instance, the patent application W02023/052083 discloses a propylene polymer composition having MFR ranging from 0.4 to 1.4 g/lOmin comprising (A) 65-95 wt.% of a polypropylene composition comprising 15-40 wt.% of a polymer fraction (a) being a propylene homo- or copolymer and 60-85 wt.% of a polymer fraction (b) comprising an ethylene/alpha-olefin copolymer containing less than 50 wt.% of ethylene, and (B) 5-30 wt.% of a recycled styrene block copolymer. The composition is suitable for roofing applications.

[0008] The applicant unexpectedly found that a polypropylene composition comprising a recycled polyethylene with low density has an improved property profile, which renders the polypropylene composition suitable for producing soft articles, like roofing sheets or geomembranes.

SUMMARY OF THE INVENTION

[0009] An object of the present disclosure is to provide a polypropylene composition (I) according to the appended independent claim and, preferably, according to any one of the claims directly or indirectly depending on the independent claim.

[0010] The polypropylene composition (I) of the present disclosure has improved tensile properties if compared with the polypropylene composition (A), while retaining softness and good weldability, and it is particularly suitable for producing extruded articles, like films or sheets.

[0011] A further object of the present disclosure is therefore an article, like a film or sheet, comprising the polypropylene composition (I), the article being preferably obtained by extrusion. [0012] While multiple embodiments are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description. As will be apparent, certain embodiments, as disclosed herein, are capable of modifications in various obvious aspects, all without departing from the spirit and scope of the claims as presented herein. Accordingly, the following detailed description is to be regarded as illustrative in nature and not restrictive. DETAILED DESCRIPTION OF THE INVENTION

[0013] In the context of the present disclosure;

[0014] - the percentages are expressed by weight, unless otherwise specified;

[0015] - the total weight of a polymer composition sums up to 100% by weight, unless otherwise specified;

[0016] - the term “comprising” referred to a polymer or to a polymer composition, mixture or blend should be construed to mean “comprising or consisting essentially of’;

[0017] - the term “consisting essentially of’ means that, in addition to those components which are mandatory, other components may also be present in the material, provided that the essential characteristics of the material are not materially affected by their presence. Examples of components that, when present in customary amounts, do not materially affect the characteristics of a polymer or of a polyolefin composition, mixture or blend are catalyst residues, antistatic agents and processing aids;

[0018] - the term “copolymer” is referred to a polymer deriving from the intentional polymerization of at least two different comonomers, i.e. the term “copolymer” includes terpolymers;

[0019] - the term “virgin” refers to a plastic material that originates from feedstock; that is, to a non-recycled material;

[0020] - the terms “pre-consumer waste” and “post-industrial waste” are synonyms and designate a material diverted from the waste stream originating from a manufacturing process. It might be material trimmings, faulty items, overstock raw materials, excess inventory, etc.;

[0021] - the term “post-consumer waste” designate a material that is discarded after it has been used by a final consumer;

[0022] - the term “PCR” or “post-consumer recycled” refers to a plastic material that has been converted into a product, used by the consumer, discarded and recovered by mechanical recycling; [0023] - “mechanical recycling” refers to operations that aim to recover plastic material via mechanical processes, like sorting, grinding, washing, separating, drying, re-granulating and compounding, thus producing PCRs that can be converted into plastics products;

[0024] - a “film” is thin layer of material having thickness lower than 1000 pm;

[0025] - a “sheet” is a layer of material having thickness equal to or greater than 1000 pm. [0026] The present disclosure provides a polyolefin composition (I) comprising or consisting of:

[0027] (A) from 65 to 95% by weight, preferably from 70 to 93% by weight, more preferably from 75 to 90% by weight, of a polypropylene composition having a melt flow rate MFR(A) (ISO 1133-1 :2011, 230°C/2.16 kg) ranging from 0.2 to 1.2 g/lOmin comprising or consisting of:

[0028] from 15 to 40% by weight, preferably from 25 to 35% by weight, of a polymer fraction (a) comprising a propylene polymer selected from a propylene homopolymer, a propylene copolymer and combinations thereof, the propylene copolymer containing up to and including 15.0% by weight, based on the weight of the polymer fraction (a), of units derived from a comonomer selected from ethylene, a CH2=CHR alpha-olefin, where R is a linear or branched C2- C8 alkyl group, and combinations thereof, the polymer fraction (a) having solubility in xylene at 25°C XS(a) equal to or lower than 10.0% by weight, based on the weight of the polymer fraction (a); and

[0029] from 60 to 85% by weight, preferably from 65 to 75% by weight of a polymer fraction (b) comprising a copolymer of ethylene with a comonomer selected from propylene, a CH2=CHR alpha-olefin, where R is a linear or branched C2-C8 alkyl group, and combinations thereof, the copolymer containing an amount of units deriving from ethylene equal to or lower than 40% by weight, based on the weight of the polymer fraction (b), the polymer fraction (b) having solubility in xylene at 25°C XS(b) equal to or greater than 60% by weight, based on the weight of the polymer fraction (b),

[0030] wherein the amounts of fractions (a) and (b) are based on the sum of the weights of fraction (a)+fraction (b); and

[0031] (B) from 5 to 35% by weight, preferably from 7 to 30% by weight, more preferably from 10 to 25% by weight, of a recycled ethylene polymer having density equal to or lower than 0.93 g/cm³ and a MFR(B) ranging from 0.1 to lO.O g/lOmin. (ISO 1133-1 :2011, 190°C/2.16 kg), [0032] wherein the amounts of (A) and (B) are based on the total weight of (A)+(B).

[0033] In the following the individual components (A) and (B) of the polyolefin composition (I) are defined in more detail. The individual components may be comprised in the polyolefin composition (I) in any combination. [0034] The polymer fraction (a) comprised in the polypropylene composition (A) preferably has at least one of, more preferably all, the following features:

[0035] - comprises a propylene copolymer containing from 0.5 to 10.0% by weight, preferably from 1.0 to 8.0% by weight, more preferably from 2.5 to 5.0% by weight, based on the weight of the fraction (a), of units deriving from a comonomer selected from ethylene, a CH2=CHR alphaolefin, where R is a linear or branched C2-C8 alkyl group, and combinations thereof, wherein the comonomer is preferably selected from ethylene, butene- 1, hexene- 1, octene- 1, 3 -methyl- 1- pentene and combinations thereof, ethylene being particularly preferred; and/or

[0036] - melt flow rate MFR(a) (ISO 1133-1:2011, 230°C/2.16 kg) ranging from 10 to 50 g/lOmin, more preferably from 15 to 40 g/lOmin and especially from 20 to 35 g/lOmin.

[0037] In addition to one or more of the properties above, the polymer fraction (a) optionally also has at least one of, more preferably all, the following features:

[0038] - poly dispersity index ranging from 3 to 6; and/or

[0039] - solubility in xylene at 25°C ranging from 0.5 to 8.0% by weight, preferably from 1.0 to 7.0% by weight, based on the weight of the polymer fraction (a); and/or

[0040] - an intrinsic viscosity of the fraction insoluble in xylene at 25°C ranging from 1.2 to

1.9 dl/g.

[0041] The polymer fraction (b) comprised in the polypropylene composition (A) preferably has at least one, more preferably all, the following features:

[0042] - comprises a copolymer of ethylene with a comonomer selected from propylene, butene- 1, hexene- 1 and combinations thereof, propylene being the most preferred; and/or

[0043] - the amount of ethylene in the copolymer ranges from 20.0 to 38.0% by weight, more preferably from 23.0 to 35.0% by weight, based on the weight of the copolymer; and/or

[0044] - solubility in xylene at 25°C of at most 80% by weight, based on the weight of the polymer fraction (b); and/or

[0045] - an intrinsic viscosity of the fraction soluble in xylene at 25°C equal to or greater than

2.0 dl/g and preferably ranging from 2.5 to 5.0 dl/g, more preferably from 2.8 to 4.0 dl/g.

[0046] Optionally, the polymer fraction (b) contains minor quantities, like from 0.1 to 10.0% by weight, based on the weight of the polymer fraction (b), of units deriving from a diene preferably selected from the group consisting of butadiene, 1,4-hexadiene, 1,5-hexadiene, ethylidene-l-norbonene and combinations thereof.

[0047] The polypropylene composition (A) preferably has at least one of, more preferably all, the following features:

[0048] - total ethylene content ranging from 15.0 to 28.0% by weight, more preferably from

16.0 to 23.0% by weight and especially from 17.0 to 22.0% by weight, based on the sum of the weights of fraction (a)+fraction (b); and/or

[0049] - melt flow rate MFR(A) (ISO 1133-1 :2011, 230°C/2.16 Kg) ranging from 0.3 to 1.0 g/lOmin; and/or

[0050] - tensile modulus in MD (ISO 527-1,-2) ranging from 80 to 130 MPa; and/or

[0051] - tensile stress at break in MD (ISO 527-1,-2) ranging from 10 to 25 N/mm²; and/or

[0052] - Shore A (ISO 868, 15 sec) higher than 80, preferably from 90 to 120; and/or

[0053] - Shore D (ISO 868, 15 sec) ranging from 25 to 40; and/or

[0054] - tear resistance in MD (ASTM DI 004) ranging from 50 to 100 N, preferably from 60 to 90 N.

[0055] In addition to one or more of the properties above, the polypropylene composition (A) optionally also has at least one of, preferably all, the following features:

[0056] - flexural modulus (ISO 178:2010 measured on Imm-thick extruded sheets) equal to or lower than 150 MPa, preferably ranging from 50 to 100 MPa; and/or

[0057] - Charpy impact strength at -20°C (ISO 179-1:2010 eA) of from 80 to 120 KJ/m²; and/or

[0058] - puncture resistance (max force) ranging from 150 to 350 N, preferably from 200 to

300 N measured on a Imm-thick extruded sheet according to method ASTM D 4833 (punch diameter: 8 mm, crosshead speed: 300 mm/min); and/or

[0059] - puncture resistance (deformation at break) ranging from 20 to 80 mm, preferably from

25 to 45 mm measured on a Imm-thick extruded sheet according to method ASTM D 4833 (punch diameter: 8 mm, crosshead speed: 300 mm/min).

[0060] The polypropylene composition (A) is preferably prepared by polymerizing the relevant monomers in sequential polymerization stages, with the second and each optional subsequent polymerization stage being conducted in the presence of the polymeric material formed in the immediately preceding polymerization stage. Preferably, the polymer fraction (a) is prepared in a first polymerization stage and the polymer fraction (b) is prepared in a second polymerization stage, each stage being carried out in the presence of the polymeric material prepared in the immediately preceding polymerization stage. The amounts of fractions (a) and (b) correspond to the split between the polymerization stages. Each polymerization stage is carried out in at least one polymerization reactor.

[0061] The polymerization stages are preferably carried out in the presence of a Ziegler-Natta catalyst. Preferably, all polymerization stages are carried out in the presence of a catalyst comprising the reaction product of:

[0062] i) a solid catalyst component comprising Ti, Mg, Cl, and at least an internal electron donor compound;

[0063] ii) an alkylaluminum compound and,

[0064] iii) an external electron-donor compound having the general formula (R¹)a(R²)bSi(OR³)_c, where a and b are integers from 0 to 2, c is an integer from 1 to 4 and the sum (a+b+c) is 4; R¹, R², and R³, are independently selected from alkyl, cycloalkyl or aryl radicals with 1-18 carbon atoms optionally containing heteroatoms.

[0065] The internal donor is preferably selected from the esters of mono or dicarboxylic organic acids such as benzoates, malonates, phthalates and certain succinates. Examples of internal donors are described in US4,522,930, EP045977A2 and international patent applications WOOO/63261 and W001/57099. Particularly suited are the phthalic acid esters, such as diisobutyl, dioctyl and diphenyl phthalate and benzyl-butyl phthalate.

[0066] The particles of solid component (i) may have substantially spherical morphology and average diameter ranging between 5 and 150pm, preferably from 20 to 100pm and more preferably from 30 to 90pm. As particles having substantially spherical morphology, those are meant wherein the ratio between the greater axis and the smaller axis is equal to or lower than 1.5 and preferably lower than 1.3.

[0067] According to one method, the solid catalyst component (i) can be prepared by reacting a titanium compound of formula Ti(OR)q-yXy, where q is the valence of titanium and y is a number between 1 and q, preferably TiCI-i, with a magnesium chloride deriving from an adduct of formula MgCh’pROH, where p is a number between 0.1 and 6, preferably from 2 to 3.5, and R is a hydrocarbon radical having 1-18 carbon atoms. The adduct can be suitably prepared in spherical form by mixing alcohol and magnesium chloride, operating under stirring conditions at the melting temperature of the adduct (100°-130°C). Then, the adduct is mixed with an inert hydrocarbon immiscible with the adduct thereby creating an emulsion which is quickly quenched causing the solidification of the adduct in form of spherical particles. Examples of spherical adducts prepared according to this procedure are described in USP4,399,054 and US4,469,648. The so obtained adduct can be directly reacted with Ti compound or it can be previously subjected to thermal controlled dealcoholation (80°-130°C) so as to obtain an adduct in which the number of moles of alcohol is of lower than 3, preferably between 0.1 and 2.5. The reaction with the Ti compound can be carried out by suspending the adduct (dealcoholated or as such) in cold TiCI-i; the mixture is heated up to 80°-130°C and kept at this temperature for 0.5-2 hours. The treatment with TiCh can be carried out one or more times. The electron donor compound can be added in the desired ratios during the treatment with TiCl-i.

[0068] The alkyl-Al compound (ii) is preferably chosen among the trialkyl aluminum compounds such as for example triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri- n-hexylaluminum, tri-n-octylaluminum. It is also possible to use alkylaluminum halides, alkylaluminum hydrides or alkylaluminum sesquichlorides, such as AlEt2Cl and AhEtsCh, possibly in mixture with the above cited trialkylaluminums. The Al/Ti ratio is higher than 1 and may preferably range between 50 and 2000.

[0069] Particularly preferred are the silicon compounds (iii) in which a is 1, b is 1, c is 2, at least one of R¹ and R² is selected from branched alkyl, cycloalkyl or aryl groups with 3-10 carbon atoms optionally containing heteroatoms and R³ is a C1-C10 alkyl group, in particular methyl. Examples of such preferred silicon compounds are methylcyclohexyldimethoxysilane (C donor), diphenyldimethoxysilane, methyl-t-butyldimethoxysilane, dicyclopentyldimethoxysilane (D donor), diisopropyldimethoxysilane, (2-ethylpiperidinyl)t-butyldimethoxysilane, (2- ethylpiperidinyl)thexyldimethoxysilane, (3,3,3-trifluoro-n-propyl)(2- ethylpiperidinyl)dimethoxysilane, methyl(3,3,3-trifluoro-n-propyl)dimethoxysilane.

[0070] Silicon compounds in which a is 0, c is 3, R² is a branched alkyl or cycloalkyl group, optionally containing heteroatoms, and R³ is methyl are also preferred. Examples of such preferred silicon compounds are cyclohexyltrimethoxysilane, t-butyltrimethoxysilane and thexyltrimethoxysilane.

[0071] The external electron donor compound (iii) is used in such an amount to give a molar ratio between the organoaluminum compound and said external electron donor compound (iii) of from 0.1 to 200, preferably from 1 to 100 and more preferably from 3 to 50.

[0072] Examples of polymerization processes for the preparation of said compositions can be found in EP472946A, the relevant part of which is incorporated herein by reference.

[0073] All the polymerization stages preferably occur in gas phase. The reaction temperature of each polymerization stage is independently selected from values from 40° to 90°C. The pressure of each polymerization stage independently ranges from 5 to 30 bar. The residence times of the two stages depend on the desired ratio between the fractions (a) and (b), and preferably range from 15 minutes to 8 hours. Conventional molecular weight regulators known in the art, such as chain transfer agents (e.g. hydrogen or ZnEt2), are optionally used.

[0074] If needed, the polymer obtained at the end of the polymerization reaction is optionally subject to a chemical treatment with organic peroxides in order to lower the average molecular weight and to increase the melt flow rate up to the value needed for specific applications.

[0075] The recycled ethylene polymer (B) originates from pre-consumer wastes, postconsumer wastes or from a combinations thereof, preferably from a post-consumer waste. In particular, the recycled ethylene polymer (B) originates from the mechanical recycling of at least one of the above-mentioned waste streams.

[0076] In a preferred embodiment, the PCR ethylene polymer (B) derives from mechanical recycling of flexible packaging, like cast films, blown films and BOPP films.

[0077] The recycled ethylene polymer (B) preferably has density ranging from 0.91 to 0.93 g/cm³ and/or a melt flow rate MFR(B) (ISO 1133-1:2011, 190°C/2.16 kg) ranging from 0.3 to 2.5 g/10min., preferably from 0.5 to 1.8 g/lOmin.

[0078] The ethylene polymer (B) preferably has a first peak melting temperature Tm(l) ranging from 105° to 115°C and a second peak melting temperature Tm(2) ranging from 118° to 128°C.

[0079] In addition to one or more of the properties above, the recycled ethylene polymer (B) optionally also has at least one, more preferably all, the following properties: [0080] - tensile modulus in MD (ISO 527-1,-2) ranging from 180 to 400 MPa, preferably from

200 to 300 MPa; and/or

[0081] - tensile stress at break in MD (ISO 527-1,-2) ranging from 15 to 25 MPa; and/or

[0082] - an ash content (ISO 3451-1 at 800°C) equal to or lower than 4.0% by weight, preferably ranging from 0.2 to 1.0% by weight, based on the weight of the recycled ethylene polymer (B).

[0083] Being a recycled material, the recycled ethylene polymer (B) optionally comprises a total amount up to and including 20% by weight, preferably from 1 to 15% by weight, more preferably from 2 to 10% by weight, based on the weight of the recycled ethylene polymer (B), of recycled polypropylene and/or an inorganic material.

[0084] The polyolefin composition (I) is preferably endowed with at least one of, more preferably all, the following features:

[0085] - melt flow rate MFR(I) (ISO 1133-1:2011, 230°C/2.16 kg) equal to or lower than 4.0 g/lOmin, preferably ranging from 0.1 to 3.0 g/10 min, more preferably from 0.3 to 1.0 g/lOmin; and/or

[0086] - Shore A (ISO 868, 15 sec) higher than 80, preferably from 85 to 120; and/or

[0087] - Shore D ISO 868, 15 sec) ranging from 25 to 35; and/or

[0088] - tensile modulus in MD (ISO 527-1,-2) ranging from 100 to 250 MPa, preferably from

120 to 200 MPa; and/or

[0089] - tensile stress at break in MD (ISO 527-1,-2) equal to or greater than 18 MPa, preferably ranging from more than 18 to 23 MPa; and/or

[0090] - elongation at break in MD (ISO 527-1, -2) equal to or greater than 700%, preferably ranging from 700 to 850%, more preferably from 730 to 800%.

[0091] Preferably, the polyolefin composition (I) is endowed with good welding properties, like a maximum strength, measured according to the method ASTM D 6392-08, equal to or greater than 200 N/25mm, preferably ranging from 200 to 300 N/25mm, and/or a maximum elongation according to the method ASTM D 6392-08, equal to or greater than 600%, preferably ranging from 650 to 850%.

[0092] Optionally, the polyolefin composition (I) comprises up to and including 5.0% by weight, more preferably from 0.01% to 5.0% by weight, of an additive (C) and/or up to and including 30% by weight, more preferably from 1.0 to 30% by weight, of a filler (D), wherein the amounts of (C) and (D) are based on the total weight of the polyolefin composition (I), the total weight being 100% by weight.

[0093] The additive (C) is preferably selected from the group consisting of nucleating agents, anti-oxidants, light stabilizers, slipping agents, anti-acids, melt stabilizers, pigments and combinations thereof, the amount of additive being based on the total weight of the polyolefin compositions (I).

[0094] The filler (D) is preferably selected from inorganic fillers, like glass fibers or carbon fibers; natural fillers, like wood or hemp; mineral fillers, like talc, and combinations thereof.

[0095] In one embodiment, the polyolefin composition (I) consists of the component (A), the component (B), optionally the additive (C) and optionally the filler (D).

[0096] The polyolefin composition (I) is obtained by mixing the components (A), (B), and optionally component (C) and/or (D), in a conventional melt mixing apparatus, like a single or twin screw extruder, operated under conventional conditions.

[0097] The polypropylene composition (I) of the present disclosure has good tensile properties and high softness, in combination with good welding properties, and it is especially suitable for producing extruded articles, like films or sheets.

[0098] Therefore, the present disclosure also refers to an article comprising or consisting of the polyolefin composition (I) as described above.

[0099] In one embodiment the article is obtained by extrusion.

[0100] Particularly preferably, the article is a film or sheet, more preferably for roofing applications.

[0101] The features describing the subject matter of the present disclosure are not inextricably linked to each other. Hence, preferred ranges of one feature may be combined with more or less preferred ranges of a different feature, independently from their level of preference.

EXAMPLES

[0102] The following examples are given to illustrate the present invention without limiting purpose. [0103] CHARACTERIZATION METHODS: the following methods are used to determine the properties indicated in the description, claims and examples.

[0104] Melt Flow Rate: Determined according to the method ISO 1133-1:2011 (230°C/2.16 kg for the propylene polymers and for the polyolefin composition (I), 190°C/2.16 kg for polyethylene).

[0105] Solubility in xylene at 25°C: 2.5 g of polymer sample and 250 ml of xylene are introduced in a glass flask equipped with a refrigerator and a magnetic stirrer. The temperature is raised in 30 minutes up to 135°C. The obtained clear solution is kept under reflux and stirring for further 30 minutes. The solution is cooled in two stages. In the first stage, the temperature is lowered to 100°C in air for 10 to 15 minute under stirring. In the second stage, the flask is transferred to a thermostatically controlled water bath at 25°C for 30 minutes. The temperature is lowered to 25°C without stirring during the first 20 minutes and maintained at 25°C with stirring for the last 10 minutes. The formed solid is filtered on quick filtering paper (eg. Whatman filtering paper grade 4 or 541). 100 ml of the filtered solution (SI) is poured in a previously weighed aluminum container, which is heated to 140°C on a heating plate under nitrogen flow, to remove the solvent by evaporation. The container is then kept on an oven at 80°C under vacuum until constant weight is reached. The amount of polymer soluble in xylene at 25 °C is then calculated. XS(I) and XSA values are experimentally determined. The fraction of component (B) soluble in xylene at 25 °C (XSB) can be calculated from the formula:

XS = W(A)X(XSA) + W(B)X(XSB) wherein W(A) and W(B) are the relative amounts of components (A) and (B), respectively, and W(A)+ W(B)=1.

[0106] Intrinsic viscosity of the xylene soluble fraction: to calculate the value of the intrinsic viscosity IV, the flow time of a polymer solution is compared with the flow time of the solvent (THN). A glass capillary viscometer of Ubbelohde type is used. The oven temperature is adjusted to 135°C. Before starting the measurement of the solvent flow time tO the temperature must be stable (135±0.2°C). Sample meniscus detection for the viscometer is performed by a photoelectric device.

[0107] Sample preparation: 100 ml of the filtered solution (SI) is poured in a beaker and 200 ml of acetone are added under vigorous stirring. Precipitation of insoluble fraction must be complete as evidenced by a clear solid-solution separation. The suspension is filtered on a weighed metallic screen (200 mesh), the beaker is rinsed and the precipitate is washed with acetone so that the o-xylene is completely removed. The precipitate is dried in a vacuum oven at 70°C until a constant weight is reached. 0.05g of precipitate are weighted and dissolved in 50ml of tetrahydronaphthalene (THN) at a temperature of 135°C. The efflux time t of the sample solution is measured and converted into a value of intrinsic viscosity [r|] using Huggins’ equation (Huggins, M.L., J. Am. Chem. Soc. 1942, 64, 11, 2716-2718) and the following data:

- concentration (g/dl) of the sample;

- the density of the solvent at a temperature of 135°C;

- the flow time tO of the solvent at a temperature of 135°C on the same viscometer.

One single polymer solution is used to determine [q],

[0108] Ethylene content of propylene-ethylene copolymers by NMR: ¹³C NMR spectra were acquired on a Bruker AV-600 spectrometer equipped with cryoprobe, operating at 160.91 MHz in the Fourier transform mode at 120°C. The peak of the SPP carbon (nomenclature according to “Monomer Sequence Distribution in Ethylene-Propylene Rubber Measured by 13C NMR. 3. Use of Reaction Probability Mode”, C. J. Carman, R. A. Harrington and C. E. Wilkes, Macromolecules, 1977, 10, 536) was used as internal reference at 29.9 ppm. The samples were dissolved in l,l,2,2-tetrachloroethane-d2 at 120°C with a 8 % wt/v concentration. Each spectrum was acquired with a 90° pulse, 15 seconds of delay between pulses and CPD to remove 1H-13C coupling. 512 transients were stored in 32K data points using a spectral window of 9000 Hz. The assignments of the spectra, the evaluation of triad distribution and the composition were made according to Kakugo (“Carbon- 13 NMR determination of monomer sequence distribution in ethylene-propylene copolymers prepared with 5-titanium trichloride- diethylaluminum chloride” M. Kakugo, Y. Naito, K. Mizunuma and T. Miyatake, Macromolecules, 1982, 15, 1150) using the following equations:

PPP = 100 Tpp/S PPE = 1OO TP5/S EPE = 100 T55/S

PEP = 100 SPP/S PEE= 100 SP5/S EEE = 100 (0.25 SyS+0.5 S55)/S

S = TPP + TP5 + T55 + SPP + SP5 + 0.25 Sy5 + 0.5 S55

[0109] The molar percentage of ethylene content was evaluated using the following equation: E% mol = 100 * [PEP+PEE+EEE] [0110] The weight percentage of ethylene content was evaluated using the following equation:

100 * E% mol * MWE

E% wt. = >

E% mol * MWE + P% mol * MWp

[0111] where P% mol is the molar percentage of propylene content, while MWE and MWp are the molecular weights of ethylene and propylene, respectively.

[0112] The product of reactivity ratio rm was calculated according to Carman (C. J. Carman,

R.A. Harrington and C.E. Wilkes, Macromolecules, 1977; 10, 536) as:

[0113] The tacticity of Propylene sequences was calculated as mm content from the ratio of the PPP mmTpp (28.90-29.65 ppm) and the whole Tpp (29.80-28.37 ppm).

[0114] Polydispersity index: Determined at a temperature of 200 °C by using a parallel plates rheometer model RMS-800 marketed by Rheometrics (USA), operating at an oscillation frequency which increases from 0.1 rad/sec to 100 rad/sec. From the crossover modulus one can derive the P.I. by way of the equation:

[0115] P.I.= 105/Gc

[0116] in which Gc is the crossover modulus which is defined as the value (expressed in Pa) at which G’=G” wherein G is the storage modulus and G" is the loss modulus.

[0117] Density: determined according to ISO 1183-l/A:2019 at 23°C.

[0118] Peak melting temperature: determined by Differential Scanning Calorimetry (DSC) according to the method ISO 11357-3:2018. Scanning rate of20°C/min in cooling and heating, on a sample weighting 5-7 mg, under nitrogen flow. Instrument calibration made with Indium.

[0119] Tensile properties: determined according to ISO 527-1, -2 on Imm-thick extruded sheets for the PP(A) and the polyolefin composition (I), and on injection molded specimens for the recycled polyethylene (B).

[0120] Shore A and Shore D: determined according to ISO 868, 15. sec.

[0121] Tear resistance: determined according to ASTM DI 004 on Imm-thick extruded sheets. Crosshead speed: 51 mm/min; V-shaped die cut specimen.

[0122] Ash content: determined with the method ISO 3451-1 at 800°C. [0123] Flexural Modulus: determined according to the method ISO 178:2010.

[0124] Charpy impact strength: determined according to ISO 179-1:2010 eA on Imm-thick extruded sheets.

[0125] Puncture resistance: measured on a Imm-thick extruded sheet according to method ASTM D 4833 (punch diameter: 8 mm, crosshead speed: 300 mm/min).

[0126] Preparation of extruded specimens: the polymer in form of granules are fed via feed hoppers into a Leonard extruder (mono-screw extruder, 40 mm in diameter and 27 L/D in length) where the polymer was first melted (melt temperature 230°C), compressed, mixed and finally metered out at a throughput rate of 10 Kg/h with a metering pump (15 cc/rpm). The molten polymer leaves the flat die (width 200 mm, die lip at 0.8-0.9 mm) and is instantly cooled through a vertical three-rolls calendrer having roll-temperature of 60°C. Imm-thick extruded sheets are obtained.

[0127] Preparation of injection molded specimens: test specimens 80 x 10 x 4 mm were obtained according to the method ISO 1873-2:2007.

[0128] Welding properties: measured with the test method ASTM D 6392-08, applying the following conditions: specimen width = 25 mm; thickness = 1 mm and gauge length = 50 mm. Every seam is obtained by welding together two pieces of sheet Imm-thick and 150 x 200 (mm) of dimensions. The seam is about 30 mm large, and the added weight is 5400g. The temperature of the weld is set at 280°C (hot air direct measure). A seam strength curve is acquired and the maximum strength, the average strength and the type of breakage are recorded. The testing speed is 3 m/min (T-Peel) and the values indicated in the tables are the mean values obtained by testing 5 samples for each material.

[0129] RAW MATERIALS

[0130] PP(A): the polypropylene composition (A) was prepared according to the procedure reported in in comparative example 1 of EP1279699A1. The polypropylene composition (A) comprises:

- 30% by weight of a polymer fraction (a) comprising a propylene-ethylene copolymer containing 3.2% by weight, based on the weight of the fraction (a), of units derived from ethylene, the fraction (a) having solubility in xylene at 25°C of 6.0% by weight, based on the weight of fraction (a), and MFR(a) of 25 g/10 mm. (ISO1133-l:2011, 230°C/2.16Kg); and - 70% by weight of a polymer fraction (b) comprising an ethylene-propylene copolymer containing 27% by weight of units derived from ethylene, based on the weight of the fraction (b), the polymer fraction (b) having solubility in xylene at 25°C of 64% by weight, based on the weight of the fraction (b), wherein the fraction soluble in xylene has intrinsic viscosity of 3.2 dl/g, and wherein the amounts of polymer fraction (a) and (b) are based on the sum of the weights of fraction (a) + fraction (b). The characterization of the composition is reported in table 1.

The polymer was additivated with 0.05 wt.% calcium stearate, 0.05 wt.% of Irganox 1010 (pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate)) by BASF and 0.1 wt.% of Irgafos 168 (tris(2,4-di-tert-butylphenyl) phosphite) by BASF.

[0131] rPE(l): a recycled ethylene polymer having density of 0.924 g/cm³, MFR of 1.4 g/lOmin (ISO1133-1:2011, 190°C/2.16Kg) originating from mechanical recycling of post commercial films. The rPE(l) has tensile modulus (ISO 527-1,-2) of 220 MPa, tensile stress at break (ISO 527-1,-2) of 16.9 MPa, elongation at break (ISO 527-1,-2) of 400% and an ash content of 0.4% by weight. The rPE has first melting peak temperature of 110°C and a second melting peak temperature of 123°C.

[0132] rPE(2): a recycled ethylene polymer having density of 0.92 g/cm³, MFR of 0.6 g/lOmin

(ISO1133-1:2011, 190°C/2.16Kg) originating from mechanical recycling of post-consumer polyethylene films. The rPE(2) has tensile modulus (ISO 527-1,-2) of 230 MPa, tensile stress at break (ISO 527-1,-2) of 18.6 MPa, elongation at break (ISO 527-1,-2) of 430% and an ash content of 2.4% by weight. The rPE has first melting peak temperature of 110°C and a second melting peak temperature of 121°C.

[0133] Lupolen 2420F marketed by LyondellBasell, a virgin low density polyethylene with density 0.923 g/cm³ (ISO 1183-1), MFR (ISO1133-1:2011, 190°C/2.16Kg) 0.75 g/lOmin. and tensile modulus (ISO 527-1,-2) of 220 MPa. The product has peak melting temperature of 111°C (ISO 11357-3).

[0134] Lupolen 2420H marketed by LyondellBasell, a virgin low density polyethylene with density 0.924 g/cm³ (ISO 1183-1), MFR (ISO1133-E2011, 190°C/2.16Kg) of 1.9 g/lOmin. and tensile modulus of 260 MPa (ISO 527-1,-2). The product has peak melting temperature of 111°C. [0135] Examples E1-E3 [0136] The rPE was melt blended with the polypropylene composition (A) in a Berstorff three twin screw extruder, at a rotation speed of 250 rpm and a melt temperature of 200-250°C. Compositions, mechanical and welding properties are reported in table 1 and compared with the properties of the polypropylene composition (A).

[0137] Comparative examples CE4-CE5

[0138] In comparative examples, virgin low density polyethylenes were melt blended with the polypropylene composition (A) as described for the examples E1-E3. Compositions, mechanical and welding properties are reported in table 1.

Table 1

Claims

CLAIMS What is claimed is:

1. A polyolefin composition (I) comprising:

(A) from 65 to 95% by weight of a polypropylene composition having a melt flow rate MFR(A) (ISO 1133-1 :2011, 230°C/2.16 kg) ranging from 0.2 to 1.2 g/lOmin comprising:

- from 15 to 40% by weight, preferably from 25 to 35% by weight, of a polymer fraction (a) comprising a propylene polymer selected from a propylene homopolymer, a propylene copolymer and combinations thereof, the propylene copolymer containing up to and including 15.0% by weight, based on the weight of the polymer fraction (a), of units derived from a comonomer selected from ethylene, a CH2=CHR alpha-olefin, where R is a linear or branched C2-C8 alkyl group, and combinations thereof, the polymer fraction

(a) having solubility in xylene at 25°C XS(a) equal to or lower than 10.0% by weight, based on the weight of the polymer fraction (a); and

- from 60 to 85% by weight, preferably from 65 to 75% by weight of a polymer fraction

(b) comprising a copolymer of ethylene with a comonomer selected from propylene, a CH2=CHR alpha-olefin, where R is a linear or branched C2-C8 alkyl group, and combinations thereof, the copolymer containing an amount of units deriving from ethylene equal to or lower than 40% by weight, based on the weight of the polymer fraction (b), the polymer fraction (b) having solubility in xylene at 25°C XS(b) equal to or greater than 60% by weight, based on the weight of the polymer fraction (b), wherein the amounts of fractions (a) and (b) are based on the sum of the weights of fraction (a)+fraction (b); and

(B) from 5 to 35% by weight of a recycled ethylene polymer having density equal to or lower than 0.93 g/cm³ and a melt flow rate MFR(B) ranging from 0.1 to 10.0 g/lOmin. (ISO 1133- 1:2011, 190°C/2.16 kg), wherein the amounts of (A) and (B) are based on the total weight of (A)+(B).

2. The polyolefin composition (I) according to claim 1 comprising:

- from 70 to 93% by weight, preferably from 75 to 90% by weight, of the polypropylene composition (A), and - from 7 to 30% by weight, preferably from 10 to 25% by weight, of the recycled ethylene polymer (B), wherein the amounts of (A) and (B) are based on the total weight of (A)+(B).

3. The polyolefin composition (I) according to claim 1 or 2, wherein the polymer fraction (a) comprises a propylene copolymer containing from 0.5 to 10.0% by weight, preferably from 1.0 to 8.0% by weight, more preferably from 2.5 to 5.0% by weight, based on the weight of the fraction (a), of a units deriving from a comonomer selected from ethylene, a CH2=CHR alpha-olefin, where R is a linear or branched C2-C8 alkyl group, and combinations thereof, wherein the comonomer is preferably selected from ethylene, butene- 1, hexene- 1, octene- 1, 3 -methyl- 1 -pentene and combinations thereof, ethylene being particularly preferred.

4. The polyolefin composition according to any one of the preceding claims, wherein the polymer fraction (a) has a melt flow rate MFR(a) (ISO 1133-1:2011, 230°C/2.16 kg) ranging from 10 to 50 g/lOmin, more preferably from 15 to 40 g/lOmin and especially from 20 to 35 g/lOmin.

5. The polyolefin composition (I) according to any one of the preceding claims, wherein the polymer fraction (b) has at least one of the following features:

- comprises a copolymer of ethylene with a comonomer selected from propylene, butene- 1, hexene- 1 and combinations thereof, propylene being the most preferred; and/or

- the amount of ethylene in the copolymer ranges from 20.0 to 38.0% by weight, more preferably from 23.0 to 35.0% by weight, based on the weight of the copolymer; and/or

- solubility in xylene at 25°C of at most 80% by weight, based on the weight of the polymer fraction (b); and/or

- intrinsic viscosity of the fraction soluble in xylene at 25°C equal to or greater than 2.0 dl/g and preferably ranging from 2.5 to 5.0 dl/g, more preferably from 2.8 to 4.0 dl/g.

6. The polyolefin composition (I) according to any one of the preceding claims, wherein the polypropylene composition (A) has at least one of the following features: - total ethylene content ranging from 15.0 to 28.0% by weight, more preferably from 16.0 to 23.0% by weight and especially from 17.0 to 22.0% by weight, based on the sum of the weights of fraction (a)+fraction (b); and/or

- melt flow rate MFR(A) (ISO 1133-1 :2011, 230°C/2.16 Kg) ranging from 0.3 to 1.0 g/lOmin; and/or

- tensile modulus in MD (ISO 527-1,-2) ranging from 80 to 130 MPa; and/or

- tensile stress at break in MD (ISO 527-1,-2) ranging from 10 to 25 MPa; and/or

- Shore A (ISO 868, 15 sec) greater than 80, preferably ranging from 90 to 120; and/or

- Shore D (ISO 868, 15 sec) ranging from 25 to 40; and/or

- tear resistance in MD (ASTM DI 004) ranging from 50 to 100 N more preferably from 60 to 90 N.

7. The polyolefin composition (I) according to any one of the preceding claims, wherein the recycled ethylene polymer (B) has density ranging from 0.91 to 0.93 g/cm³ and/or a melt flow rate MFR(B) (ISO 1133-1 :2011, 190°C/2.16 kg) ranging from 0.3 to 2.5 g/10min., preferably from 0.5 to 1.8 g/lOmin.

8. The polyolefin composition (I) according to any one of the preceding claims, wherein the ethylene polymer (B) has a first peak melting temperature Tm(l) ranging from 105° to 115°C and a second peak melting temperature Tm(2) ranging from 118° to 128°C.

9. The polyolefin composition (I) according to any one of the preceding claims, wherein the recycled ethylene polymer (B) has at least one of the following features:

- a tensile modulus in MD (ISO 527-1,-2) ranging from 180 to 400 MPa, preferably from 200 to 300 MPa; and/or

- tensile stress at break in MD (ISO 527-1,-2) ranging from 15 to 25 MPa; and/or

- an ash content (ISO 3451-1) equal to or lower than 4.0% by weight, preferably ranging from 0.2 to 1.0% by weight, based on the weight of the recycled ethylene polymer (B).

10. The polyolefin composition (I) according to any one of the preceding claims having at least one of the following features:

- a melt flow rate MFR(I) (ISO 1133-1:2011, 230°C/2.16 kg) equal to or lower than 4.0 g/lOmin, preferably ranging from 0.1 to 3.0 g/10 min, more preferably from 0.3 to 1.0 g/lOmin; and/or

- Shore A (ISO 868, 15 sec) higher than 80, preferably ranging from 85 to 120; and/or

- Shore D (ISO 868, 15 sec) ranging from 25 to 35; and/or

- tensile modulus in MD (ISO 527-1,-2) ranging from 100 to 250 MPa, preferably from 120 to 200 MPa; and/or

- tensile stress at break in MD (ISO 527-1,-2) equal to or greater than 18 MPa, preferably ranging from more than 18 to 23 MPa; and/or

- elongation at break inMD (ISO 527-1, -2) equal to or greater than 700%, preferably ranging from 700 to 850%, more preferably from 730 to 800%.

11. An article comprising the polyolefin composition (I) according to any one of claims 1-10.

12. The article according to claim 11, which is obtained by extrusion.

13. The article according to claim 11 or 12, which is a film or sheet for roofing applications.