Patent Description:
Water management systems, in particular injection-moulded infiltration units used in underground systems, allow for temporary water storage and are capable of limiting the outflow in case of heavy rainfalls, or as an alternative for domestic drains to allow water, e.g. stormwater, infiltrate into the soil.

Polyolefin compositions suitable for these applications should be endowed with high thermo-oxidative stability as well as showing sufficient flow properties, high flexural modulus, good impact strength and long-term creep resistance.

Isotactic polypropylene, though being endowed with an exceptional combination of properties, is affected by the drawback of possessing an insufficient impact resistance at relatively low temperatures.

However, polypropylene compositions to be used in the water management system field, are of a high-performance level and should possess a satisfactory balance of high thermo-oxidative stability, sufficient flow properties, good creep resistance, high flexural modulus and good impact strength.

According to <CIT>, polyolefin compositions meeting the needs are those comprising (per cent by weight):.

In general, polyolefin compositions, although being appreciated in terms of performances, give raise to concerns in terms of sustainability with particular reference to the fact that their production is based on the use of non-renewable sources.

As a result, a common attempt to mitigate the problem is that of using, in multicomponent polyolefin compositions, variable amounts of recycled polyolefins such as polypropylene or polyethylene.

The recycled polyolefin derive from streams of post-consumer waste (PCW) material that undergoes various step of separation from other polymers, such as PVC, PET or PS.

One of the key problems in polyolefin recycling, especially when dealing with material streams from post-consumer waste (PCW) is the difficulty to quantitatively separate polypropylene (PP) from polyethylene (PE) and vice-versa. Thus, although named recycled PE (rPE) or recycled PP (rPP), the commercially available products from PCW sources have been found to be mixtures of PP and PE in various amounts.

This fact, associated to the presence in the recycled material of additives and minor components that may not be totally suitable for the application in which they are supposed to be used, leads to the consequence that such recycled PP/PE-blends normally suffer from deteriorated mechanical and optical properties and poor compatibility between the main polymer phases during remolding. The result is a perceived lower reliability of articles coming from the use of r-PP or r-PE due to the lower performances of the compositions from which they derive.

As a consequence, the use of recycled material in applications requiring a high-performance level, is strongly discouraged and limited to low-cost and non-demanding applications.

It has now been unexpectedly found that it in certain polypropylene compositions suitable for the use in water management systems, the presence of a recycled PE component does not impair the performances and allows the process for their production to be more sustainable.

It is therefore an object of the present disclosure a polypropylene composition comprising (per cent by weight):.

The term "copolymer" as used herein refers to both polymers with two different recurring units and polymers with more than two different recurring units, such as terpolymers, in the chain. By "ambient temperature" is meant therein a temperature of about <NUM> (room temperature).

By the term "crystalline propylene polymer" is meant in the present application a propylene polymer having an amount of isotactic pentads (mmmm), measured by <NUM>C-MNR on the fraction insoluble in xylene at <NUM>° C, higher than <NUM> molar %; by "elastomeric" polymer is meant a polymer having solubility in xylene at ambient temperature higher than <NUM> wt%.

All features of the copolymers (a)-(c) are not inextricably linked to each other. This means that a certain level of preference of one the features should not necessarily involve the same level of preference of the remaining features.

Crystalline propylene polymer (a) is selected from a propylene homopolymer and a copolymer of propylene containing at most <NUM> wt% of ethylene or a C<NUM>-C<NUM> α-olefin or combination thereof. Particularly preferred is the propylene homopolymer.

Preferably, in the component (a) amount of isotactic pentads (mmmm), measured by <NUM>C-MNR on the fraction insoluble in xylene at <NUM>° C, is higher than <NUM> molar% and preferably higher than <NUM> molar %.

Preferably, the propylene polymer (a) shows a molecular weight distribution, expressed by the ratio between the weight average molecular weight and numeric average molecular weight, (Mw/Mn), measured by GPC, equal to or higher than <NUM>, in particular from <NUM> to <NUM>.

Preferably, the polydispersity Index ranges from <NUM> to <NUM>.

The melt flow rate (ISO <NUM><NUM>/<NUM>) of crystalline propylene polymer (a) may range from <NUM> to <NUM>/<NUM>.

Elastomeric ethylene-propylene copolymer (b) can optionally comprise a diene. When present, the diene may be present in amounts ranging from <NUM> to <NUM> wt% with respect to the weight of copolymer (b). The diene can be conjugated or not and is selected from butadiene, <NUM>,<NUM>-hexadiene, <NUM>,<NUM>-hexadiene, and ethylidene-norbornene-<NUM>, for example.

Copolymer (b) exhibits a fraction insoluble in xylene at ambient temperature that is preferably less than <NUM> wt %, preferably equal to or lower than <NUM> wt % of the whole (b) copolymer. The intrinsic viscosity of the xylene soluble fraction at <NUM> preferably ranges from <NUM> to <NUM>, preferably from <NUM> to <NUM>, and more preferably from <NUM> to <NUM> dl/g. The amount of ethylene of the copolymer (b) may range from <NUM> to <NUM>%wt preferably from <NUM> to <NUM>%wt.

The r-PE (c) is crystalline or semicrystalline high density PE (r-HDPE) selected from commercial PCW (Post Consumer Waste for example from municipality).

Prior its use, the plastic mixture containing rHDPE undergoes standard recycling process including collection, shredding, sorting and washing. Although the sorted rHDPE is constituted by a large preponderance of HDPE it invariably contains minor amounts of other polymeric and/or inorganic components. In particular, the r-PE according to the present disclosure, contains inclusion of polypropylene in an amount from <NUM> to <NUM>% wt preferably from <NUM>% up to <NUM>%wt of the total r-PE component.

In a preferred embodiment, the r-PE includes a crystalline polyethylene fraction in which in which the amount of recurring units derived from propylene in the polyethylene chains is lower than <NUM>%wt and most preferably they are absent, i. e, most preferably r-PE is ethylene homopolymer containing the above mentioned inclusions. Preferably, the (r-PE) has a melt flow rate (<NUM>/<NUM> ISO <NUM>-<NUM>) from <NUM> to <NUM>/<NUM>' and more preferably from <NUM> to <NUM>/<NUM>'.

Moreover, the r-PE is preferably characterized by a density ranging from <NUM> to <NUM>/cm<NUM>, more preferably in the range <NUM> to <NUM>/cm<NUM> (ISO <NUM>-<NUM>).

The r-PE is commercially available. An example of a suitable r-PE grade is represented by the grade sold by Lyondellbasell under the tradename Hostalen QCP5603 in the ivory or grey versions.

The composition of the present disclosure preferably shows a tensile modulus value of at least <NUM> MPa, preferably higher than <NUM> MPa, even more preferably higher than <NUM> MPa, such as from <NUM> to <NUM> MPa.

The value of Charpy impact resistance at <NUM>° C is preferably higher than <NUM> kJ/m<NUM>, preferably from higher than <NUM> to <NUM> kJ/m<NUM> , while the Charpy impact resistance at <NUM>° C is preferably more than <NUM> kJ/m<NUM>, preferably more than <NUM> to <NUM> kJ/m<NUM>, and the Charpy impact resistance at -<NUM>° C is preferably from at least <NUM> to <NUM> kJ/m<NUM>.

The composition of the present disclosure exhibits a tensile strength at yield equal to or higher than <NUM> MPa, an elongation at yield equal to or higher than <NUM>%, a tensile strength at break equal to or higher than <NUM>, preferably higher than <NUM> MPa, and an elongation at break equal to or higher than <NUM>%, preferably higher than <NUM>%.

The composition of the present disclosure can be obtained by mechanical blending of the components (a)-(c) according to known techniques.

According to a preferred method of preparation, component (c) is mechanically blended with a preformed heterophasic composition comprising components (a) and (b) associated together by means of a sequential copolymerization process.

The said process comprises polymerizing propylene alone or in mixture with a low amount of ethylene in a first stage and then, in a second stage, polymerizing propylene with a higher amount of ethylene, both stages being conducted in the presence of a catalyst comprising the product of the reaction between:.

The internal donor is preferably selected from the esters of mono or dicarboxylic organic acids such as benzoates, malonates, phthalates and certain succinates. Internal electron donors are described in <CIT>, <CIT> and international patent applications <CIT> and <CIT>, for example. Particularly suited are the phthalic acid esters and succinate acids esters. Alkylphthalates are preferred, such as diisobutyl, dioctyl and diphenyl phthalate and benzyl-butyl phthalate.

The particles of solid component (i) may have substantially spherical morphology and average diameter ranging between <NUM> and <NUM>, preferably from <NUM> to <NUM> and more preferably from <NUM> to <NUM>. 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 <NUM> and preferably lower than <NUM>.

The amount of Mg may preferably range from <NUM> to <NUM>% more preferably from <NUM> to <NUM>%wt.

The amount of Ti may range from <NUM> to <NUM>% and more preferably from <NUM> to <NUM>%wt.

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 <NUM> and q, preferably TiCl<NUM>, with a magnesium chloride deriving from an adduct of formula MgCl<NUM>•pROH, where p is a number between <NUM> and <NUM>, preferably from <NUM> to <NUM>, and R is a hydrocarbon radical having <NUM>-<NUM> 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 (<NUM>-<NUM>). 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 <CIT> and <CIT>. The so obtained adduct can be directly reacted with Ti compound or it can be previously subjected to thermal controlled dealcoholation (<NUM>-<NUM>) so as to obtain an adduct in which the number of moles of alcohol is of lower than <NUM>, preferably between <NUM> and <NUM>. The reaction with the Ti compound can be carried out by suspending the adduct (dealcoholated or as such) in cold TiCl<NUM>; the mixture is heated up to <NUM>-<NUM> and kept at this temperature for <NUM>-<NUM> hours. The treatment with TiCl<NUM> can be carried out one or more times. The electron donor compound can be added in the desired ratios during the treatment with TiCl<NUM>.

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 AlEt<NUM>Cl and Al<NUM>Et<NUM>Cl<NUM>, possibly in mixture with the above cited trialkylaluminums. The Al/Ti ratio is higher than <NUM> and may preferably range between <NUM> and <NUM>.

Particularly preferred are the silicon compounds (iii) in which a is <NUM>, b is <NUM>, c is <NUM>, at least one of R<NUM> and R<NUM> is selected from branched alkyl, cycloalkyl or aryl groups with <NUM>-<NUM> carbon atoms optionally containing heteroatoms and R<NUM> is a C<NUM>-C<NUM> alkyl group, in particular methyl. Examples of such preferred silicon compounds are methylcyclohexyldimethoxysilane (C donor), diphenyldimethoxysilane, methyl-t-butyldimethoxysilane, dicyclopentyldimethoxysilane (D donor), diisopropyldimethoxysilane, (<NUM>-ethylpiperidinyl)t-butyldimethoxysilane, (<NUM>-ethylpiperidinyl)thexyldimethoxysilane, (<NUM>,<NUM>,<NUM>-trifluoro-n-propyl)(<NUM>-ethylpiperidinyl)dimethoxysilane, methyl(<NUM>,<NUM>,<NUM>-trifluoro-n-propyl)dimethoxysilane. Moreover, are also preferred the silicon compounds in which a is <NUM>, c is <NUM>, R<NUM> is a branched alkyl or cycloalkyl group, optionally containing heteroatoms, and R<NUM> is methyl. Examples of such preferred silicon compounds are cyclohexyltrimethoxysilane, t-butyltrimethoxysilane and thexyltrimethoxysilane.

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 <NUM> to <NUM>, preferably from <NUM> to <NUM> and more preferably from <NUM> to <NUM>.

The polymerization process can be carried out in gas-phase, operating in one or more fluidized or mechanically agitated bed reactors, slurry polymerization using as diluent an inert hydrocarbon solvent, or bulk polymerization using the liquid monomer (for example propylene) as a reaction medium.

Preferably, the heterophasic composition used in the present disclosure is obtained with a sequential polymerization process in two or more stages in which component (a) is obtained in the first stage and then component (b) is obtained in the second stage in the presence of component (a). Each stage can be in gas-phase, operating in one or more fluidized or mechanically agitated bed reactors, or bulk polymerization using the liquid monomer (for example propylene) as a reaction medium. Also preferred are hybrid processes in which one stage, preferably that in which component (a) is prepared, is carried out in liquid monomer and another stage, preferably that in which the component (b) is prepared, is carried out in gas-phase.

According to a preferred embodiment component (a) is prepared in a gas-phase reactor, as described <CIT>, comprising a first and in a second interconnected polymerization zone to which propylene and optionally ethylene are fed in the presence of a catalyst system and from which the polymer produced is discharged. The growing polymer particles flow through the first of said polymerization zones (riser) under fast fluidization conditions, leave said first polymerization zone and enter the second of said polymerization zones (downcomer) through which they flow in a densified form under the action of gravity, leave said second polymerization zone and are reintroduced into said first polymerization zone, thus establishing a circulation of polymer between the two polymerization zones. Generally, the conditions of fast fluidization in the first polymerization zone is established by feeding the monomers gas mixture below the point of reintroduction of the growing polymer into said first polymerization zone. The velocity of the transport gas into the first polymerization zone is higher than the transport velocity under the operating conditions and is normally between <NUM> and <NUM>/s. In the second polymerization zone, where the polymer flows in densified form under the action of gravity, high values of density of the solid are reached which approach the bulk density of the polymer; a positive gain in pressure can thus be obtained along the direction of flow, so that it becomes possible to reintroduce the polymer into the first reaction zone without the help of mechanical means. In this way, a "loop" circulation is set up, which is defined by the balance of pressures between the two polymerization zones and by the head loss introduced into the system. Optionally, one or more inert gases, such as nitrogen or an aliphatic hydrocarbon, are maintained in the polymerization zones, in such quantities that the sum of the partial pressures of the inert gases is preferably between <NUM> and <NUM>% of the total pressure of the gases. Preferably, the various catalyst components are fed to the first polymerization zone, at any point of said first polymerization zone. However, they can also be fed at any point of the second polymerization zone. Molecular weight regulators known in the art, particularly hydrogen, can be used to regulate the molecular weight of the growing polymer. Should a bimodal set-up be desired the use of a barrier stream as described <CIT> separating the polymerization environment of riser and downer can be used.

In the second stage of the particularly preferred polymerization process, the propylene/ethylene copolymer (b) is produced in a conventional fluidized-bed gas-phase reactor in the presence of the polymeric material and the catalyst system coming from the preceding polymerization step. The polymerization mixture is discharged from the downcomer to a gas-solid separator, and subsequently fed to the fluidized-bed gas-phase reactor operating under conventional conditions of temperature and pressure.

The polymerization is generally carried out at temperature of from <NUM> to <NUM>, preferably of from <NUM> to <NUM>. When the polymerization is carried out in gas-phase the operating pressure is generally between <NUM> and <NUM> MPa, preferably between <NUM> and <NUM> Mpa. In the bulk polymerization the operating pressure may range between <NUM> and <NUM> Mpa, preferably between <NUM> and <NUM> Mpa. Hydrogen can be used as a molecular weight regulator.

The final composition comprising the components (a)-(c) may be added with conventional additives, fillers and pigments, conventionally used in olefin polymers such as nucleating agents, extension oils, mineral fillers, and other organic and inorganic pigments. In particular, the addition of inorganic fillers, such as talc, calcium carbonate and mineral fillers, also brings about an improvement to some mechanical properties, such as flexural modulus and HDT. Talc can also have a nucleating effect.

The nucleating agents are added to the compositions of the present disclosure in quantities ranging from <NUM> to <NUM>% by weight, more preferably from <NUM> to <NUM>% by weight, with respect to the total weight, for example.

The polypropylene composition object of the present disclosure can be used for obtaining underground water management system such as tanks, containers and pipes possibly associated in infiltration units. As shown in the examples below, the composition employing r-PE does not show any worsening of the properties with respect to compositions employing virgin PE with similar features. The items of the present disclosure can be used also for management of different type of fluids provided that they are compatible with polyolefins.

Thus a further object of the present disclosure relates to items that can be used in fluid management systems made of the compositions of the present disclosure.

Such items can be manufactured according to manufacturing techniques such as injection molding (tanks, containers) or extrusion (pipes). Preferably, they are used to manage water and in particular the items are associated to form underground water management systems.

The following examples are given in order to illustrate, but not limit the present disclosure.

<NUM> of polymer and <NUM> of xylene are introduced in a glass flask equipped with a refrigerator and a magnetic stirrer. The temperature is raised in <NUM> minutes up to the boiling point of the solvent. The resulting clear solution is then kept under reflux and stirred for <NUM> minutes. The closed flask is then kept for <NUM> minutes in a bath of ice and water, then in a thermostatic water bath at <NUM> for <NUM> minutes. The resulting solid is filtered on quick filtering paper. <NUM> of the filtered liquid is poured in a previously weighed aluminum container, which is heated on a heating plate under nitrogen flow to remove the solvent by evaporation. The container is then kept on an oven at <NUM> under vacuum until a constant weight is obtained. The weight percentage of polymer soluble in xylene at room temperature is then calculated.

The content of the xylene-soluble fraction is expressed as a percentage of the original <NUM> grams and then, by the difference (complementary to <NUM>%), the xylene insoluble percentage (%);.

XS of components B) and C) have been calculated by using the formula:
<MAT>
wherein Wa, Wb and Wc are the relative amount of components A, B and C, respectively, and (A+B+C=<NUM>).

Measured according to ISO <NUM> at <NUM> with a load of <NUM>, unless otherwise specified.

The sample is dissolved in tetrahydronaphthalene at <NUM> and then poured into a capillary viscometer. The viscometer tube (Ubbelohde type) is surrounded by a cylindrical glass jacket; this setup allows for temperature control with a circulating thermostatic liquid. The downward passage of the meniscus is timed by a photoelectric device.

The passage of the meniscus in front of the upper lamp starts the counter which has a quartz crystal oscillator. The meniscus stops the counter as it passes the lower lamp and the efflux time is registered: this is converted into a value of intrinsic viscosity through Huggins' equation (<NPL>) provided that the flow time of the pure solvent is known at the same experimental conditions (same viscometer and same temperature). One single polymer solution is used to determine [ η ].

Polydispersity index: Determined at a temperature of <NUM> by using a parallel plates rheometer model RMS-<NUM> marketed by RHEOMETRICS (USA), operating at an oscillation frequency which increases from <NUM> rad/sec to <NUM> rad/sec. From the crossover modulus one can derive the P. by way of the equation: <MAT> 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.

<NUM>C NMR spectra were acquired on a Bruker AV-<NUM> spectrometer equipped with cryoprobe, operating at <NUM> in the Fourier transform mode at <NUM>.

The peak of the Sββ carbon (nomenclature according to "<NPL>) was used as internal reference at <NUM> ppm. The samples were dissolved in <NUM>,<NUM>,<NUM>,<NUM>-tetrachloroethane-d2 at <NUM> with a <NUM> % wt/v concentration. Each spectrum was acquired with a <NUM>° pulse, <NUM> seconds of delay between pulses and CPD to remove <NUM>-13C coupling. <NUM> transients were stored in <NUM> data points using a spectral window of <NUM>.

The assignments of the spectra, the evaluation of triad distribution and the composition were made according to Kakugo ("<NPL>) using the following equations:.

The molar percentage of ethylene content was evaluated using the following equation:
E% mol = <NUM> * [PEP+PEE+EEE]The weight percentage of ethylene content was evaluated using the following equation: <MAT>
where P% mol is the molar percentage of propylene content, while MWE and MWP are the molecular weights of ethylene and propylene, respectively.

The product of reactivity ratio r<NUM>r<NUM> was calculated according to Carman (<NPL>) as: <MAT>.

The tacticity of Propylene sequences was calculated as mm content from the ratio of the PPP mmTββ (<NUM>-<NUM> ppm) and the whole Tββ (<NUM>-<NUM> ppm).

Ethylene C2 content of component b2 has been measured by measuring the C2 content on component B) and then calculated by using the formula C2tot= Xb <NUM> C2b <NUM> + Xb2C2b2 wherein Xb1 and Xb2 are the amounts of components b1 and b2 in the composition.

Samples have been obtained according to ISO <NUM>-<NUM>:<NUM>.

The melting point has been measured by using a DSC instrument according to ISO <NUM>-<NUM>, at scanning rate of <NUM>/min both in cooling and heating, on a sample of weight between <NUM> and <NUM>. , under inert N<NUM> flow. Instrument calibration made with Indium.

The peak of the CH<NUM> ethylene was used as internal reference at <NUM> ppm. The samples were dissolved in <NUM>,<NUM>,<NUM>,<NUM>-tetrachloroethane-d2 at <NUM> with a <NUM> % wt/v concentration. Each spectrum was acquired with a <NUM>° pulse, <NUM> seconds of delay between pulses and CPD to remove <NUM>H-<NUM>C coupling. <NUM> transients were stored in <NUM> data points using a spectral window of <NUM>.

Molar composition was obtained according to the following using peak areas (table <NUM>): <MAT> <MAT> Where S = <NUM>. 5A<NUM> +A<NUM>.

Molar content was transformed in weight using monomers molecular weight.

In a plant operating continuously according to the mixed liquid-gas polymerization technique, runs were carried out under the conditions specified in Table <NUM>.

The polymerization was carried out in the presence of a catalyst system in a series of two reactors equipped with devices to transfer the product from one reactor to the one immediately next to it.

Into a <NUM> four-necked round flask, purged with nitrogen, <NUM> of TiCl<NUM> are introduced at <NUM>° C. While stirring, <NUM> of microspheroidal MgCl<NUM>·<NUM>. 9C<NUM>H<NUM>OH (prepared according to the method described in ex. <NUM> of <CIT> but operating at <NUM> rpm instead of <NUM> rpm) and <NUM> mmol of diethyl <NUM>,<NUM>-(diisopropyl)succinate are added. The temperature is raised to <NUM>° C and maintained for <NUM>. Then, the stirring is discontinued, the solid product was allowed to settle and the supernatant liquid is siphoned off. Then <NUM> of fresh TiCl<NUM> are added. The mixture is reacted at <NUM>° C for <NUM> and, then, the supernatant liquid is siphoned off. The solid is washed six times with anhydrous hexane (<NUM>×<NUM>) at <NUM>° C.

The solid catalyst component described above was contacted at <NUM>° C for <NUM> minutes with aluminium triethyl (TEAL) and dicyclopentyldimethoxysilane (DCPMS) as outside-electron-donor component. The weight ratio between TEAL and the solid catalyst component and the weight ratio between TEAL and DCPMS are specified in Table <NUM>.

The catalyst system is then subjected to prepolymerization by maintaining it in suspension in liquid propylene at <NUM>° C for about <NUM> minutes before introducing it into the first polymerization reactor.

The polymerisation run is conducted in continuous in a series of two reactors equipped with devices to transfer the product from one reactor to the one immediately next to it. The first reactor is a gas-phase polymerization reactor having two interconnected polymerization zones. (riser and downer) as described in the European patent <CIT>. The second reactor is a fluidized bed gas phase reactors. Polymer (a) is prepared in the first reactor, while polymer (b) is prepared in the second reactor, respectively.

Temperature and pressure are maintained constant throughout the course of the reaction. Hydrogen is used as molecular weight regulator.

The gas phase (propylene, ethylene and hydrogen) is continuously analysed via gas-chromatography.

At the end of the run the powder is discharged and dried under a nitrogen flow.

Then the polymer particles of the heterophasic composition are introduced in a twin screw extruder (Werner-type extruder), wherein they are mixed with <NUM>% wt (based on the total amount of polyolefins) of QCP5603 ivory (a r-PE commercialized by Lyondellbasell containing <NUM>%wt of PP inclusions) and a standard stabilization package. The polymer particles are extruded under nitrogen atmosphere in a twin screw extruder, at a rotation speed of <NUM> rpm and a melt temperature of <NUM>-<NUM>° C.

Example <NUM> was repeated under the conditions specified in Table <NUM>, except that the heterophasic composition was mechanically blended <NUM>%wt of Hostalen GF4750 a virgin HDPE commercialized by Lyondellbasell.

The polymer composition used in this example is a market reference having the same structure (a)/(b)/(c), and substantially the same composition, of example <NUM> with the difference that the component (c) has been introduced via sequential polymerization in agreement with the disclosure of <CIT>.

Claim 1:
A polypropylene composition comprising (percentage by weight unless otherwise specified):
(a) <NUM> to <NUM>%, of a crystalline propylene polymer having an amount of isotactic pentads (mmmm), measured by <NUM>C-MNR on the fraction insoluble in xylene at <NUM>° C, higher than <NUM> molar% and a polydispersity index ranging from <NUM> to <NUM>;
(b) <NUM> to <NUM>% of an elastomeric copolymer of ethylene and propylene, the copolymer having an amount of recurring units deriving from ethylene ranging from <NUM> to <NUM>%, and being partially soluble in xylene at ambient temperature; the polymer fraction soluble in xylene at ambient temperature having an intrinsic viscosity value ranging from <NUM> to <NUM> dl/g; and
(c) <NUM> to <NUM>% of recycled polyethylene (r-PE) having a melt flow rate (<NUM>/<NUM>) from <NUM> to <NUM>/<NUM>' and containing an amount of polypropylene inclusions ranging from <NUM> to <NUM>%wt of the total r-PE component,
the whole polypropylene composition having a value of melt flow rate (ISO <NUM><NUM>/<NUM>) ranging from <NUM> to <NUM>/<NUM>; the percentages of (a), (b) and (c) being referred to the sum of (a), (b) and (c).