CN119731260A

CN119731260A - Polyolefin compositions obtained from recycled polyolefin

Info

Publication number: CN119731260A
Application number: CN202380060555.2A
Authority: CN
Inventors: S·斯巴塔罗; D·塔尔塔里; C·科瓦; C·卡瓦列里
Original assignee: Basell Poliolefine Italia SRL
Current assignee: Basell Poliolefine Italia SRL
Priority date: 2022-09-14
Filing date: 2023-08-21
Publication date: 2025-03-28
Also published as: WO2024056321A1; EP4587515A1

Abstract

一种聚丙烯组合物，包括：(a)从45.7重量％至69.7重量％的结晶丙烯聚合物；(b)从5.3重量％至29.3重量％的乙烯和丙烯的弹性体共聚物；(c)从3.0重量％至27.0重量％的再循环聚乙烯(r‑PE)；d)从1.0重量％至15.0重量％的结晶丙烯均聚物；(a)、(b)、(c)和(d)的百分比是相对于(a)、(b)、(c)和(d)的总和。A polypropylene composition comprising: (a) from 45.7 wt% to 69.7 wt% of a crystalline propylene polymer; (b) from 5.3 wt% to 29.3 wt% of an elastomeric copolymer of ethylene and propylene; (c) from 3.0 wt% to 27.0 wt% of recycled polyethylene (r-PE); d) from 1.0 wt% to 15.0 wt% of a crystalline propylene homopolymer; the percentages of (a), (b), (c) and (d) are relative to the sum of (a), (b), (c) and (d).

Description

Polyolefin compositions obtained from recycled polyolefin

Technical Field

The present disclosure relates to polyolefin compositions containing recycled polyethylene, which are useful in injection molded articles, particularly for grills and pails.

Background

In WO2006/125720 a polyolefin composition for this purpose is described, which is made from a) 65% to 77%, preferably 70% to 77%, of a crystalline propylene polymer having an isotactic pentad (mmmm) in an amount of more than 97.5 mol% measured by 13C-MNR on a fraction insoluble in xylene at 25 ℃ and a polydispersity index ranging from 5 to 10, b) 8% to less than 13%, preferably 9% to 12%, of an elastomeric copolymer of ethylene and propylene having recurring units derived from ethylene in an amount ranging from 30% to 70%, preferably 35% to 60%, and being partly soluble in xylene at ambient temperature, and C) 10% to 23%, preferably 10% to 20%, of a polyethylene having an intrinsic viscosity value ranging from 1.5dl/g to 4dl/g and optionally containing recurring units derived from 10% in an amount of propylene.

Polyolefin compositions suitable for these applications have good rigidity, impact resistance and stress whitening resistance.

In general, polyolefin compositions, while being appreciated in terms of performance, are of interest in terms of sustainability, particularly with reference to the fact that their production is based on the use of non-renewable resources.

Thus, a common attempt to alleviate this problem is to use variable amounts of recycled polyolefin, such as polypropylene or polyethylene, in multicomponent polyolefin compositions.

Recycled polyolefins are derived from Post Consumer Waste (PCW) material streams that are separated from other polymers such as PVC, PET or PS through various steps.

In polyolefin recycling, particularly when processing material streams from Post Consumer Waste (PCW), one of the key problems is the difficulty in quantitatively separating polypropylene (PP) from Polyethylene (PE) and vice versa. Thus, despite being referred to as recycled PE (rPE) or recycled PP (rPP), commercial products from PCW sources have been found to be mixtures of PP and PE in various amounts.

This fact is associated with the presence of additives and minor components in the recycled material that may not be perfectly suited to the applications in which they are supposed to be used, leading to such recycled PP/PE blends suffering from deterioration of mechanical and optical properties during remodeling and poor compatibility between the major polymer phases. As a result, the reliability of the articles using r-PP or r-PE is considered to be lower because of the lower performance of the compositions used for these articles.

Thus, the use of recycled materials in applications requiring high performance levels is highly discouraged and limited to low cost and less demanding applications.

It has now been unexpectedly found that in certain polypropylene compositions for water management systems, the presence of recycled PE components does not impair performance and makes their production process more sustainable.

Disclosure of Invention

Accordingly, an object of the present disclosure is a polypropylene composition comprising:

(a) From 45.7 to 69.7 wt%, preferably from 47.7 to 67.7 wt%, more preferably from 50.7 to 64.7 wt% of a crystalline propylene polymer having an isotactic pentad (mmmm) measured by ¹³ C-MNR on a fraction insoluble in xylene at 25 ℃ in an amount of more than 97.0 mole% and a polydispersity index ranging from 3 to 15;

(b) From 5.3 to 29.3 wt%, preferably from 7.3 to 27.3 wt%, more preferably from 10.3 to 24.3 wt% of an elastomeric copolymer of ethylene and propylene having repeat units derived from ethylene in an amount ranging from 30.0 to 70.0 wt%, preferably from 35.0 to 60.0 wt%, more preferably from 40.0 to 53.0 wt%, as measured by ¹³ C-MNR;

Wherein in the blend of components a) and b):

i) Component a) +b) ranges from 10.0 wt.% to 32.5 wt.%, preferably from 14.0 wt.% to 28.2 wt.%, more preferably from 17.0 wt.% to 25.1 wt.% of the polymer fraction soluble in xylene at 25 ℃;

ii) component a) +b) the polymer fraction soluble in xylene at 25 ℃ has an intrinsic viscosity value ranging from 1.5dl/g to 2.8dl/g, preferably ranging from 1.7dl/g to 2.7dl/g, more preferably ranging from 1.8dl/g to 2.6dl/g, measured in tetrahydronaphthalene at 135 ℃;

iii) The ethylene derived unit content of components a) +b, measured by ¹³ C-MNR, in the fraction soluble in xylene at 25 ℃ ranges from 24.4 wt.% to 43.5 wt.%, preferably ranges from 29.0 wt.% to 40.0 wt.%, more preferably ranges from 32.0 wt.% to 39.0 wt.%;

iv) the melting point of components a) +b, measured by DSC, ranges from 148.0 ℃ to 168.0 ℃, preferably ranges from 154.0 ℃ to 167.0 ℃, more preferably ranges from 162.0 ℃ to 166.0 ℃;

v) the melt flow rate (ISO 1133-1230 ℃ C./2.16 kg) of components a) +b ranges from 10.0g/10min to 30.0g/10min, preferably ranges from 13.0g/10min to 25.0g/10min, more preferably ranges from 16.0g/10min to 22.0g/10min;

The polypropylene composition further comprises:

(c) From 3.0 to 27.0 wt%, preferably from 5.0 to 25.0 wt%, more preferably from 7.0 to 23.0 wt% of recycled polyethylene (r-PE) having a melt flow rate (ISO 1133-1190 ℃ C./2.16 Kg) from 0.1g/10min to 10.0g/10min and containing polypropylene content in an amount ranging from 1 to 15wt% of the total r-PE component,

D) From 1.0 wt% to 15.0 wt%, preferably from 5.0 wt% to 13.0 wt%, more preferably from 7.0 wt% to 12.0 wt% of a crystalline propylene homopolymer having a melt flow rate (ISO 1133-1230 ℃ C./2.16 kg), preferably ranging from 1.0g/10min to 5.0g/10min, more preferably ranging from 1.5g/10min to 3.0g/10min, and a density (ISO 1183-1) ranging from 0.850g/cm ³ to 0.950g/cm ³, preferably from 0.870g/cm ³ to 0.930g/cm ³, more preferably from 0.890g/cm ³ to 0.910g/cm ³;

The overall composition has a melt flow rate (ISO 1133-1230 ℃ C./2.16 kg) value ranging from 3.0g/10min to 21.0g/10min, preferably from 4.3g/10min to 18.0g/10min, more preferably from 9.0g/10min to 16.0g/10 min;

The percentages of (a), (b), (c) and (d) are relative to the sum of (a), (b), (c) and (d).

Detailed Description

The term "copolymer" as used herein refers to polymers having two different repeat units in the chain and polymers having more than two different repeat units, such as terpolymers. By "ambient temperature" is meant herein a temperature of 25 ℃ (room temperature).

The term "crystalline propylene polymer" in the present application means a propylene polymer having an amount of isotactic pentads (mmmm) measured by 13C-MNR on a fraction insoluble in xylene at 25 ℃, higher than 70% by weight in xylene at ambient temperature, and an "elastomeric" polymer means a polymer having a solubility in xylene higher than 50% by weight.

All features of the copolymers (a) to (d) are not inseparably connected to one another. This means that the preferences of a particular level of one of these features do not necessarily relate to the preferences of the same level of the remaining features.

The crystalline propylene polymer (a) is selected from propylene homopolymers and propylene copolymers containing up to 3.0 wt% of ethylene or C4-C10 alpha-olefins or combinations thereof. Propylene homopolymers are particularly preferred.

Preferably, the polydispersity index ranges from 3 to 10.

The r-PE (c) is a crystalline or semi-crystalline high density PE (r-HDPE) selected from commercial PCWs (e.g., post-consumer waste from municipalities). Preferably, r-PE (C) has a density (ISO 1183-1) ranging from 0.940g/cm ³ to 0.965g/cm ³ and a melt flow rate (ISO 1133-1190 ℃ C./2.16 Kg ISO 1133-1) ranging from 0.1g/10min to 1.0g/10 min.

Prior to its use, the plastic mixture containing rHDPE is subjected to standard recycling processes, including collection, shredding, sorting and washing. Although the sorted rHDPE consisted of a large amount of HDPE, it always contained small amounts of other polymers and/or inorganic components. In particular, the r-PE according to the present disclosure contains polypropylene content in an amount of from 1.0 wt% to 15 wt%, preferably from 5 wt% to at most 10 wt%, of the total r-PE component.

In a preferred embodiment, the r-PE comprises a crystalline polyethylene fraction wherein the amount of propylene-derived repeat units in the polyethylene chain is below 11 wt.%, and most preferably they are absent, i.e. most preferably the r-PE is an ethylene homopolymer containing the above-mentioned inclusions. Preferably, (r-PE) has a melt flow rate (ISO 1133-1190 ℃ C./2.16 Kg ISO 1133-1) from 0.1g/10min to 1.0g/10min, and more preferably from 0.1g/10min to 0.5g/10 min.

R-PE is commercially available. Examples of suitable r-PE grades are represented by grade Lyondellbasell sold under the trade name Hostalen QCP5603 as ivory or gray version.

The compositions of the present disclosure preferably exhibit a tensile modulus value of at least 1000MPa, preferably from 1050MPa to 1700MPa, even more preferably from 1100MPa to 1600 MPa.

The Charpy impact resistance at 23℃is preferably higher than 10.0kJ/m ², preferably ranging from 10.5kJ/m ² to 18.0kJ/m ², more preferably ranging from 11.0kJ/m ² to 17.0kJ/m ², the Charpy impact resistance at 0℃is preferably higher than 6.0kJ/m ², preferably ranging from 6.5kJ/m ² to 12.0kJ/m ², more preferably ranging from 7.0kJ/m ² to 10.0kJ/m ², and the Charpy impact resistance at-20℃is preferably at least 4.0kJ/m ², preferably ranging from 4.5kJ/m ² to 10.0kJ/m ².

Component d) is a propylene homopolymer which can be obtained according to procedures known in the art. In particular, component d) may be a commercial product, such as AdstifHA H sold by Lyondellbasell.

The compositions of the present disclosure may be obtained by mechanically blending components (a) to (d) according to conventional techniques.

According to a preferred method of preparation, components (c) and (d) are mechanically blended with a preformed multiphase composition comprising components (a) and (b) that are associated together by a sequential copolymerization process.

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

i) A solid catalyst component comprising Ti, mg, cl and at least one internal electron donor compound;

ii) an alkyl aluminum compound and,

Iii) An external electron donor compound having the general formula:

(R ⁷)_a(R⁸)_bSi(OR⁹)_c, wherein a and b are integers from 0 to 2, c is an integer from 1 to 4, and the sum of (a+b+c) is 4;R ⁷、R⁸ and R ⁹ is an alkyl, cycloalkyl or aryl radical having 1 to 18 carbon atoms optionally containing heteroatoms.

The internal donor is preferably selected from esters of mono-or dicarboxylic acid organic acids, such as benzoates, malonates, phthalates and certain succinates. Examples of internal donors are described in US 4522930A, EP 045977A2 and International patent applications WO 00/63261 and WO 01/57099. Particularly suitable are phthalates and succinates. Alkyl phthalates are preferred, such as diisobutyl phthalate, dioctyl phthalate and diphenyl phthalate, and benzyl butyl phthalate.

The particles of solid component (i) may have a substantially spherical morphology and an average diameter ranging between 5 μm and 150 μm, preferably from 20 μm to 100 μm, and more preferably from 30 μm to 90 μm. By particles having a substantially spherical morphology, it is meant those particles in which the ratio between the larger axis and the smaller axis is equal to or lower than 1.5, and preferably lower than 1.3.

The amount of Mg may preferably range from 8% to 30%, more preferably from 10% to 25% by weight.

The amount of Ti may range from 0.5 wt% to 7 wt%, and more preferably from 0.7 wt% to 5 wt%.

According to one method, the solid catalyst component (i) can be prepared by reacting a titanium compound of formula Ti (OR) q-yXy, wherein q is the valence of titanium and y is a number between 1 and q, preferably TiCl4, with magnesium chloride derived from an adduct of formula mgcl2·proh, wherein p is a number between 0.1 and 6, preferably from 2 to 3.5, and R is a hydrocarbyl radical having 1 to 18 carbon atoms. The adducts may be suitably prepared in spherical form by mixing an alcohol and magnesium chloride, operating under stirring at the melting temperature of the adduct (100 ℃ to 130 ℃). The adduct is then mixed with an inert hydrocarbon which is immiscible with the adduct, thereby creating an emulsion which is rapidly quenched, causing the adduct to solidify in the form of spherical particles. Examples of spherical adducts prepared according to this procedure are described in USP4,399,054 and USP4,469,648. The adduct thus obtained may be directly reacted with the Ti compound or it may be subjected to a thermally controlled dealcoholation (80 ℃ to 130 ℃) beforehand, to obtain an adduct in which the number of moles of alcohol is 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 TiCl4, heating the mixture to 80 to 130 ℃ and maintaining it at this temperature for 0.5 to 2 hours. The treatment with TiCl4 can be carried out one or more times. The electron donor compound can be added in the desired ratio during the treatment with TiCl 4.

The alkyl-Al compound (ii) is preferably selected from trialkylaluminum 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 Al2Et3Cl3, possibly mixed with the trialkylaluminums described above. The Al/Ti ratio is higher than 1 and may preferably be in the range between 50 and 2000.

Particularly preferred are silicon compounds (iii) wherein a is 1, b is 1, C is 2, at least one of R7 and R8 is selected from branched alkyl, cycloalkyl or aryl groups having 3 to 10 carbon atoms, optionally containing heteroatoms, and R9 is a C1-C10 alkyl group, in particular methyl. Examples of such preferred silicon compounds are methylcyclohexyldimethoxy silane (C donor), diphenyldimethoxy silane, methyl tert-butyldimethoxy silane, dicyclopentyldimethoxy silane (D donor), diisopropyldimethoxy silane, (2-ethylpiperidinyl) tert-butyldimethoxy silane, (2-ethylpiperidinyl) tert-hexyldimethoxy silane, (3, 3-trifluoro-n-propyl) (2-ethylpiperidinyl) dimethoxy silane, methyl (3, 3-trifluoro-n-propyl) dimethoxy silane. Furthermore, also preferred are silicon compounds wherein a is 0, c is 3, R8 is a branched alkyl or cycloalkyl group optionally containing heteroatoms and R9 is methyl. Examples of such preferred silicon compounds are cyclohexyltrimethoxysilane, t-butyltrimethoxysilane and t-hexyltrimethoxysilane.

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

The polymerization process may be carried out in the gas phase, operated in one or more fluidized bed or mechanically stirred bed reactors, slurry polymerization using an inert hydrocarbon solvent as diluent, or bulk polymerization using a liquid monomer (e.g., propylene) as reaction medium.

Preferably, the heterophasic composition used in the present disclosure is obtained by a sequential polymerization process in two or more stages, wherein component (a) is obtained in a first stage and component (b) is then obtained in a second stage in the presence of component (a). Each stage may be carried out in the gas phase, operated in one or more fluidized bed or mechanically stirred bed reactors, or bulk polymerization using liquid monomer (e.g. propylene) as the reaction medium. Also preferred is a mixing process, wherein one stage (preferably the stage of preparing component (a)) is carried out in liquid monomer and the other stage (preferably the stage of preparing component (b)) is carried out in gas phase.

According to a preferred embodiment, component (a) is prepared in a gas phase reactor comprising first and second interconnected polymerization zones, into which propylene and optionally ethylene are fed in the presence of a catalyst system, and from which the produced polymer is withdrawn, as described in EP 782587. The growing polymer particles flow through a first of said polymerization zones (riser) under fast fluidization conditions, leave said first polymerization zone and enter a second of said polymerization zones (downcomer), through which they flow in densified form under the action of gravity, leave said second polymerization zone and are reintroduced into said first polymerization zone, thus establishing a polymer circulation between the two polymerization zones. Typically, the fast fluidization conditions in the first polymerization zone are established by feeding the monomer gas mixture below the point at which the growing polymer is reintroduced into the first polymerization zone. The rate of the transfer gas into the first polymerization zone is higher than the transfer rate under operating conditions and is typically between 2m/s and 15 m/s. In the second polymerization zone, in which the polymer flows in densified form under the action of gravity, a high solids density value is reached which approximates the bulk density of the polymer, so that a positive pressure gain can be obtained along the flow direction, so that the polymer can be reintroduced into the first reaction zone without the aid of mechanical means. In this way, a "loop" circulation is established, which is defined by the pressure balance between the two polymerization zones and the head loss introduced into the system. Optionally, one or more inert gases, such as nitrogen or aliphatic hydrocarbons, are maintained in the polymerization zone in an amount such that the sum of the partial pressures of the inert gases is preferably between 5% and 80% of the total pressure of the gases. Preferably, the various catalyst components are fed to the first polymerization zone at any point in the first polymerization zone. However, they may also be fed at any point in the second polymerization zone. Molecular weight regulators known in the art (particularly hydrogen) may be used to regulate the molecular weight of the growing polymer. If a bimodal arrangement is desired, a barrier flow separating the polymerization environment of the riser and the downcomer as described in EP-A-1012195 may be used.

The polymerization may be carried out at a temperature of from 20 ℃ to 120 ℃, preferably from 40 ℃ to 80 ℃. When the polymerization is carried out in the gas phase, the operating pressure may range between 0.5MPa and 5MPa, preferably between 1MPa and 4 MPa. In bulk polymerization, the operating pressure may range between 1MPa and 8MPa, preferably between 1.5MPa and 5 MPa. Hydrogen can be used as a molecular weight regulator.

If desired, the final heterophasic composition comprising (a) + (b) may be chemically treated with an organic peroxide to reduce the average molecular weight and increase the melt flow index to the value required for the specific application.

The final composition comprising components (a) to (d) may be added together with conventional additives, fillers and pigments commonly used in olefin polymers, such as nucleating agents, extender 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 improves some mechanical properties, such as flexural modulus and HDT. Talc may also have a nucleating effect.

For example, the nucleating agent is added to the compositions of the present disclosure in an amount ranging from 0.05 wt% to 2wt%, more preferably from 0.1wt% to 1wt%, relative to the total weight.

The polypropylene composition objects of the present disclosure may be used to obtain injection molded articles of various objects. Particularly preferred is the use of the polypropylene composition for the preparation of automotive battery cases.

As shown in the examples below, compositions employing r-PE do not exhibit any deterioration in properties relative to compositions employing virgin PE having similar characteristics.

The following examples are given for the purpose of illustration and not limitation of the present disclosure.

Examples

Characterization of

Xylene Soluble (XS) fraction at 25 °c

2.5G of polymer and 250ml of xylene were introduced into a glass flask equipped with a refrigerator and a magnetic stirrer. The temperature was raised to the boiling point of the solvent in 30 minutes. The resulting clear solution was then kept at reflux and stirred for 30 minutes. The closed flask was then kept in an ice-water bath for 30 minutes, then in a thermostatic water bath at 25 ℃ for 30 minutes. The resulting solid was filtered on a quick filter paper. 100ml of the filtrate was poured into a pre-weighed aluminum container, which was heated on a heating plate under a nitrogen flow to remove the solvent by evaporation. The vessel was then kept in an oven at 80 ℃ under vacuum until a constant weight was reached. The weight percent of polymer soluble in xylene at room temperature was then calculated.

The content of the xylene soluble fraction is expressed as a percentage of the original 2.5 grams and then expressed by the difference (supplemented to 100%) as the xylene insoluble percentage (%);

melt Flow Rate (MFR)

Measured according to ISO 1133-1 at 230 ℃ and under a load of 2.16kg, unless specified otherwise.

Density of

Measured according to ISO 1183-1.

Intrinsic Viscosity (IV)

The sample was dissolved in tetrahydronaphthalene at 135 ℃ and then poured into a capillary viscometer. The viscometer tube (Ubbelohde) is surrounded by a cylindrical glass jacket, this arrangement allowing temperature control with a circulating thermostatted liquid. The downward passage of the meniscus is timed by the electro-optical device.

The passage of the meniscus in front of the upper lamp starts a counter with a quartz crystal oscillator. The meniscus stops the counter when passing the lower lamp and the outflow time is recorded, which is converted to an intrinsic viscosity value (Huggins, m.l. "american chemical society (j.am. Chem. Soc.)), 1942,64,2716 by the hakins equation (Huggins' equation), provided that the flow time of the pure solvent under the same experimental conditions (same viscometer and same temperature) is known. A single polymer solution was used to determine [ eta ].

Polydispersity index-operating at an oscillation frequency increasing from 0.1 radians/second to 100 radians/second as measured at a temperature of 200 ℃ using a RHEOMETRICS (USA) -marketed RMS-800 parallel plate rheometer. From the cross modulus, p.i. can be derived by the following equation:

P.I.=105/Gc

Where Gc is the cross modulus, which is defined as the value (expressed in Pa) when G '=g ", where G' is the storage modulus and G" is the loss modulus.

Ethylene (C2) content

¹³ C NMR of propylene/ethylene copolymer

The 13C NMR spectrum was obtained on a BrukerAV-600 spectrometer equipped with a cryoprobe, which was operated in Fourier transform mode at 160.91MHz at 120 ℃.

Peaks of sββ carbon at 29.9ppm (according to the nomenclature of "monomer sequence distribution in ethylene-propylene rubber measured by 13C nmr.3. Use of reaction probability patterns" c.j. Carman, r.a. Harrington and c.e. wilkes, macromolecules, 1977,10,536) were used as internal references. The sample was dissolved in 1, 2-tetrachloroethane-d 2 at a concentration of 8% w/v at 120 ℃. Each spectrum was acquired with 90 ° pulses with 15 seconds delay between pulses and CPD to remove the 1H-13C coupling. 512 transient data are stored in 32K data points using the 9000Hz spectral window.

The evaluation of spectral distribution, triplet distribution, composition was performed according to Kakugo ("carbon-13 NMR determination (Carbon-13 NMR determination ofmonomer sequence distribution in ethylene-propylene copolymers preparedwithδ-titaniumtrichloride-diethylaluminum chloride)"M.Kakugo、Y.Naito、K.Mizunuma and T.Miyatake, macromolecules, 1982,15,1150) of the monomer sequence distribution in ethylene-propylene copolymers prepared from titanium-titanium trichloride-diethylaluminum chloride using the following equation:

PPP=100T_ββ/S PPE＝100T_βδ/S EPE＝100T_δδ/S

PEP=100S_ββ/S PEE＝100S_βδ/S EEE＝100(0.25S_γδ+0.5S_δδ)/S

S=T_ββ+T_βδ+T_δδ+S_ββ+S_βδ+0.25S_γδ+0.5S_δδ

the mole percent of ethylene content was evaluated using the following equation:

E% mol=100 [ pep+pee+eee ]. The weight percent of ethylene content was evaluated using the following equation:

Where pmol% is the mole percent of propylene content and MW _E and MW _P are the molecular weights of ethylene and propylene, respectively.

The product r1r2 of the reaction ratio is calculated as follows according to Carman (C.J.Carman, R.A.Harrington and C.E.Wilkes, macromolecules, 1977;10,536):

The tacticity of the propylene sequence was calculated as mm content from the ratio of PPP mmT ββ (28.90 ppm to 29.65 ppm) and full tββ (29.80 ppm to 28.37 ppm).

The 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=xb1c2b1+xb2c2b2, where Xb1 and xb2 are the amounts of components B1 and B2 in the composition.

Sample for mechanical testing

Samples were obtained according to ISO 1873-2:2007.

The Charpy impact test was determined according to ISO 179-1eA and ISO 1873-2.

Elongation at yield, measured according to ISO 527.

Elongation at break measured according to ISO 527

Breaking stress is measured according to ISO 527.

Tensile modulus measured according to ISO 527-2.

Melting Point and crystallization Point

Melting points were measured for samples weighing between 5mg and 7mg under inert N ₂ flow down at a scan rate of 20 ℃ per min under both cooling and heating using a DSC instrument according to ISO 11357-3. Instrument calibration was performed with indium.

Determination of PP content in r-PE

¹³ The C NMR spectrum was obtained on a BrukerAV-600 spectrometer equipped with a cryoprobe, which was operated in Fourier transform mode at 160.91MHz at 120 ℃.

The peak of CH ₂ ethylene was used as an internal standard at 29.9 ppm. The sample was dissolved in 1, 2-tetrachloroethane-d 2 at a concentration of 8% w/v at 120 ℃. Each spectrum was acquired with 90 ° pulses with 15 seconds delay between pulses and the ¹H-¹³ C coupling was removed with CPD. 512 transient data are stored in 32K data points using the 9000Hz spectral window.

The molar composition was obtained according to the following using peak areas (table 1):

P=100A₃/S

E=1000.5A₂/S

Wherein s=0.5A ₂+A₃

The molar content is converted to weight using the molecular weight of the monomer.

TABLE A partitioning of PP/PE mixtures

Examples

Example 1

In a plant operating continuously according to the mixed liquid-gas polymerization technique, the operation was carried out under the conditions specified in table 1.

The polymerization is carried out in the presence of a catalyst system in a series of two reactors equipped with means for transferring the product from one reactor to the one immediately adjacent thereto.

Preparation of solid catalyst component

250Ml of TiCl ₄ were introduced into a 500ml four-necked round bottom flask purged with nitrogen at 0 ℃. While stirring, 10.0g of microspheroidal MgCl ₂·1.9C₂H₅ OH (prepared according to the procedure described in example 2 of U.S. Pat. No. 4,399,054, but operating at 3000rpm instead of 10000 rpm) and 9.1mmol of diethyl 2,3- (diisopropyl) succinate were added. The temperature was raised to 100 ℃ and maintained for 120 minutes. The stirring was then stopped, the solid product was allowed to settle and the supernatant was siphoned off. Then 250ml of fresh TiCl ₄ are added. The mixture was allowed to react at 120 ℃ for 60 minutes, then the supernatant was siphoned off. The solid was washed six times with anhydrous hexane (6X 100 ml) at 60 ℃.

Catalyst system and prepolymerization treatment

The solid catalyst component described above was contacted with Triethylaluminum (TEAL) and dicyclopentyl dimethoxy silane (DCPMS) as external electron donor components at 12 ℃ for 24 minutes. The weight ratio between TEAL and the solid catalyst component and the weight ratio between TEAL and DCPMS are specified in table 1.

The catalyst system was then subjected to prepolymerization by maintaining it in suspension in liquid propylene at 20℃for about 5 minutes, after which it was introduced into the first polymerization reactor.

Polymeric components a) and b)

The polymerization run was carried out continuously in a series of two reactors equipped with means to transfer the product from one reactor to the one immediately adjacent thereto. As described in european patent EP 782587, the first reactor is a gas phase polymerization reactor having two interconnected polymerization zones (riser and downcomer). The second reactor is a fluidized bed gas phase reactor. Separately, polymer (a) is prepared in a first reactor and polymer (b) is prepared in a second reactor. The temperature and pressure were maintained constant throughout the reaction. Hydrogen is used as a molecular weight regulator.

The gas phases (propylene, ethylene and hydrogen) were analyzed continuously via gas chromatography.

At the end of the run, the powder was discharged and dried under a nitrogen stream. The polymerization parameters are reported in Table 1

TABLE 1 polymerization process

The polymer pellets of the heterophasic compositions of example 1 and comparative example 2 were then introduced into a twin screw extruder (Werner type extruder) where they were mixed with 10 wt% and 15 wt% (based on the total polyolefin) of QCP5603 ivory (r-PE commercialized by Lyondellbasell, which contains 10 wt% PP content) and a standard stabilizing bag. The polymer pellets were extruded in a twin screw extruder under nitrogen atmosphere at a speed of 250rpm and a melt temperature of 200 ℃ to 250 ℃.

TABLE 2 characterization

The properties of the final composition are reported in table 3.

TABLE 3 Properties of the final composition

The above data shows that the polymer compositions according to the present disclosure show better impact properties relative to the comparative examples.

Claims

1. A polypropylene composition comprising:

(a) From 45.7 to 69.7 wt% of a crystalline propylene polymer having an isotactic pentad (mmmm) in an amount of more than 97.0 mole% measured by ¹³ C-MNR on a fraction insoluble in xylene at 25 ℃ and a polydispersity index ranging from 3 to 15;

(b) From 5.3 to 29.3 weight percent of an elastomeric copolymer of ethylene and propylene, the copolymer having repeat units derived from ethylene in an amount ranging from 30.0 to 70 weight percent as measured by ¹³ C-MNR;

Wherein in the blend of components a) and b):

i) Component a) +b) ranges from 10.0 to 32.5 wt% of the polymer fraction soluble in xylene at 25 ℃;

ii) component a) +b) said polymer fraction soluble in xylene at 25 ℃ has an intrinsic viscosity value ranging from 1.5dl/g to 2.8dl/g measured in tetrahydronaphthalene at 135 ℃;

iii) The content of ethylene derived units in the fraction soluble in xylene at 25 ℃ measured by ¹³ C-MNR ranges from 24.4 wt% to 43.5 wt%;

iv) a melting point as measured by DSC ranging from 148.0 ℃ to 168.0 ℃;

v) melt flow rate (ISO 1133-1230 ℃ C./2.16 kg) ranging from 10.0g/10min to 30.0g/10min;

The polypropylene composition further comprises:

(c) From 3.0 wt% to 27.0 wt% recycled polyethylene (r-PE) having a melt flow rate (ISO 1133-1190 ℃ per 2.16 Kg) from 0.1g/10min to 10g/10min and containing polypropylene content in an amount ranging from 1 wt% to 15 wt% of the total r-PE component;

d) From 1.0 wt% to 15.0 wt% of a crystalline propylene homopolymer having a melt flow rate (ISO 1133-1230 ℃ C./2.16 kg) ranging from 0.3g/10min to 10.0g/10min, and a density (ISO 1183-1) ranging from 0.850g/cm ³ to 0.950g/cm ³;

The overall composition has a melt flow rate (ISO 1133-1230 ℃ C./2.16 kg) value ranging from 3.0g/10min to 21.0g/10 min;

2. The polypropylene composition according to claim 1, wherein:

component (a) ranges from 47.7 wt% to 67.7 wt%;

Component (b) ranges from 7.3 wt% to 27.3 wt%;

Component (c) ranges from 5.0 wt% to 25.0 wt%;

Component (d) ranges from 5.0 wt% to 13.0 wt%.

3. Polypropylene composition according to claim 2, wherein component a) +b) is soluble in xylene at 25 ℃ in the range of from 14.0 to 28.2 wt%.

4. A polypropylene composition according to any one of claims 1 to 3 having a melt flow rate (ISO 1133-1230 ℃ per 2.16 kg) ranging from 4.3g/10min to 18.0g/10 min.

5. The polypropylene composition according to any one of claims 1 to 4, wherein component (c) has PP inclusions in an amount ranging from 5 to 10 wt. -%, based on the total amount of component (c).

6. The polypropylene composition according to any one of claims 1 to 5, wherein component (C) has a density (ISO 1183-1) ranging from 0.940g/cm ³ to 0.965g/cm ³ and a melt flow rate (ISO 1133-1190 ℃ per 2.16kg ISO 1133-1) from 0.1g/10min to 1.0g/10 min.

7. The polypropylene composition according to any one of claims 1 to 6, wherein component a) +b) the polymer fraction soluble in xylene at 25 ℃ has an intrinsic viscosity value ranging from 1.7dl/g to 2.7dl/g measured in tetrahydronaphthalene at 135 ℃.

8. The polypropylene composition according to any one of claims 1 to 7, wherein the ethylene derived unit content in the fraction soluble in xylene at 25 ℃ of components a) +b) measured by ¹³ C-MNR ranges from 31.0 to 42.0 wt%.

9. The polypropylene composition according to any one of claims 1 to 8, wherein component (b) has ethylene in an amount ranging from 35.0 to 60.0 wt% as measured by ¹³ C-MNR.

10. The polypropylene composition according to any one of claims 1 to 9, wherein the intrinsic viscosity of the xylene soluble fraction of component a) +b) at 25 ℃ measured in tetrahydronaphthalene at 135 ℃ ranges from 1.7dl/g to 2.7dl/g.

11. Polypropylene composition according to any one of claims 1 to 10, wherein the melting point of components a) +b, measured by DSC, ranges from 154.0 ℃ to 167.0 ℃.

12. The polypropylene composition according to any one of claims 1 to 11, wherein component d) has a melt flow rate (ISO 1133-1230 ℃ per 2.16 kg) ranging from 1.0g/10min to 5.0g/10 min.

13. The polypropylene composition according to any one of claims 1 to 12, wherein component d) has a density (ISO 1183-1) ranging from 0.870g/cm ³ to 0.930g/cm ³.

14. Injection molded article made from the composition of claims 1 to 13.

15. The injection molded article of claim 14 in the form of an automotive battery compartment.