Polyolefin composition containing regenerated material

Abstract

A polyolefin composition (I) comprising: (A) from 70% to 97% by weight of a polypropylene composition comprising:-from 20% to 45% by weight of a polymer fraction (a) comprising a propylene homopolymer, a propylene copolymer or a combination thereof and having a solubility in xylene equal to or lower than 10% by weight; and-from 55% to 80% by weight of a polymer fraction (b) comprising a copolymer of ethylene with propylene, an alpha-olefin of CH2 = CHR type or a combination thereof, the copolymer containing greater than 50.0% by weight of ethylene units and having a solubility in xylene of equal to or greater than 60% by weight, and (B) from 3% to 30% by weight of a regenerated styrene block copolymer (rSBC), the regenerated styrene block copolymer has a melt flow rate of from 2.0 to 15.0 g / 10 min, and an article, preferably a film or sheet, made therefrom.

Description

Technical Field

[0001] The present disclosure relates to a polyolefin composition containing a recycled elastomeric material (especially a recycled styrene block copolymer), which is suitable for producing soft articles, especially artificial leather for automotive interiors. Background Art

[0002] Soft polypropylene compositions having good elastic properties and maintaining good thermoplastic behavior are known in the art and can be conveniently prepared by sequential copolymerization of propylene, optionally containing a small amount of an olefin comonomer, followed by a mixture of ethylene / propylene or ethylene / α-olefin copolymers. Catalysts based on titanium halide compounds supported on magnesium chloride are commonly used for this purpose.

[0003] For example, EP0400333A2 discloses an elastoplastic composition comprising: 10 to 60 parts by weight of a propylene homopolymer or copolymer; 10 to 40 parts by weight of a polymer fraction containing ethylene and insoluble in xylene; and 30 to 60 parts by weight of an amorphous ethylene-propylene copolymer fraction soluble in xylene at room temperature and containing 40 to 70% by weight of ethylene-derived units. These compositions have flexibility as well as good tensile and thermal properties, however such values are not entirely satisfactory for some applications, especially for manufacturing extruded parts for automotive interiors (such as artificial leather), which require reduced stickiness while maintaining a soft touch and good mechanical properties.

[0004] Blends of polypropylene multiphase compositions and elastomers (such as styrene block copolymers) are also known in the art, for example with reference to WO2004 / 026956. These compositions are known to have softness and good abrasion resistance and can be conveniently used for producing injection-molded or extruded articles such as floor mats, hoses, handles, and grips for the automotive field.

[0005] In recent years, automotive manufacturers have been committed to reducing the use of virgin plastics in the vehicles they produce, thus increasing the demand for plastic materials containing recycled plastics.

[0006] Blends of virgin polypropylene multiphase compositions with different amounts of recycled plastics are known in the art.

[0007] WO2007 / 071494 describes a blend consisting of 20% to 70% by weight of a virgin polyolefin composition (bending modulus equal to or lower than 600 MPa) and 30% to 80% by weight of a polyolefin component (containing no less than 80% by weight of waste materials selected from polyethylene, polypropylene, and mixtures thereof), said blend having satisfactory elongation at break and yield strength, especially when the virgin polyolefin contains an elastomeric component with an ethylene content of 45% to 90% by weight.

[0008] In this context, it has been found that by blending a polypropylene composition containing an ethylene-rich elastomeric component with a specific recycled elastomeric material, a polyolefin composition with improved performance characteristics can be prepared. Summary of the Invention

[0009] The present disclosure relates to a polyolefin composition (I) comprising:

[0010] (A) 70% to 97% by weight of a polypropylene composition, which polypropylene composition comprises:

[0011] - 20% to 45% by weight of a polymer fraction (a), which polymer fraction (a) comprises a propylene polymer selected from propylene homopolymers, propylene copolymers, and combinations thereof, the propylene copolymer containing, based on the weight of the propylene copolymer, at most and including 15.0% by weight of units derived from a comonomer selected from ethylene, CH 2 =CHR type α-olefins, where R is a linear or branched C2-C8 alkyl group,

[0012] the polymer fraction (a) has a solubility in xylene (XS(a)) at 25 °C equal to or lower than 10.0% by weight, based on the weight of the fraction (a); and

[0013] - 55% to 80% by weight of a polymer fraction (b), which polymer fraction (b) comprises a copolymer of ethylene and a comonomer selected from propylene, CH 2 =CHR type α-olefins, where R is a linear or branched C 2 - C 8 alkyl group, where the ethylene copolymer contains, based on the weight of the ethylene copolymer, more than 50.0% by weight of units derived from ethylene,

[0014] the polymer fraction (b) has a solubility in xylene (XS(b)) at 25 °C equal to or greater than 60.0% by weight, based on the weight of the fraction (b),

[0015] where the amounts of fraction (a) and fraction (b) are based on the total weight of (a)+(b), and

[0016] (B) 3% to 30% by weight of a recycled styrene block copolymer (rSBC) having a melt flow rate MFR(B) of from 2.0 to 15.0 g / 10 min (measured according to ISO 1133-1:2011 under the conditions of 230 °C / 2.16 kg),

[0017] wherein the amounts of (A) and (B) are based on the total amount of (A)+(B).

[0018] The polyolefin composition (I) of the present disclosure has a good balance of mechanical properties and thermal properties and has a good touch feeling, such as high softness and low tackiness.

[0019] The polyolefin composition (I) of the present disclosure is suitable for the production of soft articles (such as soft films or sheets), which can be conveniently used for vehicle interiors (such as artificial leather).

[0020] Therefore, another object of the present disclosure is an article comprising the polyolefin composition (I), preferably a film or a sheet.

[0021] Although multiple embodiments are disclosed, 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 can be modified in various obvious aspects without departing from the spirit and scope of the claims presented herein. Therefore, the following detailed description should be considered illustrative in nature and not restrictive. Detailed Description

[0022] In the context of the present disclosure:

[0023] - Unless otherwise specified, percentages are by weight;

[0024] - Unless otherwise specified, the total weight of the composition totals 100%;

[0025] - The term "comprising" in relation to polymers, plastic materials, polymer compositions, mixtures or blends shall be construed to mean "including or consisting essentially of". The term "consisting essentially of" means that in addition to the mandatory components, other components may also be present in the material, provided that the basic characteristics of the material are not substantially affected by their presence. Examples of components that do not substantially affect the characteristics of a polymer or a polyolefin composition, mixture or blend when present in conventional amounts are catalyst residues, antistatic agents, processing aids, melt stabilizers, light stabilizers, antioxidants and antacids;

[0026] - the term "copolymer" refers to a polymer derived from the intentional polymerization of at least two different comonomers, i.e. the term "copolymer" includes terpolymers;

[0027] - The terms "pre-consumer waste" and "post-industrial waste" are synonymous and refer to material diverted from the waste stream generated by the manufacturing process. It may be material offcuts, defective items, overstocked raw materials, excess inventory, etc.;

[0028] - The term “post-consumer waste” refers to materials discarded after use by the final consumer;

[0029] - "Film" means a thin layer of material with a thickness equal to or less than 2000 μm;

[0030] - "sheet" means a layer of material having a thickness greater than 2000 μm;

[0031] Preferably, the polyolefin composition (I) comprises:

[0032] - 75 to less than 95 wt.-%, preferably 78 to 93 wt.-%, more preferably 78 to 88 wt.-% of the polypropylene composition (A), and

[0033] - more than 5% to 25% by weight, preferably 7% to 22% by weight, more preferably 12% to 22% by weight of recycled styrene block copolymer (rSBC) (B)

[0034] The amounts of (A) and (B) are based on the total amount of (A) + (B).

[0035] In the following, the individual components of the polyolefin composition (I) are defined in more detail.The individual components may be comprised in the polyolefin composition (I) in any combination.

[0036] The polypropylene composition (A) preferably comprises:

[0037] % to 45 wt.-%, preferably 25 to 40 wt.-%, of a polymer fraction (a), which polymer fraction (a) comprises a propylene polymer selected from propylene homopolymers, propylene copolymers and combinations thereof, the propylene copolymer containing up to and including 15.0 wt.-%, preferably 0.1 to 15.0 wt.-%, more preferably 0.5 to 5.0 wt.-%, based on the weight of the propylene copolymer, of units derived from a comonomer selected from ethylene, CH 2 =CHR type α-olefin, wherein R is a linear or branched C2-C8 alkyl group,

[0038] The solubility in xylene (XS(a)) of the polymer fraction (a) at 25 °C is equal to or lower than 10.0 wt%, preferably equal to or lower than 6.0 wt%, more preferably from 0.5 wt% to 6.0 wt%, based on the weight of the fraction (a); and

[0039] - 55 wt% to 80 wt%, preferably 60 wt% to 75 wt% of the polymer fraction (b), the polymer fraction (b) comprising a copolymer of ethylene and a comonomer selected from propylene, CH 2 =CHR type α-olefin, where R is a linear or branched C 2 -C 8 alkyl group, where the ethylene copolymer contains more than 50.0 wt%, preferably 51.0 wt% to 70.0 wt%, more preferably 52.0 wt% to 65.0 wt% of units derived from ethylene, based on the weight of the ethylene copolymer,

[0040] The solubility in xylene (XS(b)) of the polymer fraction (b) at 25 °C is equal to or greater than 60.0 wt%, preferably from 60.0 wt% to 90.0 wt%, more preferably from 65.0 wt% to 85.0 wt%, still more preferably from 70.0 wt% to 80.0 wt%, based on the weight of the fraction (b),

[0041] where the amounts of fraction (a) and fraction (b) are based on the total weight of (a)+(b).

[0042] Preferably, the fraction (a) comprised in the polypropylene composition (A) has at least one, preferably all, of the following properties:

[0043] - comprises a propylene polymer selected from a propylene homopolymer, a propylene copolymer and combinations thereof, the copolymer containing at most and including 15.0 wt%, preferably 0.1 wt% to 15.0 wt%, more preferably 0.5 wt% to 5.0 wt% of units derived from a comonomer selected from ethylene, butene-1, hexene-1 and combinations thereof, particularly preferably ethylene. More preferably, fraction (a) comprises a propylene homopolymer, a propylene-ethylene copolymer or combinations thereof, the propylene-ethylene copolymer containing 0.5 wt% to 5.0 wt% of units derived from ethylene, based on the weight of the copolymer; and / or

[0044] - the melt flow rate MFR(a) (measured according to ISO 1133-1:2011, using the conditions of 260 °C / 2.16 kg) is from 2.0 to 70 g / 10 min, preferably from 5.0 to 40 g / 10 min.

[0045] Preferably, the fraction (b) contained in the polypropylene composition (A) comprises a copolymer of ethylene and a comonomer selected from propylene, butene-1, hexene-1, and combinations thereof, most preferably propylene. The copolymer contains more than 50.0% by weight, preferably 51.0% to 70.0% by weight, more preferably 52.0% to 65.0% by weight of units derived from the comonomer, preferably derived from propylene.

[0046] The polypropylene composition (A) suitable for the polyolefin composition (I) has at least one of the following properties, preferably all of the properties:

[0047] - The melt flow rate MFR(A) ranges from 0.05 to 5.0 g / 10 min, preferably from 0.1 to 3.0 g / 10 min, more preferably from 0.2 to 1.0 g / 10 min; and / or

[0048] - The intrinsic viscosity XS(A) of the fraction soluble in xylene at 25 °C is equal to or greater than 2.0 dl / g, preferably from 2.5 to 6.0 dl / g, more preferably from 3.0 to 5.0 dl / g; and / or

[0049] - The flexural modulus is equal to or lower than 600 MPa, preferably 50 to 600 MPa, more preferably 80 to 400 MPa, still more preferably 100 to 350 MPa. This property is measured on an injection-molded specimen (80 × 10 × 4 mm) obtained according to method ISO 1873-2:2007 in accordance with method ISO 178:2010.

[0050] In one embodiment, the polypropylene composition (A) further comprises up to and including 5.0% by weight, more preferably 0.01% to 5.0% by weight, of at least one additive (c) selected from the group consisting of nucleating agents, antistatic agents, antioxidants, light stabilizers, slip agents, antacids, melt stabilizers, and combinations thereof. The amount of the additive is based on the total weight of the polypropylene composition (A) containing the additive, and the total weight is 100%.

[0051] In one embodiment, the polypropylene composition (A) consists of fraction (a), fraction (b), and optionally but preferably additive (c).

[0052] The polypropylene composition (A) can be obtained by melt blending components (a), (b) and optionally (c), or preferably, the polypropylene composition (A) is a reactor blend of components (a) and (b), optionally melt blended with component (c), wherein the reactor blend is obtained by sequential polymerization of the relevant monomers in at least two, optionally but preferably at least three polymerization stages in the gas phase, wherein the second polymerization stage and each optionally subsequent optional polymerization stage are carried out in the presence of the polymer formed and the catalyst system used in the immediately preceding polymerization stage.

[0053] In a preferred embodiment, the polypropylene composition (A) is obtained by polymerizing the relevant monomers in the presence of a highly stereoselective Ziegler-Natta catalyst system, which catalyst system comprises:

[0054] (1) A solid catalyst component, which solid catalyst component comprises a magnesium halide support and a stereoregular internal donor, on which magnesium halide support there is a Ti compound having at least one Ti-halogen bond;

[0055] (2) Optionally, but preferably, an aluminum-containing cocatalyst; and

[0056] (3) Optionally, but preferably, an additional electron donor compound (external donor).

[0057] The solid catalyst component (1) preferably contains TiCl 4 , the content of which ensures that the amount of Ti present accounts for 0.5% to 10% by weight of the total weight of the solid catalyst component (1).

[0058] The solid catalyst component (1) comprises at least one stereoregular internal electron donor compound selected from monodentate or bidentate organic Lewis bases, preferably selected from esters, ketones, amines, amides, carbamates, carbonates, ethers, nitriles, alkoxysilanes and combinations thereof.

[0059] Suitable stereoregular internal donors are preferably selected from organic acid esters of monocarboxylic or dicarboxylic acids, such as benzoates, malonates, phthalates and certain succinates. Examples of internal donors are described in US4522930A, EP045977A2 and international patent applications WO00 / 63261 and WO01 / 57099. Particularly suitable are phthalates, such as diisobutyl phthalate, dioctyl phthalate and diphenyl phthalate and benzyl butyl phthalate.

[0060] The preferred magnesium halide support is magnesium dihalide.

[0061] The amount of the internal donor fixed on the solid catalyst component (1) is 5 mol% to 20 mol% relative to the magnesium dihalide.

[0062] Descriptions of the preparation of catalyst components according to general methods are found, for example, in the patents and patent applications US4,399,054, US4,469,648, WO98 / 44009A1, and EP395083A2.

[0063] According to one method, the solid catalyst component (1) can be prepared by reacting a titanium compound of the formula Ti(OR)q-yXy, where q is the valence of titanium and y is a number between 1 and q, preferably TiCl 4 ), with magnesium chloride derived from an adduct of the formula MgCl 2 ·pROH, where p is a number between 0.1 and 6, preferably between 2 and 3.5, and R is a hydrocarbon group having 1 - 18 carbon atoms. The adduct can be suitably prepared in spherical form by mixing the alcohol and magnesium chloride and 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, thus generating an emulsion that 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 USP 4,399,054 and USP 4,469,648. The adduct thus obtained can be reacted directly with the Ti compound, or it can be pre-treated by thermal controlled dealcoholation (80° - 130 °C) to obtain an adduct in which the number of moles of alcohol is less than 3, preferably between 0.1 and 2.5. The reaction with the Ti compound can preferably be carried out by suspending the adduct (dealcoholated or as such) in cold TiCl 4 ; the mixture is heated to 80° - 130 °C and maintained at this temperature for 0.5 to 2 hours. Treatment with TiCl 4 can be carried out one or more times. The internal donor compound is preferably added in the required ratio during the treatment with TiCl 4 .

[0064] The particles of the solid catalyst component (1) preferably have a substantially spherical morphology and an average diameter in the range of 5 to 150 μm, preferably 20 to 100 μm, and more preferably 30 to 90 μm. By particles having a substantially spherical morphology, it is meant that the ratio between the major axis and the minor axis is equal to or less than 1.5, and preferably less than 1.3.

[0065] The catalyst system preferably includes an Al cocatalyst (2) selected from Al-trialkyls, preferably selected from Al-triethyl, Al-triisobutyl, and Al-tri-n-butyl. The Al / Ti weight ratio in the catalyst system is from 1 to 1000, preferably from 20 to 800.

[0066] In a preferred embodiment, the catalyst system comprises an additional electron donor compound (3) (external electron donor) selected from silicon compounds, ethers, esters, amines, heterocyclic compounds (especially 2,2,6,6-tetramethylpiperidine), and ketones.

[0067] Preferred silicon compounds are selected from methylcyclohexyldimethoxysilane (C-donor), dicyclopentyldimethoxysilane (D-donor), and mixtures thereof.

[0068] The amount of the external electron donor compound (3) is such that the molar ratio between the organoaluminum compound and the external electron donor compound (3) is from 0.1 to 200, preferably from 1 to 100, and more preferably from 3 to 50.

[0069] The polymerization temperature preferably ranges from 20 °C to 100 °C, and the polymerization pressure is preferably from 0.5 to 3.0 MPa.

[0070] The molecular weight of the polymer is adjusted by feeding a molecular weight regulator (such as hydrogen) to the relevant polymerization reactor. If desired, the polypropylene composition (A) can be chemically treated with a peroxide to reduce the molecular weight and increase the final melt flow rate.

[0071] Examples of polymerization processes for preparing the composition can be found in EP472946, the relevant parts of which are incorporated herein by reference.

[0072] Preferably, fraction (a) is obtained in a first gas-phase reactor and fraction (b) is obtained in at least one second gas-phase reactor, optionally but preferably in at least two gas-phase reactors in series, in the presence of the catalyst system used in the preparation of the resulting polymer and in the immediately preceding polymerization stage. Gas-phase reactors are of types known in the art.

[0073] When the polypropylene composition (A) is a reactor blend produced by sequential polymerization in two reactors, the amounts of components (a) and (b) correspond to the distribution ratio between the two reactors. When the polypropylene composition (A) is a reactor blend produced by sequential polymerization in three reactors, the amount of fraction (a) corresponds to the distribution ratio of the first reactor relative to the total amount of polymer produced, and the amount of fraction (b) corresponds to the cumulative distribution ratio of the second and third reactors.

[0074] The recycled styrene block copolymer rSBC (B) is derived from pre-consumer waste, post-consumer waste, or a combination thereof, preferably from pre-consumer waste. In particular, the recycled styrene block copolymer rSBC (B) is derived from the mechanical recycling of at least one of the above waste streams.

[0075] Preferably, the recycled styrene block copolymer (B) comprises a block copolymer selected from the group consisting of polystyrene-polybutadiene-polystyrene (SBS), polystyrene-poly(ethylene-butylene)-polystyrene (SEBS), polystyrene-poly(ethylene-propylene)-polystyrene (SEPS), polystyrene-polyisoprene-polystyrene (SIS), polystyrene-poly(isoprene-butadiene)-polystyrene (SIBS), and mixtures thereof. More preferably, the recycled styrene block copolymer (B) comprises a polystyrene-polybutadiene-polystyrene (SBS) block copolymer.

[0076] A particularly preferred component (B) is a recycled polystyrene-polybutadiene-polystyrene block copolymer (rSBS) from pre-consumer waste, more preferably from the mechanical recycling of pre-consumer waste.

[0077] As a recycled material, the recycled styrene block copolymer (B) optionally but preferably contains up to and including 20.0 wt%, preferably 0.5 wt% to 20.0 wt%, more preferably 1.0 wt% to 15.0 wt%, still more preferably 3.0 wt% to 12.0 wt% of a material based on the weight of component (B), the material being selected from polypropylene, polyethylene, inorganic fillers (such as talc), and mixtures thereof.

[0078] Preferably, the recycled styrene block copolymer (B) has at least one, preferably all, of the following properties:

[0079] - The melt flow rate MFR(B) (measured according to ISO 1133-1:2011, using the conditions of 230 °C / 2.16 kg) ranges from 2.0 to 12.0 g / 10 min, preferably from 3.0 to 10.0 g / 10 min; and / or

[0080] - The tensile modulus ranges from 30 to 400 MPa, preferably from 100 to 350 MPa, and this property is measured on injection-molded specimens obtained according to method ISO 1873-2:2007 according to method ISO 527-3; and / or

[0081] - The Charpy impact value at 23 °C is equal to or greater than 50 kJ / m 2 , preferably equal to or greater than 60 kJ / m 2 , and this property is measured on injection-molded specimens obtained according to ISO 1873-2:2007 according to ISO179-1eA; in an embodiment, the Charpy impact value at 23 °C is 50 to 100 kJ / m 2 , more preferably 60 to 90 kJ / m 2 ; and / or

[0082] - The Charpy impact value at -20 °C is equal to or greater than 80 kJ / m 2 , preferably equal to or greater than 90 kJ / m 2 , this property is determined on injection-molded specimens obtained according to ISO 1873-2:2007 in accordance with ISO 179-1eA; in an embodiment, the Charpy impact values at -20 °C and -30 °C are 80 to 150 kJ / m 2 , more preferably 90 to 130 kJ / m 2 ; and / or

[0083] - The Vicat softening temperature is in the range of 35 °C to 95 °C, preferably 40 °C to 95 °C, more preferably 70 °C to 95 °C, still more preferably 75 °C - 90 °C, determined according to method ISO 306 (9.81 N); and / or

[0084] - The heat distortion temperature (HDT) is equal to or lower than 55 °C, more preferably equal to or lower than 50 °C, determined according to method ISO 075B (0.45 Mpa, flat, 48 h). In an embodiment, the HDT range is 30 °C to 55 °C, preferably 35 °C to 50 °C.

[0085] In one embodiment, the polyolefin composition (I) further comprises up to and including 50% by weight, preferably 0.05% to 50% by weight of component (C), which component (C) is selected from polyolefin additives, fillers, pigments, and combinations thereof, of the types commonly used in olefin polymers, such as nucleating agents, extender oils, mineral fillers, organic and inorganic pigments. In particular, the addition of mineral fillers (such as talc and calcium carbonate) or inorganic fillers also brings about some improvement in mechanical properties (such as flexural modulus and heat distortion temperature). In some embodiments, talc also has a nucleating effect.

[0086] In a preferred embodiment, component (C) is a nucleating agent, and it is added to the polyolefin composition (I) in an amount of 0.05% to 2.0% by weight, preferably 0.1% to 1.0% by weight, based on the total weight of the polyolefin composition (I).

[0087] The polyolefin composition (I) of the present disclosure is obtained by blending components (A) and (B) and optionally other components (C), preferably in the molten state, using conventional blending equipment (such as a mixer or an extruder).

[0088] Preferably, the melt flow rate MFR(I) of the polyolefin composition (I) (measured according to ISO 1133-1:2011 under the conditions of 230 °C / 2.16 kg) is from 0.1 to 5.0 g / 10 min, preferably from 0.2 to 2.0 g / 10 min, more preferably from 0.3 to 1.0 g / 10 min.

[0089] Preferably, the tensile modulus of the polyolefin composition (I) is equal to or greater than the tensile modulus of the polypropylene composition (A), and this property is measured on injection-molded specimens obtained according to ISO 1873-2:2007 in accordance with method ISO 527-3.

[0090] More preferably, the tensile modulus Tmod(I) of the polyolefin composition (I) satisfies the following equation:

[0091] Tmod(I)≥Tmod(A)W(A)+Tmod(B)W(B)

[0092] where

[0093] - Tmod(I) is the tensile modulus of the polyolefin composition (I), Tmod(A) is the tensile modulus of the polypropylene composition (A), W(A) is the relative amount of the polypropylene composition (A) in the polyolefin composition (I), Tmod(B) is the tensile modulus of the recycled styrene block copolymer (B), and W(B) is the relative amount of the recycled styrene block copolymer (B) in the polyolefin composition (I);

[0094] - The tensile modulus is measured on injection-molded specimens obtained according to method ISO 1873-2:2007 in accordance with method ISO 527-3; and

[0095] - The relative amounts of components (A) and (B) refer to the sum of components (A)+(B).

[0096] The polyolefin composition (I) has thermal properties comparable to those of the polypropylene composition (A), such as Vicat softening temperature and heat distortion temperature (HDT).

[0097] Determined by the Charpy impact test, the impact properties of the polyolefin composition (I) at 23 °C are substantially the same as those of the polypropylene composition (A).

[0098] The polyolefin composition (I) is particularly suitable for the production of injection-molded or extruded articles. Accordingly, the present disclosure relates to an article comprising or consisting of the polyolefin composition (I).

[0099] Preferably, the article is an extruded article, such as a film or a sheet.

[0100] Due to the soft touch and low tack, the film or sheet is particularly suitable for use as artificial leather, especially in the automotive field.

[0101] The features characterizing the subject matter of the present disclosure are not inseparably linked to each other. Thus, the preferred ranges of one feature can be combined with more or less preferred ranges of different features, regardless of their preferred levels.

[0102] Examples

[0103] The following examples are merely illustrative and are not intended to limit the scope of the present disclosure in any way.

[0104] Characterization methods: The following methods are used to determine the properties indicated in the description, claims, and examples.

[0105] Melt flow rate: Measured according to method 1133-1:2011 (using conditions of 230 °C / 2.16 kg).

[0106] Solubility in xylene at 25 °C: 2.5 g of a polymer sample and 250 ml of xylene are added to a glass flask equipped with a cooler and a magnetic stirrer. The temperature is raised to 135 °C within 30 minutes. The resulting clear solution is kept under reflux and stirred for another 30 minutes. The solution is cooled in two stages. In the first stage, the temperature is lowered to 100 °C in air with stirring for 10 to 15 minutes. 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 kept at 25 °C with stirring during the last 10 minutes. The formed solid is filtered on a rapid filter paper (e.g., Whatman filter paper grade 4 or 541). 100 ml of the filtered solution (S1) is poured into a pre-weighed aluminum container, which is heated on a hot plate under a nitrogen stream to 140 °C to remove the solvent by evaporation. Then the container is kept in an oven at 80 °C under vacuum until a constant weight is reached. Then the amount of polymer soluble in xylene at 25 °C is calculated. The XS(I) and XS A values are determined experimentally. The fraction (XS B ) of component (B) soluble in xylene at 25 °C can be calculated by the following formula:

[0107] XS = W(A) × (XS A ) + W(B) × (XS B )

[0108] where W(A) and W(B) are the relative amounts of component (A) and (B), respectively, and W(A) + W(B) = 1.

[0109] Intrinsic viscosity of the xylene-soluble fraction: To calculate the value of the intrinsic viscosity IV, the flow time of the polymer solution is compared with the flow time of the solvent (THN). A Ubbelohde-type glass capillary viscometer is used. The oven temperature is adjusted to 135 °C. Before starting the measurement of the solvent flow time t0, the temperature must be stable (135 °C ± 0.2 °C). The sample meniscus of the viscometer is detected by an optoelectronic device.

[0110] Sample preparation: Pour 100 ml of the filtered solution (S1) into a beaker and add 200 ml of acetone with vigorous stirring. The precipitation of the insoluble fraction must be complete, as confirmed by the clear solid-solution separation. Filter the suspension through a weighed metal sieve (200 mesh), rinse the beaker and wash the precipitate with acetone to completely remove o-xylene. Dry the precipitate in a vacuum oven at 70 °C until a constant weight is reached. Weigh 0.05 g of the precipitate and dissolve it in 50 ml of tetralin (THN) at a temperature of 135 °C. Measure the efflux time t of the sample solution and convert it to the intrinsic viscosity value [η] using the Huggins equation (Huggins, M. L., Journal of the American Chemical Society (J. Am. Chem. Soc.) 1942, 64, 11, 2716 to 2718) and the following data:

[0111] - Concentration of the sample (g / dl);

[0112] - Density of the solvent at a temperature of 135 °C;

[0113] - Flow time t0 of the solvent on the same viscometer at a temperature of 135 °C.

[0114] Use a single polymer solution to determine [η].

[0115] Comonomer content of the polypropylene-ethylene polymer: Determined by IR using a Fourier transform infrared spectrometer (FTIR). The spectra of the polymer pressed films are recorded as absorbance versus wavenumber (cm-1). The following measurements are used to calculate the ethylene content:

[0116] - Area (At) of the combined absorption band between 4482 and 3950 cm -1 which is used for spectral normalization of the film thickness;

[0117] - Subtract the linear baseline and eliminate the remaining constant offset in the range of 790 - 660 cm -1 ;

[0118] - The ethylene content is obtained by applying partial least squares (PLS1) multivariate regression to the range of 762 - 688 cm -1 .

[0119] The method was calibrated using polymer standards based on 13C NMR analysis.

[0120] Sample preparation: Using a hydraulic press, a thick sheet was obtained by pressing approximately 1 g of the sample between two aluminum foils. The pressing temperature was 180 ± 10 °C (356 °F), and the pressure was approximately 10 kg / cm 2 , for approximately 1 minute (at least two pressing operations for each specimen). A small portion was cut from the sheet to mold a film. The recommended film thickness range was 0.02 to 0.05 cm.

[0121] Injection molded specimens: Specimens of 80 × 10 × 4 mm were obtained according to Method ISO 1873-2:2007.

[0122] Flexural modulus: Measured on injection molded specimens according to Method ISO 178:2010.

[0123] Tensile modulus: Measured on injection molded specimens according to Method ISO 527-3.

[0124] Charpy impact test: The Charpy impact values at different temperatures were measured on injection molded specimens according to ISO 179-1:2010eA.

[0125] Gloss: Measured on 60 x 60 x 2 mm injection molded test specimens obtained according to Method ISO 294-3:2020 according to Method ASTM D2457-13 (60° angle).

[0126] Vicat softening temperature: Measured according to Method ISO306 (9.81.N). Samples (4 mm thick, 10 mm wide) were cut from the tensile injection molded block. At least 3 samples should be tested for each test, and usually six silicone oil baths were used as the test environment. Initial temperature: 25 °C; Scanning rate: 50 °C / h; Load: 1 Kg (9.81 N).

[0127] Heat distortion temperature (HDT): Measured according to Method ISO75B (0.45 Mpa).

[0128] Raw materials:

[0129] HECO1 and HECO2 : Prepared according to the procedure reported in Example 1 of WO2007 / 042375. Different polymerization conditions were reported in Table 1a. Using a Ziegler-Natta catalyst system, the Ziegler-Natta catalyst system included:

[0130] - A solid titanium catalyst component prepared using diisobutyl phthalate as an internal donor according to the method described in Example 3 of EP395083;

[0131] - Triethylaluminum (TEAL) as a cocatalyst; and

[0132] - Dicyclopentyldimethoxysilane (DCPMS) as an external donor.

[0133] Table 1a

[0134]

[0135]

[0136] Table 1b describes the composition reports of HECO 1 and HECO2.

[0137] Table 1b

[0138]

[0139]

[0140] Add 0.1 wt% of 168 (tris(2,4 - di - tert - butylphenyl) phosphite) to the polymer obtained from the polymerization reaction.

[0141] rSBC1 : Recycled styrene - butadiene - styrene block copolymer obtained by mechanical recycling of pre - consumer waste, with an MFR(B) of 7.4 g / 10 min and a solubility in xylene at 25 °C of 39.3 wt%.

[0142] rSBC2 : Recycled styrene - butadiene - styrene block copolymer obtained by mechanical recycling of pre - consumer waste, with an MFR(B) of 4.1 g / 10 min and a solubility in xylene at 25 °C of 88.0 wt%. This r - SBC1 contains 3 wt% talc, 3 wt% polypropylene, and 4 wt% polyethylene.

[0143] Examples E1 to E2

[0144] The polypropylene composition HECO1 (corresponding to CE1) prepared as described above was melt - blended with sSBC1 (corresponding to CE2) in the proportions shown in Table 2. The polymer pellets were extruded by a Berstorff type 3 twin - screw extruder under a nitrogen atmosphere at a rotational speed of 250 rpm and a melting temperature of 200 ° - 250 °C.

[0145] The measured properties are reported in the same Table 2.

[0146] Table 2

[0147]

[0148] Examples E3 to E4

[0149] The polypropylene composition HECO2 (corresponding to CE3) prepared as described above was melt blended with sSBC1 (corresponding to CE2) in the proportions shown in Table 3. The polymer pellets were extruded by a Berstorff Type 3 twin-screw extruder under a nitrogen atmosphere at a rotational speed of 250 rpm and a melting temperature of 200° - 250 °C.

[0150] The measured properties are reported in Table 3.

[0151] Table 3

[0152]

[0153] Examples E5 to E6

[0154] The polypropylene composition HECO2 (corresponding to CE3) prepared as described above was melt blended with sSBC2 (corresponding to CE4) in the proportions shown in Table 4. The polymer pellets were extruded by a Berstorff Type 3 twin-screw extruder under a nitrogen atmosphere at a rotational speed of 250 rpm and a melting temperature of 200° - 250 °C.

[0155] The measured properties are reported in Table 4.

[0156] Table 4

[0157]

Claims

1. A polyolefin composition (I), the polyolefin composition comprising: (A) 70% to 97% by weight of a polypropylene composition, the polypropylene composition comprising: - 20 wt% to 45 wt% of a polymer fraction (a), said polymer fraction (a) comprising a propylene polymer selected from propylene homopolymers, propylene copolymers and combinations thereof, said propylene copolymer containing up to and including 15.0 wt% of units derived from a comonomer, based on the weight of said propylene copolymer, said comonomer being selected from ethylene, CH 2 =CHR type α-olefins, where R is a linear or branched C2-C8 alkyl group, The polymer fraction (a) has a solubility in xylene (XS(a)) at 25 °C equal to or lower than 10.0% by weight, based on the weight of the fraction (a); and - 55% to 80% by weight of a polymer fraction (b), said polymer fraction (b) comprising a copolymer of ethylene and a comonomer selected from propylene, CH 2 =CHR type α-olefins, where R is a linear or branched C2-C8 alkyl group, and combinations thereof, wherein said ethylene copolymer contains more than 50.0% by weight of units derived from ethylene, based on the weight of said ethylene copolymer, The polymer fraction (b) has a solubility in xylene (XS(b)) at 25 °C equal to or higher than 60.0% by weight, based on the weight of the fraction (b), wherein the amounts of fraction (a) and fraction (b) are based on the total weight of (a)+(b), and (B) 3% to 30% by weight of a recycled styrene block copolymer, the recycled styrene block copolymer having a melt flow rate MFR(B) of from 2.0 to 15.0 g / 10 min (measured according to ISO 1133-1:2011, using the 230 °C / 2.16 kg condition), wherein the amounts of (A) and (B) are based on the total amount of (A)+(B).

2. The polyolefin composition (I) according to claim 1, the polyolefin composition comprising: - 75% to less than 95% by weight, preferably 78% to 93% by weight, more preferably 78% to 88% by weight of the polypropylene composition (A), and - more than 5% to 25% by weight, preferably 7% to 22% by weight, more preferably 12% to 22% by weight of the recycled styrene block copolymer (B), wherein the amounts of (A) and (B) are based on the total amount of (A)+(B).

3. The polyolefin composition (I) according to claim 1 or 2, wherein the polypropylene composition (A) comprises: -20 wt% to 45 wt%, preferably 25 wt% to 40 wt% of polymer fraction (a), said polymer fraction (a) comprising a propylene polymer selected from propylene homopolymers, propylene copolymers and combinations thereof, wherein said propylene copolymer contains up to and including 15.0 wt%, preferably 0.1 wt% to 15.0 wt%, more preferably 0.5 wt% to 5.0 wt% of units derived from comonomers based on the weight of said propylene copolymer, said comonomers being selected from ethylene, CH 2 =CHR type α-olefins, where R is a linear or branched C2-C8 alkyl group, The polymer fraction (a) has a solubility in xylene (XS(a)) at 25 °C equal to or lower than 10.0% by weight, preferably equal to or lower than 6.0% by weight, more preferably from 0.5% to 6.0% by weight, based on the weight of the fraction (a); and - 55% to 80% by weight, preferably 60% to 75% by weight, of polymer fraction (b), said polymer fraction (b) comprising a copolymer of ethylene and a comonomer selected from propylene, CH 2 =CHR type α-olefins, where R is a linear or branched C2-C8 alkyl group, wherein said ethylene copolymer contains greater than 50.0% by weight, preferably 51.0% to 70.0% by weight, more preferably 52.0% to 65.0% by weight, based on the weight of said ethylene copolymer, of units derived from ethylene, The polymer fraction (b) has a solubility in xylene (XS(b)) at 25 °C equal to or higher than 60.0% by weight, preferably from 60.0% to 90.0% by weight, more preferably from 65.0% to 85.0% by weight, still more preferably from 70.0% to 80.0% by weight, based on the weight of the fraction (b), wherein the amounts of fraction (a) and fraction (b) are based on the total weight of (a)+(b).

4. The polyolefin composition (I) according to any one of claims 1 to 3, wherein the fraction (a) comprised in the polypropylene composition (A) has at least one of the following properties, preferably all of the properties: - comprises a propylene polymer selected from a propylene homopolymer, a propylene copolymer and combinations thereof, the copolymer containing at most and including 15.0% by weight, preferably 0.1% to 15.0% by weight, more preferably 0.5% to 5.0% by weight of units derived from a comonomer, the comonomer being selected from ethylene, butene-1, hexene-1 and combinations thereof, most preferably ethylene; and / or - The melt flow rate MFR(a) (measured according to ISO 1133-1:2011 under the conditions of 260 °C / 2.16 kg) ranges from 2.0 to 70 g / 10 min, preferably from 5.0 to 40 g / 10 min.

5. The polyolefin composition (I) according to any one of claims 1 to 4, wherein the fraction (b) comprises a copolymer of ethylene and a comonomer selected from the group consisting of propylene, butene-1, hexene-1, and combinations thereof, most preferably propylene, and the copolymer contains more than 50.0% by weight, preferably from 51.0% to 70.0% by weight, more preferably from 52.0% to 65.0% by weight of units derived from the comonomer, preferably derived from propylene.

6. The polyolefin composition (I) according to any one of claims 1 to 5, wherein the polypropylene composition (A) has at least one of the following properties, preferably all of the properties: - The melt flow rate MFR(A) ranges from 0.05 to 5.0 g / 10 min, preferably from 0.1 to 3.0 g / 10 min, more preferably from 0.2 to 1.0 g / 10 min; and / or - The intrinsic viscosity X(A) of the fraction soluble in xylene at 25 °C is equal to or greater than 2.0 dl / g, preferably from 2.5 to 6.0 dl / g, more preferably from 3.0 to 5.0 dl / g; and / or - The flexural modulus is equal to or lower than 600 MPa, preferably from 50 to 600 MPa, more preferably from 80 to 400 MPa, still more preferably from 100 to 350 MPa, determined according to method ISO 178:2010.

7. The polyolefin composition (I) according to any one of claims 1 to 6, wherein the recycled styrene block copolymer (B) comprises a copolymer selected from the group consisting of polystyrene-polybutadiene-polystyrene (SBS), polystyrene-poly(ethylene-butene)-polystyrene (SEBS), polystyrene-poly(ethylene-propylene)-polystyrene (SEPS), polystyrene-polyisoprene-polystyrene (SIS), polystyrene-poly(isoprene-butadiene)-polystyrene (SIBS), and mixtures thereof, preferably a polystyrene-polybutadiene-polystyrene (SBS) block copolymer.

8. The polyolefin composition (I) according to any one of claims 1 to 7, wherein the recycled styrene block copolymer (B) is a recycled polystyrene-polybutadiene-polystyrene (rSBS) block copolymer derived from pre-consumer waste.

9. The polyolefin composition (I) according to any one of claims 1 to 8, wherein the recycled styrene block copolymer (B) contains at most and including 20.0% by weight, preferably from 0.5% to 20.0% by weight, more preferably from 1.0% to 15.0% by weight, still more preferably from 3.0% to 12.0% by weight of materials based on the weight of component (B), and the materials are selected from polypropylene, polyethylene, inorganic fillers (preferably talc), and mixtures thereof.

10. The polyolefin composition (I) according to any one of claims 1 to 9, wherein the recycled styrene block copolymer (B) has at least one, preferably all, of the following properties: - The melt flow rate MFR(B) (measured according to ISO 1133-1:2011 under the conditions of 230 °C / 2.16 kg) ranges from 2.0 to 12.0 g / 10 min, preferably from 3.0 to 10.0 g / 10 min; and / or - The tensile modulus ranges from 30 to 400 MPa, preferably from 100 to 350 MPa, measured according to method ISO 527-3; and / or - The Charpy impact value at 23 °C is equal to or greater than 50 kJ / m 2 , preferably equal to or greater than 60 kJ / m 2 , determined according to method ISO179-1eA; and / or -Charpy impact value at -20 °C is equal to or greater than 80 kJ / m 2 , preferably equal to or greater than 90 kJ / m 2 , determined according to method ISO179-1eA; and / or - The Vicat softening temperature is in the range of 35 °C to 95 °C, preferably 40 °C to 95 °C, more preferably 70 °C to 95 °C, still more preferably 75 °C - 90 °C, measured according to method ISO 306 (9.81 N); and / or - The heat distortion temperature (HDT) is equal to or lower than 55 °C, more preferably equal to or lower than 50 °C, measured according to method ISO 075B (0.45 Mpa, flat, 48 h).

11. The polyolefin composition (I) according to any one of claims 1 to 10, wherein the melt flow rate MFR(I) of the polyolefin composition (measured according to ISO 1133-1:2011 under the conditions of 230 °C / 2.16 kg) ranges from 0.1 to 5.0 g / 10 min, preferably from 0.2 to 2.0 g / 10 min, more preferably from 0.3 to 1.0 g / 10 min.

12. The polyolefin composition (I) according to any one of claims 1 to 11, wherein the polyolefin composition has a tensile modulus Tmod(I), and the tensile modulus Tmod(I) satisfies the following equation: Tmod(I)≥Tmod(A)W(A)+Tmod(B)W(B) where - Tmod(I) is the tensile modulus of the polyolefin composition (I), Tmod(A) is the tensile modulus of the polypropylene composition (A), W(A) is the relative amount of the polypropylene composition (A) in the polyolefin composition (I), Tmod(B) is the tensile modulus of the recycled styrene block copolymer (B), and W(B) is the relative amount of the recycled styrene block copolymer (B) in the polyolefin composition (I); - The tensile modulus is measured according to method ISO 527-3; and - The relative amounts of (A) and (B) are relative to the sum of components (A) + (B).

13. An article, the article comprising the polyolefin composition (I) according to any one of claims 1 to 12.

14. The article according to claim 13, wherein the article is an extruded article, preferably a film or a sheet.

15. The article according to claim 13 or 14, wherein the article is used as artificial leather for automotive interiors.

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