Polymer composition with high gloss, low shrinkage and high impact resistance

Abstract

The present invention relates to a polymer composition comprising a first heterophasic propylene copolymer, a second heterophasic propylene copolymer, and an ethylene-based elastomer. The present invention further relates to a process for preparing the polymer composition. The present invention further relates to an automotive part comprising the polymer composition. The polymer composition according to the present invention has high gloss, low shrinkage, and high impact resistance.

Description

[0001] The present invention relates to a polymer composition comprising a first heterophasic propylene copolymer, a second heterophasic propylene copolymer and an ethylene-based elastomer. The present invention further relates to a process for preparing the polymer composition. The present invention further relates to an automotive part comprising such a polymer composition.

[0002] Due to the properties of polypropylene, it is desirable in the automotive industry to use low-shrinkage propylene-based polymer compositions to manufacture bumpers. Such bumpers are known in the art. For example, WO 2011144705A1 discloses a multi-component polypropylene polymer, and injection-molded articles manufactured from the multi-component polypropylene polymer exhibit excellent scratch resistance and, in particular, low shrinkage anisotropy; US 9023935B2 discloses a composition comprising a polypropylene-based resin and a polyethylene-based resin, wherein the composition has an excellent balance of properties, in particular, high hardness and good impact strength.

[0003] Recent developments in the automotive industry have also led to a trend towards bumpers with a higher gloss finish.

[0004] There remains a need for automotive bumpers made from polymer compositions having low shrinkage, high gloss, while maintaining high impact resistance.

[0005] In the context of the present invention, "low shrinkage" means that the average shrinkage value of the polymer composition is less than 0.93%, wherein the average shrinkage value is measured according to ISO 294-4:2018 24 hours after injection, the conditioning temperature is 23 ° C. "High gloss" means that the gloss value of the polymer composition at 20 ° is at least 55, wherein the gloss is measured according to ISO 2813:2014. "High impact resistance" means that the impact resistance of the polymer composition at 23 ° C according to ISO 180:2000 is at least 50 kJ / m 2 .

[0006] This need is met by a polymer composition comprising a first heterophasic propylene copolymer (a), a second heterophasic propylene copolymer (b) and an ethylene-based elastomer, wherein the amount of the first heterophasic propylene copolymer (a) is 23.1 to 73.7 wt%, based on the total amount of the polymer composition, wherein the amount of the second heterophasic propylene copolymer (b) is 21.2 to 64.5 wt%, based on the total amount of the polymer composition, and wherein the amount of the ethylene-based elastomer is 16.9 to 27.6 wt%, based on the total amount of the polymer composition,

[0007] wherein the first heterophasic propylene copolymer (a) comprises:

[0008] 65-81 wt% of propylene polymer (a1),

[0009] 19-35 wt% of an ethylene-α-olefin copolymer (a2), wherein the α-olefin moiety in the ethylene-α-olefin copolymer (a2) is derived from at least one α-olefin having 3 to 20 carbon atoms,

[0010] wherein the first heterophasic propylene copolymer (a) has an MFI of 10 to 100 dg / min, determined according to ISO 1133-1:2011 at 230 °C and 2.16 kg load,

[0011] wherein the xylene soluble fraction of the second heterophasic propylene copolymer (b) is 12 to 27 wt%, based on the total amount of the second heterophasic propylene copolymer (b), as determined by ISO 16152:2005, wherein the intrinsic viscosity of the xylene soluble fraction of the second heterophasic propylene copolymer (b) is 2.9 to 4.6 dl / g, as measured according to ISO 1628-1:2009 in decalin at 135 °C; wherein the MFI of the second heterophasic propylene copolymer (b) is 5.6 to 65 dg / min, as measured according to ISO 1133-1:2011 at 230 °C and 2.16 kg load,

[0012] The density of the ethylene-based elastomer is 0.868-0.943 g / cm 3 , which is determined according to ASTM D792-13.

[0013] The inventors of the present invention surprisingly found that a car bumper made from the polypropylene composition has low shrinkage and high gloss while maintaining high impact resistance.

[0014] First heterophasic propylene copolymer (a)

[0015] The first heterophasic propylene copolymer (a) comprises a first propylene polymer (a1 ) as matrix and a first ethylene-α-olefin copolymer (a2) as dispersed phase.

[0016] The amount of the first propylene polymer (a1 ) is 65 to 81 wt%, preferably 70 to 75 wt%, based on the total amount of the first heterophasic propylene copolymer (a).

[0017] The first propylene polymer (a1) in the first heterophasic propylene copolymer (a) can be a propylene homopolymer or / and a propylene-α-olefin copolymer, wherein the α-olefin has 2 or 4 to 20 carbon atoms, for example the propylene-α-olefin can be a propylene-ethylene copolymer or a propylene-butene copolymer. Preferably, the first propylene polymer (a1) in the first heterophasic propylene copolymer (a) is a propylene homopolymer.

[0018] The MFI of the first propylene polymer (a1 ) in the first heterophasic propylene copolymer (a) is preferably 20-150 dg / min, preferably 50-100 dg / min, more preferably 60-85 dg / min, measured according to ISO 1133-1:201 1 at 230°C and 2.16 kg load.

[0019] The amount of the first ethylene-α-olefin copolymer (a2) is 19 to 35 wt%, preferably 25 to 30 wt%, based on the total amount of the first heterophasic propylene copolymer (a).

[0020] In the first heterophasic propylene copolymer (a) the amount of moieties derived from ethylene is preferably 55 to 68 wt-%, based on the total amount of the first ethylene-α-olefin copolymer (a2).

[0021] The α-olefin moiety in the first ethylene-α-olefin copolymer (a2) of the first heterophasic propylene copolymer (a) is derived from at least one α-olefin having 3 to 20 carbon atoms, for example, the first ethylene-α-olefin copolymer (a2) may be an ethylene-propylene copolymer, for example, the first ethylene-α-olefin copolymer (a2) may be an ethylene-butene copolymer, for example, the first ethylene-α-olefin copolymer (a2) may be an ethylene-hexene copolymer, for example, the first ethylene-α-olefin copolymer (a2) may be an ethylene-octene copolymer, for example, the first ethylene-α-olefin copolymer (a2) may be an ethylene-propylene-butene copolymer, for example, the first ethylene-α-olefin copolymer (a2) may be an ethylene-propylene-hexene copolymer. Preferably, the first ethylene-α-olefin copolymer (a2) in the first heterophasic propylene copolymer (a) is an ethylene-propylene copolymer.

[0022] Preferably, the first heterophasic propylene copolymer (a) has an MFI of 10-100 dg / min, preferably 15-80 dg / min, more preferably 23-65 dg / min, most preferably 30-50 dg / min, determined according to ISO 1133-1:2011 at 230°C and 2.16 kg load.

[0023] The first heterophasic propylene copolymer (a) can be divided into a first xylene soluble fraction (first CXS) and a first xylene insoluble fraction (first CXI). The amount of the xylene soluble fraction (first CXS) of the first heterophasic propylene copolymer (a) is 10 to 27 wt%, preferably 15 to 23 wt%, based on the total amount of the first heterophasic propylene copolymer (a), as determined according to ISO 16152:2005. The amount of the first xylene insoluble fraction, based on the total amount of the first heterophasic propylene copolymer, is calculated by the following equation:

[0024] First CXI=100 wt%-first CXS

[0025] Intrinsic viscosity IV of the first xylene insoluble fraction (first CXI) of the first heterophasic propylene copolymer (a) 第一CXI It is 1.0-2.0 dl / g, more preferably 0.8-1.6 dl / g, more preferably 1.1-1.5 dl / g, even more preferably 1.2-1.4 dl / g, as measured according to ISO 1628-3:2010.

[0026] Intrinsic viscosity IV of the first xylene soluble fraction (first CXS) of the first heterophasic propylene copolymer (a) 第一CXS It is 1.7-3.1 dl / g, more preferably 1.9-2.8 dl / g, even more preferably 2.0-2.5 dl / g, as measured according to ISO 1628-1:2009.

[0027] The first heterophasic propylene copolymer (a) is preferably a non-visbroken heterophasic propylene copolymer. The term non-visbroken is known in the art, but for the avoidance of doubt, it means that the material has not been treated immediately after polymerization, for example to change the molecular weight and / or molecular weight distribution of the polymer. In other words, the non-visbroken polymer has not been treated with peroxides, radiation or any other initiating source for chain scission reactions to occur. One advantage of non-visbroken polypropylene over visbroken polypropylene is that the former generally releases less low molecular weight materials, which are inherently produced by visbreaking and are undesirable for automotive applications. For the avoidance of doubt, the term reactor grade means that the copolymer is non-visbroken. The first heterophasic propylene copolymer (a) is preferably a reactor grade heterophasic propylene copolymer.

[0028] Processes for producing the first heterophasic propylene copolymer (a) are known in the art. Preferably, the first heterophasic propylene copolymer (a) is produced in a continuous polymerization process comprising at least two reactors, more preferably the instant polypropylene is produced in a continuous polymerization process comprising at least three reactors.

[0029] The catalysts used to prepare the first heterophasic propylene copolymer (a) are also known in the art, such as Ziegler-Natta catalysts, metallocene catalysts. Preferably, the catalyst used to produce the first heterophasic propylene copolymer does not contain phthalates, for example the catalyst comprises a compound of an IUPAC Group 4-6 transition metal, a Group 2 metal compound and an internal donor, wherein the internal donor is a compound selected from the group consisting of optionally substituted malonates, maleates, succinates, glutarates, cyclohexene-1,2-dicarboxylates, benzoates, citraconates, and derivatives thereof and / or mixtures thereof.

[0030] For example, the catalyst used for the preparation of the first heterophasic propylene copolymer (a) is a Ziegler-Natta catalyst comprising a procatalyst, at least one external donor, a cocatalyst and optionally an internal donor, wherein the external donor is selected from the group consisting of a catalyst having a molecular weight according to formula III: (R 90 )2N-Si(OR 91 )3, having a structure according to formula IV: (R 92 )Si(OR 93 )3 structure of the compound, and mixtures thereof, wherein each R 90 , R 91 , R 92 and R 93 The groups are each independently a linear, branched or cyclic, substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, preferably a linear unsubstituted alkyl group having 1 to 8 carbon atoms, preferably an ethyl group, a methyl group or an n-propyl group.

[0031] In one embodiment, R 90 and R 91 Each is ethyl (the compound of formula III is diethylaminotriethoxysilane, DEATES). In another embodiment, R 92 is n-propyl and R 93 Each is ethyl (the compound of Formula IV is n-propyltriethoxysilane, nPTES), or in another embodiment R 92 is n-propyl and R 93 Each is methyl (the compound of formula IV is n-propyltrimethoxysilane, nPTMS).

[0032] Preferably, the heterophasic propylene copolymer of the present invention is prepared by a catalyst system comprising a Ziegler-Natta catalyst and at least one external electron donor selected from the group consisting of: a copolymer having a molecular weight according to formula III: (R 90 )2N-Si(OR 91 )3, having a structure according to formula IV: (R 92 )Si(OR 93 )3 structure compounds, and mixtures thereof.

[0033] "Promoter" is a term well known in the field of Ziegler-Natta catalysts and is recognized as a substance capable of converting a primary catalyst into an active polymerization catalyst. Typically, a promotor is an organometallic compound containing a metal selected from Groups 1, 2, 12, or 13 of the Periodic Table of the Elements (Handbook of Chemistry and Physics, 70th edition, CRC Press, 1989-1990). Promotor can include any compound known in the art as a "promoter", such as hydrides, alkylates, or arylates of aluminum, lithium, zinc, tin, cadmium, beryllium, magnesium, and combinations thereof. The cocatalyst may be a hydrocarbyl aluminum cocatalyst, such as triisobutylaluminum, trihexylaluminum, diisobutylaluminum hydride, dihexylaluminum hydride, isobutylaluminum dihydride, hexylaluminum dihydride, diisobutylhexylaluminum, isobutyldihexylaluminum, trimethylaluminum, triethylaluminum, tripropylaluminum, triisopropylaluminum, tri-n-butylaluminum, trioctylaluminum, tridecylaluminum, tridodecylaluminum, tribenzylaluminum, triphenylaluminum, trinaphthylaluminum, and tritolylaluminum. In one embodiment, the cocatalyst is selected from triethylaluminum, triisobutylaluminum, trihexylaluminum, diisobutylaluminum hydride, and dihexylaluminum hydride, more preferably trimethylaluminum, triethylaluminum, triisobutylaluminum, and / or trioctylaluminum, and most preferably triethylaluminum (abbreviated as TEAL). The cocatalyst may also be a hydrocarbyl aluminum compound such as tetraethyldialuminoxane, methylaluminoxane, isobutylaluminoxane, tetraisobutyldialuminoxane, diethylaluminum ethoxide, diisobutylaluminum chloride, methylaluminum dichloride, diethylaluminum chloride, ethylaluminum dichloride and dimethylaluminum chloride, preferably TEAL.

[0034] For example, the procatalyst can be prepared by a method comprising the steps of providing a magnesium-based support, contacting the magnesium-based support with a Ziegler-Natta type catalytic material, an internal donor, and an activator to produce the procatalyst. For example, the examples of Dow's US Pat. No. 5,093,415 disclose an improved method for preparing the procatalyst. Preferably, the procatalyst is a titanium-containing chemical compound.

[0035] In the context of the present invention, the molar ratio of Si to Ti elements of the catalyst system is preferably 0.1 to 40, preferably 0.1 to 20, even more preferably 1 to 20, most preferably 2 to 10. Preferably, the molar ratio of Al to Ti elements of the catalyst system is 5 to 500, preferably 15 to 200, more preferably 30 to 160, most preferably 50 to 140.

[0036] In one embodiment, the molar ratio between Si and Ti elements is the molar ratio between the external donor and the procatalyst.

[0037] In one embodiment, the molar ratio between Al and Ti elements is the molar ratio between the co-catalyst and the main catalyst.

[0038] Second heterophasic propylene copolymer (b)

[0039] The second heterophasic propylene copolymer (b) preferably comprises the second propylene polymer (b1 ) as matrix and the second ethylene-α-olefin copolymer (b2) as dispersed phase.

[0040] The amount of the second propylene polymer (b1 ) is preferably 65 to 81 wt%, preferably 70 to 76 wt%, based on the total amount of the second heterophasic propylene copolymer (b).

[0041] The second propylene polymer (b1) in the second heterophasic propylene copolymer (b) may be a propylene homopolymer or / and a propylene-α-olefin copolymer, wherein the α-olefin has 2 or 4 to 20 carbon atoms, for example the propylene-α-olefin may be a propylene-ethylene copolymer or a propylene-butene copolymer. Preferably, the second propylene polymer (b1) in the second heterophasic propylene copolymer (b) is a propylene homopolymer.

[0042] The second propylene polymer (b1 ) in the second heterophasic propylene copolymer (b) preferably has an MFI of 20 to 150 dg / min, preferably 50 to 100 dg / min, more preferably 60 to 90 dg / min, measured according to ISO 1133-1 :201 1 at 230 °C and 2.16 kg load.

[0043] The amount of the second ethylene-α-olefin copolymer (b2) is preferably 19 to 35 wt%, preferably 24 to 30 wt%, based on the total amount of the second heterophasic propylene copolymer (b).

[0044] In the second heterophasic propylene copolymer (b) the amount of moieties derived from ethylene is preferably 55 to 68 wt-%, based on the total amount of the second ethylene-α-olefin copolymer (b2).

[0045] The α-olefin moiety in the second ethylene-α-olefin copolymer (b2) of the second heterophasic propylene copolymer (b) is preferably derived from at least one α-olefin having 3 to 20 carbon atoms, for example the second ethylene-α-olefin copolymer (b2) may be an ethylene-propylene copolymer, for example the second ethylene-α-olefin copolymer (b2) may be an ethylene-butene copolymer, for example the second ethylene-α-olefin copolymer (b2) may be an ethylene-hexene copolymer, for example the second ethylene-α-olefin copolymer (b2) may be an ethylene-octene copolymer, for example the second ethylene-α-olefin copolymer (b2) may be an ethylene-propylene-butene copolymer, for example the second ethylene-α-olefin copolymer (b2) may be an ethylene-propylene-hexene copolymer. Preferably, the second ethylene-α-olefin copolymer (b2) in the second heterophasic propylene copolymer (b) is an ethylene-propylene copolymer.

[0046] The second heterophasic propylene copolymer (b) has an MFI of 5.6 to 65 dg / min, more preferably 7.1 to 53 dg / min, more preferably 10.3 to 39 dg / min, more preferably 12.5 to 27 dg / min, measured according to ISO 1133-1:2011 at 230°C and 2.16 kg load.

[0047] The second heterophasic propylene copolymer (b) can be separated into a second xylene soluble fraction (second CXS) and a second xylene insoluble fraction (second CXI). The amount of the second xylene soluble fraction of the second heterophasic propylene copolymer (b) is 12 to 27 wt%, preferably 16 to 25 wt%, more preferably 18 to 23 wt%, based on the total amount of the second heterophasic propylene copolymer (a), as determined according to ISO 16152:2005.

[0048] Intrinsic viscosity IV of the second xylene soluble fraction (second CXS) of the second heterophasic propylene copolymer (b) 第二CXS It is 2.9-4.6 dl / g, more preferably 3.5-4.4 dl / g, even more preferably 3.8-4.2 dl / g, as measured according to ISO 1628-1:2009.

[0049] The second heterophasic propylene copolymer (b) is preferably a reactor grade heterophasic propylene copolymer.

[0050] The second heterophasic propylene copolymer (b) can be produced using methods and catalysts known in the art.

[0051] In one embodiment the second heterophasic propylene copolymer (b) is produced in the same process as the first heterophasic propylene copolymer (a).

[0052] In one embodiment the second heterophasic propylene copolymer (b) is produced with the same catalyst as the first heterophasic propylene copolymer (a).

[0053] Ethylene-based elastomers

[0054] The polymer composition according to the present invention comprises an ethylene-based elastomer. The ethylene-based elastomer is preferably an ethylene-α-olefin copolymer, wherein the α-olefin has 3 to 20 carbon atoms, for example, the ethylene-α-olefin copolymer is an ethylene-propylene copolymer, for example, the ethylene-α-olefin copolymer is an ethylene-butene copolymer, for example, the ethylene-α-olefin copolymer is an ethylene-hexene copolymer, for example, the ethylene-α-olefin copolymer is an ethylene-octene copolymer, or a combination thereof.

[0055] Preferably, the ethylene-based elastomer is an ethylene-butene copolymer or / and an ethylene-octene copolymer. More preferably, the ethylene-based elastomer is an ethylene-octene copolymer.

[0056] Preferably, the amount of the ethylene-derived moiety in the ethylene-based elastomer is 45-90 wt%, preferably 50-87 wt%, more preferably 55-85 wt%, more preferably 57-70 wt%, based on the total amount of the ethylene-based elastomer.

[0057] The ethylene-based elastomer according to the present invention preferably has a Shore A hardness of 40-85, more preferably 51-79, more preferably 54-68, as measured according to ASTM D2240-15.

[0058] The density of the ethylene-based elastomer according to the present invention is 0.868-0.943 g / cm 3 , preferably 0.869-0.896 g / cm 3 , more preferably 0.869-0.882 g / cm 3 , more preferably 0.869-0.876 g / cm 3 , which is measured according to ASTM D792-13.

[0059] The MFI of the ethylene-based elastomer is preferably 0.20-20.0 dg / min, preferably 1.3-14.3 dg / min, more preferably 2.6-7.2 dg / min, as measured at 190° C. using a 2.16 kg load according to ASTM D1238-13.

[0060] The ethylene-based elastomer can be prepared using methods known in the art, such as using a single-site catalyst, i.e., a catalyst whose transition metal component is an organometallic compound and whose at least one ligand has a cyclopentadienyl anionic structure that is coordinated to the transition metal cation through its bonding. Such catalysts are also known as "metallocene" catalysts. Metallocene catalysts are described, for example, in U.S. Patent Nos. 5,017,714 and 5,324,820. The ethylene-based elastomer can also be prepared using conventional heterogeneous multi-site Ziegler-Natta catalysts.

[0061] Optional inorganic filler

[0062] The polymer composition according to the present invention may further comprise an inorganic filler.

[0063] Suitable examples of inorganic fillers include, but are not limited to, talc, calcium carbonate, wollastonite, barium sulfate, kaolin, glass flakes, layered silicates (bentonite, montmorillonite, smectite), and mica.

[0064] For example, the inorganic filler is selected from talc, calcium carbonate, wollastonite, mica and mixtures thereof.

[0065] More preferably, the inorganic filler is talc.The talc median particle size (D50) of the talc is preferably 0.1-10.2 μm, preferably 0.3-8.1 μm, more preferably 0.5-5.2 μm, even more preferably 0.6-2.5 μm, as determined by sedimentation analysis, Stockes rule (ISO 13317-3:2001).

[0066] Optional additives

[0067] Polymer composition according to the present invention can further comprise additives, such as nucleating agent and clarifying agent, stabilizer, releasing agent, plasticizer, antioxidant, lubricant, antistatic agent, crosslinking agent, anti-scratch agent, high-performance filler, pigment and / or colorant, flame retardant, foaming agent, acid scavenger, regeneration additive, antibacterial agent, anti-fog additive, slip additive, anti-caking additive, polymer processing aid etc.These additives are well known in the art.The amount of additive is preferably based on the total amount of polymer composition at the most 5.0wt%, preferably at the most 4.5wt%, preferably at the most 4wt%, more preferably at the most 3.8wt%.The reason for the preferred low amount of additive is that when this amount, additive does not have adverse effects for the performance expected according to polymer composition of the present invention.

[0068] polymer composition

[0069] The polymer composition according to this invention comprises the first heterophasic propylene copolymer (a), the second heterophasic propylene copolymer (b), an ethylene-based elastomer, optionally an inorganic filler and optionally additives, wherein the amount of the first heterophasic propylene copolymer (a) is 23.1 to 73.7 wt%, preferably 28.3 to 54.8 wt%, preferably 32.2 to 44.7 wt%, based on the total amount of the polymer composition, and wherein the amount of the second heterophasic propylene copolymer (b) is 21.2 to 64.5 wt%, preferably 24.5 to 50.1 wt%, preferably 27.2 to 40.1 wt%, based on the total amount of the polymer composition.

[0070] The amount of the ethylene-based elastomer is 16.9-27.6 wt%, more preferably 17.8-25.4 wt%, even more preferably 18.3-23.7 wt%, based on the total amount of the polymer composition.

[0071] The total amount of the first heterophasic propylene copolymer (a), the second heterophasic propylene copolymer (b), the ethylene-based elastomer, optionally the inorganic filler and optionally the additives is preferably at least 95 wt%, preferably at least 97 wt%, preferably at least 98.5 wt%, preferably at most 100 wt%, based on the total amount of the polymer composition.

[0072] The amount of inorganic filler is preferably at most 20 wt%, at most 16 wt%, more preferably at most 12 wt%, based on the total amount of the polymer composition.

[0073] The MFI of the polymer composition is preferably 5-100 dg / min, preferably 10-70 dg / min, more preferably 15-50 dg / min, more preferably 15-25 dg / min, as measured at 230° C. using a 2.16 kg load according to ISO 1133-1:2011. In this preferred MFI range, the polymer composition has an optimal balance between impact properties and processability.

[0074] The polymer composition according to this invention can be prepared e.g. by an extrusion process: the first heterophasic propylene copolymer (a), the ethylene-based elastomer, the second heterophasic propylene copolymer (b), optionally an inorganic filler and optionally additives are melt mixed in an extruder.

[0075] The present invention further relates to a method for preparing an article, preferably an automobile part, more preferably an automobile bumper, comprising the following consecutive steps:

[0076] - providing a polymer composition according to the invention obtained by extrusion;

[0077] - shaping the polymer composition according to the invention into articles, preferably by injection molding.

[0078] The present invention further relates to the use of the polymer composition according to the invention for producing articles, preferably automotive parts, such as automotive interior parts, such as automotive exterior parts, such as automotive bumpers.

[0079] The present invention further relates to an article obtained or obtainable by the process of the present invention, preferably an injection molded article, more preferably an injection molded automotive article, wherein the amount of the polymer composition according to the present invention is at least 95 wt%, preferably at least 98 wt%, based on the total amount of the article.

[0080] The present invention further relates to a vehicle bumper comprising the polymer composition according to the invention, wherein the amount of the polymer composition according to the invention is at least 95 wt%, preferably at least 98 wt%, based on the total amount of the vehicle bumper.

[0081] In order to avoid any confusion, in the context of the present invention, the term "amount" may be understood as "weight"; "melt flow index (MFI)" refers to the same physical property as "melt flow rate (MFR)".

[0082] It should be noted that the present invention relates to all possible combinations of features described herein, preferably in particular those combinations of features present in the claims. It will therefore be understood that all combinations of features relating to the composition according to the invention, all combinations of features relating to the method according to the invention, and all combinations of features relating to the composition according to the invention and of features relating to the method according to the invention are described herein.

[0083] It is further noted that the term "comprising" does not exclude the presence of other elements. However, it is also understood that a description of a product / composition comprising certain components also discloses a product / composition consisting of these components. The advantage of a product / composition consisting of these components may be that it provides a simpler and more economical method for preparing the product / composition. Similarly, it is also understood that a description of a method comprising certain steps also discloses a method consisting of these steps. The advantage of a method consisting of these steps may be that it provides a simpler and more economical method. When values ​​are mentioned for lower and upper limits of parameters, it is also understood that a range resulting from the combination of the lower and upper values ​​is disclosed.

[0084] The invention will now be illustrated by the following examples, without being limited thereto.

[0085] Material

[0086] Polymers A, B and D are based on Innovene TM A method for producing a heterophasic propylene copolymer using a sequential dual reactor setup wherein a polypropylene homopolymer is produced in a first reactor and a propylene-ethylene copolymer is produced in a second reactor.

[0087] The polymerization method's catalyst system consists of three components: a primary catalyst, an external electron donor, and a cocatalyst. The primary catalyst was prepared according to the "Primary Catalyst III" section on page 36 of WO 2016198344. The external electron donor for polymers A and B was di(isopropyl)dimethoxysilane (DiPDMS), while that for polymers C and D was n-propyltriethoxysilane (nPTES). The cocatalyst was triethylaluminum.

[0088] The process conditions for polymers A, B and D are given in Table 1:

[0089] Table 1: Preparation conditions of polymers A, B and D

[0090] polymer A B D R1 Te(℃) 66 66 69.5 R1 Pr (bar) 24 24 24 Al / Ti (mol / mol) 135 135 135 Si / Ti (mol / mol) 10 10 10 R1 H2 / C3(mol / mol) 0.08 0.05 0.065 R1 split (wt%) 80 74 86 R2 Te(℃) 66 57 59 R2 Pr (bar) 24 24 24 R2 H2 / C3(mol / mol) 0.132 0.005 0.0042 R2 C2 / C3 (mol / mol) 0.63 0.33 0.31 R2 split (wt%) 20 26 14

[0091] In Table 1, R1 refers to the first reactor, R2 refers to the second reactor, Te refers to temperature, Pr refers to pressure, Al / Ti is the molar ratio of cocatalyst to main catalyst, Si / Ti is the molar ratio of external donor to main catalyst, H2 / C3 is the molar ratio of hydrogen to propylene, C2 / C3 is the molar ratio of ethylene to propylene, and split is the amount of material produced in R1 or R2, based on the amount of total polymer A or B or D, respectively.

[0092] HDPE 80064 is a type of HDPE commercially available from SABIC under the trade name HDPE M80064S, with a density of 0.964 g / cm 3 (ASTM D792-13) and MFI was 8.0 g / 10 min (ASTM D1238-13, 2.16 kg, 190°C).

[0093] HDPE M200056 is a commercially available HDPE with a density of 0.956 g / cm 3 (ASTM D792-13) and MFI was 20.0 g / 10 min (ASTM D1238-13, 2.16 kg, 190°C).

[0094] LDPE 1922 is a commercially available LDPE from SABIC under the trade name LDPE 1922N0, with a density of 0.919 g / cm 3 (ASTM D792-13) and MFI was 22.0 g / 10 min (ASTM D1238-13, 2.16 kg, 190°C).

[0095] Engage 11527 is a polyolefin elastomer commercially available from Dow with a density of 0.866 g / cm 3 (ASTM D792-13), MFI is 15 g / 10 min (ASTM D1238-13, 2.16 kg, 190°C).

[0096] Engage 8200 is a polyolefin elastomer commercially available from Dow with a density of 0.870 g / cm 3 (ASTM D792-13), MFI is 5.0 g / 10 min (ASTM D1238-13, 2.16 kg, 190° C.) and Shore A hardness is 66 (ASTM D2240-15).

[0097] Talc HTPultra 5c is an ultrafine talc commercially available from IMI FABIC. The talc median particle size (D50) of Talc HTPultra 5c is 0.65 μm, measured according to sedimentation analysis, Stockes rule (ISO 13317-3:2001).

[0098] The additive package consists of 60 wt% color masterbatch, 20 wt% heat and processing stabilizers, 10 wt% UV stabilizers, and 10 wt% processing aids, based on the total amount of the additive package.

[0099] Sample preparation

[0100] Compounding

[0101] The pellets of the examples were prepared by mixing the components of Table 3 in a KraussMaffei Berstorff ZE40A_UTX 43D twin-screw extruder at the following settings: 400 rpm screw speed, 150 kg / h throughput, 38% torque, 235° C. temperature and 13 bar head pressure.

[0102] Sample preparation

[0103] The samples used for the ash content test were pellets obtained during the compounding process. Other samples used for the measurements were prepared by injection molding. The sample dimensions used for the impact resistance and shrinkage measurements are defined in the standard; the sample dimensions used for the gloss measurement were 65 × 65 × 3.2 mm.

[0104] Test Method

[0105] Melt flow index

[0106] Melt flow index (MFI) is measured according to ISO 1133-1:2011 at 230°C and 2.16 kg load.

[0107] The weight percentage of xylene soluble fraction (CXS) and the weight percentage of xylene insoluble fraction (CXI)

[0108] The weight percentage of xylene soluble fraction (CXS) of the heterophasic propylene copolymer is determined according to ISO 16152: 2005. The weight percentage of xylene insoluble fraction (CXI) of the heterophasic propylene copolymer is calculated using the following equation:

[0109] CXI=100wt%-CXS

[0110] Both the xylene soluble fraction and the xylene insoluble fraction (CXS and CXI) obtained in this test are used in the intrinsic viscosity (IV) test.

[0111] Intrinsic viscosity (IV)

[0112] The intrinsic viscosity (IV) of CXS and CXI was measured in decalin at 135°C according to ISO 1628-1:2009 and ISO 1628-3:2010, respectively.

[0113] impact resistance

[0114] Impact resistance was measured according to Izod ISO 180:2000 at 23°C and 0°C.

[0115] Tensile modulus

[0116] The tensile modulus is measured at 23°C according to ISO 527-1:2012.

[0117] Glossiness

[0118] Gloss at 20° and 60° is measured according to ISO 2813:2014.

[0119] Ash content

[0120] The ash content is determined according to ISO 3451-1:2019 (4h, 600°C).

[0121] Shrinkage

[0122] The average shrinkage was measured 24 h after injection according to ISO 294-4:2018, with the conditioning temperature being 23°C.

[0123] result

[0124] Table 2. Properties of polymers A, B, and D

[0125] Polymer A Polymer B Polymer D MFI (g / 10min) 40 14 77 Weight fraction of matrix (wt%) 80 74 86 Matrix MFI (g / 10min) 75 85 230 CSX (wt%) 18 22 14 <![CDATA[IV CXS (dl / g)]]> 2.2 4.0 5.3 <![CDATA[IV CXI (dl / g)]]> 1.3 1.4 1.3 Reactor level yes yes yes

[0126] Table 3. Performance of PPc

[0127] CE1 CE2 CE3 CE4 IE1 IE2 CE5 CE6 CE7 CE8 Polymer A (wt%) 35.6 20 45.6 40.6 35.6 40.6 40.6 40.6 40.6 Polymer B (wt%) 30.6 55.6 30 30 30 30 30 30 30 Polymer D (wt%) 30 35 Engage11527 (wt%) 20 HDPE M200056 (wt%) 20 LDPE 1922 (wt%) 20 Engage8200 (wt%) 20 20 15 15 20 20 HDPE M80064 (wt%) 20 Talc HTPultra 5c (wt%) 10 10 5 5 5 10 5 5 5 5 Additive package (wt%) 4.4 4.4 4.4 4.4 4.4 4.4 4.4 4.4 4.4 4.4 MFI (dg / min) 34.7 25 17.6 22.7 20.9 19.8 21.7 23.6 22.7 24 <![CDATA[23 °C impact resistance (kJ / m 2 )]]> 43.7 51.3 54.2 48.2 51.3 52.3 28.5 50 13.3 8.9 <![CDATA[Impact resistance at 0℃ (kJ / m 2 )]]> 17.7 45.3 48.2 22.2 45.2 43.7 8.6 41.5 7.2 5.2 20° glossiness 52.1 51.6 49.4 47.6 57.6 56.2 27.7 45.4 48.2 44.9 60° glossiness 77.1 77.1 76.4 75 80.5 79.5 57.2 72.5 73.8 71.8 Average shrinkage (%) 0.86 0.95 1.14 1.06 0.91 0.74 1.33 0.94 1.24 1.33

[0128] According to the information in Table 3, the polymer compositions of the invention exemplified by IE1 and 2 exhibit high gloss (>55 at 20°) while having shrinkage values ​​lower than 0.93 and maintaining the same level of impact resistance.

Claims

1. A polymer composition comprising a first heterophasic propylene copolymer (a), a second heterophasic propylene copolymer (b) and an ethylene-based elastomer, wherein the amount of the first heterophasic propylene copolymer (a) is 28.3 to 54.8 wt%, based on the total amount of the polymer composition, wherein the amount of the second heterophasic propylene copolymer (b) is 24.5 to 50.1 wt%, based on the total amount of the polymer composition, wherein the amount of the ethylene-based elastomer is 16.9 to 27.6 wt%, based on the total amount of the polymer composition, wherein the first heterophasic propylene copolymer (a) comprises: 65 to 81 wt% of a propylene polymer (a1), 19 to 35 wt% of an ethylene-α-olefin copolymer (a2), wherein the α-olefin moiety in the ethylene-α-olefin copolymer (a2) is derived from at least one α-olefin having 3 to 20 carbon atoms, wherein the intrinsic viscosity of the xylene soluble fraction of the first heterophasic propylene copolymer (a) is from 1.7 to 3.1 dl / g, measured according to ISO 1628-1: 2009; wherein the MFI of the first heterophasic propylene copolymer (a) is from 23 to 65 dg / min, measured according to ISO 1133-1: 2011 at 230°C and 2.16 kg load, wherein the xylene soluble fraction of the second heterophasic propylene copolymer (b) is 12 to 27 wt%, determined according to ISO 16152: 2005, based on the total amount of the second heterophasic propylene copolymer (b); wherein the intrinsic viscosity of the xylene soluble fraction of the second heterophasic propylene copolymer (b) is 2.9 to 4.6 dl / g, measured according to ISO 1628-1: 2009 in decalin at 135 °C; wherein the MFI of the second heterophasic propylene copolymer (b) is 10.3 to 39 dg / min, measured according to ISO 1133-1: 2011 at 230 °C and 2.16 kg load, The density of the ethylene-based elastomer is 0.868-0.943 g / cm 3 and wherein the MFI of the ethylene-based elastomer is 0.20-20.0 dg / min as measured at 190°C using a 2.16 kg load in accordance with ASTM D1238-13.

2. The polymer composition according to claim 1 , wherein the second heterophasic propylene copolymer (b) has an MFI of 12.5 to 27 dg / min, determined according to ISO 1133-1: 2011 at 230°C and 2.16 kg load.

3. Polymer composition according to anyone of claims 1 to 2, wherein the amount of first heterophasic propylene copolymer (a) is 32.2 to 44.7 wt%, based on the total amount of the polymer composition.

4. The polymer composition according to anyone of claims 1 to 2, wherein the amount of the second heterophasic propylene copolymer (b) is 27.2 to 40.1 wt.-%, based on the total polymer composition.

5. Polymer composition according to anyone of claims 1 to 2, wherein the first heterophasic propylene copolymer (a) has an MFI of 30 to 50 dg / min, determined according to ISO 1133-1: 2011 at 230°C and 2.16 kg load.

6. The polymer composition of any one of claims 1 to 2, wherein the MFI of the ethylene-based elastomer is 1.3-14.3 dg / min, as measured at 190°C using a 2.16 kg load according to ASTM D1238-13.

7. The polymer composition of any one of claims 1 to 2, wherein the MFI of the ethylene-based elastomer is 2.6-7.2 dg / min, as measured at 190°C using a 2.16 kg load according to ASTM D1238-13.

8. The polymer composition according to any one of claims 1 to 2, wherein the ethylene-based elastomer is an ethylene-butene copolymer or / and an ethylene-octene copolymer.

9. The polymer composition of any one of claims 1 to 2, wherein the ethylene-based elastomer is an ethylene-octene copolymer.

10. The polymer composition according to any one of claims 1 to 2, wherein the polymer composition has an MFI of 5-100 dg / min, measured according to ISO 1133-1: 2011 using a 2.16 kg load at 230°C.

11. The polymer composition according to any one of claims 1 to 2, wherein the polymer composition has an MFI of 10-70 dg / min, measured according to ISO 1133-1: 2011 using a 2.16 kg load at 230°C.

12. The polymer composition according to any one of claims 1 to 2, wherein the polymer composition has an MFI of 15-50 dg / min, measured according to ISO 1133-1: 2011 using a 2.16 kg load at 230°C.

13. The polymer composition according to any one of claims 1 to 2, wherein the polymer composition has an MFI of 15-25 dg / min, measured according to ISO 1133-1: 2011 using a 2.16 kg load at 230°C.

14. The polymer composition according to claim 1, wherein the polymer composition further comprises an inorganic filler, wherein the amount of the inorganic filler is up to 20 wt% based on the total amount of the polymer composition.

15. The polymer composition according to claim 14, wherein the amount of the inorganic filler is at most 16 wt%, based on the total amount of the polymer composition.

16. The polymer composition according to claim 14, wherein the amount of the inorganic filler is at most 12 wt%, based on the total amount of the polymer composition.

17. The polymer composition according to any one of claims 14 to 16, wherein the inorganic filler is talc.

18. Polymer composition according to anyone of claims 14 to 16, wherein the polymer composition further comprises additives, wherein the total amount of the first heterophasic propylene copolymer (a), the second heterophasic propylene copolymer (b), the ethylene-based elastomer, the inorganic filler and the additives is at least 95 wt-% and at most 100 wt-%, based on the total amount of the polymer composition.

19. Polymer composition according to claim 18, wherein the total amount of the first heterophasic propylene copolymer (a), the second heterophasic propylene copolymer (b), the ethylene-based elastomer, the inorganic filler and additives is at least 97 wt-% and at most 100 wt-%, based on the total amount of the polymer composition.

20. The polymer composition according to claim 18, wherein the total amount of the first heterophasic propylene copolymer (a), the second heterophasic propylene copolymer (b), the ethylene-based elastomer, the inorganic filler and additives is at least 98.5 wt-% and at most 100 wt-%, based on the total amount of the polymer composition.

21. An automobile bumper comprising the polymer composition according to any one of claims 1 to 20, wherein the amount of the polymer composition is at least 95 wt%, based on the total amount of the automobile bumper.

22. An automobile bumper comprising the polymer composition according to any one of claims 1 to 20, wherein the amount of the polymer composition is at least 98 wt%, based on the total amount of the automobile bumper.

23. A method for preparing an article, comprising the following steps in sequence: - providing a polymer composition according to any one of claims 1 to 20 obtained by extrusion; - forming the polymer composition according to any one of claims 1 to 20 into an article.

24. The method of claim 23, wherein the polymer composition is formed into an article by injection molding.

25. An article obtained by the method according to claim 23 or 24, wherein the article is an automotive part.

26. The article of claim 25, wherein the article is an automobile bumper.