Composition for luggage case

Abstract

The present invention relates to a composition comprising (A1) a heterophasic propylene copolymer, (A2) a post consumer recovery heterophasic propylene copolymer, (B) a propylene homopolymer and (C) a polyolefin-based elastomer. The composition of the present invention has a combination of good mechanical properties for luggage applications and achieves good environmental benefits.

Description

Technical Field

[0001] The present invention relates to a composition comprising a post-consumer recycled propylene-based polymer, a method for obtaining such a composition, and an article comprising such a composition, particularly a suitcase. Background Technology

[0002] Propylene-based polymers are used in many applications, including luggage. Propylene-based polymers can be propylene homopolymers, single-phase propylene copolymers, or multiphase propylene copolymers.

[0003] Suitcases are subjected to relatively harsh conditions during use, especially larger suitcases checked in during flights. Therefore, tests are conducted to determine whether a suitcase has sufficient performance characteristics, such as stress resistance to whitening, gloss, impact strength, and tensile properties.

[0004] EP3674363 discloses a baggage made of a polypropylene modified material comprising 10-40 wt% homopolymer, 35-60 wt% polypropylene copolymer, 5-15 wt% polyolefin elastomer, 10-20 wt% polyethylene, 0.03-0.08 wt% nucleating agent, 0.03-0.06 wt% antioxidant, and 2-6 wt% flow modifier.

[0005] Virgin plastics refer to new, direct resins produced using natural gas or crude oil, containing no recycled materials. Post-consumer recycled (PCR) materials, on the other hand, refer to materials made from items recycled by consumers. Typically, recyclable items such as plastics, metals, and cardboard / paper are collected by local recycling programs and transported to facilities for sorting based on material type. Recycling packages are then purchased and sent to various recyclers for use in various finished products. Using PCR components (i.e., recycled materials) in products such as luggage brings environmental benefits in terms of carbon reduction and resource efficiency. Simultaneously, it reduces the demand for virgin raw materials and extends the lifespan of materials. Incorporating PCR into production supports the development of a circular economy.

[0006] Methods for recycling polypropylene are known in the art, such as WO2012117250, US9670344, and WO2014040634. However, recycled polypropylene typically suffers from performance degradation compared to virgin polypropylene. A typical solution to this problem is to dilute the recycled polypropylene in virgin polypropylene to obtain polypropylene blends, but polypropylene blends often also suffer from the degradation of recycled polypropylene. Summary of the Invention

[0007] The object of this invention is to provide a composition that, by using a certain type and amount of PCR material, possesses good mechanical properties for manufacturing suitcases, while also achieving good environmental benefits.

[0008] Therefore, the present invention provides a composition comprising:

[0009] (A1) Multiphase propylene copolymer,

[0010] (A2) Post-consumption recovery of multiphase propylene copolymers

[0011] (B) Propylene homopolymer, and

[0012] (C) Polyolefin-based elastomers

[0013] in

[0014] (A1) The multiphase propylene copolymer has a melt flow index of 5.0-50 g / 10 min, measured at 230°C with a load of 2.16 kg, according to ISO 1133-1:2011.

[0015] (A2) Post-consumer recycled multiphase propylene copolymers have a melt flow index of 5.0-50 g / 10 min at 230°C with a load of 2.16 kg, a ash content of 0.5-3.5 wt%, and a gloss of 55-70 at 20°C as measured according to ISO 1133-1:2011.

[0016] In one aspect of the invention, the weight ratio of (A2):(A1) is 1-3.

[0017] In one aspect of the invention, relative to the total weight of the composition,

[0018] The amount of (A1) is 20-30% by weight, preferably 23-27% by weight.

[0019] The amount of (A2) is 40-65% by weight, preferably 50-55% by weight.

[0020] (B) is in the amount of 5-30% by weight, preferably 10-20% by weight, and

[0021] The amount of (C) is 1-15% by weight, preferably 5-10% by weight.

[0022] In one aspect of the invention, (A1) has a melt flow index of 10-40 g / 10 min, more preferably 20-35 g / 10 min, as measured according to ISO 1133-1:2011 at 230°C with a load of 2.16 kg.

[0023] In one aspect of the invention, (A2) has a melt flow index of 10-40 g / 10 min, more preferably 20-35 g / 10 min, as measured according to ISO 1133-1:2011 at 230°C with a load of 2.16 kg.

[0024] In one aspect of the invention, (A1) comprises a propylene-based matrix (a1) and a dispersed ethylene-α-olefin copolymer (a2), wherein the amount of (a2) in (A1) is 2.0-40% by weight, for example at least 5.0% by weight, at least 10.0% by weight, or at least 15.0% by weight, and / or at most 35% by weight, at most 30% by weight, or at most 25% by weight.

[0025] In one aspect of the invention, (A2) comprises (a1) a propylene-based matrix and (a2) a dispersed ethylene-α-olefin copolymer, wherein the amount of (a2) in (A2) is 2.0-40% by weight, for example at least 5.0% by weight, at least 10.0% by weight, or at least 15.0% by weight, and / or at most 35% by weight, at most 30% by weight, or at most 25% by weight.

[0026] In one aspect of the invention, the total amount of (a2) and (C) is 20-25% by weight relative to the total composition.

[0027] In one aspect of the invention, the amount of ethylene monomer units in the (a2) dispersed ethylene-α-olefin copolymer of the (A2) post-consumption recovered multiphase propylene copolymer is 30-44% by weight, preferably 35-42% by weight.

[0028] In one aspect of the invention, (A2) has a strength of 6.0-10.0 kJ / m³ measured at 23°C according to ISO 179. 2 The preferred value is 6.5-8.0 kJ / m³. 2 Impact strength of a simply supported beam.

[0029] In one aspect of the invention, (B) has a melt flow index of 25-100 dg / min, for example at least 30 dg / min, at least 40 dg / min, at least 45 dg / min or at least 50 dg / min, and / or for example at most 90 dg / min, at most 80 dg / min, at most 75 dg / min, at most 70 dg / min, as measured according to ISO 1133-1:2011 at 230°C with a load of 2.16 kg, and / or at most 90 dg / min, at most 80 dg / min, at most 75 dg / min, at most 70 dg / min.

[0030] In one aspect of the invention, (C) is a copolymer of ethylene and an α-olefin comonomer having 4-10 carbon atoms, preferably an ethylene-1-octene copolymer.

[0031] In one aspect of the invention, (C) has a melt flow index of 5-50 dg / min, preferably 10-45 dg / min, more preferably 15-40 dg / min, and more preferably 25-35 dg / min, as measured according to ASTM D1238 at a temperature of 190°C with a load of 2.16 kg.

[0032] In one aspect of the invention, the composition has a melt flow index of 15-60 dg / min, preferably 20-50 dg / min, more preferably 25-40 dg / min, as measured according to ISO 1133-1:2011 at 230°C with a load of 2.16 kg.

[0033] The present invention also provides a method for preparing a composition comprising melt mixing (A1), (A2), (B), (C) and optional (D) additives.

[0034] The present invention also provides articles obtained by injection molding the compositions of the present invention. The articles are preferably suitcases. Preferably, the suitcases have a capacity of 100-130 L, for example 105-120 L.

[0035] According to the present invention, a multiphase propylene copolymer is mixed with a PCR multiphase propylene copolymer and further mixed with a propylene homopolymer and a polyolefin-based elastomer. The resulting composition has a combination of good mechanical properties for manufacturing luggage, such as good stress whitening resistance, gloss and impact strength, as well as good environmental benefits.

[0036] (A1) Multiphase propylene copolymer

[0037] Multiphase propylene copolymers are virgin materials typically prepared in one or more reactors by polymerizing propylene in the presence of a catalyst and subsequently polymerizing an ethylene-α-olefin mixture. The resulting polymeric material is multiphase, but its specific morphology usually depends on the preparation method and the proportion of monomers used.

[0038] The multiphase propylene copolymers used in this invention can be produced using any conventional techniques known to those skilled in the art, such as multi-stage process polymerization, including bulk polymerization, gas-phase polymerization, slurry polymerization, solution polymerization, or any combination thereof. Any conventional catalyst system can be used, such as Ziegler-Natta or metallocene. Such techniques and catalysts are described, for example, in WO06 / 010414, Ser van der Ven's *Polypropylene and other Polyolefins*, *Studies in Polymer Science 7*, Elsevier 1990, WO06 / 010414, US4399054, and US4472524.

[0039] Preferably, a Ziegler-Natta catalyst is used to produce the multiphase propylene copolymer.

[0040] Multiphase propylene copolymers can be prepared by methods including the following:

[0041] - Propylene and optionally ethylene and / or α-olefins are polymerized in the presence of a catalyst system to obtain a propylene-based matrix, and

[0042] Subsequently, ethylene and α-olefins are polymerized in a propylene-based matrix in the presence of a catalyst system to obtain dispersed ethylene-α-olefin copolymers. Preferably, these steps are carried out in separate reactors. The catalyst systems for the first and second steps can be different or the same.

[0043] The multiphase propylene copolymer of the present invention comprises a propylene-based matrix and a dispersed ethylene-α-olefin copolymer. The propylene-based matrix typically forms a continuous phase in the multiphase propylene copolymer. The amount of the propylene-based matrix and the dispersed ethylene-α-olefin copolymer can be determined by… 13 C-NMR determination is known in the art.

[0044] The propylene-based matrix consists of propylene homopolymers and / or propylene copolymers, wherein the propylene copolymers consist of at least 90% by weight of propylene monomer units and at most 10% by weight of comonomer units selected from ethylene monomer units and α-olefin monomer units having 4-10 carbon atoms, based on the total weight of the propylene-based matrix, for example, at least 95% by weight of propylene monomer units and at most 5% by weight of comonomer units.

[0045] Preferably, the comonomers in the propylene copolymer based on a propylene matrix are selected from ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, and 1-octene, with ethylene being the most preferred.

[0046] Preferably, the propylene-based matrix is ​​composed of propylene homopolymer. The fact that the propylene-based matrix is ​​composed of propylene homopolymer is advantageous because it achieves higher rigidity compared to cases where the propylene-based matrix is ​​a propylene-α-olefin copolymer.

[0047] The melt flow index (MFI) of the propylene-based matrix (before the multiphase propylene copolymer is incorporated into the composition of the present invention), as measured according to ISO 1133-1:2011 (2.16 kg / 230°C). PPIt may be, for example, at least 0.1 dg / min, at least 0.2 dg / min, at least 0.3 dg / min, at least 0.5 dg / min and / or, for example, at most 20 dg / min, at most 10 dg / min, at most 5.0 dg / min, at most 3.0 dg / min, at most 1.0 dg / min.

[0048] Preferably, the propylene-based matrix is ​​present in an amount of 60-98% by weight, for example, up to 97% by weight, up to 96% by weight, up to 95% by weight, up to 93% by weight, or up to 91% by weight, based on the total multiphase propylene copolymer. Preferably, the propylene-based matrix is ​​present in an amount of at least 70% by weight, more preferably at least 75% by weight, for example, at least 80% by weight, at least 85% by weight, at least 87% by weight, or at least 90% by weight, based on the total multiphase propylene copolymer.

[0049] The propylene-based matrix is ​​preferably semi-crystalline, meaning it is neither 100% amorphous nor 100% crystalline. For example, the propylene-based matrix is ​​at least 40% crystalline, such as at least 50%, such as at least 60% crystalline, and / or, such as at most 80% crystalline, such as at most 70% crystalline. For example, the propylene-based matrix has a crystallinity of 60%-70%. For the purposes of this invention, the crystallinity of the propylene-based matrix was measured using differential scanning calorimetry (DSC) according to ISO 11357-1 and ISO 11357-3 (1997), with a scan rate of 10 °C / min, a sample size of 5 mg, and a second heating curve using 207.1 J / g as the theoretical standard for 100% crystalline material.

[0050] In addition to the propylene-based matrix, multiphase propylene copolymers also contain dispersed ethylene-α-olefin copolymers. These dispersed ethylene-α-olefin copolymers are also referred to herein as the 'dispersed phase'. The dispersed phase is embedded in the multiphase propylene copolymer in a discontinuous form. The particle size of the dispersed phase is typically in the range of 0.05–2.0 micrometers and can be determined by transmission electron microscopy (TEM).

[0051] The amount of ethylene-α-olefin copolymer dispersed in the multiphase propylene copolymer may sometimes be referred to herein as RC. Preferably, RC is 2.0-40% by weight, for example at least 5.0% by weight, at least 10.0% by weight, or at least 15.0% by weight, and / or at most 35% by weight, at most 30% by weight, or at most 25% by weight, for example 18% by weight, 20% by weight, or 22% by weight.

[0052] The amount of ethylene monomer units in an ethylene-α-olefin copolymer dispersed in a multiphase propylene copolymer may sometimes be referred to herein as RCC2. Preferably, RCC2 is 30-70% by weight, for example at least 35% by weight, at least 40% by weight, or at least 45% by weight, and / or at most 65% by weight, at most 60% by weight, or at most 55% by weight, for example 48% by weight, 50% by weight, or 52% by weight.

[0053] The α-olefin in the ethylene-α-olefin copolymer is preferably selected from α-olefins having 3-8 carbon atoms. Suitable examples of α-olefins having 3-8 carbon atoms include, but are not limited to, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, and 1-octene. More preferably, the α-olefin in the ethylene-α-olefin copolymer is selected from α-olefins having 3-4 carbon atoms and any mixture thereof, and more preferably, the α-olefin is propylene, in which case the ethylene-α-olefin copolymer is an ethylene-propylene copolymer.

[0054] The MFI of the dispersed ethylene α-olefin copolymer (before the multiphase propylene copolymer is incorporated into the composition of the present invention), i.e., the MFI rubber, may be, for example, at least 0.001 dg / min, at least 0.03 dg / min, or at least 0.05 dg / min, and / or, for example, at most 0.1 dg / min or 0.01 dg / min. The MFI rubber is calculated according to the following formula:

[0055]

[0056] Where MFI (Multiphase) is the MFI (dg / min) of the multiphase propylene copolymer measured according to ISO 1133-1:2011 (2.16 kg / 230℃), MFI (Matrix) is the MFI (dg / min) of the propylene-based matrix measured according to ISO 1133-1:2011 (2.16 kg / 230℃), matrix content is the fraction of the propylene-based matrix in the multiphase propylene copolymer, and rubber content is the fraction of the dispersed ethylene-α-olefin copolymer in the multiphase propylene copolymer. The sum of matrix content and rubber content is 1. To avoid any ambiguity, Log in the formula means log 10 .

[0057] In the multiphase propylene copolymer in the composition of the present invention, the sum of the total weight of the propylene-based matrix and the total weight of the dispersed ethylene-α-olefin copolymer is 100% by weight of the multiphase propylene copolymer.

[0058] Preferably, the multiphase propylene copolymer has 2.0-40% by weight, for example 9.0-25% by weight, of a portion soluble in p-xylene at 25°C, as measured according to ISO 16152:2005.

[0059] Preferably, the amount of ethylene monomer units in the multiphase propylene copolymer (sometimes referred to as TC2, TC2 = RC × RCC2) is 5.0-20% by weight, for example 8.0-15% by weight, based on the multiphase propylene copolymer.

[0060] Preferably, the MFI of the multiphase propylene copolymer is 5.0-50 g / 10 min as measured according to ISO 1133-1:2011 (230°C / 2.16 kg), for example at least 10 dg / min, at least 15 dg / min, at least 20 dg / min and / or at most 45 dg / min, at most 40 dg / min or at most 35 dg / min. This particularly results in good processability of the compositions according to the invention.

[0061] Preferably, in the multiphase propylene copolymer according to the invention, the comonomer in the propylene-α-olefin copolymer is selected from the group consisting of ethylene and α-olefins having 4-10 carbon atoms, and the α-olefin in the ethylene-α-olefin copolymer is selected from the group consisting of α-olefins having 3-8 carbon atoms. Most preferably, in the multiphase propylene copolymer according to the invention, the comonomer in the propylene-α-olefin copolymer is ethylene and the α-olefin in the ethylene-α-olefin copolymer is propylene.

[0062] Preferably, the amount of (A1) multiphase propylene copolymer relative to the composition of the present invention is 20-30% by weight, preferably 23-27% by weight, for example 25% by weight or 26% by weight.

[0063] (A2) Post-consumption recovery of multiphase propylene copolymers

[0064] The recycled materials used in this invention are obtained by processing waste plastic materials derived from post-consumer waste through known methods involving, for example, washing, sorting, and / or grinding. In particular, the recycled materials used in this invention are post-consumer recycled multiphase propylene copolymers.

[0065] The post-consumer recycled multiphase propylene copolymer of the present invention consists of a propylene-based matrix and dispersed ethylene-α-olefin copolymers. Generally, the post-consumer recycled multiphase propylene copolymer (PCR HECO) has properties similar to the aforementioned primary multiphase propylene copolymers, with one substantial difference being the presence of a certain amount of ash content.

[0066] The propylene-based matrix consists of propylene homopolymers and / or propylene copolymers, said propylene copolymers consisting of at least 90% by weight of propylene monomer units and at most 10% by weight of comonomer units selected from ethylene monomer units and α-olefin monomer units having 4-10 carbon atoms, for example, consisting of at least 95% by weight of propylene monomer units and at most 5% by weight of comonomer units, based on the total weight of the propylene-based matrix.

[0067] Preferably, the comonomers in the propylene copolymer based on a propylene matrix are selected from ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, and 1-octene, with ethylene being the most preferred.

[0068] Preferably, the propylene-based matrix is ​​composed of propylene homopolymer.

[0069] PCR HECO has an ash content of 0.5%-3.5% by weight, preferably at least 0.8% by weight or at least 1.0% by weight, as determined by ISO 3451, and at most 3.0% by weight or at most 2.5% by weight, for example 1.2% by weight or 1.5% by weight.

[0070] Preferably, the MFI of PCR HECO is 5.0-50 g / 10 min, for example at least 10 dg / min, at least 15 dg / min, at least 20 dg / min and / or at most 45 dg / min, at most 40 dg / min or at most 35 dg / min, as measured according to ISO 1133-1:2011 (230℃ / 2.16 kg).

[0071] Preferably, the RC of PCR HECO is 2.0-40% by weight, for example at least 5.0% by weight, at least 10.0% by weight, or at least 15.0% by weight, and / or at most 35% by weight, at most 30% by weight, or at most 25% by weight, for example 18% by weight, 20% by weight, or 22% by weight.

[0072] Preferably, the RCC2 of PCR HECO is 30-44% by weight, preferably 35-42% by weight, for example 38% by weight or 40% by weight.

[0073] Preferably, the PCR HECO has a strength of 6.0-10.0 kJ / m³ as measured at 23°C according to ISO 179. 2 The preferred concentration is 6.5-8.0 kJ / m³. 2 For example, 6.8 or 7.0 kJ / m 2 Impact strength of a simply supported beam.

[0074] Preferably, the amount of PCR HECO relative to the composition of the present invention is 40-65% by weight, preferably 50-55% by weight, for example 52% by weight or 54% by weight.

[0075] Preferably, the amount of PCR HECO is 1-3 times the amount of the multiphase propylene copolymer, that is, the weight ratio of (A2):(A1) is 1-3, for example 1.5, 2.0 or 2.5.

[0076] (B) Propylene homopolymer

[0077] The compositions of the present invention comprise (B) a propylene homopolymer. Preferably, (B) has a higher melt flow index (MFI) measured according to ISO 1133-1:2011 (2.16 kg / 230°C) than (A1) measured according to ISO 1133-1:2011 (2.16 kg / 230°C). This particularly results in good processability of the compositions according to the present invention.

[0078] The propylene homopolymer may have a melt flow index (MFI) of 25 to 100 dg / min, such as at least 30 dg / min, at least 40 dg / min, at least 45 dg / min or at least 50 dg / min, and / or, such as at most 90 dg / min, at most 80 dg / min, at most 75 dg / min or at most 70 dg / min, as measured according to ISO 1133-1:2011 (2.16 kg / 230 °C).

[0079] Preferably, the amount of (B) propylene homopolymer relative to the composition of the present invention is 5-30% by weight, more preferably 10-20% by weight.

[0080] (C) Polyolefin-based elastomers

[0081] The compositions of the present invention comprise a polyolefin-based elastomer. Preferably, the polyolefin-based elastomer is a copolymer of ethylene and an α-olefin comonomer having 4-10 carbon atoms. Using such an ethylene copolymer results in a better flexural modulus of the compositions according to the present invention compared to using an ethylene-propylene copolymer as the polyolefin-based elastomer.

[0082] The α-olefin comonomer in the elastomer preferably has 4-8 carbon atoms, and is more preferably a noncyclic monoolefin, such as 1-butene, 1-pentene, 1-hexene, 1-octene, or 4-methyl-1-pentene. Most preferably, the elastomer is an ethylene-1-octene copolymer.

[0083] Preferably, the elastomer has a strength of 0.850-0.890 g / cm³. 3The density of the first elastomer is preferably 0.855-0.880 g / cm³. 3 0.860-0.870 g / cm³ 3 Or 0.865-0.870 g / cm³ 3 .

[0084] Elastomers can be prepared using methods known in the art, for example, by using a single-site catalyst, i.e., a catalyst in which the transition metal component is an organometallic compound and at least one ligand has a cyclopentadienyl anionic structure, the ligand being coordinated to the transition metal cation via said anionic structure. This type of catalyst is also known as a "metallocene" catalyst. Metallocene catalysts are described, for example, in U.S. Patent Nos. 5,017,714 and 5,324,820. Elastomers can also be prepared using conventional types of multiphase, multisite Ziegler-Natta catalysts.

[0085] The elastomer has a melt flow index of 5-50 dg / min, preferably 10-45 dg / min, more preferably 15-40 dg / min, and even more preferably 25-35 dg / min, as measured according to ASTM D1238 at 190°C under a 2.16 kg load. This results in a good combination of mechanical properties suitable for manufacturing luggage, such as good resistance to stress whitening, gloss, impact strength, and tensile properties.

[0086] Preferably, the amount of elastomer (C) relative to the composition of the present invention is 1-15% by weight, 2-13% by weight, 3-11% by weight, or 5-10% by weight. This results in a suitable total rubber content, together with the dispersed phase of the multiphase propylene copolymer, achieving the good mechanical properties of the composition according to the present invention.

[0087] The total amount of (a2) (including both (a2) in (A1) and (a2) in (A2)) and (C) relative to the total composition is 20.0-25.0% by weight, for example 21% by weight, 22% by weight, 23% by weight or 24% by weight.

[0088] (D) Additives

[0089] The compositions according to the invention may optionally contain additives. Additives may include: nucleating agents; stabilizers, such as heat stabilizers, antioxidants, UV stabilizers; colorants, such as pigments and dyes; clarifying agents; surface tension modifiers; lubricants; flame retardants; mold release agents; flow improvers; plasticizers; antistatic agents; and foaming agents.

[0090] Technicians can easily select any suitable combination and amount of additives without requiring extensive experimentation. The amount of additives depends on their type and function and is typically from 0 to 10% by weight. The amount of additives may be, for example, from about 0.1 to about 5% by weight, from about 1 to about 4% by weight, or from 1.5 to about 3% by weight based on the total composition. The total amount of (A), (B), (C), and (D) should be 100% by weight. Preferably, components (A), (B), and (C) total at least 90%, at least 95%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or 100% by weight of the total composition.

[0091] Composition

[0092] The composition has a melt flow index of 15-60 dg / min, preferably 20-50 dg / min, more preferably 25-40 dg / min, as measured according to ISO 1133-1:2011 at 230°C with a load of 2.16 kg.

[0093] Other aspects

[0094] The compositions of the present invention can be obtained by methods including melt mixing (A1), (A2), (B), (C) and optionally (D) using any suitable means. Therefore, the present invention further relates to a method for preparing compositions according to the invention, including melt mixing (A1), (A2), (B), (C) and optionally (D).

[0095] Preferably, the compositions of the present invention are formulated to allow for easy processing into shaped articles in subsequent steps, such as pellets or granules. The compositions may be mixtures of different particles or pellets, such as blends of (A1), (A2), (B), (C) and masterbatches of additives. Preferably, the compositions of the present invention are in pellet or granule form, such as by mixing all components in equipment such as an extruder; the advantage is that the compositions have a uniform and well-defined additive concentration.

[0096] Melt mixing can be performed using techniques known to those skilled in the art, for example, in an extruder. Typically, in the method of the present invention, melt mixing is carried out at a temperature of 200-260°C.

[0097] When using an extruder, the appropriate conditions for melt mixing, such as temperature, pressure, shear rate, screw speed, and screw design, are known to those skilled in the art.

[0098] The compositions according to the invention can be processed by known processing methods, particularly injection molding.

[0099] The present invention further relates to an article comprising a composition according to the invention, particularly a suitcase. Specifically, the present invention relates to an injection-molded article comprising or made from a composition according to the invention, particularly a suitcase.

[0100] Specifically, the present invention relates to an injection-molded article comprising or made of a composition according to the invention, particularly a suitcase having a capacity of 100-130 L, for example 105-120 L.

[0101] It should be noted that the present invention relates to the subject matter defined by the independent claims alone or in combination with any possible combination of features described herein, preferably, in particular, those combinations of features presented in the claims. Therefore, it is to be understood that all combinations of features relating to compositions according to the invention, all combinations of features relating to methods according to the invention, and all combinations of features relating to compositions according to the invention and features relating to methods according to the invention are described herein.

[0102] It should be further noted that the terms 'comprising,' 'including,' and 'containing' do not exclude the presence of other elements. However, it should also be understood that descriptions of products / compositions comprising certain components also disclose products / compositions composed of those components. Products / compositions composed of these components may be advantageous because they provide a simpler and more economical method for preparing the product / composition. Similarly, it should be understood that descriptions of methods including certain steps also disclose methods composed of those steps. Methods composed of these steps may be advantageous because they provide a simpler and more economical method.

[0103] When a value is mentioned for the lower and upper limits of a parameter, it is also understood to mean that the range of combinations of the lower and upper limits is disclosed.

[0104] The present invention will now be illustrated by means of the following embodiments, but the present invention is not limited thereto. Example

[0105] Material

[0106] ICP1: Multiphase propylene copolymer, consisting of a matrix of propylene homopolymer and a dispersed phase (RC) of 22.3 wt% ethylene-propylene copolymer, having an ethylene content of 11 wt% (TC2) and an MFI of 29 dg / min (ISO 1133-1:2011 at 230 °C with a 2.16 kg load).

[0107] ICP2: Multiphase propylene copolymer, consisting of a matrix of propylene homopolymer and a dispersed phase (RC) of 22.3 wt% ethylene-propylene copolymer, with an ethylene content of 11 wt% (TC2) and an MFI of 3.5 dg / min (ISO 1133-1:2011 at 230 °C with a loading of 2.16 kg).

[0108] PCR: Post-consumption recovery of multiphase propylene copolymers, consisting of a propylene homopolymer matrix and an ethylene-propylene copolymer dispersed phase, with the following physical parameters:

[0109] homoPP1: a propylene homopolymer with an MFI of 60 dg / min (ISO1133-1:2011 at 230°C with a load of 2.16 kg).

[0110] homoPP2: a propylene homopolymer with an MFI of 12 dg / min (ISO1133-1:2011 at 230°C with a load of 2.16 kg).

[0111] homoPP3: a propylene homopolymer with an MFI of 3.1 dg / min (ISO 1133-1:2011 at 230°C with a load of 2.16 kg).

[0112] HDPE1: High-density polyethylene with an MFI of 20 dg / min (ASTM D1238 at 190°C, 2.16 kg) and 0.956 g / cm³ at 23°C. 3 The density (ASTM D1505).

[0113] POE1: A copolymer of ethylene and 1-octene, with an MFI of 30.0 dg / min (ASTM D1238 at 190°C with a 2.16 kg load) and 0.868 g / cm³. 3 The density (ASTM D792).

[0114] POE2: A copolymer of ethylene and 1-octene, with an MFI of 5.0 dg / min (ASTM D1238 at 190°C with a 2.16 kg load) and 0.868 g / cm³. 3 The density (ASTM D792).

[0115] POE3: A copolymer of ethylene and 1-octene, with an MFI of 1.0 dg / min (ASTM D1238 at 190°C with a 2.16 kg load) and 0.868 g / cm³. 3 The density (ASTM D792).

[0116] The components shown in Tables 1-3 are melt-mixed to obtain compositions having the properties measured as follows and shown in the table.

[0117] MFI (dg / min): ISO 1133 (2.16 kg, 230℃).

[0118] Impact strength of simply supported beam (kJ / m) 2 ISO 179, at 23°C, 0°C and -20°C.

[0119] Tensile modulus (MPa), yield tensile strength (MPa), tensile strength at break (MPa) and elongation at break (%): ISO 527.

[0120] Flexural modulus (MPa) and flexural strength (MPa): ISO 178.

[0121] Ash content: ISO 3451

[0122] Mold shrinkage (%), referred to as shrinkage in the context of this invention, is the amount of shrinkage experienced by the molded part when removed from the mold cavity and cooled at room temperature. Shrinkage was measured on 65×65×3.2 mm injection molded sheets after a 24-hour conditioning time following molding at room temperature (23°C) and 50% relative humidity, according to ISO 294-4. Each sample was molded under the same conditions on the molding machine. Shrinkage measured along the flow length and perpendicular to the flow is reported here. Shrinkage was determined using the following equation:

[0123]

[0124] Where L m L is the length of the mold in the direction under consideration. s This is the length of the sample in the direction under consideration. Contraction in the flow direction (labeled "contraction / / ") and contraction in the direction perpendicular to the flow direction (labeled "contraction L") are reported.

[0125] Gloss level: ASTM D2457, at 20° and 60°.

[0126] Stress-induced whitening:

[0127] Stress-induced whitening occurs when an object is subjected to stress after a whitening process, resulting in white areas. The appearance of these white areas indicates the onset of material failure. The whitening on the samples was achieved according to PV3905 by dropping a 500 (±5) g solid stainless steel ball (0 (50.0±0.03) mm) from a height of 230 mm onto a 100×100×2 mm specimen molded on an SE180 machine. These specimens were photographed using an EPSON V850 Pro scanner in professional mode. For scanning parameters, positive film was selected as film type, image type as b-bit grayscale, resolution as 800 dpi, and file size as 2.5×2.5 inches. Histogram adjustment was not performed during scanning.

[0128] Image analysis was performed on the MATLAB 2020a platform to determine the value of the parameter "spot size" (area).

[0129] The size (area) of the spot was determined as follows:

[0130] The overall whiteness of the entire image is calculated as the sum of the whiteness of each pixel in the image. The whiteness of the inherent material is defined as 0. Each pixel constituting the sample has a whiteness of 0-255. The spot size is defined as the size of the area that has 100% whiteness of the entire image.

[0131] Integral strength:

[0132] Regarding the integral intensity of the region ∑I×△x×△y, the intensity has been normalized by subtracting the median intensity of the environment.

[0133] The composition was injection molded into a suitcase with dimensions of 76 cm × 51 cm × 32 cm at 210°C according to QBT 2155-2010, and its properties were measured as follows and are shown in Tables 1-3.

[0134] Lifting test: QBT 2922-2007 (Luggage - Vibration and shock test method), is indicated as passed when no unacceptable damage is found after 2000 cycles.

[0135] Rolling test: QBT 4116-2010 (Luggage - Drum test method), indicated as pass when there is no unacceptable stress whitening.

[0136] Gloss: Visual inspection; if a high gloss is observed, it is considered passed.

[0137] Drop impact test: QBT 2921-2007 (Luggage - Drop test method), tested at -12°C for 6 hours. If no cracks are detected, it is considered a pass.

[0138] Drop test: QBT 2918-2007-T (Luggage - Method of testing for impact resistance by means of a drop hammer), if no crack is detected, it is indicated as pass.

[0139] Table 1

[0140] *The total rubber weight is the sum of the dispersed phase and POE in the ICP, expressed as a percentage by weight.

[0141] The composition of Ex 1 exhibits a good combination of impact strength, tensile properties, flexural properties, shrinkage, gloss and stress whitening properties, and suitcases made from the composition of Ex 1 have passed all relevant tests for suitcases.

[0142] The composition of CEx E cannot be injection molded into a suitcase of the specified dimensions at a temperature of 210°C. Therefore, it is understandable that the low MFI of the overall composition leads to injection molding difficulties. Furthermore, as can also be understood from CEx C and CEx D, it results in poor stress whitening properties.

[0143] From the comparison of Ex 1 with CEx A and CEx B, it can be understood that the use of the elastomer with high MFI according to the present invention results in better gloss and better stress whitening properties.

[0144] From the comparison of Ex 1 with CEx C and CEx D, it is understandable that using the homopolymer with high MFI according to the present invention results in better stress whitening properties.

[0145] Table 2

[0146] *The total rubber weight is the sum of the dispersed phase and POE in the ICP, expressed as a percentage by weight.

[0147] The compositions shown in Table 2, made using HDPE instead of propylene homopolymer, did not exhibit satisfactory stress-induced whitening properties. Gloss properties were also unsatisfactory.

[0148] From the comparison of CEx F, CEx G, CEx H and CEx I, it can be understood that when the total amount of rubber is too high, the tensile modulus and tensile strength become too low, and the luggage made from the composition fails the lifting and rolling tests and has a low gloss.

[0149] The difference in MFI between compositions CEx J and Ex 1 is small, but the composition of Ex 1 exhibits significantly better stress whitening and gloss properties. This can be attributed to the higher total rubber content in the composition of Ex 1.

[0150] Table 3

[0151] *The total rubber weight is the sum of the dispersed phase in ICP and PCR and POE, expressed as a percentage by weight.

[0152] The comparison between Ex1 and CEx K reveals that completely replacing ICP1 with PCR1 results in a significant decrease in impact strength and fails the lift-up test, drop ball impact test, and drop test—crucial for luggage applications. However, in Ex2 and Ex3, by combining ICP1 and PCR1 in an approximately 1:2 ratio, compositions with comparable physical properties to Ex1 and passing all key tests, and even exhibiting higher gloss performance, are obtained. Of course, environmental benefits are achieved in Ex2 and Ex3 through the use of a large amount of PCR material. As can be seen from CEx L and CEx M, not all types of PCR materials—despite having similar RC, RCC2, and MFI parameters—meet the requirements for luggage applications.

Claims

1. A composition comprising: (A1) a heterophasic propylene copolymer, (A2) a post-consumer recycled heterophasic propylene copolymer, (B) a propylene homopolymer, and (C) a polyolefin-based elastomer, wherein (A1) the heterophasic propylene copolymer has a melt flow index of 5.0 - 50 g / 10 min measured according to ISO 1133-1 :2011 at 230 °C with a load of 2.16 kg, and (A2) the post-consumer recycled heterophasic propylene copolymer has a melt flow index of 5.0 - 50 g / 10 min measured according to ISO 1133-1 :2011 at 230 °C with a load of 2.16 kg, an ash content of 0.5 wt% - 3.5 wt% measured according to ISO 3451 and a glossiness of 55 - 70 measured at 20° according to ASTM D2457.

2. The composition of claim 1, wherein, the weight ratio of (A2):(A1) is 1 - 3.

3. The composition according to any one of the preceding claims, wherein, relative to the total weight of the composition, the amount of (A1) is 20 - 30 wt%, preferably 23 - 27 wt%, the amount of (A2) is 40 - 65 wt%, preferably 50 - 55 wt%, the amount of (B) is 5 - 30 wt%, preferably 10 - 20 wt% and the amount of (C) is 1 - 15 wt%, preferably 5 - 10 wt%.

4. The composition according to any one of the preceding claims, wherein (A1) and (A2) respectively have a melt flow index of 10 - 40 g / 10 min, more preferably 20 - 35 g / 10 min, measured according to ISO 1133-1 :2011 at 230 °C with a load of 2.16 kg.

5. The composition according to any one of the preceding claims, wherein (A1) and (A2) respectively consist of (a1) a propylene-based matrix and (a2) dispersed ethylene-a-olefin copolymer, the amount of (a2) in (A1) and (A2) respectively is 2.0 - 40 wt%, such as at least 5.0 wt%, at least 10.0 wt%, or at least 15.0 wt%, and / or at most 35 wt%, at most 30 wt%, or at most 25 wt%.

6. The composition according to claim 5, wherein the total amount of (a2) and (C) relative to the total composition is 20 - 25 wt%.

7. The composition according to claim 5, wherein the amount of ethylene monomer units in (a2) the dispersed ethylene-a-olefin copolymer of the post-consumer recycled heterophasic propylene copolymer (A2) is 30 - 44 wt%, preferably 35 - 42 wt%.

8. The composition according to claim 1, wherein (A2) has a Charpy impact strength of 6.0-10.0 kJ / m 2 , preferably 6.5-8.0 kJ / m 2 , measured at 23 °C according to ISO 179.

9. The composition according to any one of the preceding claims, wherein (B) has a melt flow index of 25 - 100 dg / min, such as at least 30 dg / min, at least 40 dg / min, at least 45 dg / min or at least 50 dg / min, and / or such as at most 90 dg / min, at most 80 dg / min, at most 75 dg / min, at most 70 dg / min, measured according to ISO 1133-1 :2011 at 230 °C with a load of 2.16 kg.

10. The composition according to any one of the preceding claims, wherein (C) is a copolymer of ethylene and an alpha-olefin comonomer having 4-10 carbon atoms, preferably an ethylene-1-octene copolymer.

11. The composition according to any one of the preceding claims, wherein (C) has a melt flow index of 5-50 dg / min, preferably 10-45 dg / min, more preferably 15-40 dg / min, more preferably 25-35 dg / min, measured according to ASTM D1238 at a temperature of 190 °C with a load of 2.16 kg.

12. The composition according to any one of the preceding claims, wherein the composition has a melt flow index of 15-60 dg / min, preferably 20-50 dg / min, more preferably 25-40 dg / min, measured according to ISO 1133-1 :201 1 at a temperature of 230 °C with a load of 2.16 kg.

13. A process for the preparation of the composition according to any one of the preceding claims, comprising melt mixing (A1 ), (A2), (B), (C) and, optionally, (D) additives.

14. An article, preferably a luggage, obtained by injection molding the composition according to any one of claims 1 -12.

15. The article according to claim 14, which is a luggage having a capacity of 100-130 L, for example 105-120 L.

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