Polyolefin composition containing recycled propylene polymer

Abstract

The invention relates to polymer compositions containing recycled polyolefin material, which can be used for the manufacture of articles by injection moulding. The proposed polyolefin composition contains the following components, expressed on the basis of the total weight of the composition: A. a recycled propylene polymer in an amount of from 5 to 60 wt.%, B. a heterophase copolymer of propylene and ethylene in an amount of from 15 to 75 wt.%, C. a propylene homopolymer in an amount of from 20 to 25 wt.%, D. a nucleating additive in an amount of from 0.03 to 0.1 wt.%, E. an additive or mixture of additives other than a nucleating additive in an amount of from 0.05 to 0.5 wt.%, wherein the melt flow rate (MFR) values of components B and C satisfy the following ratios: 0.5 MFRA < MFRB < 1.5 MFRA and 0.4 MFRA < MFRC < 0.9 MFRA. The joint addition of a virgin heterophase copolymer of propylene and ethylene and a virgin propylene homopolymer with the given MFR levels to a recycled propylene polymer provides improved workability during injection moulding and lends the composition the level of impact-resistant and stress-strain properties necessary for articles for packaging various goods: an MFR (230°C / 2.16 kg) of from 20 to 40 g / 10 min, a flexural modulus of not less than 1400 MPa, and a notched Izod impact strength at 23°С of not less than 4.5 kJ / m2.

Description

[0001] POLYOLEFIN COMPOSITION CONTAINING RECYCLED POLYMER

[0002] Field of technology to which the invention relates

[0003] The present invention relates to polymer compositions that contain secondary polyolefin raw materials and can be used for the manufacture of articles by injection molding.

[0004] State of the art

[0005] Solving the global problem of environmental pollution with polymer waste is one of the most important aspects of sustainable development of the world economy. One of the main approaches to reducing the amount of polymers entering the environment is their secondary use, i.e. the involvement of polymer raw materials obtained from already used polymer products in a new production and consumption cycle.

[0006] In the case of polyolefins, after separation of polymers of a different nature (polyethylene terephthalate, polystyrene, polyamide, polyvinyl chloride and others), the secondary polyolefin raw material is, as a rule, a mixture of polypropylenes and polyethylenes, the composition of which varies over a wide range. To achieve satisfactory quality of products manufactured using secondary polyolefin raw materials, it is necessary to control the quality of the secondary raw material (its composition and purity), as well as to use special formulation solutions (introduction of additives, including compatibilizing ones, mixing with primary polymers), allowing to compensate for the low physical and mechanical properties of secondary polymers and the heterogeneity of the composition of secondary raw materials. The use of these approaches is widely disclosed in the state of the art devoted to the development of materials using secondary raw materials.

[0007] Thus, EP 1963067 [Basell Polyolefine, published 03.03.2010] discloses a composition including secondary raw materials obtained from polymer waste after the production of polymer products. The secondary raw materials used in this case are polyethylene, polypropylene or a mixture thereof, and the content of polar polymers in it, the presence of which may be caused by the presence of residues of barrier films in polymer waste, should not exceed 1.5 wt.%. In accordance with the invention disclosed in this publication, in order to achieve the required level of mechanical properties of the finished composition, the secondary raw materials are mixed with a specific heterophase polypropylene composition in an amount of 20 to 70 wt.%, characterized by a modulus of elasticity in bending of no more than 600 MPa and containing a copolymer of propylene with ethylene and ethylene-propylene rubber or ethylene-octene elastomer, as well as a special additive that allows for the compatibility of polar polymers with polyolefins, for example maleinized polypropylene.

[0008] WO 2021 / 071889 [Dow Global Technologies, published 15.04.2021] presents a composition suitable for three-dimensional printing (3D printing) by the fused deposition method, obtained by mixing secondary raw materials from 5 to 75 wt.% and a special block copolymer in an amount of 25 to 95 wt.% with an ethylene content of 60 to 70 mol.%, wherein the secondary raw materials used are a mixture of used polyolefins (LDPE, LLDPE, HDPE, PP, functionalized polyolefins) with a contaminant content (non-olefin polymers, inorganics, etc.) of no more than 1 wt.%.

[0009] In WO 2020 / 182435 [Basell Polyolefine, published 17.09.2020], it is proposed to use from 10 to 50 wt.% of a complex three-component mixture of primary polyolefins to improve the tensile properties of a polyolefin composition obtained using secondary raw materials in an amount of from 50 to 90 wt.%, containing from 50 to 90 wt.% of propylene units and from 5 to 40 wt.% of ethylene units, and optionally up to 15 wt.% of units of one or more olefins selected from 1-butene, 1-hexene and 1-octene. The proposed three-component blend of primary polyolefins contains from 5 to 35 wt.% of a propylene homopolymer or a propylene-ethylene copolymer with a propylene content of 90 wt.% or more, from 20 to 50 wt.% of an ethylene-alpha-olefin copolymer with an alpha-olefin content of up to 20 wt.%, and an elastomeric ethylene-propylene copolymer with an ethylene content of up to 75 wt.%. A similar approach is disclosed in WO 2020 / 182436 [Basell Polyolefine, published 17.09.2020] except that the mixture of primary polyolefins contains from 5 to 35 wt.% of a propylene homopolymer or a propylene-ethylene copolymer with a propylene content of 90 wt.%, from 20 to 50 wt.% of an ethylene homopolymer and from 30 to 60 wt.% of a terpolymer of ethylene, propylene and 1-butene.

[0010] In WO 2021 / 032460 [Borealis, published 25.02.2021], WO 2021 / 032459 [Borealis, published 25.02.2021], WO 2021 / 032458 [Borealis, published 25.02.2021] the secondary polyolefin feedstock is a mixture of polypropylene and polyethylene, and strict requirements are imposed on the content of a large list of foreign components. Thus, in particular, the content of polyamide, polystyrene, talc should be less than 5 wt.% for each component, chalk - less than 4 wt.%, paper, wood, metal - less than 1 wt.% for each component, limonene - less than 100 ppm, fatty acids - less than 200 ppm. These publications demonstrate the impact of using different types of primary polypropylene in compositions based on recycled materials of the same composition. In particular, adding 20 to 85 wt.% of a propylene homopolymer with certain characteristics to a mixture of secondary polyolefins makes it possible to improve the tensile modulus of the resulting composition (WO 2021 / 032460) compared to the same indicator for a composition obtained without adding a propylene homopolymer. While mixing a mixture of secondary polyolefins with a random propylene-ethylene copolymer with certain characteristics leads to an improvement in the tensile properties of the resulting composition (WO 2021 / 032459), and when mixing with a block copolymer with certain characteristics, a simultaneous improvement in the modulus of elasticity and impact strength of the resulting composition is observed (WO 2021 / 032458).

[0011] In the documents reviewed, as in many others related to this field of technology, polyolefin mixtures with a wide variability of composition are used as secondary polymer raw materials, which is associated with a wide range of used products used for recycling. This factor is one of the reasons why it is not possible to obtain products from them that can fully replace products obtained from primary polymers. Although a more detailed sorting of polymer waste, i.e. their separation during primary sorting by type of products and polymers (for example, polypropylene buckets and containers, polyethylene canisters, BOPP films, polyethylene stretch films, woven materials from polypropylene raffia, etc.) and, accordingly, the formation of batches of secondary raw materials with a narrower polymer composition, and would improve the quality of secondary raw materials and increase the stability of their characteristics, however, such a process of sorting secondary raw materials is extremely labor-intensive and energy-consuming and therefore leads to a significant increase in the cost of the final product.

[0012] The aim of the present invention is to develop a polyolefin composite material based on secondary raw materials that has satisfactory processability in the injection molding process and ensures the production of products with the necessary consumer qualities.

[0013] The essence of the invention

[0014] The present invention is based on the task of obtaining a composition based on a secondary propylene polymer, which would be characterized by an optimal combination of physical and mechanical properties and improved processability and would allow the possibility of its effective processing by injection molding into products whose properties would correspond to the requirements imposed on such products.

[0015] As used herein, the term "recycled propylene polymer" means post-consumer recycled propylene polymer, post-industrial recycled propylene polymer, and mixtures thereof.

[0016] As used in this description, the term "virgin propylene polymer" means a propylene polymer that is used for the first time and has not been subjected to a recycling procedure.

[0017] The technical result of the present invention consists in achieving improved processability of the proposed composition when using a secondary propylene polymer in it, expressed in ensuring a test article (3 l container) injection molding cycle time of up to 14 s, and in achieving the required level of physical and mechanical characteristics of both the composition itself, in particular a melt flow index (MFI) at 230 °C / 2.16 kg from 20 to 40 g / 10 min, a modulus of elasticity in bending of at least 1400 MPa and a notched Izod impact strength at 23 °C of at least 4.5 kJ / m3, and the test article, namely a 3 l container, such as its resistance to a vertical load of at least 2550 N and a maximum drop height (at 0 °C) of at least 0.8 m.

[0018] The specified technical problem is solved and the required technical result is achieved due to the fact that two primary propylene polymers are used in the composition based on the secondary polymer, namely: a heterophase copolymer of propylene with ethylene and a homopolymer of propylene with a certain MFR ratio. Thus, the polyolefin composition contains the following main components in terms of its total mass:

[0019] A. secondary propylene polymer in an amount of from 5 to 60 wt.%,

[0020] B. heterophasic copolymer of propylene with ethylene in an amount of 15 to 75 mass%,

[0021] B. propylene homopolymer in an amount of 20 to 25 wt.%,

[0022] G. nucleating additive (nucleating agent) in an amount of 0.03 to 0.1 wt.%,

[0023] D. an additive or a mixture of additives, different from the nucleating additive, in an amount from 0.05 to 0.5 wt.%, while the values ​​of the MFI of components B and C satisfy the following ratios:

[0024] 0.5PTR А < PTR Б < 1.5PTR А AND

[0025] 0.4PTR А < PTR В < 0.9PTR А .

[0026] The authors of the present invention unexpectedly found that only the combined introduction of primary heterophase propylene-ethylene copolymer and propylene homopolymer with certain MFI indices makes it possible to achieve the required level of impact-strength and deformation characteristics of the composition and the article obtained from it, while ensuring good processability of the composition when forming articles from it by injection molding (minimization of cycle time). Without relying on any specific theory, the authors of the present invention believe that the improvement of processability of the composition proposed in the invention can be due to the formation of a polymer mixture with an optimal molecular weight distribution of macromolecules.The very origin of secondary raw materials involves mixing polymers with different molecular weight characteristics, even despite careful primary selection of waste by polymer type, which inevitably leads to expansion of the molecular weight distribution of such mixtures. When introducing additional polymer components (primary polymers) to improve the physical and mechanical properties of the composition, there is a high probability of additional expansion of the molecular weight distribution, which can negatively affect the processability of the material. As is known, polymers with a narrow molecular weight distribution crystallize more easily and quickly than those with a wide one, namely, an increase in the crystallization rate ensures a reduction in the cycle time during the processing of propylene polymer by injection molding.In addition, from the point of view of polymer morphology, the expansion of the molecular weight distribution in the polymer leads to an increase in the defectiveness of the crystalline structure, which can reduce the impact strength characteristics.

[0027] The combination of two primary polymers, as well as the boundary conditions of the characteristics of the primary polymers, identified by the authors of the invention, make it possible to achieve the target physical and mechanical characteristics of the composition containing secondary raw materials without deteriorating its processability by injection molding.

[0028] Detailed description of the invention

[0029] The following is a detailed description of various aspects and embodiments of the present invention.

[0030] According to the present invention, its object is a composition containing the following main components, based on its total weight:

[0031] A. secondary propylene polymer in an amount of 5 to 60 wt.%,

[0032] B. a heterophasic copolymer of propylene with ethylene in an amount of 15 to 75 wt.%, C. a homopolymer of propylene in an amount of 20 to 25 wt.%,

[0033] G. nucleating additive in an amount of 0.03 to 0.1 wt.%,

[0034] D. an additive or a mixture of additives, different from the nucleating additive, in an amount from 0.05 to 0.5 wt.%, while the values ​​of the MFI of components B and C satisfy the following ratios:

[0035] 0.5PTR А < PTR Б < 1.5PTR А AND

[0036] 0.4PTR А < PTR В < 0.9PTR А .

[0037] The composition proposed in the invention satisfies the following physical and mechanical characteristics: MFI at 230°C / 2.16 kg from 20 to 40 g / 10 min, modulus of elasticity in bending of at least 1400 MPa, impact strength according to 2 Izod with a notch at 23°C of at least 4.5 kJ / m.

[0038] According to the present invention, a secondary propylene polymer is used as component A, which is regranulated consumer waste, mainly in the form of buckets, containers, etc. Such products are usually made from impact-resistant polypropylene, which has an elastomeric (rubber) fraction soluble in cold xylene. The secondary propylene polymer suitable for use in the composition proposed in the invention contains a heterophasic copolymer of propylene with ethylene in an amount of at least 90 wt.%, preferably 95 wt.%. The secondary propylene polymer may contain impurities of propylene homopolymer and / or ethylene homopolymer in an amount of no more than 5 wt.%. The secondary propylene polymer is characterized by a fraction content soluble in cold xylene of from 14 to 18 wt.%, preferably from 15 to 17 wt.%, MFR at 230°C / 2.16 kg from 25 to 55 g / 10 min, preferably from 35 to 55 g / 10 min, more preferably from 40 to 50 g / 10 min, and has a main maximum melting temperature in the range from 160 to 170°C.

[0039] In addition, an important aspect of the applicability of the secondary propylene polymer in the composition proposed in the invention is the degree of its contamination with foreign inclusions of a mineral or polymeric nature. As is known, foreign inclusions in the polymer are a source of defects in the supramolecular structure of polymers, capable of reducing the resistance of the material to impact loads. The melt contamination index of the secondary propylene polymer (FPV), determined using a filter tester, can be no more than 60 bar / kg, preferably no more than 30 bar / kg, more preferably no more than 10 bar / kg.

[0040] The amount of secondary propylene polymer (component A) in the composition can be from 5 to 60 mass%, preferably from 10 to 50 mass%, more preferably from 20 to 40 mass%, based on the total weight of the composition.

[0041] In order to ensure the required level of physical and mechanical properties and processability of the composition during the injection molding process, primary propylene polymers were introduced into its composition containing a secondary propylene polymer, namely: a heterophase copolymer of propylene with ethylene (component B) and a homopolymer of propylene (component C), with certain MFIs.

[0042] As component B, a heterophasic copolymer of propylene with ethylene is used, characterized by an ethylene content of 7 to 9 wt.%, preferably 7.5 to 8.5 wt.%, and a xylene-soluble fraction of 12 to 19 wt.%, preferably 14 to 18 wt.%, and a MFI value satisfying the following ratio: 0.5 MFId < MFIB < 1.5 MFId. In one embodiment of the invention, a mixture of heterophasic copolymers of propylene with ethylene that satisfy the specified requirements can be used. Examples of heterophasic copolymers of propylene with ethylene are any industrial heterophasic copolymers that satisfy the above requirements, in particular the products known under the trade marks SIBEX PP I452IM, PP8440R manufactured by PJSC Sibur Holding.

[0043] The amount of heterophasic copolymer of propylene with ethylene (component B) in the composition can be from 15 to 75 mass% based on the total mass of the composition.

[0044] Any industrial propylene homopolymer with a MFI value satisfying the following ratio is used as component B: 0.4 MFId < MFIc < 0.9 MFId. In one embodiment of the invention, a mixture of propylene homopolymers satisfying the specified requirement can be used. Examples of commercially available propylene homopolymers include, but are not limited to, products known under the trade names SIBEX PP H250GP, SIBEX PP H253 FF, SIBEX PP H270 FF manufactured by PJSC Sibur Holding.

[0045] The amount of propylene homopolymer (component B) in the composition can be from 20 to 25 mass% based on the total weight of the composition.

[0046] The composition proposed in the invention also contains at least one nucleating additive (nucleating agent) (component G), which can be any nucleating additives known from the prior art, primarily alpha-nucleators of propylene polymers. As an example of such nucleators, one can name products known on the market under the trade names ADK STAB NA-71, ADK STAB NA-11, ADK STAB NA-27, Hyperform HPN20E and the like.

[0047] The content of the nucleating additive (component G) in the composition is from 0.03 to 0.10 wt.%, preferably from 0.05 to 0.07 wt.%, based on the total weight of the composition.

[0048] The composition may also contain, based on its total weight, from 0.05 to 0.5 wt.% of various additives (component D), namely: antioxidant stabilizers, heat stabilizers, light stabilizers or mixtures thereof, and / or other additives, such as pigments, lubricants, processing (technological) additives, and others. Examples of stabilizers are tetrakis-[methylene-3-(3, 5-di-t / ?et-butyl-4-hydroxyphenyl)propionate]methane, known under the trade name Irganox 1010, tri-(phenyl-2,4-di-t / ?et-butyl)phosphite, known under the trade name Irgafos 168, and / or similar stabilizers of other trade names, as well as light stabilizers of the type of sterically hindered amines, known under the trade names Tinuvin 622, Himasorb 944 and others, and mixed systems of stabilizers under such trade names as Irganox B225, Irganox B215 and others.

[0049] The intended purpose of the composition proposed in the invention is to manufacture products for packaging various goods by injection molding. Specific examples of such products include, but are not limited to, containers and buckets. To ensure the safety of goods, certain requirements are imposed on the packaging for resistance to deformation and impact. The composition proposed in the invention provides the necessary balance of these characteristics: for a test product (a 3-liter container measuring 200x100x100 mm), the resistance to vertical load is at least 2550 N, the maximum drop height at 0°C is at least 0.8 m (according to GOST 33756, p. 5, table 3, strength category 1). At the same time, the composition proposed in the invention has good manufacturability in the manufacture of products by injection molding, which is manifested in the fact that the cycle time for manufacturing a test product (a 3-liter container) is no more than 14 s.

[0050] Implementation of the invention

[0051] Test methods

[0052] The determination of the MFI at a temperature of 230°C and a load of 2.16 kg (230°C / 2.16 kg) was carried out in accordance with the ISO 1133 standard.

[0053] The Izod notched impact strength at 23°C was determined in accordance with ISO 180.

[0054] The determination of the flexural modulus was carried out in accordance with ISO 178.

[0055] The determination of the properties of the finished product (a 3-liter container), which are resistance to vertical load and maximum drop height at 0°C, was carried out in accordance with the GOST 33756 standard.

[0056] The mass fraction of cold n-xylene-soluble substances in secondary propylene polymer (XS) was determined in accordance with ISO 16152 (E) "Polymers. Determination of xylene-soluble substances in polypropylene".

[0057] Determination of melting and crystallization temperatures was carried out by differential scanning calorimetry in an inert atmosphere at a heating / cooling rate of 10°C / min in accordance with ISO 11357-3 "Plastics. Differential scanning calorimetry. Part 3. Determination of melting and crystallization temperature and enthalpy".

[0058] The contamination index (filtration pressure value FPV) was determined using a Brabender Filtrates! filter tester connected to a Brabender E25 single-screw extruder. The test involves passing a certain amount of polymer through a filter while simultaneously measuring the pressure build-up. The fine mesh of the filter blocks large particles without letting them through. As the degree of blocking of the filter by large particles increases, the polymer flow becomes more restricted, which leads to an increase in the melt pressure directly in front of the filter. The filter test yields a pressure change curve over time and the FPV value, also called the contamination index. The following extrusion conditions were used for secondary propylene polymer: extruder barrel temperature 240°C, sample weight 2000 g, filter mesh pore diameter 125 μm.

[0059] The test product, namely a 3-liter container measuring 200x100x100 mm, was manufactured using injection molding on a Sumitomo SHIDEMAG El-Exis SP 150 / 500-675 injection molding machine at a material cylinder temperature of 240°C, a maximum injection speed of 150 mm / s, and a maximum injection pressure of 75±2 bar.

[0060] Materials used in examples

[0061] The recycled, used propylene polymer used was regranulate (rPP), the source of which was used buckets. The characteristics of the used secondary propylene polymers were as follows:

[0062] - rPSh: MFR (230°C / 2.16 kg) 40.4 g / 10 min, melting point 166.4°C, crystallization temperature 125.9°C, XS 15.8 wt.%, FPV 8 bar / kg;

[0063] - rPP2: MFR (230°C / 2.16 kg) 44 g / 10 min, melting point 165.4°C, crystallization temperature 125.3°C; XS 15.5 wt.%, FPV 54 bar / kg;

[0064] - rPPZ: MFR (230°C / 2.16 kg) 49.7 g / 10 min, melting point 164.9°C, crystallization temperature 126.1 °C, XS 15.4 wt.%, FPV 390 bar / kg;

[0065] - rPP4: MFR (230°C / 2.16 kg) 36.9 g / 10 min, melting point 165.9°C, crystallization temperature 125.1°C, XS 15.5 wt.%, FPV 2.2 bar / kg.

[0066] It should be noted that the crystallization temperature of propylene polymers above 120°C indicates the presence of nucleating additives in the polymer.

[0067] As a primary heterophase copolymer of propylene with ethylene, products of the PP I452IM, PP 8440R, PP 8400N brands manufactured by PJSC Sibur Holding with the following characteristics were used:

[0068] - PP I452IM MFR (230°C / 2.16 kg) 45 g / 10 min, XS 18.5 wt.%, ethylene content 7.7 wt.%; - PP8440R: MFR (230°C / 2.16 kg) 30 g / 10 min, XS 14.7 wt.%, ethylene content 7.0 wt.%,

[0069] - PP 8400N: MFR (230°C / 2.16 kg) 12.5 g / 10 min, XS 14.8 wt.%, ethylene content 8.1 wt.%.

[0070] As a propylene homopolymer, products of the PP H120GP and PP H250GP brands manufactured by PJSC Sibur Holding were used with the following characteristics:

[0071] - PP H120GP PTR (230°C / 2.16 kg) 12 g / 10 min;

[0072] - PP H250GP PTR (230°C / 2.16 kg) 25 g / 10 min.

[0073] The following polymer additives were used: stabilizers Irganox 1010, Irgafos 168, nucleating additives ADEKA NA-71, Hyperform HPN20E, antacid DHT 4A.

[0074] Example 1 (according to the invention)

[0075] A preliminary mixture of granules of primary polymers PPH250GP and PPI452IM with additives (stabilizers, nucleating additive, antacid) was prepared in a paddle mixer according to the composition recipe given in Table 1. The polymer components were mixed with additives for a period of 2 to 10 minutes at room temperature. Then the resulting mixture was fed by a dispenser into the loading zone of a twin-screw extruder Coperion ZSK26 Мс18, and the regranulate rPP1 was fed into it by another dispenser. Compounding was carried out using a filter mesh with a hole size of 350 μm at a maximum temperature in the cylinder zones of 210°C and a screw speed of 400 min \

[0076] The resulting granulated compound was then used to determine the MFI values ​​(230°C / 2.16 kg), to manufacture standard samples for physical and mechanical testing by injection molding, and to manufacture test articles, namely 3-liter containers (200x100x100 mm in size).

[0077] The production of standard samples for physical and mechanical testing was carried out on a Sumitomo SHIDEMAG Systec 50 / 370-200 injection molding machine.

[0078] The test articles (3 l container) were manufactured on a Sumitomo SHIDEMAG El-Exis SP 150 / 500-675 injection molding machine at a cylinder temperature of 240°C and a maximum injection speed of 150 mm / s. The test results for the composition obtained in Example 1 and the container manufactured from it are shown in Table 1.

[0079] Example 2 (according to the invention)

[0080] In this example, the work was similar to example 1, except that the secondary propylene polymer used was regranulate rPP4.

[0081] The test results of the composition obtained in Example 2 and the container made from it are shown in Table 1.

[0082] Example 3 (according to the invention)

[0083] In this example, the work was similar to example 1, except that the secondary propylene polymer used was regranulate rPP2.

[0084] The test results of the composition obtained in Example 3 and the container made from it are shown in Table 1.

[0085] Example 4 (comparative)

[0086] In this example, the work was similar to example 1, except that the secondary propylene polymer used was regranulate rPP2, and the composition did not contain a nucleating additive.

[0087] The test results of the composition obtained in Example 4 and the container made from it are shown in Table 1.

[0088] Example 5 (according to the invention)

[0089] In this example, the procedure was similar to example 1, except that the secondary propylene polymer used was PP2 regranulate, and its content was 20 wt%.

[0090] The test results of the composition obtained in Example 5 and the container made from it are shown in Table 1.

[0091] Example b (according to the invention)

[0092] In this example, the procedure was similar to example 1, except that the secondary propylene polymer used was PP2 regranulate, and its content was 40 wt%.

[0093] The results of testing the composition obtained in Example 6 and the container made from it are given in Table 1. Example 7 (according to the invention)

[0094] In this example, the procedure was similar to example 1, except that the secondary propylene polymer used was PP2 regranulate, and its content was 60 wt.%.

[0095] The test results of the composition obtained in Example 7 and the container made from it are shown in Table 1.

[0096] Example 8 (comparative)

[0097] In this example, the procedure was similar to example 1, except that the secondary propylene polymer used was PP2 regranulate, and its content was 75 wt.%.

[0098] The test results of the composition obtained in Example 8 and the container made from it are shown in Table 1.

[0099] Example 9 (comparative)

[0100] In this example, the work was similar to example 1, except that the secondary propylene polymer used was regranulate rPP2, and the composition did not contain primary propylene homopolymer or nucleating additive.

[0101] The test results of the composition obtained in Example 9 and the container made from it are shown in Table 1.

[0102] Example 10 (comparative)

[0103] In this example, the process was similar to example 1, except that the composition did not contain primary propylene homopolymer or nucleating additive.

[0104] The test results of the composition obtained in Example 10 and the container made from it are shown in Table 1.

[0105] Example 11 (comparative)

[0106] In this example, the work was similar to example 1, except that the secondary propylene polymer used was regranulate rPP2, and the composition did not contain primary propylene homopolymer.

[0107] The results of testing the composition obtained in Example 11 and the container made from it are given in Table 1. Example 12 (comparative)

[0108] In this example, the work was similar to example 1, except that the PP2 regranulate was used as the secondary propylene polymer, the PP8440R copolymer was used as the heterophase copolymer of propylene with ethylene, and the composition did not contain primary propylene homopolymer.

[0109] The test results of the composition obtained in Example 12 and the container made from it are shown in Table 1.

[0110] Example 13 (comparative)

[0111] In this example, the process was similar to example 1, except that the PP8440R copolymer was used as the heterophase copolymer of propylene with ethylene, and the composition did not contain primary propylene homopolymer.

[0112] The test results of the composition obtained in Example 13 and the container made from it are shown in Table 1.

[0113] Example 14 (comparative)

[0114] In this example, the work was similar to example 1, except that the PP2 regranulate was used as the secondary propylene polymer, the PP8440R copolymer was used as the heterophase copolymer of propylene with ethylene, and the composition did not contain the primary propylene homopolymer or the nucleating additive.

[0115] The test results of the composition obtained in Example 14 and the container made from it are shown in Table 1.

[0116] Example 15 (comparative)

[0117] In this example, the procedure was similar to example 1, except that the secondary propylene polymer used was regranulate rPP2, and the content of primary propylene homopolymer in the composition was 15 wt.%.

[0118] The test results of the composition obtained in Example 15 and the container made from it are shown in Table 1.

[0119] Example 16 (comparative)

[0120] In this example, the work was similar to example 1, except that the secondary propylene polymer was regranulate RPP2, and the composition did not contain primary propylene homopolymer, instead of which a heterophase copolymer of propylene with ethylene of the PP 8400N grade was added in an amount of 15 wt%.

[0121] The test results of the composition obtained in Example 16 and the container made from it are shown in Table 1.

[0122] Example 17 (comparative)

[0123] In this example, the work was similar to example 1, except that the secondary propylene polymer was regranulate rPP2, and the primary propylene homopolymer was propylene homopolymer grade PP H120GP.

[0124] The test results of the composition obtained in Example 17 and the container made from it are shown in Table 1.

[0125] Example 18

[0126] In this example, the procedure was similar to example 1, except that the secondary propylene polymer used was regranulate rPP4, and a different nucleating additive was used in the composition.

[0127] The test results of the composition obtained in Example 18 and the container made from it are shown in Table 1.

[0128] Example 19 (comparative)

[0129] In this example, the work was similar to example 1, except that the secondary propylene polymer was PPZ regranulate. When compounding the composition using this secondary polymer, a rapid increase in melt pressure in the extruder and an excess of the permissible load on the motor were noted, which did not allow the necessary amount of material to be produced for testing.

[0130] Table 1: Composition and properties of the compositions from the examples

[0131]

[0132] Note: the content of each component is indicated in mass%.

[0133] 0

[0134] The compositions proposed in the invention (examples 1, 2, 3, 5, 6, 7, 18) demonstrate the possibility of obtaining a polyolefin composition of the claimed composition, while observing the fulfillment of the specified inequalities, with a recycled material content of up to 60 wt.%, possessing good processability and ensuring the manufacture of articles with the required level of properties. Characteristics of the polyolefin composition proposed in the invention: flexural modulus of more than 1400 MPa, 2 Izod impact strength of more than 4.5 kJ / m, article injection molding cycle time (3 l container) of 12-14 s. Properties of the test article (3 l container): resistance to vertical load of at least 2550 N, maximum drop height at 0°C of at least 0.8 m.The indicator "maximum drop height at 0°C" shows the greatest sensitivity to the degree of contamination of secondary raw materials: compositions of the same composition (examples 1, 2, 3), differing in the quality of the secondary polymer used with contamination indices of 8, 54, 2.2 bar / kg, respectively, clearly differ in the values ​​of the maximum drop height at 0°C: 1.4, 0.8, 1.7 m, respectively.

[0135] It should be noted that the compositions proposed in the invention are presented in a range of secondary propylene polymer content from 20 to 60 mass%. The authors of the present invention believe that it is impractical to provide examples with a secondary propylene polymer content from 5 to 20 mass%, since it is obvious to expect that a decrease in the secondary propylene polymer content in the composition will improve the physicomechanical properties and processability.

[0136] The composition from example 4 (comparative example) demonstrates reduced characteristics with the formulation not containing a nucleating additive: a modulus of elasticity in bending of less than 1400 MPa, and a decrease in resistance to vertical load of the test article (a 3-liter container), which is less than 2550 N.

[0137] The polyolefin composition from example 8 (comparative example) demonstrates a decrease in its characteristics with a secondary raw material content of more than 60 wt.%: flexural modulus less than 1400 MPa, Izod impact strength 4.8 kJ / m3, and a decrease in the properties of the test article (3 l container): resistance to vertical load less than 2550 N, maximum drop height at 0°C less than 0.8 m.

[0138] The polyolefin compositions from examples 9, 10, 11, 12, 13, 14 (comparative examples) demonstrate an unsatisfactory level of their characteristics in the absence of primary propylene homopolymer in their composition, regardless of the presence of a nucleating additive: a modulus of elasticity in bending of less than 1400 MPa and reduced resistance to vertical load of the test article (a 3-liter container), amounting to less than 2550 N.

[0139] Moreover, the compositions from examples 9 and 12, which differ from the compositions from examples 10 and 13, respectively, only in the quality of the secondary raw material (higher FPV value), demonstrate a reduced value of the “maximum drop height” indicator at 0°C.

[0140] The polyolefin composition from example 15 (comparative example) demonstrates an unsatisfactory level of its characteristics when the content of primary propylene homopolymer in its composition is less than 20 wt.%: a modulus of elasticity in bending of less than 1400 MPa and reduced resistance to vertical load of the test article (a container with a volume of 3 l), amounting to less than 2550 N.

[0141] The polyolefin composition from Example 16 (comparative example) demonstrates a deterioration in its processability when using a second heterophasic copolymer of propylene with ethylene instead of a propylene homopolymer: an unacceptable increase in the injection molding cycle time by more than 1.5 times.

[0142] The polyolefin composition from example 17 (comparative example) demonstrates a deterioration in its processability when using in its composition a primary propylene homopolymer with a MFI value of less than 0.4 MFId: an unacceptable increase in the injection molding cycle time by more than 1.5 times.

[0143] Example 19 (comparative example) demonstrates the impossibility of preparing a composition using raw materials with a high contamination index due to rapid contamination of the filter mesh and, accordingly, rapid growth of material pressure in the extruder and exceeding the permissible loads on the engine.

Claims

CLAUSES OF THE INVENTION 1. A polyolefin composition for the manufacture of products by injection molding, containing the following components based on its total weight: A. secondary propylene polymer in an amount of 5 to 60 wt.%, B. heterophasic copolymer of propylene with ethylene in an amount of 15 to 75% by weight, B. propylene homopolymer in an amount of 20 to 25 wt.%, G. nucleating additive in an amount of 0.03 to 0.1 wt.%, D. an additive or a mixture of additives, other than the nucleating additive, in an amount of 0.05 to 0.5 wt.%, wherein the melt flow index (MFI) values ​​of components B and C satisfy the following ratios: 0.5PTR А < PTR Б < 1.5 PTR А AND 0.4PTR А < PTRv < 0.9 PTR А , and satisfying the following characteristics: ITR at 230°C / 2, 16 kg from 20 to 40 g / 10 min, flexural modulus of at least 1400 MPa, impact 2 Izod viscosity with notch at 23 °C not less than 4.5 kJ / m3.

2. A polyolefin composition according to claim 1, characterized in that the content of component A, based on its total weight, is from 10 to 50% by weight, preferably from 20 to 40% by weight.

3. A polyolefin composition according to claim 1, characterized in that the content of component G, based on its total weight, is from 0.05 to 0.07 wt.%.

4. A polyolefin composition according to claim 1, characterized in that component A contains a heterophasic copolymer of propylene with ethylene in an amount of at least 90% by weight, preferably 95% by weight.

5. A polyolefin composition according to claim 1, characterized in that component A contains a fraction soluble in cold xylene in an amount of 14 to 18 wt.%, preferably 15 to 17 wt.%.

6. A polyolefin composition according to claim 1, characterized in that component A has a MFI at 230°C / 2.16 kg of 25 to 55 g / 10 min, preferably 35 to 55 g / 10 min, preferably 40 to 50 g / 10 min.

7. A polyolefin composition according to claim 1, characterized in that component A has a main maximum melting temperature in the range from 160 to 170°C.

8. A polyolefin composition according to claim 1, characterized in that component A has a contamination index of no more than 60 bar / kg, preferably no more than 30 bar / kg, more preferably no more than 10 bar / kg.

9. A polyolefin composition according to claim 1, characterized in that component B is characterized by an ethylene content of 7 to 9 wt.%, preferably 7.5 to 8.5 wt.%.

10. A polyolefin composition according to claim 1 or 9, characterized in that component B is characterized by a content of a fraction soluble in xylene of 12 to 19 wt.%, preferably 14 to 18 wt.%.

11. An article made from a composition according to any of paragraphs 1-10, manufactured by injection molding.

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