Propylene-based impact polymers and their preparation and use

Abstract

The present invention relates to an impact copolymer based on propylene, which comprises (A) polypropylene and (B) an ethylene-propylene copolymer. Based on the total weight of the propylene-based impact copolymer, the content of the ethylene-propylene copolymer is greater than or equal to 20% by weight. The propylene-based impact copolymer has a melt flow rate (230 °C / 2.16 kg) of 8 g / 10 min to 20 g / 10 min. The polypropylene has a melt flow rate (230 °C / 2.16 kg) of 35 g / 10 min to 55 g / 10 min. The molar ratio of the copolymer portion with the content of ethylene-derived units in the range of 45-55 mol% to the copolymer portion with the content of ethylene-derived units in the range of 20-30 mol% in the ethylene-propylene copolymer is 1.2 or more. The present invention also relates to the use of the impact copolymer. The impact copolymer not only has an improved rigidity-toughness balance at room temperature but also has improved low-temperature impact resistance performance and can be applied to a variety of applications.

Description

Technical Field

[0001] The present invention relates to polypropylene-based polymers. More specifically, the present invention relates to an impact copolymer based on propylene, and its preparation and uses. Background Art

[0002] An impact copolymer based on propylene (ICP) is a multiphase polymer blend in which polypropylene (PP) is the matrix (continuous phase) and an ethylene-propylene copolymer (EPR) is the dispersed phase (rubber phase), and the rubber phase functions as a toughening agent therein. ICP materials are widely used in various fields of industry and social life, including fields such as automotive, household appliances, and rigid packaging. These different application fields have different performance requirements for ICP materials. For example, it is required that ICP materials can be applicable to a wide temperature range from high temperature to low temperature. Generally, one grade / specification of ICP cannot cover all application fields, which results in increased costs for customers and raw material suppliers when using or producing them respectively. In addition, as lightweight becomes a development trend in various fields, the requirement for material toughness is also getting higher and higher. This poses further challenges to the development of polypropylene impact copolymers.

[0003] Therefore, there is a need to provide an impact copolymer based on propylene, which can achieve performance improvement at room temperature and low temperature, not only has an improved rigidity-toughness balance at room temperature, but also has improved low-temperature impact resistance performance, meeting the performance requirements of the impact copolymer based on propylene at room temperature and low temperature. Summary of the Invention

[0004] In order to solve the problems in the prior art, the present invention provides an impact copolymer based on propylene. The impact copolymer based on propylene of the present invention achieves satisfactory performance, especially not only has an improved rigidity-toughness balance at room temperature, but also has improved low-temperature impact resistance performance, which enables it to be applicable to a variety of applications.

[0005] The main aspect of the present invention relates to an impact copolymer based on propylene, which comprises or consists of the following:

[0006] (A) Polypropylene; and

[0007] (B) An ethylene-propylene copolymer,

[0008] wherein:

[0009] Based on the total weight of the impact copolymer based on propylene, the content of the ethylene-propylene copolymer is greater than or equal to 20% by weight,

[0010] The impact copolymer based on propylene has a melt flow rate (230°C / 2.16 kg) of 8 g / 10 min to 20 g / 10 min,

[0011] The polypropylene has a melt flow rate (230 °C / 2.16 kg) of 35 g / 10 min to 55 g / 10 min, and

[0012] in the ethylene-propylene copolymer, the molar ratio of the copolymer portion having an ethylene-derived unit content in the range of 45 - 55 mol% to the copolymer portion having an ethylene-derived unit content in the range of 20 - 30 mol% is 1.2 or more.

[0013] The present invention also relates to a method for preparing the propylene-based impact copolymer, the use of the propylene-based impact copolymer, and an article obtained from the propylene-based impact copolymer.

[0014] The propylene-based impact copolymer of the present invention achieves satisfactory performance characteristics, such as a satisfactory glass transition temperature (Tg) of the rubber phase, and in particular, achieves impact resistance in a wide temperature range, maintaining high impact resistance at room temperature and low temperatures (such as -20 °C). Moreover, the propylene-based impact copolymer of the present invention maximizes the toughening efficiency of the rubber and improves the stiffness-toughness balance at room temperature. These advantages of the present invention make it possible to be applicable to more applications. Detailed Description

[0015] The present invention is further described in detail below by way of specific embodiments. These specific embodiments are given for illustrative purposes only and do not limit the scope of protection of the present invention. The scope of protection required by the present invention is defined by the claims.

[0016] As used herein, the concept of "polymer" encompasses homopolymers and copolymers, where "copolymer" refers to a polymer formed by the polymerization of two or more monomers.

[0017] As used herein, a multiphase blend refers to a composition having two or more morphological phases in the same state. For example, a blend of two polymers in which one polymer forms discrete small packets (fine dispersion regions) dispersed in the matrix of the other polymer can be said to be multiphase in the solid state. The so-called continuous phase refers to the matrix phase in the multiphase blend, and the so-called discontinuous phase refers to the dispersed phase in the multiphase blend.

[0018] Propylene-based impact copolymer

[0019] A first aspect of the present invention relates to a propylene-based impact copolymer comprising or consisting of the following:

[0020] (A) Polypropylene; and

[0021] (B) An ethylene-propylene copolymer,

[0022] wherein:

[0023] Based on the total weight of the propylene-based impact copolymer, the content of the ethylene-propylene copolymer is greater than or equal to 20% by weight, preferably greater than or equal to 23% by weight, more preferably in the range of 23 to 35% by weight.

[0024] The propylene-based impact copolymer has a melt flow rate (230 °C / 2.16 kg) of 8 g / 10 min to 20 g / 10 min, preferably 10 g / 10 min to 15 g / 10 min.

[0025] The polypropylene has a melt flow rate (230 °C / 2.16 kg) of 35 g / 10 min to 55 g / 10 min, preferably 38 g / 10 min to 48 g / 10 min, and

[0026] In the ethylene-propylene copolymer, the molar ratio of the copolymer portion with the ethylene-derived unit content in the range of 45 - 55 mol% to the copolymer portion with the ethylene-derived unit content in the range of 20 - 30 mol% is 1.2 or more.

[0027] Component A

[0028] The propylene-based impact copolymer of the present invention comprises polypropylene as component A. The polypropylene described herein is a propylene homopolymer. The homopolymer can be atactic polypropylene, isotactic polypropylene, syndiotactic polypropylene, and blends thereof. The so-called "propylene homopolymer" means that, based on the weight of the polymer, the polymer contains 0.01 or 0.1 or 0.5 to 2.0 or 3.0 wt% of ethylene or C4-C 10 α-olefin-derived units, and the remainder are propylene-derived units, and most preferably refers to a polymer composed of propylene-derived units. In this text, an olefin with a double bond at the end position is called an α-olefin.

[0029] In some embodiments, the polypropylene described herein can have a weight average molecular weight Mw of, for example, 30,000 to 500,000 g / mol, such as 30,000 g / mol, 50,000 g / mol, 100,000 g / mol, 150,000 g / mol, 180,000 g / mol, 200,000 g / mol, 240,000 g / mol, 280,000 g / mol, 300,000 g / mol, 350,000 g / mol, 400,000 g / mol, 450,000 g / mol, 500,000 g / mol, and any weight average molecular weight Mw between any of these values.

[0030] In some embodiments, the polypropylene described herein can have a polydispersity index Mw / Mn of, for example, 1 to 20, such as 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, and a polydispersity index Mw / Mn between any of these values, preferably having a polydispersity index Mw / Mn in the range of, for example, 1 to 10, such as 1 to 5.

[0031] As component A, the melt flow rate (MFR) (ASTM D1238, 230 °C, 2.16 kg) of the polypropylene described herein is in the range of 35 g / 10 min to 55 g / 10 min. For example, as component A, the melt flow rate (MFR) (ASTM D1238, 230 °C, 2.16 kg) of the polypropylene described herein can be 35 g / 10 min, 38 g / 10 min, 40 g / 10 min, 42 g / 10 min, 45 g / 10 min, 47 g / 10 min, 50 g / 10 min, 52 g / 10 min, 55 g / 10 min, and values between any of these values. Preferably, as component A, the melt flow rate (MFR) (ASTM D1238, 230 °C, 2.16 kg) of the polypropylene described herein is in the range of 38 g / 10 min to 48 g / 10 min.

[0032] In the propylene-based impact copolymer of the present invention, preferably, based on the total weight of the propylene-based impact copolymer, the content of the polypropylene is in the range of 60 to 80% by weight, such as its content is 60% by weight, 65% by weight, 70% by weight, 75% by weight, 80% by weight, or any value between these values, preferably in the range of 65 to 80% by weight, more preferably in the range of 65 to 77% by weight, such as in the range of 70 to 77% by weight.

[0033] Component B

[0034] The propylene-based impact copolymer of the present invention comprises an ethylene-propylene copolymer as component B. In the present invention, the ethylene-propylene copolymer refers to a polymer obtained by copolymerizing ethylene and propylene.

[0035] In the ethylene-propylene copolymer suitable as Component B of the present invention, the molar ratio of the copolymer portion with the content of ethylene-derived units in the range of 45-55 mol% to the copolymer portion with the content of ethylene-derived units in the range of 20-30 mol% is 1.2 or more. For example, the molar ratio of the copolymer portion with the content of ethylene-derived units in the range of 45-55 mol% to the copolymer portion with the content of ethylene-derived units in the range of 20-30 mol% is 1.2 or more, 1.3 or more, 1.4 or more, 1.5 or more, 1.6 or more, 1.7 or more, 1.8 or more, 1.9 or more, 2 or more, 2.2 or more, 2.4 or more, 2.5 or more, 2.8 or more, 3 or more, 3.5 or more, 4 or more, 4.5 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, 15 or more, or a number between any of these values. Preferably, in the ethylene-propylene copolymer suitable as Component B of the present invention, the molar ratio of the copolymer portion with the content of ethylene-derived units in the range of 45-55 mol% to the copolymer portion with the content of ethylene-derived units in the range of 20-30 mol% is from 1.2 to 10, preferably from 1.2 to 5, more preferably from 1.2 to 3, such as from 1.5 to 2.5.

[0036] In some embodiments, the ethylene-propylene copolymer may have a weight-average molecular weight (Mw) in the range of 250,000 to 700,000 g / mol. For example, the weight-average molecular weight of the ethylene-propylene copolymer can be 250,000 g / mol, 280,000 g / mol, 300,000 g / mol, 320,000 g / mol, 350,000 g / mol, 380,000 g / mol, 400,000 g / mol, 420,000 g / mol, 450,000 g / mol, 480,000 g / mol, 500,000 g / mol, 520,000 g / mol, 550,000 g / mol, 580,000 g / mol, 600,000 g / mol, 620,000 g / mol, 650,000 g / mol, 680,000 g / mol, or 700,000 g / mol, or can be any value between these values.

[0037] In some embodiments, the ethylene-propylene copolymer may have a molecular weight distribution (Mw / Mn) of 3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 7.0, 8.0, 9.0 or a value between any of these values.

[0038] In the propylene-based impact copolymer of the present invention, based on the total weight of the propylene-based impact copolymer, the content of the ethylene-propylene copolymer is greater than or equal to 20% by weight, for example, greater than or equal to 23% by weight. For example, based on the total weight of the propylene-based impact copolymer, the content of the ethylene-propylene copolymer can be 20% by weight, 22% by weight, 23% by weight, 24% by weight, 26% by weight, 28% by weight, 30% by weight, 35% by weight, 40% by weight, or any content between these values. Preferably, the content of the ethylene-propylene copolymer is in the range of 23 to 35% by weight, for example, in the range of 23 to 30% by weight.

[0039] Impact copolymer

[0040] The impact copolymer of the present invention is a propylene-based impact copolymer.

[0041] In some embodiments, the present invention relates to a propylene-based impact copolymer comprising or consisting of the following:

[0042] (A) Polypropylene, preferably propylene homopolymer; and

[0043] (B) Ethylene-propylene copolymer,

[0044] Wherein:

[0045] Based on the total weight of the propylene-based impact copolymer, the content of the ethylene-propylene copolymer is greater than or equal to 20% by weight,

[0046] The propylene-based impact copolymer has a melt flow rate (230 °C / 2.16 kg) of 8 g / 10 min to 20 g / 10 min,

[0047] The polypropylene has a melt flow rate (230 °C / 2.16 kg) of 35 g / 10 min to 55 g / 10 min, and

[0048] In the ethylene-propylene copolymer, the molar ratio of the copolymer portion with the content of ethylene-derived units in the range of 45 - 55 mol% to the copolymer portion with the content of ethylene-derived units in the range of 20 - 30 mol% is 1.2 or more.

[0049] In some embodiments, the present invention relates to a propylene-based impact copolymer comprising or consisting of the following:

[0050] (A) Polypropylene, preferably propylene homopolymer; and

[0051] (B) Ethylene-propylene copolymer,

[0052] Wherein:

[0053] Based on the total weight of the propylene-based impact copolymer, the content of the ethylene-propylene copolymer ranges from 23 to 35% by weight,

[0054] the propylene-based impact copolymer has a melt flow rate (230 °C / 2.16 kg) of 10 g / 10 min to 15 g / 10 min,

[0055] the polypropylene has a melt flow rate (230 °C / 2.16 kg) of 38 g / 10 min to 48 g / 10 min, and

[0056] in the ethylene-propylene copolymer, the molar ratio of the copolymer portion with the ethylene-derived unit content in the range of 45 - 55 mol% to the copolymer portion with the ethylene-derived unit content in the range of 20 - 30 mol% is 1.2 to 10.

[0057] In some embodiments, the present invention relates to a propylene-based impact copolymer comprising or consisting of the following:

[0058] (A) Polypropylene, preferably propylene homopolymer; and

[0059] (B) Ethylene-propylene copolymer,

[0060] wherein:

[0061] Based on the total weight of the propylene-based impact copolymer, the content of the ethylene-propylene copolymer ranges from 23 to 30% by weight,

[0062] the propylene-based impact copolymer has a melt flow rate (230 °C / 2.16 kg) of 10 g / 10 min to 15 g / 10 min,

[0063] the polypropylene has a melt flow rate (230 °C / 2.16 kg) of 38 g / 10 min to 48 g / 10 min, and

[0064] in the ethylene-propylene copolymer, the molar ratio of the copolymer portion with the ethylene-derived unit content in the range of 45 - 55 mol% to the copolymer portion with the ethylene-derived unit content in the range of 20 - 30 mol% is 1.2 to 5.

[0065] In some embodiments, the present invention relates to a propylene-based impact copolymer comprising or consisting of the following:

[0066] (A) Polypropylene, preferably propylene homopolymer; and

[0067] (B) Ethylene-propylene copolymer,

[0068] Wherein:

[0069] Based on the total weight of the propylene-based impact copolymer, the content of the ethylene-propylene copolymer ranges from 23 to 35% by weight.

[0070] The propylene-based impact copolymer has a melt flow rate (230 °C / 2.16 kg) of 10 g / 10 min to 15 g / 10 min.

[0071] The polypropylene has a melt flow rate (230 °C / 2.16 kg) of 38 g / 10 min to 48 g / 10 min, and

[0072] In the ethylene-propylene copolymer, the molar ratio of the copolymer portion with the ethylene-derived unit content in the range of 45 - 55 mol% to the copolymer portion with the ethylene-derived unit content in the range of 20 - 30 mol% is 1.2 to 5.

[0073] In some embodiments, the present invention relates to a propylene-based impact copolymer comprising or consisting of the following:

[0074] (A) Polypropylene, preferably propylene homopolymer; and

[0075] (B) Ethylene-propylene copolymer,

[0076] Wherein:

[0077] Based on the total weight of the propylene-based impact copolymer, the content of the ethylene-propylene copolymer ranges from 23 to 30% by weight.

[0078] The propylene-based impact copolymer has a melt flow rate (230 °C / 2.16 kg) of 10 g / 10 min to 15 g / 10 min.

[0079] The polypropylene has a melt flow rate (230 °C / 2.16 kg) of 38 g / 10 min to 48 g / 10 min, and

[0080] In the ethylene-propylene copolymer, the molar ratio of the copolymer portion with the ethylene-derived unit content in the range of 45 - 55 mol% to the copolymer portion with the ethylene-derived unit content in the range of 20 - 30 mol% is 1.2 to 3, preferably 1.5 to 2.5.

[0081] The propylene-based impact copolymer of the present invention is multiphase, in which the polypropylene component A forms a continuous phase, and the ethylene-propylene copolymer component B is dispersed as a rubber phase in the continuous phase. As used herein, multiphase means that the polymer has two or more phases. In the present invention, the copolymer component (component B) has rubber properties (rubber phase) and provides impact resistance, while the polypropylene component (component A) provides overall rigidity as a matrix.

[0082] These components of the propylene-based impact copolymer of the present invention can generally be produced in a sequential polymerization process, in which the polypropylene component A (such as a propylene homopolymer) produced in the first reactor is transferred to the second reactor, where the component B is produced and the component B is incorporated into the matrix of the component A. The propylene-based impact copolymer of the present invention can be a so-called reactor (or in-situ) blend or a post-reactor (ex-situ) blend.

[0083] The propylene-based impact copolymer of the present invention can be a reactor blend, which means that components A and B are not physically or mechanically blended together after polymerization, but are inter-polymerized in at least one reactor, usually in two or more series-connected reactors. In some other embodiments, the propylene-based impact copolymer described herein can also be formed as follows: Components A and B are prepared in separate reactors and physically blended once they leave their respective reactors.

[0084] Preferably, in the propylene-based impact copolymer of the present invention, the intrinsic viscosity ratio (IVR) of component B to component A is in the range of 1.0 to 5.0. For example, the intrinsic viscosity ratio of component B to component A can be 1.0, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, or the intrinsic viscosity ratio between any of these values. Preferably, the intrinsic viscosity ratio of component B to component A is in the range of 1.5 to 3.0, more preferably in the range of 1.5 to 2.5.

[0085] The glass transition temperature (Tg) is an indicator of the temperature at which a material changes from a rigid glassy state to a soft state. The lower the Tg, the better the impact resistance of the material at low temperatures. Component B, which is a rubber phase in the propylene-based impact copolymer of the present invention, can have a glass transition temperature Tg of -40°C to -60°C. For example, the glass transition temperature Tg of component B, which is a rubber phase in the propylene-based impact copolymer of the present invention, can be -40°C, -45°C, -50°C, -55°C, -60°C, or the glass transition temperature Tg between any of these values.

[0086] The propylene-based impact copolymer of the present invention not only has an improved rigidity-toughness balance at room temperature but also has improved low-temperature impact resistance.

[0087] Method for preparing a propylene-based impact copolymer

[0088] The method for preparing Component A polypropylene of the present invention is not critical and it can be manufactured by slurry, solution, gas phase or other suitable processes and by using a catalyst system suitable for olefin polymerization, such as Ziegler-Natta type catalysts, metallocene type catalysts, other suitable catalyst systems or combinations thereof. Preferably, solution or slurry polymerization is adopted, using Ziegler-Natta type catalysts.

[0089] Component B ethylene-propylene copolymer of the present invention can be prepared by slurry, solution, gas phase, high pressure or other suitable methods by using a catalyst system suitable for ethylene polymerization, such as Ziegler-Natta type catalysts, chromium catalysts, metallocene type catalysts, other suitable catalyst systems or combinations thereof, or by free radical polymerization.

[0090] Preferably, the propylene-based impact copolymer of the present invention can be prepared by conventional polymerization techniques, such as a two-step gas phase method catalyzed by Ziegler-Natta type catalysts. See, for example, U.S. Patent No. 4,379,759, which is hereby incorporated by reference in its entirety. Although sometimes impractical, the propylene-based impact copolymer of the present invention can be prepared in a single reactor. Preferably, the propylene-based impact copolymer of the present invention can also be prepared in reactors operating in series. In these series operations, the first polymerization (polymerization of Component A) is preferably a liquid slurry or solution polymerization method, and the second polymerization (polymerization of Component B) is preferably carried out in the gas phase. In one or more embodiments, hydrogen can be added to one or both reactors to control the molecular weight, intrinsic viscosity IV and / or MFR. The application of hydrogen for such purposes is well known to those skilled in the art.

[0091] Metallocene-based catalyst systems can also be used to prepare the propylene-based impact copolymer of the present invention. Currently particularly suitable metallocenes are those belonging to the genus of bridged, substituted bis(cyclopentadienyl) metallocenes known to be used to prepare high molecular weight, high melting point, highly isotactic propylene polymers, especially those belonging to the genus of bridged, substituted bis(indenyl) metallocenes. Generally, those belonging to the genus disclosed in U.S. Patent No. 5,770,753 (incorporated by reference in its entirety herein) are suitable.

[0092] In a preferred embodiment, the propylene-based impact copolymer of the present invention is prepared by a two-step sequential method, which uses a solution or slurry type polymerization method in the presence of a polymerization catalyst, and then the homopolymer-active catalyst is transferred to a gas phase reactor, where it is further contacted with ethylene and propylene to form copolymer domains within the continuous phase of the propylene homopolymer.

[0093] Use of the propylene-based impact copolymer

[0094] The propylene-based impact copolymer of the present invention achieves satisfactory performance characteristics, in particular, impact resistance over a wide temperature range, maintaining high impact resistance at room temperature and low temperatures (such as -20°C). Moreover, the propylene-based impact copolymer of the present invention maximizes the toughening efficiency of the rubber and improves the stiffness-toughness balance at room temperature. These advantages of the present invention make it potentially applicable to more applications. For example, the propylene-based impact copolymer of the present invention can be compounded with other components for various applications, such as applications in the automotive field, packaging field, and household appliance field.

[0095] The present invention thus also relates to the use of the propylene-based impact copolymer of the present invention, including for the manufacture of consumer goods, industrial products, building materials, packaging materials, and vehicle components, and particularly relates to the use of the propylene-based impact copolymer of the present invention in the production of automobiles, household appliances, and rigid packaging. For example, the propylene-based impact copolymer of the present invention can be directly used to prepare furniture or household appliance components, or can be used for the modification of automotive materials.

[0096] The propylene-based impact copolymer of the present invention can be formed into the desired end-use articles by any suitable method known in the art. They can be particularly used for manufacturing articles by blow molding, extrusion, injection molding, thermoforming, gas foaming, elastic welding, and compression molding techniques.

[0097] Non-limiting examples of desirable articles that can be made from the propylene-based impact copolymers of the present invention include rigid packaging (permanent and disposable), household appliances (washing machines, refrigerators, blenders, air conditioners, etc.), furniture (indoor and outdoor, such as tables, chairs, benches, shelves, etc.), sports equipment (skis, surfboards, skateboards, ice skates, boots, sleds, scooters, rafts, paddles, etc.), solid disc wheels, stadium seats, amusement park horse paths, personal protection equipment (safety helmets, shin guards, etc.), emergency response equipment, cookware, utensils, plates, pallets, carts, troughs, barrels, pool liners, storage containers (cases, buckets, cans, bottles, etc.), toys, child car seats and children's chairs, sanitary ware, sportswear, suitcases, instrument housings (for drill presses, saws, etc.), electronic device housings (for televisions, computers, telephones, handheld devices, media players, stereo systems, radios, clocks, etc.), building materials (floors, wall panels, ceiling panels, counter tops, electrical enclosures and connectors, etc.), luminaires, gardening equipment (shovel handles, wheelbarrow handles, etc.), sports field equipment, motor housings, pump housings, battery housings, meter housings, switches, knobs, buttons, handles, pet supplies, laboratory supplies, personal hygiene instruments (razors, brushes, hair dryers, etc.), cleaning supplies (brooms, dust pans, etc.), musical instrument cases, statues, awards, handicrafts, costume jewelry, picture frames, lens frames, plant pots, gun components and automotive components.

[0098] Other non-limiting examples of desirable articles that can be made from the propylene-based impact copolymers of the present invention and that are useful in vehicles (such as cars, trucks, buses, boats, all ground vehicles, personal watercraft, golf carts, snowmobiles, motorcycles, mopeds, tractors, lawn mowers, station wagons, bicycles, airplanes, helicopters, trains, military machinery, and vans, etc.) include: bumpers and bumper fascias; exterior body panels, door panels, grilles, exterior trim, body side moldings, wall panel claddings and moldings, end caps, hoods, deck lids, mirror housings, roof racks, wheel covers, wheel liners, wheel flares, fender liners, jack covers, wiring boards, step pads, sill plates, air dam, splash guards, mud flaps, bed liners, and rocker panels; fuel tanks; interior trim panels, steering column shrouds, consoles, door panels, pillars, braces, knobs, buttons, handles, and safety screens; instrument panels and control panels; knee pads; passenger side airbag covers; header makers; glove boxes, trays, cup holders, compartments, and covers; seat assemblies, backings, braces, and seat belt latches; underhood applications, battery trays, and fan shrouds; electrical enclosures; cable bearings; and structural components, door carriers, truck bed dividers, load floors, and trunk dividers.

[0099] Embodiments of the present invention

[0100] Overall, the present invention can relate to the following embodiments.

[0101] 1. An impact copolymer based on propylene, comprising or consisting of the following:

[0102] (A) Polypropylene; and

[0103] (B) An ethylene-propylene copolymer,

[0104] wherein:

[0105] Based on the total weight of the propylene-based impact copolymer, the content of the ethylene-propylene copolymer is greater than or equal to 20% by weight, preferably greater than or equal to 23% by weight, more preferably in the range of 23 to 35% by weight,

[0106] The propylene-based impact copolymer has a melt flow rate (230 °C / 2.16 kg) of 8 g / 10 min to 20 g / 10 min, preferably 10 g / 10 min to 15 g / 10 min,

[0107] The polypropylene has a melt flow rate (230 °C / 2.16 kg) of 35 g / 10 min to 55 g / 10 min, preferably 38 g / 10 min to 48 g / 10 min, and

[0108] In the ethylene-propylene copolymer, the molar ratio of the copolymer portion with the content of ethylene-derived units in the range of 45 - 55 mol% to the copolymer portion with the content of ethylene-derived units in the range of 20 - 30 mol% is 1.2 or more.

[0109] 2. The propylene-based impact copolymer according to embodiment 1, wherein the polypropylene is a propylene homopolymer.

[0110] 3. The propylene-based impact copolymer according to embodiment 1 or 2, wherein based on the total weight of the propylene-based impact copolymer, the content of the polypropylene is in the range of 60 to 80% by weight, preferably in the range of 65 to 77% by weight, for example in the range of 70 to 77% by weight.

[0111] 4. The propylene-based impact copolymer according to any one of embodiments 1 to 3, wherein the polypropylene forms a continuous phase and the ethylene-propylene copolymer is dispersed in the continuous phase.

[0112] 5. The propylene-based impact copolymer according to any one of embodiments 1 to 4, wherein in the ethylene-propylene copolymer, the molar ratio of the copolymer portion with the content of ethylene-derived units in the range of 45 - 55 mol% to the copolymer portion with the content of ethylene-derived units in the range of 20 - 30 mol% is 1.2 to 10, preferably 1.2 to 5, more preferably 1.2 to 3, for example 1.5 to 2.5.

[0113] 6. The propylene-based impact copolymer according to any one of embodiments 1 to 5, wherein the intrinsic viscosity ratio of component B to component A is in the range of 1.0 to 5.0, preferably in the range of 1.5 to 3.0, more preferably in the range of 1.5 to 2.5.

[0114] 7. The propylene-based impact copolymer according to any one of embodiments 1 to 6, wherein component B has a glass transition temperature Tg of -40°C to -60°C.

[0115] 8. A propylene-based impact copolymer comprising or consisting of the following:

[0116] (A) Polypropylene, preferably a propylene homopolymer; and

[0117] (B) An ethylene-propylene copolymer,

[0118] wherein:

[0119] Based on the total weight of the propylene-based impact copolymer, the content of the ethylene-propylene copolymer is in the range of 23 to 30% by weight,

[0120] The propylene-based impact copolymer has a melt flow rate (230°C / 2.kg) of 10 g / 10 min to 15 g / 10 min,

[0121] The polypropylene has a melt flow rate (230°C / 2.kg) of 38 g / 10 min to 48 g / 10 min, and

[0122] In the ethylene-propylene copolymer, the molar ratio of the copolymer portion with the content of ethylene-derived units in the range of 45 - 55 mol% to the copolymer portion with the content of ethylene-derived units in the range of 20 - 30 mol% is 1.5 to 2.5.

[0123] 9. Use of the propylene-based impact copolymer according to any one of embodiments 1 to 8 in automotive, household appliances and rigid packaging.

[0124] 10. An article obtained from the propylene-based impact copolymer according to any one of embodiments 1 to 8.

[0125] 11. The article according to embodiment 10, wherein the article is a household appliance, furniture, vehicle component.

[0126] Examples

[0127] The present invention and its effects are further elaborated by the following examples. These examples are for illustrative purposes and should not be construed as limiting the present invention. The ratios or percentages given in the examples are by weight unless otherwise specified.

[0128] Test method

[0129] In this specification and the examples, the characterization and test methods of the performance parameters involved are described as follows.

[0130] Weight-average molecular weight and molecular weight distribution:

[0131] The weight-average molecular weight and molecular weight distribution were determined by gel permeation chromatography (GPC) calibrated using polystyrene (PS) as the standard. The measurement was carried out by gel permeation chromatography using trichlorobenzene as the eluent (flow rate: 1 mL / min; injection volume: 200 μL).

[0132] Melt flow rate (MFR)

[0133] The melt flow rate (MFR) was measured according to the standard method of ASTM D1238, 230 °C / 2.16 kg.

[0134] Flexural modulus

[0135] The flexural modulus was measured according to the standard method of ISO 178.

[0136] Notched Izod impact strength

[0137] The notched Izod impact strength was measured according to the standard method of ISO 180 / 1eA.

[0138] Intrinsic viscosity

[0139] The intrinsic viscosity was measured according to DIN EN ISO 1628 / 1 (135 °C, in decalin). In the examples, IVR is the ratio of the intrinsic viscosity of component B to that of component A.

[0140] Glass transition temperature Tg

[0141] The glass transition temperature (T g)。This test provides information on the small-strain mechanical response of a sample as a function of temperature in a temperature range that includes the glass transition region and the viscoelastic region prior to melting. The specimens were tested using a commercially available DMA instrument (TA Instruments DMA 2980) equipped with a double cantilever test fixture. The specimens were cooled to -130 °C and then heated to 60 °C at a heating rate of 2 °C / min while undergoing oscillatory deformation at 0.1% strain and 1 rad / sec frequency. The output of these DMA experiments is the storage modulus (E′) and the loss modulus (E″). The storage modulus measures the elastic response or the ability of the material to store energy, and the loss modulus measures the viscous response or the ability of the material to dissipate energy. The ratio of E″ / E′ (referred to as Tanδ) gives a measure of the damping ability of the material; the peaks in Tanδ are related to the relaxation modes of the material. T g is defined as the peak temperature related to the β relaxation mode, which for polyolefins typically exists in the temperature range of -80 to +20 °C. In a multiphase blend, the independent β relaxation modes of each blend component may result in more than one T g being detected for the blend; when each component is similarly analyzed by DMA, the assignment of T g for each component is preferably based on the observed T g (although small temperature offsets are possible).

[0142] Cv and Gv

[0143] Cv (content of component B in the impact copolymer) and Gv (content of ethylene-derived units in component B of the impact copolymer) were measured by Fourier transform infrared test instrument calibrated by high-field nuclear magnetic resonance and low-field nuclear magnetic resonance.

[0144] High performance liquid chromatography - size exclusion chromatography (HPLC-SEC)

[0145] Copolymers containing multiple components such as impact polypropylene (ICP) were separated into components by the difference in the dissolution gradient of the different components in trichlorobenzene, and the number of methyl groups per thousand carbons of each component was detected by an infrared detector in a tandem size exclusion chromatography (SEC) (flow rate: 3 mL / min).

[0146] Polymer preparation

[0147] The propylene-based impact copolymers of the examples were prepared by the following method to obtain impact copolymer samples PP1 (comparative sample) and PP2 (sample of the present invention).

[0148] Polypropylene is prepared in a continuous commercial-scale reactor of the bulk type. The magnesium chloride-supported titanium catalyst is supplied by Toho Titanium Company, and the catalyst solid is used together with an external donor described in U.S. Patent 6,087,495. The donor system is a blend of dicyclopentyldimethoxysilane and propyltriethoxysilane. The preparation of the catalyst system is carried out continuously in situ as follows: The catalyst solid, triethylaluminum, and the donor system are contacted under conditions known in the art to produce an active, stereospecific catalyst system for propylene polymerization. The activated catalyst system is continuously fed to a prepolymerization reactor, where it continuously polymerizes propylene at a productivity of about 100 - 400 g-polymer / g-cat. Then the prepolymerized catalyst system is continuously fed to a bulk slurry reactor and polymerization is continued at 70°C - 80°C for a residence time of about 50 minutes. The melt flow rate of the polypropylene homopolymer resin is controlled using hydrogen in the reactor according to the design of the melt flow rate (MFR) of Component A.

[0149] The reaction slurry is withdrawn from the reactor and the homopolymer particles are continuously separated from liquid propylene and then fed into a gas-phase reactor.

[0150] The particles after removing the monomer from the bulk reactor are fed to a gas-phase reactor (GPR), where polymerization continues under conditions known in the art to produce an ethylene-propylene copolymer within the interstitial pores of the homopolymer particles. The composition of the ethylene-propylene copolymer is controlled by controlling the catalyst activity in the gas-phase reactor, and the molecular weight of the ethylene-propylene copolymer or more appropriately, the intrinsic viscosity (IV) of the rubber phase is controlled. Impact copolymer samples PP1 and PP2 with the parameters shown in Table 1 are obtained.

[0151] The final product is continuously discharged from the gas-phase reactor to obtain PP1 and PP2.

[0152] Table 1. Corresponding characteristics of impact copolymer samples

[0153]

[0154] The obtained samples are subjected to HPLC-SEC testing and analyzed according to the obtained peak results. Component B of the composition is analyzed according to the peak area integration results, and the molar ratio of the copolymer portion with ethylene-derived units in the range of 45 - 55 mol% to the copolymer portion with ethylene-derived units in the range of 20 - 30 mol% is calculated. Among them, the mole fraction of ethylene-derived units is converted according to the number of methyl groups per thousand carbons, and its calculation formula is as follows:

[0155]

[0156] Where:

[0157] n is the number of methyl groups per thousand carbons (the number of methyl groups per thousand carbons in each polymer chain).

[0158] C2 represents units derived from ethylene.

[0159] The results are listed in Table 2.

[0160] Table 2. HPLC-SEC result analysis

[0161]

[0162] Performance tests were conducted on samples PP1 and PP2. The results are listed in Table 3.

[0163] Table 3. Performance test results

[0164]

[0165] *In the Izod test, P indicates partial fracture. C indicates complete fracture.

[0166] The glass transition temperature (Tg) is an indicator of the temperature at which a material changes from a rigid glassy state to a soft state. The lower the Tg, the better the impact resistance of the rubber at low temperatures. The results in Table 3 show that the impact copolymer PP2 of the present invention achieves a Tg below -55°C.

[0167] The notched Izod impact strength is a key indicator for measuring the toughness of a material, while the flexural modulus is a key indicator for measuring rigidity. The balance between rigidity and toughness has always been a performance pursued by propylene-based impact copolymers (ICPs).

[0168] As can be seen from Table 3, PP1 and PP2 have similar MFRs at room temperature (23°C), but PP2 achieves a higher notched Izod impact strength than PP1. From Tables 2 and 3, it can be seen that PP1 and PP2 have similar contents of component B, but the copolymer part of the ethylene-derived units in component B of PP2 is more in the range of 45 - 55 mol% than the corresponding copolymer part in component B of PP1, resulting in a lower Tg value and a higher impact strength at low temperature (-20°C) than PP1. In addition, PP2 shows a higher flexural modulus.

[0169] Based on the above data, it can be seen that PP2 has a better balance between rigidity and toughness at room temperature and higher low-temperature impact resistance at -20°C. This makes the propylene-based impact copolymer of the present invention potentially applicable to a variety of applications.

Claims

1. An impact copolymer based on propylene, comprising or consisting of the following: (A) Polypropylene, wherein the polypropylene is a propylene homopolymer; and (B) An ethylene-propylene copolymer, wherein: The polypropylene forms a continuous phase, and the ethylene-propylene copolymer is dispersed in the continuous phase, Based on the total weight of the propylene-based impact copolymer, the content of the polypropylene is in the range of 65 to 77% by weight, Based on the total weight of the propylene-based impact copolymer, the content of the ethylene-propylene copolymer is in the range of 23 to 35% by weight, The propylene-based impact copolymer has a melt flow rate measured at 230 °C / 2.16 kg in the range of 8 g / 10 min to 15 g / 10 min, The polypropylene has a melt flow rate measured at 230 °C / 2.16 kg in the range of 42 g / 10 min to 48 g / 10 min, and In the ethylene-propylene copolymer, the molar ratio of the copolymer portion with the content of ethylene-derived units in the range of 45 - 55 mol% to the copolymer portion with the content of ethylene-derived units in the range of 20 - 30 mol% is 1.5 to 3.

2. The propylene-based impact copolymer according to claim 1, wherein the propylene-based impact copolymer has a melt flow rate measured at 230 °C / 2.16 kg in the range of 10 g / 10 min to 15 g / 10 min.

3. The propylene-based impact copolymer according to claim 1 or 2, wherein based on the total weight of the propylene-based impact copolymer, the content of the polypropylene is in the range of 70 to 77% by weight.

4. The propylene-based impact copolymer according to claim 1 or 2, wherein in the ethylene-propylene copolymer, the molar ratio of the copolymer portion with the content of ethylene-derived units in the range of 45 - 55 mol% to the copolymer portion with the content of ethylene-derived units in the range of 20 - 30 mol% is 1.5 to 2.

5.

5. The propylene-based impact copolymer according to claim 1 or 2, wherein the ratio of the intrinsic viscosity of component B to that of component A is in the range of 1.0 to 5.

0.

6. The propylene-based impact copolymer according to claim 5, wherein the ratio of the intrinsic viscosity of component B to that of component A is in the range of 1.5 to 3.

0.

7. The propylene-based impact copolymer according to claim 5, wherein the ratio of the intrinsic viscosity of component B to that of component A is in the range of 1.5 to 2.

5.

8. The propylene-based impact copolymer according to claim 1 or 2, wherein component B has a glass transition temperature Tg of -40 °C to -60 °C.

9. An impact copolymer based on propylene, comprising or consisting of the following: (A) Polypropylene, wherein the polypropylene is a propylene homopolymer; and (B) An ethylene-propylene copolymer, wherein: The polypropylene forms a continuous phase, and the ethylene-propylene copolymer is dispersed in the continuous phase, Based on the total weight of the propylene-based impact copolymer, the content of the polypropylene is in the range of 70 to 77% by weight, Based on the total weight of the propylene-based impact copolymer, the content of the ethylene-propylene copolymer is in the range of 23 to 30% by weight. The propylene-based impact copolymer has a melt flow rate measured at 230 °C / 2.16 kg in the range of 10 g / 10 min to 15 g / 10 min. The polypropylene has a melt flow rate measured at 230 °C / 2.16 kg in the range of 42 g / 10 min to 48 g / 10 min, and In the ethylene-propylene copolymer, the molar ratio of the copolymer portion with the content of ethylene-derived units in the range of 45-55 mol% to the copolymer portion with the content of ethylene-derived units in the range of 20-30 mol% is 1.5 to 2.

5.

10. Use of the propylene-based impact copolymer according to any one of claims 1 to 9 in automobiles, household appliances and rigid packaging.

11. An article obtained from the propylene-based impact copolymer according to any one of claims 1 to 9.

12. The article according to claim 11, wherein the article is a household appliance, furniture, or vehicle component.

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