Propylene-based impact polymers and their preparation and use

Abstract

The present invention relates to a propylene-based impact copolymer comprising (A) a polypropylene and (B) an ethylene-propylene copolymer wherein the ethylene-propylene copolymer content is greater than or equal to 20% by weight, based on the total weight of the propylene-based impact copolymer, the propylene-based impact copolymer having a melt flow rate (230 DEG C / 2.16 kg) of from 8 g / 10 min to 20 g / 10 min, the polypropylene has a melt flow rate (230 DEG C / 2.16 kg) of 35 g / 10 min to 55 g / 10 min, and the molar ratio of a copolymer fraction having an ethylene-derived unit content in the range of 45-55 mol% to a copolymer fraction having an ethylene-derived unit content in the range of 20-30 mol% in the ethylene-propylene copolymer is 1.2 or more. The invention also relates to the use of the impact copolymer. The impact copolymer not only has improved rigidity-toughness balance at room temperature, but also has improved low-temperature impact resistance, and can be suitable for various applications.

Description

Technical Field

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

[0002] Propylene-based impact copolymer (ICP) is a multiphase polymer blend in which polypropylene (PP) is the matrix (continuous phase) and ethylene-propylene copolymer (EPR) is the dispersed phase (rubber phase), in which the rubber phase plays a toughening role. ICP materials are widely used in various fields of industry and social life, including automobiles, home appliances, and rigid packaging. These different application fields have different performance requirements for ICP materials, such as the need for ICP materials to be suitable for a wide temperature range from high to low temperatures. Usually one grade / specification of ICP cannot cover all application areas, which leads to increased costs for customers and raw material suppliers when using or producing them. In addition, as lightweighting becomes a development trend in various fields, the requirements for material toughness are also getting higher and higher. This poses further challenges to the development of polypropylene impact copolymers.

[0003] Therefore, it is necessary to provide a propylene-based impact copolymer, which can achieve improved performance at both room temperature and low temperature, not only having an improved rigidity-toughness balance at room temperature, but also having improved low-temperature impact resistance, meeting the performance requirements of propylene-based impact copolymers at room temperature and low temperatures. Summary of the invention

[0004] In order to solve the problems in the prior art, the present invention provides a propylene-based impact copolymer. The propylene-based impact copolymer 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, which makes it suitable for a variety of applications.

[0005] A main aspect of the present invention relates to a propylene-based impact copolymer comprising or consisting of:

[0006] (A) polypropylene; and

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

[0008] in:

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

[0010] 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,

[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 and above.

[0013] The present invention also relates to a method for preparing the propylene-based impact copolymer, uses of the propylene-based impact copolymer, and articles 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 rubber phase glass transition temperature (Tg), and in particular, achieves impact resistance over a wide temperature range, maintaining high impact resistance at room temperature and low temperature (e.g., -20°C). Moreover, the propylene-based impact copolymer of the present invention maximizes the toughening efficiency of the rubber and improves the rigidity-toughness balance at room temperature. These advantages of the present invention make it possible to be suitable for more applications. DETAILED DESCRIPTION

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

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

[0017] As used herein, a heterogeneous 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 packets (finely dispersed regions) dispersed in a matrix of the other polymer can be said to be heterogeneous in the solid state. The so-called continuous phase refers to the matrix phase in the heterogeneous blend, and the so-called discontinuous phase refers to the dispersed phase in the heterogeneous blend.

[0018] Propylene-based impact copolymers

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

[0020] (A) polypropylene; and

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

[0022] in:

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

[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 / 2.16kg) of 35 to 55 g / 10 min, preferably 38 to 48 g / 10 min, and

[0026] 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 and above.

[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 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, the remainder being propylene derived units, most preferably refers to a polymer consisting of propylene derived units. Olefins having a double bond in a terminal position are referred to herein as α-olefins.

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

[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 wt%, for example, its content is 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, or any value therebetween, preferably in the range of 65 to 80 wt%, more preferably in the range of 65 to 77 wt%, for example, in the range of 70 to 77 wt%.

[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 copolymerization of ethylene and propylene.

[0035] In the ethylene-propylene copolymer suitable for use as component B of the present invention, 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 and above. For example, 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 and above, 1.3 and above, 1.4 and above, 1.5 and above, 1.6 and above, 1.7 and above, 1.8 and above, 1.9 and above, 2 and above, 2.2 and above, 2.4 and above, 2.5 and above, 2.8 and above, 3 and above, 3.5 and above, 4 and above, 4.5 and above, 5 and above, 6 and above, 7 and above, 8 and above, 9 and above, 10 and above, 15 and above, or any number between these values. Preferably, in the ethylene-propylene copolymer suitable for use as component B of the present invention, the molar ratio of the copolymer part having an ethylene-derived unit content in the range of 45-55 mol% to the copolymer part having an ethylene-derived unit content 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.

[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 any value between these values.

[0038] In the propylene-based impact copolymer of the present invention, the content of ethylene-propylene copolymer is greater than or equal to 20% by weight, such as greater than or equal to 23% by weight, based on the total weight of the propylene-based impact copolymer. For example, based on the total weight of the propylene-based impact copolymer, the content of 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 ethylene-propylene copolymer is in the range of 23 to 35% by weight, such as 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 is directed to a propylene-based impact copolymer comprising or consisting of:

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

[0043] (B) an ethylene-propylene copolymer,

[0044] in:

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

[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 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 and above.

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

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

[0051] (B) an ethylene-propylene copolymer,

[0052] in:

[0053] The content of ethylene-propylene copolymer is in the range of 23 to 35 weight percent based on the total weight of the propylene-based impact copolymer,

[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 part having an ethylene-derived unit content in the range of 45-55 mol% to the copolymer part having an ethylene-derived unit content in the range of 20-30 mol% is 1.2 to 10.

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

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

[0059] (B) an ethylene-propylene copolymer,

[0060] in:

[0061] The content of ethylene-propylene copolymer is in the range of 23 to 30 wt % based on the total weight of the propylene-based impact copolymer,

[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 part having an ethylene-derived unit content in the range of 45-55 mol% to the copolymer part having an ethylene-derived unit content in the range of 20-30 mol% is 1.2 to 5.

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

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

[0067] (B) an ethylene-propylene copolymer,

[0068] in:

[0069] The content of ethylene-propylene copolymer is in the range of 23 to 35 weight percent based on the total weight of the propylene-based impact copolymer,

[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 part having an ethylene-derived unit content in the range of 45-55 mol% to the copolymer part having an ethylene-derived unit content in the range of 20-30 mol% is 1.2 to 5.

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

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

[0075] (B) an ethylene-propylene copolymer,

[0076] in:

[0077] The content of ethylene-propylene copolymer is in the range of 23 to 30 wt % based on the total weight of the propylene-based impact copolymer,

[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 part having an ethylene-derived unit content in the range of 45-55 mol% to the copolymer part having an 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 heterogeneous, wherein the polypropylene component A forms a continuous phase, and the ethylene-propylene copolymer component B is dispersed in the continuous phase as a rubber phase. Heterogeneous as used herein refers to 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 copolymers of the present invention can generally be produced in a sequential polymerization process, where the polypropylene component A (e.g., propylene homopolymer) produced in a first reactor is transferred to a second reactor where component B is produced and incorporated into the matrix of component A. The propylene-based impact copolymers of the present invention can be so-called reactor (or in-situ) blends or post-reactor (ex-situ) blends.

[0083] The propylene-based impact copolymers of the present invention can be reactor blends, which means that components A and B are not physically or mechanically blended together after polymerization, but are interpolymerized in at least one reactor, typically two or more reactors in series. In some other embodiments, the propylene-based impact copolymers described herein can also be formed by preparing components A and B in separate reactors and physically blending these components 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 any intrinsic viscosity ratio between 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] 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 as the rubber phase in the propylene-based impact copolymer of the present invention may have a glass transition temperature Tg of -40°C to -60°C. For example, the glass transition temperature Tg of component B as the rubber phase in the propylene-based impact copolymer of the present invention may be -40°C, -45°C, -50°C, -55°C, -60°C, or a glass transition temperature Tg between any of these values.

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

[0087] Process for preparing propylene-based impact copolymers

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

[0089] The component B ethylene-propylene copolymer of the present invention can be prepared by slurry, solution, gas phase, high pressure or other suitable processes 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, for example, a two-step gas phase process catalyzed by a Ziegler-Natta type catalyst. See, for example, U.S. Patent No. 4,379,759, which is incorporated herein 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 a reactor operated in series. In these series operations, the first polymerization (polymerization of component A) is preferably a liquid slurry or solution polymerization process, 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 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 copolymers of the present invention. Currently particularly suitable metallocenes are those belonging to the class of bridged, substituted bis(cyclopentadienyl)metallocenes, particularly bridged, substituted bis(indenyl)metallocenes known to prepare high molecular weight, high melting point, highly isotactic propylene polymers. In general, those belonging to the class disclosed in U.S. Patent No. 5,770,753 (incorporated herein by reference in its entirety) are suitable.

[0092] In a preferred embodiment, the propylene-based impact copolymers of the present invention are prepared in a two-step sequential process using a solution or slurry type polymerization process in the presence of a polymerization catalyst, followed by transferring the homopolymer-active catalyst to a gas phase reactor wherein it is further contacted with ethylene and propylene to form copolymer domains within a continuous phase of propylene homopolymer.

[0093] Uses of propylene-based impact copolymers

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

[0095] The present invention therefore also relates to the use of the propylene-based impact copolymer of the present invention, including use in the manufacture of consumer goods, industrial products, building materials, packaging materials and vehicle parts, and in particular 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 parts, and can also be used for the modification of automotive materials.

[0096] The propylene-based impact copolymers of the present invention can be formed into desired end-use articles by any suitable method known in the art. They are particularly useful for making 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 (durable and disposable), household appliances (washing machines, refrigerators, blenders, air conditioners, etc.), furniture (indoor and outdoor, such as tables, chairs, benches, shelves, etc.), sporting equipment (skis, surfboards, skates, skates, boots, sleds, scooters, rafts, paddles, etc.), integral disc wheels, stadium seating, amusement park riding trails, personal protective equipment (helmets, shin guards, etc.), emergency response equipment, cookware, utensils, dishes, pallets, carts, troughs, barrels, pool liners, storage containers (boxes, buckets, cans, bottles, etc.), toys, child car seats and child chairs, hygiene equipment, sportswear, Luggage, instrument housings (for drill presses, saws, etc.), electronic equipment housings (for televisions, computers, telephones, handheld devices, media players, stereo systems, radios, clocks, etc.), building materials (floors, wall panels, ceiling panels, counter covers, electrical housings and connectors, etc.), luminaires, gardening equipment (shovel handles, wheelbarrow handles, etc.), playground equipment, motor housings, pump housings, battery housings, instrument housings, switches, knobs, buttons, handles, pet supplies, laboratory supplies, personal hygiene equipment (razors, brushes, hair dryers, etc.), cleaning supplies (brooms, dust pans, etc.), musical instrument cases, statues, awards, crafts, costume jewelry, picture frames, lens frames, plant pots, gun components, and automobile components.

[0098] Other non-limiting examples of desirable articles useful in vehicles (e.g., cars, trucks, buses, boats, all land vehicles, personal watercraft, golf carts, snowmobiles, motorcycles, mopeds, tractors, lawn mowers, station wagon bicycles, airplanes, helicopters, trains, military machinery and vans, etc.) that can be made from the propylene-based impact copolymers of the present invention include: bumpers and bumper trays; exterior body panels, door panels, grills, exterior trim, body side moldings, wall panel cladding and moldings, end caps, hoods, deck covers, mirror housings, luggage racks, wheel covers, wheel liners interior trim panels, steering column covers, consoles, door panels, pillars, bolsters, knobs, buttons, handles and safety screens; instrument panels and control panels; knee bolsters; passenger-side air bag covers; title makers; glove boxes, trays, cup holders, compartments and covers; seat assemblies, backings, bolsters and seat belt latches; underhood applications, battery trays and fan guards; electrical enclosures; cable bearings; and structural assemblies, door brackets, truck bed bulkheads, load boards and trunk dividers.

[0099] Embodiments of the present invention

[0100] In general, the present invention may relate to the following embodiments.

[0101] 1. A propylene-based impact copolymer comprising or consisting of:

[0102] (A) polypropylene; and

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

[0104] in:

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

[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 / 2.16kg) of 35 to 55 g / 10 min, preferably 38 to 48 g / 10 min, and

[0108] 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 and above.

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

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

[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. A 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 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 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, and 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:

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

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

[0118] in:

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

[0120] 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,

[0121] The polypropylene has a melt flow rate (230° C. / 2.16 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 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 1.5 to 2.5.

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

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

[0125] 11. The article of embodiment 10, wherein the article is a household appliance, furniture, or a vehicle part.

[0126] Example

[0127] The present invention and its effects are further described 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 examples, the characterization and testing 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) using polystyrene (PS) as standard after calibration. The measurements were performed by gel permeation chromatography using trichlorobenzene as eluent (flow rate: 1 mL / min; injection volume: 200 μl).

[0132] Melt flow rate (MFR)

[0133] Melt flow rate (MFR) is measured according to ASTM D1238, 230°C / 2.16kg standard method.

[0134] Flexural modulus

[0135] Flexural modulus is measured according to ISO 178 standard method.

[0136] Notched Izod impact strength

[0137] Notched Izod impact strength is measured according to ISO 180 / 1eA standard method.

[0138] Intrinsic viscosity

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

[0140] Glass transition temperature Tg

[0141] The glass transition temperature (T) was measured using dynamic mechanical analysis. g). This test provides information about the small strain mechanical response of the sample as a function of temperature over 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 dual 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 a frequency of 1 rad / sec. The outputs of these DMA experiments are the storage modulus (E') and the loss modulus (E"). The storage modulus measures the elastic response of the material, or its ability to store energy, and the loss modulus measures the viscous response of the material, or its ability to dissipate energy. The ratio of E" / E' (called Tan δ) gives a measure of the damping capacity of the material; peaks in Tan δ are associated with the relaxation modes of the material. T g Defined as the peak temperature associated with the β relaxation mode, for polyolefins it typically occurs in the temperature range of -80 to +20°C. In a heterogeneous blend, the independent β relaxation modes of each blend component may result in more than one T being detected for the blend. g When the components were similarly analyzed by DMA, the T g The assignment is preferably based on the observed T g (However small temperature excursions 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 testing 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 by the difference in the solubility gradient of different components in trichlorobenzene, and the number of carbon methyl groups of each component was detected by an infrared detector of 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 (inventive sample).

[0148] Polypropylene is prepared in a bulk continuous commercial line scale reactor. A 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 catalyst system preparation is carried out in situ and continuously as follows: the catalyst solid, triethylaluminum and the donor system are contacted under conditions known in the art to produce an active, stereoregular catalyst system for propylene polymerization. The activated catalyst system is continuously supplied to a prepolymerization reactor, where it continuously polymerizes propylene to a productivity of about 100-400 g-polymer / g-cat. The prepolymerized catalyst system is then continuously supplied 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 in the reactor using hydrogen according to the melt flow rate (MFR) design for component A.

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

[0150] The particles from the bulk reactor after the removal of monomers are fed to a gas phase reactor (GPR) where polymerization continues under conditions known in the art to produce ethylene-propylene copolymers within the interstitial pores of the homopolymer particles. The molecular weight of the ethylene-propylene copolymer or more appropriately, the intrinsic viscosity (IV) of the rubber phase is controlled by controlling the catalyst activity in the gas phase reactor to control the composition of the ethylene-propylene copolymer. The impact copolymer samples PP1 and PP2 having 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 were subjected to HPLC-SEC test, and the obtained peak results were used to analyze the samples. The component B of the composition was analyzed based on the peak area integration results, and the molar ratio of the copolymer part with ethylene-derived units in the range of 45-55 mol% to the copolymer part with ethylene-derived units in the range of 20-30 mol% was calculated. The molar fraction of the ethylene-derived units was calculated based on the number of thousand carbon methyl groups, and the calculation formula is as follows:

[0155]

[0156] in:

[0157] n is the number of methyl groups per thousand carbon atoms (the number of methyl groups per thousand carbon atoms in each polymer chain),

[0158] C2 represents an ethylene-derived unit.

[0159] The results are listed in Table 2.

[0160] Table 2. HPLC-SEC results analysis

[0161]

[0162] The performance of samples PP1 and PP2 was tested and the results are listed in Table 3.

[0163] Table 3. Performance test results

[0164]

[0165] *In the Izod test, P means partial breakage and C means complete breakage.

[0166] Glass transition temperature (Tg) is the temperature at which a material changes from a rigid glass 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] Notched Izod impact strength is a key indicator of material toughness, while flexural modulus is a key indicator of rigidity. Rigidity-toughness balance has always been the performance pursued by propylene-based impact copolymers (ICP).

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

[0169] According to the above data, PP2 has a better rigidity-toughness balance at room temperature and has higher low-temperature impact resistance at -20° C. This makes the propylene-based impact copolymer of the present invention potentially suitable for a variety of applications.

Claims

1. A propylene-based impact copolymer comprising or consisting of: (A) polypropylene; and (B) an ethylene-propylene copolymer, in: The content of ethylene-propylene copolymer is greater than or equal to 20 wt%, preferably greater than or equal to 23 wt%, more preferably in the range of 23 to 35 wt%, based on the total weight of the propylene-based impact copolymer, 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, The polypropylene has a melt flow rate (230°C / 2.16kg) of 35 to 55 g / 10 min, preferably 38 to 48 g / 10 min, and 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 and above.

2. The propylene-based impact copolymer of claim 1, wherein the polypropylene is a propylene homopolymer.

3. The propylene-based impact copolymer according to claim 1 or 2, wherein the content of the polypropylene is in the range of 60 to 80 wt%, preferably in the range of 65 to 77 wt%, such as in the range of 70 to 77 wt%, based on the total weight of the propylene-based impact copolymer.

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

5. The propylene-based impact copolymer according to any one of claims 1 to 4, wherein 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 to 10, preferably 1.2 to 5, more preferably 1.2 to 3, for example 1.5 to 2.

5.

6. The propylene-based impact copolymer according to any one of claims 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, and more preferably in the range of 1.5 to 2.

5.

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

8. A propylene-based impact copolymer comprising or consisting of: (A) polypropylene, preferably a propylene homopolymer; and (B) an ethylene-propylene copolymer, in: The content of ethylene-propylene copolymer is in the range of 23 to 30 wt % based on the total weight of the propylene-based impact copolymer, 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, The polypropylene has a melt flow rate (230° C. / 2.16 kg) of 38 g / 10 min to 48 g / 10 min, and 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 1.5 to 2.

5.

9. Use of the propylene-based impact copolymer according to any one of claims 1 to 8 in automobiles, household appliances and rigid packaging.

10. An article obtained from the propylene-based impact copolymer according to any one of claims 1 to 8.

11. The article of claim 10, wherein the article is a household appliance, furniture, or a vehicle component.

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