Propylene-based copolymer, process for its preparation and use

Abstract

The present application provides a propylene-based copolymer, a preparation method and application thereof, the weight average molecular weight of the propylene-based copolymer is 2.0*10 4 -40.0*10 4 g / mol, the density is 0.860-0.890 g / cm 3 -3; the gamma value of the propylene-based copolymer is greater than or equal to 80%. Through the design of specific molecular weight, density and gamma value, the regulation of material structure and composition is realized. The propylene-based copolymer is used for polyolefin film material, can effectively reduce the sealing temperature, widen the heat sealing temperature range, and make the polyolefin film containing the same have significantly improved heat sealing performance.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, particularly the field of polyolefins, and specifically relates to a propylene-based copolymer, its preparation method, and its application. Background Technology

[0002] Polypropylene (PP) is a type of polyolefin material. It is transparent and lightweight, and possesses excellent chemical resistance, high-temperature resistance, electrical insulation, and abrasion resistance. It is widely used in food and pharmaceutical packaging, automotive parts, clothing, daily necessities, and fiber products. With the increasing pursuit of a higher standard of living, the consumption of polypropylene film for food packaging is increasing year by year. From a technological perspective, the most common polypropylene packaging film material is cast polypropylene film (CPP cast film), which is a non-stretched, non-oriented flat extruded film produced through melt casting and rapid cooling. It features good transparency, high gloss, good stiffness, good moisture barrier properties, and excellent heat resistance. The production process of CPP cast film includes: feeding, batching and weighing, melt extrusion, thickness measurement, edge trimming, corona treatment, traction, winding, slitting, packaging, and warehousing.

[0003] Depending on their functionality, traditional CPP cast films can have three or more layers. The heat-sealing layer primarily functions to heat and bond the film during the sealing process. Key performance indicators for the heat-sealing layer typically include heat-sealing strength, initial sealing temperature, and the heat-sealing temperature range. Appropriate heat-sealing strength ensures a strong seal, preventing the packaging bag from opening and spilling its contents during transport and transfer. A lower initial sealing temperature reduces packaging energy consumption and improves sealing efficiency. However, lower initial sealing temperatures result in a softer film material, making it more prone to self-adhesion and unstable opening performance, potentially even causing production line shutdowns. Furthermore, excellent heat-sealing performance also includes a suitable heat-sealing temperature range, aiming to ensure a proper seal without causing the film to thin and wrinkle at the seal, thus affecting heat-sealing strength and aesthetics.

[0004] Studies have shown that heat-sealing films prepared by incorporating low-melting-point polyolefin elastomers into crystalline polypropylene can reduce heat-sealing temperatures while improving the toughness and tear resistance of the film. For example, CN103153618A discloses a polyolefin composite film with a five-layer structure consisting of a surface layer, an intermediate layer, a core layer, another intermediate layer, and a surface layer, wherein the surface layer contains 0-50% by weight of a propylene-α-olefin random copolymer and / or a 1-butene-α-olefin copolymer, and 50-100% by weight of a propylene polymer with a melting point of 120-170℃, achieving characteristics such as low-temperature heat-sealing properties, good heat-sealing strength, and transparency. CN106626654A discloses a polyolefin film material with a low heat-sealing temperature, comprising a five-layer structure consisting of an upper surface layer, two core layers, and a lower surface layer, arranged sequentially. Both the upper and lower surface layers are prepared from the following components: 50-80 parts of a propylene copolymer, 20-40 parts of an olefin-based elastomer, 1-6 parts of an anti-blocking agent, and 1-4 parts of a slip agent. This film material has a low heat-sealing temperature and a wide heat-sealing temperature range, exhibiting better performance than traditional heat-sealing POF (polyolefin heat-shrinkable film) products when used in high-speed automatic sealing packaging machines. However, existing heat-sealing film materials still struggle to simultaneously achieve a low initial sealing temperature and a suitable heat-sealing temperature range, resulting in insufficient heat-sealing performance.

[0005] Therefore, developing materials that can improve the heat-sealing performance of polyolefin films is an urgent problem to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a propylene-based copolymer, its preparation method, and its application. The propylene-based copolymer has a specific design for density, molecular weight, and γ value, enabling the control of material structure and composition. When used in polyolefin film materials, it can reduce the initial sealing temperature, broaden the heat sealing temperature range, and significantly improve the heat sealing performance of polyolefin films containing it.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a propylene-based copolymer, wherein the weight-average molecular weight of the propylene-based copolymer is 2.0 × 10⁻⁶. 4 -40.0×10 4 g / mol, density 0.860-0.890 g / cm³ 3 The γ value of the propylene copolymer is ≥80%, and the formula for calculating the γ value is shown in Formula A:

[0009] γ = 100% × m1 / m0 (Formula A)

[0010] In Formula A, m1 represents the mass of soluble matter in the propylene copolymer measured by temperature gradient cross-chromatography at a first temperature, m0 represents the injection mass of the propylene copolymer for temperature gradient cross-chromatography testing, and the first temperature is ≤40℃.

[0011] The propylene-based copolymer provided by this invention has a specific molecular weight and density, which falls within the range of typical polyolefin elastomer materials. Simultaneously, the propylene-based copolymer has a high γ value. By designing the density, molecular weight, and γ value, the material structure and composition can be controlled, enabling the propylene-based copolymer to be used in polyolefin film materials. This effectively reduces the initial sealing temperature, broadens the heat-sealing temperature range, and improves heat-sealing performance.

[0012] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0013] In this invention, the weight-average molecular weight (M) of the propylene copolymer is... w ) is 2.0 × 10 4 -40.0×10 4 g / mol, for example, could be 3.0 × 10⁻⁶ g / mol. 4 g / mol, 5.0×10 4 g / mol, 8.0×10 4 g / mol, 10.0×10 4 g / mol, 12.0×10 4 g / mol, 15.0×10 4 g / mol, 18.0×10 4 g / mol, 20.0×10 4 g / mol, 22.0×10 4 g / mol, 25.0×10 4 g / mol, 28.0×10 4 g / mol, 30.0×10 4 g / mol, 32.0×10 4 g / mol, 35.0×10 4 g / mol or 38.0 × 10 4 g / mol, and specific point values ​​between the above-mentioned point values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific point values ​​included in the range, but preferably 3.0 × 10 g / mol. 4 -30.0×10 4 g / mol, further optimized to 3.0 × 10 g / mol. 4 -35.0×10 4 g / mol.

[0014] Preferably, the molecular weight distribution of the propylene copolymer is 2.0-4.0, for example, it can be 2.2, 2.5, 2.8, 3.0, 3.2, 3.5 or 3.8, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, and 2.5-3.5 is further preferred.

[0015] For example, the weight-average molecular weight (M) of the present invention w Number-average molecular weight (M) n The molecular weight distribution was obtained by gel permeation chromatography (GPC), using polystyrene as a standard; the molecular weight distribution was M. w / M n .

[0016] In this invention, the density of the propylene-based copolymer is 0.860-0.890 g / cm³. 3 For example, it could be 0.862 g / cm³. 3 0.865g / cm 3 0.868 g / cm 3 0.870 g / cm 3 0.872 g / cm 3 0.875g / cm 3 0.878 g / cm 3 0.880 g / cm 3 0.882 g / cm 3 0.885g / cm 3 Or 0.888g / cm 3 And the specific point values ​​between the above-mentioned point values, due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific point values ​​included in the range, preferably 0.860-0.885 g / cm³. 3 Further optimization was performed using 0.860-0.880 g / cm³. 3 .

[0017] For example, the density of the propylene copolymer is determined by methods in ASTM D792-2021 or ASTM D792-13.

[0018] In this invention, the γ value of the propylene copolymer is ≥80%, for example, it can be 82%, 85%, 88%, 90%, 92%, 95%, 98%, 99% or 100%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0019] In this invention, γ = 100% × m1 / m0, where m1 represents the mass of soluble matter in the propylene copolymer measured by temperature gradient cross-chromatography (TGIC) at a first temperature (≤40℃), and m0 represents the injection mass of the propylene copolymer for temperature gradient cross-chromatography testing.

[0020] It should be noted that the TGIC of the present invention is a temperature gradient interaction high-temperature chromatography, which utilizes the interaction between polyolefin chains and graphite columns, as well as the combined effects of adsorption-desorption and crystallization properties, to achieve the separation of different components of polyolefins under certain solvent flow rates and temperature changes.

[0021] Preferably, the first temperature is ≤40℃, for example, it can be 0℃, 5℃, 10℃, 15℃, 20℃, 25℃, 30℃, 35℃ or 38℃, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0022] Preferably, the propylene copolymer (sample to be tested) is subjected to temperature gradient cross-chromatographic testing, and the sample to be tested is extracted in the organic solvent used for testing, and the extraction temperature is a first temperature (≤40℃).

[0023] Preferably, the extraction time is 0.1-6h, for example, it can be 0.2h, 0.5h, 0.8h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h or 5.5h, as well as specific point values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific point values ​​included in the range.

[0024] Preferably, the organic solvent used in the temperature gradient cross-chromatographic test is trichlorobenzene.

[0025] Preferably, the trichlorobenzene includes any one or a combination of at least two of 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, and 1,3,5-trichlorobenzene.

[0026] Preferably, the melt index of the propylene copolymer at 230°C and a load of 2.16 kg is 1-80 g / 10 min, for example, it can be 2 g / 10 min, 5 g / 10 min, 8 g / 10 min, 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, 35 g / 10 min, 40 g / 10 min, 45 g / 10 min, 50 g / 10 min, 55 g / 10 min, 60 g / 10 min, 65 g / 10 min, 70 g / 10 min or 75 g / 10 min, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0027] For example, the melt index (MI) of the propylene copolymer is obtained by the method in ASTM D1238-13 (230°C, 2.16 kg).

[0028] Preferably, the melting temperature (T) of the propylene-based copolymer is... m The temperature range is 80-130℃, for example, it can be 82℃, 85℃, 88℃, 90℃, 92℃, 95℃, 98℃, 100℃, 102℃, 105℃, 108℃, 110℃, 112℃, 115℃, 118℃, 120℃, 122℃, 125℃ or 128℃, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range, and 95-120℃ is further preferred.

[0029] For example, the melting temperature (T) of the propylene-based copolymer m The temperature was obtained by differential scanning calorimetry (DSC). The test procedure was as follows: First, the copolymer was heated to 200℃ and held for 5 minutes to eliminate thermal history. Then, it was cooled to -60℃ and then heated again to 200℃. The heating and cooling rates were controlled at 10℃ / min throughout the test, and the measurement results during the second heating process were calibrated as the melting temperature.

[0030] Preferably, the propylene-based copolymer is a copolymer of propylene and a first olefin, wherein the first olefin includes any one or a combination of at least two of ethylene and C4-C20 α-olefins.

[0031] The C4-C20 α-olefins can be C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, or C20 α-olefins.

[0032] Preferably, the first olefin comprises any one or a combination of at least two of ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, and 1-dodecene; more preferably, ethylene, any one or a combination of at least two of 1-hexene and 1-octene; and even more preferably, ethylene.

[0033] Preferably, the mass percentage of the structural unit based on the first olefin in the propylene copolymer is 5-20%, for example, it can be 5.5%, 6%, 7%, 8%, 9%, 9.5%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 18.5% or 19%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0034] The majority of the constituent units in the propylene-based copolymer are derived from propylene. Preferably, the molar percentage of propylene-based structural units in the propylene-based copolymer is 50-97%, for example, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range. Preferably, it is 60-90%, more preferably 70-90%, and even more preferably 80-90%.

[0035] The molar percentage of the structural unit based on the first olefin (comonomer, ethylene and / or C4-C20 α-olefin) in the propylene copolymer is 3-50%, for example, it can be 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45% or 48%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range. Preferably, it is 10-40%, more preferably 10-30%, and more preferably 10-20%.

[0036] In a second aspect, the present invention provides a method for preparing a propylene-based copolymer as described in the first aspect, the method comprising: polymerizing propylene and a first olefin under the catalysis of a catalyst to obtain the propylene-based copolymer.

[0037] Preferably, the catalyst comprises a main catalyst, which comprises at least one of a transition metal compound with the structure shown in Formula I and a metallocene compound with the structure shown in Formula II:

[0038]

[0039] In Equation I, R1-R16 Each is independently selected from any one of hydrogen, C1-C30 straight-chain or branched alkyl, C1-C30 alkoxy, C3-C30 cycloalkyl, C3-C30 cycloalkyloxy, C6-C30 aryl, C6-C30 aryloxy, and C3-C30 heteroaryl.

[0040] In Formula I, M1 is selected from any metal in Group IVB.

[0041] In Formula I, X1 and X2 are each independently selected from any one of halogen, C1-C10 straight-chain or branched alkyl, C1-C10 alkoxy, C3-C10 cycloalkyl, C3-C10 cycloalkyloxy, C6-C14 aryl, C6-C14 aryloxy, and C7-C30 arylalkyl.

[0042] In Formula I, L is selected from any one of C1-C10 straight-chain or branched alkylene groups and C3-C10 cycloalkylene groups.

[0043]

[0044] In Equation II, R 21 R 25 R 29 R 30 Each is independently selected from any one of hydrogen, substituted or unsubstituted C1-C30 straight-chain or branched alkyl groups, or substituted or unsubstituted C3-C30 cycloalkyl groups;

[0045] In Equation II, R 22 R 23 R 24 R 26 R 27 R 28 Each is independently selected from any one of hydrogen, substituted or unsubstituted C1-C30 straight-chain or branched alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 alkenyl, and substituted or unsubstituted C1-C30 alkoxy.

[0046] The R 22 R 23 R 24 R 26 R 27 R 28 Any two adjacent groups in the group may be connected by chemical bonds to form a ring or not;

[0047] In Formula II, Y is selected from any one of carbon, silicon, or germanium;

[0048] In Formula II, Q1 and Q2 are each independently selected from any one of substituted or unsubstituted C1-C30 straight-chain or branched alkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C3-C30 heteroaryl groups;

[0049] In Formula II, M2 is selected from any one of the group IVB metals;

[0050] In Formula II, X3 and X4 are each independently selected from any one of halogen, amino, substituted or unsubstituted C1-C30 straight-chain or branched alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 alkylamino, substituted or unsubstituted C6-C30 arylamino, and substituted or unsubstituted C7-C30 arylalkyl.

[0051] In Formula II, each of the substituents is independently selected from at least one of halogen, amino, C1-C10 straight-chain or branched alkyl, C3-C10 cycloalkyl, silyl, C6-C30 aryl, and C3-C30 heteroaryl.

[0052] In this invention, the "substituted or unsubstituted" group can replace one substituent or multiple substituents. When there are multiple substituents (at least two), they can be the same or different substituents. The same expression used below has the same meaning. Unless otherwise specified, the selection range of substituents in the metallocene compounds represented by Formula II is as shown above and will not be repeated.

[0053] Catalytic systems play a crucial role in polymer preparation. The propylene-based copolymers can be prepared using catalyst systems comprising transition metal compounds with the structure shown in Formula I and metallocene compounds (also transition metal compounds) with the structure shown in Formula II. In this invention, by using a catalytic system comprising a main catalyst having a specific structure (at least one of a transition metal compound with the structure shown in Formula I and a metallocene compound with the structure shown in Formula II), suitable amounts of comonomers (a first olefin, ethylene, and / or C4-C20 α-olefins) can be introduced, resulting in a propylene-based copolymer with a specific molecular weight M. w Density, molecular weight distribution, and γ value.

[0054] In this invention, the C1-C30 straight-chain or branched alkyl groups can be straight-chain or branched alkyl groups of C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C25, C26, C28, etc., preferably C1-C20 straight-chain or branched alkyl groups, and more preferably C1-C10 straight-chain or branched alkyl groups. Exemplarily, they include but are not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, 2-methylbutyl, n-pentyl, isopentyl, neopentyl, n-hexyl, neohexyl, 2-ethylhexyl, n-octyl, n-heptyl, n-nonyl, n-decyl, etc.

[0055] In this invention, the C1-C30 alkoxy groups can all be straight-chain or branched alkoxy groups of C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C25, C26, C28, etc., preferably C1-C20 alkoxy groups, and more preferably C1-C10 alkoxy groups. A specific example is a monovalent group formed by connecting the above-mentioned straight-chain or branched alkyl groups to O.

[0056] In this invention, the C3-C30 cycloalkyl groups can all be cycloalkyl groups of C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C25, C26, or C28, including monocycloalkyl or polycycloalkyl groups, preferably C3-C20 cycloalkyl groups, and more preferably C3-C10 cycloalkyl groups. Exemplary examples include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantyl, etc.

[0057] In this invention, the C3-C30 cycloalkyloxy groups can all be cycloalkyloxy groups of C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C25, C26 or C28, etc., preferably C3-C20 cycloalkyloxy groups, more preferably C3-C10 cycloalkyloxy groups, and a specific example is a monovalent group formed by attaching the above-mentioned cycloalkyl group to O.

[0058] In this invention, the C6-C30 aryl groups can all be aryl groups of C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, or C28, etc., and are further preferably C6-C20 aryl groups, including monocyclic aryl groups and fused-ring aryl groups, and exemplary of including but not limited to: phenyl, biphenyl, terphenyl, tetraphenyl, naphthyl, anthracene, phenanthryl, binatyl, benzocyclopentenyl, benzocyclopentadienyl, etc.

[0059] In this invention, the C6-C30 aryloxy groups can all be aryloxy groups of C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, etc., and are further preferred to be C6-C20 aryloxy groups. A specific example is a monovalent group formed by the above-mentioned aryl group and O.

[0060] In this invention, the C3-C30 heteroaryl groups can all be heteroaryl groups of C3, C4, C5, C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, or C28, preferably C3-C20 heteroaryl groups, wherein the heteroatoms can be N, O, S, etc.; including monocyclic heteroaryl or fused-ring heteroaryl groups, including but not limited to: pyridinyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, furanyl, thiopheneyl, pyrroleyl, quinolinyl, isoquinolinyl, quinoxalinyl, quinazolinyl, benzofuranyl, benzothiopheneyl, indolyl, dibenzofuranyl, dibenzothiopheneyl, carbazoleyl, N-phenylcarbazoleyl, etc.

[0061] In this invention, the halogens include fluorine, chlorine, bromine, and iodine.

[0062] In this invention, the C1-C10 straight-chain or branched alkyl groups can be straight-chain or branched alkyl groups of C1, C2, C3, C4, C5, C6, C7, C8, C9, and C10, and exemplary include but are not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, 2-methylbutyl, n-pentyl, isopentyl, neopentyl, n-hexyl, neohexyl, 2-ethylhexyl, n-octyl, n-heptyl, n-nonyl, n-decyl, etc.

[0063] The C1-C10 straight-chain or branched alkylene groups can be straight-chain or branched alkylene groups of C1, C2, C3, C4, C5, C6, C7, C8, C9, and C10. A specific example is a divalent group formed by the loss of one H atom by the above straight-chain or branched alkyl group.

[0064] The C1-C10 alkoxy groups can all be straight-chain or branched alkoxy groups of C1, C2, C3, C4, C5, C6, C7, C8, C9, and C10. A specific example is a monovalent group formed by connecting the above straight-chain or branched alkyl groups to O.

[0065] In this invention, the C3-C10 cycloalkyl groups can all be C3, C4, C5, C6, C7, C8, C9, or C10 cycloalkyl groups, including monocycloalkyl or polycycloalkyl groups, and exemplary of, but not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantyl, etc.

[0066] The C3-C10 cycloalkyl group can be a C3, C4, C5, C6, C7, C8, C9, or C10 cycloalkyl group. A specific example is a divalent group formed by the above cycloalkyl group losing one H.

[0067] The C3-C10 cycloalkyloxy group can be a cycloalkyloxy group of C3, C4, C5, C6, C7, C8, C9, or C10. A specific example is a monovalent group formed by attaching the above-mentioned cycloalkyl group to O.

[0068] In this invention, the C6-C14 aryl groups can all be aryl groups of C6, C9, C10, C12, C13, C14, etc., and exemplary include but are not limited to: phenyl, biphenyl, naphthyl, anthracene, phenanthrene, etc.

[0069] The C6-C14 aryloxy groups can all be aryloxy groups of C6, C9, C10, C12, C13, C14, etc., and a specific example is a monovalent group formed by attaching the above-mentioned aryl group to O.

[0070] The C7-C30 aryl alkyl groups can all be aryl alkyl groups of C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C25, C26, C28, etc., preferably C7-C20 aryl alkyl groups, more preferably C7-C15 aryl alkyl groups. A specific example is a monovalent group formed by attaching the above-mentioned aryl group to a straight-chain or branched alkyl group, a typical example being benzyl (phenylmethyl).

[0071] In this invention, the C2-C30 alkenyl groups can all be straight-chain or branched alkenyl groups of C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C25, C26, C28, etc., containing at least one C=C, and exemplary including but not limited to: vinyl, propenyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, butadienyl, pentadienyl, etc.

[0072] In this invention, the C1-C30 alkylamino groups can all be alkylamino groups of C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C25, C26, C28, etc., and are monovalent groups obtained by substituting at least one hydrogen in -NH2 with the above-mentioned straight-chain or branched alkyl groups.

[0073] In this invention, the C6-C30 arylamino groups can all be arylamino groups of C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, etc., and are monovalent groups obtained by substituting at least one hydrogen in -NH2 with the above-mentioned aryl group.

[0074] Preferably, in formula I, R1-R 16 Each is independently selected from hydrogen, C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) straight-chain or branched alkyl groups, C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) alkoxy groups, C3-C10 (e.g., C4, C5, C6, C7, C8, C9, etc.) cycloalkyl groups, and C6-C20 (e.g., C6, C9, C10, C1... 2. Any one of the following: aryl (C14, C16, C18, etc.), aryloxy (C6-C20, such as C6, C9, C10, C12, C14, C16, C18, etc.), heteroaryl (C3-C20, such as C4, C5, C6, C9, C10, C12, C14, C16, C18, etc.), and more preferably any one of hydrogen, C1-C6 straight-chain or branched alkyl, phenyl, carbazole.

[0075] Furthermore, the transition metal compound with the structure shown in Formula I preferably has the structure shown in Formula I-1:

[0076]

[0077] Preferably, in Formula I and Formula I-1, L is selected from any one of C2-C8 (e.g., C3, C4, C5, C6, C7, etc.) straight-chain or branched alkylene groups and C4-C8 (e.g., C5, C6, C7, etc.) cycloalkylene groups. More preferably... Any one of them, -* represents the linking site of the group; m' is selected from an integer ≥1, such as 1, 2, 3, etc., more preferably 1 or 2.

[0078] Furthermore, the transition metal compound with the structure shown in Formula I preferably has the structure shown in Formula I-2:

[0079]

[0080] Preferably, in formulas I, I-1, and I-2, R1, R3, R6, R7, and R... 10 R 11 R 14 R 16 Each is independently selected from hydrogen, C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) straight-chain or branched alkyl groups, C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) alkoxy groups, C3-C10 (e.g., C4, C5, C6, C7, C8, C9, etc.) cycloalkyl groups, and C6-C20 (e.g., C6, C9, C10, C12, C14, C16, C18, etc.) aryl groups. Any one of C6-C20 (e.g., C6, C9, C10, C12, C14, C16, C18, etc.) aryloxy groups, or C3-C20 (e.g., C4, C5, C6, C9, C10, C12, C14, C16, C18, etc.) heteroaryl groups, further preferably any one of hydrogen, C1-C6 straight-chain or branched alkyl groups, phenyl, or carbazole group, more preferably hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, or carbazole group.

[0081] Preferably, X1 and X2 are each independently selected from any one of halogen (fluorine, chlorine, bromine, iodine), C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) straight-chain or branched alkyl, phenyl, benzyl, more preferably chlorine, methyl, benzyl (Bn).

[0082] Preferably, the transition metal compound with the structure shown in Formula I includes any one or a combination of at least two of the following compounds:

[0083]

[0084]

[0085] Wherein, Bn represents benzyl and Cz represents carbazolyl. Preferably, M1 is selected from any one of titanium (Ti), zirconium (Zr), or hafnium (Hf).

[0086] Preferably, in formula II, the R 21 R 25 R 29 R 30Each is independently selected from hydrogen, substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) straight-chain or branched alkyl groups, substituted or unsubstituted C3-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) cycloalkyl groups, more preferably hydrogen and C1-C6 straight-chain or branched alkyl groups.

[0087] Preferably, in formula II, R 22 R 23 R 24 R 26 R 27 R 28 Each of the following is independently selected from hydrogen, substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) straight-chain or branched alkyl, substituted or unsubstituted C6-C20 (e.g., C6, C9, C10, C12, C14, C16, C18, etc.) aryl, substituted or unsubstituted C2-C10 (e.g., C3, C4, C5, C6, C7, C8, C9, etc.) alkenyl, substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) alkoxy, and more preferably hydrogen, C1-C6 straight-chain or branched alkyl, phenyl, naphthyl.

[0088] In Formula II, R 22 R 23 R 24 R 26 R 27 R 28 Any two adjacent groups in the group may be connected by a chemical bond to form a ring or not; where "R" 22 R 23 R 24 R 26 R 27 R 28 "No two adjacent groups are connected" means that the aforementioned group is only connected to the C atom through a single bond; "R" 22 R 23 R 24 R 26 R 27 R 28 "Any two adjacent groups in the above-mentioned group are connected by chemical bonds to form a ring" means that any two adjacent groups in the above-mentioned group are connected by chemical bonds to form a fused ring structure.

[0089] Preferably, in formula II, R 22 R 23 R 24 R 26R 27 R 28 Any two adjacent groups are chemically bonded to form a ring Cy or not, wherein the ring Cy is selected from any one of substituted or unsubstituted C3-C20 (e.g., C4, C5, C6, C9, C10, C12, C14, C16, C18, etc.) alicyclic rings or substituted or unsubstituted C6-C20 (e.g., C6, C9, C10, C12, C14, C16, C18, etc.) aromatic rings, and is further preferred. The dashed lines represent the fused ring bonds of the Cy ring.

[0090] Preferably, in Formula II, Q1 and Q2 are each independently selected from any one of substituted or unsubstituted C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) straight-chain or branched alkyl groups, substituted or unsubstituted C6-C20 (e.g., C6, C9, C10, C12, C14, C16, C18, etc.) aryl groups, substituted or unsubstituted C3-C20 (e.g., C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17 or C18, etc.) heteroaryl groups, and more preferably any one of C1-C6 straight-chain or branched alkyl groups and phenyl groups.

[0091] Preferably, in Formula II, M2 is selected from any one of titanium (Ti), zirconium (Zr), or hafnium (Hf).

[0092] Preferably, in Formula II, X3 and X4 are each independently selected from any one of halogens (fluorine, chlorine, bromine, iodine), C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) straight-chain or branched alkyl groups, phenyl, and benzyl, more preferably chlorine or C1-C6 straight-chain or branched alkyl groups.

[0093] Preferably, the metallocene compound with the structure shown in Formula II comprises any one or a combination of at least two of the following compounds:

[0094]

[0095]

[0096] In this context, Me represents methyl and Ph represents phenyl.

[0097] Preferably, the catalyst further includes a co-catalyst, which includes any one or a combination of at least two of the compounds with the structure shown in Formula III, Formula IV, Formula V, and Formula VI.

[0098]

[0099] In Equation III, R 31 R 31 R 33 Each is independently selected from any one of hydrogen, halogen, C1-C30 hydrocarbon group, or halogen-substituted C1-C30 hydrocarbon group.

[0100] In Equation III, n is an integer ≥ 2.

[0101]

[0102] In Formula IV, Z represents aluminum or boron.

[0103] In equation IV, R 41 R 41 R 43 Each is independently selected from any one of halogen, C1-C30 hydrocarbon group, or halogen-substituted C1-C30 hydrocarbon group.

[0104] [LH] + [Z(A)4] - Formula V;

[0105] [L] + [Z(A)4] - Formula VI;

[0106] Where L represents a neutral Lewis base or a cationic Lewis base.

[0107] Z is selected from any of the elements in group 13.

[0108] A is independently selected from any one of substituted or unsubstituted C1-C30 hydrocarbon groups and substituted or unsubstituted C1-C30 hydrocarbon oxy groups; the substituents in A are independently selected from at least one of halogen, C1-C30 hydrocarbon oxy group, and C1-C30 hydrocarbon silyl group.

[0109] In this invention, the C1-C30 hydrocarbon groups can all be hydrocarbon groups of C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C25, C26, C28, etc. Specific examples include: C1-C30 (e.g., C2...). Straight-chain or branched alkyl groups (C3, C4, C5, C6, C8, C10, C12, C14, C15, C16, C18, C20, C22, C24, C25, C26, C28, etc.) and C3-C30 (e.g., C4, C5, C6, C8, C10, C12, C14, C15, C16, C18, C20, C22, C24, etc.). Cycloalkyl groups (C25, C26, C28, etc.), aryl groups (C6-C30, e.g., C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26, or C28, etc.), and aryl groups (C7-C30, e.g., C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C28, C25, C26, C28, etc.) 20, C22, C24, C25, C26, C28, etc.) arylalkyl, C7-C30 (e.g., C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C25, C26, C28, etc.) alkylaryl, further specific examples are as described above, and will not be repeated here.

[0110] In this invention, the C1-C30 alkyl group can be an alkyl group of C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C25, C26, C28, etc., and a specific example is a monovalent group formed by attaching the aforementioned hydrocarbon group to an O atom.

[0111] In this invention, the C1-C30 hydrocarbon silane can be a hydrocarbon silane of C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C25, C26, C28, etc., and is a monovalent group obtained by substituting at least one hydrogen in -SiH3 with the aforementioned hydrocarbon group.

[0112] Preferably, the compound with the structure shown in Formula III can be a compound based on alkylaluminoxane, wherein the repeating units are combined into a linear, cyclic or network structure, and specific examples may include any one or a combination of at least two of methylaluminoxane (MAO), ethylaluminoxane, isobutylaluminoxane, and tert-butylaluminoxane.

[0113] Preferably, the compound with the structure shown in Formula IV is any one or a combination of at least two of trialkylaluminum and trialkylboron. Specific examples include, but are not limited to, any one or a combination of at least two of trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylaluminum chloride, triisopropylaluminum, trisec-butylaluminum, tricyclopentylaluminum, tripentylaluminum, triisopentylaluminum, trihexylaluminum, trioctylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri-p-tolylaluminum, dimethylmethoxyaluminum, dimethylethoxyaluminum, trimethylboron, triethylboron, triisobutylboron, tripropylboron, and tributylboron. More preferably, any one or a combination of at least two of trimethylaluminum, triethylaluminum, and triisobutylaluminum is selected.

[0114] Preferably, the molar ratio of aluminum in the trialkylaluminum to the transition metal in the main catalyst is (1-2000):1, for example, it can be 2:1, 5:1, 8:1, 10:1, 20:1, 50:1, 80:1, 100:1, 200:1, 300:1, 500:1, 600:1, 800:1, 1000:1, 1200:1, 1400:1, 1500:1, 1600:1, 1800:1 or 1900:1, etc., and more preferably (1-1000):1.

[0115] Preferably, the compounds with the structure shown in Formula V and the compounds with the structure shown in Formula VI include borate compounds, specifically including any one or a combination of at least two of the following: trisubstituted ammonium salt borates, dialkyl ammonium salt borates, and trisubstituted phosphonium salt borates.

[0116] Preferably, the trisubstituted ammonium borates include trimethylammonium tetraphenylborate, methyl di(octadecyl)ammonium tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, methyltetradecyl octadecylammonium tetraphenylborate, N,N-dimethylphenylammonium tetraphenylborate, N,N-diethylphenylammonium tetraphenylborate, N,N-dimethyl(2,4,6-trimethylphenylammonium)tetraphenylborate, trimethylammonium tetra(pentafluorophenyl)borate, methyl di(tetradecyl)ammonium tetra(pentafluorophenyl)borate, methyl di(octadecyl)ammonium tetra(pentafluorophenyl)borate, triethylammonium tetra(pentafluorophenyl)borate, tripropylammonium tetra(pentafluorophenyl)borate, tri(n-butyl)ammonium tetra(pentafluorophenyl)borate, trisec-butylammonium tetra(pentafluorophenyl)borate, N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate, and N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate. (Fluorophenyl)borate, N,N-diethylphenylammonium tetra(pentafluorophenyl)borate, N,N-dimethyl(2,4,6-trimethylphenylammonium)tetra(pentafluorophenyl)borate, trimethylammonium tetra(2,3,4,6-tetrafluorophenyl)borate, triethylammonium tetra(2,3,4,6-tetrafluorophenyl)borate, tripropylammonium tetra(2,3,4,6-tetrafluorophenyl)borate, tri(n-butylammonium tetra(2,3,4,6-tetrafluorophenyl)borate The first one or a combination of at least two of the following: (fluorophenyl)borate, dimethyl(tert-butyl)ammonium tetra(2,3,4,6-tetrafluorophenyl)borate, N,N-dimethylphenylammonium tetra(2,3,4,6-tetrafluorophenyl)borate, N,N-diethylphenylammonium tetra(2,3,4,6-tetrafluorophenyl)borate, and N,N-dimethyl-(2,4,6-trimethylphenylammonium)tetra(2,3,4,6-tetrafluorophenyl)borate.

[0117] Preferably, the dialkylammonium salt type borate includes any one or a combination of at least two of di(octadecyl)ammonium tetra(pentafluorophenyl)borate, di(tetradecyl)ammonium tetra(pentafluorophenyl)borate, and di(cyclohexyl)ammonium tetra(pentafluorophenyl)borate.

[0118] Preferably, the trisubstituted phosphonium salt type borate includes any one or a combination of at least two of triphenylphosphonium tetra(pentafluorophenyl)borate, methyl di(octadecyl)phosphonium tetra(pentafluorophenyl)borate, and tri(2,6-dimethylphenyl)phosphonium tetra(pentafluorophenyl)borate.

[0119] Preferably, the molar ratio of boron in the borate compound to the transition metal in the main catalyst is (1-10):1, for example, it can be 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1, etc.

[0120] In addition, during the polymerization reaction, an organoaluminum compound is further injected into the reaction apparatus to remove moisture, and the polymerization reaction can be carried out in the presence of the organoaluminum compound. Specific examples of the organoaluminum compound may include any one or a combination of at least two of trialkylaluminum, dialkylaluminum halide, alkylaluminum dihalide, dialkylaluminum hydride, and alkylsesquihalide, exemplary including but not limited to: Al(C2H5)3, Al(C2H5)2H, Al(C3H7)3, Al(C3H7)2H, Al(i-C4H9)2H, Al(C8H5)2H, etc. 17 3. Al(C) 12 H 25 3. Al(C2H5)(C 12 H 25 )2、Al(i-C4H9)(C 12 H 25 2. Any one or at least two combinations of Al(i-C4H9)2H, Al(i-C4H9)3, (C2H5)2AlCl, (i-C3H9)2AlCl, and (C2H5)3Al2Cl3.

[0121] The organoaluminum compound can be continuously injected into the reaction apparatus, and in order to properly remove impurities such as water and oxygen, the organoaluminum compound can be injected into the reaction medium at a ratio of about 0.1-10 mol / 1kg (e.g., 0.5 mol / 1kg, 1 mol / 1kg, 2 mol / 1kg, 3 mol / 1kg, 4 mol / 1kg, 5 mol / 1kg, 6 mol / 1kg, 7 mol / 1kg, 8 mol / 1kg, 9 mol / 1kg, etc.).

[0122] In this invention, the apparatus used for the polymerization reaction is a continuous polymerization reactor with different volumes and different reactor types.

[0123] Preferably, the apparatus for the polymerization reaction includes a batch reactor or a circulating loop reactor.

[0124] Preferably, the batch reactor is a single reactor or a number of reactors (e.g., 2, 3, 4, 5, 6, etc.) connected in series, and the length-to-diameter ratio of the reactor is (5-10):1, for example, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, etc.

[0125] In a preferred embodiment, a batch reactor is used as the polymerization apparatus, which can be a cylindrical or tank-shaped container, either unstirred or stirred. By adjusting the length-to-diameter ratio of the reactor, the material entering the reactor exhibits temperature and concentration distributions, further enabling the adjustment of the polymer composition and structure generated in different temperature regions of the microscopic area. Ultimately, the propylene-based copolymer with specific density, molecular weight, and γ value can be obtained.

[0126] Preferably, the circulation ratio of the circulating loop reactor is 1-1000, for example, it can be 2, 5, 8, 10, 20, 50, 80, 100, 200, 300, 400, 500, 600, 700, 800 or 900, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0127] In another preferred embodiment, a circulating loop reactor (e.g., a loop reactor) is used as the apparatus for the polymerization reaction. By adjusting the ratio of the circulation volume of the reactor circulation pump per unit time to the reactor volume, i.e., the circulation ratio, the composition and structure of the polymer generated in different temperature regions of the microscopic area can be further adjusted, and the propylene-based copolymer with specific density, molecular weight and γ value can be obtained.

[0128] Preferably, the polymerization reaction is carried out in the presence of a solvent, i.e., solution polymerization is employed.

[0129] Preferably, the solvent includes any one or a combination of at least two of the following: alkane solvents, haloalkane solvents, cycloalkane solvents, and aromatic solvents; more preferably, it includes any one or a combination of at least two of the following: n-hexane, cyclohexane, heptane, toluene, xylene, and isoalkanes.

[0130] Preferably, the polymerization reaction is carried out in the presence or absence of a molecular weight adjuster; the molecular weight adjuster includes hydrogen gas, and more preferably the hydrogen injection rate is 0-100 g / min, for example 1 g / min, 5 g / min, 10 g / min, 20 g / min, 30 g / min, 40 g / min, 50 g / min, 60 g / min, 70 g / min, 80 g / min or 90 g / min, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0131] Preferably, the polymerization reaction temperature is 50-200℃, for example, it can be 60℃, 70℃, 80℃, 90℃, 100℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃ or 190℃, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, but 80-180℃ is further preferred.

[0132] Preferably, the pressure of the polymerization reaction is 0.1-10 MPa, for example, it can be 0.2 MPa, 0.5 MPa, 0.8 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.5 MPa, 5 MPa, 5.5 MPa, 6 MPa, 7 MPa, 8 MPa or 9 MPa, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, and 1-5 MPa is further preferred.

[0133] Preferably, the polymerization reaction further includes a post-processing step, which includes quenching and / or devolatilization.

[0134] Preferably, the devolatilization method includes flash devolatilization.

[0135] Thirdly, the present invention provides an application of the propylene-based copolymer as described in the first aspect in polyolefin membrane materials.

[0136] Fourthly, the present invention provides a polyolefin membrane comprising a propylene-based copolymer as described in the first aspect.

[0137] Preferably, the polyolefin film is a polypropylene film, and more preferably a cast polypropylene film (CPP cast film).

[0138] Preferably, the polyolefin film (preferably a polypropylene film) includes a heat-sealing layer, the heat-sealing layer comprising a propylene-based copolymer as described in the first aspect.

[0139] It should be noted that the polyolefin film (preferably a polypropylene film) can have a single-layer structure, in which case the film material is a heat-sealing film material (heat-sealing layer, containing the propylene-based copolymer provided by the present invention); or it can have a multi-layer structure, such as 2 layers, 3 layers, 4 layers, 5 layers, 6 layers, etc. Except for the heat-sealing layer, the present invention does not limit the materials of other layers in the multi-layer structure, and all materials known in the art that can be used for polyolefin films are applicable to the present invention.

[0140] Preferably, the mass percentage of the propylene-based copolymer in the heat-sealing layer is 1-50%, for example, it can be 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 35%, 40%, or 45%, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, but 5-30% is further preferred.

[0141] Preferably, the heat-sealing layer further includes a polyolefin base material, such as a polypropylene base material, which may be homopolymer polypropylene and / or copolymer polypropylene.

[0142] As a preferred embodiment of the present invention, the propylene-based copolymer is used as a modifier in the heat-sealing layer of CPP cast film. Due to its improved γ value, it exhibits excellent properties of reducing the initial sealing temperature and widening the heat-sealing temperature range. Preferably, the initial sealing temperature of the heat-sealing layer is as low as 113°C, while the heat-sealing temperature is 113-118°C (e.g., 114°C, 115°C, 116°C, 117°C), thus widening the heat-sealing temperature range and improving the heat-sealing performance of the polyolefin film.

[0143] Compared with the prior art, the present invention has the following beneficial effects:

[0144] The propylene-based copolymer provided by this invention achieves control over the material structure and composition through the design of specific molecular weight, density, and γ value. When used in polyolefin film materials, the propylene-based copolymer effectively reduces the initial sealing temperature, widens the heat-sealing temperature range, and significantly improves the heat-sealing performance of polyolefin films containing it. Detailed Implementation

[0145] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0146] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not limited to those elements and may also include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0147] "Optional" or "any one" means that the matter or event described thereafter may or may not occur, and the description includes both the possibility that the event may occur and the possibility that the event may not occur.

[0148] In one specific embodiment, the transition metal compound with the structure shown in Formula I can be prepared by synthetic methods disclosed in the prior art, such as US20040014950A1, CN116554378A, CN114230702B, CN116212960A and the literature “Stereospecific Octahedral Group 4Bis(phenolate)EtherComplexes for Olefin Polymerization”, J.Am.Chem.Soc.2010, 132, 5566-5567.

[0149] In one specific embodiment, the metallocene compound with the structure shown in Formula II can be prepared by synthetic methods disclosed in the prior art, such as US6057408A, CN117777183A, and the literature “Highly Regiospecific Zirconocene Catalysts for the Isospecific Polymerization of Propene”, J.Am.Chem.Soc.1998, 120, 2308-2321 and “The Influence of Aromatic Substituents on the Polymerization Behavior of Bridged Zirconocene Catalysts”, Organometallics1994, 13, 954-963.

[0150] In the following specific embodiments of the present invention, the main testing methods for the polymer are as follows:

[0151] (1) Molecular weight (weight-average molecular weight M) w Number average molecular weight M n ), molecular weight distribution (PDI, M) w / M n The results were obtained by gel permeation chromatography (GPC); column: PL Olexis, solvent: trichlorobenzene (TCB), flow rate: 1.0 mL / min, sample concentration: 1.0 mg / mL, injection volume: 200 μL, column temperature: 160 °C, detector: Agilent high-temperature RI detector, standard: polystyrene (calibrated using cubic function).

[0152] (2) Density: Tested by the method in ASTM D792-2021.

[0153] (3) Melt flow index: The melt flow index was obtained by the method in ASTM D1238-13 (230℃, 2.16kg load).

[0154] (4) Melting temperature (T) m The melting temperature was obtained using a differential scanning calorimeter (DSC 6000) manufactured by PerkinElmer. Specifically, the temperature was raised to 200°C, held at that temperature for 1 minute, then lowered to -100°C, and then raised again to obtain the top of the DSC curve as the melting point. The rate of temperature increase and decrease was 10°C / min, and the melting temperature was obtained during the second temperature increase.

[0155] (5) γ value: The polymer to be tested was injected into a temperature gradient cross-chromatograph (TGIC) for testing. The solvent used for testing was trichlorobenzene. The sample was extracted in 1,2,4-trichlorobenzene. The initial extraction temperature was 0℃, the heating rate was 1.0℃ / min, and the temperature was increased to 40℃ for a total extraction time of 40min. The mass of soluble matter tested by TGIC was recorded as m1; the mass of the sample injected was m0, and γ = 100% × m1 / m0.

[0156] (6) Ethylene insertion rate: determined by nuclear magnetic resonance (NMR) technology. First, the propylene copolymer sample needs to be dissolved in deuterated tetrachloroethane solvent. The frequency corresponding to the magnetic field strength of the instrument is adjusted to between 300-600MHz. The characteristic proton peaks corresponding to the ethylene and propylene units are obtained by testing and the integral area is calculated. For specific methods, please refer to the literature "NMR Chemical Shifts of Trace Impurities: Common Laboratory Solvents, Organics, and Gases in Deuterated Solvents Relevant to the Organometallic Chemist", Organometallics, 2010, 29(9), 2176–2179 and "NMR Chemical Shifts of Common Laboratory Solvents as Trace Impurities", J.Org.Chem., 1997, 62(21), 7512–7515.

[0157] Example 1

[0158] A propylene-based copolymer, specifically a propylene-ethylene copolymer, is prepared by means of:

[0159] Polymerization experiments were conducted using a small-scale continuous polymerization reactor. The polymerization reaction was solution polymerization, and the reaction unit was a single-reactor polymerization reactor with a volume of 500 mL and a length-to-diameter ratio of 6:1. The full-load capacity of the unit was 1 kg polymer / h. Before the reaction began, the reactor and pipeline jacket of the continuous polymerization reactor were heated to 150°C, and the reactor was stirred and heated. Once the set temperature was reached, the feed pump was started to begin feeding Isohexanes at a rate of 5.0 L / h. The purpose of the oil flushing was to rinse away any residual polymer and other impurities in the polymerization reactor and material delivery pipelines. The oil flushing lasted for half an hour. The feed rates of Isohexanes solvent, propylene, and ethylene were adjusted to 2.6 L / h, 1350 g / h, and 60 g / h, respectively. The feed rate of the main catalyst was 7.0 μmol / h. Co-catalyst 1 was triisobutylaluminum (TIBA), diluted 120 times, with an Al / M ratio (molar ratio of aluminum in TIBA to transition metal in the main catalyst) of 500. Co-catalyst 2 was N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate, diluted 120 times, with a B / M ratio (molar ratio of boron in borate to transition metal in the main catalyst) of 1.3. The reaction pressure was 3 MPa. After the temperature stabilized, the main catalyst was added to initiate the polymerization reaction, with a reaction residence time of approximately 13.6 min. After the polymerization reaction stabilized, the polymer was collected after quenching and flash devolatilization, and the resulting propylene-based copolymer was characterized, as shown in Table 2.

[0160] In this embodiment, the main catalyst is

[0161] Examples 2-8, Comparative Examples 1-3

[0162] A propylene-based copolymer, specifically a propylene-ethylene copolymer, is prepared differently from that in Example 1, with different process parameters, as shown in Table 1; process parameters not shown in Table 1 are the same as in Example 1. Characterization data for each propylene-based copolymer are shown in Table 2.

[0163] Table 1

[0164]

[0165]

[0166] Table 2

[0167]

[0168] According to Tables 1 and 2, by adjusting the monomer ratio of propylene / ethylene and the polymerization temperature, the density of the resulting propylene-based copolymer can vary from 0.861 to 0.871 g / cm³. 3The density falls within the typical range for polyolefin elastomer materials. On the other hand, variations in the propylene / ethylene monomer ratio and polymerization temperature will cause differences in the molecular weight of the propylene-based copolymer. Overall, the melt index and M... w The γ value is inversely proportional to the molecular weight; the propylene copolymer has a PDI < 3 and a narrow molecular weight distribution. Under the polymerization conditions of Examples 1-8, the γ value of the propylene copolymer is > 90%.

[0169] The propylene-based elastomer materials in Comparative Examples 1-3, which show significant differences, have γ values ​​of 22%, 37%, and 3%, respectively. Specifically, the aspect ratio of the reactors used in Comparative Examples 1-2 exceeds the preferred range of (5-10):1 of this invention, resulting in a dual-melting-point polymerization product. Structural and compositional analysis indicates that the polymerization product is multiphase. In contrast, Comparative Example 3 is a homopolymer polypropylene material with high crystallinity and a high melting point, thus its γ value is only 3%.

[0170] Application examples

[0171] A cast polypropylene film includes a polypropylene base material (Yanshan Petrochemical ternary copolymer polypropylene F5606) and a modifier, wherein the modifier is a propylene-based copolymer provided in Examples 1-8 and Comparative Examples 1-3, and the mass percentage of the modifier is 15%; and an F5606 film without any modifier is used as a blank control example.

[0172] The method for preparing the cast polypropylene film includes:

[0173] (1) Preparation of blend: First, the polypropylene base material and the modifier are blended and extruded in a Ruya 26 extruder (RXT26-900-22-58). The temperature settings of each zone in the extruder are shown in the table below. The extruder speed is set to 400 rpm to obtain polypropylene / modifier blend granules for cast film.

[0174] partition Zone 1 Zone 2 Three Districts District 4 Fifth District machine head Temperature (°C) 180 200 200 200 200 200

[0175] (2) Preparation of cast polypropylene film: Cast film was prepared on a Guangdong Putong single-layer casting machine (FDOU-22). The temperature was set to 200℃, the screw speed was set to 27rpm, the casting roller speed was set to 3.0rpm, the roller temperature was controlled at 75℃, and the other rollers rotated in the same direction without introducing the stretch ratio. A cast polypropylene film with a thickness of 35μm was prepared.

[0176] Heat sealing performance test method:

[0177] The initial heat-sealing temperature, hot-tack strength, and heat-sealing temperature range of the test samples were determined according to the method in standard GB / T 27740-2011. The samples were heated using a single blade, with a heat-sealing temperature of 106-130℃, a temperature gradient of 1℃, a heat-sealing pressure of 0.238 MPa, a residence time of 1 s, and one heat-sealing cycle. The test speed was set at 300 mm / min, and the gauge length was 50 mm. The maximum load at which the sample broke was recorded. Taking a heat-sealing temperature of 116℃ as an example, the average of the maximum loads of the five samples at this heat-sealing temperature is the heat-sealing strength of the material.

[0178] Determination of initial heat sealing temperature: If the heat sealing strength of the sample at a certain temperature is ≥1N / 15mm, and the heat sealing strength of the sample at a temperature lower than this temperature is <1N / 15mm, then this temperature is the initial heat sealing temperature of the sample; the heat sealing temperature range is determined by the temperature range where the heat sealing strength is higher than 4N / 15mm.

[0179] The test data is shown in Table 3:

[0180] Table 3

[0181]

[0182]

[0183] As can be seen from the data in Table 3, the propylene-based copolymer provided by the present invention, when used as a modifier in the heat-sealing layer of CPP cast film, exhibits excellent properties of reducing the initial sealing temperature and widening the heat-sealing temperature range due to its improved γ value.

[0184] The addition of elastomer materials can reduce the sealing temperature of the cast film. Specifically, comparing the polymers of Example 1 and Comparative Examples 1-3, which exhibit the same / similar density in Table 3, it can be seen that the propylene-based copolymer of Example 1, as a modifier, gives the film a lower sealing temperature of 113°C, while the sealing temperatures of the films modified by the polymers of Comparative Examples 1-3 are 117°C, 117°C, and unsealed, respectively. Furthermore, the lower sealing temperature also provides a relatively wider heat-sealing temperature range for the film. The heat-sealing temperature range of the film modified by Example 1 is 113-118°C, while the heat-sealing temperature range of the films modified by Comparative Examples 1-2 is 117-118°C. The propylene-based copolymer of the present invention broadens the heat-sealing temperature range of the film, which is beneficial for reducing wrinkled or broken defective products and achieving better stable control of the production line.

[0185] Furthermore, comparing Examples 1-5 in Table 3, it can be seen that the ethylene content in the propylene-based copolymer affects the initial sealing temperature of the blended film. The reason is presumably that when the ethylene content in the copolymer sample is high, it can better disrupt the crystallization of propylene, reduce the grain size and crystal thickness of polypropylene crystals. During the heat sealing process, the polymer chains with high ethylene content will move first, thus reaching the initial sealing temperature earlier. Conversely, the ethylene insertion rate decreases, and the initial sealing temperature increases, which has an adverse effect on reducing the initial sealing temperature and widening the heat sealing temperature range.

[0186] The applicant declares that this invention illustrates the propylene-based copolymer, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the products of this invention, additions of auxiliary components, and selection of specific methods, all fall within the protection and disclosure scope of this invention.

Claims

1. A propylene-based copolymer, characterized in that, The weight-average molecular weight of the propylene copolymer is 2.0 × 10⁻⁶. 4 -40.0×10 4 g / mol, density 0.860-0.890 g / cm³ 3 ; The γ value of the propylene copolymer is ≥80%, and the formula for calculating the γ value is shown in Formula A: γ = 100% × m1 / m0 (Formula A); Wherein, m1 represents the mass of soluble matter in the propylene copolymer measured by temperature gradient cross-chromatography at a first temperature, m0 represents the injection mass of the propylene copolymer for temperature gradient cross-chromatography testing, and the first temperature is ≤40℃; The organic solvent used in the temperature gradient cross-chromatographic test was trichlorobenzene.

2. The propylene-based copolymer according to claim 1, characterized in that, The molecular weight distribution of the propylene copolymer is 2.0-4.

0.

3. The propylene-based copolymer according to claim 1, characterized in that, The propylene copolymer has a melt index of 1-80 g / 10 min at 230°C and a load of 2.16 kg.

4. The propylene-based copolymer according to any one of claims 1-3, characterized in that, The propylene-based copolymer is a copolymer of propylene and a first olefin, wherein the first olefin includes any one or a combination of at least two of ethylene and C4-C20 α-olefins.

5. The propylene-based copolymer according to claim 4, characterized in that, The first olefin includes any one or a combination of at least two of ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, and 1-dodecene.

6. The propylene-based copolymer according to claim 4, characterized in that, The mass percentage of the structural unit based on the first olefin in the propylene copolymer is 5-20%.

7. A method for preparing a propylene-based copolymer as described in any one of claims 1-6, characterized in that, The preparation method includes: polymerizing propylene and a first olefin under the catalysis of a catalyst to obtain the propylene-based copolymer.

8. The preparation method according to claim 7, characterized in that, The catalyst includes a main catalyst, which includes at least one of a transition metal compound with the structure shown in Formula I and a metallocene compound with the structure shown in Formula II. Equation I; Among them, R1-R 16 Each is independently selected from any one of hydrogen, C1-C30 straight-chain or branched alkyl, C1-C30 alkoxy, C3-C30 cycloalkyl, C3-C30 cycloalkyloxy, C6-C30 aryl, C6-C30 aryloxy, and C3-C30 heteroaryl; M1 is selected from any one of the metals in group IVB; X1 and X2 are each independently selected from any one of halogen, C1-C10 straight-chain or branched alkyl, C1-C10 alkoxy, C3-C10 cycloalkyl, C3-C10 cycloalkyloxy, C6-C14 aryl, C6-C14 aryloxy, and C7-C30 arylalkyl. L is selected from any one of C1-C10 straight-chain or branched alkylene groups and C3-C10 cycloalkylene groups; Formula II; Among them, R 21 R 25 R 29 R 30 Each is independently selected from any one of hydrogen, substituted or unsubstituted C1-C30 straight-chain or branched alkyl groups, or substituted or unsubstituted C3-C30 cycloalkyl groups; R 22 R 23 R 24 R 26 R 27 R 28 Each is independently selected from any one of hydrogen, substituted or unsubstituted C1-C30 straight-chain or branched alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 alkenyl, and substituted or unsubstituted C1-C30 alkoxy. The R 22 R 23 R 24 R 26 R 27 R 28 Any two adjacent groups in the group may be connected by chemical bonds to form a ring or not; Y is selected from any one of carbon, silicon, or germanium; Q1 and Q2 are each independently selected from any one of the following: substituted or unsubstituted C1-C30 straight-chain or branched alkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C3-C30 heteroaryl groups; M2 is selected from any one of the metals in group IVB; X3 and X4 are each independently selected from any one of halogen, amino, substituted or unsubstituted C1-C30 straight-chain or branched alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 alkylamino, substituted or unsubstituted C6-C30 arylamino, and substituted or unsubstituted C7-C30 arylalkyl. The substituents are each independently selected from at least one of halogens, amino groups, C1-C10 straight-chain or branched alkyl groups, C3-C10 cycloalkyl groups, silyl groups, C6-C30 aryl groups, and C3-C30 heteroaryl groups.

9. The preparation method according to claim 7 or 8, characterized in that, The catalyst also includes a co-catalyst, which includes any one or a combination of at least two of the compounds with the structure shown in Formula III, Formula IV, Formula V, and Formula VI. Formula III; Among them, R 31 R 32 R 33 Each is independently selected from any one of hydrogen, halogen, C1-C30 hydrocarbon group, or halogen-substituted C1-C30 hydrocarbon group; n is an integer ≥ 2; Formula IV; Where Z represents aluminum or boron; R 41 R 42 R 43 Each is independently selected from any one of halogen, C1-C30 hydrocarbon group, or halogen-substituted C1-C30 hydrocarbon group; Wherein, L represents a neutral Lewis base or a cationic Lewis base; Z is selected from any one of the elements in Group 13; A is independently selected from any one of substituted or unsubstituted C1-C30 hydrocarbon groups and substituted or unsubstituted C1-C30 hydrocarbon oxy groups; the substituents in A are independently selected from at least one of halogen, C1-C30 hydrocarbon oxy group, and C1-C30 hydrocarbon silyl group.

10. The preparation method according to claim 7, characterized in that, The apparatus for the polymerization reaction includes a batch reactor or a circulating reactor.

11. The preparation method according to claim 10, characterized in that, The batch reactor is a single reactor or several reactors connected in series, and the length-to-diameter ratio of the reactor is (5-10):

1.

12. The preparation method according to claim 10, characterized in that, The circulation ratio of the circulating loop reactor is 1-1000.

13. The preparation method according to claim 7, characterized in that, The polymerization reaction is carried out in the presence of a solvent.

14. The preparation method according to claim 7, characterized in that, The polymerization reaction is carried out at a temperature of 50-200℃.

15. The preparation method according to claim 14, characterized in that, The polymerization reaction is carried out at a temperature of 80-180℃.

16. The preparation method according to claim 7, characterized in that, The polymerization reaction is carried out at a pressure of 0.1-10 MPa.

17. The preparation method according to claim 16, characterized in that, The polymerization reaction is carried out at a pressure of 1-5 MPa.

18. The use of a propylene-based copolymer as described in any one of claims 1-6 in a polyolefin membrane material.

19. A polyolefin film, characterized in that, The polyolefin film comprises a propylene-based copolymer as described in any one of claims 1-6.

20. The polyolefin membrane according to claim 19, characterized in that, The polyolefin film is a polypropylene film.

21. The polyolefin membrane according to claim 20, characterized in that, The polyolefin film is a cast polypropylene film.

22. The polyolefin membrane according to claim 19, characterized in that, The polyolefin film includes a heat-sealing layer, which includes a propylene-based copolymer as described in any one of claims 1-6.

23. The polyolefin membrane according to claim 22, characterized in that, The mass percentage of the propylene-based copolymer in the heat-sealing layer is 1-50%.

24. The polyolefin membrane according to claim 23, characterized in that, The mass percentage of the propylene-based copolymer in the heat-sealing layer is 5-30%.

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