Propenyl copolymer as well as preparation method and application thereof

Abstract

The invention provides a propenyl copolymer as well as a preparation method and application thereof. The weight-average molecular weight of the propenyl copolymer is 2.0 * 10 < 4 >-40.0 * 10 < 4 > g / mol, and the density of the propenyl copolymer is 0.860-0.890 g / cm < 3 >. The gamma value of the propenyl copolymer is greater than or equal to 80%. Through design of specific molecular weight, density and gamma value, regulation and control of material structure and composition are realized. The propenyl copolymer is used for a polyolefin film material, and can effectively reduce the initial sealing temperature and broaden the heat sealing temperature range, so that the polyolefin film containing the propenyl copolymer has significantly improved heat sealing performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, in particular to the field of polyolefins, and specifically to a propylene-based copolymer and a preparation method and application thereof. Background Art

[0002] Polypropylene (PP) is a kind of polyolefin material. It is transparent and light in appearance. It also has excellent chemical resistance, high temperature resistance, electrical insulation and wear resistance. It is widely used in food and drug packaging, automotive parts, clothing and daily necessities, fiber products and other fields. With the improvement of people's pursuit of material living standards, the use of polypropylene film materials for food packaging has increased year by year. From the perspective of technology, the common polypropylene packaging film material is mainly cast polypropylene film (CPP cast film), which is a non-stretched, non-directional flat extruded film produced by melt casting and quenching. It has the characteristics of good transparency, high gloss, good stiffness, good moisture resistance, and excellent heat resistance. The production process of CPP cast film includes: feeding, weighing, melt extrusion, thickness measurement, trimming, corona, traction, winding, slitting, packaging and warehousing.

[0003] According to different functionalities, the layer structure of traditional CPP cast film can be divided into three or more layers, among which the heat sealing layer mainly plays the role of heating, bonding and sealing during the sealing process. The indicators of concern for the heat sealing layer usually include: heat sealing strength, sealing start temperature and heat sealing temperature range; the appropriate heat sealing strength can ensure the strength of the seal and ensure that the packaging bag will not open during transportation and transfer, causing the contents to spill; the lower sealing start temperature can reduce the energy consumption of packaging and improve the efficiency of sealing. However, the lower the sealing start temperature, the softer the film material will be, the more likely it will self-stick, and the opening performance will become unstable, which may even cause the production line to stop in severe cases; on the other hand, excellent heat sealing performance also includes a suitable heat sealing temperature range, the purpose of which is to ensure that it can be "sealed" without causing the film thickness at the sealing position to become thinner and wrinkled, affecting the heat sealing strength and appearance.

[0004] Studies have shown that heat-sealing film prepared by mixing low-melting-point polyolefin elastomer materials into crystalline polypropylene can reduce the heat-sealing temperature and improve the toughness and tear resistance of the film. For example, CN103153618A discloses a polyolefin composite film having a five-layer structure formed in sequence by surface layer / middle layer / core layer / middle layer / surface layer, wherein the surface layer contains 0-50% by weight of propylene-α-olefin random copolymer and / or 1-butene-α-olefin copolymer, and 50-100% by weight of propylene polymer with a melting point of 120-170°C, and has the characteristics of low-temperature heat sealing, good heat sealing strength and transparency. CN106626654A discloses a polyolefin film material with a lower heat-sealing temperature, comprising a top surface layer, two core layers and a bottom surface layer, which are distributed in sequence and have a total of 5 layers. The top surface layer and the bottom surface layer are prepared from the following components: 50-80 parts of propylene copolymer, 20-40 parts of olefin-based elastomer, 1-6 parts of anti-adhesive agent, and 1-4 parts of lubricant. The film material has a low heat-sealing temperature and a wide heat-sealing temperature range. Its use effect on a high-speed sealing automatic packaging machine is better than that of traditional heat-sealing POF (polyolefin heat shrinkable film) products. However, the existing heat-sealing layer film material still has difficulty in taking into account both the low sealing temperature and the appropriate heat-sealing temperature range, and the heat-sealing performance is insufficient.

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

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a propylene-based copolymer and a preparation method and application thereof. The propylene-based copolymer has a specific design of density, molecular weight and γ value to achieve the regulation of material structure and composition. When used in polyolefin film materials, it can reduce the sealing temperature and widen the heat-sealing temperature range, so that the polyolefin film containing it has significantly improved heat-sealing performance.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[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 4 -40.0×10 4 g / mol, density is 0.860-0.890g / cm 3 ; The γ value of the propylene-based copolymer is ≥80%, and the calculation formula of the γ value is shown in Formula A:

[0009] γ=100%×m1 / m0Formula A.

[0010] In formula A, m1 represents the amount of soluble matter measured by temperature gradient cross chromatography at a first temperature for the propylene-based copolymer, m0 represents the injection mass of the propylene-based copolymer for temperature gradient cross chromatography test, and the first temperature is ≤40°C.

[0011] The propylene-based copolymer provided by the present invention has a specific molecular weight and density, and its density belongs to the range of typical polyolefin elastomer materials; at the same time, the propylene-based copolymer has a relatively high γ value. Through the design of density, molecular weight and γ value, the material structure and composition are regulated, so that the propylene-based copolymer is used for polyolefin film materials, which can effectively reduce the sealing temperature, widen the heat sealing temperature range, and improve the 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. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0013] In the present invention, the weight average molecular weight (M w ) is 2.0×10 4 -40.0×10 4 g / mol, for example, 3.0×10 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 point values. Due to space limitations and for the sake of simplicity, the present invention will no longer exhaustively list the specific point values ​​included in the range, preferably 3.0×10 4 -30.0×10 4 g / mol, more preferably 3.0×10 4 -35.0×10 4 g / mol.

[0014] Preferably, the molecular weight distribution of the propylene-based 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, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, and 2.5-3.5 is further preferred.

[0015] Exemplarily, the weight average molecular weight (M w ), number average molecular weight (M n ) was obtained by gel permeation chromatography (GPC) test, and polystyrene was used as the standard sample for GPC test; the molecular weight distribution is M w / M n .

[0016] In the present invention, the density of the propylene-based copolymer is 0.860-0.890 g / cm 3 , for example, it can be 0.862 g / cm 3 , 0.865g / cm 3 , 0.868g / cm 3 、0.870g / cm 3 , 0.872g / cm 3 、0.875g / cm 3 、0.878g / cm 3 、0.880g / cm 3 , 0.882g / cm 3 , 0.885g / cm 3 or 0.888 g / cm 3 , and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, preferably 0.860-0.885 g / cm 3 , further preferably 0.860-0.880 g / cm 3 .

[0017] Illustratively, the density of the propylene-based copolymer is measured by the method in ASTM D792-2021 or ASTM D792-13.

[0018] In the present invention, the γ value of the propylene-based copolymer is ≥80%, for example, it can be 82%, 85%, 88%, 90%, 92%, 95%, 98%, 99% or 100%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0019] In the present invention, γ=100%×m1 / m0, m1 represents the amount of soluble matter measured by temperature gradient cross chromatography (TGIC) at a first temperature (≤40°C) for the propylene-based copolymer, and m0 represents the injection mass of the propylene-based copolymer for temperature gradient cross chromatography test.

[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 and the combined effects of adsorption-desorption and crystallization properties to separate different components of polyolefins under a certain solvent flow rate and temperature change.

[0021] Preferably, the first temperature is ≤40°C, for example, it may be 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C or 38°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0022] Preferably, the propylene-based copolymer (test sample) is subjected to a temperature gradient cross chromatography test, and the test sample is extracted in an organic solvent used for the test, and the extraction temperature is a first temperature (≤40° C.).

[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 point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

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

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

[0026] Preferably, the melt index of the propylene-based copolymer at 230° C. and a load of 2.16 kg is 1-80 g / 10 min, for example, 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 point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

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

[0028] Preferably, the melting temperature (T m ) is 80-130°C, for example, it can be 82°C, 85°C, 88°C, 90°C, 92°C, 95°C, 98°C, 100°C, 102°C, 105°C, 108°C, 110°C, 112°C, 115°C, 118°C, 120°C, 122°C, 125°C or 128°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the said range, and 95-120°C is further preferred.

[0029] Exemplarily, the melting temperature (T m ) was obtained by differential scanning calorimetry (DSC) testing, and the testing process was as follows: the copolymer was first heated to 200°C, maintained for 5 minutes to eliminate the thermal history, then cooled to -60°C, and then heated again to 200°C. The rate of increase and the rate of decrease during the entire test process were controlled at 10°C / min, respectively, and the measurement result during the second heating process was calibrated as the melting temperature.

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

[0031] Wherein, the C4-C20 α-olefin may be C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20 α-olefin.

[0032] Preferably, the first olefin includes any one of ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, and 1-dodecene, or a combination of at least two of them. ethylene, any one of 1-hexene, and 1-octene, or a combination of at least two of them are further preferred, and ethylene is more preferred.

[0033] Preferably, the mass percentage of the structural unit based on the first olefin in the propylene-based 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%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0034] Most of the constituent units in the propylene-based copolymer are derived from propylene. Preferably, the molar percentage of the structural units based on propylene in the propylene-based copolymer is 50-97%, for example, it can be 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95%, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the range, preferably 60-90%, more preferably 70-90%, and more preferably 80-90%.

[0035] The molar percentage of structural units based on the first olefin (comonomer, ethylene and / or C4-C20 α-olefin) in the propylene-based 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%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the range, preferably 10-40%, further preferably 10-30%, and more preferably 10-20%.

[0036] In a second aspect, the present invention provides a method for preparing the propylene-based copolymer as described in the first aspect, the preparation 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, and the main catalyst comprises at least one of a transition metal compound having a structure shown in Formula I and a metallocene compound having a structure shown in Formula II:

[0038]

[0039] In Formula I, R1-R16 Each is independently selected from any one of hydrogen, C1-C30 straight 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 one of the Group IVB metals.

[0041] In formula I, X1 and X2 are each independently selected from any one of halogen, C1-C10 straight 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 a C1-C10 straight chain or branched chain alkylene group and a C3-C10 cycloalkylene group.

[0043]

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

[0045] In Formula 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 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 ring 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 a substituted or unsubstituted C1-C30 straight or branched alkyl group, a substituted or unsubstituted C6-C30 aryl group, and a substituted or unsubstituted C3-C30 heteroaryl group;

[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 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, the substituted substituents are each independently selected from at least one of halogen, amino, C1-C10 straight or branched alkyl, C3-C10 cycloalkyl, silane, C6-C30 aryl, and C3-C30 heteroaryl.

[0052] In the present invention, the "substituted or unsubstituted" group may be substituted with one substituent or with multiple substituents. When there are multiple (at least 2) substituents, they may be the same or different substituents. When the same expressions are mentioned below, they have the same meaning. Unless otherwise specified, the selection range of the substituents substituted in the metallocene compound shown in Formula II is as shown above and will not be repeated.

[0053] The catalytic system plays an important role in the polymer preparation process. The propylene-based copolymer can be prepared using a catalyst system comprising a transition metal compound of the structure shown in the above formula I and a metallocene compound of the structure shown in the formula II (also a transition metal compound). In the present invention, due to the use of a catalyst system comprising a main catalyst having a specific structure (at least one of the transition metal compound of the structure shown in the formula I and the metallocene compound of the structure shown in the formula II), a suitable content of comonomer (the first olefin, ethylene and / or an α-olefin of C4-C20) can be introduced, so that the obtained propylene-based copolymer has a specific molecular weight M w , density, molecular weight distribution and γ value.

[0054] In the present invention, the C1-C30 straight chain or branched alkyl group can be a straight chain or branched 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., preferably a C1-C20 straight chain or branched alkyl group, further preferably a C1-C10 straight chain or branched alkyl group, illustratively including but 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 the present invention, the C1-C30 alkoxy group can be a straight chain or branched chain alkoxy 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., preferably a C1-C20 alkoxy group, and more preferably a C1-C10 alkoxy group. A specific example is a monovalent group formed by connecting the above straight chain or branched chain alkyl group to O.

[0056] In the present invention, the C3-C30 cycloalkyl group can be a cycloalkyl group of C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C25, C26 or C28, including a monocyclic alkyl group or a polycyclic alkyl group, preferably a C3-C20 cycloalkyl group, further preferably a C3-C10 cycloalkyl group, illustratively including but not limited to: cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantyl and the like.

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

[0058] In the present invention, the C6-C30 aromatic groups can be aromatic groups of C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, and C6-C20 aromatic groups are further preferred, including monocyclic aromatic groups and condensed-ring aromatic groups, illustratively including but not limited to: phenyl, biphenyl, terphenyl, quaterphenyl, naphthyl, anthracenyl, phenanthrenyl, binaphthyl, benzocyclopentenyl, benzocyclopentadienyl, and the like.

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

[0060] In the present invention, the C3-C30 heteroaryl group can be a heteroaryl group of C3, C4, C5, C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, preferably a C3-C20 heteroaryl group, wherein the heteroatom can be N, O, S, etc.; including a monocyclic heteroaryl group or a condensed ring heteroaryl group, illustratively including but not limited to: pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazine, furanyl, thienyl, pyrrolyl, quinolyl, isoquinolyl, quinoxalinyl, quinazolinyl, benzofuranyl, benzothienyl, indolyl, dibenzofuranyl, dibenzothienyl, carbazolyl, N-phenylcarbazolyl, etc.

[0061] In the present invention, the halogen includes fluorine, chlorine, bromine and iodine.

[0062] In the present invention, the C1-C10 straight chain or branched alkyl group can be a straight chain or branched alkyl group of C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, illustratively including but 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 chain alkylene group may be a straight chain or branched chain alkylene group of C1, C2, C3, C4, C5, C6, C7, C8, C9, or C10, and a specific example thereof is a divalent group formed by losing one H from the above-mentioned straight chain or branched chain 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, or C10, and specific examples include monovalent groups formed by connecting the above straight-chain or branched alkyl groups to O.

[0065] In the present invention, the C3-C10 cycloalkyl group can be a cycloalkyl group of C3, C4, C5, C6, C7, C8, C9, or C10, including a monocyclic alkyl group or a polycyclic alkyl group, illustratively including but not limited to: cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantyl, and the like.

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

[0067] The C3-C10 cycloalkyloxy group may be a C3, C4, C5, C6, C7, C8, C9, or C10 cycloalkyloxy group, and a specific example is a monovalent group formed by connecting the above cycloalkyl group to O.

[0068] In the present invention, the C6-C14 aromatic groups may be aromatic groups of C6, C9, C10, C12, C13, C14, etc., illustratively including but not limited to phenyl, biphenyl, naphthyl, anthracenyl, phenanthryl, etc.

[0069] The C6-C14 aryloxy groups may be aryloxy groups of C6, C9, C10, C12, C13, C14, etc., and specific examples thereof are monovalent groups formed by connecting the above aryl groups 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. Specific examples are monovalent groups formed by connecting the above aryl groups to straight-chain or branched alkyl groups, a typical example of which is benzyl (phenylmethyl).

[0071] In the present invention, the C2-C30 alkenyl groups may 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, illustratively including but not limited to: vinyl, propenyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, butadienyl, pentadienyl, etc.

[0072] In the present invention, the C1-C30 alkylamino group can be an alkylamino group of C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C25, C26, C28, etc., which is a monovalent group in which at least one hydrogen in -NH2 is replaced by the above-mentioned straight-chain or branched alkyl group.

[0073] In the present invention, the C6-C30 arylamino group can be an arylamino group of C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, which is a monovalent group in which at least one hydrogen in -NH2 is replaced by the above aryl group.

[0074] Preferably, in Formula I, the R1-R 16 each independently selected from hydrogen, C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) straight or branched alkyl, C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) alkoxy, C3-C10 (e.g., C4, C5, C6, C7, C8, C9, etc.) cycloalkyl, C6-C20 (e.g., C6, C9, C10, C1 Any one of C2, C14, C16, C18, etc.) aryl, C6-C20 (e.g., C6, C9, C10, C12, C14, C16, C18, etc.) aryloxy, C3-C20 (e.g., C4, C5, C6, C9, C10, C12, C14, C16, C18, etc.) heteroaryl, and any one of hydrogen, C1-C6 straight-chain or branched alkyl, phenyl, and carbazolyl is further preferred.

[0075] Furthermore, the transition metal compound of the structure shown in Formula I preferably has a 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 or branched alkylene, C4-C8 (e.g., C5, C6, C7, etc.) cycloalkylene, and more preferably Any one of the above, -* represents the attachment site of the group; m' is selected from an integer ≥1, for example, it can be 1, 2, 3, etc., more preferably 1 or 2.

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

[0079]

[0080] Preferably, in Formula I, Formula I-1, and Formula I-2, R1, R3, R6, R7, 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 or branched alkyl, C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) alkoxy, C3-C10 (e.g., C4, C5, C6, C7, C8, C9, etc.) cycloalkyl, C6-C20 (e.g., C6, C9, C10, C12, C14, C16, C18, etc.) aryl, Any one of C6-C20 (e.g., C6, C9, C10, C12, C14, C16, C18, etc.) aryloxy, C3-C20 (e.g., C4, C5, C6, C9, C10, C12, C14, C16, C18, etc.) heteroaryl, further preferably any one of hydrogen, C1-C6 straight chain or branched alkyl, phenyl, carbazolyl, more preferably hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl or carbazolyl.

[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 of the structure shown in Formula I comprises any one or a combination of at least two of the following compounds:

[0083]

[0084]

[0085] Among them, Bn represents benzyl, Cz represents carbazolyl Preferably, the 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 any one of hydrogen, substituted or unsubstituted C1-C10 (e.g. C2, C3, C4, C5, C6, C7, C8, C9, etc.) straight chain or branched chain alkyl, substituted or unsubstituted C3-C10 (e.g. C2, C3, C4, C5, C6, C7, C8, C9, etc.) cycloalkyl, more preferably any one of hydrogen, C1-C6 straight chain or branched chain alkyl.

[0087] Preferably, in Formula II, the 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-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 any one of hydrogen, C1-C6 straight chain or branched alkyl, phenyl, and naphthyl is more preferred.

[0088] In Formula II, the R 22 , R 23 , R 24 , R 26 , R 27 , R 28 Any two adjacent groups in the formula are connected to form a ring by chemical bonds or not; wherein, "R 22 , R 23 , R 24 , R 26 , R 27 , R 28 "There is no connection between any two adjacent groups" means that the aforementioned groups are 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 groups are connected by a chemical bond to form a ring" means that any two adjacent groups in the above mentioned groups are connected by a chemical bond to form a fused ring structure.

[0089] Preferably, in Formula II, the R 22 , R 23 , R 24 , R 26, R 27 , R 28 Any two adjacent groups in the above are connected by chemical bonds to form a ring Cy or are not connected, and the ring Cy is selected from any one of a substituted or unsubstituted C3-C20 (e.g., C4, C5, C6, C9, C10, C12, C14, C16, C18, etc.) alicyclic rings, substituted or unsubstituted C6-C20 (e.g., C6, C9, C10, C12, C14, C16, C18, etc.) aromatic rings, and more preferably The dotted line represents the fused ring bond of ring Cy.

[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.) linear or branched alkyl, substituted or unsubstituted C6-C20 (e.g., C6, C9, C10, C12, C14, C16, C18, etc.) aryl, 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, and any one of C1-C6 linear or branched alkyl and phenyl is further preferred.

[0091] Preferably, in Formula II, the 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 halogen (fluorine, chlorine, bromine, iodine), C1-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, etc.) straight chain or branched chain alkyl, phenyl, benzyl, more preferably chlorine, C1-C6 straight chain or branched chain alkyl.

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

[0094]

[0095]

[0096] Here, Me represents a methyl group, and Ph represents a phenyl group.

[0097] Preferably, the catalyst further comprises a co-catalyst, and the co-catalyst comprises any one or a combination of at least two of the compound represented by formula III, the compound represented by formula IV, the compound represented by formula V, and the compound represented by formula VI;

[0098]

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

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

[0101]

[0102] In formula IV, Z is aluminum or boron.

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

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

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

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

[0107] Z is selected from any one of the Group 13 elements.

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

[0109] In the present invention, the C1-C30 hydrocarbon groups may 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 , C3, C4, C5, C6, C8, C10, C12, C14, C15, C16, C18, C20, C22, C24, C25, C26, C28, etc.) straight chain or branched alkyl, C3-C30 (e.g. C4, C5, C6, C8, C10, C12, C14, C15, C16, C18, C20, C22, C24 , C25, C26, C28, etc.) cycloalkyl, C6-C30 (e.g., C6, C9, C10, C12, C14, C16, C18, C20, C22, C24, C26 or C28, etc.) aryl, C7-C30 (e.g., C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C C20, C22, C24, C25, C26, C28, etc.) aryl alkyl, C7-C30 (e.g., C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C20, C22, C24, C25, C26, C28, etc.) alkyl aryl, further specific examples are as described above and will not be repeated here.

[0110] In the present invention, the C1-C30 alkoxy group can be an alkoxy 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 thereof is a monovalent group formed by connecting the aforementioned alkoxy group to an O atom.

[0111] In the present invention, the C1-C30 hydrocarbylsilyl group may be a hydrocarbylsilyl 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., which is a monovalent group in which at least one hydrogen in -SiH3 is replaced by the aforementioned hydrocarbyl group.

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

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

[0114] Preferably, the molar ratio of the aluminum element in the trialkylaluminum to the transition metal element 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 compound of the structure shown in Formula V and the compound of the structure shown in Formula VI include borate compounds, specifically including any one or a combination of at least two of trisubstituted ammonium salt borates, dialkylammonium salt borates, and trisubstituted phosphonium salt borates.

[0116] Preferably, the trisubstituted ammonium salt type borate comprises trimethylammonium tetraphenylborate, methyldioctadecylammonium tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, methyltetradecyloctadecylammonium tetraphenylborate, N,N-dimethylanilinium tetraphenylborate, N,N-diethylanilinium tetraphenylborate, N,N-dimethyl(2,4,6-trimethylanilinium)tetraphenylborate, trimethylammonium tetra(pentafluorophenyl)borate, methyldioctadecylammonium tetra(pentafluorophenyl)borate, methyldioctadecylammonium tetra(pentafluorophenyl)borate, triethylammonium tetra(pentafluorophenyl)borate, tripropylammonium tetra(pentafluorophenyl)borate, tri(n-butyl)ammonium tetra(pentafluorophenyl)borate, tri-sec-butylammonium tetra(pentafluorophenyl)borate, N,N-dimethylanilinium tetra(pentafluorophenyl)borate fluorophenyl) borate, N,N-diethylanilinium tetrakis(pentafluorophenyl)borate, N,N-dimethyl(2,4,6-trimethylanilinium)tetrakis(pentafluorophenyl)borate, trimethylammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate, triethylammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate, tripropylammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate, tri(n-butyl)ammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate Any one of or a combination of at least two of dimethyl (tert-butyl) ammonium tetrakis (2,3,4,6-tetrafluorophenyl) borate, N,N-dimethylanilinium tetrakis (2,3,4,6-tetrafluorophenyl) borate, N,N-diethylanilinium tetrakis (2,3,4,6-tetrafluorophenyl) borate, and N,N-dimethyl-(2,4,6-trimethylanilinium) tetrakis (2,3,4,6-tetrafluorophenyl) borate.

[0117] Preferably, the dialkylammonium salt type borate includes any one of dioctadecylammoniumtetrakis(pentafluorophenyl)borate, ditetradecylammoniumtetrakis(pentafluorophenyl)borate, and dicyclohexylammoniumtetrakis(pentafluorophenyl)borate, or a combination of at least two thereof.

[0118] Preferably, the trisubstituted phosphonium salt type borate includes any one of triphenylphosphonium tetrakis(pentafluorophenyl)borate, methyldi(octadecyl)phosphonium tetrakis(pentafluorophenyl)borate, tris(2,6-dimethylphenyl)phosphonium tetrakis(pentafluorophenyl)borate, or a combination of at least two thereof.

[0119] Preferably, the molar ratio of the boron element in the borate compound to the transition metal element 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 organic aluminum compound is further injected into the reaction device to remove moisture, and the polymerization reaction can be carried out in the presence of the organic aluminum compound. Specific examples of the organic aluminum compound may include any one or a combination of at least two of trialkylaluminum, dialkylaluminum halide, alkylaluminum dihalide, dialkylaluminum hydride, and alkylaluminum sesquihalide, illustratively including but not limited to: Al(C2H5)3, Al(C2H5)2H, Al(C3H7)3, Al(C3H7)2H, Al(i-C4H9)2H, Al(C8H 17 )3、Al(C 12 H 25 )3、Al(C2H5)(C 12 H 25 )2、Al(i-C4H9)(C 12 H 25 )2, Al(i-C4H9)2H, Al(i-C4H9)3, (C2H5)2AlCl, (i-C3H9)2AlCl, (C2H5)3Al2Cl3, or a combination of at least two thereof

[0121] The organoaluminum compound can be continuously injected into the reaction device, and in order to properly remove impurities such as water and oxygen, the organoaluminum compound can be injected in a ratio of about 0.1-10 mol / 1kg (for example, 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.) to the reaction medium injected into the reaction device.

[0122] In the present invention, the device used for the polymerization reaction is a continuous polymerization reaction device with reactors of different volumes and forms.

[0123] Preferably, the polymerization reaction apparatus comprises a tank reactor or a circulating loop reactor.

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

[0125] In a preferred technical solution, a kettle reactor is used as a polymerization device, which can be a non-stirring or stirring cylindrical container or a can container. By adjusting the aspect ratio of the reactor (reactor), the material entering the reactor will have a temperature distribution and a concentration distribution, further achieving the adjustment of the composition and structure of the polymer generated in different temperature zones in the microscopic region, and finally the propylene-based copolymer with a 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 point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

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

[0128] Preferably, the polymerization reaction is carried out in the presence of a solvent, that is, solution polymerization is adopted.

[0129] Preferably, the solvent includes any one of alkane solvents, halogenated alkane solvents, cycloalkane solvents, and aromatic solvents, or a combination of at least two thereof, and more preferably any one of n-hexane, cyclohexane, heptane, toluene, xylene, and isoalkane, or a combination of at least two thereof.

[0130] Preferably, the polymerization reaction is carried out in the presence or absence of a molecular weight regulator; the molecular weight regulator includes hydrogen, and further preferably the injection amount of hydrogen 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 point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0131] Preferably, the polymerization reaction temperature is 50-200°C, for example, it can be 60°C, 70°C, 80°C, 90°C, 100°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C or 190°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the range, and 80-180°C is further preferred.

[0132] Preferably, the polymerization reaction pressure 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 point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the range, and 1-5 MPa is further preferred.

[0133] Preferably, after the polymerization reaction is completed, a post-treatment step is further included, and the post-treatment includes quenching and / or devolatilization.

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

[0135] In a third aspect, the present invention provides a use of the propylene-based copolymer as described in the first aspect in a polyolefin film material.

[0136] In a fourth aspect, the present invention provides a polyolefin film, wherein the polyolefin film comprises the propylene-based copolymer as described in the first aspect.

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

[0138] Preferably, the polyolefin film (preferably a polypropylene film) comprises a heat-sealing layer, and the heat-sealing layer comprises the 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 (a heat-sealing layer comprising the propylene-based copolymer provided by the present invention); it can also be 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 the materials known in the art that can be used for polyolefin films are all suitable for 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%, and specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific points included in the range, and 5-30% is further preferred.

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

[0142] As a preferred technical solution of the present invention, the propylene-based copolymer is used as a modifier for the heat-sealing layer of the CPP cast film. Due to the improved γ value, it shows excellent properties of lowering the sealing temperature and widening the heat-sealing temperature range. Preferably, the sealing temperature of the heat-sealing layer is as low as 113°C, and the heat-sealing temperature is 113-118°C (for example, 114°C, 115°C, 116°C, 117°C), which widens the heat-sealing temperature range, thereby improving the heat-sealing performance of the polyolefin film.

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

[0144] In the propylene-based copolymer provided by the present invention, the material structure and composition are regulated by designing specific molecular weight, density and γ value. The propylene-based copolymer is used in polyolefin film materials, which can effectively reduce the sealing temperature, broaden the heat-sealing temperature range, and make the polyolefin film containing the propylene-based copolymer have significantly improved heat-sealing performance. DETAILED DESCRIPTION

[0145] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0146] As used herein, the terms "comprises," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0147] "Optionally" or "either" means that the subsequently described matter or event can or cannot occur, and that the description includes instances where the event occurs and instances where it does not.

[0148] In a specific embodiment, the transition metal compound of the structure shown in Formula I can be prepared by referring to the synthesis method disclosed in the prior art, for example, referring to US20040014950A1, CN116554378A, CN114230702B, CN116212960A and the document "Stereospecific Octahedral Group 4 Bis (phenolate) Ether Complexes for Olefin Polymerization", J.Am.Chem.Soc.2010,132,5566-5567, etc.

[0149] In one specific embodiment, the metallocene compound of the structure shown in Formula II can be prepared by referring to the synthesis method disclosed in the prior art, for example, referring to 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 onthe Polymerization Behavior of Bridged Zirconocene Catalysts", Organometallics1994,13,954-963, etc.

[0150] In the following specific embodiments of the present invention, the main testing methods for polymers 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 ) was obtained by gel permeation chromatography (GPC); chromatographic 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: measured using the method in ASTM D792-2021.

[0153] (3) Melt index: measured by the method of ASTM D1238-13 (230° C., load 2.16 kg).

[0154] (4) Melting temperature (T m ): The melting temperature was obtained using a differential scanning calorimeter (DSC 6000) manufactured by PerkinElmer. That is, after the temperature was raised to 200°C, the temperature was maintained at that temperature for 1 min, then lowered to -100°C, and the temperature was raised again to obtain the top of the DSC curve as the melting point. At this time, the rate of temperature rise and fall was 10°C / min, and the melting temperature was obtained during the second temperature rise.

[0155] (5) γ value: The polymer to be tested was injected into a temperature gradient crossover chromatograph (TGIC) for testing. The solvent used in the test was trichlorobenzene. The sample was extracted in 1,2,4-trichlorobenzene. The starting temperature of the extraction was 0°C, the heating rate was 1.0°C / min, the temperature was raised to 40°C, and the extraction was carried out for 40 min. The mass of soluble matter in the TGIC test was recorded as m1; the injection mass was m0, and γ = 100% × m1 / m0.

[0156] (6) Ethylene insertion rate: The ethylene insertion rate was determined by nuclear magnetic resonance (NMR) technology. First, the propylene copolymer sample was dissolved in deuterated tetrachloroethane solvent. The frequency corresponding to the magnetic field strength of the instrument was adjusted to between 300 and 600 MHz. The characteristic proton peaks corresponding to the ethylene and propylene units were measured and the integral areas were 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:

[0159] A small-scale continuous polymerization reaction device was used for polymerization experiments. The polymerization reaction was in the form of solution polymerization, the reaction unit was in the form of single-kettle polymerization, the reactor volume was 500mL, the aspect ratio was 6:1, and the capacity of the device at full load was 1kg polymer / h. Before the reaction started, the reactor and pipeline jacket heating of the continuous polymerization reaction device were set to 150°C, and the reactor was started to stir and heat up. After the temperature was raised to the corresponding set temperature, the feed pump was started to start the feeding of Isohexanes (isohexane) at a feed rate of 5.0L / h. The purpose of the oil transportation is to rinse the residual polymer and other impurities in the polymerization reactor and the material conveying pipeline, and the oil transportation was completed in half an hour. The feed rate of solvent Isohexanes was adjusted to 2.6L / h, the feed rate of propylene was 1350g / h, the feed rate of ethylene was 60g / h, the feed rate of the main catalyst was 7.0μmol / h, the cocatalyst 1 was triisobutylaluminum (TIBA), diluted 120 times, the Al / M ratio (the molar ratio of aluminum in TIBA to the transition metal in the main catalyst) was 500, the cocatalyst 2 was N,N-dimethylanilinium tetrakis (pentafluorophenyl) borate, diluted 120 times, the B / M ratio (the molar ratio of boron in borate to the transition metal in the main catalyst) was 1.3, and the reaction pressure was 3MPa. When the temperature was stable, the main catalyst was added to initiate the polymerization reaction, and the reaction residence time was about 13.6min; when the polymerization reaction was stable, the polymer was collected after quenching and deactivation, and the obtained 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, the preparation method of which is different from that of Example 1 in that the process parameters are different, as shown in Table 1; the process parameters not shown in Table 1 are the same as those of Example 1. The characterization data of each propylene-based copolymer are shown in Table 2.

[0163] Table 1

[0164]

[0165]

[0166] Table 2

[0167]

[0168] According to Table 1 and Table 2, by adjusting the monomer ratio of propylene / ethylene and the polymerization temperature, the density of the obtained propylene-based copolymer can be varied in the range of 0.861-0.871 g / cm 3The density belongs to the typical range of polyolefin elastomer materials. On the other hand, the molecular weight of propylene-based copolymers will be different due to the difference in the ratio of propylene / ethylene monomers and the polymerization temperature. Overall, the melt index and M w The PDI of the propylene-based copolymer is less than 3, and has a narrow molecular weight distribution. Under the polymerization conditions of Examples 1-8, the γ value of the propylene-based copolymer is greater than 90%.

[0169] The γ values ​​of the propylene-based elastomer materials in Comparative Examples 1-3, which are significantly different from the propylene-based elastomer materials, are 22%, 37% and 3%, respectively. Among them, the aspect ratio of the reactor used in Comparative Examples 1-2 exceeds the preferred range of (5-10):1 of the present invention, and the polymerization product has a double melting point phenomenon. From the structural and composition analysis, the polymerization product is multi-phase; while Comparative Example 3 is a homopolypropylene material with high crystallinity and high melting point, so the γ value is only 3%.

[0170] Application Examples

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

[0172] The preparation method of the cast polypropylene film comprises:

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

[0174] Partition Zone 1 Zone 2 Zone 3 District 4 District 5 Machine head Temperature(℃) 180 200 200 200 200 200

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

[0176] Heat sealing performance test method:

[0177] The method in standard GB / T 27740-2011 is used to determine the initial heat sealing temperature, hot tack strength and heat sealing temperature range of the sample to be tested. The sample is heated by a single knife, the heat sealing temperature is 106-130℃, the temperature gradient is 1℃, the heat sealing pressure is 0.238MPa, the dwell time is 1s, the number of heat sealing is 1 time, the test speed is set to 300mm / min, the gauge length is 50mm, and the maximum load when the sample is pulled off is recorded; taking the heat sealing temperature of 116℃ as an example, the average value of the maximum load of 5 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 is <1N / 15mm below this temperature, then this temperature is the initial heat sealing temperature of the sample; the heat sealing temperature range is determined by the temperature range in which the heat sealing strength is higher than 4N / 15mm.

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

[0180] Table 3

[0181]

[0182]

[0183] According to the data in Table 3, the propylene-based copolymer provided by the present invention is used as a modifier for the heat-sealing layer of the CPP cast film, and has excellent properties of lowering the sealing temperature and widening the heat-sealing temperature range due to its improved γ value.

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

[0185] In addition, by comparing Examples 1-5 in Table 3, it can be seen that the ethylene content in the propylene-based copolymer affects the sealing temperature of the blended film material. The reason is presumably that when the ethylene content in the copolymer sample is high, the crystallization of propylene can be better destroyed, and the grain size and chip thickness of the polypropylene crystal can be reduced. During the heat sealing temperature rise process, the polymer chain with a high ethylene content will move first, and thus reach the sealing temperature earlier. On the contrary, if the ethylene insertion rate decreases, the sealing temperature increases, which has an adverse effect on reducing the sealing temperature and widening the heat sealing temperature range.

[0186] The applicant declares that the present invention illustrates the propylene-based copolymer and its preparation method and application through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A propylene-based copolymer, characterized in that The weight average molecular weight of the propylene-based copolymer is 2.0×10 4 -40.0×10 4 g / mol, density is 0.860-0.890g / cm 3 ; The γ value of the propylene-based copolymer is ≥80%, and the calculation formula of the γ value is shown in Formula A: γ=100%×m1 / m0Formula A; Wherein, m1 represents the amount of soluble matter measured by using temperature gradient cross chromatography at a first temperature for the propylene-based copolymer, m0 represents the injection mass of the propylene-based copolymer for temperature gradient cross chromatography test, and the first temperature is ≤40°C.

2. The propylene-based copolymer according to claim 1, characterized in that The organic solvent used in the temperature gradient cross chromatography test is trichlorobenzene.

3. The propylene-based copolymer according to claim 1 or 2, characterized in that The molecular weight distribution of the propylene-based copolymer is 2.0-4.0; Preferably, the propylene-based 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 to 3, characterized in that The propylene-based copolymer is a copolymer of propylene and a first olefin, wherein the first olefin includes any one of ethylene and C4-C20 α-olefins or a combination of at least two thereof; Preferably, the first olefin comprises any one of ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, and 1-dodecene, or a combination of at least two thereof; Preferably, the mass percentage of the structural unit based on the first olefin in the propylene-based copolymer is 5-20%.

5. A method for preparing a propylene-based copolymer according to any one of claims 1 to 4, characterized in that: The preparation method comprises: propylene and a first olefin are polymerized under the catalysis of a catalyst to obtain the propylene-based copolymer.

6. The preparation method according to claim 5, characterized in that: The catalyst includes a main catalyst, and the main catalyst includes at least one of a transition metal compound with a structure shown in Formula I and a metallocene compound with a structure shown in Formula II: Among them, R1-R 16 Each is independently selected from any one of hydrogen, C1-C30 straight 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 Group IVB metals; X1 and X2 are each independently selected from any one of halogen, C1-C10 straight 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 or branched alkylene and C3-C10 cycloalkylene; 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 or branched alkyl, and substituted or unsubstituted C3-C30 cycloalkyl; 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 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 ring 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 a substituted or unsubstituted C1-C30 straight or branched alkyl group, a substituted or unsubstituted C6-C30 aryl group, and a substituted or unsubstituted C3-C30 heteroaryl group; M2 is selected from any one of Group IVB metals; X3 and X4 are each independently selected from any one of halogen, amino, substituted or unsubstituted C1-C30 straight 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 substituted substituents are each independently selected from at least one of halogen, amino, C1-C10 straight or branched alkyl, C3-C10 cycloalkyl, silane, C6-C30 aryl, and C3-C30 heteroaryl.

7. The preparation method according to claim 5 or 6, characterized in that: The catalyst also includes a co-catalyst, which includes any one or a combination of at least two of the compound of formula III, the compound of formula IV, the compound of formula V, and the compound of formula VI; Among them, R 31 , R 31 , R 33 Each is independently selected from any one of hydrogen, halogen, C1-C30 hydrocarbon group, and halogen-substituted C1-C30 hydrocarbon group; n is an integer ≥ 2; Wherein, Z is aluminum or boron; R 41 , R 41 , R 43 Each is independently selected from any one of halogen, C1-C30 hydrocarbon group, and halogen-substituted C1-C30 hydrocarbon group; [L-H] + [Z(A)4] - Formula V; [L] + [Z(A)4] - Formula VI; Wherein, L represents a neutral Lewis base or a cationic Lewis base; Z is selected from any one of the elements of Group 13; A is independently selected from any one of substituted or unsubstituted C1-C30 hydrocarbon groups and substituted or unsubstituted C1-C30 hydrocarbonoxy groups; the substituents in A are independently selected from at least one of halogen, C1-C30 hydrocarbonoxy groups and C1-C30 hydrocarbon silyl groups.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The polymerization device comprises a tank reactor or a circulating loop reactor; Preferably, the tank reactor is a single reactor or a plurality of reactors connected in series, and the length-to-diameter ratio of the reactor is (5-10):1; Preferably, the circulation ratio of the circulating loop reactor is 1-1000; Preferably, the polymerization reaction is carried out in the presence of a solvent; Preferably, the polymerization reaction temperature is 50-200°C, more preferably 80-180°C; Preferably, the polymerization reaction pressure is 0.1-10 MPa, more preferably 1-5 MPa.

9. Use of the propylene-based copolymer according to any one of claims 1 to 4 in polyolefin film materials.

10. A polyolefin film, characterized in that: The polyolefin film comprises the propylene-based copolymer according to any one of claims 1 to 4; Preferably, the polyolefin film is a polypropylene film, more preferably a cast polypropylene film; Preferably, the polyolefin film comprises a heat-sealing layer, and the heat-sealing layer comprises the propylene-based copolymer according to any one of claims 1 to 4; Preferably, the mass percentage of the propylene-based copolymer in the heat-sealing layer is 1-50%, more preferably 5-30%.

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