Long-chain branched polypropylene and preparation method thereof

Abstract

The present invention relates to the field of polypropylene, and discloses a long-chain branched polypropylene and a preparation method thereof. The long-chain branched polypropylene resin has a structure shown in the following formula (I), and the molar percentage of Si atoms in the long-chain branched polypropylene resin is 0.0001‰-1.25‰, wherein k is an integer of 0-18, m is an integer of 250-25000, n is between 1-5, x is an integer greater than 1, and R is a linear, branched or isomerized alkyl group having a carbon number of 1-20. The long-chain branched polypropylene resin of the present invention has the effects of high comonomer insertion efficiency, clear polymer structure, and uniform distribution of long-chain branched structures in the polymer chain.

Description

Technical Field

[0001] The invention relates to the field of polypropylene, and in particular to a long-chain branched polypropylene and a preparation method thereof. Background Art

[0002] As a thermoplastic polymer material with excellent performance, polypropylene has the characteristics of low density, excellent mechanical properties, temperature and corrosion resistance, non-toxicity, and easy processing and molding. It is widely used in various fields of daily life such as automobiles, household appliances, food packaging, and building materials.

[0003] Since the 1980s, metallocene catalysts have entered a rapid development stage, and a variety of polyolefin products based on metallocene catalysts have been developed. Different from traditional Ziegler-Natta catalysts, metallocene catalysts have the following characteristics: 1) Metallocene catalysts can control the structure of the catalyst by modifying the catalyst ligand to achieve control of the microstructure of the polyolefin product, and can also control the molecular weight, molecular weight distribution, comonomer content and stereoregularity of the obtained polymer by screening appropriate reaction conditions; 2) The catalyst has extremely high catalytic activity, which is 10-100 times that of traditional Ziegler-Natta catalysts; 3) Metallocene catalysts have excellent copolymerization properties. In addition to common α-olefins, the olefin monomers commonly used by metallocene catalysts are also suitable for copolymerization reactions of high-carbon α-olefins and bicyclic or polycyclic olefins; 4) Metallocene catalysts are single-active center catalysts, and the prepared polyolefins have a narrow molecular weight distribution and a uniform intermolecular microstructure. Although metallocene catalysts have excellent control capabilities in terms of polymer molecular chain structure, the polyolefin resins obtained by metallocene catalysts have the characteristics of narrow molecular weight distribution, resulting in poor melt processing performance. In order to improve its melt processing performance, the use of multi-reactor method to increase molecular weight distribution and long chain branching are two effective ways. Among them, the long chain branch structure can make the polymer melt have shear thinning phenomenon, significantly improve the melt processing performance of polypropylene, and can also improve the melt strength of polypropylene, further improve its melt processing performance, solve the edge curling and shrinkage during high-speed extrusion coating, the collapse of the bubble during extrusion foaming, the occurrence of sag during thermoforming and the uneven thickness of the product, and expand the application of polypropylene in the above fields.

[0004] Generally, there are two main ways to prepare long-chain branched polypropylene, namely, post-polymerization modification and reactor direct polymerization. The post-polymerization reaction modification method mainly obtains polypropylene with a long-chain branched structure by means of high-energy ray radiation, free radical grafting, etc., which utilizes free radical reactions, so degradation and cross-linking reactions of polypropylene are inevitable, and the production cost is high. The reactor method is to directly prepare long-chain branched polypropylene by regulating the polymerization reaction in a polymerization kettle. So far, the work of preparing long-chain branched polypropylene by the reactor method is mostly based on metallocene and non-metallocene catalyst systems. For example, two or more metallocene catalysts or non-metallocene catalysts are selected in a single reactor or multiple reactors, and firstly polymerize to generate macromonomers (with a longer molecular weight and a reactive double bond at the end), and then the macromonomers are copolymerized with propylene in situ to realize the long-chain branching of polypropylene (GW Coates, et al. Macromolecules 2005, 38, 6259). However, this method has the problem that the residual reactive macromonomers cannot be removed and affect the final performance of the polymer, which is difficult to solve. The method of directly preparing long-chain branched polypropylene in a reactor that is currently widely used is to add α,ω-non-conjugated dienes as comonomers during the propylene polymerization process, and to generate long-chain branched structures in situ through the participation of the α and ω olefin double bonds in the polymerization of different polymer chains. (Shiping Zhu, et al. Macromol. React. Eng., 2016, 10, 156; Rytter E, et al. Polymer, 2007, 48, 2793; EP0942017A2; EP1242483B1; US6809168; US7005491). This method has high requirements for the catalyst structure and the α,ω-non-conjugated diene structure, requiring the catalyst to have a high copolymerization ability, and the α,ω-non-conjugated diene needs to have a certain chain length to inhibit the occurrence of intramolecular cyclization reactions. At present, except for α,ω-non-conjugated dienes, there are no other comonomers that allow the preparation of long-chain branched polypropylene based on metallocene catalysts and reactor direct polymerization methods. Earlier, the Institute of Chemistry, Chinese Academy of Sciences, based on the ZieglerNatta catalyst system, used ω-olefin methyldichlorosilane as a comonomer to prepare polypropylene with a long-chain branched structure (Jin-Yong Dong, et al. Ind. Eng. Chem. Res. 2021, 60, 4589; Jin-Yong Dong, et al. Polymer, 2020, 202, 122737; CN10656883A; W02017063116A1; EP3363822A1; JP2018-530659A; US10934373B2).However, since the Ziegler-Natta catalyst is insensitive to large steric monomers and has multiple active centers, the insertion efficiency of the ω-olefin methyldichlorosilane co-monomer is low, the polymer structure is complex, the long-chain branched structure is unevenly distributed in the polymer chain, and the influence of the long-chain branched structure on the rheological properties of the polymer melt cannot be fully reflected. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems in the prior art that the ω-olefin methyl dichlorosilane comonomer insertion efficiency is low, the polymer structure is complex, the long-chain branched structure is unevenly distributed in the polymer chain, and the influence of the long-chain branched structure on the rheological properties of the polymer melt cannot be fully reflected. A novel long-chain branched polypropylene resin based on a metallocene catalyst system and a preparation method thereof are provided. The novel long-chain branched polypropylene resin has the effects of high comonomer insertion efficiency, clear polymer structure, and uniform distribution of the long-chain branched structure in the polymer chain.

[0006] In order to achieve the above object, the present invention provides a long-chain branched polypropylene on one hand, wherein the long-chain branched polypropylene resin has a structure shown in the following formula (I), and the molar percentage of Si atoms in the long-chain branched polypropylene resin is 0.0001‰-1.25‰,

[0007]

[0008] In formula (I), k is an integer of 0-18, m is an integer of 250-25000, n is between 1-5, x is an integer greater than 1, and R is a linear, branched or isomerized alkyl group having 1-20 carbon atoms.

[0009] Preferably, the long-chain branched polypropylene has a gel content of 0-1 wt%.

[0010] Preferably, the molecular weight distribution of the long-chain branched polypropylene is less than 3.

[0011] Preferably, the weight average molecular weight of the long-chain branched polypropylene is 1×10 4 -2×10 6 g / mol.

[0012] Preferably, the long-chain branched polypropylene is prepared using a metallocene catalyst.

[0013] According to a second aspect of the present invention, there is provided a long-chain branched polypropylene, wherein the long-chain branched polypropylene resin has a structure represented by the following formula (II), and the molar percentage of Si atoms is 0.0001‰-1.25‰,

[0014]

[0015] In formula (II), k is an integer of 0-18, m is an integer of 250-50000, n is between 1-5, o is an integer of 0-50000, x is an integer greater than 1, R1 is a straight chain, branched or isomerized alkyl group having 1-20 carbon atoms, and R2 is a hydrogen atom or a straight chain alkyl group having 2-7 carbon atoms.

[0016] Preferably, the long-chain branched polypropylene has a gel content of 0-1 wt%.

[0017] Preferably, the molecular weight distribution of the long-chain branched polypropylene is less than 3.

[0018] Preferably, the weight average molecular weight of the long-chain branched polypropylene is 1×10 4 -2×10 6 g / mol.

[0019] Preferably, the long-chain branched polypropylene is prepared using a metallocene catalyst.

[0020] According to a third aspect of the present invention, there is provided a method for preparing long-chain branched polypropylene, wherein the method comprises the steps of polymerizing propylene, optional α-olefin and ω-olefin-based dichlorosilane in the presence of a metallocene catalyst, and subjecting the polymer to hydrolysis and condensation through Si-Cl bonds.

[0021] Preferably, the ω-olefin dichlorosilane is selected from the general formula R 1 SiCl2R 2 At least one of the compounds of the structure shown in the general formula, wherein R 1 is an olefin group having 2 to 20 carbon atoms and an olefin double bond at the end, R 2 The number of carbon atoms is 1-20 More preferably, the ω-olefin disiloxane is at least one of 11-dodecenylmethyldichlorosilane, 11-dodecenylethyldichlorosilane, 11-dodecenylisopropyldichlorosilane, 9-decenylmethyldichlorosilane, 9-decenylbutyldichlorosilane, 9-decenylhexyldichlorosilane, 7-octenylethyldichlorosilane, 7-octenylmethyldichlorosilane, 7-octenyloctyldichlorosilane, 5-hexenylisopropyldichlorosilane, 5-hexenylmethyldichlorosilane, 5-hexenylethyldichlorosilane, 4-pentenylbutyldichlorosilane, 4-pentenylmethyldichlorosilane, 4-pentenylethyldichlorosilane, 3-butenylisopropyldichlorosilane, 3-butenylmethyldichlorosilane and 3-butenylethyldichlorosilane.

[0022] Preferably, the metallocene catalyst is a catalyst having Cp m R n MX qThe invention relates to a metal organic compound of a structure wherein Cp is independently substituted or unsubstituted cyclopentadienyl and its derivatives; M is a transition metal of Groups 4, 5 and 6; R is a structural bridge providing stereorigidity between two Cp groups; X is a halogen or a hydrocarbon group having 1 to 20 carbon atoms; and m=1-2, n=0-1, q=2-3, and the sum of m+q is equal to the oxidation state of the transition metal.

[0023] Preferably, the polymerization is carried out in the presence of a cocatalyst selected from alkylaluminoxane compounds or organic boron compounds.

[0024] Preferably, for alkylaluminoxane compounds, the amount of the co-catalyst added is calculated as the molar ratio of Al to the transition metal M in the main catalyst, which is Al:M=10-50000:1, preferably 100-5000:1; for organic boride, the amount of the co-catalyst added is calculated as the molar ratio of B to the transition metal M in the main catalyst, which is B:M=0.1-100:1, preferably 0.5-10:1.

[0025] Preferably, the weight ratio of propylene to ω-olefin dichlorosilane is 0.001‰-5.0‰:1.

[0026] Preferably, the weight ratio of the catalyst to the polymerization monomer calculated as the transition metal M is 0.01‰-5.0‰:1.

[0027] Preferably, the α-olefin is at least one of ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-nonene.

[0028] Preferably, the amount of propylene used is such that the content of propylene units in the long-chain branched polypropylene is 80-99.8 wt %, and the content of α-olefin units is 0.1-10 wt %.

[0029] Preferably, the method of hydrolyzing and condensing the polymer via Si—Cl bonds comprises: contacting the polymer with water.

[0030] According to a fourth aspect of the present invention, there is provided a long-chain branched polypropylene prepared by the method of the present invention.

[0031] Through the above technical scheme, the novel long-chain branched polypropylene resin of the present invention has the effects of high comonomer insertion efficiency, narrow molecular weight distribution, clear polymer structure, uniform distribution of long-chain branched structure in the polymer chain and controllable density.

[0032] In addition, the long-chain branched polypropylene of the present invention has a uniform long-chain branched structure, which can effectively improve the melt processing performance of the polymer and effectively solve the problems of edge curling and shrinkage during high-speed extrusion coating, cell collapse during extrusion foaming, sag during thermoforming, and uneven thickness of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The long-chain branched polypropylene of Example 1 1 H-NMR spectrum.

[0034] Figure 2 It is a comparison chart of the rheological properties of the long-chain branched polypropylene of Example 2 and the linear polypropylene of Comparative Example 2.

[0035] Figure 3 This is a graph showing the strain hardening phenomenon exhibited in the extensional rheology test of the long-chain branched polypropylene of Example 3. DETAILED DESCRIPTION

[0036] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0037] According to a first aspect of the present invention, a long-chain branched polypropylene is provided, wherein the long-chain branched polypropylene resin has a structure represented by the following formula (I), and the molar percentage of Si atoms in the long-chain branched polypropylene resin is 0.0001‰-1.25‰,

[0038]

[0039] In formula (I), k is an integer of 0-18, m is an integer of 250-25000, n is between 1-5, x is an integer greater than 1, and R is a linear, branched or isomerized alkyl group having 1-20 carbon atoms.

[0040] Preferably, k is 2-10.

[0041] Specific examples of K include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, and 18.

[0042] Preferably, m is 2500-15000.

[0043] Specific examples of m include 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200, 4400, 4400, 4500, 4600, 4700, 4800, 4900, 5000, 6000, 7000, 8000, 9000, 10000, 11000, 12000, 13000, 14000, and 15000.

[0044] Preferably, n is 1-2.

[0045] Specific examples of n include 1, 2, 3, 4, and 5.

[0046] Preferably, x is 1-20, more preferably 1-10, further preferably 1-5.

[0047] Specific examples of x include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20.

[0048] Preferably, R is a linear, branched or isomerized alkyl group having 1 to 12 carbon atoms.

[0049] In the present invention, examples of the linear, branched or isomerized alkyl group having 1 to 20 carbon atoms include isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, isohexyl, isoheptyl, 2-methylhexyl, 2-ethylhexyl, 1-methylheptyl, 2-methylheptyl, isooctyl, isononyl, 3,5,5-trimethylhexyl, 2,6-dimethyl-4-heptyl, isodecyl, isoundecyl, isododecyl, isotridecyl, isotetradecyl, isopentadecyl, isohexadecyl, isoheptadecyl, isooctadecyl, isononadecyl, isoeicosyl, methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl and n-oeicosyl.

[0050] According to the present invention, the above k, m, n and x can be selected within the above range. Preferably, the above k, m, n and x are selected so that the weight average molecular weight of the long-chain branched polypropylene is 1×10 5 -1×10 6 g / mol; More preferably, the values ​​of k, m, n and x are such that the weight average molecular weight of the long-chain branched polypropylene is 2×10 5 -8.5×10 5g / mol.

[0051] Preferably, the molar percentage of Si atoms in the long-chain branched polypropylene resin is 0.001‰-0.8‰, more preferably 0.01‰-0.5‰, further preferably 0.02‰-0.3‰, and further preferably 0.05‰-0.2‰.

[0052] According to the present invention, due to the uniform distribution of the long-chain branched structure in the polymer, the gel content of the long-chain branched polypropylene of the present invention is very low. Preferably, the gel content of the long-chain branched polypropylene is less than 1.0 wt%. More preferably, the gel content of the long-chain branched polypropylene is 0-0.1 wt%. Particularly preferably, the gel content of the long-chain branched polypropylene is 0 wt%.

[0053] According to the present invention, preferably, the molecular weight distribution of the long-chain branched polypropylene is less than 3.

[0054] According to the present invention, preferably, the weight average molecular weight of the long-chain branched polypropylene is 1×10 5 -1×10 6 g / mol; More preferably, the weight average molecular weight of the long-chain branched polypropylene is 2×10 5 -8.5×10 5 g / mol.

[0055] According to the present invention, preferably, the long-chain branched polypropylene is H-type long-chain branched polypropylene.

[0056] According to the present invention, the long-chain branched polypropylene is prepared using a metallocene catalyst as a catalyst.

[0057] According to a second aspect of the present invention, there is provided a long-chain branched polypropylene, wherein the long-chain branched polypropylene resin has a structure represented by the following formula (II), and the molar percentage of Si atoms is 0.0001‰-1.25‰,

[0058]

[0059] In formula (II), k is an integer of 0-18, m is an integer of 250-50000, n is between 1-5, o is an integer of 0-50000, x is an integer greater than 1, R1 is a straight chain, branched or isomerized alkyl group having 1-20 carbon atoms, and R2 is a hydrogen atom or a straight chain alkyl group having 2-7 carbon atoms.

[0060] Preferably, k is 2-10.

[0061] Specific examples of K include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, and 18.

[0062] Preferably, m is 2500-15000.

[0063] Specific examples of m include 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200, 4400, 4400, 4500, 4600, 4700, 4800, 4900, 5000, 6000, 7000, 8000, 9000, 10000, 11000, 12000, 13000, 14000, and 15000.

[0064] Preferably, n is 1-2.

[0065] Specific examples of n include 1, 2, 3, 4, and 5.

[0066] Preferably, o is 1-100% of m.

[0067] Specific examples of o include 25, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400, 3500, 3600、3700、3800、3900、4000、4100、4200、4400、4400、4500、4600、4700、4800、 4900、5000、6000、7000、8000、9000、10000、11000、12000、13000、14000、15000 etc.

[0068] Preferably, x is 1-20.

[0069] Specific examples of x include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20.

[0070] Preferably, R1 is a linear, branched or isomerized alkyl group having 1 to 12 carbon atoms.

[0071] In the present invention, the linear, branched or isomerized alkyl group having 1 to 20 carbon atoms is as described above.

[0072] Examples of the linear alkyl group having 2 to 7 carbon atoms include ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, and n-heptyl.

[0073] According to the present invention, the above k, m, n, o and x can be selected within the above range. Preferably, the above k, m, n, o and x are selected so that the weight average molecular weight of the long-chain branched polypropylene is 1×10 5 -1×10 6 g / mol; More preferably, the values ​​of k, m, n, o and x are such that the weight average molecular weight of the long-chain branched polypropylene is 2×10 5 -8.5×10 5 g / mol; More preferably, the values ​​of k, m, n, o and x are such that the weight average molecular weight of the long-chain branched polypropylene is 3×10 5 -5×10 5 g / mol; More preferably, the values ​​of k, m, n, o and x are such that the weight average molecular weight of the long-chain branched polypropylene is 3×10 5 -4×10 5 g / mol.

[0074] Preferably, the molar percentage of Si atoms in the long-chain branched polypropylene resin is 0.001-0.8‰, more preferably 0.01‰-0.5‰, further preferably 0.02‰-0.3‰, further preferably 0.05‰-0.2‰, further preferably 0.05‰-0.1‰, further preferably 0.05‰-0.09‰, further preferably 0.05‰-0.07‰.

[0075] According to the present invention, due to the uniform distribution of the long-chain branched structure in the polymer, the gel content of the long-chain branched polypropylene of the present invention is very low. Preferably, the gel content of the long-chain branched polypropylene is less than 1.0 wt%. More preferably, the gel content of the long-chain branched polypropylene is 0-0.1 wt%. Particularly preferably, the gel content of the long-chain branched polypropylene is 0 wt%.

[0076] According to the present invention, preferably, the molecular weight distribution of the long-chain branched polypropylene is less than 3.

[0077] According to the present invention, preferably, the weight average molecular weight of the long-chain branched polypropylene is 1×10 5 -1×10 6 g / mol; More preferably, the weight average molecular weight of the long-chain branched polypropylene is 2×10 5 -8×105 g / mol; more preferably, the weight average molecular weight of the long-chain branched polypropylene is 3×10 5 -5×10 5 g / mol; more preferably, the weight average molecular weight of the long-chain branched polypropylene is 3×10 5 -4×10 5 g / mol.

[0078] According to the present invention, preferably, the long-chain branched polypropylene is H-type long-chain branched polypropylene.

[0079] According to the present invention, the long-chain branched polypropylene is prepared using a metallocene catalyst as a catalyst.

[0080] According to a third aspect of the present invention, there is provided a method for preparing long-chain branched polypropylene, wherein the method comprises the steps of polymerizing propylene, optional α-olefin and ω-olefin-based dichlorosilane in the presence of a metallocene catalyst, and subjecting the polymer to hydrolysis and condensation through Si-Cl bonds.

[0081] According to the method of the present invention, preferably, the ω-olefin dichlorosilane is selected from the general formula R 1 SiCl2R 2 At least one of the compounds of the structure shown in the general formula, wherein R 1 is an olefin group having 2 to 20 carbon atoms and an olefin double bond at the end, R 2 is a linear, branched or isomerized alkyl group having 1 to 20 carbon atoms. More preferably, in the general formula, R 1 is an olefin group having 4 to 12 carbon atoms and an olefin double bond at the end, R 2 It is a straight chain, branched chain or isomerized alkyl group having 1 to 12 carbon atoms.

[0082] Preferably, the ω-olefin disiloxane is at least one of 11-dodecenylmethyldichlorosilane, 11-dodecenylethyldichlorosilane, 11-dodecenylisopropyldichlorosilane, 9-decenylmethyldichlorosilane, 9-decenylbutyldichlorosilane, 9-decenylhexyldichlorosilane, 7-octenylethyldichlorosilane, 7-octenylmethyldichlorosilane, 7-octenyloctyldichlorosilane, 5-hexenylisopropyldichlorosilane, 5-hexenylmethyldichlorosilane, 5-hexenylethyldichlorosilane, 4-pentenylbutyldichlorosilane, 4-pentenylmethyldichlorosilane, 4-pentenylethyldichlorosilane, 3-butenylisopropyldichlorosilane, 3-butenylmethyldichlorosilane and 3-butenylethyldichlorosilane.

[0083] According to the method of the present invention, the metallocene catalyst generally refers to a catalyst having a Cp m R n MXq The metal organic compound of the structure, wherein Cp is independently substituted or unsubstituted cyclopentadienyl and its derivatives (such as indenyl and fluorenyl), wherein the substituents on the Cp derivatives are independently selected from hydrogen, C1-C 10 The cycloalkyl group may have a C1-C6 alkyl group as a substituent, and the C6-C 15 aryl or aralkyl, wherein two adjacent groups can further form an unsaturated ring of 4-15 carbon atoms, or Si(R)3, R is C1-C 10 Alkyl, C6-C 15 Aryl or C3-C 10 The cycloalkyl group is a cycloalkyl group such as Ph, Bz, Naph, BzInd, Me, Et, n-Pr, iso-Pr, n-Bu and tert-Bu, but is not limited to these structures; M is a transition metal of Groups 4, 5 and 6, such as titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten; R is a structural bridge that provides stereorigidity between two Cp groups; X is a halogen or a hydrocarbon group having 1-20 carbon atoms; and m=1-2, n=0-1, q=2-3, and the sum of m+q is equal to the oxidation state of the transition metal. Methods for preparing and using metallocenes are well known in the art.

[0084] The metallocene catalyst can be either supported or unsupported. The supported type is a metallocene supported on a porous inorganic carrier treated with an alkylaluminoxane. Examples of suitable carriers are: magnesium halide, silicon dioxide, aluminum oxide, aluminum silicate or a mixture thereof. The supported metallocene catalyst used is usually dispersed in an inert solvent, which can be: an aliphatic hydrocarbon solvent, such as hexane, heptane, cyclohexane; an aromatic hydrocarbon solvent, such as benzene, toluene, xylene; a halogenated hydrocarbon solvent, such as dichloromethane, chloroform. In the supported metallocene catalyst, the weight content of aluminum is 1-50%, preferably 1-15%; the weight content of the central metal M is 0.01-5%, preferably 0.05-2%.

[0085] The metallocene catalyst, preferably the metallocene catalyst system comprises the following active ingredients:

[0086]

[0087] wherein M is a metal of Groups 4, 5 and 6 of the Periodic Table of Elements, such as titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten, preferably titanium, zirconium and hafnium; R 1 and R 2 are independently a halogen atom (fluorine, chlorine, bromine, iodine), hydrogen, C1-C 10 Alkyl, C6-C 15 Aryl or -OR 18 , R18 It is C1-C 10 Alkyl, C6-C 15 Aryl, alkylaryl, arylalkyl, halogenated alkyl or halogenated aryl, wherein the alkyl group contains 1 to 10 carbon atoms and the aryl group contains 6 to 20 carbon atoms; R 3 To R 6 Each is independently a hydrogen atom, a halogen atom (fluorine, chlorine, bromine, iodine), a C1-C 10 Alkyl groups, which may be halogenated C6-C 15 Aryl, C2-C 10 Alkenyl, C7-C 40 Arylalkyl, C7-C 40 Alkyl, C8-C 40 Arylalkenyl, -NR 19 , -SR 19 , -OR 19 , -OSiR 19 or-PR2 19 Group (where R 19 is a halogen atom, C1-C 10 Alkyl, C6-C 15 Aryl) and two adjacent groups can be combined together to form a ring system; R 7 for =BR 11 , =AlR 11 , -Ge-, -Sn-, -O-, -S-, =SO, =SO2, =NR 11 , =CO, =PR 11 or = P(O)R 11 , where R 11 , R 12 and R 13 Each is independently a hydrogen atom, a halogen atom, a C1-C 20 Alkyl, C1-C 20 haloalkyl, C6-C 30 Aryl, C6-C 20 The halogenated aryl group, C1-C 10 Alkoxy, C2-C 20 Alkenyl, C7-C 40 Arylalkyl, C8-C 40 Arylalkenyl, C7-C 40 The alkylaryl group, or R 11 and R 12 or R 11 and R 13 They can form a switching system together with the atoms that bond them; Q is silicon, germanium or tin; R 8 and R9 Each independently has a 11 The meanings given above; m and n are the same or different and are 0, 1 or 2; the group R 10 Each is independent and has its own 11 , R 12 and R 13 The meaning of two adjacent R 10 The groups can be combined together to form ring systems.

[0088] Illustrative but non-limiting examples of the metallocene catalysts include: ethylbis(1-indenyl)titanium dichloride, ethylbis(1-indenyl)zirconium dichloride, dimethylsilylbis(1-indenyl)zirconium dichloride, dimethylsilylbis(1-indenyl)hafnium dichloride, dimethylsilylbis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, dimethylsilylbis(2-methyl-4,5-benzoindenyl)titanium dichloride, dimethylsilylbis(2-methyl-4,5-benzoindenyl)zirconium dichloride, dimethylsilylbis(2-methyl-4,5-benzoindenyl) Silylbis(2-methyl-4,6-diisopropylindenyl)zirconium dichloride, dimethylsilylbis(2-ethyl-4-phenyl-1-indenyl)hafnium dichloride, dimethylsilylbis(2-ethyl-4-naphthyl-1-indenyl)zirconium dichloride, phenyl(methyl)silylbis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, phenyl(methyl)silylbis(2-methyl-4-phenyl-1-indenyl)titanium dichloride, dimethylsilylbis(2-methyl-4-(1-naphthyl)-1-indenyl) Hafnium dichloride, dimethylsilylbis(2-methyl-4-(2-naphthyl)-1-indenyl)zirconium dichloride, dimethylsilylbis(2-methyl-indenyl)zirconium dichloride, dimethylsilylbis(2-methyl-4,5-diisopropyl-1-indenyl)zirconium dichloride, dimethylsilylbis(2,4,6-trimethyl-1-indenyl)zirconium dichloride, phenyl(methyl)silylbis(2-methyl-4,6-diisopropyl-1-indenyl)titanium dichloride, 1,2-ethanediylbis(2-methyl-4,6-diisopropyl-1-indenyl)zirconium dichloride, 1,2-butanediylbis(2-methyl-4,6- Diisopropyl-1-indenyl) zirconium dichloride, dimethylsilylbis(2-methyl-4-ethyl-1-indenyl) hafnium dichloride, dimethylsilylbis(2-methyl-4-isopropyl-1-indenyl) titanium dichloride, dimethylsilylbis(2-methyl-4-tert-butyl-1-indenyl) zirconium dichloride, phenyl(methyl)silylbis(2-methyl-4-isopropyl-1-indenyl) hafnium dichloride, dimethylsilylbis(2-ethyl-4-methyl-1-indenyl) zirconium dichloride, dimethylsilylbis(2,4-dimethyl-1-indenyl) zirconium dichloride, dimethylsilylbis(2-methyl-4-tert-butyl-1-indenyl) zirconium dichloride 1,2-Ethanediylbis(2-methyl-4,5-benzo-1-indenyl)zirconium dichloride, 1,2-Butanediylbis(2-methyl-4,5-benzo-1-indenyl)zirconium dichloride, 1,2-Butanediylbis(2-methyl-4,5-benzo-1-indenyl)zirconium dichloride, 1,2-Dimethylsilylbis(2-methyl-4,5-(tetramethylbenzo)-1-indenyl)hafnium dichloride, 1,2-Ethanediylbis(2-methyl-4,5-benzo-1-indenyl)zirconium dichloride, 1,2-Butanediylbis(2-methyl-4,5-benzo-1-indenyl)zirconium dichloride, 1,2-Dimethylsilylbis(2-methyl-4,5-(tetramethylbenzo)-1-indenyl)zirconium dichloride, 1,2-Dimethylsilylbis(2-methyl-4,5-(tetramethylbenzo)-1-indenyl)5-benzo-1-indenyl) titanium dichloride, 1,2-ethanediylbis(2,4,7-trimethyl-1-indenyl)titanium dichloride, dimethylsilylbis(2-methyl-1-indenyl)hafnium dichloride, 1,2-ethanediylbis(2-methyl-1-indenyl)hafnium dichloride, phenyl(methyl)silylbis(2-methyl-1- Indenyl) titanium dichloride, diphenylsilyl bis (2-methyl-1-indenyl) zirconium dichloride, 1,2-butanediyl bis (2-methyl-1-indenyl) zirconium dichloride, dimethylsilyl bis (2-ethyl-1-indenyl) zirconium dichloride, dimethylsilyl bis (2-methyl-5-isobutyl-1-indenyl) titanium dichloride, phenyl (methyl) silyl bis (2-methyl-5-isobutyl-1-indenyl) zirconium dichloride, dimethylsilyl Bis(2-methyl-5-tert-butyl-1-indenyl) hafnium dichloride, dimethylsilylbis(2,5,6-trimethyl-1-indenyl) zirconium dichloride, dibenzylidene(3,5-dimethylcyclopentadienyl)(fluorenyl) zirconium dichloride, dibenzylidene(3,5-dimethylcyclopentadienyl)(2,7-di-tert-butylfluorenyl) hafnium dichloride, dibenzylidene(3,5-dimethylcyclopentadienyl)(3,6-di-tert-butylfluorenyl) Zirconium dioxide, benzhydrylidene (3,5-dimethylcyclopentadienyl (octamethyl octahydrodibenzofluorenyl) zirconium dichloride, benzhydrylidene (3-tert-butyl-5-methyl-cyclopentadienyl) (fluorenyl) hafnium dichloride, benzhydrylidene (3-tert-butyl-5-methyl-cyclopentadienyl) (2,7-di-tert-butylfluorenyl) titanium dichloride, benzhydrylidene (3-tert-butyl-5-methyl-cyclopentadienyl) (3,6-di- tert-butylfluorenyl)zirconium dichloride, benzhydrylidene (3-tert-butyl-5-methyl-cyclopentadienyl) (octamethyloctahydrodibenzofluorenyl) hafnium dichloride, benzhydrylidene (3-(2-adamantyl)-5-methyl-cyclopentadienyl) (fluorenyl) zirconium dichloride, benzhydrylidene (3-(2-adamantyl)-5-methyl-cyclopentadienyl) (2,7-di-tert-butylfluorenyl) zirconium dichloride, benzhydrylidene (3-(2-adamantyl)-5-methyl-cyclopentadienyl) (3,6-di-tert-butylfluorenyl) zirconium dichloride, benzhydrylidene (3-(2-adamantyl)-5-methyl-cyclopentadienyl) ( methylcyclopentadienyl)(octamethyloctahydrodibenzofluorenyl)zirconium dichloride, benzhydrylidene(3-tert-butyl-5-ethyl-cyclopentadienyl)(fluorenyl)zirconium dichloride, benzhydrylidene(3-tert-butyl-5-ethyl-cyclopentadienyl)(2,7-di-tert-butylfluorenyl)hafnium dichloride, benzhydrylidene(3-tert-butyl-5-ethyl-cyclopentadienyl)(3,6-di-tert-butyl)zirconium dichloride, benzhydrylidene(3-tert-butyl--ethyl-cyclopentadienyl)(octamethyloctahydrodibenzofluorenyl)zirconium dichloride, benzhydrylidene(3-tert-butyl-2,5-dimethyl-cyclopentadienyl)(fluorenyl)zirconium dichloride, benzhydrylidene(3-tert-butyl-2,5-dimethyl-cyclopentadienyl)(fluorenyl)zirconium dichloride,7-di-tert-butylfluorenyl) zirconium dichloride, dibenzhydryl (3-tert-butyl-2,5-dimethyl-cyclopentadienyl) (3,6-di-tert-butylfluorenyl) zirconium dichloride, dibenzhydryl (3-tert-butyl-2,5-dimethyl-cyclopentadienyl) (octamethyl octahydrodibenzofluorenyl) zirconium dichloride, di(p-tolyl) methylene (3,5-dimethylcyclopentadienyl) (fluorenyl) zirconium dichloride, di(p-tolyl) methylene (3,5-dimethylcyclopentadienyl) (2,7-di-tert-butylfluorenyl) zirconium dichloride, etc.

[0089] According to the method of the present invention, the preparation of the metallocene catalyst used in the polymerization process refers to relevant patents and documents: US5149819; US5243001; US5239022; US5296434; US5276208; CN1309669A; Zhuhongping, et al. Chin. J. Org. Chem. 2018, 38, 2937; Luigi Resconi, et al. Chem. Rev. 2000, 100, 1253.

[0090] According to the process of the present invention, preferably, the polymerization is carried out in the presence of a co-catalyst, which is defined herein as a compound or component capable of activating the metallocene catalyst as described above.

[0091] According to the method of the present invention, preferably, the co-catalyst is selected from alkylaluminoxane compounds or organic boron compounds.

[0092] The above-mentioned alkylaluminoxane is preferably methylaluminoxane, modified methylaluminoxane (including modified methylaluminoxane obtained by replacing part of the methyl groups in methylaluminoxane with ethyl and / or isobutyl groups; modified methylaluminoxane prepared using boron compounds, silyl ethers and polar organic substances containing P, N, S or O), ethylaluminoxane, isobutylaluminoxane, tert-butylaluminoxane, etc.

[0093] The organic boron compound is selected from B(C6F5)3, [CPh3] + [B(C6F5)4] - and [PhNH(Me)2] + [B(C6F5)4] - At least one of .

[0094] According to the method of the present invention, for alkylaluminoxane compounds, the amount of the co-catalyst added is calculated based on the molar ratio of Al to the transition metal M in the main catalyst, which is Al:M=10-50000:1, preferably 100-5000:1; for organic boride, the amount of the co-catalyst added is calculated based on the molar ratio of B to the transition metal M in the main catalyst, which is B:M=0.1-100:1, preferably 0.5-10:1.

[0095] According to the method of the present invention, preferably, the weight ratio of propylene to ω-olefin dichlorosilane is 0.001‰-5.0‰:1; more preferably, the weight ratio of propylene to ω-olefin dichlorosilane is 0.01‰-1.0‰:1.

[0096] According to the present invention, preferably, the weight ratio of the catalyst calculated as transition metal M to the polymerization monomer is 0.01‰-5.0‰:1; more preferably, the weight ratio of the catalyst calculated as transition metal M to the polymerization monomer is 0.01‰-1.0‰:1.

[0097] According to the method of the present invention, when the α-olefin is used, the long-chain branched polypropylene also includes random copolymerized polypropylene, wherein the comonomer α-olefin is preferably at least one of ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-nonene.

[0098] At this time, the amount of the monomers can vary in a wide range. Preferably, the amount of propylene and the α-olefin is such that the content of propylene units in the long-chain branched polypropylene is 80-99.8 wt %, and the content of the α-olefin units is 0.1-10 wt %.

[0099] According to the method of the present invention, propylene, optional α-olefin and ω-olefin dichlorosilane are polymerized, and then the polymer is hydrolyzed and condensed through Si-Cl bonds. Preferably, the method for hydrolyzing and condensing the polymer through Si-Cl bonds includes: contacting the polymer with water. The water can also be used in liquid and water vapor form. In addition, the amount of water used is excessive, as long as the polymer can be fully hydrolyzed and condensed through Si-Cl bonds.

[0100] According to the present invention, preferably, the polymerization conditions include: polymerization temperature of -50-100°C, polymerization time of 0.05-12 hours, polymerization pressure of 0.01-6Mpa; more preferably, the polymerization conditions include: polymerization temperature of 10-80°C, polymerization time of 0.1-4 hours, polymerization pressure of 0.01-3.5Mpa.

[0101] According to the present invention, preferably, the hydrolysis condensation conditions include: the hydrolysis condensation temperature is 50-120°C, and the hydrolysis condensation time is 0.02-12 hours; more preferably, the polymerization conditions include: the hydrolysis condensation temperature is 70-110°C, and the hydrolysis condensation time is 0.1-2 hours.

[0102] According to the method of the present invention, hydrogen can also be introduced into the polymerization reaction system during the preparation of the polypropylene. If the amount of hydrogen added during the polymerization is too high, the melt strength of the polypropylene will be weakened. The amount of hydrogen added can be selected according to the actual function of the polypropylene to be obtained. For example, the amount of hydrogen added can be 1×10 -4 -0.1 parts by weight, preferably 1×10 -4 -0.05 parts by weight.

[0103] According to the fourth aspect of the present invention, there is also provided a long-chain branched polypropylene prepared by the method for preparing the long-chain branched polypropylene of the present invention.

[0104] The long-chain branched polypropylene of the present invention has a uniform long-chain branched structure, can effectively improve the melt processing performance of the polymer, and effectively solve the problems of edge curling and shrinkage during high-speed extrusion coating, cell collapse during extrusion foaming, sag during thermoforming, and uneven thickness of products.

[0105] The present invention will be described in detail below by way of examples, but the present invention is not limited to the following examples.

[0106] In the following examples and comparative examples, the gel content of long-chain branched polypropylene (including homopolymerized polypropylene and random copolymerized polypropylene) was determined according to the following method:

[0107] The polypropylene was dried in a vacuum drying oven at 50°C to constant weight, weighed, and recorded as W1. The dried polyolefin resin was then dissolved in xylene, shaken at 135°C to fully dissolve, and filtered with a 200-mesh stainless steel mesh to collect the insoluble polymer remaining on the stainless steel mesh. The insoluble polymer on the stainless steel mesh was dried in a vacuum drying oven at 100°C for 4 hours, weighed, and recorded as W2. The formula for calculating the gel content of random copolymer polypropylene is as follows:

[0108] Gel content (weight %) = (W2 / W1) x 100 (weight %).

[0109] The melting temperature of the prepared polypropylene was tested using a differential scanning calorimeter model Q2000 produced by TA Company.

[0110] The storage modulus of the prepared polypropylene at a shear frequency of 0.01 rad / s was tested using an AR2000 parallel plate rheometer produced by TA Corporation of the United States.

[0111] The melt strength of the prepared polypropylene was tested using a Rheotens melt strength tester model 71.97 produced by Goettfert.

[0112] The melt index of the prepared polypropylene was tested using a Haake-SWO melt indexer model 556-0031 produced by Haake Company of Germany.

[0113] The weight average molecular weight of the prepared polypropylene was tested using a PL-220 high temperature gel permeation chromatograph produced by Agilent Technologies, USA.

[0114] The branching structure content of the prepared polypropylene was tested by hydrogen spectrum using Bruker's AVANCEⅢ500WB nuclear magnetic resonance spectrometer. The molar percentage of Si atoms in the long-chain branched polypropylene resin (hereinafter referred to as Si content) was calculated by the peak area ratio of the signal peak appearing at the chemical shift of 0.2ppm to the three signal peaks appearing at the chemical shift of 0.75-1.9ppm.

[0115] Example 1

[0116] Under vacuum, 1000 g of liquid propylene was added to the reactor, and then 0.4 g of hydrogen, 1.0 mmol of modified methylaluminoxane, 0.2 g of 3-butenylmethyldichlorosilane and 0.5 μmol of rac-Me2Si[2-Me-4-Ph(Ind)]2ZrCl2 catalyst (prepared by referring to Zhu hongping, et al. Chin. J. Org. Chem. 2018, 38, 2937) were added in sequence. The reaction temperature was controlled at 70 ° C. The polymerization reaction time was 60 min. After the polymerization was completed, the gas in the reactor was vented and the material was discharged. The product was added to 1000 g of deionized water and reacted at 80 ° C for 10 min. The excess deionized water was filtered off and vacuum dried at 50 ° C to obtain 532 g of polypropylene.

[0117] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and Si content of the polypropylene prepared above were tested. The test results are shown in Table 1.

[0118] Example 2

[0119] Under vacuum, 1000 g of liquid propylene was added to the reactor, and then 0.4 g of hydrogen, 1.0 mmol of modified methylaluminoxane, 0.2 g of 5-hexenylmethyldichlorosilane and 0.5 μmol of rac-Me2Si[2-Me-4-Ph(Ind)]2ZrCl2 catalyst (prepared according to Zhu hongping, et al. Chin. J. Org. Chem. 2018, 38, 2937) were added in sequence. The reaction temperature was controlled at 70 ° C. The polymerization reaction time was 60 min. After the polymerization was completed, the gas in the reactor was vented and the material was discharged. The product was added to 2000 g of deionized water and reacted at 100 ° C for 20 min. The excess deionized water was filtered off and vacuum dried at 50 ° C to obtain 520 g of polypropylene.

[0120] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and Si content of the polypropylene prepared above were tested. The test results are shown in Table 1.

[0121] Example 3

[0122] Under vacuum, 1000 g of liquid propylene was added to the reactor, and then 0.4 g of hydrogen, 1.0 mmol of modified methylaluminoxane, 0.2 g of 7-octenylmethyldichlorosilane and 0.5 μmol of rac-Me2Si[2-Me-4-Ph(Ind)]2ZrCl2 catalyst (prepared by referring to Zhu hongping, et al. Chin. J. Org. Chem. 2018, 38, 2937) were added in sequence. The reaction temperature was controlled at 90 ° C. The polymerization reaction time was 60 min. After the polymerization was completed, the gas in the reactor was vented and the material was discharged. The product was added to 500 g of deionized water and reacted at 50 ° C for 2 h. The excess deionized water was filtered off and vacuum dried at 50 ° C to obtain 533 g of polypropylene.

[0123] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and Si content of the polypropylene prepared above were tested. The test results are shown in Table 1.

[0124] Example 4

[0125] The method of Example 2 was followed, except that 0.1 g of hydrogen was added during the propylene polymerization process, and 340 g of polypropylene was finally obtained.

[0126] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and Si content of the polypropylene prepared above were tested. The test results are shown in Table 1.

[0127] Example 5

[0128] The method of Example 2 was followed, except that 1.0 g of hydrogen was added during the propylene polymerization process, and 740 g of polypropylene was finally obtained.

[0129] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 1

[0130] Example 6

[0131] The method of Example 2 is followed, except that the metallocene catalyst added during the propylene polymerization process is the same amount of rac-Me2Si (2-Me-4- i PrInd)2ZrCl2 catalyst (prepared with reference to Zhu hongping, et al. Chin. J. Org. Chem. 2018, 38, 2937), the co-catalyst is the same amount of ethylaluminoxane, the organosilane is the same amount of 9-decenylmethyldichlorosilane, the amount of deionized water is 100g, the hydrolysis reaction temperature is 70°C, the reaction time is 30min, and finally 595g of polypropylene is obtained.

[0132] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 1

[0133] Example 7

[0134] The method of Example 2 was followed, except that the metallocene catalyst added during the propylene polymerization process was rac-Me2Si(2-Me-4-C 10 H7Ind)2ZrCl2 catalyst (prepared with reference to Zhu hongping, et al. Chin. J. Org. Chem. 2018, 38, 2937), the organosilane is the same amount of 11-dodecenylmethyldichlorosilane, the amount of deionized water is 5000g, the hydrolysis reaction temperature is 90°C, the reaction time is 1.5h, and finally 558g of polypropylene is obtained.

[0135] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 1

[0136] Example 8

[0137] The method of Example 2 is followed, except that the metallocene catalyst added in the propylene polymerization process is a rac-PhP (2-Me-4-PhInd) 2ZrCl 2 catalyst (prepared with reference to Zhu hongping, et al. Chin. J. Org. Chem. 2018, 38, 2937), the co-catalyst is B (C6F5) 3 added in an amount of 5 μmol, and the organosilane is 5-hexenylethyldichlorosilane in the same amount, and finally 254 g of polypropylene is obtained.

[0138] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 1

[0139] Example 9

[0140] According to the method of Example 2, the difference is that the metallocene catalyst added in the propylene polymerization process is rac-CH2CH2(Ind)2TiCl2 catalyst (prepared with reference to Zhu hongping, et al. Chin. J. Org. Chem. 2018, 38, 2937), and the co-catalyst is [PhNH(Me)2] added in an amount of 2.5 μmol + [B(C6F5)4] - , the organosilane was 7-octenylethyldichlorosilane in the same amount, and finally 314g of polypropylene was obtained.

[0141] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 1

[0142] Example 10

[0143] The method of Example 2 was followed, except that 15 g of ethylene was added during the propylene polymerization process, and the added organosilane was the same amount of 9-decenylmethyldichlorosilane, to finally obtain 558 g of random copolymer polypropylene.

[0144] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the random copolymer polypropylene prepared above were tested. The test results are shown in Table 1

[0145] Embodiment 11

[0146] The method of Example 10 is followed, except that the amount of propylene added during the random copolymerization of propylene is 900 g, the α-olefin added is 1-butene and the amount added is 100 g, the metallocene catalyst added is the same amount of rac-CH2CH2-(2,4,7-Me3Ind)2ZrCl2 catalyst (prepared with reference to Zhu hongping, et al. Chin. J. Org. Chem. 2018, 38, 2937), the reaction temperature is controlled at 30°C, the organosilane is the same amount of 7-octenylmethyldichlorosilane, and finally 524 g of random copolymerized polypropylene is obtained.

[0147] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the random copolymer polypropylene prepared above were tested. The test results are shown in Table 2

[0148] Example 12

[0149] The method of Example 10 was followed, except that the α-olefin added during the random copolymerization of propylene was 1-hexene in an amount of 20 g, and the metallocene catalyst added was rac-H2C(3- t BuInd)2ZrCl2 catalyst (prepared with reference to Zhu hongping, et al. Chin. J. Org. Chem. 2018, 38, 2937), the organosilane was the same amount of 11-dodecenylethyldichlorosilane, and finally 488g of random copolymer polypropylene was obtained.

[0150] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the random copolymer polypropylene prepared above were tested. The test results are shown in Table 2

[0151] Embodiment 13

[0152] The method of Example 10 is followed, except that the α-olefin added during the random copolymerization of propylene is 1-octene and the amount added is 30 g, the catalyst added is the same amount of (5,6-Me2Ind)2ZrCl2 catalyst (prepared with reference to Zhuhongping, et al. Chin. J. Org. Chem. 2018, 38, 2937), and the organosilane is the same amount of 9-decenylethyldichlorosilane, and finally 392 g of random copolymerized polypropylene is obtained.

[0153] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the random copolymer polypropylene prepared above were tested. The test results are shown in Table 2

[0154] Embodiment 14

[0155] The method of Example 2 is followed, except that the metallocene catalyst added during the propylene polymerization process is the same amount of rac-H2C (3- t BuInd)2ZrCl2 catalyst (prepared with reference to Zhu hongping, et al. Chin. J. Org. Chem. 2018, 38, 2937), the organosilane was the same amount of 11-dodecenylethyldichlorosilane, and finally 349g of polypropylene was obtained.

[0156] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 2

[0157] Embodiment 15

[0158] The method of Example 2 was followed, except that the catalyst added during the propylene polymerization was the same amount of Me2C(Cp)(Flu)ZrCl2 catalyst (prepared with reference to Zhu hongping, et al. Chin. J. Org. Chem. 2018, 38, 2937), and finally 533 g of polypropylene was obtained.

[0159] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 2

[0160] Example 16

[0161] The method of Example 2 was followed, except that the catalyst added during the propylene polymerization process was the same amount of Ph2C(Cp)[2,3,6,7-(2,5,2',5'-Me4)-cyclo-(C6H4)2-Flu]ZrCl2 catalyst (prepared with reference to Zhuhongping, et al. Chin.J.Org.Chem.2018,38,2937), and the organosilane was the same amount of 9-decenylethyldichlorosilane, and finally 293 g of polypropylene was obtained.

[0162] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 2.

[0163] Embodiment 17

[0164] The method of Example 2 was followed, except that the catalyst added during the propylene polymerization process was 120 mg of a silica-supported rac-Me2Si(2-Me-4-Ph(Ind))2ZrCl2 catalyst (prepared according to the method described in CN1309669A), in which the mass content of the central metal atom Zr was 0.23%, the mass content of Al was 19.2%, and the organosilane was the same amount of 5-hexenylmethyldichlorosilane, and finally 556 g of polypropylene was obtained.

[0165] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 2.

[0166] Embodiment 18

[0167] The method of Example 2 was followed, except that the organosilane added during the propylene polymerization process was 0.02 g of 5-hexenylmethyldichlorosilane, and 516 g of polypropylene was finally obtained.

[0168] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 2.

[0169] Embodiment 19

[0170] The method of Example 2 was followed, except that the organic silane added during the propylene polymerization process was 0.5 g of 5-hexenylmethyldichlorosilane, and 516 g of polypropylene was finally obtained.

[0171] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 2.

[0172] Embodiment 20

[0173] The method of Example 2 was followed, except that after the propylene polymerization reaction was completed, the gas in the reactor was vented, and then 200 g of anhydrous hexane was added to the reactor for washing and filtering. This was repeated six times and then the material was discharged to finally obtain 617 g of polypropylene.

[0174] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 2.

[0175] Comparative Example 1

[0176] The method of Example 1 was followed, except that no organosilane was added during the propylene polymerization process, and 529 g of polypropylene was finally obtained.

[0177] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 3.

[0178] Comparative Example 2

[0179] The method of Example 2 was followed, except that no organosilane was added during the propylene polymerization process, and 517 g of polypropylene was finally obtained.

[0180] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 3.

[0181] Comparative Example 3

[0182] The method of Example 4 was followed, except that no organosilane was added during the propylene polymerization process, and 323 g of polypropylene was finally obtained.

[0183] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 3.

[0184] Comparative Example 4

[0185] The method of Example 5 was followed, except that no organosilane was added during the propylene polymerization process, and 500 g of polypropylene was finally obtained.

[0186] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 3.

[0187] Comparative Example 5

[0188] The method of Example 8 was followed, except that no organosilane was added during the propylene polymerization process, and 260 g of polypropylene was finally obtained.

[0189] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 3.

[0190] Comparative Example 6

[0191] The method of Example 10 was followed, except that no organosilane was added during the propylene polymerization process, and 553 g of random copolymer polypropylene was finally obtained.

[0192] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 3.

[0193] Comparative Example 7

[0194] The method of Example 13 was followed, except that no organosilane was added during the propylene polymerization process, and 500 g of random copolymer polypropylene was finally obtained.

[0195] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 3.

[0196] Comparative Example 8

[0197] The method of Example 17 was followed, except that no organosilane was added during the propylene polymerization process, and 560 g of polypropylene was finally obtained.

[0198] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 3.

[0199] Comparative Example 9

[0200] The method of Example 2 was followed, except that the organosilane added during the propylene polymerization was tetrachlorosilane in the same amount, and 526 g of polypropylene was finally obtained.

[0201] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 3.

[0202] Comparative Example 10

[0203] The method of Example 2 was followed, except that the organosilane added during the propylene polymerization was tetramethylsilane in the same amount, and 522 g of polypropylene was finally obtained.

[0204] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 3.

[0205] Comparative Example 11

[0206] Under vacuum, 1000g of liquid propylene was added to the reactor, and then 0.25mol of triethylaluminum, 0.5g of hydrogen, 0.2g of 5-hexenylmethyldichlorosilane and 18mg of olefin polymerization catalyst (MgCl2 / TiCl4 / BMMF, wherein the mass ratio of MgCl2, TiCl4 and BMMF was 80:12:8) were added in sequence. The reaction temperature was controlled at 70°C and the polymerization reaction was carried out for 30 minutes. After the polymerization was completed, the gas in the reactor was vented and the material was discharged. The product was added to 2000g of deionized water and reacted at 100°C for 20min. The excess deionized water was filtered off and vacuum dried at 50°C to obtain 551g of polypropylene.

[0207] The melting temperature, storage modulus, melt strength, melt index, gel content, weight average molecular weight and silicon content of the polypropylene prepared above were tested. The test results are shown in Table 3.

[0208] Table 1

[0209]

[0210] Table 2

[0211]

[0212] Table 3

[0213]

[0214] It can be seen from the results of Tables 1-3 that the polypropylene prepared by the method provided by the present invention has a high melt strength, which can reach more than 40 cN. At the same time, almost no gel is produced in the whole preparation process of polypropylene. It can be seen from the results of Comparative Examples 1-20 and Comparative Examples 9-10 that the organosilane provided by the present invention has a different effect as a branching auxiliary agent from silicon tetrahalide and tetraalkylsilane in the propylene polymerization process, and the polypropylene obtained by using the organosilane provided by the present invention has a higher melt strength. It can be seen from Comparative Example 18 and Comparative Example 11 that the long-chain branched polypropylene prepared by the metallocene catalyst has better mechanical properties with less organosilane dosage, and the insertion efficiency of the organosilane is higher.

[0215] also, Figure 1 The long-chain branched polypropylene of Example 1 1 H-NMR spectrum; Figure 2 is a comparison chart of the rheological properties of the long-chain branched polypropylene of Example 2 and the linear polypropylene of Comparative Example 2; Figure 3 The strain hardening exhibited in the extensional rheological test of the long-chain branched polypropylene of Example 3. Figure 1 and Figure 2 middle 1It can be seen from the H-NMR spectrum and the extensional rheological results that the method provided by the present invention successfully prepared long-chain branched polypropylene. Figure 3 It can be seen from the shear thinning results that the melt processing performance of the polymer prepared by the present invention is significantly improved.

[0216] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0217] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0218] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A long-chain branched polypropylene, characterized in that: The long-chain branched polypropylene resin has a structure shown in the following formula (I), and the molar percentage of Si atoms in the long-chain branched polypropylene resin is 0.0001‰-1.25‰, In formula (I), k is an integer of 0-18, m is an integer of 250-25000, n is between 1-5, x is an integer greater than 1, and R is a linear, branched or isomerized alkyl group having 1-20 carbon atoms. The long-chain branched polypropylene is prepared using a metallocene catalyst as a catalyst. The metallocene catalyst has Cp m R n MX q The present invention relates to a metal organic compound of a structure, wherein Cp is independently substituted or unsubstituted cyclopentadienyl and its derivatives; M is a transition metal of Groups 4, 5 and 6; R is a structural bridge that provides stereorigidity between two Cp; X is a halogen or a hydrocarbon group having 1 to 20 carbon atoms; and m=1-2, n=0-1, q=2-3, and the sum of m+q is equal to the oxidation state of the transition metal.

2. The long-chain branched polypropylene according to claim 1, wherein The long-chain branched polypropylene has a gel content of 0-1% by weight.

3. The long-chain branched polypropylene according to claim 1, wherein The molecular weight distribution of the long-chain branched polypropylene is less than 3.

4. The long-chain branched polypropylene according to claim 1, wherein The weight average molecular weight of the long-chain branched polypropylene is 1×10 4 -2×10 6 g / mol.

5. A long-chain branched polypropylene, characterized in that: The long-chain branched polypropylene resin has a structure shown in the following formula (II), and the molar percentage of Si atoms is 0.0001‰-1.25‰, In formula (II), k is an integer of 0-18, m is an integer of 250-50000, n is between 1-5, o is an integer of 0-50000, x is an integer greater than 1, R1 is a straight chain, branched chain or isomerized alkyl group having 1-20 carbon atoms, R2 is a hydrogen atom or a straight chain alkyl group having 2-7 carbon atoms, The long-chain branched polypropylene is prepared using a metallocene catalyst as a catalyst. The metallocene catalyst has Cp m R n MX q The present invention relates to a metal organic compound of a structure, wherein Cp is independently substituted or unsubstituted cyclopentadienyl and its derivatives; M is a transition metal of Groups 4, 5 and 6; R is a structural bridge that provides stereorigidity between two Cp; X is a halogen or a hydrocarbon group having 1 to 20 carbon atoms; and m=1-2, n=0-1, q=2-3, and the sum of m+q is equal to the oxidation state of the transition metal.

6. The long-chain branched polypropylene according to claim 5, wherein The long-chain branched polypropylene has a gel content of 0-1% by weight.

7. The long-chain branched polypropylene according to claim 5, wherein The molecular weight distribution of the long-chain branched polypropylene is less than 3.

8. The long-chain branched polypropylene according to claim 5, wherein The weight average molecular weight of the long-chain branched polypropylene is 1×10 4 -2×10 6 g / mol.

9. A method for preparing long-chain branched polypropylene, characterized in that: The method comprises the steps of polymerizing propylene, optional α-olefin and ω-olefin-based dichlorosilane in the presence of a metallocene catalyst, and hydrolyzing and condensing the polymer through Si-Cl bonds. The ω-olefin dichlorosilane is selected from the general formula R 1 SiCl2R 2 At least one of the compounds of the structure shown in the general formula, wherein R 1 is an olefin group having 2 to 20 carbon atoms and an olefin double bond at the end, R 2 is a straight chain, branched chain or isomerized alkyl group having 1 to 20 carbon atoms, The metallocene catalyst has Cp m R n MX q The present invention relates to a metal organic compound of a structure, wherein Cp is independently substituted or unsubstituted cyclopentadienyl and its derivatives; M is a transition metal of Groups 4, 5 and 6; R is a structural bridge that provides stereorigidity between two Cp; X is a halogen or a hydrocarbon group having 1 to 20 carbon atoms; and m=1-2, n=0-1, q=2-3, and the sum of m+q is equal to the oxidation state of the transition metal.

10. The method according to claim 9, wherein: The ω-olefin disilchloroalkane is at least one of 11-dodecenylmethyldichlorosilane, 11-dodecenylethyldichlorosilane, 11-dodecenylisopropyldichlorosilane, 9-decenylmethyldichlorosilane, 9-decenylbutyldichlorosilane, 9-decenylhexyldichlorosilane, 7-octenylethyldichlorosilane, 7-octenylmethyldichlorosilane, 7-octenyloctyldichlorosilane, 5-hexenylisopropyldichlorosilane, 5-hexenylmethyldichlorosilane, 5-hexenylethyldichlorosilane, 4-pentenylbutyldichlorosilane, 4-pentenylmethyldichlorosilane, 4-pentenylethyldichlorosilane, 3-butenylisopropyldichlorosilane, 3-butenylmethyldichlorosilane and 3-butenylethyldichlorosilane.

11. The method according to claim 9 or 10, wherein: The polymerization is carried out in the presence of a cocatalyst selected from alkylaluminoxane compounds or organic boron compounds.

12. The method according to claim 11, wherein: For alkylaluminoxane compounds, the amount of the co-catalyst added is calculated based on the molar ratio of Al to the transition metal M in the main catalyst, which is Al:M=10-50000:1; for organic boride, the amount of the co-catalyst added is calculated based on the molar ratio of B to the transition metal M in the main catalyst, which is B:M=0.1-100:

1.

13. The method according to claim 12, wherein: For alkylaluminoxane compounds, the amount of the co-catalyst added is calculated based on the molar ratio of Al to the transition metal M in the main catalyst, which is Al:M=100-5000:1; for organic boride, the amount of the co-catalyst added is calculated based on the molar ratio of B to the transition metal M in the main catalyst, which is B:M=0.5-10:

1.

14. The method according to claim 9 or 10, wherein: The weight ratio of propylene to ω-olefin dichlorosilane is 1:0.001‰-5.0‰.

15. The method according to claim 9 or 10, wherein: The weight ratio of the catalyst to the polymerization monomer calculated on the basis of transition metal M is 0.01‰-5.0‰:

1.

16. The method according to claim 9 or 10, wherein: The α-olefin is at least one of ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-nonene.

17. The method according to claim 16, wherein: The amount of propylene used is such that the content of propylene units in the long-chain branched polypropylene is 80-99.8% by weight, and the content of α-olefin units is 0.1-10% by weight.

18. The method according to claim 9 or 10, wherein: The method of hydrolyzing and condensing the polymer via Si-Cl bonds comprises: contacting the polymer with water.

19. Long-chain branched polypropylene prepared by the method according to any one of claims 9 to 18.

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