Polyolefin elastomer material and preparation method thereof

Abstract

The invention discloses a polyolefin elastomer material and a preparation method thereof. A molecular chain of the polyolefin elastomer contains a Si-O bond structure or a Si-N bond structure, and the molar ratio of a Si-O bond or a Si-N bond to a C-C bond in the polyolefin elastomer is 0.0001%-1%. The preparation method of the polyolefin elastomer comprises the following steps: adding a solvent, a comonomer, a cocatalyst, a main catalyst and omega-alkylene halosilane into a water-free and oxygen-free reaction kettle, after the polymerization temperature rises to a set value, introducing ethylene or propylene gas to a set polymerization pressure, and starting a polymerization reaction; and introducing a mixed slurry or a mixed solution of an auxiliary agent and a solvent into the product solution system, stirring to obtain a solution rich in the polyolefin elastomer, and then devolatilizing and granulating to obtain the granular polyolefin elastomer. The polyolefin elastomer has the characteristic of controllable long-chain branch content, and has the outstanding characteristics of high melt strength, high tensile modulus and remarkable rheological shear thinning phenomenon in processing and use.

Description

Technical Field

[0001] The invention belongs to the field of polyolefin elastomer production, and relates to a polyolefin elastomer material and a preparation method thereof. Specifically, the invention relates to a polyolefin elastomer material containing Si-O bonds or Si-N bonds and a preparation method thereof. Background Art

[0002] Polyolefin elastomers mainly include polyethylene elastomers and polypropylene elastomers, which have the advantages of high elasticity, easy processing, high transparency, good toughening and modification effects, and are widely used in photovoltaics, plastic modification, foaming and other fields. Polyethylene elastomers are copolymers of ethylene and α-olefins (1-butene, 1-hexene and 1-octene, etc.), and polypropylene elastomers are copolymers of propylene and α-olefins (ethylene, 1-butene and 1-hexene, etc.). Both elastomers have short-chain branching structures in their molecular chains, and it is difficult to prepare polyolefin elastomers containing long-chain branching structures. In order to improve the melt strength, melt fluidity and processing stability of polyolefin products, it is often necessary to introduce long-chain branching structures into the molecular chains of polyolefin materials. However, long-chain α-olefin macromolecular comonomers are difficult to coordinate with ethylene and insert into the polymer chain due to large steric hindrance. Therefore, the preparation of polyolefin elastomers with long-chain branching structures has always been a challenge.

[0003] In addition, the existing polyolefin elastomer materials all have CC bonds as the main chain, which is difficult to recycle. How to achieve efficient recycling and recycling of polyolefin elastomer materials has always been a development trend.

[0004] The document Macromolecules, 2018, 51, 8790 reports a method for preparing long-chain branched comb-shaped polyolefin elastomer (CPOE) by cascade polymerization, in which a crystalline PE macromonomer (PE-M) with a double bond at the end is prepared by ethylene homopolymerization, and then CPOE is synthesized by ethylene / 1-octene / PE-M ternary copolymerization. The main chain of CPOE prepared by this method is an ethylene / 1-octene random copolymer, and the side chain is a crystalline PE. The length and number of the side chains are controllable, and the product exhibits excellent mechanical properties, processing properties and thermal properties. However, this method has problems such as high cost of the catalytic system, low catalytic activity and complex process, and the main chain of the molecular chain of the product is CC bond, which is difficult to recycle.

[0005] In addition to the direct synthesis method, the preparation of long-chain branched polyolefin elastomers also includes high-energy radiation method and melt branching method. However, the high-energy radiation method has the problems of complex process and high cost. Although the melt branching method is easy to operate and more economical, and more suitable for industrial large-scale production, it also inevitably has problems such as high-temperature degradation and side reactions.

[0006] Direct synthesis is still the development trend of long-chain branched polyolefin elastomers, but how to cleverly introduce long-chain branched structures into polymer molecular chains remains a challenge. Summary of the invention

[0007] In view of the above problems, the present invention provides a polyolefin elastomer material and a preparation method thereof. The polyolefin elastomer material of the present invention has the characteristics of controllable long-chain branch content, and has the outstanding characteristics of high melt strength and significant rheological shear thinning phenomenon during processing and use. It can be widely used in the production of products in the fields of films, foaming, fibers, etc., and can improve the mechanical properties of products, improve thermal stability, improve foaming performance and improve the wear resistance of products.

[0008] In order to achieve the above-mentioned object, one of the objects of the present invention is to provide a polyolefin elastomer material, wherein the polyolefin elastomer molecular chain contains a Si-O bond structure or a Si-N bond structure, and the molar ratio of the Si-O bond or Si-N bond to the CC bond in the polyolefin elastomer is 0.0001%-1%.

[0009] In the polyolefin elastomer of the present invention, the Si-O bond is obtained by the reaction of the Si-Cl bond or the Si-Br bond with the OH bond, and the Si-N bond is obtained by the reaction of the Si-Cl bond or the Si-Br bond with the NH bond.

[0010] Another object of the present invention is to provide a method for preparing the polyolefin elastomer: adding a solvent, a comonomer, a co-catalyst, a main catalyst, and an ω-olefin halosilane into an anhydrous and oxygen-free reactor, introducing ethylene or propylene gas to a set polymerization pressure to start a polymerization reaction after the polymerization temperature rises to a set value, and after the polymerization is completed, introducing a mixed slurry or mixed solution of the auxiliary agent and the solvent into the product solution system, stirring to obtain a solution rich in the polyolefin elastomer, and then devolatilizing and granulating to obtain a granular polyolefin elastomer.

[0011] The solvent of the present invention is selected from one or more of n-pentane, isopentane, n-hexane, cyclohexane, n-heptane, 2-methylhexane, 3-methylhexane, isoparaffin Isopar C and isoparaffin Isopar E.

[0012] The comonomer described in the present invention is selected from one or more of 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene and 1-decene.

[0013] The main catalyst of the present invention is selected from one or more of a bridged metallocene catalyst, a non-bridged metallocene catalyst, and a constrained geometry catalyst.

[0014] The co-catalyst of the present invention is selected from one or more of methylaluminoxane, modified methylaluminoxane, tri(pentafluorophenyl)borane, borate, triethylaluminum, triisobutylaluminum, trihexylaluminum and trioctylaluminum.

[0015] The number of Si-X bonds in the ω-olefin halosilane of the present invention is 1, 2 or 3 (X is Cl or Br), and the olefin group is a straight-chain or branched α-olefin group having 1 to 50 carbon atoms. Preferably, the ω-olefin halosilane is selected from 9-decenyldimethylchlorosilane, 9-decenylmethyldichlorosilane, 9-decenyltrichlorosilane, 9-decenyldiethylchlorosilane, 9-decenylethyldichlorosilane, 8-nonenyldimethylchlorosilane, 8-nonenylmethyldichlorosilane, 8-nonenyltrichlorosilane, 8-nonenyldiethylchlorosilane, 8-nonenylethyldichlorosilane, 7-octenyldimethylchlorosilane, 7-octenylmethyldichlorosilane, 7-octenyltrichlorosilane, 7-octenyldiethylchlorosilane, 7-octenylethyldichlorosilane, 6-heptenyldimethylchlorosilane, 6-heptenylmethyldichlorosilane, One or more of 6-heptenyltrichlorosilane, 6-heptenyldiethylchlorosilane, 6-heptenylethyldichlorosilane, 5-hexenyldimethylchlorosilane, 5-hexenylmethyldichlorosilane, 5-hexenyltrichlorosilane, 5-hexenyldiethylchlorosilane, 5-hexenylethyldichlorosilane, 4-pentenyldimethylchlorosilane, 4-pentenylmethyldichlorosilane, 4-pentenyltrichlorosilane, 4-pentenyldiethylchlorosilane, 4-pentenylethyldichlorosilane, 3-butenyldimethylchlorosilane, 3-butenylmethyldichlorosilane, 3-butenyltrichlorosilane, 3-butenyldiethylchlorosilane, and 3-butenylethyldichlorosilane.

[0016] According to the method for preparing a polyolefin elastomer of the present invention, the polymerization time is 5-180 min, the polymerization temperature is 100-180° C., the polymerization pressure is 10-60 bar, the auxiliary agent content in the mixed slurry or mixed solution of the auxiliary agent and the solvent is 1-50wt%, the auxiliary agent is selected from one or more of nano-silica, cage-shaped polysilsesquioxane, polysilazane, and hexamethylcyclotrisilazane, and the auxiliary agent contains at least 2 -OH hydroxyl groups or at least 2 -NH2 amino groups or at least 2 -NH imino groups. Preferably, the cage-shaped polysilsesquioxane auxiliary agent is selected from one or more of octa(3-hydroxy-3-methylbutyldimethylsiloxane), octa(aminophenyltrioxysilane), N-phenylamino-cage-shaped polysilsesquioxane (CAS: 1708993-28-5), octamaleamic acid cage-shaped polysilsesquioxane, trisilanol cyclohexyl cage-shaped polysilsesquioxane (CAS: 4115-83-7), trisilanol cyclopentyl cage-shaped polysilsesquioxane (CAS: 135225-24-0), disilanol isobutyl cage-shaped polysilsesquioxane (CAS: 307531-90-4), trisilanol ethyl cage-shaped polysilsesquioxane, and tetrasilanol phenyl cage-shaped polysilsesquioxane. After the polymerization is completed, the mixed slurry or mixed solution of the product solution system, the auxiliary agent and the solvent is stirred for 10-120 min.

[0017] In the polyolefin elastomer of the present invention, the weight proportion of the comonomer is 10-60wt%, the weight proportion of the ω-olefin halosilane is 0.0005-2wt%, and the weight proportion of the auxiliary agent is 0.001-5wt%.

[0018] The molar ratio of the co-catalyst to the main catalyst of the present invention (the ratio of the central metal Al in the co-catalyst to the transition metal M in the main catalyst or the ratio of the central non-metal B in the co-catalyst to the transition metal M in the main catalyst) is 1.05-1000.

[0019] The weight average molecular weight of the polyolefin elastomer of the present invention is 10000-500000 g / mol, the molecular weight distribution is 1.5-10, and the density is 0.856-0.900 g / cm 3 , and the weight average molecular weight can be adjusted by introducing hydrogen during the preparation process.

[0020] According to the characteristics of the polyolefin elastomer described in the present invention, the polyolefin elastomer can be widely used in the preparation of films, fibers, toughening materials, pipes, profiles, photovoltaic films, wires and cables, foamed products and engineering plastic modified products.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) By adding an appropriate amount of ω-olefin halosilane and an auxiliary agent containing at least 2 -OH hydroxyl groups or at least 2 -NH2 amino groups or at least 2 -NH imino groups during the preparation process, the Si-O bond structure or Si-N bond structure can be introduced into the polymer main chain by utilizing the reaction of Si-Cl bond or Si-Br bond with OH bond and the reaction of Si-Cl bond or Si-Br bond with NH bond, so that part of the copolymerized chain segment of ethylene or propylene and the comonomer serves as a long-chain branch side chain. By adjusting the amount of ω-olefin halosilane added and the amount of the auxiliary agent added, the long-chain branch structure content of the polymer can be regulated.

[0023] (2) By introducing Si-O bond structure or Si-N bond structure into the polymer main chain, the easy degradation characteristics of Si-O bond structure or Si-N bond structure can be utilized to achieve molecular chain breaking and efficient recovery and recycling of polyolefin elastomer through hydrolysis reaction or alcoholysis reaction in acidic or alkaline solution.

[0024] (3) The introduction of long-chain branching structure can effectively improve melt strength and tensile modulus, improve shear thinning properties, and increase melt fluidity and processing stability. The above properties can be regulated according to the amount of long-chain branching content to develop polyolefin elastomer products with different physical properties and performance to meet the requirements of films, foaming, fibers, reinforcement and toughening, photovoltaic films, wires and cables and other fields.

[0025] (4) By introducing Si-O bond structure or Si-N bond structure into the polymer main chain, the additive can be effectively inserted into the polymer chain segment to improve the thermal stability of the polyolefin elastomer material. In addition, the introduction of Si-O bond or Si-N bond polar groups can improve the compatibility of the polyolefin elastomer material with the inorganic filler, thereby improving the performance of the composite material, such as impact resistance, adhesion, biocompatibility, etc., and broadening the application scope of the polyolefin elastomer material in blending modification. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the H-NMR spectrum of polyolefin elastomer A.

[0027] Figure 2 It is the rheological curve diagram of polyolefin elastomer A and E. DETAILED DESCRIPTION

[0028] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0029] The following methods are used to test the structure or performance of the polyolefin elastomers produced in the examples described:

[0030] High temperature gel permeation chromatography (GPC) is used to test the weight average molecular weight and molecular weight distribution of polyolefin elastomers.

[0031] Gradient densitometer is used to test the density of polyolefin elastomers.

[0032] The carbon NMR spectrum is used to analyze the insertion rate of comonomers in polyolefin elastomers, and the hydrogen NMR spectrum is used to analyze the content of SiO or Si-N bonds in polyolefin elastomers.

[0033] Rheological sweep frequency test is used to analyze the relationship between the complex viscosity of polyolefin elastomers and the shear frequency.

[0034] Example 1

[0035] 2L of n-hexane, 1.2L of 1-hexene, 6μmol of tri(pentafluorophenyl)borane, 2000μmol of methylaluminoxane, 5μmol of constrained geometry catalyst (CAS: 135072-61-6), and 1mmol of 6-heptenylmethyldichlorosilane were added to a 5L reactor without water or oxygen. After the polymerization temperature was raised to 150°C, ethylene gas was introduced to set the polymerization pressure to 35 bar to start the polymerization reaction. After 25 minutes of polymerization, a mixed slurry of the auxiliary agent octa(aminophenyltrioxysilane) and n-hexane (the mixed slurry contained 3mmol of the auxiliary agent) was introduced into the product solution system. After stirring for 60 minutes, a solution rich in polyolefin elastomer A was obtained, and then devolatilization, granulation and other steps were performed to obtain granular polyolefin elastomer A. The analysis and characterization results of polyolefin elastomer A are shown in Table 1.

[0036] Example 2

[0037] 1.8L cyclohexane, 1.6L 1-octene, 6μmol tri(pentafluorophenyl)borane, 1200μmol modified methylaluminoxane, 5μmol constrained geometry catalyst (CAS: 135072-62-7), 0.8mmol 5-hexenylethyldichlorosilane were added to a 5L reactor without water or oxygen. After the polymerization temperature was raised to 170°C, ethylene gas was introduced to set the polymerization pressure to 40bar to start the polymerization reaction. After 100min of polymerization, a mixed slurry of the auxiliary agent octamaleamic acid cage silsesquioxane and cyclohexane (the mixed slurry contained 5mmol of the auxiliary agent) was introduced into the product solution system. After stirring for 20min, a solution rich in polyolefin elastomer B was obtained, and then devolatilization, granulation and other steps were performed to obtain granular polyolefin elastomer B. The analysis and characterization results of polyolefin elastomer B are shown in Table 1.

[0038] Example 3

[0039] 2.5L of isoalkane Isopar E, 1.2L of 1-heptene, 6μmol of tri(pentafluorophenyl)borane, 5μmol of metallocene catalyst (CAS: 132510-07-7), and 1.5mmol of 5-hexenylethyldichlorosilane were added to a 5L reactor without water or oxygen. After the polymerization temperature was raised to 170°C, ethylene gas was introduced to set the polymerization pressure to 25bar to start the polymerization reaction. After 80 minutes of polymerization, a mixed slurry of the auxiliary agent trisilanol cyclopentyl cage-shaped polysilsesquioxane (CAS: 135225-24-0) and isoalkane Isopar E (the mixed slurry contained 2mmol of the auxiliary agent) was introduced into the product solution system. After stirring for 100 minutes, a solution rich in polyolefin elastomer C was obtained, and then devolatilization, granulation and other steps were performed to obtain granular polyolefin elastomer C. The analysis and characterization results of polyolefin elastomer C are shown in Table 1.

[0040] Example 4

[0041] 1.8L of n-hexane, 1.6L of 1-hexene, 6μmol of tri(pentafluorophenyl)borane, 1200μmol of modified methylaluminoxane, 5μmol of metallocene catalyst (CAS: 132510-07-7), and 0.8mmol of 5-hexenylethyldichlorosilane were added to a 5L reactor without water or oxygen. After the polymerization temperature was raised to 105°C, propylene gas was introduced to set the polymerization pressure to 11bar to start the polymerization reaction. After 50min of polymerization, a mixed slurry of the auxiliary agent disilanol isobutyl cage-shaped polysilsesquioxane (CAS: 307531-90-4) and n-hexane (the mixed slurry contained 2mmol of the auxiliary agent) was introduced into the product solution system. After stirring for 40min, a solution rich in polyolefin elastomer D was obtained, and then devolatilization, granulation and other steps were performed to obtain granular polyolefin elastomer D. The analysis and characterization results of polyolefin elastomer D are shown in Table 1.

[0042] Comparative Example 1

[0043] 2L of n-hexane, 1.2L of 1-hexene, 6μmol of tri(pentafluorophenyl)borane, 2000μmol of methylaluminoxane, and 5μmol of constrained geometry catalyst (CAS: 135072-61-6) were added to a 5L reactor without water or oxygen. After the polymerization temperature was raised to 150°C, ethylene gas was introduced to set the polymerization pressure to 35 bar to start the polymerization reaction. After 25 minutes of polymerization, the product solution system was subjected to devolatilization, granulation and other steps to obtain granular polyolefin elastomer E. The analysis and characterization results of polyolefin elastomer E are shown in Table 1.

[0044] Table 1 - AE characterization results of polyolefin elastomers

[0045]

[0046]

[0047] From Table 1, Figure 1 and Figure 2 It can be seen that after the Si-O bond is introduced into the molecular chain of polyolefin elastomer A, the long-chain branching structure can be effectively introduced, the melt strength of polyolefin elastomer A is improved, and the shear thinning property is more significant, which is beneficial to improve melt fluidity, processing stability and tensile modulus of elastomer. In comparative example 1, the molecular chain of polyolefin elastomer E does not contain Si-O bonds and long-chain branching structures, but only has short-chain branching structures of conventional polyolefin elastomers, that is, short-chain branching structures introduced by comonomers, and the melt strength and tensile modulus are low and the shear thinning property is not significant. In addition, the long-chain branching content of the polymer can be regulated by adjusting the amount of ω-olefin halosilane added and the amount of additive added, so as to develop polyolefin elastomer products with different physical properties and performance characteristics to meet the requirements of thin films, foaming, fibers, reinforcement and toughening, photovoltaic adhesive films, wires and cables, and other fields.

[0048] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A polyolefin elastomer material, characterized in that: The polyolefin elastomer molecular chain contains Si-O bond structure or Si-N bond structure, and the molar ratio of Si-O bond or Si-N bond to CC bond in the polyolefin elastomer is 0.0001%-1%.

2. The polyolefin elastomer according to claim 1, characterized in that The Si-O bond is obtained by the reaction of a Si-Cl bond or a Si-Br bond with an OH bond, and the Si-N bond is obtained by the reaction of a Si-Cl bond or a Si-Br bond with an NH bond.

3. A method for preparing a polyolefin elastomer according to claim 1, characterized in that: The steps include: A solvent, a comonomer, a cocatalyst, a main catalyst and ω-olefin halosilane are added to a reaction kettle without water and oxygen. After the polymerization temperature rises to a set value, ethylene or propylene gas is introduced to a set polymerization pressure to start the polymerization reaction. After the polymerization is completed, a mixed slurry or mixed solution of the auxiliary agent and the solvent is introduced into the product solution system, and a solution rich in the polyolefin elastomer is obtained after stirring, and then devolatilization and granulation are performed to obtain a granular polyolefin elastomer.

4. The method for preparing a polyolefin elastomer according to claim 3, characterized in that: The solvent is selected from one or more of n-pentane, isopentane, n-hexane, cyclohexane, n-heptane, 2-methylhexane, 3-methylhexane, isoparaffin Isopar C, and isoparaffin Isopar E; the comonomer is selected from one or more of 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, and 1-decene; the main catalyst is selected from one or more of a bridged metallocene catalyst, a non-bridged metallocene catalyst, and a constrained geometry catalyst; the cocatalyst is selected from one or more of methylaluminoxane, modified methylaluminoxane, tri(pentafluorophenyl)borane, borates, triethylaluminum, triisobutylaluminum, trihexylaluminum, and trioctylaluminum.

5. The method for preparing a polyolefin elastomer according to claim 3, characterized in that: The number of Si-X bonds in the ω-olefin halosilane is 1, 2 or 3, X is Cl or Br, and the olefin group is a straight or branched α-olefin group with 1 to 50 carbon atoms; preferably, the ω-olefin halosilane is selected from 9-decenyldimethylchlorosilane, 9-decenylmethyldichlorosilane, 9-decenyltrichlorosilane, 9-decenyldiethylchlorosilane, 9-decenylethyldichlorosilane, 8-nonenyldimethylchlorosilane, 8-nonenylmethyldichlorosilane, 8-nonenyltrichlorosilane, 8-nonenyldiethylchlorosilane, 8-nonenylethyldichlorosilane, 7-octenyldimethylchlorosilane, 7-octenylmethyldichlorosilane, 7-octenyltrichlorosilane, 7-octenyldiethylchlorosilane, 7-octenylethyl One or more of dichlorosilane, 6-heptenyldimethylchlorosilane, 6-heptenylmethyldichlorosilane, 6-heptenyltrichlorosilane, 6-heptenyldiethylchlorosilane, 6-heptenylethyldichlorosilane, 5-hexenyldimethylchlorosilane, 5-hexenylmethyldichlorosilane, 5-hexenyltrichlorosilane, 5-hexenyldiethylchlorosilane, 5-hexenylethyldichlorosilane, 4-pentenyldimethylchlorosilane, 4-pentenylmethyldichlorosilane, 4-pentenyltrichlorosilane, 4-pentenyldiethylchlorosilane, 4-pentenylethyldichlorosilane, 3-butenyldimethylchlorosilane, 3-butenylmethyldichlorosilane, 3-butenyltrichlorosilane, 3-butenyldiethylchlorosilane, and 3-butenylethyldichlorosilane.

6. The method for preparing a polyolefin elastomer according to claim 3, characterized in that: The polymerization reaction time is 5-180min, the polymerization temperature is 100-180°C, the polymerization pressure is 10-60bar, the auxiliary agent content in the mixed slurry or mixed solution of the auxiliary agent and the solvent is 1-50wt%, the auxiliary agent is selected from one or more of nano-silica, cage-shaped polysilsesquioxane, polysilazane, and hexamethylcyclotrisilazane, and the auxiliary agent contains at least 2 -OH hydroxyl groups or at least 2 -NH2 amino groups or at least 2 -NH imino groups; preferably, the cage-shaped polysilsesquioxane auxiliary agent is selected from octa(3-hydroxy One or more of silanol-3-methylbutyldimethylsiloxane), octa(aminophenyltrioxysilane), N-phenylamino-cage polysilsesquioxane, octamaleamic acid cage polysilsesquioxane, trisilanol cyclohexyl cage polysilsesquioxane, trisilanol cyclopentyl cage polysilsesquioxane, disilanol isobutyl cage polysilsesquioxane, trisilanol ethyl cage polysilsesquioxane, and tetrasilanol phenyl cage polysilsesquioxane. After the polymerization, the mixed slurry or mixed solution of the product solution system, the auxiliary agent and the solvent is stirred for 10-120 min.

7. The method for preparing a polyolefin elastomer according to claim 3, characterized in that: In the polyolefin elastomer, the weight proportion of the comonomer is 10-60wt%, the weight proportion of the ω-olefin halosilane is 0.0005-2wt%, and the weight proportion of the auxiliary agent is 0.001-5wt%.

8. The method for preparing a polyolefin elastomer according to claim 4, characterized in that: The molar ratio of the co-catalyst to the main catalyst is 1.05-1000, calculated based on the ratio of the central metal Al in the co-catalyst to the transition metal M in the main catalyst or the ratio of the central non-metal B in the co-catalyst to the transition metal M in the main catalyst.

9. The method for preparing a polyolefin elastomer according to any one of claims 1 to 8, wherein the weight average molecular weight of the polyolefin elastomer is 10000-500000 g / mol, the molecular weight distribution is 1.5-10, and the density is 0.856-0.900 g / cm 3 , and the weight average molecular weight can be adjusted by introducing hydrogen during the preparation process.

10. Use of the polyolefin elastomer according to claim 1 or 2 in the preparation of films, fibers, toughening materials, pipes, profiles, photovoltaic films, wires and cables, foamed products and engineering plastic modified products.

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