Ethylene and alpha-olefin multipolymer as well as preparation method and application thereof

Abstract

The invention discloses an ethylene and alpha-olefin multipolymer, relates to the technical field of olefin polymerization, and in particular relates to an ethylene and alpha-olefin multipolymer as well as a preparation method and application thereof, the haze of the ethylene and alpha-olefin multipolymer is 1-7%, and the light transmittance is gt; the volume resistivity is gt; the molecular weight is 5.0 * 10 < 17 > omega.cm, the weight-average molecular weight is 70000-130000, and the crystallinity is 15%-35%; the method comprises the following steps: controlling the ratio of the mass flow rate of a liquid phase material A entering a fluidized bed reactor to the mass flow rate of circulating gas, and controlling the molar ratio of 1-butene / ethylene, the molar ratio of 1-hexene / ethylene, the molar ratio of 1-octene / ethylene, the molar ratio of a molecular weight regulator / ethylene, the molar content of an inert condensing agent and the injection position of the liquid phase material A in the circulating gas; the ethylene and alpha-olefin multipolymer with low haze, high light transmittance and high volume resistivity is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of olefin polymerization, and in particular to an ethylene and alpha-olefin multi-polymer and a preparation method and application thereof. Background Art

[0002] Ethylene-octene copolymer products have attracted much attention from domestic and foreign petrochemical companies due to their excellent performance and broad application prospects. Especially in the field of photovoltaic films, polyolefin materials represented by ethylene-octene copolymer (POE) have excellent light transmittance, electrical insulation, water vapor barrier, excellent weather resistance and resistance to induced potential difference attenuation (PID) performance, and are considered to be ideal materials to replace ethylene-vinyl acetate copolymer (EVA) packaging materials. The high branching content of POE improves the light transmittance of photovoltaic films. At the same time, the saturation of its molecular chain makes photovoltaic films have excellent heat aging resistance and UV resistance. Therefore, POE has great application potential in the field of photovoltaic films.

[0003] The main production processes of ethylene-octene copolymer products include solution process, dispersion polymerization process and slurry process. As the mainstream process for producing ethylene / 1-octene copolymer products at this stage, the solution process can control the molecular weight and distribution, comonomer content and stereoregularity of the obtained polymer by selecting appropriate reactor conditions, although the polymer concentration in the reaction system is generally low. In the solution process, the monomer and polymer are dissolved in an inert solution, so there is no problem of polyethylene particles adsorbing a large amount of octene on the surface in the gas phase process, which causes adhesion. Basically, ethylene-octene copolymers in the full density range can be produced. However, since the solution process reacts at a higher temperature (200°C or higher), the Ziegler-Natta catalyst generally used has low activity, so the residue in the polymer must be removed, and a deslagging process needs to be added. At the same time, the solution process has high production costs, great difficulty in solvent separation, high energy consumption, and expensive product prices, which limits the large-scale application of its ethylene-octene copolymer products. At present, all solution process technologies are owned by foreign companies, and original research and application of ethylene / 1-octene copolymerization in China are very rare. Dispersion polymerization is reported in patents such as CN103384686A. Although the patent claims that the polymer concentration can reach 40wt%, this technology is still in the laboratory test stage and has not yet been reported for industrialization. For the slurry method, since the melting point of ethylene / 1-octene copolymer products is low, they are very easy to swell in solvents, and the products are easy to melt and agglomerate, making stable and efficient production difficult.

[0004] At present, domestic ethylene-octene copolymer products are still in a situation of structural oversupply and weak production competitiveness. There are few special grades of high-performance and multifunctional materials, which cannot meet the domestic market demand, including the photovoltaic film field. Therefore, it is urgent to innovate the production process and technology of ethylene-octene copolymers, improve the market competitiveness of ethylene-octene copolymer products, and reduce their dependence on imports.

[0005] The gas phase fluidized bed ethylene polymerization process is the mainstream process that accounts for more than 40% of the global polyethylene production capacity. If the gas phase fluidized bed is directly used to produce ethylene-octene copolymers, there are problems such as low octene partial pressure in the gas phase and low octene / ethylene ratio, which makes it difficult to increase the octene insertion rate in the product.

[0006] Industrial tests have found that after improving the existing gas phase fluidized bed production equipment and process, a linear low-density ethylene and α-olefin multi-copolymer copolymer containing octene components with low haze, high transmittance, and high volume resistivity can be produced, which is suitable for the preparation of photovoltaic films and is expected to greatly expand the high-end application market of linear low-density polyethylene (LLDPE) materials. At the same time, the fluidized bed process has the advantages of simple operation, solvent-free, green and environmentally friendly, and low cost. If LLDPE is used instead of POE to prepare photovoltaic films, the production cost of photovoltaic films will be significantly reduced, which is of great significance for the development of high-performance, domestically produced ethylene-octene copolymer special materials. Summary of the invention

[0007] In view of the above problems, the present invention provides an ethylene and α-olefin multipolymer and a preparation method and application thereof. The ethylene and α-olefin multipolymer has the characteristics of low haze, high transmittance, and high volume resistivity, and is suitable for the field of photovoltaic film manufacturing. The production process has the advantages of simple operation, solvent-free, green and environmentally friendly, and low cost.

[0008] In order to solve the above technical problems, the first aspect of the present invention provides an ethylene and α-olefin multi-polymer, the haze is 1% to 7%, the light transmittance is greater than 87%, the volume resistivity is greater than 5.0×10 17 Ω·cm, weight average molecular weight of 70000 to 130000, and crystallinity of 15% to 35%.

[0009] According to some embodiments of the present invention, based on the total molar amount of the ethylene and α-olefin multipolymer, the molar content of the ethylene structural unit in the ethylene and α-olefin multipolymer is 80 mol% to 96 mol%, the molar content of the 1-butene structural unit is 2.0 mol% to 10 mol%, the molar content of the 1-hexene structural unit is 0 mol% to 3.5 mol%, and the molar content of the 1-octene structural unit is 0.3 mol% to 15 mol%.

[0010] In the present invention, the contents of ethylene structural units, 1-butene structural units, 1-hexene structural units and 1-octene structural units in the ethylene and α-olefin multi-polymer are measured using a Bruker Advance 2B 400MHz 13 C-NMR is measured. Among them, the ethylene structural unit is a vinyl group unit connected to the molecular chain through a carbon-carbon covalent bond, the 1-butene structural unit is a 1-butene group unit connected to the molecular chain through a carbon-carbon covalent bond, the 1-hexene structural unit is a 1-hexene group unit connected to the molecular chain through a carbon-carbon covalent bond, and the 1-octene structural unit is a 1-octene group unit connected to the molecular chain through a carbon-carbon covalent bond.

[0011] According to some embodiments of the present invention, the DSC melting curve of the ethylene and α-olefin multipolymer includes a first melting peak T1 and a second melting peak T2; preferably, the temperature range of the first melting peak T1 is 105°C to 135°C, and the temperature range of the second melting peak T2 is 90°C to 110°C; further preferably, the peak area ratio of the second melting peak T2 to the first melting peak T1 is 0.01 to 0.5.

[0012] In the present invention, the temperature distribution of the first melting peak T1 refers to the distribution of the melting temperature Tm1 corresponding to the first melting peak T1 in the DSC melting curve of the copolymer; the temperature distribution of the second melting peak T2 refers to the distribution of the melting temperature Tm2 corresponding to the second melting peak T2 in the DSC melting curve of the copolymer.

[0013] In the present invention, the area ST1 of the first melting peak and the area ST2 of the second melting peak are obtained by integrating the DSC melting curve of the copolymer.

[0014] According to some embodiments of the present invention, the molecular weight distribution index of the ethylene and α-olefin multipolymer is 2-8, preferably 3-5.

[0015] According to some embodiments of the present invention, the density of the ethylene and α-olefin multipolymer is 0.885 g / cm 3 ~0.930g / cm 3 , preferably 0.89 g / cm 3 ~0.92g / cm 3 ; Under the conditions of temperature of 190°C and load of 2.16kg, the melt index of the ethylene and α-olefin multipolymer is 0.5g / 10min~15g / 10min, preferably 0.58g / 10min~8g / 10min; the melting point of the ethylene and α-olefin multipolymer is 80°C~130°C, preferably 100°C~125°C.

[0016] The second aspect of the present invention provides a method for preparing the above-mentioned ethylene and α-olefin multipolymer, comprising contacting a liquid material A from the side wall of a fluidized bed reactor with a liquid material B from the bottom of the fluidized bed reactor and a gaseous material containing ethylene in the presence of a catalyst to react and generate the ethylene and α-olefin multipolymer.

[0017] According to some embodiments of the present invention, the α-olefin is selected from at least two of 1-butene, 1-hexene, and 1-octene; the liquid material A and the liquid material B are the same or different, and each independently comprises the α-olefin and an inert condensing agent; the mass flow rate ratio of the liquid material A to the liquid material B is 1:(2 to 50).

[0018] According to some embodiments of the present invention, the inert condensing agent is selected from C3-C10 saturated straight-chain or branched alkanes, C3-C10 cycloalkanes; further preferably, the inert condensing agent is selected from C4-C6 saturated straight-chain or branched alkanes, C4-C6 cycloalkanes; even more preferably, the inert condensing agent is selected from at least one of isopentane, n-pentane, n-hexane, cyclohexane and n-heptane.

[0019] According to some embodiments of the present invention, the catalyst includes a main catalyst and a co-catalyst; preferably, the main catalyst is selected from at least one of a Ziegler-Natta catalyst, a metallocene catalyst, a chromium-based catalyst, and a transition metal catalyst; the co-catalyst is selected from at least one of modified methylaluminoxane (commercially available), diethylaluminum monochloride, diisobutylaluminum monochloride, sesquiethylaluminum monochloride, diisobutylaluminum, ethylaluminum dichloride, trimethylaluminum, methylaluminoxane, triethylaluminum, triisobutylaluminum, trioctylaluminum, diethylaluminum monohydrogen and diisobutylaluminum monohydrogen.

[0020] According to some embodiments of the present invention, the gas phase material further comprises at least two of ethylene, 1-butene, 1-hexene, 1-octene, an inert gas, and an optional molecular weight regulator; preferably, the inert gas is selected from at least one of nitrogen, hexane, ethane, and propane.

[0021] According to some embodiments of the present invention, the preparation method also includes allowing the unreacted reaction raw gas to flow out from the top outlet of the fluidized bed reactor as circulating gas, and after compression, heat exchange, and gas-liquid separation, liquid material A, liquid material B, and gas material containing ethylene are obtained again and enter the fluidized bed reactor.

[0022] According to some embodiments of the present invention, the unreacted reaction raw gas comes from unreacted liquid material A, unreacted liquid material B, and unreacted gaseous material containing ethylene; the unreacted reaction raw gas includes ethylene, 1-butene, 1-hexene, 1-octene, an inert condensing agent and an optional molecular weight regulator; the molecular weight regulator is preferably hydrogen.

[0023] According to some embodiments of the present invention, the ratio of the mass flow rate of the liquid phase material A to the mass flow rate of the circulating gas is 0.005 to 0.2.

[0024] According to some embodiments of the present invention, in the circulating gas, the molar ratio of 1-butene / ethylene is 0.01-0.8; the molar ratio of 1-hexene / ethylene is 0-0.03; the molar ratio of 1-octene / ethylene is 0.001-0.05; the molar ratio of molecular weight regulator / ethylene is 0-0.8; and the molar content of inert condensing agent is 5%-25%.

[0025] According to some embodiments of the present invention, the injection position of the liquid material A is at a height of 0.2D to 4D above the distribution plate of the fluidized bed reactor, wherein D is the inner diameter of the fluidized bed reactor, and the injection position of the liquid material A includes at least one liquid injection pipeline.

[0026] According to some embodiments of the present invention, the reaction conditions include: a pressure of 1.8 MPa to 2.5 MPa, a reaction temperature of 40° C. to 90° C., and a superficial fluidizing gas velocity of 0.55 m / s to 0.75 m / s.

[0027] The third aspect of the present invention provides a system for preparing the above-mentioned ethylene and α-olefin multi-polymer, comprising: a fluidized bed reactor, a compression unit, a heat exchange unit, a gas-liquid separation unit, a condensate storage unit, and a catalyst feeding unit;

[0028] A distribution plate is provided in the fluidized bed reactor;

[0029] The top outlet of the fluidized bed reactor is connected to a compression unit through a pipeline, and the compression unit is used to pressurize the circulating gas;

[0030] The outlet of the compression unit is connected to a heat exchange unit through a pipeline, and the heat exchange unit is used to cool the circulating gas compressed by the compression unit;

[0031] The outlet of the heat exchanger is connected to the gas-liquid separation unit through a pipeline, and the gas-liquid separation unit is used to separate the circulating gas cooled by the heat exchange unit;

[0032] The liquid phase outlet of the gas-liquid separation unit is connected to the condensate storage unit through a pipeline, and the condensate storage unit introduces the stored liquid phase material into the fluidized bed reactor from different positions of the side wall above the distribution plate of the fluidized bed reactor through a feed pump; the gas phase outlet of the gas-liquid separation unit is connected to the bottom inlet of the fluidized bed reactor through a pipeline, and the gas phase material and the remaining liquid phase material are injected;

[0033] The catalyst is added into the fluidized bed reactor from a catalyst feeding unit through a catalyst feeding pipeline;

[0034] The ethylene and α-olefin multipolymer is discharged from the fluidized bed reactor through a discharge pipeline.

[0035] A fourth aspect of the present invention provides a use of the above-mentioned ethylene and α-olefin multi-polymer in the preparation of photovoltaic adhesive films.

[0036] Beneficial effects:

[0037] The invention forms a gas-liquid-solid three-phase region containing atomized liquid droplets and wet particles by spraying liquid phase materials in a fluidized bed reactor; in the region, the concentrations of 1-octene, 1-butene and 1-hexene are high, the concentrations of ethylene and hydrogen are low, and the mass transfer rate of the comonomer is fast; relatively speaking, the concentrations of 1-octene, 1-butene and 1-hexene in the traditional gas phase polymerization mode are low, the concentrations of ethylene and hydrogen are high, and the mass transfer rate of the comonomer is relatively slow; therefore, in the gas-liquid-solid three-phase region, the invention can generate a polyethylene component with high molecular weight, high 1-octene content and high branching degree, so that the density, crystallinity and haze of the final product are reduced and the transmittance is increased; at the same time, the catalyst activity is high and the residual ash is small, so that the volume resistivity of the product is reduced; based on the principle and method, the invention can provide an ethylene and alpha-olefin multi-copolymer with low haze, high transmittance and high volume resistivity, which is comparable to an ethylene-octene copolymer POE (density 0.86-0.89 g / cm 3 ) has a higher density; compared with ordinary linear low-density polyethylene LLDPE (crystallinity 35% to 65%), it has a lower crystallinity.

[0038] The present invention provides a method and system for producing ethylene and alpha-olefin multipolymers in a fluidized bed reactor. By controlling the ratio of the mass flow rate of a liquid phase material A entering the fluidized bed reactor to the mass flow rate of a circulating gas, as well as the molar ratio of 1-butene / ethylene, the molar ratio of 1-hexene / ethylene, the molar ratio of 1-octene / ethylene, the molar ratio of a molecular weight regulator / ethylene, the molar content of an inert condensing agent and the injection position of the liquid phase material A in the circulating gas, the ethylene and alpha-olefin multipolymers with low haze, high light transmittance and high volume resistivity are obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the production system of the ethylene and α-olefin multi-polymer of the present invention;

[0040] Figure 1 In the figure, 1-fluidized bed reactor, 2-distribution plate, 3-compression unit, 4-heat exchange unit, 5-gas-liquid separation unit, 6-condensate storage unit, 7-feed pump, 8-catalyst feed unit, 9-circulation pipeline, 10-fluid pipeline, 11-bottom inlet of fluidized bed reactor, 12-catalyst feed pipeline, 13-ethylene and α-olefin multipolymer discharge pipeline, 14-ethylene monomer feed pipeline, 15-molecular weight regulator feed pipeline, 16-1-butene, 1-hexene, 1-octene monomer feed pipeline, 17-inert condensing agent feed pipeline.

[0041] Figure 2 It is the DSC melting curve of the ethylene and α-olefin multipolymer prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with the embodiments, but the present invention is not limited by these embodiments.

[0043] The weight average molecular weight and molecular weight distribution index of the ethylene and α-olefin multipolymer prepared in the embodiment of the present invention are measured by gel permeation chromatography (GPC) Polymer Laboratories PL-220 instrument; the column and the rotating cell are operated at 140°C; the solvent is 1,2,4-trichlorobenzene, and the concentration of the ethylene and α-olefin multipolymer is 3‰; the injection volume is 100uL, and the flow rate is 1.0mL / min.

[0044] The haze of the ethylene and α-olefin multipolymer prepared in the examples of the present invention is measured according to GB / T2410.

[0045] The light transmittance of the ethylene and α-olefin multipolymer prepared in the examples of the present invention is measured according to GB / T 2410.

[0046] The volume resistivity of the ethylene and α-olefin multipolymer prepared in the examples of the present invention is measured according to GB / T1410.

[0047] The tensile strength at break of the ethylene and α-olefin multi-polymer prepared in the examples of the present invention is measured according to GB / T1040.

[0048] The dart impact breakage quality of the ethylene and α-olefin multi-polymer prepared in the examples of the present invention is measured according to GB / T9639.

[0049] The melt index of the ethylene and α-olefin multipolymer prepared in the embodiment of the present invention is measured according to GB / T3682.

[0050] The density of the ethylene and α-olefin multi-polymer prepared in the examples of the present invention is measured according to the GB / T 1033 method.

[0051] The melting point and crystallinity of the ethylene and α-olefin multipolymer prepared in the embodiment of the present invention are determined by differential scanning calorimetry (DSC); the specific method is: under a nitrogen atmosphere, the temperature is raised from room temperature to 160°C at 10°C / min, and the temperature is kept constant for 3min to eliminate the thermal history; then the temperature is lowered to 30°C at 10°C / min; then the temperature is raised from 30°C to 160°C at 10°C / min to obtain a melting curve, and the melting point and melting enthalpy are recorded to calculate the crystallinity.

[0052] Reference Figure 1 , the fresh gas materials required for the reaction enter the gas circulation pipeline 9 from the ethylene monomer feed pipeline 14, the molecular weight regulator enters the gas circulation pipeline 9 from the molecular weight regulator feed pipeline 15, the comonomer enters the gas circulation pipeline 9 from the 1-butene, 1-hexene, 1-octene monomer feed pipeline 16, the inert condensing agent enters the gas circulation pipeline 9 from the inert condensing agent feed pipeline 17, the catalyst intermittently or continuously enters the fluidized bed reactor 1 from the catalyst feed unit 8 through the catalyst feed pipeline 12, and the ethylene and α-olefin multipolymer product intermittently or continuously flows out from the ethylene and α-olefin multipolymer discharge pipeline 13;

[0053] Among them, the reacted gas material flows out from the top of the fluidized bed reactor 1 into the gas circulation pipeline 9, enters the gas-liquid separation unit 5 after passing through the compression unit 3 and the heat exchange unit 4, and the gas-liquid separation unit 5 separates all or part of the liquid phase material and enters the condensate storage unit 6, and then is introduced into the bed layer of the fluidized bed reactor 1 from different positions of the side wall above the distribution plate 2 of the fluidized bed reactor 1 through the feed pump 7, and the unseparated material enters the fluidized bed reactor 1 through the bottom inlet 11 of the fluidized bed reactor 1.

[0054] Example 1

[0055] This embodiment provides a method for preparing a copolymer of ethylene and α-olefin.

[0056] exist Figure 1In the production system shown, a catalytic system including a Ziegler-Natta catalyst and a triethylaluminum co-catalyst is used to carry out a multi-component copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene, wherein the reaction temperature is 85°C, the reaction pressure is 2.3MPa, and the superficial fluidization gas velocity is 0.66m / s. After the circulating gas passes through a compression unit, a heat exchange unit and a gas-liquid separation unit, a portion of the liquid phase material (referred to as liquid phase material A) containing components such as 1-butene, 1-hexene, 1-octene, isopentane, etc. enters from the side wall liquid feed port of the fluidized bed reactor, and the remaining liquid phase material (referred to as liquid phase material B) is mixed with a gas phase material containing components such as ethylene, nitrogen, hydrogen, 1-butene, 1-hexene, 1-octene, isopentane, etc., and enters from the bottom inlet of the fluidized bed reactor, and after contacting with the main catalyst and the co-catalyst in the fluidized bed reactor, a copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene occurs.

[0057] The mass flow ratio of liquid material A to liquid material B is 1:3; the ratio of the mass flow of liquid material A to the total mass flow of circulating gas is 0.07; in the circulating gas, the molar ratio of 1-butene / ethylene is 0.30, the molar ratio of 1-hexene / ethylene is 0.008, the molar ratio of 1-octene / ethylene is 0.008, the molar ratio of molecular weight regulator (hydrogen) / ethylene is 0.12, and the molar content of inert condensing agent is 9%. The injection position of liquid material A is at a height of 1.5D above the distribution plate of the fluidized bed reactor, wherein D is the inner diameter of the fluidized bed reactor, and the injection position of the liquid material A includes a liquid injection pipeline.

[0058] The density of the ethylene and α-olefin copolymer obtained in this example is 0.912 g / cm 3 , melt index is 0.70g / 10min, crystallinity is 32%, weight average molecular weight is 80000, molecular weight distribution index is 3.5, haze is 6.4%, light transmittance is 88%, volume resistivity is 5.8×10 17 Ω·cm, tensile strength at break is 25MPa, and the mass of the dart impact damage is 215g; the DSC melting curve is as follows Figure 2 As shown, the temperature range of the first melting peak T1 is 110°C ~ 128°C, the temperature range of the second melting peak T2 is 90°C ~ 110°C; the peak area ratio of the second melting peak T2 to the first melting peak T1 is 0.1, it can be seen that the melting point of the obtained ethylene and α-olefin multipolymer is 122°C.

[0059] Example 2

[0060] This embodiment provides a copolymer of ethylene and α-olefin.

[0061] exist Figure 1In the production system shown, a catalytic system including a Ziegler-Natta catalyst and a triethylaluminum co-catalyst is used to carry out a multi-component copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene, wherein the reaction temperature is 85°C, the reaction pressure is 2.3MPa, and the superficial fluidization gas velocity is 0.66m / s. After the circulating gas passes through a compression unit, a heat exchange unit and a gas-liquid separation unit, a portion of the liquid phase material (referred to as liquid phase material A) containing components such as 1-butene, 1-hexene, 1-octene, isopentane, etc. enters from the side wall liquid feed port of the fluidized bed reactor, and the remaining liquid phase material (referred to as liquid phase material B) is mixed with a gas phase material containing components such as ethylene, nitrogen, hydrogen, 1-butene, 1-hexene, 1-octene, isopentane, etc., and enters from the bottom inlet of the fluidized bed reactor, and after contacting with the main catalyst and the co-catalyst in the fluidized bed reactor, a copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene occurs.

[0062] The mass flow ratio of liquid material A to liquid material B is 1:3; the ratio of the mass flow of liquid material A to the total mass flow of circulating gas is 0.09; in the circulating gas, the molar ratio of 1-butene / ethylene is 0.32, the molar ratio of 1-hexene / ethylene is 0.010, the molar ratio of 1-octene / ethylene is 0.009, the molar ratio of molecular weight regulator (hydrogen) / ethylene is 0.10, and the molar content of inert condensing agent is 9%. The injection position of liquid material A is at a height of 1.5D above the distribution plate of the fluidized bed reactor, wherein D is the inner diameter of the fluidized bed reactor, and the injection position of the liquid material A includes a liquid injection pipeline.

[0063] The density of the ethylene and α-olefin multipolymer obtained in Example 1 is 0.909 g / cm 3 , melt index is 0.60g / 10min, crystallinity is 29%, weight average molecular weight is 95000, molecular weight distribution index is 3.3, haze is 5.6%, light transmittance is 90%, volume resistivity is 6.0×10 17 Ω·cm, the tensile strength at break is 26 MPa, and the dart impact breakage mass is 219 g; in the DSC melting curve, the temperature range of the first melting peak T1 is 105°C to 130°C, and the temperature range of the second melting peak T2 is 90°C to 105°C; the peak area ratio of the second melting peak T2 to the first melting peak T1 is 0.17, and it can be seen that the melting point of the obtained ethylene and α-olefin multipolymer is 121°C.

[0064] Example 3

[0065] This embodiment provides a copolymer of ethylene and α-olefin.

[0066] exist Figure 1In the production system shown, a catalytic system including a metallocene catalyst and a methylaluminoxane co-catalyst is used to carry out a multi-component copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene, wherein the reaction temperature is 85°C, the reaction pressure is 2.3MPa, and the superficial fluidization gas velocity is 0.66m / s. After the circulating gas passes through the compression unit, the heat exchange unit and the gas-liquid separation unit, a portion of the liquid phase material (referred to as liquid phase material A) containing components such as 1-butene, 1-hexene, 1-octene, isopentane, etc. enters from the liquid feed port on the side wall of the fluidized bed reactor, and the remaining liquid phase material (referred to as liquid phase material B) is mixed with the gas phase material containing components such as ethylene, nitrogen, hydrogen, 1-butene, 1-hexene, 1-octene, isopentane, etc., and enters from the bottom inlet of the fluidized bed reactor, and after contacting with the main catalyst and the co-catalyst in the fluidized bed reactor, the copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene occurs.

[0067] The mass flow ratio of liquid material A to liquid material B is 1:3; the ratio of the mass flow of liquid material A to the total mass flow of circulating gas is 0.09; in the circulating gas, the molar ratio of 1-butene / ethylene is 0.32, the molar ratio of 1-hexene / ethylene is 0.009, the molar ratio of 1-octene / ethylene is 0.009, the molar ratio of molecular weight regulator (hydrogen) / ethylene is 0.10, and the molar content of inert condensing agent is 9%. The injection position of liquid material A is at a height of 1.5D above the distribution plate of the fluidized bed reactor, wherein D is the inner diameter of the fluidized bed reactor, and the injection position of the liquid material A includes a liquid injection pipeline.

[0068] The density of the ethylene and α-olefin copolymer obtained in this example is 0.895 g / cm 3 , melt index is 0.66g / 10min, crystallinity is 22%, weight average molecular weight is 88000, molecular weight distribution index is 3.0, haze is 5.0%, light transmittance is 94%, volume resistivity is 9.0×10 17 Ω·cm, the tensile breaking strength is 25 MPa, and the dart impact breakage mass is 230 g; in the DSC melting curve, the temperature range of the first melting peak T1 is 105℃~127℃, and the temperature range of the second melting peak T2 is 90℃~105℃; the peak area ratio of the second melting peak T2 to the first melting peak T1 is 0.20, and it can be seen that the melting point of the obtained ethylene and α-olefin multipolymer is 120.3℃.

[0069] Example 4

[0070] This embodiment provides a copolymer of ethylene and α-olefin.

[0071] exist Figure 1In the production system shown, a catalytic system including a Ziegler-Natta catalyst and a triethylaluminum co-catalyst is used to carry out a multi-component copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene, wherein the reaction temperature is 85°C, the reaction pressure is 2.3MPa, and the superficial fluidization gas velocity is 0.66m / s. After the circulating gas passes through a compression unit, a heat exchange unit and a gas-liquid separation unit, a portion of the liquid phase material (referred to as liquid phase material A) containing components such as 1-butene, 1-hexene, 1-octene, isopentane, etc. enters from the side wall liquid feed port of the fluidized bed reactor, and the remaining liquid phase material (referred to as liquid phase material B) is mixed with a gas phase material containing components such as ethylene, nitrogen, hydrogen, 1-butene, 1-hexene, 1-octene, isopentane, etc., and enters from the bottom inlet of the fluidized bed reactor, and after contacting with the main catalyst and the co-catalyst in the fluidized bed reactor, a copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene occurs.

[0072] The mass flow ratio of liquid material A to liquid material B is 1:3; the ratio of the mass flow of liquid material A to the total mass flow of circulating gas is 0.09; in the circulating gas, the molar ratio of 1-butene / ethylene is 0.33, the molar ratio of 1-hexene / ethylene is 0.014, the molar ratio of 1-octene / ethylene is 0.012, the molar ratio of molecular weight regulator (hydrogen) / ethylene is 0.09, and the molar content of inert condensing agent is 12%. The injection position of liquid material A is at a height of 1.5D above the distribution plate of the fluidized bed reactor, wherein D is the inner diameter of the fluidized bed reactor, and the injection position of the liquid material A includes a liquid injection pipeline.

[0073] The density of the ethylene and α-olefin multipolymer obtained in this example is 0.900 g / cm 3 , melt index is 0.58g / 10min, crystallinity is 23%, weight average molecular weight is 96000, molecular weight distribution index is 4.0, haze is 5.5%, light transmittance is 92%, volume resistivity is 6.5×10 17 Ω·cm, the tensile strength at break is 22 MPa, and the dart impact breakage mass is 218 g; in the DSC melting curve, the temperature range of the first melting peak T1 is 105°C to 128°C, and the temperature range of the second melting peak T2 is 90°C to 105°C; the peak area ratio of the second melting peak T2 to the first melting peak T1 is 0.19, and it can be seen that the melting point of the obtained ethylene and α-olefin multipolymer is 120.6°C.

[0074] Example 5

[0075] This embodiment provides a copolymer of ethylene and α-olefin.

[0076] exist Figure 1In the production system shown, a catalytic system including a Ziegler-Natta catalyst and a triethylaluminum co-catalyst is used to carry out a multi-component copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene, wherein the reaction temperature is 85°C, the reaction pressure is 2.3MPa, and the superficial fluidization gas velocity is 0.66m / s. After the circulating gas passes through a compression unit, a heat exchange unit and a gas-liquid separation unit, a portion of the liquid phase material (referred to as liquid phase material A) containing components such as 1-butene, 1-hexene, 1-octene, isopentane, etc. enters from the side wall liquid feed port of the fluidized bed reactor, and the remaining liquid phase material (referred to as liquid phase material B) is mixed with a gas phase material containing components such as ethylene, nitrogen, hydrogen, 1-butene, 1-hexene, 1-octene, isopentane, etc., and enters from the bottom inlet of the fluidized bed reactor, and after contacting with the main catalyst and the co-catalyst in the fluidized bed reactor, a copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene occurs.

[0077] The mass flow ratio of liquid material A to liquid material B is 1:3; the ratio of the mass flow of liquid material A to the total mass flow of circulating gas is 0.09; in the circulating gas, the molar ratio of 1-butene / ethylene is 0.33, the molar ratio of 1-hexene / ethylene is 0.014, the molar ratio of 1-octene / ethylene is 0.012, the molar ratio of molecular weight regulator (hydrogen) / ethylene is 0.09, and the molar content of inert condensing agent is 12%. The injection position of liquid material A is at a height of 3D above the distribution plate of the fluidized bed reactor, wherein D is the inner diameter of the fluidized bed reactor, and the injection position of the liquid material A includes a liquid injection pipeline.

[0078] The density of the ethylene and α-olefin copolymer obtained in this example is 0.910 g / cm 3 , melt index is 0.58g / 10min, crystallinity is 35%, weight average molecular weight is 96000, molecular weight distribution index is 3.8, haze is 7.0%, light transmittance is 89%, volume resistivity is 6.5×10 17 Ω·cm, the tensile strength at break is 27 MPa, and the dart impact breakage mass is 209 g; in the DSC melting curve, the temperature range of the first melting peak T1 is 110°C to 130°C, and the temperature range of the second melting peak T2 is 100°C to 110°C; the peak area ratio of the second melting peak T2 to the first melting peak T1 is 0.12, and it can be seen that the melting point of the obtained ethylene and α-olefin multipolymer is 122°C.

[0079] Example 6

[0080] This embodiment provides a copolymer of ethylene and α-olefin.

[0081] exist Figure 1In the production system shown, a catalytic system including a Ziegler-Natta catalyst and a triethylaluminum co-catalyst is used to carry out a multi-component copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene, wherein the reaction temperature is 85°C, the reaction pressure is 2.3MPa, and the superficial fluidization gas velocity is 0.66m / s. After the circulating gas passes through a compression unit, a heat exchange unit and a gas-liquid separation unit, a portion of the liquid phase material (referred to as liquid phase material A) containing components such as 1-butene, 1-hexene, 1-octene, isopentane, etc. enters from the side wall liquid feed port of the fluidized bed reactor, and the remaining liquid phase material (referred to as liquid phase material B) is mixed with a gas phase material containing components such as ethylene, nitrogen, hydrogen, 1-butene, 1-hexene, 1-octene, isopentane, etc., and enters from the bottom inlet of the fluidized bed reactor, and after contacting with the main catalyst and the co-catalyst in the fluidized bed reactor, a copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene occurs.

[0082] The mass flow ratio of liquid material A to liquid material B is 1:3; the ratio of the mass flow of liquid material A to the total mass flow of circulating gas is 0.11; in the circulating gas, the molar ratio of 1-butene / ethylene is 0.40, the molar ratio of 1-hexene / ethylene is 0.020, the molar ratio of 1-octene / ethylene is 0.020, the molar ratio of molecular weight regulator (hydrogen) / ethylene is 0.09, and the molar content of inert condensing agent is 12%. The injection position of liquid material A is at a height of 1.5D above the distribution plate of the fluidized bed reactor, wherein D is the inner diameter of the fluidized bed reactor, and the injection position of the liquid material A includes 2 liquid injection pipelines.

[0083] The density of the ethylene and α-olefin copolymer obtained in this example is 0.895 g / cm 3 , melt index is 0.63g / 10min, crystallinity is 21%, weight average molecular weight is 90000, molecular weight distribution index is 3.8, haze is 4.6%, light transmittance is 94%, volume resistivity is 7.0×10 17 Ω·cm, the tensile strength at break is 24 MPa, and the dart impact breakage mass is 220 g; in the DSC melting curve, the temperature range of the first melting peak T1 is 105°C to 126°C, and the temperature range of the second melting peak T2 is 90°C to 105°C; the peak area ratio of the second melting peak T2 to the first melting peak T1 is 0.13, and it can be seen that the melting point of the obtained ethylene and α-olefin multipolymer is 120°C.

[0084] Example 7

[0085] This embodiment provides a copolymer of ethylene and α-olefin.

[0086] exist Figure 1In the production system shown, a catalytic system including a metallocene catalyst and a methylaluminoxane co-catalyst is used to carry out a multi-component copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene, wherein the reaction temperature is 85°C, the reaction pressure is 2.3MPa, and the superficial fluidization gas velocity is 0.66m / s. After the circulating gas passes through the compression unit, the heat exchange unit and the gas-liquid separation unit, a portion of the liquid phase material (referred to as liquid phase material A) containing components such as 1-butene, 1-hexene, 1-octene, isopentane, etc. enters from the liquid feed port on the side wall of the fluidized bed reactor, and the remaining liquid phase material (referred to as liquid phase material B) is mixed with the gas phase material containing components such as ethylene, nitrogen, hydrogen, 1-butene, 1-hexene, 1-octene, isopentane, etc., and enters from the bottom inlet of the fluidized bed reactor, and after contacting with the main catalyst and the co-catalyst in the fluidized bed reactor, the copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene occurs.

[0087] The mass flow ratio of liquid material A to liquid material B is 1:2.5; the ratio of the mass flow of liquid material A to the total mass flow of circulating gas is 0.12; in the circulating gas, the molar ratio of 1-butene / ethylene is 0.40, the molar ratio of 1-hexene / ethylene is 0.020, the molar ratio of 1-octene / ethylene is 0.020, the molar ratio of molecular weight regulator (hydrogen) / ethylene is 0.09, and the molar content of inert condensing agent is 12%. The injection position of liquid material A is at a height of 1.5D above the distribution plate of the fluidized bed reactor, wherein D is the inner diameter of the fluidized bed reactor, and the injection position of the liquid material A includes 2 liquid injection pipelines.

[0088] The density of the ethylene and α-olefin copolymer obtained in this example is 0.890 g / cm 3 , melt index is 1.20g / 10min, crystallinity is 19%, weight average molecular weight is 79000, molecular weight distribution index is 3.0, haze is 3.5%, light transmittance is 96%, volume resistivity is 10.0×10 17 Ω·cm, the tensile breaking strength is 22 MPa, and the dart impact breakage mass is 252 g; in the DSC melting curve, the temperature range of the first melting peak T1 is 105℃~126℃, and the temperature range of the second melting peak T2 is 90℃~105℃; the peak area ratio of the second melting peak T2 to the first melting peak T1 is 0.20, and it can be seen that the melting point of the obtained ethylene and α-olefin multipolymer is 119.5℃.

[0089] Comparative Example 1

[0090] This comparative example provides a copolymer of ethylene and α-olefin.

[0091] The method described in Example 1 was followed, except that Figure 1In the production system shown, a catalytic system including a Ziegler-Natta catalyst and a triethylaluminum co-catalyst is used to carry out a ternary copolymerization reaction of ethylene, 1-butene and 1-hexene, wherein the reaction temperature is 85°C, the reaction pressure is 2.3MPa, and the superficial fluidizing gas velocity is 0.66m / s. After the circulating gas passes through a compression unit, a heat exchange unit and a gas-liquid separation unit, a portion of the liquid phase material (referred to as liquid phase material A) containing components such as 1-butene, 1-hexene, and isopentane enters from the side wall liquid feed port of the fluidized bed reactor, and the remaining liquid phase material (referred to as liquid phase material B) is mixed with a gas phase material containing components such as ethylene, nitrogen, hydrogen, 1-butene, 1-hexene, and isopentane, and enters from the bottom inlet of the fluidized bed reactor, and after contacting with the main catalyst and the co-catalyst in the fluidized bed reactor, a copolymerization reaction of ethylene, 1-butene, and 1-hexene occurs.

[0092] The mass flow ratio of liquid material A to liquid material B is 1:3; the ratio of the mass flow of liquid material A to the total mass flow of circulating gas is 0.07; in the circulating gas, the molar ratio of 1-butene / ethylene is 0.30, the molar ratio of 1-hexene / ethylene is 0.04, the molar ratio of molecular weight regulator (hydrogen) / ethylene is 0.12, and the molar content of inert condensing agent is 9%. The injection position of liquid material A is at a height of 1.5D above the distribution plate of the fluidized bed reactor, wherein D is the inner diameter of the fluidized bed reactor, and the injection position of the liquid material A includes a liquid injection pipeline.

[0093] The density of the ethylene and α-olefin multipolymer obtained in this comparative example is 0.918 g / cm 3 , melt index is 1.0g / 10min, crystallinity is 32%, weight average molecular weight is 85000, molecular weight distribution index is 3.4, haze is 12%, light transmittance is 80%, volume resistivity is 6.0×10 17 Ω·cm, the tensile strength at break is 20 MPa, and the dart impact damage mass is 150 g; the DSC melting curve only contains the first melting peak T1, the temperature range is 90℃~135℃, and the melting point of the obtained ethylene and α-olefin multipolymer is 126℃.

[0094] Comparative Example 2

[0095] This comparative example provides a copolymer of ethylene and α-olefin.

[0096] The method described in Example 1 was followed, except that Figure 1In the production system shown, a catalytic system including a Ziegler-Natta catalyst and a triethylaluminum co-catalyst is used to carry out a multi-component copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene, wherein the reaction temperature is 85°C, the reaction pressure is 2.3MPa, and the superficial fluidization gas velocity is 0.66m / s. After the circulating gas passes through a compression unit, a heat exchange unit and a gas-liquid separation unit, a portion of the liquid phase material (referred to as liquid phase material A) containing components such as 1-butene, 1-hexene, 1-octene, isopentane, etc. enters from the side wall liquid feed port of the fluidized bed reactor, and the remaining liquid phase material (referred to as liquid phase material B) is mixed with a gas phase material containing components such as ethylene, nitrogen, hydrogen, 1-butene, 1-hexene, 1-octene, isopentane, etc., and enters from the bottom inlet of the fluidized bed reactor, and after contacting with the catalyst and the co-catalyst in the fluidized bed reactor, a copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene occurs.

[0097] The mass flow ratio of liquid material A to liquid material B is 1:10; the ratio of the mass flow of liquid material A to the total mass flow of circulating gas is 0.01, and in the circulating gas, the molar ratio of 1-butene / ethylene is 0.30, the molar ratio of 1-hexene / ethylene is 0.009, the molar ratio of 1-octene / ethylene is 0.008, the molar ratio of molecular weight regulator (hydrogen) / ethylene is 0.12, and the molar content of inert condensing agent is 9%. The injection position of liquid material A is at a height of 1.5D above the distribution plate of the fluidized bed reactor, wherein D is the inner diameter of the fluidized bed reactor, and the injection position of the liquid material A includes at least one liquid injection pipeline.

[0098] The density of the ethylene and α-olefin multipolymer obtained in this comparative example is 0.925 g / cm 3 , melt index is 1.2g / 10min, crystallinity is 40%, weight average molecular weight is 83000, molecular weight distribution index is 3.2, haze is 15%, light transmittance is 80%, volume resistivity is 6.0×10 17 Ω·cm, the tensile strength at break is 25 MPa, and the dart impact breakage mass is 180 g; the DSC melting curve only contains the first melting peak T1, the temperature range is 90℃~135℃, and the melting point of the obtained ethylene and α-olefin multipolymer is 126℃.

[0099] Comparative Example 3

[0100] This comparative example provides a copolymer of ethylene and α-olefin.

[0101] The method described in Example 1 was followed, except that Figure 1In the production system shown, a catalytic system including a Ziegler-Natta catalyst and a triethylaluminum co-catalyst is used to carry out a multi-component copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene, wherein the reaction temperature is 85°C, the reaction pressure is 2.3MPa, and the superficial fluidization gas velocity is 0.66m / s. After the circulating gas passes through a compression unit, a heat exchange unit and a gas-liquid separation unit, a portion of the liquid phase material (referred to as liquid phase material A) containing components such as 1-butene, 1-hexene, 1-octene, isopentane, etc. enters from the side wall liquid feed port of the fluidized bed reactor, and the remaining liquid phase material (referred to as liquid phase material B) is mixed with a gas phase material containing components such as ethylene, nitrogen, hydrogen, 1-butene, 1-hexene, 1-octene, isopentane, etc., and enters from the bottom inlet of the fluidized bed reactor, and after contacting with the catalyst and the co-catalyst in the fluidized bed reactor, a copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene occurs.

[0102] The mass flow ratio of liquid material A to liquid material B is 1:1.7; the ratio of the mass flow of liquid material A to the total mass flow of circulating gas is 0.13; in the circulating gas, the molar ratio of 1-butene / ethylene is 0.30, the molar ratio of 1-hexene / ethylene is 0.010, the molar ratio of 1-octene / ethylene is 0.008, the molar ratio of molecular weight regulator (hydrogen) / ethylene is 0.10, and the molar content of inert condensing agent is 9%. The injection position of liquid material A is at a height of 1.5D above the distribution plate of the fluidized bed reactor, wherein D is the inner diameter of the fluidized bed reactor, and the injection position of the liquid material A includes at least one liquid injection pipeline.

[0103] The density of the ethylene and α-olefin multipolymer obtained in this comparative example is 0.895 g / cm 3 , melt index is 1.0g / 10min, crystallinity is 25%, weight average molecular weight is 85000, molecular weight distribution index is 4.5, haze is 10%, light transmittance is 87%, volume resistivity is 6.0×10 17 Ω·cm, the tensile strength at break is 20 MPa, and the dart impact breakage mass is 175 g; the DSC melting curve only contains the first melting peak T1, the temperature range is 90℃~135℃, and the melting point of the obtained ethylene and α-olefin multipolymer is 124℃.

[0104] Comparative Example 4

[0105] This comparative example provides a copolymer of ethylene and α-olefin.

[0106] The method described in Example 1 was followed, except that Figure 1In the production system shown, a catalytic system including a Ziegler-Natta catalyst and a triethylaluminum co-catalyst is used to carry out a multi-component copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene, wherein the reaction temperature is 85°C, the reaction pressure is 2.3MPa, and the superficial fluidization gas velocity is 0.66m / s. After the circulating gas passes through a compression unit, a heat exchange unit and a gas-liquid separation unit, a portion of the liquid phase material (referred to as liquid phase material A) containing components such as 1-butene, 1-hexene, 1-octene, isopentane, etc. enters from the side wall liquid feed port of the fluidized bed reactor, and the remaining liquid phase material (referred to as liquid phase material B) is mixed with a gas phase material containing components such as ethylene, nitrogen, hydrogen, 1-butene, 1-hexene, 1-octene, isopentane, etc., and enters from the bottom inlet of the fluidized bed reactor, and after contacting with the main catalyst and the co-catalyst in the fluidized bed reactor, a copolymerization reaction of ethylene, 1-butene, 1-hexene and 1-octene occurs.

[0107] The mass flow ratio of liquid material A to liquid material B is 1:3; the ratio of the mass flow of liquid material A to the total mass flow of circulating gas is 0.12; in the circulating gas, the molar ratio of 1-butene / ethylene is 0.40, the molar ratio of 1-hexene / ethylene is 0.020, the molar ratio of 1-octene / ethylene is 0.020, the molar ratio of molecular weight regulator (hydrogen) / ethylene is 0.09, and the molar content of inert condensing agent is 12%. The injection position of liquid material A is at a height of 5D above the distribution plate of the fluidized bed reactor, wherein D is the inner diameter of the fluidized bed reactor, and the injection position of the liquid material A includes 2 liquid injection pipelines.

[0108] The density of the ethylene and α-olefin copolymer obtained in this example is 0.918 g / cm 3 , melt index is 0.63g / 10min, crystallinity is 35%, weight average molecular weight is 90000, molecular weight distribution index is 3.8, haze is 10%, light transmittance is 86%, volume resistivity is 4.0×10 17 Ω·cm, the tensile strength at break is 28 MPa, and the dart impact damage mass is 200 g; the DSC melting curve only includes the first melting peak T1, the temperature range is 100°C to 135°C, and the melting point of the obtained ethylene and α-olefin multipolymer is 123°C.

[0109] It can be seen from the above Examples 1-7 and Comparative Examples 1-4 that the method for producing ethylene and α-olefin multipolymers provided by the present invention can produce an ethylene and α-olefin multipolymer product with low haze, high transmittance and high volume resistivity in a fluidized bed reactor, which has a higher density than POE products with the same haze or transmittance; the ethylene and α-olefin multipolymer product and its production method have important application value and a wide range of application space.

[0110] In order to further illustrate the present invention, the contents of ethylene structural units, 1-butene structural units, 1-hexene structural units and 1-octene structural units in the ethylene and α-olefin multi-polymers prepared in Examples 1-7 and Comparative Examples 1-4 were measured using a Bruker Advance 2B 400MHz 13 C-NMR was measured and the statistics are shown in Table 1 below.

[0111] Table 1

[0112]

[0113]

[0114] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. An ethylene and α-olefin multipolymer, characterized in that: The haze of the ethylene and α-olefin multipolymer is 1% to 7%, the light transmittance is greater than 87%, and the volume resistivity is greater than 5.0×10 17 Ω·cm, weight average molecular weight of 70000 to 130000, and crystallinity of 15% to 35%.

2. The ethylene and α-olefin multipolymer according to claim 1, characterized in that: Based on the total molar amount of the ethylene and α-olefin multi-polymer, the molar content of the ethylene structural unit in the ethylene and α-olefin multi-polymer is 80 mol% to 96 mol%, the molar content of the 1-butene structural unit is 2.0 mol% to 10 mol%, the molar content of the 1-hexene structural unit is 0 mol% to 3.5 mol%, and the molar content of the 1-octene structural unit is 0.3 mol% to 15 mol%; Preferably, the ethylene and α-olefin multipolymer comprises at least ethylene structural units, 1-butene structural units and 1-octene structural units.

3. The ethylene and α-olefin multipolymer according to claim 2, characterized in that: The DSC melting curve of the ethylene and α-olefin multipolymer includes a first melting peak T1 and a second melting peak T2; preferably, the temperature range of the first melting peak T1 is 105°C to 135°C, and the temperature range of the second melting peak T2 is 90°C to 110°C; further preferably, the peak area ratio of the second melting peak T2 to the first melting peak T1 is 0.01 to 0.

5.

4. The ethylene and α-olefin multipolymer according to any one of claims 1 to 3, characterized in that: The molecular weight distribution index of the ethylene and α-olefin multipolymer is 2 to 8, preferably 3 to 5; And / or, the density of the ethylene and α-olefin multipolymer is 0.885 g / cm 3 ~0.930g / cm 3 , preferably 0.89 g / cm 3 ~0.92g / cm 3 ; Under the conditions of temperature of 190°C and load of 2.16kg, the melt index of the ethylene and α-olefin multipolymer is 0.5g / 10min~15g / 10min, preferably 0.58g / 10min~8g / 10min; the melting point of the ethylene and α-olefin multipolymer is 80°C~130°C, preferably 100°C~125°C.

5. A method for preparing a copolymer of ethylene and α-olefin as claimed in any one of claims 1 to 4, characterized in that: The method comprises contacting a liquid material A from the side wall of a fluidized bed reactor with a liquid material B from the bottom of the fluidized bed reactor and a gaseous material containing ethylene in the presence of a catalyst to react and generate the ethylene and α-olefin multipolymer.

6. The preparation method according to claim 5, characterized in that: The α-olefin is selected from at least two of 1-butene, 1-hexene, and 1-octene; the liquid material A and the liquid material B are the same or different, and each independently comprises the α-olefin and an inert condensing agent; the mass flow rate ratio of the liquid material A to the liquid material B is 1:(2-50); Preferably, the inert condensing agent is selected from C3-C10 saturated straight-chain or branched alkanes, C3-C10 cycloalkanes; further preferably, the inert condensing agent is selected from C4-C6 saturated straight-chain or branched alkanes, C4-C6 cycloalkanes; further preferably, the inert condensing agent is selected from at least one of isopentane, n-pentane, n-hexane, cyclohexane, and n-heptane; And / or, the catalyst comprises a main catalyst and a co-catalyst; preferably, the main catalyst is selected from at least one of a Ziegler-Natta catalyst, a metallocene catalyst, a chromium-based catalyst, and a transition metal catalyst; the co-catalyst is selected from at least one of modified methylaluminoxane, diethylaluminum monochloride, diisobutylaluminum monochloride, sesquiethylaluminum monochloride, diisobutylaluminum, diethylaluminum dichloride, trimethylaluminum, methylaluminoxane, triethylaluminum, triisobutylaluminum, trioctylaluminum, diethylaluminum monohydrogen and diisobutylaluminum monohydrogen; And / or, the gas phase material includes at least two of ethylene, 1-butene, 1-hexene, 1-octene, an inert gas, and an optional molecular weight regulator; preferably, the inert gas is selected from at least one of nitrogen, hexane, ethane, and propane.

7. The preparation method according to claim 6, characterized in that: The preparation method further comprises: unreacted reaction raw material gas is discharged from the top outlet of the fluidized bed reactor as circulating gas, and after compression, heat exchange, and gas-liquid separation, liquid phase material A, liquid phase material B, and gas phase material containing ethylene are obtained again, and enter the fluidized bed reactor; Preferably, the unreacted reaction raw gas comes from unreacted liquid phase material A, unreacted liquid phase material B, and unreacted gas phase material containing ethylene; the unreacted reaction raw gas includes ethylene, 1-butene, 1-hexene, 1-octene, an inert condensing agent and an optional molecular weight regulator; the molecular weight regulator is preferably hydrogen; Further preferably, the ratio of the mass flow rate of the liquid phase material A to the mass flow rate of the circulating gas is 0.005 to 0.2; More preferably, in the circulating gas, the molar ratio of 1-butene / ethylene is 0.01 to 0.8; the molar ratio of 1-hexene / ethylene is 0 to 0.03; the molar ratio of 1-octene / ethylene is 0.001 to 0.05; the molar ratio of molecular weight regulator / ethylene is 0 to 0.8; and the molar content of inert condensing agent is 5% to 25%.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The injection position of the liquid phase material A is at a height of 0.2D to 4D above the distribution plate of the fluidized bed reactor, wherein D is the inner diameter of the fluidized bed reactor, and the injection position of the liquid phase material A includes at least one liquid injection pipeline; And / or, the reaction conditions include: pressure of 1.8 MPa to 2.5 MPa, reaction temperature of 40° C. to 90° C., and superficial fluidizing gas velocity of 0.55 m / s to 0.75 m / s.

9. A system for preparing the ethylene and α-olefin multipolymer according to claims 1 to 4 or the ethylene and α-olefin multipolymer prepared by the preparation method according to any one of claims 5 to 7, characterized in that: The system comprises: a fluidized bed reactor (1), a compression unit (3), a heat exchange unit (4), a gas-liquid separation unit (5), a condensate storage unit (6), and a catalyst feeding unit (8); The fluidized bed reactor (1) is provided with a distribution plate (2); The top outlet of the fluidized bed reactor (1) is connected to a compression unit (3) via a pipeline (9), and the compression unit (3) is used to pressurize the circulating gas; The outlet of the compression unit (3) is connected to the heat exchange unit (4) via a pipeline (9), and the heat exchange unit (4) is used to cool the circulating gas compressed by the compression unit (3); The outlet of the heat exchanger (4) is connected to the gas-liquid separation unit (5) through a pipeline (9), and the gas-liquid separation unit (5) is used to separate the circulating gas after being cooled by the heat exchange unit (4); The liquid phase outlet of the gas-liquid separation unit (5) is connected to the condensate storage unit (6) via a pipeline (9), and the condensate storage unit (6) introduces the stored liquid phase material into the fluidized bed reactor (1) from different positions on the side wall above the distribution plate (2) of the fluidized bed reactor (1) via a feed pump (7); the gas phase outlet of the gas-liquid separation unit (5) is connected to the bottom inlet (11) of the fluidized bed reactor (1) via a pipeline (9), and the gas phase material and the remaining liquid phase material are injected; The catalyst is fed into the fluidized bed reactor (1) from a catalyst feeding unit (8) via a catalyst feeding pipeline (12); The ethylene and α-olefin multipolymer is discharged from the fluidized bed reactor (1) through the discharge line (13).

10. Use of the ethylene and α-olefin multipolymer as claimed in claims 1 to 4 or the ethylene and α-olefin multipolymer prepared by the preparation method according to any one of claims 5 to 7 in preparing photovoltaic adhesive films.

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