Ethylene polymer and method for preparing the same

Abstract

The present invention relates to an ethylene polymer and a process for preparing the same, the ethylene polymer having an average particle size of 50 to 3000 μm and a bulk density of 0.28 to 0.55 g / cm 3 and the true density is 0.930 to 0.980 g / cm 3 The melt index at 190°C and a load of 2.16 kg is 0.01-2500 g / 10 min, the crystallinity is 30-90%, the melting point is 105-147°C; the molar insertion rate of the comonomer is 0.01-5 mol%, the weight average molecular weight is 20000 g / mol-400000 g / mol, and the molecular weight distribution is 1.8-10. The preparation method includes using an alkane solvent having a boiling point of 5-55° C., or a mixed alkane solvent having a saturated vapor pressure at 20° C. of 20-150 KPa as a polymerization solvent; and carrying out a kettle type slurry polymerization on a feedstock comprising ethylene, hydrogen, and a comonomer in the presence of a polyethylene catalyst system and under conditions of a hydrogen to ethylene molar ratio of 0.01-20:1, preferably 0.015-10:1, and a hydrogen to comonomer molar ratio of 0.1-30:1, preferably 0.15-25:1, to prepare an ethylene polymer.

Description

Detailed Description of the Invention

[0001] 〔Technical Field〕 The present invention relates to a high-density ethylene polymer and a method for preparing an ethylene slurry polymerization for preparing the ethylene polymer. Specifically, the present invention relates to a high-density ethylene copolymer and a method for preparing the ethylene copolymer. The method is a tank-type slurry polymerization of a raw material containing ethylene, hydrogen gas, and a comonomer by using an alkane solvent having a boiling point of 5 to 55 ° C or a mixed alkane solvent having a saturated vapor pressure of 20 to 150 KPa at 20 ° C as a polymerization solvent under ethylene slurry polymerization conditions in the presence of a polyethylene catalyst system.

[0002] 〔Background Art〕 Polyethylene preparation methods mainly include high-pressure polymerization, gas-phase polymerization, slurry polymerization, solution polymerization, and other techniques and methods. Among them, the ethylene slurry polymerization method is one of the main methods for preparing polyethylene. This method can be divided into a loop reactor polymerization method and a stirred tank slurry polymerization method.

[0003] In the absence of a comonomer, the homopolymerization of ethylene can produce medium-density and high-density polyethylene such as ultra-high molecular weight polyethylene, ultra-high molecular weight polyethylene, and polyethylene wax. In the presence of comonomers such as propylene, 1-butene, 1-hexene, and 1-octene, ethylene copolymerizes with the comonomer to obtain medium-density and high-density polyethylene (ethylene copolymer) having excellent toughness. As the insertion rate of comonomer units in the copolymer increases, the density of the ethylene copolymer gradually decreases. At the same molar insertion rate of comonomer units, as the carbon chain of the comonomer becomes longer, the density of the ethylene copolymer significantly decreases.

[0004] Previous studies have generally shown that under comparable conditions such as the same catalyst system and similar polymerization modes, the longer the chain segments of the comonomer, the better the performance of the ethylene copolymer product. For example, the performance of a copolymer of ethylene and 1-octene is better than that of a copolymer of ethylene and 1-hexene, the performance of a copolymer of ethylene and 1-hexene is better than that of a copolymer of ethylene and 1-butene, and the performance of a copolymer of ethylene and 1-butene is better than that of a copolymer of ethylene and propylene.

[0005] However, in existing ethylene stirred-tank slurry polymerization technologies or polymerization methods, such as Mitsui Chemicals' ethylene slurry polymerization CX technology and Lyondell Basell's Hostalen technology, hexane is used as the polymerization solvent. In this case, when 1-hexene is used as the comonomer, the boiling points of hexane and 1-hexene are similar (the difference is less than 2 °C), so their separation is difficult. Therefore, ethylene stirred-tank slurry polymerization technologies or polymerization methods that use hexane as the solvent are not suitable when using 1-hexene as the polymerization comonomer, and the development of high-performance products obtained by the stirred-tank slurry polymerization technology and using 1-hexene as the comonomer is severely restricted.

[0006] On the other hand, in ethylene slurry polymerization, when using a solvent with a boiling point higher than hexane, such as n-heptane, iso-heptane, or their isomeric solvents, since the boiling point in polymerization is higher, the energy consumption for gasification and condensation is relatively high, and it is not suitable for polymerization that removes heat by gas-phase circulation condensation used in existing industrial production plants. Furthermore, the polymer powder obtained after filtration or centrifugation has a relatively high solvent content, and therefore, the cost for drying in polymerization production and post-treatment is relatively high.

[0007] In addition, the existing ethylene slurry polymerization method has a relatively low polymerization pressure, and the presence of the partial pressures of hydrogen gas and comonomer results in a lower partial pressure of ethylene. Also, when preparing an ethylene polymer with a high melt index and a low density, the activity of the polyethylene main catalyst is low, the catalyst consumption is relatively high, and the preparation cost is high.

[0008] Therefore, in the existing technology, there still remains a large room for improving the preparation of high-density ethylene polymers (ethylene copolymers) by the tank-type ethylene slurry polymerization method and the high-density ethylene polymers prepared therefrom.

[0009] 〔Summary of the Invention〕 Based on the existing technology, through extensive experiments, analysis, and detailed research, the inventors have found that by using an alkane solvent with a boiling point of 5 to 55 °C or a mixed alkane solvent with a saturated vapor pressure of 20 to 150 KPa at 20 °C as the polymerization solvent, the existing polyethylene catalyst system can be applied under ethylene slurry polymerization conditions, and comonomers widely used in existing industrial production and applications such as propylene, 1-butene, 1-hexene, and 1-octene can be used as comonomers, thereby creatively discovering that the problems of the above prior art can be effectively solved, and the present invention has been completed.

[0010] Furthermore, in the present invention, by using a low-boiling alkane solvent or a mixed alkane solvent with a high saturated vapor pressure as the polymerization solvent and an ethylene slurry polymerization method for controlling a certain proportion of hydrogen gas and comonomer, a high-density ethylene copolymer with excellent performance can be prepared without requiring a harsh polymerization reactor configuration and polymerization reaction conditions, the performance of the ethylene polymer can be adjusted within a wide range, and the production mode is flexible. Therefore, the method of the present invention is very suitable for industrial production.

[0011] Specifically, the present invention provides a high-density ethylene polymer, and the ethylene polymer has an average particle size of 50 to 3000 μm, preferably 100 to 1000 μm, and a weight-average molecular weight of 2×10 4 g / mol to 40×10 4 g / mol, preferably 5×10 4 g / mol to 30×10 4 g / mol, a molecular weight distribution of 1.8 to 10, preferably 2.0 to 8.0, a comonomer molar insertion rate of 0.01 to 5 mol%, preferably 0.05 to 2.5 mol%, and preferably a melt index at a load of 2.16 Kg at 190 °C of 0.01 to 2500 g / 10 min, preferably 0.1 to 2000 g / 10 min, more preferably 0.1 to 1000 g / 10 min, and a bulk density of 0.28 to 0.55 g / cm 3 , preferably 0.32 to 0.50 g / cm 3 and a true density of 0.930 to 0.980 g / cm 3 , preferably 0.940 to 0.970 g / cm 3 , more preferably 0.942 to 0.970 g / cm 3 , a crystallinity of 30 to 90%, preferably 40 to 80%, a melting point of 105 to 147 °C, preferably 110 to 143 °C, and a processing index in a film blowing test of 4.0 to 6.0, preferably 4.5 to 5.9, more preferably 5.0 to 5.8.

[0012] The present invention also provides a method for preparing an ethylene polymer. In the preparation method, the molar ratio of hydrogen gas to ethylene is 0.01 to 20:1, preferably 0.015 to 10:1, and the molar ratio of hydrogen gas to comonomer is 0.1 to 30:1, preferably 0.15 to 25:1, more preferably 0.2 to 23:1. In the presence of a polyethylene catalyst system, a raw material containing ethylene, hydrogen gas and comonomer is subjected to tank-type slurry polymerization using an alkane solvent having a boiling point of 5 to 55 °C or a mixed alkane solvent having a saturated vapor pressure of 20 to 150 KPa at 20 °C as a polymerization solvent.

[0013] 〔Technical Effects〕 The present invention provides a high-density ethylene polymer (ethylene copolymer). Its bulk density and true density are high; its melt index, crystallinity, melting point, comonomer molar insertion rate, weight average molecular weight, etc. have a wide range, are adjustable and controllable; its molecular weight distribution has a medium range, is adjustable and controllable; it has good subsequent processability and is very suitable for production and application in the tank-type ethylene slurry polymerization method.

[0014] According to the method for preparing the ethylene polymer of the present invention, in the slurry polymerization preparation process, a raw material containing ethylene, hydrogen gas and a comonomer is subjected to slurry polymerization using an alkane solvent with a boiling point of 5 to 55 °C or a mixed alkane solvent with a saturated vapor pressure of 20 to 150 KPa at 20 °C as a polymerization solvent to produce an ethylene polymer (polyethylene, ethylene copolymer). In the separation stage of the polymer material obtained after the polymerization reaction, it is easier to separate the solvent from comonomers such as propylene, 1-butene, 1-hexene, and 1-octene. Therefore, by this polymerization method, high-density ethylene polymers (ethylene copolymers) with different properties can be produced more efficiently. In addition, by using a specific polymerization solvent, the oligomers generated during the polymerization reaction remain in the obtained ethylene polymer, and as a result, the obtained ethylene polymer is excellent in subsequent processability.

[0015] By using the ethylene slurry polymerization method of the present invention, it becomes very easy to dry the ethylene polymer powder obtained after the completion of the polymerization. After the completion of the polymerization reaction, the product is directly filtered, and the residual solvent content in the wet polymer is less than 20% by weight, which is lower than the residual solvent content of more than 25% by weight in the wet polymer obtained according to the existing technology by using hexane as the polymerization solvent. This is very helpful for shortening the drying time of the polyethylene material and saving the cost of polyethylene post-treatment, and as a result, it facilitates the subsequent industrial application of the ethylene polymer.

[0016] In the method of the present invention, by setting the ratio of hydrogen gas and ethylene within a specific range, while polymerizing ethylene and a comonomer, an appropriate amount of oligomer is also generated. Furthermore, by using a specific polymerization solvent, the oligomer generated during the polymerization reaction can remain in the ethylene polymer, resulting in excellent processing performance of the obtained ethylene polymer.

[0017] Also, in the polymerization method of the present invention, only an alkane solvent having a boiling point of 5 to 55°C or a mixed alkane solvent having a saturated vapor pressure of 20 to 150 KPa at 20°C is used as the polymerization solvent, and there is no need to use other solvents such as a dispersant and a diluent, resulting in a simple reaction system and easy post-treatment.

[0018] 〔Detailed Description〕 Referring in detail to the present embodiment of the present invention, it should be understood that the scope of the present invention is not limited by the embodiment but is defined by the appended claims.

[0019] In the context of this specification, any item or matter not mentioned, except as explicitly stated, is directly applicable to what is known in the art without any modification. Furthermore, any of the embodiments described in this specification can be freely combined with one or more of the other embodiments described in this specification, and the resulting technical solution or technical idea is considered to be part of the original disclosure or original record of the present invention, and should not be regarded as new content not disclosed or not expected in this specification unless the combination is clearly unreasonable as believed by those skilled in the art.

[0020] In the context of the present invention, unless otherwise clearly defined or beyond the understanding of those skilled in the art, hydrocarbons or hydrocarbon-derived groups having 3 or more carbon atoms without the prefix "n-" (e.g., propyl, propyloxy, butyl, butane, butene, butenyl, and hexane) have the same meaning as those having the prefix "n-". For example, propyl is generally understood as n-propyl, and butyl is generally understood as n-butyl.

[0021] In the context of the present invention, unless otherwise specified, the physical properties of a substance (e.g., boiling point) are measured at room temperature (25 °C) and normal pressure (101325 Pa).

[0022] In the present invention, an ethylene polymer is a copolymer of ethylene and other comonomers and is sometimes referred to as polyethylene.

[0023] The inventors have conducted intensive research and found that in the polymerization method of the present invention, by using an alkane solvent having a boiling point of 5 to 55 °C or a mixed alkane solvent having a saturated vapor pressure of 20 to 150 KPa at 20 °C as the polymerization solvent, compared with the previous polymerization solvent, the specific polymerization solvent of the present invention and ethylene and olefins for copolymerization (e.g., propylene, 1-butene, 1-hexene, 1-octene) as reactants have significantly different boiling points. Therefore, the post-treatment of the obtained ethylene polymer can be carried out simply and efficiently, the residual solvent content in the obtained ethylene polymer powder is low, which is very helpful for shortening the drying time of the polyethylene material, and it is confirmed that the cost of post-treatment of the ethylene polymer powder can be saved.

[0024] By using the slurry polymerization method of the ethylene polymer of the present invention, it becomes very easy to dry the ethylene polymer powder obtained after the completion of polymerization. After the polymerization reaction is completed, the product is directly filtered, and the residual solvent content in the wet polymer is less than 20% by weight, which is lower than the residual solvent content of more than 25% by weight in the wet polymer obtained according to the existing technology by using hexane as the polymerization solvent. This is very helpful for shortening the drying time of the polyethylene material and saving the cost of polyethylene post-treatment, and as a result, it facilitates the subsequent industrial application of the ethylene polymer. Also, by using a specific polymerization solvent, the oligomers generated during the polymerization reaction can be left in the ethylene polymer, and the resulting ethylene polymer has excellent processing performance.

[0025] Also, by using the slurry polymerization method of the ethylene polymer of the present invention, under other similar conditions of ethylene slurry homopolymerization (except that there is no comonomer involved in the polymerization reaction), the copolymerization method of ethylene and comonomer shows a more significant polymerization activity effect than the ethylene homopolymerization method, that is, the copolymerization activity is higher than the homopolymerization activity. Therefore, the comonomer molar insertion rate can be improved.

[0026] Therefore, the present invention can provide an ethylene-based polymer. Its bulk density and true density are high; its melt index, crystallinity, melting point, weight average molecular weight, etc. have a wide range and are adjustable and controllable; its molecular weight distribution has a medium range and is adjustable and controllable. The present invention is very suitable for customized preparation for producing ethylene polymers. Also, the resulting ethylene polymer has excellent processing performance.

[0027] The inventors have surprisingly found that in the ethylene slurry polymerization method, by using an alkane solvent having a boiling point of 5 to 55 °C or a mixed alkane solvent having a saturated vapor pressure of 20 to 150 KPa at 20 °C as the polymerization solvent, setting the ratio of hydrogen gas and ethylene within a specific range, and setting the ratio of hydrogen gas and comonomer within a specific range, the resulting ethylene polymer exhibits excellent processing performance when used in subsequent processing and applications.

[0028] Although not wishing to be bound by any theory, the inventors of the present invention believe that in the polymerization method of the present invention, the copolymerization reaction between ethylene and comonomer is the main reaction. However, by adjusting the ratio of hydrogen gas and ethylene within a specific range and adjusting the ratio of hydrogen gas and comonomer within a specific range, it is presumed that a specific copolymer type of oligomer can be generated during the polymerization reaction. In addition, in the specific polymerization solvent of the present invention, the solubility of the oligomer is very low, and the oligomer in the resulting ethylene polymer can be retained. This oligomer with a medium residue content is useful for improving the processing performance of the product, reducing the processing cost, and improving the processing and molding efficiency when used in subsequent processing of ethylene polymers (such as extrusion of pipes and profiles, film blowing, casting, mold blowing, roll molding, coating, wire drawing, pressing of sheets and profiles).

[0029] More specifically, the present invention provides a high-density ethylene polymer having an average particle size of 50 to 3000 μm, preferably 100 to 1000 μm. The high-density ethylene polymer of the present invention has a weight average molecular weight of 2×10 4 g / mol to 40×10 4 g / mol, preferably 5×10 4 g / mol to 30×10 4It is g / mol. The high-density ethylene polymer of the present invention has a molecular weight distribution of 1.8 to 10, preferably 2.0 to 8.0. The high-density ethylene polymer of the present invention has a comonomer molar insertion rate of 0.05 to 5 mol%, preferably 0.1 to 2.5 mol%. The high-density ethylene polymer of the present invention has a processing index in the film blowing test of 4.0 to 6.0, preferably 4.5 to 5.9, and more preferably 5.0 to 5.8.

[0030] In one embodiment of the present invention, the ethylene polymer has a melt index at a load of 2.16 Kg at 190 °C of 0.01 to 2500 g / 10 min, preferably 0.1 to 2000 g / 10 min, and more preferably 0.1 to 1000 g / 10 min. The high-density ethylene polymer of the present invention has a bulk density of 0.28 to 0.55 g / cm 3 , preferably 0.32 to 0.50 g / cm 3 It is. The high-density ethylene polymer of the present invention has a true density of 0.930 to 0.980 g / cm 3 , preferably 0.940 to 0.970 g / cm 3 , more preferably 0.942 to 0.970 g / cm 3 It is. The high-density ethylene polymer of the present invention has a crystallinity of 30 to 90%, preferably 40 to 80%. The high-density ethylene polymer of the present invention has a melting point of 105 to 147 °C, preferably 110 to 143 °C.

[0031] The present invention also provides a method for preparing an ethylene polymer. In this preparation method, the molar ratio of hydrogen gas to ethylene is 0.01 to 20:1, preferably 0.015 to 10:1; the molar ratio of hydrogen gas to comonomer is 0.1 to 30:1, preferably 0.15 to 25:1, more preferably 0.2 to 23:1. In the presence of a polyethylene catalyst system, a raw material containing ethylene, hydrogen gas and comonomer is subjected to tank-type slurry polymerization using an alkane solvent with a boiling point of 5 to 55 °C or a mixed alkane solvent with a saturated vapor pressure of 20 to 150 KPa at 20 °C as the polymerization solvent. The polyethylene catalyst system contains a polyethylene main catalyst selected from at least one of non-metallocene catalysts, metallocene catalysts, and Ziegler catalysts.

[0032] In one embodiment of the present invention, in the method for preparing an ethylene polymer, the ratio of the polyethylene main catalyst to the polymerization solvent is 0.001 to 0.500 mmol of polyethylene main catalyst / L of polymerization solvent, preferably 0.005 to 0.200 mmol of polyethylene main catalyst / L of polymerization solvent, more preferably 0.005 to 0.05 mmol of polyethylene main catalyst / L of polymerization solvent.

[0033] In the method for preparing an ethylene polymer of the present invention, the tank-type slurry polymerization of ethylene is carried out batchwise or continuously under the conditions that the polymerization temperature is 30 to 110 °C, preferably 50 to 100 °C; the polymerization pressure is 0.2 to 4.0 MPa, preferably 1.0 to 3.8 MPa; the molar ratio of hydrogen gas to ethylene is 0.01 to 20:1, preferably 0.015 to 10:1, and the molar ratio of hydrogen gas to comonomer is 0.1 to 30:1, preferably 0.15 to 25:1; and the slurry concentration is 50 to 500 g of polymer / L of polymerization solvent, preferably 100 to 400 g of polymer / L of polymerization solvent to produce an ethylene polymer.

[0034] In the method for preparing an ethylene polymer of the present invention, the solvent content in the powder material obtained after flash evaporation, filtration or centrifugation of the slurry after the polymerization reaction is completed is less than 20% by weight.

[0035] Hereinafter, the method for preparing the ethylene polymer of the present invention will be specifically described.

[0036] Specifically, the description of the polymerization solvent is as follows.

[0037] According to the present invention, examples of the alkane solvent having a boiling point of 5 to 55 ° C include 2,2-dimethylpropane (also known as neopentane, having a boiling point of 9.5 ° C and a saturated vapor pressure of 146.63 KPa at 20 ° C), 2-methylbutane (also known as isopentane, having a boiling point of 27.83 ° C and a saturated vapor pressure of 76.7 KPa at 20 ° C), n-pentane (having a boiling point of 36.1 ° C and a saturated vapor pressure of 56.5 KPa at 20 ° C), cyclopentane (having a boiling point of 49.26 ° C and a saturated vapor pressure of 34.6 KPa at 20 ° C), and preferably, an alkane solvent having a boiling point of 25 to 50 ° C can be mentioned.

[0038] The mixed alkane having a saturated vapor pressure of 20 to 150 KPa at 20 ° C, preferably the mixed alkane having a saturated vapor pressure of 40 to 110 KPa at 20 ° C, is a mixed solvent formed by mixing different alkane solvents in a certain ratio. For example, there are mixed solvents formed from hexane and its isomers, as well as pentane and isomer solvents, or alkane mixtures obtained by cutting according to the distillation range from a solvent distillation unit. Preferably, it is a mixed solvent of pentane and its isomers. Specifically, combinations such as n-pentane and isopentane, isopentane and neopentane, n-pentane and cyclopentane, n-pentane and neopentane, isopentane and cyclopentane, neopentane and cyclopentane, n-hexane and cyclopentane, n-hexane and n-pentane, n-pentane-isopentane-cyclopentane combination, n-pentane-n-hexane-isopentane combination, etc. can be mentioned. However, as long as it is a mixed alkane having a saturated vapor pressure of 20 to 150 KPa (preferably 40 to 110 KPa) at 20 ° C, it is not limited to these.

[0039] In one embodiment of the present invention, the mixed alkane having a saturated vapor pressure at 20 ° C of 20 to 150 KPa (preferably 40 to 110 KPa) is preferably formed by mixing two or more alkanes selected from n-pentane, isopentane, neopentane, and cyclopentane. The mixed alkane has a saturated vapor pressure at 20 ° C of 20 to 150 KPa (preferably 40 to 110 KPa), and more preferably, a combination of n-pentane and isopentane, a combination of isopentane and neopentane, a combination of n-pentane and cyclopentane, a combination of isopentane and cyclopentane, a combination of neopentane and cyclopentane, a combination of n-pentane-isopentane-cyclopentane, a combination of neopentane-isopentane-n-pentane, and the like. Regarding the ratio of each alkane in the mixed alkane, for example, when mixing two alkane solvents, their molar ratio can be 0.01 to 100:1, preferably 0.1 to 10:1. When mixing three alkane solvents, their molar ratio can be 0.01 to 100:0.01 to 100:1, preferably 0.1 to 10:0.1 to 10:1, provided that the saturated vapor pressure at 20 ° C of the resulting mixed alkane solvent is 20 to 150 KPa (preferably 40 to 110 KPa). In one embodiment of the present invention, only an alkane solvent having a boiling point of 5 to 55 ° C or a mixed alkane solvent having a saturated vapor pressure at 20 ° C of 20 to 150 KPa is used as the polymerization solvent.

[0040] The description of the polyethylene catalyst system is as follows.

[0041] In the present invention, the polyethylene catalyst system includes a polyethylene main catalyst selected from at least one of a non-metallocene catalyst, a metallocene catalyst, and a Ziegler-type catalyst.

[0042] In one embodiment of the present invention, the polyethylene catalyst system of the present invention can be a catalyst system including a polyethylene main catalyst and a cocatalyst.

[0043] As the polyethylene main catalyst, supported catalysts generally used in the art to catalyze ethylene polymerization can be used, for example, non-metallocene catalysts, metallocene catalysts, Ziegler-Natta catalysts, or complexes thereof. Specifically, supported single-site metal catalysts, supported multi-site metal catalysts, Ziegler-Natta type catalysts, supported composite catalysts of Ziegler-Natta and metallocene, supported bis or polyvalent metallocene catalysts, supported composite catalysts of Ziegler-Natta and non-metallocene, supported bis or polyvalent non-metallocene catalysts, supported composite catalysts of metallocene and non-metallocene, supported organic chromium-based catalysts, supported inorganic chromium-based catalysts, mixed organic chromium / chromium oxide catalysts, supported post-transition metal catalysts, supported Ziegler-Natta type catalysts, etc., which have the function of catalyzing ethylene polymerization can be mentioned.

[0044] Specifically, the polyethylene main catalyst can be selected from supported non-metallocene catalysts, for example, supported non-metallocene catalysts involved in the invention patents listed below: CN200310106156.X, CN200310106157.4, CN200410066068.6, CN200510119401.X, CN200610107651.6, CN200710162677.5, CN200710162667.1, CN200710162672.2, CN200710162675.6, CN200710162676.0, CN200710162666.7, CN200910180100.6, CN200910180607.1, CN200910180601.4, CN200910180606.7, CN200910180602.9, CN200910180605.2, CN200910180603.3, CN200910180604.8, CN200910210988.3, CN200910210984.5, CN200910210989.8, CN200910210986.4, CN200910210985.X, CN200910210990.0, CN200910210987.9, CN200910210991.5, CN201010286008.0, CN201010286012.7, CN201010284870.8, CN201010285982.5, CN201010284856.8, CN201010285970.2, CN201010285956.2, CN201010285969.X, CN201010285958.1, CN201010285967.0, CN201010285994.8, CN201110259336.6, CN201110259219.X, CN201110259330.9, CN201110259327.7, CN201110259367.1, CN201110259289.5, CN201110259359.7, CN201110259282.3, CN201110259318.8, CN201110259258.X, CN201110259300.8, CN201110259254.1, CN001110259299.9, CN201110259245.2, CN201110259296.5, CN201110259338.5. CN201110259370.3, CN201110259339.X, CN201110259293.1, CN201110259356.3, CN201210063756.1, CN201210063777.3, CN201210063788.1, CN201210063818.9, CN201210063824.4, CN201210063843.7, CN201210063854.5, CN201210063876.1, CN201210063878.0, CN201210063891.6, CN201210063894.X, CN201210063907.3, CN201210063909.2, CN201210063935.5, CN201210063941.0, CN201210063945.9, CN201310189677.X, CN201310227368.7, CN201310227370.4, CN201310227830.3, CN201310227393.5, CN201310452714.1, CN201710814678.7, CN201710814595.8, CN201710814594.3, CN201710814593.9, CN201710814592.4, CN201710814591.X, CN201811144599.0, CN201811144768.0, CN201811139936.7, CN201811140811.6, CN201811139946.0, CN201811139741.2, and CN201310091208.4.

[0045] According to the present invention, the term "non-metallocene complex" refers to a single-site olefin polymerization catalyst, in contrast to a metallocene catalyst, and the single-site olefin polymerization catalyst does not contain a cyclopentadienyl group or its derivatives (such as a cyclopentadiene ring, a fluorene ring, an indene ring, etc.) in its structure, and is a metal-organic compound that can exhibit olefin polymerization catalytic activity when combined with a co-catalyst (such as those described below). (Therefore, a non-metallocene complex may sometimes be referred to as a non-metallocene olefin polymerization-like complex). The compound contains a central metal atom and at least one polydentate ligand (preferably a tridentate ligand or a polydentate (higher than tridentate) ligand) bonded by a coordination bond to the central metal atom, and the term "non-metallocene ligand" refers to the above-mentioned polydentate ligand.

[0046] According to the present invention, the non-metallocene complex is selected from compounds having the following chemical structural formulas:

[0047]

Chemical formula

[0048] According to this chemical structural formula, the ligands that form a coordination bond with the central metal atom M include n groups X and m polydentate ligands (structural formulas in parentheses). According to the chemical structural formula of the polydentate ligand, the groups A, D, and E (coordination groups) form a coordination bond with the central metal atom M through the coordination atoms (heteroatoms such as N, O, S, Se, and P) contained in these groups.

[0049] According to the present invention, the absolute value of the total negative charge borne by all ligands (including group X and polydentate ligands) is the same as the absolute value of the positive charge borne by the central metal atom M.

[0050] In a more specific embodiment, the non-metallocene complex is selected from compounds (A) and (B) having the following chemical structural formulas.

[0051]

Chemical formula

[0052] In a more specific embodiment, the non-metallocene complex is selected from compounds (A-1) to (A-4) and compounds (B-1) to (B-4) having the following chemical structural formulas.

[0053]

Chemical formula

[0054] In all of the above chemical structural formulas, q is 0 or 1; d is 0 or 1; m is 1, 2 or 3; M is a central metal atom selected from metal atoms of Group III to Group XI of the periodic table, preferably a metal atom of Group IV. For example, Ti(IV), Zr(IV), Hf(IV), Cr(III), Fe(III), Ni(II), Pd(II) or Co(II) can be mentioned. n is 1, 2, 3 or 4 according to the valence state of the central metal atom M; X is a halogen atom, a hydrogen atom, a C 1 ~C 30 hydrocarbon group, a substituted C 1 ~C 30 hydrocarbon group, an oxygen-containing group, a nitrogen-containing group, a sulfur-containing group, a boron-containing group, an aluminum-containing group, a phosphorus-containing group, a silicon-containing group, a germanium-containing group or a tin-containing group, and a plurality of Xs may be the same or different and may be bonded to each other or form a ring; A is an oxygen atom, a sulfur atom, a selenium atom,

[0055]

Chemical formula

[0056] -NR 23 R 24 、-N(O)R 25 R 26 、

[0057]

Chemical formula

[0058] -PR 28 R 29 ,-P(O)R 30 OR 31 ,sulfonyl, sulfinyl or -Se(O)R 39 selected from, where N, O, S, Se, and P are each a coordinating atom; B is a nitrogen atom, a nitrogen-containing group, a phosphorus-containing group, or a C 1 ~C 30 hydrocarbon group selected; D is a nitrogen atom, an oxygen atom, a sulfur atom, a selenium atom, a phosphorus atom, a nitrogen-containing group, a phosphorus-containing group, a C 1 ~C 30 hydrocarbon group, sulfonyl, or sulfinyl selected, where N, O, S, Se, and P are each a coordinating atom; E is selected from a nitrogen-containing group, an oxygen-containing group, a sulfur-containing group, a selenium-containing group, a phosphorus-containing group, or cyano (-CN), where N, O, S, Se, and P are each a coordinating atom; F is selected from a nitrogen atom, a nitrogen-containing group, an oxygen atom, a sulfur atom, a selenium atom, a phosphorus atom, or a phosphorus-containing group, where N, O, S, Se, and P are each a coordinating atom; G is a C 1 ~C 30 hydrocarbon group, a substituted C 1 ~C 30 hydrocarbon group or an inert functional group selected; Y is selected from an oxygen atom, a nitrogen-containing group, an oxygen-containing group, a sulfur-containing group, a selenium-containing group or a phosphorus-containing group; where N, O, S, Se, and P are each a coordinating atom; Z is selected from a nitrogen-containing group, an oxygen-containing group, a sulfur-containing group, a selenium-containing group, a phosphorus-containing group, or cyano (-CN), for example, -NR 23 R 24 ,-N(O)R 25 R 26 ,-PR 28 R 29 ,-P(O)R 30 R 31 ,-OR 34 ,-SR 35 ,-S(O)R 36 ,-SeR 38 or -Se(O)R 39can be cited, where N, O, S, Se, and P are each a coordinating atom;

[0059] [Chemical formula]

[0060] represents a single bond or a double bond;

[0061] [Chemical formula]

[0062] represents a covalent bond or an ionic bond;

[0063] [Chemical formula]

[0064] represents a coordination bond, a covalent bond, or an ionic bond.

[0065] R 1 ~R 4 and R 6 ~R 21 are each independently selected from hydrogen, C 1 ~C 30 hydrocarbon group, substituted C 1 ~C 30 hydrocarbon group (preferably a halo-hydrocarbon group, such as -CH 2 Cl and -CH 2 CH 2 Cl) or an inert functional group. R 22 ~R 36 、R 38 and R 39 are each independently selected from hydrogen, C 1 ~C 30 hydrocarbon group or substituted C 1 ~C 30 hydrocarbon group (preferably a halo-hydrocarbon group, such as, -CH 2 Cl and -CH 2 CH 2is selected from (Cl). The above groups may be the same as or different from each other. Here, adjacent groups (e.g., R 1 and R 2 ), R 6 and R 7 ), R 7 and R 8 ), R 8 and R 9 ), R 13 and R 14 ), R 14 and R 15 ), R 15 and R 16 ), R 18 and R 19 ), R 19 and R 20 ), R 20 and R 21 ), R 23 and R 24 ), R 25 and R 26 etc.) may combine with each other to form a bond or form a ring. Preferably, an aromatic ring, for example, an unsubstituted benzene ring, or a benzene ring substituted with 1 to 4 substituents (C 1 ~C 30 hydrocarbon group, or substituted C 1 ~C 30 hydrocarbon group (preferably, a halohydrocarbon group, for example, -CH 2 Cl and -CH 2 CH 2 Cl) is selected). R 5 is selected from a lone pair of nitrogen, a hydrogen atom, C 1 ~C 30 hydrocarbon group, substituted C 1 ~C 30 hydrocarbon group, an oxygen-containing group, a sulfur-containing group, a nitrogen-containing group, a selenium-containing group or a phosphorus-containing group. When R 5 is an oxygen-containing group, a sulfur-containing group, a nitrogen-containing group, a selenium-containing group or a phosphorus-containing group, N, O, S, P, and Se in R 5 can act as coordinating atoms (coordinating with the central metal atom M).

[0066] In the context of the present invention, the above R 22 ~R 36 , R38 and R 39 each independently represents hydrogen, C 1 ~C 30 hydrocarbon group or substituted C 1 ~C 30 hydrocarbon group, and the above-mentioned groups may be the same as or different from each other, and adjacent groups may combine with each other to form a bond or a ring, preferably an aromatic ring.

[0067] In the context of the present invention, the inert functional groups that can be exemplified include halogen, oxygen-containing groups, nitrogen-containing groups, silicon-containing groups, germanium-containing groups, sulfur-containing groups, tin-containing groups, C 1 ~C 10 ester group, nitro (-NO 2 ) etc. (usually, C 1 ~C 30 hydrocarbon group and substituted C 1 ~C 30 hydrocarbon group excluded) and are selected from at least one of them.

[0068] In the context of the present invention, due to the limitation by the chemical structure of the polydentate ligand, the inert functional group has the following characteristics: (1) it does not interfere with the coordination process between the group A, group D, group E, group F, group Y, or group Z and the central metal atom M, and (2) the central metal atom M has a lower coordination ability than the group A, group D, group E, group F, group Y, and group Z, and does not replace the existing coordination between these groups and the central metal atom M.

[0069] According to the present invention, in all the above chemical structural formulas, depending on the specific situation, R 21 and the group Z, or R 13 and the group Y, etc., any two or more adjacent groups can combine with each other to form a ring, preferably a C 6 ~C 30 aromatic heterocyclic ring (for example, pyridine ring, etc.) containing a heteroatom from the group Z or group Y can be formed, where the aromatic heterocyclic ring is C 1 ~C 30 hydrocarbon group and substituted C 1~C 30 Optionally substituted by one or more substituents selected from hydrocarbon groups.

[0070] In the context of the present invention, the halogen is selected from F, Cl, Br or I. The nitrogen-containing group is

[0071]

Chemical formula

[0072] -NR 23 R 24 、-T-NR 23 R 24 Or -N(O)R 25 R 26 Selected from. The phosphorus-containing group is

[0073]

Chemical formula

[0074] -PR 28 R 29 、-P(O)R 30 R 31 Or -P(O)R 32 (OR 33 ) Selected from. The oxygen-containing group is hydroxy, -OR 34 And -T-OR 34 Selected from. The sulfur-containing group is -SR 35 、-T-SR 35 、-S(O)R 36 Or -T-SO 2 R 37 Selected from. The selenium-containing group is -SeR 38 、-T-SeR 38 、-Se(O)R 39 Or -T-Se(O)R 39 Selected from. The group T is C 1 ~C 30 Hydrocarbon group or substituted C 1 ~C 30 Selected from hydrocarbon groups. The R37 is selected from hydrogen, C 1 ~C 30 hydrocarbon group or substituted C 1 ~C 30 hydrocarbon group.

[0075] In the context of the present invention, the C 1 ~C 30 hydrocarbon group is C 1 ~C 30 alkyl (preferably C 1 ~C 6 alkyl, such as isobutyl), C 7 ~C 50 alkylaryl (such as tolyl, dimethylphenyl, diisobutylphenyl, etc.), C 7 ~C 50 arylalkyl (such as benzyl), C 3 ~C 30 cyclic alkyl group, C 2 ~C 30 alkenyl, C 2 ~C 30 alkynyl, C 6 ~C 30 aryl (such as phenyl, naphthyl, anthracyl, etc.), C 8 ~C 30 fused ring group or C 4 ~C 30 heterocyclic group selected from, wherein the heterocyclic group contains 1 to 3 heteroatoms selected from nitrogen atom, oxygen atom or sulfur atom, such as pyridyl, pyrrolyl, furyl, thienyl, etc.

[0076] According to the present invention, in the context of the present invention, the C 1 ~C 30 hydrocarbon group may refer to C 1 ~C 30 hydrocarbodiyl (a divalent group, or also called C 1 ~C 30 hydrocarbylene group) or C 1 ~C 30 hydrocarbon triyl (a trivalent group), which is obvious to those skilled in the art.

[0077] In the context of the present invention, the substituted C 1 ~C 30 hydrocarbon group refers to a C 1 ~C 30 hydrocarbon group having one or more inert substituents. The so-called inert substituent refers to a substituent that does not substantially interfere with the coordination process between the aforementioned ligand (referring to group A, group D, group E, group F, group Y, and group Z, or optionally including an R 5 group) and the central metal atom M; in other words, due to the limitations imposed by the chemical structure of the multidentate ligand described in the present application, these substituents cannot or do not occur (e.g., affected by steric hindrance) to form a coordination bond by coordinating with the central metal atom M. Generally speaking, the inert substituent is selected from halogen or C 1 ~C 30 alkyl (preferably C 1 ~C 6 alkyl such as isobutyl).

[0078] In the context of the present invention, the boron-containing group is selected from BF 4 - , (C 6 F 5 ) 4 B - or (R 40 BAr 3 ) - ; the aluminum-containing group is selected from alkylaluminum, AlPh 4 - , AlF 4 - , AlCl 4 - , AlBr 4 - , AlI 4 - or R 41 AlAr 3 - ; the silicon-containing group is selected from -SiR 42 R 43 R 44 or -T-SiR 45 ; the germanium-containing group is -GeR 46 R47 R 48 or -T-GeR 49 selected from; said tin-containing group is -SnR 50 R 51 R 52 , -T-SnR 53 or -T-Sn(O)R 54 selected from, where Ar represents C 6 ~C 30 aryl. R 40 ~R 54 are each independently hydrogen, the above-mentioned C 1 ~C 30 hydrocarbon group, or the above-mentioned substituted C 1 ~C 30 hydrocarbon group selected from. The above-mentioned groups may be the same as or different from each other, and adjacent groups may be bonded to each other to form a bond or a ring, where the group T is defined as above.

[0079] Examples of non-metallocene complexes include, for example, the following compounds.

[0080]

Chemical formula

[0081] The non-metallocene complex is preferably selected from the following compounds.

[0082]

Chemical formula

[0083] The non-metallocene complex is more preferably selected from the following compounds:

[0084]

Chemical formula

[0085] The non-metallocene complex is more preferably selected from the following compounds.

[0086] [Chemical formula]

[0087] These non-metallocene complexes can be used alone or in combination at any ratio.

[0088] According to the present invention, the multidentate ligand in the non-metallocene complex is not a diethyl compound that has been conventionally used as an electron donor compound in the art.

[0089] The non-metallocene complex or the multidentate ligand can be prepared according to any method known to those skilled in the art. For specific details of the preparation method, reference may be made to, for example, WO03 / 010207, as well as Chinese Patents ZL01126323.7 and ZL02110844.7, etc. (the entire contents of which are incorporated herein by reference).

[0090] Among them, the supported non-metallocene catalyst is preferred, and the supported single-component non-metallocene catalyst is more preferred.

[0091] As the polyethylene main catalyst, as long as it is a catalyst containing a metallocene catalyst, it can be selected from supported metallocene catalysts. It can be a single-component metallocene catalyst or a composite catalyst of a metallocene catalyst and at least one other catalyst. Specifically, examples include a composite catalyst of a supported Ziegler-Natta and a metallocene, a supported bis or polyvalent metallocene catalyst, etc.

[0092] Specifically, the polyethylene main catalyst is a supported metallocene catalyst, for example, CN201110247347.2, CN201110080343.X, CN201010518904.5, CN201010519660.2, CN201210289014.0, CN200910078596.6, CN201310090758.4, CN201310090736.8, 201310521768.9, CN201410589467.4, CN201410590067.5, CN201610835700.1, 201610944191.6, CN201710959423.X, CN201110247349.1, CN201110080294.X, CN201110080395.7, CN201210289017.4, CN201210289031.4, CN201310091192.7, CN201310540973.X, CN201510724626.1, CN200410086283.2, CN200610137777.8, CN201610944182.7, CN201710312720.5, CN201110080422.0, CN201110080422.0, CN201110080394.2, CN201010519406.2, CN201010519715.X, CN201010519174.0, CN201010519429.3, CN201210289004.7, CN201310090847.9, CN201310091209.9, CN201310540975.9, CN201410554709.6, CN201410513506.2, CN00130388.0, CN200710176589.0, CN201610944083.9, CN201110246705.8, CN201110247085.X, CN2011102914899, CN201010521674.8, CN201310090752.7, CN201310090848.3, CN2013100908483, CN201510624502.6, CN201710166709.2, CN20171031225.2, CN201110246710.9, CN201110080374.5, CN201010519797.8, CN201210289012.1, CN201210418645.It can be selected from supported metallocene catalysts involved in invention patents such as CN201310090998.4, CN201410252254.2, CN201610393399.3, CN201610956141.X, CN201710958837.0, supported metallocene catalysts of types 101 and 201 of Grace Davison, and XCAT type metallocene catalysts of Univation.

[0093] Among them, supported metallocene catalysts are preferred, and supported single-component metallocene catalysts are more preferred.

[0094] Among them, the structures of the metallocene ligand and the metallocene complex in the metallocene catalyst can be selected from a uniform dicyclopentadiene structure, a mixed dicyclopentadiene structure, a chiral metallocene structure, a single / double / multiple cross-linked structure, a monocyclopentadiene structure, a monocyclopentadiene or dicyclopentadiene structure with a limited geometric configuration, a cross-linked mixed cyclopentadiene structure, a cationic structure, etc.

[0095] The polyethylene main catalyst can be selected from supported Ziegler-Natta type catalysts. As long as it is a catalyst containing a Ziegler-Natta type catalyst, it can be a single-component Ziegler-Natta type catalyst or a composite catalyst of a Ziegler-Natta type catalyst and at least one other catalyst. Specifically, examples include Ziegler-Natta type catalysts, supported composite catalysts of Ziegler-Natta and metallocene, supported composite catalysts of Ziegler-Natta and non-metallocene, supported Ziegler-Natta type catalysts, etc.

[0096] More specifically, the polyethylene main catalyst can be selected from supported Ziegler-Natta catalysts involved in invention patents such as CN201010522112.5, CN201010240355.X, CN201010502803.9, CN201010511310.1, CN200710121105.2, CN201010502778.4, CN201010502717.8, CN201010240379.5, CN201110148492.5, CN201110148493.X, CN201110148527.5, CN201110148545.3, CN201110306102.2, CN201010240378.0, CN200410086382.0, CN98101108.X, CN200410078280.4, CN200910088546.6, etc., such as existing catalysts of the BCH series, BCE series, BCG series and BCS series of Beijing Auda Division of Sinopec Catalyst Co., Ltd.; SCG series catalysts of Shanghai Leader Catalyst Co., Ltd.; TH series catalysts of Zibo Xinsu Chemical Co., Ltd.; M and J type catalysts of Univation Corporation; XY-H and XY-S type catalysts of Liaoning Yingkou, etc.

[0097] Among them, supported Ziegler-Natta catalysts are preferred, and supported single-component Ziegler-Natta catalysts are more preferred. For example, catalysts of the BCH series, BCE series, BCG series and BCS series of Beijing Auda Division of Sinopec Catalyst Co., Ltd., SCG series catalysts of Shanghai Leader Catalyst Co., Ltd., TH series catalysts of Zibo Xinsu Chemical Co., Ltd., XY-H type catalysts of Yingkou Xiangyang Catalyst Co., Ltd., etc. are commercially available.

[0098] The active metal in the polyethylene main catalyst can be an active metal commonly used in the art, for example, Group IVB elements such as titanium, zirconium or hafnium; Group VB elements such as vanadium, Group VIII elements such as iron, cobalt, nickel and palladium, and can be selected preferably from Group IVB metal elements, and most preferably from titanium metal elements.

[0099] Among them, supported non-metallocene catalysts, supported metallocene catalysts, and Ziegler-Natta type catalysts are preferred.

[0100] Examples of the polyethylene main catalyst include, but are not limited to, non-metallocene catalysts, metallocene catalysts, and Ziegler-Natta type catalysts (typically coordinated with an active metal); the active metal can be an active metal commonly used in the art, for example, Group IVB elements such as titanium, zirconium or hafnium; Group VB elements such as vanadium, Group VIIB elements such as chromium; Group VIII elements such as iron, cobalt, nickel, and palladium, and can be selected preferably from Group IVB metal elements, and most preferably from titanium metal elements.

[0101] According to the present invention, the polyethylene main catalyst can be a supported catalyst, and the carrier can be selected from a porous silica gel carrier, a layered porous carrier, an organic polymer carrier, a magnesium compound carrier, an oxide carrier, etc.

[0102] Among them, the magnesium compound carrier can be selected from magnesium compounds, for example. For example, magnesium halide, alkoxymagnesium halide, alkoxymagnesium, alkylmagnesium, alkylmagnesium halide and alkylalkoxymagnesium can be mentioned.

[0103] Specifically, examples of the magnesium halide include magnesium chloride (MgCl 2 ), magnesium bromide (MgBr 2) Magnesium iodide (MgI 2 ) Magnesium fluoride (MgF 2 ) can be mentioned, and preferably it is magnesium chloride.

[0104] Examples of alkoxymagnesium halides include, for example, methyloxymagnesium chloride (Mg(OCH 3 )Cl), ethyloxymagnesium chloride (Mg(OC 2 H 5 )Cl), propyloxymagnesium chloride (Mg(OC 3 H 7 )Cl), n-butyloxymagnesium chloride (Mg(OC 4 H 9 )Cl), isobutyloxymagnesium chloride (Mg(i-OC 4 H 9 )Cl), methyloxymagnesium bromide (Mg(OCH 3 )Br), ethyloxymagnesium bromide (Mg(OC 2 H 5 )Br), propyloxymagnesium bromide (Mg(OC 3 H 7 )Br), n-butyloxymagnesium bromide (Mg(OC 4 H 9 )Br), isobutyloxymagnesium bromide (Mg(i-OC 4 H 9 )Br), methyloxymagnesium iodide (Mg(OCH 3 )I), ethyloxymagnesium iodide (Mg(OC 2 H 5 )I), propyloxymagnesium iodide (Mg(OC 3 H 7 )I), n-butyloxymagnesium iodide (Mg(OC 4 H 9 )I), isobutyloxymagnesium iodide (Mg(i-OC 4 H 9)Examples thereof include methylmagnesium chloride, ethylmagnesium chloride, and isobutylmagnesium chloride, with methylmagnesium chloride, ethylmagnesium chloride, and isobutylmagnesium chloride being preferred.

[0105] Examples of alkoxymagnesium include, for example, methylmagnesium (Mg(OCH 3 ) 2 ), ethylmagnesium (Mg(OC 2 H 5 ) 2 ), propylmagnesium (Mg(OC 3 H 7 ) 2 ), butylmagnesium (Mg(OC 4 H 9 ) 2 ), isobutylmagnesium (Mg(i-OC 4 H 9 ) 2 ), 2-ethylhexylmagnesium (Mg(OCH 2 CH(C 2 H 5 )C 4 H 8 ) 2 ), etc. Among them, ethylmagnesium and isobutylmagnesium are preferred.

[0106] Examples of alkylmagnesium include, for example, methylmagnesium (Mg(CH 3 ) 2 ), ethylmagnesium (Mg(C 2 H 5 ) 2 ), propylmagnesium (Mg(C 3 H 7 ) 2 ), n-butylmagnesium (Mg(C 4 H 9 ) 2 ), isobutylmagnesium (Mg(i-C 4 H 9 ) 2 ), etc. Among them, ethylmagnesium and n-butylmagnesium are preferred.

[0107] Examples of alkylmagnesium halides include methylmagnesium chloride (Mg(CH 3 )Cl), ethylmagnesium chloride (Mg(C 2 H 5 )Cl), propylmagnesium chloride (Mg(C 3 H 7 )Cl), n-butylmagnesium chloride (Mg(C 4 H 9 )Cl), isobutylmagnesium chloride (Mg(i-C 4 H 9 )Cl), methylmagnesium bromide (Mg(CH 3 )Br), ethylmagnesium bromide (Mg(C 2 H 5 )Br), propylmagnesium bromide (Mg(C 3 H 7 )Br), n-butylmagnesium bromide (Mg(C 4 H 9 )Br), isobutylmagnesium magnesium bromide (Mg(i-C 4 H 9 )Br), methylmagnesium iodide (Mg(CH 3 )I), ethylmagnesium iodide (Mg(C 2 H 5 )I), propylmagnesium iodide (Mg(C 3 H 7 )I), n-butylmagnesium iodide (Mg(C 4 H 9 )I), and isobutylmagnesium iodide (Mg(i-C 4 H 9 )I), etc. Methylmagnesium chloride, ethylmagnesium chloride, and isobutylmagnesium chloride are preferred.

[0108] Examples of alkylalkoxymagnesium include methylmethoxymagnesium (Mg(OCH 3 )(CH 3 )) and methylethoxymagnesium (Mg(OC 2 H 5 )(CH3 )) Methylpropylmagnesium (Mg(OC 3 H 7 )(CH 3 )) Methyl n - butylmagnesium (Mg(OC 4 H 9 )(CH 3 )) Methyl isobutylmagnesium (Mg(i - OC 4 H 9 ))(CH 3 )) Ethylmethylmagnesium (Mg(OCH 3 )(C 2 H 5 )) Ethylethylmagnesium (Mg(OC 2 H 5 )(C 2 H 5 )) Ethylpropylmagnesium (Mg(OC 3 H 7 )(C 2 H 5 )) Ethyl n - butylmagnesium (Mg(OC 4 H 9 )(C 2 H 5 )) Ethyl isobutylmagnesium (Mg(i - OC 4 H 9 ))(C 2 H 5 )) Propylmethylmagnesium (Mg(OCH 3 )(C 3 H 7 )) Propylethylmagnesium (Mg(OC 2 H 5 )(C 3 H 7 )) Propylpropylmagnesium (Mg(OC 3 H 7 )(C 3 H 7 )) Propyl n - butylmagnesium (Mg(OC 4 H 9 )(C 3 H 7 )) Propyl isobutylmagnesium (Mg(i - OC 4 H 9 )(C3 H 7 )), n-butylmethyloxymagnesium (Mg(OCH 3 )(C 4 H 9 )), n-butylethyloxymagnesium (Mg(OC 2 H 5 )(C 4 H 9 )), n-butylpropyloxymagnesium (Mg(OC 3 H 7 )(C 4 H 9 )), n-butyln-butyloxymagnesium (Mg(OC 4 H 9 )(OC 4 H 9 )), n-butylisobutyloxymagnesium (Mg(i-OC 4 H 9 )(C 4 H 9 )), isobutylmethyloxymagnesium (Mg(OCH 3 )(i-C 4 H 9 )), isobutylethyloxymagnesium (Mg(OC 2 H 5 )(i-C 4 H 9 )), isobutylpropyloxymagnesium (Mg(OC 3 H 7 )(i-C 4 H 9 )), isobutyln-butyloxymagnesium (Mg(OC 4 H 9 )(i-C 4 H 9 )), isobutylisobutyloxymagnesium (Mg(i-OC 4 H 9 )(i-C 4 H 9 )) and the like can be mentioned, and butylethyloxymagnesium is preferred.

[0109] These magnesium compounds may be used alone or in combination.

[0110] Examples of the porous carrier include organic porous solids or inorganic porous solids that have been conventionally used as carriers in the preparation of olefin polymerization catalysts supported in the relevant technical field.

[0111] Specifically, examples of the organic porous solid include olefin homopolymers or copolymers, polyvinyl alcohol or its copolymers, cyclodextrin, (co)polyesters, (co)polyamides, vinyl chloride homopolymers or copolymers, acrylate homopolymers or copolymers, methacrylate homopolymers or copolymers, styrene homopolymers or copolymers, etc. Partially crosslinked forms of these homopolymers or copolymers can be mentioned. Here, a partially crosslinked styrene polymer (for example, having a crosslinking degree of at least 2% but less than 100%) is preferred.

[0112] According to the present invention, when an organic porous solid is used as the carrier, the organic porous solid can also be thermally activated before use. The thermal activation treatment can be carried out by a usual method, for example, by heating the organic porous solid under reduced pressure or in an inert atmosphere. The inert atmosphere in this specification means that the gas contains very little or no component that can react with the organic porous solid. Examples of the inert atmosphere include a nitrogen gas atmosphere or a noble gas atmosphere, and a nitrogen gas atmosphere is preferred. Since the organic porous solid has poor heat resistance, the thermal activation treatment should be carried out on the premise that it does not damage the structure and basic composition of the organic porous solid itself. Generally, the thermal activation temperature is 50 to 400 ° C, preferably 100 to 250 ° C, and the thermal activation time is 1 to 24 hours, preferably 2 to 12 hours. After the thermal activation treatment, the organic porous solid needs to be kept under positive pressure in an inert atmosphere for later use.

[0113] Examples of the inorganic porous solid include refractory oxides of Group IIA, IIIA, IVA, or IVB metals in the periodic table of elements (e.g., silica (also known as silicon oxide or silica gel), alumina, magnesia, titania, zirconia, thoria, etc.), or any refractory composite oxides of these metals (e.g., silica-alumina, magnesia-alumina, titania-silica, titania-magnesia, and titania-alumina, etc.), and clay, molecular sieves (e.g., ZSM-5 and MCM-41), mica, montmorillonite, bentonite, diatomaceous earth, etc. The inorganic porous solid may also include oxides formed by thermal hydrolysis of gaseous metal halides or gaseous silicon compounds, such as silica gel obtained by thermal hydrolysis of silicon tetrachloride, alumina obtained by thermal hydrolysis of aluminum trichloride, etc. Silica, alumina, magnesia, silica-alumina, magnesia-alumina, titania-silica, titania, molecular sieve, montmorillonite, etc. are preferred, and silica is particularly preferred. Suitable silica can be prepared by conventional methods or any commercially available products, such as Grace955, Grace948, Grace SP9-351, Grace SP9-485, Grace SP9-10046, Davsion Syloid245, and Aerosil812 of Grace Corporation, ES70, ES70X, ES70Y, ES70W, ES757, EP10X, and EP11 of Ineos Corporation, and CS-2133 and MS-3040 of PQ Corporation.

[0114] Specifically, the description of the usage amount of the polyethylene main catalyst is as follows.

[0115] According to the present invention, the usage amount of the polyethylene main catalyst can be the usage amount of the catalyst generally adopted in the art. The usage principle is to determine its main usage amount according to the ethylene slurry polymerization activity of the catalyst, that is, under a higher ethylene slurry polymerization activity, a lower usage amount of the polyethylene main catalyst is used, and under a lower ethylene slurry polymerization activity, a higher usage amount of the polyethylene main catalyst is used, so as to achieve that the concentration of the slurry meets the requirements of the present invention. For example, based on the active metal element in the polyethylene main catalyst, the ratio of the polyethylene main catalyst to the polymerization solvent is 0.001 - 0.500 mmol of the polyethylene main catalyst / L of the polymerization solvent, preferably 0.005 - 0.200 mmol of the polyethylene main catalyst / L of the polymerization solvent, more preferably 0.005 - 0.05 mmol of the polyethylene main catalyst / L of the polymerization solvent. Generally, when preparing polyethylene under a high polymerization activity (for example, a lower molar ratio of hydrogen gas to ethylene, a higher molar ratio of comonomer to ethylene), under a higher polymerization pressure, or at a higher polymerization temperature, a lower concentration of the polyethylene main catalyst can be used; in contrast, for example, under a higher molar ratio of hydrogen gas to ethylene, a lower molar ratio of comonomer to ethylene, a lower polymerization pressure, or a lower polymerization temperature, a higher concentration of the polyethylene main catalyst can be used. Also, the ratio of the polyethylene main catalyst to the polymerization solvent can be 0.005 - 0.05 mmol of the polyethylene main catalyst / L of the polymerization solvent.

[0116] In addition, in the present invention, unless otherwise specified, the molar amount of the polyethylene main catalyst is based on the active metal element in the polyethylene main catalyst.

[0117] Also, in the present invention, the description of the cocatalyst is as follows.

[0118] According to the present invention, the cocatalyst is selected from aluminoxane, alkylaluminum, haloalkylaluminum, fluoroborane, alkylborane or alkylammonium borate, or a mixture thereof.

[0119] Among them, as the aluminoxane as a cocatalyst, for example, the following general formula (I): (R)(R)Al-(Al(R)-O) n -O-Al(R)(R) linear aluminoxane represented by, and the following general formula (II): -(Al(R)-O-) n+2 - cyclic aluminoxane represented by can be mentioned:

[0120]

Chemical formula

[0121] In the above general formulas (I) and (II), the group R is the same as or different from each other (preferably the same), and each independently, C 1 ~C 8 alkyl, preferably selected from methyl, ethyl, propyl, butyl, and isobutyl, most preferably methyl and isobutyl; n is any integer in the range of 1 to 50, preferably any integer in the range of 10 to 30.

[0122] As the aluminoxane, methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, and n-butylaluminoxane are preferred, and methylaluminoxane and isobutylaluminoxane are more preferred.

[0123] These aluminoxanes may be used alone or in combination at any ratio.

[0124] As the alkylaluminum, for example, compounds represented by the following general formula can be mentioned: Al(R) 3 (In the formula, the group R is the same as or different from each other (preferably the same), and each independently, C 1 ~C 8 alkyl, preferably selected from methyl, ethyl, propyl, butyl and isobutyl, most preferably methyl, isobutyl).

[0125] Specifically, examples of the alkylaluminum include trimethylaluminum (Al(CH 3 ) 3 ), triethylaluminum (Al(CH 3 CH 2 ) 3 ), tri-n-propylaluminum (Al(C 3 H 7 ) 3 ), tri-isopropylaluminum (Al(i-C 3 H 7 ) 3 ), tri-isobutylaluminum (Al(i-C 4 H 9 ) 3 ), tri-n-butylaluminum (Al(C 4 H 9 ) 3 ), tri-isopentylaluminum (Al(i-C 5 H 11 ) 3 ), tri-n-pentylaluminum (Al(C 5 H 11 ) 3 ), tri-n-hexylaluminum (Al(C 6 H 13 ) 3 ), tri-isohexylaluminum (Al(i-C 6 H 13 ) 3 ), diethylmethylaluminum (Al(CH 3 )(CH 3 CH 2 ) 2 ), dimethylethylaluminum ((Al(CH 3 CH 2 )(CH 3 ) 2 ), etc. Trimethylaluminum, triethylaluminum, tripropylaluminum, and tri-isobutylaluminum are preferred, and triethylaluminum and tri-isobutylaluminum are most preferred.

[0126] These alkyl aluminums may be used alone or in combination at any ratio.

[0127] Examples of the haloalkyl aluminum include compounds represented by the following general formula: Al(R) n X 3-n (In the formula, the groups R are the same as or different from each other (preferably the same), each independently selected from C 1 ~C 8 alkyl, preferably methyl, ethyl, propyl, butyl and isobutyl, most preferably methyl and isobutyl; X represents F, Cl, Br or I; n represents 1 or 2).

[0128] Specifically, examples of the haloalkyl aluminum include monochlorodimethylaluminum (Al(CH 3 ) 2 Cl), dichlorodimethylaluminum (Al(CH 3 )Cl 2 ), monochlorodiethylaluminum (Al(CH 3 CH 2 ) 2 Cl), dichlorodiethylaluminum (Al(CH 3 CH 2 )Cl 2 ), monochlorodipropylaluminum (Al(C 3 H 7 ) 2 Cl), dichlorodipropylaluminum (Al(C 3 H 7 )Cl 2 ), monochlorodi-n-butylaluminum (Al(C 4 H 9 ) 2 Cl), dichlorodi-n-butylaluminum (Al(C 4 H 9 )Cl 2 ), monochlorodiisobutylaluminum (Al(i-C 4 H 9 ) 2(Cl), dichloro-isobutylaluminum (Al(i-C 4 H 9 )Cl 2 ), monochlorodi-n-pentylaluminum (Al(C 5 H 11 ) 2 Cl), dichloro-n-pentylaluminum (Al(C 5 H 11 )Cl 2 ), monochlorodiisopentylaluminum (Al(i-C 5 H 11 ) 2 Cl), dichloro-isopentylaluminum (Al(i-C 5 H 11 )Cl 2 ), monochlorodi-n-hexylaluminum (Al(C 6 H 13 ) 2 Cl), dichloro-n-hexylaluminum (Al(C 6 H 13 )Cl 2 ), monochlorodiisohexylaluminum (Al(i-C 6 H 13 ) 2 Cl), dichloro-isohexylaluminum (Al(i-C 6 H 13 )Cl 2 ), monochloromethylethylaluminum (Al(CH 3 )(CH 3 CH 2 )Cl), monochloromethylpropylaluminum (Al(CH 3 )(C 3 H 7 )Cl), monochloromethyl-n-butylaluminum (Al(CH 3 )(C 4 H 9 )Cl), monochloromethyl-isobutylaluminum (Al(CH 3 )(i-C 4 H 9 )Cl), monochloroethylpropylaluminum (Al(CH 2 CH 3 )(C 3 H 7Cl), monochloroethyl-n-butylaluminum (AlCH 2 CH 3 )(C 4 H 9 )Cl), monochloromethyl-isobutylaluminum (Al(CH 2 CH 3 )(i-C 4 H 9 )Cl), etc. can be mentioned. Preferably, they are dichloroethylaluminum, dichloroethylaluminum, monochlorodi-n-butylaluminum, dichloro-n-butylaluminum, monochlorodiisobutylaluminum, dichloro-isobutylaluminum, monochlorodi-n-hexylaluminum, dichloro-n-hexylaluminum, more preferably chlorodiethylaluminum, dichloroethylaluminum and monochlorodi-n-hexylaluminum, and most preferably monochlorodiethylaluminum.

[0129] These haloalkylaluminums may be used alone or in combination at any ratio.

[0130] As the fluoroborane, alkylborane, and alkylammonium borate, those generally used in the art can be directly used without special limitation. For example, trimethylborane, triethylborane, triphenylborane, tri(pentafluorophenyl)borane, tri[3,5-bis(trifluoromethyl)phenyl]borane, tris(pentafluorophenyl)borane, trityltetrakis(pentafluorophenyl)borate, N,N-dimethylbenzeneammonium tetrakis(pentafluorophenyl)borate, 1-butyl-3-methylimidazolium tetrafluoroborate, ferrocenium tetrafluoroborate, trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate, tri-propylammonium tetraphenylborate, tri-butylammonium tetraphenylborate, trimethylammonium tetra(p-tolyl)borate, tri-propylammonium tetra(p-tolyl)borate, trimethylammonium tetra(p, o-dimethylphenyl)borate, triethylammonium tetra(p, o-dimethylphenyl)borate, trimethylammonium tetra(p-trifluoromethylphenyl)borate, tri-butylammonium tetra(p-trifluoromethylphenyl)borate, tri-butylammonium tetrakis(pentafluorophenyl)borate, N,N-diethylbenzeneammonium tetraphenylborate, N,N-diethylbenzeneammonium tetrakis(pentafluorophenyl)borate, diethylammonium tetrakis(pentafluorophenyl)borate, etc. can be selected.

[0131] Also, according to the present invention, the cocatalyst may be used alone or in combination at any ratio as necessary. Furthermore, the ratio of each component in the mixture is not particularly limited and can be arbitrarily selected as necessary.

[0132] According to the present invention, the cocatalyst is generally used in solution form. When preparing a solution of the cocatalyst, there is no particular limitation on the solvent used at this time as long as the cocatalyst can be dissolved. Generally, alkane solvents such as n-pentane, isopentane, cyclopentane, and neopentane, or aromatic solvents such as toluene, ethylbenzene, and xylene can be selected. According to the present invention, in order to facilitate subsequent separation, it is preferable to use the same solvent as the polymerization solvent or the same solvent as one of the mixed solvents used in the polymerization.

[0133] Unless otherwise specified, in the present invention, when the cocatalyst is aluminoxane, alkylaluminum or haloalkylaluminum, the molar amount of the cocatalyst is based on the molar amount of the Al element; when the cocatalyst is fluoroborane, alkylborane or alkylammonium borate, it should be noted that the molar amount of the cocatalyst is based on the molar amount of the B element.

[0134] Specifically, the ratio and addition method of the cocatalyst and the polyethylene main catalyst will be described below.

[0135] According to the present invention, regarding the ratio of the cocatalyst to the polyethylene main catalyst, based on all aluminum elements in aluminoxane, alkylaluminum, and haloalkylaluminum in the cocatalyst, and based on the active metal element in the polyethylene main catalyst, the molar ratio of aluminum to the active metal is 10 to 500:1, preferably, the molar ratio of aluminum to the active metal is 20 to 100:1.

[0136] Based on the boron element in fluoroborane, alkylborane or alkylammonium borate in the cocatalyst, and based on the active metal element in the polyethylene main catalyst, the molar ratio of boron to the active metal is 1 to 50:1, preferably the molar ratio of boron to the active metal is 1 to 20:1.

[0137] Based on all aluminum elements in aluminoxane, alkylaluminum, or haloalkylaluminum in the cocatalyst, and boron elements in fluoroborane, alkylborane, or alkylammonium borate in the cocatalyst, and based on the active metal element in the polyethylene main catalyst, the molar ratio of aluminum:boron:active metal is 10 to 100:1 to 20:1, preferably the molar ratio of aluminum:boron:active metal is 20 to 50:1 to 10:1.

[0138] The manner of adding the polyethylene main catalyst and the cocatalyst to the polymerization reaction system is not particularly limited. For example, first add the polyethylene main catalyst and then add the cocatalyst; or first add the cocatalyst and then add the polyethylene main catalyst; or first contact and mix the polyethylene main catalyst and the cocatalyst and then add them together; or add the main catalyst and the cocatalyst separately but simultaneously; or first add a part of the cocatalyst and then add the polyethylene main catalyst and the remaining cocatalyst simultaneously; or first add a part of the polyethylene main catalyst and then add the remaining polyethylene main catalyst and the cocatalyst simultaneously. When adding the polyethylene main catalyst and the cocatalyst separately, they can be continuously added to the same charge pipe or to different charge pipes; on the other hand, when adding the polyethylene main catalyst and the cocatalyst separately but simultaneously, they should be added to different charge pipes.

[0139] Specifically, the description of the conditions for ethylene slurry polymerization in the preparation of ethylene polymers is as follows.

[0140] According to one embodiment of the present invention, the polymerization temperature of the slurry polymerization is 30 to 110 ° C, preferably 50 to 100 ° C. According to one embodiment of the present invention, the polymerization pressure is 0.2 to 4.0 MPa, preferably 1.0 to 3.8 MPa. According to one embodiment of the present invention, the molar ratio of hydrogen gas to ethylene is 0.01 to 20:1, preferably 0.015 to 10:1. According to one embodiment of the present invention, the molar ratio of hydrogen gas to comonomer is 0.1 to 30:1, preferably 0.15 to 25:1, more preferably 0.2 to 23:1. According to one embodiment of the present invention, the molar ratio of comonomer to ethylene is 0.01 to 0.500:1, preferably 0.015 to 0.350:1.

[0141] According to one embodiment of the present invention, the ratio of the polyethylene main catalyst based on the amount of the active metal to the polymerization solvent is 0.001 to 0.500 mmol of polyethylene main catalyst / L of polymerization solvent, preferably 0.005 to 0.200 mmol of polyethylene main catalyst / L of polymerization solvent, more preferably 0.005 to 0.05 mmol of polyethylene main catalyst / L of polymerization solvent. According to one embodiment of the present invention, the slurry concentration is 50 to 500 g of polymer / L of polymerization solvent, preferably 100 to 400 g of polymer / L of polymerization solvent.

[0142] Specifically, the description of the ethylene slurry polymerization reactor for preparing the ethylene polymer is as follows.

[0143] The method for preparing the ethylene polymer of the present invention includes performing batch or continuous ethylene slurry copolymerization while continuously supplying gaseous ethylene or liquid ethylene in the presence of hydrogen gas and gaseous or liquid comonomer in a single or a plurality of ethylene slurry reactors. This ethylene slurry polymerization reactor includes a single tank reactor having a stirring mechanism, a multi-stage tank reactor having a stirring mechanism and a configuration connected in series first, and a multi-stage reactor having a stirring mechanism and a configuration connected in parallel. A multi-stage tank reactor having a stirring mechanism and having a configuration that is first connected in series and then in parallel, a tank reactor having a stirring mechanism and having a configuration that is first connected in parallel and then in series, a tank reactor having a stirring mechanism and having a configuration that is first connected in series, then in parallel, and then in series, a tank reactor having a stirring mechanism and having a configuration that is first connected in parallel, then in series, and then in parallel, etc.; preferably, a single tank reactor having a stirring mechanism, a multi-stage tank reactor having a configuration connected in series, a multi-stage tank reactor having a configuration connected in parallel, a tank reactor having a configuration that is first connected in series and then in parallel, and more preferably, a single tank reactor having a stirring mechanism, a two-stage or three-stage tank reactor having a configuration connected in series, a two-stage tank reactor having a configuration connected in parallel, a three-stage tank reactor having a configuration that is first connected in series and then in parallel. Specifically, the description of the embodiments of ethylene tank slurry polymerization for preparing ethylene polymers is as follows.

[0144] When using batch copolymerization, a polyethylene main catalyst, a cocatalyst, a polymerization solvent, a comonomer, and hydrogen gas are first added to an ethylene slurry polymerization reactor in one shot according to the ratios described above. Next, ethylene gas is continuously introduced while maintaining the polymerization pressure and temperature constant. After the reaction is completed, the introduction of ethylene is stopped and the gas in the tank is evacuated. The slurry material in the tank is cooled to room temperature, discharged, filtered, and dried.

[0145] In the case of batch copolymerization, the respective ratios of the amounts of hydrogen gas and comonomer to ethylene are obtained by dividing the respective molar amounts of the hydrogen gas and comonomer added first by the total cumulative molar amount of ethylene added throughout the entire process from the start to the end of the reaction.

[0146] When continuous copolymerization is used, a polyethylene main catalyst, a cocatalyst, a polymerization solvent, a comonomer, hydrogen gas, and ethylene are continuously and simultaneously added to an ethylene slurry polymerization reactor according to the ratios described above. The reaction is carried out under a constant polymerization pressure and a constant polymerization temperature, and the material produced by the polymerization reaction also continuously exits from the ethylene slurry stirring tank and enters post-treatment processes such as degassing, solvent removal (such as flash evaporation, centrifugation, or filtration), drying, and pelletization (optional).

[0147] In the case of continuous copolymerization, the ratio of the amount of each of hydrogen gas and comonomer to ethylene refers to the ratio of the molar amount of each of hydrogen gas and comonomer to the molar amount of ethylene in the gas phase components of the reactor when the polymerization process is stable.

[0148] Specifically, the description of the stirring method and stirring speed for ethylene slurry polymerization for preparing an ethylene polymer is as follows.

[0149] The conditions for ethylene slurry polymerization having a stirring mechanism are not particularly limited in terms of the stirring method and stirring speed as long as the polyethylene main catalyst, cocatalyst, ethylene, hydrogen gas, comonomer, and slurry in the ethylene slurry reactor can be sufficiently stirred and dispersed. Generally speaking, as the stirring method, an anchor-type stirring paddle, a ribbon impeller-type stirring paddle, a paddle-type stirring paddle, a turbine-type stirring paddle, a propeller-type stirring paddle (rotating paddle type), and a frame-type stirring paddle can be used. When using a stirring paddle in an ethylene slurry polymerization reactor with a relatively large ratio of height to diameter (for example, greater than 2), a multi-layer stirring paddle can be used, and there is no special limitation on the stirring sealing method. Generally speaking, mechanical sealing or magnetic sealing can be used. When the volume of the ethylene slurry polymerization reactor is 10 m 3 or more, mechanical sealing is preferred. When the volume of the ethylene slurry polymerization reactor is 10 m 3If it is less than that, magnetic sealing is preferred. The stirring rotation speed is related to the volume of the ethylene slurry reactor and the stirring method. Generally speaking, when the reactor volume is relatively small (for example, 5 m 3 or less), or when using an anchor type stirring paddle, paddle type stirring paddle, turbine type stirring paddle, propeller type stirring paddle (rotating paddle type), etc., the required stirring rotation speed is relatively high, and the stirring rotation speed is 200 - 1000 rpm. When the reactor volume is relatively large (for example, more than 10 m 3 ), or when using a ribbon impeller type stirring paddle, frame type stirring paddle, etc., the required stirring rotation speed is relatively low, and the stirring rotation speed is 10 - 200 rpm. When the reactor volume is larger than 5 m 3 and less than 10 m 3 , the stirring rotation speed is 100 - 500 rpm.

[0150] The description of the ethylene slurry polymerization temperature for preparing an ethylene polymer is as follows.

[0151] According to the present invention, the ethylene slurry polymerization temperature for preparing an ethylene polymer is a polymerization slurry temperature of 30 - 110°C, preferably 50 - 100°C.

[0152] The polymerization temperature affects the polymerization activity, polymerization life, stability of instantaneous ethylene consumption, etc. of the polyethylene main catalyst, as well as the performance of the ethylene polymer prepared by ethylene slurry polymerization (for example, bulk density, true density, molecular weight and its distribution, copolymer sequence content, stability of quality such as composition and distribution). Generally speaking, at a higher polymerization temperature (for example, 65 - 110°C), the ethylene slurry polymerization activity of the polyethylene main catalyst is relatively high, and the polymerization life is relatively short, whereby the obtained ethylene polymer has a relatively low molecular weight and a relatively high melt index; on the other hand, at a lower polymerization temperature (for example, 30 - 65°C), the ethylene slurry polymerization activity of the polyethylene main catalyst is relatively low, and the polymerization life is relatively long, whereby the obtained ethylene polymer has a relatively high molecular weight and a relatively low melt index.

[0153] The coincidence temperature is mainly affected by the combined action of the heat released from the chain polymerization / combination of ethylene in the copolymerization reaction of ethylene and comonomer. The copolymerization reaction of ethylene and comonomer is carried out in a polymerization solvent in which a polyethylene main catalyst and a cocatalyst coexist. Heating or heat removal of the external jacket of the ethylene slurry reactor, or heating or heat removal of the internal coil pipe, or heating or heat removal of the slurry external circulation, heat removal of vapor-phase evaporation, or heat removal of the latent heat of phase change released in the conversion from the gas phase to the liquid phase, etc., heating or heat removal methods are used. Also, when preparing an ethylene polymer from an ethylene slurry, if it is difficult to stably control at a certain temperature, measures such as reducing the input amount of the polyethylene main catalyst, or stopping the input of the polyethylene main catalyst, or reducing the polymerization pressure, or increasing the molar ratio of hydrogen gas to ethylene are used to help control the polymerization temperature by lowering it, and prevent and avoid the occurrence of explosive polymerization phenomena such as aggregation and plasticization of the ethylene polymer caused by an uncontrolled polymerization temperature (for example, a temperature rising at 0.5 - 2 °C per minute within plus / minus 20 °C of the pre-set polymerization temperature). In the most extreme case, the polymerization pressure can be immediately released, or a small amount of an inactivator or terminator, such as carbon monoxide, carbon dioxide, ethanol, water vapor, or a mixture thereof, can be introduced to quench the ethylene slurry polymerization activity of the polyethylene main catalyst, and avoid the occurrence of explosive polymerization phenomena such as plasticization of the ethylene polymer caused by a temperature runaway of the polymerization temperature (for example, a temperature rising higher than 2 °C per minute within plus / minus 20 °C of the pre-set polymerization temperature).

[0154] Specifically, the description of the ethylene slurry polymerization pressure for preparing an ethylene polymer is as follows.

[0155] According to the present invention, the ethylene slurry polymerization pressure for preparing an ethylene polymer is the total pressure of the ethylene slurry polymerization reactor, which is determined by the partial pressures and vapor pressures of ethylene, cocatalyst, dissolved solvent, hydrogen gas, comonomer, polymerization solvent, etc., and optionally added inert gas at the polymerization temperature in the ethylene slurry polymerization reactor, and is 0.2 to 4.0 MPa, preferably 1.0 to 3.8 MPa. The polymerization pressure may also be 1.2 to 3.6 MPa.

[0156] Similar to the temperature of ethylene slurry polymerization, the polymerization pressure affects the polymerization activity, polymerization life, stability of instantaneous ethylene consumption, etc. of the polyethylene main catalyst, as well as the performance of the ethylene polymer prepared by ethylene slurry polymerization (e.g., bulk density, true density, molecular weight and its distribution, comonomer sequence content, stability of quality such as composition and distribution). Generally, at a higher polymerization pressure (e.g., 1.5 to 4.0 MPa), the ethylene slurry polymerization activity of the polyethylene main catalyst is relatively high; on the other hand, at a lower polymerization pressure (e.g., 0.2 to 1.5 MPa), the ethylene slurry polymerization activity of the polyethylene main catalyst is relatively low.

[0157] In the selection of the ethylene slurry polymerization pressure, various factors and conditions of the ethylene polymer need to be comprehensively considered. Generally speaking, when selecting an alkane solvent with a lower boiling point or a mixed alkane solvent with a higher vapor pressure at 20 °C as the polymerization solvent, by satisfying a higher polymerization pressure, the ethylene slurry polymerization activity of the polyethylene main catalyst can be exerted, and the polymerization cost can be reduced. According to the research of the present inventors, by using an alkane solvent with a boiling point of 5 to 55 °C such as n-pentane, neopentane, cyclopentane, isopentane, or a mixed alkane solvent with a saturated vapor pressure of 20 to 150 KPa at 20 °C as the polymerization solvent, it has been found that a polymerization pressure higher than 1.5 MPa can be satisfied. If the high polymerization pressure allows the ethylene slurry polymerization activity of the polyethylene main catalyst to be appropriately released, it can provide a sufficient selection space for the polymerization conditions for using a higher molar ratio of hydrogen gas to ethylene and a higher molar ratio of comonomer to ethylene. Furthermore, the polymerization process conditions for obtaining ethylene polymers with different molecular weights, different melt indices, different comonomer insertion rates, different true densities, etc. can be adjusted and controlled within a relatively wide range. At the same time, the present inventors unexpectedly found that an excessive polymerization pressure does not naturally bring about a high ethylene slurry polymerization activity of the polyethylene main catalyst. For example, it can be seen from a certain polymerization example that when the polymerization activity of the polyethylene main catalyst exceeds 4.0 MPa, it rapidly decreases, and there is almost no significant polymerization activity (polymerization activity: less than 1 KgPE / g polyethylene main catalyst) during the initial stage (0 to 1 hour) when the ethylene slurry polymerization is initiated.

[0158] Specifically, the description of the comonomer for ethylene slurry polymerization in the preparation of the ethylene polymer is as follows.

[0159] According to the present invention, the comonomer is selected from α-olefins, diolefins, cyclic olefins, and other olefinically unsaturated compounds.

[0160] Specifically, examples of the α-olefin include C3 to C10 α-olefins such as propene, 1-butene, 1-hexene, 1-heptylene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-undecene, 1-dodecene, styrene, and the like. Examples of the cyclic olefin include 1-cyclopentene, ethylidene norbornene, and norbornene. Examples of the diolefin include 1,4-butadiene, 2,5-pentadiene, 1,6-heptadiene, vinyl norbornene, norbornadiene, 1,7-octadiene, and the like. Examples of the other olefinic unsaturated compound include vinyl acetate, (meth)acrylate, and the like. Among them, the comonomer is preferably a C3 to C10 α-monoolefin, more preferably at least one of propene, 1-butene, 1-hexene, and 1-octene.

[0161] During the polymerization reaction, ethylene and the comonomer are charged into the polymerization tank together to carry out the polymerization reaction. In the present invention, "charging ethylene and the comonomer into the polymerization tank together" means supplying ethylene and the comonomer into the reaction tank together and carrying out the polymerization reaction together without the presence of a segmented polymerization step, that is, neither a segmented step of first polymerizing ethylene and then adding the comonomer for polymerization nor a segmented step of homogenizing the comonomer and then adding ethylene for polymerization exists. The obtained polyethylene has a random copolymer structure.

[0162] By copolymerizing ethylene with the above-described comonomer, the true density and crystallinity of the ethylene polymer can be decreased, and the mechanical properties (such as improvement in mechanical strength and toughness, and improvement in environmental stress crack resistance) can be enhanced.

[0163] According to the present invention, the molar ratio of comonomer to ethylene is 0.01 to 0.500:1, preferably 0.015 to 0.350:1. Within the range of the molar ratio of comonomer to ethylene provided by the present invention and under appropriate polymerization conditions such as a polyethylene main catalyst, it is possible to adjust and control the properties of the ethylene polymer such as melt index (for example, melt index at a load of 2.16 Kg at 190 ° C), true density, comonomer insertion rate, weight average molecular weight, molecular weight distribution, crystallinity, melting point, etc.

[0164] Next, the molar ratio of hydrogen gas to ethylene in ethylene slurry polymerization for preparing an ethylene polymer will be described.

[0165] Hydrogen, as a chain transfer agent and terminator for ethylene slurry polymerization, is mainly used to lower the melt index and molecular weight of the resulting ethylene polymer, and thus generates oligomers in the form of copolymerization. Generally speaking, an ethylene polymer obtained under ethylene slurry polymerization conditions with a high molar ratio of hydrogen to ethylene has a lower molecular weight and a higher melt index. Conversely, an ethylene polymer obtained under ethylene slurry polymerization conditions with a low molar ratio of hydrogen to ethylene has a higher molecular weight and a lower melt index. Under specific polymerization pressure conditions, the presence of hydrogen gas reduces the ethylene partial pressure, thereby reducing the ethylene slurry polymerization activity of the polyethylene main catalyst.

[0166] According to the research of the present inventors, when using a supported metallocene catalyst, a partially supported non-metallocene catalyst, and a partially supported post-transition metal catalyst as the polyethylene main catalyst, it was found that the ethylene slurry polymerization reaction is more sensitive to hydrogen gas.

[0167] According to the present invention, in ethylene slurry polymerization conditions, the molar ratio of hydrogen gas to ethylene is 0.01 to 20:1, preferably 0.015 to 10:1, more preferably 0.02 to 5:1.

[0168] In one embodiment of the present invention, when a non-metallocene catalyst is used as the main catalyst in slurry polymerization, the molar ratio of hydrogen gas to ethylene is 0.01 to 20:1, preferably 0.015 to 10:1, more preferably 0.02 to 5:1.

[0169] In one embodiment of the present invention, when a metallocene catalyst is used as the main catalyst in slurry polymerization, the molar ratio of hydrogen gas to ethylene is 0.01 to 0.15:1, preferably 0.015 to 0.1:1, more preferably 0.02 to 0.08:1.

[0170] In one embodiment of the present invention, when a Ziegler-Natta catalyst is used as the main catalyst in slurry polymerization, the molar ratio of hydrogen gas to ethylene is 0.01 to 20:1, preferably 0.015 to 10:1, more preferably 0.02 to 5:1.

[0171] Next, the molar ratio of comonomer to ethylene in ethylene slurry polymerization for preparing an ethylene polymer will be described.

[0172] The inventors have found that, under the comparative conditions and specific reaction conditions of the present invention, by adjusting the molar ratio of hydrogen gas to comonomer within a specific range, specific oligomers of the copolymer type can be generated during the polymerization reaction. Further, by combining with a specific polymerization solvent of the present invention, oligomers can be retained in the obtained ethylene polymer, and the processing performance of the ethylene polymer can be improved.

[0173] According to the present invention, in ethylene slurry polymerization conditions, the molar ratio of hydrogen gas to comonomer is 0.1 to 30:1, preferably 0.15 to 25:1, more preferably 0.2 to 23:1.

[0174] In one embodiment of the present invention, when a non-metallocene catalyst is used as the main catalyst in slurry polymerization, the molar ratio of hydrogen gas to comonomer is 8 to 30:1, preferably 10 to 25:1, more preferably 12 to 23:1.

[0175] In one embodiment of the present invention, when a metallocene catalyst is used as the main catalyst in slurry polymerization, the molar ratio of hydrogen gas to comonomer is 0.1 to 5:1, preferably 0.15 to 3:1, more preferably 0.2 to 2:1.

[0176] In one embodiment of the present invention, when a Ziegler-Natta catalyst is used as the main catalyst in slurry polymerization, the molar ratio of hydrogen gas to comonomer is 8 to 30:1, preferably 10 to 25:1, more preferably 12 to 23:1.

[0177] Also, the residence time of ethylene slurry polymerization for preparing an ethylene polymer is described as follows.

[0178] The present invention has no particular limitation on the polymerization residence time, and the polymerization residence time can be selected according to comprehensive conditions such as polymerization pressure, polymerization temperature, molar ratio of hydrogen gas to ethylene, molar ratio of comonomer to ethylene, polymerization activity of the polyethylene main catalyst, polymerization activity life, amount of the polyethylene main catalyst used, and slurry concentration. Generally speaking, when the polymerization activity is high, a shorter polymerization time can be selected. For example, based on the polyethylene main catalyst, when the ethylene slurry polymerization activity is less than 1 × 10 4 g of polyethylene / g of polyethylene main catalyst per hour, the polymerization residence time can be 1 to 12 hours, preferably 2 to 8 hours; when the ethylene slurry polymerization activity is 1 × 10 4 g of polyethylene / g of polyethylene main catalyst or more per hour but less than 3 × 10 4 g of polyethylene / g of polyethylene main catalyst per hour, the polymerization residence time can be 0.5 to 6 hours, preferably 1 to 4 hours; when the ethylene slurry polymerization activity is 3 × 10 4 g of polyethylene / g of polyethylene main catalyst or more per hour, the polymerization residence time can be 0.2 to 4 hours, preferably 0.5 to 2 hours, but is not limited thereto.

[0179] In addition, the description of the ethylene slurry concentration for preparing the ethylene polymer is as follows.

[0180] The slurry concentration of the ethylene polymer in ethylene slurry polymerization is an important index reflecting the degree of the ethylene slurry polymerization process. If the concentration is too low, the separation of the solvent and the material becomes a factor, and the preparation cost increases. If the concentration is too high, it is difficult to completely disperse by stirring. As a result, the heat transfer effect deteriorates, and thereby non-uniform materials are generated in the reactor, which is not useful for obtaining the ethylene polymer. According to the present invention, the slurry concentration of the ethylene polymer in the ethylene slurry polymerization reactor is 50 to 500 g of polyethylene / L polymerization solvent, preferably 100 to 400 g of polyethylene / L polymerization solvent.

[0181] In one embodiment of the present invention, an ethylene polymer is provided, wherein the average particle size is 50 to 3000 μm, the bulk density is 0.28 to 0.55 g / cm 3 and the true density is 0.920 to 0.980 g / cm 3 ; the melt index at a load of 2.16 Kg at 190 °C is 0 to 2000 g / 10 min, the crystallinity is 30 to 90%, the melting point is 105 to 147 °C, the comonomer molar insertion rate is 0 to 5 mol%, the weight average molecular weight is 1×10 4 g / mol to 150×10 4 g / mol, and the molecular weight distribution is 1.9 to 20.0.

[0182] In one embodiment of the present invention, an ethylene polymer is provided, wherein the average particle size is 100 to 1000 μm, the bulk density is 0.33 to 0.50 g / cm 3 and the true density is 0.930 to 0.960 g / cm 3 ; the melt index at a load of 2.16 Kg at 190 °C is 0 to 1000 g / 10 min, the crystallinity is 40 to 80%, the melting point is 110 to 143 °C, the comonomer molar insertion rate is 0 to 3.5 mol%, the weight average molecular weight is 2×10 4 g / mol to 150×10 4An ethylene polymer is provided, which has a molecular weight of [X] g / mol and a molecular weight distribution of 2.2 to 10.0.

[0183] In one embodiment of the present invention, a method for preparing an ethylene polymer is provided. In this method, batch or continuous ethylene slurry polymerization is carried out in an alkane solvent with a boiling point of 5 to 55 °C or a mixed alkane solvent with a saturated vapor pressure of 20 to 150 KPa (preferably 30 to 80 KPa) at 20 °C as the polymerization solvent, in the presence of a polyethylene catalyst system containing at least one of a non-metallocene catalyst, a metallocene catalyst, and a Ziegler-Natta type catalyst as the main catalyst. The polymerization temperature is 30 to 110 °C, the polymerization pressure is 0.2 to 4.0 MPa, the molar ratio of hydrogen gas to ethylene is 0 to 40:1, the molar ratio of comonomer to ethylene is 0 to 1:1, the ratio of the polyethylene main catalyst and the polymerization solvent is 0.001 to 0.500 mmol of the polyethylene main catalyst / L of the polymerization solvent, and the slurry concentration is 50 to 500 g of the polymer / L of the polymerization solvent.

[0184] In one embodiment of the present invention, a method for preparing an ethylene polymer is provided. In this method, batch or continuous ethylene slurry polymerization is carried out under the conditions that the polymerization temperature is 50 to 95 °C, the polymerization pressure is 0.5 to 3.0 MPa, the molar ratio of hydrogen gas to ethylene is 0.01 to 20:1, the molar ratio of comonomer to ethylene is 0.01 to 0.50:1, the ratio of the polyethylene main catalyst and the polymerization solvent is 0.005 to 0.200 mmol of the polyethylene main catalyst / L of the polymerization solvent, and the slurry concentration is 100 to 400 g of the polymer / L of the polymerization solvent.

[0185] The ethylene polymer provided in the present invention has excellent physical properties and processing performance, and can be applied to fields such as fibers, papermaking, food, chemical industry, packaging, agriculture, construction, medical treatment, filter cartridges for filtration devices, sports, entertainment, and the military.

[0186] Examples Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0187] The bulk density (g / cm 3 ) of the ethylene polymer is measured according to Standard GB 1636-79, and the true density (g / cm 3 ) of the ethylene polymer is determined in a density tube according to Standard GB / T 1033-86.

[0188] The content of the active metal element in the polyethylene main catalyst is determined by the ICP-AES method.

[0189] When using the batch ethylene slurry process, after the polymerization reaction is completed, the polymerization product in the reactor is filtered and dried, then the polymerization product is weighed, and the polymerization activity of the catalyst is represented by the ratio of the mass of the polymerization product divided by the mass of the polyethylene main catalyst used (kg ethylene polymer / g catalyst or kg PE / g Cat); when using a continuous ethylene slurry process, in an equivalent state (where the polymerization pressure, polymerization temperature, and gas phase composition remain stable), the instantaneous consumption rate of ethylene (also known as the absorption amount) is divided by the continuous addition rate of the polyethylene main catalyst to represent the polymerization activity of the catalyst (kilogram of ethylene polymer / gram of catalyst, or kg PE / g Cat).

[0190] The slurry concentration is calculated as follows. A sample is uniformly taken out from the ethylene slurry polymerization reactor, weighed, and recorded as m1 (gram), then completely dried to obtain a dry ethylene polymer m2 (gram). The density of the polymerization solvent is ρ (g / ml), and the slurry concentration is calculated according to the following formula.

[0191]

Equation

[0192] The measurement of the melt index of the ethylene polymer (at 190 °C; the load is 2.16 kg, or if specified otherwise, the load is 5 kg or 21.6 kg) is carried out in accordance with the standard GB / T 3682-2000 (g / 10 min).

[0193] The average particle size of the polymer is measured with a Microtrac S3500 laser particle size analyzer having a particle size measurement range of 0.01 to 10,000 microns.

[0194] The weight average molecular weight Mw (10 4 g / mol), number average molecular weight Mn (10 4 g / mol), and molecular weight distribution (MWD) of the ethylene polymer are measured using an Agilent GPC PL220 high-temperature gel chromatography analyzer. In the measurement, four Agilent PLgel Olexis chromatography columns are used, 1,2,4-trichlorobenzene is used as the mobile phase, the temperature during the measurement is 150 °C, and MWD = Mw / Mn (where Mw is the weight average molecular weight and Mn is the number average molecular weight) is calculated.

[0195] The determination of the comonomer content in the ethylene polymer is carried out by calibrating a copolymer with a known content using a Bruck Corporation 600M nuclear magnetic resonance apparatus and performing the measurement using a German Bruck Corporation 66 / S Fourier transform infrared spectrometer.

[0196] The determination of the crystallinity and melting point of the ethylene polymer is carried out using differential scanning calorimetry. The apparatus is a TA Corporation (USA) Q1000 DSC differential scanning calorimeter, and the measurement is carried out in accordance with the standard YYT0815-2010.

[0197] The measurement of the residual solvent amount in the wet material after the polymerization reaction is carried out as follows: The ethylene polymer powder obtained after the completion of the polymerization reaction is directly filtered through a 100-mesh filter screen, the wet polymer is weighed, and the mass is recorded as m1. Then, the wet polymer is completely dried under a vacuum of 20 mBar at 80 °C, the dried polymer powder is weighed, and the mass is recorded as m2. The residual solvent amount is calculated.

[0198] [Number]

[0199] The processing index in the film blowing test is determined as follows: The ethylene polymer is fed to the film blowing test carried out on a GOTTFERT Xtrude 1400 film blowing device. The main screw diameter is 45 mm, the ratio of length to diameter is 25, the die head diameter is 80 mm, and the die head gap is 0.8 mm. Circular air cooling is used, and the cooling air temperature is 20 °C. The screw rotation speed of the extruder is 20 rpm, the blowing expansion ratio is 2.3, the pulling speed is 8 m / min ± 0.5 m / min, the cooling line height is 230 mm - 250 mm, and the film thickness is 0.03 mm ± 0.003 mm.

[0200] In the film blowing test, the magnitude of the current (A) of the main machine reflects the processing index of the polymer in the blown film test.

[0201] The processing index in the blown film test reflects the processing performance of the polymer. That is, the lower the current of the main machine, the better the polymer processing performance. However, on the other hand, if this is too small, the extrusion pressure cannot be formed, and molding and processing cannot be carried out.

[0202] When the processing index in the film blowing test is less than 4.0, it indicates that the polymer is very easy to extrude during extrusion, it is difficult to form an effective extrusion pressure, and film blowing and molding cannot be carried out; when the processing index in the film blowing test exceeds 6.0, it indicates that the polymer is very difficult to extrude during extrusion, the extrusion pressure is too high, and it is difficult to carry out film blowing and processing; when the processing index in the film blowing test is between 4.0 and 6.0, it indicates that the extrusion pressure during the extrusion and processing of the polymer is appropriate and it is easy to carry out film blowing and processing; when the processing index in the film blowing test is between 4.0 and 6.0, the processing index decreases and the processing performance improves.

[0203] To better explain the ethylene polymer and its preparation method of the present invention, the following three catalysts are used as specific examples for the polyethylene main catalyst for ethylene slurry polymerization: The supported non-metallocene catalyst (CAT-1) is prepared according to Example 1 of Chinese Patent ZL200710162677.5, where the content of the active metal titanium element is 4.25% by weight.

[0204] The supported metallocene catalyst (CAT-2) is prepared according to Chinese Patent ZL201010521674.8, where the content of the active metal zirconium element is 0.62% by weight.

[0205] The Ziegler-Natta type catalyst (CAT-3) is prepared according to Example 1 of Chinese Patent ZL201010240378.0, where the content of the active metal titanium element is 9.5% by weight.

[0206] However, according to the present invention, the polyethylene main catalyst included therein includes, but is not limited to, the specific catalysts described above and should be under the jurisdiction of the claims.

[0207] Example 1 The polyethylene main catalyst was the supported non-metallocene catalyst CAT-1 (concentration 0.024 mmol / L), the co-catalyst was a triethylaluminum (TEAL) solution in pentane (concentration 1.0 mol / L), the polymerization pressure was 1.8 MPa, the polymerization temperature was 85 °C, the polymerization solvent was n-pentane (boiling point 36.1 °C) with a usage amount of 2.5 L, and the comonomer was 1-hexene.

[0208] A 5L anchor ethylene slurry polymerization tank (also called a polymerization autoclave) equipped with a stirrer was used. First, 2.5 L of the polymerization solvent was added to the polymerization autoclave at room temperature, and stirring was started at a rotation speed of 300 rpm. Next, a mixture of the polyethylene catalyst and the co-catalyst was added in one shot, then the comonomer was added in one shot, followed by the addition of hydrogen gas, and finally ethylene was continuously introduced to keep the polymerization pressure and temperature constant. After a 2-hour continuous reaction, the gas in the tank was exhausted, the polymer in the tank was discharged, and after drying, it was weighed to produce an ethylene polymer designated as PE-1. The preparation procedure and conditions of the ethylene polymer are shown in Table 1-1, and the properties of the ethylene polymer are shown in Table 1-2.

[0209] Example 1-1 It was basically the same as Example 1, but there were the following changes: The concentration of the polyethylene main catalyst was changed to 0.021 mmol / L, the co-catalyst was a triethylaluminum solution in cyclopentane (concentration 1.0 mol / L), the polymerization pressure was 1.2 MPa, the polymerization temperature was 95 °C, the polymerization solvent was cyclopentane (boiling point 49.26 °C) with a usage amount of 2.5 L, the comonomer was 1-octene, the rotation speed was 240 rpm, the polymerization time was 1.5 hours, and the ethylene polymer was designated as PE-1-1. The preparation procedure and conditions of the ethylene polymer are shown in Table 1-1, and the properties of the ethylene polymer are shown in Table 1-2.

[0210] Example 1-2 It was basically the same as Example 1, but there were the following changes: The concentration of the polyethylene main catalyst was changed to 0.028 mmol / L. The cocatalyst was a solution of triethylaluminum in 2-methylbutane (also known as isopentane) with a concentration of 1 mol / L. The polymerization pressure was 2.4 MPa, the polymerization temperature was 78 °C, the polymerization solvent was isopentane (boiling point 27.83 °C) with a usage amount of 2.5 L. The rotation speed was 200 rpm. After a polymerization time of 3 hours, the gas in the tank was evacuated, the polymer in the tank was released, and after drying, it was weighed to produce an ethylene polymer designated as PE-1-2. The preparation procedures and conditions of the ethylene polymer are shown in Table 1-1, and the properties of the ethylene polymer are shown in Table 1-2.

[0211] Example 1-3 It was basically the same as Example 1, but there were the following changes: The cocatalyst was a solution of triisobutylaluminum (TIBA) in neopentane with a concentration of 2.0 mol / L. The polymerization pressure was 3.6 MPa, the polymerization temperature was 62 °C, the polymerization solvent was neopentane (boiling point 9.5 °C) with a usage amount of 2.5 L, the comonomer was 1-butene, the rotation speed was 40 rpm, the polymerization time was 1 hour, and the ethylene polymer was designated as PE-1-3. The preparation procedures and conditions of the ethylene polymer are shown in Table 1-1, and the properties of the ethylene polymer are shown in Table 1-2.

[0212] Example 1-4 It was basically the same as Example 1, but there were the following changes: The polymerization solvent was a mixed alkane solvent composed of n-pentane and isopentane according to a molar ratio of 1:1 and having a saturated vapor pressure of 66.6 KPa at 20 °C. The solvent used for the cocatalyst was also the same mixed alkane solvent.

[0213] The ethylene polymer was designated as PE-1-4. The preparation procedures and conditions of the ethylene polymer are shown in Table 1-1, and the properties of the ethylene polymer are shown in Table 1-2.

[0214] Example 1-5 It was basically the same as Example 1, but there were the following changes: The overlapping solvent was a mixed alkane solvent composed of neopentane and isopentane according to a molar ratio of 0.5:1, and had a saturated vapor pressure of 100.01 KPa at 20°C. The solvent used for the cocatalyst was also the same mixed alkane solvent.

[0215] The ethylene polymer was designated as PE-1-5. The preparation procedures and conditions of the ethylene polymer are shown in Table 1-1, and the properties of the ethylene polymer are shown in Table 1-2.

[0216] Examples 1-6 It was basically the same as Example 1, but there were the following changes: The overlapping solvent was a mixed alkane solvent composed of isopentane and cyclopentane according to a molar ratio of 8:1, and had a saturated vapor pressure of 72.02 KPa at 20°C. The solvent used for the cocatalyst was also the same mixed alkane solvent.

[0217] The ethylene polymer was designated as PE-1-6. The preparation procedures and conditions of the ethylene polymer are shown in Table 1-1, and the properties of the ethylene polymer are shown in Table 1-2.

[0218] Comparative Example 1-1 It was basically the same as Example 1, but there were the following changes: The overlapping solvent was changed to a hexane solvent, the solvent of the cocatalyst was changed to a hexane solution, and the ethylene polymer was designated as CPE-1-1. The preparation procedures and conditions of the ethylene polymer are shown in Table 1-1, and the properties of the ethylene polymer are shown in Table 1-2.

[0219] Comparative Example 1-2 It was basically the same as Example 1-3, but there were the following changes: The overlapping solvent was changed to a hexane solvent, the solvent of the cocatalyst was changed to a hexane solution, and the ethylene polymer was designated as CPE-1-2. The preparation procedures and conditions of the ethylene polymer are shown in Table 1-1, and the properties of the ethylene polymer are shown in Table 1-2.

[0220] Comparative Example 1-3 It was basically the same as Example 1, but there were the following changes: Hydrogen gas was not added, the molar ratio of comonomer 1-hexene to ethylene was 1, and the catalyst concentration was 0.007 mmol / L.

[0221] The ethylene polymer was designated as CPE-1-3. The preparation procedures and conditions of the ethylene polymer are shown in Table 1-1, and the properties of the ethylene polymer are shown in Table 1-2. The polymer could not be molded and adhered severely to the tank.

[0222] Comparative Example 1-4 It was basically the same as Example 1, but there were the following changes: Hydrogen gas and comonomer were not added, that is, the molar ratio of hydrogen gas to ethylene was 0, the molar ratio of comonomer to ethylene was 0, the polymerization time was 8 hours, and the catalyst concentration was 0.007 mmol / L.

[0223] The ethylene polymer was designated as CPE-1-4. The preparation procedures and conditions of the ethylene polymer are shown in Table 1-1, and the properties of the ethylene polymer are shown in Table 1-2. The polymer had such a high molecular weight that Mw and Mn could not be measured by GPC and could not be processed by extrusion.

[0224] Comparative Example 1-5 It was basically the same as Example 1, but there were the following changes: The molar ratio of hydrogen gas to ethylene was 30, comonomer was not added, that is, the molar ratio of comonomer to ethylene was 0, and the catalyst concentration was changed to 0.180 mmol / L.

[0225] The ethylene polymer was designated as CPE-1-5. The preparation procedures and conditions of the ethylene polymer are shown in Table 1-1, and the properties of the ethylene polymer are shown in Table 1-2. The polymer had a high melt index and an extremely low molecular weight and could not be processed into a shape by extrusion molding.

[0226] Comparative Examples 1-6 It was basically the same as Example 1, but there were the following changes: The molar ratio of hydrogen gas to the comonomer was 0.05, and the catalyst concentration was changed to 0.180 mmol / L.

[0227] The ethylene polymer was designated as CPE-1-6. The preparation procedures and conditions of the ethylene polymer are shown in Table 1-1, and the properties of the ethylene polymer are shown in Table 1-2. The polymer could not be molded and adhered severely to the tank.

[0228] Comparative Example 1-7 It was basically the same as Example 1, but there were the following changes: The molar ratio of hydrogen gas to the comonomer was 40.

[0229] The ethylene polymer was designated as CPE-1-7. The preparation procedures and conditions of the ethylene polymer are shown in Table 1-1, and the properties of the ethylene polymer are shown in Table 1-2.

[0230] Example 2 It was basically the same as Example 1, but there were the following changes: The polyethylene main catalyst used was the supported metallocene catalyst CAT-2, the cocatalyst was changed to a solution of methylaluminoxane (MAO) in n-pentane (concentration 10 wt%), the concentration of the polyethylene main catalyst was changed to 0.005 mmol / L, the molar ratio of hydrogen gas to ethylene was changed to 0.05, and the ethylene polymer was designated as PE-2. The preparation procedures and conditions of the ethylene polymer are shown in Table 2-1, and the properties of the ethylene polymer are shown in Table 2-2.

[0231] Example 2-1 It was basically the same as Example 1-1, but there were the following changes: The supported metallocene catalyst CAT-2 was used as the polyethylene main catalyst, the cocatalyst was changed to a solution of methylaluminoxane in cyclopentane (concentration 30 wt%), the concentration of the polyethylene main catalyst was changed to 0.005 mmol / L, the molar ratio of hydrogen gas to ethylene was 0.02, the molar ratio of comonomer to ethylene was 0.02, and the ethylene polymer was designated as PE-2-1. The preparation procedures and conditions of the ethylene polymer are shown in Table 2-1, and the properties of the ethylene polymer are shown in Table 2-2.

[0232] Example 2-2 It was basically the same as Example 1-2, but there were the following changes: The supported metallocene catalyst CAT-2 was used as the polyethylene main catalyst, the cocatalyst was changed to a solution of triisobutylaluminum in isopentane (concentration 1 mol / L), the concentration of the polyethylene main catalyst was changed to 0.015 mmol / L, the molar ratio of hydrogen gas to ethylene was 0.07:1, and the ethylene polymer was designated as PE-2-2. The preparation procedures and conditions of the ethylene polymer are shown in Table 2-1, and the properties of the ethylene polymer are shown in Table 2-2.

[0233] Example 2-3 It was basically the same as Example 1-3, but there were the following changes: The supported metallocene catalyst CAT-2 was used as the polyethylene main catalyst, the cocatalyst was changed to a solution of methylaluminoxane in neopentane (concentration 10 wt%), the concentration of the polyethylene main catalyst was changed to 0.005 mmol / L, the molar ratio of hydrogen gas to ethylene was 0.04:1, and the ethylene polymer was designated as PE-2-3. The preparation procedures and conditions of the ethylene polymer are shown in Table 2-1, and the properties of the ethylene polymer are shown in Table 2-2.

[0234] Example 2-4 It was basically the same as Example 2, but there were the following changes: The overlapping solvent is a mixed alkane solvent composed of n-pentane, isopentane, and cyclopentane according to a molar ratio of 1:1:1, with a saturated vapor pressure of 55.93 KPa at 20°C. The solvent used for the cocatalyst is also the same mixed alkane solvent (concentration 10 wt%). The concentration of the polyethylene main catalyst is 0.005 mmol / L, the molar ratio of hydrogen gas to ethylene is 0.05:1, and the ethylene polymer is designated as PE-2-4. The preparation procedures and conditions of the ethylene polymer are shown in Table 2-1, and the properties of the ethylene polymer are shown in Table 2-2.

[0235] Example 2-5 It was basically the same as Example 2, but there were the following changes: The overlapping solvent was a mixed alkane solvent composed of neopentane and isopentane according to a molar ratio of 0.5:1, with a saturated vapor pressure of 100.01 KPa at 20°C. The solvent used for the cocatalyst was also the same mixed alkane solvent.

[0236] The ethylene polymer was designated as PE-2-5. The preparation procedures and conditions of the ethylene polymer are shown in Table 2-1, and the properties of the ethylene polymer are shown in Table 2-2.

[0237] Example 2-6 It was basically the same as Example 2, but there were the following changes: The overlapping solvent was a mixed alkane solvent composed of isopentane and cyclopentane according to a molar ratio of 8:1, with a saturated vapor pressure of 72.02 KPa at 20°C. The solvent used for the cocatalyst was also the same mixed alkane solvent.

[0238] The ethylene polymer was designated as PE-2-6. The preparation procedures and conditions of the ethylene polymer are shown in Table 2-1, and the properties of the ethylene polymer are shown in Table 2-2.

[0239] Comparative Example 2-1 It was basically the same as Example 2, but there were the following changes: The overlapping solvent was changed to a hexane solvent, the solvent for the cocatalyst was changed to a hexane solution, and the ethylene polymer was designated as CPE-2-1. The preparation procedures and conditions of the ethylene polymer are shown in Table 2-1, and the properties of the ethylene polymer are shown in Table 2-2.

[0240] Comparative Example 2-2 It was basically the same as Example 2-3, but there were the following changes: The overlapping solvent was changed to a hexane solvent, the solvent for the cocatalyst was changed to a hexane solution, and the ethylene polymer was designated as CPE-2-2. The preparation procedures and conditions of the ethylene polymer are shown in Table 2-1, and the properties of the ethylene polymer are shown in Table 2-2.

[0241] Comparative Example 2-3 It was basically the same as Example 2, but there were the following changes: Hydrogen gas was not added, and the molar ratio of comonomer 1-hexene to ethylene was 1.

[0242] The ethylene polymer was designated as CPE-2-3. The preparation procedures and conditions of the ethylene polymer are shown in Table 2-1, and the properties of the ethylene polymer are shown in Table 2-2. The polymer could not be molded and adhered severely to the tank.

[0243] Comparative Example 2-4 It was basically the same as Comparative Example 1-4, but there were the following changes: Hydrogen gas and comonomer were not added, that is, the molar ratio of hydrogen gas to ethylene was 0, the molar ratio of comonomer to ethylene was 0, the polymerization time was 8 hours, the polyethylene main catalyst used was the supported metallocene catalyst CAT-2, the concentration of the polyethylene main catalyst was changed to 0.002 mmol / L, and the ethylene polymer was designated as CPE-2-4. The preparation procedures and conditions of the ethylene polymer are shown in Table 2-1, and the properties of the ethylene polymer are shown in Table 2-2. The polymer had such a high molecular weight that Mw and Mn could not be measured by GPC and could not be processed by extrusion.

[0244] Comparative Example 2-5 It was basically the same as Example 2, but there were the following changes: The molar ratio of hydrogen gas to ethylene was 30, no comonomer was added, that is, the molar ratio of comonomer to ethylene was 0, and the catalyst concentration was changed to 0.200 mmol / L.

[0245] The ethylene polymer was designated as CPE-2-5. The preparation procedures and conditions of the ethylene polymer are shown in Table 2-1, and the properties of the ethylene polymer are shown in Table 2-2. The polymer had a high melt index and an extremely low molecular weight and could not be processed into a shape by extrusion molding.

[0246] Comparative Example 2-6 It was basically the same as Example 2, but there were the following changes: The molar ratio of hydrogen gas to comonomer was 0.01, and the catalyst concentration was changed to 0.200 mmol / L.

[0247] The ethylene polymer was designated as CPE-2-6. The preparation procedures and conditions of the ethylene polymer are shown in Table 2-1, and the properties of the ethylene polymer are shown in Table 2-2. The polymer could not be molded and adhered severely to the tank.

[0248] Example 3 It was basically the same as Example 1, but there were the following changes: The polyethylene main catalyst used was a Ziegler-Natta type catalyst CAT-3, the concentration of the polyethylene main catalyst was changed to 0.024 mmol / L, and the ethylene polymer was designated as PE-3. The preparation procedures and conditions of the ethylene polymer are shown in Table 3-1, and the properties of the ethylene polymer are shown in Table 3-2.

[0249] Example 3-1 It was basically the same as Example 1-1, but there were the following changes: The polyethylene main catalyst used was the Ziegler-Natta type catalyst CAT-3. The concentration of the polyethylene main catalyst was changed to 0.018 mmol / L, the polymerization time was changed to 0.5 hours, and the ethylene polymer was designated as PE-3-1. The preparation procedures and conditions of the ethylene polymer are shown in Table 3-1, and the properties of the ethylene polymer are shown in Table 3-2.

[0250] Example 3-2 It was basically the same as Example 1-2, but there were the following changes: The polyethylene main catalyst used was the Ziegler-Natta type catalyst CAT-3. The concentration of the polyethylene main catalyst was changed to 0.048 mmol / L, and the ethylene polymer was designated as PE-3-2. The preparation procedures and conditions of the ethylene polymer are shown in Table 3-1, and the properties of the ethylene polymer are shown in Table 3-2.

[0251] Example 3-3 It was basically the same as Example 1-3, but there were the following changes: The polyethylene main catalyst used was the Ziegler-Natta type catalyst CAT-3. The cocatalyst was changed to a solution of tri-iso-butylaluminum in neopentane (TIBA, concentration 1 mol / L), the concentration of the polyethylene main catalyst was changed to 0.012 mmol / L, and the ethylene polymer was designated as PE-3-3. The preparation procedures and conditions of the ethylene polymer are shown in Table 3-1, and the properties of the ethylene polymer are shown in Table 3-2.

[0252] Example 3-4 It was basically the same as Example 1-4, but there were the following changes: The polyethylene main catalyst used was the Ziegler-Natta type catalyst CAT-3. The polymerization solvent was a mixed alkane solvent composed of neopentane and isopentane according to a molar ratio of 0.5:1 and having a saturated vapor pressure of 100.01 KPa at 20°C. The solvent used for the cocatalyst was also the same mixed alkane solvent. The concentration of the polyethylene main catalyst was changed to 0.024 mmol / L, and the ethylene polymer was designated as PE-3-4. The preparation procedures and conditions of the ethylene polymer are shown in Table 3-1, and the properties of the ethylene polymer are shown in Table 3-2.

[0253] Example 3-5 It was basically the same as Example 3, but there were the following changes: The concentration of the polyethylene main catalyst was changed to 0.018 mmol / L. The polymerization solvent was a mixed alkane solvent composed of neopentane and isopentane according to a molar ratio of 0.5:1 and having a saturated vapor pressure of 100.01 KPa at 20°C. The solvent used for the cocatalyst was also the same mixed alkane solvent.

[0254] The ethylene polymer was designated as PE-3-5. The preparation procedures and conditions of the ethylene polymer are shown in Table 3-1, and the properties of the ethylene polymer are shown in Table 3-2.

[0255] Example 3-6 It was basically the same as Example 3, but there were the following changes: The concentration of the polyethylene main catalyst was changed to 0.018 mmol / L. The polymerization solvent was a mixed alkane solvent composed of isopentane and cyclopentane according to a molar ratio of 8:1 and having a saturated vapor pressure of 72.02 KPa at 20°C. The solvent used for the cocatalyst was also the same mixed alkane solvent.

[0256] The ethylene polymer was designated as PE-3-6. The preparation procedures and conditions of the ethylene polymer are shown in Table 3-1, and the properties of the ethylene polymer are shown in Table 3-2.

[0257] Comparative Example 3-1 It was basically the same as Example 3, but there were the following changes: The polymerization solvent was changed to a hexane solvent, the solvent for the cocatalyst was changed to a hexane solution, and the ethylene polymer was designated as CPE-3-1. The preparation procedures and conditions of the ethylene polymer are shown in Table 3-1, and the properties of the ethylene polymer are shown in Table 3-2.

[0258] Comparative Example 3-2 It was basically the same as Example 3-3, but there were the following changes: The polymerization solvent was changed to a hexane solvent, the solvent for the cocatalyst was changed to a hexane solution, and the ethylene polymer was designated as CPE-3-2. The preparation procedures and conditions of the ethylene polymer are shown in Table 3-1, and the properties of the ethylene polymer are shown in Table 3-2.

[0259] Comparative Example 3-3 It was basically the same as Example 3, but there were the following changes: Hydrogen gas was not added, the molar ratio of comonomer 1-hexene to ethylene was 1, and the catalyst concentration was changed to 0.008 mmol / L.

[0260] The ethylene polymer was designated as CPE-3-3. The preparation procedures and conditions of the ethylene polymer are shown in Table 3-1, and the properties of the ethylene polymer are shown in Table 3-2. The polymer could not be molded and adhered severely to the tank.

[0261] Comparative Example 3-4 It was basically the same as Comparative Examples 1 to 4, but there were the following changes: Hydrogen gas and comonomer were not added, that is, the molar ratio of hydrogen gas to ethylene was 0, the molar ratio of comonomer to ethylene was 0, the polymerization time was 8 hours, and the catalyst concentration was changed to 0.008 mmol / L.

[0262] The polyethylene main catalyst used was the Ziegler-Natta type catalyst CAT-3, and the ethylene polymer was designated as CPE-3-4. The preparation procedures and conditions of the ethylene polymer are shown in Table 3-1, and the properties of the ethylene polymer are shown in Table 3-2. The polymer had a very high molecular weight such that Mw and Mn could not be measured by GPC and could not be processed by extrusion.

[0263] Comparative Example 3-5 It was basically the same as Example 3, but there were the following changes: The molar ratio of hydrogen gas to ethylene was 30, no comonomer was added, that is, the molar ratio of comonomer to ethylene was 0, and the catalyst concentration was changed to 0.48 mmol / L.

[0264] The ethylene polymer was designated as CPE-3-5. The preparation procedures and conditions of the ethylene polymer are shown in Table 3-1, and the properties of the ethylene polymer are shown in Table 3-2. The polymer had a high melt index and an extremely low molecular weight and could not be processed into a shape by extrusion molding.

[0265] Comparative Example 3-6 It was basically the same as Example 3, but there were the following changes: The molar ratio of hydrogen gas to comonomer was 0.05, and the catalyst concentration was changed to 0.180 mmol / L.

[0266] The ethylene polymer was designated as CPE-3-6. The preparation procedures and conditions of the ethylene polymer are shown in Table 3-1, and the properties of the ethylene polymer are shown in Table 3-2. The polymer could not be molded and adhered severely to the tank.

[0267] Comparative Example 3-7 It was basically the same as Example 3, but there were the following changes: The concentration of the polyethylene main catalyst was changed to 0.024 mmol / L, and the molar ratio of hydrogen gas to comonomer was 40.

[0268] The ethylene polymer was designated as CPE-3-7. The preparation procedures and conditions of the ethylene polymer are shown in Table 3-1, and the properties of the ethylene polymer are shown in Table 3-2.

[0269] Assay The ethylene polymers obtained in the examples and comparative examples were subjected to a film blowing test using a GOTTFERT Xtrude 1400 film blowing apparatus. The main screw diameter was 45 mm, the ratio of length to diameter was 25, the die head diameter was 80 mm, and the die head gap was 0.8 mm. Circular air cooling was used, and the cooling air temperature was controllable (the cooling air temperature was 20 °C). The screw rotation speed of the extruder was 20 rpm, the blowing expansion ratio was 2.3, the pulling speed was 8 m / min ± 0.5 m / min, the height of the cooling line was 230 mm to 250 mm, and the film thickness was 0.03 mm ± 0.003 mm. The current of each main machine was measured (unit: A) and used as the processing index in the film blowing test.

[0270] [Table 1] JPEG0007690042000021.jpg241169

[0271] [Table 2] JPEG0007690042000023.jpg244169

[0272] [Table 3] JPEG0007690042000025.jpg244169

[0273] [Table 4] JPEG0007690042000027.jpg234169

[0274] [Table 5] JPEG0007690042000029.jpg236169

[0275]

Table 6

[0276] From the comparison of the results obtained from Example 1 in the above table with the results obtained from Comparative Examples 1-5, the comparison of the results obtained from Example 2 with the results obtained from Comparative Examples 2-5, and the comparison of the results obtained from Example 3 with the results obtained from Comparative Examples 3-5, it can be seen that the copolymerization effect of the catalyst is remarkable, that is, the catalyst has a higher copolymerization activity than the homopolymerization activity; the copolymerization reaction can increase the bulk density of the polymer, that is, improve the particle morphology of the polymer and reduce the true density, melting point, and crystallinity of the polymer; it can be understood that the high-density polyethylene obtained by the present invention has excellent processing performance.

[0277] From the comparison of the results obtained from Example 1 and Examples 1-3 in the above table with the results obtained from Comparative Examples 1-1 and Comparative Examples 1-2; the comparison of the results obtained from Example 2 and Examples 2-3 with the results obtained from Comparative Examples 2-1 and Comparative Examples 2-2; the comparison of the results obtained from Example 3 and Examples 3-3 with the results obtained from Comparative Examples 3-1 and Comparative Examples 3-2, it can be seen that when using the ethylene slurry polymerization method of the present invention, the ethylene polymer powder obtained after polymerization is very easy to dry. After the polymerization reaction is completed, the product is directly filtered, and the residual solvent content in the wet polymer is less than 20% by weight, which is lower than the residual solvent content exceeding 25% by weight in the wet polymer obtained by using hexane as the polymerization solvent. This has been very helpful in shortening the drying time of the polyethylene material and saving the cost of polyethylene post-treatment.

[0278] Comparing the examples and comparative examples in the above table, it can be seen that the polyethylene obtained by the ethylene slurry polymerization method of the present invention has an appropriate processing index in the film blowing test and exhibits excellent processing performance. This indicates that the ethylene polymer obtained by the method of the present invention has excellent processing performance, which is very useful for subsequent processing applications. Under the same conditions, it can further reduce the processing cost or improve the processing efficiency of polyethylene with the same main machine current.

[0279] From the data and effects obtained in the above table, it can be seen that the ethylene polymer provided by the present invention has a high bulk density, and the true density, melt index, crystallinity, melting point, comonomer molar insertion rate, weight average molecular weight, etc. are widely adjustable and have a controllable range, and also have a moderately adjustable and controllable molecular weight distribution. The performance of the ethylene polymer can be adjusted and controlled by simply and flexibly changing the polymerization process parameters such as the polyethylene main catalyst, the ratio of the polyethylene main catalyst and the cocatalyst, the molar ratio of hydrogen gas to ethylene, the molar ratio of comonomer to ethylene, the polymerization pressure, the polymerization temperature, and the polymerization time. The obtained high-density polyethylene exhibits excellent processing performance and is very suitable for the technical production and application of ethylene slurry polymerization.

[0280] As described above, the embodiments of the present invention have been described in detail with reference to the examples. However, the scope of the present invention is not limited to the above embodiments, but is defined by the claims. It is obvious that those skilled in the art can appropriately change the embodiments without departing from the technical idea and technical scope of the present invention, and the changed embodiments are also included in the scope of the present invention.

Claims

1. A method for preparing a high-density ethylene polymer, wherein the true density of the ethylene polymer is 0.930 to 0.980 g / cm3, A raw material containing ethylene, hydrogen gas and a comonomer is subjected to tank-type slurry polymerization using a mixed alkane solvent having a saturation vapor pressure at 20 ° C. of 20 to 150 kPa as a polymerization solvent in the presence of a polyethylene catalyst system, wherein the molar ratio of the hydrogen gas to the ethylene is 0.01 to 20:1 and the molar ratio of the hydrogen gas to the comonomer is 0.1 to 30:1, and the comonomer is C ３ -C １０ selected from α-olefins, the polyethylene catalyst system includes a polyethylene main catalyst selected from at least one of a non-metallocene catalyst, a metallocene catalyst, and a Ziegler-type catalyst, the polymerization solvent is selected from mixed alkane solvents having a saturated vapor pressure of 20 to 150 kPa at 20 °C, and the mixed alkane solvent is formed by mixing two or more alkanes selected from n-pentane, isopentane, neopentane, and cyclopentane, Method.

2. The method for preparing an ethylene polymer according to claim 1, wherein the polymerization temperature is 30 to 110 °C, the polymerization pressure is 0.2 to 4.0 MPa, and the molar ratio of comonomer to ethylene is 0.01 to 0.500:

1.

3. The ratio of the polyethylene main catalyst to the polymerization solvent is 0.001 to 0.500 mmol of polyethylene main catalyst / 1 L of polymerization solvent, the slurry concentration is 50 to 500 g of polymer / 1 L of polymerization solvent, the tank-type slurry polymerization is carried out batchwise or continuously, and the solvent content in the powder material obtained after flash evaporation, filtration or centrifugation of the slurry is less than 20% by weight. The method for preparing an ethylene polymer according to claim 1 or 2.

4. The method for preparing an ethylene polymer according to claim 1, wherein the polymerization solvent is selected from one of the combinations of n-pentane and isopentane, isopentane and neopentane, n-pentane and cyclopentane, n-pentane and neopentane, isopentane and cyclopentane, neopentane and cyclopentane, and the combination of n-pentane-isopentane-cyclopentane.

5. The polyethylene main catalyst is selected from a supported non-metallocene catalyst, a supported metallocene catalyst, a Ziegler-type catalyst, a Ziegler-Natta-type catalyst, or a mixture of these catalysts, the polyethylene catalyst system includes a cocatalyst, and the cocatalyst is selected from aluminoxane, alkylaluminum, haloalkylaluminum, fluoroborane, alkylborane, or alkylammonium borate, or a mixture of two or more of these, Here, When the non-metallocene catalyst is used as the main catalyst, the molar ratio of hydrogen gas to comonomer is 8 to 30:1, and the molar ratio of hydrogen gas to ethylene is 0.01 to 20:1; When the metallocene catalyst is used as the main catalyst, the molar ratio of hydrogen gas to comonomer is 0.1 to 5:1, and the molar ratio of hydrogen gas to ethylene is 0.01 to 0.15:1; When the Ziegler-Natta type catalyst is used as the main catalyst, the molar ratio of hydrogen gas to comonomer is 8 to 30:1, and the molar ratio of hydrogen gas to ethylene is 0.01 to 20:1, characterized in that The method for preparing an ethylene polymer according to claim 1.

6. The method for preparing an ethylene polymer according to claim 1, wherein the polyethylene main catalyst is selected from a supported non-metallocene catalyst and a Ziegler-Natta type catalyst, and the activating metal element thereof is selected from Group IVB metal elements.

7. The method for preparing an ethylene polymer according to claim 1, characterized by satisfying one or more of the following requirements: The true density of the ethylene polymer is 0.942 to 0.970 g / cm3, The molar ratio of the hydrogen gas to the ethylene is 0.015 to 10:1, and the molar ratio of the hydrogen gas to the comonomer is 0.15 to 25:1, The polymerization temperature is 50 to 100 °C, the polymerization pressure is 1.0 to 3.8 MPa, the molar ratio of the comonomer to the ethylene is 0.015 to 0.350:1, The ratio of the polyethylene main catalyst to the polymerization solvent is 0.005 to 0.200 mmol of polyethylene main catalyst / polymerization solvent 1 L, and the slurry concentration is 100 to 400 g of polymer / polymerization solvent 1 L, The polyethylene catalyst system contains a cocatalyst, and the cocatalyst is selected from methylaluminoxane, ethylaluminoxane, modified methylaluminoxane, trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, monochlorodiethylaluminum, and dichloroethylaluminum, When the non-metallocene catalyst is used as the main catalyst, the molar ratio of hydrogen gas to comonomer is 12 to 23:1, and the molar ratio of hydrogen gas to ethylene is 0.02 to 5:1; When using the metallocene catalyst as the main catalyst, the molar ratio of hydrogen gas to comonomer is 0.2 to 2:1, and the molar ratio of hydrogen gas to ethylene is 0.02 to 0.08:1; When using the Ziegler-Natta type catalyst as the main catalyst, the molar ratio of hydrogen gas to comonomer is 12 to 23:1, and the molar ratio of hydrogen gas to ethylene is 0.02 to 5:1, The polyethylene main catalyst is selected from a supported non-metallocene catalyst and a Ziegler-Natta type catalyst, and its activating metal element is selected from Group IVB metal elements, Method.

8. Regarding the total aluminum element in aluminoxane, alkylaluminum, or haloalkylaluminum in the cocatalyst, and the activating metal element in the polyethylene main catalyst, the molar ratio of aluminum to activating metal is 10 to 500:1, Regarding the boron element in fluoroborane, alkylborane, or alkylammonium borate in the cocatalyst, and the activating metal element in the polyethylene main catalyst, the molar ratio of boron to activating metal is 1 to 50:1, Regarding the total aluminum element in aluminoxane, alkylaluminum, or haloalkylaluminum in the cocatalyst, the boron element in fluoroborane, alkylborane, or alkylammonium borate, and the activating metal atoms in the polyethylene main catalyst, the molar ratio of aluminum:boron:activating metal is 10 to 100:1 to 20:1, characterized in that The method for preparing an ethylene polymer according to claim 5.

9. Regarding the total aluminum element in aluminoxane, alkylaluminum, or haloalkylaluminum in the cocatalyst, and the activating metal element in the polyethylene main catalyst, the molar ratio of aluminum to activating metal is 20 to 100:1, Regarding the boron element in fluoroborane, alkylborane, or alkylammonium borate in the cocatalyst, and the activating metal element in the polyethylene main catalyst, the molar ratio of boron to activating metal is 1 to 20:1, Regarding the total aluminum element in the cocatalyst, aluminoxane, alkylaluminum, or haloalkylaluminum, the boron element in fluoroborane, alkylborane, or alkylammonium borate, and the activated metal atom in the polyethylene main catalyst, the molar ratio of aluminum:boron:activated metal is 20 to 50:1 to 10:1, characterized in that The method for preparing an ethylene polymer according to claim 8.

10. wherein the comonomer is selected from C ３ to C １０ α-olefins, and the method for preparing an ethylene polymer according to claim 1.

11. The method for preparing an ethylene polymer according to claim 1, characterized in that the comonomer is one or more of propylene, 1-butene, 1-hexene, and 1-octene.

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