Method for continuous polymerization of ethylene and alpha-olefin

Abstract

The invention belongs to the technical field of olefin polymerization, and particularly relates to a method for continuous polymerization of ethylene and alpha-olefin. According to the method, the feeding temperature of the raw materials is 10-30 DEG C; the temperature of the polymerization reaction is 120-150 DEG C; the ratio of the raw material heat removal amount to the polymerization reaction heat exchange amount is Q, and Q is more than 50% and less than 85%; ; xc is the mass ratio of the structural unit from the alpha-olefin monomer in the polymer, Tr is the temperature value of the polymerization reaction by taking DEG C as the unit, Ta is the feeding temperature value of the raw material by taking DEG C as the unit, and W is the reaction solid content; w = yield of polymer / total feed quantity * 100%; the total feed quantity comprises the feed quantity of the raw material, the main catalyst and the cocatalyst; the method is low in energy consumption and high in polymerization activity, the obtained polymer is good in fluidity, equipment cannot be blocked, long-term operation of the equipment is facilitated, and the cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of olefin polymerization, and particularly relates to a method for continuous polymerization of ethylene and alpha-olefin. BACKGROUND

[0002] Polyolefin elastomer (POE) is randomly copolymerized by ethylene and 1-butene or 1-octene, and is widely used in application fields such as vehicle plastic modification, photovoltaic adhesive film, shoe material, cable and packaging due to light weight, high transparency, high elasticity, aging resistance and excellent electrical insulation performance. The content of 1-butene or 1-octene in the polyolefin elastomer segment is usually greater than 20 wt%, forming a uniform segment branch distribution, which destroys the crystallinity of the ethylene segment, and the corresponding softening point and melting point of the heat resistance index are reduced while the elasticity, strength and elastic recovery capacity of the rubber are presented. Therefore, the slurry or gas phase process usually cannot meet the production requirements of the polyolefin elastomer, especially when the density of the polyolefin elastomer is lower than 0.88 g / cm 3 , the slurry or gas phase polymerization process is prone to problems such as coking and wall hanging, which affects the long-period stable operation of the production device.

[0003] Solution polymerization is the most important method for producing polyolefin elastomer. Ethylene and 1-butene or 1-octene copolymerization is a strong exothermic reaction type, and effective heat exchange during the polymerization process to neutralize the reaction heat and maintain the reaction temperature parameter constant is the key to ensure the stability of the production process and product index. The process of low-temperature raw material feeding is a common heat exchange method for POE production process, which is to cool ethylene, 1-butene or 1-octene and dispersant raw materials to a certain temperature by using a low-temperature cold source and then continuously feed them into the reactor. The inlet raw materials usually need to be cooled to below 0℃ or even lower temperature, and the heat released in the reactor is exchanged with the low-temperature raw materials to heat up to the target reaction temperature, so as to maintain the stability of the polymerization reaction temperature condition. Under the above heat removal process conditions, the large temperature difference between the raw materials and the reaction system caused by the extremely low feeding temperature makes the temperature field distribution uneven, which affects the catalytic efficiency of the polymerization active center; and the raw materials are cooled to low temperature, which requires high-efficiency refrigeration equipment and high-quality cold source, increasing the energy consumption cost. At the same time, under the abnormal condition of sudden decrease of polymerization activity, the low-temperature raw material feeding adjustment is not timely, which is easy to cause the sudden decrease of the reaction system temperature, and also increases the safety risk of polymer precipitation blocking in the reactor. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is to overcome the defects of insufficient polymerization activity, high polymerization cost and blocking caused by low-temperature feeding in the existing continuous polymerization method of ethylene and alpha-olefin, so as to provide a method for continuous polymerization of ethylene and alpha-olefin.

[0005] To this end, the present application provides the following technical solutions: This invention protects a method for the continuous polymerization of ethylene and α-olefins, wherein the feed temperature of the raw materials is 10-30°C and the polymerization reaction temperature is 120-150°C; The raw materials include ethylene monomers, α-olefin monomers, alkane solvents, and impurity removal agents; or... The raw materials include ethylene monomer, α-olefin monomer, alkane solvent, impurity removal agent and hydrogen; The ratio of the heat of raw material removal to the heat of polymerization reaction is Q, where 50% < Q < 85%. ; Where Xc is the mass percentage of structural units from α-olefin monomers in the polymer, Tr is the polymerization temperature in °C, Ta is the feed temperature in °C, and W is the reaction solids content. W = Polymer yield / Total feed rate × 100%; The total feed amount includes the feed amounts of raw materials, main catalyst, and co-catalyst.

[0006] The formula in this invention includes four variables: Xc, Tr, Ta, and W, forming a multi-parameter linkage control system. By precisely quantifying the dynamic balance between the heat released from the raw materials and the heat released during polymerization, the polymerization reaction is controlled. Tr and Ta are taken only as numerical values, without units, so the resulting Q is dimensionless. Because it is a continuous polymerization reaction, the calculation of W is based on the polymer yield and total feed rate per unit time interval after stable operation (polymerization temperature and raw material feed temperature remain constant; two consecutive temperature measurements with fluctuations <1℃ are considered stable).

[0007] In one optional embodiment, the method includes the following steps: mixing raw materials, adding a main catalyst and a co-catalyst, and carrying out a continuous polymerization reaction to obtain a polymer.

[0008] In this invention, the main catalyst and the co-catalyst are added to the reactor separately and simultaneously.

[0009] In this invention, after the continuous polymerization reaction, the process further includes a step of removing volatile components and a granulation step.

[0010] In one alternative embodiment, the α-olefin monomer includes at least one selected from propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, and 1-decene, and optionally includes 1-butene and / or 1-octene.

[0011] In one optional embodiment, the alkane solvent comprises C6-C... 10 Aliphatic hydrocarbons, C6-C 10At least one of the aromatic solvents, optionally including C8-C4 solvents. 10 Mixed isoalkanes and / or n-hexane; alternatively, IsoparE (C8 content 70-80%, C9 content 20-30%, C6 content 20-30%). 10 The content is <10%) and / or industrial hexane (n-hexane ≥80%).

[0012] In one optional embodiment, the impurity remover includes at least one of methylaluminoxane and triisobutylaluminum, optionally triisobutylaluminum.

[0013] In an optional embodiment, the main catalyst comprises a group IVB-IIB transition metal compound. Optionally, the main catalyst comprises diphenylmethylene(cyclopentadienyl)(9-fluorenyl)zirconia dichloride, di-p-tolyl(cyclopentadienyl)(2,7-di-tert-butyl-fluorenyl)zirconia dichloride, diphenylmethylene(cyclopentadienyl)(octamethyloctahydrobenzofluorenyl)zirconia dichloride, diphenylmethylene(3-tert-butyl-2-methylcyclopentadienyl)(fluorenyl)zirconia dichloride, bis(tetramethylcyclopentadienyl)hafnium dichloride, rac-ethylene-bis(indenyl)hafnium dichloride, dimethylsilyl(tert-butylamino)(tetramethylcyclopentadienyl)dimethyltitanium, dimethylsilyl(tert-butylamino)(4-pyrrolo-indenyl)dimethyltitanium, (η 5 At least one of (indenyl)dimethylsilyl(tert-butyl)amido)titanium dichloride, dimethylsilyl(tert-butylamino)(3,6-di-tert-butyl-fluorenyl)dimethyltitanium, and [(7-methyl-tetrahydroquinoline-8-yl)tetramethylcyclopentadienyl-N]dimethyltitanium; more preferably, it includes diphenylmethylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2,7-di-tert-butyl-fluorenyl)zirconium dichloride, and (η 5 -(indenyl)dimethylsilyl(tert-butyl)amido)titanium dichloride.

[0014] In one optional embodiment, the cocatalyst comprises at least one of tris(pentafluorophenyl)boron, triphenylcarbium tetra(pentafluorophenyl)boron, and N,N-dimethylaniline tetra(pentafluorophenyl)boron. Optionally, the cocatalyst is N,N-dimethylaniline tetra(pentafluorophenyl)boron.

[0015] In one optional embodiment, the mass ratio of the ethylene monomer to the α-olefin monomer is (40-85):100.

[0016] In one optional embodiment, the mass ratio of the ethylene monomer to hydrogen is 1:(0-9×10⁻⁶). -4 ).

[0017] In one optional embodiment, the amount of alkane solvent used is 55%-75% based on the mass of the raw material.

[0018] In one alternative embodiment, the amount of impurity remover used is 8-20 ppm based on the mass of the raw material.

[0019] In one optional embodiment, the amount of the main catalyst is 0.05-0.15 ppm based on the mass of the raw material.

[0020] In one alternative embodiment, the amount of co-catalyst used is 0.1-0.4 ppm based on the mass of the raw material.

[0021] In this invention, the polymerization reaction pressure is 3-5 MPaG, where MPaG is gauge pressure, and the reaction time in the reactor is 5-10 min.

[0022] The technical solution of this invention has the following advantages: This invention provides a method for the continuous polymerization of ethylene and α-olefins, wherein the feed temperature of the raw materials is 10-30°C; the polymerization reaction temperature is 120-150°C; the raw materials include ethylene monomer, α-olefin monomer, alkane solvent, and a purification agent; or, the raw materials include ethylene monomer, α-olefin monomer, alkane solvent, a purification agent, and hydrogen; the ratio of the heat of heat removal from the raw materials to the heat of heat exchange in the polymerization reaction is Q, where 50% < Q < 85%. Where Xc is the mass percentage of structural units from α-olefin monomers in the polymer, Tr is the polymerization temperature in °C, Ta is the feed temperature in °C, and W is the reaction solids content; W = polymer yield / total feed amount × 100%; wherein, the total feed amount includes the feed amounts of raw materials, main catalyst, and co-catalyst; the formula in the method of this invention includes four variables, Xc, Tr, Ta, and W, forming a multi-parameter linkage control system, controlling the Q value within 50% < Q < 85%, realizing the control of the polymerization reaction, reducing the difference between the feed temperature and the polymerization temperature, improving the uniformity of temperature distribution, and effectively improving the polymerization activity; the feed temperature of the raw materials in this invention is 10-30 °C, which greatly reduces energy costs compared to the prior art of cooling the raw materials to below 0 °C or even lower temperatures; and the obtained polymer has good fluidity, will not clog the equipment, is conducive to the long-term operation of the equipment, and reduces operating costs. Detailed Implementation

[0023] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms “comprising” and “having” and any variations thereof in the text of this invention are intended to cover non-exclusive inclusion.

[0025] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] The "range" disclosed in this invention is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. This range can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. In this invention, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers from a to b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed herein; "0-5" is merely a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥ 2, it is equivalent to disclosing that the parameter can be, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0027] In the description of the embodiments of the present invention, the term "and / or" is merely a description of the relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0028] In the description of the embodiments of the present invention, the term "at least one" refers to one or more (including two).

[0029] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0030] Table 1. Raw material sources and specifications

[0031] Example 1 This embodiment provides a method for the continuous polymerization of ethylene and α-olefins, including the following steps: IsoparE (1000 kg / h), 1-butene (310 kg / h), ethylene monomer (143 kg / h), and triisobutylaluminum (20 g / h) were mixed under a pressure of 4.2 MPaG, and the temperature was adjusted to 10°C. The mixture was then fed into a 250 L stirred reactor preheated to 120°C. (η) 5 (Indene)dimethylsilyl(tert-butyl)amido)titanium dichloride and N,N-dimethylanilinetetra(pentafluorophenyl)boron were added separately to the reactor at feed rates of 101 mg / h and 400 mg / h, respectively. The polymerization reaction was carried out at 120 °C. After the reaction was carried out in the reactor for 7 min, the polymer solution was discharged from the reactor outlet and heated to 260 °C to remove volatile components. The separated product was granulated by an extrusion pelletizing system to obtain granular polymer.

[0032] Example 2 This embodiment provides a method for the continuous polymerization of ethylene and α-olefins, including the following steps: IsoparE (682 kg / h), 1-butene (279 kg / h), ethylene monomer (112 kg / h), and triisobutylaluminum (11 g / h) were mixed at a pressure of 4.2 MPaG, and the temperature was adjusted to 20°C before being fed into a 250 L stirred reactor preheated to 120°C; (η 5 (Indene)dimethylsilyl(tert-butyl)amido)titanium dichloride and N,N-dimethylaniline tetra(pentafluorophenyl)boron were added separately to the reactor at feed rates of 61 mg / h and 200 mg / h, respectively. The polymerization reaction was carried out at 120 °C. After the reaction was carried out in the reactor for 10 min, the polymer solution was discharged from the reactor outlet and heated to 260 °C to remove volatile components. The separated product was granulated by an extrusion pelletizing system to obtain granular polymer.

[0033] Example 3 This embodiment provides a method for the continuous polymerization of ethylene and α-olefins, including the following steps: Industrial hexane (845 kg / h), 1-butene (286 kg / h), ethylene monomer (164 kg / h), hydrogen (2 g / h), and triisobutylaluminum (16 g / h) were mixed at a pressure of 4.2 MPaG, and the temperature was adjusted to 30°C. The mixture was then fed into a 250 L stirred reactor preheated to 120°C. (η) 5 -(indenyl)dimethylsilyl(tert-butyl)amido)titanium dichloride and N,N-dimethylaniline tetra(pentafluorophenyl)boron were added separately to the reactor at feed rates of 71 mg / h and 250 mg / h, respectively. The polymerization reaction was carried out at 120 °C. After the reaction was carried out in the reactor for 8 min, the polymer solution was discharged from the reactor outlet and heated to 260 °C to remove volatile components. The separated product was granulated by an extrusion pelletizing system to obtain granular polymer.

[0034] Example 4 This embodiment provides a method for the continuous polymerization of ethylene and α-olefins, including the following steps: IsoparE (702 kg / h), 1-butene (274 kg / h), ethylene monomer (161 kg / h), hydrogen (2 g / h), and triisobutylaluminum (16 g / h) were mixed at a pressure of 4.2 MPaG, and the temperature was adjusted to 10°C before being fed into a 250 L stirred reactor preheated to 140°C; (η 5 (Indene)dimethylsilyl(tert-butyl)amido)titanium dichloride and N,N-dimethylanilinetetra(pentafluorophenyl)boron were added separately to the reactor at feed rates of 71 mg / h and 250 mg / h, respectively. The polymerization reaction was carried out at 140 °C. After the reaction was carried out in the reactor for 9 min, the polymer solution was discharged from the reactor outlet and heated to 260 °C to remove volatile components. The separated product was granulated by an extrusion pelletizing system to obtain granular polymer.

[0035] Example 5 This embodiment provides a method for the continuous polymerization of ethylene and α-olefins, including the following steps: IsoparE (706 kg / h), 1-butene (270 kg / h), ethylene monomer (198 kg / h), hydrogen (160 g / h), and triisobutylaluminum (16 g / h) were mixed at a pressure of 4.2 MPaG, and the temperature was adjusted to 20°C. The mixture was then fed into a 250 L stirred reactor preheated to 140°C. (η) 5-(indenyl)dimethylsilyl(tert-butyl)amido)titanium dichloride and N,N-dimethylaniline tetra(pentafluorophenyl)boron were added separately to the reactor at feed rates of 89 mg / h and 290 mg / h, respectively. The polymerization reaction was carried out at 140 °C. After the reaction was carried out in the reactor for 9 min, the polymer solution was discharged from the reactor outlet and heated to 260 °C to remove volatile components. The separated product was granulated by an extrusion pelletizing system to obtain granular polymer.

[0036] Example 6 This embodiment provides a method for the continuous polymerization of ethylene and α-olefins, including the following steps: IsoparE (779 kg / h), 1-butene (226 kg / h), ethylene monomer (169 kg / h), hydrogen (40 g / h), and triisobutylaluminum (21 g / h) were mixed at a pressure of 4.2 MPaG, and the temperature was adjusted to 30°C. The mixture was then fed into a 250 L stirred reactor preheated to 140°C. (η) 5 -(indenyl)dimethylsilyl(tert-butyl)amido)titanium dichloride and N,N-dimethylaniline tetra(pentafluorophenyl)boron were added separately to the reactor at feed rates of 102 mg / h and 380 mg / h, respectively. The polymerization reaction was carried out at 140 °C. After the reaction was carried out in the reactor for 9 min, the polymer solution was discharged from the reactor outlet and heated to 260 °C to remove volatile components. The separated product was granulated by an extrusion pelletizing system to obtain granular polymer.

[0037] Example 7 This embodiment provides a method for the continuous polymerization of ethylene and α-olefins, including the following steps: Under a pressure of 4.2 MPaG, IsoparE (685 kg / h), 1-butene (298 kg / h), ethylene monomer (178 kg / h), hydrogen (2 g / h), and triisobutylaluminum (15 g / h) were mixed and the temperature was adjusted to 10°C. The mixture was then fed into a 250 L stirred reactor preheated to 150°C. Diphenylmethylene (cyclopentadienyl)(9-fluorenyl)zirconium dichloride and N,N-dimethylaniline tetra(pentafluorophenyl)boron were added to the reactor separately at feed rates of 112 mg / h and 250 mg / h, respectively. The polymerization reaction was carried out at 150°C. After the reaction was carried out in the reactor for 9 minutes, the polymer solution was discharged from the reactor outlet. After being heated to 260°C by a heater, volatile components were removed. The separated product was granulated by an extrusion pelletizing system to obtain granular polymer.

[0038] Example 8 This embodiment provides a method for the continuous polymerization of ethylene and α-olefins, including the following steps: Under a pressure of 4.2 MPaG, IsoparE (685 kg / h), 1-butene (212 kg / h), ethylene monomer (165 kg / h), hydrogen (2 g / h), and triisobutylaluminum (13 g / h) were mixed and the temperature was adjusted to 20°C. The mixture was then fed into a 250 L stirred reactor preheated to 150°C. Diphenylmethylene (cyclopentadienyl)(9-fluorenyl)zirconium dichloride and N,N-dimethylaniline tetra(pentafluorophenyl)boron were added to the reactor separately at feed rates of 101 mg / h and 250 mg / h, respectively. The polymerization reaction was carried out at 150°C. After the reaction was carried out in the reactor for 10 min, the polymer solution was discharged from the reactor outlet. After being heated to 260°C by a heater, volatile components were removed. The separated product was granulated by an extrusion pelletizing system to obtain granular polymer.

[0039] Example 9 This embodiment provides a method for the continuous polymerization of ethylene and α-olefins, including the following steps: Under a pressure of 4.2 MPaG, IsoparE (700 kg / h), 1-butene (213 kg / h), ethylene monomer (180 kg / h), hydrogen (70 g / h), and triisobutylaluminum (13 g / h) were mixed and the temperature was adjusted to 30°C. The mixture was then fed into a 250 L stirred reactor preheated to 150°C. Diphenylmethylene (cyclopentadienyl)(9-fluorenyl)zirconium dichloride and N,N-dimethylaniline tetra(pentafluorophenyl)boron were added to the reactor separately at feed rates of 109 mg / h and 250 mg / h, respectively. The polymerization reaction was carried out at 150°C. After the reaction was carried out in the reactor for 10 min, the polymer solution was discharged from the reactor outlet. After being heated to 260°C by a heater, volatile components were removed. The separated product was granulated by an extrusion pelletizing system to obtain granular polymer.

[0040] Example 10 This embodiment provides a method for the continuous polymerization of ethylene and α-olefins, including the following steps: IsoparE (698 kg / h), 1-octene (224 kg / h), ethylene monomer (95 kg / h), and triisobutylaluminum (10 g / h) were mixed under a pressure of 4.2 MPaG, and the temperature was adjusted to 10 °C. The mixture was then fed into a 250 L stirred reactor preheated to 135 °C. Diphenylmethylene (cyclopentadienyl) (2,7-di-tert-butyl-fluorenyl)zirconium dichloride and N,N-dimethylaniline tetra(pentafluorophenyl)boron were added to the reactor separately at feed rates of 62 mg / h and 200 mg / h, respectively. The polymerization reaction was carried out at 135 °C. After the reaction was carried out in the reactor for 10 min, the polymer solution was discharged from the reactor outlet. After being heated to 260 °C by a heater, volatile components were removed. The separated product was granulated by an extrusion pelletizing system to obtain granular polymer.

[0041] Example 11 This embodiment provides a method for the continuous polymerization of ethylene and α-olefins, including the following steps: IsoparE (756 kg / h), 1-octene (276 kg / h), ethylene monomer (112 kg / h), and triisobutylaluminum (10 g / h) were mixed under a pressure of 4.2 MPaG, and the temperature was adjusted to 20°C. The mixture was then fed into a 250 L stirred reactor preheated to 135°C. Diphenylmethylene (cyclopentadienyl)(2,7-di-tert-butyl-fluorenyl)zirconium dichloride and N,N-dimethylaniline tetra(pentafluorophenyl)boron were added to the reactor separately at feed rates of 60 mg / h and 200 mg / h, respectively. The polymerization reaction was carried out at 135°C. After the reaction was carried out in the reactor for 9 min, the polymer solution was discharged from the reactor outlet. After being heated to 260°C by a heater, volatile components were removed. The separated product was granulated by an extrusion pelletizing system to obtain granular polymer.

[0042] Example 12 This embodiment provides a method for the continuous polymerization of ethylene and α-olefins, including the following steps: IsoparE (736 kg / h), 1-octene (267 kg / h), ethylene monomer (136 kg / h), and triisobutylaluminum (10 g / h) were mixed under a pressure of 4.2 MPaG, and the temperature was adjusted to 30°C. The mixture was then fed into a 250 L stirred reactor preheated to 135°C. Diphenylmethylene (cyclopentadienyl)(2,7-di-tert-butyl-fluorenyl)zirconium dichloride and N,N-dimethylaniline tetra(pentafluorophenyl)boron were added to the reactor separately at feed rates of 65 mg / h and 200 mg / h, respectively. The polymerization reaction was carried out at 135°C. After the reaction was carried out in the reactor for 9 min, the polymer solution was discharged from the reactor outlet. After being heated to 260°C by a heater, volatile components were removed. The separated product was granulated by an extrusion pelletizing system to obtain granular polymer.

[0043] Comparative Example 1 This comparative example provides a method for the continuous polymerization of ethylene and α-olefins, following the procedure of Example 4, except that the feed rate of IsoparE is 1023 kg / h, the feed rate of triisobutylaluminum is 39 g / h, and the temperature is adjusted to 5°C. (η) 5 The feed rate for (indene)dimethylsilyl(tert-butyl)amide)titanium dichloride is 460 mg / h, and the feed rate for N,N-dimethylaniline tetra(pentafluorophenyl)boron is 1200 mg / h.

[0044] Comparative Example 2 This comparative example provides a method for the continuous polymerization of ethylene and α-olefins, following the procedure of Example 6, except that the feed rate of IsoparE is 655 kg / h, the feed rate of triisobutylaluminum is 43 g / h, and the temperature is adjusted to 35°C. (η) 5 The feed rate for (indene)dimethylsilyl(tert-butyl)amide-1,4-dichlorotitanium chloride is 230 mg / h, and the feed rate for N,N-dimethylaniline tetra(pentafluorophenyl)boron is 700 mg / h.

[0045] Comparative Example 3 This comparative example provides a method for the continuous polymerization of ethylene and α-olefins, following the method of Example 8, except that the feed rate of triisobutylaluminum is 21 g / h, the feed rate of diphenylmethylene (cyclopentadienyl)(9-fluorenyl)zirconium dichloride is 340 mg / h, the feed rate of N,N-dimethylaniline tetra(pentafluorophenyl)boron is 450 mg / h, the preheating temperature of the reactor is 115°C, and the polymerization temperature is 115°C.

[0046] Comparative Example 4 This comparative example provides a method for the continuous polymerization of ethylene and α-olefins, following the method of Example 10, except that the temperature is adjusted to 5°C, the feed rate of diphenylmethylene (cyclopentadienyl) (2,7-di-tert-butyl-fluorenyl)zirconium dichloride is 230 mg / h, and the feed rate of N,N-dimethylaniline tetra(pentafluorophenyl)boron is 400 mg / h.

[0047] Comparative Example 5 This comparative example provides a method for the continuous polymerization of ethylene and α-olefins, following the method of Example 11, except that the IsoparE feed rate is 356 kg / h, the temperature is adjusted to 35°C, and the feed rate of diphenylmethylene (cyclopentadienyl) (2,7-di-tert-butyl-fluorenyl)zirconium dichloride is 130 mg / h.

[0048] Comparative Example 6 This comparative example provides a method for the continuous polymerization of ethylene and α-olefins, following the method of Example 11, except that the feed rate of IsoparE is 908 kg / h, the feed rate of diphenylmethylene (cyclopentadienyl) (2,7-di-tert-butylfluorenyl)zirconium dichloride is 150 mg / h, the preheating temperature of the reactor is 155°C, and the polymerization temperature is 155°C.

[0049] Comparative Example 7 This comparative example provides a method for the continuous polymerization of ethylene and α-olefins, following the method of Example 1, except that the temperature is adjusted to -10°C.

[0050] Comparative Example 8 This comparative example provides a method for the continuous polymerization of ethylene and α-olefins, following the method of Example 1, except that the temperature is adjusted to 50°C.

[0051] Test case The method for determining the mass percentage (Xc) of structural units derived from α-olefin monomers in polymers was as follows: High-temperature gel permeation chromatography-infrared spectroscopy (GPC-IR) was used with 1,2,4-trichlorobenzene as the mobile phase and polystyrene as the standard. The polymer sample was measured at 150℃. The standard concentration was 0.1 mg / mL, the solvent flow rate was 1.0 mL / min, and the standard parameters were K=59.1, α=0.69. The parameters for the sample were K=14.1, α=0.70. The continuous polymerization reaction of ethylene and α-olefins was carried out after the reaction solids were stabilized. The reactor temperature and feed temperature were measured twice consecutively. The temperature fluctuation was considered to be less than 1°C after the reaction was stabilized. For more accurate measurement, the time from the first hour to the second hour after the stable operation was taken as the time. The polymer yield and total feed amount were calculated and substituted into the formula = polymer yield / total feed amount × 100% (the time period from the first hour to the second hour after the stable operation). ; Table 2. Parameters and Results for Q-Value Calculation

[0052] Polymer yield is the mass of polymer produced per unit time.

[0053] The weight-average molecular weight and molecular weight distribution (PDI) of the polymer were determined using high-temperature gel permeation chromatography-infrared spectroscopy (GPC-IR) with 1,2,4-trichlorobenzene as the mobile phase and polystyrene as the standard. The polymer samples were measured at 150 °C with a standard concentration of 0.1 mg / mL and a solvent flow rate of 1.0 mL / min. The standard parameters were K=59.1 and α=0.69, while the parameters for the test samples were K=14.1 and α=0.70.

[0054] The formula for calculating polymerization activity is: mass of polymer obtained in 1 hour / amount of main catalyst used. The electrical energy consumed by the refrigeration unit (for cooling raw materials and reaction equipment) and the electric heating system (for heating raw materials and reaction liquid) when producing 1 ton of polymer is calculated. Test method for reactor blockage degree: The polymer is cast into a 0.2 mm thick film at 120℃. Six films with an area of ​​10 cm × 10 cm are randomly cut. The number of gel points on each film is counted manually. This is repeated 3 times, and the average value is magnified 100 times. The density of gel points per m³ is calculated. 2 The number of gel points in the membrane indicates a high degree of polymer blockage on the reactor walls. Specific test parameters are shown in Table 3; Table 3. Relevant Test Parameters for Polymers and Polymerization Systems

[0055] As can be seen from the data in Table 3, compared with Example 1, Comparative Example 7 requires more energy to lower the temperature to -10°C, and Comparative Example 8 requires more energy to raise the temperature to 50°C. Furthermore, in Comparative Example 7, the polymerization activity is greatly reduced, and the polymer obtained has the highest gel point.

[0056] This invention reduces the temperature difference between the raw material feed temperature and the polymerization temperature, improves the uniformity of temperature distribution, and effectively enhances polymerization activity. The raw material feed temperature is 10-30℃, which greatly reduces energy costs compared to existing technologies that cool the raw material to below 0℃ or even lower temperatures. Furthermore, the resulting polymer has good flowability, does not clog equipment, and is conducive to long-term equipment operation, thus reducing operating costs.

[0057] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for the continuous polymerization of ethylene and α-olefins, characterized in that, The feed temperature of the raw materials in the method is 10-30℃; the polymerization reaction temperature is 120-150℃. The raw materials include ethylene monomers, α-olefin monomers, alkane solvents, and impurity removal agents; or... The raw materials include ethylene monomer, α-olefin monomer, alkane solvent, impurity removal agent and hydrogen; The ratio of the heat of raw material removal to the heat of polymerization reaction is Q, where 50% < Q < 85%. ； Where Xc is the mass percentage of structural units from α-olefin monomers in the polymer, Tr is the polymerization temperature in °C, Ta is the feed temperature in °C, and W is the reaction solids content. W = Polymer yield / Total feed rate × 100%; The total feed amount includes the feed amounts of raw materials, main catalyst, and co-catalyst.

2. The method according to claim 1, characterized in that, The method includes the following steps: mixing raw materials, adding a main catalyst and a co-catalyst, and carrying out a continuous polymerization reaction to obtain a polymer.

3. The method according to claim 2, characterized in that, The continuous polymerization reaction also includes a step of removing volatile components and a granulation step.

4. The method according to claim 1, characterized in that, The α-olefin monomer includes at least one selected from propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, and 1-decene.

5. The method according to claim 4, characterized in that, The α-olefin monomers include 1-butene and / or 1-octene.

6. The method according to claim 1, characterized in that, The alkane solvent includes C6-C. 10 Aliphatic hydrocarbons, C6-C 10 At least one of the aromatic solvents; And / or, the impurity remover includes at least one of methylaluminoxane and triisobutylaluminum.

7. The method according to claim 1, characterized in that, The main catalyst comprises group IVB-IIB transition metal compounds; And / or, the cocatalyst comprises at least one of tris(pentafluorophenyl)boron, triphenylcarbium tetra(pentafluorophenyl)boron, and N,N-dimethylaniline tetra(pentafluorophenyl)boron.

8. The method according to claim 7, characterized in that, The main catalyst includes diphenylmethylene(cyclopentadienyl)(2,7-di-tert-butyl-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride, di-p-tolyl(cyclopentadienyl)(2,7-di-tert-butyl-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(octamethyloctahydrobenzofluorenyl)zirconium dichloride, diphenylmethylene(3-tert-butyl-2-methylcyclopentadienyl)(fluorenyl)zirconium dichloride, bis(tetramethylcyclopentadienyl)hafnium dichloride, rac-ethylene-bis(indenyl)hafnium dichloride, dimethylsilyl(tert-butylamino)(tetramethylcyclopentadienyl)dimethyltitanium, dimethylsilyl(tert-butylamino)(4-pyrrole-indenyl)dimethyltitanium, (η 5 At least one of the following: (indenyl)dimethylsilyl(tert-butyl)amido)titanium dichloride, dimethylsilyl(tert-butylamino)(3,6-di-tert-butyl-fluorenyl)dimethyltitanium, and [(7-methyl-tetrahydroquinoline-8-yl)tetramethylcyclopentadienyl-N]dimethyltitanium; And / or, the cocatalyst is N,N-dimethylaniline tetra(pentafluorophenyl)boron.

9. The method according to claim 1, characterized in that, The mass ratio of the ethylene monomer to the α-olefin monomer is (40-85):100; And / or, the mass ratio of the ethylene monomer to hydrogen is 1:(0-9×10⁻⁶). -4 ); And / or, based on the mass of the raw material, the amount of alkane solvent used is 55%-75%; And / or, based on the mass of the raw material, the amount of impurity remover is 8-20 ppm.

10. The method according to claim 1, characterized in that, The amount of the main catalyst used is 0.05-0.15 ppm based on the mass of the raw material; And / or, based on the mass of the raw material, the amount of co-catalyst is 0.1-0.4 ppm.

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