CN111363222A - Polymer composition, preparation method, application and synthesis device thereof - Google Patents
Polymer composition, preparation method, application and synthesis device thereof Download PDFInfo
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- 239000000203 mixture Substances 0.000 title claims abstract description 163
- 229920000642 polymer Polymers 0.000 title claims abstract description 159
- 238000002360 preparation method Methods 0.000 title claims abstract description 8
- 230000015572 biosynthetic process Effects 0.000 title abstract description 3
- 238000003786 synthesis reaction Methods 0.000 title abstract description 3
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims abstract description 72
- 239000005977 Ethylene Substances 0.000 claims abstract description 72
- 229920001519 homopolymer Polymers 0.000 claims abstract description 29
- 239000004711 α-olefin Substances 0.000 claims abstract description 28
- 229920001577 copolymer Polymers 0.000 claims abstract description 19
- 239000000498 cooling water Substances 0.000 claims description 98
- 238000006116 polymerization reaction Methods 0.000 claims description 94
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims description 51
- 238000000034 method Methods 0.000 claims description 38
- 238000001816 cooling Methods 0.000 claims description 29
- 239000001257 hydrogen Substances 0.000 claims description 26
- 229910052739 hydrogen Inorganic materials 0.000 claims description 26
- 239000000463 material Substances 0.000 claims description 21
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 16
- 239000000155 melt Substances 0.000 claims description 15
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 claims description 14
- NNPPMTNAJDCUHE-UHFFFAOYSA-N isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 claims description 14
- 239000011954 Ziegler–Natta catalyst Substances 0.000 claims description 12
- 239000003085 diluting agent Substances 0.000 claims description 12
- 150000002431 hydrogen Chemical class 0.000 claims description 10
- 239000002685 polymerization catalyst Substances 0.000 claims description 9
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 claims description 8
- VOITXYVAKOUIBA-UHFFFAOYSA-N triethylaluminium Chemical group CC[Al](CC)CC VOITXYVAKOUIBA-UHFFFAOYSA-N 0.000 claims description 8
- 239000003054 catalyst Substances 0.000 claims description 7
- 239000003426 co-catalyst Substances 0.000 claims description 7
- 239000001282 iso-butane Substances 0.000 claims description 7
- LIKMAJRDDDTEIG-UHFFFAOYSA-N 1-hexene Chemical compound CCCCC=C LIKMAJRDDDTEIG-UHFFFAOYSA-N 0.000 claims description 6
- 238000000926 separation method Methods 0.000 claims description 5
- KWKAKUADMBZCLK-UHFFFAOYSA-N 1-octene Chemical compound CCCCCCC=C KWKAKUADMBZCLK-UHFFFAOYSA-N 0.000 claims description 4
- RGSFGYAAUTVSQA-UHFFFAOYSA-N Cyclopentane Chemical compound C1CCCC1 RGSFGYAAUTVSQA-UHFFFAOYSA-N 0.000 claims description 4
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 claims description 4
- OFBQJSOFQDEBGM-UHFFFAOYSA-N Pentane Chemical compound CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 claims description 4
- 238000007599 discharging Methods 0.000 claims description 4
- QWTDNUCVQCZILF-UHFFFAOYSA-N isopentane Chemical compound CCC(C)C QWTDNUCVQCZILF-UHFFFAOYSA-N 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 239000012968 metallocene catalyst Substances 0.000 claims description 4
- 239000001294 propane Substances 0.000 claims description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 2
- 229910052804 chromium Inorganic materials 0.000 claims description 2
- 239000011651 chromium Substances 0.000 claims description 2
- AFABGHUZZDYHJO-UHFFFAOYSA-N dimethyl butane Natural products CCCC(C)C AFABGHUZZDYHJO-UHFFFAOYSA-N 0.000 claims description 2
- DMEGYFMYUHOHGS-UHFFFAOYSA-N heptamethylene Natural products C1CCCCCC1 DMEGYFMYUHOHGS-UHFFFAOYSA-N 0.000 claims description 2
- 229910052749 magnesium Inorganic materials 0.000 claims description 2
- 239000011777 magnesium Substances 0.000 claims description 2
- CPOFMOWDMVWCLF-UHFFFAOYSA-N methyl(oxo)alumane Chemical group C[Al]=O CPOFMOWDMVWCLF-UHFFFAOYSA-N 0.000 claims description 2
- TVMXDCGIABBOFY-UHFFFAOYSA-N n-Octanol Natural products CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 claims description 2
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 claims description 2
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 239000010936 titanium Substances 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims 1
- 239000004698 Polyethylene Substances 0.000 description 30
- 229920000573 polyethylene Polymers 0.000 description 30
- -1 Polyethylene Polymers 0.000 description 29
- 238000009826 distribution Methods 0.000 description 28
- 230000002902 bimodal effect Effects 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 7
- 238000012545 processing Methods 0.000 description 5
- 238000005227 gel permeation chromatography Methods 0.000 description 4
- 238000011065 in-situ storage Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 239000004705 High-molecular-weight polyethylene Substances 0.000 description 2
- 239000004699 Ultra-high molecular weight polyethylene Substances 0.000 description 2
- 239000004708 Very-low-density polyethylene Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229920001903 high density polyethylene Polymers 0.000 description 2
- 229920006158 high molecular weight polymer Polymers 0.000 description 2
- 239000004700 high-density polyethylene Substances 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 229920000092 linear low density polyethylene Polymers 0.000 description 2
- 239000004707 linear low-density polyethylene Substances 0.000 description 2
- 229920001684 low density polyethylene Polymers 0.000 description 2
- 239000004702 low-density polyethylene Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 230000000379 polymerizing effect Effects 0.000 description 2
- 150000003384 small molecules Chemical class 0.000 description 2
- 229920000785 ultra high molecular weight polyethylene Polymers 0.000 description 2
- 229920001862 ultra low molecular weight polyethylene Polymers 0.000 description 2
- 229920001866 very low density polyethylene Polymers 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000000071 blow moulding Methods 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007765 extrusion coating Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000000415 inactivating effect Effects 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 239000013081 microcrystal Substances 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 238000005191 phase separation Methods 0.000 description 1
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- 238000007665 sagging Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/04—Homopolymers or copolymers of ethene
- C08L23/06—Polyethene
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
- B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
- B01J8/06—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds in tube reactors; the solid particles being arranged in tubes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
- B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
- B01J8/06—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds in tube reactors; the solid particles being arranged in tubes
- B01J8/067—Heating or cooling the reactor
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F110/00—Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- C08F110/02—Ethene
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- C08F210/16—Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/04—Homopolymers or copolymers of ethene
- C08L23/08—Copolymers of ethene
- C08L23/0807—Copolymers of ethene with unsaturated hydrocarbons only containing more than three carbon atoms
- C08L23/0815—Copolymers of ethene with aliphatic 1-olefins
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2203/00—Applications
- C08L2203/16—Applications used for films
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2203/00—Applications
- C08L2203/18—Applications used for pipes
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
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- C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
- C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
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- C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend
Abstract
The invention provides a polymer composition, a preparation method, application and a synthesis device thereof, wherein the polymer composition comprises a first polymer, a second polymer and a third polymer, wherein the first polymer is a first ethylene homopolymer, the second polymer is a second ethylene homopolymer or a first copolymer formed by copolymerizing ethylene and a first α -olefin, and the third polymer is a third ethylene homopolymer or a second copolymer formed by copolymerizing ethylene and a second α -olefin, the weight average molecular weight of the first polymer is more than 250 ten thousand, the content of the first polymer is more than 5 percent based on 100 percent of the total mass of the polymer composition.
Description
Technical Field
The invention provides a polymer composition and a preparation method thereof, in particular to a composition of ethylene homopolymer and other ethylene homopolymer or copolymer formed by polymerizing ethylene and α -olefin, and a method and a device for synthesizing the same.
Background
Polyethylene is used in a very wide range of applications as plastics, such as films, pipes, blow moulding, stretched tapes and fibres, injection moulding, caps and covers, extrusion coating and the like. For different applications, specific properties are required, which relate to the macroscopic properties of polyethylene. Polyethylene can be classified into several types according to macroscopic properties, such as, but not limited to, LDPE (low density polyethylene), LLDPE (linear low density polyethylene), HDPE (high density polyethylene), VLDPE (very low density polyethylene), and ULDPE (ultra low density polyethylene), or High Molecular Weight Polyethylene (HMWPE), Medium Molecular Weight Polyethylene (MMWPE), and Low Molecular Weight Polyethylene (LMWPE). Polyethylene having a molecular weight in excess of 250 million is known as ultra high molecular weight polyethylene. Each type of polyethylene has different properties and characteristics. The molecular weight of polyethylene is expressed in different ways, with weight average molecular weight being the most common method. Meanwhile, because direct measurement of molecular weight is complicated, people in practical application express the molecular weight by measuring the melt flow rate. Melt flow rate refers to the weight of a plastic at a given temperature and constant load, expressed as grams/10 minutes, that the melt flows through a standard capillary over a certain period of time. Generally, the smaller the melt flow rate, the larger the average molecular weight. In addition to the determination of the average molecular weight by means of melt flow rate, the proportion of molecules of different sizes is determined by means of gel chromatography (GPC), which gives a molecular weight distribution curve (the abscissa is the molecular weight and the ordinate is the mass percentage of the various molecules present) or a distribution curve of the degree of polymerization (the abscissa is the degree of polymerization and the ordinate is the probability of the degree of polymerization distribution), which gives better insight into the microstructure of polyethylene.
The processability of polyethylene can be evaluated by measuring properties such as melt flow rate (flowability), spiral flow, rheology, melt strength, etc., and the mechanical properties by measuring tensile properties, toughness, creep resistance, etc. To impart better mechanical properties to polyethylene, it is generally necessary to increase the molecular weight of the polyethylene, but to balance its flowability during processing, it is also necessary to increase the content of small molecules. In most cases, the size of the molecules has an adverse effect on processability and mechanical properties, and so-called "bimodal" or "multimodal" polyethylenes have been designed. The polyethylene with bimodal structure means that two peaks appear on a distribution curve of the polymerization degree of the polyethylene. Since for ethylene polymerization catalysts of the same type can only produce "unimodal" polyethylene in one reactor (same reaction conditions), such bimodal polyethylene can usually be produced in two to three polymerization reactors operated under different reaction conditions in series, for example, the methods for producing bimodal polyethylene by a combined process of olefin polymerization in at least two reactors in series as mentioned in CN101790544A, CN101035817B and CN1903896A, CN105814100A and CN105793291A disclose methods for producing multimodal polyethylene by at least three combined reactors, and patents WO 0170872 a1, WO 07028552 a1, WO 06018245 a1, WO 06053709 a1, CN101400933A and CN105814100A describe the use of bimodal or multimodal polyethylene in pipes, membranes and fibers, respectively.
The design of a bimodal structure is an effective method for improving the performance of the product, but the product can have good product performance instead of the bimodal structure, wherein a key requirement is that a molecular chain with high molecular weight needs to have a certain number of branched chains, the molecular chain is called a frenum molecule, and the frenum molecule are connected with two or more microcrystals to improve the overall mechanical property of the product. The direct preparation of polyethylene having a bimodal structure by means of polymerization, so-called "in-situ" polymerization, to a high degree of micromixing is necessary, since it has been found that remelting two polyethylenes of different molecular weights after the reaction, e.g. during post-processing, i.e. the properties of the product obtained by the post-compounding process do not meet the requirements for the required micromixing uniformity, and the properties of the product are also reduced. Thus, the current "bimodal" technology is to obtain two components, namely small molecules and high molecules with branched chains through "in situ" polymerization, so as to realize the simultaneous improvement of mechanical properties and fluidity.
Methods for producing "trimodal" or higher products are easily envisioned, and methods for producing "bimodal" products, i.e., adjusting the amount of molecular weight regulator (hydrogen) in multiple reactors, can be simply borrowed. Some "trimodal" product production technologies, such as CN101128521A and CN1717448A, have been previously disclosed, however these technologies do not address the issue of processing requiring higher "melt strength". It is well known that polyethylene must undergo at least one heating and reach the molten state during processing, and therefore the melt strength is an important property of the processability of polyethylene products, a low melt strength causing surface cracking of the melt or undesired deformation (sagging) under the influence of gravity, thus affecting the processing speed or the quality of the product (for example, non-uniformity of the geometry). Improving melt strength has been a technical problem that needs to be addressed in the industry, and it has also been found that very long molecular chains (e.g., molecular weights of up to 300 million or more) are helpful in improving melt strength. CN101400933A discloses a method for producing "multimodal" products containing more than 15% of "ultra high molecular weight copolymer structure", but this technique does not provide a method for producing "ultra high molecular weight polymer" multimodal products with reactor settings, reaction temperatures, etc., as described in its examples, a catalyst with "extremely high response to hydrogen and high activity" is required to make it possible to produce "ultra high molecular weight polymer" multimodal products without a reasonable design of reactor and reaction conditions.
Therefore, there is an urgent need in the art for a process, and particularly a polymerization technique, for producing multimodal polyethylene, which can improve mechanical properties while maintaining good flowability and melt strength, and a technique for polymerizing ultra-long molecular chains "in situ" into "multimodal" polyethylene is highly desirable.
Disclosure of Invention
The invention provides a polymer composition, which comprises a first polymer, a second polymer and a third polymer, wherein the first polymer is a first ethylene homopolymer, the second polymer is a second ethylene homopolymer or a first copolymer formed by copolymerizing ethylene and a first α -olefin, the third polymer is a third ethylene homopolymer or a second copolymer formed by copolymerizing ethylene and a second α -olefin, the weight average molecular weight of the first polymer is more than 250 ten thousand, and the content of the first polymer is more than 5% by taking the total mass of the polymer composition as 100%.
In a specific embodiment, the first polymer has a weight average molecular weight of 400 to 1100 ten thousand.
In a specific embodiment, the first polymer has a weight average molecular weight of 420 to 1080 ten thousand.
In one embodiment, the first polymer is present in an amount of 5.3% to 7.2% based on 100% of the total mass of the polymer composition.
In a specific embodiment, the first α -olefin and the second α -olefin independently comprise at least one of propylene, 1-butene, 1-hexene, and 1-octene.
In one embodiment, the polymer composition has a Melt Flow Rate (MFR) (190, 21.6) less than 1 and a melt flow ratio (FFR) greater than 70.
In one embodiment, the polymer composition has a Melt Flow Rate (MFR) (190, 21.6) from 0.3 to 0.8 and a melt flow ratio (FFR) from 72 to 98.
In one embodiment, the polymer composition has a density greater than 940kg/cm3。
In one embodiment, the polymer composition has a density of 945kg/cm3To 952kg/cm3。
In one embodiment, the polymer composition has a density of 946kg/cm3To 952kg/cm3。
The second aspect of the invention provides a process for the preparation of a polymer composition according to any one of the first to the second aspects of the invention, comprising the steps of:
1) feeding a first material and a second material to a first reactor, wherein a polymerization reaction occurs to produce a first ethylene homopolymer as a first polymer, thereby obtaining a first mixture comprising the first polymer; wherein the first material comprises a polymerization catalyst and optionally a polymerization co-catalyst and the second material comprises ethylene and a first diluent;
2) passing the first mixture into a second reactor and feeding a second material comprising ethylene, a second diluent, hydrogen, and optionally a first α -olefin into the second reactor, in which a polymerization reaction occurs to produce a second ethylene homopolymer as a second polymer or a first copolymer formed by copolymerizing the ethylene and the first α -olefin, thereby obtaining a second mixture comprising the first polymer and the second polymer;
3) passing the second mixture into a third reactor and feeding a third feed to the third reactor, the third feed comprising ethylene, a third diluent, and hydrogen, optionally a second α -olefin, wherein polymerization occurs to produce a third ethylene homopolymer as a third polymer or a second copolymer formed by copolymerizing the ethylene and the second α -olefin, thereby producing a third mixture comprising the first polymer, the second polymer, and the third polymer;
wherein the molar flow ratio of hydrogen to ethylene in the third material is greater than the molar flow ratio of hydrogen to ethylene in the second material.
In one embodiment, the molar flow ratio of hydrogen to ethylene in the third material is more than one times greater than the molar flow ratio of hydrogen to ethylene in the second material.
In one embodiment, the volume of the first reactor is less than 5% of the sum of the volumes of the second reactor and the third reactor.
In one embodiment, the volume of the first reactor is less than 5% of the sum of the volumes of the second reactor and the third reactor, and the volume of the first reactor is greater than 1% of the sum of the volumes of the second reactor and the third reactor.
In a specific embodiment, the volume of the first reactor is more than 2% of the sum of the volumes of the second reactor and the third reactor.
In one embodiment, the volume of the first reactor is less than 3.3% of the sum of the volumes of the second and third reactors, and the volume of the first reactor is greater than 2% of the sum of the volumes of the second and third reactors.
In a specific embodiment, the polymerization catalyst comprises at least one of a ziegler-natta catalyst, a chromium-based catalyst, a metallocene catalyst, a non-metallocene single site catalyst.
In one embodiment, the polymerization catalyst is a titanium and magnesium forming Ziegler-Natta catalyst.
In one embodiment, for a Ziegler-Natta catalyst, the polymerization co-catalyst is triethylaluminum.
In one embodiment, for metallocene catalysts, the polymerization cocatalyst is methylaluminoxane.
In a specific embodiment, the first, second and third diluents independently comprise at least one of propane, isobutane, n-pentane, isopentane, cyclopentane, hexane and heptane.
In a specific embodiment, the first diluent, second diluent, and third diluent independently comprise propane and/or isobutane.
In one embodiment, the temperature of the polymerization reaction in the first reactor is not higher than 70 ℃.
In one embodiment, the temperature of the polymerization reaction in the first reactor is from 65 ℃ to 68 ℃.
In a specific embodiment, the polymerization temperature in the second reactor and the third reactor is independently from 70 ℃ to 120 ℃.
In a specific embodiment, the polymerization temperature in the second reactor and the third reactor is independently from 85 ℃ to 90 ℃.
In a specific embodiment, the polymerization pressure in the first reactor, the second reactor, and the third reactor is independently from 0.6MPa to 10 MPa.
In a specific embodiment, the polymerization pressure in the first reactor, the second reactor, and the third reactor is independently from 2.5MPa to 4 MPa.
In one embodiment, α -olefin (which may be, for example, the first α -olefin, the second α -olefin, or a α -olefin different from the first α -olefin and the second α -olefin) and hydrogen are not included in the first feed.
In a specific embodiment, the polymerization catalyst and polymerization co-catalyst are not independently included in the second material and the third material.
The third aspect of the invention provides the use of a polymer composition according to any one of the first to third aspects of the invention or a polymer composition prepared by a process according to any one of the second to third aspects of the invention.
In a particular embodiment, the application is in the preparation of pipes and/or geomembranes.
The fourth aspect of the present invention provides an apparatus for preparing the polymer composition according to any one of the first aspect of the present invention or the method according to any one of the second aspect of the present invention, comprising a first reactor, a second reactor and a third reactor connected in series in this order, wherein the first reactor, the second reactor and the third reactor are independently a loop reactor with a cooling jacket, and the first reactor is provided with a first inlet, a second inlet and a first outlet; a third feeding hole, a fourth feeding hole and a second discharging hole are formed in the second reactor; and a fifth feeding hole, a sixth feeding hole and a third discharging hole are formed in the third reactor.
In one embodiment, the volume of the first reactor is less than 5% of the sum of the volumes of the second reactor and the third reactor.
In one embodiment, the volume of the first reactor is less than 5% of the sum of the volumes of the second reactor and the third reactor, and the volume of the first reactor is greater than 1% of the sum of the volumes of the second reactor and the third reactor.
In one embodiment, the volume of the first reactor is less than 3.3% of the sum of the volumes of the second and third reactors, and the volume of the first reactor is greater than 2% of the sum of the volumes of the second and third reactors.
In one embodiment, the first reactor, the second reactor and the third reactor control the respective temperatures by independently controlling the flow of cooling water into the cooling jackets.
In a specific embodiment, the apparatus further comprises a separation device in series with the third reactor to separate the polymer composition from the third mixture via the separation device. Wherein the third mixture may be discharged from a third discharge port and then enter the separation device.
The invention has the beneficial effects that:
the invention provides a method for preparing high-performance multimodal polyethylene, which comprises the series sequence of polymerization reactors, the limitation of the reactor volume and the preferable conditions and the limited conditions of the reaction. By applying the invention, polyethylene products with better performance from in-situ polymerization of ultra-long molecular chains to a multimodal structure can be obtained, and the polyethylene products are more economical. The multimodal product containing the ultra-high molecular weight polyethylene has excellent performance in both use and processing, and can meet the application requirements of pipelines, geomembranes and the like on higher melt strength.
Drawings
Figure 1 shows a process flow diagram of the present invention.
The designations in the figures have the following meanings:
1a first loop reactor; 2 a first feed inlet; 3a second feed inlet; 4. 6a first loop reactor cooling water inlet; 5. 7 a first loop reactor cooling water outlet; 8, a first discharge hole; 9 a second loop reactor; 10 a third feed inlet; 11 a fourth feed port; 12. 14 a second loop reactor cooling water inlet; 13. 15 a second loop reactor cooling water outlet; 16 a second discharge port; 17 a third loop reactor; 18 a fifth feed port; 19 a sixth feed opening; 20. 22 a third loop reactor cooling water inlet; 21. 23 a third loop reactor cooling water outlet; 24 a third discharge port; 25. 26, 27 loop reactor cooling jackets.
FIG. 2 shows the weight average molecular weight distribution curve of the composition of example 1.
Figure 3 shows the weight average molecular weight distribution curve for the composition of example 2.
Figure 4 shows the weight average molecular weight distribution curve for the composition of example 3.
Fig. 5 shows the weight average molecular weight distribution curve of the composition of comparative example 1.
Fig. 6 shows a weight average molecular weight distribution curve of the composition of comparative example 2.
Fig. 7 shows a weight average molecular weight distribution curve of the composition of comparative example 3.
Detailed Description
The present invention is further illustrated by the following examples, which are intended to be purely exemplary of the invention and are not to be construed as limiting the invention in any way.
The present invention uses a slurry polymerization process to produce ethylene, α -olefin trimodal copolymer by operating three loop reactors in series, namely a first loop reactor 1, a second loop reactor 9 and a third loop reactor 16. under the guidance of the present invention, the skilled person can conceive of any possible variants based on the present invention, which should be considered as falling within the scope of the present invention, for example adding to the prepolymerization process mentioned in patent CN105793291A, or using other forms of polymerization reactors, or using more reactors in series, parallel to achieve other similar processes in the present invention without phase separation of ethylene, α -olefin co-polyethylene.
The weight average molecular weight and weight average molecular weight distribution curves of the first polymer and composition were determined using the Gel Permeation Chromatography (GPC) method in ISO16014 standards.
The Melt Flow Rate (MFR) is determined according to the method in standard GBT3682 at a temperature of 190 ℃ and under a load of 2.16kg or 21.6kg, and is expressed as MFR (190, 2.16) and MFR (190, 21.6), respectively, in that order.
The melt flow ratio (FFR) is the ratio of MFR (190, 21.6) to MFR (190, 2.16).
The density of the composition obtained after devolatilization was measured by the method in ASTM D1503.
Example 1
As shown in fig. 1, the first loop reactor 1, the second loop reactor 9 and the third loop reactor 17 are provided with loop reactor cooling jackets 25, 26, 27, respectively. Wherein cooling water from the cooling jacket of the first loop reactor 1 enters from first loop reactor cooling water inlets 4 and 6 and exits from first loop reactor cooling water outlets 5 and 7. Cooling water from the cooling jacket of the second loop reactor 9 enters through second loop reactor cooling water inlets 12 and 14 and exits through second loop reactor cooling water outlets 13 and 15. Cooling water from the cooling jacket of the third loop reactor 17 enters through third loop reactor cooling water inlets 20 and 22 and exits through third loop reactor cooling water outlets 21 and 23.
As shown in FIG. 1, the volume of the first feed inlet 2 is 2.6m from the first loop reactor 13(V1) 0.5kg/hr of a Ziegler-Natta catalyst (prepared by a process as disclosed in EP 810235) and 1.5kg/hr of triethylaluminium as cocatalyst are fed to the first loop reactor 1. At the same time, 500kg/hr of ethylene and 5000kg/hr of isobutane were fed to the first loop reactor 1 through the second feed port 3 provided in the first loop reactor 1. A polymerization reaction takes place in the first loop reactor 1 to produce ethylene homopolymer as the first polymer, resulting in a first mixture of first polymers. Wherein the polymerization temperature in the first loop reactor 1 is controlled at 70 ℃ (T) by adjusting the flow rate of the cooling water at the cooling water inlet 4, 6 of the first loop reactor 11) The discharge flow rate of the first mixture at the first discharge port 8 of the first loop reactor 1 is adjusted to control the polymerization pressure in the first loop reactor 1 to be 4.0MPa (P)1)。
The first mixture was continuously withdrawn from the first outlet 8 of the first loop reactor 1 and introduced in its entirety from the third inlet 10 of the second loop reactor 9 into a volume of 23m3(V2) Second ring pipe ofIn the reactor 9. At the same time, 3750kg/hr of ethylene, 0.5kg/hr of hydrogen, 30kg/hr of 1-hexene and 5000kg/hr of isobutane were fed into the second loop reactor 9 through the fourth feed port 11 provided in the second loop reactor 9. Polymerization takes place in the second loop reactor 9 to produce ethylene-1-hexene copolymer as the second polymer, resulting in a second mixture containing the first polymer and the second polymer. Wherein the polymerization temperature in the second loop reactor 9 is controlled to 90 ℃ (T) by adjusting the flow rate of the cooling water at the cooling water inlets 12, 14 of the second loop reactor 92) The discharge flow rate of the second mixture from the second discharge port 16 of the second loop reactor 9 was adjusted to control the polymerization pressure in the second loop reactor 9 to 3.9MPa (P)2)。
The second mixture was continuously withdrawn from the second outlet 16 of the second loop reactor 9 and introduced in its entirety into a fifth inlet 18 of 63m volume, located on the third loop reactor 173(V3) In the third loop reactor 17. At the same time, 3000kg/hr of ethylene, 4kg/hr of hydrogen and 4000kg/hr of isobutane were fed to the third loop reactor 17 from a sixth feed port 19 located above the third loop reactor 17. A polymerization reaction takes place in the third loop reactor 17 to produce ethylene homopolymer as the third polymer, resulting in a third mixture comprising the first polymer, the second polymer and the third polymer. Wherein the polymerization temperature in the third loop reactor 17 is controlled to 90 deg.C (T) by adjusting the flow rate of the cooling water at the cooling water inlets 20, 22 of the third loop reactor 173) The discharge flow rate of the third mixture at the third discharge port 24 of the third loop reactor 17 is adjusted to control the polymerization pressure in the third loop reactor 17 to 3.8MPa (P)3)。
The third mixture was continuously withdrawn from the third outlet 24 of the third loop reactor 17 and then removed of the hydrocarbons and residual catalyst contained therein by the devolatilization process in CN 101955554A. Specifically, the third mixture first enters a high pressure flash tank. And then separated from the top of the high-pressure flash tankThe gas phase enters a recovery system through the processes of cyclone, filtration, condensation and the like; introducing the solid powder separated from the bottom of the high-pressure flash tank into a low-pressure flash chamber, removing residual hydrocarbons and inactivating residual catalyst in the low-pressure flash chamber to obtain a composition of the first polymer, the second polymer and the third polymer, wherein the weight of the composition is 6367kg/hr (W)1+2+3)。
The weight average molecular weight distribution curve of the composition obtained after devolatilization is shown in FIG. 2. As can be seen, the molecular weight distribution of the composition prepared in this example is a trimodal distribution.
Weight average molecular weight of the first polymer, mass flow rate W of the first mixture1The values of important parameters such as MFR (190, 21.6) of the composition, FFR of the composition, density of the composition are shown in Table 1.
Example 2
As shown in fig. 1, the first loop reactor 1, the second loop reactor 9 and the third loop reactor 17 are provided with loop reactor cooling jackets 25, 26, 27, respectively. Wherein cooling water from the cooling jacket of the first loop reactor 1 enters from first loop reactor cooling water inlets 4 and 6 and exits from first loop reactor cooling water outlets 5 and 7. Cooling water from the cooling jacket of the second loop reactor 9 enters through second loop reactor cooling water inlets 12 and 14 and exits through second loop reactor cooling water outlets 13 and 15. Cooling water from the cooling jacket of the third loop reactor 17 enters through third loop reactor cooling water inlets 20 and 22 and exits through third loop reactor cooling water outlets 21 and 23.
As shown in FIG. 1, the volume of the first feed inlet 2 of the first loop reactor 1 is 2.7m3(V1) 0.5kg/hr of the Ziegler-Natta catalyst of example 1 and 1.5kg/hr of triethylaluminium as cocatalyst were fed to the first loop reactor 1. At the same time, 650kg/hr of ethylene and 5000kg/hr of hexane were fed into the first loop reactor 1 through the second feed port 3 provided in the first loop reactor 1. A polymerization reaction takes place in the first loop reactor 1 to produce ethylene homopolymer as the first polymer, resulting in a first mixture of first polymers. Wherein the reaction is carried out in the first loop by regulationThe flow rate of the cooling water at the cooling water inlets 4, 6 of the first loop reactor 1 is such that the polymerization temperature in the first loop reactor 1 is controlled at 65 deg.C (T)1) The discharge flow rate of the first mixture at a first discharge port 8 of the first loop reactor 1 is adjusted to control the polymerization pressure in the first loop reactor 1 to 2.5MPa (P)1)。
The first mixture was continuously withdrawn from the first outlet 8 of the first loop reactor 1 and introduced in its entirety into a volume of 40m from the third inlet 10 of the second loop reactor 93(V2) In the second loop reactor 9. At the same time, 3750kg/hr of ethylene, 0.4kg/hr of hydrogen, 30kg/hr of 1-butene and 7000kg/hr of hexane were fed into the second loop reactor 9 through the fourth feed port 11 provided in the second loop reactor 9. Polymerization takes place in the second loop reactor 9 to produce ethylene-1-butene copolymer as the second polymer, thereby obtaining a second mixture comprising the first polymer and the second polymer. Wherein the polymerization temperature in the second loop reactor 9 is controlled to 85 ℃ (T) by adjusting the flow rate of the cooling water at the cooling water inlets 12, 14 of the second loop reactor 92) The discharge flow rate of the second mixture from the second discharge port 16 of the second loop reactor 9 was adjusted to control the polymerization pressure in the second loop reactor 9 to 2.5MPa (P)2)。
The second mixture was continuously withdrawn from a second outlet 16 of the second loop reactor 9 and was introduced in its entirety into a fifth inlet 18 of 41m volume, located in a third loop reactor 173(V3) In the third loop reactor 17. At the same time, 3000kg/hr of ethylene, 6kg/hr of hydrogen and 2000kg/hr of hexane were fed into the third loop reactor 17 from a sixth feed port 19 provided in the third loop reactor 17. A polymerization reaction takes place in the third loop reactor 17 to produce ethylene homopolymer as the third polymer, resulting in a third mixture comprising the first polymer, the second polymer and the third polymer. Wherein the flow rate of the cooling water inlets 20, 22 of the third loop reactor 17 is adjusted so that the cooling water flows through the third loop reactorThe polymerization temperature in the third loop reactor 17 was controlled at 85 deg.C (T)3) The discharge flow rate of the third mixture at the third discharge port 24 of the third loop reactor 17 is adjusted to control the polymerization pressure in the third loop reactor 17 to 3.8MPa (P)3)。
The procedure for separating the composition of the first polymer, the second polymer and the third polymer from the third mixture was the same as in example 1, and the weight of the composition was 6462kg/hr (W)1+2+3)。
The weight average molecular weight distribution curve of the composition obtained after devolatilization is shown in FIG. 3. As can be seen, the molecular weight distribution of the composition prepared in this example is a trimodal distribution.
Weight average molecular weight of the first polymer, mass flow rate W of the first mixture1The values of important parameters such as MFR (190, 21.6) of the composition, FFR of the composition, density of the composition are shown in Table 1.
Example 3
As shown in fig. 1, the first loop reactor 1, the second loop reactor 9 and the third loop reactor 17 are provided with loop reactor cooling jackets 25, 26, 27, respectively. Wherein cooling water from the cooling jacket of the first loop reactor 1 enters from first loop reactor cooling water inlets 4 and 6 and exits from first loop reactor cooling water outlets 5 and 7. Cooling water from the cooling jacket of the second loop reactor 9 enters through second loop reactor cooling water inlets 12 and 14 and exits through second loop reactor cooling water outlets 13 and 15. Cooling water from the cooling jacket of the third loop reactor 17 enters through third loop reactor cooling water inlets 20 and 22 and exits through third loop reactor cooling water outlets 21 and 23.
As shown in FIG. 1, the volume of the first feed inlet 2 is 1.6m from the first loop reactor 13(V1) 0.5kg/hr of the Ziegler-Natta catalyst of example 1 and 1.5kg/hr of triethylaluminium as cocatalyst were fed to the first loop reactor 1. At the same time, 950kg/hr of ethylene and 5000kg/hr of hexane were fed into the first loop reactor 1 through the second feed port 3 provided in the first loop reactor 1. The polymerization reaction takes place in the first loop reactor 1 asEthylene homopolymer of the first polymer, thereby obtaining a first mixture of the first polymer. Wherein the polymerization temperature in the first loop reactor 1 is controlled to 68 ℃ (T) by adjusting the flow rate of the cooling water at the cooling water inlets 4, 6 of the first loop reactor 11) The discharge flow rate of the first mixture at a first discharge port 8 of the first loop reactor 1 is adjusted to control the polymerization pressure in the first loop reactor 1 to 2.5MPa (P)1)。
The first mixture was continuously withdrawn from the first outlet 8 of the first loop reactor 1 and introduced in its entirety into a volume of 40m from the third inlet 10 of the second loop reactor 93(V2) In the second loop reactor 9. At the same time, 3750kg/hr of ethylene, 0.4kg/hr of hydrogen, 30kg/hr of 1-butene and 7000kg/hr of hexane were fed into the second loop reactor 9 through the fourth feed port 11 provided in the second loop reactor 9. Polymerization takes place in the second loop reactor 9 to produce ethylene-1-butene copolymer as the second polymer, thereby obtaining a second mixture comprising the first polymer and the second polymer. Wherein the polymerization temperature in the second loop reactor 9 is controlled to 85 ℃ (T) by adjusting the flow rate of the cooling water at the cooling water inlets 12, 14 of the second loop reactor 92) The discharge flow rate of the second mixture from the second discharge port 16 of the second loop reactor 9 was adjusted to control the polymerization pressure in the second loop reactor 9 to 2.5MPa (P)2)。
The second mixture was continuously withdrawn from the second outlet 16 of the second loop reactor 9 and introduced in its entirety into a fifth inlet 18 of 41m volume, located on the third loop reactor 173(V3) In the third loop reactor 17. At the same time, 3000kg/hr of ethylene, 6kg/hr of hydrogen and 2000kg/hr of hexane were fed into the third loop reactor 17 from a sixth feed port 19 provided in the third loop reactor 17. The polymerization reaction takes place in the third loop reactor 17 to produce ethylene homopolymer as the third polymer, thereby obtaining a third mixture comprising the first polymer, the second polymer and the third polymer. Wherein the polymerization temperature in the third loop reactor 17 is controlled to 85 ℃ (T) by adjusting the flow rate of the cooling water at the cooling water inlet 20, 22 of the third loop reactor 173) The discharge flow rate of the third mixture at the third discharge port 24 of the third loop reactor 17 is adjusted to control the polymerization pressure in the third loop reactor 17 to 3.8MPa (P)3)。
The procedure for separating the composition of the first, second and third polymers was as in example 1, and the weight of the composition was 6696kg/hr (W)1+2+3)。
The weight average molecular weight distribution curve of the composition obtained after devolatilization is shown in FIG. 4. As can be seen, the molecular weight distribution of the composition prepared in this example is a trimodal distribution.
Weight average molecular weight of the first polymer, mass flow rate W of the first mixture1The values of important parameters such as MFR (190, 21.6) of the composition, FFR of the composition, density of the composition are shown in Table 1.
Comparative example 1
As shown in fig. 1, the first loop reactor 1, the second loop reactor 9 and the third loop reactor 17 are provided with loop reactor cooling jackets 25, 26, 27, respectively. Wherein cooling water from the cooling jacket of the first loop reactor 1 enters from first loop reactor cooling water inlets 4 and 6 and exits from first loop reactor cooling water outlets 5 and 7. Cooling water from the cooling jacket of the second loop reactor 9 enters through second loop reactor cooling water inlets 12 and 14 and exits through second loop reactor cooling water outlets 13 and 15. Cooling water from the cooling jacket of the third loop reactor 17 enters through third loop reactor cooling water inlets 20 and 22 and exits through third loop reactor cooling water outlets 21 and 23.
As shown in FIG. 1, the volume of the first feed inlet 2 is 4.4m from the first loop reactor 13(V1) 0.5kg/hr of the Ziegler-Natta catalyst of example 1 and 1.5kg/hr of triethylaluminium as cocatalyst were fed to the first loop reactor 1. Simultaneously from the second feed opening 3 located on the first loop reactor 1 to the first loop reactor1, 650kg/hr of ethylene and 5000kg/hr of hexane were added. A polymerization reaction takes place in the first loop reactor 1 to produce ethylene homopolymer as the first polymer, resulting in a first mixture of first polymers. Wherein the polymerization temperature in the first loop reactor 1 is controlled to 65 ℃ (T) by adjusting the flow rate of the cooling water at the cooling water inlet 4, 6 of the first loop reactor 11) The polymerization pressure in the first loop reactor 1 was controlled to 2.5MPa (P) by adjusting the discharge flow rate of the first mixture at the first discharge port 8 of the first loop reactor 11)。
The first mixture was continuously withdrawn from the first outlet 8 of the first loop reactor 1 and introduced in its entirety into a volume of 40m from the third inlet 10 of the second loop reactor 93(V2) In the second loop reactor 9. At the same time, 3750kg/hr of ethylene, 0.4kg/hr of hydrogen, 30kg/hr of 1-butene and 7000kg/hr of hexane were fed into the second loop reactor 9 through the fourth feed port 11 provided in the second loop reactor 9. Polymerization takes place in the second loop reactor 9 to produce ethylene-1-butene copolymer as the second polymer, thereby obtaining a second mixture comprising the first polymer and the second polymer. Wherein the polymerization temperature in the second loop reactor 9 is controlled to 85 ℃ (T) by adjusting the flow rate of the cooling water at the cooling water inlets 12, 14 of the second loop reactor 92) The discharge flow rate of the second mixture from the second discharge port 16 of the second loop reactor 9 was adjusted to control the polymerization pressure in the second loop reactor 9 to 2.5MPa (P)2)。
The second mixture was continuously withdrawn from the second outlet 16 of the second loop reactor 9 and introduced in its entirety into a fifth inlet 18 of 41m volume, located on the third loop reactor 173(V3) In the third loop reactor 17. At the same time, 3000kg/hr of ethylene, 6kg/hr of hydrogen and 2000kg/hr of hexane were fed into the third loop reactor 17 from a sixth feed port 19 provided in the third loop reactor 17. The polymerization reaction in the third loop reactor 17 takes place to produce ethylene as a third polymerAnd (c) a homopolymer, thereby obtaining a third mixture comprising the first polymer, the second polymer, and the third polymer. Wherein the polymerization temperature in the third loop reactor 17 is controlled to 85 ℃ (T) by adjusting the flow rate of the cooling water at the cooling water inlet 20, 22 of the third loop reactor 173) The discharge flow rate of the third mixture at the third discharge port 24 of the third loop reactor 17 is adjusted to control the polymerization pressure in the third loop reactor 17 to 3.8MPa (P)3)。
The procedure for separating the composition of the first polymer, the second polymer and the third polymer from the third mixture was the same as in example 1, and the weight of the composition was 6488kg/hr (W)1+2+3)。
The weight average molecular weight distribution curve of the composition obtained after devolatilization is shown in FIG. 5. As can be seen, the molecular weight distribution of the composition prepared in this example is a trimodal distribution.
Weight average molecular weight of the first polymer, mass flow rate W of the first mixture1The values of important parameters such as MFR (190, 21.6) of the composition, FFR of the composition, density of the composition are shown in Table 1.
Comparative example 2
As shown in fig. 1, the first loop reactor 1, the second loop reactor 9 and the third loop reactor 17 are provided with loop reactor cooling jackets 25, 26, 27, respectively. Wherein cooling water from the cooling jacket of the first loop reactor 1 enters from first loop reactor cooling water inlets 4 and 6 and exits from first loop reactor cooling water outlets 5 and 7. Cooling water from the cooling jacket of the second loop reactor 9 enters through second loop reactor cooling water inlets 12 and 14 and exits through second loop reactor cooling water outlets 13 and 15. Cooling water from the cooling jacket of the third loop reactor 17 enters through third loop reactor cooling water inlets 20 and 22 and exits through third loop reactor cooling water outlets 21 and 23.
As shown in FIG. 1, the volume of the first feed inlet 2 of the first loop reactor 1 is 3.6m3(V1) 0.5kg/hr of the Ziegler-Natta catalyst of example 1 and 1.5kg/hr of triethylaluminum as cocatalyst. At the same time, 650kg/hr of ethylene and 5000kg/hr of hexane were fed into the first loop reactor 1 through the second feed port 3 provided in the first loop reactor 1. A polymerization reaction takes place in the first loop reactor 1 to produce ethylene homopolymer as the first polymer, resulting in a first mixture of first polymers. Wherein the polymerization temperature in the first loop reactor 1 is controlled to 80 ℃ (T) by adjusting the flow rate of the cooling water at the cooling water inlets 4, 6 of the first loop reactor 11) The discharge flow rate of the first mixture at a first discharge port 8 of the first loop reactor 1 is adjusted to control the polymerization pressure in the first loop reactor 1 to 2.5MPa (P)1)。
The first mixture was continuously withdrawn from the first outlet 8 of the first loop reactor 1 and introduced in its entirety into a volume of 40m from the third inlet 10 of the second loop reactor 93(V2) In the second loop reactor 9. While 3750kg/hr of ethylene, 0.4kg/hr of hydrogen, 30kg/hr of 1-butene and 7000kg/hr of hexane were fed to the second loop reactor 9 through the fourth feed port 11 provided in the second loop reactor 9. Polymerization takes place in the second loop reactor 9 to produce ethylene-1-butene copolymer as the second polymer, thereby obtaining a second mixture comprising the first polymer and the second polymer. Wherein the polymerization temperature in the second loop reactor 9 is controlled to 85 ℃ (T) by adjusting the flow rate of the cooling water at the cooling water inlets 12, 14 of the second loop reactor 92) The discharge flow rate of the second mixture from the second discharge port 16 of the second loop reactor 9 was adjusted to control the polymerization pressure in the second loop reactor 9 to 2.5MPa (P)2)。
The second mixture was continuously withdrawn from the second outlet 16 of the second loop reactor 9 and introduced in its entirety into a fifth inlet 18 of 41m volume, located on the third loop reactor 173(V3) In the third loop reactor 17. At the same time, the feed is introduced into the third loop reactor 17 from a sixth feed opening 19 located in the third loop reactor 173000kg/hr of ethylene, 6kg/hr of hydrogen and 2000kg/hr of hexane. A polymerization reaction takes place in the third loop reactor 17 to produce ethylene homopolymer as the third polymer, resulting in a third mixture comprising the first polymer, the second polymer and the third polymer. Wherein the polymerization temperature in the third loop reactor 17 is controlled to 85 ℃ (T) by adjusting the flow rate of the cooling water at the cooling water inlet 20, 22 of the third loop reactor 173) The discharge flow rate of the third mixture at the third discharge port 24 of the third loop reactor 17 is adjusted to control the polymerization pressure in the third loop reactor 17 to 3.8MPa (P)3)。
The procedure for separating the composition of the first polymer, the second polymer and the third polymer from the third mixture was the same as in example 1, and the weight of the composition was 6463kg/hr (W)1+2+3)。
The weight average molecular weight distribution curve of the composition obtained after devolatilization is shown in FIG. 6. As can be seen, the molecular weight distribution of the composition prepared in this example is a trimodal distribution.
Weight average molecular weight of the first polymer, mass flow rate W of the first mixture1The values of important parameters such as MFR (190, 21.6) of the composition, FFR of the composition, density of the composition are shown in Table 1.
Comparative example 3
As shown in fig. 1, the first loop reactor 1, the second loop reactor 9 and the third loop reactor 17 are provided with loop reactor cooling jackets 25, 26, 27, respectively. Wherein cooling water from the cooling jacket of the first loop reactor 1 enters from first loop reactor cooling water inlets 4 and 6 and exits from first loop reactor cooling water outlets 5 and 7. Cooling water from the cooling jacket of the second loop reactor 9 enters through second loop reactor cooling water inlets 12 and 14 and exits through second loop reactor cooling water outlets 13 and 15. Cooling water from the cooling jacket of the third loop reactor 17 enters through third loop reactor cooling water inlets 20 and 22 and exits through third loop reactor cooling water outlets 21 and 23.
As shown in fig. 1, from a first feed inlet 2 located on a first loop reactor 1Volume of 40m3(V1) 0.5kg/hr of the Ziegler-Natta catalyst of example 1 and 1.5kg/hr of triethylaluminium as cocatalyst were fed to the first loop reactor 1. At the same time, 3750kg/hr of ethylene, 0.4kg/hr of hydrogen, 30kg/hr of 1-butene and 7000kg/hr of hexane were fed into the first loop reactor 1 through the second feed port 3 provided in the first loop reactor 1. A polymerization reaction takes place in the first loop reactor 1 to produce ethylene-1-butene copolymer as the first polymer, thereby obtaining a first mixture of the first polymer. Wherein the polymerization temperature in the first loop reactor 1 is controlled to 85 ℃ (T) by adjusting the flow rate of the cooling water at the cooling water inlets 4, 6 of the first loop reactor 11) The discharge flow rate of the first mixture at a first discharge port 8 of the first loop reactor 1 is adjusted to control the polymerization pressure in the first loop reactor 1 to 2.5MPa (P)1)。
The first mixture was continuously withdrawn from a first outlet 8 of the first loop reactor 1 and introduced in its entirety into a volume of 2.6m from a third inlet 10 of the second loop reactor 93(V2) In the second loop reactor 9. At the same time, 650kg/hr of ethylene and 5000kg/hr of hexane were fed to the second loop reactor 9 through the fourth feed port 11 provided in the second loop reactor 9. In the second loop reactor 9 a polymerization reaction takes place to form ethylene homopolymer as the second polymer, resulting in a second mixture comprising the first polymer and the second polymer. Wherein the polymerization temperature in the second loop reactor 9 is controlled to 65 deg.C (T.sub.m) by adjusting the flow rate of the cooling water at the cooling water inlets 12, 14 of the second loop reactor 92) The discharge flow rate of the second mixture from the second discharge port 16 of the second loop reactor 9 was adjusted to control the polymerization pressure in the second loop reactor 9 to 2.5MPa (P)2)。
The second mixture was continuously withdrawn from the second outlet 16 of the second loop reactor 9 and introduced in its entirety into a fifth inlet 18 of 41m volume, located on the third loop reactor 173(V3) In the third loop reactor 17. At the same time, 3000kg/hr of ethylene, 6kg/hr of hydrogen and 2000kg/hr of hexane were fed into the third loop reactor 17 from a sixth feed port 19 provided in the third loop reactor 17. A polymerization reaction takes place in the third loop reactor 17 to produce ethylene homopolymer as the third polymer, resulting in a third mixture comprising the first polymer, the second polymer and the third polymer. Wherein the polymerization temperature in the third loop reactor 17 is controlled to 85 ℃ (T) by adjusting the flow rate of the cooling water at the cooling water inlet 20, 22 of the third loop reactor 173) The discharge flow rate of the third mixture at the third discharge port 24 of the third loop reactor 17 is adjusted to control the polymerization pressure in the third loop reactor 17 to 3.8MPa (P)3)。
The procedure for separating the composition of the first polymer, the second polymer and the third polymer from the third mixture was the same as in example 1, and the weight of the composition was 6473kg/hr (W)1+2+3)。
The weight average molecular weight distribution curve of the composition obtained after devolatilization is shown in FIG. 7. As can be seen, the molecular weight distribution of the composition prepared in this example is unimodal.
Weight average molecular weight of the first polymer, mass flow rate W of the first mixture1The values of important parameters such as MFR (190, 21.6) of the composition, FFR of the composition, density of the composition are shown in Table 1.
TABLE 1
| Example 1 | Example 2 | Example 3 | Comparative example 1 | Comparative example 2 | Comparative example 3 | |
| V1(m3) | 2.6 | 2.7 | 1.6 | 4.4 | 3.6 | 40 |
| V2(m3) | 23 | 40 | 40 | 40 | 40 | 2.6 |
| V3(m3) | 63 | 41 | 41 | 41 | 41 | 41 |
| V1/(V2+V3)×100％ | 3.0％ | 3.3％ | 2.0％ | 5.4％ | 4.4％ | 91.7％ |
| T1(℃) | 70 | 65 | 68 | 65 | 80 | 85 |
| T2(℃) | 90 | 85 | 85 | 85 | 85 | 65 |
| T3(℃) | 90 | 85 | 85 | 85 | 85 | 85 |
| P1(MPa) | 4.0 | 2.5 | 2.5 | 2.5 | 2.5 | 2.5 |
| P2(MPa) | 3.9 | 2.5 | 2.5 | 2.5 | 2.5 | 2.5 |
| P3(MPa) | 3.8 | 3.8 | 3.8 | 3.8 | 3.8 | 3.8 |
| Weight average molecular weight of the first polymer | 2958925 | 4248272 | 8994298 | 2199868 | 1880940 | 186711 |
| Mass flow rate W of the first mixture1(kg/hr) | 337 | 468 | 412 | 557 | 546 | 3582 |
| Weight average molecular weight of the second Polymer | — | — | — | — | — | 699469 |
| Mass flow rate W of the second mixture2(kg/hr) | — | — | — | — | — | 195 |
| Weight average molecular weight of the third Polymer | — | — | — | — | — | — |
| Mass flow rate W of the third mixture3(kg/hr) | — | — | — | — | — | — |
| MFR (190, 21.6) of the composition | 0.8 | 0.4 | 0.1 | 1.0 | 1.1 | 28 |
| FFR of the composition | 72 | 96 | 134 | 80 | 76 | 42 |
| Density of the composition (kg/m)3) | 952 | 946 | 950 | 950 | 950 | 948 |
| W1+2+3(kg/hr) | 6367 | 6462 | 6696 | 6488 | 6463 | 6473 |
| W1/W1+2+3×100％ | 5.3％ | 7.2％ | 6.2％ | 8.6％ | 8.4％ | 55.3％ |
| W2/W1+2+3×100％ | — | — | — | — | — | 3.0％ |
| W3/W1+2+3×100％ | — | — | — | — | — | — |
Note: "-" indicates not measured.
Claims (15)
1. A polymer composition comprises a first polymer, a second polymer and a third polymer, wherein the first polymer is a first ethylene homopolymer, the second polymer is a second ethylene homopolymer or a first copolymer formed by copolymerizing ethylene and a first α -olefin, the third polymer is a third ethylene homopolymer or a second copolymer formed by copolymerizing ethylene and a second α -olefin, the weight average molecular weight of the first polymer is more than 250 ten thousand, the content of the first polymer is more than 5 percent based on 100 percent of the total mass of the polymer composition;
preferably, the first polymer has a weight average molecular weight of 400 to 1100 ten thousand;
preferably, the content of the first polymer is 5.3% to 7.2% by mass based on 100% by mass of the total polymer composition.
2. The polymer composition of claim 1, wherein the first α -olefin and the second α -olefin independently comprise at least one of propylene, 1-butene, 1-hexene, and 1-octene.
3. The polymer composition of claim 1 or 2, wherein the polymer composition has a melt flow rate (190, 21.6) of less than 1, a melt flow ratio of greater than 70; preferably, the polymer composition has a Melt Flow Rate (MFR) (190, 21.6) from 0.3 to 0.8 and a melt flow ratio (FFR) from 72 to 98.
4. The polymer composition according to any of claims 1 to 3, wherein the polymer composition has a density of more than 940kg/cm3(ii) a Preferably, the polymer composition has a density of 945kg/cm3To 952kg/cm3。
5. A process for preparing a polymer composition according to any one of claims 1 to 4, comprising the steps of:
1) feeding a first material and a second material to a first reactor, wherein a polymerization reaction occurs to produce a first ethylene homopolymer as a first polymer, thereby obtaining a first mixture comprising the first polymer; wherein the first material comprises a polymerization catalyst and optionally a polymerization co-catalyst and the second material comprises ethylene and a first diluent;
2) passing the first mixture into a second reactor and feeding a second material comprising ethylene, a second diluent, hydrogen, and optionally a first α -olefin into the second reactor, in which a polymerization reaction occurs to produce a second ethylene homopolymer as a second polymer or a first copolymer formed by copolymerizing the ethylene and the first α -olefin, thereby obtaining a second mixture comprising the first polymer and the second polymer;
3) passing the second mixture into a third reactor and feeding a third feed to the third reactor, the third feed comprising ethylene, a third diluent, hydrogen, and optionally a second α -olefin, in which a polymerization reaction occurs to produce a third ethylene homopolymer as a third polymer or a second copolymer formed by copolymerizing the ethylene and the second α -olefin, thereby obtaining a third mixture comprising the first polymer, the second polymer, and the third polymer;
wherein the molar flow ratio of hydrogen to ethylene in the third material is greater than the molar flow ratio of hydrogen to ethylene in the second material, preferably more than one time.
6. The process of claim 5, wherein the volume of the first reactor is less than 5% of the sum of the volume of the second reactor and the volume of the third reactor; preferably, the volume of the first reactor is less than 5% of the sum of the volumes of the second reactor and the third reactor, and the volume of the first reactor is more than 1% of the sum of the volumes of the second reactor and the third reactor; preferably, the volume of the first reactor is more than 2% of the sum of the volumes of the second reactor and the third reactor.
7. The process according to claim 5 or 6, wherein the polymerization catalyst comprises at least one of a Ziegler-Natta catalyst, a chromium based catalyst, a metallocene catalyst, a non-metallocene single site catalyst, preferably the polymerization catalyst is a Ziegler-Natta catalyst formed of titanium and magnesium; preferably, for a ziegler-natta catalyst, the polymerization co-catalyst is an aluminum alkyl, preferably, the polymerization co-catalyst is triethylaluminum; for metallocene catalysts, the polymerization cocatalyst is methylaluminoxane;
and/or
The first, second and third diluents independently comprise at least one of propane, isobutane, n-pentane, isopentane, cyclopentane, hexane and heptane, preferably the first, second and third diluents independently comprise propane and/or isobutane.
8. The process according to any one of claims 5 to 7, characterized in that in the first reactor the temperature of the polymerization reaction is not higher than 70 ℃, preferably from 65 ℃ to 68 ℃.
9. The process of any one of claims 5 to 8, wherein the polymerization temperature in the second reactor and the third reactor is independently 70 ℃ to 120 ℃; preferably, the polymerization temperature in the second reactor and the third reactor is independently from 85 ℃ to 90 ℃;
and/or
The polymerization pressure in the first, second and third reactors is independently from 0.6MPa to 10 MPa;
preferably, the polymerization pressure in the first reactor, the second reactor and the third reactor is independently from 2.5MPa to 4 MPa.
10. The method according to any one of claims 5 to 9, characterized in that α -olefin and hydrogen are not included in the first material and/or
The polymerization catalyst and polymerization co-catalyst are independently excluded from the second material and the third material.
11. Use of a polymer composition according to any one of claims 1 to 4 or prepared according to the process of any one of claims 5 to 10; preferably, the application is in the preparation of pipes and/or geomembranes.
12. An apparatus for preparing the polymer composition according to any one of claims 1 to 4 or the process according to any one of claims 5 to 10, comprising a first reactor, a second reactor and a third reactor connected in series in this order, wherein the first reactor, the second reactor and the third reactor are independently a loop reactor with a cooling jacket, and the first reactor is provided with a first inlet, a second inlet and a first outlet; a third feeding hole, a fourth feeding hole and a second discharging hole are formed in the second reactor; and a fifth feeding hole, a sixth feeding hole and a third discharging hole are formed in the third reactor.
13. The apparatus of claim 12, wherein the volume of the first reactor is less than 5% of the sum of the volumes of the second reactor and the third reactor; preferably, the volume of the first reactor is less than 5% of the sum of the volumes of the second reactor and the third reactor, and the volume of the first reactor is more than 1% of the sum of the volumes of the second reactor and the third reactor; preferably, the volume of the first reactor is less than 3.3% of the sum of the volumes of the second reactor and the third reactor, and the volume of the first reactor is more than 2% of the sum of the volumes of the second reactor and the third reactor.
14. The apparatus according to claim 12 or 13, wherein the first reactor, the second reactor and the third reactor control respective temperatures by independently controlling the flow rate of cooling water into the cooling jacket.
15. The apparatus of claim 12 or 13, further comprising a separation device in series with the third reactor to separate the polymer composition from the third mixture by the separation device.
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