WO2020107933A1

WO2020107933A1 - Catalyst suitable for producing polyolefin with ultra-fine particle size, preparation method therefor and use thereof

Info

Publication number: WO2020107933A1
Application number: PCT/CN2019/099340
Authority: WO
Inventors: 张乐天; 肖明威; 叶晓峰; 奚媛媛; 叶纯麟
Original assignee: 上海化工研究院有限公司; 上海联濮化工科技有限公司
Priority date: 2018-11-26
Filing date: 2019-08-06
Publication date: 2020-06-04
Also published as: CN109535290A; CN109535290B; MY188173A

Abstract

The invention relates to a catalyst suitable for producing a polyolefin with an ultra-fine particle size, a preparation method therefor and the use thereof. The catalyst comprises, as a first carrier, an inorganic carrier obtained by means of a surfactant treatment, as a second carrier, active magnesium chloride produced in situ on the first carrier with a magnesium-containing reagent, and a catalyst active component supported on the second carrier, wherein the catalyst active component is a Ziegler-Natta catalyst. Compared with the prior art, the catalyst of the present invention can be used to prepare a polyethylene product with a high bulk density, uniform particles and an average particle size of less than 200 microns, and can be used for preparing and applied in medium and high density polyolefins.

Description

Catalyst suitable for producing ultra-fine particle size polyolefin, preparation method and application thereof

Technical field

The invention relates to the technical field of catalysts, in particular to a catalyst suitable for producing ultra-fine particle size polyolefin and its preparation method and application.

Background technique

The high performance of general polymer materials such as polyethylene has been the focus of research. Olefin polymerization catalyst is the core of polyolefin polymerization technology. The catalytic efficiency of the traditional Ziegler-Natta catalyst supported on the carrier has been significantly improved, and is called the high-efficiency Ziegler-Natta catalyst, which has enabled the polyolefin industry to develop rapidly. Ultra-fine particles of polyethylene are widely used. Ultra-fine ultra-high molecular weight polyethylene, ultra-fine polyethylene wax, ultra-fine high-density polyethylene and other ultra-fine polyolefin products are used by downstream customers to manufacture injection molding, extrusion, blow molding, etc. product.

In the patent CN102002124, CNPC disclosed a production method for preparing high-density ultra-fine polyethylene powder by slurry method, using an ethoxymagnesium/titanium tetrachloride catalyst with a particle size of 0.2-5.0 polyethylene and a reaction temperature of 75 Under the conditions of ～85℃, reaction pressure of 0.8～1.0MPa and stirring speed of 50～1500RPM, the particle size of the polyethylene powder prepared after the polymerization reaction of the monomer reached 30-80 microns.

In the patents CN106317562A and CN106319667A, the Institute of Chemistry disclosed a series of patents on the preparation of ultra-high molecular weight ultra-fine polyethylene and its application in the field of films and fibers. By controlling the polymerization temperature of ethylene, the purity of the monomer ethylene, adjusting the preparation steps of the catalyst, and introducing a dispersion medium in the polymerization system, a solubilized ultra-high molecular weight ultra-fine particle size polyethylene was synthesized. The traditional magnesium chloride alcoholate used in the catalyst is prepared by titanium tetrachloride dealcoholization. The patent does not propose the average particle size and properties of the prepared catalyst. The average particle size of the resulting polyethylene is 50-80 microns, and the polymer contains a certain amount of high-boiling-point dispersion medium, and the product bulk density is extremely low, only 0.1 -0.3g/mL, although some of the solvent remains in the polymer, which improves the performance of subsequent processing and can be used in the field of separators and fibers, but the very low polyethylene bulk density makes it difficult to collect and transport products.

The polyethylene plant of Liaoyang Petrochemical Company uses the ethoxymagnesium/titanium tetrachloride catalyst system to produce high-density polyethylene. Its catalyst particle size is about 5 microns, and the produced polyethylene product has a particle size of 100-180 microns. Manufacture of injection, extrusion and blow molding products. Another method for preparing ultrafine polyethylene powder is cryogenic pulverization, that is, ordinary polyethylene powder is frozen and then pulverized in advance. This method has a high production cost and increases user burden.

Summary of the invention

In order to overcome the deficiencies of the prior art, one of the problems to be solved by the present invention is to provide a catalyst that can produce polyolefin with ultra-fine particle size, which is used for polymerization reaction, has higher catalytic activity, and has a finer particle size of the resulting polymerization product Ultrafine polyethylene powder with a particle size below 200 microns is obtained.

The second technical problem to be solved by the present invention is to provide a preparation method of the catalyst.

The third technical problem to be solved by the present invention is to provide the application of the catalyst in ethylene polymerization.

The object of the present invention is achieved by the following technical solutions:

A catalyst suitable for producing ultra-fine particle size polyolefin, the catalyst includes: an inorganic carrier obtained by treatment with a surfactant as a first carrier, and an active magnesium chloride generated in situ on the first carrier by a magnesium-containing reagent as a second carrier A carrier, and a catalyst active component supported on the second carrier, the catalyst active component being a Ziegler-Natta catalyst.

Further, the average particle size of the inorganic carrier is 0.01-100 microns, preferably 0.1-30 microns, most preferably 0.5-10 microns, selected from magnesium oxide, silica, alumina, titania, silica- One or more of alumina, silica-magnesia, chain silicate, layered silicate, talc, magnesium hydroxide-magnesium sulfate.

Further, the surfactant has amphiphilicity, and one end of the molecular structure is a hydrophilic group, and the other end is a hydrophobic group, selected from fatty acid methyl ester, methyl alkyl enoate or alkyl dienoic acid methyl ester The number of alkyl carbon chains is 10-24, preferably 12-18. It may have side chains, and the carbon chain may also have other groups such as hydroxyl groups.

Further, the magnesium-containing reagent is selected from Grignard reagent, alkyl magnesium or alkoxy magnesium. The Grignard reagent is C1-10 single Grignard reagent or double Grignard reagent, including alkyl Grignard reagent, alkyl silicon Grignard reagent, aryl Grignard reagent or cycloalkyl Grignard reagent, preferably A Ginger's reagent, methylsilyl Grignard reagent, phenyl Grignard reagent, benzyl Grignard reagent, etc. The alkyl magnesium reagent is a C1-C16 alkyl magnesium reagent, preferably ethyl magnesium, butyl magnesium and the like. The magnesium alkoxide reagent is a C1-C10 magnesium alkoxide reagent, preferably magnesium ethoxide, magnesium butoxide and the like.

Further, the Ziegler-Natta catalyst has the general formula (R'O _m ) _n M'X _4-n , where m = 0 or 1, n is an integer, 0≤n≤4, and R'is C ₁ ~ C ₂₀ alkyl, aryl or cycloalkyl groups; M'is a 4-6 group transition metal, X is a halogen compound; the content of Ziegler-Natta catalyst is 0.1 based on the total amount of the composite catalyst -10wt%, preferably, M'is titanium, vanadium, zirconium or hafnium, X is chlorine, bromine or iodine, the content of the Ziegler-Natta catalyst is 1-6wt% of the total amount of composite catalyst in terms of metal ;

A preparation method of a catalyst suitable for producing ultra-fine particle size polyolefin includes the following steps:

(1) Ultrasonic disperse at least one inorganic carrier from which molecular water has been removed in an organic solvent, then add a surfactant and react at an appropriate temperature to obtain a modified inorganic carrier;

(2) In an organic solvent, add a magnesium-containing reagent to the inorganic carrier suspension obtained in step (1), and react at an appropriate temperature to obtain an inorganic composite carrier containing active magnesium chloride on the surface;

(3) In an organic solvent, at an appropriate temperature, the catalyst active component is impregnated on the inorganic composite carrier obtained in step (2), reacts with the surface of the carrier, so that the catalyst active component is supported on the inorganic composite carrier;

(4) The product obtained in step (3) is filtered and solvent washed to remove excess catalyst active components, and dried to obtain a product.

Further, the organic solvent is selected from C10-C20 long-chain saturated alkane, aromatic hydrocarbon or halogenated aromatic hydrocarbon, or a mixed solvent thereof; step (1) the reaction temperature is 20-200°C, and the reaction time is 0.1-10 hours, The weight ratio of the amount of surfactant to the amount of inorganic carrier is (0.01-50): 1; the weight ratio of the amount of magnesium-containing agent to the amount of inorganic carrier in step (2) is (0.01-50): 1, the reaction temperature is- 50-100℃, the reaction time is 0.1-10 hours; the weight ratio of the amount of the catalyst active component and the inorganic carrier in step (3) is (0.01-50): 1, the reaction temperature is -40-200℃, the reaction time It is 0.1-10 hours, and the stirring speed is 20-800 rpm.

Preferably, the organic solvent includes decane, dodecane, kerosene, dichlorobenzene, trichlorobenzene, trimethylbenzene, xylene, toluene, benzyl chloride, etc., or a mixture of the above solvents, further preferably kerosene, dichloromethane chlorobenzene. The reaction temperature described in step (1) is preferably 50-180°C, and more preferably 80-160°C. The reaction time is 0.5 hours to 5 hours; more preferably 1-3 hours. The weight ratio of the amount of surfactant to the amount of inorganic carrier is preferably (0.1-20): 1, more preferably (0.5-5): 1. The weight ratio of the amount of the magnesium-containing reagent to the amount of the inorganic carrier in step (2) is preferably (0.1-20): 1, more preferably (0.5-5): 1, and the reaction temperature is preferably -40-80 °C, more preferably -20-60 °C. The reaction time is preferably 0.5-5 hours, more preferably 1-3 hours. The weight ratio of the amount of the catalyst component and the inorganic carrier used in step (3) is preferably (0.5-30): 1, more preferably (1-10): 1; the reaction temperature is preferably 60-160°C, more preferably It is 100-140°C; the reaction time is preferably 1 hour to 6 hours, more preferably 2-4 hours; the stirring speed is 150-400 rpm; more preferably 200-300 rpm.

The catalyst is used for olefin polymerization to produce ultra-fine particle size polyethylene, the average particle size of polyethylene is 60-200 microns. The specific method is that, in a single reactor, ethylene, alpha olefin comonomer, catalyst and cocatalyst are added for polymerization reaction, the molar ratio of the alpha hydrocarbon olefin comonomer to ethylene is (0.01-1): 1, The added amount of the catalyst is such that its concentration is (0.01-100) ppm, the added amount of the promoter is so that its concentration is (5-500) ppm, and the promoter is selected from alkyl aluminum compounds, alkyl groups The aluminoxane compound, the halogenated alkyl aluminum compound, the alkyl magnesium compound, the alkyl zinc compound, the alkyl boron compound, or a combination thereof.

The α-olefin comonomer is a C1-C20 α1 olefin, including propylene, 1-butene, 1-pentene, 1-hexene, 1-octene or 1-decene, the α, olefin The molar ratio of comonomer to ethylene is (0.05-0.5): 1, and the amount of the co-catalyst added is such that its concentration is (20-400) ppm.

The polymerization reaction is a conventional olefin polymerization process, including slurry kettle type, slurry loop, or solution polymerization. During the slurry kettle type polymerization, the reaction pressure is 0.1-5MPa and the reaction temperature is 0-120°C. Preferably 40-100°C, most preferably 60-90°C; the reaction pressure of the slurry loop polymerization is 0.5-6MPa, the reaction temperature is 30-150°C, preferably 50-100°C, most preferably 60-90 ℃.

The average particle size of the resulting polyethylene is 10-500 microns, preferably 40-400 microns, and most preferably 60-200 microns. The resulting polyethylene product has an average molecular weight greater than 200,000 and a density of 0.92-0.950 g/cm ³ .

The present invention provides a method for producing ultrafine polyolefin powder. The method includes polymerizing ethylene or a single reactor or two or more reactors in series in the presence of the ultrafine polyolefin catalyst of the present invention under polymerization conditions. By copolymerization with at least one α-olefin, ultrafine polyethylene powder below 200 microns can be obtained.

The key point of the present invention is that in the preparation of the catalyst, the improvement of the carrier is firstly to treat the inorganic carrier with a surface active agent, and secondly to use the magnesium-containing reagent to generate the inorganic carrier containing active magnesium chloride in situ, and then to load the catalyst. In the present invention, fatty acid methyl esters with alkyl carbon chain numbers of 12-18, methyl alkyl enoate or alkyl dienoate are used as surfactants, which have two purposes and functions: one is to improve the dispersion of the inorganic carrier And the uniformity of the reaction with the organomagnesium reagent. The surfactant can chemically react with the surface of the inorganic carrier at a relatively high temperature (the temperature is over 150°C) to produce a long-chain alkyl group on the surface of the inorganic carrier, which helps the dispersion of the inorganic carrier and is beneficial to modification The inorganic carrier reacts with the organomagnesium reagent fully and uniformly; the second is to increase the deactivation resistance temperature of the catalytic component. When the reaction temperature is over 100℃, it will help the catalytic component to fully react with the two inorganic carriers (magnesium chloride and inorganic carrier), the active center will not be deactivated, and the catalytic active center obtained by the reaction will be evenly dispersed on the surface of the carrier. In the polymerization, the catalyst can be uniformly dispersed in the polymerization, reducing the agglomeration of the catalyst particles, and finally preparing ultra-fine particle size polyethylene particles. By loading different active centers, ultra-fine molecular weight ultra-high molecular weight polyethylene can be prepared, which can be used in high-end fields such as lithium battery separators and fiber spinning.

The present invention selects two kinds of composite carriers for three purposes: one is that the catalytic component can be loaded and reacted on the two carriers (magnesium chloride and inorganic oxide) to form more than two active centers, and the resulting polymer product has excellent processing performance . The magnesium chloride carrier can obtain a lower molecular weight product, and the price performance of the polymerization product is proposed; after the inorganic oxide reacts with the catalytic component, an ultra-high molecular weight polymerization product can be obtained to improve the mechanical properties of the polyethylene product; the second is the inorganic oxide and the catalytic component (Such as titanium tetrachloride) fully reacted at high temperature (temperature is over 100℃), forming a new type of active center, reducing chain transfer, and improving the copolymerization ability of the active center, can obtain high molecular weight, high comonomer The content of the polymer product helps to improve the performance of the polymer product; the third is the presence of micro-nano-level inorganic carriers, which helps to improve the mechanical properties of the polymer product and greatly improve the mechanical properties of the product.

Compared with the prior art, the present invention improves the available carrier materials, including inorganic carriers treated with surface-active reagents, and at the same time utilizes the inorganic carrier containing active magnesium chloride generated in situ by the magnesium-containing reagents, while loading the magnesium chloride carrier Highly active catalyst agent, containing surface active agent improves the degree of dispersion of polyolefin particles during the polymerization process, and helps to prepare powder with finer particle size.

BRIEF DESCRIPTION

Figure 1 is an electron micrograph of the polyethylene sample of Example 1a;

Figure 2 is an electron micrograph of the polyethylene sample of Comparative Example 1;

FIG. 3 is the kinetic curves of the catalyst ethylene polymerization of Examples 1a-1b and Comparative Example 1. FIG.

detailed description

The present invention will be described in detail below with reference to the drawings and specific embodiments.

The performance indexes of the polymers in the examples are determined according to the following methods:

ASTM D1238 is used to test the melt index of polyethylene resin (MI2.16, at 2.16kg load, 190℃), flow index (FI, at 21.6kg load, 190℃)

Determination of polymer bulk density: measured in accordance with ASTM-D1895.

The present invention provides a catalyst for producing ultra-fine particle size polyolefin, which includes a catalyst supported on a surface-modified inorganic carrier.

According to one embodiment, the catalyst of the invention comprises:

(1) The inorganic carrier obtained by surfactant treatment is used as the first carrier;

(2) Active magnesium chloride generated in situ by a magnesium-containing reagent as a second carrier;

(3) Multi-site catalyst component supported on the carrier;

The catalyst synthesized by the invention is suitable for producing ultra-fine particle size polyolefin. The micro-nano scale inorganic carrier as the first carrier includes magnesium oxide, silica, alumina, titania, silica-alumina, One or more of silica-magnesia, chain silicate, layered silicate, talc, magnesium hydroxide-magnesium sulfate, etc.; the average particle size of the inorganic carrier is 0.01-100 microns.

Surfactant means that the molecular structure is amphiphilic: one end is a hydrophilic group and the other end is a hydrophobic group. One or more of fatty acid methyl ester, alkyl alkyl enoate and alkyl dienoate are preferred. The molar ratio of the amount of surfactant to the amount of inorganic carrier is (0.01-50): 1.

Magnesium-containing reagents include: Grignard reagents, magnesium alkyls, magnesium alkoxides, etc. The Grignard reagent is C1-10 single Grignard reagent or double Grignard reagent, including alkyl Grignard reagent, alkyl silicon Grignard reagent, aryl Grignard reagent or cycloalkyl Grignard reagent, preferably methyl Grignard reagent Reagents, methylsilyl Grignard reagents, phenyl Grignard reagents, benzyl Grignard reagents, etc.

Ziegler-Natta catalysts have the general formula (R'O _m ) _n M'X _4-n , where m = 0 or 1, 0 ≤ _{n ≤} ₄ , R'is C ₁ ～C ₂₀ alkyl, aromatic Group or cycloalkyl group; M'is a transition metal of Group 4-6, X is a halogen compound; the content of Ziegler-Natta catalyst is 0.5-5wt% of the total amount of composite catalyst in terms of metal.

According to a specific aspect of this embodiment, the following preparation method may be used:

(3) In an organic solvent, at an appropriate temperature, the catalyst component is impregnated on the inorganic composite carrier obtained in step (2), reacts with the surface of the carrier, and the catalyst component is supported on the inorganic composite carrier;

(4) The product obtained in step (3) is filtered and solvent washed to remove excess catalytic components, and dried to obtain a solid catalyst.

Step (1) Perform a program dehydration treatment on the carrier, and select the following carrier, but not limited to this, anhydrous magnesium oxide, silica, alumina, silica-magnesia, alumina-magnesia. The program dehydration treatment method is as follows: under the protection of inert gas (nitrogen or argon), the fluidization treatment is activated. At a temperature between 100°C and 600°C, with a constant temperature of every 100°C for 2 hours, then gradually lower the temperature to room temperature, and store the carrier in nitrogen. Then, the dehydrated and activated inorganic carrier is added to the solvent, ultrasonically dispersed, and then a surfactant is added to react at an appropriate temperature to obtain a modified inorganic carrier.

Step (2) In an organic solvent, including but not limited to toluene, a magnesium-containing reagent is added to the inorganic carrier suspension obtained in the above step. The magnesium-containing reagent includes, but is not limited to, Grignard reagent, alkyl magnesium, alkoxy Magnesium, etc., the reaction temperature is -50 ~ 100 ℃, to obtain nano-inorganic composite carrier containing activated magnesium chloride on the surface.

Step (3) In an organic solvent, including but not limited to toluene, a catalyst component is added to the inorganic composite carrier obtained in the above step for impregnation, and the catalytic component includes, but is not limited to, titanium tetrachloride, titanium trichloride, Zirconium tetrachloride, vanadium tetrachloride, hafnium tetrachloride and their alkoxide compounds react with the surface of the carrier at a reaction temperature between -40 and 200°C, so that the catalyst component is supported on the inorganic composite carrier; the resulting product Filtration and solvent washing remove excess catalyst components, and dry treatment to obtain a solid catalyst.

The cocatalyst used in the polymerization of ethylene of the present invention is selected from alkyl aluminum compounds, alkyl aluminoxane compounds, halogenated alkyl aluminum compounds, alkyl magnesium compounds, alkyl zinc compounds, alkyl boron compounds or combinations thereof, preferably triethyl The aluminum base, monochlorodiethylaluminum, dichloroethylaluminum, triisobutylaluminum, most preferably triethylaluminum or monochlorodiethylaluminum. The concentration of the promoter is generally about 5 to 500 ppm, preferably about 20 to 400 ppm, and most preferably about 40 to 300 ppm (based on the ethylene used).

The present invention provides a method for preparing ultrafine particle size polyolefin powder. The method includes, under polymerization conditions, in the presence of the catalyst of the present invention and corresponding cocatalyst for the polymerization of ethylene alone or with other olefin monomers, such as One or more higher alpha-olefins combined ethylene. Examples are C ₃ -C ₁₀ alpha-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene and 1-octene , 1-butene, 1-pentene, 1-hexene or 4-methyl-1-pentene are preferred and 1-hexene is most preferred.

The polymerization can be carried out using any suitable, conventional olefin polymerization process such as slurry loop, kettle, solution or gas phase polymerization, but it is preferably in a slurry loop reactor or in a kettle reactor, especially a slurry loop Tube reactor. The polymerization can be carried out batchwise, semi-continuously or continuously. With the elimination of catalyst poisons such as moisture, oxygen, carbon monoxide, and acetylene in the polymerization reaction system, a catalytically effective amount of catalyst (composition) is used to carry out the reaction at a temperature and pressure sufficient to initiate the polymerization reaction. A particularly desirable method for producing the polymer of the present invention is in a slurry loop or tank reactor.

The polymerization reaction is a conventional olefin polymerization process, including slurry kettle, slurry loop, or solution polymerization. The reaction pressure during slurry kettle polymerization is 0.1-5 MPa, and the reaction temperature is 0-120°C, preferably 40-100°C. The most preferred is 60-90°C; the reaction pressure during the slurry loop polymerization is 0.5-6MPa, the reaction temperature is 30-150°C, preferably 50-100°C, and most preferably 60-90°C.

In the polymerization method of the present invention, those polymerization conditions generally employed in the art can be used. For example, in slurry loop polymerization, the reaction pressure is 0.5-6 MPa, preferably 1-3 MPa; the reaction temperature is 30-150°C, preferably 60-120°C, more preferably 90-110°C. The kettle polymerization method is generally at a pressure of 0.1 to about 5.0 MPa or higher, preferably a pressure of about 0.5 MPa to about 2.0 MPa and a temperature of 0°C to about 120°C, preferably about 30 to about 110°C, more preferably about 60 to about 100°C Operate at temperature.

With the catalyst according to the present invention, the molecular weight of the polymer can be appropriately controlled in a known manner, such as by using hydrogen. Hydrogen is used as a chain transfer agent. The other reaction conditions are the same. A larger amount of hydrogen results in a lower average molecular weight of the polymer. The hydrogen/ethylene molar ratio used will vary depending on the desired average molecular weight of the polymer, and can be determined by those skilled in the art according to specific circumstances. Without limiting the invention, the amount of hydrogen is generally from about 0.001 to about 2.0 moles of hydrogen per mole of ethylene, preferably 0.01 to 0.5 moles of hydrogen per mole of ethylene.

The polymerization temperature and time can be determined by those skilled in the art based on many factors, such as the type of polymerization process to be used and the type of polymer to be prepared. Since chemical reactions are generally carried out at higher rates at higher temperatures, the polymerization temperature should be high enough to obtain acceptable polymerization rates. Therefore, in general, the polymerization temperature is higher than about 30°C, and more usually higher than about 65°C. On the other hand, the polymerization temperature should not be too high to cause deterioration such as catalyst or polymer. Generally, the polymerization temperature is less than about 200°C, preferably less than about 115°C, and more preferably less than about 100°C.

The polymerization temperature used in the process is determined in part by the density of the polyethylene resin to be produced. More specifically, the melting point of the resin depends on the resin density. The higher the density of the resin, the higher its melting point. Through the ethylene polymerization method of the present invention, the density can be produced in the range of 0.945-0.960g/cm ³ , and the high load flow index (HLMI) is in the range of about 1-200g/10min., preferably in the range of about 2-100g/10min. Of polymers. The polymerization method of the present invention can be an ultrafine particle size polyethylene resin. The polyethylene can have a melt flow ratio of about 40 to about 600, preferably about 50 to about 200, and the product molecular weight distribution MWD is in the range of 3-20.

The following method is used to test the performance of the polyethylene resin produced in the examples:

ASTM D1238 is used to test the melt index of polyethylene resin (MI _2.16 , at 2.16kg load, 190°C), flow index (FI, at 21.6kg load, 190°C) and melt index at 5kg (MI ₅ at 5kg Load, 190°C); due to the low MI _2.16 value and large error, the ratio of FI to MI ₅ is used to represent the melt flow ratio of the product, which can qualitatively describe the change in molecular weight distribution.

The molecular weight distribution (MWD) of the polymer was measured with a Gel Permeation Chromatography (GPC) instrument from Polymer Laboratories.

Example 1:

Preparation of TiCl ₄ /MgCl ₂ /MgO catalyst system;

Example 1a

Preparation of catalyst:

Preparation of the carrier (activation): Under the protection of nitrogen (nitrogen or argon), a small fluidized bed was used to fluidize and activate magnesium oxide. Add 100g of anhydrous nano-magnesium oxide (average particle size 0.5 micron) to perform temperature-controlled activation treatment. The program temperature control step is: at a temperature between 100°C and 400°C, with a constant temperature of every 100°C for 2 hours, and then gradually lower the temperature to room temperature to obtain an activated magnesium oxide carrier S ₀ , which is sealed with nitrogen and stored. Then take 10g of dehydrated activated nano-magnesium oxide S ₀ into toluene, ultrasonic dispersion for 30 minutes, then add 20ml surfactant fatty acid methyl ester (octadecyl carbonate), react at 180 °C for 2 hours, using 100ml xylene Wash three times and dry to obtain the modified inorganic carrier S ₁ .

Under the protection of nitrogen, add 100ml of toluene and at the same time add 5g of modified inorganic carrier. Under stirring, slowly add 10ml (trimethylsilyl) methylmagnesium chloride Grignard reagent at a reaction temperature of 20°C and stir the reaction for 2 hours. It was washed three times with 100 ml of toluene and 100 ml of n-hexane, and dried to obtain nano-inorganic composite carrier S ₂ containing active magnesium chloride on the surface.

Under the protection of nitrogen, add 2 g of S ₂ carrier and 30 ml of titanium tetrachloride to a stirred reaction flask, stir at 140° C. for 2 hours, and rotate at 250 rpm. After the reaction was completed, it was washed 6 times with 100 ml of n-hexane and dried to obtain the catalyst Cat-MgO1.

Slurry polymerization: The reaction device is a 2L steel pressure-resistant water circulation temperature-controlled reaction kettle. The reaction kettle is first treated by vacuum-nitrogen replacement at 95°C for 2-4 hours, and finally filled with nitrogen. Under nitrogen protection, 1L of n-hexane and 50mg are added respectively The catalyst, 2 ml of diethylaluminum monochloride, and then ethylene was replaced 4 times, nitrogen was removed, ethylene was supplemented with a pressure of 1.0 MPa, and polymerization was carried out at 70°C. When the reaction temperature rises, adjust the jacket of the heat exchanger to heat steam or cooling water, and control the reactor temperature at about 70℃. After 2 hours of reaction, the reaction is terminated, the temperature is reduced to room temperature, the material is discharged, dried to obtain a polyethylene product, finally weighed, the bulk density is measured, the particle size distribution is tested, the catalyst activity is calculated and the performance of the polyethylene resin tested according to the above test method Listed in Table 1.

Example 1b:

A composite catalyst was prepared using the same method as Example 1a, except that the surfactant was changed to cis-9-octadecenoic acid methyl ester. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Example 1c:

A composite catalyst was prepared using the same method as in Example 1a, except that the surfactant was changed to 13.16-cis-docosadienoic acid methyl ester. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Example 1d:

A composite catalyst was prepared using the same method as in Example 1a, except that the surfactant was changed to 18-methyl nonacapric methyl carbonate. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Example 1e:

A composite catalyst was prepared using the same method as in Example 1a, except that the magnesium-containing reagent was changed to methylmagnesium chloride Grignard reagent. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Example 1f:

A composite catalyst was prepared using the same method as in Example 1a, except that the magnesium-containing reagent was changed to phenyl magnesium chloride Grignard reagent. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Example 1g:

A composite catalyst was prepared using the same method as Example 1a, except that the magnesium-containing reagent was changed to benzylmagnesium chloride Grignard reagent. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Example 1h:

A composite catalyst was prepared using the same method as in Example 1a, except that the magnesium-containing reagent was changed to butyl magnesium. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Example 1i:

A composite catalyst was prepared using the same method as in Example 1a, except that the magnesium-containing reagent was changed to magnesium ethoxylate. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Comparative example 1:

The catalyst was prepared using the same method as in Example 1a, except that the surfactant was changed to 0 ml. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Comparative example 2:

The catalyst was prepared in the same manner as in Example 1a, except that the surfactant was changed to 0 ml and the magnesium-containing reagent was changed to 0. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

The electron micrographs of the polyethylene samples of Example 1a and Comparative Example 1 are shown in FIGS. 1 and 2. FIG. 1 shows the electron micrographs of the polyethylene sample of Example 1a, and FIG. 2 shows the electron micrographs of the polyethylene sample of Comparative Example 1. . The catalyst ethylene polymerization kinetics curves of Examples 1a-1b and Comparative Example 1 are shown in Figure 3: where curve c represents the catalyst ethylene polymerization kinetics curve in Example 1a, and curve d represents the catalyst ethylene polymerization in Example 1b Kinetic curve diagram, curve e represents the kinetic curve of the catalyst ethylene polymerization of Comparative Example 1.

Table 1 Properties of polyethylene resin

As can be seen from the table, the use of surfactants helps to increase the bulk density of the particles and reduce the average particle size of the resulting polyethylene. At the same time, it was found that the addition of magnesium-containing reagents helps to improve the activity of the catalyst and the bulk density of the product.

Example 2:

Preparation of VCl4/MgCl2/inorganic carrier catalyst system;

Example 2a

Preparation of catalyst:

Preparation of carrier (activation): Under the protection of nitrogen (nitrogen or argon), a small fluidized bed is used to fluidize and activate the inorganic carrier. Add 100g of sheet silicate (preferably but not limited to montmorillonite with an average particle size of 10.0 microns) to perform temperature-controlled activation treatment. The program temperature control step is: at a temperature between 100°C and 600°C, with a constant temperature of every 100°C for 2 hours, and then gradually lower the temperature to room temperature, to obtain an activated magnesium oxide carrier S ₀ , which is sealed with nitrogen and stored. Then take 10g of dehydrated activated montmorillonite S ₀ into dichlorobenzene, ultrasonically disperse for 30 minutes, then add 20ml of surfactant fatty acid methyl ester, react at 180°C for 2 hours, wash three times with 100ml of kerosene, and dry to change Sexual inorganic carrier S ₁ .

Under the protection of nitrogen, add 100ml of dichlorobenzene and at the same time add 5g of modified inorganic carrier. Under stirring, slowly add 10ml (trimethylsilyl) methylmagnesium chloride Grignard reagent at a reaction temperature of 20°C and stir to react 2 Hours, washed with 100 ml of benzyl chloride and 100 ml of n-hexane three times, and dried to obtain an inorganic composite carrier S ₂ containing active magnesium chloride on the surface.

Under the protection of nitrogen, add 2 g of S ₂ carrier and 30 ml of vanadium tetrachloride to a stirred reaction flask, stir at 140° C. for 2 hours, and rotate at 250 rpm. After the reaction was completed, it was washed 6 times with 100 ml of n-hexane and dried to obtain the catalyst Cat-MgO1.

Slurry polymerization: The reaction device is a 2L steel pressure-resistant water circulation temperature-controlled reaction kettle. The reaction kettle is first treated by vacuum-nitrogen replacement at 95°C for 2-4 hours, and finally filled with nitrogen. Under nitrogen protection, add 1L of n-hexane and 50mg The catalyst, 2 ml of triisobutylaluminum, ethylene was replaced 4 times, nitrogen was removed, ethylene was supplemented with a pressure of 1.0 MPa, and polymerization was carried out at 90°C. When the reaction temperature rises, adjust the jacket of the heat exchanger to heat steam or cooling water, and control the reactor temperature at about 90℃. After 2 hours of reaction, the reaction is terminated, the temperature is reduced to room temperature, the material is discharged, dried to obtain a polyethylene product, finally weighed, the bulk density is measured, the particle size distribution is tested, the catalyst activity is calculated and the performance of the polyethylene resin tested according to the above test method Listed in Table 2.

Example 2b:

A composite catalyst was prepared using the same method as in Example 1a, except that the inorganic carrier was changed to talc (average particle size: 5%). The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Example 2c:

The composite catalyst was prepared using the same method as in Example 1a, except that the inorganic carrier was changed to chain silicate (preferably but not limited to attapulgite, and the average particle size of the flat silica gel was changed to 2). The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Example 2d:

A composite catalyst was prepared using the same method as in Example 1a, except that the inorganic carrier was changed to nano-alumina (average particle size 0.1 m 2 oxygen). The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Example 2e:

A composite catalyst was prepared using the same method as in Example 1a, except that the inorganic carrier was changed to magnesium hydroxide-magnesium sulfate (average particle size 3 mg). The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Example 2f:

A composite catalyst was prepared using the same method as in Example 1a, except that the inorganic carrier was changed to a silica-alumina composition (SiO ₂ :Al ₂ O ₃ weight ratio 1:4, average particle diameter 4 average). The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Example 2g:

A composite catalyst was prepared using the same method as in Example 1a, except that the inorganic carrier was changed to a silica-magnesia composition (SiO ₂ :MgO weight ratio 1:3, average particle diameter 0.5 particle diameter). The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Example 2h:

A composite catalyst was prepared using the same method as in Example 1a, except that the inorganic carrier was changed to silica (average particle size 30 dioxins). The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Example 2i:

A composite catalyst was prepared using the same method as in Example 1a, except that the inorganic carrier was changed to nano-titanium dioxide (average particle diameter 1.0 m2). The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 1.

Table 2 Properties of polyethylene resin

It can be seen from Table 2 that by changing different types of inorganic carriers, the activity of the resulting catalyst is also relatively high. Under the action of surfactants and magnesium-containing reagents, the particle size of the resulting polyethylene particles is very fine, both of which are less than 150. Meet the requirements of industrialization.

Example 3:

The catalyst was prepared in the same manner as in Example 1a, except that the catalytic component was changed to zirconium chloride. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 3.

Example 4:

The catalyst was prepared in the same manner as in Example 1a, except that the catalytic component was changed to hafnium chloride. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 3.

Example 5:

The catalyst was prepared in the same manner as in Example 1a, except that the catalytic component was changed to titanium tetrabromide. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 3.

Example 6:

The catalyst was prepared in the same manner as in Example 1a, except that the catalytic component was changed to titanium tetrafluoride. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 3.

Example 6:

The catalyst was prepared in the same manner as in Example 1a, except that the catalytic component was changed to titanium tetraiodide. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 3.

Example 7:

The catalyst was prepared in the same manner as in Example 1a, except that the catalytic component was changed to methoxytitanium trichloride. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 3.

Example 8:

The catalyst was prepared in the same manner as in Example 1a, except that the catalytic component was changed to tri-n-butoxytitanium chloride. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 3.

Example 9:

The catalyst was prepared in the same manner as in Example 1a, except that the catalytic component was changed to diethoxy titanium dichloride. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 3.

Example 10:

The catalyst was prepared in the same manner as in Example 1a, except that the catalytic component was changed to phenoxytitanium chloride. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 3.

Example 11:

The catalyst was prepared using the same method as in Example 1a, except that the catalytic component was changed to tetrachlorobis(tetrahydrofuran) titanium. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 3.

Example 12:

The catalyst was prepared in the same manner as in Example 1a, except that the catalytic component was changed to methyl titanate. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 3.

Example 13:

The catalyst was prepared in the same manner as in Example 1a, except that the catalytic component was changed to pentamethylcyclopentadiene tribenzyloxytitanium. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 3.

Example 14:

The catalyst was prepared in the same manner as in Example 1a, except that the catalytic component was changed to titanium trichloride. The slurry polymerization was carried out according to the same procedure as in Example 1a. The calculated catalytic activity and the properties of the polyethylene resin tested according to the above test method are listed in Table 3.

Table 3 Properties of polyethylene resin

It can be seen from Table 3 that by changing different catalytic components, under the action of surfactants and magnesium-containing reagents, very fine polyethylene particles can be obtained, both of which are less than 150, which meets the requirements of industrialization.

The above description of the embodiments is to facilitate those skilled in the art to understand and use the invention. Those skilled in the art can obviously easily make various modifications to these embodiments, and apply the general principles described here to other embodiments without creative work. Therefore, the present invention is not limited to the above-mentioned embodiments. According to the disclosure of the present invention, those skilled in the art should make improvements and modifications without departing from the scope of the present invention within the protection scope of the present invention.

Claims

A catalyst suitable for producing ultra-fine particle size polyolefins, characterized in that the catalyst includes: an inorganic carrier obtained by treatment with a surfactant as a first carrier, and an activity generated in situ on the first carrier by a magnesium-containing reagent Magnesium chloride serves as a second carrier, and a catalyst active component supported on the second carrier, the catalyst active component is a Ziegler-Natta catalyst.
The catalyst suitable for producing ultra-fine particle size polyolefin according to claim 1, wherein the average particle size of the inorganic carrier is 0.01-100 microns, selected from magnesium oxide, silica, alumina, One or more of titanium dioxide, silica-alumina, silica-magnesia, chain silicate, layered silicate, talc, magnesium hydroxide-magnesium sulfate.
A catalyst suitable for producing ultra-fine particle size polyolefins according to claim 1, characterized in that, in the molecular structure of the surfactant, one end is a hydrophilic group and the other end is a hydrophobic group, selected from fatty acids One or more of methyl ester, methyl alkyl enoate or alkyl dienoate.
The catalyst suitable for producing ultrafine particle polyolefin according to claim 1, characterized in that the magnesium-containing reagent is selected from Grignard reagent, alkyl magnesium or magnesium alkoxide, wherein the Grignard The reagent is a C1-10 single Grignard reagent or a double Grignard reagent, selected from alkyl Grignard reagent, alkyl silicon Grignard reagent, aryl Grignard reagent or cycloalkyl Grignard reagent, the alkyl magnesium reagent It is selected from ethyl magnesium or butyl magnesium, and the alkoxy magnesium reagent is selected from ethoxy magnesium or butoxy magnesium.
The catalyst suitable for producing ultra-fine particle size polyolefin according to claim 1, wherein the Ziegler-Natta catalyst has the general formula (R'O m ) n M'X 4-n , Where m = 0 or 1, n is an integer, 0 ≤ n ≤ 4, R'is a C 1 ~ C 20 alkyl, aryl or cycloalkyl group; M'is a 4-6 group transition metal, X is halogen Compound; The content of Ziegler-Natta catalyst is 0.1-10wt% of the total amount of composite catalyst in terms of metal.
The preparation method of a catalyst suitable for producing ultrafine particle polyolefin according to claim 1, characterized in that it comprises the following steps:

(1) Ultrasonic disperse at least one inorganic carrier from which molecular water has been removed in an organic solvent, then add a surfactant and react at an appropriate temperature to obtain a modified inorganic carrier;

(2) In an organic solvent, add a magnesium-containing reagent to the inorganic carrier suspension obtained in step (1), and react at an appropriate temperature to obtain an inorganic composite carrier containing active magnesium chloride on the surface;

(3) In an organic solvent, at an appropriate temperature, the catalyst active component is impregnated on the inorganic composite carrier obtained in step (2), reacts with the surface of the carrier, so that the catalyst active component is supported on the inorganic composite carrier;

(4) The product obtained in step (3) is filtered and solvent washed to remove excess catalyst active components, and dried to obtain a product.
The preparation method of a catalyst suitable for producing ultrafine particle polyolefin according to claim 6, characterized in that the organic solvent is selected from C10-C20 long-chain saturated alkane, aromatic hydrocarbon or halogenated aromatic hydrocarbon, or their Of mixed solvents;

Step (1) The reaction temperature is 20-240°C, the reaction time is 0.1-10 hours, and the weight ratio of the amount of surfactant to the amount of inorganic carrier is (0.01-50): 1;

Step (2) The weight ratio of the amount of magnesium-containing reagent to the amount of inorganic carrier is (0.01-50): 1, the reaction temperature is -50-100°C, and the reaction time is 0.1-10 hours;

In step (3), the weight ratio of the active component of the catalyst to the amount of the inorganic carrier is (0.01-50): 1, the reaction temperature is -40-200°C, the reaction time is 0.1-10 hours, and the stirring speed is 20-800 rpm.
The preparation method of a catalyst suitable for producing ultrafine particle polyolefin according to claim 7, wherein the organic solvent is selected from decane, dodecane, kerosene, dichlorobenzene, trichlorobenzene , Trimethylbenzene, xylene, toluene, benzyl chloride one or more, preferably kerosene, dichlorobenzene;

The reaction temperature in step (1) is preferably 50-180°C, more preferably 100-160°C; the reaction time is preferably 0.5-5 hours, more preferably 1-3 hours; the amount of surfactant and the amount of inorganic carrier The weight ratio is preferably (0.1-20): 1, more preferably (0.5-5): 1;

The weight ratio of the amount of the organic magnesium reagent to the amount of the inorganic carrier in step (2) is preferably (0.1-20): 1, more preferably (0.5-5): 1, and the reaction temperature is preferably -40-80 ℃, more preferably -20-60 ℃; reaction time is preferably 0.5-5 hours, more preferably 1-3 hours;

The weight ratio of the amount of the catalyst component and the inorganic carrier used in step (3) is preferably (0.5-30): 1, more preferably (1-10): 1; the reaction temperature is preferably 60-160°C, more preferably It is 100-140°C; the reaction time is preferably 1-6 hours, more preferably 2-4 hours; the stirring speed is preferably 150-400 rpm, more preferably 200-300 rpm.
The application of a catalyst suitable for producing ultra-fine particle size polyolefin as claimed in claim 1, characterized in that the catalyst is used for olefin polymerization to produce ultra-fine particle size polyethylene, and the average particle size of the obtained polyethylene is 10- 500 microns, preferably 40-400 microns, most preferably 60-200 microns.
The application of a catalyst suitable for producing ultra-fine particle size polyolefin as claimed in claim 9, characterized in that the specific method is to add ethylene, alpha olefin comonomer, catalyst and cocatalyst in a single reactor During the polymerization reaction, the molar ratio of the α-hydrocarbon olefin comonomer to ethylene is (0.01-1): 1, the amount of the catalyst added is such that its concentration is (0.01-100) ppm, and the addition of the cocatalyst The amount is such that its concentration is (5-500) ppm, and the co-catalyst is selected from alkyl aluminum compounds, alkyl aluminoxane compounds, halogenated alkyl aluminum compounds, alkyl magnesium compounds, alkyl zinc compounds, alkyl boron compounds Or a combination thereof,

The polymerization reaction is a conventional olefin polymerization process, including slurry kettle, slurry loop, or solution polymerization. The reaction pressure during slurry kettle polymerization is 0.1-5 MPa, and the reaction temperature is 0-120°C, preferably 40-100°C. The most preferred is 60-90°C; the reaction pressure during the slurry loop polymerization is 0.5-6MPa, the reaction temperature is 30-150°C, preferably 50-100°C, and most preferably 60-90°C.