CN104558330B - A kind of method that gas-phase polymerization prepares multi-layer core-shell structure polymer particle - Google Patents

Abstract

The invention discloses a method for preparing multi-layer core-shell structure polymer particles by gas phase polymerization. The invention adopts multi-stage addition of inert solid particles of the same type and different particle sizes to prepare multi-layer core-shell structure polymer particles. A mixture of inert solid particles A with a diameter of 100 mm and a catalyst, the catalyst can be effectively adsorbed on the surface of the inert solid particles A, and the polymer grows along the surface of the inert solid particles A; in the middle of the polymerization, add inert solid particles B with a slightly smaller particle size Form a transition layer, the transition layer can be effectively adsorbed on the surface of the polymer particles to reduce the polymerization adhesion and coalescence during the polymerization process; and at the end of the polymerization, add fine particles of inert solid particles C to form a shell structure with inert particles as the main shell, and inert particles The particle-based shell structure can reduce the cold flow adhesion of subsequent polymer particles during storage.

Description

A method for preparing multilayer core-shell polymer particles by gas phase polymerization

technical field

The invention relates to the field of preparation of low glass transition temperature olefin polymer particles, in particular to a method for preparing multilayer core-shell structure polymer particles by gas phase polymerization.

Background technique

Polybutadiene and polyisoprene are widely used in automotive tires, aerospace and other fields, and are produced by solution polymerization. In the solution polymerization process, a large amount of inert solvents such as n-hexane and cyclohexane are used, and an average of about four tons of solvent is needed to produce one ton of rubber. During the production process, the solvent needs to be separated by steam stripping, and the polymerization system The catalyst is extremely sensitive to water and oxygen, and solvent refining is required in the subsequent solvent treatment process. Therefore, solution polymerization has problems such as high energy consumption, high pollution, and complicated post-treatment.

The gas-phase polymerization process is a solvent-free, low-energy-consumption, and relatively simple, green and environmentally friendly process for preparing polymer particles. The gas-phase process is mostly used in the production of polyethylene and polypropylene with high melting points. For polybutadiene or polyisoprene with a low glass transition temperature, the gas-phase polymerization process is prone to adhesion and wall hanging to form large polymers. hinder the implementation of normal production. Therefore, in the polymerization process, it is necessary to add inert solid particles (such as carbon black, silicon dioxide, etc.) as a dispersant to reduce the adhesion and wall hanging of polymer particles. The granular material is used in the gas phase polymerization of butadiene. Chinese invention patent applications 201210063647.4 and 201310063648.9 also disclose gas-phase polymerization of diolefins using inorganic nanoparticles as catalyst supports. Chinese invention patent application 201310384055.2 discloses that the compound inert solid particle system is applied to the gas phase polymerization of butadiene in the supported catalyst system, and polybutadiene with good shape is obtained by compounding and using nano-scale and micro-scale inorganic solid particles particle. Although the addition of inert granular materials has the ability to reduce the adhesion of polymer particles in the reaction system, due to the continuous generation of polymers during the polymerization process, the particle size of the polymers continues to increase, and the inert granular materials added in the early stage are embedded by the polymer and lost. The ability to slow down the adhesion of polymer particles requires the use of a large amount of inert granular materials, resulting in the mass fraction of inert granular materials in the polymer usually exceeding 40%. Excessively high content of inert granular materials limits the use range and material properties of polymer products . In addition, the shape of the polymer particles obtained by the above method is relatively stable at the initial stage of storage, but as time goes by and the temperature changes, the cold flow of the polymer will still cause the polymer to stick during the storage process, which will affect the subsequent processing.

The polymer particles with multi-layer core-shell structure are prepared by adding inert particle materials in multiple stages, and the synergistic use of inert particle materials with different particle sizes can effectively reduce the use of inert particles, and at the same time effectively reduce the occurrence of polymer particles during storage. Adhesion.

Contents of the invention

The purpose of the present invention is to overcome the problems of high pollution, high energy consumption and high cost of traditional solution polymerization, and provide a method for preparing multilayer core-shell polymer particles by gas phase polymerization.

The purpose of the present invention is achieved through the following technical solutions: a method for preparing multilayer core-shell structure polymer particles by gas phase polymerization, the multilayer core-shell structure polymer is composed of three parts, which are respectively based on inert granular materials Main shell structure, intermediate transition layer and polymer-based core structure; in the core structure, the mass fraction of inert granular material A in the core structure is 1-25%, and inert granular material B in the transition layer accounts for the mass of the transition layer The fraction is 25-50%, the mass fraction of the inert granular material C accounting for the shell structure in the shell structure is 50-100%, and the inert granular materials A, B, and C are solid particles of the same material and different particle sizes; the method includes the following steps :

(1) Continuously add the reaction monomers into the reactor, keep the pressure of the polymerization section at 0.01-5MPa, and the temperature of the polymerization section at 0-150 ^o C;

(2) The catalyst is mixed with the inert granular material A and then continuously added to the bottom of the polymerization section of the reactor. The average particle diameter of the inert granular material A used is 200 nanometers to 200 microns, and the ratio of the rare earth catalyst and the inert granular material A is The mass ratio is 0.05～5:10;

(3) The inert granular material B is continuously added to the middle part of the polymerization section of the reactor, the average particle diameter of the inert granular material B is 100 nanometers to 100 microns, and the mass ratio of the inert granular material B to the inert granular material A is: 0.1～1:1;

(4) The inert granular material C is continuously added to the upper part of the polymerization section of the reactor, the average particle diameter of the inert granular material C is 20 nanometers to 50 microns, and the mass ratio of the inert granular material C to the inert granular material A is: 0.5～5:1;

(5) The polymer particles with core-shell structure obtained by polymerization are continuously discharged from the reactor, and the mass ratio of inert granular materials in the polymer particles is less than 35%.

Further, the shell of the multilayer core-shell polymer particle has a thickness of 2 to 20% of the particle diameter; the transition layer of the multilayer core-shell polymer particle has a thickness of 2% to 20% of the particle diameter. 10-50% of that.

Further, the particle diameter of the multilayer core-shell polymer particles is 50 microns to 5 mm.

Further, the monomer is selected from butadiene, isoprene, butene and isobutene.

Further, the inert granular material is obtained by mixing one or more of inorganic solid particles and organic solid particles in any proportion; the inorganic solid particles are selected from carbon black, silicon dioxide, calcium carbonate, aluminum oxide, One of clay and talc; organic solid particles selected from one of polyethylene, polypropylene, polystyrene and polyvinyl chloride.

Further, the catalyst is a multi-component catalyst system with a rare earth element as the core, containing a rare earth element compound, a cocatalyst and an activator; the quality of the rare earth element compound, cocatalyst and activator The ratio is 1:10～20:0.2～2.

Further, the rare earth element compound is composed of one or more compounds of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu according to any formula The compound is obtained by mixing; the compound includes trichloride, naphthenate, neodecanoate, phosphonate, octanoate of rare earth elements.

Further, the cocatalyst is composed of triethylaluminum, diisobutylaluminum hydride, triisobutylaluminum, trihexylaluminum, trimethylaluminoxane, modified methylaluminoxane, trimethylaluminum, It is obtained by mixing one or more of dialkylaluminum hydrides and trialkylaluminums in any proportion;

Further, the activator is a halogen compound, and the halogen compound is an alkylaluminum chloride, benzyl chloride or 1,2-dibromoethane with an alkyl group having 1 to 4 carbon atoms.

The beneficial effect of the present invention is that the present invention prepares polymer particles with a multilayer core-shell structure by adding the same type of inert solid particles with different particle sizes in multiple stages. In the initial stage of polymerization, add large particle size inert solid particle A and catalyst mixture, the catalyst can be effectively adsorbed on the surface of inert solid particle A, and the polymer grows along the surface of inert solid particle A; in the middle stage of polymerization, add a slightly smaller particle size The inert solid particles B form a transition layer, and the transition layer can be effectively adsorbed on the surface of the polymer particles to reduce the polymerization adhesion and coalescence during the polymerization process; and at the end of the polymerization, the inert solid particles C with fine particles are added to form an inert particle-based Shell structure, the shell structure mainly composed of inert particles can reduce the cold flow adhesion of subsequent polymer particles during storage. Therefore, the present invention effectively produces and prepares polymer particles with a multi-layer core-shell structure, and adopts the method of adding inert solid particles of the same type and different particle sizes in multiple stages to effectively reduce the amount of inert solid particles used, and make the polymer particles at room temperature The shape of the lower particles is stable, and there is no cold flow and viscous flow phenomenon or the phenomenon is not obvious.

Description of drawings

Fig. 1 is selected reactor schematic diagram;

Fig. 2 is a schematic diagram of a multilayer core-shell structure polymer;

In the figure, the polymerization section 1 of the reactor, the bottom entrance of the polymerization section 2, the storage tank 3, the middle entrance of the polymerization section 4, the storage tank 5, the upper entrance of the polymerization section 6, the storage tank 7, the polymer-based core structure 8, The transition layer 9 in the middle, and the shell structure 10 mainly composed of inert granular materials.

detailed description

The present invention is further illustrated below by specific examples:

Example 1

Polybutadiene particles with multilayer core-shell structure were prepared by batch method, using a 2L frame-type stirred tank, the polymerization temperature was 70 ^o C, the reaction pressure was 0.2MPa, the butadiene pressure was 0.2MPa, and the polymerization time was 1 hour .

Catalyst pretreatment: Weigh 0.252g neodymium neodecanoate, 2.38g diisobutylaluminum hydride, 0.168g ethylaluminum sesquichloride, add 10ml cyclohexane, and react at 60 ^o C for 1 hour.

The catalyst after the pretreatment is mixed with 80g of inert granular material A and utilized nitrogen to join in the 2L reactor, then close the vacuum valve after the reactor is evacuated to a vacuum state, open the butadiene gas feed valve and feed the butadiene gas, Keep the pressure of the reaction device at 0.2MPa, and the polymerization temperature is 70 ^o C; add 8g of inert granular material B 10 minutes after the start of polymerization, and the inert granular material B is brought into the reactor by butadiene gas; 30 minutes after the start of polymerization Add 40g of inert granular material C afterward, and the inert granular material C is brought into the reactor by butadiene gas; wherein the inert granular material A is silicon dioxide with a particle diameter of 70 microns, and the inert granular material B has a particle diameter of 30 microns. Micron silicon dioxide, the inert particle material C is silicon dioxide with a particle diameter of 50 nanometers. The polymerization obtained 477.9 g polybutadiene particles with good morphology and multilayer core-shell structure.

The polymer particle diameter of the multilayer core-shell structure is 512 microns, the number average molecular weight of the polymer is 3.2X 10 ⁵ g/mol, and the PDI is 3.80. The shape of polybutadiene particles did not change significantly after being placed in an oven at 40C for 2 weeks.

As shown in Figure 2, the multilayer core-shell structure polymer is composed of three parts, which are the shell structure 10 mainly composed of inert granular materials, the intermediate transition layer 9 and the core structure 8 mainly composed of polymers; among them, The mass fraction of inert granular material A in the core structure is 13%, the mass fraction of inert granular material B in the transition layer is 38%, and the mass fraction of inert granular material C in the shell structure is 79%.

Comparative example 1

Adopt the inert granular material A of catalyzer 0.35g and 128g as example 1 and add in the 2L reactor at one time, wherein inert granular material A is the silicon dioxide that particle diameter is 70 microns, closes after the reactor is evacuated again Vacuum valve, open the butadiene gas feed valve to feed butadiene gas, keep the pressure of the reaction device at 0.2 MPa, the polymerization temperature at 70 ^o C, and the polymerization time for 1 hour. Polymerization obtained 320.5 g of agglomerate polymer, and the polymer was conglutinated into agglomerates with obvious wall-hanging phenomenon.

Comparative example 2

Adopt as example 1 catalyst 0.37g and 80g inert granular material A, 8g inert granular material B, 40g inert granular material C one-time join in the 2L reactor, wherein inert granular material A is the silicon dioxide that particle diameter is 70 microns , the inert granular material B is silicon dioxide with a particle diameter of 30 microns, and the inert granular material C is silicon dioxide with a particle diameter of 50 nanometers. After the reactor was evacuated to a vacuum state, the vacuum valve was closed, the butadiene gas feed valve was opened to feed butadiene gas, the pressure of the reaction device was kept at 0.2 MPa, the polymerization temperature was 70 ^o C, and the polymerization time was 1 hour. The polymerization yielded 370.8 g of polymerized butadiene particles. After the polybutadiene particles were placed in an oven at 40C for 1 day, the particles were obviously stuck.

It can be seen that polymer particles with good shape cannot be obtained by using only one type of inert granular material and one-time feeding method, and the obtained polymer particles will re-adhere to form agglomerates under the action of cold flow.

Example 2

Polybutadiene particles with multilayer core-shell structure were prepared by batch method, using a 2L frame-type stirred tank, the polymerization temperature was 50 ^o C, the reaction pressure was 0.2MPa, the butadiene pressure was 0.2MPa, and the polymerization time was 1 hour .

Catalyst pretreatment: Weigh 0.258g neodymium naphthenate, 2.47g triisobutylaluminum, 0.173g ethylaluminum sesquichloride, add 10ml cyclohexane, and react at 50 ^o C for 1 hour.

The catalyst after the pretreatment is mixed with 70g of inert granular material A and utilized nitrogen to join in the 2L reactor, then close the vacuum valve after the reactor is evacuated to a vacuum state, open the butadiene gas feed valve and feed the butadiene gas, Keep the pressure of the reaction device at 0.2MPa, and the polymerization temperature is 50 ^o C; 40g of inert granular material B is added 10 minutes after the start of polymerization, and the inert granular material B is brought into the reactor by butadiene gas; 30 minutes after the start of polymerization Add 35g of inert granular material C afterward, and the inert granular material C is brought into the reactor by butadiene gas; wherein the inert granular material A is silicon dioxide with a particle diameter of 150 microns, and the inert granular material B has a particle diameter of 30 microns Micron silicon dioxide, the inert particle material C is silicon dioxide with a particle diameter of 50 nanometers. Polymerization obtained 440.1 g of polybutadiene particles with a multilayer core-shell structure in good shape.

The polymer particle diameter of the multilayer core-shell structure is 2.15 mm, the number average molecular weight of the polymer is 4.3X 10 ⁵ g/mol, and the PDI is 3.74. The shape of polybutadiene particles did not change significantly after being placed in an oven at 30C for 2 weeks.

Example 3

The polybutadiene particles with multi-layer core-shell structure were prepared by a batch method, using a 2L frame-type stirred tank, the polymerization temperature was 10 ^o C, the reaction pressure was 0.1MPa, the butadiene pressure was 0.1MPa, and the polymerization time was 2 hours .

Catalyst pretreatment was the same as in Example 1. Mix 5.03g of pretreated catalyst with 10g of inert granular material A and add nitrogen into a 2L reactor, then pump the reactor to a vacuum state and close the vacuum valve, open the butadiene gas feed valve to feed butadiene Gas, keep the pressure of the reaction device at 0.1MPa, and the polymerization temperature is 10 ^o C; 2g of inert granular material B is added 30 minutes after the polymerization starts, and the inert granular material B is brought into the reactor by butadiene gas; at the beginning of polymerization Add 30g of inert granular material C after 70 minutes, and the inert granular material C is brought into the reactor by butadiene gas; wherein the inert granular material A is silicon dioxide with a particle size of 10 microns, and the inert granular material B is the particle size of is 0.5 micron silicon dioxide, and the inert particle material C is silicon dioxide with a particle size of 30 nanometers. The polymerization obtained 189.7 g of polybutadiene particles with a multilayer core-shell structure in good shape.

The polymer particle diameter of the multilayer core-shell structure is 113 microns, the number average molecular weight of the polymer is 3.8X 10 ⁵ g/mol, and the PDI is 2.89.

Example 4

Polybutadiene particles with multilayer core-shell structure were prepared by batch method, using a 2L frame-type stirred tank, the polymerization temperature was 50 ^o C, the reaction pressure was 0.2MPa, the butadiene pressure was 0.2MPa, and the polymerization time was 1 hour .

Catalyst pretreatment: Weigh 0.451g lanthanum neodecanoate, 4.33g compound of diisobutylaluminum hydride and triisobutylaluminum (mass ratio 2:1), 0.475g PhCH ₂ Cl, add 10ml cyclohexane alkanes at 60 ^o C for 1 hour.

The pretreated catalyst is mixed with 30g of inert granular material A and added to a 2L reactor with nitrogen, then the reactor is evacuated to a vacuum state and then the vacuum valve is closed, and the butadiene gas feed valve is opened to feed the butadiene gas. Keep the pressure of the reaction device at 0.2MPa, and the polymerization temperature at 50 ^o C; add 5g of inert granular material B 20 minutes after the start of polymerization, and the inert granular material B is brought into the reactor by butadiene gas; 40 minutes after the start of polymerization Add 15g of inert granular material C afterward, and the inert granular material C is brought into the reactor by butadiene gas; wherein the inert granular material A is silicon dioxide with a particle diameter of 30 microns, and the inert granular material B is a particle diameter of 10 microns. Micron silicon dioxide, the inert particle material C is silicon dioxide with a particle size of 0.5 micron. Polymerization obtained 395.4 g of polybutadiene particles with multilayer core-shell structure in good shape.

The polymer particle diameter of the multilayer core-shell structure is 1.31 mm, the number average molecular weight of the polymer is 3.5X 10 ⁵ g/mol, and the PDI is 4.31.

Example 5

Polybutadiene particles with multilayer core-shell structure were prepared by batch method, using a 2L frame-type stirred tank, the polymerization temperature was 70 ^o C, the reaction pressure was 0.2MPa, the butadiene pressure was 0.2MPa, and the polymerization time was 1 hour .

Catalyst pretreatment is the same as example 1. Mix 3.43g of pretreated catalyst with 10g of inert granular material A and add nitrogen into a 2L reactor, then pump the reactor to a vacuum state and close the vacuum valve, open the butadiene gas feed valve to feed in butadiene Gas, keep the pressure of the reaction device at 0.2MPa, and the polymerization temperature is 70 ^o C; 10g of inert granular material B is added after 10 minutes of polymerization, and the inert granular material B is brought into the reactor by butadiene gas; at the beginning of polymerization Add 40g of inert granular material C after 20 minutes, and the inert granular material C is brought into the reactor by butadiene gas; wherein the inert granular material A is silicon dioxide with a particle size of 0.5 microns, and the inert granular material B is the particle size is 0.1 micron silicon dioxide, and the inert particle material C is silicon dioxide with a particle size of 50 nanometers. The polymerization obtained 243.7 g polybutadiene particles with multi-layer core-shell structure in good shape.

The polymer particle diameter of the multilayer core-shell structure is 73.4 microns, the number average molecular weight of the polymer is 2.9X 10 ⁵ g/mol, and the PDI is 3.01.

Example 6

Polybutadiene particles with multilayer core-shell structure were prepared by batch method, using a 2L frame-type stirred tank, the polymerization temperature was 70 ^o C, the reaction pressure was 0.2MPa, the butadiene pressure was 0.2MPa, and the polymerization time was 1 hour .

Catalyst pretreatment is the same as example 1. Mix 3.60g of pretreated catalyst with 15g of inert granular material A and add nitrogen into a 2L reactor, then pump the reactor to a vacuum state and close the vacuum valve, open the butadiene gas feed valve to feed butadiene Gas, keep the pressure of the reaction device at 0.2MPa, and the polymerization temperature is 70 ^o C; 10g of inert granular material B is added 15 minutes after the polymerization starts, and the inert granular material B is brought into the reactor by butadiene gas; at the beginning of polymerization Add 40g of inert granular material C after 30 minutes, and the inert granular material C is brought into the reactor by butadiene gas; wherein the inert granular material A is polystyrene with a particle diameter of 40 microns, and the inert granular material B is a particle diameter of 25 micron polystyrene, inert particle material C is 8 micron polystyrene. Polymerization obtained 403.8 g polybutadiene particles with multi-layer core-shell structure in good shape.

The polymer particle diameter of the multilayer core-shell structure is 401 microns, the number average molecular weight of the polymer is 2.8X 10 ⁵ g/mol, and the PDI is 2.79.

Example 7

Polybutadiene particles with multilayer core-shell structure were prepared by batch method, using a 2L frame-type stirred tank, the polymerization temperature was 70 ^o C, the reaction pressure was 0.1MPa, the butadiene pressure was 0.1MPa, and the polymerization time was 1 hour .

Catalyst pretreatment is the same as example 1. Mix 3.67g of pretreated catalyst with 20g of inert granular material A and add nitrogen into a 2L reactor, then pump the reactor to a vacuum state and close the vacuum valve, open the butadiene gas feed valve to feed butadiene Gas, keep the pressure of the reaction device at 0.1MPa, and the polymerization temperature is 70 ^o C; add 10g of inert granular material B 10 minutes after the start of polymerization, and the inert granular material B is brought into the reactor by butadiene gas; Add 30g inert granular material C after 20 minutes, and inert granular material C is brought in the reactor by butadiene gas; Wherein inert granular material A is the carbon black that particle diameter is 40 microns, and inert granular material B is that particle diameter is 15 micron carbon black, the inert particulate material C is carbon black with a particle size of 1 micron. Polymerization obtained 460.8 g polybutadiene particles with good morphology and multilayer core-shell structure.

The polymer particle diameter of the multilayer core-shell structure is 734 microns, the number average molecular weight of the polymer is 3.5X 10 ⁵ g/mol, and the PDI is 3.34.

Example 8

Polybutadiene particles with multilayer core-shell structure were prepared by batch method, using a 2L frame-type stirred tank, the polymerization temperature was 70 ^o C, the reaction pressure was 0.1MPa, the butadiene pressure was 0.1MPa, and the polymerization time was 1 hour .

Catalyst pretreatment is the same as example 1. Mix 3.54g of pretreated catalyst with 20g of inert granular material A and add nitrogen into a 2L reactor, then pump the reactor to a vacuum state and close the vacuum valve, open the butadiene gas feed valve to feed in butadiene Gas, keep the pressure of the reaction device at 0.1MPa, and the polymerization temperature is 70 ^o C; add 10g of inert granular material B 10 minutes after the start of polymerization, and the inert granular material B is brought into the reactor by butadiene gas; Add 30g of inert granular material C after 20 minutes, and inert granular material C is brought in the reactor by butadiene gas; Wherein the inert granular material A is clay with a particle diameter of 84 microns, and the inert granular material B is a particle diameter of 42 microns micron clay, the inert particulate material C is clay with a particle size of 13 microns. Polymerization obtained 440.8 g polybutadiene particles with good morphology and multilayer core-shell structure.

The polymer particle diameter of the multilayer core-shell structure is 973 microns, the number average molecular weight of the polymer is 4.4X 10 ⁵ g/mol, and the PDI is 4.62.

Example 9

Polyisoprene particles with multi-layer core-shell structure were prepared by a batch method, using a 2L frame-type stirred tank, the polymerization temperature was 120 ^o C, the reaction pressure was 0.1MPa, the isoprene pressure was 0.1MPa, and the polymerization time was 1 hour.

Catalyst pretreatment is the same as example 1. Mix 4.73g of the pretreated catalyst with 40g of inert granular material A and add it into a 2L reactor with nitrogen, then pump the reactor to a vacuum state and close the vacuum valve, open the butadiene gas feed valve to feed the isoprene olefin gas, keep the pressure of the reaction device at 0.1MPa, and the polymerization temperature is 120 ^o C; add 30g of inert granular material B after 10 minutes from the start of polymerization, and the inert granular material B is brought into the reactor by isoprene gas; 120g of inert granular material C was added 20 minutes after the start of the polymerization, and the inert granular material C was brought into the reactor by isoprene gas; wherein the inert granular material A was silicon dioxide with a particle size of 150 microns, and the inert granular material B is silica with a particle size of 70 microns, and the inert particulate material C is silica with a particle size of 10 microns. Polymerization obtained 547.6 g of polyisoprene particles with multilayer core-shell structure in good shape.

The polymer particle diameter of the multilayer core-shell structure is 3.33 mm, the number average molecular weight of the polymer is 2.3X 10 ⁵ g/mol, and the PDI is 3.42. The shape of polyisoprene particles did not change significantly after being placed in an oven at 30C for 2 weeks.

Example 10

Polybutadiene particles with multi-layer core-shell structure were prepared by a continuous method, using a 3L stirred fluidized bed reactor, the polymerization temperature was 70 ^o C, the total pressure of the reaction system was 0.7MPa, and the partial pressure of butadiene gas was 0.56 MPa, nitrogen partial pressure is 0.14MPa.

The catalyst uses neodymium neodecanoate, selects triisobutylaluminum as a cocatalyst, ethylaluminum sesquichloride as an activator, the mass ratio of neodymium neodecanoate to the cocatalyst is 1:15, neodymium neodecanoate and activator The mass ratio of the catalyst system was 1:1.5, and the catalyst system was reacted in n-hexane solvent at 60 ^o C for 1 hour. The catalyst is mixed with the inert granular material A, the mixing mass ratio catalyst: the inert granular material A is 1:5, and the inert granular material A is 70 microns of silica.

As shown in Figure 1, the inert solid particle A and the catalyst are blown into the bottom of the polymerization section by nitrogen from the storage tank 3 through 2; the inert solid particle B is blown into the middle part of the polymerization section from the storage tank 5 by nitrogen through 4; C is blown into the upper part of the polymerization section from the storage tank 7 by nitrogen through 6 .

The intake rate of butadiene monomer under steady state is 3000g/h, and the mixture adding rate of catalyzer and inert granular material A is 24g/h; Add inert granular material B in the polymerization reactor middle section, inert granular material B is 30 Micron silicon dioxide, the addition rate is 10g/h; Add inert granular material C in the upper section of the polymerization reactor, the inert granular material C is 50 nanometer silicon dioxide, and the addition rate is 80g/h; the yield is 376g/h Polybutadiene particles with multi-layer core-shell structure; the amount of butadiene monomer in the exhaust gas is 2614g/h. According to the material balance calculation, 124g/h of butadiene monomer was taken out with the polymer particles of multilayer core-shell structure. The polymerization device is a small stirred fluidized bed reaction device, the reaction residence time is short, and the single-pass conversion rate is low. The unreacted butadiene monomer that has been removed is recirculated and recovered, mixed with a certain amount of supplemented butadiene monomer and re-entered. into the polymerization unit.

The polymer particle diameter of the multilayer core-shell structure is 507 microns, the number average molecular weight of the polymer is 3.3X 10 ⁵ g/mol, and the PDI is 4.01.

Example 11

Polybutadiene particles with multilayer core-shell structure were prepared by a continuous method, using a 3L stirred fluidized bed reactor, the polymerization temperature was 50 ^o C, the total pressure of the reaction system was 1MPa, and the partial pressure of butadiene gas was 0.5MPa , nitrogen partial pressure is 0.5MPa.

The catalyst uses neodymium naphthenate, selects triisobutylaluminum as a cocatalyst, ethylaluminum chloride as an activator, the mass ratio of neodymium naphthenate to the cocatalyst is 1:15, and the mass ratio of neodymium naphthenate to the activator The ratio was 1:2, and the catalyst system was reacted in n-hexane solvent at 50 ^o C for 1 hour. The catalyst is mixed with the inert granular material A, the mixing mass ratio catalyst: the inert granular material A is 1:10, and the inert granular material A is carbon black of 40 microns.

The intake rate of butadiene monomer under steady state is 3000g/h, and the mixture adding rate of catalyzer and inert granular material A is 33g/h; Add inert granular material B in the polymerization reactor middle section, and inert granular material B is 15 Micron carbon black, the addition rate is 15g/h; Add inert granular material C in the upper section of the polymerization reactor, the inert granular material C is carbon black of 1 micron, and the addition rate is 100g/h; the multilayer with a yield of 532g/h Polybutadiene particles with a core-shell structure; the amount of butadiene monomer in the exhaust gas is 2474g/h. According to the material balance calculation, 142g/h of butadiene monomer was taken out with the polymer particles of multilayer core-shell structure. The polymerization device is a small stirred fluidized bed reaction device, the reaction residence time is short, and the single-pass conversion rate is low. The unreacted butadiene monomer that has been removed is recirculated and recovered, mixed with a certain amount of supplemented butadiene monomer and re-entered. into the polymerization unit.

The polymer particle diameter of the multilayer core-shell structure is 448 microns, the number average molecular weight of the polymer is 3.1X 10 ⁵ g/mol, and the PDI is 3.96.

Example 12

Polybutadiene particles with multilayer core-shell structure were prepared by a continuous method, using a 3L stirred fluidized bed reactor, the polymerization temperature was 50 ^o C, the total pressure of the reaction system was 1MPa, and the partial pressure of butadiene gas was 0.5MPa , nitrogen partial pressure is 0.5MPa.

Catalyst selects the catalyst proportioning of example 11 for use. The catalyst is mixed with the inert granular material A, the mixing mass ratio catalyst: the inert granular material A is 1:5, and the inert granular material A is 40 micron polystyrene particles.

Under steady state, the intake rate of butadiene monomer is 3000g/h, and the mixture adding rate of catalyst and inert granular material A is 30g/h; Add inert granular material B in the polymerization reactor middle section, and inert granular material B is 25 Micron polystyrene particles, the rate of addition is 15g/h; Add inert granular material C in the upper section of the polymerization reactor, inert granular material C is polystyrene particles of 8 microns, and the rate of addition is 70g/h; Productive rate is 345g/h h polybutadiene particles with multi-layer core-shell structure; the amount of butadiene monomer in the exhaust gas is 2654g/h. According to the material balance calculation, 116g/h of butadiene monomer was taken out with the polymer particles of multilayer core-shell structure. The polymerization device is a small stirred fluidized bed reaction device, the reaction residence time is short, and the single-pass conversion rate is low. The unreacted butadiene monomer that has been removed is recirculated and recovered, mixed with a certain amount of supplemented butadiene monomer and re-entered. into the polymerization unit.

The polymer particle diameter of the multilayer core-shell structure obtained by polymerization is 410 microns, the number average molecular weight of the polymer is 3.0× ^{10 5} g/mol, and the PDI is 3.83.

Example 13

Polyisoprene particles with a multilayer core-shell structure were prepared by a continuous method, using a 3L stirred fluidized bed reactor, the polymerization temperature was 130 ^o C, the total pressure of the reaction system was 1.5MPa, and the partial pressure of isoprene gas It is 0.8MPa, and the nitrogen partial pressure is 0.7MPa.

The catalyst uses neodymium neodecanoate, selects triisobutylaluminum as a cocatalyst, ethylaluminum sesquichloride as an activator, the mass ratio of neodymium neodecanoate to the cocatalyst is 1:20, neodymium neodecanoate and activator The mass ratio of the catalyst system was 1:1.5, and the catalyst system was reacted in n-hexane solvent at 60 ^o C for 1 hour. The catalyst is mixed with the inert granular material A, the mixing mass ratio catalyst: the inert granular material A is 1:10, and the inert granular material A is 150 micron silica.

The intake rate of isoprene monomer under steady state is 3000g/h, the mixture adding rate of catalyst and inert granular material A is 44g/h; Add inert granular material B in the polymerization reactor middle section, inert granular material B is 30 microns of silicon dioxide, the addition rate is 40g/h; add inert granular material C in the upper section of the polymerization reactor, the inert granular material C is 200 nanometers of silicon dioxide, the addition rate is 160g/h; the yield is 703g/h Polyisoprene particles with a multilayer core-shell structure; the amount of isoprene monomer in the exhaust gas is 2398g/h. According to the material balance calculation, 143g/h of isoprene monomer was taken out with the polymer particles of multi-layer core-shell structure. The polymerization device is a small stirred fluidized bed reaction device, the reaction residence time is short, and the single-pass conversion rate is low. The unreacted isoprene monomer that has been eliminated is recycled and mixed with a certain amount of supplemental isoprene monomer Re-enter the polymerization unit.

The diameter of the polymer particle of the multilayer core-shell structure obtained by polymerization is 1.4 mm, the number average molecular weight of the polymer is 2.5× ^{10 5} g/mol, and the PDI is 3.47.

Example 14

Polybutene particles with multi-layer core-shell structure were prepared by a continuous method, using a 3L stirred fluidized bed reactor, the polymerization temperature was 80 ^o C, the total pressure of the reaction system was 0.7MPa, and the partial pressure of butadiene gas was 0.6MPa , nitrogen partial pressure is 0.1MPa.

Catalyst adopts the catalyst formula of example 10. The catalyst is mixed with the inert granular material A, the mixing mass ratio catalyst: the inert granular material A is 1:4, and the inert granular material A is 70 micron silica.

In the steady state, the intake rate of butene monomer is 3000g/h, and the feed rate of the mixture of catalyst and inert granular material A is 25g/h; inert granular material B is added in the middle section of the polymerization reactor, and the inert granular material B is 30 microns Silica, the addition rate is 20g/h; add inert granular material C in the upper part of the polymerization reactor, the inert granular material C is silicon dioxide of 10 microns, and the addition rate is 80g/h; the yield is more than 415g/h Polybutene particles with a core-shell structure; the amount of butene monomer in the exhaust gas is 2602g/h. According to the material balance calculation, 108g/h of butene monomer was taken out with the polymer particles of multilayer core-shell structure. The polymerization device is a small stirred fluidized bed reaction device, the reaction residence time is short, and the single-pass conversion rate is low. The unreacted butene monomers that have been eliminated are recycled and recovered, mixed with a certain amount of supplemented butene monomers and re-entered into the polymerization. device.

The polymer particle diameter of the multilayer core-shell structure is 733 microns, the number average molecular weight of the polymer is 1.0×10 ⁵ g/mol, and the PDI is 3.21. The shape of polybutene particles did not change significantly after being placed in an oven at 30C for 2 weeks.

The above-mentioned embodiments are used to illustrate the present invention, rather than to limit the present invention. Within the spirit of the present invention and the protection scope of the claims, any modification and change made to the present invention will fall into the protection scope of the present invention.

Claims (9)

1. A method for gas-phase polymerization to prepare multilayer core-shell structure polymer particles, characterized in that, the multilayer core-shell structure polymer is composed of three parts, respectively based on the shell structure of the inert particle material, the middle A transition layer and a polymer-based core structure; wherein, the mass fraction of inert granular material A in the core structure is 1-25%, and the mass fraction of inert granular material B in the transition layer is 25-50% %, the mass fraction of the inert granular material C in the shell structure accounting for the shell structure is 50-100%, and the inert granular materials A, B, and C are solid particles of the same material and different particle sizes; the method includes the following steps: (1) Continuously add the reaction monomers into the reactor, keep the pressure of the polymerization section at 0.01-5MPa, and the temperature of the polymerization section at 0-150 ^o C; (2) The catalyst is mixed with the inert granular material A and then continuously added to the bottom of the polymerization section of the reactor. The average particle diameter of the inert granular material A used is 200 nanometers to 200 microns, and the ratio of the rare earth catalyst and the inert granular material A is The mass ratio is 0.05～5:10; (3) The inert granular material B is continuously added to the middle part of the polymerization section of the reactor, the average particle diameter of the inert granular material B is 100 nanometers to 100 microns, and the mass ratio of the inert granular material B to the inert granular material A is: 0.1～1:1; (4) The inert granular material C is continuously added to the upper part of the polymerization section of the reactor, the average particle diameter of the inert granular material C is 20 nanometers to 50 microns, and the mass ratio of the inert granular material C to the inert granular material A is: 0.5～5:1; (5) The polymer particles with core-shell structure obtained by polymerization are continuously discharged from the reactor, and the mass ratio of inert granular materials in the polymer particles is less than 35%. 2. method according to claim 1 is characterized in that, the shell of described multilayer core-shell structure polymer particle, its thickness is 2～20% of particle particle diameter; Described multilayer core-shell structure polymerization The transition layer of the material particle has a thickness of 10-50% of the particle diameter. 3. The method according to claim 1, characterized in that, the particle diameter of the multi-layer core-shell polymer particles is 50 micrometers to 5 millimeters. 4. The method according to claim 1, wherein the monomer is selected from butadiene, isoprene, butene and isobutene. 5. The method according to claim 1, wherein the inert granular material is obtained by mixing one or more of inorganic solid particles and organic solid particles in any proportion; the inorganic solid particles are selected from carbon One of black, silicon dioxide, calcium carbonate, aluminum oxide, clay, and talc; organic solid particles selected from one of polyethylene, polypropylene, polystyrene, and polyvinyl chloride. 6. method according to claim 1, is characterized in that, described catalyzer is the multi-component catalyst system with rare earth element as core, contains a kind of rare earth element compound, a kind of cocatalyst and a kind of activator; The mass ratio of the rare earth element compound, co-catalyst and activator is 1:10-20:0.2-2. 7. The method according to claim 6, wherein the rare earth element compound is composed of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu One or more of the compounds are mixed in any proportion; the compounds include trichloride, naphthenate, neodecanoate, phosphonate and octanoate of rare earth elements. 8. The method according to claim 6, wherein the cocatalyst is made of triethylaluminum, diisobutylaluminum hydride, triisobutylaluminum, trihexylaluminum, trimethylaluminoxane, modified It is obtained by mixing one or more of methylalumoxane, trimethylaluminum, dialkylaluminum hydride and trialkylaluminum in any proportion. 9. The method according to claim 6, characterized in that, the activator is a halogen compound, and the halogen compound is an alkyl aluminum chloride, benzyl chloride or 1,2 - dibromoethane.