CN106279476B

CN106279476B - Ultra-fine propylene polymerization powder of super high molecular weight and preparation method thereof

Info

Publication number: CN106279476B
Application number: CN201610695070.2A
Authority: CN
Inventors: 李化毅; 李倩; 孙同兵; 朱才镇; 刘瑞刚; 赵宁; 徐坚
Original assignee: Institute of Chemistry CAS
Current assignee: Institute of Chemistry CAS
Priority date: 2016-08-19
Filing date: 2016-08-19
Publication date: 2018-12-14
Anticipated expiration: 2036-08-19
Also published as: CN106279476A

Abstract

本发明涉及一种超高分子量超细粒径丙烯聚合物粉体及其制备方法，所述丙烯聚合物的粘均分子量(Mv)大于1×10⁶，所述丙烯聚合物粉体为球形颗粒，平均粒径为10μm‑200μm，标准差为2μm‑15μm，堆密度为0.1g/mL‑0.4g/mL。所述方法步骤简单、易于控制、重复性高，可以实现工业化。本发明的粉体同时兼具超高分子量和超细的粒径范围，特别适合于加工应用，而且易于实现接枝改性，极大地扩展了超高分子量丙烯聚合物的应用领域和适用范围。The invention relates to a propylene polymer powder with ultra-high molecular weight and ultra-fine particle size and a preparation method thereof. The viscosity-average molecular weight (Mv) of the propylene polymer is greater than 1×10 ⁶ , and the propylene polymer powder is spherical particles , the average particle size is 10μm-200μm, the standard deviation is 2μm-15μm, and the bulk density is 0.1g/mL-0.4g/mL. The method has simple steps, is easy to control, has high repeatability, and can realize industrialization. The powder of the invention has both ultra-high molecular weight and ultra-fine particle size range, is particularly suitable for processing and application, and is easy to realize graft modification, greatly expanding the application field and scope of application of the ultra-high molecular weight propylene polymer.

Description

Ultra-high molecular weight superfine propylene polymer powder and preparation method thereof

Technical Field

The invention belongs to the field of polyolefin high polymer materials, and particularly relates to ultra-high molecular weight ultrafine particle size propylene polymer powder and a preparation method thereof.

Background

The ultra-high molecular weight propylene polymer (UHMWPP) and the ultra-high molecular weight polyethylene (UHMWPE) belong to flexible chain macromolecules, the structure is regular, the crystallization performance is excellent, and compared with the UHMWPP, the UHMWPP also has the advantages of better adhesion, higher use temperature, lower creep deformation and the like. However, since the viscosity of the ultra-high molecular weight polymer in a molten state is extremely high and the melt flow property is extremely poor (the melt flow index thereof is almost zero), it is difficult to process it by a general hot working method. The processing technology of UHMWPE has been developed over decades from the initial compression-sintering molding to various molding methods such as extrusion, blow molding, injection, solution spinning molding, etc., but the processing and application of UHMWPP are slow, on one hand, because the synthesis of ultra-high molecular weight propylene polymers is difficult, and only propylene polymer resins with molecular weight of hundreds of thousands can be obtained under common polymerization conditions, on the other hand, UHMWPP is more difficult to process and mold than UHMWPE.

The development of a new processing method is a solution, and how to prepare the UHMWPP which has more excellent processing performance and is easier to process is a more fundamental and more effective solution, so that the method has a good development prospect.

Disclosure of Invention

The invention aims to provide a preparation method of ultra-high molecular weight and ultra-fine particle size propylene polymer powder.

Another object of the present invention is to provide a powder produced by the above method, which has excellent processability.

In order to achieve the above object, the present invention provides a method for preparing ultra-high molecular weight ultra-fine particle size propylene polymer powder, comprising the steps of:

under the action of a catalyst, propylene or propylene and a comonomer are subjected to polymerization reaction, wherein the polymerization reaction temperature is 30-105 ℃, and the volume fraction of the propylene is more than or equal to 98%;

the catalyst is prepared by a method comprising the following steps:

(a) mixing magnesium halide, an alcohol compound, an auxiliary agent, part of internal electron donor and a solvent to prepare a mixture I;

(b) adding the mixture I into a reactor, preheating to-30 ℃, and dropwise adding a titanium compound; or adding a titanium compound into a reactor, preheating to-30 ℃, and dropwise adding the mixture I;

(c) after the dropwise addition is finished, the reaction system is heated to 90-130 ℃ after 30 minutes-3 hours, and the rest internal electron donor is added for continuous reaction;

(d) filtering liquid in the reaction system, adding the residual titanium compound, and continuing the reaction;

(e) after the reaction is finished, post-treating to obtain the catalyst;

wherein the resulting propylene polymer has a viscosity average molecular weight (Mv) of greater than 1X 10⁶(ii) a The propylene polymer powder is spherical particles, the average particle diameter is 10-200 mu m, the standard deviation is 2-15 mu m, and the bulk density is 0.1-0.4 g/mL.

According to the invention, the particle size distribution of the propylene polymer powder is approximately normal.

According to the invention, the comonomer is C_2-20α -olefins such as one or more of ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, or 1-dodecene preferably the comonomer is one or both of ethylene and 1-butene, the comonomer content being from 0 to 10 mol%, preferably from 0 to 5 mol%.

According to the invention, the polymerization temperature is preferably 40-80 ℃.

According to the invention, the volume fraction of propylene is greater than or equal to 99%, more preferably greater than or equal to 99.8%, still more preferably greater than or equal to 99.9%.

According to the invention, the comonomer (e.g. ethylene or 1-butene) has a carbon monoxide content of less than 5ppm, a carbon dioxide content of less than 15ppm and a conjugated diene content of less than 10 ppm.

The invention also provides the ultra-high molecular weight ultrafine grain diameter propylene polymer powder prepared by the preparation method, wherein the viscosity average molecular weight (Mv) of the propylene polymer is more than 1 x 10⁶(ii) a The propylene polymer powder is spherical particles, the average particle diameter is 10-200 mu m, the standard deviation is 2-15 mu m, and the bulk density is 0.1-0.4 g/mL. Preferably, the particle size distribution of the propylene polymer powder is approximately normal.

According to the invention, the propylene polymer is a propylene homopolymer or a propylene copolymer, the comonomer in the propylene copolymer being C_2-20α -olefins such as one or more of ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, or 1-dodecene preferably the comonomer is one or both of ethylene and 1-butene, the comonomer content being from 0 to 10 mol%, preferably from 0 to 5 mol%.

According to the invention, the propylene polymer has a viscosity average molecular weight (Mv) of 1.5X 10 or more⁶Preferably 1.5X 10⁶～4.0×10⁶(ii) a The molecular weight distribution Mw/Mn of the propylene polymer is 2-15, preferably 3-10, and further preferably 4-8.

According to the invention, the propylene polymer powder preferably has an average particle size of 20 μm to 180 μm, more preferably 30 μm to 150 μm; the standard deviation is preferably 5 μm to 15 μm, more preferably 6 μm to 12 μm, and further preferably 8 μm to 10 μm; the bulk density of the powder is preferably 0.15g/mL-0.35 g/mL.

The invention has the beneficial effects that:

the invention provides a brand new method for preparing ultra-high molecular weight and ultra-fine particle size propylene polymer powder, which synthesizes the ultra-high molecular weight and ultra-fine particle size propylene polymer powder by controlling polymerization temperature, monomer purity and adjusting the preparation steps of a catalyst.

According to the invention, the propylene polymer powder with both ultra-high molecular weight and ultra-fine particle size range is synthesized for the first time, and researches show that the powder with the characteristics is particularly suitable for processing and application, and is easy to realize graft modification, so that the application field and the application range of the ultra-high molecular weight propylene polymer are greatly expanded. Meanwhile, the propylene polymer powder also has the following excellent properties: firstly, the wear resistance is very excellent and is several times higher than the wear resistance index of metals such as common carbon steel, copper and the like; secondly, due to the fact that the molecular weight is ultrahigh, the molecular chain is overlong, and the impact strength of the material is high; thirdly, the chemical resistance of the propylene polymer powder is stronger than that of common polyolefin; finally, the material has a wider range of use temperature, and can keep good toughness and strength at lower or higher temperature.

Detailed Description

[ method for producing catalyst ]

The catalyst employed in the preparation process of the present invention may be prepared by the process disclosed in the invention patent application (application No. 201510271254.1) filed by the applicant, the entire contents of which are incorporated herein by reference.

Specifically, the catalyst used in the preparation method of the present invention is prepared by a method comprising the steps of:

(e) after the reaction is finished, the catalyst is obtained by post-treatment.

In the present invention, said step (b) is replaced by the following step (b'):

(b') preparing a mixture II comprising nanoparticles, a dispersant and a solvent;

adding the mixture I and the mixture II into a reactor to obtain a mixture of the mixture I and the mixture II, preheating to-30 ℃, and dropwise adding a titanium compound; or,

adding a titanium compound into a reactor, preheating to-30 ℃, and dropwise adding the mixture of the mixture I and the mixture II.

In the present invention, said mixture I is preferably prepared as follows: mixing magnesium halide and an alcohol compound in an organic solvent, heating and preserving heat, adding an auxiliary agent and part of internal electron donor, and reacting at a certain temperature to obtain a stable and uniform mixture I. The alcohol compound is selected from C_1-C₁₅Fatty alcohol compound of (2), C₃-C₁₅And C₆-C₁₅The aromatic alcohol compound (b) is preferably one or more selected from methanol, ethanol, ethylene glycol, n-propanol, isopropanol, 1, 3-propanediol, butanol, isobutanol, hexanol, heptanol, n-octanol, isooctanol, nonanol, decanol, sorbitol, cyclohexanol, and benzyl alcohol, and more preferably ethanol, butanol, hexanol, and isooctanol. The internal electron donor is at least one of monoester, diester, monoether and diether compounds, and is more preferably selected from diester or diether. The solvent is at least one of linear alkane with 5-20 carbons, branched alkane with 5-20 carbons, aromatic hydrocarbon with 6-20 carbons or halogenated hydrocarbon thereofAt least one of toluene, chlorobenzene, dichlorobenzene, or decane is preferable. In the invention, the magnesium halide has the function of a carrier in the preparation of the catalyst capable of directly obtaining submicron polyolefin particles, is one of the components of the traditional Ziegler-Natta catalyst, can ensure that the prepared catalyst has proper shape, size and mechanical strength, and simultaneously, the carrier can ensure that the active component is dispersed on the surface of the carrier, thereby obtaining higher specific surface area and improving the catalytic efficiency of the active component per unit mass. In addition, the alcohol compound serves to dissolve the magnesium halide, which is a carrier. In the preparation of the mixture I, the temperature of the obtained mixed solution is preferably 110 ℃ to 130 ℃, more preferably 130 ℃, the incubation time is preferably 1 to 3 hours, more preferably 2 to 3 hours, and the reaction time after addition of the auxiliary agent and the like is 0.5 to 2 hours, more preferably 1 hour. Thus, the magnesium halide is dissolved by the alcohol compound at high temperature to give a mixture I.

In the present invention, said mixture II is preferably prepared as follows: and adding the nano particles, the dispersing agent and the solvent into a reaction vessel, and carrying out ultrasonic treatment to obtain a uniform mixture II. The nano particles are preferably at least one of nano silicon dioxide, nano titanium dioxide, nano zirconium dioxide, nano nickel oxide, nano magnesium chloride or nano carbon spheres, and more preferably are nano silicon dioxide and nano titanium dioxide. The particle size of the nanoparticles is preferably 1 to 80nm, more preferably 10 to 50 nm. The addition mass of the nanoparticles is preferably 0% to 200%, more preferably 0% to 20%, relative to the addition mass of the magnesium halide. The time of the ultrasonic treatment is preferably 2 hours. In the present invention, the nanoparticles are introduced as seeds in order to accelerate the shaping of the support and to reduce the particle size of the catalyst particles; both the dispersing agent and the solvent, including sonication, are intended to aid in the dispersion of the nanoparticles, thus facilitating the function of the seed for each nanoparticle.

In the present invention, in the mixture II in the step (b'), the nanoparticles are selected from at least one of nano silicon dioxide, nano titanium dioxide, nano zirconium dioxide, nano nickel oxide, nano magnesium chloride or nano carbon spheres.

Preferably, the nanoparticles have a particle size of 1 to 80nm, preferably 2 to 60 nm, more preferably 3 to 50 nm.

The addition mass of the nanoparticles is more than 0% and less than or equal to 200% relative to the addition mass of the magnesium halide, and preferably, the addition amount of the nanoparticles ranges from more than 0% to less than or equal to 20%.

In the present invention, in the mixture II in the step (b'), the solvent is at least one selected from linear alkanes having 5 to 20 carbons, branched alkanes having 5 to 20 carbons, aromatic hydrocarbons having 6 to 20 carbons, and halogenated hydrocarbons thereof.

The dispersing agent is selected from titanium tetrachloride, silicon tetrachloride or a mixture of the titanium tetrachloride and the silicon tetrachloride.

In step (a), the mixing is carried out under heating and stirring to obtain a uniform and stable transparent mixture I.

In step (b'), ultrasonic dispersion treatment is performed at the time of deployment.

In the step (b) or (b'), the dropwise addition is carried out slowly.

In step (b) or (b'), the reaction preheating temperature is preferably from-20 ℃ to 30 ℃, more preferably from-20 ℃ to 20 ℃.

The reaction time of step (c) is 1 to 5 hours, preferably 2 to 3 hours.

The reaction of step (d) is continued for a period of 1 to 5 hours, preferably 2 to 3 hours.

The post-treatment in the step (e) can be washing the obtained product by using hexane and then drying; wherein the number of washing may be 1 to 10, preferably 3 to 6.

In the step (a), the magnesium halide is at least one selected from magnesium chloride, magnesium bromide and magnesium iodide.

In the step (a), the auxiliary agent may be a titanate compound.

In step (b) or (b'), the titanium compound has a general formula shown in formula I:

Ti(R)_nX_(4-n)

formula I

Wherein R is C1-C12 branched chain or straight chain alkyl, X is halogen, and n is 0, 1, 2 or 3.

In step (d), preferably, the temperature of the reaction system is raised to 90 to 130 ℃ over 40 minutes to 3 hours, more preferably, the temperature of the reaction system is raised to 100 to 120 ℃ over 40 minutes to 2 hours.

According to the scheme, the preparation method of the Ziegler-Natta catalyst is simple in process and easy for industrial production. In addition, the Ziegler-Natta catalyst prepared by the invention can prepare propylene polymer particles with the average particle size of 10-200 μm, higher sphericity, narrower particle size distribution and low bulk density (0.1-0.4 g/mL) during propylene polymerization. According to research, the catalyst prepared by the invention is used for propylene polymer particles obtained by propylene polymerization, the particle size is reduced by 20-30 times compared with other particles, the particle size distribution is obviously narrowed, and the bulk density can be as low as 0.1 g/mL.

[ method for producing propylene Polymer powder ]

As described above, the present invention provides a method for preparing ultra-high molecular weight ultra-fine particle size propylene polymer powder, comprising the steps of:

the catalyst is prepared by the preparation method of the catalyst.

The present inventors have found, through research, that the particle size of the powder can be controlled well by simply controlling the preparation method of the catalyst, but the molecular weight of the propylene polymer to be prepared is not high, and many attempts have been made by the inventors to increase the molecular weight of the polymer while controlling the particle size.

According to research, the temperature of the polymerization reaction is controlled to be 30-105 ℃, the volume fraction of the propylene is controlled to be more than or equal to 98%, and the ultrahigh molecular weight propylene polymer can be prepared while the particle size is controlled. Further preferably, the temperature of the polymerization reaction is 40-80 ℃. More preferably, the volume fraction of propylene is greater than or equal to 99%; still more preferably, 99.8% or higher; still more preferably, 99.9% or more. For copolymerization, it is advantageous to control the content of carbon monoxide in the comonomer to be less than 5ppm, carbon dioxide to be less than 15ppm and the content of conjugated diene to be less than 10 ppm.

In the present invention, the propylene volume fraction is determined by the standard GB/T3392. The propylene volume fraction is an important indicator of the purity of the propylene monomer.

[ propylene Polymer powder ]

As described above, the powder of the present invention is an ultrahigh molecular weight propylene polymer having a viscosity average molecular weight (Mv) of more than 1X 10⁶The propylene polymer powder is spherical particles, the average particle diameter is 10-200 mu m, the standard deviation is 2-15 mu m, and the bulk density is 0.1-0.4 g/mL. Preferably, the particle size distribution of the propylene polymer powder is approximately normal. The average particle diameter is preferably 20 μm to 180 μm, more preferably 30 μm to 150 μm. The standard deviation is preferably 5 μm to 15 μm, more preferably 6 μm to 12 μm, and further preferably 8 μm to 10 μm. The bulk density is preferably 0.15g/mL to 0.35 g/mL. The propylene polymer with the ultrahigh molecular weight and the particle size and the bulk density is particularly suitable for graft modification, and on one hand, the modification space of the propylene polymer is greatly expanded; on the other hand, in the case of a liquid,the processability of the polymer is remarkably improved, and the polymer is suitable for preparation of products in a wider range; thus, the application field of the polymer is effectively expanded.

Meanwhile, the propylene polymer powder of the present invention also has the following excellent properties: firstly, the wear resistance is very excellent and is several times higher than the wear resistance index of metals such as common carbon steel, copper and the like; secondly, due to the fact that the molecular weight is ultrahigh, the molecular chain is overlong, and the impact strength of the material is high; thirdly, the chemical resistance of the propylene polymer powder is stronger than that of common polyolefin; finally, the material has a wider range of use temperature, and can keep good toughness and strength at lower or higher temperature.

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various other respects, all without departing from the spirit of the present invention.

Example 1 propylene homopolymer and preparation thereof

4.94g of anhydrous magnesium chloride, 18.9g of isooctyl alcohol and 30ml of decane are sequentially added into a reactor fully replaced by high-purity nitrogen, the temperature is raised to 130 ℃ under stirring and maintained for 2 hours, then 2.65g of tetrabutyl titanate and 2.05g of diisobutyl phthalate are added, the reaction is carried out for 1 hour at the temperature of 130 ℃, and finally the mixture is cooled to room temperature to form a uniform transparent solution, namely a mixture I.

200ml of titanium tetrachloride was added to the reaction vessel, stirred and preheated to 0 ℃ and the mixture I was added dropwise to the titanium tetrachloride over about 2 hours. After the dropwise addition, the temperature was raised to 110 ℃ within 2 hours. 1.23g of diisobutylphthalate as an internal electron donor was added. After reacting at this temperature for 2 hours, the reaction liquid was removed, and 200ml of titanium tetrachloride was added again to react for 2 hours. And finally, removing reaction liquid, washing the remaining solid substance with hexane at 60 ℃ for 10 times, and drying to obtain the catalyst.

Bulk polymerization of propylene:

under the protection of high-purity nitrogen, a 5L high-pressure reaction kettle is dried and deaerated, 20mg of the catalyst, 12ml of triethyl aluminum and 3ml of external electron Donor Donor-P are added, 1200g of propylene is then added, wherein the volume fraction of the propylene is 99.9%, the polymerization reaction starts, the system temperature is maintained at 45 ℃, the reaction time is 60 minutes, and the activity and the property of the obtained catalyst are shown in Table 1.

Example 2 propylene-ethylene copolymer and preparation thereof

The catalyst was prepared in the same manner as in example 1.

Propylene-ethylene copolymerization:

under the protection of high-purity nitrogen, a 5L high-pressure reaction kettle is dried and deaerated, 20mg of the catalyst and 12ml of triethyl aluminum and 3ml of external electron Donor Donor-P are added, 1200g of propylene is then added, and 40g of ethylene is introduced, wherein the volume fraction of the propylene is 99.9%, the content of carbon monoxide in ethylene gas is less than 5ppm, the content of carbon dioxide is less than 15ppm, and the content of conjugated diene is less than 10ppm, the polymerization reaction starts, the system temperature is maintained at 75 ℃, the reaction time is 60 minutes, and the activity of the obtained catalyst and the property of the propylene-ethylene copolymer are shown in Table 1.

Example 3 propylene homopolymer and preparation thereof

The catalyst was prepared in the same manner as in example 1.

Bulk polymerization of propylene:

under the protection of high-purity nitrogen, a 5L high-pressure reaction kettle is dried and deaerated, 20mg of the catalyst, 12ml of triethyl aluminum and 3ml of external electron Donor Donor-P are added, 1200g of propylene is then added, wherein the volume fraction of the propylene is 99.9%, the polymerization reaction starts, the system temperature is maintained at 55 ℃, the reaction time is 60 minutes, and the activity and the property of the obtained catalyst are shown in Table 1.

Example 4 propylene homopolymer and preparation thereof

The catalyst was prepared in the same manner as in example 1.

Bulk polymerization of propylene:

under the protection of high-purity nitrogen, a 5L high-pressure reaction kettle is dried and deaerated, 20mg of the catalyst, 12ml of triethyl aluminum and 3ml of external electron Donor Donor-P are added, 1200g of propylene is then added, wherein the volume fraction of the propylene is 99.9%, the polymerization reaction starts, the system temperature is maintained at 65 ℃, the reaction time is 60 minutes, and the activity and the property of the obtained catalyst are shown in Table 1.

TABLE 1 catalytic Activity of Ziegler-Natta catalysts prepared according to the examples of the present invention and Properties of the propylene polymers produced

The propylene polymers of examples 1-4 were further tested for other properties and found to be: (1) the propylene polymers of examples 1-4 all had several times higher abrasion resistance indices than those of ordinary carbon steel or copper; (2) the impact strength of the propylene polymers of examples 1-4 is 2-5 times that of the conventional polypropylene; (3) the propylene polymer powders of examples 1-4 have a higher resistance to chemical attack than the conventional polyolefins; (4) the propylene polymer powders of examples 1-4 have a wide range of service temperatures and retain good toughness and strength at either lower temperatures (e.g., 30 ℃ C.) or higher temperatures (e.g., 130 ℃ C.).

Comparative examples 1 to 2

A similar procedure to example 1 was followed, except that the polymerization temperature and the purity of the monomers were different. The results are shown in Table 2.

TABLE 2 Properties of the propylene polymers of comparative examples 1-2

Claims

1. a preparation method of ultrahigh molecular weight ultrafine particle diameter propylene polymer powder, is characterized in that, described method comprises the following steps:

Under the action of a catalyst, propylene or propylene and a comonomer undergo a polymerization reaction, wherein the temperature of the polymerization reaction is 40-80°C, and the volume fraction of the propylene is greater than or equal to 99%;

The catalyst is prepared by a method comprising the following steps:

(a) Mix magnesium halide and alcohol compound in an organic solvent, heat up and keep warm, add additives and part of the internal electron donor, and obtain mixture I after reacting at a certain temperature;

(b) Add the above-mentioned mixture I into the reactor, preheat to -30°C to 30°C, and add the titanium compound dropwise; or, add the titanium compound to the reactor, preheat to -30°C to 30°C, add dropwise the above-mentioned mixture I;

(c) After the dropwise addition is completed, the temperature of the reaction system is raised to 90° C. to 130° C. after 30 minutes to 3 hours, and the remaining internal electron donor is added to continue the reaction;

(d) filter out the liquid in the reaction system, add the titanium compound, and continue the reaction;

(e) After the reaction is completed, post-processing obtains the catalyst;

The viscosity-average molecular weight (Mv) of the prepared propylene polymer is greater than 1×10 ⁶ ; the propylene polymer powder is a spherical particle with an average particle diameter of 10 μm-200 μm, a standard deviation of 2 μm-15 μm, and a bulk density of 0.1 g/mL-0.4g/mL.

2. The preparation method according to claim 1, characterized in that the particle size distribution of the propylene polymer powder is close to a normal distribution.

3. preparation method according to claim 1, is characterized in that, described comonomer is ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1 - one or more of nonene, 1-decene, 1-undecene or 1-dodecene.

4. The preparation method according to claim 3, characterized in that, the comonomer is one or both of ethylene and 1-butene.

5. The preparation method according to any one of claims 1-4, characterized in that the mole percentage of the comonomer is 0-10 mol%.

6. The preparation method according to claim 5, characterized in that the mole percentage of the comonomer is 0-5 mol%.

7. The preparation method according to any one of claims 1-4, characterized in that the volume fraction of the propylene is greater than or equal to 99.8%.

8. The preparation method according to claim 7, characterized in that the volume fraction of the propylene is greater than or equal to 99.9%.

9. The preparation method according to any one of claims 1-4, characterized in that, in the comonomer, the carbon monoxide content is less than 5 ppm, the carbon dioxide content is less than 15 ppm, and the conjugated diene content is less than 10 ppm.

10. The ultrahigh molecular weight ultrafine particle diameter propylene polymer powder obtained by the preparation method described in any one of claims 1-9, is characterized in that the viscosity-average molecular weight (Mv) of the propylene polymer is greater than 1 ×10 ⁶ ; the propylene polymer powder is a spherical particle with an average particle diameter of 10 μm-200 μm, a standard deviation of 2 μm-15 μm, and a bulk density of 0.1 g/mL-0.4 g/mL.

11. The powder according to claim 10, characterized in that, the viscosity-average molecular weight (Mv) of the propylene polymer is greater than or equal to 1.5×10 ⁶ ; the molecular weight distribution Mw/Mn of the propylene polymer is 2 to 15 .

12 . The powder according to claim 11 , wherein the viscosity average molecular weight (Mv) of the propylene polymer is 1.5×10 ⁶ to 4.0×10 ⁶ .

13. The powder according to claim 11, characterized in that the molecular weight distribution Mw/Mn of the propylene polymer is 3-10.

14. The powder according to claim 13, characterized in that the molecular weight distribution Mw/Mn of the propylene polymer is 4-8.

15. The powder according to claim 10, characterized in that, the average particle diameter of the propylene polymer powder is 20 μm-180 μm; the standard deviation is 5 μm-15 μm.

16. The powder according to claim 15, characterized in that the average particle diameter of the propylene polymer powder is 30 μm-150 μm.

17. The powder according to claim 15, wherein the standard deviation is 6 μm-12 μm.

18. The powder according to claim 17, wherein the standard deviation is 8 μm-10 μm.

19. The powder according to claim 10, characterized in that the bulk density of the powder is 0.15g/mL-0.35g/mL.