CN112745413B

CN112745413B - Preparation method and device of metallocene polypropylene

Info

Publication number: CN112745413B
Application number: CN201911044537.7A
Authority: CN
Inventors: 宋莎; 刘振宇; 曹育才; 朱红平; 蒋文军; 王伟哲; 刘国禹; 谢京燕
Original assignee: China Petroleum and Chemical Corp; Shanghai Research Institute of Chemical Industry SRICI; Xiamen University
Current assignee: China Petroleum and Chemical Corp; Shanghai Research Institute of Chemical Industry SRICI; Xiamen University
Priority date: 2019-10-30
Filing date: 2019-10-30
Publication date: 2023-06-13
Anticipated expiration: 2039-10-30
Also published as: CN112745413A

Abstract

The invention discloses a preparation method and a device of metallocene polypropylene. Wherein the catalyst is a metallocene catalyst obtained by loading a bridged substituted indenyl compound, a cocatalyst and a carrier. The propylene polymerization adopts a bulk polymerization process, solves the problem of adding way of the catalyst, can prepare metallocene polypropylene with molecular weight distribution of 2-3 and isotacticity [ MMMM ] of more than 99 percent, and is particularly suitable for the application in the aspects of non-woven fabrics, spinning and the like.

Description

Preparation method and device of metallocene polypropylene

Technical Field

The invention relates to the field of metallocene polypropylene, and relates to a preparation method and a device of metallocene polypropylene.

Background

Polypropylene (PP) has become one of the most widely used plastics in the world and has the greatest yield due to its low density, good chemical stability, non-toxicity, easy processing, good mechanical properties, wide sources of raw materials, low price, etc. Traditional polypropylene is produced mainly by traditional Ziegler Natta catalysts, and emerging metallocene polypropylene (mPP) has the special properties of narrow molecular weight distribution, adjustable melt height and the like and is of great interest.

In the 90 s of the 20 th century, the industrial production of mPP began to develop vigorously, exxonMobil built a set of 100kt/a industrialization devices using EXXPOL single site catalyst, and the mass and slurry method was used to produce metallocene isotactic polypropylene under the trade name Achieve. At present, the commercially available metallocene polypropylene is developed by foreign companies, so that the development of high-performance polypropylene by using the existing propylene resources is significant.

Disclosure of Invention

The first aspect of the invention provides a preparation method of metallocene polypropylene, which comprises the step of carrying out bulk polymerization by taking propylene and optional hydrogen as raw materials in the presence of a catalyst, wherein the catalyst comprises a metallocene compound shown in a formula 1, a carrier and an optional cocatalyst,

according to some embodiments of the invention, the cocatalyst is selected from one or more of an alkyl aluminum, an alkyl aluminoxane, and an organoboride;

preferably, the alkyl aluminum is selected from one or more of trimethyl aluminum, triethyl aluminum and triisobutyl aluminum;

preferably, the alkylaluminoxane is selected from one or more of methylaluminoxane and ethylaluminoxane;

preferably, the organoboride is selected from one or more of trifluoroborane, triphenylborane, tris (4-fluorophenyl) borane, tris (pentafluorophenyl) borane, tris (3, 5-difluorophenyl) borane and tris (2, 4, 6-trifluorophenyl) borane;

preferably, the molar ratio of the metallocene compound to the cocatalyst, calculated as zirconium-aluminium ratio, is (200-3000): 1, further preferably (400-600): 1.

according to some embodiments of the invention, the reaction temperature of the reaction is-50 to 200 ℃, preferably 65 to 80 ℃.

According to some embodiments of the invention, the reaction time is 0.016 to 60 hours, preferably 3 to 7 hours.

According to some embodiments of the invention, the catalyst is used in an amount of 0.00001 to 100mg/g propylene, preferably 0.0001 to 10mg/g propylene.

According to some embodiments of the invention, the amount of the impurity breaker is 0 to 100mmol/g propylene, preferably 0.001 to 10mmol/g propylene.

According to some embodiments of the invention, the hydrogen is used in an amount of 0 to 0.10g/g propylene, preferably 0.0001 to 0.01g/100g propylene.

According to some embodiments of the invention, the feed lines for the catalyst and the breaking agent are shielded by an inert gas selected from one or more of nitrogen and argon.

According to some embodiments of the invention, the addition of the catalyst and the impurity breaker is achieved by means of a pressure difference of the gas.

According to some embodiments of the invention, the propylene has a purity of greater than 96%.

According to some embodiments of the invention, the hydrogen has a purity of greater than 98%.

The second aspect of the invention provides a preparation device of metallocene polypropylene, which comprises a reaction kettle, wherein a metering device for accurately calculating the mass of an added cocatalyst is arranged on the reaction kettle, and preferably, the metering device is a precision electronic scale.

According to some embodiments of the invention, the reaction kettle is provided with a catalyst sample inlet and a propylene gas sample inlet in sequence.

According to some embodiments of the invention, a discharge pipeline for materials is arranged at the bottom of the reaction kettle, and a discharge valve is arranged on the discharge pipeline.

The invention has the beneficial effects that:

(1) The metallocene compound of the invention prepares the supported metallocene catalyst, and the preparation of the metallocene polypropylene is realized by using a bulk polymerization method, and the obtained polypropylene has narrow molecular distribution (2-3), no peculiar smell and uniform particles. The preparation of polypropylene with different melt indexes can be realized by adjusting the addition amount of hydrogen.

(2) The autoclave was designed autonomously, the reactor obtained had the following advantages:

the catalyst charging port and the charging mode are designed and modified, so that the activity of the catalyst is well protected, and the catalyst is convenient to add; the auxiliary agent charging port and the charging mode are designed and modified, the usage amount of the auxiliary catalyst can be accurately measured by using the precise electronic scale, and the auxiliary catalyst is convenient to add; the polypropylene discharge port is more convenient.

Drawings

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate the invention and together with the embodiments of the invention, serve to explain the invention, without limitation to the invention. In the drawings:

FIG. 1 is a schematic structural view of an apparatus for preparing metallocene polypropylene according to an embodiment of the present invention.

Detailed Description

The present invention will be described in detail with reference to examples, but the present invention is not limited to the examples.

Wherein MAO is methylaluminoxane.

The testing method comprises the following steps:

polymerization activity= (mass of polyolefin produced)/(number of moles of zirconium in catalyst x reaction time), g/(mol·h) Mn, mw, PDI value: measured by high temperature GPC.

Percentage of isotactic sequence [ mmmm ] containing 5 consecutive isotactic units: 13C NMR spectroscopy.

1 into a preparation device of metallocene polypropylene:

on the basis of purchased polymerization reaction kettles, the automatic design of the autoclave is carried out again, wherein the automatic design comprises a main catalyst and cocatalyst charging opening and a charging mode. The upper part of the reaction kettle is provided with a catalyst feeding hole, inert gas is used for protecting, and the effective addition of the catalyst is realized by utilizing the pressure difference of the inert gas. The amount of cocatalyst was measured using a precision electronic scale. So that the addition and the metering of the catalyst are simpler, more convenient and more accurate. The autoclave is shown in figure 1, and the top is provided with a catalyst, a cocatalyst feeding port, a raw material gas injection port and a nitrogen injection port. The inert gas protects the catalyst and the impurity breaking agent, and the effective addition of the catalyst is realized by utilizing the pressure difference of the inert gas. The amount of cocatalyst was measured using a precision electronic scale. So that the addition and the metering of the catalyst are simpler, more convenient and more accurate. The bottom is provided with a discharge pipeline for materials, and a discharge valve is arranged on the pipeline.

2 preparation of metallocene Compounds

2g of silica gel which had been calcined at 600℃was weighed out, 10mL of MAO (methylaluminoxane) in toluene (10% by weight) was added and heated to 80 ℃. The toluene solution of the metallocene compound shown in the formula 1 is added under the condition of uniform stirring, the Al/Zr ratio is controlled to be 200:1, and the reaction is carried out overnight. The solid was collected by filtration and washed with toluene solvent until the washed solvent was colorless, and the solid was dried in vacuo for 24 hours to give a solid powder, which was stored in a glove box for use (this reaction procedure was used unless otherwise specified below). The catalyst with definite metal content can be obtained by measuring and calculating the feeding amount and the metal content of the washing liquid, wherein the zirconium content is 0.268% (29.4 mu mol/g).

Preparation of the catalyst: loading of metallocene Compounds

Under the anhydrous and anaerobic condition, 15g of MAO silica gel is weighed, 30mL of toluene is added until all the solution is dissolved, and a solution A is obtained;

and dissolving 6g of the prepared metallocene compound in 15mL of toluene, adding the solution A, reacting for more than 5 hours at room temperature, and carrying out suction filtration and drying to obtain the catalyst. And (5) standby application.

4 preparation of metallocene Polypropylene

Embodiment one:

2L high-pressure reaction kettle is selected and used, and the operation is carried out before polymerization: 1. pressure test is carried out to ensure good sealing performance of the whole device; 2. heating to 120 ℃ to ensure that water vapor impurities in the kettle are removed; 3. nitrogen was purged 3 times.

30mg of the prepared catalyst was weighed, 15mL of triisobutylaluminum solution (the concentration is 150. Mu. Mol/mL, the molar ratio of aluminum to zirconium is about 549:1) was added, 0.034g of hydrogen was added by a mass flow meter, the reaction time was 420 minutes, the reaction temperature was 75℃and the propylene amount was 680.2g by a mass flow meter.

540g of a polymer was obtained, and the polymerization activity was calculated to be 4.3X10 ⁸ g(PP)·mol ^-1 (Zr)·h ^-1 Mn 135427, mw 397892, PDI 2.938 by high temperature GPC; measurement of the isotactic sequence [ mmmm ] containing 5 continuous isotactic units by high-temperature 13C NMR spectrum]The percentage content of (2) was 98.4%. The melting point test value was 153.2 ℃.

Embodiment two:

105mg of the prepared catalyst, 8mL of triisobutylaluminum (the concentration is 150. Mu. Mol/mL, the molar ratio of aluminum to zirconium is about 549:1) was weighed, 0.034g of hydrogen was added by a mass flow meter, the reaction time was 180 minutes, the reaction temperature was 75 ℃, and 468g of propylene was added by a mass flow meter.

80g of a polymer having a calculated polymerization activity of 1.16X10 were obtained ⁷ g(PP)·mol ^-1 (Zr)·h ^-1 . Mn 133064, mw 313745 and PDI value 2.36 as measured by high temperature GPC; high temperature ¹³ C NMR spectrum shows an isotactic sequence [ mmmm ] containing 5 continuous isotactic units]The percentage content of (2) is 99.3%. The melting point test value was 149.4 ℃.

Embodiment III:

100mg of the prepared catalyst was weighed, 15mL of triisobutylaluminum (the concentration is 150. Mu. Mol/mL, the molar ratio of aluminum to zirconium is about 549:1), 0.034g of hydrogen was added by a mass flow meter, the reaction time was 240 minutes, the reaction temperature was 75 ℃, and 539g of propylene was added by a mass flow meter.

447g of a polymer having a calculated polymerization activity of 2.294X 10 were obtained ⁷ g(PP)·mol ^-1 (Zr)·h ^-1 . Mn of 198563, mw of 398423, PDI of 2.01, measured by high temperature GPC; high temperature ¹³ C NMR spectrum shows an isotactic sequence [ mmmm ] containing 5 continuous isotactic units]The percentage content of (2) is 99.2%. The melting point test value was 157.1 ℃.

Embodiment four:

60mg of the prepared catalyst was weighed, 20mL of triisobutylaluminum (the concentration is 150. Mu. Mol/mL, the molar ratio of aluminum to zirconium is about 1103:1), 0.026g of hydrogen was added by a mass flow meter, the reaction time was 240 minutes, the reaction temperature was 75 ℃, and 659g of propylene was added by a mass flow meter.

600g of a polymer having a calculated polymerization activity of 4.9X10 were obtained ⁷ g(PP)·mol ^-1 (Zr)·h ^-1 . Melt index mi=5.39 g/10min, mn of 178563 by high temperature GPC, mw 399423, pdi value of 2.24; high temperature ¹³ C NMR spectrum shows an isotactic sequence [ mmmm ] containing 5 continuous isotactic units]The percentage content of (2) is 99.2%. The melting point test value was 152.24 ℃.

Fifth embodiment:

30mg of the prepared catalyst was weighed, 20mL of triisobutylaluminum (concentration: 150. Mu. Mol/mL, molar ratio of aluminum to zirconium: about 2389:1), 0.026g of hydrogen was added by a mass flow meter, reaction time was 240 minutes, reaction temperature was 75 ℃, and propylene amount was 658.8g by a mass flow meter.

390g of a polymer having a calculated polymerization activity of 5.2X10 were obtained ⁷ g(PP)·mol ^-1 (Zr)·h ^-1 . Mn of 98318, mw of 285601, PDI value of 2.91 as measured by high temperature GPC; high temperature ¹³ C NMR spectrum shows an isotactic sequence [ mmmm ] containing 5 continuous isotactic units]The percentage content of (2) was 97.2%. The melting point test value was 147.9 ℃.

It should be noted that the above-described embodiments are only for explaining the present invention and do not constitute any limitation of the present invention. The invention has been described with reference to exemplary embodiments, but it is understood that the words which have been used are words of description and illustration, rather than words of limitation. Modifications may be made to the invention as defined in the appended claims, and the invention may be modified without departing from the scope and spirit of the invention. Although the invention is described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, as the invention extends to all other means and applications which perform the same function.

Claims

1. The preparation method of the metallocene polypropylene comprises the step of carrying out bulk polymerization reaction by taking propylene and optional hydrogen as raw materials in the presence of a catalyst, wherein the catalyst comprises a metallocene compound shown in a formula 1, a carrier and optional cocatalyst,

。

2. the method of claim 1, wherein the cocatalyst is selected from one or more of an alkyl aluminum, an alkyl aluminoxane, and an organoboride.

3. The method according to claim 2, wherein the alkyl aluminum is selected from one or more of trimethyl aluminum, triethyl aluminum, and triisobutyl aluminum.

4. The method according to claim 2, wherein the alkylaluminoxane is selected from one or more of methylaluminoxane and ethylaluminoxane.

5. The method of claim 2, wherein the organoboride is selected from one or more of trifluoroborane, triphenylborane, tris (4-fluorophenyl) borane, tris (pentafluorophenyl) borane, tris (3, 5-difluorophenyl) borane, and tris (2, 4, 6-trifluorophenyl) borane.

6. The process according to any one of claims 1 to 5, wherein the molar ratio of metallocene compound to cocatalyst, calculated as zirconium to aluminium ratio, is (200 to 3000): 1.

7. the process according to any one of claims 1 to 5, wherein the molar ratio of metallocene compound to cocatalyst, expressed as zirconium to aluminium ratio, is (400 to 600): 1.

8. the method according to any one of claims 1 to 5, wherein the carrier is selected from the group consisting of SiO ₂ 、MgCl ₂ And Al ₂ O ₃ One or more of the following.

9. The method according to any one of claims 1 to 5, wherein the reaction temperature of the reaction is-50 to 200 ℃;

and/or the reaction time is 0.016 to 60 hours.

10. The method according to claim 9, wherein the reaction temperature of the reaction is 65-80 ℃;

and/or the reaction time is 3-7h.

11. The process according to any one of claims 1 to 5, wherein the catalyst is used in an amount of 0.00001 to 100mg/g propylene;

and/or the dosage of the impurity breaking agent is 0-100 mmol/g propylene;

and/or the hydrogen is used in an amount of 0 to 0.10g/g propylene.

12. The process according to claim 11, wherein the catalyst is used in an amount of 0.0001-10mg/g propylene;

and/or the dosage of the impurity breaking agent is 0.001-10 mmol/g propylene;

and/or the hydrogen is used in an amount of 0.0001 to 0.01g/100g propylene.

13. The process of any one of claims 1-5, wherein the feed lines for the catalyst and the breaker are shielded by an inert gas selected from one or more of nitrogen and argon;

and/or the addition of the catalyst and the impurity breaker is achieved by means of a pressure difference of the gases.

14. The process of any one of claims 1-5, wherein the propylene has a purity greater than 96%;

and/or the purity of the hydrogen is greater than 98%.