A catalyst for ultrahigh to ultra-high molecular weight polyethylene and a preparation method and application thereof

Abstract

The application provides a catalyst for ultrahigh to superhigh molecular weight polyethylene and a preparation method and application thereof. The catalyst for ultrahigh to superhigh molecular weight polyethylene comprises anhydrous active magnesium chloride as a carrier and a half-molybdenum binuclear titanium compound as an active component. The magnesium content in the catalyst for ultrahigh to superhigh molecular weight polyethylene is 10-30 wt%, the aluminum content is 2-4 wt%, the titanium content is 2-10 wt%, and the chlorine content is 30-70 wt%. The catalyst for ultrahigh to superhigh molecular weight polyethylene can be used to prepare ultrahigh to superhigh molecular weight polyethylene microparticles with high bulk density, fine particle size and narrow particle size distribution.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of polyethylene preparation, and particularly relates to a catalyst for preparing ultrahigh molecular weight polyethylene and a preparation method and application thereof. BACKGROUND

[0002] Ultrahigh molecular weight polyethylene is a kind of thermoplastic engineering plastic with high impact resistance, very high wear resistance, high corrosion resistance, self-lubricating property, environmental stress cracking resistance, safety and health, and is widely used in many fields such as textiles, papermaking, transportation, packaging, machinery, chemical industry, mining, petroleum, agriculture, medical treatment, fine filtration, battery separator and the like.

[0003] At present, the catalysts for producing ultrahigh molecular weight polyethylene mainly include Ziegler-Natta type, chromium type, metallocene type, non-metallocene type and the like, but the most widely used and the most mature technology is still Z-N catalyst. In the existing technology, the particle size of the active magnesium chloride carrier is generally controlled by chemical method, and the particle size of the catalyst is controlled in this way, so as to obtain a controllable polymer particle size. There are many reports on ultrahigh molecular weight polyethylene catalysts, and the existing technology mainly focuses on improving the activity of the catalyst, the molecular weight of the polymer and the bulk density of the polymer, the use of additives and the control of operation steps in the preparation process of the catalyst, and most of the catalysts prepared by the above-mentioned methods have a particle size of more than 5 microns (D50), and the particle size (D50) of the produced ultrahigh molecular weight polymer mainly ranges from 150 microns to 250 microns, or the coarse particles with a particle size of more than 600 microns. The above-mentioned methods cannot obtain a polymer with a finer particle size.

[0004] CN101061144A discloses ethylene-based polymer microparticles and a catalyst for producing the same, the polymer microparticles have a weight ratio of at least 95% or more passing through a mesh screen of 37 microns, and a median diameter (d 50 ) of 3 microns ≤ d 50 ≤ 25 microns measured by a laser diffraction scattering method. The polymer needs a complicated step of removing inorganic impurities, and the preparation process of the catalyst reported in the method must use the regulated solvent toluene as a solvent.

[0005] CN113912759A reports that an O, N, S / P tridentate complex is used to prepare ultrahigh molecular weight polyethylene, the polyethylene microparticles have a viscosity average molecular weight of 500,000-1,500,000 g / mol, ≥95 wt% can pass through a mesh screen of 100 microns, and d 50 is 40 microns ≤ d 50 ≤ 80 microns. The ultrahigh molecular weight polyethylene powder is prepared into a lithium battery separator, and the prepared separator has good tensile strength and puncture strength. However, the powder bulk density is <0.4 g / cm 3, and cannot meet the industrial production requirements of lithium battery separators. The tap density of the ultra-high molecular weight polyethylene powder prepared by other schemes disclosed in the prior art is low, which does not meet the requirements of ultra-high molecular weight polyethylene fiber manufacturers. Ultra-high molecular weight polyethylene fiber manufacturers require that the tap density of ultra-high molecular weight polyethylene powder be at least 0.45 g / cm 3 , and the production requirements can be met.

[0006] In summary, the types of catalysts for fine particle size ultrahigh to ultra-high molecular weight polyethylene are few, but most of them are not practical. Therefore, it is of great significance to develop new types of catalyst systems with practicality. SUMMARY

[0007] In order to solve the problem of low tap density of the ultra-high molecular weight polyethylene powder prepared in the prior art, the purpose of the present application is to provide a catalyst for ultrahigh to ultra-high molecular weight polyethylene and a preparation method and application thereof. The catalyst for ultrahigh to ultra-high molecular weight polyethylene can be used to prepare ultrahigh to ultra-high molecular weight polyethylene microparticles with high tap density, fine particle size and narrow particle size distribution.

[0008] In order to achieve the above purpose, the present application provides a catalyst for ultrahigh to ultra-high molecular weight polyethylene, wherein anhydrous active magnesium chloride is used as a carrier, and a half-metallocene binuclear titanium compound is used as an active component; the magnesium content in the catalyst for ultrahigh to ultra-high molecular weight polyethylene is 10-30 wt%, the aluminum content is 2-4 wt%, the titanium content is 2-10 wt%, and the chlorine content is 30-70 wt%, based on 100% of the mass of the catalyst for ultrahigh to ultra-high molecular weight polyethylene;

[0009] The anhydrous active magnesium chloride is in-situ active magnesium chloride, and the molecular formula of the in-situ active magnesium chloride is (MgCl2)(R 1 MgCl) a Mg b [Ti(OR 2 )4)] c [Si(OR 3 )4] d , R 1 , R 2 and R 3 are the same or different, and each is independently selected from C 1-12 alkyl, a=0.02-1, b=0-0.5, c=0-0.8, and d=0-0.8;

[0010] The half-metallocene binuclear titanium compound has a structure represented by Formula I, Formula II or Formula III:

[0011]

[0012]

[0013] in formula I to formula III:

[0014] m, n are each independently selected from 0, 1, 2, 3, 4; z, y are each independently selected from 0, 1, 2, 3, 4, 5;

[0015] a plurality of R1, R2, R3, R4 are the same or different, each independently selected from H, C 1-20 alkyl, C 6-20 aryl, 5-20 membered heteroaryl, R a monosubstituted or polysubstituted C 1-20 alkyl, R a monosubstituted or polysubstituted C 6-20 aryl, R a monosubstituted or polysubstituted 5-20 membered heteroaryl;

[0016] a plurality of R a are the same or different, each independently selected from halogen, C 1-20 alkyl, C 6-20 aryl, 5-20 membered heteroaryl;

[0017] and / or, two adjacent R1 are connected as end groups to form a 5-20 membered heteroaryl and a fused ring structure of the benzene ring;

[0018] and / or, two adjacent R2 are connected as end groups to form a 5-20 membered heteroaryl and a fused ring structure of the benzene ring;

[0019] and / or, two adjacent R3 are connected as end groups to form a 5-20 membered heteroaryl and a fused ring structure of the cyclopentadiene;

[0020] and / or, two adjacent R4 are connected as end groups to form a 5-20 membered heteroaryl and a fused ring structure of the cyclopentadiene.

[0021] According to a specific embodiment of the present application, preferably, the in-situ active magnesium chloride includes (MgCl2)(BuMgCl) 0.59 and / or (MgCl2)(BuMgCl) 0.58 Mg 0.08 [Ti(OC4H9)4)] 0.07 [Si(OC2H5)4] 0.23 .

[0022] According to a specific embodiment of the present application, preferably, the preparation method of the in-situ active magnesium chloride refers to CN113943384A, not limited to the preparation method of the in-situ active magnesium chloride in Example 1 of CN113943384A.

[0023] According to a specific embodiment of the present application, preferably, the plurality of R1, R2, R3, R4, are the same or different, each independently selected from the group consisting of H, C 1-6 alkyl, C 6-8 aryl, 5-8 membered heteroaryl, R a mono- or poly-substituted C 1-6 alkyl, R a mono- or poly-substituted C 6-8 aryl, R a mono- or poly-substituted 5-8 membered heteroaryl; more preferably selected from the group consisting of H, C 1-6 alkyl, C 6-8 aryl, 5-8 membered heteroaryl; further preferably selected from the group consisting of H, methyl, isopropyl, tert-butyl.

[0024] According to a specific embodiment of the present application, preferably, m, n are each independently selected from 0, 1, 2, 3; z, y are each independently selected from 0, 1, 2, 3.

[0025] According to a specific embodiment of the present application, preferably, the plurality of R a are the same or different, each independently selected from the group consisting of halogen, C 1-6 alkyl, C 6-8 aryl, 5-8 membered heteroaryl; more preferably selected from the group consisting of halogen, C 1-6 alkyl.

[0026] According to a specific embodiment of the present application, preferably, two adjacent R1 are connected as end groups to form a 5-14 membered heteroaryle and benzene fused ring structure, more preferably a 5-10 membered heteroaryle and benzene fused ring structure.

[0027] According to a specific embodiment of the present application, preferably, two adjacent R2 are connected as end groups to form a 5-14 membered heteroaryle and benzene fused ring structure, more preferably a 5-10 membered heteroaryle and benzene fused ring structure.

[0028] According to a specific embodiment of the present application, preferably, two adjacent R3 are connected as end groups to form a 5-14 membered heteroaryle and cyclopentadiene fused ring structure, more preferably a 5-10 membered heteroaryle and cyclopentadiene fused ring structure.

[0029] According to a specific embodiment of the present application, preferably, two adjacent R4 are connected as end groups to form a 5-14 membered heteroaryle and cyclopentadiene fused ring structure, more preferably a 5-10 membered heteroaryle and cyclopentadiene fused ring structure.

[0030] According to a specific embodiment of the present application, preferably, two adjacent R1 or R2 are connected as end groups to form an anthracene together with the benzene ring.

[0031] According to a specific embodiment of the present application, preferably, two adjacent R3or R4are connected as end groups together with the cyclopentadiene to form an indene.

[0032] According to a specific embodiment of the present application, preferably, the half-metallocene dinuclear titanium compound is selected from one or a combination of two or more of the following compounds:

[0033]

[0034] According to a specific embodiment of the present application, preferably, in the ultrahigh to ultra-high molecular weight polyethylene catalyst, the magnesium content is 10-20wt%, the aluminum content is 2.5-3.5wt%, and the titanium content is 2-7wt%.

[0035] According to a specific embodiment of the present application, preferably, the particle size of the ultrahigh to ultra-high molecular weight polyethylene catalyst is 0.5μm≤D50≤3μm, more preferably 1.5μm≤D50≤2μm.

[0036] The present application also provides a preparation method of the above-mentioned ultrahigh to ultra-high molecular weight polyethylene catalyst, which comprises the following steps:

[0037] (1) Under a protective gas atmosphere, the anhydrous active magnesium chloride is mixed with an alkane solvent, an alcohol reagent is added, and the reaction is carried out at 40-80℃ for 1-4h to obtain a modified active alcoholized magnesium chloride carrier;

[0038] (2) Under a protective gas atmosphere, the modified active alcoholized magnesium chloride carrier obtained in step (1) is mixed with an alkane solvent, cooled to -30-10℃, an aluminum reagent is added, and the temperature is raised to 20-60℃, and the reaction is carried out for 1-3h to obtain an activated carrier containing an aluminum reagent;

[0039] (3) The activated carrier containing an aluminum reagent obtained in step (2) is mixed with an alkane solvent, the half-metallocene dinuclear titanium compound is added at -30-10℃, the temperature is raised to 20-50℃, and the reaction is carried out for 4-8h to obtain the ultrahigh to ultra-high molecular weight polyethylene catalyst.

[0040] According to a specific embodiment of the present application, preferably, in step (1), the molar ratio of the alcohol reagent to the anhydrous active magnesium chloride is 0.3-6, more preferably 0.5-2.

[0041] According to a specific embodiment of the present application, preferably, the reaction temperature in step (1) is 50-70℃, more preferably 60℃.

[0042] According to a specific embodiment of the present application, preferably, the alkane solvent comprises C5-C30 paraffin and / or C5-C30 cycloparaffin; more preferably comprises C5-C10 paraffin and / or C5-C10 cycloparaffin; further preferably comprises one or more than one combination of hexane, heptane, octane, nonane, decane, such as hexane and / or decane.

[0043] According to a specific embodiment of the present application, preferably, in step (1), the alcohol reagent comprises one or more than one combination of C1-C10 alcohol, more preferably comprises one or more than one combination of methanol, ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, 2-ethylhexanol, n-octanol.

[0044] According to a specific embodiment of the present application, preferably, in step (2), the aluminum reagent comprises one or more than one combination of dichloroethylaluminum, diethylaluminum chloride, triethylaluminum, triisobutylaluminum, ethylaluminum sesquichloride, butylaluminum sesquichloride, methylaluminoxane (MAO), modified methylaluminoxane (MMAO), more preferably methylaluminoxane (MAO) and / or modified methylaluminoxane (MMAO).

[0045] According to a specific embodiment of the present application, preferably, in step (2), the temperature is lowered to -20℃ to 0℃ before adding the aluminum reagent, more preferably -10℃.

[0046] According to a specific embodiment of the present application, preferably, in step (2), the temperature is raised to 20℃ to 50℃ for reaction, more preferably 25℃.

[0047] According to a specific embodiment of the present application, preferably, in step (3), the semi-metallocene binuclear titanium compound is added at -20℃ to 0℃, more preferably -10℃.

[0048] According to a specific embodiment of the present application, preferably, in step (3), the temperature is raised to 20℃ to 40℃ for reaction, more preferably 25℃.

[0049] According to a specific embodiment of the present application, preferably, in step (3), the reaction time is 5-7h, more preferably 6h.

[0050] According to a specific embodiment of the present application, the preparation method of the above-mentioned very high to ultra-high molecular weight polyethylene catalyst comprises the following specific steps:

[0051] (1) Put magnesium powder into a three-necked flask under nitrogen protection, add decane, a small amount of iodine, and n-chlorobutane; heat to 70-80℃ and stir, drop n-chlorobutane, continue to react for 1-4 hours, filter, wash with hexane and dry to obtain an in-situ active magnesium chloride carrier;

[0052] (2) under nitrogen protection, the in-situ active magnesium chloride is added into an inert alkane solvent, an alcohol is added under stirring to contact the magnesium chloride (the molar ratio of the alcohol to the anhydrous active magnesium chloride is 0.3-1), and the reaction is carried out at 60-110℃ for 1-4h, then filtration, drying, to obtain a modified active alcoholated magnesium chloride carrier;

[0053] (3) an alkane solvent and the modified active alcoholated magnesium chloride carrier are added into a reaction kettle under nitrogen protection, the temperature is lowered to -30℃ to 10℃ under stirring, an aluminum reagent is slowly added dropwise, after the dropwise addition is completed, the temperature is raised to 20℃ to 50℃, and after stirring for a period of time, filtration is carried out, and washing is carried out, to obtain an activated carrier containing the aluminum reagent;

[0054] (4) an inert alkane and the activated carrier containing the aluminum reagent are added into a reaction kettle, the temperature is set to -30℃ to 10℃, a half-metallocene binuclear titanium compound solution is slowly added dropwise under stirring, the temperature is raised to 20℃ to 50℃, and stirring is carried out for 4-8h, then filtration, n-hexane washing, and drying, to obtain a very high to ultrahigh molecular weight polyethylene catalyst.

[0055] The application further provides a very high to ultrahigh molecular weight polyethylene catalyst system, which comprises the very high to ultrahigh molecular weight polyethylene catalyst and a cocatalyst.

[0056] According to a specific embodiment of the application, preferably, the cocatalyst comprises an organic aluminum compound R 3-b A1X b , wherein X is halogen, R is C 1-12 alkyl, and b is an integer of 0-2.

[0057] According to a specific embodiment of the application, preferably, the molar ratio of aluminum in the cocatalyst to titanium in the very high to ultrahigh molecular weight polyethylene catalyst is 10-300, more preferably 20-200, and further preferably 30-100.

[0058] The application further provides a preparation method of very high to ultrahigh molecular weight polyethylene, which adopts the very high to ultrahigh molecular weight polyethylene catalyst system to carry out a polymerization reaction, the reaction temperature is 30-90℃, and the reaction pressure is 0.1-1.0MPa; more preferably, the reaction temperature is 40-87℃, and the reaction pressure is 0.2-0.8MPa.

[0059] The application further provides very high to ultrahigh molecular weight polyethylene, which is prepared by the preparation method of very high to ultrahigh molecular weight polyethylene; the intrinsic viscosity of the very high to ultrahigh molecular weight polyethylene is 4-40dl / g, the median particle size D 50 is 50μm to 100μm, the particle size distribution is 0.5-0.7, the bulk density is ≥0.450g / cm 3 , the ash content is <200ppm, and the viscosity average molecular weight is 4-10 million.

[0060] The catalyst system of the present application can be used to prepare ultra-high molecular weight polyethylene microparticles with high bulk density, fine particle size and narrow particle size distribution (50 μm≤D 50 ≤100 μm) and ultra-high molecular weight (viscosity average molecular weight of 4-10 million). BRIEF DESCRIPTION OF DRAWINGS

[0061] Figure 1 is a schematic diagram of the single crystal structure of the half-metallocene binuclear titanium compound 8;

[0062] Figure 2 is a SEM electron microscope photo of the polymer obtained in Example 8;

[0063] Figure 3 is a SEM electron microscope photo of the polymer obtained in Example 8. DETAILED DESCRIPTION

[0064] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solutions of the present application are described in detail below, but it should not be understood as limiting the scope of the present application.

[0065] The intrinsic viscosity is determined according to the standard of ASTM D4020-05 by using a high-temperature Ubbelohde viscometer, and the viscosity average molecular weight is calculated: M = 5.37 x 10 4 × [η] 1.49 .

[0066] The particle size of the polyethylene is determined by a laser particle analyzer (Mastersizer X, Malvern), wherein D 10 , D 50 and D 90 distribution refers to the size of the particles at each percentage of 10, 50 and 90. D 50 is defined as the median particle size, which is used to represent the average particle size of the powder. The particle size distribution is defined as (D 90 -D 10 ) / D 50 ;

[0067] The single crystal structure is tested by a double microfocus spot single crystal diffractometer, manufacturer: Rigaku Oxford Diffract;

[0068] The bulk density is tested according to GB / T1636-2008;

[0069] The ash content is tested according to GB / T9345.5-2010;

[0070] Preparation Example 1

[0071] The present embodiment provides an ultrahigh to ultrahigh molecular weight polyethylene catalyst, which comprises a half-metallocene binuclear titanium compound 1 prepared by the following steps:

[0072]

[0073] (1) Preparation of half-metallocene binuclear titanium compound 1: 250 ml of three-necked flask, nitrogen replacement three times, 5 mmol of 2,2'-dihydroxydiphenyl, 50 mL of dry toluene were added in turn, stirred and dissolved, n-butyllithium (4.2 mL, 2.4 mol / L) was slowly dropped at 0 ℃, white precipitate was immediately generated, then naturally warmed to room temperature (25 ℃) for 2 h, white emulsion was obtained, which was lithium salt solution; 2.5 mmol of cyclopentadienyl titanium trichloride toluene solution was warmed to 105 ℃, the lithium salt solution was dropped into the cyclopentadienyl titanium trichloride toluene solution under nitrogen protection, heated and refluxed for 36 h; then cooled to room temperature, filtered, the filtrate was concentrated under vacuum to about 5 mL, 15 mL of freshly distilled n-hexane was added, filtered, the solid was washed twice with 10 mL of n-hexane, and the orange-red half-metallocene binuclear titanium compound 1 was obtained. Yield: 64%. The elemental analysis results are as follows: C%: measured value 47.75 (theoretical value 47.88); H%: 3.19 (theoretical value 3.29); Ti%: 17.21 (theoretical value 17.35);

[0074] (2) Under nitrogen protection, 0.1 mol of in-situ active magnesium chloride (MgCl2) (BuMgCl) 0.59 (Prepared according to CN113943384A embodiment 1) was added into 100 mL of hexane, 0.06 mol of isooctanol was added under stirring, and the reaction was carried out at 60 ℃ for 2 hours. After filtration and drying, the modified active alcoholized magnesium chloride carrier was obtained;

[0075] (3) The modified active alcoholized magnesium chloride carrier 5 g was added into 100 mL of hexane under nitrogen protection, cooled to -10 ℃, and 10 mL of MMAO solution (solvent: toluene; 10 wt%) was slowly added. After the dropping was completed, the temperature was raised to room temperature, and the stirring was carried out for 1 hour. After filtration and solvent extraction, the active carrier containing aluminum reagent 4.1 g was obtained;

[0076] (4) Under stirring, the active carrier containing aluminum reagent 4 g was added into 100 mL of hexane, and 0.05 mol of half-metallocene binuclear titanium compound 1 (dissolved in 10 mL of toluene) was slowly dropped at -10 ℃. The temperature was raised to room temperature, and the stirring was carried out for 6 hours. After filtration and n-hexane washing and drying, the ultrahigh to ultrahigh molecular weight polyethylene catalyst a was obtained, with a total weight of 3.7 g and a particle size of 1.8 μm. The titanium content was 3.1 wt%, the magnesium content was 17.0 wt%, the aluminum content was 3.1 wt%, and the chlorine content was 51.2 wt%.

[0077] Preparation Example 2

[0078] This embodiment provides a high to ultra-high molecular weight polyethylene catalyst, which comprises a semi-cenete binuclear titanium compound 2, and is prepared by the following steps:

[0079]

[0080] The preparation method was the same as in Preparation Example 1, except that in step (1), cyclopentadienyl titanium trichloride was replaced with pentamethylcyclopentadienyl titanium trichloride. The elemental analysis results of the semi-cerotropylated dinuclear titanium compound 2 were: C%: measured value 55.61 (theoretical value 55.53); H%: 5.49 (theoretical value 5.53); Ti%: 13.79 (theoretical value 13.83). The obtained ultra-high to ultra-high molecular weight polyethylene catalyst b had a particle size of 1.8 μm; the determined titanium content was 3.4 wt%, magnesium content was 16.8 wt%, aluminum content was 2.9 wt%, and chlorine content was 49.7 wt%.

[0081] Preparation Example 3

[0082] This embodiment provides a high to ultra-high molecular weight polyethylene catalyst, which comprises a semi-cenete binuclear titanium compound 3, and is prepared by the following steps:

[0083]

[0084] The preparation method was the same as in Preparation Example 1, except that in step (1), cyclopentadienyl titanium trichloride was replaced with indene titanium trichloride. The elemental analysis results of the semi-ceramic dinuclear titanium compound 3 were: C%: measured value 55.30 (theoretical value 55.26); H%: 3.35 (theoretical value 3.40); Ti%: 14.71 (theoretical value 14.68). The obtained ultra-high to ultra-high molecular weight polyethylene catalyst c had a particle size of 1.7 μm; the determined titanium content was 3.5 wt%, magnesium content was 17.5 wt%, aluminum content was 3.0 wt%, and chlorine content was 50.5%.

[0085] Preparation Example 4

[0086] This embodiment provides a catalyst for ultra-high to extra-high molecular weight polyethylene, which comprises a semi-cenete binuclear titanium compound 4, and is prepared by the following steps:

[0087]

[0088] The preparation method is the same as that of Preparation Example 1, except that in step (1), the 2,2'-biphenol is replaced by 4,4'-dimethyl-2,2'-biphenol (CAS: 52751-74-3). The elemental analysis results of the half-metallocene dinuclear titanium compound 4 are: C%: found 49.55 (theoretical value 49.70); H%: 3.90 (theoretical value 3.82); Ti%: 16.42 (theoretical value 16.51). The obtained ultra-high to ultra-high molecular weight polyethylene catalyst d has a catalyst particle size of 1.7 μm; the titanium content is 3.4 wt%, the magnesium content is 18.1 wt%, the aluminum content is 3.3 wt%, and the chlorine content is 52.4 wt%.

[0089] Preparation Example 5

[0090] This example provides an ultra-high to ultra-high molecular weight polyethylene catalyst, which comprises a half-metallocene dinuclear titanium compound 5, which is prepared by the following steps:

[0091]

[0092] The preparation method is the same as that of Preparation Example 1, except that in step (1), the 2,2'-biphenol is replaced by 4,4'-dimethyl-2,2'-biphenol (CAS: 52751-74-3). The elemental analysis results of the half-metallocene dinuclear titanium compound 4 are: C%: found 49.55 (theoretical value 49.70); H%: 3.90 (theoretical value 3.82); Ti%: 16.42 (theoretical value 16.51). The obtained ultra-high to ultra-high molecular weight polyethylene catalyst d has a catalyst particle size of 1.7 μm; the titanium content is 3.4 wt%, the magnesium content is 18.1 wt%, the aluminum content is 3.3 wt%, and the chlorine content is 52.4 wt%.

[0093] Preparation Example 6

[0094] This example provides an ultra-high to ultra-high molecular weight polyethylene catalyst, which comprises a half-metallocene dinuclear titanium compound 6, which is prepared by the following steps:

[0095]

[0096] The preparation method is the same as that of Preparation Example 1, except that in step (1), the cyclopentadienyl titanium trichloride is replaced with indenyl titanium trichloride, and the 2,2'-biphenol is replaced with 4,4'-dimethyl-2,2'-dihydroxybiphenyl. The elemental analysis results of the half-metallocene dinuclear titanium compound 6 are: C%: found 56.55 (theoretical value 56.51); H%: 3.85 (theoretical value 3.85); Ti%: 14.21 (theoretical value 14.08). The obtained ultra-high to ultra-high molecular weight polyethylene catalyst f has a catalyst particle size of 1.7 μm; the titanium content is 3.2 wt%, the magnesium content is 18.0 wt%, the aluminum content is 3.4 wt%, and the chlorine content is 52.1 wt%.

[0097] Preparation Example 7

[0098] This example provides an ultra-high to ultra-high molecular weight polyethylene catalyst, which comprises a half-metallocene dinuclear titanium compound 7, which is prepared by the following steps:

[0099]

[0100] The preparation method is the same as that of Preparation Example 1, except that in step (1), the 2,2'-biphenol is replaced with 1,1'-binaphthol (CAS: 602-09-5). The elemental analysis results of the half-metallocene dinuclear titanium compound 7 are: C%: found 55.24 (theoretical value 55.26); H%: 3.58 (theoretical value 3.40); Ti%: 14.71 (theoretical value 14.68). The obtained ultra-high to ultra-high molecular weight polyethylene catalyst g has a catalyst particle size of 1.6 μm; the titanium content is 3.1 wt%, the magnesium content is 17.5 wt%, the aluminum content is 2.9 wt%, and the chlorine content is 50.1 wt%.

[0101] Preparation Example 8

[0102] This example provides an ultra-high to ultra-high molecular weight polyethylene catalyst, which comprises a half-metallocene dinuclear titanium compound 8, which is prepared by the following steps:

[0103]

[0104] The preparation method is the same as that of Preparation Example 1, except that in step (1), the cyclopentadienyl titanium trichloride is replaced with indenyl titanium trichloride, and the 2,2'-biphenol is replaced with 2,2'-binaphthol. The elemental analysis results of the half-metallocene dinuclear titanium compound 9 are: C%: measured value 60.59 (theoretical value 60.68); H%: 3.44 (theoretical value 3.48); Ti%: 12.81 (theoretical value 12.73). The catalyst particle size is 1.8 μm; the obtained ultrahigh to ultra-high molecular weight polyethylene catalyst i is measured to have a titanium content of 3.2 wt%, a magnesium content of 18.4 wt%, an aluminum content of 3.4 wt%, and a chlorine content of 53.1 wt%.

[0105] In order to further determine the structure of the complex, red block single crystals are grown in a toluene / n-hexane mixed solution. Crystallographic data: monoclinic system, space group P21 / c, β(°)=94.4580(10), unit cell volume Z=4. The crystal structure is shown in Figure 1 Preparation Example 9

[0106] This example provides an ultrahigh to ultra-high molecular weight polyethylene catalyst, which comprises a half-metallocene dinuclear titanium compound 9, and is prepared by the following steps:

[0107]

[0108] The preparation method is the same as that of Preparation Example 1, except that in step (1), the cyclopentadienyl titanium trichloride is replaced with indenyl titanium trichloride, and the 2,2'-biphenol is replaced with 2,2'-binaphthol. The elemental analysis results of the half-metallocene dinuclear titanium compound 9 are: C%: measured value 60.59 (theoretical value 60.68); H%: 3.44 (theoretical value 3.48); Ti%: 12.81 (theoretical value 12.73). The catalyst particle size is 1.8 μm; the obtained ultrahigh to ultra-high molecular weight polyethylene catalyst i is measured to have a titanium content of 3.2 wt%, a magnesium content of 18.4 wt%, an aluminum content of 3.4 wt%, and a chlorine content of 53.1 wt%.

[0109] Preparation Example 10

[0110] This example provides an ultrahigh to ultra-high molecular weight polyethylene catalyst, which is prepared by the same method as that of Preparation Example 8, except that in step (4), the amount of the half-metallocene dinuclear titanium compound is reduced to 0.02 mol. The obtained ultrahigh to ultra-high molecular weight polyethylene catalyst j has a catalyst particle size of 1.7 μm; and is measured to have a titanium content of 2.1 wt%, a magnesium content of 18.7 wt%, an aluminum content of 3.1 wt%, and a chlorine content of 52.8 wt%.

[0111] Preparation Example 11

[0112] This example provides a very high to ultra high molecular weight polyethylene catalyst, the catalyst preparation method is the same as that of Preparation Example 8, the difference is that the amount of half-molybdenum double-core titanium compound in step (4) is increased to 0.1 mol. The obtained very high to ultra high molecular weight polyethylene catalyst k, the catalyst particle size is 1.7 μm; the titanium content is 3.9 wt%, the magnesium content is 17.9 wt%, the aluminum content is 2.9 wt%, and the chlorine content is 51.8 wt%.

[0113] Preparation Example 12

[0114] This example provides a very high to ultra high molecular weight polyethylene catalyst, the catalyst preparation method is the same as that of Preparation Example 8, the difference is that the amount of half-molybdenum double-core titanium compound in step (4) is increased to 0.1 mol. The obtained very high to ultra high molecular weight polyethylene catalyst k, the catalyst particle size is 1.7 μm; the titanium content is 3.9 wt%, the magnesium content is 17.9 wt%, the aluminum content is 2.9 wt%, and the chlorine content is 51.8 wt%.

[0115] Preparation Example 13

[0116] This example provides a very high to ultra high molecular weight polyethylene catalyst, the catalyst preparation method is the same as that of Preparation Example 8, the difference is that the amount of half-molybdenum double-core titanium compound in step (4) is increased to 0.1 mol. The obtained very high to ultra high molecular weight polyethylene catalyst k, the catalyst particle size is 1.7 μm; the titanium content is 3.9 wt%, the magnesium content is 17.9 wt%, the aluminum content is 2.9 wt%, and the chlorine content is 51.8 wt%.

[0117] Examples 1-13

[0118] The catalysts obtained in Preparation Examples 1-13 above were respectively polymerized by the following method, and the polymerization results are shown in Table 1:

[0119] In a 4.0 cubic meter stainless steel autoclave, after nitrogen replacement, dehydrated hexane (water content <10 ppm) 2.8 cubic meters, triethyl aluminum hexane solution (according to the Al / Ti molar ratio of 30), and very high to ultra high molecular weight polyethylene catalyst 20 g were sequentially added, the stirring speed was 500 rpm, the temperature was raised to 50°C, then ethylene was introduced until the autoclave pressure was 0.5 MPa (gauge pressure), at 70°C, the autoclave pressure was maintained at 0.5 MPa, after 2 h of polymerization reaction, the ethylene was stopped, the pressure was absorbed, and the temperature was lowered to room temperature, after drying, the ultra high molecular weight polyethylene product was obtained, and the catalyst activity was determined, the bulk density was measured, the intrinsic viscosity was measured, the average particle size and particle size distribution were measured, and the results are shown in Table 1.

[0120] Table 1

[0121]

[0122] Examples 14-26

[0123] The catalysts obtained in Preparation Examples 1-13 above were polymerized respectively in the following manner, and the polymerization results are shown in Table 2.

[0124] In a 4.0 cubic meter stainless steel autoclave, after replacement by nitrogen, dehydrated hexane (water content <10 ppm) 2.8 cubic meters, triethylaluminum hexane solution (feeding according to Al / Ti molar ratio of 30), and extra-high to ultra-high molecular weight polyethylene catalyst 20 g were added successively, stirring speed 500 rpm, temperature was raised to 50°C, then ethylene was introduced until the autoclave pressure reached 0.5 MPa (gauge pressure), at 85°C, the autoclave pressure was kept at 0.5 MPa, continuous introduction of hydrogen was controlled, the ethylene / hydrogen mass ratio was 3000:1. After 2 h of polymerization reaction, the introduction of ethylene was stopped, the pressure was absorbed, and the temperature was lowered to room temperature, after drying the product was obtained. The catalyst activity was measured, the bulk density was measured, the intrinsic viscosity was measured, the average particle size and particle size distribution were measured, and the results are shown in Table 2.

[0125] Table 2

[0126]

[0127] Example 27

[0128] The catalyst prepared in Preparation Example 8 was polymerized in the following manner, and the polymerization results are shown in Table 3.

[0129] In a 4.0 cubic meter stainless steel autoclave, after replacement by nitrogen, dehydrated hexane (water content <10 ppm) 2.8 cubic meters, triethylaluminum hexane solution (feeding according to Al / Ti molar ratio of 30), and extra-high to ultra-high molecular weight polyethylene catalyst 20 g were added successively, stirring speed 500 rpm, temperature was raised to 50°C, then ethylene was introduced until the autoclave pressure reached 0.5 MPa (gauge pressure), at 85°C, the autoclave pressure was kept at 0.5 MPa, continuous introduction of hydrogen was controlled, the ethylene / hydrogen mass ratio was 3000:1. After 2 h of polymerization reaction, the introduction of ethylene was stopped, the pressure was absorbed, and the temperature was lowered to room temperature, after drying the product was obtained. The catalyst activity was measured, the bulk density was measured, the intrinsic viscosity was measured, the average particle size and particle size distribution were measured, and the results are shown in Table 2.

[0130] Table 3

[0131]

[0132] Example 28

[0133] The catalyst prepared in Preparation Example 8 was polymerized in the following manner, and the polymerization results are shown in Table 4.

[0134] In a 4.0 cubic meter stainless steel autoclave, after nitrogen replacement, 2.8 cubic meters of dehydrated hexane (water content <10 ppm), 30 moles of triethylaluminum hexane solution (according to the AI / Ti molar ratio of 30), and 20 grams of ultra-high molecular weight polyethylene catalyst were sequentially added, the stirring speed was 500 rpm, the temperature was raised to the set temperature, then ethylene was introduced until the autoclave pressure reached the set pressure, at the set temperature, the autoclave pressure was maintained at the set pressure, and a certain proportion of ethylene / hydrogen was continuously introduced. After 2 hours of polymerization reaction, the ethylene was stopped, the pressure was absorbed, the temperature was lowered to room temperature, and the product was obtained after drying. The catalyst activity was determined, the bulk density was measured, the intrinsic viscosity was measured, the average particle size and particle size distribution were measured, and the polymerization conditions and results are shown in Table 4.

[0135] Table 4

[0136]

[0137] Figure 2 and Figure 3 The electron microscope image of the polymer obtained in Example 8 is shown in the figure. The morphology of the polyethylene prepared by the catalyst of the present application is a kind of spherical shape, and the particles are very compact, which is one of the reasons for the high bulk density of the particles. The catalyst of the present application has very good prospects for industrial application.

[0138] The present application can also have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application. However, these corresponding changes and modifications should all belong to the protection scope of the claims of the present application.

Claims

1. An ultrahigh to very high molecular weight polyethylene catalyst, wherein, The active magnesium chloride without water as a carrier, and a half-metallocene binuclear titanium compound as an active component; the magnesium content in the ultra-high molecular weight polyethylene catalyst is 10-30wt%, the aluminum content is 2-4wt%, the titanium content is 2-10wt%, and the chlorine content is 30-70wt% based on 100% of the mass of the ultra-high molecular weight polyethylene catalyst; said anhydrous active magnesium chloride is an in situ active magnesium chloride having the formula (MgCl2)(R 1 MgCl) a Mg b [Ti(OR 2 )4)] c [Si(OR 3 )4] d , wherein R 1 , R 2 and R 3 are the same or different and each is independently selected from a C 1-12 alkyl group, a = 0.02 to 1, b = 0 to 0.5, c = 0 to 0.8, d = 0 to 0.8; The half-metallocene binuclear titanium compound has a structure shown in formula I, formula II or formula III: In formula I to formula III: m, n are each independently selected from 0, 1, 2, 3, 4; z, y are each independently selected from 0, 1, 2, 3, 4, 5; R1, R2, R3, R4are the same or different, each independently selected from H, C 1-20 alkyl, C 6-20 aryl, 5-20 membered heteroaryl, R a monosubstituted or polysubstituted C 1-20 alkyl, R a monosubstituted or polysubstituted C 6-20 aryl, R a monosubstituted or polysubstituted 5-20 membered heteroaryl; R is selected from the group consisting of halogen, C a each independently selected from the group consisting of halogen, C 1-20 alkyl, C 6-20 aryl, 5-20 membered heteroaryl; And / or, two adjacent R1 are connected as end groups to form a 5-20 membered heteroarylene-benzene fused ring structure with the benzene ring; And / or, two adjacent R2 are connected as end groups to form a 5-20 membered heteroarylene-benzene fused ring structure with the benzene ring; And / or, two adjacent R3 are connected as end groups to form a 5-20 membered heteroarylene-cyclopentadiene fused ring structure with the cyclopentadiene; And / or, two adjacent R4 are connected as end groups to form a 5-20 membered heteroarylene-cyclopentadiene fused ring structure with the cyclopentadiene.

2. The ultra- to very-high molecular weight polyethylene catalyst of claim 1, wherein, The half-metallocene binuclear titanium compound is selected from one or a combination of two or more of the following compounds:

3. The ultra- to very-high molecular weight polyethylene catalyst of claim 1, wherein, In the ultra-high molecular weight polyethylene catalyst, the magnesium content is 10-20wt%, the aluminum content is 2.5-3.5wt%, and the titanium content is 2-7wt%. And / or, the particle size of the ultra-high molecular weight polyethylene catalyst is 0.5μm≤D50≤3μm.

4. A preparation method of the ultra-high molecular weight polyethylene catalyst according to any one of claims 1-3, comprising the following steps: (1) mixing the active magnesium chloride without water with an alkane solvent under a protective gas atmosphere, adding an alcohol reagent, and reacting at 40-80℃ for 1-4h to obtain a modified active alcoholized magnesium chloride carrier; (2) mixing the modified active alcoholized magnesium chloride carrier obtained in step (1) with an alkane solvent under a protective gas atmosphere, cooling to -30-10℃, adding an aluminum reagent, and warming to 20-60℃ for 1-3h to obtain an activated carrier containing the aluminum reagent; (3) mixing the activated carrier containing the aluminum reagent obtained in step (2) with an alkane solvent, adding the half-metallocene binuclear titanium compound at -30-10℃, and warming to 20-50℃ for 4-8h to obtain the ultra-high molecular weight polyethylene catalyst.

5. The production method according to claim 4, wherein In step (1), the molar ratio of the alcohol reagent to the active magnesium chloride without water is 0.3-6.

6. The production method according to claim 4, wherein The alkane solvent includes C5-C30 alkanes and / or C5-C30 cycloalkanes; And / or, in step (1), the alcohol reagent includes one or a combination of two or more of C1-C10 alcohols; And / or, in step (2), the aluminum reagent includes one or a combination of two or more of dichloroethyl aluminum, diethyl aluminum chloride, triethyl aluminum, triisobutyl aluminum, ethyl aluminum sesquichloride, butyl aluminum sesquichloride, methyl aluminoxane, and modified methyl aluminoxane.

7. A catalyst system for preparing ultra-high to very-high molecular weight polyethylene, comprising the ultra-high to very-high molecular weight polyethylene catalyst of any one of claims 1-3 and a cocatalyst.

8. The ultra- to very-high molecular weight polyethylene catalyst system of claim 7, wherein, The cocatalyst comprises an organoaluminum compound R 3-b A1X b wherein X is a halogen and R is a C 1-12 alkyl group, and b is an integer from 0 to 2. and / or the molar ratio of aluminum in the cocatalyst to titanium in the ultra-high to very-high molecular weight polyethylene catalyst is 10-300.

9. A method for preparing ultra-high to very-high molecular weight polyethylene, comprising polymerization of the catalyst system of claim 7 or 8 at a temperature of 30-90°C and a pressure of 0.1-1.0 MPa.

10. Ultra-high to very-high molecular weight polyethylene prepared by the method of claim 9. The intrinsic viscosity of the ultrahigh to very high molecular weight polyethylene is 4 to 40 dl / g, the median particle size D50 is 50 to 100 μm, the particle size distribution is 0.5 to 0.8, the bulk density is ≥ 0.450 g / cm3, the ash content is < 200 ppm, and the viscosity average molecular weight is 4 to 100 million. 50 The intrinsic viscosity of the ultrahigh to very high molecular weight polyethylene is 4 to 40 dl / g, the median particle size D50 is 50 to 100 μm, the particle size distribution is 0.5 to 0.8, the bulk density is ≥ 0.450 g / cm3, the ash content is < 200 ppm, and the viscosity average molecular weight is 4 to 100 million. 3 The intrinsic

Images