Polyethylene wax and preparation method thereof

Abstract

The invention discloses polyethylene wax and a preparation method thereof, a solvent a, a co-catalyst b and a main catalyst c are sequentially added into a reaction kettle, then an ethylene polymerization monomer is introduced, a polymerization reaction is performed, a terminator d is added after the full reaction to obtain a wax-like substance, and the wax-like substance is filtered, washed and dried to obtain narrow-distribution polyethylene wax, the main catalyst is a non-metallocene catalyst and has the following general formula structure: # imgabs0 #, M is selected from one of transition metal atoms from group IIIB to group IB in the periodic table of elements, preferably one of transition metal atoms from group IVB, and more preferably Ti or Zr; x and X'are respectively and independently selected from O, S and NH, L and L 'are selected from halogen atoms, preferably Cl or Br, and R1, R2, R3, R' 1, R '2 and R' 3 are respectively and independently selected from hydrogen, substituted or unsubstituted C1-C12 aliphatic hydrocarbon groups, C6-C12 aromatic hydrocarbon groups, oxygen-containing groups, nitrogen-containing groups, sulfur-containing groups or halogen atoms.

Description

Technical Field

[0001] The invention belongs to the technical field of polyethylene wax preparation, and specifically relates to polyethylene wax and a preparation method thereof. Background Art

[0002] Polyethylene wax (PE wax), also known as polymer wax. It has the appearance of white small micro beads / flakes, and has the characteristics of low viscosity, high melting point, high hardness, high gloss, and snow-white color. In particular, its softening point is high (above 100°C), close to that of polymer polyethylene. Polyethylene wax is a polyethylene copolymer with a molecular weight between 1000 and 5000. It has good cold resistance, heat resistance, chemical resistance and wear resistance, making it a widely used chemical material. Polyethylene wax has high added value and high production cost. At present, the production volume of polyethylene wax in my country is far from meeting the market demand. Most of it relies on foreign imports and is expensive. In normal production, this part of wax can be directly added to polyolefin processing as an additive, which can increase the gloss and processing performance of the product. As a lubricant, it has stable chemical properties and good electrical properties. Polyethylene wax has good compatibility with polyethylene, polypropylene, polyvinyl wax, ethylene propylene rubber, and butyl rubber, and can improve the fluidity of polyethylene, polypropylene, ABS and the demoulding properties of polymethyl methacrylate and polycarbonate. Compared with PVC and other external lubricants, polyethylene wax has a stronger internal lubrication effect. In addition, polyethylene wax is non-toxic, has good thermal stability, and low volatility at high temperatures. It can be widely used in the manufacture of masterbatches, plastic steel, PVC pipes, hot melt adhesives, rubber, shoe polish, leather brighteners, cable insulation materials, floor wax, coatings, inks, cosmetics and other fields. In some applications, polyethylene wax can also replace petroleum wax, natural wax and other synthetic waxes.

[0003] According to different preparation methods, polyethylene wax can be divided into three types of polyethylene wax: polymerization type, cracking type and by-product type. Polymerized polyethylene wax refers to the product generated when ethylene is polymerized, while cracking type polyethylene wax is formed by heating and cracking polyethylene resin. At present, there are only two production methods for polyethylene wax in my country: cracking method and by-product produced when polyethylene is produced. Cracking polyethylene wax uses high molecular weight polyethylene as the main raw material, adds other auxiliary materials, and is made through a series of depolymerization reactions. By-product type polyethylene wax comes from a small amount of oligomers, namely polyethylene wax, produced during the start-up and shutdown process of polyethylene production. However, due to its low purity, wide molecular weight distribution and low melting temperature, its application is severely limited, so its application range is narrow, the selling price is low, and the added value of the product is low. Since the molecular weight distribution of both cracking type and by-product type polyethylene wax is relatively wide, and there are certain differences in their molecular structures, their application occasions are different. The molecular weight distribution affects the mechanical properties of polyethylene wax, while the molecular structure affects the crystallization properties of polyethylene wax. The most important thing is that the molecular weight distribution is too wide to meet the needs of high-end masterbatch, high-end automotive paint, high-end coating matting agent and other products. In addition, the preparation of polyethylene wax by the cracking method and the by-product method must be carried out under high temperature and high pressure conditions, with high energy consumption, low production efficiency, complex operation, and difficulty in continuous experiments, and low economic benefits of expanding scale industrial production.

[0004] Therefore, my country is in urgent need of a preparation method for producing polyethylene wax with a narrow molecular weight distribution and simple and controllable operating conditions.

[0005] Patent CN113563498A discloses a method for producing polyethylene wax, wherein diethyl zinc and a catalyst are added to a reaction vessel; then hydrogen and ethylene are introduced for polymerization to obtain polyethylene wax. Alternatively, a ZN catalyst and an organic aluminum compound as a co-catalyst are added to a reaction vessel; then hydrogen and ethylene are introduced for polymerization to obtain polyethylene wax. By using the catalyst prepared by the present invention to polymerize ethylene and hydrogen, polyethylene wax with adjustable molecular weight distribution and excellent quality can be prepared with high activity; however, the molecular weight distribution of the polyethylene wax product prepared by this method is relatively wide; the experimental raw materials use metallocene catalysts and hydrogen, which is not easy to operate and has high economic costs.

[0006] Patent CN113698512A discloses a polyethylene cracking preparation method for polyethylene wax, which belongs to the technical field of polyethylene wax. The polyethylene cracking preparation method for polyethylene wax includes the following steps: step 1, raw material preparation, mixing polyethylene material and waste recycled polyethylene material to obtain a polyethylene mixture, and then preparing to pretreat the Fischer-Tropsch refined wax, and all raw materials are dried and set aside. The polyethylene cracking preparation method for polyethylene wax can realize the reaction basis for the preparatory cracking of polyethylene through the Fischer-Tropsch refined wax, realize the stable heating and decomposition of polyethylene, and through the Fischer-Tropsch refined wax and the heated argon gas, it can realize the subsequent heating of the Fischer-Tropsch refined wax that needs to be heated, and reduce the energy consumption ratio. Under the premise of ensuring the efficiency of production and reducing the difficulty of production, the waste heat is then used for heating to reduce the production heat required for the next batch of polyethylene wax; the molecular weight distribution of the polyethylene wax prepared by this method is still large, the experimental conditions are high temperature and high pressure, the energy consumption is high, and the economic benefit is low. Summary of the invention

[0007] The purpose of the present invention is to provide a polyethylene wax and a preparation method thereof. The polyethylene wax with narrow distribution is synthesized under low temperature and low pressure conditions by using an ethylene polymerization method, and the prepared polyethylene wax has high purity, narrow molecular weight distribution, and high melting temperature, and the production cost is significantly reduced compared with the commonly used cracking method and by-product method in China, and the energy utilization efficiency is improved.

[0008] To achieve the above object, the present invention provides a method for preparing polyethylene wax, wherein a solvent a, a co-catalyst b and a main catalyst c are added to a reaction kettle in sequence, and then ethylene polymerization monomers are introduced to carry out polymerization reaction, and after sufficient reaction, a terminator d is added to obtain a waxy substance, and the waxy substance is filtered, washed, and dried to obtain a narrow distribution polyethylene wax, wherein the main catalyst is a non-metallocene catalyst and has the following general structure:

[0009]

[0010] Wherein, M is selected from one of the transition metal atoms of Group IIIB to Group IB of the Periodic Table, preferably one of the transition metal atoms of Group IVB, more preferably Ti or Zr;

[0011] X and X' are each independently selected from O, S and NH;

[0012] L, L' are selected from halogen atoms, preferably Cl or Br;

[0013] R1, R2, R3, R'1, R'2, and R'3 are each independently selected from hydrogen, substituted or unsubstituted C1-C 12 Aliphatic hydrocarbon groups, C6~C 12 Aromatic hydrocarbon group, oxygen-containing group, nitrogen-containing group, sulfur-containing group or halogen atom.

[0014] In the method for preparing polyethylene wax of the present invention, the non-metallocene catalyst has one of the following structures:

[0015] M=Ti, X=X'=O, L=L'=Cl, R1=R2=R3=H, R'1=R'2=R'3=H;

[0016] M=Ti, X=X'=O, L=L'=Cl, R1=R2=R3=CH3, R'1=R'2=R'3=CH3;

[0017] M=Ti, X=X'=O, L=L'=Cl, R1=R3=CH3, R2=H, R'1=R'3=CH3, R'2=H;

[0018] M=Ti, X=X'=O, L=L'=Cl, R3=CH3, R1=R2=H, R'3=CH3, R'1=R'2=H;

[0019] M=Ti, X=X'=O, L=L'=Cl, R1=R2=H, R3=Cl, R'1=R'2=H, R'3=Cl;

[0020] M=Ti, X=X'=O, L=L'=Cl, R1=R2=R3=Cl, R'1=R'2=R'3=Cl;

[0021] M=Ti, X=X'=O, L=L'=Cl, R1=i-Bu, R2=R3=H; R'1=i-Bu, R'2=R'3=H;

[0022] M=Ti, X=X'=O, L=L'=Cl, R1=R3=i-Bu, R2=H; R'1=R'3=i-Bu, R'2=H;

[0023] M=Ti,

[0024] CH3;

[0025] M=Ti, X=X'=NH, L=L'=Cl, R1=R2=R3=H, R'1=R'2=R'3=H;

[0026] M=Ti, X=X'=NH, L=L'=Cl, R1=R2=R3=CH3, R'1=R'2=R'3=CH3;

[0027] M=Ti,X=X’=NH,L=L’=Cl,R1=R3=CH3,R2=H,R’1=R’3=CH3,R’2=H;

[0028] M=Ti,X=X’=NH,L=L’=Cl,R3=CH3,R1=R2=H,R’3=CH3,R’1=R’2=H;

[0029] M=Ti,X=X’=NH,L=L’=Cl,R1=R2=H,R3=Cl,R’1=R’2=H,R’3=Cl;

[0030] M=Ti,X=X’=NH,L=L’=Cl,R1=R2=R3=Cl,R’1=R’2=R’3=Cl;

[0031] M=Ti,X=X’=NH,L=L’=Cl,R1=i-Bu,R2=R3=H;R’1=i-Bu,R’2=R’3=H;

[0032] M=Ti,X=X’=NH,L=L’=Cl,R1=R3=i-Bu,R2=H;R’1=R’3=i-Bu,R’2=H;

[0033] M=Ti,X=X’=NH,L=L’=Cl,R1=i-Bu,R2=H,R3=CH3;R’1=i-Bu,R’2=H,R’3=

[0034] CH3;

[0035] M=Ti,X=X’=O,L=L’=Cl,R3=OCH3,R1=R2=H,R’3=OCH3,R’1=R’2=H;

[0036] M=Ti,X=X’=O,L=L’=Cl,R1=R2=OCH3,R3=Cl,R’1=R’2=OCH3,R’3=Cl;

[0037] M=Ti,X=X’=O,L=L’=Cl,R1=R2=R3=OCH3,R’1=R’2=R’3=OCH3;

[0038] M=Ti,X=X’=O,L=L’=Cl,R1=OBu,R2=R3=H;R’1=OBu,R’2=R’3=H;

[0039] M=Ti,X=X’=O,L=L’=Cl,R1=R3=OBu,R2=H;R’1=R’3=OBu,R’2=H;

[0040] M=Ti,

[0041] CH3;

[0042] M=Ti, X=X'=NH, L=L'=Cl, R1=R2=R3=OCH3, R'1=R'2=R'3=OCH3;

[0043] M=Ti, X=X'=NH, L=L'=Cl, R1=R2=R3=OBu, R'1=R'2=R'3=OBu;

[0044] M=Ti,

[0045] M=Ti, X=X'=NH, L=L'=Cl, R3=OCH3, R1=R2=H, R'3=OCH3, R'1=R'2=H;

[0046] M=Ti, X=X'=NH, L=L'=Cl, R1=R2=H, R3=OCH3, R'1=R'2=H, R'3=OCH3.

[0047] In the method for preparing polyethylene wax of the present invention, the non-metallocene catalyst is prepared by the following method:

[0048] S1, dissolving a biaryl ligand containing nitrogen, oxygen or sulfur heteroatoms in an organic solvent to obtain a component A solution;

[0049] S2, dissolving a compound containing one of the transition metal atoms from Group IIIB to Group IB in an organic solvent to obtain a component B solution;

[0050] S3, adding the component B solution dropwise to the component A solution at a temperature of 0°C to 50°C under stirring, and refluxing at a constant temperature of 50°C to 120°C for 1h to 4h;

[0051] S4, under argon environment, cool the reaction system to 0°C to 30°C, and stir the reaction for 12h to 48h;

[0052] S5, distilling the liquid in the reaction system under reduced pressure to obtain a viscous solid, washing it with an organic solvent, filtering it, and drying it to obtain a powdered solid catalyst.

[0053] In the preparation method of polyethylene wax described in the present invention, the biaryl ligand containing nitrogen, oxygen or sulfur heteroatoms is substituted or unsubstituted biphenol or benzidine, preferably 2,2'-biphenol; the compound containing one of the transition metal atoms from Group IIIB to Group IB is the chloride or bromide of the metal, preferably titanium tetrachloride; the organic solvent is one or more of toluene, dichloromethane, tetrahydrofuran, n-hexane and n-heptane, preferably toluene.

[0054] In the method for preparing polyethylene wax of the present invention, the molar ratio of the biaryl ligand to the compound containing one of the transition metal atoms from Group IIIB to Group IB is 1:0.8 to 1:1.2.

[0055] In the method for preparing polyethylene wax of the present invention, the solvent a is one or more of benzene, toluene, o-xylene, n-hexane, n-heptane and cyclohexane, preferably toluene.

[0056] The preparation method of polyethylene wax of the present invention, the cocatalyst b is an alkyl aluminum, the alkyl aluminum is one or more of triethyl aluminum, diethyl aluminum monochloride, ethyl aluminum dichloride, sesquiethyl aluminum, diisobutyl aluminum dichloride, triisobutyl aluminum, diisopropyl aluminum monochloride, methyl n-propyl aluminum monochloride and diphenyl aluminum monochloride, preferably semi-ethyl aluminum chloride, the cocatalyst b is added in a solution with a mass concentration of 10% to 50%, and the solvent of the solution is selected from one or more of cyclohexane, toluene, and isoparaffin solvent oil, preferably toluene.

[0057] In the method for preparing polyethylene wax of the present invention, the terminator d is one or more of water, acids, alcohols and organic amines, preferably one or more of hydrochloric acid, ethanol and octanol.

[0058] In the method for preparing polyethylene wax of the present invention, the polymerization reaction temperature is 50-110°C, preferably 65-100°C, and the reaction time is 5-300 minutes, preferably 5-180 minutes.

[0059] The preparation method of polyethylene wax of the present invention comprises the following steps: the amount of solvent a is 10% to 100% of the volume of the reactor, preferably 20% to 60%, the pressure of ethylene introduction is 0.1 to 3 MPa, preferably 1 to 3 MPa, the weight ratio of solvent a to main catalyst c is 10 3 ~10 6 , preferably 10 4 ~10 5 The weight ratio of the solvent a to the co-catalyst b is 5×10 3 ~10 4 , preferably 5×10 3 ~10 3 .

[0060] To achieve the above object, the present invention further provides a polyethylene wax, wherein the average molecular weight of the polyethylene wax is 1500 to 2500 g / mol, and the polymer dispersibility index PDI is 1.5 to 3.0.

[0061] Beneficial effects of the present invention:

[0062] (1) The molecular weight of the narrow distribution polyethylene wax of the present invention is 1500 to 3000 g / mol, the molecular weight distribution is narrow, the PDI can be about 1.5, and it has good lubricity, processability and metal pigment positioning properties.

[0063] (2) The preparation method of the narrow distribution polyethylene wax provided by the present invention has high catalytic activity, and the catalytic activity can reach 6.21-13.75 KgPE (g.cat·h) -1 The crystallinity is 72-95%, the wax obtained has good morphology, the method is simple, easy and stable, no paddle sticking or wall sticking phenomenon is observed, it is convenient to implement continuous experiments, and it is suitable for industrial production. DETAILED DESCRIPTION

[0064] The present invention is described in detail below by way of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention.

[0065] In the present invention, the reactor can be a conventional reactor used in the art, such as a reactor with a stirring device and controllable temperature and pressure. All operations in the present invention can adopt standard Schlenk technology.

[0066] In the present invention, PDI (Polymer dispersity index) is a polymer dispersity index used to describe the molecular weight distribution of a polymer. The ratio of the weight average molecular weight to the number average molecular weight is called the polymer dispersity index.

[0067] Source of raw materials or equipment: The following raw materials are all industrial grade; glove box; α-olefin catalyst evaluation device; electronic balance; vacuum pump; oven

[0068] Evaluation and analysis methods:

[0069] (1) Gel Permeation Chromatography (GPC)

[0070] 8mg of sample was dissolved in 8ml of 1,2,4-trichlorobenzene at 160°C for 90 minutes. Then, 200μl of sample solution was injected into a high temperature GPC with an IR5 infrared detector (Polymer Char, Spain) at a flow rate of 0.5ml / min, 145°C in the column area and 160°C in the detector area. Data was processed by GPC software (Polymer Char, Spain). The weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) in g / mol were analyzed by gel permeation chromatography (GPC). Molecular weight distribution (PDI) was calculated by Mw / Mn.

[0071] (2) Differential Scanning Calorimeter (DSC)

[0072] First, the temperature is raised to eliminate the thermal history, then the temperature is lowered, and finally the melting point obtained in the second melting process is taken as the measurement value.

[0073] (3) Characterization of polymer density

[0074] The test was conducted using the density gradient method according to ASTM D1505 98.

[0075] The following examples were carried out under anhydrous and oxygen-free conditions. Before adding the reactants, the reactor was replaced with nitrogen and ethylene gases respectively. The organic solvent is an organic solvent that has been anhydrous. The anhydrous treatment of the organic solvent can refer to the anhydrous treatment method of organic solvents commonly used in the art, such as soaking the activated molecular sieve for adsorption and dehydration, and the molecular sieve soaking amount is preferably 1 / 3 of the organic solvent to be treated.

[0076] Example 1

[0077] Under nitrogen atmosphere, weigh 186 mg of 2,2'-biphenol and add it to a 100 ml Schlenk bottle, add 30 ml of toluene, stir for 5 to 10 min until it is completely dissolved to form an anhydrous transparent solution A; under nitrogen atmosphere, take 189.7 mg of titanium tetrachloride and add it to a 50 ml round-bottom flask, add 20 ml of toluene, stir for 5 to 10 min until it is completely dissolved to form an anhydrous transparent solution B; under stirring, at a temperature of 0°C, slowly add solution B dropwise into solution A, after the addition is complete, stir for 10 min until it is completely dissolved, heat to 60°C, stir and reflux for reaction for 3 h; then cool to 20°C and stir for reaction for 24 h, remove the solvent by distillation under reduced pressure, separate the product, wash the product with n-hexane 3 times, and dry it to obtain an orange-yellow solid powder catalyst.

[0078] The non-metallocene catalyst was designated as CAT-1. 1H-NMR (CDCl3, 300 MHz): 6.98-7.10 (8 Haromatic protons).

[0079] Example 2

[0080] Under nitrogen atmosphere, weigh 186 mg of 2,2'-biphenol and add it to a 100 ml Schlenk bottle, add 30 ml of toluene, stir for 5 to 10 min until it is completely dissolved to form an anhydrous transparent solution A; under nitrogen atmosphere, take 245 mg of zirconium tetrachloride and add it to a 50 ml round-bottom flask, add 20 ml of toluene, stir for 5 to 10 min until it is completely dissolved to form an anhydrous transparent solution B; under stirring, at a temperature of 10°C, slowly add solution B dropwise into solution A, after the addition is completed, stir for 10 min until it is completely dissolved, heat to 80°C, stir and reflux for reaction for 3 h; then cool to 30°C, stir and react for 18 h, remove the solvent by distillation under reduced pressure, separate the product, wash the product with n-hexane 3 times, and dry it to obtain an orange-yellow solid powder catalyst.

[0081] The non-metallocene catalyst was recorded as CAT-2. 1H-NMR (CDCl3, 300 MHz): 7.10-7.31 (8 Haromatic protons).

[0082] Example 3

[0083] Under nitrogen atmosphere, weigh 150 mg of 3,3'-dimethoxybiphenol and add it to a 100 ml Schlenk bottle, add 50 ml of toluene, stir for 5 to 10 min until it is completely dissolved to form an anhydrous transparent solution A; under nitrogen atmosphere, take 300 mg of hafnium tetrachloride and add it to a 50 ml round-bottom flask, add 20 ml of toluene, stir for 5 to 10 min until it is completely dissolved to form an anhydrous transparent solution B; under stirring, at a temperature of 50°C, slowly add solution B dropwise into solution A, after the addition is completed, stir for 10 min until it is completely dissolved, heat to 100°C, stir and reflux for reaction for 3 h; then cool to 0°C and stir for reaction for 40 h, remove the solvent by distillation under reduced pressure, separate the product, wash the product with n-hexane 3 times, and dry it to obtain an orange-yellow solid powder catalyst.

[0084] The non-metallocene catalyst was recorded as CAT-3. 1H-NMR (CDCl3, 300 MHz): 7.12-7.20 (6 Haromatic protons), 3.74 (6 H, -OMe).

[0085] Example 4

[0086] Under nitrogen atmosphere, weigh 2,2'-benzidine (1mmol, 184mg) and add it to a 100ml Schlenk bottle, add 30ml toluene, stir for 5-10min until completely dissolved, and form an anhydrous transparent solution A; under nitrogen atmosphere, take 195mg titanium tetrachloride and add it to a 50ml round-bottom flask, add 20ml n-heptane, stir for 5-10min until completely dissolved, and form an anhydrous transparent solution B; under stirring, at a temperature of 10°C, slowly add solution B dropwise into solution A, after the addition is complete, stir for 10min until completely dissolved, heat to 100°C, stir and reflux for reaction for 1h; then cool to 20°C and stir for reaction for 24h, remove the solvent by distillation under reduced pressure, separate the product, wash the product with n-hexane 3 times, and dry it to obtain an orange-yellow solid powder catalyst.

[0087] The non-metallocene catalyst was designated as CAT-4. 1H-NMR (CDCl 3 , 300 MHz): 7.02–7.11 (8 Haromatic protons).

[0088] Example 5

[0089] Under nitrogen atmosphere, weigh 317 mg of 3,3'-dimethoxybenzidine and add it to a 100 ml Schlenk bottle, add 30 ml of toluene, stir for 5 to 10 min until it is completely dissolved to form an anhydrous transparent solution A; under nitrogen atmosphere, take 289.7 mg of zirconium tetrachloride and add it to a 50 ml round-bottom flask, add 20 ml of n-hexane, stir for 5 to 10 min until it is completely dissolved to form an anhydrous transparent solution B; under stirring, at a temperature of 0°C, slowly add solution B dropwise into solution A, after the addition is complete, stir for 10 min until it is completely dissolved, heat to 60°C, stir and reflux for reaction for 3 h; then cool to 20°C and stir for reaction for 24 h, remove the solvent by distillation under reduced pressure, separate the product, wash the product with n-hexane 3 times, and dry it to obtain an orange-yellow solid powder catalyst.

[0090] The non-metallocene catalyst was designated as CAT-5. 1H-NMR (CDCl3, 300 MHz): 7.15-7.29 (6 Haromatic protons), 3.72 (6 H, -OMe).

[0091] Example 6

[0092] Under nitrogen atmosphere, weigh 2,2'-dimethylbenzidine (1mmol, 285mg) and add it to a 100ml Schlenk bottle, add 30ml toluene, stir for 5-10min until completely dissolved, and form an anhydrous transparent solution A; under nitrogen atmosphere, take titanium tetrachloride (1mmol, 189.7mg) and add it to a 50ml round-bottom flask, add 20ml toluene, stir for 5-10min until completely dissolved, and form an anhydrous transparent solution B; under stirring, at a temperature of 0℃, slowly add solution B dropwise into solution A, after the addition is complete, stir for 10min until completely dissolved, heat to 80℃, stir and reflux for reaction for 3h; then cool to 20℃ and stir for reaction for 48h, remove the solvent by distillation under reduced pressure, separate the product, wash the product with n-hexane 3 times, and dry it to obtain an orange-yellow solid powder catalyst.

[0093] The non-metallocene catalyst was designated as CAT-6. 1H-NMR (CDCl3, 300 MHz): 7.08-7.23 (6 Haromatic protons), 2.32 (6 H, -Me).

[0094] Example 7

[0095] Under nitrogen atmosphere, weigh 2,2'-dimethylbiphenol (1mmol, 287mg) and add it to a 100ml Schlenk bottle, add 30ml toluene, stir for 5-10min until completely dissolved, and form an anhydrous transparent solution A; under nitrogen atmosphere, take titanium tetrachloride (1mmol, 189.7mg) and add it to a 50ml round-bottom flask, add 20ml toluene, stir for 5-10min until completely dissolved, and form an anhydrous transparent solution B; under stirring, at a temperature of 0℃, slowly add solution B dropwise into solution A, after the addition is complete, stir for 10min until completely dissolved, heat to 50℃, stir and reflux for 4h; then cool to 20℃ and stir for 12h, remove the solvent by distillation under reduced pressure, separate the product, wash the product with n-hexane 3 times, and dry it to obtain an orange-yellow solid powder catalyst.

[0096] The non-metallocene catalyst was designated as CAT-7. 1H-NMR (CDCl3, 300 MHz): 7.05–7.13 (6 Haromatic protons), 2.34 (6 H, -Me).

[0097] Example 8

[0098] Under nitrogen atmosphere, weigh 3,3'-dimethoxybiphenol (1mmol, 319mg) and add it to a 100ml Schlenk bottle, add 30ml toluene, stir for 5-10min until completely dissolved, and form an anhydrous transparent solution A; under nitrogen atmosphere, take titanium tetrachloride (1mmol, 189.7mg) and add it to a 50ml round-bottom flask, add 20ml toluene, stir for 5-10min until completely dissolved, and form an anhydrous transparent solution B; under stirring, at a temperature of 0℃, slowly add solution B dropwise into solution A, after the addition is complete, stir for 10min until completely dissolved, heat to 120℃, stir and reflux for 3h; then cool to 20℃ and stir for 36h, remove the solvent by distillation under reduced pressure, separate the product, wash the product with n-hexane 3 times, and dry it to obtain an orange-yellow solid powder catalyst.

[0099] The non-metallocene catalyst was designated as CAT-8. 1H-NMR (CDCl3, 300 MHz): 7.10–7.28 (6 Haromatic protons), 3.75 (6 H, -OMe).

[0100] Example 9

[0101] In a 1L reactor of an α-olefin catalyst evaluation device, the temperature was raised to preheat the reactor to reach the reaction temperature, and the reactor with magnetic stirring and temperature control was replaced 3 times with nitrogen and ethylene gas respectively. 20% of the volume of the reactor volume of toluene solvent was added to the reactor, the amount of sesquiethylaluminum chloride was 0.005 of the weight of toluene, the amount of main catalyst CAT-1 was 0.00003 of the weight of toluene, ethylene gas was introduced, and the ethylene pressure was controlled to be 2MPa. After stirring and reacting at 90°C and 300rpm for 0.5h, ethylene was discharged to make the pressure in the reactor return to normal pressure, and after collecting the polymer, 5% hydrochloric acid-ethanol solution was added to terminate the reaction. The polymer was allowed to stand overnight, filtered three times with 5% hydrochloric acid-ethanol solution, and the filter cake was washed with deionized water until neutral, and dried at 100°C to constant weight to obtain narrow distribution polyethylene wax L1.

[0102] Example 10

[0103] In a 1L reactor of an α-olefin catalyst evaluation device, the temperature was raised to preheat the reactor to reach the reaction temperature, and the reactor with magnetic stirring and temperature control was replaced 3 times with nitrogen and ethylene gas respectively. 20% of the volume of the reactor was added to the reactor as cyclohexane solvent, the amount of sesquiethylaluminum chloride was 0.005 of the weight of cyclohexane, the amount of the main catalyst CAT-2 was 0.00002 of the weight of toluene, ethylene gas was introduced, and the ethylene pressure was controlled to be 2MPa. After stirring and reacting at 80°C and 300rpm for 0.5h, the ethylene was discharged to make the pressure in the reactor return to normal pressure, and after collecting the polymer, a 5% hydrochloric acid-ethanol solution was added to terminate the reaction. The polymer was allowed to stand overnight, filtered three times with a 5% hydrochloric acid-ethanol solution, and the filter cake was washed with deionized water until neutral, and dried at 100°C to constant weight to obtain a narrow distribution polyethylene wax L2.

[0104] Embodiment 11

[0105] In a 1L reactor of an α-olefin catalyst evaluation device, the temperature was raised to preheat the reactor to reach the reaction temperature, and the reactor with magnetic stirring and temperature control was replaced 3 times with nitrogen and ethylene gas respectively. 20% of the volume of the reactor volume of toluene solvent was added to the reactor, the amount of dimethylaluminum chloride was 0.003 of the weight of toluene, the amount of main catalyst CAT-3 was 0.00003 of the weight of toluene, ethylene gas was introduced, and the ethylene pressure was controlled to be 2MPa. After stirring and reacting at 95°C and 300rpm for 0.5h, ethylene was discharged to make the pressure in the reactor return to normal pressure, and after collecting the polymer, 5% hydrochloric acid-ethanol solution was added to terminate the reaction. The polymer was allowed to stand overnight, filtered three times with 5% hydrochloric acid-ethanol solution, and the filter cake was washed with deionized water until neutral, and dried at 100°C to constant weight to obtain narrow distribution polyethylene wax L3.

[0106] Example 12

[0107] In a 1L reactor of an α-olefin catalyst evaluation device, the temperature was raised to preheat the reactor to reach the reaction temperature, and the reactor with magnetic stirring and temperature control was replaced 3 times with nitrogen and ethylene gas respectively. 20% of the volume of the reactor volume of toluene solvent was added to the reactor, the amount of dimethylaluminum chloride was 0.002 of the weight of toluene, the amount of main catalyst CAT-4 was 0.00003 of the weight of toluene, ethylene gas was introduced, and the ethylene pressure was controlled to be 1.5MPa. After stirring and reacting at 85°C and 300rpm for 0.5h, the ethylene was discharged to make the pressure in the reactor return to normal pressure, and after collecting the polymer, a 5% hydrochloric acid-ethanol solution was added to terminate the reaction. The polymer was allowed to stand overnight, filtered three times with a 5% hydrochloric acid-ethanol solution, and the filter cake was washed with deionized water until neutral, and dried at 100°C to constant weight to obtain a narrow distribution polyethylene wax L4.

[0108] Example 13

[0109] In a 1L reactor of an α-olefin catalyst evaluation device, the temperature was raised to preheat the reactor to reach the reaction temperature, and the reactor with magnetic stirring and temperature control was replaced 3 times with nitrogen and ethylene gas respectively. 20% of the volume of the reactor volume of toluene solvent was added to the reactor, the amount of sesquiethylaluminum chloride was 0.003 of the weight of toluene, the amount of main catalyst CAT-5 was 0.00003 of the weight of toluene, ethylene gas was introduced, and the ethylene pressure was controlled to be 1MPa. After stirring and reacting at 75°C and 300rpm for 1h, ethylene was discharged to make the pressure in the reactor return to normal pressure, and after collecting the polymer, 5% hydrochloric acid-octanol solution was added to terminate the reaction. The polymer was allowed to stand overnight, filtered three times with 5% hydrochloric acid-octanol solution, and the filter cake was washed with deionized water until neutral, and dried at 100°C to constant weight to obtain narrow distribution polyethylene wax L5.

[0110] Embodiment 14

[0111] In a 1L reactor of an α-olefin catalyst evaluation device, the temperature was raised to preheat the reactor to reach the reaction temperature, and the reactor with magnetic stirring and temperature control was replaced 3 times with nitrogen and ethylene gas respectively. 25% of the volume of the reactor was added to the reactor as a xylene solvent, the amount of sesquiethylaluminum chloride was 0.0028 of the weight of xylene, and the amount of the main catalyst CAT-6 was 0.000025 of the weight of xylene. Ethylene gas was introduced and the ethylene pressure was controlled to be 2.5 MPa. After stirring and reacting at 90°C and 300rpm for 2h, the ethylene was discharged to make the pressure in the reactor return to normal pressure. After collecting the polymer, a 10% aqueous hydrochloric acid solution was added to terminate the reaction. The polymer was allowed to stand overnight and filtered three times with a 10% hydrochloric acid-ethanol solution. The filter cake was washed with deionized water until neutral and dried at 100°C to constant weight to obtain a narrow distribution polyethylene wax L6.

[0112] Embodiment 15

[0113] In a 1L reactor of an α-olefin catalyst evaluation device, the temperature was raised to preheat the reactor to reach the reaction temperature, and the reactor with magnetic stirring and temperature control was replaced 3 times with nitrogen and ethylene gas respectively. 20% of the volume of the reactor was added to the reactor. The amount of triethylaluminum was 0.003 of the weight of n-hexane, and the amount of main catalyst CAT-7 was 0.00003 of the weight of n-hexane. Ethylene gas was introduced and the ethylene pressure was controlled to be 1MPa. After stirring and reacting at 100°C and 300rpm for 1.5h, the ethylene was discharged to make the pressure in the reactor return to normal pressure. After collecting the polymer, 10% hydrochloric acid-octanol solution was added to terminate the reaction. The polymer was allowed to stand overnight and filtered three times with 10% hydrochloric acid-ethanol solution. The filter cake was washed with deionized water until neutral and dried at 100°C to constant weight to obtain narrow distribution polyethylene wax L7.

[0114] Example 16

[0115] In a 1L reactor of an α-olefin catalyst evaluation device, the temperature was raised to preheat the reactor to reach the reaction temperature, and the reactor with magnetic stirring and temperature control was replaced 3 times with nitrogen and ethylene gas respectively. 20% of the volume of the reactor was added to the reactor. The amount of triisobutylaluminum was 0.002 of the weight of dichloromethane, and the amount of the main catalyst CAT-8 was 0.00003 of the weight of toluene. Ethylene gas was introduced and the ethylene pressure was controlled to be 1.5MPa. After stirring and reacting at 95°C and 300rpm for 3h, the ethylene was discharged to make the pressure in the reactor return to normal pressure. After collecting the polymer, an ethanol solution was added to terminate the reaction. The polymer was allowed to stand overnight and filtered three times with an ethanol solution. The filter cake was washed with deionized water until neutral and dried at 100°C to constant weight to obtain narrow distribution polyethylene wax L8.

[0116] Embodiment 17

[0117] In a 1L reactor of an α-olefin catalyst evaluation device, the temperature was raised to preheat the reactor to reach the reaction temperature, and the reactor with magnetic stirring and temperature control was replaced 3 times with nitrogen and ethylene gas respectively. 23% of the volume of the reactor was added to the reactor as n-heptane solvent, the amount of dipropylaluminum monochloride was 0.003 of the weight of n-heptane, and the amount of the main catalyst CAT-8 was 0.000025 of the weight of n-heptane. Ethylene gas was introduced and the ethylene pressure was controlled to be 3MPa. After stirring and reacting at 100°C and 300rpm for 0.5h, the ethylene was discharged to make the pressure in the reactor return to normal pressure. After collecting the polymer, a 5% hydrochloric acid-ethanol solution was added to terminate the reaction. The polymer was allowed to stand overnight and filtered three times with a 5% hydrochloric acid-ethanol solution. The filter cake was washed with deionized water until neutral and dried at 100°C to constant weight to obtain narrow distribution polyethylene wax L9.

[0118] Embodiment 18

[0119] In a 1L reactor of an α-olefin catalyst evaluation device, the temperature was raised to preheat the reactor to reach the reaction temperature, and the reactor with magnetic stirring and temperature control was replaced 3 times with nitrogen and ethylene gas respectively. 20% of the volume of the reactor was added to the reactor as cyclooctane solvent, the amount of sesquiethylaluminum chloride was 0.003 of the weight of cyclooctane, and the amount of the main catalyst CAT-8 was 0.00002 of the weight of cyclooctane. Ethylene gas was introduced and the ethylene pressure was controlled to be 0.5MPa. After stirring and reacting at 80°C and 300rpm for 2h, ethylene was discharged to make the pressure in the reactor return to normal pressure. After collecting the polymer, 10% hydrochloric acid-ethanol solution was added to terminate the reaction. The polymer was allowed to stand overnight and filtered three times with 10% hydrochloric acid-ethanol solution. The filter cake was washed with deionized water until neutral and dried at 100°C to constant weight to obtain narrow distribution polyethylene wax L10.

[0120] The molecular weight distribution, softening point and density of the polyethylene waxes L1-L10 prepared in Examples 9 to 18 were measured by gel permeation chromatography, differential scanning calorimetry and density gradient method. The specific results are shown in Table 1.

[0121] Table 1 Characterization results of polyethylene wax

[0122]

[0123] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing polyethylene wax, characterized in that: Solvent a, co-catalyst b and main catalyst c are added to the reactor in sequence, and then ethylene polymerization monomer is introduced to carry out polymerization reaction. After sufficient reaction, terminator d is added to obtain a waxy substance, and the waxy substance is filtered, washed, and dried to obtain a narrow distribution polyethylene wax, wherein the main catalyst is a non-metallocene catalyst and has the following general structure: Wherein, M is selected from one of the transition metal atoms of Group IIIB to Group IB of the Periodic Table, preferably one of the transition metal atoms of Group IVB, more preferably Ti or Zr; X and X' are each independently selected from O, S and NH; L, L' are selected from halogen atoms, preferably Cl or Br; R1, R2, R3, R'1, R'2, and R'3 are each independently selected from hydrogen, substituted or unsubstituted C1-C 12 Aliphatic hydrocarbon groups, C6~C 12 Aromatic hydrocarbon group, oxygen-containing group, nitrogen-containing group, sulfur-containing group or halogen atom.

2. The method for preparing polyethylene wax according to claim 1, characterized in that: The non-metallocene catalyst has one of the following structures: M=Ti, X=X'=O, L=L'=Cl, R1=R2=R3=H, R'1=R'2=R'3=H; M=Ti, X=X'=O, L=L'=Cl, R1=R2=R3=CH3, R'1=R'2=R'3=CH3; M=Ti, X=X'=O, L=L'=Cl, R1=R3=CH3, R2=H, R'1=R'3=CH3, R'2=H; M=Ti, X=X'=O, L=L'=Cl, R3=CH3, R1=R2=H, R'3=CH3, R'1=R'2=H; M=Ti, X=X'=O, L=L'=Cl, R1=R2=H, R3=Cl, R'1=R'2=H, R'3=Cl; M=Ti, X=X'=O, L=L'=Cl, R1=R2=R3=Cl, R'1=R'2=R'3=Cl; M=Ti, X=X'=O, L=L'=Cl, R1=i-Bu, R2=R3=H; R'1=i-Bu, R'2=R'3=H; M=Ti, X=X'=O, L=L'=Cl, R1=R3=i-Bu, R2=H; R'1=R'3=i-Bu, R'2=H; M=Ti, CH3; M=Ti, X=X'=NH, L=L'=Cl, R1=R2=R3=H, R'1=R'2=R'3=H; M=Ti, X=X'=NH, L=L'=Cl, R1=R2=R3=CH3, R'1=R'2=R'3=CH3; M=Ti, X=X'=NH, L=L'=Cl, R1=R3=CH3, R2=H, R'1=R'3=CH3, R'2=H; M=Ti, X=X'=NH, L=L'=Cl, R3=CH3, R1=R2=H, R'3=CH3, R'1=R'2=H; M=Ti, X=X'=NH, L=L'=Cl, R1=R2=H, R3=Cl, R'1=R'2=H, R'3=Cl; M=Ti, X=X'=NH, L=L'=Cl, R1=R2=R3=Cl, R'1=R'2=R'3=Cl; M=Ti, X=X'=NH, L=L'=Cl, R1=i-Bu, R2=R3=H; R'1=i-Bu, R'2=R'3=H; M=Ti, X=X'=NH, L=L'=Cl, R1=R3=i-Bu, R2=H; R'1=R'3=i-Bu, R'2=H; M=Ti, CH3; M=Ti, M=Ti, X=X'=O, L=L'=Cl, R1=R2=OCH3, R3=Cl, R'1=R'2=OCH3, R'3=Cl; M=Ti, X=X'=O, L=L'=Cl, R1=R2=R3=OCH3, R'1=R'2=R'3=OCH3; M=Ti, X=X'=O, L=L'=Cl, R1=OBu, R2=R3=H; R'1=OBu, R'2=R'3=H; M=Ti, X=X'=O, L=L'=Cl, R1=R3=OBu, R2=H; R'1=R'3=OBu, R'2=H; M=Ti, CH3; M=Ti, X=X'=NH, L=L'=Cl, R1=R2=R3=OCH3, R'1=R'2=R'3=OCH3; M=Ti, X=X'=NH, L=L'=Cl, R1=R2=R3=OBu, R'1=R'2=R'3=OBu; M=Ti, M=Ti, M=Ti, X=X'=NH, L=L'=Cl, R1=R2=H, R3=OCH3, R'1=R'2=H, R'3=OCH3.

3. The method for preparing polyethylene wax according to claim 1, characterized in that: The non-metallocene catalyst is prepared by the following method: S1, dissolving a biaryl ligand containing nitrogen, oxygen or sulfur heteroatoms in an organic solvent to obtain a component A solution; S2, dissolving a compound containing one of the transition metal atoms from Group IIIB to Group IB in an organic solvent to obtain a component B solution; S3, adding the component B solution dropwise to the component A solution at a temperature of 0°C to 50°C under stirring, and refluxing at a constant temperature of 50°C to 120°C for 1h to 4h; S4, under argon environment, cool the reaction system to 0°C to 30°C, and stir the reaction for 12h to 48h; S5, distilling the liquid in the reaction system under reduced pressure to obtain a viscous solid, washing it with an organic solvent, filtering it, and drying it to obtain a powdered solid catalyst.

4. The method for preparing polyethylene wax according to claim 3, characterized in that: The biaryl ligand containing nitrogen, oxygen or sulfur heteroatoms is substituted or unsubstituted biphenol or diphenylamine, preferably 2,2'-biphenol; the compound containing one of the transition metal atoms from Group IIIB to Group IB is a chloride or bromide of the metal, preferably titanium tetrachloride; the organic solvent is one or more of toluene, dichloromethane, tetrahydrofuran, n-hexane and n-heptane, preferably toluene.

5. The method for preparing polyethylene wax according to claim 3, characterized in that: The molar ratio of the biaryl ligand to the compound containing one of the transition metal atoms from Group IIIB to Group IB is 1:0.8 to 1:1.

2.

6. The method for preparing polyethylene wax according to claim 1, characterized in that: The solvent a is one or more of benzene, toluene, o-xylene, n-hexane, n-heptane and cyclohexane, preferably toluene.

7. The method for preparing polyethylene wax according to claim 1, characterized in that: The cocatalyst b is an alkyl aluminum, and the alkyl aluminum is one or more of triethyl aluminum, diethyl aluminum monochloride, ethyl aluminum dichloride, sesquiethyl aluminum, isobutyl aluminum dichloride, triisobutyl aluminum, diisopropyl aluminum monochloride, methyl n-propyl aluminum monochloride and diphenyl aluminum monochloride, preferably semi-ethyl aluminum chloride, and the cocatalyst b is added in a solution with a mass concentration of 10% to 50%, and the solvent of the solution is selected from one or more of cyclohexane, toluene, and isoparaffin solvent oil, preferably toluene.

8. The method for preparing polyethylene wax according to claim 1, characterized in that: The terminator d is one or more of water, acids, alcohols and organic amines, preferably one or more of hydrochloric acid, ethanol and octanol.

9. The method for preparing polyethylene wax according to claim 1, characterized in that: The polymerization reaction temperature is 50-110° C., preferably 65-100° C., and the reaction time is 5-300 min, preferably 5-180 min.

10. The method for preparing polyethylene wax according to claim 1, characterized in that: The amount of solvent a is 10% to 100% of the volume of the reactor, preferably 20% to 60%, the ethylene introduction pressure is 0.1 to 3 MPa, preferably 1 to 3 MPa, the weight ratio of solvent a to main catalyst c is 10 3 ~10 6 , preferably 10 4 ~10 5 The weight ratio of the solvent a to the co-catalyst b is 5×10 3 ~10 4 , preferably 5×10 3 ~10 3 .

11. The polyethylene wax prepared by the method according to any one of claims 1 to 10, characterized in that: The average molecular weight of the polyethylene wax is 1500-2500 g / mol, and the polymer dispersibility index PDI is 1.5-3.0.

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