阅读说明：本技术 一种窄分布聚乙烯蜡及其制备方法 (Narrow-distribution polyethylene wax and preparation method thereof ) 是由 刘振宇 李禄建 陈锦丰 王伟哲 刘国禹 陈雄华 宋莎 谢京燕 于 2019-10-30 设计创作，主要内容包括：本发明公开了一种窄分布聚乙烯蜡及其制备方法,该制备方法包括：在反应釜中,加入乙烯、催化剂、助催化剂和有机溶剂,催化反应,然后加入催化剂终止剂终止反应,将得到的产物过滤,洗涤,烘干得到窄分布聚乙烯蜡。本发明的窄分布聚乙烯蜡分子量在500～2000,分子量分布窄,PDI可以到1.4～3.0,具有良好的润滑性、加工性和金属颜料定位性；本发明提供的窄分布聚乙烯蜡的制备方法简单易行、稳定,且成本低,适合工业化生产。(The invention discloses narrow-distribution polyethylene wax and a preparation method thereof, wherein the preparation method comprises the following steps: and adding ethylene, a catalyst, a cocatalyst and an organic solvent into a reaction kettle, carrying out catalytic reaction, adding a catalyst terminator to terminate the reaction, filtering, washing and drying the obtained product to obtain the narrow-distribution polyethylene wax. The narrow-distribution polyethylene wax has the molecular weight of 500-2000, has narrow molecular weight distribution, has PDI of 1.4-3.0, and has good lubricating property, processability and metallic pigment positioning property; the preparation method of the narrow-distribution polyethylene wax provided by the invention is simple, feasible, stable and low in cost, and is suitable for industrial production.)

1. The narrow-distribution polyethylene wax is characterized by being prepared by an ethylene in-situ polymerization method, the weight average molecular weight is 500-2000, and the PDI of the narrow-distribution polyethylene wax is 1.4-3.0.

2. A preparation method of narrow-distribution polyethylene wax is characterized by comprising the following steps: adding an organic solvent, ethylene, a catalyst and a cocatalyst into a reaction kettle, carrying out catalytic reaction, then adding a catalyst terminator to terminate the reaction, filtering, washing and drying the obtained product to obtain the narrow-distribution polyethylene wax.

3. The process according to claim 2, wherein the reaction is carried out under anhydrous and oxygen-free conditions, and the reaction vessel is replaced with ethylene gas before the reactants are added.

4. The preparation method according to claim 2 or 3, wherein in the catalytic reaction, the amount of the organic solvent is 10% to 100% of the volume of the reaction kettle, the feeding pressure of the ethylene is 0.1 to 10MPa, the amount of the catalyst is 0.000001 to 0.001 of the weight of the organic solvent, and the amount of the cocatalyst is 0.0001 to 0.005 of the weight of the organic solvent; the reaction temperature of the catalytic reaction is 10-200 ℃; the reaction time of the catalytic reaction is 5-240 min; preferably, in the catalytic reaction, the dosage of the solvent is 40-80% of the volume of the reaction kettle, the introducing pressure of the ethylene is 2-6 MPa, the dosage of the catalyst is 0.00001-0.0001 of the weight of the organic solvent, and the dosage of the cocatalyst is 0.001-0.005 of the weight of the organic solvent; the reaction temperature of the catalytic reaction is 40-100 ℃; the reaction time of the catalytic reaction is 10-60 min.

5. The production method according to any one of claims 2 to 4, wherein the organic solvent is an organic solvent subjected to anhydrous treatment.

6. The method according to any one of claims 2 to 5, wherein the organic solvent is one or more of benzene, toluene, o-xylene, n-hexane, n-heptane and cyclohexane.

7. The production method according to any one of claims 2 to 6, wherein the catalyst is Ph₂PN[CH(CH₃Ph)]PPh₂·CrCl₃And Ph₂PN(CHPh₂)PPh₂·CrCl₃One or two of them.

8. The method of any one of claims 2-7, wherein the cocatalyst is one or more of methylaluminoxane, modified methylaluminoxane, triethylaluminum and triisobutylaluminum.

9. The production method according to any one of claims 2 to 8, wherein the catalyst terminator is one or more of water, an organic acid, an inorganic acid, an alcohol, and an organic amine compound; preferably, the catalyst terminator is one or more of hydrochloric acid, ethanol and octanol.

10. The method according to any one of claims 2 to 9, wherein the cocatalyst is added in a solution having a mass concentration of 10% to 50%, and the solvent of the solution is one or more selected from cyclohexane, toluene, and isoparaffin solvent oil.

Technical Field

The invention relates to a functional polymer material, in particular to narrow-distribution polyethylene wax and a preparation method of the polyethylene wax.

Background

Polyethylene wax (PE wax), also called polymer wax for short polyethylene wax. It is widely used because of its excellent cold resistance, heat resistance, chemical resistance and wear resistance. At present, the production capacity of polyethylene wax in China is far from meeting the market demand, most of polyethylene wax is imported from foreign countries, and the price is expensive. In normal production, this wax can be added directly to the polyolefin process as an additive, which can increase the gloss and processability of the product. As a lubricant, the lubricant has stable chemical properties and good electrical properties. The polyethylene wax has good compatibility with polyethylene, polypropylene, polyethylene cerotic acid, ethylene propylene rubber and butyl rubber, and can improve the fluidity of polyethylene, polypropylene and ABS and the mold release property of polymethyl methacrylate and polycarbonate. Polyethylene wax has a stronger internal lubricating effect than PVC and other external lubricants.

The polyethylene wax can be classified into a polymerization type polyethylene wax and a cracking type polyethylene wax according to different preparation methods. The polymerized polyethylene wax is the product produced during the polymerization of ethylene, and the cracking polyethylene wax is produced through heating and cracking polyethylene resin. At present, the polyethylene wax produced in China is prepared by cracking pure high molecular weight polyethylene resin, wherein the cracked polyethylene wax adopts high molecular weight polyethylene as a main raw material, is added with other auxiliary materials, and is prepared by a series of depolymerization reactions. The depolymerization reaction is the most critical ring in the production of the polyethylene wax, and the whole process of the depolymerization reaction is carried out in a closed reaction kettle, so the cost is high.

At present, the molecular weight distribution of the two types of polymeric and cracking polyethylene wax is wider, and the molecular structures of the two types of polyethylene wax have certain differences, so the two types of polyethylene wax are different in application occasions. The molecular weight distribution has an effect on the mechanical properties of the polyethylene wax, while the molecular structure has an effect on the crystallization properties of the polyethylene wax.

Therefore, there is a need in the art for a narrow distribution polyethylene wax and a stable process for its preparation.

Disclosure of Invention

The invention aims to solve the technical problem of providing narrow-distribution polyethylene wax and a preparation method thereof aiming at the defects of the prior art. The narrow-distribution polyethylene wax has narrow molecular weight distribution, good lubricating property, processability and metal pigment positioning property, and the preparation method has simple steps.

Therefore, the narrow-distribution polyethylene wax is obtained by an in-situ polymerization method of ethylene, the average molecular weight of the narrow-distribution polyethylene wax is 500-2000, and the PDI of the narrow-distribution polyethylene wax is 1.4-3.0.

The second aspect of the invention provides a preparation method of narrow-distribution polyethylene wax, wherein the preparation method comprises the following steps: and adding ethylene, a catalyst, a cocatalyst and an organic solvent into a reaction kettle, carrying out catalytic reaction, then adding a catalyst terminator to terminate the reaction, filtering, washing and drying the obtained product to obtain the narrow-distribution polyethylene wax.

In the present invention, it is preferable that the reaction in the preparation method is carried out under anhydrous and oxygen-free conditions, and the reaction vessel is replaced with ethylene gas before the reactants are added.

In the invention, in order to improve the yield and efficiency of the reaction, preferably, in the catalytic reaction, the dosage of the organic solvent is 10-100% of the volume of the reaction kettle, the introducing pressure of the ethylene is 0.1-10 MPa, the dosage of the catalyst is 0.000001-0.001 of the weight of the organic solvent, and the dosage of the cocatalyst is 0.0001-0.005 of the weight of the organic solvent; the reaction temperature of the catalytic reaction is 10-200 ℃; the reaction time of the catalytic reaction is 5-240 min; more preferably, in the catalytic reaction, the dosage of the solvent is 40-80% of the volume of the reaction kettle, the introducing pressure of the ethylene is 2-6 MPa, the dosage of the catalyst is 0.00001-0.0001 of the weight of the organic solvent, and the dosage of the cocatalyst is 0.001-0.005 of the weight of the organic solvent; the reaction temperature of the catalytic reaction is 40-100 ℃; the reaction time of the catalytic reaction is 10-60 min.

In the present invention, the organic solvent is an organic solvent subjected to anhydrous treatment. The anhydrous treatment of the organic solvent can be performed by referring to the method of anhydrous treatment of organic solvent commonly used in the art, for example, the organic solvent is used by refluxing under argon atmosphere the sodium silk-benzophenone until discoloration.

In the present invention, preferably, the organic solvent is one or more of benzene, toluene, o-xylene, n-hexane, n-heptane and cyclohexane. In the present invention, the organic solvent is more preferably toluene.

In the present invention, preferably, the catalyst is Ph₂PN[CH(CH₃Ph)]PPh₂·CrCl₃And Ph₂PN(CHPh₂)PPh₂·CrCl₃One or two of them.

In the present invention, preferably, the cocatalyst is one or more of methylaluminoxane, modified methylaluminoxane, triethylaluminum and triisobutylaluminum, the cocatalyst is added in a solution with a mass concentration of 10-50%, and a solvent of the solution is one or more selected from cyclohexane, toluene and isoparaffin solvent oil. In the present invention, it is preferable that the catalyst terminator is one or more of water, an organic acid, an inorganic acid, an alcohol and an organic amine compound. Further preferably, in the present invention, the catalyst terminator is one or more of hydrochloric acid, ethanol and octanol.

In the present invention, the reaction vessel may be a reaction vessel conventionally used in the art, for example, a reaction vessel with a stirring device and controllable temperature and pressure. All manipulations in the present invention can be carried out using standard Schlenk techniques.

In the present invention, PDI (Polymer dispersion index) is a polymer dispersibility index, which is used to describe a polymer molecular weight distribution, and a ratio of a weight average molecular weight to a number average molecular weight is referred to as a polymer dispersibility index.

Compared with the prior art, the invention has the beneficial effects that:

(1) the narrow-distribution polyethylene wax has the molecular weight of 500-2000, has narrow molecular weight distribution, has PDI of about 1.4, and has good lubricating property, processability and metallic pigment positioning property.

(2) The preparation method of the narrow-distribution polyethylene wax provided by the invention is simple, feasible, stable and low in cost, and is suitable for industrial production.

Drawings

The invention will be described below with reference to the accompanying drawings.

FIGS. 1 to 7 are graphs of molecular weight (GPC) distributions of polyethylene waxes A1-A4 and D1-D3 obtained in examples 1 to 4 of the present invention and comparative examples 1 to 3, respectively, with the X-axis representing the molecular weight distribution, the left Y-axis representing a weight differential curve of the molecular weight, and the right Y-axis representing a weight integral curve.

Detailed Description

In order that the invention may be more readily understood, the invention will now be described in further detail with reference to the accompanying drawings and examples, which are given by way of illustration only and are not limiting to the scope of the invention. The starting materials or components used in the present invention may be commercially or conventionally prepared unless otherwise specified.

The molecular weight distribution in the present invention is determined using the polyethylene molecular weight test method commonly used in high temperature gel chromatography instruments.

Example 1

Preparation of narrow-distribution polyethylene wax

In a 300mL reaction vessel, the reaction vessel with magnetic stirring and temperature control was replaced with ethylene gas 3 times, 80mL of toluene was added as a solvent to the reaction vessel, and 0.0005g of Ph as a catalyst was added₂PN[CH(CH₃Ph)]PPh₂·CrCl₃And 2.5g of cocatalyst of 10 percent methylaluminoxane in toluene, introducing ethylene gas, controlling the pressure of ethylene to be 4MPa, stirring and reacting at 50 ℃ for 0.5h, then releasing ethylene to normal pressure, terminating the reaction by using a 10 percent hydrochloric acid ethanol solution, transferring the polymer into a beaker, standing overnight, filtering, washing a filter cake to be neutral by using absolute ethyl alcohol, and drying at 50 ℃ to constant weight to obtain narrow-distribution polyethylene wax A1.

Example 2

Preparation of narrow-distribution polyethylene wax

In a 300mL reaction vessel, the reaction vessel with magnetic stirring and temperature control was replaced with ethylene gas 3 times, 200mL of toluene as a solvent was added to the reaction vessel, and 0.0002g of Ph as a catalyst was added₂PN[CH(CH₃Ph)]PPh₂·CrCl₃And 1.5g of cocatalyst of 10 percent methylaluminoxane in toluene, introducing ethylene gas, controlling the pressure of ethylene to be 4MPa, stirring and reacting at 50 ℃ for 0.5h, then releasing ethylene to normal pressure, terminating the reaction by using a 10 percent hydrochloric acid ethanol solution, transferring the polymer into a beaker, standing overnight, filtering, washing a filter cake to be neutral by using absolute ethyl alcohol, and drying at 50 ℃ to constant weight to obtain narrow-distribution polyethylene wax A2.

Example 3

Preparation of narrow-distribution polyethylene wax

In a 300mL reaction vessel, the reaction vessel with magnetic stirring and temperature control was replaced with ethylene gas 3 times, 100mL of toluene as a solvent was added to the reaction vessel, and 0.001g of Ph as a catalyst was added₂PN[CH(CH₃Ph)]PPh₂·CrCl₃And 3g of cocatalyst, 10% of methyl aluminoxane in toluene, introducing ethylene gas, controlling the ethylene pressure to be 3MPa, stirring and reacting at 80 ℃ for 0.5h, then releasing ethylene to normal pressure, terminating the reaction by using a 10% hydrochloric acid ethanol solution, transferring the polymer into a beaker, standing overnight, filtering, washing a filter cake to be neutral by using absolute ethyl alcohol, and drying at 50 ℃ to constant weight to obtain narrow-distribution polyethylene wax A3.

Example 4

Preparation of a narrow-distribution polyethylene wax as in example 1, except that the catalyst addition was 0.0005g Ph₂PN(CHPh₂)PPh₂·CrCl₃To obtain polyethylene wax A4.

Example 5

The narrow distribution polyethylene wax was prepared as in example 1, except that 0.0069g of catalyst was added to obtain polyethylene wax A5.

Example 6

A narrow distribution polyethylene wax was prepared as in example 1, except that 0.69g of 10% methylaluminoxane solution in toluene was added as cocatalyst to afford polyethylene wax A6.

Example 7

A narrow distribution polyethylene wax was prepared as in example 1, except that 3.45g of 10% methylaluminoxane solution in toluene was added as cocatalyst to afford polyethylene wax A7.

Example 8

The narrow distribution polyethylene wax was prepared as in example 1, except that the reaction temperature for the catalyzed reaction was 40 ℃ to give polyethylene wax A8.

Example 9

The narrow distribution polyethylene wax was prepared as in example 1, except that the reaction temperature for the catalyzed reaction was 100 ℃ to give polyethylene wax A9.

Comparative example 1

Preparation of a narrow-distribution polyethylene wax as in example 1, except that 0.1g Ph of catalyst was added₂PN(CHPh₂)PPh₂·CrCl₃To obtain polyethylene wax D1.

Comparative example 2

The narrow distribution polyethylene wax was prepared as in example 1, except that the reaction temperature was increased to 120 ℃ to give polyethylene wax D3.

Comparative example 3

The narrow distribution polyethylene wax was prepared as in example 1, except that the ethylene pressure was 7MPa, giving sample D3.

Test example

The polyethylene waxes A1-A9 and D1-D3 prepared in examples 1-9 and comparative examples 1-3 were subjected to determination of molecular weight distribution by a high temperature gel gas chromatography method. Specific results are shown in Table 1

TABLE 1

	Mn	Mw	PDI
				A1	450	665	1.47
A2	631	884	1.40
				A3	435	1143	2.6
A4	422	1213	2.87
				A5	476	714	1.5
A6	481	1255	2.61
				A7	468	692	1.48
A8	455	865	1.9
				A9	530	859	1.62
D1	415	1505	3.63
				D2	24180	178306	7.37
D3	25217	223512	8.86

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.