Low-ash and high-density polyethylene resin and preparation method thereof

A technology of high-density polyethylene and low ash, which is applied in the direction of electrical components, circuits, battery pack components, etc., can solve the adverse effects of battery capacity and battery life, reduce the puncture resistance of microporous diaphragms, and reduce the yield of microporous diaphragms. Advanced problems, to achieve the effect of low ash content, uniform composition and high yield

Active Publication Date: 2016-04-20
SINOPEC YANGZI PETROCHEM +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The reduction in the thickness of the microporous diaphragm and the improvement of safety requirements have higher requirements on the thickness, surface density, and mechanical properties of the microporous diaphragm, such as puncture resistance strength. However, the current domestic diaphragm usually has an ash content of 200-400ppm due to the polyethylene raw material used. , even if the ash content of the powder without any additives is 100-300ppm, the residual amount of metal impurities is high, and the surface of the produced microporous diaphragm is prone to pinholes and crystal points, which not only reduces the puncture resistance of the microporous diaphragm, Higher metal impurities will also adversely affect the capacity and endurance of the battery
In addition, excessive pinholes and crystal points are also an important factor for the low yield of lithium-ion battery microporous separators.

Method used

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  • Low-ash and high-density polyethylene resin and preparation method thereof
  • Low-ash and high-density polyethylene resin and preparation method thereof
  • Low-ash and high-density polyethylene resin and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] According to the preparation method of high-density polyethylene powder for microporous diaphragm of low ash lithium-ion battery provided by the present invention, in 200L hexane solvent, add cocatalyst triethylaluminum 4.5KG / h, loaded Ziegler-Natta successively Catalyst 2.5KG / h, stirred and mixed for about 1 hour under the protection of nitrogen, and fresh ethylene, hydrogen, etc. The average residence time in the kettle is about 1 to 2 hours to obtain the polyethylene component I; after the material is flashed to remove volatile components, it enters the second reaction kettle; no new catalyst is added to the second reaction kettle, and continuous Feed ethylene, hydrogen, and comonomer butene-1, and the average residence time of the materials is about 1 to 2 hours to obtain polyethylene component II and an ethylene polymer mixture containing polyethylene component I produced in the first kettle; After flash evaporation to remove volatile components, it enters the thir...

Embodiment 2

[0052] Basically the same as Example 1, but with the following changes:

[0053] The ethylene feed rates of the first reactor, the second reactor and the third reactor were changed to 4.0t / h, 4.5t / h and 1.5t / h respectively;

[0054] The α-olefin feed amount of the second reactor and the third reactor is changed to 0;

[0055] The hydrogen / ethylene volume ratios of the first reactor, the second reactor and the third reactor were respectively changed to 0.2-0.5%, 0.10-0.3%, 0.1-0.2%;

[0056] The temperature of the second and third reactors is controlled at 75-83°C and 79-87°C respectively.

[0057] The specific production process control parameters of the reactor are shown in Table 2. The high-density polyethylene powder for wet-process lithium-ion battery microporous separator is recorded as HDPE-2, and the test results are shown in Table 6.

[0058] The production process parameter of table 2 embodiment 2

[0059]

Embodiment 3

[0061] Basically the same as Example 1, but with the following changes:

[0062] The ethylene feed rates of the first, second and third reactors were changed to 5.5t / h, 3.5t / h and 1.0t / h respectively;

[0063] The α-olefin feeding amount of the first reactor and the second reactor is all changed into propylene, and the addition is changed into 5kg / h;

[0064] The temperature control of the first reactor is changed to 65-75°C, and the pressure of the kettle is changed to 0.25-0.5MPa. The temperature of the second reactor is controlled at 70-80°C, and the pressure of the kettle is changed to 0.2-0.35MPa.

[0065] The specific production process control parameters of the reactor are shown in Table 3. The high-density polyethylene powder used for the microporous diaphragm of the low-ash lithium-ion battery is recorded as HDPE-3, and the test results are shown in Table 6.

[0066] The production process parameter of table 3 embodiment 3

[0067]

[0068]

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Abstract

The present invention discloses a low-ash and high-density polyethylene resin and a preparation method thereof, wherein the weight average relative molecular mass of the low-ash and high-density polyethylene resin is 3.0*10<5>-9.0*10<5>, the relative molecular mass distribution is 5-9, the density is 0.940-0.965 g/cm<3>, and the ash content is less than 100 ppm. According to the present invention, the low-ash and high-density polyethylene resin has advantages of uniform composition, low ash, low metal impurity content, and the like; with the three-reaction kettle series connection method, the relative molecular mass, the relative molecular mass distribution and the co-polymerization monomer distribution of the polymerization product are easy to adjust, and the method can be directly used for molding of the wet lithium-ion battery separation membrane; and the molded microporous separation membrane has characteristics of uniform pore size distribution, less pinholes, less fisheye, high yield, high tensile strength, and high puncture strength.

Description

technical field [0001] The invention relates to a low-ash high-density polyethylene resin and a preparation method thereof. Background technique [0002] Lithium-ion battery separator is one of the four key components of lithium-ion batteries (positive electrode, negative electrode, separator, electrolyte). The performance of the separator determines the interface structure and internal resistance of the battery, which directly affects the capacity, cycle and safety performance of the battery. A separator with excellent performance plays an important role in improving the overall performance of the battery. [0003] Polyethylene microporous separator is the most widely used type of separator for lithium-ion batteries, and is usually produced by the so-called wet process. That is to mix liquid hydrocarbons or some small molecular substances with polyolefin resin, heat and melt to form a uniform mixture, then cool down to separate phases, press to obtain a membrane, and then ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F210/02C08F210/16C08F110/02C08F4/642C08F2/01C08F2/00H01M2/16H01M50/403H01M50/417H01M50/491H01M50/494
CPCY02P20/52
Inventor 左胜武邱敦瑞徐振明傅勇袁小亮
Owner SINOPEC YANGZI PETROCHEM
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