Polyethylene resin for hollow product, and composition and preparation method thereof

A technology of polyethylene resin and products, applied in the field of polyethylene resin for hollow products and its composition and preparation, can solve the problems such as the reduction of polymer crystallinity and tensile strength, etc.

Active Publication Date: 2021-04-20
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

By introducing different amounts of tether molecules into the linear polymer, it was found that increasing the density of tether molecules to a certain extent would lead to a decrease in the crystallinity and tensile strength of the polymer

Method used

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  • Polyethylene resin for hollow product, and composition and preparation method thereof
  • Polyethylene resin for hollow product, and composition and preparation method thereof
  • Polyethylene resin for hollow product, and composition and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0057] The first step: preparation of chromium-containing catalyst:

[0058] Weigh 40 grams of 955 silica gel in a 1000ml dry beaker and transfer it to a double-cone drum dryer, start the machine to keep the silica gel in a rolling state. Weigh the chromium acetate solution in a 100ml dry beaker (the loading capacity is 0.6% by mass of chromium), add 60ml of deionized water to make an impregnation solution, and spray the impregnation solution into the mixer at a uniform speed to make the silica gel and the chromium acetate solution fully contact ,well mixed. The temperature of the mixer was raised to 80° C., and drying was carried out for 8 hours at a vacuum degree of -0.1 MPa. Move the dried silica gel carrier into a quartz tube, and pass high-purity nitrogen gas into the bottom. The activation time in the nitrogen state is that the activation gas is switched from high-purity nitrogen to dry air when the temperature rises to 300 ° C, and the activation is maintained at 600 °...

Embodiment 2

[0068] The preparation method of the chromium-containing catalyst is the same as in Example 1.

[0069] The difference between the preparation method of polyethylene resin for hollow products and that of Example 1 is that the comonomer gradient (butene / ethylene molar ratio) used during polymerization is 0.04-0.08-0.12, respectively.

[0070] The preparation method of the polyethylene composition for hollow products is the same as that of Example 1.

Embodiment 3

[0072] The preparation method of the chromium-containing catalyst is the same as in Example 1.

[0073] The difference between the preparation method of polyethylene resin for hollow products and Example 1 is that hydrogen is added during polymerization, and the monomer ratio is hydrogen / ethylene molar ratio 0.005:1.

[0074] The preparation method of the polyethylene composition for hollow products is the same as that of Example 1.

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Abstract

The invention relates to the technical field of polyethylene resin, in particular to polyethylene resin for hollow products as well as a composition and a preparation method of the polyethylene resin. The weight-average molecular weight of the polyethylene resin for the hollow product is 180000-320000, the density is 0.950-0.970 g/cm < 3 >, the melt mass flow rate under the load of 21.6 kg is 8-18 g/10 min, the crystallinity is 65-90%, the ESCR is not less than 600 h, and the tensile strength is 24-28 MPa; according to the preparation method, under the action of a chromium-containing catalyst, ethylene is taken as a polymerization monomer, 1-butene is taken as a comonomer, and polymerization is carried out so as to obtain the product. According to the polyethylene resin for the hollow product, the content of short branched chains is increased, the environmental stress cracking resistance is greatly improved, and meanwhile, the density and rigidity of the material are guaranteed; the invention also provides a composition of the composition, which has high environmental stress cracking resistance and maintains high rigidity and toughness. The invention also provides a preparation method thereof.

Description

technical field [0001] The invention relates to the technical field of polyethylene resin, in particular to a polyethylene resin for hollow products, a composition thereof and a preparation method thereof. Background technique [0002] For polyethylene hollow resins, since the final product is applied in the form of a container, environmental stress cracking resistance is an important performance that users pay attention to. Among the methods for evaluating polyethylene environmental stress cracking resistance, the most commonly used method is environmental stress resistance The cracking test (ESCR method) is widely used to evaluate various polyethylene raw materials because of its simple operation and easy sample preparation. [0003] The occurrence of environmental stress cracking belongs to the brittle cracking mechanism. The brittle cracking mechanism is due to the disentanglement between the grain layers. The number and type of tie molecules play an important role in ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F210/16C08F210/08C08F4/69C08F4/02C08L23/08C08K5/134C08K5/526
CPCY02P20/52
Inventor 范大鹏严婕徐晓周建勇李功韬李晓庆鲍春伟朱卫东
Owner CHINA PETROLEUM & CHEM CORP
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