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Chemical degradation method of polypropylene

A technology for chemical degradation of polypropylene, applied in the field of controlled degradation of polypropylene, which can solve the problems of acid sensitivity, large residual groups, and high price, and achieve the effects of improving molecular weight distribution, increasing melt index, and improving degradation efficiency

Active Publication Date: 2008-04-02
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the relative price of this initiator is relatively high, and the residual groups in the system after initiating the degradation of polypropylene are relatively large, which has become a negative factor of concern.
In addition, since it is difficult to completely isolate the whole process from the air during the synthesis and granulation of polypropylene, it is inevitable that some polypropylene molecules will be oxidized into trace acid groups, and the catalyst used in the polymerization process will also generate trace acid groups groups, while organic peroxides without acid groups are sensitive to acids
At the same time, in order to ensure the service life of polypropylene, it is also necessary to add antioxidants containing active hydrogen atoms when granulating polypropylene. These additives will also preferentially consume active free radicals and affect the formation of macromolecular free radicals.
The above factors will affect the effectiveness of the initiator to varying degrees.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0028] (1) Premixing: Take 997.6g homopolypropylene with a melt flow rate of 2g / 10min (produced by Luoyang Petrochemical Polypropylene Co., Ltd., brand F401), 1.0g phosphate nucleating agent CLEARLITENU011, 0.5g antioxidant 1010, 0.5g auxiliary antioxidant 168, 0.4g double 2,5 degradation agent, add the rotation speed in sequence according to the order of homopolypropylene, CLEARLITE NU011, antioxidant 1010, auxiliary antioxidant 168 and double 2,5 degradation agent It is a low-speed mixer at 50-100 rpm, pre-mixed at 20-30°C for 3-5 minutes to form a mixture.

[0029](2) Degradation control: Add the materials mixed in step (1) into the co-rotating parallel twin-screw extruder, control the extrusion temperature of each section to 150-200°C, and the screw speed to 150-250 rpm. The machine speed is 20-50 rpm. See Table 1 for the amount of each substance added in the extrusion process and the properties of the resulting degraded polypropylene product.

example 2

[0031] Carry out premixing and control degradation by the method of example 1, difference is that the consumption of phosphate nucleating agent CLEARLITENU011 is 2g, and the consumption of homopolypropylene is 996.6g. See Table 1 for the amount of each substance added in the extrusion process and the properties of the resulting degraded polypropylene.

example 3

[0033] Carry out premixing and control degradation by the method of example 1, difference is that the consumption of phosphate nucleating agent CLEARLITENU011 is 3g, and the consumption of homopolypropylene is 995.6g. See Table 1 for the amount of each substance added in the extrusion process and the properties of the resulting degraded polypropylene.

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PUM

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Abstract

A chemical degradation method of polypropylene comprises the degradation by adding 0.01 weight percent to 0.2 weight percent of organic peroxide and 0.1 weight percent to 1.0 weight percent of nucleating agent into the polypropylene. The method can effectively improve the efficiency of degradation, increase the melt index of degraded polypropylene, improve the molecular weight distribution of polypropylene, and maintain the good mechanical performances at the same time.

Description

technical field [0001] The invention relates to a controlled degradation method of polypropylene, in particular to a chemical degradation method of polypropylene. Background technique [0002] During the processing of polypropylene, it is often necessary to control the degradation of polypropylene to meet the needs of improving production efficiency and processing technology. U.S. EXXON Chemical Company first realized the controlled degradation of homopolypropylene in 1971. The methods reported in US3,551,943, US3,563,972, US3,608,001, and US3,593,011 mainly adopt the introduction of air during the extrusion process of polypropylene, through The hot air degradation of polypropylene forms free radicals, which triggers β-chain scission of polypropylene to achieve controlled degradation. During the implementation of the above-mentioned patent, the temperature of the barrel of the extruder was as high as 371-427°C, and the temperature distribution mode adopted was reverse distr...

Claims

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Application Information

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IPC IPC(8): C08L23/12C08K5/52B29C47/92B29C47/10C08K5/14B29C48/92
CPCB29C48/92B29C2948/92704B29C2948/9259B29C2948/92828B29C2948/92866B29C2948/92885B29C2948/92895
Inventor 杨军忠刘伟景振华孙春燕周涵代振宇
Owner CHINA PETROLEUM & CHEM CORP
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