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Grading method of nitrile rubber

A technology of nitrile rubber and grading method, which is applied in the grading field of nitrile rubber, and can solve the problems of nitrile rubber process performance deterioration, limited application, difficulty in meeting actual needs, etc.

Pending Publication Date: 2020-09-18
内蒙合成化工研究所
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The Mooney viscosity of commercially available nitrile rubber (at 100°C, ML 1+4) is in the range of 30 to 70, the molecular weight is generally above hundreds of thousands, and the molecular weight distribution is generally above 3.5. High molecular weight, high Mooney viscosity, wide Molecular weight deteriorates the process performance of nitrile rubber, which limits its application in special fields. Therefore, it is necessary to design a method that can prepare a series of nitrile rubbers with molecular weights from high to low with a narrow molecular weight distribution according to application requirements. sample
[0003] At present, the method commonly used to improve the processing performance of nitrile rubber is thermomechanical treatment, but this treatment method can only reduce the molecular weight of nitrile rubber to a certain extent. After treatment, the molecular weight is still very high and the molecular weight distribution is still very wide. Unsaturated double bonds are easily oxidized during the treatment process, which affects the later aging performance and is difficult to meet actual needs

Method used

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  • Grading method of nitrile rubber
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  • Grading method of nitrile rubber

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Example 1: In a 10 L three-necked flask, add 160 g of CHK-33 nitrile rubber and 5174 g of acetone, heat, stir and reflux to dissolve completely, keep the temperature at 25°C, slowly add deionized water dropwise under stirring conditions, drop When adding 10 g to 50 g, a precipitate forms, which disappears instantly under stirring conditions; when the dripping water volume is 100 g, a precipitate begins to precipitate, add 20 g of deionized water to make it reach the equilibrium of the precipitate and dissolve, and let it stand for 24 hours; After placing, observe that the precipitate does not disappear, stir to make it turbid, pour it into a centrifuge bottle and centrifuge at a speed of 3000 rpm, and centrifuge for 5 minutes. After drying in an oven, the molecular weight and molecular weight distribution were analyzed by laser light scattering and diffraction.

[0025] The supernatant liquid repeats the above steps 3 times, and the addition amount of precipitating agen...

Embodiment 2

[0029] Example 2: In a 10 L three-necked flask, add 160 g of JSR220 nitrile rubber and 3040 g of acetone, stir to dissolve completely, keep the temperature at 20°C, slowly add deionized water dropwise under stirring conditions, and drop 10 g to 60 At 1 g, the precipitate formed, and then disappeared instantly under stirring conditions; when the dripping water volume was 150 g, the precipitate began to precipitate, and 20 g of deionized water was added to make it reach the equilibrium of the precipitate and dissolve, and stood for 24 hours; after standing, observe the precipitate If it does not disappear, stir to make it turbid, pour it into a centrifuge bottle and centrifuge at a speed of 4500 rpm for 5 min to separate the lower jelly, number 2-1, and dry it in a vacuum oven. The molecular weight and molecular weight distribution were analyzed by laser light scattering diffraction method.

[0030] Repeat the above steps 4 times for the supernatant, and the addition amount of p...

Embodiment 3

[0034] Example 3: In a 10 L three-necked flask, add 160 g of N21 nitrile rubber and 3040 g of methyl ethyl ketone, stir and reflux to dissolve it completely, keep the temperature at 35°C, slowly add deionized water dropwise under stirring conditions, and drop 10g~ At 50 g, the precipitate formed, and then disappeared instantly under stirring conditions; when the dripping water volume was 160 g, the precipitate began to precipitate, and 10 g of deionized water was added to make it reach the equilibrium of the precipitate and dissolve, and stood for 30 h; after standing, observe If the precipitate does not disappear, stir to make it cloudy, pour it into a centrifuge bottle and centrifuge at a speed of 5500 rpm for 5 min, separate the lower layer of jelly, number 3-1, and dry in a vacuum oven , the molecular weight and molecular weight distribution were analyzed by laser light scattering and diffraction.

[0035] Repeat the above steps 4 times for the supernatant, and the additio...

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Abstract

The invention relates to the field of nitrile rubber preparation, and especially relates to a grading method of nitrile rubber. Nitrile rubber samples with narrow molecular weight distribution can beprepared. The method comprises the following operation steps: S1, mixing nitrile rubber and a good solvent according to a certain ratio, and stirring for dissolving to form a solution; S2, stirring ata certain temperature, adding a precipitant into the solution obtained in step S1, and standing to achieve precipitation dissolution equilibrium; S3, separating asupernatant from a lower precipitate;and S4, repeating steps S2 and S3 to obtain the nitrile rubber with the molecular weight distribution less than 2. By selecting the good solvent and the precipitant of the nitrile rubber, the concentrated phase and dilute phase of the nitrile rubber are repeatedly separated, thereby preparing a series of nitrile rubber samples with narrow molecular weight distribution from high molecular weight to low molecular weight.

Description

technical field [0001] The invention relates to the field of nitrile rubber preparation, in particular to a grading method for nitrile rubber. Background technique [0002] Acrylonitrile-butadiene rubber (NBR) is prepared by the polymerization of butadiene and acrylonitrile. It has excellent high temperature resistance, aging resistance, chemical corrosion resistance and excellent adhesion performance, and has been widely used in oil drilling. , petrochemical industry, automobile industry, aerospace, light textile industry, building materials and other fields. The Mooney viscosity of commercially available nitrile rubber (at 100°C, ML 1+4) is in the range of 30 to 70, the molecular weight is generally above hundreds of thousands, and the molecular weight distribution is generally above 3.5. High molecular weight, high Mooney viscosity, wide Molecular weight deteriorates the process performance of nitrile rubber, which limits its application in special fields. Therefore, it ...

Claims

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Application Information

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IPC IPC(8): C08C2/02
CPCC08C2/02
Inventor 暴利军林宏吴勇郝平刘善友于凤林朱麟鹏
Owner 内蒙合成化工研究所