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Small-scale synthesis and curing method of a carboxyl-terminated liquid fluoroelastomer

A technology of fluoroelastomer and synthesis method, applied in the field of small-scale synthesis and curing of carboxyl-terminated liquid fluoroelastomer, can solve the problem of high curing temperature and achieve the effect of high reaction efficiency

Active Publication Date: 2018-06-29
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In addition to the traditional curing methods of fluoroelastomers, carboxyl-terminated liquid fluoroelastomers can also be cured with isocyanate and epoxy compounds, but the curing temperature is higher

Method used

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  • Small-scale synthesis and curing method of a carboxyl-terminated liquid fluoroelastomer
  • Small-scale synthesis and curing method of a carboxyl-terminated liquid fluoroelastomer
  • Small-scale synthesis and curing method of a carboxyl-terminated liquid fluoroelastomer

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (a) First add 5L of acetone into a 10L reactor, and add 2000g of vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer (Zhonghao Chenguang FPM2461) into the reactor one by one under mechanical stirring. After the addition, set the temperature at 30° C., rotate at 300 r / min, and stir for 5 hours to completely dissolve the solid fluoroelastomer.

[0025] (b) Set the temperature to 0°C. After the system in the reactor is cooled to 0°C, add 100 g of benzyltriethylammonium chloride and stir for 10 minutes.

[0026] (c) at first preparation 850g mass fraction is the KOH aqueous solution of 45%, takes by weighing 382.5g solid potassium hydroxide, divides and adds in the large beaker that 467.5g deionized water is housed in cold water, constantly stirs, until all Dissolved without exotherm. Then weigh 800g of 30% hydrogen peroxide solution in another large beaker. Use a peristaltic pump to control the rate of addition of alkali and oxidant. First, add a mass f...

Embodiment 2-5

[0030] The specific implementation method is the same as in Example 1, except that the types of raw materials and the reaction temperature are changed. The reaction temperature in Example 2-3 is -10°C, and the reaction temperature in Example 4-5 is 40°C. The specific changes are shown in Table 1, and the results are also listed in Table 1. Carboxyl content was determined by acid-base titration.

[0031]

Embodiment 6

[0033] (a) First add 2.5L of acetone into a 10L reactor, and add 1000g of vinylidene fluoride-perfluoromethyl vinyl ether copolymer (Russian CKΦ260) into the reactor one by one under mechanical stirring. After the addition, set the temperature at 30°C and the rotation speed at 300r / min. After stirring for 4 hours, add 2.5L petroleum ether to make the system in the reactor free of air bubbles. Stir for another hour to completely dissolve the solid fluoroelastomer. Other follow-up steps are with embodiment 1, and charging amount is also with embodiment 1.

[0034] The resulting product was a pale yellow viscous substance at room temperature. The number average molecular weight is 3081, the molecular weight distribution width is 2.34, and the carboxyl content is 2.163%. 1776cm in the infrared spectrum -1 The characteristic absorption peak at -C=O indicates that the carboxyl-terminated liquid fluoroelastomer was successfully synthesized. The dynamic viscosity at 27°C is 75000cp...

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Abstract

The invention discloses a laboratory-scale synthesizing and curing method of a terminal carboxyl liquid fluorine elastomer. The method comprises the following steps: dissolving a fluorine elastomer in an organic solvent; carrying out oxidative degradation reaction in the presence of oxidant and alkali, in which the reaction time lasts for 8-24 hours, and the reaction temperature changes in a range of 10-40 DEG C; and controlling the dripping speed of the oxidant and the alkali via a peristaltic pump to obtain the terminal carboxyl liquid fluorine elastomer. The synthesizing method has the characteristics of few by-products, simplicity and controllability, and high yield. The terminal carboxyl liquid fluorine elastomer can be cured by reacting with carbodiimide-containing compounds under the normal temperature; the cured product has the characteristics of high mechanical performance, high resistance to high temperature and low temperature and high resistance to chemical media; the terminal carboxyl liquid fluorine elastomer can be used for preparing sealants and adhesives with resistance to chemical media and can also be used for preparing terminal-sealed liquid fluorine elastomers such as hydroxyl, silane, epoxy and amino and the like through terminal group transformation reaction.

Description

technical field [0001] The invention relates to a small-scale synthesis and curing method of a carboxyl-terminated liquid fluoroelastomer. Background technique [0002] Liquid fluoroelastomer is a new branch of the fluoroelastomer family. Its molecular weight is lower than that of traditional fluoroelastomers, but it inherits the excellent heat resistance, oxidation resistance and chemical resistance of fluoroelastomers. Moreover, the application range of the fluoroelastomer is broadened. Carboxyl-terminated liquid fluoroelastomers can be cured into any desired shape at a relatively low temperature, and can be widely used in building exterior coatings and oil tank sealants, etc., and are especially suitable for bonding, surface protection and porosity under harsh conditions It is an ideal sealing material, adhesive and coating for the aviation industry. [0003] At present, carboxyl-terminated liquid fluoroelastomers are mainly prepared by adding a suitable molecular weigh...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F214/22C08F8/50C08L27/16C08L79/00C08J5/18
CPCC08F8/50C08J5/18C08J2327/16C08J2479/00C08L27/16C08L2201/08C08L2203/16C08F214/22C08F214/222C08L79/00
Inventor 张孝阿王亚琴武建华杨晓雪江盛玲吕亚非
Owner BEIJING UNIV OF CHEM TECH
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