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Low compression set peroxide vulcanized fluorine rubber and preparation method thereof

A technology of vulcanizing fluororubber and peroxide, applied in the field of fluororubber synthesis, can solve the problems of inability to use movable or fixed seals, narrow relative molecular weight distribution, large compression set value, etc., and achieve excellent mechanical and dielectric properties, The effect of shortening the vulcanization time and reducing the compression set value

Active Publication Date: 2018-05-11
ZHONGHAO CHENGUANG RES INST OF CHEMICALINDUSTRY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, after peroxide vulcanization, the compression set value is still greater than 19%, and it cannot be used for movable or fixed seals working in petroleum and lubricating oil, fuel oil, hydraulic oil and diester synthetic lubricating oil
[0003] Chinese patent 1989202A discloses a peroxide vulcanizable fluoroelastomer composition, which mainly introduces that the fluidity of the fluoroelastomer composition, which has disadvantages in terms of productivity, is substantially modified to improve processability, but The number-average molecular weight of the obtained fluoroelastomer is only 30,000-70,000, the cross-linking density is not enough, and the vulcanization time is too long, resulting in a relatively large compression set value
Although the number average molecular weight meets the requirements, the chain transfer agent is added in batches to maintain a certain concentration, resulting in a narrow relative molecular weight distribution, poor fluidity, and a large compression set value.

Method used

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  • Low compression set peroxide vulcanized fluorine rubber and preparation method thereof
  • Low compression set peroxide vulcanized fluorine rubber and preparation method thereof

Examples

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Effect test

Embodiment 1

[0057] This embodiment relates to a preparation method of peroxide vulcanized fluororubber with low compression set, comprising the following steps:

[0058] 1) In a 50L stainless steel vertical reaction kettle, add 33.3L of deionized water, blow nitrogen and deoxygenate three times, evacuate until the oxygen content is less than or equal to 25ppm, add 80g of fluorine-containing compound emulsifier microemulsion, 20g of dipotassium hydrogen phosphate, 40g of three Bromofluoroethylene;

[0059] 2) Turn on stirring at a speed of 200rpm, heat up to 60°C, add vinylidene fluoride, tetrafluoroethylene and HFP mixed monomers to 2MPa according to the ratio of the amount of substances 70 / 10 / 20, and after the system is stable, pass 10g through the metering pump Potassium sulfate was added to the reactor to start the polymerization reaction. Simultaneously add mixed monomer constantly to keep reactor pressure 2MPa, after conversion rate reaches 15%, add 40g of 1,4-diiodoperfluorobutane ...

Embodiment 2

[0062] This embodiment relates to a preparation method of peroxide vulcanized fluororubber with low compression set, comprising the following steps:

[0063] 1) In a 50L stainless steel vertical reaction kettle, add 33.3L of deionized water, blow nitrogen and deoxygenate three times, evacuate until the oxygen content is less than or equal to 25ppm, add 80g of fluorine-containing compound emulsifier microemulsion, 20g of dipotassium hydrogen phosphate, 40g of three Bromofluoroethylene;

[0064] 2) Turn on stirring at a speed of 200rpm, heat up to 60°C, add VDF / HFP=55 / 45 (molar ratio) mixed monomer, increase the pressure to 2MPa at 80°C, and press in 10g of 15% (wt) through a metering pump Aqueous ammonium persulfate solution was used to initiate the polymerization reaction, and then a mixed monomer of VDF / HFP=82 / 18 (molar ratio) was added to maintain the reaction pressure at 2.0 MPa. When the conversion rate reaches 20%, add 40g of 1,4-diiodoperfluorobutane to the reactor;

...

Embodiment 3

[0067] This embodiment relates to a preparation method of peroxide vulcanized fluororubber with low compression set, comprising the following steps:

[0068] 1) In a 50L stainless steel vertical reaction kettle, add 33.3L of deionized water, blow nitrogen and deoxygenate three times, evacuate until the oxygen content is less than or equal to 25ppm, add 80g of fluorine-containing compound emulsifier microemulsion, 20g of dipotassium hydrogen phosphate, 40g of three Bromofluoroethylene;

[0069] 2) Start stirring at a speed of 200rpm, heat up to 60°C, add a mixed monomer of TFE / VDF / HFP=4 / 60 / 36 (molar ratio), increase the pressure to 2MPa at 80°C, and press in 10g of 15 % (wt) ammonium persulfate aqueous solution to initiate the polymerization reaction, and then add a mixed monomer of TFE / VDF / HFP=6.3 / 77.2 / 16.5 (molar ratio) to maintain the reaction pressure at 2.0 MPa. When the conversion rate reaches 30%, add 40g of 1,4-diiodoperfluorobutane to the reactor;

[0070] 3) Stop th...

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Abstract

The invention relates to a preparation method of a low compression set peroxide vulcanized fluorine rubber. Specifically, in the preparation process of the peroxide vulcanized fluorine rubber by batchemulsion method, a fluorine-containing compound emulsifier is selected as the emulsifier, and the fluorine-containing compound emulsifier microemulsion is a mixture of a carboxyl-containing perfluoropolyether surfactant and a nonionic fluorocarbon surfactant in a mass ratio of 1:0.4-0.7. Further, by selecting a bromine-containing vulcanization point monomer and an iodine-containing chain transferagent and controlling the adding time of the chain transfer agent, the compression set value of fluorine rubber can be further reduced, the tensile strength is strengthened, and excellent mechanicaland dielectric properties, heat resistance and the like of the fluorine rubber can be ensured.

Description

technical field [0001] The invention relates to the field of fluororubber synthesis, in particular to a fluororubber with low compression set and a preparation method thereof. Background technique [0002] Fluorine rubber has excellent heat resistance, good chemical and physical mechanical properties, electrical insulation properties and radiation resistance, and has become an indispensable and irreplaceable basic material in modern industry, especially in high-tech fields. As we all know, as a rubber seal, low compression set is one of the main properties to ensure its sealing ability. As an elastomer with high temperature resistance and excellent medium resistance, fluororubber is mainly used as movable and fixed seals, which requires it to have a low compression set value. Since the advent of fluororubber raw rubber in the 1950s, the research on its matching technology has focused on reducing the compression permanent deformation of the rubber for a long time, including ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F214/22C08F214/26C08F214/28C08F214/18C08F2/26C08F2/30C08F2/38C08L27/16C08K5/14
CPCC08F2/26C08F2/30C08F2/38C08F214/22C08K5/14C08L2201/08C08F214/26C08F214/28C08F214/18C08L27/16
Inventor 王先荣汪仲权曾波张廷健余金龙龚蓉
Owner ZHONGHAO CHENGUANG RES INST OF CHEMICALINDUSTRY CO LTD