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Tetrafluoroethylene-hexafluoropropylene resin for mold pressing and preparation method thereof

A technology of polyperfluoroethylene propylene and resin, which is applied in the field of polyperfluoroethylene propylene resin for molding and its preparation, can solve the problems of unfavorable industrialization, corrosion, cracks of FEP products, etc., so as to facilitate industrial production, improve application fields, Corrosion reduction effect

Inactive Publication Date: 2018-04-06
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

[0007] The FEP molecular chain segment synthesized by an inorganic initiator contains more unstable end groups, such as carboxyl (-COOH), double bond unsaturated group (-CF=CF2), acid fluoride group (-COF), etc., these groups It is easy to be oxidized to produce acidic substances and volatile substances such as hydrofluoric acid, which makes FEP products have strong acidity, which leads to the corrosion of FEP in molten state to most metal substrates, thus affecting the application of this material
[0008] Existing patent literature reports that in the process of melting and processing tetrafluoroethylene and hexafluoropropylene copolymers, the number of end groups of fluoropolymers can be effectively reduced by introducing oxygen, but this method has a long treatment cycle and is not conducive to industrialization. Not conducive to mass production
[0009] In addition, some patent documents have reported that the unstable terminal group of tetrafluoroethylene and hexafluoropropylene copolymer is fluorinated into CF3 by fluorination method. In the treatment process of these reports, fluorine gas with strong oxidizing property is required, which is harmful to the equipment. The requirements are high, and the equipment is highly corrosive, which is not conducive to environmental friendliness and industrial production
[0010] Also some patent documents have reported that in the polymerization process, using organic peroxide initiators to replace inorganic peroxide initiators, the number of unstable end groups of fluoropolymers obtained is significantly reduced, but the activity of organic initiators is relatively strong, because The difference in the reactivity ratio of the polymerized monomer tetrafluoroethylene and hexafluoropropylene is too large, and it is easy to form tetrafluoroethylene homopolymerization segments in the polymer chain segments, resulting in cracks in FEP products and a decline in product grades

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Prepare polyperfluoroethylene propylene resin for molding according to the following method:

[0037] (1) Using perfluorooctanoate as an emulsifier and persulfate as an initiator, under the conditions of 3MPa and 100°C, polymerize tetrafluoroethylene and hexafluoropropylene in water to obtain a polyperfluoroethylene propylene resin emulsion;

[0038] (2) Adjust the pH value of the polyperfluoroethylene propylene resin emulsion to 8.5, let it stand at 70° C. for 8 hours, add water to dilute to a specific gravity of 1.13, stir and coagulate at a rotating speed of 1400 rpm for 30 minutes, and obtain polyfluoroethylene propylene resin;

[0039] (3) washing the polyperfluoroethylene propylene resin several times with water until the electrical conductivity of the washing water is less than 5 μs / cm to end the washing to obtain 10Kg of polyperfluoroethylene propylene resin powder with a water content of 40%;

[0040] (4) Put the polyperfluoroethylene propylene resin powder int...

Embodiment 2

[0045] Compared with Example 1, the only difference is that the thickness of the flat-bottomed pan is 2 cm; sintering at 355° C. for 20 min.

[0046] The polyperfluoroethylene propylene resin for molding prepared by the above method is translucent and granular, with a melting temperature of about 250-270°C, a melt index of 3g / 10min g / 10min, and a density of 2.15g / cm 3 , The number of black spots ≤ 1%, the tensile strength is 2.45MPa, the elongation is 310%, the volatile matter is 0.09%, and the acidic volatile matter is 0.02%.

Embodiment 3

[0048] Compared with Example 1, the only difference is that the thickness of the flat-bottomed pan is 2.5 cm; sintering at 375° C. for 40 min.

[0049] The polyperfluoroethylene propylene resin for molding prepared by the above method is translucent and granular, with a melting temperature of about 250-270°C, a melt index of 4.2g / 10min, and a density of 2.16g / cm 3 , The number of black spots ≤ 1%, the tensile strength is 26MPa, the elongation is 350%, the volatile matter is 0.06%, and the acidic volatile matter is 0.01%.

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Abstract

The invention relates to a method for preparing a tetrafluoroethylene-hexafluoropropylene resin for mold pressing. The method comprises the following steps: preparing tetrafluoroethylene-hexafluoropropylene resin emulsion by utilizing an inorganic initiator by adopting emulsion polymerization, agglomerating, washing, and sintering, thereby obtaining the product. According to the method provided bythe invention, unstable end groups formed by molecule segments are stabilized in the process of synthesizing the tetrafluoroethylene-hexafluoropropylene resin by adopting the inorganic initiator system, excellent overall performance of the tetrafluoroethylene-hexafluoropropylene resin for mold pressing is ensured, and corrosivity of the product on a metal base material is obviously reduced. Therefore, the application field of the material is improved. The method is simple in operation, short in treatment cycle and favorable for industrialized production.

Description

technical field [0001] The invention relates to the field of polyperfluoroethylene propylene production, in particular to a polyperfluoroethylene propylene resin for molding and a preparation method thereof. Background technique [0002] Polyfluoroethylene propylene FEP (F46) is a copolymer of tetrafluoroethylene and hexafluoropropylene monomers, the abbreviation code is FEP. Polyperfluoroethylene propylene FEP is a straight-chain polymer, and the molecular chain can be regarded as the result of a fluorine atom connected to every four carbon atoms on the main chain of polytetrafluoroethylene (PTFE) being replaced by a CF3 group. Compared with PTFE , The symmetry and regularity of the FEP molecular chain are destroyed, the rigidity of the molecular chain is reduced, the flexibility is increased, the melting point of the material is reduced, the fluidity is increased, and the heat resistance is also reduced. The destruction of the regularity of FEP will affect the crystallini...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F214/26C08F214/28C08F2/24
CPCC08F2/24C08F214/26C08F214/28
Inventor 余金龙汪仲权曾波张廷健王先荣龚蓉
Owner ZHONGHAO CHENGUANG RES INST OF CHEMICALINDUSTRY CO LTD