Preparation method of high-efficiency fusible polytetrafluoroethylene (PFA)

Abstract

The invention discloses a preparation method of high-efficiency fusible polytetrafluoroethylene (PFA), and relates to the technical field of fluorine-containing polymers. The preparation method comprises the following specific steps: adding high-purity water into a polymerization kettle, starting stirring, adding a surfactant, a dispersing aid, a chain transfer agent and a perfluoroalkyl vinyl ether monomer, controlling the temperature and pressure of the polymerization kettle, adding an initiator solution into the reaction kettle, and initiating a copolymerization reaction; the preparation method comprises the following steps: continuously adding a gas mixture of tetrafluoroethylene and perfluoroalkyl vinyl ether into a polymerization kettle after a polymerization reaction is started, continuously adding an initiator solution into a reaction kettle at a constant speed at the same time, and recovering unreacted monomers in the polymerization kettle after the reaction is finished to obtain a fusible polytetrafluoroethylene (PFA) resin emulsion. The method overcomes the problem of low polymerization efficiency caused by low filling coefficient and long solvent recovery period of the original solvent phase PFA polymerization reaction, and improves the utilization rate of raw materials.

Description

Technical Field

[0001] The invention relates to the technical field of fluorine-containing polymers, in particular to a method for preparing high-efficiency fusible polytetrafluoroethylene (PFA). Background Art

[0002] Fusible polytetrafluoroethylene (PFA for short) is a copolymer of tetrafluoroethylene (TFE) and a small amount of perfluoroalkyl vinyl ether (PAVE). Its main chain structure gives it very similar properties to polytetrafluoroethylene, with excellent chemical stability, physical and mechanical properties, electrical insulation, lubricity, non-stickiness, aging resistance, non-flammability and thermal stability. The main chain contains perfluoroalkoxy side groups, which significantly improves the flexibility of the polymer chain, reduces the crystallinity of the polymer, improves the melt viscosity of the polymer, and makes PFA have good thermoplasticity.

[0003] CN113501904A discloses a method for preparing a perfluoroalkyl vinyl ether copolymer, wherein 10 to 28 parts of tetrafluoroethylene monomer, 2 to 5 parts of perfluoroalkyl vinyl ether, 0.01 to 0.1 parts of alkenyl ionic liquid, 0.01 to 0.1 parts of vinyl ferrocene, and 0.2 to 1.2 parts of initiator are added to 100 to 200 parts of solvent by weight for polymerization reaction, the reaction temperature is 20 to 50°C, the reaction pressure is 120 to 500 kPa, and the solvent is recovered after the reaction to obtain a perfluoroalkyl vinyl ether copolymer. However, the method has the following technical problems: 1. The reaction speed is slow and the filling coefficient of the reactor is low; 2. The solvent recovery cycle is long after the reaction is completed. Further optimization design is needed.

[0004] The existing fusible polytetrafluoroethylene (PFA) polymerization process usually uses organic solvents as the medium and acyl fluoride substances as the initiator to carry out the free radical copolymerization of tetrafluoroethylene (TFE) and perfluoroalkyl vinyl ether (PAVE) by solvent phase polymerization. This process is currently widely used, but the PFA product obtained by the usual polymerization process needs to be solvent recovered, and the recovery cycle is about 20 hours, which makes the operation efficiency of a single reactor very low.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The invention provides a method for preparing high-efficiency fusible polytetrafluoroethylene (PFA). By optimizing the process, the problems of low filling coefficient of the original solvent phase PFA polymerization reaction and low polymerization efficiency caused by long solvent recovery cycle are overcome.

[0007] In order to achieve the above-mentioned invention object, this method proposes the following solution:

[0008] A method for preparing high-efficiency fusible polytetrafluoroethylene (PFA), the operating steps of which are:

[0009] S1: Add 2000-3000 parts of high-purity water to the polymerization kettle according to weight parts, start stirring, control the speed to 10-120rpm, add 10-50 parts of surfactant, 2-5 parts of dispersing aid, 0.01-10 parts of chain transfer agent, 5-40 parts of perfluoroalkyl vinyl ether monomer, adjust the temperature of the polymerization kettle to 60-120°C, add 100-200 parts of tetrafluoroethylene monomer, make the pressure in the reactor reach 1.5-5.0MPa, add 1-10 parts of initiator solution to the reactor to initiate copolymerization reaction;

[0010] S2: After the polymerization reaction starts, a gas mixture of tetrafluoroethylene and perfluoroalkyl vinyl ether is continuously added into the polymerization kettle, and the pressure of the reactor is maintained at 1.5-5.0 MPa. At the same time, the initiator solution is continuously added into the reactor at a constant rate, and the reaction temperature is controlled at 60-120°C. When the amount of mixed monomers added reaches 600-1200 parts, the addition of monomers and initiators is stopped to terminate the copolymerization reaction. After the unreacted monomers in the polymerization kettle are recovered, a fusible polytetrafluoroethylene (PFA) resin emulsion is obtained, and the emulsion is translucent milky white.

[0011] Furthermore, the surfactant is a mixture of one or more of ammonium perfluorooctanoate, ammonium perfluorooctane sulfonate, perfluorooctane sulfonamide, ammonium perfluorohexanoate, and perfluoro-2,5-dimethyl-3,6-dioxanononanoate.

[0012] Furthermore, the surfactant is an aqueous solution with a concentration of 10-30%.

[0013] Furthermore, the chain transfer agent is a straight-linked alkane; the straight-linked alkane molecular formula C n H 2n+2 , where n=1~4.

[0014] Furthermore, the perfluoroalkyl vinyl ether is a mixture of one or more of perfluoromethyl vinyl ether, perfluoroethyl vinyl ether and perfluoro-n-propyl vinyl ether.

[0015] Furthermore, the initiator is an aqueous solution or a mixed solution of potassium persulfate or ammonium persulfate.

[0016] Furthermore, the concentration of the initiator solution is 0.1-5%.

[0017] Furthermore, the initiator is added at a rate of 3 to 10 parts / h.

[0018] Furthermore, the ratio of tetrafluoroethylene to perfluoroalkyl vinyl ether in the mixed monomer is 8-25.

[0019] Furthermore, the preparation method of the dispersing aid is

[0020] H1: Add 10-17 parts of 6-mercaptobenzo[C][1,2]oxaborocyclo-1(3H)-ol (CAS: 2130753-08-9), 2-5 parts of 10,13-epoxy-10,12-octadecadienoic acid, 500-600 parts of DMF, 10-15 parts of triethylamine, and react at 40-50°C for 100-150 minutes.

[0021] H2: Add 50-70 parts of perfluoropolyether (meth)acrylate and 2-5 parts of triethylamine, react at 70-80° C. for 120-180 minutes, and then remove DMF by reduced pressure distillation to obtain a dispersing aid.

[0022] Furthermore, the perfluoropolyether (meth)acrylate has a viscosity of 300 to 1000.

[0023] Reaction mechanism:

[0024] 1. Mercapto-olefin addition reaction and mercapto-epoxy ring-opening reaction:

[0025] In the initial stage, the thiol (-SH) group in 6-mercaptobenzo[C][1,2]oxaborocyclo-1(3H)-ol first undergoes an addition reaction with the olefin moiety in 10,13-epoxy-10,12-octadecadienoic acid. This step forms an intermediate by opening the double bond and combining the thiol group to form a new sulfur-carbon bond.

[0026] Next, the thiol group undergoes a ring-opening reaction with the epoxy group to form a more complex multi-ring structure. This step may involve a nucleophilic attack of the thiol group on the epoxy group, resulting in the ring opening of the epoxy group and the formation of a new chemical bond with the thiol group.

[0027] 2. Continued thiol-olefin addition reaction:

[0028] Based on the previous step, the remaining mercapto groups continue to undergo mercapto-olefin addition reaction with perfluoropolyether (meth)acrylate. This step is also completed by opening the double bond in perfluoropolyether (meth)acrylate and forming a new sulfur-carbon bond with the mercapto group.

[0029] Technical effects:

[0030] Compared with traditional methods, this method has the following advantages:

[0031] 1. Improve polymerization efficiency and filling factor:

[0032] The use of this new dispersant can significantly improve the polymerization reaction. Since the dispersant can more effectively disperse and stabilize the reaction mixture, it can increase the filling factor, that is, the proportion of monomer in the polymerization system, thereby shortening the polymerization reaction time and improving production efficiency. It solves the problem of demulsified powder produced during PFA emulsion polymerization, reduces product waste, and improves the utilization rate of raw materials.

[0033] 2. Simplify solvent recovery and reduce environmental impact:

[0034] The use of the new dispersant also helps to simplify the solvent recovery process after polymerization. This is because the dispersant can reduce the generation of unstable components in the reaction system, reduce side reactions and pollutants, and use water as a solvent and dispersant to further reduce the impact on the environment, making the production process more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is the DSC graph of PFA prepared in Example 4.

[0036] Figure 2 This is the Fourier infrared spectrum of PFA prepared in Example 4.

[0037] Figure 3 This is the nuclear magnetic resonance spectrum of PFA prepared in Example 4. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0039] Example 1

[0040] A method for preparing high-efficiency fusible polytetrafluoroethylene (PFA), the operating steps of which are:

[0041] S1: Add 2000 g of high-purity water to the polymerization kettle, start stirring, control the speed to 30 rpm, add 10 g of surfactant, 2 g of dispersing aid, 0.01 g of chain transfer agent, 5 g of perfluoroalkyl vinyl ether monomer, adjust the temperature of the polymerization kettle to 60°C, add 100 g of tetrafluoroethylene monomer, make the pressure in the reactor reach 1.5 MPa, add 3 g of initiator solution to the reactor, and initiate copolymerization;

[0042] S2: After the polymerization reaction starts, a gas mixture of tetrafluoroethylene and perfluoroalkyl vinyl ether is continuously added into the polymerization kettle, and the pressure of the reactor is maintained at 1.5 MPa. At the same time, the initiator solution is continuously added into the reactor at a constant rate, and the reaction temperature is controlled at 60°C. When the amount of mixed monomer added reaches 600g, the addition of monomers and initiators is stopped to terminate the copolymerization reaction. After the unreacted monomers in the polymerization kettle are recovered, a fusible polytetrafluoroethylene (PFA) resin emulsion is obtained, and the emulsion is translucent milky white.

[0043] The surfactant is ammonium perfluorooctanoate.

[0044] The surfactant is an aqueous solution with a concentration of 10%.

[0045] The chain transfer agent is methane.

[0046] The perfluoroalkyl vinyl ether is perfluoromethyl vinyl ether.

[0047] The initiator is an aqueous solution of potassium persulfate.

[0048] The concentration of the initiator solution is 1%.

[0049] The initiator addition rate is 3 g / h.

[0050] The ratio of tetrafluoroethylene to perfluoroalkyl vinyl ether in the mixed monomer is 8:1.

[0051] The preparation method of the dispersing aid is

[0052] H1: Add 10g 6-mercaptobenzo[C][1,2]oxaborocyclo-1(3H)-ol (CAS: 2130753-08-9), 2g 10,13-epoxy-10,12-octadecadienoic acid, 500g DMF, 10g triethylamine, and react at 40°C for 100 minutes.

[0053] H2: Add 50 g of perfluoropolyether (meth)acrylate and 2 g of triethylamine, react at 70° C. for 120 minutes, and then remove DMF by reduced pressure distillation to obtain a dispersing aid.

[0054] The perfluoropolyether (meth)acrylate has a viscosity of 300.

[0055] The final emulsion product has a specific gravity of 1.19 g / ml, a solid content of 27.3% w / w, and no demulsified powder on the surface of the emulsion.

[0056] Example 2

[0057] A method for preparing high-efficiency fusible polytetrafluoroethylene (PFA), the operating steps of which are:

[0058] S1: Add 2500 g of high-purity water to the polymerization kettle, start stirring, control the speed to 60 rpm, add 25 g of surfactant, 3 g of dispersing aid, 5 g of chain transfer agent, 15 g of perfluoroalkyl vinyl ether monomer, adjust the temperature of the polymerization kettle to 80°C, add 125 g of tetrafluoroethylene monomer, make the pressure in the reactor reach 2.5 MPa, add 5 g of initiator solution to the reactor, and initiate copolymerization;

[0059] S2: After the polymerization reaction starts, a gas mixture of tetrafluoroethylene and perfluoroalkyl vinyl ether is continuously added into the polymerization kettle, and the pressure of the reactor is maintained at 2.5 MPa. At the same time, the initiator solution is continuously added into the reactor at a constant rate, and the reaction temperature is controlled at 80°C. When the amount of mixed monomer added reaches 800g, the addition of monomers and initiators is stopped to terminate the copolymerization reaction. After the unreacted monomers in the polymerization kettle are recovered, a fusible polytetrafluoroethylene (PFA) resin emulsion is obtained, and the emulsion is translucent milky white.

[0060] The surfactant is ammonium perfluorooctane sulfonate.

[0061] The surfactant is an aqueous solution with a concentration of 20%.

[0062] The chain transfer agent is ethane.

[0063] The perfluoroalkyl vinyl ether is perfluoroethyl vinyl ether.

[0064] The initiator is an aqueous solution of ammonium persulfate.

[0065] The concentration of the initiator solution is 2.5%.

[0066] The initiator addition rate is 5 g / h.

[0067] The ratio of tetrafluoroethylene to perfluoroalkyl vinyl ether in the mixed monomer is 14:1.

[0068] The preparation method of the dispersing aid is

[0069] H1: Add 12.5 g 6-mercaptobenzo[C][1,2]oxaborocyclo-1(3H)-ol (CAS: 2130753-08-9), 3 g 10,13-epoxy-10,12-octadecadienoic acid, 550 g DMF, 11.5 g triethylamine, and react at 45°C for 125 minutes.

[0070] H2: Add 60 g of perfluoropolyether (meth)acrylate and 3 g of triethylamine, react at 75° C. for 140 minutes, and then remove DMF by reduced pressure distillation to obtain a dispersing aid.

[0071] The perfluoropolyether (meth)acrylate has a viscosity of 500.

[0072] The final emulsion product has a specific gravity of 1.20 g / ml, a solid content of 30.4% w / w, and no demulsified powder on the surface of the emulsion.

[0073] Example 3

[0074] A method for preparing high-efficiency fusible polytetrafluoroethylene (PFA), the operating steps of which are:

[0075] S1: Add 2500g of high-purity water to the polymerization kettle, start stirring, control the speed to 100rpm, add 40g of surfactant, 4g of dispersing aid, 8g of chain transfer agent, 30g of perfluoroalkyl vinyl ether monomer, adjust the temperature of the polymerization kettle to 100°C, add 165g of tetrafluoroethylene monomer, make the pressure in the reactor reach 4.0MPa, add 8g of initiator solution to the reactor, and initiate copolymerization;

[0076] S2: After the polymerization reaction starts, a gas mixture of tetrafluoroethylene and perfluoroalkyl vinyl ether is continuously added into the polymerization kettle, and the pressure of the reactor is maintained at 4.0 MPa. At the same time, the initiator solution is continuously added into the reactor at a constant rate, and the reaction temperature is controlled at 100°C. When the amount of mixed monomer added reaches 1000g, the addition of monomers and initiators is stopped to terminate the copolymerization reaction. After the unreacted monomers in the polymerization kettle are recovered, a fusible polytetrafluoroethylene (PFA) resin emulsion is obtained, and the emulsion is translucent milky white.

[0077] The surfactant is perfluorooctane sulfonamide.

[0078] The surfactant is an aqueous solution with a concentration of 20%.

[0079] The chain transfer agent is propane.

[0080] The perfluoroalkyl vinyl ether is perfluoroethyl vinyl ether.

[0081] The initiator is an aqueous solution of potassium persulfate.

[0082] The concentration of the initiator solution is 4%.

[0083] The initiator addition rate is 8 g / h.

[0084] The ratio of tetrafluoroethylene to perfluoroalkyl vinyl ether in the mixed monomer is 20:1.

[0085] The preparation method of the dispersing aid is

[0086] H1: Add 15g 6-mercaptobenzo[C][1,2]oxaborocyclo-1(3H)-ol (CAS: 2130753-08-9), 4g 10,13-epoxy-10,12-octadecadienoic acid, 550g DMF, 14g triethylamine, and react at 45°C for 140 minutes.

[0087] H2: Add 60 g of perfluoropolyether (meth)acrylate and 4 g of triethylamine, react at 75° C. for 160 minutes, and then remove DMF by reduced pressure distillation to obtain a dispersing aid.

[0088] The perfluoropolyether (meth)acrylate has a viscosity of 800.

[0089] The final emulsion product has a specific gravity of 1.19 g / ml, a solid content of 28.6% w / w, and no demulsified powder on the surface of the emulsion.

[0090] Example 4

[0091] A method for preparing high-efficiency fusible polytetrafluoroethylene (PFA), the operating steps of which are:

[0092] S1: Add 3000 g of high-purity water to the polymerization kettle and start stirring, control the speed to 120 rpm, add 50 g of surfactant, 5 g of dispersing aid, 10 g of chain transfer agent, 40 g of perfluoroalkyl vinyl ether monomer, adjust the temperature of the polymerization kettle to 120°C, add 200 g of tetrafluoroethylene monomer, make the pressure in the reactor reach 5.0 MPa, add 10 g of initiator solution to the reactor, and initiate copolymerization;

[0093] S2: After the polymerization reaction starts, a gas mixture of tetrafluoroethylene and perfluoroalkyl vinyl ether is continuously added into the polymerization kettle, and the pressure of the reactor is maintained at 5.0 MPa. At the same time, the initiator solution is continuously added into the reactor at a constant rate, and the reaction temperature is controlled at 120°C. When the amount of mixed monomer added reaches 1200g, the addition of monomers and initiators is stopped to terminate the copolymerization reaction. After the unreacted monomers in the polymerization kettle are recovered, a fusible polytetrafluoroethylene (PFA) resin emulsion is obtained, and the emulsion is translucent milky white.

[0094] The surfactant is perfluoro-2,5-dimethyl-3,6-dioxano-nonanoic acid ammonium.

[0095] The surfactant is an aqueous solution with a concentration of 30%.

[0096] The chain transfer agent is n-butane.

[0097] The perfluoroalkyl vinyl ether is perfluoro-n-propyl vinyl ether.

[0098] The initiator is an aqueous solution of ammonium persulfate.

[0099] The concentration of the initiator solution is 5%.

[0100] The initiator addition rate is 10 g / h.

[0101] The ratio of tetrafluoroethylene to perfluoroalkyl vinyl ether in the mixed monomer is 25:1.

[0102] The preparation method of the dispersing aid is

[0103] H1: Add 17g 6-mercaptobenzo[C][1,2]oxaborocyclo-1(3H)-ol (CAS: 2130753-08-9), 5g 10,13-epoxy-10,12-octadecadienoic acid, 600g DMF, 15g triethylamine, react at 50°C for 150 minutes,

[0104] H2: 70 g of perfluoropolyether (meth)acrylate and 5 g of triethylamine were added, and the mixture was reacted at 80° C. for 180 minutes. DMF was then removed by reduced pressure distillation to obtain a dispersing aid.

[0105] The perfluoropolyether (meth)acrylate has a viscosity of 1000.

[0106] The final emulsion product has a specific gravity of 1.21 g / ml, a solid content of 33.1% w / w, and no demulsified powder on the surface of the emulsion.

[0107] Comparative Example

[0108] A method for preparing high-efficiency fusible polytetrafluoroethylene (PFA), the operating steps of which are:

[0109] S1: Add 2000 g of high-purity water to the polymerization kettle, start stirring, control the speed to 30 rpm, add 10 g of surfactant, add 2 g of chain transfer agent, add 5 g of perfluoroalkyl vinyl ether monomer, adjust the temperature of the polymerization kettle to 60°C, add 100 g of tetrafluoroethylene monomer, make the pressure in the reactor reach 1.5 MPa, add 3 g of initiator solution to the reactor, and initiate copolymerization;

[0110] S2: After the polymerization reaction starts, a gas mixture of tetrafluoroethylene and perfluoroalkyl vinyl ether is continuously added into the polymerization kettle, and the pressure of the reactor is maintained at 1.5 MPa. At the same time, the initiator solution is continuously added into the reactor at a constant rate, and the reaction temperature is controlled at 60°C. When the amount of mixed monomer added reaches 600g, the addition of monomers and initiators is stopped to terminate the copolymerization reaction. After the unreacted monomers in the polymerization kettle are recovered, a fusible polytetrafluoroethylene (PFA) resin emulsion is obtained, and the emulsion is translucent milky white.

[0111] The surfactant is ammonium perfluorooctanoate.

[0112] The surfactant is an aqueous solution with a concentration of 10%.

[0113] The chain transfer agent is propane.

[0114] The perfluoroalkyl vinyl ether is perfluoromethyl vinyl ether.

[0115] The initiator is an aqueous solution of potassium persulfate.

[0116] The concentration of the initiator solution is 1%.

[0117] The initiator addition rate is 3 g / h.

[0118] The ratio of tetrafluoroethylene to perfluoroalkyl vinyl ether in the mixed monomer is 8:1.

[0119] The final emulsion product has a specific gravity of 1.18 g / ml, a solid content of 22.0% w / w, and no demulsified powder on the surface of the emulsion.

[0120] It can be seen from the above specific implementation methods that this method effectively increases the solid content of the emulsion and improves production efficiency.

[0121] The applicant declares that the present invention is further illustrated by the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing high-efficiency fusible polytetrafluoroethylene (PFA), the operating steps of which are: S1: Add 2000-3000 parts of high-purity water to the polymerization kettle according to weight parts, start stirring, control the speed to 10-120rpm, add 10-50 parts of surfactant, 2-5 parts of dispersing aid, 0.01-10 parts of chain transfer agent, 5-40 parts of perfluoroalkyl vinyl ether monomer, adjust the temperature of the polymerization kettle to 60-120°C, add 100-200 parts of tetrafluoroethylene monomer, make the pressure in the reactor reach 1.5-5.0MPa, add 1-10 parts of initiator solution to the reactor to initiate copolymerization reaction; S2: After the polymerization reaction starts, a gas mixture of tetrafluoroethylene and perfluoroalkyl vinyl ether is continuously added into the polymerization kettle, and the pressure of the reactor is maintained at 1.5-5.0 MPa. At the same time, the initiator solution is continuously added into the reactor at a constant rate, and the reaction temperature is controlled at 60-120°C. When the amount of mixed monomers added reaches 600-1200 parts, the addition of monomers and initiators is stopped to terminate the copolymerization reaction. After the unreacted monomers in the polymerization kettle are recovered, a fusible polytetrafluoroethylene (PFA) resin emulsion is obtained, and the emulsion is translucent milky white.

2. The method for preparing high-efficiency fusible polytetrafluoroethylene (PFA) according to claim 1, characterized in that: The surfactant is one or more mixtures of ammonium perfluorooctanoate, ammonium perfluorooctane sulfonate, perfluorooctane sulfonamide, ammonium perfluorohexanoate, and perfluoro-2,5-dimethyl-3,6-dioxanononanoate.

3. The method for preparing high-efficiency fusible polytetrafluoroethylene (PFA) according to claim 1, characterized in that: The surfactant is an aqueous solution with a concentration of 10-30%.

4. The method for preparing high-efficiency fusible polytetrafluoroethylene (PFA) according to claim 1, characterized in that: The chain transfer agent is a straight alkane; the straight alkane molecular formula C n H 2n+2 , where n=1~4.

5. The method for preparing high-efficiency fusible polytetrafluoroethylene (PFA) according to claim 1, characterized in that: The perfluoroalkyl vinyl ether is a mixture of one or more of perfluoromethyl vinyl ether, perfluoroethyl vinyl ether and perfluoro-n-propyl vinyl ether.

6. The method for preparing high-efficiency fusible polytetrafluoroethylene (PFA) according to claim 1, characterized in that: The initiator is an aqueous solution or a mixed solution of potassium persulfate or ammonium persulfate.

7. The method for preparing high-efficiency fusible polytetrafluoroethylene (PFA) according to claim 1, characterized in that: The concentration of the initiator solution is 0.1-5%.

8. The method for preparing high-efficiency fusible polytetrafluoroethylene (PFA) according to claim 1, characterized in that: The initiator is added at a rate of 3 to 10 parts per hour.

9. The method for preparing high-efficiency fusible polytetrafluoroethylene (PFA) according to claim 1, characterized in that: The ratio of tetrafluoroethylene to perfluoroalkyl vinyl ether in the mixed monomer is 8-25.

10. The method for preparing high-efficiency fusible polytetrafluoroethylene (PFA) according to claim 1, characterized in that: The preparation method of the dispersing aid is H1: Add 10-17 parts of 6-mercaptobenzo[C][1,2]oxaborocyclo-1(3H)-ol, 2-5 parts of 10,13-epoxy-10,12-octadecadienoic acid, 500-600 parts of DMF, 10-15 parts of triethylamine, and react at 40-50°C for 100-150 minutes. H2: Add 50-70 parts of perfluoropolyether (meth)acrylate and 2-5 parts of triethylamine, react at 70-80° C. for 120-180 minutes, and then remove DMF by reduced pressure distillation to obtain a dispersing aid.

Images