阅读说明：本技术 一种纤维级ptfe纺丝乳液的制备方法 (Preparation method of fiber-grade PTFE spinning emulsion ) 是由 司耀俊 徐�明 钱厚琴 于 2021-06-30 设计创作，主要内容包括：本发明公开了一种纤维级PTFE纺丝乳液的制备方法,将原料以去离子水的加入量为基准按重份计；将原料中去离子水、石蜡放入反应釜中进行抽空置换处理,在处理时的聚合起始温度为60℃,过程中保持在65～70℃,然后加入四氟乙烯恒压反应；将原料中过硫酸铵、丙烯酸、全氟聚醚羧酸铵和异丙醇、亚硫酸氢钠计量加入到反应釜内；当计量示数达到指定值时,再加入全氟聚醚羧酸铵和十二烷基磺酸钠加入到反应釜内；当气体质量流量计的示数到指定值时终止反应,冷却分离石蜡,通氮除氧,用质量分数为30%氢氧化钠水溶液中和至pH值为7～7.5,加热去除低沸点助剂并用浓缩工艺将PTFE树脂固含量提至45～60%。(The invention discloses a preparation method of fiber-grade PTFE spinning emulsion, which comprises the following steps of (1) taking the addition of deionized water as a reference by weight; putting deionized water and paraffin in the raw materials into a reaction kettle for evacuation and replacement treatment, wherein the polymerization initial temperature during treatment is 60 ℃, the polymerization initial temperature is kept at 65-70 ℃ in the process, and then adding tetrafluoroethylene for constant-pressure reaction; ammonium persulfate, acrylic acid, ammonium perfluoropolyether carboxylate, isopropanol and sodium bisulfite in the raw materials are metered into a reaction kettle; when the measured number reaches a specified value, adding ammonium perfluoropolyether carboxylate and sodium dodecyl sulfate into the reaction kettle; stopping the reaction when the indication value of the gas mass flow meter reaches a specified value, cooling and separating paraffin, introducing nitrogen to remove oxygen, neutralizing with 30% by mass of sodium hydroxide aqueous solution until the pH value is 7-7.5, heating to remove low-boiling-point auxiliary agents, and increasing the solid content of the PTFE resin to 45-60% by using a concentration process.)

1. A preparation method of fiber-grade PTFE spinning emulsion is characterized by comprising the following steps:

firstly, preparing raw materials: deionized water is used as a medium, ammonium perfluoropolyether carboxylate is used as a first emulsifier, paraffin is used as a stabilizer, ammonium persulfate is used as an initiator, sodium bisulfite is used as a reducing agent, sodium dodecyl sulfate is used as a second emulsifier, acrylic acid is used as a pH regulator, isopropanol is used as a chain transfer agent, and tetrafluoroethylene is used as a polymerization monomer to prepare dispersed polytetrafluoroethylene emulsion through polymerization;

secondly, when the addition amount of the deionized water is 100 parts by weight, the ammonium perfluoropolyether carboxylate is 1.43 multiplied by 10^-1～4.3×10^-15 portions of paraffin and 1.14 multiplied by 10 portions of ammonium persulfate^-2Sodium bisulfite 2.28X 10^-2The part by weight of the sodium dodecyl sulfate is 2.14 multiplied by 10^-2Part of acrylic acid is 2.14 multiplied by 10^-2Part(s) of isopropanol is 1.07 multiplied by 10^-2The addition amount of tetrafluoroethylene is controlled according to the product requirements, and the addition amount of the tetrafluoroethylene is 15-30 parts according to the product in view of raw material loss and emulsion stability;

step three, putting the deionized water and the paraffin wax in the step two into a reaction kettle for evacuation and replacement treatment,

the polymerization starting temperature in the treatment is 60 ℃, the polymerization process is kept at 65-70 ℃, then tetrafluoroethylene is added, the reaction pressure in the addition is a fixed value with the gauge pressure of 1.6-3.0 MPa, and the reaction is carried out under constant pressure;

step four, adding the ammonium persulfate, the acrylic acid, the ammonium perfluoropolyether carboxylate and the isopropanol in the step two into the reaction kettle in the step three through a metering pump;

in the fifth step, sodium bisulfite is added to 2.28 multiplied by 10^-2Adding the components into a reaction kettle in the third step through a metering pump;

step six, when the indication number of the gas mass flow meter reaches a specified value, adding ammonium perfluoropolyether carboxylate and sodium dodecyl sulfate into the reaction kettle by using a metering pump;

step seven, stopping the reaction when the indication number of the gas mass flow meter reaches the final specified value;

and step seven, cooling the temperature of the reaction kettle after polymerization is finished to separate paraffin, introducing nitrogen to remove oxygen, neutralizing with 30% by mass of sodium hydroxide aqueous solution until the pH value is 7-7.5, heating to remove low-boiling-point auxiliaries, and increasing the solid content of the PTFE resin to 45-60% by using a concentration process.

2. The preparation method of the fiber-grade PTFE spinning emulsion according to claim 1, wherein when the volume of the reaction kettle is 100L, 65L of deionized water and 3.5kg of liquid paraffin are added into the reaction kettle with the volume of 100L, the reaction kettle is evacuated and replaced, the temperature is controlled at 60 ℃, the reaction pressure is adjusted to 2.0MPa and maintained when the tetrafluoroethylene is added into the reaction kettle, 7.4g of ammonium persulfate, 15g of acrylic acid, 120g of ammonium perfluoropolyether carboxylate and 7.5g of isopropanol are added into the reaction kettle by a metering pump; mixing 1.48L of sodium bisulfite solution with the mass percentage concentration of 1 percent, and continuously adding the sodium bisulfite solution into the reaction kettle by a metering pump at 0.7L/h; when the reading of the gas mass flow meter reaches 7kg, adding 80g of ammonium perfluoropolyether carboxylate solution and 0.72L of sodium dodecyl sulfate solution with the mass percentage concentration of 2% into a reaction kettle by using a metering pump; stopping the reaction when the reading of the gas mass flow meter reaches 21 kg; cooling the polymerization kettle to below 40 ℃, transferring the emulsion to a concentration tank, introducing nitrogen to remove oxygen, neutralizing the emulsion with 30% by mass of sodium hydroxide aqueous solution until the pH value is 7-7.5, heating to remove the low-boiling-point auxiliary agent, and increasing the solid content of the PTFE resin to 60% by using a concentration process.

3. The preparation method of the fiber-grade PTFE spinning emulsion according to claim 1, wherein when the volume of the reaction kettle is 100L, 65L of deionized water and 3.5kg of liquid paraffin are added into the reaction kettle with the volume of 100L, the reaction kettle is evacuated and replaced, the temperature is controlled at 60 ℃, the reaction pressure is adjusted to 1.6MPa and maintained when the tetrafluoroethylene is added into the reaction kettle, 7.4g of ammonium persulfate, 15g of acrylic acid, 90g of ammonium perfluoropolyether carboxylate and 7.5g of isopropanol are added into the reaction kettle by a metering pump; mixing 1.48L of sodium bisulfite solution with the mass percentage concentration of 1 percent, and continuously adding the sodium bisulfite solution into the reaction kettle by a metering pump at 0.7L/h; when the reading of the gas mass flow meter reaches 7kg, adding 80g of ammonium perfluoropolyether carboxylate solution and 0.72L of sodium dodecyl sulfate solution with the mass percentage concentration of 2% into a reaction kettle by using a metering pump; stopping the reaction when the reading of the gas mass flow meter reaches 12 kg; cooling the polymerization kettle to below 40 ℃, transferring the emulsion to a concentration tank, introducing nitrogen to remove oxygen, neutralizing the emulsion with 30% by mass of sodium hydroxide aqueous solution until the pH value is 7-7.5, heating to remove the low-boiling-point auxiliary agent, and increasing the solid content of the PTFE resin to 50% by using a concentration process.

4. The preparation method of the fiber-grade PTFE spinning emulsion according to claim 1, wherein when the volume of the reaction kettle is 100L, 65L of deionized water and 3.5kg of liquid paraffin are added into the reaction kettle with the volume of 100L, the reaction kettle is evacuated and replaced, the temperature is controlled at 60 ℃, the reaction pressure is adjusted to 3.0MPa and maintained when the tetrafluoroethylene is added into the reaction kettle, 7.4g of ammonium persulfate, 15g of acrylic acid, 180g of ammonium perfluoropolyether carboxylate and 7.5g of isopropanol are added into the reaction kettle by a metering pump; mixing 1.48L of sodium bisulfite solution with the mass percentage concentration of 1 percent, and continuously adding the sodium bisulfite solution into the reaction kettle by a metering pump at 0.7L/h; when the reading of the gas mass flow meter reaches 7kg, adding 80g of ammonium perfluoropolyether carboxylate solution and 0.72L of sodium dodecyl sulfate solution with the mass percentage concentration of 2% into a reaction kettle by using a metering pump; stopping the reaction when the reading of the gas mass flow meter reaches 18 kg; cooling the polymerization kettle to below 40 ℃, transferring the emulsion to a concentration tank, introducing nitrogen to remove oxygen, neutralizing the emulsion with 30% by mass of sodium hydroxide aqueous solution until the pH value is 7-7.5, heating to remove the low-boiling-point auxiliary agent, and increasing the solid content of the PTFE resin to 45% by using a concentration process.

5. The process for preparing fiber-grade PTFE spinning emulsion according to any one of claims 1 to 4, wherein the gas mass flow meter is connected with the reaction kettle by a one-way check valve, so that the gas can only flow from the metering tank to the reaction kettle in one way, and the conductivity of the used deionized water is 0.7 μ S/m.

Technical Field

The invention relates to the technical field of fluorine-containing plastics and preparation methods thereof, in particular to a preparation method of fiber-grade PTFE spinning emulsion.

Background

The PTFE fiber has excellent performance, does not absorb water, has good non-adhesiveness, lubricity and air tightness, improves the defect of poor oxidation resistance, and still has excellent chemical corrosion resistance at high temperature, so the filter material containing the PTFE fiber component is widely applied to filter materials under the environments of high temperature, strong acid, alkali and the like, and becomes a preferred filter material under the special working conditions of waste incineration, blast furnace gas purification, cement kiln tail gas and the like. The emulsion spinning method is the main method adopted in industry, but because the affinity between the PTFE emulsion and a fiber-forming carrier is not strong, the carrier is usually difficult to be completely and uniformly mixed with the PTFE emulsion, and defect points exist, so that the prepared fiber has smaller titer and lower strength.

Disclosure of Invention

The invention provides a preparation method of fiber-grade PTFE spinning emulsion, which can solve the technical problem of fiber defect points caused by weak affinity between PTFE and a fiber-forming carrier, thereby improving the fiber strength and increasing the fiber fineness.

The invention adopts the following technical scheme: a preparation method of fiber-grade PTFE spinning emulsion comprises the following steps: firstly, preparing raw materials: deionized water is used as a medium, ammonium perfluoropolyether carboxylate is used as a first emulsifier, paraffin is used as a stabilizer, ammonium persulfate is used as an initiator, sodium bisulfite is used as a reducing agent, sodium dodecyl sulfate is used as a second emulsifier, acrylic acid is used as a pH regulator, isopropanol is used as a chain transfer agent, and tetrafluoroethylene is used as a polymerization monomer to prepare dispersed polytetrafluoroethylene emulsion through polymerization;

secondly, when the addition amount of the deionized water is 100 parts by weight, the ammonium perfluoropolyether carboxylate is 1.43 multiplied by 10^-1～4.3×10^-15 portions of paraffin and 1.14 multiplied by 10 portions of ammonium persulfate^-2Sodium bisulfite 2.28X 10^-2The part by weight of the sodium dodecyl sulfate is 2.14 multiplied by 10^-2Part of acrylic acid is 2.14 multiplied by 10^-2Part(s) of isopropanol is 1.07 multiplied by 10^-2The addition amount of tetrafluoroethylene is controlled according to the product requirements, and the addition amount of the tetrafluoroethylene is 15-30 parts according to the product in view of raw material loss and emulsion stability;

step three, putting the deionized water and the paraffin wax in the step two into a reaction kettle for evacuation and replacement treatment,

the polymerization starting temperature in the treatment is 60 ℃, the polymerization process is kept at 65-70 ℃, then tetrafluoroethylene is added, the reaction pressure in the addition is a fixed value with the gauge pressure of 1.6-3.0 MPa, and the reaction is carried out under constant pressure;

step four, adding the ammonium persulfate, the acrylic acid, the ammonium perfluoropolyether carboxylate and the isopropanol in the step two into the reaction kettle in the step three through a metering pump;

in the fifth step, sodium bisulfite is added to 2.28 multiplied by 10^-2Adding the components into a reaction kettle in the third step through a metering pump;

step six, when the indication number of the gas mass flow meter reaches a specified value, adding ammonium perfluoropolyether carboxylate and sodium dodecyl sulfate into the reaction kettle by using a metering pump;

step seven, stopping the reaction when the indication number of the gas mass flow meter reaches the final specified value;

and step seven, cooling the temperature of the reaction kettle after polymerization is finished to separate paraffin, introducing nitrogen to remove oxygen, neutralizing with 30% by mass of sodium hydroxide aqueous solution until the pH value is 7-7.5, heating to remove low-boiling-point auxiliaries, and increasing the solid content of the PTFE resin to 45-60% by using a concentration process.

When the volume of the reaction kettle is 100L, 65L of deionized water and 3.5kg of liquid paraffin are added into the reaction kettle with the volume of 100L, the reaction kettle is evacuated and replaced, the temperature is controlled at 60 ℃, the reaction pressure is adjusted to 2.0MPa and maintained in the whole process when tetrafluoroethylene is added into the reaction kettle, and 7.4g of ammonium persulfate, 15g of acrylic acid, 120g of ammonium perfluoropolyether carboxylate and 7.5g of isopropanol are added into the reaction kettle by a metering pump; mixing 1.48L of sodium bisulfite solution with the mass percentage concentration of 1 percent, and continuously adding the sodium bisulfite solution into the reaction kettle by a metering pump at 0.7L/h; when the reading of the gas mass flow meter reaches 7kg, adding 80g of ammonium perfluoropolyether carboxylate solution and 0.72L of sodium dodecyl sulfate solution with the mass percentage concentration of 2% into a reaction kettle by using a metering pump; stopping the reaction when the reading of the gas mass flow meter reaches 21 kg; cooling the polymerization kettle to below 40 ℃, transferring the emulsion to a concentration tank, introducing nitrogen to remove oxygen, neutralizing the emulsion with 30% by mass of sodium hydroxide aqueous solution until the pH value is 7-7.5, heating to remove the low-boiling-point auxiliary agent, and increasing the solid content of the PTFE resin to 60% by using a concentration process.

When the volume of the reaction kettle is 100L, 65L of deionized water and 3.5kg of liquid paraffin are added into the reaction kettle with the volume of 100L, the reaction kettle is evacuated and replaced, the temperature is controlled at 60 ℃, the reaction pressure is adjusted to 1.6MPa and maintained in the whole process when tetrafluoroethylene is added into the reaction kettle, and 7.4g of ammonium persulfate, 15g of acrylic acid, 90g of ammonium perfluoropolyether carboxylate and 7.5g of isopropanol are added into the reaction kettle by a metering pump; mixing 1.48L of sodium bisulfite solution with the mass percentage concentration of 1 percent, and continuously adding the sodium bisulfite solution into the reaction kettle by a metering pump at 0.7L/h; when the reading of the gas mass flow meter reaches 7kg, adding 80g of ammonium perfluoropolyether carboxylate solution and 0.72L of sodium dodecyl sulfate solution with the mass percentage concentration of 2% into a reaction kettle by using a metering pump; stopping the reaction when the reading of the gas mass flow meter reaches 12 kg; cooling the polymerization kettle to below 40 ℃, transferring the emulsion to a concentration tank, introducing nitrogen to remove oxygen, neutralizing the emulsion with 30% by mass of sodium hydroxide aqueous solution until the pH value is 7-7.5, heating to remove the low-boiling-point auxiliary agent, and increasing the solid content of the PTFE resin to 50% by using a concentration process.

When the volume of the reaction kettle is 100L, 65L of deionized water and 3.5kg of liquid paraffin are added into the reaction kettle with the volume of 100L, the reaction kettle is evacuated and replaced, the temperature is controlled at 60 ℃, the reaction pressure is adjusted to 3.0MPa and maintained in the whole process when tetrafluoroethylene is added into the reaction kettle, and 7.4g of ammonium persulfate, 15g of acrylic acid, 180g of ammonium perfluoropolyether carboxylate and 7.5g of isopropanol are added into the reaction kettle by a metering pump; mixing 1.48L of sodium bisulfite solution with the mass percentage concentration of 1 percent, and continuously adding the sodium bisulfite solution into the reaction kettle by a metering pump at 0.7L/h; when the reading of the gas mass flow meter reaches 7kg, adding 80g of ammonium perfluoropolyether carboxylate solution and 0.72L of sodium dodecyl sulfate solution with the mass percentage concentration of 2% into a reaction kettle by using a metering pump; stopping the reaction when the reading of the gas mass flow meter reaches 18 kg; cooling the polymerization kettle to below 40 ℃, transferring the emulsion to a concentration tank, introducing nitrogen to remove oxygen, neutralizing the emulsion with 30% by mass of sodium hydroxide aqueous solution until the pH value is 7-7.5, heating to remove the low-boiling-point auxiliary agent, and increasing the solid content of the PTFE resin to 45% by using a concentration process.

The gas mass flow meter is connected with the reaction kettle by adopting a one-way check valve, so that gas can only flow from the metering tank to the reaction kettle in a one-way mode, and the conductivity of the used deionized water is 0.7 mu S/m.

The invention has the following beneficial effects: the invention adopts a fiber-grade PTFE spinning emulsion preparation process combining a redox initiation system and a double emulsifier, solves the technical problem that the existing PTFE emulsion has weak affinity with a fiber-forming carrier to cause fiber defect points, belongs to the technical field of fluorine-containing plastics and preparation methods thereof, and is characterized in that deionized water is used as a medium, ammonium perfluoropolyether carboxylate is used as a first emulsifier, paraffin is used as a stabilizer, ammonium persulfate is used as an initiator, sodium bisulfite is used as a reducing agent, sodium dodecyl sulfate is used as a second emulsifier, acrylic acid is used as a pH regulator, isopropanol is used as a chain transfer agent, tetrafluoroethylene is used as a polymerization monomer, constant-pressure polymerization is carried out, paraffin is cooled and separated, nitrogen is introduced to remove oxygen, neutralization is carried out, a low-boiling-point auxiliary agent is removed by heating, and the solid content of PTFE resin is increased to 45-60% by a concentration process; the redox initiation system and the chain transfer agent reduce the difference of molecular weight distribution, the organic acid improves the viscosity of the emulsion while adjusting the pH to be beneficial to dipping and adhesion, the organic acid improves the viscosity of the emulsion while adjusting the pH to be beneficial to carrier adhesion, and the double-emulsifier combination enables the emulsion obtained by polymerization to have the stability of the emulsion and the affinity to a fiber forming carrier, thereby solving the occurrence rate of fiber defect points.

Detailed Description

The invention provides a preparation method of fiber-grade PTFE spinning emulsion, which is characterized by comprising the following steps: firstly, preparing raw materials: deionized water is used as a medium, ammonium perfluoropolyether carboxylate is used as a first emulsifier, paraffin is used as a stabilizer, ammonium persulfate is used as an initiator, sodium bisulfite is used as a reducing agent, sodium dodecyl sulfate is used as a second emulsifier, acrylic acid is used as a pH regulator, isopropanol is used as a chain transfer agent, and tetrafluoroethylene is used as a polymerization monomer to prepare dispersed polytetrafluoroethylene emulsion through polymerization; secondly, when the addition amount of the deionized water is 100 parts by weight, the ammonium perfluoropolyether carboxylate is 1.43 multiplied by 10^-1～4.3×10^-15 portions of paraffin and 1.14 multiplied by 10 portions of ammonium persulfate^-2Sodium bisulfite 2.28X 10^-2The part by weight of the sodium dodecyl sulfate is 2.14 multiplied by 10^-2Part of acrylic acid is 2.14 multiplied by 10^-2Part(s) of isopropanol is 1.07 multiplied by 10^-2The addition amount of tetrafluoroethylene is controlled according to the product requirements, and the addition amount of the tetrafluoroethylene is 15-30 parts according to the product in view of raw material loss and emulsion stability;

step three, putting the deionized water and the paraffin wax in the step two into a reaction kettle for evacuation and replacement treatment,

the polymerization starting temperature in the treatment is 60 ℃, the polymerization process is kept at 65-70 ℃, then tetrafluoroethylene is added, the reaction pressure in the addition is a fixed value with the gauge pressure of 1.6-3.0 MPa, and the reaction is carried out under constant pressure; step four, adding the ammonium persulfate, the acrylic acid, the ammonium perfluoropolyether carboxylate and the isopropanol in the step two into the reaction kettle in the step three through a metering pump; in the fifth step, sodium bisulfite is added to 2.28 multiplied by 10^-2Adding the components into a reaction kettle in the third step through a metering pump; step six, when the indication number of the gas mass flow meter reaches a specified value, adding ammonium perfluoropolyether carboxylate and sodium dodecyl sulfate into the reaction kettle by using a metering pump; step seven, stopping the reaction when the indication number of the gas mass flow meter reaches the final specified value; and step seven, cooling the temperature of the reaction kettle after polymerization to separate paraffin, introducing nitrogen to remove oxygen, neutralizing with 30 mass percent sodium hydroxide aqueous solution until the pH value is 7-7.5, heating to remove low-boiling-point auxiliary agents, increasing the solid content of the PTFE resin to 45-60% by using a concentration process, connecting a gas mass flow meter and the reaction kettle by using a one-way check valve, enabling the gas to flow from a metering tank to the reaction kettle in a one-way manner only, and enabling the conductivity of the used deionized water to be 0.7 mu S/m.

The following examples further illustrate the present invention and are intended to enable one of ordinary skill in the art to understand and practice the present invention. It is to be noted, however, that the present invention is not limited to the preferred embodiments disclosed, and that any obvious modifications or equivalents thereof, based on the teachings of the present invention, should also be considered as falling within the scope of the present invention.

In the first embodiment, when the volume of the reaction kettle is 100L, 65L of deionized water and 3.5kg of liquid paraffin are added into the reaction kettle with the volume of 100L, the reaction kettle is evacuated and replaced, the temperature is controlled at 60 ℃, the reaction pressure is adjusted to 2.0MPa and maintained during the whole process when tetrafluoroethylene is added into the reaction kettle, and 7.4g of ammonium persulfate, 15g of acrylic acid, 120g of ammonium perfluoropolyether carboxylate and 7.5g of isopropanol are added into the reaction kettle by a metering pump; mixing 1.48L of sodium bisulfite solution with the mass percentage concentration of 1 percent, and continuously adding the sodium bisulfite solution into the reaction kettle by a metering pump at 0.7L/h; when the reading of the gas mass flow meter reaches 7kg, adding 80g of ammonium perfluoropolyether carboxylate solution and 0.72L of sodium dodecyl sulfate solution with the mass percentage concentration of 2% into a reaction kettle by using a metering pump; stopping the reaction when the reading of the gas mass flow meter reaches 21 kg; cooling the polymerization kettle to below 40 ℃, transferring the emulsion to a concentration tank, introducing nitrogen to remove oxygen, neutralizing the emulsion with 30% by mass of sodium hydroxide aqueous solution until the pH value is 7-7.5, heating to remove the low-boiling-point auxiliary agent, and increasing the solid content of the PTFE resin to 60% by using a concentration process. In this example, the emulsion viscosity was measured to be 0.022 pas, the average particle diameter was measured to be 0.15 μm, and the affinity of the carrier was verified by a viscose immersion test, and the appearance was fully coated without exposed spots.

Example two, when the volume of the reaction kettle of this example is 100L, 65L of deionized water and 3.5kg of liquid paraffin are added into the reaction kettle with the volume of 100L, the reaction kettle is evacuated and replaced, the temperature is controlled at 60 ℃, the reaction pressure is adjusted to 1.6MPa and maintained during the whole process when tetrafluoroethylene is added into the reaction kettle, and 7.4g of ammonium persulfate, 15g of acrylic acid, 90g of ammonium perfluoropolyether carboxylate and 7.5g of isopropanol are added into the reaction kettle by a metering pump; mixing 1.48L of sodium bisulfite solution with the mass percentage concentration of 1 percent, and continuously adding the sodium bisulfite solution into the reaction kettle by a metering pump at 0.7L/h; when the reading of the gas mass flow meter reaches 7kg, adding 80g of ammonium perfluoropolyether carboxylate solution and 0.72L of sodium dodecyl sulfate solution with the mass percentage concentration of 2% into a reaction kettle by using a metering pump; stopping the reaction when the reading of the gas mass flow meter reaches 12 kg; cooling the polymerization kettle to below 40 ℃, transferring the emulsion to a concentration tank, introducing nitrogen to remove oxygen, neutralizing the emulsion with 30% by mass of sodium hydroxide aqueous solution until the pH value is 7-7.5, heating to remove the low-boiling-point auxiliary agent, and increasing the solid content of the PTFE resin to 50% by using a concentration process. In this example, the emulsion viscosity was measured to be 0.016 pas and the average particle diameter was measured to be 0.16 μm, and the affinity of the carrier was verified by a viscose immersion test, and the appearance was fully coated without exposed spots.

Example three, when the volume of the reaction kettle of this example is 100L, 65L of deionized water and 3.5kg of liquid paraffin are added into the reaction kettle with the volume of 100L, the reaction kettle is evacuated and replaced, the temperature is controlled at 60 ℃, the reaction pressure is adjusted to 3.0MPa and maintained throughout the process when tetrafluoroethylene is added into the reaction kettle, and 7.4g of ammonium persulfate, 15g of acrylic acid, 180g of ammonium perfluoropolyether carboxylate and 7.5g of isopropanol are added into the reaction kettle by a metering pump; mixing 1.48L of sodium bisulfite solution with the mass percentage concentration of 1 percent, and continuously adding the sodium bisulfite solution into the reaction kettle by a metering pump at 0.7L/h; when the reading of the gas mass flow meter reaches 7kg, adding 80g of ammonium perfluoropolyether carboxylate solution and 0.72L of sodium dodecyl sulfate solution with the mass percentage concentration of 2% into a reaction kettle by using a metering pump; stopping the reaction when the reading of the gas mass flow meter reaches 18 kg; cooling the polymerization kettle to below 40 ℃, transferring the emulsion to a concentration tank, introducing nitrogen to remove oxygen, neutralizing the emulsion with 30% by mass of sodium hydroxide aqueous solution until the pH value is 7-7.5, heating to remove the low-boiling-point auxiliary agent, and increasing the solid content of the PTFE resin to 45% by using a concentration process. In this example, the emulsion viscosity was measured to be 0.017 pas and the average particle size was measured to be 0.16 μm, and the carrier affinity, appearance full coating and no exposed point were verified by viscose immersion test.