CN-122006498-A - Preparation method of PTFE porous non-woven fiber membrane and PTFE porous non-woven fiber membrane

Abstract

The application is suitable for the technical field of organic film manufacturing, and provides a preparation method of a PTFE porous non-woven fiber film and the PTFE porous non-woven fiber film. The preparation method of the PTFE porous non-woven fiber membrane comprises the steps of uniformly mixing PTFE raw materials and salt particles, fibrillating the mixture to obtain a fibrillated mixture, carrying out fiber network strengthening treatment on the fibrillated mixture, carrying out calendaring molding to obtain a PTFE-salt particle composite self-supporting membrane, and removing salt particles in the PTFE-salt particle composite self-supporting membrane by utilizing a separation method corresponding to the salt particles according to the types of the salt to obtain the PTFE porous non-woven fiber membrane. The preparation method of the PTFE porous non-woven fiber membrane is simple in preparation process and low in preparation cost, and the prepared PTFE porous non-woven fiber membrane has higher performance.

Inventors

• TAN JIEWEN
• TANG WEI
• WANG SHIMING
• YANG KANG
• LING QI
• PAN ZEYAN
• ZHANG YUSHAN
• ZHANG JIAOJIAO
• TONG CHENG

Assignees

• 高能数造(西安)技术有限公司

Dates

Publication Date

20260512

Application Date

20260408

Claims (10)

1. 1. A method of making a porous nonwoven fibrous PTFE membrane, the method comprising: uniformly mixing PTFE raw materials with salt particles, and carrying out fibrillation treatment on the mixture to obtain a fibrillation mixture; Carrying out fiber network strengthening treatment on the fibrillated mixture, and carrying out calendaring molding to obtain a PTFE-salt particle composite self-supporting film; And removing the salt particles in the PTFE-salt particle composite self-supporting film by utilizing a separation method corresponding to the salt particles according to the salt types to obtain the PTFE porous non-woven fiber film.
2. 2. The method of claim 1, wherein the mass ratio of PTFE to salt particles ranges from 0.1% to 30%.
3. 3. The method of claim 1, wherein the salt species comprises a readily soluble salt or a readily decomposable salt; The soluble salt comprises sodium chloride, sodium sulfate, lithium bromide, lithium chloride, lithium sulfate, lithium ethoxide, sodium acetate or sodium methylsulfonate; The easily thermally decomposable salt comprises ammonium chloride, ammonium bromide, ammonium iodide, ammonium bicarbonate, ammonium carbonate, ammonium nitrate, ammonium acetate, ammonium benzoate, tetraethylammonium tetrafluoroborate or triethanolamine.
4. 4. The method of claim 1, wherein the fibrillating mixture is subjected to a fiber network strengthening treatment and calendaring to obtain the PTFE-salt particle composite self-supporting film, comprising: Kneading the fibrillated mixture at a first preset temperature for a preset period of time to obtain a kneaded fibrillated mixture; continuously rolling the kneaded fibrillated mixture at a second preset temperature, and rolling the kneaded fibrillated mixture to a preset thickness to obtain the PTFE-salt particle composite self-supporting film.
5. 5. The method of claim 4, wherein the first preset temperature and the second preset temperature range from 25 ℃ to 400 ℃; The range of the preset time length is 0.5 to 10 minutes; the preset thickness ranges from 1 μm to 2000 μm.
6. 6. The method of claim 5, wherein the PTFE porous nonwoven fibrous membrane obtained after removal of the salt particles in the PTFE-salt particle composite self-supporting membrane has a membrane thickness of less than or equal to 5 μm.
7. 7. The method according to any one of claims 1 to 6, wherein the removing the salt particles in the PTFE-salt particle composite self-supporting film according to the kind of the salt using a separation method corresponding to the salt particles to obtain the PTFE porous nonwoven fibrous film comprises: When the salt is a type that is easily soluble in a solvent, the separation method includes washing the PTFE-salt particle composite self-supporting membrane with a solvent that can dissolve the salt particles to remove the salt particles in the PTFE-salt particle composite self-supporting membrane, thereby obtaining the PTFE porous nonwoven fibrous membrane; When the salt is of a type which is easy to thermally decompose, the separation method comprises the steps of heating the PTFE-salt particle composite self-supporting film to thermally decompose the salt particles so as to remove the salt particles in the PTFE-salt particle composite self-supporting film, and obtaining the PTFE porous non-woven fibrous film.
8. 8. The method of claim 7, wherein washing the PTFE-salt particle composite self-supporting film with a solvent that dissolves the salt particles to remove the salt particles in the PTFE-salt particle composite self-supporting film, to obtain the PTFE porous nonwoven fibrous film, comprises: washing the PTFE-salt particle composite self-supporting film for a plurality of times by using a solvent capable of dissolving the salt particles, and removing the salt particles in the PTFE-salt particle composite self-supporting film to obtain PTFE self-supporting film gel; evaporating the PTFE self-supporting film gel to dryness to obtain the PTFE porous non-woven fiber film.
9. 9. The method of claim 7, wherein after obtaining the PTFE porous nonwoven fibrous membrane, the method further comprises: And extruding and thinning the PTFE porous non-woven fiber membrane, and/or sintering the PTFE self-supporting membrane under preset conditions to obtain the reinforced PTFE porous non-woven fiber membrane.
10. 10. A porous non-woven fibrous PTFE membrane, characterized in that it is produced by the process for producing a porous non-woven PTFE membrane according to any one of claims 1 to 9, the porous non-woven PTFE membrane being a self-supporting membrane; the PTFE porous non-woven fiber membrane is provided with a three-dimensional porous network structure formed by interweaving PTFE continuous fibers, the continuous fibers are formed by carrying out fibrillation treatment, breaking and stretching on PTFE materials, the continuous fibers are continuous stretched filiform or ribbon-shaped fibers, and the diameter of the PTFE continuous fibers is 200 nm-800 nm.

Description

Preparation method of PTFE porous non-woven fiber membrane and PTFE porous non-woven fiber membrane Technical Field The application belongs to the technical field of organic film manufacturing, and particularly relates to a preparation method of a PTFE porous non-woven fiber film and the PTFE porous non-woven fiber film. Background Polytetrafluoroethylene (PTFE) is a core substrate for preparing a high-performance porous membrane material because of its excellent chemical stability, high and low temperature resistance, water and oil repellency, low dielectric constant, and good physiological inertia. PTFE is widely applied to the fields of air and water filtration, waterproof ventilation, sea water desalination, lithium battery diaphragm, chemical separation and the like. PTFE has the property of being insoluble and infusible, which makes its fibrous membrane preparation process extremely complex. At present, common PTFE fiber membrane preparation methods comprise an electrostatic spinning method, a membrane splitting method and a template method. The PTFE fiber membrane prepared by the electrostatic spinning method has insufficient mechanical properties, the thickness of the PTFE fiber membrane prepared by the membrane splitting method is limited, the fiber membrane material with the thickness of less than 5 mu m is difficult to prepare, and the template is difficult to thoroughly remove when the PTFE porous fiber membrane prepared by the template method is used. Therefore, the existing PTFE fiber membrane preparation method has the problems of high preparation cost, low fibrosis degree, poor mechanical property and the like, the preparation process is complex, and the prepared PTFE fiber membrane is difficult to meet the requirements. Therefore, a process for preparing a fibrous membrane is needed to solve the above manufacturing problems. Disclosure of Invention The embodiment of the application provides a preparation method of a PTFE porous non-woven fiber membrane and the PTFE porous non-woven fiber membrane, which can utilize salt particles as a fiberizing auxiliary agent and a pore-forming agent to realize efficient fiberization of PTFE and prepare the PTFE porous non-woven fiber membrane with higher performance. According to a first aspect, the embodiment of the application provides a preparation method of a PTFE porous non-woven fiber membrane, which comprises the steps of uniformly mixing PTFE raw materials with salt particles, fibrillating the mixture to obtain a fibrillated mixture, carrying out fiber network strengthening treatment on the fibrillated mixture, and carrying out calendaring molding to obtain the PTFE-salt particle composite self-supporting membrane, and removing salt particles in the PTFE-salt particle composite self-supporting membrane by utilizing a separation method corresponding to the salt particles according to the type of the salt to obtain the PTFE porous non-woven fiber membrane. In this example, a fibrillated mixture is obtained by first fibrillating a PTFE raw material with salt particles. And then, carrying out fiber network strengthening treatment on the fibrillated mixture to obtain the PTFE-salt particle composite self-supporting film. And finally, removing salt particles in the PTFE-salt particle composite self-supporting film by adopting a corresponding separation mode according to the properties of the salt particles, so as to obtain the prepared PTFE porous non-woven fibrous film. In the fibrillation process, the salt particles not only can be used as a transmission medium of shearing force (namely as a fibrillation aid), but also can be used as a pore-forming agent to avoid the premature entanglement of PTFE fibers, so that the efficient fibrillation of PTFE is realized. The PTFE-salt particle composite self-supporting film obtained by the method has a framework structure formed by interweaving fibers, is automatically contracted and thinned in the process of removing salt particles, and can maintain a self-supporting structure after thinning. The preparation method of the PTFE porous non-woven fiber membrane is simple in preparation process and low in preparation cost, and the prepared PTFE porous non-woven fiber membrane has higher performance. In some embodiments, the mass ratio of PTFE to the salt particles ranges from 0.1% to 30%. In some embodiments, the salt species comprises an easily soluble salt or an easily decomposable salt, the easily decomposable salt comprising sodium chloride, sodium sulfate, lithium bromide, lithium chloride, lithium sulfate, lithium ethoxide, sodium acetate, or sodium methylsulfonate, and the easily thermally decomposable salt comprising ammonium chloride, ammonium bromide, ammonium iodide, ammonium bicarbonate, ammonium carbonate, ammonium nitrate, ammonium acetate, ammonium benzoate, tetraethylammonium tetrafluoroborate, or triethanolamine. In some embodiments, the fiber network strengthening treatment is performed on the fi