A kind of preparation method of polytetrafluoroethylene film

A technology of polytetrafluoroethylene membrane and polytetrafluoroethylene, which is applied in the field of preparation of hydrophobic membrane materials, can solve the problems of only focusing on the removal of fiber-forming templates, and achieve the effect of uniform fiber shape, improved strength and toughness, and intact surface

Active Publication Date: 2018-02-23
四川百途环保材料科技有限公司 +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

These reports all involve the step of high temperature sintering to remove the fiber-forming support, but these sintering processes only focus on the removal of the fiber-forming template

Method used

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  • A kind of preparation method of polytetrafluoroethylene film

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Comparison scheme
Effect test

Embodiment 1

[0027] The polytetrafluoroethylene emulsion with a solid content of 60% is added dropwise to an aqueous solution of polyvinyl alcohol with a mass fraction of 12%, and stirred evenly to form a spinning solution. Then the polytetrafluoroethylene precursor film was fabricated by electrospinning method. Winding on a cylindrical support mold with a diameter of 5cm, winding 5 layers, and sending it to a tube furnace with nitrogen gas, the temperature of the sintering process is controlled by a program, and the temperature is raised from room temperature to 110°C at 10°C / min, kept at 110°C for 90min, and at 7°C The heating rate is raised from 110°C to 290°C / min, the temperature is kept at 290°C for 100 minutes, the temperature is raised from 290°C to 380°C, the heating rate is 6°C / min, and the temperature is kept for 60 minutes. After cooling, take it out and pull out the cylindrical support mold to obtain a cylindrical polytetrafluoroethylene membrane with a thickness of 156 μm, whi...

Embodiment 2

[0029]The polytetrafluoroethylene emulsion with a solid content of 60% was added dropwise to an aqueous solution of polyacrylic acid with a mass fraction of 9%, and stirred evenly to prepare a spinning solution. Then the polytetrafluoroethylene precursor film was fabricated by electrospinning method. Winding on a cylindrical support mold with a diameter of 5cm, winding 5 layers, and sending it to a tube furnace with nitrogen gas. The temperature of the sintering process is controlled by a program. / min The heating rate is raised from 90°C to 260°C, the temperature is kept at 260°C for 120 minutes, the temperature is raised from 260°C to 375°C, the heating rate is 8°C / min, and the temperature is kept for 115 minutes. After cooling, take it out and pull out the cylindrical support mold to obtain a cylindrical polytetrafluoroethylene membrane with a thickness of 165um, which can be cut to obtain a flat porous membrane. The membrane has a hydrophobic contact angle of 159°, a poro...

Embodiment 3

[0031] The polytetrafluoroethylene emulsion with a solid content of 60% was added dropwise to a sodium alginate aqueous solution with a mass fraction of 5%, and stirred evenly to prepare a spinning solution. Then the polytetrafluoroethylene precursor film was fabricated by electrospinning method. Winding on a cylindrical support mold with a diameter of 5cm, winding 5 layers, and sending it to a tube furnace with nitrogen gas. The temperature of the sintering process is controlled by a program. / min The heating rate is raised from 100°C to 275°C, the temperature is kept at 275°C for 110 minutes, the temperature is raised from 275°C to 380°C, the heating rate is 3°C / min, and the temperature is kept for 90 minutes. After cooling, take it out and pull out the cylindrical support mold to obtain a cylindrical polytetrafluoroethylene membrane with a thickness of 171um, which can be cut to obtain a flat porous membrane. The membrane has a hydrophobic contact angle of 163°, a porosity...

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Abstract

The invention provides a preparation method of a polytetrafluoroethylene film. The preparation method comprises the steps of preparing fibers with a fiber forming carrier and sintering and is characterized by adopting multistep continuous sintering through program temperature control, and in flowing atmospheres, insulating at 90-120 DEG C for 30-120 minutes, increasing the temperature from 90-120 DEG C to 260-300 DEG C at a rate of 3-10 DEG C / min and insulating at 260-300 DEG C for 30-120 minutes; increasing the temperature from 260-300 DEG C to 370-390 DEG C at a rate of 2-8 DEG C / min and insulating at 370-390 DEG C for 5-120 minutes. The preparation method has the beneficial effects that the problem that fibers are easy to collapse during sintering of a polytetrafluoroethylene precursor film is well solved; a reticular film with bead-like superfine fibers is obtained; the fibers adhere to each other instead of being stacked out of order; the fibers have uniform morphologies, intact surfaces and greatly improved strength and tenacity and can bear a certain vacuum pressure.

Description

technical field [0001] The invention relates to a preparation method of a separation membrane material used in the separation field, in particular to a preparation method of a hydrophobic membrane material. technical background [0002] Hydrophobicity is an important property of polytetrafluoroethylene (PTFE) materials, and it is the main performance of PTFE porous membranes applied to membrane materials. Although polytetrafluoroethylene material has low surface energy, the water contact angle of smooth polytetrafluoroethylene plane is between 98° and 112°, and the hydrophobic performance is not good. [0003] At present, the biaxial stretching method is mostly used in the preparation of polytetrafluoroethylene porous membranes. When this method wants to obtain a film with a higher porosity, the film needs to be stretched at a large scale, the surface structure cannot be controlled, and the film thickness is only less than a dozen microns. Supporting materials are needed in...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D71/36B01D69/02B01D67/00
Inventor 姚永毅钟丕叶雷
Owner 四川百途环保材料科技有限公司
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