Polytetrafluoroethylene hollow fiber micro-porous film and preparation method thereof

A polytetrafluoroethylene, porous membrane technology, used in chemical instruments and methods, membrane technology, semi-permeable membrane separation, etc. The effect of high efficiency, high mechanical strength and no pollution to the environment

Active Publication Date: 2013-03-13
TIANJIN SEA WATER DESALINATION & COMPLEX UTILIZATION INST STATE OCEANOGRAPHI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] Aiming at the technical defects existing in the prior art, the present invention provides a method for preparing a polytetrafluoroethylene hollow fiber porous membrane with simple process, no pollution to the environment, easy operation and no need for follow-up treatment. The unsintered polytetrafluoroethylene (PTFE) hollow fiber (hereinafter referred to as nascent PTFE hollow fiber) is relatively fragile, and it is easy to break under the action of external force, resulting in the difficulty of stretching and forming pores, and the technical problems that the pore size and porosity are difficult to control.

Method used

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  • Polytetrafluoroethylene hollow fiber micro-porous film and preparation method thereof
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  • Polytetrafluoroethylene hollow fiber micro-porous film and preparation method thereof

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preparation example Construction

[0040] The preparation steps of the nascent PTFE hollow fiber include mixing PTFE resin and auxiliary oil, preforming compacts and pushing molding to prepare the nascent PTFE hollow fiber.

[0041] Select PTFE dispersion resin with a molecular weight of 1 million to 5 million, a compression ratio of 300 times to 3000 times, and a crystallinity greater than 98%; the PTFE dispersion resin can be either a PTFE resin or a blend of two resins in proportion; when a When a kind of PTFE resin is raw material, preferred molecular weight 2,000,000-4,000,000. This is because, when the molecular weight is less than 2 million, stretching is easy to form holes, but the primary PTFE hollow fiber is easy to break when stretching, and the size of the micropores formed during the stretching process is not easy to control; when the molecular weight is greater than 4 million, it is difficult to stretch to form holes. .

[0042] Auxiliary oil can adopt the following types among the present invent...

Embodiment 1

[0063] 1000g PTFE dispersion resin (Daikin Company. Polyflon, F-205) was mixed with 200g additive oil (Mobil Company Isopar G). Place the mixture at 30°C for about 24 hours to allow the additive oil to completely penetrate into the PTFE resin; then, fill the mixture into a steel cylinder with a diameter of 50mm and a length of 600mm, and place a core rod with a diameter of 12mm in the center of the steel cylinder. After the cylinder is filled, it is pre-pressed; further, the preform is transferred and placed in the extruder barrel of the push molding equipment, kept at 40°C for 10 minutes, and pushed at a constant speed at 5MPa to obtain an outer diameter of 5mm and a wall thickness of 1.2 mm PTFE blank tube, that is, primary PTFE hollow fiber.

[0064] The primary PTFE hollow fiber was heat-treated at 300°C for 120 minutes; six samples of PTFE hollow fiber 1#, 2#, 3#, 4#, 5# and 6# after heat treatment were stretched to cause holes and sintered to form PTFE hollow fibers. Fi...

Embodiment 2

[0091] 1000g of PTFE dispersion resin is mixed with 200g of auxiliary oil, and the mixture is made into nascent PTFE hollow fiber according to the method in Example 1, with an outer diameter of 5mm and a wall thickness of 1.2mm.

[0092] The primary PTFE hollow fiber is heat-treated at 350°C for 1min; the heat-treated PTFE hollow fiber is stretched 3 times in the axial direction at 200°C, and the stretching rate is 3000mm / min; under tension, the obtained stretched fiber is sintered at 340°C furnace, setting for 2min, and the sample was cooled naturally to obtain a PTFE hollow fiber membrane. Microporous structure on the inner surface of PTFE hollow fiber membrane see Figure 7c , is a sponge-like microporous structure. The outer diameter of the membrane is 4.5mm, the wall thickness is 1.0mm, the average pore diameter is 0.9μm, the porosity is 62%, and the tensile strength at break is 45MPa.

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Abstract

The invention discloses a polytetrafluoroethylene hollow fiber micro-porous film and a preparation method thereof. The preparation method comprises the preparation steps of: preparing a primary PTFE (Polytetrafluoroethylene) hollow fiber, carrying out heat treatment, stretching to form a hole, sintering and sizing. According to the polytetrafluoroethylene hollow fiber micro-porous film and the preparation method thereof, a pushing-pressing molding PTFE fiber pipe preparation technology is organically combined with a stretching-method micro-porous film preparation technology; an un-sintered PTFE fiber pipe prepared by a pushing-pressing molding method is a primary hollow fiber and the film is prepared by a stretching method, so as to realize the effective control of a pore diameter structure, and a PTFE hollow fiber film with needed hole diameter, higher porosity and large mechanical strength is obtained; furthermore, the polytetrafluoroethylene hollow fiber micro-porous film has a simple process, has no pollution to an environment, is easy to operate and does not need subsequent treatment; and therefore, the technical problems that the primary PTFE hollow fiber is more fragile and is easy to damage under the effect of external force, a process of stretching to form the hole is difficult, the hole diameter and the porosity are difficult to control are solved.

Description

technical field [0001] The invention relates to the technical field of membrane preparation, in particular to a polytetrafluoroethylene hollow fiber porous membrane and a preparation method thereof. Background technique [0002] The English abbreviation of polytetrafluoroethylene is PTFE. PTFE porous membrane has the advantages of acid and alkali resistance, chemical corrosion resistance, radiation resistance and excellent biocompatibility. It can be used for a long time at -200°C-260°C. , biomedicine and other industries ideal membrane separation materials. Making it into a hollow fiber structure can significantly increase the packing density of its components, give full play to the advantages of efficient separation and space saving of membrane products, and at the same time help to upgrade the existing membrane separation technology, which is convenient for engineering application and promotion. [0003] At present, the PTFE porous membranes that have been commercialized...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/36B01D69/08B01D67/00
Inventor 刘国昌吕经烈关毅鹏李浩李晓明
Owner TIANJIN SEA WATER DESALINATION & COMPLEX UTILIZATION INST STATE OCEANOGRAPHI
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