CN109224886B - Polytetrafluoroethylene tubular microporous membrane and preparation method thereof - Google Patents

Polytetrafluoroethylene tubular microporous membrane and preparation method thereof Download PDF

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Publication number
CN109224886B
CN109224886B CN201811128710.7A CN201811128710A CN109224886B CN 109224886 B CN109224886 B CN 109224886B CN 201811128710 A CN201811128710 A CN 201811128710A CN 109224886 B CN109224886 B CN 109224886B
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microporous membrane
polytetrafluoroethylene
deoiling
temperature
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CN109224886A (en
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黎鹏
曹亚丽
王霞
臧正保
王磊
李振
周超
吴良
杨力凯
赵雨
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Huashi Design Group Environmental Technology Co ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/30—Polyalkenyl halides
    • B01D71/32—Polyalkenyl halides containing fluorine atoms
    • B01D71/36—Polytetrafluoroethene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0002—Organic membrane manufacture
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0002—Organic membrane manufacture
    • B01D67/0004—Organic membrane manufacture by agglomeration of particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/04—Tubular membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/04—Tubular membranes
    • B01D69/043—Tubular membranes characterised by the tube diameter

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

The invention disclosesA tubular microporous teflon film is prepared through mixing dispersed teflon resin with solvent oil, ageing, blanking, extruding, deoiling, stretching and sinter shaping, and features hollow tubular structure with internal diameter of 30-200mm, wall thickness less than 2% of internal diameter, and multiple micropores distributed on its wall, pore diameter of 0.3-1.0 microns, porosity greater than or equal to 80%, and tensile strength 120N/mm2The above properties and the like; the lower wall thickness is beneficial to improving the membrane separation performance; the inner diameter is far larger than that of the hollow fiber membrane, and the microporous membrane has higher porosity, greatly expands the application range of the microporous membrane, and effectively has the advantages of both the tube and the filtering membrane; can be widely applied to the fields of sewage filtration, oil-water separation, membrane distillation and the like; the preparation method has the advantages of simple process, no environmental pollution, easy operation, suitability for industrial production, strong practicability and wide applicability.

Description

Polytetrafluoroethylene tubular microporous membrane and preparation method thereof
Technical Field
The invention relates to a polytetrafluoroethylene tubular microporous membrane, in particular to a polytetrafluoroethylene tubular microporous membrane and a preparation method thereof.
Background
Polytetrafluoroethylene (PTFE) is a special engineering plastic with excellent comprehensive performance and has the reputation of plastic king. The PTFE microporous membrane has the advantages of acid and alkali resistance, chemical corrosion resistance, radiation resistance, excellent biocompatibility and the like, can be used for a long time at the temperature of-200-260 ℃, and is an ideal membrane separation material in the industries of environmental protection, chemical engineering, biological medicine and the like.
At present, commercial PTFE microporous membranes at home and abroad are mainly flat membranes, and production and manufacturing of PTFE hollow fiber membranes are mastered by a few companies, such as POREFLON of Japanese Sumitomo, ZEFLOUR of GORE in America and the like.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a polytetrafluoroethylene tubular microporous membrane with excellent performances of both a hollow fiber membrane and a flat membrane and a preparation method thereof.
In order to achieve the above object, the present invention adopts the following technical solutions:
a polytetrafluoroethylene tubular microporous membrane is of a hollow tubular structure, the inner diameter is 30-200mm, the wall thickness is less than 2% of the inner diameter, a plurality of micropores are distributed on the wall of the tubular microporous membrane, the aperture of the micropores is 0.3-1.0 mu m, the porosity is more than or equal to 80%, and the tensile strength is 120N/mm2The above.
The polytetrafluoroethylene tubular microporous membrane comprises the following components in parts by mass:
70-80% of dispersion type polytetrafluoroethylene resin and 20-30% of solvent oil.
Further, the solvent oil includes at least one of kerosene, white oil, toluene, alcohol, and acetone.
Furthermore, the crystallinity of the dispersion type polytetrafluoroethylene resin is 98-99.9%, and the molecular weight is 200-1000 ten thousand; such as commercial products, Dajin F104, F106, Suwei 261, Juhua 188, etc.
The preparation method of the polytetrafluoroethylene tubular microporous membrane comprises the following steps:
s1, mixing the dispersed polytetrafluoroethylene resin sieved by the screen mesh with solvent oil according to a certain mass fraction, and sealing and aging at a certain temperature;
s2, pouring the aged mixture into a cylindrical green press with a core rod, and pressing into a hollow cylindrical green body;
s3, putting the cylindrical blank into an extrusion cylinder, and extruding the cylindrical blank by a plunger to form tubular primary raw material; in the pushing process, PTFE dispersion resin is directionally arranged to form a regular fiber structure;
and S4, sequentially deoiling, stretching, sintering and shaping the nascent PTFE tube on the screw rod by utilizing the pushing action of the plunger, the conveying action of the rotating screw rod at the center of the neck mold and the traction action of winding, and winding to obtain the polytetrafluoroethylene tube type microporous membrane.
The screw comprises a deoiling section, a stretching section and a sintering section;
the pitch of the sintering section is not less than that of the deoiling section, the stretching section is connected with the deoiling section and the sintering section, and the pitch is gradually changed.
Preferably, the sintering section and the deoiling section are designed in a constant pitch mode, and each section is a continuous channel.
Furthermore, the length-diameter ratio of the screw is 5-40, the pitch of the deoiling section is 0.25-0.5mm, and the pitch of the sintering section is 0.5-25 mm.
The mesh size of the screen mesh in the step S1 is 8-10 meshes, the sealing temperature is 40-60 ℃, and the aging time is 6-24 h.
The green compact in the step S2 is at a temperature of 40-50 ℃, a pressure of 4-6MPa and a dwell time of 5-15 min; the extrusion temperature of the ram extruder in step S3 was 40 to 60 ℃.
The rotation speed of the screw in the S4 is 2-30rpm, the deoiling temperature is 220-.
The invention has the advantages that:
the polytetrafluoroethylene tubular microporous membrane provided by the invention can be widely applied to the fields of sewage filtration, oil-water separation, membrane distillation and the like; the lower wall thickness is beneficial to improving the membrane separation performance; the inner diameter of the hollow fiber membrane is far larger than that of the hollow fiber membrane, and meanwhile, the stretching of the primary PTFE tube is realized by utilizing the change of the thread pitch, which is different from the axial traction stretching.
The invention provides a preparation method of a polytetrafluoroethylene tubular microporous membrane, which integrally completes the preparation of the polytetrafluoroethylene tubular microporous membrane on a screw; deoiling the primary PTFE tube by conveying with a small pitch at the front end of the screw, gradually stretching the primary PTFE tube by gradually changing the pitch at the middle section of the screw, stabilizing the stretched tube shape by the pitch at the tail end of the screw at equal intervals, sintering the tube at the section at high temperature, and fixing and molding; the preparation method has the advantages of simple process, no environmental pollution, easy operation, suitability for industrial production, strong practicability and wide applicability.
Detailed Description
The present invention will be described in detail with reference to the following embodiments.
The raw materials and instruments used in the invention are all commercially available.
And (3) detecting the tensile strength: CMT-5254 electronic universal tester, Shenzhen New Miss group.
Example 1
1) Uniformly mixing the dispersed polytetrafluoroethylene resin F106 sieved by an 8-mesh screen and kerosene according to the mass ratio of 76:24, and then sealing and aging at 40 ℃ for 12 hours;
2) pouring the aged mixture into a 50 ℃ cylindrical green press, pressing under the pressure of 5MPa to prepare a hollow cylindrical green body, and keeping the pressure for 8min and then taking out;
3) putting the cylindrical blank into a 50 ℃ extrusion cylinder, and extruding by a plunger to form tubular primary raw material with the inner diameter of 90 mm;
4) selecting a screw rod with the outer diameter of 90mm, the length-diameter ratio of 15, the screw pitch of a deoiling section of 0.4mm and the length of 250 mm; the pitch of the front section of the stretching section is 0.4mm, the pitch of the tail end of the stretching section is 2.0mm, and the length of the stretching section is 950 mm; the pitch of the sintering section is 2.0mm, and the length is 150 mm;
5) the rotating speed of the screw is controlled at 10 rpm;
6) the temperature of the deoiling section is 250 ℃, the temperature of the stretching section is 280 ℃ and the temperature of the sintering section is 390 ℃;
7) the nascent PTFE tube is sequentially deoiled, stretched, sintered, shaped and rolled to obtain the polytetrafluoroethylene tubular microporous membrane, and various performance test results are as follows: an inner diameter of 92mm, a wall thickness of 1.1mm, an average pore diameter of 0.92 μm, a porosity of 89%, and a tensile strength of 132N/mm2。
Example 2
1) Uniformly mixing the dispersed polytetrafluoroethylene resin F104 sieved by a 10-mesh screen and white oil according to a mass ratio of 70:30, and sealing and aging at 40 ℃ for 18 hours;
2) pouring the aged mixture into a cylindrical briquetting machine at 40 ℃, pressing under the pressure of 4MPa to prepare a hollow cylindrical green body, maintaining the pressure for 15min, and taking out;
3) putting the cylindrical blank into an extrusion cylinder at 40 ℃, and extruding by a plunger to form tubular primary raw material with the inner diameter of 200 mm;
4) selecting the external diameter of 200mm, the length-diameter ratio of 7, the screw pitch of a deoiling section of 1.0mm and the length of 250 mm; the pitch of the front section of the stretching section is 1.0mm, the pitch of the tail end of the stretching section is 3.0mm, and the length of the stretching section is 950 mm; the pitch of the sintering section is 3.0mm, and the length is 200 mm;
5) the rotating speed of the screw is controlled at 30 rpm;
6) the temperature of the deoiling section is 260 ℃, the temperature of the stretching section is 300 ℃, and the temperature of the sintering section is 360 ℃;
7) the nascent PTFE tube is sequentially deoiled, stretched, sintered, shaped and rolled to obtain the polytetrafluoroethylene tubular microporous membrane, and various performance test results are as follows: 200mm of inner diameter, 4.3mm of wall thickness, 0.44 μm of average pore diameter, 82% of porosity and 171N/mm of tensile strength2。
Example 3
1) Uniformly mixing the dispersed polytetrafluoroethylene resin 261 sieved by an 8-mesh screen and toluene according to the mass ratio of 72:28, and then sealing and aging at 50 ℃ for 24 hours;
2) pouring the aged mixture into a 50 ℃ cylindrical green press, pressing under the pressure of 6MPa to prepare a hollow cylindrical green body, maintaining the pressure for 15min, and taking out;
3) putting the cylindrical blank into an extrusion cylinder at 60 ℃, and extruding by a plunger to form tubular primary raw material with the inner diameter of 30 mm;
4) selecting the external diameter of 30mm, the length-diameter ratio of 40, the screw pitch of a deoiling section of 0.25mm and the length of 200 mm; the pitch of the front section of the stretching section is 0.25mm, the pitch of the tail end of the stretching section is 1.0mm, and the length of the stretching section is 900 mm; the pitch of the sintering section is 1.0mm, and the length is 100 mm;
5) the rotating speed of the screw is controlled at 2 rpm;
6) the temperature of the deoiling section is 220 ℃, the temperature of the stretching section is 280 ℃, and the temperature of the sintering section is 360 ℃;
7) the nascent PTFE tube is sequentially deoiled, stretched, sintered, shaped and rolled to obtain the polytetrafluoroethylene tubular microporous membrane, and various performance test results are as follows: inner diameter of 32mm, wall thickness of 0.6mm, average pore diameter of 0.32 μm, porosity of 80%, and tensile strength of 121N/mm2。
Example 4
1) Uniformly mixing the dispersed polytetrafluoroethylene resin 188 sieved by a 10-mesh sieve and alcohol according to the mass ratio of 80:20, and then sealing and aging at 40 ℃ for 6 hours;
2) pouring the aged mixture into a cylindrical briquetting machine at 40 ℃, pressing under 6MPa to prepare a hollow cylindrical green body, maintaining the pressure for 12min, and taking out;
3) putting the cylindrical blank into an extrusion cylinder at 40 ℃, and extruding by a plunger to form tubular primary raw material with the inner diameter of 65 mm;
4) selecting 65mm of outer diameter, 20 of length-diameter ratio, 0.5mm of screw pitch of a deoiling section and 250mm of length; the pitch of the front section of the stretching section is 0.5mm, the pitch of the tail end of the stretching section is 1.5mm, and the length of the stretching section is 950 mm; the pitch of the sintering section is 1.5mm, and the length is 100 mm;
5) the rotating speed of the screw is controlled at 5 rpm;
6) the temperature of the deoiling section is 250 ℃, the temperature of the stretching section is 320 ℃, and the temperature of the sintering section is 410 ℃;
7) nascent PThe TFE tube is deoiled, stretched, sintered, shaped and rolled in sequence to obtain the polytetrafluoroethylene tube type microporous membrane, and various performance test results are as follows: an inner diameter of 65mm, a wall thickness of 2.1mm, an average pore diameter of 0.83 μm, a porosity of 89%, and a tensile strength of 130N/mm2。
Example 5
1) Uniformly mixing the dispersed polytetrafluoroethylene resin F106 sieved by an 8-mesh screen and kerosene according to the mass ratio of 80:20, and then sealing and aging at 40 ℃ for 12 hours;
2) pouring the aged mixture into a 50 ℃ cylindrical green press, pressing under the pressure of 6MPa to prepare a hollow cylindrical green body, maintaining the pressure for 5min, and taking out;
3) putting the cylindrical blank into an extrusion cylinder at 50 ℃, and extruding by a plunger to form tubular primary raw material with the inner diameter of 150 mm;
4) selecting 150mm of outer diameter, 9 of length-diameter ratio, 1.0mm of screw pitch of a deoiling section and 250mm of length; the pitch of the front section of the stretching section is 1.0mm, the pitch of the tail end of the stretching section is 2.0mm, and the length of the stretching section is 950 mm; the pitch of the sintering section is 2.0mm, and the length is 150 mm;
5) the rotating speed of the screw is controlled at 10 rpm;
6) the temperature of the deoiling section is 260 ℃, the temperature of the stretching section is 360 ℃ and the temperature of the sintering section is 420 ℃;
7) the nascent PTFE tube is sequentially deoiled, stretched, sintered, shaped and rolled to obtain the polytetrafluoroethylene tubular microporous membrane, and various performance test results are as follows: 153mm inner diameter, 1.7mm wall thickness, 0.62 μm average pore diameter, 83% porosity and 156N/mm tensile strength2。
The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It should be understood by those skilled in the art that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by using equivalent alternatives or equivalent variations fall within the scope of the present invention.

Claims (10)

1. The preparation method of the polytetrafluoroethylene tubular microporous membrane is characterized by comprising the following steps:
s1, mixing the dispersed polytetrafluoroethylene resin sieved by the screen mesh with solvent oil according to a certain mass fraction, and sealing and aging at a certain temperature;
s2, pouring the aged mixture into a cylindrical green press with a core rod, and pressing into a hollow cylindrical green body;
s3, putting the cylindrical blank into an extrusion cylinder, and extruding the cylindrical blank by a plunger to form tubular primary raw material;
and S4, sequentially deoiling, stretching, sintering and shaping the nascent PTFE tube on the screw rod by utilizing the pushing action of the plunger, the conveying action of the rotating screw rod at the center of the neck mold and the traction action of winding, and winding to obtain the polytetrafluoroethylene tube type microporous membrane.
2. The method for preparing a polytetrafluoroethylene tubular microporous membrane according to claim 1, wherein the screw comprises a deoiling section, a stretching section and a sintering section;
the pitch of the sintering section is not less than that of the deoiling section, the stretching section is connected with the deoiling section and the sintering section, and the pitch is gradually changed.
3. The method of claim 2, wherein the screw has a length-diameter ratio of 5-40, a pitch of the deoiling section of 0.25-0.5mm, and a pitch of the sintering section of 0.5-25 mm.
4. The method as claimed in claim 1, wherein the mesh size of the screen in step S1 is 8-10 mesh, the sealing temperature is 40-60 ℃, and the aging time is 6-24 h.
5. The method of claim 1, wherein the green compact in step S2 has a temperature of 40-50 ℃, a pressure of 4-6MPa, and a dwell time of 5-15 min; the extrusion temperature of the ram extruder in step S3 was 40 to 60 ℃.
6. The method as claimed in claim 1, wherein the rotation speed of the screw in S4 is 2-30rpm, the deoiling temperature is 220-260 ℃, the stretching temperature is 260-360 ℃, and the sintering temperature is 360-420 ℃.
7. The method for preparing a polytetrafluoroethylene tubular microporous membrane according to claim 1, wherein the polytetrafluoroethylene tubular microporous membrane is of a hollow tubular structure, the inner diameter is 30-200mm, the wall thickness is less than 2% of the inner diameter, a plurality of micropores are distributed on the wall, the pore diameter of the micropores is 0.3-1.0 μm, the porosity is greater than or equal to 80%, and the tensile strength is 120N/mm2The above.
8. The preparation method of the polytetrafluoroethylene tubular microporous membrane according to claim 1, wherein the polytetrafluoroethylene tubular microporous membrane comprises the following components in parts by mass:
70-80% of dispersion type polytetrafluoroethylene resin and 20-30% of solvent oil.
9. The method of claim 8, wherein the solvent oil comprises at least one of kerosene, white oil, toluene, alcohol, and acetone.
10. The method of claim 8, wherein the dispersed polytetrafluoroethylene resin has a crystallinity of 98 to 99.9% and a molecular weight of 200 to 1000 ten thousand.
CN201811128710.7A 2018-09-27 2018-09-27 Polytetrafluoroethylene tubular microporous membrane and preparation method thereof Active CN109224886B (en)

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KR101599111B1 (en) * 2013-12-31 2016-03-02 도레이케미칼 주식회사 PTFE hollow fiber membrane and production method thereof
CN104815564B (en) * 2015-04-20 2018-09-04 刘显志 It is a kind of can virus-isolating or bacterium ePTFE membrane and preparation method thereof
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