CN109940956B - Composite film with high interfacial strength and air permeability - Google Patents
Composite film with high interfacial strength and air permeability Download PDFInfo
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- CN109940956B CN109940956B CN201910119903.4A CN201910119903A CN109940956B CN 109940956 B CN109940956 B CN 109940956B CN 201910119903 A CN201910119903 A CN 201910119903A CN 109940956 B CN109940956 B CN 109940956B
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Abstract
The invention relates to the field of composite membranes and preparation thereof, in particular to a composite membrane with high interface strength and air permeability, which comprises a polytetrafluoroethylene membrane and an adhesive membrane arranged on the polytetrafluoroethylene membrane, wherein the compounding temperature of the adhesive membrane and the polytetrafluoroethylene membrane is 80-280 ℃, and the raw material of the adhesive membrane is made of a thermoplastic high polymer material; the intrinsic viscosity of the thermoplastic high polymer material is 0.5-1.2 dL/g. The composite membrane obtained by the invention has high interface strength and high air permeability, and the service life of the membrane is greatly prolonged.
Description
Technical Field
The invention relates to the field of composite membranes and preparation thereof, in particular to a composite membrane with high interface strength and air permeability.
Background
The polytetrafluoroethylene composite membrane is an asymmetric separation membrane, and is generally prepared by preparing a porous support membrane and then forming a very thin compact skin layer on the surface of the porous support membrane, wherein the two layers are usually different high polymers. The manufacturing technology of the composite membrane refers to a method for compounding a skin layer on the surface of a support membrane, and mainly comprises interface polymerization, monomer catalytic polymerization, solution casting, solution dip coating or spray coating, plasma polymerization, a water surface expansion method and the like. The above-mentioned method is difficult to prepare on a large scale because of its harsh preparation conditions. At present, a hot-melt bonding method is generally adopted to prepare the polytetrafluoroethylene composite membrane. Because of the low surface tension of polytetrafluoroethylene and the high surface tension of the supporting layer, the difficulty of forming the uniform and stable composite film by the polytetrafluoroethylene and the supporting layer is high, the peel strength of the composite film is usually low, and the service life is short. And adopt hot melt technology preparation polytetrafluoroethylene complex film, can form a layer of relatively compact cortex usually at the interface department of two kinds of membranes, this cortex has great influence to the gas flux of complex film, can make flux reduce usually, and filtration efficiency descends.
The prior art discloses various polytetrafluoroethylene composite membranes and methods for making the same. Patent application No. CN95190542 reports an asymmetric porous polytetrafluoroethylene membrane for a filter, wherein the asymmetric pore structure has a dense surface layer, so that the resistance is large when gas passes through the membrane. The polytetrafluoroethylene composite membrane prepared by the existing hot-melt bonding composite technology is difficult to tightly combine a supporting layer (a laminating membrane) and a polytetrafluoroethylene layer, so that the prepared composite membrane has low peel strength, is easy to separate and has short service life.
Disclosure of Invention
Aiming at the problems, the invention provides the composite membrane with high interface strength and air permeability, which is obtained by laminating a thermoplastic high polymer material and a polytetrafluoroethylene membrane.
In order to achieve the above purpose, the invention is realized by the following technical scheme: a composite membrane with high interface strength and air permeability comprises a polytetrafluoroethylene membrane and an adhesive membrane arranged on the polytetrafluoroethylene membrane, wherein the composite temperature of the adhesive membrane and the polytetrafluoroethylene membrane is 80-280 ℃, and the raw material of the adhesive membrane is a thermoplastic high polymer material; the intrinsic viscosity of the thermoplastic high polymer material is 0.5-1.2 dL/g.
According to the invention, the thermoplastic polymer material is partially filled into the gaps of the polytetrafluoroethylene membrane after the raw materials of the laminated membrane are melted, so that the composite membrane with high air permeability and high interface strength is obtained. The viscosity of the thermoplastic high polymer material is the key for forming the composite membrane, the high polymer material with the intrinsic viscosity of 0.5-1.2dL/g has good fluidity in the composite temperature range of the invention, and can be uniformly distributed in the gaps of the polytetrafluoroethylene membrane, the obtained composite membrane has excellent mechanical property, and when the viscosity of the thermoplastic high polymer material is higher, the fluidity is poorer, and the bonding time is shorter, the molten high polymer material has poorer micropore filling effect on the polytetrafluoroethylene membrane, so that the interface strength of the composite membrane is lower, and the aperture uniformity is poorer; the thermoplastic polymer material has low viscosity and good fluidity, and the micropore blockage of the polytetrafluoroethylene membrane can be caused when the residence time is long, so that the air permeability and the permeability are obviously reduced. Therefore, a thermoplastic high polymer material with appropriate viscosity is reasonably selected, the compounding temperature is reasonably controlled, the polytetrafluoroethylene film does not reach the melting point below 280 ℃, the thermoplastic high polymer material is already molten, and the polytetrafluoroethylene film can keep the mechanical property thereof while meeting the compounding condition, so that higher interface strength is obtained.
Preferably, the mass ratio of the polytetrafluoroethylene membrane to the thermoplastic high polymer material in unit area is (10-30): 1, the thermoplastic polymer material is used for strengthening the interfacial strength of polytetrafluoroethylene membrane and further promotes the filter effect in polytetrafluoroethylene membrane hole, and polytetrafluoroethylene membrane is the bed frame of complex film, further promotes the performance of membrane through compound thermoplastic polymer material, and thermoplastic polymer material should not be too much, causes the micropore jam easily, influences the gas permeability.
Preferably, the thickness of the polytetrafluoroethylene film is 100-2000 μm, the thickness of the adhesive film is 5-100 μm, and the thickness of the adhesive film is controlled to be thin, so that a more compact homogeneous film can be formed, the air permeability of the composite film is favorably improved, and the interface strength between the two films is favorably improved.
Preferably, when the polytetrafluoroethylene film and the laminating film are compounded, the raw material of the laminating film is laminated on the polytetrafluoroethylene film and then rolled by the hot roller to form the composite film, the advancing speed of the hot roller is 5-15m/min, the hot roller is used for melting, rolling and compounding, so that the composite film is rapidly molded, the film thickness on the surface of the composite film is more uniform, the condition that the difference of the thickness of the laminating film is too large is avoided, meanwhile, the advancing speed of the hot roller directly determines the retention time of the molten thermoplastic high polymer material on the surface of the polytetrafluoroethylene film, micropore blockage is easily caused at too low speed, the air permeability is influenced, and the interface strength is directly influenced due to insufficient quick compounding.
Further preferably, when the polytetrafluoroethylene film and the laminating film are compounded, a single-side hot roller is adopted for compounding, the hot roller is located on one side of the polytetrafluoroethylene film, the melting point of the thermoplastic high polymer material is lower, the hot roller is arranged on one side of the polytetrafluoroethylene film, and the laminating film adopts normal temperature.
Preferably, the thermoplastic polymer material is PU or PE or PPT or PVC, the composite performance with the polytetrafluoroethylene membrane is good, and the composite material has stronger interface strength when being compounded on the polytetrafluoroethylene membrane.
Preferably, the pore diameter of the polytetrafluoroethylene membrane is 0.5-5 μm, and the too large pore diameter of the polytetrafluoroethylene membrane easily causes the too deep filling of the thermoplastic high polymer material, and the uneven filling affects the stability of air permeability and mechanical property; too small a size easily causes the blockage of micropores of the composite membrane and loses the separation effect.
Preferably, the polytetrafluoroethylene membrane is a polytetrafluoroethylene bubble point membrane, the polytetrafluoroethylene bubble point membrane is formed through high-temperature melting and shaping, the performance is stable in a low-temperature interval, and the polytetrafluoroethylene bubble point membrane is used as a base layer of the composite membrane, so that the interface strength is high, and the service life is long.
Preferably, the air permeability of the composite membrane under the test pressure difference of 10kPa is 0.12-2.5L/cm2Min, interface strength 0.5-6N.
The invention has the following advantages:
(1) the composite membrane obtained by the invention has high interface strength and high air permeability, and the service life of the membrane is greatly prolonged.
(2) The invention has simple process, and the composite membrane can be quickly and effectively obtained by reasonably controlling the process parameters.
Detailed Description
The present embodiments are to be considered in all respects as illustrative and not restrictive. Any changes that may be made by one of ordinary skill in the art after reading the specification herein are, within the purview of the appended claims, to fall within the scope of the patent laws.
Example 1:
a composite membrane with high interface strength and air permeability is obtained by bonding a polytetrafluoroethylene bubble point membrane and a bonding membrane and rolling the membrane by a single-side hot roller at the temperature of 280 ℃ and the advancing speed of 15m/min, wherein the air permeability of the composite membrane under the test pressure difference of 10kPa is 0.12L/cm2Min, the interface strength is 6N, the adhesive film is made of PVC material, the intrinsic viscosity is 1.2dL/g, and polyThe mass ratio of the tetrafluoroethylene bubble point film to the PVC material is 30: 1, the pore diameter of the polytetrafluoroethylene bubble point membrane is 5 μm, the thickness is 2000 μm, and the thickness of the bonding membrane is 100 μm.
Example 2:
a composite film with high interfacial strength and air permeability is obtained by bonding a polytetrafluoroethylene film and a bonding film and rolling the bonded film by a single-side hot roller at the temperature of 150 ℃ and the advancing speed of 10m/min, wherein the air permeability of the composite film under the test pressure difference of 10kPa is 2L/cm2Min, the interface strength is 2.5N, the adhesive film is made of a PPT material, the intrinsic viscosity is 1dL/g, and the mass ratio of the polytetrafluoroethylene film to the PPT material is 20: 1, the pore diameter of the polytetrafluoroethylene membrane is 3 μm, the thickness is 500 μm, and the thickness of the adhesive membrane is 80 μm.
Example 3:
a composite film with high interfacial strength and air permeability is obtained by bonding a polytetrafluoroethylene film and a bonding film and rolling the film at a temperature of 80 ℃ and a running speed of 5m/min by a single-side hot roller, and the air permeability of the composite film is 2.5L/cm under a test pressure difference of 10kPa2Min, the interface strength is 2.8N, the adhesive film is made of a PE material, the intrinsic viscosity is 0.5dL/g, and the mass ratio of the polytetrafluoroethylene film to the PE material is 10: 1, the polytetrafluoroethylene film had a pore diameter of 0.1 μm and a thickness of 100 μm, and the thickness of the adhesive film was 5 μm.
Example 4:
a composite film with high interfacial strength and air permeability is obtained by bonding a polytetrafluoroethylene film and a bonding film and rolling the bonded film by a single-side hot roller at the temperature of 150 ℃ and the advancing speed of 10m/min, wherein the air permeability of the composite film under the test pressure difference of 10kPa is 1.8L/cm2Min, the interface strength is 3.8N, the adhesive film is made of a PU material, the intrinsic viscosity is 0.8dL/g, and the mass ratio of the polytetrafluoroethylene film to the PU material is 15: 1, the pore diameter of the polytetrafluoroethylene membrane is 1 μm, the thickness is 800 μm, and the thickness of the adhesive membrane is 40 μm.
Example 5:
a composite membrane with high interface strength and air permeability is prepared through sticking teflon membrane to the sticking membrane, and moving at 200 deg.C and 8m/minObtained after rolling by a hot roller, and the air permeability of the composite film is 2L/cm under the test pressure difference of 10kPa2Min, the interface strength is 4.3N, the adhesive film is made of a PE material, the intrinsic viscosity is 1dL/g, and the mass ratio of the polytetrafluoroethylene film to the PE material is 15: 1, the pore diameter of the polytetrafluoroethylene film was 2 μm, the thickness was 100 μm, and the thickness of the adhesive film was 100 μm.
Comparative example 1:
otherwise, the same as example 1, except that the temperature of the composite film was changed to 300 ℃ to obtain a composite film having an air permeability of 0.06L/cm under a test differential pressure of 10kPa2Min, interface strength 8N.
Comparative example 2:
otherwise, the same as example 2, except that the running speed of the hot roll was changed to 20m/min, the air permeability of the obtained composite film under a test differential pressure of 10kPa was 1.3L/cm2Min, interface strength 0.3N.
Comparative example 3:
otherwise, the same as example 3, except that PTFE having an intrinsic viscosity of 1.5dL/g was used as a raw material for the adhesive film, and the air permeability of the resulting composite film was 0.09L/cm under a test differential pressure of 10kPa2Min, interface strength 5N.
Comparative example 4:
otherwise, the same as example 4 except that the thickness of the polytetrafluoroethylene film was 50 μm, the thickness of the adhesive film was controlled to 500. mu.m, and the air permeability of the resulting composite film was 0.9L/cm under a test differential pressure of 10kPa2Min, interface strength 3.2N.
Comparative example 5:
otherwise the same as example 5 except that the pore diameter of the polytetrafluoroethylene film was 8 μm, the air permeability of the resulting composite film at a test differential pressure of 10kPa was 1.2L/cm2Min, interface strength 5N.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (5)
1. A composite film of high interfacial strength and breathability characterized by: the adhesive film comprises a polytetrafluoroethylene film and an adhesive film arranged on the polytetrafluoroethylene film, wherein the compounding temperature of the adhesive film and the polytetrafluoroethylene film is 80-280 ℃, and the raw material of the adhesive film is a thermoplastic high polymer material; the intrinsic viscosity of the thermoplastic high polymer material is 0.5-1.2 dL/g; when the polytetrafluoroethylene film and the laminating film are compounded, the raw material of the laminating film is laminated on the polytetrafluoroethylene film and then rolled by a hot roller to form a composite film, wherein the advancing speed of the hot roller is 5-15 m/min; the thickness of the polytetrafluoroethylene film is 100-2000 mu m, and the thickness of the adhesive film is 5-100 mu m; the thermoplastic polymer material is PU or PE or PVC; the pore diameter of the polytetrafluoroethylene membrane is 0.1-5 mu m.
2. A high interfacial strength and gas permeability composite membrane according to claim 1, wherein: in unit area, the mass ratio of the polytetrafluoroethylene membrane to the thermoplastic high polymer material is (10-30): 1.
3. a high interfacial strength and gas permeability composite membrane according to claim 1, wherein: when the polytetrafluoroethylene membrane and the laminating membrane are compounded, a single-side hot roller is adopted for compounding, and the hot roller is positioned on one side of the polytetrafluoroethylene membrane.
4. A high interfacial strength and gas permeability composite membrane according to claim 1, wherein: the polytetrafluoroethylene membrane is a polytetrafluoroethylene bubble point membrane.
5. A high interfacial strength and gas permeability composite membrane according to claim 1, wherein: the air permeability of the composite membrane under the test differential pressure of 10kPa is 0.12-2.5L/cm2Min, interface strength 0.5-6N.
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| CN113334670A (en) * | 2021-06-04 | 2021-09-03 | 浙江格尔泰斯环保特材科技股份有限公司 | PTFE composite material film and preparation method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102068924A (en) * | 2010-12-22 | 2011-05-25 | 中国科学院长春应用化学研究所 | Polytetrafluoroethylene composite membrane and preparation method thereof |
| CN103862774A (en) * | 2014-03-25 | 2014-06-18 | 湖州森诺氟材料科技有限公司 | Double-component windproof ventilating film |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102068924A (en) * | 2010-12-22 | 2011-05-25 | 中国科学院长春应用化学研究所 | Polytetrafluoroethylene composite membrane and preparation method thereof |
| CN103862774A (en) * | 2014-03-25 | 2014-06-18 | 湖州森诺氟材料科技有限公司 | Double-component windproof ventilating film |
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Denomination of invention: Composite film with high interfacial strength and air permeability Effective date of registration: 20210825 Granted publication date: 20210611 Pledgee: South Taihu New Area sub branch of Huzhou Wuxing Rural Commercial Bank Co.,Ltd. Pledgor: ZHEJIANG KERTICE HI-TECH FLUOR-MATERIAL Co.,Ltd. Registration number: Y2021330001233 |
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Date of cancellation: 20230103 Granted publication date: 20210611 Pledgee: South Taihu New Area sub branch of Huzhou Wuxing Rural Commercial Bank Co.,Ltd. Pledgor: ZHEJIANG KERTICE HI-TECH FLUOR-MATERIAL CO.,LTD. Registration number: Y2021330001233 |
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