Ultrahigh molecular weight polyethylene hollow fiber composite membrane as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of membrane separation, and relates to an ultra-high molecular weight polyethylene hollow fiber composite membrane and a preparation method and application thereof.The ultra-high molecular weight polyethylene hollow fiber composite membrane is of an inner and outer composite multi-layer structure and comprises a supporting sleeve and a filtering layer set wound around the outer surface of the supporting sleeve; wherein the filtering layer group is made of ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene is of a two-way stretching net-shaped porous structure; the preparation method of the ultra-high molecular weight polyethylene hollow fiber composite membrane comprises the steps of slitting, winding and sintering which are carried out in sequence. According to the preparation method, the excellent characteristics of the ultra-high molecular weight polyethylene are utilized, a traditional spinning process is not needed, the hollow fiber membrane with high strength, high filtering precision and high pollution resistance is finally prepared through slitting, winding and sintering which are sequentially carried out, and the application limitation caused by performance defects of a traditional membrane is solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of membrane separation technology, and relates to a polyethylene hollow fiber composite membrane, in particular to an ultrahigh molecular weight polyethylene hollow fiber composite membrane and a preparation method and application thereof. BACKGROUND

[0002] As a green separation technology with great development potential in the 21st century, membrane separation technology plays an irreplaceable role in water resource purification, industrial fluid separation, and biological and pharmaceutical purification due to its low energy consumption, no secondary pollution, and simple operation. Among them, hollow fiber membranes, with high unit volume packing density, easy to regenerate, and easy to modularize, have become one of the most widely used forms in membrane separation technology, and their performance directly determines the efficiency, cost and stability of the separation process.

[0003] However, the existing preparation technology and material selection of hollow fiber membranes still have significant limitations. At present, the mainstream hollow fiber membranes in the industry are mostly prepared by wet spinning or thermally induced phase separation, and the materials used are mainly high molecular polymers such as polyvinylidene fluoride (PVDF), polysulfone (PSF), polyether sulfone (PES), polyacrylonitrile (PAN), and polyvinyl chloride (PVC). These materials can meet the basic filtration requirements in specific scenarios, but their performance shortcomings seriously restrict the overall performance of the membranes: for example, polyvinylidene fluoride membranes have a narrow pH range (usually only 2-11), are prone to swelling or degradation in strong alkaline environments, and have low impact strength, which can easily break down during long-term use; although polysulfone and polyether sulfone membranes have good mechanical properties, they have poor chlorine resistance and are easily oxidized and aged in chlorine-containing water bodies (such as the disinfection stage of municipal sewage treatment), which can cause the membrane pore size to increase and the filtration precision to decrease; polyacrylonitrile membranes are prone to degradation due to changes in environmental humidity and temperature, which can increase the brittleness of the membrane and shorten its service life; and polyvinyl chloride membranes have low cost, but are highly brittle and have poor impact resistance, which can easily cause them to break during high-pressure filtration or backwashing.

[0004] As can be seen, the defects of the above-mentioned materials directly lead to problems such as unstable filtration efficiency, weak anti-pollution ability, short service life, and high maintenance cost of the existing hollow fiber membranes in actual applications. For example, in industrial wastewater treatment, traditional membranes are prone to chemical corrosion or pollution and clogging due to the presence of acids, bases, oxidizing agents, or high concentrations of pollutants in the wastewater, which not only increases the operating cost but also reduces the continuity of the treatment system; in seawater desalination pretreatment, traditional membranes are difficult to withstand residual chlorine during the seawater disinfection process due to their poor chlorine resistance, which leads to rapid degradation of the membrane performance. These problems limit the applicability of existing hollow fiber membranes in complex working conditions and cannot meet the growing demand for high-difficulty separation.

[0005] In addition, as a high-performance engineering plastic, ultra-high molecular weight polyethylene (UHMWPE) has excellent wear resistance, impact resistance, chemical corrosion resistance and self-lubricity, but its high crystallinity and high melt viscosity make it difficult to be prepared into hollow fiber membranes by traditional spinning process, resulting in that the application of this high-performance material in the field of membrane separation has been in a blank state for a long time.

[0006] Therefore, how to break through the performance bottleneck of traditional materials, develop a kind of hollow fiber membrane with simple process, controllable cost, high strength, high filtration precision and high pollution resistance by using the excellent properties of ultra-high molecular weight polyethylene has become a problem to be solved by the technical personnel in the field. SUMMARY

[0007] In view of the deficiencies of the prior art, the purpose of the present application is to provide an ultra-high molecular weight polyethylene hollow fiber composite membrane and its preparation method and application, which utilizes the excellent properties of ultra-high molecular weight polyethylene to prepare a hollow fiber membrane with high strength, high filtration precision and high pollution resistance, solving the application limitation of traditional membranes caused by performance defects.

[0008] To achieve the purpose of the present application, the following technical solutions are adopted:

[0009] In a first aspect, the present application provides an ultra-high molecular weight polyethylene hollow fiber composite membrane, which has an inner-outer composite multi-skin structure and comprises a support sleeve and a filter layer group wound on the outer surface of the support sleeve.

[0010] The material of the filter layer group is ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene has a bidirectional stretching net-like porous structure; the preparation method of the ultra-high molecular weight polyethylene hollow fiber composite membrane comprises the steps of slitting, winding and sintering in sequence.

[0011] The hollow fiber composite membrane provided by the present application has an inner-outer composite multi-skin structure, organically combining the supporting effect of the support sleeve and the filtering effect of the filter layer group, and taking into account the filtration performance and structural stability of the composite membrane. In particular, the filter layer group relies on the properties of ultra-high molecular weight polyethylene and has high strength and excellent wear resistance, chemical resistance and pollution resistance, which can meet the precise filtration needs of different scenes and effectively solve the application limitation of traditional membranes caused by performance defects.

[0012] In addition, the present application adopts a three-step method of slitting-winding-sintering to prepare the ultra-high molecular weight polyethylene hollow fiber composite membrane, which does not require traditional spinning process and can realize continuous production. Compared with traditional wet and hot process, the above-mentioned three-step method eliminates the complex solvent treatment step, has high raw material utilization rate and greatly reduces the production cost, and is suitable for industrialized popularization and application.

[0013] Preferably, the support sleeve is an organic fiber woven sleeve, and the material includes any one or a combination of at least two of polyester, aramid, ultra-high molecular weight polyethylene, polypropylene, acrylic, nylon, or polyphenylene sulfide.

[0014] Preferably, the number of layers of the filter layer group is ≤8 layers.

[0015] Preferably, the average molecular weight of the ultra-high molecular weight polyethylene is ≥10 million.

[0016] Preferably, the nominal pore size of the ultra-high molecular weight polyethylene hollow fiber composite membrane is 0.005-2.5 μm.

[0017] Preferably, the pure water flux of the ultra-high molecular weight polyethylene hollow fiber composite membrane at 25℃ is 5-5000 L / m 2 ·h·bar.

[0018] In a second aspect, the present application provides a preparation method of the ultra-high molecular weight polyethylene hollow fiber composite membrane according to the first aspect, and the preparation method comprises the following steps:

[0019] (1) slitting: slitting a flat plate ultra-high molecular weight polyethylene porous membrane into a narrow strip;

[0020] (2) winding: winding the narrow strip on the outer surface of a support sleeve to obtain a semi-finished membrane;

[0021] (3) sintering: sintering the semi-finished membrane to obtain the ultra-high molecular weight polyethylene hollow fiber composite membrane.

[0022] Preferably, the average pore size of the flat plate ultra-high molecular weight polyethylene porous membrane in step (1) is 0.01-5 μm.

[0023] Preferably, the thickness of the flat plate ultra-high molecular weight polyethylene porous membrane in step (1) is 2-50 μm.

[0024] Preferably, the width of the flat plate ultra-high molecular weight polyethylene porous membrane in step (1) is 0.2-2 m.

[0025] Preferably, the pure water flux of the flat plate ultra-high molecular weight polyethylene porous membrane in step (1) at 25℃ is 10-10000 L / m 2 ·h·bar.

[0026] Preferably, in the slitting process of step (1), the longitudinal stretching rate is ≤5%, and the transverse shrinkage rate is ≤5%.

[0027] Preferably, the width of the narrow strip in step (1) is 5-50 mm.

[0028] Preferably, the outer diameter of the support sleeve in step (2) is 0.8-6mm.

[0029] Preferably, the inner diameter of the support sleeve in step (2) is 0.3-5.3mm.

[0030] Preferably, the temperature of the sintering treatment in step (3) is 110-150℃.

[0031] Preferably, the time of the sintering treatment in step (3) is 25-93s.

[0032] As a preferred technical solution of the second aspect of the present application, the preparation method comprises the following steps:

[0033] (1) slitting: using a slitting machine to slit a flat plate ultra-high molecular weight polyethylene porous membrane into a narrow strip with a width of 5-50mm; the flat plate ultra-high molecular weight polyethylene porous membrane has an average pore size of 0.01-5μm, a thickness of 2-50μm, a width of 0.2-2m, and a pure water flux of 10-10000L / m 2 ·h·bar; during the slitting process, the longitudinal elongation rate is ≤5%, and the transverse shrinkage rate is ≤5%;

[0034] (2) winding: feeding the narrow strip into a winding device to be wound on the outer surface of a support sleeve with an outer diameter of 0.8-6mm and an inner diameter of 0.3-5.3mm, to obtain a semi-finished membrane;

[0035] (3) sintering: feeding the semi-finished membrane into a heating oven to perform sintering treatment at 110-150℃ for 25-93s, to obtain the ultra-high molecular weight polyethylene hollow fiber composite membrane.

[0036] Thirdly, the present application provides an application of the ultra-high molecular weight polyethylene hollow fiber composite membrane according to the second aspect, which is used for water resource purification, industrial fluid separation or biomedicine purification.

[0037] Compared with the prior art, the present application has the following beneficial effects:

[0038] (1) The hollow fiber composite membrane provided by the present application has an inner-outer composite multi-skin layer structure, which organically combines the supporting effect of the support sleeve and the filtering effect of the filter layer group, and takes into account the filtering performance and structural stability of the composite membrane. In particular, the filter layer group relies on the characteristics of ultra-high molecular weight polyethylene and has high strength and excellent wear resistance, chemical resistance and anti-pollution properties, which can meet the precise filtration needs of different scenes and effectively solve the application limitations caused by performance defects of traditional membranes.

[0039] (2) The application adopts a three-step method of slitting-winding-sintering to prepare the ultra-high molecular weight polyethylene hollow fiber composite membrane, which can realize continuous production without traditional spinning process, and compared with traditional wet process and hot process, the three-step method saves the complex solvent treatment step, has high raw material utilization rate, and fully reduces the production cost, so it is suitable for industrial popularization and application. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is a schematic diagram of the ultra-high molecular weight polyethylene hollow fiber composite membrane provided by the application;

[0041] Figure 2 is a scanning electron microscope photograph of the surface of the ultra-high molecular weight polyethylene hollow fiber composite membrane provided in Example 1;

[0042] Figure 3 is a scanning electron microscope photograph of the overall cross section of the ultra-high molecular weight polyethylene hollow fiber composite membrane provided in Example 1;

[0043] Figure 4 is a scanning electron microscope photograph of the local cross section of the ultra-high molecular weight polyethylene hollow fiber composite membrane provided in Example 1.

[0044] 1 - support sleeve; 2 - filter layer group. DETAILED DESCRIPTION

[0045] The technical solutions of the application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the application and should not be regarded as specific limitations on the application.

[0046] An embodiment in the application provides an ultra-high molecular weight polyethylene hollow fiber composite membrane, which is an inner-outer composite multi-skin structure, comprising a support sleeve and a filter layer group wound on the outer surface of the support sleeve.

[0047] The material of the filter layer group is ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene has a bidirectional stretching net-like porous structure; and the preparation method of the ultra-high molecular weight polyethylene hollow fiber composite membrane comprises slitting, winding and sintering in sequence.

[0048] The hollow fiber composite membrane provided by the application has an inner-outer composite multi-skin structure, organically combines the supporting effect of the support sleeve and the filtering effect of the filter layer group, takes into account the filtering performance and structural stability of the composite membrane, and in particular, the filter layer group has high strength and excellent wear resistance, chemical resistance and pollution resistance relying on the characteristics of the ultra-high molecular weight polyethylene, can meet the precise filtration needs of different scenes, and effectively solves the application limitation of traditional membranes caused by performance defects.

[0049] The ultra-high molecular weight polyethylene adopted by the present application is a linear structure thermoplastic engineering plastic, as the third generation of high-performance fiber after carbon fiber and aramid, the ultra-high molecular weight polyethylene fiber has the characteristics of high strength and light weight, and the extremely high molecular weight endows it with excellent performance, such as excellent wear resistance, which is the first among various plastics, impact resistance ranks first among all engineering plastics, self-lubricating property is only second to polytetrafluoroethylene, excellent chemical resistance, can resist corrosion of various acid, alkali salt, oxidizing agent solution, almost insoluble in any organic solvent except naphthalene solvent.

[0050] However, due to the average molecular weight of ultra-high molecular weight polyethylene (more than 1 million) is much higher than that of low density polyethylene (several ten thousand to several hundred thousand) and high density polyethylene (several hundred thousand), the extremely high molecular weight makes the molecular chain entanglement serious, and the melt viscosity is extremely large (almost no flow at room temperature), which is difficult to process by traditional membrane preparation process (such as wet spinning, melt extrusion). For example, traditional wet spinning needs to dissolve the polymer in the solvent to form a uniform spinning solution, as mentioned above, ultra-high molecular weight polyethylene is almost insoluble in any organic solvent except naphthalene solvent, so it cannot form a homogeneous solution for spinning; when melt extrusion, the high viscosity of the material makes it difficult to flow uniformly in the mold, so it cannot be shaped into a continuous hollow fiber structure, which ultimately leads to a long-term blank in the application of this high-performance material in the field of membrane separation.

[0051] To this end, based on sufficient experiments and industrial trials and industrial application, the present application adopts a three-step method of "slitting-winding-sintering" to prepare ultra-high molecular weight polyethylene hollow fiber composite membrane, which can realize continuous production without traditional spinning process, and compared with traditional wet and hot process, the above three-step method saves the complex solvent treatment step, has high raw material utilization rate, and greatly reduces the production cost, which is suitable for industrial popularization and application.

[0052] In some embodiments, the support sleeve is an organic fiber braided sleeve, and the material includes any one or a combination of at least two of polyester, aramid, ultra-high molecular weight polyethylene, polypropylene, acrylic, polyamide or polyphenylene sulfide, typical but non-limiting combinations include a combination of polyester and aramid, a combination of aramid and ultra-high molecular weight polyethylene, a combination of ultra-high molecular weight polyethylene and polypropylene, a combination of polypropylene and acrylic, a combination of acrylic and polyamide, or a combination of polyamide and polyphenylene sulfide.

[0053] In some embodiments, the number of layers of the filter layer group is ≤8 layers, for example, it can be 1 layer, 2 layers, 3 layers, 4 layers, 5 layers, 6 layers, 7 layers or 8 layers, but is not limited to the listed values, and other values not listed in this range are also applicable.

[0054] In some embodiments, the average molecular weight of the ultra-high molecular weight polyethylene is ≥ 10 million, for example, it can be 10 million, 11 million, 12 million, 13 million, 14 million, 15 million, 16 million, 17 million, 18 million, 19 million, or 20 million, but not limited to the listed values, other values not listed in the range are also applicable.

[0055] In the present application, the average molecular weight refers to the weight average molecular weight.

[0056] In some embodiments, the nominal pore size of the ultra-high molecular weight polyethylene hollow fiber composite membrane is 0.005-2.5 μm, for example, it can be 0.005 μm, 0.01 μm, 0.05 μm, 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, or 2.5 μm, but not limited to the listed values, other values not listed in the range are also applicable.

[0057] In some embodiments, the pure water flux of the ultra-high molecular weight polyethylene hollow fiber composite membrane at 25°C is 5-5000 L / m 2 ·h·bar, for example, it can be 5 L / m 2 ·h·bar, 10 L / m 2 ·h·bar, 50 L / m 2 ·h·bar, 100 L / m 2 ·h·bar, 500 L / m 2 ·h·bar, 1000 L / m 2 ·h·bar, 1500 L / m 2 ·h·bar, 2000 L / m 2 ·h·bar, 2500 L / m 2 ·h·bar, 3000 L / m 2 ·h·bar, 3500 L / m 2 ·h·bar, 4000 L / m 2 ·h·bar, 4500 L / m 2 ·h·bar, or 5000 L / m 2 ·h·bar, but not limited to the listed values, other values not listed in the range are also applicable.

[0058] Some embodiments of the present application also provide a preparation method of the ultra-high molecular weight polyethylene hollow fiber composite membrane of any of the above embodiments, which comprises the following steps:

[0059] (1) Slitting: slitting the flat plate ultra-high molecular weight polyethylene porous membrane into a narrow strip;

[0060] (2) winding: winding the narrow strip on the outer surface of the support sleeve to obtain a semi-finished film;

[0061] (3) sintering: sintering the semi-finished film to obtain the ultra-high molecular weight polyethylene hollow fiber composite film.

[0062] In some embodiments, the flat plate ultra-high molecular weight polyethylene porous membrane in step (1) has an average pore size of 0.01-5 μm, for example, it can be 0.01 μm, 0.05 μm, 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm or 5 μm, but not limited to the listed values, other values not listed in the range are also applicable.

[0063] In some embodiments, the flat plate ultra-high molecular weight polyethylene porous membrane in step (1) has a thickness of 2-50 μm, for example, it can be 2 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm, but not limited to the listed values, other values not listed in the range are also applicable.

[0064] In some embodiments, the flat plate ultra-high molecular weight polyethylene porous membrane in step (1) has a width of 0.2-2 m, for example, it can be 0.2 m, 0.4 m, 0.6 m, 0.8 m, 1 m, 1.2 m, 1.4 m, 1.6 m, 1.8 m or 2 m, but not limited to the listed values, other values not listed in the range are also applicable.

[0065] In some embodiments, the flat plate ultra-high molecular weight polyethylene porous membrane in step (1) has a pure water flux of 10-10000 L / m 2 ·h·bar, for example, it can be 10 L / m 2 ·h·bar, 50 L / m 2 ·h·bar, 100 L / m 2 ·h·bar, 500 L / m 2 ·h·bar, 1000 L / m 2 ·h·bar, 2000 L / m 2 ·h·bar, 3000 L / m 2 ·h·bar, 4000 L / m 2 ·h·bar, 5000 L / m 2 ·h·bar, 6000 L / m 2 ·h·bar, 7000 L / m 2 ·h·bar, 8000 L / m 2• h bar, 9000 L / m 2 • h bar, 10000 L / m 2 • h bar, but other unrecited values within the range are also applicable.

[0066] In certain embodiments, the slitting process of step (1) has a machine direction stretch of < 5%, such as 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%, and a cross direction shrink of < 5%, such as 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%, but other unrecited values within the range are also applicable.

[0067] In certain embodiments, the strip of step (1) has a width of 5-50 mm, such as 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, or 50 mm, but other unrecited values within the range are also applicable.

[0068] In certain embodiments, the support sleeve of step (2) has an outer diameter of 0.8-6 mm, such as 0.8 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, or 6 mm, but other unrecited values within the range are also applicable.

[0069] In certain embodiments, the support sleeve of step (2) has an inner diameter of 0.3-5.3 mm, such as 0.3 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, or 5.3 mm, but other unrecited values within the range are also applicable.

[0070] In certain embodiments, the sintering process of step (3) has a temperature of 110-150 °C, such as 110 °C, 115 °C, 120 °C, 125 °C, 130 °C, 135 °C, 140 °C, 145 °C, or 150 °C, but other unrecited values within the range are also applicable.

[0071] In some embodiments, the sintering process in step (3) is performed for a time period of 25-93 seconds, for example, 25 seconds, 30 seconds, 35 seconds, 40 seconds, 45 seconds, 50 seconds, 55 seconds, 60 seconds, 65 seconds, 70 seconds, 75 seconds, 80 seconds, 85 seconds, 90 seconds, or 93 seconds, but not limited to the listed values, and other values not listed within the range are also applicable.

[0072] In some embodiments, the preparation method comprises the following steps:

[0073] (1) slitting: using a slitting machine to slit a flat plate of the ultra-high molecular weight polyethylene porous membrane into a narrow strip with a width of 5-50 mm; the flat plate of the ultra-high molecular weight polyethylene porous membrane has an average pore size of 0.01-5 μm, a thickness of 2-50 μm, a width of 0.2-2 m, and a pure water flux of 10-10000 L / m 2 ·h·bar; during the slitting process, the longitudinal stretching rate is ≤5%, and the transverse shrinkage rate is ≤5%;

[0074] (2) winding: feeding the narrow strip into a winding device to be wound on the outer surface of a support sleeve with an outer diameter of 0.8-6 mm and an inner diameter of 0.3-5.3 mm to obtain a semi-finished membrane;

[0075] (3) sintering: feeding the semi-finished membrane into a heating oven to perform sintering treatment at 110-150°C for 25-93 seconds to obtain the ultra-high molecular weight polyethylene hollow fiber composite membrane.

[0076] Some embodiments of the present application also provide an application of the ultra-high molecular weight polyethylene hollow fiber composite membrane according to any one of the above embodiments, which is used for water resource purification, industrial fluid separation, or biopharmaceutical purification.

[0077] The numerical ranges recited in the present application include not only the explicitly recited points, but also any points between the explicitly recited points within the range. Due to the limited space and for the sake of simplicity, the present application does not list all the specific point values included in the range.

[0078] Example 1

[0079] The present embodiment provides an ultra-high molecular weight polyethylene hollow fiber composite membrane and a preparation method thereof, as shown in Figure 1 The ultra-high molecular weight polyethylene hollow fiber composite membrane has an inner-outer composite multi-skin layer structure, comprising a support sleeve 1 and a filter layer group 2 wound on the outer surface of the support sleeve 1. The filter layer group 2 is made of ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene has a bidirectional stretching net-like porous structure.

[0080] Specifically, the support sleeve 1 is an organic fiber braided sleeve made of polyester; the filter layer group 2 has three layers; and the average molecular weight of the ultra-high molecular weight polyethylene is 3 million.

[0081] The preparation method of the above-mentioned ultra-high molecular weight polyethylene hollow fiber composite membrane comprises the following steps:

[0082] (1) Slitting: using a slitting machine to slit the flat plate ultra-high molecular weight polyethylene porous membrane into a narrow strip with a width of 15 mm; the flat plate ultra-high molecular weight polyethylene porous membrane has an average pore size of 0.05 μm, a thickness of 16 μm, a width of 0.5 m, and a pure water flux of 1200 L / m 2 ·h·bar; during the slitting process, the longitudinal stretching rate is ≤5%, and the transverse shrinkage rate is ≤5%;

[0083] (2) Winding: feeding the narrow strip into a winding device to be wound on the outer surface of an organic fiber braided sleeve with an outer diameter of 2.45 mm and an inner diameter of 1.6 mm to obtain a semi-finished membrane;

[0084] (3) Sintering: feeding the semi-finished membrane into a heating oven to perform sintering treatment at 131 ℃ for 87 s, so that the winding joint is fused and sealed, and the pore size is further reduced to obtain the ultra-high molecular weight polyethylene hollow fiber composite membrane.

[0085] The surface electron microscope micrograph, the overall cross-sectional electron microscope micrograph, and the local cross-sectional electron microscope micrograph of the hollow fiber composite membrane obtained in this embodiment are respectively Figure 2 、 Figure 3 and Figure 4 .

[0086] Example 2

[0087] This embodiment provides an ultra-high molecular weight polyethylene hollow fiber composite membrane and a preparation method thereof, as shown in Figure 1 The ultra-high molecular weight polyethylene hollow fiber composite membrane has an inner-outer composite multi-skin layer structure, which comprises a support sleeve 1 and a filter layer group 2 wound on the outer surface of the support sleeve 1. The filter layer group 2 is made of ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene has a bidirectional stretching net-like porous structure.

[0088] Specifically, the support sleeve 1 is an organic fiber braided sleeve made of polyester; the filter layer group 2 has two layers; and the average molecular weight of the ultra-high molecular weight polyethylene is 4 million.

[0089] The preparation method of the above-mentioned ultra-high molecular weight polyethylene hollow fiber composite membrane comprises the following steps:

[0090] (1) slitting: using a slitting machine to slit a flat plate of ultra-high molecular weight polyethylene porous membrane into a narrow strip with a width of 20 mm; the flat plate of ultra-high molecular weight polyethylene porous membrane has an average pore size of 0.04 μm, a thickness of 12 μm, a width of 1 m, and a pure water flux of 1500 L / m 2 ·h·bar; during the slitting process, the longitudinal stretching rate is ≤5%, and the transverse shrinkage rate is ≤5%;

[0091] (2) winding: feeding the narrow strip into a winding device to be wound on the outer surface of an organic fiber braided sleeve with an outer diameter of 2.45 mm and an inner diameter of 1.6 mm to obtain a semi-finished membrane;

[0092] (3) sintering: feeding the semi-finished membrane into a heating oven for sintering treatment at 130°C for 80s, so that the winding joint is fused and sealed, and the pore size is further reduced to obtain the ultra-high molecular weight polyethylene hollow fiber composite membrane.

[0093] The surface morphology, overall cross-sectional morphology and local cross-sectional morphology of the hollow fiber composite membrane obtained in this example are similar to those of Example 1, and therefore are not described here.

[0094] Example 3

[0095] This example provides an ultra-high molecular weight polyethylene hollow fiber composite membrane and a preparation method thereof, as shown in Figure 1 The ultra-high molecular weight polyethylene hollow fiber composite membrane has an inner-outer composite multi-skin layer structure, which includes a support sleeve 1 and a filter layer group 2 wound on the outer surface of the support sleeve 1. The material of the filter layer group 2 is ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene has a bidirectional stretching net-like porous structure.

[0096] Specifically, the support sleeve 1 is an organic fiber braided sleeve made of polyester; the filter layer group 2 has 4 layers; and the average molecular weight of the ultra-high molecular weight polyethylene is 1.5 million.

[0097] The preparation method of the above-mentioned ultra-high molecular weight polyethylene hollow fiber composite membrane includes the following steps:

[0098] (1) slitting: using a slitting machine to slit a flat plate of ultra-high molecular weight polyethylene porous membrane into a narrow strip with a width of 20 mm; the flat plate of ultra-high molecular weight polyethylene porous membrane has an average pore size of 0.01 μm, a thickness of 20 μm, a width of 0.5 m, and a pure water flux of 620 L / m 2 ·h·bar; during the slitting process, the longitudinal stretching rate is ≤5%, and the transverse shrinkage rate is ≤5%;

[0099] (2) winding: the narrow strip is sent into a winding device and wound on the outer surface of an organic fiber woven sleeve with an outer diameter of 1.9 mm and an inner diameter of 1.1 mm to obtain a semi-finished product film;

[0100] (3) sintering: the semi-finished product film is sent into a heating oven, sintering treatment is carried out at 132 ℃ for 70 s, the winding joint is fused and sealed, and the pore size is further reduced to obtain the ultra-high molecular weight polyethylene hollow fiber composite film.

[0101] The surface morphology, overall cross-sectional morphology and local cross-sectional morphology of the hollow fiber composite film obtained in the example are similar to those of example 1, and therefore will not be described here.

[0102] Example 4

[0103] The example provides an ultra-high molecular weight polyethylene hollow fiber composite film and a preparation method thereof, as shown in the figure, the ultra-high molecular weight polyethylene hollow fiber composite film has an inner-outer composite multi-skin layer structure, which comprises a support sleeve 1 and a filter layer group 2 wound on the outer surface of the support sleeve 1. Figure 1 The material of the filter layer group 2 is ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene has a bidirectional stretching net-like porous structure.

[0104] Specifically, the support sleeve 1 is an organic fiber woven sleeve, and the material is ultra-high molecular weight polyethylene; the number of layers of the filter layer group 2 is 3; and the average molecular weight of the ultra-high molecular weight polyethylene is 2 million.

[0105] The preparation method of the above-mentioned ultra-high molecular weight polyethylene hollow fiber composite film comprises the following steps:

[0106] (1) slitting: a flat plate ultra-high molecular weight polyethylene porous film is slitted into a narrow strip with a width of 25 mm by using a slitting machine; the average pore size of the flat plate ultra-high molecular weight polyethylene porous film is 0.02 μm, the thickness is 50 μm, the width is 2 m, and the pure water flux at 25 ℃ is 380 L / m 2 ·h·bar; during the slitting process, the longitudinal stretching rate is ≤5%, and the transverse shrinkage rate is ≤5%;

[0107] (2) winding: the narrow strip is sent into a winding device and wound on the outer surface of an organic fiber woven sleeve with an outer diameter of 1.9 mm and an inner diameter of 1.1 mm to obtain a semi-finished product film;

[0108] (3) sintering: the semi-finished product film is sent into a heating oven, sintering treatment is carried out at 133 ℃ for 93 s, the winding joint is fused and sealed, and the pore size is further reduced to obtain the ultra-high molecular weight polyethylene hollow fiber composite film.

[0109] The surface morphology, overall cross-sectional morphology and local cross-sectional morphology of the hollow fiber composite membrane obtained in this example are similar to those of Example 1, and thus are not described here.

[0110] Example 5

[0111] This example provides a kind of ultra-high molecular weight polyethylene hollow fiber composite membrane and its preparation method, as shown in Figure 1 The ultra-high molecular weight polyethylene hollow fiber composite membrane is an inner-outer composite multi-skin structure, comprising a support sleeve 1 and a filter layer group 2 wound on the outer surface of the support sleeve 1. The material of the filter layer group 2 is ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene has a bidirectional stretching net-like porous structure.

[0112] Specifically, the support sleeve 1 is an organic fiber braided sleeve, and the material is polyester; the number of layers of the filter layer group 2 is 5 layers; the average molecular weight of the ultra-high molecular weight polyethylene is 1.8 million.

[0113] The preparation method of the above-mentioned ultra-high molecular weight polyethylene hollow fiber composite membrane comprises the following steps:

[0114] (1) Slitting: using a slitting machine to slit a flat plate ultra-high molecular weight polyethylene porous membrane into a narrow strip with a width of 50 mm; the average pore size of the flat plate ultra-high molecular weight polyethylene porous membrane is 0.2 μm, the thickness is 30 μm, the width is 0.3 m, and the pure water flux at 25 ℃ is 3200 L / m 2 ·h·bar; during the slitting process, the longitudinal stretching rate is ≤5%, and the transverse shrinkage rate is ≤5%;

[0115] (2) Winding: the narrow strip is sent into a winding device and wound on the outer surface of an organic fiber braided sleeve with an outer diameter of 2.45 mm and an inner diameter of 1.6 mm to obtain a semi-finished product membrane;

[0116] (3) Sintering: the semi-finished product membrane is sent into a heating oven for sintering treatment at 135 ℃ for 61 s, so that the winding joint is fused and sealed, and the pore size is further reduced to obtain the ultra-high molecular weight polyethylene hollow fiber composite membrane.

[0117] The surface morphology, overall cross-sectional morphology and local cross-sectional morphology of the hollow fiber composite membrane obtained in this example are similar to those of Example 1, and thus are not described here.

[0118] Example 6

[0119] This example provides a kind of ultra-high molecular weight polyethylene hollow fiber composite membrane and its preparation method, as shown in Figure 1As shown in the figure, the ultra-high molecular weight polyethylene hollow fiber composite membrane is an inner-outer composite multi-skin structure, including a support sleeve 1 and a filter layer group 2 wound on the outer surface of the support sleeve 1. The material of the filter layer group 2 is ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene has a bidirectional stretching net-like porous structure.

[0120] Specifically, the support sleeve 1 is an organic fiber woven sleeve, and the material is polypropylene; the number of layers of the filter layer group 2 is 8 layers; and the average molecular weight of the ultra-high molecular weight polyethylene is 3 million.

[0121] The preparation method of the above-mentioned ultra-high molecular weight polyethylene hollow fiber composite membrane comprises the following steps:

[0122] (1) Slitting: using a slitting machine to slit a flat plate ultra-high molecular weight polyethylene porous membrane into a narrow strip with a width of 10 mm; the average pore size of the flat plate ultra-high molecular weight polyethylene porous membrane is 5 μm, the thickness is 3 μm, the width is 1.8 m, and the pure water flux at 25°C is 9850 L / m 2 ·h·bar; during the slitting process, the longitudinal stretching rate is ≤5%, and the transverse shrinkage rate is ≤5%;

[0123] (2) Winding: feeding the narrow strip into a winding device to be wound on the outer surface of an organic fiber woven sleeve with an outer diameter of 1.9 mm and an inner diameter of 1.1 mm to obtain a semi-finished product membrane;

[0124] (3) Sintering: feeding the semi-finished product membrane into a heating oven to perform sintering treatment at 150°C for 25s, so that the wound joint is fused and sealed, and the pore size is further reduced to obtain the ultra-high molecular weight polyethylene hollow fiber composite membrane.

[0125] The surface morphology, overall cross-sectional morphology and local cross-sectional morphology of the hollow fiber composite membrane obtained in this example are similar to those of Example 1, and therefore will not be described here.

[0126] Example 7

[0127] This example provides an ultra-high molecular weight polyethylene hollow fiber composite membrane and a preparation method thereof, as shown in the figure, Figure 1 As shown in the figure, the ultra-high molecular weight polyethylene hollow fiber composite membrane is an inner-outer composite multi-skin structure, including a support sleeve 1 and a filter layer group 2 wound on the outer surface of the support sleeve 1. The material of the filter layer group 2 is ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene has a bidirectional stretching net-like porous structure.

[0128] Specifically, the support sleeve 1 is an organic fiber woven sleeve, and the material is polypropylene; the number of layers of the filter layer group 2 is 8 layers; and the average molecular weight of the ultra-high molecular weight polyethylene is 3 million.

[0129] The preparation method of the above-mentioned ultra-high molecular weight polyethylene hollow fiber composite membrane comprises the following steps:

[0130] (1) Slitting: using a slitting machine to slit the flat plate ultra-high molecular weight polyethylene porous membrane into a narrow strip with a width of 5 mm; the average pore size of the flat plate ultra-high molecular weight polyethylene porous membrane is 0.01 μm, the thickness is 2 μm, the width is 0.2 m, and the pure water flux under the condition of 25℃ is 20 L / m 2 ·h·bar; during the slitting process, the longitudinal stretching rate is ≤5%, and the transverse shrinkage rate is ≤5%;

[0131] (2) Winding: the narrow strip is sent into a winding device and wound on the outer surface of an organic fiber braided sleeve with an outer diameter of 5.96 mm and an inner diameter of 5.3 mm to obtain a semi-finished membrane;

[0132] (3) Sintering: the semi-finished membrane is sent into a heating oven and sintered at 110℃ for 93 s to make the winding joint fused and sealed, and the pore size is further reduced to obtain the ultra-high molecular weight polyethylene hollow fiber composite membrane.

[0133] The surface morphology, overall cross-sectional morphology and local cross-sectional morphology of the hollow fiber composite membrane obtained in this example are similar to those of Example 1, so they are not described here.

[0134] Example 8

[0135] This example provides an ultra-high molecular weight polyethylene hollow fiber composite membrane and a preparation method thereof, as shown in Figure 1 The ultra-high molecular weight polyethylene hollow fiber composite membrane has an inner-outer composite multi-skin layer structure, which comprises a support sleeve 1 and a filter layer group 2 wound on the outer surface of the support sleeve 1. The material of the filter layer group 2 is ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene has a bidirectional stretching net-like porous structure.

[0136] Specifically, the support sleeve 1 is an organic fiber braided sleeve, and the material is nylon; the number of layers of the filter layer group 2 is 1.2 layers; the average molecular weight of the ultra-high molecular weight polyethylene is 5 million.

[0137] The preparation method of the above-mentioned ultra-high molecular weight polyethylene hollow fiber composite membrane comprises the following steps:

[0138] (1) Slitting: using a slitting machine to slit the flat plate ultra-high molecular weight polyethylene porous membrane into a narrow strip with a width of 40 mm; the average pore size of the flat plate ultra-high molecular weight polyethylene porous membrane is 0.13 μm, the thickness is 40 μm, the width is 2 m, and the pure water flux under the condition of 25℃ is 3738 L / m 2 ·h·bar; during the slitting process, the longitudinal stretching rate is ≤5%, and the transverse shrinkage rate is ≤5%;

[0139] (2) winding: the narrow strip is sent into a winding device and wound on the outer surface of an organic fiber woven sleeve with an outer diameter of 1.3 mm and an inner diameter of 0.6 mm to obtain a semi-finished product film;

[0140] (3) sintering: the semi-finished product film is sent into a heating oven, sintering treatment is carried out at 140°C for 80s, the winding joint is fused and sealed, and the pore size is further reduced to obtain the ultra-high molecular weight polyethylene hollow fiber composite film.

[0141] The surface morphology, overall cross-sectional morphology and local cross-sectional morphology of the hollow fiber composite film obtained in the example are similar to those of example 1, and therefore are not described here.

[0142] Example 9

[0143] The example provides an ultra-high molecular weight polyethylene hollow fiber composite film and a preparation method thereof, as shown in the following scheme, the ultra-high molecular weight polyethylene hollow fiber composite film has an inner-outer composite multi-skin layer structure, which comprises a support sleeve 1 and a filter layer group 2 wound on the outer surface of the support sleeve 1. Figure 1 The material of the filter layer group 2 is ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene has a bidirectional stretching net-like porous structure.

[0144] Specifically, the support sleeve 1 is an organic fiber woven sleeve, and the material is polyester; the number of layers of the filter layer group 2 is 3.2 layers; the average molecular weight of the ultra-high molecular weight polyethylene is 4 million.

[0145] The preparation method of the above-mentioned ultra-high molecular weight polyethylene hollow fiber composite film comprises the following steps:

[0146] (1) slitting: a flat plate ultra-high molecular weight polyethylene porous film is slitted into a narrow strip with a width of 15 mm by using a slitting machine; the average pore size of the flat plate ultra-high molecular weight polyethylene porous film is 0.08 μm, the thickness is 12 μm, the width is 1 m, and the pure water flux at 25°C is 3678 L / m 2 ·h·bar; during the slitting process, the longitudinal stretching rate is ≤5%, and the transverse shrinkage rate is ≤5%;

[0147] (2) winding: the narrow strip is sent into a winding device and wound on the outer surface of an organic fiber woven sleeve with an outer diameter of 1.9 mm and an inner diameter of 1.1 mm to obtain a semi-finished product film;

[0148] (3) sintering: the semi-finished product film is sent into a heating oven, sintering treatment is carried out at 132.1°C for 80s, the winding joint is fused and sealed, and the pore size is further reduced to obtain the ultra-high molecular weight polyethylene hollow fiber composite film.

[0149] The surface morphology, overall cross-sectional morphology, and local cross-sectional morphology of the hollow fiber composite membrane obtained in this embodiment are similar to those in Embodiment 1, so they will not be described again here.

[0150] Example 10

[0151] This embodiment provides an ultra-high molecular weight polyethylene hollow fiber composite membrane and its preparation method, such as... Figure 1 As shown, the ultra-high molecular weight polyethylene hollow fiber composite membrane has an inner and outer composite multi-layer structure, including a support sleeve 1 and a filter layer group 2 wrapped around the outer surface of the support sleeve 1. The filter layer group 2 is made of ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene has a biaxially stretched mesh porous structure.

[0152] Specifically, the support sleeve 1 is an organic fiber braided sleeve made of polyester; the filter layer group 2 has 2.8 layers; and the ultra-high molecular weight polyethylene has an average molecular weight of 2.5 million.

[0153] The preparation method of the above-mentioned ultra-high molecular weight polyethylene hollow fiber composite membrane includes the following steps:

[0154] (1) Slitting: The flat ultra-high molecular weight polyethylene porous membrane is slitted into narrow strips with a width of 20 mm using a slitting machine; the flat ultra-high molecular weight polyethylene porous membrane has an average pore size of 0.03 μm, a thickness of 18 μm, a width of 0.5 m, and a pure water flux of 2080 L / m at 25℃. 2 •h·bar; During the cutting process, the longitudinal stretching rate is ≤5%, and the transverse shrinkage rate is ≤5%;

[0155] (2) Winding: The narrow strip is fed into a winding device and wound around the outer surface of an organic fiber braided sleeve with an outer diameter of 1.9 mm and an inner diameter of 1.1 mm to obtain a semi-finished film;

[0156] (3) Sintering: The semi-finished film is sent into the heating oven and sintered at 133°C for 74s to fuse and seal the winding seams and further reduce the pore size to obtain the ultra-high molecular weight polyethylene hollow fiber composite film.

[0157] The surface morphology, overall cross-sectional morphology, and local cross-sectional morphology of the hollow fiber composite membrane obtained in this embodiment are similar to those in Embodiment 1, so they will not be described again here.

[0158] Example 11

[0159] This embodiment provides an ultra-high molecular weight polyethylene hollow fiber composite membrane and its preparation method, such as... Figure 1As shown in the figure, the ultra-high molecular weight polyethylene hollow fiber composite membrane is an inner-outer composite multi-skin structure, including a support sleeve 1 and a filter layer group 2 wound on the outer surface of the support sleeve 1. The material of the filter layer group 2 is ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene has a bidirectional stretching net-like porous structure.

[0160] Specifically, the support sleeve 1 is an organic fiber woven sleeve, and the material is polyester; the number of layers of the filter layer group 2 is 4.6 layers; and the average molecular weight of the ultra-high molecular weight polyethylene is 5.5 million.

[0161] The preparation method of the above-mentioned ultra-high molecular weight polyethylene hollow fiber composite membrane comprises the following steps:

[0162] (1) Slitting: using a slitting machine to slit a flat plate ultra-high molecular weight polyethylene porous membrane into a narrow strip with a width of 26 mm; the average pore size of the flat plate ultra-high molecular weight polyethylene porous membrane is 0.5 μm, the thickness is 33 μm, the width is 1.5 m, and the pure water flux under the condition of 25℃ is 7650 L / m 2 ·h·bar; during the slitting process, the longitudinal stretching rate is ≤5%, and the transverse shrinkage rate is ≤5%;

[0163] (2) Winding: feeding the narrow strip into a winding device to be wound on the outer surface of an organic fiber woven sleeve with an outer diameter of 2.45 mm and an inner diameter of 1.6 mm to obtain a semi-finished product membrane;

[0164] (3) Sintering: feeding the semi-finished product membrane into a heating oven to perform sintering treatment at 141℃ for 39 s, so that the winding joint is fused and sealed, and the pore size is further reduced to obtain the ultra-high molecular weight polyethylene hollow fiber composite membrane.

[0165] The surface morphology, overall cross-sectional morphology and local cross-sectional morphology of the hollow fiber composite membrane obtained in this example are similar to those of Example 1, and therefore will not be described here.

[0166] Example 12

[0167] This example provides an ultra-high molecular weight polyethylene hollow fiber composite membrane and a preparation method thereof, as shown in the figure, Figure 1 As shown in the figure, the ultra-high molecular weight polyethylene hollow fiber composite membrane is an inner-outer composite multi-skin structure, including a support sleeve 1 and a filter layer group 2 wound on the outer surface of the support sleeve 1. The material of the filter layer group 2 is ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene has a bidirectional stretching net-like porous structure.

[0168] Specifically, the support sleeve 1 is an organic fiber woven sleeve, and the material is aramid; the number of layers of the filter layer group 2 is 4 layers; and the average molecular weight of the ultra-high molecular weight polyethylene is 5.5 million.

[0169] The preparation method of the hollow fiber composite membrane of the above-mentioned ultra-high molecular weight polyethylene comprises the following steps:

[0170] (1) slitting: using a slitting machine to slit the flat plate ultra-high molecular weight polyethylene porous membrane into a narrow strip with a width of 26 mm; the average pore size of the flat plate ultra-high molecular weight polyethylene porous membrane is 0.5 μm, the thickness is 33 μm, the width is 1.5 m, and the pure water flux under the condition of 25℃ is 7650 L / m 2 ·h·bar; during the slitting process, the longitudinal elongation rate is ≤5%, and the transverse shrinkage rate is ≤5%;

[0171] (2) winding: the narrow strip is sent into a winding device and wound on the outer surface of an organic fiber braided sleeve with an outer diameter of 2.45 mm and an inner diameter of 1.6 mm to obtain a semi-finished product membrane;

[0172] (3) sintering: the semi-finished product membrane is sent into a heating oven and sintered at 141℃ for 37s, so that the winding joint is fused and sealed, and the pore size is further reduced to obtain the ultra-high molecular weight polyethylene hollow fiber composite membrane.

[0173] The surface morphology, overall cross-sectional morphology and local cross-sectional morphology of the hollow fiber composite membrane obtained in this example are similar to those of Example 1, so they are not described here.

[0174] It is detected that the outer diameter, inner diameter, nominal pore size and pure water flux under the condition of 25℃ of the hollow fiber composite membrane obtained in Examples 1-12 are shown in the following Table 1.

[0175] Table 1

[0176]

[0177]

[0178] As can be seen, the hollow fiber composite membrane provided by the application has an inner-outer composite multi-skin structure, organically combining the supporting effect of the supporting sleeve and the filtering effect of the filter layer group, and taking into account the filtering performance and structural stability of the composite membrane. In particular, the filter layer group relies on the characteristics of ultra-high molecular weight polyethylene and has high strength and excellent wear resistance, chemical resistance and anti-pollution properties, which can meet the precise filtration needs of different scenes and effectively solve the application limitations caused by performance defects of traditional membranes.

[0179] In addition, the application adopts the three-step method of "slitting-winding-sintering" to prepare the ultra-high molecular weight polyethylene hollow fiber composite membrane, which does not need the traditional spinning process and can realize continuous production. Compared with the traditional wet process and hot process, the above-mentioned three-step method eliminates the complex solvent treatment step, has high raw material utilization rate, and sufficiently reduces the production cost, which is suitable for industrialized popularization and application.

[0180] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited thereto, and it should be understood by those skilled in the art that any change or replacement within the technical scope disclosed by the present application can be easily thought out by those skilled in the art, and falls within the protection scope and disclosure scope of the present application.

Claims

1. An ultra-high molecular weight polyethylene hollow fiber composite membrane, characterized by, The ultra-high molecular weight polyethylene hollow fiber composite membrane has an inner-outer composite multi-skin structure, comprising a support sleeve and a filter layer group wound on the outer surface of the support sleeve; The material of the filter layer group is ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene has a bidirectional stretching net-like porous structure; The preparation method of the ultra-high molecular weight polyethylene hollow fiber composite membrane comprises the steps of slitting, winding and sintering in sequence.

2. The ultra-high molecular weight polyethylene hollow fiber composite membrane according to claim 1, characterized by, The support sleeve is an organic fiber braided sleeve, and the material includes any one or a combination of at least two of polyester, aramid, ultra-high molecular weight polyethylene, polypropylene, acrylic, nylon or polyphenylene sulfide; And / or, the number of layers of the filter layer group is ≤8 layers; And / or, the average molecular weight of the ultra-high molecular weight polyethylene is ≥1 million.

3. The ultra-high molecular weight polyethylene hollow fiber composite membrane according to claim 1 or 2, characterized by, The nominal pore size of the ultra-high molecular weight polyethylene hollow fiber composite membrane is 0.005-2.5 μm; And / or, the pure water flux of the ultra-high molecular weight polyethylene hollow fiber composite membrane under the condition of 25℃ is 5-5000L / m 2 · h· bar.

4. A method for producing the ultra-high molecular weight polyethylene hollow fiber composite membrane according to any one of claims 1 to 3, characterized by, The preparation method comprises the following steps: (1) Slitting: slitting a flat plate ultra-high molecular weight polyethylene porous membrane into a narrow strip; (2) Winding: winding the narrow strip on the outer surface of the support sleeve to obtain a semi-finished product membrane; (3) Sintering: sintering the semi-finished product membrane to obtain the ultra-high molecular weight polyethylene hollow fiber composite membrane.

5. The preparation method according to claim 4, characterized in that, The average pore size of the flat plate ultra-high molecular weight polyethylene porous membrane in step (1) is 0.01-5 μm; And / or, the thickness of the flat plate ultra-high molecular weight polyethylene porous membrane in step (1) is 2-50 μm; And / or, the width of the flat plate ultra-high molecular weight polyethylene porous membrane in step (1) is 0.2-2 m; And / or, the flat plate ultra-high molecular weight polyethylene porous membrane in step (1) has a pure water flux of 10-10000 L / m at 25°C 2 · h·bar.

6. The preparation method according to claim 4, characterized in that, In the slitting process of step (1), the longitudinal stretching rate is ≤5%, and the transverse shrinkage rate is ≤5%; And / or, the width of the narrow strip in step (1) is 5-50 mm.

7. The preparation method according to claim 4, characterized in that, The outer diameter of the support sleeve in step (2) is 0.8-6 mm; And / or, the inner diameter of the support sleeve in step (2) is 0.3-5.3 mm.

8. The preparation method according to claim 4, characterized in that, The sintering temperature in step (3) is 110-150℃; And / or, the sintering time in step (3) is 25-93 s.

9. The method of any one of claims 4-8, wherein, The preparation method comprises the following steps: (1) slitting: using a slitter to slit the flat plate ultra-high molecular weight polyethylene porous membrane into a narrow strip with a width of 5-50 mm; the flat plate ultra-high molecular weight polyethylene porous membrane has an average pore size of 0.01-5 μm, a thickness of 2-50 μm, a width of 0.2-2 m, and a pure water flux of 10-10000 L / m 2 · h·bar; in the slitting process, the longitudinal elongation is ≤5%, and the transverse shrinkage is ≤5%; (2) Winding: feeding the narrow strip into a winding device and winding it on the outer surface of a support sleeve with an outer diameter of 0.8-6 mm and an inner diameter of 0.3-5.3 mm to obtain a semi-finished product membrane; (3) Sintering: feeding the semi-finished product membrane into a heating oven and sintering it at 110-150℃ for 25-93 s to obtain the ultra-high molecular weight polyethylene hollow fiber composite membrane.

10. Use of the ultra-high molecular weight polyethylene hollow fiber composite membrane according to any one of claims 1 to 3, characterized in that, The ultra-high molecular weight polyethylene hollow fiber composite membrane is used for water resource purification, industrial fluid separation or biopharmaceutical purification.

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