CN114797491B

CN114797491B - Filtering membrane package and preparation method thereof

Info

Publication number: CN114797491B
Application number: CN202210714378.2A
Authority: CN
Inventors: 贾建东
Original assignee: Hangzhou Cobetter Filtration Equipment Co Ltd
Current assignee: Hangzhou Cobetter Filtration Equipment Co Ltd
Priority date: 2022-06-23
Filing date: 2022-06-23
Publication date: 2022-10-04
Anticipated expiration: 2042-06-23
Also published as: CN114797491A

Abstract

The invention discloses a filter membrane package and a preparation method thereof, relating to the technical field of biological filtration and comprising a liquid inlet unit and a filtrate unit, wherein the filtrate unit comprises a filtrate screen and filter layers arranged on one side or two sides of the filtrate screen, and the filtrate screen forms a filtrate flow channel; the filtering layer comprises a cellulose filtering membrane, and the cellulose filtering membrane sequentially comprises a substrate layer, a supporting layer and a filtering membrane layer; the substrate layer comprises fibers which are interwoven with each other and form a net structure, and the substrate layer is provided with a first surface combined with the support layer and a second surface for penetrating the filtrate; the first surface comprises single fiber arrangement single silk areas and at least two fiber combination areas which are combined and arranged or interwoven with each other.

Description

Filtering membrane package and preparation method thereof

Technical Field

The invention relates to the technical field of biological filtration, in particular to a filter membrane package and a preparation method thereof.

Background

The separation and purification technology is an indispensable step in obtaining high-purity and high-activity biopharmaceutical products, and the separation and purification method comprises a flocculation precipitation method, a macroporous resin adsorption method, a membrane separation method, a high-speed centrifugation method and the like, wherein the membrane separation method comprises microfiltration, ultrafiltration and nanofiltration, and is a process for filtering substances with specific molecular weights, and the separation, concentration and purification of effective components can be completed by realizing the sieving effect through the pore diameter of a membrane by means of stable pressure and flow rate to force macromolecular substances to be intercepted and filter out small molecular components.

The membrane separation assembly comprises a pump, a membrane package, a pipeline, a pressure valve and the like, wherein the membrane package takes a filter screen as a support, takes a filter membrane as a filter medium, and is a core component of the membrane separation assembly for filtering by taking pressure difference as a driving force. The filtering membranes in the membrane package are separated by filtering screens, so that flow channels are formed.

The filter layer in the filter membrane package usually adopts the form of cellulose filtration membrane, when cellulose filtration membrane is prepared, cellulose needs to be coated on the substrate layer to obtain good strength, wherein the substrate layer adopts the form of non-woven fabric, the non-woven fabric has multiple preparation processes, such as spun-bonded hot-rolled non-woven fabric, wet-process non-woven fabric, needle-punched non-woven fabric, water-jet non-woven fabric, etc., however, the surface of the non-woven fabric is relatively rough, when cellulose is coated on the non-woven fabric substrate layer, the rough surface easily pokes the cellulose membrane surface formed by the cellulose coating liquid, thereby leading to the rupture of the cellulose membrane surface and influencing the subsequent filtering capability.

And, even in the membrane preparation process, the coarse surface of non-woven fabrics substrate layer can not destroy membrane surface structure, in the filter membrane package use, because modes such as anchor clamps need be adopted with the membrane package centre gripping, in the centre gripping in-process, cellulose filtration membrane can receive the compression to a certain extent, the coarse surface of substrate layer this moment, and the tip that fibre bellying and fibre perk on the surface also punctures the cellulose layer in the cellulose filtration membrane very easily, lead to the cellulose surface impaired, seriously influence its filter effect, also can further lead to the filterability of whole filter membrane package impaired.

Disclosure of Invention

The invention aims to provide a filter membrane pack which can prevent a cellulose filter layer from being punctured by a base material layer when the filter membrane pack is clamped for use, thereby having good filtering performance, high stability, high durability and long service life, and a preparation method thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

a filtration membrane package comprising, in combination,

the liquid inlet unit comprises a liquid inlet screen, and a liquid inlet flow channel is formed by the liquid inlet screen;

the filter unit comprises a filter screen and filter layers arranged on one side or two sides of the filter screen, and the filter screen forms a filter flow channel;

liquid inlet holes and filtrate holes are distributed on the side edges of the liquid inlet unit and the filtrate unit and are alternately stacked;

the filtering layer comprises a cellulose filtering membrane, and the cellulose filtering membrane sequentially comprises a substrate layer, a supporting layer and a filtering membrane layer;

the support layer partially or completely penetrates into the base material layer and is combined with the base material layer;

the filter membrane layer is combined with the support layer;

the substrate layer includes fibers that are interwoven with each other and form a network structure, and has:

a first surface bonded to the support layer, and a second surface through which the filtrate passes;

the first surface comprises a single silk area with single fibers arranged and a doubling area with at least two fibers arranged in a combining way or interwoven mutually.

During use, firstly, clamping a single filtering membrane package or a plurality of stacked filtering membrane packages by using a clamp, then, enabling liquid to be filtered to enter the liquid inlet unit to fill a liquid inlet flow channel, then, filtering the liquid through a filtering layer on the filtering unit to form penetrating liquid, entering the filtering liquid flow channel in the filtering unit, discharging the penetrating liquid out of the membrane package through the filtering liquid flow channel, and forming a residual solution when part of the liquid to be filtered which is not filtered by the filtering layer exists in a tangential flow filtering mode, and then, flowing out from the other end of the liquid inlet flow channel; in the dead-end filtration mode, all of the filtered liquid is filtered through the filter layer to form a permeate.

In the invention, the filtering layer adopts a cellulose filtering membrane, wherein the cellulose filtering membrane comprises a base material layer, a supporting layer and a filtering membrane layer, wherein the base material layer comprises fibers which are interwoven with one another and form a net structure, so that the supporting layer can completely or partially permeate into the base material layer and is mutually combined with the base material layer, thereby endowing the cellulose filtering membrane with higher strength, and the filtering membrane layer and the supporting layer are mutually combined and mainly play a role in filtering and separating.

The invention relates to a group which discovers that a cellulose filter layer is likely to generate surface damage during preparation when a membrane package is used for filtration, and the cellulose filter layer is also likely to generate a phenomenon that a cellulose filter layer in the membrane package is easy to damage after the membrane package is used or repeatedly used for many times, so that the failure of filtration is easily caused.

Further, the ratio of the first surface single-filament area to the first surface area is S11; the ratio of the first surface doubling area to the first surface area is S12; and S11: S12 is 1-10.

In the invention, the ratio of the first surface single-filament area to the first surface area is S11, the ratio of the first surface doubling area to the first surface area is S12, and when S11: S12 is limited within a range of 1-10, the membrane can be prevented from being damaged more when being pressed, if the ratio of S11: S12 is too high and is higher than the limited range, the single-filament area is too much and the doubling area is too little, so that the cellulose filtering membrane is easy to damage, and if the ratio of S11: S12 is too low and is lower than the limited range, the doubling area is too much and the single-filament area is too little and the area of surface leakage pores is easy to be too little, so that the cellulose filtering membrane supporting layer cannot better permeate into the substrate layer, and the bonding strength between the substrate layer and the supporting layer is easy to reduce.

Further, the single silk area accounts for 30-70% of the first surface area, and the doubling area accounts for 7-30% of the first surface area, S11.

The ratio of the single-thread area to the first surface area is limited, wherein the single-thread area is too high, so that the cellulose filtering membrane is easy to break, and the single-thread area is too low, so that the bonding strength between the substrate layer and the supporting layer is easy to reduce; the doubling area is too small, the surface is relatively uneven, the cellulose filtering membrane is easy to break, the doubling area is too large, the cellulose filtering membrane supporting layer cannot penetrate into the base material layer well, and the bonding strength is easy to reduce.

Further, the distribution density of the fiber ends in the single silk region is not more than 10 fibers/mm ² 。

The fiber end part of the single-thread area is easier to warp, so that the cellulose filtering membrane is easy to break in use, and the distribution density of the fiber end part in the single-thread area is limited to 10/mm ² Within the range, the occurrence of the rupture phenomenon of the cellulose filtration membrane can be reduced.

Further, the diameter of the fibers of the base material layer is 10-90 μm.

The fibers are too small to provide the required strength, while the fibers are too large in diameter, which easily causes the fibers in the single-filament area to arch or the raised part of the end part to easily pierce through the filter membrane layer, resulting in the damage of the filtering performance.

Further, the first surface roughness is 8-45 μm.

The first surface roughness is too high, so that the cellulose filtering membrane is easy to damage, the roughness of the first surface is too low, the surface is too smooth, a gap along the plane direction is lacked, the cellulose membrane casting solution cannot be well combined with the base material layer when being coated, and finally the combination effect between the supporting layer and the base material layer is reduced.

Further, the first surface tension is 28-45mN/m.

Because the doubling area exists on the first surface, and the fibers of the doubling area are directly bonded with each other, and the number of pores is small, compared with the single-fiber area, the existence of the doubling area can prevent the cellulose membrane casting solution from permeating into the substrate layer, so that the binding property between the substrate layer and the supporting layer is reduced, therefore, when the first surface tension is within 28-45mN/m, the direct affinity between the first surface and the cellulose membrane casting solution is relatively good, the membrane casting solution can more easily permeate into the substrate layer, the binding property between the substrate layer and the supporting layer is increased, the first surface tension can be determined by selecting different surface tension materials, and can also be changed by modifying in the prior art and other ways.

Furthermore, the thickness ratio between the substrate layer and the support layer is 1.8-3:1.

Further, the thickness of the substrate layer is 160-190 μm, and the thickness of the support layer is 65-95 μm.

The thickness and the ratio of the thickness of the base material layer to the thickness of the supporting layer are limited, wherein if the thickness of the base material layer is too large, protein is easy to adhere to the too thick supporting layer during filtering, so that the overall filtering performance is reduced, meanwhile, the thickness of the base material layer is too thick, the overall thickness of the cellulose filtering membrane is increased, the thickness of the filtering membrane is also increased easily, a good adaptive filtering process cannot be performed, base materials are wasted, and the cost is increased; and if the substrate layer undersize, the substrate layer can't play good supporting role, and the whole easy fold of cellulose filtration membrane leads to the destruction of surface pore structure. If the thickness of the supporting layer is too small, the supporting layer and the base material layer can be easily combined well, and the thickness of the supporting layer is too large, so that the flow rate of the whole cellulose filtering membrane is easily influenced.

Further, the aperture of the first surface is 55-110 μm.

The aperture of the first surface is limited in the range, and the casting solution can better penetrate to increase the combination between the supporting layer and the base material layer.

Further, the second surface comprises a single fiber area where single fibers are arranged and a doubling area where at least two fibers are combined and arranged or are interwoven with each other;

the second surface single-filament area accounts for the area ratio of the second surface S21;

the ratio of the second surface doubling area to the second surface area is S22;

and S21 and S22 are 5-90.

Further, the ratio S21 of the second surface single-thread region to the second surface area is 25-80%; the ratio S22 of the second surface doubling area to the second surface area is 5-40%.

Further, the ratio of the first surface doubling area to the first surface area S12 and the ratio of the second surface doubling area to the second surface area S22 is 2-8:1.

The ratio of the area of the second surface single-filament area to the area of the second surface and the ratio between the area of the second surface single-filament area and the area of the combined filament area to the area of the second surface are further limited, and the second surface is a filtrate transmission surface and is not in direct contact with the supporting layer, so that the influence of the surface roughness on the cellulose filtering membrane is not required to be considered, but the ratio of the area of the second surface single-filament area to the area of the combined filament area to the area of the second surface is also required to be limited in the preparation method, if the area of the combined filament area is too large, the fluid is easily blocked, the single-filament area has higher proportion of fiber arching, the degree of gaps among the fibers is higher, when the membrane is extruded, more compression spaces can be given to the substrate layer, more compression is caused to occur on the second surface, the compression influence of the first surface is reduced, and the damage of the cellulose filtering membrane is reduced; if the doubling area is too small, the bonding strength between fibers is weak, and the fibers are easy to fall off, so that the quality of the filtrate is affected.

Further, the second surface roughness is 5-60 μm.

The second surface roughness is higher than the first surface, so that the supporting layer is endowed with more compressible space, and the compressible thickness of the supporting layer is more concentrated on the side of the second surface, so that the cellulose membrane can be prevented from being damaged.

Further, the diffusion flow of the filtration membrane package is 0.5-50mL/min @15psi.

Furthermore, the base material layer fiber material comprises one or more of PET, PP and PE.

Further, the base material layer fiber is of a skin-core structure.

Further, the melting point of the skin layer in the base material layer fiber is lower than that of the core layer.

The invention can adopt the fiber with the skin-core structure, wherein the melting point of the skin layer structure is lower than that of the core layer, so that the skin layer is easier to melt and bond when in processing, the fiber is easier to form a doubling area, the core layer can not be easily melted when the skin layer is melted and bonded, good strength can be kept, and the situation that the fiber is completely melted and bonded to cause too many doubling areas and further cause that the base material layer cannot be easily penetrated by the casting solution when the cellulose filter membrane is prepared, and the bonding strength of the base material layer and the supporting layer is too low can be avoided.

Further, the ratio of the skin layer thickness to the core layer thickness is 1:1-6.

Further, the thickness of the skin layer is 3-40 μm, and the thickness of the core layer is 7-75 μm.

In the invention, the thicknesses of the skin layer and the core layer are controlled within the ranges, so that the base material layer can form a doubling area better, and the doubling area is not caused too much or too little.

Furthermore, the tensile strength of the fibers of the base material layer is 10-55N/mm.

A method of making a filtration membrane package comprising the steps of:

s1: taking non-woven fabric as primary fabric;

s2: calendaring the surface of the primary fabric to prepare a substrate layer;

s3: preparing a cellulose membrane casting solution, and uniformly covering the cellulose membrane casting solution on the first surface of the base material layer;

s4: and (3) carrying out phase separation in a coagulating bath to form a cellulose membrane, and then preparing the cellulose filtering membrane.

S5: a cellulose filtering membrane is used as a filtering layer and forms a filtering unit together with a filtering screen, and the liquid inlet unit and the filtering unit are alternately stacked to form the filtering membrane pack.

When the filtering membrane package is prepared, firstly, non-woven fabrics are selected as primary fabrics, then, the surfaces of the primary fabrics are subjected to calendaring, the proportion of a surface doubling area is increased, the smoothness degree of the surface doubling area is improved, the smoothness of the first surface is increased, fibers can be prevented from being arched and the fibers can be prevented from being punctured by the end portion being raised, the fiber can be prevented from falling off by the second surface calendaring, the prepared cellulose membrane casting solution is covered on the first surface of a base material layer, the base material layer is placed in a coagulating bath for phase separation to prepare a cellulose filtering membrane, finally, the cellulose filtering membrane is used as a filtering layer and a filtering screen to form a filtering unit, and a liquid inlet unit and the filtering unit are alternately stacked to form the filtering membrane package, wherein the membrane package forming method can be based on the prior art, for example, the method disclosed in US7097800, US 7264724.

Further, the calendering pressure in the step S2 is 0.1-6MPa.

Further, the calendering temperature in the step S2 is 140-190 ℃.

According to the invention, the pressure and the calendering temperature in the calendering process are controlled, so that the phenomena of arching and end tilting of surface fibers are reduced, and better flatness can be obtained.

Further, the viscosity of the cellulose casting solution in the step S3 is 11000-180000 cpa.

The viscosity of the casting solution is further limited, and within the range, the casting solution can well permeate into the first surface with a relatively high doubling area, and simultaneously can flatten the fiber arching or end tilting part of the single-filament area by using the viscosity of the casting solution, so that the casting solution cannot well form a film, the flattening effect is poor, the viscosity is too high, the casting solution cannot well permeate into the substrate layer, and the bonding capability of the substrate layer and the supporting layer is poor after the film is formed.

Further, the coagulating bath in the step S4 comprises deionized water, the phase separation temperature is 20-30 ℃, and the phase separation time is less than 1min.

Further, the cellulose membrane casting solution in the step S3 is a CA membrane casting solution, and after phase splitting in the step S4, hydrolysis is carried out in an alkaline solution, and finally crosslinking is carried out in a water-soluble crosslinking agent, so as to obtain the cellulose filtration membrane.

Further, the cross-linking agent in the step S4 comprises one or more of epichlorohydrin, glyoxal and glutaraldehyde; the concentration of the cross-linking agent is 3-45wt%; the crosslinking is carried out at 30-75 ℃ for 0.1-110h.

According to the invention, the first surface of the combination of the substrate layer and the support layer comprises the single-filament area and the doubling area, and the areas of the single-filament area and the doubling area are limited, wherein the single-filament area is an area where single fibers on the surface are distributed, the single fibers in the single-filament area can be better and more inserted into the support layer, so that more effects of combination with the support layer are achieved, the combination effect between the substrate layer and the support layer is better, the fibers in the doubling area are combined with each other, the surface is smoother and smoother, the cellulose is not easy to damage even if being subjected to extrusion force, the repeated use stability of the membrane filtration membrane is increased, and the service life of the filtration membrane is prolonged.

Drawings

The invention will be further described with reference to the accompanying drawings in which:

FIG. 1 is an SEM image of a first surface of a substrate layer of example 1-1 of the present invention;

FIG. 2 is an SEM image of a second surface of a substrate layer according to example 1-1 of the present invention;

FIG. 3 is a SEM image of a cross-section of a substrate layer of example 1-1;

FIG. 4 is a sectional SEM photograph of the substrate layer of example 1-2;

FIG. 5 is a schematic view of a membrane-pack diffusion flow test apparatus according to the present invention;

FIG. 6 is a SEM image of a cross section of a cellulose filtration membrane of comparative example 1 of the present invention;

FIG. 7 is a SEM photograph of the surface of a cellulose filtration membrane of comparative example 1 of the present invention.

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.

Example 1-1:

a method of making a filtration membrane package comprising the steps of:

s1, taking a sheath-core structure fiber with a PP (polypropylene) core layer and a PE (polyethylene) skin layer as a primary fabric;

s2: calendering the primary fabric at the calendering pressure of 0.8MPa, the first surface calendering temperature of 170 ℃ and the second surface calendering temperature of 150 ℃ to prepare a substrate layer;

s3: preparing a cellulose membrane casting solution with the viscosity of 19000 cpa. sCA, and uniformly covering the cellulose membrane casting solution on the first surface of the substrate layer;

s4: carrying out phase separation in coagulation bath deionized water, wherein the phase separation temperature is 25 ℃, the phase separation time is 45s, after a cellulose membrane is formed, placing the cellulose membrane in 0.01mol/L sodium hydroxide solution for hydrolysis at 50 ℃ for 20min, the hydrolysis temperature is controlled at 40 ℃, the time is controlled at 300min, and finally placing the cellulose membrane in a water-soluble cross-linking agent, wherein the concentration of the cross-linking agent is 25wt%; the crosslinking is carried out for 80 hours at 45 ℃ to prepare the regenerated cellulose filtering membrane;

s5: a cellulose filtering membrane is used as a filtering layer and forms a filtering unit together with a filtering screen, and the liquid inlet unit and the filtering unit are alternately stacked to form a filtering membrane pack;

wherein, the ratio S11 of the first surface single-filament area of the substrate layer to the first surface area is 39%, the ratio S12 of the first surface doubling area to the first surface area is 22%, and the fiber end distribution density in the first surface single-filament area is 2.5/mm ² The first surface roughness is 21 mu m, the first surface tension is 33mN/m, the ratio S21 of the second surface single silk area to the second surface area is 42%, the ratio S22 of the second surface doubling area to the second surface area is 16%, and the second surface roughness is 28 mu m; the second surface tension is 33mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 165 microns, the thickness of the supporting layer is 80 microns, the depth of the supporting layer penetrating into the base material layer is 39 microns, the aperture of the first surface is 80 microns, and the tensile strength of the base material layer fiber is 24N/mm.

The first surface of the supporting layer is shown in fig. 1, in the figure, the single-filament area is an arrangement area of single fibers and comprises an end part of the single-filament area, and the doubling area is an area in which at least two fibers are combined and arranged or are interwoven.

The second surface of the supporting layer is shown in fig. 2, in the figure, the single fiber area is a single fiber arrangement area, and the doubling area is an area where at least two fibers are combined and arranged or are interwoven.

The supporting layer is shown in fig. 3, in which the lower surface is a first surface, the upper surface is a second surface, and the first surface has a multi-fiber fusion bonding structure in the cross section, which is a doubling area.

Examples 1 to 2:

a method of making a filtration membrane package comprising the steps of:

s2: calendering the primary fabric at a calendering pressure of 1MPa and a second calendering temperature of 165 ℃ to prepare a substrate layer;

s3: preparing a cellulose membrane casting solution with the viscosity of 23000 cpa. sCA, and uniformly covering the cellulose membrane casting solution on the first surface of the base material layer;

s4: performing phase separation in coagulation bath deionized water at 20 ℃ for 45s to form a cellulose membrane, hydrolyzing in 0.03mol/L sodium hydroxide solution at 50 ℃ for 20min, controlling the hydrolysis temperature at 50 ℃ and the hydrolysis time at 100min, and finally crosslinking in a water-soluble crosslinking agent which is epichlorohydrin, wherein the concentration of the crosslinking agent is 15wt%; the crosslinking is to react for 90 hours at 65 ℃ to prepare a regenerated cellulose filtering membrane;

wherein, the ratio S11 of the first surface single-filament area of the substrate layer to the first surface area is 68%, the ratio S12 of the first surface doubling area to the first surface area is 9%, and the fiber end distribution density in the first surface single-filament area is 7.1/mm ² The first surface roughness is 38 mu m, the first surface tension is 31mN/m, the ratio S21 of the second surface single silk area to the second surface area is 39%, the ratio S22 of the second surface doubling area to the second surface area is 23%, and the second surface roughness is 21 mu m; the second surface tension is 31mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 4, the thickness of the base material layer is 170 microns, the thickness of the support layer is 75 microns, the depth of the support layer penetrating into the base material layer is 50 microns, the aperture of the first surface is 74 microns, and the tensile strength of the base material layer fiber is 18N/mm.

The supporting layer is shown in fig. 4, in which the lower surface is a first surface, the upper surface is a second surface, and the first surface has a multi-fiber fusion bonding structure in the cross section, which is a doubling area.

Examples 1 to 3:

a method of making a filtration membrane package comprising the steps of:

s1, taking a sheath-core structure fiber with a PE core layer and a PP skin layer as a primary fabric;

s2: performing calendaring on the primary fabric, wherein the calendaring pressure is 1.3MPa, and the first surface calendaring temperature is 165 ℃ to prepare a substrate layer;

s3: preparing a cellulose membrane casting solution with the viscosity of 54000 cpa. sCA, and uniformly covering the cellulose membrane casting solution on the first surface of the base material layer;

s4: carrying out phase separation in coagulation bath deionized water, wherein the phase separation temperature is 30 ℃, the phase separation time is 35s, after a cellulose membrane is formed, placing the cellulose membrane in 0.1 mol/L sodium hydroxide solution for hydrolysis at 50 ℃ for 20min, the hydrolysis temperature is controlled at 40 ℃, the time is controlled at 50min, and finally placing the cellulose membrane in water-soluble cross-linking agent for cross-linking with glyoxal, wherein the concentration of the cross-linking agent is 40wt%; the crosslinking is carried out for 110 hours at 30 ℃ to prepare the regenerated cellulose filtering membrane;

wherein, the ratio S11 of the single-filament area on the first surface of the substrate layer to the first surface area is 31 percent, the ratio S12 of the doubling area on the first surface to the first surface area is 28 percent, and the distribution density of the fiber end parts in the single-filament area on the first surface is 1.8/mm ² The first surface roughness is 22 mu m, the first surface tension is 28mN/m, the ratio S21 of the second surface single silk area to the second surface area is 76%, the ratio S22 of the second surface doubling area to the second surface area is 7%, and the second surface roughness is 49 mu m; the second surface tension is 28mN/m; the prepared base material layer has the fiber diameter of 35-45 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 1.9, the thickness of the base material layer is 187 microns, the thickness of the support layer is 77 microns, the depth of the support layer penetrating into the base material layer is 45 microns, the aperture of the first surface is 88 microns, and the tensile strength of the base material layer fiber is 27N/mm.

Examples 1 to 4:

a method of making a filtration membrane package comprising the steps of:

s1, taking a sheath-core structure fiber with a PET core layer and a PE skin layer as a primary fabric;

s2: calendaring the primary fabric, wherein the calendaring pressure is 0.9MPa, the first surface calendaring temperature is 195 ℃, and the second surface calendaring temperature is 170 ℃, so as to prepare a substrate layer;

s3: preparing a cellulose membrane casting solution with the viscosity of 85000 cpa. sCA, and uniformly covering the cellulose membrane casting solution on the first surface of the base material layer;

s4: carrying out phase splitting in coagulation bath deionized water, wherein the phase splitting temperature is 25 ℃, and the phase splitting time is 40s, so as to prepare a cellulose acetate filtering membrane;

wherein, the ratio S11 of the single-filament area on the first surface of the substrate layer to the first surface area is 47%, the ratio S12 of the doubling area on the first surface to the first surface area is 21%, and the fiber end distribution density in the single-filament area on the first surface is 3.2/mm ² The first surface roughness is 18 mu m, the first surface tension is 27mN/m, the ratio S21 of the second surface single filament area to the second surface area is 28%, the ratio S22 of the second surface doubling area to the second surface area is 32%, and the second surface roughness is 20 mu m; the second surface tension is 27mN/m; the prepared base material layer has the fiber diameter of 55-75 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 1, the thickness of the base material layer is 190 microns, the thickness of the supporting layer is 78 microns, the depth of the supporting layer penetrating into the base material layer is 35 microns, the aperture of the first surface is 93 microns, and the tensile strength of the base material layer fiber is 20N/mm.

Examples 1 to 5:

a method of making a filtration membrane package comprising the steps of:

s2: calendering the primary fabric at the calendering pressure of 0.3MPa, the first surface calendering temperature of 190 ℃ and the second surface calendering temperature of 190 ℃ to prepare a substrate layer;

s3: preparing a cellulose membrane casting solution with the viscosity of 175000 cpa. sCA, and uniformly covering the cellulose membrane casting solution on the first surface of the base material layer;

s4: carrying out phase splitting in coagulation bath deionized water at the phase splitting temperature of 25 ℃ for 45s to form a cellulose membrane, and then preparing to obtain a cellulose acetate filtering membrane;

wherein, the ratio S11 of the single-filament area on the first surface of the substrate layer to the first surface area is 43 percent, the ratio S12 of the doubling area on the first surface to the first surface area is 24 percent, and the distribution density of the fiber end parts in the single-filament area on the first surface is 4.2 pieces/mm ² The first surface roughness is 23 mu m, the first surface tension is 32mN/m, the ratio S21 of the second surface single filament area to the second surface area is 42%, the ratio S22 of the second surface doubling area to the second surface area is 27%, and the second surface roughness is 35 mu m; the second surface tension is 32mN/m; the prepared base material layer has the fiber diameter of 65-85 micrometers, the ratio of the thickness of the skin layer to the thickness of the core layer is 6, the thickness of the base material layer is 164 micrometers, the thickness of the support layer is 85 micrometers, the depth of the support layer penetrating into the base material layer is 42 micrometers, the aperture of the first surface is 42 micrometers, and the tensile strength of the base material layer fiber is 24N/mm.

Example 2-1:

a method of making a filtration membrane package comprising the steps of:

s3: preparing a cellulose membrane casting solution with the viscosity of 19000 cpa. sCA, and uniformly covering the cellulose membrane casting solution on the first surface of the base material layer;

s4: carrying out phase separation in coagulation bath deionized water, wherein the phase separation temperature is 25 ℃, the phase separation time is 45s, after a cellulose membrane is formed, placing the cellulose membrane in 0.01mol/L sodium hydroxide solution for hydrolysis at 50 ℃ for 20min, the hydrolysis temperature is controlled at 40 ℃, the time is controlled at 300min, and finally placing the cellulose membrane in a water-soluble cross-linking agent, wherein the concentration of the cross-linking agent is 25wt%; crosslinking is carried out for reacting for 80 hours at the temperature of 45 ℃ to prepare a regenerated cellulose filtering membrane;

wherein, the ratio S11 of the single-filament area on the first surface of the substrate layer to the first surface area is 39%, the ratio S12 of the doubling area on the first surface to the first surface area is 22%, and the fiber end distribution density in the single-filament area on the first surface is 2.5/mm ² The first surface roughness is 21 mu m, the first surface tension is 21mN/m, the ratio S21 of the second surface single filament area to the second surface area is 42%, the ratio S22 of the second surface doubling area to the second surface area is 16%, and the second surface roughness is 28 mu m; the second surface tension is 21mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 165 microns, the thickness of the supporting layer is 80 microns, the depth of the supporting layer penetrating into the base material layer is 25 microns, the aperture of the first surface is 80 microns, and the tensile strength of the base material layer fiber is 24N/mm.

Example 2-2:

a method of making a filtration membrane package comprising the steps of:

s4: carrying out phase separation in coagulation bath deionized water, wherein the phase separation temperature is 25 ℃, the phase separation time is 45s, after a cellulose membrane is formed, placing the cellulose membrane in 0.02mol/L sodium hydroxide solution for hydrolysis for 30min at 50 ℃, the hydrolysis temperature is controlled at 40 ℃, the time is controlled at 300min, and finally placing the cellulose membrane in a water-soluble cross-linking agent, wherein the concentration of the cross-linking agent is 35wt%; the crosslinking is carried out for 20 hours at 55 ℃ to prepare the regenerated cellulose filtering membrane;

wherein, the ratio S11 of the first surface single-filament area of the substrate layer to the first surface area is 39%, the ratio S12 of the first surface doubling area to the first surface area is 22%, and the fiber end distribution density in the first surface single-filament area is 2.5/mm ² The first surface roughness is 21 mu m, the first surface tension is 23mN/m, the ratio S21 of the second surface single filament area to the second surface area is 42%, the ratio S22 of the second surface doubling area to the second surface area is 16%, and the second surface roughness is 28 mu m; the second surface tension is 23mN/m; the diameter of the prepared base material layer fiber is 15-25 μm, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 165 μm, the thickness of the support layer is 80 μm, the depth of the support layer penetrating into the base material layer is 23 μm, the aperture of the first surface is 80 μm, and the tensile strength of the base material layer fiber is 24N/mm.

Examples 2 to 3:

a method of making a filtration membrane package comprising the steps of:

s4: carrying out phase separation in coagulation bath deionized water, wherein the phase separation temperature is 25 ℃, the phase separation time is 45s, after a cellulose membrane is formed, putting the cellulose membrane into 0.01mol/L sodium hydroxide solution for hydrolysis for 40min at the temperature of 60 ℃, the hydrolysis temperature is controlled at 40 ℃, the time is controlled at 300min, and finally putting the cellulose membrane into a water-soluble cross-linking agent for cross-linking with epichlorohydrin, wherein the concentration of the cross-linking agent is 40wt%; crosslinking is carried out for 30 hours at 60 ℃ to prepare a regenerated cellulose filtering membrane;

wherein, the ratio S11 of the single-filament area on the first surface of the substrate layer to the first surface area is 39%, the ratio S12 of the doubling area on the first surface to the first surface area is 22%, and the fiber end distribution density in the single-filament area on the first surface is 2.5/mm ² The first surface roughness is 21 mu m, the first surface tension is 49mN/m, the ratio S21 of the second surface single filament area to the second surface area is 42%, the ratio S22 of the second surface doubling area to the second surface area is 16%, and the second surface roughness is 28 mu m; the second surface tension is 49mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 165 microns, the thickness of the supporting layer is 80 microns, the depth of the supporting layer penetrating into the base material layer is 21 microns, the aperture of the first surface is 80 microns, and the tensile strength of the base material layer fiber is 24N/mm.

Examples 2 to 4:

a method of making a filtration membrane package comprising the steps of:

wherein, the ratio S11 of the single-filament area on the first surface of the substrate layer to the first surface area is 39%, the ratio S12 of the doubling area on the first surface to the first surface area is 22%, and the fiber end distribution density in the single-filament area on the first surface is 2.5/mm ² The first surface roughness is 21 mu m, the first surface tension is 67mN/m, the ratio S21 of the second surface single filament area to the second surface area is 42%, the ratio S22 of the second surface doubling area to the second surface area is 16%, and the second surface roughness is 28 mu m; the second surface tension is 67mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 165 microns, the thickness of the supporting layer is 80 microns, the depth of the supporting layer penetrating into the base material layer is 26 microns, the aperture of the first surface is 80 microns, and the tensile strength of the base material layer fiber is 24N/mm.

Example 3-1:

a method of making a filtration membrane package comprising the steps of:

s3: preparing a cellulose membrane casting solution with the viscosity of 21000 cpa. sCA, and uniformly covering the cellulose membrane casting solution on the first surface of the base material layer;

wherein, the ratio S11 of the single-filament area on the first surface of the substrate layer to the first surface area is 23%, the ratio S12 of the doubling area on the first surface to the first surface area is 35%, and the fiber end distribution density in the single-filament area on the first surface is 2.7/mm ² The first surface roughness is 33 mu m, the first surface tension is 33mN/m, the ratio S21 of the second surface single filament area to the second surface area is 27%, the ratio S22 of the second surface doubling area to the second surface area is 42%, and the second surface roughness is 12 mu m; the second surface tension is 33mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 165 microns, the thickness of the supporting layer is 80 microns, the depth of the supporting layer penetrating into the base material layer is 37 microns, the aperture of the first surface is 83 microns, and the tensile strength of the base material layer fiber is 25N/mm.

Example 3-2:

a method of making a filtration membrane package comprising the steps of:

s3: preparing a cellulose membrane casting solution with the viscosity of 25000 cpa. sCA, and uniformly covering the cellulose membrane casting solution on the first surface of the base material layer;

s4: carrying out phase separation in coagulation bath deionized water, wherein the phase separation temperature is 25 ℃, the phase separation time is 45s, after a cellulose membrane is formed, placing the cellulose membrane in 0.01mol/L sodium hydroxide solution for hydrolysis at 50 ℃ for 20min, the hydrolysis temperature is controlled at 40 ℃, the time is controlled at 300min, and finally placing the cellulose membrane in a water-soluble cross-linking agent, wherein the concentration of the cross-linking agent is 35wt%; the crosslinking is carried out for 20 hours at 55 ℃ to prepare the regenerated cellulose filtering membrane;

s5: a cellulose filtering membrane is used as a filtering layer and forms a filtering unit with a filtering screen, and the liquid inlet unit and the filtering unit are alternately stacked to form a filtering membrane package;

wherein, the ratio S11 of the first surface single-filament area of the substrate layer to the first surface area is 37%, the ratio S12 of the first surface doubling area to the first surface area is 23%, and the fiber end distribution density in the first surface single-filament area is 2.7/mm ² The first surface roughness is 35 mu m, the first surface tension is 33mN/m, the ratio S21 of the second surface single filament area to the second surface area is 15%, the ratio S22 of the second surface doubling area to the second surface area is 48%, and the second surface roughness is 12 mu m; the second surface tension is 33mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 165 microns, the thickness of the supporting layer is 78 microns, the depth of the supporting layer penetrating into the base material layer is 40 microns, the aperture of the first surface is 85 microns, and the tensile strength of the base material layer fiber is 22N/mm.

Examples 3 to 3:

a method of making a filtration membrane package comprising the steps of:

s3: preparing a cellulose membrane casting solution with the viscosity of 11000 cpa. sCA, and uniformly covering the cellulose membrane casting solution on the first surface of the base material layer;

s4: carrying out phase separation in coagulation bath deionized water, wherein the phase separation temperature is 25 ℃, the phase separation time is 45s, after a cellulose membrane is formed, placing the cellulose membrane in 0.01mol/L sodium hydroxide solution for hydrolysis at 50 ℃ for 20min, the hydrolysis temperature is controlled at 40 ℃, the time is controlled at 300min, and finally placing the cellulose membrane in a water-soluble cross-linking agent, namely epichlorohydrin for cross-linking, wherein the concentration of the cross-linking agent is 30wt%; the crosslinking is carried out for 70 hours at 40 ℃ to prepare the regenerated cellulose filtering membrane;

wherein the ratio S11 of the single-thread region on the first surface of the substrate layer to the first surface area is 39 percent, the second surfaceThe ratio S12 of the first surface area to the surface doubling area is 21%, and the fiber end distribution density in the first surface single-filament area is 2.6 pieces/mm ² The first surface roughness is 38 mu m, the first surface tension is 33mN/m, the ratio S21 of the second surface single filament area to the second surface area is 12%, the ratio S22 of the second surface doubling area to the second surface area is 48%, and the second surface roughness is 17 mu m; the second surface tension is 33mN/m; the prepared base material layer has the fiber diameter of 20-30 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 165 microns, the thickness of the support layer is 92 microns, the depth of the support layer penetrating into the base material layer is 37 microns, the aperture of the first surface is 82 microns, and the tensile strength of the base material layer fiber is 20N/mm.

Examples 3 to 4:

a method of making a filtration membrane package comprising the steps of:

s3: preparing a cellulose membrane casting solution with the viscosity of 55000 cpa. sCA, and uniformly covering the cellulose membrane casting solution on the first surface of the base material layer;

s4: carrying out phase separation in coagulation bath deionized water, wherein the phase separation temperature is 25 ℃, the phase separation time is 45s, after a cellulose membrane is formed, placing the cellulose membrane in 0.01mol/L sodium hydroxide solution for hydrolysis at 50 ℃ for 20min, the hydrolysis temperature is controlled at 40 ℃, the time is controlled at 300min, and finally placing the cellulose membrane in a water-soluble cross-linking agent, namely epichlorohydrin for cross-linking, wherein the concentration of the cross-linking agent is 20wt%; the crosslinking is to react for 70 hours at 35 ℃ to prepare a regenerated cellulose filtering membrane;

wherein, the ratio S11 of the single-filament area on the first surface of the substrate layer to the first surface area is 30%, the ratio S12 of the doubling area on the first surface to the first surface area is 29%, and the distribution density of the fiber end parts in the single-filament area on the first surface is 3.3/mm ² The first surface roughness is 29 mu m, the first surface tension is 28mN/m, the ratio S21 of the second surface single filament area to the second surface area is 10%, the ratio S22 of the second surface doubling area to the second surface area is 55%, and the second surface roughness is 13 mu m; the second surface tension is 28mN/m; the prepared base material layer has the fiber diameter of 20-30 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 165 microns, the thickness of the supporting layer is 80 microns, the depth of the supporting layer penetrating into the base material layer is 48 microns, the aperture of the first surface is 88 microns, and the tensile strength of the base material layer fiber is 22N/mm.

Examples 3 to 5:

a method of making a filtration membrane package comprising the steps of:

wherein, the ratio S11 of the single-filament area on the first surface of the substrate layer to the first surface area is 31 percent, the ratio S12 of the doubling area on the first surface to the first surface area is 27 percent, and the distribution density of the fiber end parts in the single-filament area on the first surface is 3.4 pieces/mm ² The first surface roughness is 29 μm, the first surface tension is 28mN/m, and the single filament region of the second surface occupies the second surfaceThe area ratio S21 is 15%, the ratio S22 of the second surface doubling area to the second surface area is 52%, and the second surface roughness is 12 μm; the second surface tension is 28mN/m; the diameter of the prepared base material layer fiber is 20-30 μm, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 165 μm, the thickness of the support layer is 80 μm, the depth of the support layer penetrating into the base material layer is 45 μm, the aperture of the first surface is 90 μm, and the tensile strength of the base material layer fiber is 27N/mm.

Examples 3 to 6:

a method of making a filtration membrane package comprising the steps of:

s2: calendaring the primary fabric, wherein the calendaring pressure is 1.3MPa, and the first surface calendaring temperature is 165 ℃, so as to prepare a substrate layer;

s3: preparing a cellulose membrane casting solution with the viscosity of 56000 cpa. sCA, and uniformly covering the cellulose membrane casting solution on the first surface of the base material layer;

s4: carrying out phase separation in coagulation bath deionized water, wherein the phase separation temperature is 25 ℃, the phase separation time is 45s, after a cellulose membrane is formed, placing the cellulose membrane in 0.01mol/L sodium hydroxide solution for hydrolysis at 50 ℃ for 20min, the hydrolysis temperature is controlled at 40 ℃, the time is controlled at 300min, and finally placing the cellulose membrane in a water-soluble cross-linking agent, wherein the concentration of the cross-linking agent is 15wt%; the crosslinking is carried out for 70 hours at 55 ℃ to prepare the regenerated cellulose filtering membrane;

wherein, the ratio S11 of the single-filament area on the first surface of the substrate layer to the first surface area is 31 percent, the ratio S12 of the doubling area on the first surface to the first surface area is 30 percent, and the distribution density of the fiber end parts in the single-filament area on the first surface is 3.2 pieces/mm ² The first surface roughness is 27 mu m, the first surface tension is 28mN/m, the ratio S21 of the second surface single filament area to the second surface area is 20%, the ratio S22 of the second surface doubling area to the second surface area is 49%, and the second surface roughness is 15 mu m; first, theThe surface tension of the two surfaces is 28mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 165 microns, the thickness of the support layer is 92 microns, the depth of the support layer penetrating into the base material layer is 44 microns, the aperture of the first surface is 80 microns, and the tensile strength of the base material layer fiber is 24N/mm.

Example 4-1:

a method of making a filtration membrane package comprising the steps of:

s2: calendaring the primary fabric, wherein the calendaring pressure is 0.6MPa, and the first surface calendaring temperature is 150 ℃, so as to prepare a substrate layer;

wherein, the ratio S11 of the first surface single-filament area of the substrate layer to the first surface area is 55%, the ratio S12 of the first surface doubling area to the first surface area is 12%, and the fiber end distribution density in the first surface single-filament area is 6.8/mm ² The first surface roughness is 39 mu m, the first surface tension is 33mN/m, the ratio S21 of the second surface single filament area to the second surface area is 65%, the ratio S22 of the second surface doubling area to the second surface area is 10%, and the second surface roughness is 46 mu m; the second surface tension is 33mN/m; the prepared base material layer has a fiber diameter of 15-25 μm and a ratio of the thickness of the skin layer to the thickness of the core layerAnd 3, the thickness of the base material layer is 170 micrometers, the thickness of the support layer is 78 micrometers, the depth of the support layer penetrating into the base material layer is 13 micrometers, the aperture of the first surface is 100 micrometers, and the tensile strength of the base material layer fiber is 28N/mm.

Example 4-2:

a method of making a filtration membrane package comprising the steps of:

s2: performing calendaring on the primary fabric, wherein the calendaring pressure is 0.6MPa, and the first surface calendaring temperature is 150 ℃, so as to prepare a substrate layer;

s4: carrying out phase separation in coagulation bath deionized water, wherein the phase separation temperature is 25 ℃, the phase separation time is 45s, after a cellulose membrane is formed, placing the cellulose membrane in 0.01mol/L sodium hydroxide solution for hydrolysis at 50 ℃ for 20min, the hydrolysis temperature is controlled at 40 ℃, the time is controlled at 300min, and finally placing the cellulose membrane in a water-soluble cross-linking agent, wherein the concentration of the cross-linking agent is 15wt%; the crosslinking is to react for 80 hours at 55 ℃ to prepare a regenerated cellulose filtering membrane;

wherein, the ratio S11 of the single-filament area of the first surface of the substrate layer to the first surface area is 59 percent, the ratio S12 of the doubling area of the first surface to the first surface area is 14 percent, and the distribution density of the fiber end parts in the single-filament area of the first surface is 5.9/mm ² The first surface roughness is 42 mu m, the first surface tension is 33mN/m, the ratio S21 of the second surface single filament area to the second surface area is 63%, the ratio S22 of the second surface doubling area to the second surface area is 11%, and the second surface roughness is 49 mu m; the second surface tension is 33mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 170 microns, the thickness of the support layer is 78 microns, the depth of the support layer penetrating into the base material layer is 12 microns, and the first layer is a first layerThe pore diameter of the surface is 98 mu m, and the tensile strength of the base material layer fiber is 26N/mm.

Examples 4 to 3:

a method of making a filtration membrane package comprising the steps of:

wherein, the ratio S11 of the first surface single-filament area of the substrate layer to the first surface area is 57%, the ratio S12 of the first surface doubling area to the first surface area is 15%, and the fiber end distribution density in the first surface single-filament area is 7.2/mm ² The first surface roughness is 40 mu m, the first surface tension is 33mN/m, the ratio S21 of the second surface single filament area to the second surface area is 67%, the ratio S22 of the second surface doubling area to the second surface area is 11%, and the second surface roughness is 52 mu m; the second surface tension is 33mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 170 microns, the thickness of the support layer is 75 microns, the depth of the support layer penetrating into the base material layer is 18 microns, the aperture of the first surface is 95 microns, and the tensile strength of the base material layer fiber is 22N/mm.

Examples 4 to 4:

a method of making a filtration membrane package comprising the steps of:

s2: calendaring the primary fabric, wherein the calendaring pressure is 0.8MPa, and the first surface calendaring temperature is 170 ℃, so as to prepare a substrate layer;

wherein, the ratio S11 of the single-filament area on the first surface of the substrate layer to the first surface area is 38%, the ratio S12 of the doubling area on the first surface to the first surface area is 35%, and the fiber end distribution density in the single-filament area on the first surface is 0.2/mm ² The first surface roughness is 17 mu m, the first surface tension is 33mN/m, the ratio S21 of the second surface single filament area to the second surface area is 52%, the ratio S22 of the second surface doubling area to the second surface area is 12%, and the second surface roughness is 48 mu m; the second surface tension is 33mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 170 microns, the thickness of the supporting layer is 78 microns, the depth of the supporting layer penetrating into the base material layer is 43 microns, the aperture of the first surface is 75 microns, and the tensile strength of the base material layer fiber is 25N/mm.

Examples 4 to 5:

a method of making a filtration membrane package comprising the steps of:

wherein, the ratio S11 of the single-filament area on the first surface of the substrate layer to the first surface area is 35%, the ratio S12 of the doubling area on the first surface to the first surface area is 33%, and the fiber end distribution density in the single-filament area on the first surface is 0.4/mm ² The first surface roughness is 14 mu m, the first surface tension is 33mN/m, the ratio S21 of the second surface single filament area to the second surface area is 53%, the ratio S22 of the second surface doubling area to the second surface area is 15%, and the second surface roughness is 45 mu m; the second surface tension is 33mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 170 microns, the thickness of the support layer is 82 microns, the depth of the support layer penetrating into the base material layer is 44 microns, the aperture of the first surface is 80 microns, and the tensile strength of the base material layer fiber is 26N/mm.

Comparative example 1:

a method of making a filtration membrane package comprising the steps of:

s2: performing calendaring on the primary fabric, wherein the calendaring pressure is 0.9MPa, and the second surface calendaring temperature is 165 ℃ to prepare a substrate layer;

s3: preparing a cellulose membrane casting solution with the viscosity of 58000 cpa. sCA, and uniformly covering the cellulose membrane casting solution on the first surface of the base material layer;

wherein, the ratio S11 of the single-filament area of the first surface of the substrate layer to the first surface area is 77%, the ratio S12 of the doubling area of the first surface to the first surface area is 2%, and the distribution density of the fiber end parts in the single-filament area of the first surface is 12.1/mm ² The first surface roughness is 53 mu m, the first surface tension is 33mN/m, the ratio S21 of the second surface single silk area to the second surface area is 43%, the ratio S22 of the second surface doubling area to the second surface area is 18%, and the second surface roughness is 27 mu m; the second surface tension is 33mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 170 microns, the thickness of the support layer is 74 microns, the depth of the support layer penetrating into the base material layer is 54 microns, the aperture of the first surface is 73 microns, and the tensile strength of the base material layer fiber is 28N/mm.

Comparative example 2:

a method of making a filtration membrane package comprising the steps of:

wherein, the ratio S11 of the first surface single-filament area of the substrate layer to the first surface area is 76%, the ratio S12 of the first surface doubling area to the first surface area is 5%, and the fiber end distribution density in the first surface single-filament area is 10.3/mm ² The first surface roughness is 21 mu m, the first surface tension is 33mN/m, the ratio S21 of the second surface single filament area to the second surface area is 44%, the ratio S22 of the second surface doubling area to the second surface area is 17%, and the second surface roughness is 26 mu m; the second surface tension is 33mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 170 microns, the thickness of the supporting layer is 75 microns, the depth of the supporting layer penetrating into the base material layer is 55 microns, the aperture of the first surface is 78 microns, and the tensile strength of the base material layer fiber is 25N/mm.

Comparative example 3:

a method of making a filtration membrane package comprising the steps of:

s2: calendaring the primary fabric, wherein the calendaring pressure is 0.9MPa, and the second surface calendaring temperature is 165 ℃, so as to prepare a substrate layer;

s3: preparing a cellulose casting solution with the viscosity of 58000 cpa. sCA, and uniformly covering the cellulose casting solution on the first surface of the base material layer;

wherein, the ratio S11 of the single-filament area on the first surface of the substrate layer to the first surface area is 81%, the ratio S12 of the doubling area on the first surface to the first surface area is 6%, and the fiber end distribution density in the single-filament area on the first surface is 14.2/mm ² The first surface roughness is 52 mu m, the first surface tension is 33mN/m, the ratio S21 of the second surface single filament area to the second surface area is 43%, the ratio S22 of the second surface doubling area to the second surface area is 19%, and the second surface roughness is 26 mu m; the second surface tension is 33mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 170 microns, the thickness of the supporting layer is 88 microns, the depth of the supporting layer penetrating into the base material layer is 53 microns, the aperture of the first surface is 75 microns, and the tensile strength of the base material layer fiber is 25N/mm.

Comparative example 4:

a method of making a filtration membrane package comprising the steps of:

s2: calendering the primary fabric at a calendering pressure of 2MPa, at a first surface calendering temperature of 180 ℃ and at a second surface calendering temperature of 140 ℃ to prepare a substrate layer;

wherein, the ratio S11 of the single-filament area on the first surface of the substrate layer to the first surface area is 25%, the ratio S12 of the doubling area on the first surface to the first surface area is 35%, and the fiber end distribution density in the single-filament area on the first surface is 0.3/mm ² The first surface roughness is 10 mu m, the first surface tension is 33mN/m, the ratio S21 of the second surface single filament area to the second surface area is 45%, the ratio S22 of the second surface doubling area to the second surface area is 19%, and the second surface roughness is 28 mu m; the second surface tension is 33mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 170 microns, the thickness of the supporting layer is 73 microns, the depth of the supporting layer penetrating into the base material layer is 15 microns, the aperture of the first surface is 48 microns, and the tensile strength of the base material layer fiber is 25N/mm.

Comparative example 5:

a method of making a filtration membrane package comprising the steps of:

wherein, the ratio S11 of the single-filament area on the first surface of the substrate layer to the first surface area is 27%, the ratio S12 of the doubling area on the first surface to the first surface area is 41%, and the fiber end distribution density in the single-filament area on the first surface is 0.5/mm ² The first surface roughness is 6 mu m, the first surface tension is 33mN/m, the ratio S21 of the second surface single filament area to the second surface area is 43%, the ratio S22 of the second surface doubling area to the second surface area is 22%, and the second surface roughness is 29 mu m; the second surface tension is 33mN/m; the prepared base material layer has the fiber diameter of 15-25 microns, the ratio of the thickness of the skin layer to the thickness of the core layer is 3, the thickness of the base material layer is 170 microns, the thickness of the support layer is 78 microns, the depth of the support layer penetrating into the base material layer is 13 microns, the aperture of the first surface is 45 microns, and the tensile strength of the base material layer fiber is 28N/mm.

The test method comprises the following steps:

according to the invention, after the morphology characterization of the structures of the cellulose filtering membrane and the substrate layer is carried out by using a scanning electron microscope, the fiber diameter, the single-fiber area/doubling area ratio, the fiber end distribution density in the single-fiber area and the like are measured by using computer software (such as Matlab, NIS-Elements and the like) or a manual measuring mode; in the preparation process of the cellulose filtering membrane, in the direction vertical to the thickness direction of the cellulose filtering membrane, namely the plane direction of the supporting layer, all characteristics such as fiber distribution are basically kept consistent, so that the integral level on the plane can be reflected by the fiber diameter of partial areas on the corresponding plane, the single-thread area/combined-thread area ratio and the fiber end distribution density in the single-thread area. In actual measurement, the surface of the membrane can be characterized by an electron microscope to obtain a corresponding SEM image,since the surface distribution is substantially uniform, a certain area, for example 1 μm, can be selected ² (1 μm by 1 μm) or 10mm ² (100 μm multiplied by 100 μm), and the like, wherein the specific area size is determined according to the actual situation, and then the fiber diameter, the single-fiber area/doubling area ratio and the fiber end distribution density in the single-fiber area on the area are measured by corresponding computer software or manually, so that the average value of the surface is represented; of course, the skilled person can also obtain the above parameters by other measuring means, which are only used as reference. Meanwhile, the substrate layer can also be obtained by dissolving the cellulose filter membrane with a solvent (for example, by adopting an NMMO (n-methyl-ammonium) ionic liquid or an alkali/urea system) or performing enzymolysis on cellulose, and certainly, the morphological structure characterization of the cross section of the cellulose filter membrane can also be used for deducing the structure of the surface of the substrate layer, for example, if the cross section formed on the surface has a hot-melt adhesive structure with two fibers, the surface of the substrate layer can be deduced to be used in a doubling area.

And (3) testing roughness: three surface areas of about 0.65X 0.45 mm in size were scanned (area size defined by constant 5X magnification and autofocus using a scanning microscope) over a 6X 6 mm surface area using a ContourGT-X three-dimensional optical profiler (Bruker, geman) test, taking n = 6 linear tracks (200 μm each), a profile filter: cutoff wavelength λ s = 0.8 μm, λ c = 0.08 mm, roughness was measured, and the average value was calculated.

And (3) testing the surface tension: the test is carried out by adopting a dyne test method.

The filtration membranes prepared in the examples and comparative examples are all 0.11m ² The 3K membrane package of (1) is used for carrying out a diffusion flow test, and the specific method comprises the following steps: a membrane package having a filter area of 0.11 square meters was prepared and the test unit was assembled as shown in figure 4. The air valve was closed first and the pressure regulator was set to 0bar (0 psi). Closing the feed valve and the drain valve, and opening the reflux valve and the feed-through valve; opening the air valve to remove water from the membrane feed-return lineThen slowly adjust the pressure regulator to 0.35bar (5 psi); flowing air through the system until water ceases to drain from the return conduit; closing the return valve, allowing air pressure to remove water thrown through the pipe from the permeate port, and slowly adjusting the pressure regulator to 1bar (15 psi); fill a 50mL graduated cylinder with water and invert it in a 500mL beaker with water, connect the flexible tube to the permeate-end outlet; when the bubble rate is stable, recording the corresponding time and the air quantity in the measuring cylinder; when 5-10mL of gas was collected, the corresponding time and air volume were again recorded; calculate the air diffusion rate (mL/min/@ 15 psi); the results are shown in the following table.

As can be seen from examples 1-1 to 1-5, the filter membrane package with the substrate layer parameters within the limits of the present invention still has good diffusion flow after being used many times, and the bonding performance between the support layer and the substrate layer is good.

As can be seen from examples 2-1 to 2-4, too high or too low surface tension of the first surface of the substrate layer easily causes the casting solution not to well penetrate into the support layer, and thus the bonding effect between the substrate layer and the support layer is relatively poor.

As can be seen from examples 3-1 to 3-6, when the ratio of the single-filament region on the second surface of the base material layer was too low and the ratio of the doubled-filament region was too high, the entire compressed space of the base material layer decreased, and therefore, when the filtration membrane package was used, the base material layer more easily caused the puncture of the cellulose filtration membrane, which caused the increase of the diffusion flow.

As can be seen from the comparison of the embodiments 4-1 to 4-5, compared with the situation that the single fiber is too sensitive to the calendering process, the skin-core structural fiber adopted by the substrate layer can better control the formation of the doubling area of the first surface, so that the excess is avoided on the premise of ensuring the smoothness, and the phenomenon of poor combination effect of the support layer and the substrate layer is avoided.

As can be seen from comparative examples 1 to 5, when the first surface doubling area proportion is too small and the single yarn area proportion is too large (comparative examples 1 to 3), the roughness is relatively high, and the breakage of the cellulose filtering membrane during filtering is easily caused; as shown in fig. 6 and 7, after the filtration is used, the surface structure of the membrane is damaged, so that the diffusion flow is enlarged; and when the ratio of the first surface doubling area is too large and the ratio of the single-thread area is too small (comparative examples 4 to 5), the direct bonding between the substrate layer and the support layer is relatively poor.

While the preferred embodiments of the present invention have been illustrated and described in detail, it should be understood that various changes and modifications of the invention can be effected therein by those skilled in the art after reading the above teachings of the invention. Such equivalents are intended to fall within the scope of the claims appended hereto.

Claims

1. A filter membrane package comprises a first membrane and a second membrane,

the liquid inlet unit comprises a liquid inlet screen which forms a fluid liquid inlet flow channel;

the method is characterized in that:

the support layer partially or completely penetrates into the substrate layer and is combined with the substrate layer;

the filter membrane layer is combined with the support layer;

a first surface bonded to the support layer, and a second surface through which the filtrate permeates;

the first surface comprises a single silk area with single fibers arranged and a doubling area with at least two fibers arranged in a combining way or interwoven mutually;

the ratio of the first surface single-filament area to the first surface area is S11;

the ratio of the first surface doubling area to the first surface area is S12;

s11, S12 is 1-10;

the first surface single filament area accounts for 30-70% of the first surface area S11, and the first surface doubling area accounts for 7-30% of the first surface area S12.

2. A filter membrane package according to claim 1, wherein the first surface-independent region has a fiber end distribution density of no greater than 10 fibers/mm ² 。

3. A filtration membrane package according to claim 1, wherein the substrate layer fibers have a diameter of 10-90 μm.

4. A filter membrane package according to claim 1, wherein the first surface roughness is 8-45 μ ι η.

5. A filtration membrane package according to claim 1, wherein the first surface tension is 28-45mN/m.

6. A filtration membrane package as recited in claim 1, wherein the substrate layer has a thickness of 160-190 μm, the support layer has a thickness of 65-95 μm, and the thickness ratio between the substrate layer and the support layer is 1.8-3:1.

7. A filtration membrane package according to claim 1, wherein the pore size of the first surface is 55-110 μ ι η.

8. A filtration membrane package according to claim 1, wherein the second surface comprises a single filament region in which individual fibers are arranged, a cabled region in which at least two fibers are arranged in a merged or interwoven pattern;

the second surface single-filament area accounts for the area ratio of the second surface to the second surface, and is S21;

s21, S22 is 5-90;

the ratio S21 of the single-thread area of the second surface to the area of the second surface is 25-80%; the ratio S22 of the second surface doubling area to the second surface area is 5-40%.

9. A filter membrane package according to claim 1, wherein the second surface roughness is in the range of 5-60 μ ι η.

10. The filtration membrane package of claim 1, wherein the filtration membrane package has a diffusive flow of 0.5-50mL/min @15psi.

11. A filter membrane package as recited in claim 1, wherein the base material layer comprises one or more of PET, PP, and PE.

12. A filtration membrane package as recited in claim 1, wherein the substrate layer fibers are of a sheath-core construction.

13. A filtration membrane package according to claim 12, wherein the fibers of the base layer have a sheath layer melting point lower than the core layer melting point.

14. A filter membrane package as recited in claim 12, wherein the skin layer has a thickness of 3-40 μ ι η and the core layer has a thickness of 7-75 μ ι η; the ratio of the skin thickness to the core thickness is 1:1-6.

15. A filtration membrane package as recited in claim 1, wherein the substrate layer fibers have a tensile strength of 10-55N/mm.

16. A method of making a filtration membrane package according to any one of claims 1 to 15, comprising the steps of:

s1: taking non-woven fabric as primary fabric;

s2: performing calendaring on the surface of the primary fabric to prepare a substrate layer;

s4: carrying out phase separation in a coagulating bath to form a cellulose membrane, and preparing to obtain a cellulose filtering membrane;

s5: a cellulose filtering membrane is used as a filtering layer to form a filtering liquid unit together with a filtering liquid screen, and the liquid inlet unit and the filtering liquid unit are alternately stacked to form the filtering membrane package.

17. A method of manufacturing a filter membrane package according to claim 16, wherein the calendering pressure in step S2 is 0.1-6MPa.

18. A method of making a filter membrane package according to claim 16, wherein the calendering temperature in step S2 is from 140 ℃ to 190 ℃.

19. A method of making a filtration membrane package according to claim 16, wherein the viscosity of said cellulose casting solution in step S3 is 11000-180000 cPa-S.

20. A method of making a filter membrane package according to claim 16, wherein the coagulation bath in step S4 comprises deionized water, the phase separation temperature is 20-30 ℃, and the phase separation time is less than 1min.

21. A method for preparing a filtration membrane package according to claim 16, wherein the cellulose membrane-casting solution in step S3 is a CA membrane-casting solution, and after phase separation in step S4, hydrolysis is performed in an alkaline solution, and finally crosslinking is performed in a water-soluble crosslinking agent to obtain the cellulose filtration membrane.

22. The method for preparing a filter membrane package according to claim 21, wherein the cross-linking agent in step S4 comprises one or more of epichlorohydrin, glyoxal, glutaraldehyde; the concentration of the cross-linking agent is 3-45wt%; the crosslinking is carried out at 30-75 ℃ for 0.1-110h.