Preparation method for polyester support, and polyester support prepared by using same and use thereof

Abstract

A preparation method for a polyester support, and a polyester support prepared by using same and the use thereof. The preparation method comprises the following steps: preparing a coated-surface fiber slurry and a non-coated-surface fiber slurry; preparing a coated-surface fiber layer and a non-coated-surface fiber layer; subjecting the coated-surface fiber layer to hydrophilizing antimicrobial modification; coating the non-coated-surface fiber layer with an adhesive coating composition, so as to form an intermediate bonding layer; and placing the coated-surface fiber layer, which has been subjected to hydrophilizing antimicrobial modification, onto the non-coated-surface fiber layer, on which the intermediate bonding layer is formed, and subjecting same to post-treatment, so as to form a polyester support. The polyester support has a three-layer composite structure, uniform porosity, good air permeability and tensile strength, has high bonding force with regard to a semipermeable membrane, and also has good hydrophilicity and antimicrobial properties. The polyester support can be advantageously applied to water treatment, filtration and separation.

Description

Preparation method of polyester support, polyester support prepared thereby and application thereof

[0001] Citation of Related Applications

[0002] This disclosure claims priority to invention patent application number 202310924682.4, entitled “Method for preparing polyester support, polyester support prepared thereby and application thereof,” filed in China on July 26, 2023, and the entire contents of that patent application are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a preparation method of a polyester support, a polyester support prepared thereby, and applications thereof, belonging to the field of membranes for filtration and / or separation, and more specifically, to a polyester support for composite with a semipermeable membrane for water treatment. Background Art

[0004] Semipermeable membranes, as a highly efficient filtration material, are gaining increasing attention and widespread application in fields such as seawater desalination, sewage treatment, pharmaceutical concentration, hemodialysis, and food concentration. Semipermeable membranes are composed of synthetic resins such as cellulose, polyester, polysulfone, polyamide, and fluororesins. These materials form thin membrane layers and have low bulk strength, making them difficult to operate stably and long-term within the membrane's rated operating conditions, making them impractical for standalone use. To ensure the required strength, the most common method for commercially producing semipermeable membranes is to combine them with a support material.

[0005] The production methods of supports are mainly spunbond, needlepunch, hydroentangled, and meltblown. Due to factors such as immature supporting equipment, high process technology barriers, and small market size, supports prepared by wet process account for less than 3% of the global share. However, the supports produced by wet process have a smooth surface, high porosity, low thermal shrinkage, and high strength, which can effectively guarantee the separation performance of semipermeable membranes, making them a commonly used porous support material in industrial membrane production. Polypropylene (PP) supports and polyester (PET) supports are two of the more commonly used support materials. Compared with polypropylene supports, polyester supports have higher thermal stability, longer anti-aging cycles, and better solvent resistance. Therefore, for separation membranes with higher requirements for separation accuracy and flux, polyester supports are more widely used.

[0006] The support substrate for semipermeable membranes used in water treatment must possess excellent fiber web distribution uniformity, a good microporous structure, high tensile strength, moderate polymer solution permeability, and a surface free of fuzz and macropore defects. However, membrane supports and their key raw material, low-melting-point polyester fiber, are currently monopolized by foreign companies such as Mitsubishi, Miki, and Awa Paper. Membrane supports are becoming a key link in the battle for market share in the membrane materials industry chain.

[0007] Invention patent CN102574070B discloses a non-woven fabric composed of two or more fibers of different diameters, which is used as a support for a semipermeable membrane. The invention patent emphasizes the difference between the coated surface and the uncoated surface of the support.

[0008] Invention patent CN103429327B discloses a semipermeable membrane support body composed of a multilayer structure. Through the different tensile strength aspect ratios of the multilayer structure, after heating and compounding, it is pre-bent on one side to offset the bending of the support body to the other side when heated after coating with solution. However, this method has relatively strict requirements on the tensile strength aspect ratio of the material.

[0009] Invention patent CN105040275B proposes a method for producing a substrate nonwoven fabric using three types of fibers through a wet-laid forming process. Taking advantage of the different specific gravities of the fibers, the slurry is distributed in three layers during transportation and forming, and then hot-pressed into a composite nonwoven fabric with upper, middle, and lower layers. This three-layer distribution is theoretically feasible, but in actual production, to avoid laminar flow and flocculation of the fiber slurry, the fiber slurry must be in a turbulent or slightly turbulent state during transportation and forming.

[0010] Invention patent CN103432912B discloses a composite support material for a semipermeable membrane and its manufacturing method. By introducing a foam adhesive coating layer between the coating layer and the non-coating layer, the material inhibits, to a certain extent, the penetration of the semipermeable membrane solution into the non-coated surface of the composite support material. The foam adhesive coating layer controls the tensile strength and barrier properties of the support layer by adjusting the coating amount. However, the micropore diameter reaches 100 μm, which is too large to effectively inhibit the semipermeable membrane solution from penetrating the non-woven fabric.

[0011] The structures of supports described in the prior art have shown difficulty in simultaneously suppressing the permeation of the semipermeable membrane solution and addressing the problems of curling of the coating surface and the proneness of pinholes and defects in the separation membrane layer. Furthermore, due to the smooth surface, dense molecular structure, and lack of polar functional groups in polyester fibers, supports prepared from them exhibit typical hydrophobicity, making it difficult to establish a good interfacial interaction with the polymer matrix. However, the prior art rarely discloses methods for modifying polyester supports for hydrophilicity or anti-fouling properties.

[0012] Summary of the Invention

[0013] Problems to be solved by the invention

[0014] In order to solve the above technical problems, the purpose of the present disclosure is to provide a method for preparing a polyester support, a polyester support prepared thereby, and applications thereof.

[0015] Solutions for solving problems

[0016] The inventors of the present disclosure have conducted in-depth research to achieve the above objectives and proposed the following method for preparing a polyester support, which comprises the following steps:

[0017] Prepare a coated side fiber slurry and a non-coated side fiber slurry, wherein the fiber slurry contains main fibers and hot-melt bonding fibers, the diameter of the main fibers contained in the coated side fiber slurry is smaller than the diameter of the main fibers contained in the non-coated side fiber slurry, and the diameter of the hot-melt bonding fibers contained in the coated side fiber slurry is smaller than the diameter of the hot-melt bonding fibers contained in the non-coated side fiber slurry;

[0018] preparing a coated-side fiber layer and a non-coated-side fiber layer;

[0019] The coated surface fiber layer is subjected to hydrophilic antibacterial modification, wherein the hydrophilic antibacterial modification is performed by contacting the coated surface fiber layer with a modification solution, wherein the modification solution contains a hydrophilic monomer and an antibacterial functional material;

[0020] coating an adhesive coating composition on the non-coated fiber layer to form an intermediate adhesive layer, wherein the adhesive coating composition comprises an adhesive and ultrafine short fibers;

[0021] The hydrophilic antibacterial modified coated fiber layer is placed on the non-coated fiber layer with the intermediate adhesive layer, and hot pressed to form a polyester support;

[0022] The polyester support is post-treated.

[0023] In the preparation method disclosed herein, the main fiber is at least one of polyester fiber, polypropylene fiber, polyacrylate fiber, polyurethane fiber, polyamide fiber and polyimide fiber.

[0024] The preparation method disclosed herein, wherein the hot-melt bonding fiber is at least one of a sheath-core type, a side-by-side type, a sea-island type and a pie-shaped bicomponent composite fiber.

[0025] The preparation method disclosed herein comprises the following steps: in the coated surface fiber slurry, the diameter of the main fiber is 6.0-9.0 μm, the diameter of the hot-melt bonding fiber is 8.0-11.0 μm, and the content of the main fiber is 55-90 wt%, and the content of the hot-melt bonding fiber is 10-45 wt%, based on the total weight of the fibers contained in the coated surface fiber slurry; and in the non-coated surface fiber slurry, the diameter of the main fiber is 6.0-13.0 μm, the diameter of the hot-melt bonding fiber is 8.0-14.0 μm, and the content of the main fiber is 60-95 wt%, and the content of the hot-melt bonding fiber is 5-40 wt%, based on the total weight of the fibers contained in the non-coated surface fiber slurry.

[0026] The preparation method disclosed herein, wherein the hydrophilic monomer is at least one of di(ethylene glycol) methyl ether methacrylate DEGMEMA, hydroxyethyl methacrylate HEMA, maleic anhydride, acrylamide, methacrylamide, acrylic acid and its esters, methacrylic acid and its esters, polyvinyl alcohol PVA and polyethylene glycol PEG, and the antibacterial functional material is at least one of an antibacterial functional monomer, a bactericidal nanomaterial and a natural biological molecule.

[0027] The preparation method disclosed herein, wherein the adhesive is at least one of an organic silicone adhesive, an acrylic adhesive, an acrylate adhesive and a polyurethane adhesive.

[0028] The preparation method disclosed herein, wherein the ultrafine short fibers have a diameter of 2.0-5.0 μm and a length of 3.0-6.0 mm.

[0029] In the preparation method disclosed herein, the coating surface fiber layer is pretreated to generate active groups before the hydrophilic antibacterial modification.

[0030] In the preparation method disclosed herein, the pretreatment is at least one of pre-irradiation and solution pretreatment.

[0031] The present disclosure also provides a polyester support body prepared according to the preparation method described in the present disclosure, which comprises a coating surface fiber layer, an intermediate adhesive layer and a non-coating surface fiber layer in sequence, characterized in that the coating surface fiber layer is hydrophilized and antibacterial modified, the intermediate adhesive layer contains an adhesive and ultrafine short fibers, the coating surface fiber layer and the non-coating surface fiber layer each contain a main fiber and a hot-melt bonding fiber, the diameter of the main fiber contained in the coating surface fiber layer is smaller than the diameter of the main fiber contained in the non-coating surface fiber layer, and the diameter of the hot-melt bonding fiber contained in the coating surface fiber layer is smaller than the diameter of the hot-melt bonding fiber contained in the non-coating surface fiber layer.

[0032] The polyester support described in the present disclosure, wherein the main fiber is at least one of polyester fiber, polypropylene fiber, polyacrylate fiber, polyurethane fiber, polyamide fiber and polyimide fiber.

[0033] The polyester support described in the present disclosure, wherein the hot-melt bonding fiber is at least one of a sheath-core type, a side-by-side type, a sea-island type and a pie-shaped bicomponent composite fiber.

[0034] The polyester support disclosed herein has a main fiber diameter of 6.0-9.0 μm in the coated surface fiber layer, a heat-melt adhesive fiber diameter of 8.0-11.0 μm, and a main fiber content of 55-90 wt%, and a heat-melt adhesive fiber content of 10-45 wt%, based on the total weight of the fibers contained in the coated surface fiber layer; and a main fiber diameter of 6.0-13.0 μm in the uncoated surface fiber layer, a heat-melt adhesive fiber diameter of 8.0-14.0 μm, and a main fiber content of 60-95 wt%, and a heat-melt adhesive fiber content of 5-40 wt%, based on the total weight of the fibers contained in the uncoated surface fiber layer.

[0035] The polyester support described in the present disclosure, wherein the hydrophilic antibacterial modification is carried out by contacting the coated surface fiber layer with a modification solution, the modification solution contains a hydrophilic monomer and an antibacterial functional material, the hydrophilic monomer is at least one of di(ethylene glycol) methyl ether methacrylate DEGMEMA, hydroxyethyl methacrylate HEMA, maleic anhydride, acrylamide, methacrylamide, acrylic acid and its esters, methacrylic acid and its esters, polyvinyl alcohol PVA and polyethylene glycol PEG, and the antibacterial functional material is at least one of an antibacterial functional monomer, a bactericidal nanomaterial and a natural biological molecule.

[0036] The polyester support described in the present disclosure, wherein the adhesive is at least one of an organic silicone adhesive, an acrylic adhesive, an acrylate adhesive and a polyurethane adhesive.

[0037] The polyester support described in the present disclosure, wherein the ultrafine short fibers have a diameter of 2.0-5.0 μm and a length of 3.0-6.0 mm.

[0038] The present disclosure also provides an application of a polyester support prepared according to the preparation method described in the present disclosure in water treatment.

[0039] The present disclosure also provides a use of a polyester support prepared according to the preparation method described in the present disclosure in filtration and / or separation.

[0040] Effects of the Invention

[0041] The polyester support provided by the present disclosure has a specific three-layer composite structure, which can avoid the following defects existing in a single-layer support: the presence of large through holes and low density defects, leakage when the casting liquid is applied to the support, resulting in pinholes and bright spots in the semipermeable membrane formed by the casting liquid.

[0042] The polyester support provided by the present disclosure has uniform pores, good air permeability, excellent tensile strength, strong adhesion to the semipermeable membrane, and excellent hydrophilicity and antibacterial properties. DETAILED DESCRIPTION

[0043] Various exemplary embodiments, features, and aspects of the present disclosure are described in detail below. The word "exemplary" is used herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior or preferred over other embodiments.

[0044] In addition, numerous specific details are provided in the following detailed description to better illustrate the present disclosure. Those skilled in the art will appreciate that the present disclosure can be practiced without certain specific details. In other instances, methods, means, equipment, and steps well known to those skilled in the art are not described in detail in order to highlight the main points of the present disclosure.

[0045] Unless otherwise stated, the units used in this specification are international standard units, and the numerical values ​​and numerical ranges appearing in this disclosure should be understood to include the inevitable systematic errors in industrial production.

[0046] In this specification, the use of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0047] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "embodiments," etc., mean that the specific elements (e.g., features, structures, properties, and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0048] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints A and B.

[0049] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 10-40°C.

[0050] The present disclosure provides a method for preparing a polyester support, which comprises the following steps:

[0051] Prepare a coated side fiber slurry and a non-coated side fiber slurry, wherein the fiber slurry contains main fibers and hot-melt bonding fibers, the diameter of the main fibers contained in the coated side fiber slurry is smaller than the diameter of the main fibers contained in the non-coated side fiber slurry, and the diameter of the hot-melt bonding fibers contained in the coated side fiber slurry is smaller than the diameter of the hot-melt bonding fibers contained in the non-coated side fiber slurry;

[0052] preparing a coated-side fiber layer and a non-coated-side fiber layer;

[0053] The coated surface fiber layer is subjected to hydrophilic antibacterial modification, wherein the hydrophilic antibacterial modification is performed by contacting the coated surface fiber layer with a modification solution, wherein the modification solution contains a hydrophilic monomer and an antibacterial functional material;

[0054] coating an adhesive coating composition on the non-coated fiber layer to form an intermediate adhesive layer, wherein the adhesive coating composition comprises an adhesive and ultrafine short fibers;

[0055] The hydrophilic antibacterial modified coated fiber layer is placed on the non-coated fiber layer with the intermediate adhesive layer, and hot pressed to form a polyester support;

[0056] The polyester support is post-treated.

[0057] The polyester support provided by the present disclosure has a specific three-layer composite structure, in which the coated surface fiber layer and the non-coated surface fiber layer are bonded by an intermediate adhesive layer, which can avoid the following defects existing in a single-layer support: the presence of large through holes and low density defects, leakage when the casting liquid is applied to the support, resulting in pinholes and bright spots in the semipermeable membrane formed by the casting liquid.

[0058] In the present disclosure, by using a main fiber with a relatively small diameter and a hot-melt adhesive fiber to form a coated surface fiber layer, better surface smoothness and pore uniformity can be ensured. By using a main fiber with a relatively large diameter and a hot-melt adhesive fiber to form a non-coated surface fiber layer, the bonding strength between the non-coated surface fiber layer and the intermediate adhesive layer can be ensured. By setting an intermediate adhesive layer, the tensile strength of the polyester support can be improved, and the larger pores in the polyester support can be filled, further improving the pore uniformity. While ensuring good air permeability of the support, the problem of leakage of the casting liquid caused by the low-density defects of the support is avoided, and the pinhole and bright spot problems caused by leakage are avoided. In addition, the three-layer composite structure can cover each other's defective positions, further improving the pore uniformity and improving the beneficial effects brought about by it.

[0059] In the present disclosure, by subjecting the coated surface fiber layer to hydrophilic antimicrobial modification, the hydrophobic fibers are transformed into hydrophilic fibers with bactericidal properties. This reduces water permeation resistance during the permeation process while further enhancing the interfacial bonding strength between the support and the polymer matrix used to form the semipermeable membrane (i.e., the polymer contained in the casting solution), and also improving the antimicrobial capacity of the support. The hydrophilic support can promote the transient phase transformation process of the casting solution, which is beneficial for the polymer matrix in the casting solution to form a macroporous structure, increase porosity, and reduce pore tortuosity.

[0060] The hydrophilic antimicrobial modification is performed by contacting the coated fiber layer with a modification solution containing a hydrophilic monomer and an antimicrobial functional material. The coated fiber layer undergoes pretreatment to generate active groups, which promote the introduction of the hydrophilic monomer via graft polymerization. Compared to hydrophilic modification via physical coating, the hydrophilic modification method employed in this disclosure offers greater stability over long-term operation and significantly improved performance.

[0061] In the present disclosure, the intermediate adhesive layer has a hollow microporous structure, and the adhesive coating composition used to form the intermediate adhesive layer contains an adhesive and ultrafine short fibers. By setting the intermediate adhesive layer, the bonding strength between the layers of the support body with a three-layer composite structure can be improved, thereby improving the overall tensile strength of the support body. The ultrafine short fibers can effectively control the distribution of micropore diameters in the intermediate adhesive layer.

[0062] Furthermore, the composition of the adhesive coating composition can be adjusted to suit specific application requirements, thereby adjusting the size, distribution, and viscosity of the micropore structure in the intermediate adhesive layer. This allows for the air permeability of the support while effectively ensuring that the casting solution, which will be applied to the coated fiber layer to form the semipermeable membrane, penetrates between one-third and one-half of the support's overall thickness.

[0063] At the same time, the middle adhesive layer can partially penetrate into the coating surface fiber layer, thereby forming a mortise and tenon structure inside the support body, further strengthening the anchoring effect between the coating surface fiber layer and the semipermeable membrane, and effectively avoiding semipermeable membrane defects caused by local lack of bonding between the support body and the semipermeable membrane.

[0064] In the preparation method disclosed herein, the main fiber is at least one of polyester fiber, polypropylene fiber, polyacrylate fiber, polyurethane fiber, polyamide fiber and polyimide fiber.

[0065] Preferably, the main fiber is polyester fiber, more preferably PET polyester fiber, and particularly preferably, the melting point of the PET polyester fiber is 250° C. and the fiber length is 2-8 mm.

[0066] The preparation method disclosed herein, wherein the hot-melt bonding fiber is at least one of a sheath-core type, a side-by-side type, a sea-island type and a pie-shaped bicomponent composite fiber.

[0067] Preferably, the hot-melt bonding fiber is at least one of COPET / PET sheath-core fiber, PE / PET sheath-core fiber and ES fiber (Ethylene-Propylene Side By Side) bicomponent sheath-core composite fiber, more preferably COPET / PET sheath-core fiber.

[0068] Preferably, when the surface layer / skin layer of the hot-melt adhesive fiber is modified COPET, the melting point of the modified COPET is 110-130° C., when the inner core is PET, the melting point of PET is 250° C., and the fiber length is 2-8 mm.

[0069] The preparation method disclosed herein, wherein in the coating surface fiber slurry, the diameter of the main fiber is 6.0-9.0 μm, more preferably 6.5-7.5 μm, the diameter of the hot-melt bonding fiber is 8.0-11.0 μm, more preferably 9.5-10.5 μm, and based on the total weight of the fibers contained in the coating surface fiber slurry, the content of the main fiber is 55-90 wt%, and the content of the hot-melt bonding fiber is 10-45 wt%.

[0070] In the non-coated surface fiber slurry, the diameter of the main fiber is 6.0-13.0 μm, more preferably 7.0-11.0 μm, and the diameter of the hot-melt bonding fiber is 8.0-14.0 μm, more preferably 9.5-11.5 μm. Based on the total weight of the fibers contained in the non-coated surface fiber slurry, the content of the main fiber is 60-95wt%, and the content of the hot-melt bonding fiber is 5-40wt%.

[0071] The coated-side fiber slurry and the uncoated-side fiber slurry may further include a dispersant. Preferably, the dispersant is at least one selected from a surfactant, an electrolyte inorganic salt, and a water-soluble polymer, more preferably a water-soluble polymer, and even more preferably PEO. The dispersant may be added in an amount of 1-5 wt %, more preferably 1-3 wt %, based on the weight of the fiber raw material. The addition of the dispersant can enhance lubrication between fibers, reduce the probability of fiber entanglement, and increase the viscosity of the fiber slurry to make flocculation between fibers more difficult, thereby improving the stability of the fiber suspension.

[0072] The preparation of fiber slurry can be carried out in the following manner: the raw fiber and dispersant are put into a fiber disperser filled with water, and the slurry is dispersed until the fibers are in a dispersed state; the obtained fiber slurry is pumped to a slurry storage tank, and the agitator is turned on, and the fiber slurry is stirred and dispersed until the fibers are in a single strand shape and suspended in water, thereby preparing coated surface fiber slurry and non-coated surface fiber slurry respectively.

[0073] The coated surface fiber layer and the non-coated surface fiber layer can be formed in the following manner: the fiber slurry is conveyed to a high-level stabilizing box by a chemical fiber pump to control the flow rate of the fiber slurry; the fiber slurry is dispersed to the net concentration through multiple punching and screening, and is flowed to the inclined mesh headbox; the fiber slurry is conveyed to the forming mesh through the inclined mesh headbox, and is dehydrated to form a wet fiber web; after pressing and roller pressing and dehydration, the fiber slurry is dried, and the temperature is controlled to be lower than the lower melting point of the sheath fiber and the core fiber of the hot-melt adhesive fiber, to respectively produce the coated surface fiber layer and the non-coated surface fiber layer.

[0074] Preferably, the drying treatment is one selected from hot air drying, infrared drying and Yankee drying, more preferably Yankee drying, and the temperature of the Yankee drying is preferably 80-110°C.

[0075] The preparation method disclosed herein, wherein the hydrophilic monomer is at least one of di(ethylene glycol) methyl ether methacrylate (DEGMEMA), hydroxyethyl methacrylate (HEMA), maleic anhydride, acrylamide, methacrylamide, acrylic acid and its esters, methacrylic acid and its esters, polyvinyl alcohol (PVA), and polyethylene glycol (PEG). Preferably, the concentration of the hydrophilic monomer is 1-10 wt % based on the weight of the modified solution.

[0076] The antibacterial functional material is at least one of an antibacterial functional monomer, a bactericidal nanomaterial and a natural biological molecule.

[0077] Preferably, the antibacterial functional monomer is at least one selected from polymer halamine, quaternary ammonium salt, quaternary phosphonium salt, polycation, guanidine and hydantoin, more preferably at least one selected from 3-hydroxymethyl-2,2,5,5-tetramethylimidazol-4-one, quaternized polyvinyl pyrrolidone, quaternized polymethacrylate N,N-dimethylaminoethyl ester, five-membered heterocyclic halogenated tetramethyl-4-imidazolidinone, polyhexamethylene biguanide hydrochloride and hydantoin.

[0078] Preferably, the concentration of the antibacterial functional monomer is 1-10 wt % based on the weight of the modified solution; when the antibacterial functional monomer is used as the antibacterial functional material, the modified material and the coated surface fiber layer are more likely to be combined in a covalent bond manner.

[0079] Preferably, the bactericidal nanomaterial is at least one selected from AgNPs (Ag nanoparticles), Pt nanoparticles, TiO2, CNTs (carbon nanotubes) and graphene, and the concentration of the bactericidal nanomaterial is preferably 1-5wt% based on the weight of the modified solution; when the bactericidal nanomaterial is used as the antibacterial functional material, the modified material is more combined by physical action with the help of the melting of hot-melt adhesive fibers.

[0080] Preferably, the natural biomolecule is chitosan, and its molecular weight is preferably 10,000 to 100,000. The concentration of the natural biomolecule is preferably 1 to 5 wt % based on the weight of the modified solution. When the natural biomolecule is used as the antimicrobial functional material, the modified material is bonded to the coated fiber layer by both covalent bonding and physical interaction.

[0081] Prior to the hydrophilic antimicrobial modification, the coated surface fiber layer is preferably pretreated to generate active groups. Preferably, the pretreatment is at least one of pre-irradiation and solution pretreatment. The pre-irradiation is preferably performed using a low-temperature plasma technique, such as corona discharge, glow discharge, dielectric barrier discharge, and arc discharge.

[0082] Although plasma etching or solution impregnation may cause a slight increase in the roughness of the fiber surface, in the subsequent hot melt rolling process, the melt flow coverage of the hot melt bonding fiber and the rolling action of the metal mirror roller can eliminate the effect of the increased fiber surface roughness, and ultimately will not have an adverse effect on the smoothness of the coated fiber layer.

[0083] The hydrophilic antibacterial modification of the coated surface fiber layer can be carried out in the following manner: preparing a modified solution using water or an organic solvent as a dispersion medium; subjecting the coated surface fiber layer to pre-irradiation technology and / or solution pretreatment to generate active groups, and then immersing the modified solution for surface grafting polymerization reaction; then, rinsing with ethanol and deionized water, respectively, and drying to constant weight.

[0084] Preferably, the surface graft polymerization reaction temperature of the hydrophilic monomer and the antibacterial functional monomer is 20-60° C., and the reaction time is 0.1-5 h.

[0085] The preparation method disclosed herein comprises applying an adhesive coating composition to the non-coated fiber layer to form an intermediate adhesive layer. The adhesive coating composition comprises an adhesive and ultrafine staple fibers. The adhesive is at least one of a silicone adhesive, an acrylic adhesive, an acrylate adhesive, and a polyurethane adhesive. Examples of the polyurethane adhesive include two-component polyurethane adhesives. Preferably, the adhesive is a silicone adhesive.

[0086] The concentration of the adhesive is preferably 35-45 wt % based on the weight of the adhesive coating composition.

[0087] The preparation method disclosed herein, wherein the ultrafine short fibers have a diameter of 2.0-5.0 μm and a length of 3.0-6.0 mm.

[0088] Preferably, the material of the ultrafine short fibers is at least one of PET and PP, and the concentration of the ultrafine short fibers is preferably 5-20 wt % based on the weight of the adhesive coating composition.

[0089] The adhesive coating composition further comprises a cross-linking agent, a catalyst, a coupling agent, an inhibitor, a tackifying resin, a foaming agent and the like.

[0090] The crosslinking agent is preferably hydroxy polysiloxane, and the concentration of the crosslinking agent is preferably 2-10 wt % based on the weight of the adhesive coating composition.

[0091] The catalyst is preferably a silver catalyst, and the concentration of the catalyst is preferably 2-5 wt % based on the weight of the adhesive coating composition.

[0092] The coupling agent is preferably at least one selected from titanate coupling agents, silane coupling agents and aluminates, more preferably aluminates. The concentration of the coupling agent is preferably 1-5 wt % based on the weight of the adhesive coating composition.

[0093] The inhibitor is preferably at least one of acetylenic alcohol and maleic alcohol. The concentration of the inhibitor is preferably 0.5-2 wt % based on the weight of the adhesive coating composition.

[0094] The tackifying resin is preferably MQ silicone resin, which is a compact spherical object with a double-layer structure. The concentration of the tackifying resin is preferably 10-50 wt % based on the weight of the adhesive coating composition.

[0095] The foaming agent is preferably at least one selected from alkane foaming agents, carbon dioxide, chlorinated hydrocarbon foaming agents, azo compound foaming agents, N-nitroso compound foaming agents and hydrazide compound foaming agents. The concentration of the foaming agent is preferably 10-30 wt % based on the weight of the adhesive coating composition.

[0096] The intermediate adhesive layer can be formed by coating the adhesive coating composition on the non-coated fiber layer, and preheating the composition to allow the foaming agent to act, with the preheating temperature maintained at 80-100° C. for 5-30 minutes.

[0097] The preparation method disclosed herein, wherein a hydrophilic antibacterial modified coated fiber layer is placed on a non-coated fiber layer having an intermediate adhesive layer, and hot pressing is performed to form a polyester support, can be performed in the following manner:

[0098] The hydrophilic antibacterial modified coated fiber layer is transferred to the non-coated fiber layer with the intermediate adhesive layer by a vacuum suction device, and then introduced into a two-roll hot press for hot rolling. The fiber layer is hot-melt rolled to generate strength to obtain a polyester support body.

[0099] The two-roll hot press comprises a lower roller, a metal mirror roller heated by heat-conducting oil, in contact with the coated fiber layer, and having a surface temperature higher than the melting point of the COPET fiber in the sheath layer of the heat-melting adhesive fiber in the coated fiber layer, and having a temperature of 120-160°C; an upper roller, a rubber roller, heated by conduction from the lower roller, in contact with the uncoated fiber layer, and having a surface temperature higher than the melting point of the COPET fiber in the sheath layer of the heat-melting adhesive fiber in the uncoated fiber layer, and having a temperature of 120-150°C; the temperature of the rollers is appropriately controlled to implement a non-drafting motion and adjust the length and smoothness of the polyester support;

[0100] The post-processing of the polyester support includes hot melt lamination again to control the thickness of the support, which can be carried out in the following ways:

[0101] The polyester support is introduced into a three-roll hot press for hot melt rolling again, and the temperature and linear pressure of the rollers are adjusted. The middle roller of the three-roll hot press is a metal mirror roller heated by thermal oil, and the roller surface temperature is 110-150°C. It is always in contact with the coated fiber layer. The upper and lower rollers are rubber rollers heated by conduction through the middle roller, and the roller surface temperature is 110-140°C. The rubber rollers are in contact with the non-coated fiber layer; preferably, the linear pressure between the middle roller and the upper roller is greater than the linear pressure between the middle roller and the lower roller.

[0102] Preferably, in this step, the operating linear speed of the three-roll hot press is 0.5-1% greater than the operating linear speed of the two-roll hot press in the previous hot melt rolling step.

[0103] The present disclosure provides a polyester support, which comprises a coated surface fiber layer, an intermediate adhesive layer and a non-coated surface fiber layer in sequence, wherein the coated surface fiber layer is hydrophilized and antibacterial modified, the intermediate adhesive layer comprises an adhesive and ultrafine short fibers, the coated surface fiber layer and the non-coated surface fiber layer each comprise a main fiber and a hot-melt bonding fiber, the diameter of the main fiber contained in the coated surface fiber layer is smaller than the diameter of the main fiber contained in the non-coated surface fiber layer, and the diameter of the hot-melt bonding fiber contained in the coated surface fiber layer is smaller than the diameter of the hot-melt bonding fiber contained in the non-coated surface fiber layer.

[0104] The description of each layer and the description of the hydrophilic antimicrobial modification are the same as those described above for the method of preparing the polyester support.

[0105] The polyester supports of the present disclosure can be advantageously applied in water treatment, filtration and separation.

[0106] Example

[0107] The embodiments of the present disclosure will be described in detail below with reference to the examples. However, those skilled in the art will appreciate that the following examples are intended only to illustrate the present disclosure and should not be construed as limiting the scope of the present disclosure. Where specific conditions are not specified in the examples, the experiments were performed under conventional conditions or the conditions recommended by the manufacturer. Where the manufacturer of the reagents or instruments is not specified, all are commercially available conventional products.

[0108] Comparative Example 1

[0109] Step (1): Dispersion pretreatment of raw fiber

[0110] PET main fibers (fiber diameter 7.13 μm, fiber length 6 mm, 60 wt%), COPET / PET sheath-core hot-melt bonding fibers (fiber diameter 10.08 μm, fiber length 6 mm, 38 wt%), and dispersant PEO (2 wt%) were placed into a fiber disperser filled with water, added to a specified liquid level, and slurried until the fibers were dispersed; the prepared fiber slurry was pumped to a slurry storage tank, and the slurry storage tank agitator was turned on to dilute and disperse the fiber slurry until the fibers were in a single strand and suspended in water, thereby preparing a coated surface fiber slurry;

[0111] PET main fibers (fiber diameter 9.56 μm, fiber length 6 mm, 65 wt%), COPET / PET sheath-core hot-melt bonding fibers (fiber diameter 10.5 μm, fiber length 6 mm, 33 wt%), and a dispersant PEO (2 wt%) were placed into a fiber disperser filled with water, added to a specified liquid level, and slurried until the fibers were dispersed; the obtained fiber slurry was pumped to a slurry storage tank, and the slurry storage tank agitator was turned on to dilute and disperse the fiber slurry until the fibers were in a single strand and suspended in water, thereby obtaining a non-coated fiber slurry;

[0112] Step (2): Papermaking to prepare the coated fiber layer and the non-coated fiber layer

[0113] The fiber slurry for the coating surface is conveyed to a high-level stabilizing box by a chemical fiber pump to control the flow rate of the fiber slurry; after multiple slurry flushing and screening, the fiber slurry is dispersed to the net concentration and conveyed to the inclined headbox; the fiber slurry is conveyed to the forming net through the inclined headbox, dehydrated and formed to obtain a wet fiber web; after pressing, roller pressing and dehydration, and Yankee drying at a temperature of 90°C, the coating surface fiber layer is obtained;

[0114] The non-coating layer fiber slurry is conveyed to a high-level slurry stabilization box by a chemical fiber pump to control the flow rate of the fiber slurry; after multiple slurrying and screening, the fiber slurry is dispersed to the net concentration and conveyed to the inclined wire headbox; the fiber slurry is conveyed to the forming wire through the inclined wire headbox, dehydrated and formed to obtain a wet fiber web; after pressing, roller pressing and dehydration, and Yankee drying at a temperature of 100°C, the non-coating surface fiber layer is obtained;

[0115] Step (3): Hot melt rolling

[0116] The coated fiber layer obtained in step (2) is transferred to the non-coated fiber layer by a vacuum suction device, and after preheating, it is introduced into a two-roll hot press for hot rolling treatment, and a non-drafting movement is implemented. The surface temperature of the lower roller is 130°C, and the surface temperature of the upper roller is 120°C. The fiber layer is hot-melt pressed to generate strength, thereby obtaining a support body;

[0117] Step (4): Control thickness by hot melt rolling

[0118] The support obtained in step (3) is introduced into a three-roll hot press for further hot rolling treatment, with the middle roll temperature being 125°C, the upper and lower roll temperatures being 110°C, and the operating line speed of the three-roll hot press being 0.5% higher than that of the two-roll hot press, and the thickness of the support is controlled by rolling to obtain a membrane support;

[0119] Step (5): Quality Inspection

[0120] The prepared membrane support was designated as W-1, and its appearance and physical properties were tested and the data were recorded.

[0121] Comparative Example 2

[0122] Comparative Example 2 was carried out in the same manner as Comparative Example 1, except that the fiber diameter and content of the main fiber and the hot-melt adhesive fiber in step (1) were changed as shown in Table 1 below, the surface temperature of the lower roller was 140°C, the surface temperature of the upper roller was 130°C in step (3), the temperature of the middle roller was 135°C, and the temperatures of the upper and lower rollers were 120°C in step (4), and the obtained membrane support was recorded as W-2.

[0123] Table 1

[0124] Comparative Example 3

[0125] Step (1): dispersion pretreatment of raw fiber, same as step (1) of comparative example 1;

[0126] Step (2): preparing a coated surface fiber layer and a non-coated surface fiber layer by papermaking, the same as step (2) of comparative example 1;

[0127] Step (3): Forming an intermediate adhesive layer

[0128] An adhesive coating composition is applied on the non-coated fiber layer, comprising 38 wt% of organic silicone adhesive, 5 wt% of PET fiber (fiber diameter 2 μm, fiber length 3 mm), 5 wt% of hydroxy polysiloxane, 3 wt% of silver catalyst, 2 wt% of aluminate, 1 wt% of alkynol, 28 wt% of MQ resin, and 18 wt% of p-toluenesulfonyl hydrazide. The preheating temperature is maintained at 85° C., and the reaction time is 10 min to allow the foaming agent to act, thereby forming an intermediate adhesive layer.

[0129] Step (4): hot melt rolling, same as step (3) of comparative example 1;

[0130] Step (5): Control the thickness by hot melt rolling, same as step (4) of comparative example 1;

[0131] Step (6): Quality inspection: the prepared membrane support is marked as W-3, and the appearance and physical properties are inspected and the data are recorded.

[0132] Comparative Example 4

[0133] Step (1): dispersion pretreatment of raw fiber, same as step (1) of comparative example 1;

[0134] Step (2): preparing a coated surface fiber layer and a non-coated surface fiber layer by papermaking, the same as step (2) of comparative example 1;

[0135] Step (3): Hydrophilic grafting modification of the coating surface fiber layer

[0136] Water was used as the dispersion medium, and 4 wt% HEMA monomer was added to prepare a monomer solution; after the coated surface fiber layer generated active groups through glow discharge technology, it was immersed in the monomer solution for surface graft polymerization reaction for 2 hours; it was washed with ethanol and deionized water respectively, and dried to constant weight.

[0137] Step (4): forming an intermediate adhesive layer, the same as step (3) of Comparative Example 3;

[0138] Step (5): hot melt rolling, same as step (3) of comparative example 1;

[0139] Step (6): Control the thickness by hot melt rolling, same as step (4) of comparative example 1;

[0140] Step (7): Quality inspection: the prepared membrane support is marked as W-4, and the appearance and physical properties are inspected and the data are recorded.

[0141] Comparative Example 5

[0142] Step (1): dispersion pretreatment of raw fiber, same as step (1) of comparative example 1;

[0143] Step (2): preparing a coated surface fiber layer and a non-coated surface fiber layer by papermaking, the same as step (2) of comparative example 1;

[0144] Step (3): Anti-pollution modification of the coated fiber layer

[0145] Water is used as a dispersion medium, and 5wt% of quaternized polyvinyl pyrrolidone is added to prepare a solution; after the coated surface fiber layer generates active groups through glow discharge technology, it is immersed in the solution for surface graft polymerization reaction for 2 hours; it is washed with ethanol and deionized water respectively, and dried to constant weight.

[0146] Step (4): forming an intermediate adhesive layer, the same as step (3) of Comparative Example 3;

[0147] Step (5): hot melt rolling, same as step (3) of comparative example 1;

[0148] Step (6): Control the thickness by hot melt rolling, same as step (4) of comparative example 1;

[0149] Step (7): Quality inspection: the prepared membrane support is marked as W-4, and the appearance and physical properties are inspected and the data are recorded.

[0150] Example 1

[0151] Step (1): Dispersion pretreatment of raw fiber

[0152] PET main fibers (fiber diameter 7.13 μm, fiber length 6 mm, 60 wt%), COPET / PET sheath-core hot-melt bonding fibers (fiber diameter 10.08 μm, fiber length 6 mm, 38 wt%), and dispersant PEO (2 wt%) were placed into a fiber disperser filled with water, added to a specified liquid level, and slurried until the fibers were dispersed; the prepared fiber slurry was pumped to a slurry storage tank, and the slurry storage tank agitator was turned on to dilute and disperse the fiber slurry until the fibers were in a single strand and suspended in water, thereby preparing a coated surface fiber slurry;

[0153] PET main fibers (fiber diameter 9.56 μm, fiber length 6 mm, 65 wt%), COPET / PET sheath-core hot-melt bonding fibers (fiber diameter 10.5 μm, fiber length 6 mm, 33 wt%), and a dispersant PEO (2 wt%) were placed into a fiber disperser filled with water, added to a specified liquid level, and slurried until the fibers were dispersed; the obtained fiber slurry was pumped to a slurry storage tank, and the slurry storage tank agitator was turned on to dilute and disperse the fiber slurry until the fibers were in a single strand and suspended in water, thereby obtaining a non-coated fiber slurry;

[0154] Step (2): Papermaking to prepare the coated fiber layer and the non-coated fiber layer

[0155] The fiber slurry for the coating surface is conveyed to a high-level stabilizing box by a chemical fiber pump to control the flow rate of the fiber slurry; after multiple slurry flushing and screening, the fiber slurry is dispersed to the net concentration and conveyed to the inclined headbox; the fiber slurry is conveyed to the forming net through the inclined headbox, dehydrated and formed to obtain a wet fiber web; after pressing, roller pressing and dehydration, and Yankee drying at a temperature of 90°C, the coating surface fiber layer is obtained;

[0156] The non-coated surface fiber slurry is conveyed to a high-level stabilizing box by a chemical fiber pump to control the flow rate of the fiber slurry; after multiple slurry flushing and screening, the fiber slurry is dispersed to the net concentration and conveyed to the inclined wire headbox; the fiber slurry is conveyed to the forming wire through the inclined wire headbox, dehydrated and formed to obtain a wet fiber web; after pressing, roller pressing and dehydration, and Yankee drying at a temperature of 100°C, the non-coated surface fiber layer is obtained;

[0157] Step (3): Hydrophilic antibacterial modification of the coating fiber layer

[0158] Using water as the dispersion medium, 4wt% HEMA monomer and 3wt% quaternized polyvinyl pyrrolidone were added to prepare a modification solution; after the coated fiber layer was subjected to glow discharge technology to generate active groups, it was immersed in the modification solution for surface grafting polymerization reaction for 3 hours; it was washed with ethanol and deionized water respectively, and dried to constant weight.

[0159] Step (4): Forming an intermediate adhesive layer

[0160] An adhesive coating composition is applied on the non-coated fiber layer, which comprises 38 wt% of organic silicone adhesive, 5 wt% of PET fiber (fiber diameter 2 μm, fiber length 3 mm), 5 wt% of hydroxy polysiloxane, 3 wt% of silver catalyst, 2 wt% of aluminate, 1 wt% of acetylene alcohol, 28 wt% of MQ resin, and 18 wt% of p-toluenesulfonyl hydrazide. The preheating temperature is maintained at 85° C. to allow the foaming agent to act and thereby form an intermediate adhesive layer.

[0161] Step (5): Hot melt rolling

[0162] The coated fiber layer obtained in step (2) is transferred to the non-coated fiber layer with the intermediate adhesive layer obtained in step (4) by a vacuum suction device, and after preheating, it is introduced into a two-roll hot press for hot rolling treatment, and a non-drafting movement is implemented. The surface temperature of the lower roller is 130°C, and the surface temperature of the upper roller is 120°C. After hot melting and rolling, strength is generated to obtain a support body;

[0163] Step (6): Control thickness by hot melt rolling

[0164] The support obtained in step (5) is introduced into a three-roll hot press for hot rolling treatment again, the middle roll temperature is 125°C, the upper and lower roll temperatures are 110°C, the three-roll hot rolling mill operating line speed is 0.5% higher than the two-roll hot press operating line speed, and the thickness of the support is controlled by rolling to obtain a membrane support;

[0165] Step (7): Quality Inspection

[0166] The prepared membrane support was designated as W-6, and its appearance and physical properties were tested, and the data were recorded.

[0167] Examples 2-4

[0168] Except for changing the fiber diameter and content of the main fiber and the hot-melt adhesive fiber in step (1), the composition and reaction time of the hydrophilic antibacterial modification solution, and the composition of the adhesive coating composition as shown in Table 2 below, Examples 2-4 were carried out in the same manner as Example 1, and the prepared membrane supports were designated as W-7, W-8, and W9, respectively.

[0169] Table 2

[0170] Performance Testing

[0171] 1) Test the grammage of the polyester support according to GBT 24218.1-2009.

[0172] 2) Polyester support thickness test: according to GBT 24218.2-2009 method.

[0173] 3) Smoothness test of polyester support: according to GBT 456-2002 method.

[0174] 4) Polyester support air permeability test: according to GB / T 24218.15-2018 method.

[0175] 5) Tensile strength test of polyester support: in accordance with GBT 24218.3-2010.

[0176] 6) Length-to-diameter ratio test of coated fiber: After the polyester support is fractured at low temperature, its cross section is observed. The fiber cross section is generally elliptical or irregularly elliptical. The ratio of the major diameter to the minor diameter of the coated fiber cross section is measured, and the ratio is the length-to-diameter ratio.

[0177] 7) Hydrophilicity test: The static contact angle of the coated fiber layer was tested. Contact angles between 0-60° were designated as hydrophilicity I, between 61-90° as slightly hydrophilicity I', between 91-120° as slightly hydrophobicity O', and between 121-180° as hydrophobicity O;

[0178] 8) Quantitative detection of antibacterial effect: Cut a 10mm×30mm sample and place it in a 150ml Erlenmeyer flask. Add 70ml of PBS buffer and 500μl of E. coli suspension respectively. Fix the flask on a shaking table and shake at 120r / min for 24 hours. Take 500μl of the shaken sample liquid, dilute it appropriately with PBS buffer, and then count the viable bacteria. At the same time, test the ordinary non-woven fabric support without antibacterial material, and record the viable bacteria count as W1 viable bacteria count. The sterilization rate is calculated as follows:

[0179] Sterilization rate (%) = (number of viable bacteria in W1 - number of viable bacteria in sample) / number of viable bacteria in W1 × 100%

[0180] 9) Curl Test: When a casting solution is applied to the coated fiber layer of a polyester support to form a semipermeable membrane, the membrane is observed to see if it curls toward the coated fiber layer. Curl is visually observed. If no curl is observed, mark "√"; if curl is observed, mark "×".

[0181] 10) Permeability Test: A casting solution containing 20 wt% polysulfone resin in DMF was applied to the coated surface of the polyester support. A polysulfone semipermeable membrane was formed on the coated surface via phase inversion. SEM images of the polysulfone semipermeable membrane cross-section were used to evaluate the degree of penetration of the membrane into the support.

[0182] √: The polysulfone resin only penetrates to the vicinity of the center of the support, and the use effect is good.

[0183] △: The polysulfone resin did not seep out from the non-coated fiber layer of the support, and the effect was average.

[0184] ×: The polysulfone resin seeped out of the non-coated fiber layer of the support, resulting in poor use effect.

[0185] 11) Adhesion test method:

[0186] One day after the preparation of the polyester support having the semipermeable membrane, the semipermeable membrane and the polyester support were slowly peeled off at the interface, and the "semipermeable membrane adhesion" was determined based on the resistance during the peeling.

[0187] √: The bonding strength between the semipermeable membrane and the support is very high and cannot be peeled off.

[0188] △: The bonding strength between the semipermeable membrane and the support is average, and the membrane is easily peeled off as a whole.

[0189] ×: Peeling occurred during the water washing or drying step after coating the semipermeable membrane.

[0190] 12) Surface smoothness after coating: Observe the smoothness on a micrograph. Obvious wrinkles are considered uneven, otherwise flat. If flat, mark "√"; if uneven, mark "×."

[0191] The above performance test results are shown in Table 3 below.

[0192] Table 3

[0193] The above performance test results demonstrate that the provision of an intermediate adhesive layer effectively improves the penetration of the casting solution into the polyester support while ensuring breathability. By selecting a fiber material of appropriate diameter, a polyester support with excellent smoothness and flatness can be prepared. Furthermore, the hydrophilic and antimicrobial modification not only does not adversely affect the basic properties of the support, but also effectively enhances its hydrophilicity, thereby strengthening the adhesion between the support and the semipermeable membrane. Furthermore, the antimicrobial modification significantly improves the support's anti-fouling capabilities. The polyester support obtained by the disclosed method exhibits superior overall performance.

[0194] It should be noted that, although the technical solutions of the present disclosure are described with specific examples, those skilled in the art will appreciate that the present disclosure should not be limited thereto.

[0195] While various embodiments of the present disclosure have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing a polyester support, characterized in that: The following steps are involved: Prepare a coated surface fiber slurry and a non-coated surface fiber slurry, wherein the fiber slurry contains main body fibers and hot-melt bonding fibers, the diameter of the main body fibers contained in the coated surface fiber slurry is smaller than the diameter of the main body fibers contained in the non-coated surface fiber slurry, and the diameter of the hot-melt bonding fibers contained in the coated surface fiber slurry is smaller than the diameter of the hot-melt bonding fibers contained in the non-coated surface fiber slurry; Prepare a coated surface fiber layer and a non-coated surface fiber layer; The coated surface fiber layer is subjected to hydrophilic antibacterial modification, wherein the hydrophilic antibacterial modification is performed by contacting the coated surface fiber layer with a modification solution, wherein the modification solution contains a hydrophilic monomer and an antibacterial functional material; Applying an adhesive coating composition on the non-coated surface fiber layer to form an intermediate adhesive layer, wherein the adhesive coating composition comprises an adhesive and ultrafine short fibers; Placing the coated surface fiber layer that has been hydrophilized and antibacterial modified on the non-coated surface fiber layer formed with the intermediate adhesive layer, and forming a polyester support body through heat pressing; The polyester support is post-treated.

2. The preparation method according to claim 1, wherein the main fiber is at least one of polyester fiber, polypropylene fiber, polyacrylate fiber, polyurethane fiber, polyamide fiber and polyimide fiber.

3. The preparation method according to claim 1 or 2, wherein the hot-melt adhesive fiber is at least one of a sheath-core type, a side-by-side type, a sea-island type and a pie-shaped bicomponent composite fiber.

4. The preparation method according to claim 1 or 2, wherein in the coated surface fiber slurry, the diameter of the main fiber is 6.0-9.0 μm, the diameter of the hot-melt bonding fiber is 8.0-11.0 μm, and based on the total weight of the fibers contained in the coated surface fiber slurry, the content of the main fiber is 55-90wt%, and the content of the hot-melt bonding fiber is 10-45wt%; in the non-coated surface fiber slurry, the diameter of the main fiber is 6.0-13.0 μm, the diameter of the hot-melt bonding fiber is 8.0-14.0 μm, and based on the total weight of the fibers contained in the non-coated surface fiber slurry, the content of the main fiber is 60-95wt%, and the content of the hot-melt bonding fiber is 5-40wt%.

5. according to the preparation method described in claim 1 or 2, wherein said hydrophilic monomer is at least one of di(ethylene glycol)methyl ether methacrylate DEGMEMA, hydroxyethyl methacrylate HEMA, maleic anhydride, acrylamide, methacrylamide, acrylic acid and esters thereof, methacrylic acid and esters thereof, polyvinyl alcohol PVA and polyethylene glycol PEG, and said antibacterial functional material is at least one of antibacterial functional monomer, bactericidal nano material and natural biomolecule.

6. The preparation method according to claim 1 or 2, wherein the adhesive is at least one of an organic silicone adhesive, an acrylic adhesive, an acrylate adhesive and a polyurethane adhesive.

7. The preparation method according to claim 1 or 2, wherein the ultrafine short fibers have a diameter of 2.0-5.0 μm and a length of 3.0-6.0 mm.

8. The preparation method according to claim 1 or 2, wherein before the hydrophilic antibacterial modification, the coating surface fiber layer is pretreated to generate active groups. 9 . The preparation method according to claim 8 , wherein the pretreatment is at least one of pre-irradiation and solution pretreatment.

10. A polyester support, which comprises a coated surface fiber layer, an intermediate adhesive layer and a non-coated surface fiber layer in sequence, characterized in that: The coated surface fiber layer is hydrophilized and antibacterial modified, the intermediate bonding layer contains an adhesive and ultrafine short fibers, the coated surface fiber layer and the non-coated surface fiber layer each contain a main fiber and a hot-melt bonding fiber, the diameter of the main fiber contained in the coated surface fiber layer is smaller than the diameter of the main fiber contained in the non-coated surface fiber layer, and the diameter of the hot-melt bonding fiber contained in the coated surface fiber layer is smaller than the diameter of the hot-melt bonding fiber contained in the non-coated surface fiber layer. 11 . The polyester support according to claim 10 , wherein the main fiber is at least one of polyester fiber, polypropylene fiber, polyacrylate fiber, polyurethane fiber, polyamide fiber and polyimide fiber.

12. The polyester support according to claim 10 or 11, wherein the hot-melt adhesive fiber is at least one of a sheath-core type, a side-by-side type, a sea-island type and a pie-shaped bicomponent composite fiber.

13. The polyester support according to claim 10 or 11, wherein in the coated surface fiber layer, the diameter of the main fiber is 6.0-9.0 μm, the diameter of the hot-melt bonding fiber is 8.0-11.0 μm, and based on the total weight of the fibers contained in the coated surface fiber layer, the content of the main fiber is 55-90wt%, and the content of the hot-melt bonding fiber is 10-45wt%; in the non-coated surface fiber layer, the diameter of the main fiber is 6.0-13.0 μm, the diameter of the hot-melt bonding fiber is 8.0-14.0 μm, and based on the total weight of the fibers contained in the non-coated surface fiber layer, the content of the main fiber is 60-95wt%, and the content of the hot-melt bonding fiber is 5-40wt%.

14. The polyester support according to claim 10 or 11, wherein the hydrophilic antibacterial modification is carried out by contacting the coated surface fiber layer with a modification solution, wherein the modification solution comprises a hydrophilic monomer and an antibacterial functional material, wherein the hydrophilic monomer is at least one of di(ethylene glycol) methyl ether methacrylate DEGMEMA, hydroxyethyl methacrylate HEMA, maleic anhydride, acrylamide, methacrylamide, acrylic acid and its esters, methacrylic acid and its esters, polyvinyl alcohol PVA and polyethylene glycol PEG, and the antibacterial functional material is at least one of an antibacterial functional monomer, a bactericidal nanomaterial and a natural biomolecule.

15. The polyester support according to claim 10 or 11, wherein the adhesive is at least one of an organic silicone adhesive, an acrylic adhesive, an acrylate adhesive and a polyurethane adhesive.

16. The polyester support according to claim 10 or 11, wherein the ultrafine short fibers have a diameter of 2.0-5.0 μm and a length of 3.0-6.0 mm.

17. Use of the polyester support according to any one of claims 10 to 16 in water treatment.

18. Use of the polyester support according to any one of claims 10 to 16 in filtration and / or separation.

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