Preparation method of polyester support body, polyester support body prepared by preparation method and application of polyester support body

Abstract

The invention relates to a preparation method of a polyester support body, the polyester support body prepared by the preparation method and application of the polyester support body. The preparation method comprises the following steps: preparing coated surface fiber slurry and non-coated surface fiber slurry; preparing a coating surface fiber layer and a non-coating surface fiber layer; carrying out hydrophilic antibacterial modification on the coated surface fiber layer; coating an adhesive coating composition on the non-coating surface fiber layer to form an intermediate adhesive layer; and placing the hydrophilic antibacterial modified coating surface fiber layer on the non-coating surface fiber layer on which the middle bonding layer is formed, and carrying out post-treatment to form the polyester support body. The polyester support disclosed by the invention has a three-layer composite structure, uniform pores, good air permeability, excellent tensile strength, strong bonding force with a semipermeable membrane, and excellent hydrophilicity and antibacterial property. The polyester support of the present invention can be advantageously used in water treatment, filtration and separation.

Description

Technical Field

[0001] The present invention relates to a preparation method of a polyester support, a polyester support prepared thereby and application thereof, belonging to the field of membranes for filtration and / or separation, and more specifically to a polyester support for compounding with a semipermeable membrane for water treatment. Background Art

[0002] In the fields of seawater desalination, domestic sewage treatment, drug concentration, hemodialysis, food concentration, etc., semipermeable membranes as a highly efficient filtration material have received more and more attention and application promotion. Semipermeable membranes are composed of synthetic resins such as cellulose resins, polyester resins, polysulfone resins, polyamide resins, and fluororesins. The membrane layer formed by these materials is thin and the body strength is low. It is difficult to operate stably for a long time under the rated working conditions of the semipermeable membrane and cannot be used alone. In order to ensure the strength required for operation, the composite use of the semipermeable membrane and the support body as a supporting material has become the most common implementation method of commercial semipermeable membranes.

[0003] The production methods of the support are mainly spunbond, needle-punch, spunlace, and melt-blown. Due to factors such as immature supporting equipment, high process technology barriers, and small market size, the global share of supports prepared by wet process is less than 3%. However, the support produced by wet process has a smooth surface, high porosity, low thermal shrinkage, and high strength, which can effectively guarantee the separation performance of semipermeable membranes, and thus becomes a commonly used porous support material in industrial membrane making. Polypropylene (PP) support and polyester (PET) support are two of the more commonly used support materials. Compared with polypropylene support, polyester support has higher thermal stability, longer anti-aging cycle, and better solvent resistance. Therefore, for separation membranes with higher separation accuracy and flux requirements, polyester support is more widely used.

[0004] The support body used as the substrate of the semipermeable membrane for water treatment must have excellent fiber web distribution uniformity, good microporous structure, high tensile strength, moderate polymer solution permeability, no fuzzing on the surface, no macropore defects, etc. However, the membrane support body and its key raw material, low-melting-point polyester fiber, are still monopolized by foreign companies such as Mitsubishi, Miki, Awa Paper, etc. The membrane support body is becoming a key link in the battle for the position in the membrane material industry chain.

[0005] Invention patent CN102574070B discloses a nonwoven 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 non-coated surface of the support.

[0006] 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 strict requirements on the tensile strength aspect ratio of the material.

[0007] Invention patent CN105040275B proposes a method for making a base non-woven fabric using three types of fibers as raw materials through wet molding technology. The slurry is always in a three-layer distribution state during the transportation and molding process due to the different specific gravity of the fibers, and is hot-pressed into a composite non-woven fabric with three layers: upper, middle, and lower. This three-layer distribution state is theoretically feasible, but in actual production, in order to avoid the fiber slurry being in a laminar state and causing slurry flocculation, the fiber slurry needs to be in a turbulent or micro-turbulent state during the transportation and molding process.

[0008] Invention patent CN103432912B discloses a composite support material for a semipermeable membrane and a method for manufacturing the same. By introducing a foam adhesive coating layer between the coating layer and the non-coating layer, the penetration of the semipermeable membrane solution to the non-coating surface of the composite support material is inhibited to a certain extent. The foam adhesive coating layer controls the tensile strength and barrier properties of the support layer by the coating amount, but the diameter of the micropore bubbles reaches 100μm. Too large a micropore diameter makes it difficult to effectively inhibit the semipermeable membrane solution from penetrating the non-woven fabric.

[0009] Looking at the structure of the support described in the prior art, it is difficult to solve the problems of curling of the coating surface and pinholes and defects that are prone to occur in the separation membrane layer while ensuring the inhibition of the penetration of the semipermeable membrane solution. In addition, due to the smooth surface of polyester fibers, the close arrangement of molecular structures, and the lack of polar functional groups in the molecular structure, the support prepared from them exhibits typical hydrophobicity and is difficult to establish a good interface interaction with the polymer matrix. However, the prior art rarely discloses methods for modifying the hydrophilicity and anti-pollution properties of polyester supports. Summary of the invention

[0010] Problem that the invention aims to solve

[0011] In order to solve the above technical problems, the purpose of the present invention is to provide a method for preparing a polyester support, a polyester support prepared thereby and applications thereof.

[0012] Solutions for solving problems

[0013] The inventors of the present invention have conducted in-depth research to achieve the above objectives and proposed a method for preparing a polyester support as described below, which comprises the following steps:

[0014] 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;

[0015] Prepare a coated surface fiber layer and a non-coated surface fiber layer;

[0016] 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;

[0017] 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;

[0018] 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;

[0019] The polyester support is post-treated.

[0020] In the preparation method of the present invention, the main fiber is at least one of polyester fiber, polypropylene fiber, polyacrylate fiber, polyurethane fiber, polyamide fiber and polyimide fiber.

[0021] In the preparation method of the present invention, the hot-melt bonding fiber is at least one of sheath-core type, side-by-side type, island-in-the-sea type and orange segment type bicomponent composite fibers.

[0022] The preparation method described in the present invention, 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%.

[0023] In the preparation method of the present invention, 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 antibacterial functional monomers, bactericidal nanomaterials and natural biological molecules.

[0024] In the preparation method of the present invention, the adhesive is at least one of an organic silicone adhesive, an acrylic adhesive, an acrylate adhesive and a polyurethane adhesive.

[0025] In the preparation method of the present invention, the ultrafine short fibers have a diameter of 2.0-5.0 μm and a length of 3.0-6.0 mm.

[0026] In the preparation method of the present invention, before the hydrophilic antibacterial modification, the coating surface fiber layer is pretreated to generate active groups.

[0027] In the preparation method of the present invention, the pretreatment is at least one of pre-irradiation and solution pretreatment.

[0028] The present invention also provides a polyester support body obtained by the preparation method described in the present invention, which comprises a coated surface fiber layer, an intermediate bonding layer and a non-coated surface fiber layer in sequence, characterized in that the coated surface fiber layer has been subjected to hydrophilic antibacterial modification, the intermediate bonding 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.

[0029] The polyester support of the present invention, wherein the main fiber is at least one of polyester fiber, polypropylene fiber, polyacrylate fiber, polyurethane fiber, polyamide fiber and polyimide fiber.

[0030] In the polyester support of the present invention, the hot-melt adhesive fiber is at least one of sheath-core type, side-by-side type, island-in-the-sea type and orange segment type bicomponent composite fibers.

[0031] The polyester support of the present invention comprises the following: 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 55-90 wt%, and the content of the hot-melt bonding fiber is 10-45 wt%; 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 60-95 wt%, and the content of the hot-melt bonding fiber is 5-40 wt%.

[0032] The polyester support described in the present invention, 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.

[0033] The polyester support of the present invention, wherein the adhesive is at least one of an organic silicone adhesive, an acrylic adhesive, an acrylate adhesive and a polyurethane adhesive.

[0034] The polyester support of the present invention has a diameter of 2.0-5.0 μm and a length of 3.0-6.0 mm.

[0035] The present invention also provides an application of the polyester support prepared by the preparation method of the present invention in water treatment.

[0036] The present invention also provides an application of a polyester support prepared according to the preparation method of the present invention in filtration and / or separation.

[0037] Effects of the Invention

[0038] The polyester support provided by the present invention 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 a casting liquid is applied to the support, resulting in pinholes and bright spots in the semipermeable membrane formed by the casting liquid.

[0039] The polyester support provided by the invention has uniform pores, good air permeability, excellent tensile strength, strong adhesion to the semipermeable membrane, and excellent hydrophilicity and antibacterial properties. DETAILED DESCRIPTION

[0040] Various exemplary embodiments, features and aspects of the present invention will be described in detail below. The word "exemplary" used here means "used as an example, embodiment or illustrative". Any embodiment described here as "exemplary" is not necessarily interpreted as being superior or better than other embodiments.

[0041] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In other examples, methods, means, equipment and steps well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0042] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0043] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0044] In this specification, the 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 exist in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0045] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0046] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 10-40°C.

[0047] The present invention provides a method for preparing a polyester support, which comprises the following steps:

[0048] 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;

[0049] Prepare a coated surface fiber layer and a non-coated surface fiber layer;

[0050] 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;

[0051] 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;

[0052] 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;

[0053] The polyester support is post-treated.

[0054] The polyester support provided by the present invention has a specific three-layer composite structure, wherein the coated surface fiber layer and the non-coated surface fiber layer are bonded by an intermediate bonding 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 a casting liquid is applied to the support, resulting in pinholes and bright spots in a semipermeable membrane formed by the casting liquid.

[0055] In the present invention, by using a main body 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 body 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, avoiding the leakage of the casting liquid caused by the low-density defects of the support, and avoiding pinholes and bright spots caused by leakage. 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.

[0056] In the present invention, by hydrophilizing and antibacterial modification of the coated surface fiber layer, the hydrophobic fiber is transformed into a hydrophilic fiber with bactericidal function, while reducing the water penetration resistance during the penetration process, the interface bonding strength between the support and the polymer matrix (i.e., the polymer contained in the casting liquid) used to form the semipermeable membrane is further improved, and the antibacterial ability of the support is improved. The hydrophilic support can promote the instantaneous phase transformation process of the casting liquid, which is beneficial for the polymer matrix in the casting liquid to form a macroporous structure, increase the porosity, and reduce the tortuosity of the pores.

[0057] 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, and the coated surface fiber layer is pretreated to generate active groups, which promote the introduction of the hydrophilic monomer through a graft polymerization reaction. Compared with the hydrophilic modification performed by physical coating, the modification effect brought about by the hydrophilic modification method adopted in the present invention has better stability in long-term operation and more obvious performance improvement.

[0058] In the present invention, the intermediate adhesive layer has a hollow microporous structure, and the adhesive coating composition used to form the intermediate adhesive layer comprises an adhesive and ultrafine short fibers. By setting the intermediate adhesive layer, the bonding strength between the layers of the support body having 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.

[0059] In addition, the composition of the adhesive coating composition can be adjusted according to specific practical application requirements to adjust the size, distribution and arrangement of the micropore structure and the viscosity of the intermediate adhesive layer. While ensuring the air permeability of the support, the casting liquid to be applied to the coated fiber layer to form a semipermeable membrane can be effectively ensured to penetrate into 1 / 3 to 1 / 2 of the overall thickness of the support by adjusting the size and arrangement of the micropores.

[0060] 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.

[0061] In the preparation method of the present invention, the main fiber is at least one of polyester fiber, polypropylene fiber, polyacrylate fiber, polyurethane fiber, polyamide fiber and polyimide fiber.

[0062] 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.

[0063] In the preparation method of the present invention, the hot-melt bonding fiber is at least one of sheath-core type, side-by-side type, island-in-the-sea type and orange segment type bicomponent composite fibers.

[0064] Preferably, the hot-melt adhesive fiber is at least one of COPET / PET core-sheath fiber, PE / PET core-sheath fiber and ES fiber (Ethylene-Propylene Side By Side) bicomponent core-sheath type composite fiber, more preferably COPET / PET core-sheath fiber.

[0065] 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.

[0066] The preparation method described in the present invention, wherein in the coating surface fiber slurry, the diameter of the main fiber is 6.0-9.0μm, more preferably 6.5-7.5μm, the diameter of the hot-melt bonding fiber is 8.0-11.0μm, more preferably 9.5-10.5μm, and based on the total weight of the fibers contained in the coating surface fiber slurry, the content of the main fiber is 55-90wt%, and the content of the hot-melt bonding fiber is 10-45wt%.

[0067] 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, the diameter of the hot-melt bonding fiber is 8.0-14.0 μm, more preferably 9.5-11.5 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%.

[0068] The coated surface fiber slurry and the non-coated surface 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, and the amount of the dispersant added may be 1-5wt% of the weight of the fiber raw material, more preferably 1-3wt%. Adding a dispersant can increase the lubrication between fibers, reduce the probability of fiber entanglement, and increase the viscosity of the fiber slurry to make flocculation between fibers difficult, thereby improving the stability of the fiber suspension.

[0069] The preparation of fiber slurry can be carried out in the following manner: 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 and suspended in water, thereby respectively preparing coated surface fiber slurry and non-coated surface fiber slurry.

[0070] 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-position stabilizing box by a chemical fiber pump to control the flow rate of the fiber slurry; the fiber slurry is dispersed to a net concentration through multiple slurrying and screening, and is conveyed to an inclined net headbox; the fiber slurry is conveyed to a forming net through the inclined net headbox, and is dehydrated and formed to obtain a wet fiber net; after dehydration through pressing and roller pressing, 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 obtain the coated surface fiber layer and the non-coated surface fiber layer.

[0071] 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.

[0072] The preparation method of the present invention, 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, based on the weight of the modified solution, the concentration of the hydrophilic monomer is 1-10wt%.

[0073] The antibacterial functional material is at least one of an antibacterial functional monomer, a bactericidal nanomaterial and a natural biological molecule.

[0074] 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.

[0075] Preferably, based on the weight of the modified solution, the concentration of the antibacterial functional monomer is 1-10wt%; when the antibacterial functional monomer is used as the antibacterial functional material, the modified material is combined with the coated surface fiber layer more in the form of covalent bonds.

[0076] 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.

[0077] Preferably, the natural biomolecule is chitosan, and its molecular weight is preferably 10000-100000, and the concentration of the natural biomolecule is preferably 1-5wt% based on the weight of the modified solution. When the natural biomolecule is used as the antibacterial functional material, the modified material is combined with the coating surface fiber layer by covalent bonds and physical action at the same time.

[0078] Before the hydrophilic antibacterial 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 a low-temperature plasma technology, such as corona discharge, glow discharge, dielectric barrier discharge and arc discharge.

[0079] 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, so that it will not have an adverse effect on the smoothness of the coated fiber layer in the end.

[0080] 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 coated surface fiber layer in the modified solution for surface grafting polymerization reaction; then, rinsing with ethanol and deionized water, respectively, and drying to constant weight.

[0081] 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.

[0082] The preparation method of the present invention comprises coating 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. The adhesive is at least one of an organic silicone adhesive, an acrylic adhesive, an acrylate adhesive, and a polyurethane adhesive. Examples of the polyurethane adhesive include a two-component polyurethane adhesive, etc. Preferably, the adhesive is an organic silicone adhesive.

[0083] The concentration of the adhesive is preferably 35-45 wt % based on the weight of the adhesive coating composition.

[0084] In the preparation method of the present invention, the ultrafine short fibers have a diameter of 2.0-5.0 μm and a length of 3.0-6.0 mm.

[0085] Preferably, the material of the ultrafine short fibers is at least one of PET and PP, and based on the weight of the adhesive coating composition, the concentration of the ultrafine short fibers is preferably 5-20wt%.

[0086] The adhesive coating composition also includes a crosslinking agent, a catalyst, a coupling agent, an inhibitor, a tackifying resin, a foaming agent, and the like.

[0087] The crosslinking agent is preferably hydroxypolysiloxane, and the concentration of the crosslinking agent is preferably 2-10 wt % based on the weight of the adhesive coating composition.

[0088] 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.

[0089] The coupling agent is preferably at least one selected from titanate coupling agents, silane coupling agents and aluminates, more preferably aluminates, and the concentration of the coupling agent is preferably 1-5 wt % based on the weight of the adhesive coating composition.

[0090] 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.

[0091] The tackifying resin is preferably MQ silicone resin, which is a compact spherical substance 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.

[0092] 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, and the concentration of the foaming agent is preferably 10-30wt% based on the weight of the adhesive coating composition.

[0093] The intermediate adhesive layer can be formed by coating the adhesive coating composition on the non-coated fiber layer, and preheating the layer to allow the foaming agent to act, wherein the preheating temperature is maintained at 80-100° C. for 5-30 minutes.

[0094] The preparation method of the present invention, wherein the coated surface fiber layer that has been hydrophilized and antibacterial modified is placed on the non-coated surface fiber layer formed with the intermediate adhesive layer, and hot-pressed to form a polyester support, can be carried out in the following manner:

[0095] 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 after drying, it is introduced into a two-roll hot press for hot rolling. The fiber layer is subjected to hot melt rolling to generate strength to obtain a polyester support body.

[0096] The two-roll hot press machine has a lower roller which is a metal mirror roller heated by heat-conducting oil, in contact with the coated fiber layer, and a surface temperature which is higher than the melting point of the COPET fiber of the heat-melting adhesive fiber of the coated fiber layer, and a temperature of 120-160°C; an upper roller which is a rubber roller, heated by conduction from the lower roller, in contact with the non-coated fiber layer, and a surface temperature which is higher than the melting point of the COPET fiber of the heat-melting adhesive fiber of the non-coated fiber layer, and a temperature of 120-150°C; the temperature of the roller is appropriately controlled, and a non-drafting movement is implemented to adjust the progress and smoothness of the polyester support;

[0097] The post-treatment of the polyester support includes hot melt rolling again to control the thickness of the support, which can be carried out in the following manner:

[0098] The polyester support is introduced into a three-roll hot press for hot melt rolling again, and the temperature and line 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, which 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, and the rubber roller is in contact with the non-coated fiber layer; preferably, the line pressure between the middle roller and the upper roller is greater than the line pressure between the middle roller and the lower roller.

[0099] Preferably, in this step, the operating line speed of the three-roll hot press is 0.5-1% greater than the operating line speed of the two-roll hot press in the previous hot melt rolling step.

[0100] The polyester support provided by the present invention comprises a coating surface fiber layer, an intermediate bonding layer and a non-coating surface fiber layer in sequence, wherein the coating surface fiber layer is subjected to hydrophilic antibacterial modification, the intermediate bonding layer comprises an adhesive and ultrafine short fibers, the coating surface fiber layer and the non-coating surface fiber layer respectively comprise main fibers and hot-melt bonding fibers, the diameter of the main fibers contained in the coating surface fiber layer is smaller than the diameter of the main fibers contained in the non-coating surface fiber layer, and the diameter of the hot-melt bonding fibers contained in the coating surface fiber layer is smaller than the diameter of the hot-melt bonding fibers contained in the non-coating surface fiber layer.

[0101] The description of each layer and the description of the hydrophilic antibacterial modification are the same as those in the above description of the method for preparing the polyester support.

[0102] The polyester support of the present invention can be advantageously used in water treatment, filtration and separation.

[0103] Example

[0104] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0105] Comparative Example 1

[0106] Step (1): Dispersion pretreatment of raw fiber

[0107] Put PET main fiber (fiber diameter 7.13 μm, fiber length 6 mm, 60 wt%), COPET / PET core-skin hot-melt bonding fiber (fiber diameter 10.08 μm, fiber length 6 mm, 38 wt%) and dispersant PEO (2 wt%) into a fiber disperser filled with water, add to a specified liquid level, and slurry until the fibers are dispersed; pump the obtained fiber slurry to a slurry storage tank, turn on the slurry storage tank agitator, dilute and disperse the fiber slurry until the fibers are in a single strand and suspended in water, and obtain a coated surface fiber slurry;

[0108] Put PET main fiber (fiber diameter 9.56 μm, fiber length 6 mm, 65 wt%), COPET / PET core-skin hot-melt bonding fiber (fiber diameter 10.5 μm, fiber length 6 mm, 33 wt%) and dispersant PEO (2 wt%) into a fiber disperser filled with water, add to a specified liquid level, and slurry until the fibers are in a dispersed state; pump the obtained fiber slurry to a slurry storage tank, turn on the slurry storage tank agitator, dilute and disperse the fiber slurry until the fibers are in a single fiber shape and suspended in water, and obtain a non-coated surface fiber slurry;

[0109] Step (2): Papermaking to prepare the coated surface fiber layer and the non-coated surface fiber layer

[0110] The fiber slurry on the coating surface is conveyed to a high-position stabilizing box by a chemical fiber pump to control the flow of the fiber slurry; after multiple slurrying and screening, the fiber slurry is dispersed to the net concentration and conveyed to the inclined net headbox; the fiber slurry is conveyed to the forming net through the inclined net headbox, and is dehydrated and formed to obtain a wet fiber net; after pressing, roller pressing and dehydration, and Yankee cylinder drying at a temperature of 90°C, a coating surface fiber layer is obtained;

[0111] The fiber slurry of the non-coating layer is conveyed to a high-position stabilizing box by a chemical fiber pump to control the flow of the fiber slurry; after multiple slurrying and screening, the fiber slurry is dispersed to the net concentration and conveyed to the inclined net headbox; the fiber slurry is conveyed to the forming net through the inclined net headbox, and is dehydrated and formed to obtain a wet fiber net; after pressing, roller pressing and dehydration, and Yankee drying at a temperature of 100°C, a non-coating surface fiber layer is obtained;

[0112] Step (3): Hot melt rolling

[0113] 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 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, and a support body is obtained;

[0114] Step (4): Control thickness by hot melt rolling

[0115] The support obtained in step (3) is introduced into a three-roll hot press for hot rolling again, the middle roll temperature is 125°C, the upper and lower roll temperatures are 110°C, the three-roll hot press line speed is 0.5% higher than the two-roll hot press line speed, and the thickness of the support is controlled by rolling to obtain a membrane support;

[0116] Step (5): Quality Inspection

[0117] The prepared membrane support was designated as W-1, and its appearance and physical properties were tested and the data were recorded.

[0118] Comparative Example 2

[0119] Example 2 was carried out in the same manner as Example 1, except that the fiber diameter and content of the main fiber and the hot-melt bonding fiber in step (1) were changed as shown in Table 1, 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.

[0120] Table 1

[0121]

[0122] Comparative Example 3

[0123] Step (1): dispersion pretreatment of raw material fibers, same as step (1) of comparative example 1;

[0124] Step (2): preparing a coated surface fiber layer and a non-coated surface fiber layer by papermaking, which is the same as step (2) of comparative example 1;

[0125] Step (3): Forming an intermediate bonding layer

[0126] An adhesive coating composition is coated on the non-coated fiber layer, which includes 38wt% organic silicone adhesive, 5wt% PET fiber (fiber diameter 2μm, fiber length 3mm), 5wt% hydroxy polysiloxane, 3wt% silver catalyst, 2wt% aluminate, 1wt% acetylenic alcohol, 28wt% MQ resin, and 18wt% p-toluenesulfonyl hydrazide. The preheating temperature is maintained at 85°C and the reaction time is 10min to allow the foaming agent to act to form an intermediate adhesive layer.

[0127] Step (4): hot melt rolling, same as step (3) of comparative example 1;

[0128] Step (5): Control the thickness by hot melt rolling, which is the same as step (4) of comparative example 1;

[0129] Step (6): Quality inspection: the prepared membrane support is denoted as W-3, and the appearance and physical properties are inspected and the data are recorded.

[0130] Comparative Example 4

[0131] Step (1): dispersion pretreatment of raw material fibers, same as step (1) of comparative example 1;

[0132] Step (2): preparing a coated surface fiber layer and a non-coated surface fiber layer by papermaking, which is the same as step (2) of comparative example 1;

[0133] Step (3): Hydrophilic grafting modification of the coated fiber layer

[0134] Using water as the dispersion medium, 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 grafting polymerization reaction for 2 hours; it was washed with ethanol and deionized water respectively, and dried to constant weight.

[0135] Step (4): forming an intermediate adhesive layer, which is the same as step (3) of Comparative Example 3;

[0136] Step (5): hot melt rolling, same as step (3) of comparative example 1;

[0137] Step (6): Control the thickness by hot melt rolling, which is the same as step (4) of comparative example 1;

[0138] Step (7): Quality inspection: the prepared membrane support is denoted as W-4, and the appearance and physical properties are inspected and the data are recorded.

[0139] Comparative Example 5

[0140] Step (1): dispersion pretreatment of raw material fibers, same as step (1) of comparative example 1;

[0141] Step (2): preparing a coated surface fiber layer and a non-coated surface fiber layer by papermaking, which is the same as step (2) of comparative example 1;

[0142] Step (3): Anti-pollution modification of the coated fiber layer

[0143] Water is used as a dispersion medium, and 5 wt% of quaternary ammonium 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.

[0144] Step (4): forming an intermediate adhesive layer, which is the same as step (3) of Comparative Example 3;

[0145] Step (5): hot melt rolling, same as step (3) of comparative example 1;

[0146] Step (6): Control the thickness by hot melt rolling, which is the same as step (4) of comparative example 1;

[0147] Step (7): Quality inspection: the prepared membrane support is denoted as W-4, and the appearance and physical properties are inspected and the data are recorded.

[0148] Example 1

[0149] Step (1): Dispersion pretreatment of raw fiber

[0150] Put PET main fiber (fiber diameter 7.13 μm, fiber length 6 mm, 60 wt%), COPET / PET core-skin hot-melt bonding fiber (fiber diameter 10.08 μm, fiber length 6 mm, 38 wt%) and dispersant PEO (2 wt%) into a fiber disperser filled with water, add to a specified liquid level, and slurry until the fibers are dispersed; pump the obtained fiber slurry to a slurry storage tank, turn on the slurry storage tank agitator, dilute and disperse the fiber slurry until the fibers are in a single strand and suspended in water, and obtain a coated surface fiber slurry;

[0151] Put PET main fiber (fiber diameter 9.56 μm, fiber length 6 mm, 65 wt%), COPET / PET core-skin hot-melt bonding fiber (fiber diameter 10.5 μm, fiber length 6 mm, 33 wt%) and dispersant PEO (2 wt%) into a fiber disperser filled with water, add to a specified liquid level, and slurry until the fibers are in a dispersed state; pump the obtained fiber slurry to a slurry storage tank, turn on the slurry storage tank agitator, dilute and disperse the fiber slurry until the fibers are in a single fiber shape and suspended in water, and obtain a non-coated surface fiber slurry;

[0152] Step (2): Papermaking to prepare the coated surface fiber layer and the non-coated surface fiber layer

[0153] The fiber slurry on the coating surface is conveyed to a high-position stabilizing box by a chemical fiber pump to control the flow of the fiber slurry; after multiple slurrying and screening, the fiber slurry is dispersed to the net concentration and conveyed to the inclined net headbox; the fiber slurry is conveyed to the forming net through the inclined net headbox, and is dehydrated and formed to obtain a wet fiber net; after pressing, roller pressing and dehydration, and Yankee cylinder drying at a temperature of 90°C, a coating surface fiber layer is obtained;

[0154] The non-coated surface fiber slurry is conveyed to a high-position stabilizing box by a chemical fiber pump to control the flow of the fiber slurry; after multiple slurrying and screening, the fiber slurry is dispersed to the net concentration and conveyed to the inclined net headbox; the fiber slurry is conveyed to the forming net through the inclined net headbox, and is dehydrated and formed to obtain a wet fiber net; after pressing, roller pressing and dehydration, and Yankee drying at a temperature of 100°C, a non-coated surface fiber layer is obtained;

[0155] Step (3): Hydrophilic antibacterial modification of the coated fiber layer

[0156] Using water as the dispersion medium, 4wt% HEMA monomer and 3wt% quaternized polyvinyl pyrrolidone were added to prepare a modified solution; after the coated surface fiber layer was subjected to glow discharge technology to generate active groups, it was immersed in the modified solution for surface grafting polymerization reaction for 3 hours; it was washed with ethanol and deionized water respectively, and dried to constant weight.

[0157] Step (4): Forming an intermediate bonding layer

[0158] An adhesive coating composition is coated on the non-coated fiber layer, which includes 38wt% organic silicone adhesive, 5wt% PET fiber (fiber diameter 2μm, fiber length 3mm), 5wt% hydroxy polysiloxane, 3wt% silver catalyst, 2wt% aluminate, 1wt% acetylenic alcohol, 28wt% MQ resin, and 18wt% p-toluenesulfonyl hydrazide. The preheating temperature is maintained at 85°C to allow the foaming agent to act and thus form an intermediate adhesive layer.

[0159] Step (5): Hot melt rolling

[0160] The coated surface fiber layer obtained in step (2) is transferred to the non-coated surface 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 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;

[0161] Step (6): Control thickness by hot melt rolling

[0162] The support obtained in step (5) is introduced into a three-roll hot press for hot rolling again, the middle roll temperature is 125°C, the upper and lower roll temperatures are 110°C, the three-roll hot press line speed is 0.5% higher than the two-roll hot press line speed, and the thickness of the support is controlled by rolling to obtain a membrane support;

[0163] Step (7): Quality Inspection

[0164] The prepared membrane support was marked as W-6, and its appearance and physical properties were tested and the data were recorded.

[0165] Embodiment 2-4

[0166] 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 respectively recorded as W-7, W-8 and W9.

[0167] Table 2

[0168]

[0169] Performance Testing

[0170] 1) Test the grammage of the polyester support according to GBT 24218.1-2009 method.

[0171] 2) Thickness test of polyester support: according to GBT 24218.2-2009 method.

[0172] 3) Smoothness test of polyester support: according to GBT 456-2002 method.

[0173] 4) Air permeability test of polyester support: according to GB / T 24218.15-2018 method.

[0174] 5) Tensile strength test of polyester support: in accordance with GBT 24218.3-2010.

[0175] 6) Test of aspect ratio of coated surface fiber: After the polyester support is fractured at low temperature, its cross section is observed. The fiber cross section is generally elliptical or irregularly close to an ellipse. The major diameter and minor diameter of the coated surface fiber cross section are measured, and their ratio is the aspect ratio.

[0176] 7) Hydrophilicity test: Test the static contact angle of the coated fiber layer. The contact angle between 0-60° is recorded as hydrophilicity I, between 61-90° is recorded as slightly hydrophilicity I', between 91-120° is recorded as slightly hydrophobicity O', and between 121-180° is recorded as hydrophobicity O;

[0177] 8) Quantitative detection of antibacterial effect: Cut a sample of 10mm×30mm, put the sample into a 150ml Erlenmeyer flask, add 70ml PBS buffer and 500μl E. coli suspension respectively, fix the Erlenmeyer 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 live bacteria culture. At the same time, test the ordinary non-woven fabric support without antibacterial material, and record the number of live bacteria as W1 live bacteria. The sterilization rate is calculated as follows:

[0178] Sterilization rate (%) = (number of live bacteria in W1 - number of live bacteria in sample) / number of live bacteria in W1 × 100%

[0179] 9) Curl test: When the casting solution is applied to the coated fiber layer of the polyester support to form a semipermeable membrane, observe whether it curls toward the coated fiber layer. Curl is observed by naked eyes. If no curl is found, it is marked as "√", and if curl occurs, it is marked as "×".

[0180] 10) Permeability test: A casting solution was applied on the fiber layer on the coated surface of the polyester support, wherein the casting solution was a DMF solution containing 20 wt% polysulfone resin, and a polysulfone semipermeable membrane was formed on the coated surface through phase inversion. The penetration degree of the semipermeable membrane on the support was evaluated by SEM images of the cross section of the polysulfone semipermeable membrane.

[0181] √: The polysulfone resin only penetrates into the vicinity of the center of the support, and the use effect is good.

[0182] △: The polysulfone resin did not seep out from the non-coated fiber layer of the support, and the use effect was average.

[0183] ×: The polysulfone resin seeps out of the non-coated fiber layer of the support body, and the use effect is poor.

[0184] 11) Adhesion test method:

[0185] 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.

[0186] √: The bonding strength between the semipermeable membrane and the support is very high and cannot be peeled off.

[0187] △: The bonding strength between the semipermeable membrane and the support is average and the membrane is easily peeled off as a whole.

[0188] ×: Peeling occurred during the washing or drying step after coating of the semipermeable membrane.

[0189] 12) Method for judging the surface flatness after coating: observe the flatness on the micrograph. If there are obvious wrinkles, it is considered uneven, otherwise it is flat. If it is flat, it is marked as "√", if it is uneven, it is marked as "×".

[0190] The above performance test results are shown in Table 3 below.

[0191] Table 3

[0192]

[0193] From the above performance test results, it can be seen that by setting the intermediate adhesive layer, the penetration of the casting liquid into the polyester support is effectively improved while ensuring air permeability, and by selecting a fiber material with a suitable diameter, a polyester support with good smoothness and flatness can be prepared. In addition, the hydrophilic antibacterial modification not only does not have an adverse effect on the basic performance of the support, but also effectively improves the hydrophilicity of the support, thereby enhancing the adhesion between the support and the semipermeable membrane, and the antibacterial modification greatly improves the anti-pollution ability of the support. The comprehensive performance of the polyester support obtained by the method of the present invention is more excellent.

[0194] It should be noted that, although the technical solution of the present invention is introduced with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0195] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill 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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