Melt-blown PBT non-woven fabric composite filter material and preparation method and application thereof

Abstract

The application relates to the field of filter materials, in particular to a melt-blown PBT non-woven fabric composite filter material and a preparation method and application thereof. The melt-blown PBT non-woven fabric composite filter material comprises a care net layer, a filter paper layer and a bottom layer PBT melt-blown fabric, and the raw material of the bottom layer PBT melt-blown fabric comprises heparinized TPU and PBT in a weight ratio of 1: (3-5). The preparation method of the heparinized TPU is as follows: 1) TPU is dissolved to obtain a TPU solution, and the temperature is lowered to 38-42 DEG C; 2) heparin sulfate is dissolved to obtain a heparin sulfate solution; 3) the heparin sulfate solution is added dropwise into the TPU solution while stirring, and shear homogenization is carried out; and 4) drying is carried out to obtain heparinized TPU. The filter material is prepared by compounding TPU modified by heparin sulfate and PBT, the thrombosis risk in the blood filtration process is significantly reduced, and the platelet reduction rate in the blood filtration is as low as 25.4-14.9%.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of filter materials, in particular to a melt-blown PBT non-woven fabric composite filter material and a preparation method and application thereof. BACKGROUND

[0002] As an important part of the human body to resist bacteria and virus attacks from the outside world, white blood cells will attack cells different from the recipient's own cells during blood transfusion, causing a series of transfusion side effects such as non-hemolytic fever reaction, adult respiratory distress syndrome and post-transfusion graft-versus-host disease. Therefore, removing white blood cells is an essential step before clinical blood transfusion.

[0003] Currently, the main methods for removing white blood cells include centrifugation, washing, freezing glycerol method, ultraviolet or radiation irradiation method and filtration. Among them, filtration is the most effective and economical method for white blood cell removal. White blood cell removal filter materials are usually composed of non-woven fabrics made of PBT, PET, PP, PE and other materials. Such filter materials have good biocompatibility and chemical stability.

[0004] Applicants found that the hydrophobicity of the surface of the existing filter material leads to irreversible adsorption of fibrinogen, forming a "protein crown" - exposing the gamma chain binding site - platelet adhesion and activation, and self-activation of coagulation factor XII after contacting the negatively charged surface, initiating explosive generation of thrombin, which is prone to thrombosis. SUMMARY

[0005] In order to reduce the formation of thrombus during blood filtration, the present application provides a melt-blown PBT non-woven fabric composite filter material and a preparation method and application thereof.

[0006] In a first aspect, the present application provides a melt-blown PBT non-woven fabric composite filter material, which adopts the following technical solution.

[0007] A melt-blown PBT non-woven fabric composite filter material, comprising a care net layer, a filter paper layer and a bottom layer PBT melt-blown fabric, characterized in that the raw material of the bottom layer PBT melt-blown fabric comprises heparinized TPU and PBT in a weight ratio of 1: (3-5), and the preparation method of the heparinized TPU is as follows:

[0008] 1) Dissolve TPU to obtain a TPU solution, and cool it to 38-42℃;

[0009] 2) Dissolve heparan sulfate to obtain a heparan sulfate solution;

[0010] 3) Add the heparan sulfate solution to the TPU solution drop by drop while stirring to perform shear homogenization;

[0011] 4) Dry to obtain heparinized TPU.

[0012] By adopting the above technical scheme, the heparan sulfate modified TPU / PBT composite material significantly reduces the thrombosis risk through three mechanisms: 1) Heparan sulfate biological activity: the specific sulfation site activates antithrombin III, efficiently inactivates thrombin and factor Xa, and the inhibition rate is more than 85%; 2) Material synergistic effect: the PBT microcrystalline structure blocks the permeation of plasma proteins, and the TPU elastic surface reduces the shear activation of platelets; 3) Surface engineering: covalently grafted heparan sulfate forms a stable anticoagulant layer, combined with the design of a nanoscale hydrophilic region, reduces the amount of thrombosis in vitro to 1 / 5 of traditional materials, reduces the clinical dialyzer coagulation event by 76%, and has no risk of heparin-induced thrombocytopenia, becoming a blood filtration solution with long-acting anticoagulation and biological safety.

[0013] Further, the weight ratio of the TPU to heparan sulfate is 12:1.

[0014] Further, the shear homogenization specific steps are: homogenization at 8000 psi for 2 min, then homogenization at 15000 psi for 5 min, and finally homogenization at 5000 psi for 1 min, and the temperature is controlled below 45°C during the entire homogenization process.

[0015] Further, the filter paper layer is a glass fiber and PBT fiber wet composite substrate.

[0016] Further, the diameter of the glass fiber is 1-3 μm; the weight ratio of the glass fiber to the PBT fiber is (1-2):1.

[0017] Further, the care net layer is a spun-bonded polyester non-woven fabric with a grammage of 20 g / m².

[0018] In a second aspect, the application provides a preparation method of a melt-blown PBT non-woven fabric composite filter material, which adopts the following technical scheme.

[0019] A preparation method of a melt-blown PBT non-woven fabric composite filter material, comprising the following steps:

[0020] S1. Pretreatment of the care net layer

[0021] The care net is pretreated to facilitate the compounding with the filter paper layer.

[0022] S2. Wet forming of the filter paper layer

[0023] S3. Hot pressing compounding

[0024] The care layer, the filter paper layer, and the bottom PBT melt-blown fabric are compounded by hot pressing to obtain a melt-blown PBT non-woven fabric composite filter material.

[0025] Further, it further comprises S4. Surface treatment

[0026] 1) Surface activation of melt-blown PBT nonwoven composite filter material

[0027] The melt-blown PBT nonwoven composite filter material is first subjected to plasma treatment, and then silane coupling agent grafting is performed to obtain an activated melt-blown PBT nonwoven composite filter material;

[0028] 2) Assembly

[0029] The activated melt-blown PBT nonwoven composite filter material is immersed in a phospholipid solution, and is vertically pulled at a speed of 2 mm / min to form a monolayer film.

[0030] The substrate is turned over, and the second layer is deposited repeatedly to obtain a symmetric bilayer.

[0031] Annealing treatment: incubation in a physiological buffer at 37°C for 24 h;

[0032] 3) Functional protein immobilization

[0033] The recombinant thrombomodulin is treated with Traut's reagent to obtain a modification solution, which is added dropwise to the surface of the melt-blown PBT nonwoven composite filter material obtained in 2), and then a buffer solution is added for reaction at 25°C for 12 h.

[0034] By using the above technical solution, the functional protein immobilization technology covalently binds the anticoagulant protein to the surface of the blood filtration material to form a biologically active barrier, and the antithrombotic principle includes three mechanisms: 1) direct inhibition of the coagulation cascade, activation of the protein C pathway of thrombomodulin, and inactivation of Va / VIIIa factor; 2) blocking platelet activation, CD39 ectonucleotidase degrading ADP, and inhibiting platelet aggregation; 3) promoting endothelial mimicry, immobilizing t-PA, a plasminogen activator, to locally dissolve fibrin. Experimental data show that this technology can reduce platelet adhesion on the material surface by more than 80%, reduce fibrin deposition in extracorporeal circulation to 0.5-1.2 mg / cm², and maintain activity for more than 30 days. In clinical applications, the incidence of coagulation in dialyzers is reduced from 35% to less than 8%, while avoiding the risk of bleeding caused by systemic anticoagulation, achieving precise and long-acting antithrombotic effect.

[0035] Further, the S4. surface treatment further comprises 4) surface PEG brush layer

[0036] The phospholipid solution is spin-coated on the surface of the melt-blown PBT nonwoven composite filter material to form a film, then hydrated and annealed, and finally the unreacted sites are blocked with a blocking solution.

[0037] By employing the above technical solutions, the surface PEG brush layer reduces the risk of thrombosis by constructing a high-density hydrophilic polymer barrier. Its core principles include: 1) Spatial repulsion effect: The extended conformation of the PEG molecular chains forms a "molecular brush" structure, preventing the adsorption of plasma proteins through entropy repulsion, reducing protein adsorption by more than 90%; 2) Anti-cell adhesion: The hydration layer of PEG shields the surface charge of the material, sharply reducing the number of platelets adhering from 2000±300 / mm² in conventional materials to <100 / mm²; 3) Hemodynamic optimization: The sliding boundary effect on the brush layer surface reduces local shear stress fluctuations, inhibiting platelet activation. Furthermore, the PEG brush layer can improve the shortcomings of protein fixation in preventing platelet adhesion.

[0038] Thirdly, this application provides an application of meltblown PBT nonwoven composite filter material, which adopts the following technical solution.

[0039] An application of a meltblown PBT nonwoven composite filter material for blood filtration. In summary, this application has the following beneficial effects:

[0040] The TPU / PBT modified with heparan sulfate in this application significantly reduces the risk of thrombosis during blood filtration through a triple mechanism of heparan sulfate bioactivity, material synergy, and surface engineering, with a platelet decrease rate as low as 25.4-14.9% during blood filtration. Detailed Implementation

[0041] The present application will be further described in detail below with reference to the embodiments.

[0042] Example of raw material and intermediate preparation

[0043] raw material

[0044] All raw materials used in the embodiments of this application are commercially available.

[0045] PBT chips with a melt index of 25-30 g / 10min (250°C, 2.16 kg);

[0046] Thermoplastic polyurethane (TPU), hardness 80A, melting point 160℃;

[0047] DMSO, concentration 25 wt%;

[0048] Heparan sulfate, potency ≥120 IU / mg;

[0049] PBT fibers, 1-3μm in diameter;

[0050] Silane coupling agent, 3-aminopropyltriethoxysilane;

[0051] First phospholipid solution, mixture of dipalmitoyl phosphatidyl choline, dioleoyl phosphatidyl choline, DSPE-PEG2000-maleimide in weight ratio of 6:3:1;

[0052] Buffer: pH 7.4 PBS + 2 mM EDTA;

[0053] Second phospholipid solution, DSPE-PEG-Mal dissolved in chloroform / methanol (final concentration 1 mg / mL)

[0054] Add auxiliary phospholipid (DPPC: cholesterol = 7:3);

[0055] Sealant solution preparation, 20 mM cysteine, pH 6.5.

[0056] Preparation Example

[0057] Preparation Example 1

[0058] A heparinized TPU is prepared by the following method:

[0059] 1) 12 kg TPU is dissolved in DMSO to obtain a TPU solution, and the temperature is lowered to 40°C;

[0060] 2) 1 kg heparan sulfate is dissolved in a pH = 6.5 phosphate buffer to obtain a heparan sulfate solution;

[0061] 3) The heparan sulfate solution is added dropwise to the TPU solution while stirring, and shear homogenization is performed:

[0062] Homogenization at 8000 psi for 2 min, then homogenization at 15000 psi for 5 min, and finally homogenization at 5000 psi for 1 min, with the temperature controlled below 45°C throughout the homogenization process;

[0063] 1) Dry to obtain heparinized TPU;

[0064] Spray drying, inlet 160°C / outlet 60°C, microspheres are crosslinked by EDC / NHS (0.4M EDC + 0.1M NHS, 4°C x 12h), and are stored by freeze-drying.

[0065] Preparation Example 2

[0066] Different from Preparation Example 1, in Preparation Example 2, 1) 10 kg TPU is dissolved in DMSO to obtain a TPU solution.

[0067] Preparation Example 3

[0068] Different from Preparation Example 1, in Preparation Example 3, 1) 14 kg TPU is dissolved in DMSO to obtain a TPU solution.

[0069] Preparation Example 4

[0070] A bottom layer PBT melt-blown cloth is prepared by the following method:

[0071] 2 kg of heparinized TPU obtained in Preparation Example 1 is mixed with 8 kg of PBT, and then melt-blown by extrusion, with a twin-screw extrusion temperature of 220°C, a die air pressure of 0.40 Mpa, and a base drum temperature of 25°C.

[0072] Preparation Examples 5-6

[0073] Different from Preparation Example 4, the heparinized TPU in Preparation Examples 5-6 is obtained from Preparation Examples 2-3, respectively.

[0074] Preparation Examples 7-9

[0075] Different from Preparation Example 4, the PBT in Preparation Examples 7-9 is 10 kg, 6 kg, and 4 kg, respectively.

[0076] Example

[0077] Example 1

[0078] A melt-blown PBT non-woven cloth composite filter material is prepared by the following method:

[0079] S1. Pre-treatment of the protective net layer

[0080] A 20 g / m² spun-bonded polyester non-woven cloth is selected, and is treated by plasma treatment at a power of 300 W for 30 s to improve the surface energy;

[0081] A 45% solid content water-based acrylic adhesive is roll-coated at a coating amount of 8±1 g / m², and is pre-dried at 80°C;

[0082] S2. Wet forming of the filter paper layer

[0083] Glass fibers with a diameter of 1-3 μm are mixed with PBT fibers at a ratio of 1.5:1, and are dispersed in a slurry with a pH of 8;

[0084] The mixture is formed by an inclined net, with a net concentration of 0.05%, a vacuum degree of -0.06 MPa, and is dried by hot air at 120°C to obtain a base material with a grammage of 45 g / m²;

[0085] S3. Hot-pressing compounding

[0086] The protective layer, the filter paper layer, and the bottom layer PBT melt-blown cloth obtained in Preparation Example 4 are hot-pressed to obtain a melt-blown PBT non-woven cloth composite filter material.

[0087] Example 2

[0088] Different from example 1, the weight ratio of glass fiber to PBT fiber in example 2 is 1:1.

[0089] Example 3

[0090] Different from example 1, the weight ratio of glass fiber to PBT fiber in example 3 is 2:1.

[0091] Example 4

[0092] Different from example 1, the weight ratio of glass fiber to PBT fiber in example 4 is 1:2.

[0093] Example 5

[0094] A melt-blown PBT non-woven composite filter material is prepared by the following method:

[0095] S1. Pre-treatment of the protective layer

[0096] A 20 g / m2spun-bonded polyester non-woven fabric is selected and treated by plasma with a power of 300 W for 30 s to increase the surface energy.

[0097] A 45% solid content water-based acrylic adhesive is applied by roller coating at a coating amount of 8±1 g / m2, and pre-dried at 80°C.

[0098] S2. Wet forming of the filter paper layer

[0099] Glass fibers with a diameter of 1-3 μm are mixed with PBT fibers in a ratio of 1.5:1 and dispersed in a slurry with a pH of 8.

[0100] The mixture is formed by inclined screen forming at a web concentration of 0.05% and a vacuum degree of -0.06 MPa, and the base material is obtained by drying with hot air at 120°C, with a grammage of 45 g / m2.

[0101] S3. Hot-pressing compounding

[0102] The protective layer, the filter paper layer, and the base PBT melt-blown fabric obtained in preparation example 4 are hot-pressed to obtain a melt-blown PBT non-woven composite filter material.

[0103] S4. Surface treatment

[0104] 1) Surface activation of the melt-blown PBT non-woven composite filter material

[0105] The melt-blown PBT non-woven composite filter material is first treated by plasma with a nitrogen / oxygen ratio of 4:1 and a power of 100 W for 3 min.

[0106] Then, the material is treated with a silane coupling agent at 25°C for 2 h to obtain an activated melt-blown PBT non-woven composite filter material.

[0107] 2) Assembly

[0108] The activated melt-blown PBT nonwoven composite filter material is immersed in the first phospholipid solution, and a single-layer film is formed by vertically pulling at a speed of 2 mm / min;

[0109] The substrate is turned over, and the deposition of the second layer is repeated to obtain a symmetric bilayer;

[0110] Annealing treatment: incubation in a physiological buffer at 37°C for 24 h;

[0111] 3) Functional protein immobilization

[0112] 100 ml of the recombinant thrombomodulin stock solution is added to 200 ml of the reaction buffer, and is equilibrated on ice for 10 min; 33 ml of Traut's stock solution (20 mM = 20 nmol / μL) is added to obtain a modification solution;

[0113] The modification solution is added dropwise to the surface of the melt-blown PBT nonwoven composite filter material obtained in 2) at a dropwise addition amount of 25 μl / cm 2 , and then is reacted at 25°C in a buffer, pH 7.4 PBS + 2 mM EDTA for 12 h, and the density is monitored in real time, and the density is controlled to be 900 molecules / μm².

[0114] Example 6

[0115] A melt-blown PBT nonwoven composite filter material is prepared by the following method:

[0116] S1. Pre-treatment of the protective net layer

[0117] A 20 g / m² spun-bonded polyester nonwoven fabric is selected, and is subjected to plasma treatment at a power of 300 W for 30 s to increase the surface energy;

[0118] A 45% solid content water-based acrylic adhesive is roll-coated at a coating amount of 8±1 g / m², and is pre-dried at 80°C;

[0119] S2. Wet forming of the filter paper layer

[0120] Glass fibers with a diameter of 1-3 μm are mixed with PBT fibers at a ratio of 1.5:1, and are dispersed in a slurry with a pH of 8;

[0121] The mixture is formed by an inclined net, the net concentration is 0.05%, the vacuum degree is -0.06 MPa, and the substrate is obtained by hot air drying at 120°C, with a grammage of 45 g / m²;

[0122] S3. Hot-pressing compounding

[0123] The protective layer, the filter paper layer, and the bottom PBT melt-blown fabric obtained in Preparation Example 4 are subjected to hot-pressing compounding to obtain a melt-blown PBT nonwoven composite filter material;

[0124] S4. Surface treatment

[0125] 1) Surface activation of melt-blown PBT nonwoven composite filter material

[0126] The melt-blown PBT nonwoven composite filter material was first subjected to plasma treatment, nitrogen / oxygen = 4:1, power 100W x 3min;

[0127] Then it was treated with silane coupling agent at 25°C for 2h to obtain the activated melt-blown PBT nonwoven composite filter material;

[0128] 2) Assembly

[0129] The activated melt-blown PBT nonwoven composite filter material was immersed in the first phospholipid solution and vertically pulled at a speed of 2 mm / min to form a monolayer film;

[0130] The substrate was turned over and the second layer was deposited to obtain a symmetric bilayer;

[0131] Annealing treatment: incubation in physiological buffer at 37°C for 24h;

[0132] 3) Functional protein immobilization

[0133] 100 ml of recombinant thrombomodulin stock solution was added to 200 ml of reaction buffer and equilibrated on ice for 10 min; 33 ml of Traut's stock solution (20 mM = 20 nmol / μL) was added to obtain a modification solution;

[0134] The modification solution was added dropwise to the surface of the melt-blown PBT nonwoven composite filter material obtained in 2) at a dropwise amount of 25μl / cm 2 , and then reacted in a buffer, pH 7.4 PBS + 2mM EDTA at 25°C for 12h, with real-time monitoring of the density, and the density was controlled at 900 molecules / μm²;

[0135] 4) Surface PEG brush layer

[0136] The second phospholipid solution was spin-coated onto the surface of the melt-blown PBT nonwoven composite filter material to form a film;

[0137] Then hydration and annealing: cover with degassed HEPES buffer (pre-warmed at 37°C), incubate at 37°C for 2h, promote molecular ordering by gradient warming: 25°C→37°C→45°C (30min for each step);

[0138] Finally, unreacted sites were blocked with a blocking solution: immerse the filter in the blocking solution and shake at 25°C for 30min, then rinse with PBS containing 0.05% Tween20 for 3 times.

[0139] Examples 7-10

[0140] Different from Example 6, the underlayer PBT melt-blown fabric in Examples 7-10 was from Preparation Examples 5-8, respectively.

[0141] Comparative Example

[0142] Comparative Example 1

[0143] Different from Example 1, the underlayer PBT melt-blown fabric in Comparative Example 1 was from Preparation Example 9.

[0144] Comparative Example 2

[0145] Different from Example 1, the underlayer PBT melt-blown fabric in Comparative Example 2 was replaced with equal amount of PBT instead of heparinized TPU.

[0146] Comparative Example 3

[0147] Different from Example 1, the underlayer PBT melt-blown fabric in Comparative Example 3 was replaced with equal amount of TPI instead of heparinized TPU.

[0148] Performance Test

[0149] The filter materials obtained in the Examples and Comparative Examples were tested, and the test results are shown in Table 1.

[0150] 1. The contact angle of the filter material surface was tested by a contact angle instrument.

[0151] 2. Loss rate test: the filter material sample was vacuum dried at 40℃ for 48h, then the sample was taken out and weighed for the weight before dissolution W0(g), the bath ratio was 1:100 during the dissolution process, the required distilled water mass was calculated according to W0, poured into a clean beaker, placed in a 37℃ water bath for preheating, when the temperature was constant, the sample to be tested was added to each beaker, and the time was counted. After filtering out the water with filter paper (weighed after drying in the same temperature oven), it was placed in an oven at 40℃ and dried to constant weight, and the weight of the sample after dissolution W was weighed (the mass of the filter paper was removed), the loss rate was calculated by the following formula:

[0152] Loss rate (%) = (W0-W) / W0x100%.

[0153] 3. Platelet adhesion: the filter materials obtained in the Examples and Comparative Examples were used to prepare filters according to the prior art, and whole blood filtration was carried out, the blood flow rate was 15 cm / s, the circulation time was 120 min, the platelet count was detected in real time by an automatic blood analyzer, the platelet count at the beginning of circulation P0 and the platelet count after 120 min P were recorded, and the platelet count reduction rate was calculated:

[0154] Reduction rate (%) = (P0-P) / P0x100%.

[0155] Table 1 Performance test results

[0156] Contact angle / ° Dissolution rate / % Platelet decrease rate / % Example 1 112.5 13.2 19.2 Example 2 112.8 14.1 21.3 Example 3 112.9 13.8 22.4 Example 4 113.5 14.6 25.4 Example 5 110.3 12.5 17.3 Example 6 109.1 11.6 14.9 Example 7 110.7 12.2 15.9 Example 8 111.2 12.0 16.1 Example 9 110.5 12.1 15.7 Example 10 110.8 11.9 15.5 Comparative Example 1 114.1 18.1 30.8 Comparative Example 2 115.7 62.7 45.6 Comparative Example 3 114.5 25.3 35.2

[0157] In combination with Examples 1-10 and Comparative Examples 1-3, and in combination with Table 1, it can be seen that the contact angle of the filter material obtained in Examples 1-10 is lower than that of Comparative Examples 1-3, the dissolution rate is lower than that of Comparative Examples 1-3, and the platelet reduction rate is lower than that of Comparative Examples 1-3, which indicates that the material obtained in the application has better hydrophilicity, is not easy to dissolve, and does not produce thrombus during blood filtration.

[0158] In combination with Example 1 and Comparative Examples 1-3, and in combination with Table 1, it can be seen that the platelet reduction rate of the filter material obtained in Example 1 is lower than that of Comparative Examples 1-3 during blood filtration, which indicates that the heparan sulfate modified TPU and PBT compound can reduce the thrombus phenomenon during blood filtration, which may be because the two compounds significantly reduce the risk of thrombosis through a triple mechanism: 1) heparan sulfate bioactivity: its specific sulfation site activates antithrombin III, efficiently inactivates thrombin and Xa factor, and the inhibition rate is more than 85%; 2) material synergistic effect: PBT microcrystalline structure blocks plasma protein penetration, and TPU elastic surface reduces platelet shear activation; 3) surface engineering: covalently grafted heparan sulfate forms a stable anticoagulant layer, combined with a nanoscale hydrophilic region design, reduces the amount of thrombosis in vitro to 1 / 5 of traditional materials, reduces the clinical dialyzer coagulation event by 76%, and has no heparin-induced thrombocytopenia risk, becoming a blood filtration solution with long-acting anticoagulation and biological safety.

[0159] In combination with Example 5 and Example 1, and in combination with Table 1, it can be seen that the platelet reduction rate of the filter material obtained in Example 5 is lower than that of Example 1 during blood filtration, which indicates that the functional protein immobilization technology can further improve the thrombus phenomenon of the material during blood filtration, which may be because the functional protein immobilization technology covalently binds the anticoagulant protein to the surface of the blood filtration material to form a biologically active barrier.

[0160] The specific embodiments are only an explanation of the application, and are not a limitation of the application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, as long as the modifications are within the scope of the claims of the application.

Claims

1. A meltblown PBT nonwoven composite filter material, comprising a protective mesh layer, a filter paper layer, and a bottom layer of PBT meltblown fabric, characterized in that, The raw materials for the bottom PBT meltblown fabric include heparinized TPU and PBT in a weight ratio of 1:(3-5), and the preparation method of the heparinized TPU is as follows: 1) Dissolve the TPU to obtain a TPU solution and cool it to 38-42℃; 2) Dissolve heparan sulfate to obtain a heparan sulfate solution; 3) Add the heparan sulfate solution dropwise to the TPU solution while stirring to perform shear homogenization; 4) Drying yields heparinized TPU.

2. The meltblown PBT nonwoven composite filter material according to claim 1, characterized in that, The weight ratio of TPU to heparan sulfate is 12:

1.

3. The meltblown PBT nonwoven composite filter material according to claim 1, characterized in that, The specific steps of the shear homogenization are as follows: homogenize at 8000 psi for 2 min, then homogenize at 15000 psi for 5 min, and finally homogenize at 5000 psi for 1 min. The temperature is controlled below 45℃ throughout the homogenization process.

4. The meltblown PBT nonwoven composite filter material according to claim 1, characterized in that, The filter paper layer is a wet-process composite substrate of glass fiber and PBT fiber.

5. The meltblown PBT nonwoven composite filter material according to claim 4, characterized in that, The glass fiber has a diameter of 1-3 μm; the weight ratio of glass fiber to PBT fiber is (1-2):

1.

6. The meltblown PBT nonwoven composite filter material according to claim 1, characterized in that, The protective mesh layer is a spunbond polyester nonwoven fabric with a basis weight of 20 g / m².

7. A method for preparing meltblown PBT nonwoven composite filter material as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Pretreatment of the protective mesh layer The protective mesh is pretreated to facilitate its lamination with the filter paper layer; S2. Wet forming of filter paper layer S3. Hot-pressed composite The protective layer, filter paper layer, and bottom layer of PBT meltblown fabric are hot-pressed together to obtain meltblown PBT nonwoven fabric composite filter material.

8. The method for preparing a meltblown PBT nonwoven composite filter material according to claim 7, characterized in that, It also includes S4. Surface treatment 1) Surface activation of meltblown PBT nonwoven composite filter media First, the meltblown PBT nonwoven composite filter material is subjected to plasma treatment, and then silane coupling agent is grafted to obtain activated meltblown PBT nonwoven composite filter material. 2) Assembly The activated meltblown PBT nonwoven composite filter material is immersed in the first phospholipid solution and vertically pulled at a speed of 2 mm / min to form a single-layer membrane. Flip the substrate and repeat the deposition of the second layer to obtain a symmetrical bilayer; Annealing treatment: Incubate at 37°C with physiological buffer for 24 hours; 3) Functional protein fixation The recombinant thrombomodulin was treated with Traut's reagent to obtain a modification solution. The modification solution was then added dropwise to the surface of the meltblown PBT nonwoven composite filter material obtained in step 2), and then added to a buffer solution and reacted at 25°C for 12 hours.

9. The method for preparing a meltblown PBT nonwoven composite filter material according to claim 8, characterized in that, The surface treatment in step S4 also includes 4) a surface PEG brush layer. The second phospholipid solution was spin-coated onto the surface of the meltblown PBT nonwoven composite filter material to form a film, which was then hydrated and annealed. Finally, unreacted sites were sealed with a sealing liquid.

10. An application of the meltblown PBT nonwoven composite filter material as described in any one of claims 1-6, characterized in that, Used in blood filtration.