High water-absorbing antibacterial absorbent core for elastic film pull-up diaper and preparation method thereof

Abstract

The application discloses a high-water-absorption antibacterial absorbent core for elastic film pull-on pants, which is prepared from the following components in parts by weight: 20-40 parts of high-water-absorption resin, 6-12 parts of modified polyacrylonitrile fiber and 10-20 parts of sericin protein solution; the modified polyacrylonitrile fiber is obtained by modifying polyacrylonitrile fiber after alkali treatment, and by using m-phenylenediamine-4-sodium sulfonate and 1H-pyrazole-1-carbamidine hydrochloride; the high-water-absorption antibacterial absorbent core prepared by the application not only remarkably improves the absorption speed and water-locking capacity, but also endows the product with the health safety attribute of active antibiosis, thereby bringing the user a more dry, comfortable and reassuring use experience, and the product has a remarkable market competitive advantage.

Description

Technical Field

[0001] This invention relates to the field of pull-up pants technology, specifically to a highly absorbent and antibacterial core for elastic membrane pull-up pants and its preparation method. Background Technology

[0002] The absorbent core is the core functional component of disposable hygiene products such as diapers, pull-ups, and sanitary napkins. Its performance directly determines the product's absorption speed, absorbency, water retention, and ultimately, user comfort. Currently, mainstream absorbent cores on the market typically employ a composite structure made by mixing and pressing superabsorbent polymer (SAP) particles with fluff pulp fibers. The fluff pulp primarily serves to build the framework, channel liquid, and support the SAP particles, while the SAP itself is responsible for absorbing and storing large amounts of liquid.

[0003] However, this traditional fluff pulp / SAP composite core has many inherent drawbacks in practical applications. First, the wet strength of fluff pulp fibers is low, and their structure becomes loose or even destroyed after absorbing liquid, leading to clumping, breakage, and pilling in the core. This not only severely affects the secondary absorption and diffusion capacity of liquids, reducing the effective utilization rate of SAP, but also significantly reduces wearing comfort and may even cause side leakage and backflow problems. Second, fluff pulp itself does not have antibacterial properties. After absorbing urine and other bodily fluids, the warm and humid internal environment of the core easily becomes a breeding ground for bacteria (such as Staphylococcus aureus and Escherichia coli). The rapid proliferation of bacteria not only decomposes urea to produce ammonia, causing an unpleasant odor, but also leads to an increase in local pH, irritating the delicate skin of infants and increasing the risk of diaper rash.

[0004] To address the aforementioned issues, several improvements have been proposed in the prior art. For example, the structural stability of the core can be improved by using hot-air nonwoven fabric or chemical adhesives, but this often increases the stiffness of the core, sacrificing softness and comfort, and may introduce potential chemical irritants.

[0005] CN117883625A discloses a highly efficient odor-removing and antibacterial diaper core material and its preparation process, comprising the following components in parts by weight: 0.001-3.5 parts by weight of humidity regulator, 0.05-1.2 parts by weight of antibacterial agent, 30-45 parts by weight of absorbent resin, 1.5-2.5 parts by weight of aloe vera gel, 1.5-2.5 parts by weight of deodorant, 50-65 parts by weight of fiber material, 0.3-0.8 parts by weight of hot-melt urine indicator adhesive, and 1-3 parts by weight of pearl powder. The antibacterial agent is chitosan or Artemisia argyi extract. However, these antibacterial agents are mostly added later as free components, which may migrate with the liquid flow, resulting in a short-lasting antibacterial effect and a potential risk of leaching from the product, contact with the skin, and causing allergies or safety issues.

[0006] Therefore, developing a new type of absorbent core that can maintain excellent absorbency and water retention performance, possess long-lasting and safe intrinsic antibacterial function, and maintain good structural integrity and softness and comfort even when wet is a technical challenge that urgently needs to be solved in the current hygiene products field. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a highly absorbent and antibacterial core for elastic membrane pull-up pants and its preparation method. By scientifically compounding and integrally molding functional modified polyacrylonitrile fibers, superabsorbent resin and natural sericin adhesive, the technical pain points of traditional cores that are prone to clumping, backflow and bacterial growth after absorbing liquid are solved.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A superabsorbent and antibacterial core for elastic membrane pull-up pants is made of the following components by weight: 20-40 parts superabsorbent resin, 6-12 parts modified polyacrylonitrile fiber, and 10-20 parts sericin solution.

[0010] Preferably, the sericin solution is a PVA solution of sericin with a concentration of 10-15 wt%.

[0011] Preferably, the modified polyacrylonitrile fiber is prepared by the following method steps:

[0012] (1) Disperse polyacrylonitrile fibers in sodium hydroxide solution, reflux the reaction, filter, wash and dry the product to obtain pretreated fibers;

[0013] Alkaline hydrolysis: The cyano groups (-CN) on the surface of polyacrylonitrile fibers undergo nucleophilic hydrolysis under strongly alkaline conditions of sodium hydroxide. Hydroxide ions first attack the carbon atom in the cyano group, forming a hydroxyimine intermediate, which then rearranges with the participation of water molecules to form an amide group (-CONH2). Some of the amide groups continue to hydrolyze under prolonged strongly alkaline conditions, resulting in the removal of the amino group to form a carboxyl group (-COOH), thereby changing the fiber surface from hydrophobic to hydrophilic and providing active groups for subsequent reactions.

[0014] Preferably, in step (1), the ratio of polyacrylonitrile fiber to sodium hydroxide solution is 10g: 300-500mL; the concentration of sodium hydroxide solution is 1-5mol / L.

[0015] Preferably, in step (1), the reflux reaction conditions are 80-95℃, 200-400r / min for 7-10h, and the pH of the system is maintained at 12-14 during the reaction.

[0016] (2) The pretreated fiber was dispersed in phosphate buffer, sonicated, and then EDC·HCl and NHS were added. The fiber was activated at room temperature, and then sodium m-phenylenediamine-4-sulfonate was added. The mixture was stirred and reacted. The product was filtered, washed and dried to obtain intermediate fiber.

[0017] EDC / NHS Coupling Reaction: The carboxyl groups on the pretreated fiber surface are activated by EDC·HCl, forming an O-acylurea reactive intermediate. NHS then reacts with this intermediate to generate a more stable NHS reactive ester. The amino group in the sodium m-phenylenediamine-4-sulfonate molecule acts as a nucleophile, attacking the carbonyl carbon atom in the NHS reactive ester, forming a stable amide bond through a nucleophilic acyl substitution reaction, while simultaneously releasing NHS molecules. This process successfully covalently links sodium m-phenylenediamine-4-sulfonate, containing sulfonic acid groups and a free amino group, to the fiber surface, introducing the desired functional groups.

[0018] Preferably, in step (2), the ratio of pretreated fiber, phosphate buffer, EDC·HCl, NHS, and sodium m-phenylenediamine-4-sulfonate is 10g:300~500mL:4~6g:2~3g:4~7g, and the pH of the phosphate buffer is 6.5~7.

[0019] Preferably, in step (2), the ultrasonic treatment lasts for 20 to 40 minutes; the activation at room temperature lasts for 40 to 60 minutes; and the stirring reaction conditions are 30 to 45°C with gentle stirring for 14 to 20 hours.

[0020] (3) Disperse the intermediate fiber into DMF, add triethylamine under nitrogen atmosphere, add 1H-pyrazole-1-formamidine hydrochloride under stirring, stir the reaction, filter, wash and dry the product to obtain modified polyacrylonitrile fiber.

[0021] Guanidinization reaction: Triethylamine first undergoes an acid-base reaction with 1H-pyrazole-1-formamidinium hydrochloride, neutralizing the hydrochloric acid to generate a free pyrazole-formamidinium group. The residual amino group on the intermediate fiber surface acts as a nucleophile, attacking the imine carbon atom in the formamidinium group, forming a stable guanidinium structure (-NH-C(=NH)-pyrazole) through a nucleophilic addition reaction. This reaction is carried out under the basic catalysis of triethylamine, successfully introducing the pyrazole-formamidinium group into the fiber surface, completing the entire modification process.

[0022] Preferably, in step (3), the ratio of intermediate fiber, DMF, triethylamine, and 1H-pyrazole-1-formamidinium hydrochloride is 10g: 300-500mL: 6-9mL: 6-9g.

[0023] Preferably, in step (3), the stirring reaction conditions are 50-65°C for 10-16 hours, and the product is washed 2-3 times with DMF, anhydrous ethanol and deionized water in sequence.

[0024] This invention also claims a method for preparing the superabsorbent and antibacterial absorbent core for elastic membrane pull-up pants, comprising the following steps: mixing superabsorbent resin, modified polyacrylonitrile fiber, and sericin solution evenly and soaking for 3-6 hours, extruding and granulating, drying and then coating and bonding, compacting and cutting to obtain the superabsorbent and antibacterial absorbent core.

[0025] The present invention also claims the application of the aforementioned highly absorbent and antibacterial core in elastic membrane pull-up pants, characterized in that the elastic membrane pull-up pants include a front waistband, a core, and a back waistband, with the opposite ends of the core being fixedly connected to the front waistband and the back waistband respectively, and an elastic membrane being fixedly connected to the front waistband, the elastic membrane extending along the length direction of the core; and adhesive pieces being provided at the opposite ends of the back waistband, the adhesive pieces being pasted onto the elastic membrane.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. This invention provides a highly absorbent and antibacterial core for elastic membrane pull-up pants, possessing multiple advantages such as rapid liquid absorption, strong water retention, antibacterial safety, and structural stability. Firstly, the components work synergistically. Superabsorbent polymer (SAP), as the core absorbent component, provides a huge liquid absorption capacity and excellent water retention performance. The modified polyacrylonitrile fiber prepared in this invention has abundant hydrophilic groups on its surface, constructing a highly efficient flow-guiding network that can quickly guide liquid diffusion and absorption by SAP, effectively preventing backflow and side leakage. Sericin, as a natural polymeric adhesive, not only ensures tight adhesion between SAP and fiber, forming a stable core structure that is not easily broken or clumped, but also enhances the comfort and safety of the product due to its good biocompatibility and skin-friendliness. Secondly, the preparation method of this invention is scientifically sound. Through processes such as mixing and soaking, extrusion granulation, and drying coating, the components are evenly distributed, resulting in a complete core structure with uniform density, thus guaranteeing its stability and absorption performance in actual use.

[0028] 2. This invention provides a method for preparing modified polyacrylonitrile fibers. The first step, alkaline hydrolysis, converts the inherent hydrophobic cyano groups on the surface of the polyacrylonitrile fibers into hydrophilic carboxyl and amide groups. This not only greatly improves the wettability and water absorption capacity of the fibers but also introduces the necessary elements for subsequent grafting reactions. The second step, an EDC / NHS coupling reaction, utilizes the carboxyl groups introduced in the first step to successfully graft sodium m-phenylenediamine-4-sulfonate. This not only introduces strongly hydrophilic sulfonic acid groups, further enhancing the fiber's moisture absorption and water retention capacity, but also introduces free amino groups, providing new active sites for the third step reaction. The third step, a guanidinolation reaction, covalently links the pyrazole formamidinium group, which has broad-spectrum and highly efficient antibacterial activity, to the fiber surface via stable CN bonds, endowing the fibers with durable and safe antibacterial properties, effectively inhibiting bacterial growth and reducing odor generation. In summary, this ingenious multi-step modification strategy makes the final fiber combine rapid flow conduction, high moisture absorption, and strong antibacterial properties, making it an ideal material for high-performance absorbent cores. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0030] Unless otherwise specified, all chemical reagents and materials in this invention are purchased from the market or synthesized from raw materials purchased from the market.

[0031] The superabsorbent resin can be a commercially available product. The preparation method of the superabsorbent resin used in the embodiments and comparative examples of this invention is as follows: 15 parts of acrylic acid, 20 parts of acrylamide and 15 parts of chitosan are stirred evenly at 70°C, and then 3 parts of ammonium persulfate initiator, 6 parts of benzoyl peroxide crosslinking agent and 15 parts of acrylic acid are added in sequence and stirred for 2 hours. After stirring, it is mixed with 30 parts of starch and stirred evenly for 1.5 hours. After sieving, it is dried and granulated to obtain the superabsorbent resin.

[0032] A method for preparing a highly absorbent and antibacterial core for elastic membrane pull-up pants includes the following steps:

[0033] (1) Disperse 10g of polyacrylonitrile fiber into 300-500mL of 1-5mol / L sodium hydroxide solution, reflux at 80-95℃ and 200-400r / min for 7-10h, and keep the pH of the system at 12-14 during the reaction. Filter, wash and dry the product to obtain pretreated fiber.

[0034] (2) Disperse 10g of pretreated fiber into 300-500mL of phosphate buffer (pH=6.5-7), sonicate for 20-40min, then add 4-6g of EDC·HCl and 2-3g of NHS, activate at room temperature for 40-60min, then add 4-7g of sodium m-phenylenediamine-4-sulfonate, stir gently at 30-45℃ for 14-20h, filter, wash and dry the product to obtain intermediate fiber;

[0035] (3) Disperse 10g of intermediate fiber into 300-500mL of DMF, add 6-9mL of triethylamine under a nitrogen atmosphere, add 6-9g of 1H-pyrazole-1-formamidin hydrochloride while stirring, stir and react at 50-65℃ for 10-16h, filter the product, wash it 2-3 times with DMF, anhydrous ethanol and deionized water in sequence, and dry it to obtain modified polyacrylonitrile fiber;

[0036] (4) Mix 20-40 parts of superabsorbent resin, 6-12 parts of modified polyacrylonitrile fiber, and 10-20 parts of PVA solution containing 10-15 wt% sericin evenly, soak for 3-6 hours, extrude and granulate, dry, coat and bond, compact and cut to obtain the superabsorbent antibacterial absorbent core.

[0037] The present invention will be further described below through specific embodiments.

[0038] Example 1

[0039] A method for preparing a highly absorbent and antibacterial core for elastic membrane pull-up pants includes the following steps:

[0040] (1) Disperse 10g of polyacrylonitrile fiber into 400mL of 3mol / L sodium hydroxide solution and reflux at 95℃ and 300r / min for 7h. During the reaction, keep the pH of the system at 13. Filter, wash and dry the product to obtain pretreated fiber.

[0041] (2) Disperse 10g of pretreated fiber into 400mL of phosphate buffer (pH=6.5), sonicate for 30min, then add 6g of EDC·HCl and 3g of NHS, activate at room temperature for 50min, then add 7g of sodium m-phenylenediamine-4-sulfonate, stir gently at 45℃ for 14h, filter, wash and dry the product to obtain intermediate fiber;

[0042] (3) Disperse 10g of intermediate fiber into 400mL of DMF, add 9mL of triethylamine under nitrogen atmosphere, add 9g of 1H-pyrazole-1-formamidin hydrochloride under stirring, stir and react at 65℃ for 10h, filter the product, wash twice with DMF, anhydrous ethanol and deionized water in sequence, and dry to obtain modified polyacrylonitrile fiber.

[0043] (4) Mix 4000g of superabsorbent resin, 1200g of modified polyacrylonitrile fiber and 2000g of 15wt% sericin PVA solution evenly and soak for 5h. Then, granulate by extrusion, dry and coat and bond, compact and cut to obtain the superabsorbent antibacterial absorbent core.

[0044] Example 2

[0045] A method for preparing a highly absorbent and antibacterial core for elastic membrane pull-up pants includes the following steps:

[0046] (1) Disperse 10g of polyacrylonitrile fiber into 400mL of 3mol / L sodium hydroxide solution, reflux at 90℃ and 300r / min for 8h, and keep the pH of the system at 13 during the reaction. Filter, wash and dry the product to obtain pretreated fiber.

[0047] (2) Disperse 10g of pretreated fiber into 400mL of phosphate buffer (pH=6.5), sonicate for 30min, then add 5g of EDC·HCl and 2.5g of NHS, activate at room temperature for 50min, then add 6g of sodium m-phenylenediamine-4-sulfonate, stir gently at 40℃ for 16h, filter, wash and dry the product to obtain intermediate fiber;

[0048] (3) Disperse 10g of intermediate fiber into 400mL of DMF, add 8mL of triethylamine under nitrogen atmosphere, add 8g of 1H-pyrazole-1-formamidine hydrochloride under stirring, stir and react at 60℃ for 12h, filter the product, wash twice with DMF, anhydrous ethanol and deionized water in sequence, and dry to obtain modified polyacrylonitrile fiber.

[0049] (4) Mix 3500g of superabsorbent resin, 1000g of modified polyacrylonitrile fiber and 1600g of 15wt% sericin PVA solution evenly and soak for 5h. Then, granulate by extrusion, dry and coat and bond, compact and cut to obtain the superabsorbent antibacterial absorbent core.

[0050] Example 3

[0051] A method for preparing a highly absorbent and antibacterial core for elastic membrane pull-up pants includes the following steps:

[0052] (1) Disperse 10g of polyacrylonitrile fiber into 400mL of 3mol / L sodium hydroxide solution and reflux at 85℃ and 300r / min for 9h. During the reaction, keep the pH of the system at 13. Filter, wash and dry the product to obtain pretreated fiber.

[0053] (2) Disperse 10g of pretreated fiber into 400mL of phosphate buffer (pH=6.5), sonicate for 30min, then add 5g of EDC·HCl and 2.5g of NHS, activate at room temperature for 50min, then add 6g of sodium m-phenylenediamine-4-sulfonate, stir gently at 35℃ for 18h, filter, wash and dry the product to obtain intermediate fiber;

[0054] (3) Disperse 10g of intermediate fiber into 400mL of DMF, add 7mL of triethylamine under nitrogen atmosphere, add 7g of 1H-pyrazole-1-formamidin hydrochloride under stirring, stir and react at 55℃ for 14h, filter the product, wash twice with DMF, anhydrous ethanol and deionized water in sequence, and dry to obtain modified polyacrylonitrile fiber.

[0055] (4) Mix 2500g of superabsorbent resin, 800g of modified polyacrylonitrile fiber and 1400g of 15wt% sericin PVA solution evenly and soak for 5h. Then, extrude and granulate, dry and coat and bond, compact and cut to obtain the superabsorbent antibacterial absorbent core.

[0056] Example 4

[0057] A method for preparing a highly absorbent and antibacterial core for elastic membrane pull-up pants includes the following steps:

[0058] (1) Disperse 10g of polyacrylonitrile fiber into 400mL of 3mol / L sodium hydroxide solution, reflux at 80℃ and 300r / min for 10h, and keep the pH of the system at 13 during the reaction. Filter, wash and dry the product to obtain pretreated fiber.

[0059] (2) Disperse 10g of pretreated fiber into 400mL of phosphate buffer (pH=6.5), sonicate for 30min, then add 4g of EDC·HCl and 2g of NHS, activate at room temperature for 50min, then add 4g of sodium m-phenylenediamine-4-sulfonate, stir gently at 30℃ for 20h, filter, wash and dry the product to obtain intermediate fiber;

[0060] (3) Disperse 10g of intermediate fiber into 400mL of DMF, add 6mL of triethylamine under nitrogen atmosphere, add 6g of 1H-pyrazole-1-formamidin hydrochloride under stirring, stir and react at 50℃ for 16h, filter the product, wash twice with DMF, anhydrous ethanol and deionized water in sequence, and dry to obtain modified polyacrylonitrile fiber.

[0061] (4) Mix 2000g of superabsorbent resin, 600g of modified polyacrylonitrile fiber and 1000g of 15wt% sericin PVA solution evenly and soak for 5h. Then, extrude and granulate, dry and coat and bond, compact and cut to obtain the superabsorbent antibacterial absorbent core.

[0062] Comparative Example 1

[0063] A method for preparing a highly absorbent and antibacterial core for elastic membrane pull-up pants includes the following steps:

[0064] (1) Disperse 10g of polyacrylonitrile fiber into 400mL of 3mol / L sodium hydroxide solution and reflux at 95℃ and 300r / min for 7h. During the reaction, keep the pH of the system at 13. Filter, wash and dry the product to obtain pretreated fiber.

[0065] (2) Disperse 10g of pretreated fiber into 400mL of phosphate buffer (pH=6.5), sonicate for 30min, then add 6g of EDC·HCl and 3g of NHS, activate at room temperature for 50min, then add 7g of sodium m-phenylenediamine-4-sulfonate, stir gently at 45℃ for 14h, filter, wash and dry the product to obtain intermediate fiber;

[0066] (3) Mix 4000g of superabsorbent resin, 1000g of intermediate fiber, 200g of 1H-pyrazole-1-formamidin hydrochloride and 2000g of 15wt% sericin PVA solution evenly and soak for 5h. Then, granulate by extrusion, dry and coat and bond, compact and cut to obtain the superabsorbent antibacterial absorbent core.

[0067] Comparative Example 2

[0068] A method for preparing a highly absorbent and antibacterial core for elastic membrane pull-up pants includes the following steps:

[0069] (1) Disperse 10g of polyacrylonitrile fiber into 400mL of 3mol / L sodium hydroxide solution and reflux at 95℃ and 300r / min for 7h. During the reaction, keep the pH of the system at 13. Filter, wash and dry the product to obtain pretreated fiber.

[0070] (2) Mix 4000g of superabsorbent resin, 1000g of pretreated fiber, 200g of sodium m-phenylenediamine-4-sulfonate, and 2000g of 15wt% sericin PVA solution evenly and soak for 5h. Then, granulate by extrusion, dry and coat and bond, compact and cut to obtain the superabsorbent antibacterial absorbent core.

[0071] The performance of the absorber cores prepared in Examples 1-4 and Comparative Examples 1-2 was tested.

[0072] (1) Liquid absorption ratio test: The tea bag method was used. 1g of absorbent core was weighed and placed in a tea bag, which was then immersed in the liquid. After sufficient liquid absorption and equilibrium, the core was suspended and left to stand for 30 minutes to remove any unabsorbed liquid. The absorbent core was then weighed. The liquid absorption ratio was calculated using the formula Q = (m1 - m2) / m2, where m1 is the mass of the absorbent core after absorption and m2 is the original mass of the absorbent core. The arithmetic mean of three measurements was taken as the measurement result, and the data results are shown in Table 1. The liquids used were Wahaha purified water, a 0.9% w / v sodium chloride purified water solution, and artificial urine (a purified water solution containing 2% w / v urea, 1% w / v sodium chloride, 0.05% w / v calcium chloride, and 0.1% w / v magnesium sulfate).

[0073] (2) Absorption rate test: Take 50 mL of pure water into a beaker, put a magnetic rotor into the beaker, place it on a magnetic stirrer, adjust the speed to 600 r / min, add 2 g of absorption core into the vortex, and the vortex begins to disappear while absorbing pure water. The time required to reach stillness on the liquid surface is the absorption rate. The data results are shown in Table 1.

[0074] (3) Reverse osmosis test: After absorbing pure water for 1 hour, the absorbent core was placed at 25℃ and 70% (relative humidity). A filter paper was placed on its surface and its mass was recorded as m1. A 250g weight was used to press it down for 6 hours. After 6 hours, the weight of the filter paper was measured as m2. The reverse osmosis was calculated as m2-m1. The data results are shown in Table 1.

[0075] (4) Antibacterial test: Designed according to ISO 22196:2011, the bacterial strains were Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922). The two strains were spread and inoculated on LB agar plates. About 0.1g of absorbent core sample was crushed and pressed into a nearly circular piece with a diameter of about 1cm. After sterilization by irradiation with ultraviolet light for 3 minutes, it was placed in the center of the plate. After incubation at 37℃ for 24h, the diameter of the inhibition zone was measured. The average of 3 parallel experiments was taken and the data results are shown in Table 1.

[0076] Table 1. Test results of absorber core performance

[0077]

[0078] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A highly absorbent and antibacterial core for elastic membrane pull-up pants, characterized in that, It is made of the following components in parts by weight: 20-40 parts superabsorbent resin, 6-12 parts modified polyacrylonitrile fiber, and 10-20 parts sericin solution; The modified polyacrylonitrile fiber is prepared by the following method steps: (1) Disperse polyacrylonitrile fibers in sodium hydroxide solution, reflux the reaction, filter, wash and dry the product to obtain pretreated fibers; (2) The pretreated fiber was dispersed in phosphate buffer, sonicated, and then EDC·HCl and NHS were added. The fiber was activated at room temperature, and then sodium m-phenylenediamine-4-sulfonate was added. The reaction was stirred, and the product was filtered, washed, and dried to obtain intermediate fiber. (3) Disperse the intermediate fiber into DMF, add triethylamine under nitrogen atmosphere, add 1H-pyrazole-1-formamidine hydrochloride under stirring, stir the reaction, filter, wash and dry the product to obtain modified polyacrylonitrile fiber.

2. The super absorbent and antibacterial core according to claim 1, characterized in that, In step (1), the ratio of polyacrylonitrile fiber to sodium hydroxide solution is 10g: 300~500mL; the concentration of sodium hydroxide solution is 1~5mol / L.

3. The super absorbent and antibacterial core according to claim 1, characterized in that, In step (1), the reflux reaction conditions are 80~95℃, 200~400r / min for 7~10h, and the pH of the system is maintained at 12~14 during the reaction.

4. The super absorbent and antibacterial core according to claim 1, characterized in that, In step (2), the ratio of pretreated fiber, phosphate buffer, EDC·HCl, NHS, and sodium m-phenylenediamine-4-sulfonate is 10g: 300~500mL: 4~6g: 2~3g: 4~7g, and the pH of the phosphate buffer is 6.5~7.

5. The superabsorbent and antibacterial absorbent core according to claim 1, characterized in that, In step (2), ultrasonic treatment is performed for 20-40 min; activation is performed at room temperature for 40-60 min; and the stirring reaction is carried out at 30-45℃ with gentle stirring for 14-20 h.

6. The superabsorbent and antibacterial core according to claim 1, characterized in that, In step (3), the ratio of intermediate fiber, DMF, triethylamine, and 1H-pyrazole-1-formamidin hydrochloride is 10g: 300~500mL: 6~9mL: 6~9g.

7. The superabsorbent and antibacterial absorbent core according to claim 1, characterized in that, In step (3), the stirring reaction conditions are 50~65℃ for 10~16h, and the product is washed 2~3 times with DMF, anhydrous ethanol and deionized water in sequence.

8. The superabsorbent and antibacterial core according to claim 1, characterized in that, The sericin solution is a PVA solution of sericin with a concentration of 10-15 wt%.

9. A method for preparing a highly absorbent and antibacterial core for elastic membrane pull-up pants as described in any one of claims 1 to 8, characterized in that, The process includes the following steps: mixing superabsorbent resin, modified polyacrylonitrile fiber, and sericin solution evenly and soaking for 3-6 hours, extruding and granulating, drying and then coating and bonding, compacting and cutting to obtain the superabsorbent and antibacterial absorbent core.

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