Preparation method of composite fiber blanket

Abstract

The invention discloses a preparation method of a composite fiber blanket, belongs to the technical field of blanket preparation, and is used for solving the technical problem that the heat preservation and moisture permeability and the mechanical property of a fiber blanket in the prior art need to be further improved. Polyphenol-polyamide copolymer fibers and PBS grafted composite fibers are used as a framework and matched with a hybrid functional sizing agent to prepare the composite fiber blanket, the polyphenol-polyamide copolymer fibers are subjected to Schiff base-interfacial polycondensation-drafting shaping to form a stable and fluffy structure, and the PBS grafted composite fibers are subjected to melt grafting and ring opening to endow polarity and resilience. The hybrid functional sizing agent forms a film at the junction with silane sol-gel through epoxy ring opening, so that heat flow path extension, rapid moisture diffusion and effective load transfer are integrally realized, the thermal resistance is improved, the moisture resistance is reduced, the breaking strength and the elongation are synchronously improved, and the hybrid functional sizing agent is suitable for being applied to the warm-keeping blanket.

Description

Technical Field

[0001] This invention relates to the field of blanket manufacturing technology, and specifically to a method for preparing a composite fiber blanket. Background Technology

[0002] In recent years, composite fiber blankets have evolved from "single material + uniform fluffiness" to "multi-material superposition + pore size gradient" in terms of heat preservation and moisture permeability: ultrafine, hollow and irregular cross-section fibers are widely used, and bicomponent skin-core fibers are used to create a stable air layer; in terms of structure, multi-layer sandwich and thickness-oriented interconnected channels are explored, and hydrophilic / hydrophobic partitioning, surface energy regulation, phase change microcapsules or aerogel coating are used to achieve a smoother heat transfer path between thickness, heat preservation and water vapor diffusion. In terms of mechanical performance, the process has expanded from simple needle punching to various consolidation methods such as hot air spot bonding, composite hot pressing, and warp-knitted mesh reinforcement; on the material side, it has transitioned from conventional polyester / acrylic to low-melting-point or sheath-core bicomponent fibers, grafted modified polyester, and functional sizing and coupling agents to improve the load transfer between fibers and washability; at the same time, by combining stretching orientation and heat setting, and utilizing the path of three-dimensional entanglement and local spot bonding, the overall stability of strength, resilience and hand feel is taken into account.

[0003] Existing composite fiber blankets often present a trade-off between heat preservation and moisture permeability: in order to pursue thermal resistance, the weight is generally increased, the thickness is thickened, or a high-adhesion resin is used for the surface covering, which easily creates "thermal bridges" and covers the pores. Although the static air layer is fixed, the water vapor diffusion path is lengthened and the tortuosity is increased. In a humid and hot environment, moisture is retained and the drying recovery is slow. After repeated compression or washing, the fluffy layer is prone to collapse, and the thickness and microporous structure are difficult to maintain, and the thermal resistance decreases accordingly. In terms of mechanical performance, single needle punching or single thermal bonding methods result in discontinuous load transfer, limited interfiber friction-locking, and limited improvement in grip strength and tear strength. To compensate for the lack of strength, high-solids coatings or base fabric reinforcement are often introduced, but this leads to a chain reaction of effects such as hardening of the hand feel, poor dimensional resilience, and impeded moisture permeability. Interface modification is mostly limited to physical film formation, which is prone to fatigue cracking after washing and shear transfer attenuation, resulting in insufficient strength retention and service durability.

[0004] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing composite fiber blankets, which solves the technical problem that the heat insulation and moisture permeability, as well as the mechanical properties of existing fiber blankets, need to be further improved.

[0006] The objective of this invention can be achieved through the following technical solutions: A method for preparing a composite fiber blanket includes the following steps: S1. Weigh out 6 parts of polyphenol-polyamide copolymer fiber and 4-5 parts of PBS grafted composite fiber by weight, open and mix them, humidify them at 20-24℃ and 55-65%RH for 4-6 hours, comb and cross-lay the fiber web to the target weight to form a fiber web, and then needle punch to obtain a pre-cured blanket. S2. Weigh out 20 parts by volume of hybrid functional sizing agent, 4 parts by volume of anhydrous ethanol and 1 part by volume of deionized water and add them to the reaction vessel and stir. Adjust the pH of the system to 5.0 with glacial acetic acid to obtain sizing solution. Use the sizing solution to perform two dips and two nips on the pre-cured blanket, controlling the nips ratio to 60-80%. The post-treatment yields the composite fiber blanket.

[0007] The principle of preparing composite fiber blankets is as follows: During the needle-punching process, polyphenol-polyamide copolymer fibers and PBS-grafted composite fibers undergo three-dimensional migration and repeated hooking, establishing a physically entangled framework reinforced by hydrogen bonds / π-π interactions between the amide backbone and benzene ring side groups. The micropore-channel gradation resulting from the different polarities and stiffness-flexibility of the two fibers enables precise control over thickness and breathability. Subsequently, a hybrid functional sizing agent completes silane hydrolysis-condensation and epoxy ring-opening crosslinking under weakly acidic conditions, forming an organic-inorganic covalent / multi-point hydrogen bond composite film in situ on the fiber surface. This anchors the fiber intersections at multiple scales ("point-line-surface") and improves the interfacial energy, thereby preparing a composite fiber blanket.

[0008] Furthermore, in step S1, the acupuncture parameters are: a needle density of 120-180 needles / cm². 2 The puncture depth is 8-10mm, and the number and direction of needle punctures are two on both sides; In step S2, the post-processing includes: after impregnation, the product is kept at 130-140℃ in a drying zone for 2-4 minutes, followed by spray washing at 40-60℃ until the water conductivity is <50µS / cm. After washing, the product is placed in a vacuum drying oven at 80℃ and vacuum dried to constant weight. Then, the drying oven is heated to 150-160℃ for heat setting for 3-5 minutes to obtain a composite fiber blanket.

[0009] Furthermore, in step S1, the method for preparing the polyphenol-polyamide copolymer fiber includes the following steps: A1. Vanillin, hexamethylenediamine and anhydrous ethanol were added to a reaction vessel and stirred. After nitrogen protection, the pH of the reaction system was adjusted to 5-6 using glacial acetic acid. The temperature of the reaction vessel was then raised to 40-50℃ and kept at that temperature for 4-6 hours. The modified imine was obtained after post-treatment. A2. Add the modified imine and 0.5 mol / L sodium bicarbonate aqueous solution to the reactor, stir under ice-water bath and add 5 wt% sebacate tetrahydrofuran solution, keep warm for interfacial condensation for 1-2 h, and then perform post-treatment to obtain the modified copolymer. A3. Prepare a spinning solution by mixing the modified copolymer, hexafluoroisopropanol and formamide, and obtain the fiber precursor by wet spinning. Transfer the fiber precursor to phosphate buffer, add glutaraldehyde and sodium bisulfite to the system, treat at room temperature for 10-20 min, and then treat to obtain polyphenol-polyamide copolymer fibers.

[0010] The principle for preparing polyphenol-polyamide copolymer fibers is as follows: First, aromatic polyphenol groups are introduced into the chain-forming unit through Schiff base chemistry, enabling the molecule to simultaneously carry active segments capable of forming the amide backbone and side groups with phenolic hydroxyl / aromatic rings. Subsequently, a condensation reaction of acyl chloride-amine groups occurs at the water / organic two-phase interface, rapidly generating a high molecular weight polyamide backbone and fixing the polyphenolic side groups onto the chain in a copolymer form, endowing the system with the self-assembly driving force of π-π stacking and dense hydrogen bond network. Next, in a mild aqueous phase, glutaraldehyde is used to controllably crosslink the phenolic hydroxyl / amine sites, partially regulated and capped by sodium bisulfite, constructing a tunable covalent-non-covalent dual network, improving hydrothermal stability and interfacial adhesion. Finally, through stretching and heat setting to induce chain segment orientation and crystallization perfection, the high-strength backbone of the amide backbone, the multi-point hydrogen bond / π-π physical crosslinking of the aromatic side groups, and the mild chemical crosslinking are synergistically locked, thus obtaining polyphenol-polyamide copolymer fibers.

[0011] Further, in step A1, the ratio of vanillin, hexamethylenediamine, and anhydrous ethanol is 8-10g:5g:80-100mL. The post-treatment includes: after the reaction is completed, wait for the temperature of the reaction system to drop to room temperature, filter the reaction solution to collect the filter cake, wash the filter cake three times with anhydrous ethanol and deionized water, and then transfer the filter cake to a drying oven at 40℃ and vacuum dry it to constant weight to obtain the modified imine. Further, in step A2, the ratio of modified imine, 0.5 mol / L sodium bicarbonate aqueous solution, and 5 wt% sebacate tetrahydrofuran solution is 8-10 g: 200 mL: 120 mL. The post-treatment includes: after the reaction system temperature is raised to room temperature, after the organic phase is separated from the static reaction liquid, 2 times the volume of methanol is added dropwise. After the precipitation is complete, the reaction liquid is filtered to collect the filter cake. The filter cake is washed 3 times with a 1:1 volume ratio of tetrahydrofuran and methanol. The filter cake is then transferred to a drying oven at 40°C and vacuum dried to constant weight to obtain the modified copolymer. Further, in step A3, the ratio of modified copolymer, hexafluoroisopropanol, formamide, phosphate buffer, glutaraldehyde, and sodium bisulfite is 20-24g:180mL:20mL:1000mL:4-5g:2g. The phosphate buffer is prepared by anhydrous sodium dihydrogen phosphate, anhydrous disodium hydrogen phosphate, and deionized water in a ratio of 4.5g:8.5g:1000mL. The post-treatment includes: stretching at a stretch ratio of 3-5 times, washing with water, transferring to a drying oven at 80℃ for vacuum drying to constant weight, and heat-setting at 150℃ for 5 minutes to obtain polyphenol-polyamide copolymer fibers with a length of 50-54mm and a fineness of 2.7-3.0dtex.

[0012] Furthermore, in step S1, the method for preparing the PBS-grafted composite fiber includes the following steps: B1. Add succinic acid, 1,3-propanediol and p-toluenesulfonic acid to the reactor. After purging with nitrogen, raise the temperature of the reactor to 180-200℃ and keep it at this temperature for 4-6 hours. Then, evacuate the reactor and treat it at 3-5 kPa for 1-2 hours under constant temperature and pressure. The post-treatment yields PBS prepolymer. B2. Add PBS prepolymer, styrene, maleic anhydride and benzoyl peroxide to the reactor and stir. Raise the reactor temperature to 180-185℃ and keep it at that temperature for 3-5 minutes. Then lower the reactor temperature to 130-140℃ and evacuate it. Keep it at -0.08MPa for 10-15 minutes. The post-treatment yields the grafted modified resin. B3. Add the grafted modified resin, dichloromethane and dimethylformamide to the reaction vessel and stir. Add the calculated amount of triethanolamine. Raise the temperature of the reaction vessel to 50-60℃ and keep it at this temperature for 2-3 hours to obtain the spinning solution. Obtain the pre-made fiber by electrospinning and then perform post-treatment to obtain PBS grafted composite fiber.

[0013] The principle for preparing PBS-grafted composite fibers is as follows: First, a polypropylene succinate backbone with a certain molecular weight and crystallization potential is obtained by polycondensation of a dicarboxylic acid / diol. Then, under free radical conditions, styrene / maleic anhydride copolymer units are selectively grafted onto the PBS chain, forming a side chain structure containing polar anhydride groups and rigid benzene ring units outside the backbone, which has both interface activation and chain segment reinforcement effects. Next, triethanolamine is used to partially open the ring-opening esterification / amidation of the anhydride sites, converting the active anhydride groups into robust ester / amide-hydroxyl pairs, which significantly improves the hydrogen bonding, polar compatibility and adhesion of the fiber system, while inhibiting the migration of small molecules during subsequent thermal processing. In the forming stage, the chain segment orientation and crystal region are induced by electric field stretching and heat setting, and the physical constraints of the PBS semi-crystalline skeleton and the rigid side groups of styrene are synergistically locked with the polar interaction after ring opening, thus obtaining PBS grafted composite fiber.

[0014] Furthermore, in step B1, the ratio of succinic acid, 1,3-propanediol and p-toluenesulfonic acid is 25g:18-19g:0.1g. The post-processing includes: after the reaction is completed, after the reaction vessel is at room temperature and pressure, the material is taken out and transferred to a drying oven at 80°C for vacuum drying to constant weight to obtain PBS prepolymer. Furthermore, in step B2, the ratio of PBS prepolymer, styrene, maleic anhydride and benzoyl peroxide is 18-20g:1g:0.6g:0.1g. The post-treatment includes: after the reaction is completed, after the reaction vessel is at room temperature and pressure, the material is taken out and transferred to a drying oven at 80°C for vacuum drying to constant weight to obtain grafted modified resin. Furthermore, in step B3, the ratio of grafted modified resin, dichloromethane, and dimethylformamide is 12-15g:100mL:50mL. The amount of triethanolamine added is 0.35-0.40 times that of the anhydride groups in the reaction system. The electrospinning parameters are: voltage 20-25kV, collection distance 15-20cm, and flow rate 0.8-1.0mL / h. The post-treatment includes: transferring the pre-made fiber to a drying oven at 80℃ for vacuum drying to constant weight, and heat-setting at 120℃ for 10min to obtain PBS grafted composite fibers with a length of 50-54mm and a fineness of 2.0-2.4dtex.

[0015] Furthermore, in step S2, the preparation method of the hybrid functional sizing agent includes the following steps: C1. Under nitrogen protection, bisphenol A epoxy resin and acetone were added to the reactor and stirred. 2 wt% sodium alginate aqueous solution was added. After the addition was completed, the pH of the reaction system was adjusted to 9-10 with saturated sodium hydroxide aqueous solution and triethanolamine was added. The temperature of the reactor was raised to 40-50℃ and the reaction was kept at this temperature for 2 hours. The modified epoxy sol was obtained after post-treatment. C2. Add 3-aminopropyltriethoxysilane, nano-silica, anhydrous ethanol and deionized water to the reaction vessel and stir. Adjust the pH of the reaction system to 4-5 using glacial acetic acid and raise the temperature of the reaction vessel to 50-60℃. Keep the temperature and stir for 1-2 hours. Then add the modified epoxy sol and continue stirring for 30-40 minutes. Post-treatment yields the hybrid functional sizing agent.

[0016] The principle for preparing hybrid functional sizing agents is as follows: In an alkaline environment, the hydroxyl / carboxylate salts of sodium alginate undergo nucleophilic ring-opening on bisphenol A epoxy resin, forming an organic sol rich in hydroxyl and amino anchoring sites under the synergistic catalysis and introduction of triethanolamine. This significantly enhances polarity, wetting, and film adhesion. Subsequently, in an acidic ethanol / water medium, 3-aminopropyltriethoxysilane hydrolyzes to produce silanol and condenses with the surface of nano-silica, constructing a continuous Si-O-Si inorganic network. Simultaneously, the -NH2 / -Si-OH groups of silane condense with the hydroxyl groups / residual epoxy in the organic phase or form hydrogen bonds and ion associations, thereby integrating the two phases into a stable organic-inorganic hybrid system through covalent bridging and multi-point hydrogen bonding / van der Waals interactions. After concentration and aging to complete particle size rearrangement and network improvement, a hybrid functional sizing agent is obtained.

[0017] Furthermore, in step C1, the ratio of epoxy resin, acetone, 2wt% sodium alginate aqueous solution and triethanolamine is 8-10g:50mL:100mL:0.3g. The post-treatment includes: after the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, filter the reaction system through a 0.45μm microporous membrane to obtain modified epoxy sol. Further, in step C2, the ratio of 3-aminopropyltriethoxysilane, nano-silica, anhydrous ethanol, deionized water, and modified epoxy sol is 2g:1g:80mL:20mL:8-10g. The post-treatment includes: after stirring, raising the temperature of the reaction vessel to 80℃, concentrating under reduced pressure until the solid content of the reaction system is 8-10wt%, filtering the reaction system through a 0.22μm microporous membrane, and aging in a sealed environment at room temperature for 12h to obtain a hybrid functional sizing agent.

[0018] The present invention has the following beneficial effects: 1. Polyphenol-polyamide copolymer fibers form a stable and fluffy skeleton through orientation and mild cross-linking. The π-π and multi-point hydrogen bonds of the aromatic side groups uniformly lock the micropores, fixing a large amount of static air and significantly reducing the solid heat transfer channels. PBS grafted composite fibers have moderate flexibility and polar anchor points. Under needle punching and traction, they work with the skeleton fibers to create a gradient pore size of "fine pores binding static air - mesopores slow-release convection - interconnected pores diverting flow", reducing air exchange in the thick layer and maintaining resilience, avoiding heat loss caused by pressure collapse. Hybrid functional sizing agents form a thin and tough organic-inorganic bridging membrane at the fiber intersection, achieving point anchoring and line-surface dispersion, weakening the "thermal bridge" between fibers, improving structural density while maintaining porosity, extending the heat flow path and increasing the equivalent thermal resistance as a whole. The combination of these three factors keeps the thickness and microporous structure stable during use, and the static air layer continues to exist, thus achieving higher thermal resistance and longer-lasting heat preservation effect at the same basis weight.

[0019] 2. In the needle punching process of this invention, a connected medium-to-large pore framework is constructed in the thickness direction. The moderate flexibility and resilience of the PBS-grafted fibers stabilize the pore size, reducing channel tortuosity and allowing water vapor to obtain lower path resistance under pressure difference. The fine pores retained by the polyphenol-polyamide fibers only serve as a buffer layer and do not form continuous liquid bridges, avoiding local blockage caused by capillary condensation and structurally reducing the "bottleneck" of water vapor diffusion. At the interface, the hybrid functional sizing agent forms a thin and continuous organic-inorganic bridge with the silane sol-gel through epoxy ring opening. The membrane, with its polar sites such as -OH / -NH on the surface and Si-O-Si network, provides a controllable hydrophilic / hydrophobic balance: on the one hand, it enhances the instantaneous adsorption and desorption rate of water vapor molecules, and on the other hand, it avoids liquid phase retention caused by excessive hydrophilicity, thereby maintaining the effective opening of the gas phase channel. Macroscopically, the pore size distribution presents a gradient of "fine pore buffer - mesopore conduction - macropore pressure relief". Combined with the low tortuosity framework and controlled polar interface, water vapor can pass through the material thickness in a continuous and reversible diffusion-convection recombination manner, significantly reducing the equivalent wet resistance.

[0020] 3. The polyphenol-polyamide copolymer fibers prepared in this invention, after stretching and heat setting, form highly oriented amide backbones and crystalline-amorphous regions that synergistically support each other, providing reversible physical crosslinking for the π-π / multi-point hydrogen bonds of aromatic side groups, thus imparting initial stiffness and energy dissipation capability. The styrene / maleic anhydride side groups of the PBS-grafted composite fibers generate polar anchor points after partial ring opening, improving the interfacial shear strength with the copolymer and compensating for the brittleness of the skeleton with a lower modulus, forming a "strong-tough" combination. Furthermore, the needle-punching process induces three-dimensional entanglement and penetration of the fibers. Through overlapping, the friction-locking effect between fibers is significantly enhanced, suppressing strip tearing and slippage. At the same time, the hybrid functional sizing agent generates a thin and tough organic-inorganic bridging film at the fiber intersection, realizing multi-scale anchoring and load transfer path continuity at points, lines and surfaces, reducing micro-stress concentration and improving the sustained strength under cyclic loading. Overall, the crystal orientation bears the main load, physical / chemical cross-linking and interfacial film layer share and disperse peak stress, and pore gradation reduces notch sensitivity, thereby obtaining higher breaking strength while maintaining the necessary elongation. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In this application, the nano-silica used was purchased from Shanghai McLean Biochemical Technology Co., Ltd., with product number S776198; the bisphenol A type epoxy resin used was purchased from Shandong Qiansheng Chemical Co., Ltd., with brand name E51.

[0023] Example 1 This embodiment provides a method for preparing polyphenol-polyamide copolymer fibers, including the following steps: Step ①: Preparation of modified imine Weigh out 40.0g vanillin, 25.0g hexamethylenediamine and 400.0mL anhydrous ethanol and add them to the reaction vessel. Stir and purge with nitrogen. Adjust the pH of the reaction system to 5 with glacial acetic acid. Then raise the temperature of the reaction vessel to 40℃ and keep it at that temperature for 4 hours. After the reaction is complete, wait for the temperature of the reaction system to drop to room temperature. Filter the reaction liquid and collect the filter cake. Wash the filter cake three times with anhydrous ethanol and deionized water. Transfer the filter cake to a drying oven at 40℃ and vacuum dry it to constant weight to obtain the modified imine.

[0024] Step 2: Preparation of modified copolymer Weigh 40.0 g of modified imine and 1000.0 mL of 0.5 mol / L sodium bicarbonate aqueous solution and add them to the reaction vessel. Stir under an ice-water bath and add 600.0 mL of 5 wt% sebacyl chloride tetrahydrofuran solution. Keep the mixture warm for 1 h for interfacial condensation. After the reaction system temperature rises to room temperature, separate the organic phase from the stagnant reaction liquid and add 2 times the volume of methanol. After the precipitation is complete, filter the reaction liquid and collect the filter cake. Wash the filter cake 3 times with a 1:1 volume ratio of tetrahydrofuran and methanol. Transfer the filter cake to a drying oven at 40 °C and vacuum dry it to constant weight to obtain the modified copolymer.

[0025] Step ③: Preparation of polyphenol-polyamide copolymer fibers Weigh out 4.5g of anhydrous sodium dihydrogen phosphate, 8.5g of anhydrous disodium hydrogen phosphate, and 1000mL of deionized water to prepare a phosphate buffer solution. Weigh out 20.0g of modified copolymer, 180.0mL of hexafluoroisopropanol and 20.0mL of formamide to prepare a spinning solution. Use wet spinning to obtain a fiber precursor. Transfer the fiber precursor to 1000.0mL of phosphate buffer, add 4.0g of glutaraldehyde and 2.0g of sodium bisulfite to the system, treat at room temperature for 10min, stretch at 3 times the draw ratio and wash with water, transfer to a drying oven at 80℃ and vacuum dry to constant weight, and heat set at 150℃ for 5min to obtain polyphenol-polyamide copolymer fibers with a length of 50mm and a fineness of 2.7dtex.

[0026] Example 2 This embodiment provides a method for preparing polyphenol-polyamide copolymer fibers, including the following steps: Step ①: Preparation of modified imine Weigh out 50.0g vanillin, 25.0g hexamethylenediamine and 500.0mL anhydrous ethanol and add them to the reaction vessel. Stir and purge with nitrogen. Adjust the pH of the reaction system to 6 with glacial acetic acid. Then raise the temperature of the reaction vessel to 50℃ and keep it at that temperature for 6 hours. After the reaction is complete, wait for the temperature of the reaction system to drop to room temperature. Filter the reaction liquid and collect the filter cake. Wash the filter cake three times with anhydrous ethanol and deionized water. Transfer the filter cake to a drying oven at 40℃ and dry it under vacuum until constant weight to obtain the modified imine.

[0027] Step 2: Preparation of modified copolymer Weigh 50.0 g of modified imine and 1000.0 mL of 0.5 mol / L sodium bicarbonate aqueous solution and add them to the reaction vessel. Stir under an ice-water bath and add 600.0 mL of 5 wt% sebacyl chloride tetrahydrofuran solution. Keep the mixture warm for 2 h for interfacial condensation. After the reaction system temperature rises to room temperature, separate the organic phase from the stagnant reaction liquid and add 2 times the volume of methanol. After the precipitation is complete, filter the reaction liquid and collect the filter cake. Wash the filter cake 3 times with a 1:1 volume ratio of tetrahydrofuran and methanol. Transfer the filter cake to a drying oven at 40 °C and vacuum dry it to constant weight to obtain the modified copolymer.

[0028] Step ③: Preparation of polyphenol-polyamide copolymer fibers Weigh out 4.5g of anhydrous sodium dihydrogen phosphate, 8.5g of anhydrous disodium hydrogen phosphate, and 1000mL of deionized water to prepare a phosphate buffer solution. Weigh out 24.0 g of modified copolymer, 180.0 mL of hexafluoroisopropanol and 20.0 mL of formamide to prepare a spinning solution. Use wet spinning to obtain a fiber precursor. Transfer the fiber precursor to 1000.0 mL of phosphate buffer, add 5.0 g of glutaraldehyde and 2.0 g of sodium bisulfite to the system, treat at room temperature for 20 min, stretch at a draw ratio of 5, wash with water, transfer to a drying oven at 80 °C and vacuum dry to constant weight, and heat set at 150 °C for 5 min to obtain polyphenol-polyamide copolymer fibers with a length of 54 mm and a fineness of 3.0 dtex.

[0029] Example 3 This embodiment provides a method for preparing polyphenol-polyamide copolymer fibers, including the following steps: Step ①: Preparation of modified imine Weigh out 45.0g vanillin, 25.0g hexamethylenediamine and 450.0mL anhydrous ethanol and add them to the reaction vessel. Stir and purge with nitrogen. Adjust the pH of the reaction system to 5 with glacial acetic acid. Then raise the temperature of the reaction vessel to 45℃ and keep it at that temperature for 5 hours. After the reaction is complete, wait for the temperature of the reaction system to drop to room temperature. Filter the reaction liquid and collect the filter cake. Wash the filter cake three times with anhydrous ethanol and deionized water. Transfer the filter cake to a drying oven at 40℃ and dry it under vacuum until constant weight to obtain the modified imine.

[0030] Step 2: Preparation of modified copolymer Weigh 45.0 g of modified imine and 1000.0 mL of 0.5 mol / L sodium bicarbonate aqueous solution and add them to the reaction vessel. Stir under an ice-water bath and add 600.0 mL of 5 wt% sebacyl chloride tetrahydrofuran solution. Keep the mixture warm for 2 h for interfacial condensation. After the reaction system temperature rises to room temperature, separate the organic phase from the stagnant reaction liquid and add 2 times the volume of methanol. After the precipitation is complete, filter the reaction liquid and collect the filter cake. Wash the filter cake 3 times with a 1:1 volume ratio of tetrahydrofuran and methanol. Transfer the filter cake to a drying oven at 40 °C and vacuum dry it to constant weight to obtain the modified copolymer.

[0031] Step ③: Preparation of polyphenol-polyamide copolymer fibers Weigh out 4.5g of anhydrous sodium dihydrogen phosphate, 8.5g of anhydrous disodium hydrogen phosphate, and 1000mL of deionized water to prepare a phosphate buffer solution. Weigh out 21.0 g of modified copolymer, 180.0 mL of hexafluoroisopropanol and 20.0 mL of formamide to prepare a spinning solution. Use wet spinning to obtain a fiber precursor. Transfer the fiber precursor to 1000.0 mL of phosphate buffer, add 4.5 g of glutaraldehyde and 2.0 g of sodium bisulfite to the system, treat at room temperature for 15 min, stretch at a draw ratio of 4, wash with water, transfer to a drying oven at 80 °C and vacuum dry to constant weight, and heat set at 150 °C for 5 min to obtain polyphenol-polyamide copolymer fibers with a length of 51 mm and a fineness of 2.8 dtex.

[0032] Example 4 This embodiment provides a method for preparing PBS-grafted composite fibers, including the following steps: Step (1): Preparation of PBS prepolymer Weigh out 25.0g of succinic acid, 18.0g of 1,3-propanediol and 0.1g of p-toluenesulfonic acid and add them to the reactor. After purging with nitrogen, the reactor temperature is raised to 180℃ and kept at this temperature for 4 hours. Then, vacuum is applied and the reactor is kept at 3kPa and constant temperature and pressure for 1 hour. After the reaction is complete, the reactor is allowed to return to normal temperature and pressure. The material is then removed and transferred to a drying oven at 80℃ and vacuum dried to constant weight to obtain PBS prepolymer.

[0033] Step 2: Preparation of graft-modified resin Weigh out 18.0g of PBS prepolymer, 1.0g of styrene, 0.6g of maleic anhydride and 0.1g of benzoyl peroxide and add them to the reactor. Stir the reactor and raise the temperature to 180℃. After holding the temperature for 3 minutes, lower the temperature to 130℃ and apply a vacuum. Treat the reactor at -0.08MPa for 10 minutes. After the reaction is complete, wait for the reactor to return to normal temperature and pressure, then remove the material and transfer it to a drying oven at 80℃. Vacuum dry the material to constant weight to obtain the grafted modified resin.

[0034] Step 3: Preparation of PBS-grafted composite fibers Weigh out 12.0 g of grafted modified resin, 100.0 mL of dichloromethane and 50.0 mL of dimethylformamide and add them to the reaction vessel. Stir the mixture and add triethanolamine in an amount equal to 0.35 times the amount of anhydride groups in the reaction system. Raise the temperature of the reaction vessel to 50 °C and keep it at that temperature for 2 h to obtain the spinning solution. Control the spinning voltage at 20 kV, the collection distance at 15 cm, and the flow rate at 0.8 mL / h. Obtain the pre-made fiber by electrospinning. Transfer the pre-made fiber to a drying oven at 80 °C and vacuum dry it to constant weight. Heat set it at 120 °C for 10 min to obtain PBS grafted composite fiber with a length of 50 mm and a fineness of 2.0 dtex.

[0035] Example 5 This embodiment provides a method for preparing PBS-grafted composite fibers, including the following steps: Step (1): Preparation of PBS prepolymer Weigh out 25.0g of succinic acid, 19.0g of 1,3-propanediol and 0.1g of p-toluenesulfonic acid and add them to the reactor. After purging with nitrogen, the temperature of the reactor is raised to 200℃ and kept at this temperature for 6 hours. Then, vacuum is applied and the reactor is treated at 5kPa for 2 hours under constant temperature and pressure. After the reaction is completed, the reactor is allowed to return to normal temperature and pressure. The material is then removed and transferred to a drying oven at 80℃ and vacuum dried to constant weight to obtain PBS prepolymer.

[0036] Step 2: Preparation of graft-modified resin Weigh out 20.0g of PBS prepolymer, 1.0g of styrene, 0.6g of maleic anhydride and 0.1g of benzoyl peroxide and add them to the reactor. Stir the reactor and raise the temperature to 185℃. After holding the temperature for 5 minutes, lower the temperature to 140℃ and apply a vacuum. Treat the reactor at -0.08MPa for 15 minutes. After the reaction is complete, wait for the reactor to return to normal temperature and pressure, then remove the material and transfer it to a drying oven at 80℃. Vacuum dry the material to constant weight to obtain the grafted modified resin.

[0037] Step 3: Preparation of PBS-grafted composite fibers Weigh out 15.0g of grafted modified resin, 100.0mL of dichloromethane and 50.0mL of dimethylformamide and add them to the reaction vessel. Stir the mixture and add triethanolamine in an amount equal to 0.40 times the amount of anhydride groups in the reaction system. Raise the temperature of the reaction vessel to 60℃ and keep it at that temperature for 3 hours to obtain the spinning solution. Control the spinning voltage at 25kV, the collection distance at 20cm and the flow rate at 1.0mL / h. Obtain the pre-made fiber by electrospinning. Transfer the pre-made fiber to a drying oven at 80℃ and vacuum dry it to constant weight. Heat set it at 120℃ for 10 minutes to obtain PBS grafted composite fiber with a length of 54mm and a fineness of 2.4dtex.

[0038] Example 6 This embodiment provides a method for preparing PBS-grafted composite fibers, including the following steps: Step (1): Preparation of PBS prepolymer Weigh out 25.0g of succinic acid, 18.5g of 1,3-propanediol and 0.1g of p-toluenesulfonic acid and add them to the reactor. After purging with nitrogen, the temperature of the reactor is raised to 190℃ and kept at this temperature for 5 hours. Then, vacuum is applied and the reactor is kept at 4kPa and constant temperature and pressure for 2 hours. After the reaction is complete, the reactor is allowed to return to normal temperature and pressure. The material is then removed and transferred to a drying oven at 80℃ and vacuum dried to constant weight to obtain PBS prepolymer.

[0039] Step 2: Preparation of graft-modified resin Weigh out 20.0g of PBS prepolymer, 1.0g of styrene, 0.6g of maleic anhydride and 0.1g of benzoyl peroxide and add them to the reactor. Stir the reactor and raise the temperature to 184℃. After holding the temperature for 4 minutes, lower the temperature to 140℃ and apply a vacuum. Treat the reactor at -0.08MPa for 15 minutes. After the reaction is complete, wait for the reactor to return to normal temperature and pressure, then remove the material and transfer it to a drying oven at 80℃. Vacuum dry the material to constant weight to obtain the grafted modified resin.

[0040] Step 3: Preparation of PBS-grafted composite fibers Weigh out 13.5g of grafted modified resin, 100.0mL of dichloromethane and 50.0mL of dimethylformamide and add them to the reaction vessel. Stir the mixture and add triethanolamine in an amount equal to 0.36 times the amount of anhydride groups in the reaction system. Raise the temperature of the reaction vessel to 55℃ and keep it at that temperature for 3 hours to obtain the spinning solution. Control the spinning voltage to 24kV, the collection distance to 18cm, and the flow rate to 0.9mL / h. Obtain the pre-made fiber by electrospinning. Transfer the pre-made fiber to a drying oven at 80℃ and vacuum dry it to constant weight. Heat set it at 120℃ for 10 minutes to obtain PBS grafted composite fiber with a length of 51mm and a fineness of 2.1dtex.

[0041] Example 7 This embodiment provides a method for preparing a hybrid functional sizing agent, including the following steps: Step I: Preparation of modified epoxy sol Under nitrogen protection, 16.0 g of bisphenol A epoxy resin and 100.0 mL of acetone were weighed and added to the reaction vessel and stirred. Then, 200.0 mL of 2 wt% sodium alginate aqueous solution was added. After the addition was complete, the pH of the reaction system was adjusted to 9 using saturated sodium hydroxide aqueous solution and 0.6 g of triethanolamine was added. The temperature of the reaction vessel was raised to 40 °C and the reaction was maintained for 2 h. The modified epoxy sol was obtained after post-treatment.

[0042] Step II: Preparation of hybrid functional sizing agent Weigh out 2.0g of 3-aminopropyltriethoxysilane, 1.0g of nano-silica, 80.0mL of anhydrous ethanol and 20.0mL of deionized water and add them to the reaction vessel and stir. Adjust the pH of the reaction system to 4 using glacial acetic acid and raise the temperature of the reaction vessel to 50℃. Keep the temperature and stir for 1h. Then add 8.0g of modified epoxy sol and continue stirring for 30min. Post-treatment yields a hybrid functional sizing agent.

[0043] Example 8 This embodiment provides a method for preparing a hybrid functional sizing agent, including the following steps: Step I: Preparation of modified epoxy sol Under nitrogen protection, 20.0g of bisphenol A epoxy resin and 100.0mL of acetone were weighed and added to the reaction vessel and stirred. Then, 200.0mL of 2wt% sodium alginate aqueous solution was added. After the addition was complete, the pH of the reaction system was adjusted to 10 using saturated sodium hydroxide aqueous solution and 0.3g of triethanolamine was added. The temperature of the reaction vessel was raised to 50℃ and the reaction was maintained for 2 hours. The modified epoxy sol was obtained after post-treatment.

[0044] Step II: Preparation of hybrid functional sizing agent Weigh out 2.0g of 3-aminopropyltriethoxysilane, 1.0g of nano-silica, 80.0mL of anhydrous ethanol and 20.0mL of deionized water and add them to the reaction vessel and stir. Adjust the pH of the reaction system to 5 with glacial acetic acid and raise the temperature of the reaction vessel to 60℃. Keep the temperature and stir for 2h. Then add 10.0g of modified epoxy sol and continue stirring for 40min. Post-treatment yields a hybrid functional sizing agent.

[0045] Example 9 This embodiment provides a method for preparing a hybrid functional sizing agent, including the following steps: Step I: Preparation of modified epoxy sol Under nitrogen protection, 18.0 g of bisphenol A epoxy resin and 100.0 mL of acetone were weighed and added to the reaction vessel and stirred. Then, 200.0 mL of 2 wt% sodium alginate aqueous solution was added. After the addition was complete, the pH of the reaction system was adjusted to 10 using saturated sodium hydroxide aqueous solution and 0.6 g of triethanolamine was added. The temperature of the reaction vessel was raised to 45°C and the reaction was maintained for 2 hours. The modified epoxy sol was obtained after post-treatment.

[0046] Step II: Preparation of hybrid functional sizing agent Weigh out 2.0g of 3-aminopropyltriethoxysilane, 1.0g of nano-silica, 80.0mL of anhydrous ethanol and 20.0mL of deionized water and add them to the reaction vessel and stir. Adjust the pH of the reaction system to 5 using glacial acetic acid and raise the temperature of the reaction vessel to 54℃. Keep the temperature and stir for 2h. Then add 9.0g of modified epoxy sol and continue stirring for 35min. Post-treatment yields a hybrid functional sizing agent.

[0047] Example 10 This embodiment provides a method for preparing a composite fiber blanket, including the following steps: Step 1: Preparing the pre-cured blanket Weigh out 6 parts by weight of the polyphenol-polyamide copolymer fiber prepared in Example 1 and 4 parts by weight of the PBS grafted composite fiber prepared in Example 4, open and mix them, humidify at 20°C and 55%RH for 4 hours, and then card and cross-lay the fiber to a density of 300 g / m². 2 A fiber web is formed, and then the needle density is 120 needles / cm. 2 A pre-fixed blanket was obtained by needling with parameters of 8mm puncture depth and 2 needle passes on both sides.

[0048] Step 2: Preparation of composite fiber blankets Weighing: By volume, weigh 20 parts of the hybrid functional sizing agent prepared in Example 7, 4 parts of anhydrous ethanol and 1 part of deionized water and add them to the reaction vessel and stir. After adjusting the pH of the system to 5.0 with glacial acetic acid, a sizing solution is obtained. The sizing solution is used to perform two dips and two nips on the pre-cured blanket, controlling the nips ratio to 60%. After dipping, the blanket is kept at 130℃ for 2 minutes in the drying zone, and then sprayed with water at 40℃ until the water conductivity is <50µS / cm. After washing, the product is placed in a vacuum drying oven at 80℃ and vacuum dried to constant weight. Then the drying oven is heated to 150℃ for heat setting for 3 minutes to obtain the composite fiber blanket.

[0049] Example 11 This embodiment provides a method for preparing a composite fiber blanket, including the following steps: Step 1: Preparing the pre-cured blanket Weigh out 6 parts by weight of the polyphenol-polyamide copolymer fiber prepared in Example 2 and 5 parts by weight of the PBS grafted composite fiber prepared in Example 5, open and mix them, humidify at 24°C and 65%RH for 6 hours, and then card and cross-lay the fiber to a density of 300 g / m². 2 A fiber web is formed, and then the needle density is 180 needles / cm. 2 A pre-fixed blanket was obtained by needling with parameters of 10mm puncture depth and 2 needle passes on both sides.

[0050] Step 2: Preparation of composite fiber blankets Weighing: By volume, weigh 20 parts of the hybrid functional sizing agent prepared in Example 8, 4 parts of anhydrous ethanol and 1 part of deionized water and add them to the reaction vessel and stir. After adjusting the pH of the system to 5.0 with glacial acetic acid, a sizing solution is obtained. The sizing solution is used to perform two dips and two nips on the pre-cured blanket, controlling the nips ratio to 80%. After dipping, the blanket is kept at 140℃ for 4 minutes in the drying zone, and then sprayed with water at 60℃ until the water conductivity is <50µS / cm. After washing, the product is placed in a vacuum drying oven at 80℃ and vacuum dried to constant weight. Then the drying oven is heated to 160℃ for heat setting for 5 minutes to obtain the composite fiber blanket.

[0051] Example 12 This embodiment provides a method for preparing a composite fiber blanket, including the following steps: Step 1: Preparing the pre-cured blanket Weigh out 6 parts by weight of the polyphenol-polyamide copolymer fiber prepared in Example 3 and 5 parts by weight of the PBS grafted composite fiber prepared in Example 6, open and mix them, humidify at 21°C and 60%RH for 5 hours, and then card and cross-lay the fiber to a density of 300 g / m². 2 A fiber web is formed, and then the needle density is 160 needles / cm. 2 A pre-fixed blanket was obtained by needling with parameters of 9mm puncture depth and 2 needle passes on both sides.

[0052] Step 2: Preparation of composite fiber blankets Weighing: By volume, weigh 20 parts of the hybrid functional sizing agent prepared in Example 9, 4 parts of anhydrous ethanol and 1 part of deionized water and add them to the reaction vessel and stir. After adjusting the pH of the system to 5.0 with glacial acetic acid, a sizing solution is obtained. The sizing solution is used to perform two dips and two nips on the pre-cured blanket, controlling the nips ratio to 70%. After dipping, the blanket is kept at 135℃ for 3 minutes in the drying zone, and then sprayed with water at 50℃ until the water conductivity is <50µS / cm. After washing, the product is placed in a vacuum drying oven at 80℃ and vacuum dried to constant weight. Then the drying oven is heated to 155℃ for heat setting for 4 minutes to obtain the composite fiber blanket.

[0053] Comparative Example 1 The difference between this comparative example and Example 12 is that, in step ③ of the preparation of the polyphenol-polyamide copolymer fiber, the addition of glutaraldehyde and sodium bisulfite was omitted.

[0054] Comparative Example 2 The difference between this comparative example and Example 12 is that the addition of triethanolamine was omitted in step (3) of the preparation of the PBS-grafted composite fiber.

[0055] Comparative Example 3 The difference between this comparative example and Example 12 is that the hybrid functional sizing agent used in step II of preparation omits the use of 3-aminopropyltriethoxysilane and nano-silica.

[0056] Performance testing: The tensile strength and elongation at break of the composite fiber blankets prepared in Examples 10-12 and Comparative Examples 1-3 were determined in accordance with the standard GB / T 24218.18-2014 "Textiles - Nonwovens - Test Methods - Part 18: Determination of breaking strength and elongation at break (sampling method)". The moisture resistance and thermal resistance of the composite fiber blankets prepared in Examples 10-12 and Comparative Examples 1-3 were measured in accordance with the standard GB / T 11048-2018 "Determination of thermal resistance and moisture resistance of textiles under steady-state conditions for physiological comfort (evaporative hot plate method)". The specific data are shown in Table 1. Table 1 - Performance Test Data for Each Sample

[0057] Data Analysis: Comparative analysis of the data in Table 1 reveals that the composite fiber blanket prepared by this invention has a warp breaking strength of 238 N, a weft breaking strength of 180 N, a warp breaking elongation of 39%, a weft breaking elongation of 45%, and a thermal resistance of 0.165 m. 2 ·K·W -1 Meanwhile, the moisture resistance is 22.7m. 2 ·Pa·W -1 All data points are better than the comparative data, indicating that: After losing the micro-scale anchors of glutaraldehyde / sodium bisulfite in Comparative Example 1, the shear bearing capacity at the fiber intersection decreased, the entanglement loosened under load and damp heat shock, the pore wall was more likely to collapse and form thermal bridges, resulting in a shortened heat flow path, enhanced micro-convection, and difficulty in locking the orientation. Comparative Example 2 shows that the loss of triethanolamine ring-opening keeps the anhydride group highly reactive and low polar, reduces compatibility and interfacial energy, and induces defect nuclei through local phase separation; load transfer shows a "slip-discontinuous" chain, the tortuosity of the pores increases, water vapor diffusion is hindered, and stress concentration triggers premature failure. After losing the silane / silica bridging in Comparative Example 3, the slurry film changed from "point and line anchoring" to partial surface coverage, resulting in poor interface continuity and creep resistance, easy blockage of orifices and uneven film thickness. As a result, the effective opening rate of the channel decreased, thermal bridge reduction was insufficient, stress distribution was uneven, and the overall performance deteriorated simultaneously. In conclusion, this invention constructs a continuous pathway for water vapor migration. Polyphenol-polyamide copolymer fibers, through orientation and mild cross-linking, stabilize their thick-section deformation, while micropores maintain a "buffer layer," preventing water vapor condensation and retention within the pores. PBS-grafted composite fibers, after anhydride ring-opening, acquire appropriate polarity and resilience, shaping a mesoporous-macroporous framework under needle-punching traction, reducing channel tortuosity and maintaining an open state. A hybrid functional sizing agent, through epoxy ring-opening and silane sol-gel, generates a thin organic-inorganic bridging membrane at fiber intersections. The surface -OH / -NH and Si-O-Si networks provide a rapid adsorption-desorption interface, increasing the water vapor diffusion rate without clogging pores. These three elements are continuously connected through site reactions, chain segment structures, and forming processes, significantly reducing moisture resistance under steady-state conditions, while also exhibiting excellent thermal insulation and mechanical properties.

[0058] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

[0059] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0060] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a composite fiber blanket, characterized in that, Includes the following steps: S1. Weigh out 6 parts of polyphenol-polyamide copolymer fiber and 4-5 parts of PBS grafted composite fiber by weight, open and mix them, humidify them at 20-24℃ and 55-65%RH for 4-6 hours, comb and cross-lay the fiber web to the target weight to form a fiber web, and then needle punch to obtain a pre-cured blanket. S2. Weigh out 20 parts by volume of hybrid functional sizing agent, 4 parts by volume of anhydrous ethanol and 1 part by volume of deionized water and add them to the reaction vessel and stir. Adjust the pH of the system to 5.0 with glacial acetic acid to obtain sizing solution. Use the sizing solution to perform two dips and two nips on the pre-cured blanket, controlling the nips ratio to 60-80%. The post-treatment yields the composite fiber blanket.

2. The method for preparing a composite fiber blanket according to claim 1, characterized in that, In step S1, the acupuncture parameters are: needle density of 120-180 needles / cm². 2 The puncture depth is 8-10mm, and the number of needle passes and the direction of the needle passes are two on both sides.

3. The method for preparing a composite fiber blanket according to claim 1, characterized in that, In step S1, the method for preparing the polyphenol-polyamide copolymer fiber includes the following steps: A1. Vanillin, hexamethylenediamine and anhydrous ethanol were added to a reaction vessel and stirred. After nitrogen protection, the pH of the reaction system was adjusted to 5-6 using glacial acetic acid. The temperature of the reaction vessel was then raised to 40-50℃ and kept at that temperature for 4-6 hours. The modified imine was obtained after post-treatment. A2. Add the modified imine and 0.5 mol / L sodium bicarbonate aqueous solution to the reactor, stir under ice-water bath and add 5 wt% sebacate tetrahydrofuran solution, keep warm for interfacial condensation for 1-2 h, and then perform post-treatment to obtain the modified copolymer. A3. Prepare a spinning solution by mixing the modified copolymer, hexafluoroisopropanol and formamide, and obtain the fiber precursor by wet spinning. Transfer the fiber precursor to phosphate buffer, add glutaraldehyde and sodium bisulfite to the system, treat at room temperature for 10-20 min, and then treat to obtain polyphenol-polyamide copolymer fibers.

4. The method for preparing a composite fiber blanket according to claim 3, characterized in that, In step A1, the ratio of vanillin, hexamethylenediamine, and anhydrous ethanol is 8-10g:5g:80-100mL; in step A2, the ratio of modified imine, 0.5mol / L sodium bicarbonate aqueous solution, and 5wt% sebacate tetrahydrofuran solution is 8-10g:200mL:120mL.

5. The method for preparing a composite fiber blanket according to claim 3, characterized in that, In step A3, the ratio of the modified copolymer, hexafluoroisopropanol, formamide, phosphate buffer, glutaraldehyde, and sodium bisulfite is 20-24g:180mL:20mL:1000mL:4-5g:2g. The phosphate buffer is prepared by anhydrous sodium dihydrogen phosphate, anhydrous disodium hydrogen phosphate, and deionized water in a ratio of 4.5g:8.5g:1000mL.

6. The method for preparing a composite fiber blanket according to claim 1, characterized in that, In step S1, the method for preparing the PBS-grafted composite fiber includes the following steps: B1. Add succinic acid, 1,3-propanediol and p-toluenesulfonic acid to the reactor. After purging with nitrogen, raise the temperature of the reactor to 180-200℃ and keep it at this temperature for 4-6 hours. Then, evacuate the reactor and treat it at 3-5 kPa for 1-2 hours under constant temperature and pressure. The post-treatment yields PBS prepolymer. B2. Add PBS prepolymer, styrene, maleic anhydride and benzoyl peroxide to the reactor and stir. Raise the reactor temperature to 180-185℃ and keep it at that temperature for 3-5 minutes. Then lower the reactor temperature to 130-140℃ and evacuate it. Keep it at -0.08MPa for 10-15 minutes. The post-treatment yields the grafted modified resin. B3. Add the grafted modified resin, dichloromethane and dimethylformamide to the reaction vessel and stir. Add the calculated amount of triethanolamine. Raise the temperature of the reaction vessel to 50-60℃ and keep it at that temperature for 2-3 hours to obtain the spinning solution. Obtain the pre-made fiber by electrospinning and then undergo post-treatment to obtain the grafted composite fiber.

7. The method for preparing a composite fiber blanket according to claim 6, characterized in that, In step B1, the ratio of succinic acid, 1,3-propanediol and p-toluenesulfonic acid is 25g:18-19g:0.1g; in step B2, the ratio of PBS prepolymer, styrene, maleic anhydride and benzoyl peroxide is 18-20g:1g:0.6g:0.1g.

8. The method for preparing a composite fiber blanket according to claim 6, characterized in that, In step B3, the ratio of grafted modified resin, dichloromethane, and dimethylformamide is 12-15g:100mL:50mL. The amount of triethanolamine added is 0.35-0.40 times that of the anhydride groups in the reaction system. The electrospinning parameters are: voltage 20-25kV, collection distance 15-20cm, and flow rate 0.8-1.0mL / h.

9. The method for preparing a composite fiber blanket according to claim 1, characterized in that, In step S2, the preparation method of the hybrid functional sizing agent includes the following steps: C1. Under nitrogen protection, bisphenol A epoxy resin and acetone were added to the reactor and stirred. 2 wt% sodium alginate aqueous solution was added. After the addition was completed, the pH of the reaction system was adjusted to 9-10 with saturated sodium hydroxide aqueous solution and triethanolamine was added. The temperature of the reactor was raised to 40-50℃ and the reaction was kept at this temperature for 2 hours. The modified epoxy sol was obtained after post-treatment. C2. Add 3-aminopropyltriethoxysilane, nano-silica, anhydrous ethanol and deionized water to the reaction vessel and stir. Adjust the pH of the reaction system to 4-5 using glacial acetic acid and raise the temperature of the reaction vessel to 50-60℃. Keep the temperature and stir for 1-2 hours. Then add the modified epoxy sol and continue stirring for 30-40 minutes. Post-treatment yields the hybrid functional sizing agent.

10. The method for preparing a composite fiber blanket according to claim 9, characterized in that, In step C1, the ratio of epoxy resin, acetone, 2wt% sodium alginate aqueous solution and triethanolamine is 8-10g:50mL:100mL:0.3g; in step C2, the ratio of 3-aminopropyltriethoxysilane, nano silica, anhydrous ethanol, deionized water and modified epoxy sol is 2g:1g:80mL:20mL:8-10g.

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