Superfine fiber regenerated material with charged gradient structure and preparation method thereof

Abstract

The invention provides a superfine fiber regenerated material with a charged gradient structure and a preparation method of the superfine fiber regenerated material, and relates to the technical field of non-woven fabric preparation. The preparation method of the superfine fiber regenerated material comprises the following steps: S1, preparing a cellulose stock solution; s2, forming the cellulose melt-blown non-woven fabric; and S3, recycling the NMMO solvent. The NMMO solution and other organic compound impurities which are not completely reacted can be separated through rectification and purification, and the purity of the NMMO is accurately improved, so that the NMMO reaches a higher quality standard; degradation products such as residual chains can be removed in a targeted manner through micellar enhanced ultrafiltration, so that the quality of NMMO is more stable; impurities such as residual chains, bacteria and metal ions are removed and degraded through rectification and purification, the chemical stability of the NMMO solution is enhanced, and the NMMO solution has better dissolving capacity and chemical stability.

Description

Technical Field

[0001] The invention relates to the technical field of nonwoven fabric preparation, in particular to an ultrafine fiber recycled material with an electric gradient structure and a preparation method thereof. Background Art

[0002] Cellulose is the most abundant biosolubilizable and biodegradable resource in nature. It is one of the main components of plant cell walls and accounts for more than 50% of the carbon content in the plant kingdom. Nonwoven fabrics made of cellulose have broad application prospects in the fields of textiles, filter materials, special papers, sanitary products, etc. due to their good wearing properties, mechanical properties, biodegradability, etc. Regenerated cellulose fibers made from wood pulp (cellulose) play an important role in textile and technical applications. Therefore, the development of degradable melt-blown nonwoven materials has become a research hotspot in academia and industry in recent years, and new degradable melt-blown fabric products have also received widespread attention from all walks of life. There is a prior art method for manufacturing cellulose nonwoven fabrics, which uses amine oxide as a solvent to dissolve cellulose and improves the traditional melt-blown process to prepare cellulose nonwoven fabrics. However, the tertiary amine oxide solvent used in this method is expensive, and the synthesis technology is monopolized by foreign countries. At the same time, the solvent is unstable at room temperature and easily decomposes at high temperatures, posing serious safety hazards. In addition, the fiber web receiving device in the prior art is a roller with a dry surface or a non-solvent, which is prone to the problem of filaments sticking to each other, affecting the performance and application of the nonwoven fabric.

[0003] Degradable nonwoven fabrics have always been a hot topic in recent years. How to prepare cellulose melt-blown fabrics cost-effectively and smoothly is an urgent issue. In the existing cellulose melt-blown fabric process, the improvement of fiber drafting and receiving devices is the focus of the present invention. On the basis of the traditional melt-blown process, it is of great theoretical value and practical significance to explore the cellulose melt-blown forming mechanism and form a stable, continuous and efficient cellulose melt-blown nonwoven material forming process technology scheme. At the same time, in the process of recycling NMMO solvent, some by-products may be produced, such as degraded NMMO or other organic compounds. In order to avoid pollution to the environment, these by-products need to be thoroughly treated and purified. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides an ultrafine fiber recycled material with an electrical gradient structure and a preparation method thereof, which solves the problem that the traditional process flow cannot ensure the continuity and uniformity of cellulose filaments and the structural performance requirements of different terminal applications, and the recovery of NMMO solvent will cause pollution to the environment.

[0005] To achieve the above objectives, the present invention is implemented through the following technical scheme: a superfine fiber recycled material with an electric gradient structure, comprising the following percentages of raw materials: 86% to 96% cellulose pulp, 1% to 5% alumina nanopowder, 2% to 5% plasticizer, 0.1% to 1% surfactant, 0.1% to 0.5% antioxidant, and 0.8% to 2.5% nano silicon dioxide.

[0006] The method for preparing a superfine fiber recycled material with an electric gradient structure comprises the following steps:

[0007] S1. Preparation of cellulose stock solution

[0008] The NMMO solution with a concentration of 50% is concentrated under vacuum, and then mixed with cellulose pulp under vacuum and heating conditions to dissolve, and aluminum oxide nanopowder, plasticizer, surfactant, antioxidant and nano-silicon dioxide are added to the stock solution to obtain a clarified cellulose spinning stock solution;

[0009] S2. Forming of cellulose melt-blown nonwoven fabrics

[0010] The cellulose stock solution obtained above is poured into a dissolving kettle, and nitrogen is introduced, and extruded through the spinneret holes of the spinneret die head, and the ejected cellulose filaments are stretched and refined by high-speed airflow, and the cellulose filaments are cooled and pre-solidified by water mist at the same time, and a fiber web with a gradient structure is obtained by controlling the stretching distance and spraying distance of the front and rear spinnerets, and then the pre-solidified cellulose filaments are self-bonded on the receiving mesh curtain to form a fiber web, and the obtained fiber web is immersed in a coagulation bath to precipitate the solvent, and finally washed, dried, and wound to obtain a cellulose melt-blown cloth;

[0011] S3. Recycling of NMMO solvent

[0012] The coagulation bath after the cellulose filaments are coagulated and the liquid after washing are collected in the above step, and after being treated, the NMMO solvent in the solution is recovered by vacuum distillation.

[0013] Preferably, in step S1, the concentration of the NMMO solvent after concentration is not less than 80wt%; the NMMO solution is preheated after concentration, and the preheating temperature is the dissolution temperature of cellulose in the solution; the mixing stirring rate of the NMMO solvent and the cellulose pulp is 150-400rpm; the average degree of polymerization of the cellulose pulp is 400-600bp; and the concentration of the cellulose spinning solution is 3-10wt%.

[0014] Preferably, in step S2, the temperature of the spinneret is 90-110°C, and the diameter of the spinneret hole is 0.3-0.4 mm; the speed of the high-speed airflow is 10-30 m / s; the water used for spraying is tap water; at least two spinnerets are provided, and the receiving mesh curtain is sprayed in turn by multiple spinnerets to obtain a fiber web with a gradient structure, the spray height sprayed by the spray nozzle is the spray distance, the spray distance can be adjusted within the range of 15-35 cm, the distance between the spinneret and the receiving mesh curtain is the drawing distance, and the drawing distance can be adjusted within the range of 20-50 cm.

[0015] Preferably, in step S2, the specific process of cooling and pre-solidifying the cellulose filaments by spraying is as follows:

[0016] Turn on the tap water spray system and maintain the spray pressure at 0.05-0.2MPa.

[0017] Preferably, step S3 specifically includes the following process:

[0018] S31. First, the liquid is coarsely filtered using a filter to remove large solid impurities; then a hydrophilic polymer membrane is used for microfiltration to further remove small solid impurities, bacteria and macromolecular colloids;

[0019] S32. Sodium dodecyl sulfate was selected as the surfactant micelle, and NMMO was treated by micelle-enhanced ultrafiltration to remove the degraded residual chains and adsorb metal ions;

[0020] S33. The purified NMMO solution is concentrated by a vacuum distillation process, and the concentrated NMMO solution is purified by distillation to further remove impurities therein and improve the purity of NMMO.

[0021] The application of ultrafine fiber regenerated materials in facial mask base fabrics, mask substrates, sanitary products, and filter materials, wherein the average fiber diameter of the ultrafine fiber regenerated materials is 0.8 to 5.0 μm, and the charge is 0.5 to 1.5 Kv. When the ultrafine fiber regenerated materials are applied to the facial mask base fabric and applied for 20 minutes, the skin's absorption of essence is increased by 10 to 20%.

[0022] The present invention provides an ultrafine fiber recycled material with an electric gradient structure and a preparation method thereof.

[0023] Beneficial effects:

[0024] 1. The present invention can increase the plasticity of cellulose by adding plasticizers, making it easier to flow and deform during processing, thereby helping to spray out uniform cellulose filaments. Surfactants can reduce the surface tension of the solution, making it easier for the cellulose solution to spray out from the spinneret hole, and can improve the surface properties of the cellulose filaments, making them smoother and more uniform. Antioxidants can prevent cellulose from oxidative degradation under conditions such as high temperature and light, and maintain the stability of cellulose; for example, adding natural antioxidants such as vitamin E, vitamin C, anthocyanins, etc., when used for mask base fabrics, also has the effect of improving skin care effects. Nano-silicon dioxide has a high specific surface area and good dispersibility, and can form hydrogen bonds and physical adsorption with cellulose molecules to improve the strength and stability of cellulose filaments. In addition, alumina nanopowders with a high dielectric constant are incorporated therein, and the nanoparticles can be used as charge capture points, which not only improves the ability to capture friction charges on the surface of the material, but also increases the ability of the material to retain friction charges, thereby increasing the surface charge density of the material.

[0025] 2. The present invention uses a filter screen for coarse filtration, which can effectively intercept larger solid particles in the liquid, prevent these large particles from entering the subsequent fine processing link, and avoid blockage and wear damage to the equipment; the hydrophilic polymer membrane microfiltration treatment further purifies on this basis, which helps to improve the purity and stability of the liquid; NMMO may degrade during use or storage, producing some residual chains. The presence of these residual chains will affect the performance of NMMO. These degradation products can be removed specifically by micelle-enhanced ultrafiltration, making the quality of NMMO more stable; the vacuum distillation process can remove low-boiling impurities in the solution, such as residual organic solvents, water, etc.; distillation purification can separate the unreacted NMMO solution and other organic compound impurities, accurately improve the purity of NMMO, and make it reach higher quality standards; by removing impurities such as degradation residual chains, bacteria, metal ions, etc., the chemical stability of the NMMO solution is enhanced, and it has better solubility and chemical stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The SEM images of the cellulose melt-blown fabrics prepared in the comparative example and the first embodiment of the present invention, a is the cellulose melt-blown fabric prepared in the comparative example without the spray system, and b is the cellulose melt-blown fabric prepared in the first embodiment with the spray system;

[0027] Figure 2 It is a schematic diagram of the molding process of the cellulose meltblown cloth of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Embodiment 1:

[0030] An embodiment of the present invention provides a superfine fiber recycled material with an electrical gradient structure, comprising the following raw materials in percentage: 86% cellulose pulp, 5% alumina nanopowder, 5% plasticizer (glycerol), 1% surfactant (sodium carboxymethyl cellulose or polyoxyethylene ether), 0.5% antioxidant (vitamin C), and 2.5% nano silicon dioxide.

[0031] The method for preparing a superfine fiber recycled material with an electric gradient structure comprises the following steps:

[0032] S1. Preparation of cellulose stock solution

[0033] The 50% NMMO solution is concentrated under vacuum, and then mixed and stirred with cellulose pulp under vacuum and heating conditions to dissolve, and aluminum oxide nanopowder, plasticizer, surfactant, antioxidant and nano-silicon dioxide are added to the stock solution, and then a clarified cellulose spinning stock solution is obtained. The cellulose pulp needs to be dried at 100°C before stirring for 4 hours; the vacuum degree of vacuum mixing and stirring is 0.095Mpa to 0.1MPa.

[0034] In the above steps, by incorporating aluminum oxide nanopowder with a high dielectric constant, the nanoparticles can serve as charge capture points, which not only improves the charge capture ability of the material's surface, but also increases the material's ability to retain triboelectric charges, thereby increasing the material's surface charge density.

[0035] S2. Forming of cellulose meltblown nonwoven fabrics

[0036] The cellulose stock solution obtained above is poured into a dissolving kettle, and nitrogen is introduced, and extruded through the spinneret holes of the spinneret die head, and the ejected cellulose filaments are stretched and refined by high-speed airflow, and the cellulose filaments are cooled and pre-solidified by spraying, and then the pre-solidified cellulose filaments are self-bonded on the receiving mesh curtain to form a fiber web, and the obtained fiber web is immersed in a coagulation bath to precipitate the solvent, and finally washed, dried, and wound to obtain a cellulose melt-blown cloth. The forming process of the cellulose melt-blown cloth is as follows: Figure 2 As shown;

[0037] S3. Recycling of NMMO solvent

[0038] The coagulation bath after the cellulose filaments are coagulated and the liquid after washing are collected in the above step, and after being treated, the NMMO solvent in the solution is recovered by vacuum distillation.

[0039] In step S1, the concentration of the NMMO solvent after concentration is not less than 80wt%; the NMMO solution is preheated after concentration, and the preheating temperature is the dissolution temperature of cellulose in the solution; the mixing stirring rate of the NMMO solvent and the cellulose pulp is 400rpm; the average polymerization degree of the cellulose pulp is 600bp; and the concentration of the cellulose spinning solution is 3wt%.

[0040] In step S2, the temperature of the spinneret is 110°C, the diameter of the spinneret hole is 0.4 mm, the speed of the high-speed airflow is 30 m / s, at least two spinnerets are provided, and the receiving mesh curtain is spun sequentially through the multiple spinnerets to obtain a fiber web with a gradient structure. When two spinnerets are used, the drafting distance L1 is 20 cm, the spraying distance L2 is 15 cm, the drafting distance L3 is 30 cm, and the spraying distance L4 is 20 cm.

[0041] In step S2, the specific process of cooling and pre-solidifying the cellulose filaments by spraying is as follows:

[0042] Turn on the tap water cooling spray system and maintain the spray pressure at 0.2MPa.

[0043] The S3 step specifically includes the following processes:

[0044] S31. First, the liquid is coarsely filtered using a filter to remove large solid impurities; then a hydrophilic polymer membrane is used for microfiltration to further remove small solid impurities, bacteria and macromolecular colloids;

[0045] S32. Sodium dodecyl sulfate was selected as the surfactant micelle, and NMMO was treated by micelle-enhanced ultrafiltration to remove the degraded residual chains and adsorb metal ions;

[0046] S33. The purified NMMO solution is concentrated by a vacuum distillation process, and the concentrated NMMO solution is purified by distillation to further remove impurities therein and improve the purity of NMMO.

[0047] The recovery rate of NMMO solvent is 97.0%, which can be recycled after purification, and the maximum solubility of the solvent recovered each time in cellulose pulp is not less than 95wt%. The recovery rate is calculated as follows: the mass of NMMO solvent used in the dissolution process is a, the mass of NMMO solvent obtained in the recovery process is b, and the recovery rate is b / a.

[0048] Embodiment 2:

[0049] An embodiment of the present invention provides a microfiber recycled material with an electrical gradient structure, comprising the following raw materials in percentage: 91% cellulose pulp, 3% alumina nanopowder, 3.5% plasticizer (glycerol), 0.5% surfactant (lauroyl ester), 0.3% antioxidant (vitamin E), and 1.7% nano-silicon dioxide.

[0050] The method for preparing a superfine fiber recycled material with an electric gradient structure comprises the following steps:

[0051] S1. Preparation of cellulose stock solution

[0052] The NMMO solution with a concentration of 50% is concentrated under vacuum, and then mixed with cellulose pulp under vacuum and heating conditions to dissolve, and aluminum oxide nanopowder, plasticizer, surfactant, antioxidant and nano-silicon dioxide are added to the stock solution to obtain a clarified cellulose spinning stock solution;

[0053] S2. Forming of cellulose melt-blown nonwoven fabrics

[0054] The cellulose stock solution obtained above is poured into a dissolving kettle, and nitrogen is introduced, and extruded through the spinneret holes of the spinneret die head, and the ejected cellulose filaments are stretched and refined by high-speed airflow, and the cellulose filaments are cooled and pre-solidified by spraying, and then the pre-solidified cellulose filaments are self-bonded on the receiving mesh curtain to form a fiber web, and the obtained fiber web is immersed in a coagulation bath to precipitate the solvent, and finally washed, dried, and wound to obtain a cellulose melt-blown cloth;

[0055] S3. Recycling of NMMO solvent

[0056] The coagulation bath after the cellulose filaments are coagulated and the liquid after washing are collected in the above step, and after being treated, the NMMO solvent in the solution is recovered by vacuum distillation.

[0057] In step S1, the concentration of the concentrated NMMO solvent is not less than 80 wt %; the mixing stirring rate of the NMMO solvent and the cellulose pulp is 300 rpm; the average polymerization degree of the cellulose pulp is 500 bp; and the concentration of the cellulose spinning solution is 6 wt %.

[0058] In step S2, the temperature of the spinneret is 90°C, the diameter of the spinneret hole is 0.35 mm, the speed of the high-speed airflow is 20 m / s, at least two spinnerets are provided, and the receiving mesh curtain is spun sequentially through the multiple spinnerets to obtain a fiber web with a gradient structure. When two spinnerets are used, the drafting distance L1 is 25 cm, the spraying distance L2 is 20 cm, the drafting distance L3 is 50 cm, and the spraying distance L4 is 35 cm.

[0059] In step S2, the specific process of cooling and pre-solidifying the cellulose filaments by spraying is as follows:

[0060] Turn on the tap water spray system and maintain the spray pressure at 0.13MPa.

[0061] The S3 step specifically includes the following processes:

[0062] S31. First, the liquid is coarsely filtered using a filter to remove large solid impurities; then a hydrophilic polymer membrane is used for microfiltration to further remove small solid impurities, bacteria and macromolecular colloids;

[0063] S32. Sodium dodecyl sulfate was selected as the surfactant micelle, and NMMO was treated by micelle-enhanced ultrafiltration to remove the degraded residual chains and adsorb metal ions;

[0064] S33. The purified NMMO solution is concentrated by a vacuum distillation process, and the concentrated NMMO solution is purified by distillation to further remove impurities therein and improve the purity of NMMO.

[0065] Embodiment three:

[0066] An embodiment of the present invention provides a microfiber recycled material with an electrical gradient structure, comprising the following raw materials in percentage: 96% cellulose pulp, 1% alumina nanopowder, 2% plasticizer (glycerol), 0.1% surfactant (lauroyl ester), 0.1% antioxidant (anthocyanin), and 0.8% nano silicon dioxide.

[0067] The method for preparing a superfine fiber recycled material with an electric gradient structure comprises the following steps:

[0068] S1. Preparation of cellulose stock solution

[0069] The NMMO solution with a concentration of 50% is concentrated under vacuum, and then mixed with cellulose pulp under vacuum and heating conditions to dissolve, and aluminum oxide nanopowder, plasticizer, surfactant, antioxidant and nano-silicon dioxide are added to the stock solution to obtain a clarified cellulose spinning stock solution;

[0070] S2. Forming of cellulose melt-blown nonwoven fabrics

[0071] The cellulose stock solution obtained above is poured into a dissolving kettle, and nitrogen is introduced, and extruded through the spinneret holes of the spinneret die head, and the ejected cellulose filaments are stretched and refined by high-speed airflow, and the cellulose filaments are cooled and pre-solidified by spraying, and then the pre-solidified cellulose filaments are self-bonded on the receiving mesh curtain to form a fiber web, and the obtained fiber web is immersed in a coagulation bath to precipitate the solvent, and finally washed, dried, and wound to obtain a cellulose melt-blown cloth;

[0072] S3. Recycling of NMMO solvent

[0073] The coagulation bath after the cellulose filaments are coagulated and the liquid after washing are collected in the above step, and after being treated, the NMMO solvent in the solution is recovered by vacuum distillation.

[0074] In step S1, the concentration of the NMMO solvent after concentration is not less than 80wt%; the NMMO solution is preheated after concentration, the preheating temperature is the dissolution temperature of cellulose in the solution, and the preheating time is 5min; the mixing stirring rate of the NMMO solvent and the cellulose pulp is 150rpm; the average polymerization degree of the cellulose pulp is 400bp; and the concentration of the cellulose spinning solution is 10wt%.

[0075] In step S2, the temperature of the spinneret is 100°C, the diameter of the spinneret hole is 0.3mm, the speed of the high-speed airflow is 10m / s, at least two spinnerets are provided, and the receiving mesh curtain is spun sequentially through the multiple spinnerets to obtain a fiber web with a gradient structure. When two spinnerets are used, the drafting distance L1 is 40cm, the spraying distance L2 is 35cm, the drafting distance L3 is 30cm, and the spraying distance L4 is 25cm.

[0076] In step S2, the specific process of cooling and pre-solidifying the cellulose filaments by spraying is as follows:

[0077] Turn on the tap water spray system and maintain the spray pressure at 0.05MPa.

[0078] The S3 step specifically includes the following processes:

[0079] S31. First, the liquid is coarsely filtered using a filter to remove large solid impurities; then a hydrophilic polymer membrane is used for microfiltration to further remove small solid impurities, bacteria and macromolecular colloids;

[0080] S32. Sodium dodecyl sulfate was selected as the surfactant micelle, and NMMO was treated by micelle-enhanced ultrafiltration to remove the degraded residual chains and adsorb metal ions;

[0081] S33. The purified NMMO solution is concentrated by a vacuum distillation process, and the concentrated NMMO solution is purified by distillation to further remove impurities therein and improve the purity of NMMO.

[0082] Comparative Example:

[0083] The comparative example of the present invention provides a superfine fiber recycled material with an electric gradient structure, which includes the following raw materials in percentage: 86% cellulose pulp, 5% alumina nano powder, 5% plasticizer (glycerol), 1% surfactant (sodium carboxymethyl cellulose or polyoxyethylene ether), 0.5% antioxidant (vitamin C), and 2.5% nano silicon dioxide.

[0084] The method for preparing a superfine fiber recycled material with an electric gradient structure comprises the following steps:

[0085] S1. Preparation of cellulose stock solution

[0086] The NMMO solution with a concentration of 50% is concentrated to 80wt% under vacuum, and then mixed with cellulose pulp under vacuum and heating conditions, stirred and dissolved at a stirring rate of 400rpm, and aluminum oxide nanopowder, plasticizer, surfactant, antioxidant and nano-silica are added to the stock solution to obtain a clarified cellulose spinning stock solution;

[0087] S2. Forming of cellulose meltblown nonwoven fabrics

[0088] The cellulose stock solution obtained above is poured into a homemade dissolution kettle and nitrogen is introduced. It is extruded through the spinneret holes of the spinneret die head. The temperature of the spinneret is 110°C. At the same time, the ejected cellulose filaments are stretched and refined by a high-speed airflow. The speed of the high-speed airflow is 20m / s. The cellulose filaments are then self-adhesively formed into a fiber web on a receiving mesh curtain. The obtained fiber web is immersed in a coagulation bath to precipitate the solvent. Finally, the cellulose melt-blown cloth is obtained by washing, drying, and winding.

[0089] At least two spinnerets are provided, and the distance between the spinneret and the receiving roller is the drafting distance, the drafting distance L1 is 20 cm, and the drafting distance L3 is 30 cm.

[0090] The SEM images of the cellulose melt-blown fabrics obtained in the comparative example and the example 1 are as follows: Figure 1 As shown, a is a cellulose melt-blown cloth prepared in the comparative example without a spray system, and b is a cellulose melt-blown cloth prepared in the embodiment 1 with a spray system. Figure 1 When there is no water mist acting on the spinning jet, the fabric formed looks more like a film. The solution filaments are not solidified during the spinning process and will fuse together when they fall on the receiving device. As can be seen from the figure, when water mist acts on the solution jet, the cellulose solution spray cloth is composed of well-separated fine fibers.

[0091] The cellulose melt-blown fabrics prepared in Examples 1 to 3 and the comparative example were tested for breaking strength and elongation. The melt-blown fabrics were subjected to longitudinal and transverse tensile tests using a universal material testing machine to measure their breaking strength and breaking elongation. The results are shown in the following table:

[0092] Table 1 Breaking strength and elongation of meltblown fabric

[0093]

[0094] It can be seen from the above table that whether spray cooling and pre-solidification are performed has a positive effect on the elongation at break of the meltblown cloth. The longitudinal elongation of the meltblown cloth prepared after spraying is significantly improved, and it is a tough material; while the elongation of the control sample is very small, and it is a brittle material.

[0095] The absorption capacity and absorption efficiency of the cellulose meltblown fabrics prepared in Examples 1 to 3 and the comparative example were tested. First, the samples were weighed, and the mass was recorded as m0. The samples were immersed in the test liquid, taken out after 5 minutes, and hung vertically until no obvious droplets fell on the surface of the samples, and then weighed again and recorded as m1. The absorption capacity was calculated as (m1-m0) / m0.

[0096] Testing method for absorption efficiency: Take 3 pieces of 5cm×5cm fresh pigskin, wash them, evenly apply 1mL of sodium hyaluronate solution on the pigskin, and then cover the samples of the embodiments of the present invention and the control samples on them respectively. After 20 minutes, remove the electret sample and the control sample. Referring to the reverse osmosis test of baby diapers in the first part of the GB / T "Diapers" standard, take 3 pieces of filter paper and cover them on the pigskin respectively, and place a 375g weight block on top to apply a 4kPa pressure to the pigskin, wait for 2 minutes, and absorb the sodium hyaluronate solution remaining on the surface of the pigskin. Then cut the pigskin into pieces, soak it in 50mL of deionized water, and ultrasonically vibrate it for 2 hours to reversely extract the sodium hyaluronate absorbed by the pigskin into the solution. Test the concentration of sodium hyaluronate in the solution and calculate the absorption of sodium hyaluronate by the pigskin. The formula for improving efficiency is: (m 实施例 -m 对比例 ) / m 对比例 .

[0097] Table 2 Mask absorption amount and absorption efficiency

[0098] Test No. Charge capacity(KV) Absorption Improve absorption rate Embodiment 1 1.5 8.0 20 Embodiment 2 1.0 9.5 17 Embodiment 3 0.5 10.5 10 Comparative Example 0.2 6.5 0

[0099] It can be seen from the above table that spray cooling and pre-solidification can improve the absorption efficiency of the meltblown cloth to a certain extent, and as the spray distance increases, the absorption efficiency of the meltblown cloth also increases.

[0100] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A superfine fiber recycled material with an electrical gradient structure, characterized in that: The raw materials include the following percentages: cellulose pulp 86% to 96%, alumina nano powder 1% to 5%, plasticizer 2% to 5%, surfactant 0.1% to 1%, antioxidant 0.1% to 0.5%, and nano silicon dioxide 0.8% to 2.5%.

2. The method for preparing the ultrafine fiber recycled material with electric gradient structure according to claim 1, characterized in that: The following steps are involved: S1. Preparation of cellulose stock solution The NMMO solution with a concentration of 50% is concentrated under vacuum, and then mixed with cellulose pulp under vacuum and heating conditions to dissolve, and aluminum oxide nanopowder, plasticizer, surfactant, antioxidant and nano-silica are added to the stock solution to obtain a clarified cellulose spinning stock solution; S2. Forming of cellulose melt-blown nonwoven fabrics The cellulose stock solution obtained above is poured into a dissolving kettle, and nitrogen is introduced, and extruded through the spinneret holes of the spinneret die head, and the ejected cellulose filaments are stretched and refined by high-speed airflow, and the cellulose filaments are cooled and pre-solidified by spraying, and then the pre-solidified cellulose filaments are self-bonded on the receiving mesh curtain to form a fiber web, and the obtained fiber web is immersed in a coagulation bath to precipitate the solvent, and finally washed, dried, and wound to obtain a cellulose melt-blown cloth; S3. Recycling of NMMO solvent The coagulation bath after the cellulose filaments are coagulated and the liquid after washing are collected in the above step, and after being treated, the NMMO solvent in the solution is recovered by vacuum distillation.

3. The method for preparing the ultrafine fiber recycled material with electric gradient structure according to claim 1, characterized in that: In step S1, the concentration of the NMMO solvent after concentration is not less than 80wt%; the NMMO solution is preheated after concentration, and the preheating temperature is the dissolution temperature of cellulose in the solution; the mixing stirring rate of the NMMO solvent and the cellulose pulp is 150-400rpm; the average polymerization degree of the cellulose pulp is 400-600bp; and the concentration of the cellulose spinning solution is 3-10wt%.

4. The method for preparing the ultrafine fiber recycled material with electric gradient structure according to claim 1, characterized in that: In step S2, the temperature of the spinneret is 90-110°C, and the diameter of the spinneret hole is 0.3-0.4 mm; the speed of the high-speed airflow is 10-30 m / s; there are at least two spinnerets, and the receiving mesh curtain is spun in sequence by multiple spinnerets to obtain a fiber web with a gradient structure; the spray height sprayed by the spray nozzle is the spray distance, which can be adjusted within the range of 15-35 cm, and the distance between the spinneret and the receiving mesh curtain is the drawing distance, which can be adjusted within the range of 20-50 cm.

5. The method for preparing the ultrafine fiber recycled material with electric gradient structure according to claim 1, characterized in that: In step S2, the specific process of cooling and pre-solidifying the cellulose filaments by spraying is as follows: Turn on the tap water spray system and maintain the spray pressure at 0.05-0.2MPa.

6. The method for preparing the ultrafine fiber recycled material with electric gradient structure according to claim 1, characterized in that: The S3 step specifically includes the following processes: S31. First, the liquid is coarsely filtered using a filter to remove large solid impurities; then a hydrophilic polymer membrane is used for microfiltration to further remove small solid impurities, bacteria and macromolecular colloids; S32. Sodium dodecyl sulfate was selected as the surfactant micelle, and NMMO was treated by micelle-enhanced ultrafiltration to remove the degraded residual chains and adsorb metal ions; S33. The purified NMMO solution is concentrated by a vacuum distillation process, and the concentrated NMMO solution is purified by distillation to further remove impurities therein and improve the purity of NMMO.

7. Application of the ultrafine fiber regenerated material obtained by the preparation method according to any one of claims 2 to 6 in facial mask base fabrics, mask substrates, sanitary products, and filter materials, characterized in that: The average fiber diameter of the ultrafine fiber regeneration material is 0.8-5.0 μm, and the charge is 0.5-1.5 Kv. When the ultrafine fiber regeneration material is applied to a facial mask base cloth and applied for 20 minutes, the skin's absorption of essence is increased by 10-20%.

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