A regenerated flash nonwoven fabric and a method for manufacturing the same

Abstract

The application provides a regenerated flash non-woven fabric and a preparation method thereof, and relates to the technical field of recycling and regeneration of waste polymer materials.The non-woven fabric is prepared by using regenerated polyethylene as a main material, adding conventional polyethylene, modified polyester, cyclodextrin modified shell powder and calcium stearate through a flash method, so that the recycling and utilization of waste high-density polyethylene are realized, the utilization rate of waste vinyl chloride is improved, the obtained non-woven fabric has high whiteness, good temperature resistance, high breaking strength, the breaking strength is greater than or equal to 204.7N / 5cm and less than or equal to 247.3N / 5cm, the strength is equivalent to that of a virgin non-woven fabric, and the softness is high.

Description

Technical Field

[0001] This application relates to the field of recycling and regeneration technology of waste polymer materials, and in particular to a recycled flash nonwoven fabric and its preparation method. Background Technology

[0002] With the rapid development of my country's plastics industry, the huge output and consumption have generated a large amount of plastic waste. Improper disposal of plastic waste not only aggravates environmental pollution but also reduces the efficiency of resource recycling. Therefore, the treatment and recycling of plastics has become a solution to alleviate plastic-related problems and a key focus of research for many scholars.

[0003] Currently, commonly used plastics include polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polycarbonate (PC), polyamide (PA), and polyester (PET). Among them, PE has become the second most consumed plastic pipe variety in the world after PVC. PE has a wide range of applications, such as pipes, bottles, barrels, packaging films, and appliance housings. Its production and consumption are enormous, resulting in a large amount of solid waste and harming the natural environment. Unlike biodegradable plastics, PE cannot be processed through composting or natural degradation. It is mainly recycled, separated, washed, dehydrated, and then re-extruded and granulated into chips for secondary applications, thus improving resource utilization efficiency.

[0004] Polyethylene recycling methods mainly include three aspects: direct regeneration of waste polyethylene, modified regeneration, and pyrolysis regeneration. For example, patent CN110062788A discloses a method for purifying waste polyethylene, and patent CN101851363A discloses a method for regenerating waste polyethylene, including the preparation of polyethylene pipes using waste polyethylene, crosslinking agents, and nanomaterials as raw materials. Although some progress has been made in the research on polyethylene recycling, waste polyethylene suffers from problems such as low strength, poor temperature resistance, and low whiteness, resulting in a low recycling rate for polyethylene waste.

[0005] Polyethylene is one of the commonly used raw materials for producing nonwoven fabrics. Its main forming processes include meltblowing, bonding, water / needle punching, and flash evaporation. The conventional flash evaporation process involves dissolving a certain amount of polyethylene in a solvent under high temperature and pressure to create a spinning solution. This solution is then extruded through a spinneret to form ultrafine fiber bundles. These bundles are electrostatically separated to form a fiber web, which is finally thermally rolled to form nonwoven fabric. Currently, there are proposals to use waste polyethylene to produce nonwoven fabrics, but the resulting nonwoven fabrics have significant differences in strength, temperature resistance, and whiteness compared to virgin nonwoven fabrics, failing to meet market demands. Therefore, researching how to utilize waste polyethylene to produce high-performance nonwoven fabrics is essential. Summary of the Invention

[0006] The purpose of this application is to address the shortcomings of existing technologies by providing a recycled flash-evaporated nonwoven fabric and its preparation method. This application recycles waste high-density polyethylene to produce recycled polyethylene masterbatch, which is then compounded with polyethylene, polyester, and additives. Nonwoven fabric is then produced by flash evaporation. This not only realizes the recycling of waste high-density polyethylene and improves the utilization rate of waste vinyl chloride, but also results in nonwoven fabric with high whiteness, good temperature resistance, and high strength.

[0007] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0008] A recycled flash nonwoven fabric, by weight, comprises the following raw materials: ≥60 parts and ≤80 parts of recycled polyethylene, ≥10 parts and ≤20 parts of polyethylene, ≥5 parts and ≤15 parts of modified polyester, ≥2 parts and ≤8 parts of cyclodextrin-modified shell powder, and ≥0.02 parts and ≤0.2 parts of calcium stearate, wherein the modified polyester is obtained by reacting an aliphatic diol with a diacid, the diacid including aliphatic diacid, vanillic acid and itaconic anhydride.

[0009] Preferably, the above-mentioned recycled flash nonwoven fabric comprises, by weight, the following raw materials: 65 parts or more and 75 parts of recycled polyethylene, 12 parts or more and 18 parts of polyethylene, 8 parts or more and 12 parts of modified polyester, 3 parts or more and 5 parts of cyclodextrin-modified shell powder, and 0.05 parts or more and 0.1 parts of calcium stearate.

[0010] More preferably, the above-mentioned recycled flash nonwoven fabric, by weight, comprises the following raw materials: 68 parts or more and 70 parts of recycled polyethylene, 15 parts or more and 16 parts of polyethylene, 10 parts or more and 12 parts of modified polyester, 4 parts or more and 5 parts of cyclodextrin-modified shell powder, and 0.05 parts or more and 0.1 parts of calcium stearate.

[0011] Furthermore, the basis weight of the aforementioned recycled flash nonwoven fabric is greater than or equal to 60 g / m². 2 And less than or equal to 70g / m 2 .

[0012] Furthermore, in the above-mentioned modified polyester, the aliphatic diol is selected from at least one of ethylene glycol, 1,2-propanediol, 2,3-butanediol, 2-methyl-2,3-butanediol, 2,3-dimethyl-2,3-butanediol, 4-methyl-2,3-pentanediol, and diethylene glycol, and the aliphatic diacid is selected from at least one of succinic acid, glutaric acid, and adipic acid.

[0013] Furthermore, in the above-mentioned modified polyester, the amount of diacid is greater than or equal to 1.1 moles and less than or equal to 1.5 moles relative to 1 mole of aliphatic diol.

[0014] Furthermore, in the above-mentioned modified polyester, in 1 mole of dicarboxylic acid, the proportion of aliphatic diacid is greater than or equal to 70% and less than or equal to 80%, the proportion of vanillic acid is greater than or equal to 2% and less than or equal to 10%, and the proportion of itaconic anhydride is greater than or equal to 10% and less than or equal to 28%.

[0015] Preferably, in the modified polyester, in 1 mole of dicarboxylic acid, the proportion of aliphatic diacid is greater than or equal to 75% and less than or equal to 78%, the proportion of vanillic acid is greater than or equal to 5% and less than or equal to 8%, and the proportion of itaconic anhydride is greater than or equal to 14% and less than or equal to 20%.

[0016] More preferably, in the above-mentioned modified polyester, in 1 mole of dicarboxylic acid, the proportion of aliphatic diacid is greater than or equal to 76% and less than or equal to 78%, the proportion of vanillic acid is greater than or equal to 6% and less than or equal to 7%, and the proportion of itaconic anhydride is greater than or equal to 15% and less than or equal to 18%.

[0017] Furthermore, the above-mentioned polyester is specifically prepared by the following method:

[0018] Under nitrogen protection, the dehydrated aliphatic diol and diacid are mixed, a catalyst is added, and the mixture is first reacted at a temperature greater than or equal to 150°C and less than or equal to 160°C for a reaction time greater than or equal to 0.5 h and less than or equal to 1 h. Then the temperature is increased to greater than or equal to 175°C and less than or equal to 190°C and the reaction continues for a reaction time greater than or equal to 1 h and less than or equal to 3 h. Finally, the mixture is polycondensed at a temperature greater than or equal to 190°C and less than or equal to 210°C for a time greater than or equal to 5 h and less than or equal to 12 h to obtain the polyester.

[0019] Preferably, the catalyst is a titanium-based catalyst, more preferably at least one selected from tetrabutyl titanate, tetraisopropyl titanate, titanium dioxide, potassium fluorotitanate, and titanium carboxylate.

[0020] Furthermore, the above-mentioned cyclodextrin-modified shell powder was prepared by the following method:

[0021] Shell powder was placed in an acidic solution and microwaved. After removal, it was washed and dried to obtain pretreated shell powder. Then, β-cyclodextrin and an aqueous solution of chloroacetic acid were added to a NaOH solution and reacted at a temperature greater than or equal to 50°C and less than or equal to 60°C for a reaction time greater than or equal to 3 hours and less than or equal to 5 hours. After the reaction was completed, the pH was adjusted to greater than or equal to 5 and less than or equal to 7, and excess methanol was added. The mixture was filtered and dried to obtain carboxymethyl β-cyclodextrin. Then, carboxymethyl β-cyclodextrin was added to acetone and mixed well. Pretreated shell powder was added and the reaction was continued at a temperature greater than or equal to 30°C and less than or equal to 60°C for a reaction time greater than or equal to 2 hours and less than or equal to 5 hours. After the reaction was completed, the acetone was removed by vacuum drying to obtain cyclodextrin-modified shell powder.

[0022] Preferably, the acid solution is at least one of hydrochloric acid, nitric acid, and citric acid, and the mass fraction of the acid solution is greater than or equal to 10% and less than or equal to 20%.

[0023] Preferably, the microwave heating conditions are: power greater than or equal to 400W and less than or equal to 600W, frequency greater than or equal to 1.0GHz and less than or equal to 1.5GHz, temperature greater than or equal to 150℃ and less than or equal to 160℃, and time greater than or equal to 30min and less than or equal to 60min.

[0024] Preferably, the mass fraction of the aqueous chloroacetic acid solution is greater than or equal to 15% and less than or equal to 20%, and the amount of chloroacetic acid used is greater than or equal to 0.6 times and less than or equal to 0.75 times the mass of β-cyclodextrin.

[0025] Preferably, the amount of carboxymethyl β-cyclodextrin used is greater than or equal to 0.2 parts and less than or equal to 0.4 parts relative to 1 part by weight of shell powder.

[0026] More preferably, the amount of carboxymethyl β-cyclodextrin used is greater than or equal to 0.25 parts and less than or equal to 0.3 parts relative to 1 part by weight of shell powder.

[0027] This application first pre-treats the shell powder, resulting in an increase in active groups on the surface of the pre-treated shell powder. However, the compatibility between the pre-treated shell powder and the polymer is poor. This application utilizes carboxymethylated cyclodextrin to react with the shell powder. The cyclodextrin enters the pores of the shell powder and coats the surface, improving the compatibility with polyethylene. When nonwoven fabrics are prepared with recycled polyethylene materials, the strength of the nonwoven fabric can be significantly improved without reducing its flexibility. It also helps to improve the whiteness of the nonwoven fabric, making up for the defect of low whiteness in nonwoven fabrics prepared from recycled polyethylene.

[0028] This application also provides a recycled flash nonwoven fabric and its preparation method, including the following steps: first, waste high-density polyethylene is recycled to make recycled polyethylene masterbatch, then melted to obtain recycled polyethylene spinning solution, then the solvent is preheated, cyclodextrin modified shell powder and calcium stearate are added and ultrasonically mixed, then polyethylene and modified polyester are added and mixed to obtain a first spinning solution, the first spinning solution is mixed with the recycled polyethylene spinning solution, flash spinning is performed, web is laid, and hot pressing is performed to obtain the nonwoven fabric.

[0029] Furthermore, the steps for recycling waste high-density polyethylene to produce recycled polyethylene masterbatch include: cleaning and crushing the waste high-density polyethylene, soaking it in a soaking solution, washing it with water and drying it, raising the temperature to greater than or equal to 140°C and less than or equal to 150°C, and then melt-extruding it to obtain recycled polyethylene masterbatch.

[0030] Preferably, during the preparation of the recycled polyethylene spinning solution, when the temperature is increased by 20°C or more and 30°C or less, a heat preservation process is performed for 30 minutes or more and 50 minutes or less.

[0031] More preferably, during the preparation of the recycled polyethylene spinning solution, when the temperature is increased by more than or equal to 25°C and less than or equal to 30°C, the temperature is kept warm for more than or equal to 35 minutes and less than or equal to 40 minutes.

[0032] Preferably, the soaking solution, by mass percentage, contains a surfactant content of ≥6% and ≤10%, a salt content of ≥0.5% and ≤1%, a malic acid content of ≥1% and ≤3%, and the remainder is water. Preferably, the surfactant is selected from at least one of dodecyl sulfobetaine, dodecyl ethoxysulfobetaine, dodecyl hydroxypropyl sulfobetaine, dodecyl sulfopropyl betaine, tetradecanoamide propyl hydroxypropyl sulfobetaine, decyl hydroxypropyl sulfobetaine, tetradecyl dihydroxyethylamine oxide, and cocamidopropylamine oxide.

[0033] Preferably, the amount of soaking solution used is greater than or equal to 8 times and less than or equal to 15 times the mass of the waste high-density polyethylene plastic.

[0034] Preferably, the temperature during the soaking process is greater than or equal to 50°C and less than or equal to 60°C, and the time is greater than or equal to 1 hour and less than or equal to 3 hours.

[0035] Furthermore, the solvent is selected from at least one of aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, unsaturated hydrocarbons, halogenated hydrocarbons, alcohols, esters, ethers, and fluorocarbons, preferably difluorochloromethane and / or tetrafluorodichloroethane.

[0036] Furthermore, the preheating temperature is greater than or equal to 80℃ and less than or equal to 100℃, and the preheating time is greater than or equal to 0.5h and less than or equal to 2h.

[0037] Preferably, the preheating temperature is greater than or equal to 90°C and less than or equal to 95°C, and the preheating time is greater than or equal to 1 hour and less than or equal to 1.5 hours.

[0038] Furthermore, the flash spinning temperature is greater than or equal to 180℃ and less than or equal to 230℃, and the hot pressing temperature is greater than or equal to 105℃ and less than or equal to 120℃.

[0039] Compared with the prior art, this application has the following beneficial effects:

[0040] 1. This application uses recycled polyethylene as raw material to prepare nonwoven fabric, realizing the recycling and reuse of polyethylene waste. The method is simple and low in cost.

[0041] 2. The nonwoven fabric obtained in this application has high whiteness and good temperature resistance. The nonwoven fabric obtained in this application has high strength, with a breaking strength greater than or equal to 204.7 N / 5 cm and less than or equal to 247.3 N / 5 cm, which can reach the strength of virgin nonwoven fabric. It also has high softness, with a longitudinal softness greater than or equal to 21.4 mN and less than or equal to 23.3 mN, and a transverse softness greater than or equal to 23.1 mN and less than or equal to 24.3 mN. It can be applied to the development of civilian products such as clothing, furniture or other daily necessities.

[0042] 3. This application uses polyethylene, modified polyester, and recycled polyethylene as the main materials. The introduction of specific vanillic acid and itaconic anhydride segments into the modified polyester helps to improve the poor toughness and low strength of recycled polyethylene, thus enhancing the mechanical properties of the resulting nonwoven fabric. The addition of polyester can also regulate the structure of fibers spun by flash evaporation, improving the temperature resistance of the nonwoven fabric and increasing its processability during flash evaporation, thereby compensating for the poor temperature resistance of recycled polyethylene.

[0043] 4. This application also includes cyclodextrin-modified shell powder. Compared to untreated shell powder, this invention modifies the surface of the shell powder, improving its compatibility with polymers and resulting in a more uniform nonwoven fabric. This helps improve the temperature resistance and mechanical properties of the nonwoven fabric without significantly affecting its feel. The addition of cyclodextrin-modified shell powder, combined with benzoxazole thiophene-based calcium stearate, can also significantly improve the whiteness of the nonwoven fabric, compensating for the low whiteness of recycled polyethylene.

[0044] 5. In the preparation process of this application, polyethylene waste is melted by programmed heating to improve its mechanical strength. The solvent is preheated first and then modified polyester and cyclodextrin modified shell powder are added and mixed, which helps to further improve the mechanical properties and temperature resistance of the nonwoven fabric. Attached Figure Description

[0045] Figure 1These are the infrared spectra of unmodified shell powder and cyclodextrin-modified shell powder in Example 1 of this application. Detailed Implementation

[0046] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of this application, but do not limit this application in any way. The following content is merely an exemplary description of the scope of protection claimed in this application, and those skilled in the art can make various changes and modifications to the invention based on the disclosed content, which should also fall within the scope of protection claimed in this application.

[0047] The present application will be further described below by way of specific embodiments. Unless otherwise specified, all chemical reagents used in the embodiments of this application are obtained through conventional commercial means.

[0048] Example 1: Nonwoven fabric #1

[0049] This embodiment provides a nonwoven fabric comprising the following raw materials: 60 parts recycled polyethylene, 20 parts polyethylene, 5 parts modified polyester, 2 parts cyclodextrin-modified shell powder and 0.05 parts 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene.

[0050] Specifically, the polyester is prepared by the following method: Under nitrogen protection, dehydrated 2,3-butanediol and a diacid are mixed at a molar ratio of 1:1.1, and tetrabutyl titanate (added at 0.2% of the mass of the diol) is added. The mixture is first reacted at 150°C for 1 hour, then the temperature is raised to 175°C and the reaction continues for 3 hours. Finally, it undergoes polycondensation at 190°C for 12 hours to obtain the polyester. In 1 mole of the diacid, the proportion of succinic acid is 70%, the proportion of vanillic acid is 2%, and the proportion of itaconic anhydride is 28%.

[0051] Specifically, cyclodextrin-modified shell powder was prepared by the following method: Shell powder was placed in a 10% (w / w) nitric acid solution and microwave-treated (400W power, 1.0GHz frequency, 150℃ temperature, 60min). After removal, it was washed and dried to obtain pretreated shell powder. β-cyclodextrin and a 15% (w / w) aqueous solution of chloroacetic acid were added to a sufficient amount of NaOH solution and reacted. The mass ratio of β-cyclodextrin to chloroacetic acid was 1:0.6. The reaction was carried out at 50℃ for 5 hours. The pH was adjusted to 5, and excess methanol was added. The mixture was filtered and dried to obtain carboxymethyl β-cyclodextrin. Carboxymethyl β-cyclodextrin was added to a sufficient amount of acetone and mixed well. The pretreated shell powder was then added, with a mass ratio of shell powder to carboxymethyl β-cyclodextrin of 10:2. The reaction was carried out at 30℃ for 5 hours. After the reaction was complete, the acetone was removed by vacuum drying to obtain cyclodextrin-modified shell powder. Infrared spectroscopy was performed on the shell powder before and after modification. The infrared spectra are shown below. Figure 1As shown in the figure. It can be seen from the figure that, compared to unmodified shell powder, cyclodextrin-modified shell powder has a higher content of [value missing] at 2847 cm⁻¹. -1 2910cm -1 A new peak appeared nearby, which is a characteristic peak of -CH3 and -CH2, at 1589 cm⁻¹. -1 1422cm -1 The nearby peaks are characteristic of ether bonds, which are characteristic of carboxymethyl β-cyclodextrin. This indicates that carboxymethyl β-cyclodextrin has been successfully grafted onto the shell powder.

[0052] This embodiment provides a recycled flash-evaporated nonwoven fabric and its preparation method, including the following steps:

[0053] (1) Waste high-density polyethylene (HDPE) was cleaned, crushed, and soaked in a soaking solution. It was then washed with water and dried, and melt-extruded at 140°C to obtain recycled polyethylene masterbatch. During the heating process, the temperature was maintained for 30 minutes for every 20°C increase. The soaking solution, by mass percentage, contained 10% surfactant, 0.5% salt, and 1% malic acid, with the remainder being water. The mass ratio of waste HDPE plastic to the soaking solution was 1:15, and the soaking temperature was 60°C for 1 hour.

[0054] (2) Preheat difluorochloromethane at 80°C for 2 hours, add cyclodextrin-modified shell powder and calcium stearate and mix ultrasonically, then add polyethylene and modified polyester and mix to obtain the first spinning solution. Based on 10 parts by weight of recycled polyethylene, the amount of polyester added is 2 parts by weight, the amount of cyclodextrin-modified shell powder added is 0.2 parts by weight, and the amount of solvent added is 70 parts by weight.

[0055] (3) Melt the recycled polyethylene and then add it to the recycled polyethylene spinning solution obtained in step (2) to obtain the spinning solution. After mixing, flash spinning is performed to obtain flash fiber. Then, web is laid and hot-pressed to obtain the nonwoven fabric 1#.

[0056] Example 2: Nonwoven fabric #2

[0057] This embodiment provides a nonwoven fabric comprising the following raw materials: 65 parts recycled polyethylene, 18 parts polyethylene, 8 parts modified polyester, 3 parts cyclodextrin-modified shell powder and 0.05 parts 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene.

[0058] Specifically, the polyester is prepared by the following method: Under nitrogen protection, dehydrated 2,3-butanediol and a diacid are mixed at a molar ratio of 1:1.1, and tetrabutyl titanate (added at 0.2% of the mass of the diol) is added. The mixture is first reacted at 150°C for 1 hour, then the temperature is raised to 175°C and the reaction continues for 3 hours. Finally, it undergoes polycondensation at 190°C for 12 hours to obtain the polyester. In 1 mole of the diacid, the proportion of succinic acid is 75%, the proportion of vanillic acid is 5%, and the proportion of itaconic anhydride is 20%.

[0059] Specifically, cyclodextrin-modified shell powder is prepared by the following method: Shell powder is placed in a 10% (w / w) nitric acid solution and microwave-treated (400W power, 1.0GHz frequency, 150℃ temperature, 60min). After removal, it is washed and dried to obtain pretreated shell powder. β-cyclodextrin and a 15% (w / w) aqueous solution of chloroacetic acid are added to a sufficient amount of NaOH solution for reaction. The mass ratio of β-cyclodextrin to chloroacetic acid is 1:0.6. The reaction is carried out at 50℃ for 5h. The pH is adjusted to 5, and then excess methanol is added. After filtration and drying, carboxymethyl β-cyclodextrin is obtained. Carboxymethyl β-cyclodextrin is added to a sufficient amount of acetone and mixed well. The pretreated shell powder is then added, with a mass ratio of shell powder to carboxymethyl β-cyclodextrin of 10:2.5. The reaction is carried out at 30℃ for 5h. After the reaction is complete, the acetone is removed by vacuum drying to obtain cyclodextrin-modified shell powder.

[0060] This embodiment provides a recycled flash-evaporated nonwoven fabric and its preparation method, including the following steps:

[0061] (1) Waste high-density polyethylene (HDPE) was cleaned, crushed, and soaked in a soaking solution. It was then washed with water and dried, and melt-extruded at 140°C to obtain recycled polyethylene masterbatch. During the heating process, the temperature was maintained for 30 minutes for every 20°C increase. The soaking solution, by mass percentage, contained 10% surfactant, 0.5% salt, and 1% malic acid, with the remainder being water. The mass ratio of waste HDPE plastic to the soaking solution was 1:15, and the soaking temperature was 60°C for 1 hour.

[0062] (2) Preheat difluorochloromethane at 80°C for 2 hours, add cyclodextrin-modified shell powder and calcium stearate and mix ultrasonically, then add polyethylene and modified polyester and mix to obtain the first spinning solution. Based on 10 parts by weight of recycled polyethylene, the amount of polyester added is 2 parts by weight, the amount of cyclodextrin-modified shell powder added is 0.2 parts by weight, and the amount of solvent added is 70 parts by weight.

[0063] (3) Melt the recycled polyethylene, and then add it to the recycled polyethylene spinning solution obtained in step (2) to obtain the spinning solution. After mixing, flash spinning is performed to obtain flash fiber. Then, web is laid and hot-pressed to obtain the nonwoven fabric 2#.

[0064] Example 3: Nonwoven fabric #3

[0065] This embodiment provides a nonwoven fabric comprising the following raw materials: 68 parts recycled polyethylene, 16 parts polyethylene, 10 parts modified polyester, 4 parts cyclodextrin-modified shell powder, and 0.05 parts 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene.

[0066] Specifically, the polyester is prepared by the following method: Under nitrogen protection, dehydrated 1,2-propanediol and a diacid are mixed at a molar ratio of 1:1.5, and tetrabutyl titanate (added at 0.2% of the mass of the diol) is added. The mixture is first reacted at 160°C for 0.5 h, then heated to 190°C and reacted for another 1 h, followed by polycondensation at 210°C for 5 h to obtain the polyester. In 1 mole of the diacid, the proportion of glutaric acid is 76%, the proportion of vanillic acid is 6%, and the proportion of itaconic anhydride is 18%.

[0067] Specifically, the cyclodextrin-modified shell powder is prepared by the following method: Shell powder is placed in a 10% (w / w) nitric acid solution and microwave-treated (600W power, 1.5GHz frequency, 160℃ temperature, 30min). After removal, it is washed and dried to obtain pretreated shell powder. β-cyclodextrin and a 20% (w / w) aqueous solution of chloroacetic acid are added to a sufficient amount of NaOH solution for reaction. The mass ratio of β-cyclodextrin to chloroacetic acid is 1:0.75. The reaction is carried out at 50℃ for 5h. The pH is adjusted to 5, and then excess methanol is added. After filtration and drying, carboxymethyl β-cyclodextrin is obtained. Carboxymethyl β-cyclodextrin is added to a sufficient amount of acetone and mixed well. The pretreated shell powder is then added, with a mass ratio of shell powder to carboxymethyl β-cyclodextrin of 10:3. The reaction is carried out at 60℃ for 2h. After the reaction is complete, the acetone is removed by vacuum drying to obtain the cyclodextrin-modified shell powder.

[0068] This embodiment also provides another method for preparing recycled flash nonwoven fabric, including the following steps:

[0069] (1) Waste high-density polyethylene (HDPE) was cleaned, crushed, and soaked in a soaking solution. It was then washed with water and dried, and melt-extruded at 160°C to obtain recycled polyethylene masterbatch. During the heating process, the temperature was maintained for 30 minutes for every 25°C increase. The soaking solution, by mass percentage, contained 6% surfactant, 1% salt, and 3% malic acid, with the remainder being water. The mass ratio of waste HDPE plastic to the soaking solution was 1:8, and the soaking temperature was 50°C for 3 hours.

[0070] (2) Preheat difluorochloromethane at 90°C for 1.5 h, add cyclodextrin-modified shell powder and calcium stearate and mix ultrasonically, then add polyethylene and modified polyester and mix to obtain the first spinning solution. Based on 10 parts by weight of recycled polyethylene, the amount of polyester added is 4 parts by weight, the amount of cyclodextrin-modified shell powder added is 0.8 parts by weight, and the amount of solvent added is 100 parts by weight.

[0071] (3) Melt the recycled polyethylene and then add it to the recycled polyethylene spinning solution obtained in step (2) to obtain the spinning solution. After mixing, flash spinning is performed to obtain flash fiber. Then, web is laid and hot-pressed to obtain the nonwoven fabric 3#.

[0072] Example 4: Nonwoven fabric #4

[0073] This embodiment provides a nonwoven fabric comprising the following raw materials: 70 parts recycled polyethylene, 15 parts polyethylene, 12 parts modified polyester, 5 parts cyclodextrin-modified shell powder, and 0.1 parts 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene.

[0074] Specifically, the polyester is prepared by the following method: Under nitrogen protection, dehydrated 1,2-propanediol and a diacid are mixed at a molar ratio of 1:1.5, and tetrabutyl titanate (added at 0.2% of the mass of the diol) is added. The mixture is first reacted at 160°C for 0.5 h, then heated to 190°C and reacted for another 1 h, followed by polycondensation at 210°C for 5 h to obtain the polyester. In 1 mole of the diacid, the proportion of glutaric acid is 78%, the proportion of vanillic acid is 7%, and the proportion of itaconic anhydride is 15%.

[0075] Specifically, the cyclodextrin-modified shell powder is prepared by the following method: Shell powder is placed in a 10% (w / w) nitric acid solution and microwave-treated (600W power, 1.5GHz frequency, 160℃ temperature, 30min). After removal, it is washed and dried to obtain pretreated shell powder. β-cyclodextrin and a 20% (w / w) aqueous solution of chloroacetic acid are added to a sufficient amount of NaOH solution for reaction. The mass ratio of β-cyclodextrin to chloroacetic acid is 1:0.75. The reaction is carried out at 50℃ for 5h. The pH is adjusted to 5, and then excess methanol is added. After filtration and drying, carboxymethyl β-cyclodextrin is obtained. Carboxymethyl β-cyclodextrin is added to a sufficient amount of acetone and mixed well. The pretreated shell powder is then added, with a mass ratio of shell powder to carboxymethyl β-cyclodextrin of 10:3. The reaction is carried out at 60℃ for 2h. After the reaction is complete, the acetone is removed by vacuum drying to obtain the cyclodextrin-modified shell powder.

[0076] This embodiment also provides another method for preparing recycled flash nonwoven fabric, including the following steps:

[0077] (1) Waste high-density polyethylene (HDPE) was cleaned, crushed, and soaked in a soaking solution. It was then washed with water and dried, and melt-extruded at 160°C to obtain recycled polyethylene masterbatch. During the heating process, the temperature was maintained for 30 minutes for every 25°C increase. The soaking solution, by mass percentage, contained 6% surfactant, 1% salt, and 3% malic acid, with the remainder being water. The mass ratio of waste HDPE plastic to the soaking solution was 1:8, and the soaking temperature was 50°C for 3 hours.

[0078] (2) Preheat difluorochloromethane at 90°C for 1.5 h, add cyclodextrin-modified shell powder and calcium stearate and ultrasonically mix, then add polyethylene and modified polyester and mix to obtain the first spinning solution. Based on 10 parts by weight of recycled polyethylene, the amount of polyester added is 4 parts by weight, the amount of cyclodextrin-modified shell powder added is 0.8 parts by weight, and the amount of solvent added is 100 parts by weight.

[0079] (3) Melt the recycled polyethylene and then add it to the recycled polyethylene spinning solution obtained in step (2) to obtain the spinning solution. After mixing, flash spinning is performed to obtain flash fiber. Then, web is laid and hot-pressed to obtain the nonwoven fabric 4#.

[0080] Example 5: Nonwoven fabric #5

[0081] This embodiment provides a nonwoven fabric comprising the following raw materials: 75 parts recycled polyethylene, 12 parts polyethylene, 12 parts modified polyester, 5 parts cyclodextrin-modified shell powder, and 0.1 parts 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene.

[0082] Specifically, the polyester is prepared by the following method: Under nitrogen protection, dehydrated 1,2-propanediol and a diacid are mixed at a molar ratio of 1:1.5, and tetrabutyl titanate (added at 0.2% of the mass of the diol) is added. The mixture is first reacted at 160°C for 0.5 h, then heated to 190°C and reacted for another 1 h, followed by polycondensation at 210°C for 5 h to obtain the polyester. In 1 mole of the diacid, the proportion of glutaric acid is 78%, the proportion of vanillic acid is 8%, and the proportion of itaconic anhydride is 14%.

[0083] Specifically, the cyclodextrin-modified shell powder is prepared by the following method: Shell powder is placed in a 10% nitric acid solution and microwave-treated (600W power, 1.5GHz frequency, 160℃ temperature, 30min). After removal, it is washed and dried to obtain pretreated shell powder. β-cyclodextrin and a 20% chloroacetic acid aqueous solution are added to a sufficient amount of NaOH solution for reaction. The mass ratio of β-cyclodextrin to chloroacetic acid is 1:0.75. The reaction is carried out at 50℃ for 5h. The pH is adjusted to 5, and then excess methanol is added. The mixture is filtered and dried to obtain carboxymethyl β-cyclodextrin. Carboxymethyl β-cyclodextrin is added to a sufficient amount of acetone and mixed well. The pretreated shell powder is then added, with a mass ratio of shell powder to carboxymethyl β-cyclodextrin of 10:4. The mixture is reacted at 60℃ for 2h. After the reaction is complete, the acetone is removed by vacuum drying to obtain the cyclodextrin-modified shell powder.

[0084] This embodiment also provides another method for preparing recycled flash nonwoven fabric, including the following steps:

[0085] (1) Waste high-density polyethylene (HDPE) plastic was cleaned, crushed, and soaked in a soaking solution. It was then washed, dried, and melt-extruded at 160°C to obtain recycled polyethylene masterbatch. During the heating process, the temperature was maintained for 40 minutes for every 30°C increase. The soaking solution, by mass percentage, contained 6% surfactant, 1% salt, and 3% malic acid, with the remainder being water. The mass ratio of waste HDPE plastic to the soaking solution was 1:8. The soaking temperature was 50°C, and the soaking time was 3 hours.

[0086] (2) Preheat difluorochloromethane at 95°C for 1 hour, add cyclodextrin-modified shell powder and calcium stearate and ultrasonically mix, then add polyethylene and modified polyester and mix to obtain the first spinning solution. Based on 10 parts by weight of recycled polyethylene, the amount of polyester added is 4 parts by weight, the amount of cyclodextrin-modified shell powder added is 0.8 parts by weight, and the amount of solvent added is 100 parts by weight.

[0087] (3) Melt the recycled polyethylene, and then add it to the recycled polyethylene spinning solution obtained in step (2) to obtain the spinning solution. After mixing, flash spinning is performed to obtain flash fiber. Then, web is laid and hot-pressed to obtain the nonwoven fabric 5#.

[0088] Example 6: Nonwoven fabric #6

[0089] This embodiment provides a nonwoven fabric comprising the following raw materials: 80 parts recycled polyethylene, 10 parts polyethylene, 15 parts modified polyester, 8 parts cyclodextrin-modified shell powder, and 0.2 parts 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene.

[0090] Specifically, the polyester is prepared by the following method: Under nitrogen protection, dehydrated 1,2-propanediol and a diacid are mixed at a molar ratio of 1:1.5, and tetrabutyl titanate (added at 0.2% of the mass of the diol) is added. The mixture is first reacted at 160°C for 0.5 h, then heated to 190°C and reacted for another 1 h, followed by polycondensation at 210°C for 5 h to obtain the polyester. In 1 mole of the diacid, the proportions of glutaric acid are 80%, vanillic acid is 10%, and itaconic anhydride is 10%.

[0091] Specifically, cyclodextrin-modified shell powder is prepared by the following method: Shell powder is placed in a 10% (w / w) nitric acid solution and microwave-treated (600W power, 1.5GHz frequency, 160℃ temperature, 30min). After removal, it is washed and dried to obtain pretreated shell powder. β-Cyclodextrin and a 20% (w / w) aqueous solution of chloroacetic acid are added to a sufficient amount of NaOH solution and reacted. The mass ratio of β-cyclodextrin to chloroacetic acid is 1:0.75. The reaction is carried out at 50℃ for 5 hours, the pH is adjusted to 5, excess methanol is added, the mixture is filtered, and dried to obtain carboxymethyl β-cyclodextrin. Carboxymethyl β-cyclodextrin is added to a sufficient amount of acetone and mixed well. The pretreated shell powder is then added, with a mass ratio of shell powder to carboxymethyl β-cyclodextrin of 10:4. The reaction is carried out at 60℃ for 2 hours. After the reaction is complete, the acetone is removed by vacuum drying to obtain cyclodextrin-modified shell powder.

[0092] This embodiment also provides another method for preparing recycled flash nonwoven fabric, including the following steps:

[0093] (1) Waste high-density polyethylene (HDPE) plastic was cleaned, crushed, and soaked in a soaking solution. It was then washed, dried, and melt-extruded at 160°C to obtain recycled polyethylene masterbatch. During the heating process, the temperature was maintained for 50 minutes for every 30°C increase. The soaking solution, by mass percentage, contained 6% surfactant, 1% salt, and 3% malic acid, with the remainder being water. The mass ratio of waste HDPE plastic to the soaking solution was 1:8. The soaking temperature was 50°C, and the soaking time was 3 hours.

[0094] (2) Preheat difluorochloromethane at 100°C for 0.5 h, add cyclodextrin-modified shell powder and calcium stearate and ultrasonically mix, then add polyethylene and modified polyester and mix to obtain the first spinning solution. Based on 10 parts by weight of recycled polyethylene, the amount of polyester added is 4 parts by weight, the amount of cyclodextrin-modified shell powder added is 0.8 parts by weight, and the amount of solvent added is 100 parts by weight.

[0095] (3) Melt the recycled polyethylene and then add it to the recycled polyethylene spinning solution obtained in step (2) to obtain the spinning solution. After mixing, flash spinning is performed to obtain flash fiber. Then, web is laid and hot-pressed to obtain the nonwoven fabric 6#.

[0096] Comparative Example 1: Non-woven fabric #7

[0097] This comparative example provides another nonwoven fabric (denoted as 7#), whose composition is basically the same as that of Example 3. The only difference is that in the preparation process of the modified polyester in this comparative example, the proportion of glutaric acid in 1 mole of dicarboxylic acid is 90%, the proportion of vanillic acid is 1%, and the proportion of itaconic anhydride is 9%.

[0098] Comparative Example 2: Non-woven fabric #8

[0099] This comparative example provides another nonwoven fabric (denoted as 8#), whose composition is basically the same as that of Example 3. The only difference is that in the preparation process of the modified polyester in this comparative example, the proportion of glutaric acid in 1 mole of dicarboxylic acid is 60%, the proportion of vanillic acid is 10%, and the proportion of itaconic anhydride is 30%.

[0100] Comparative Example 3: Non-woven fabric #9

[0101] This comparative example provides another nonwoven fabric (denoted as 9#), whose composition is basically the same as that of Example 3. The only difference is that vanillic acid was not added during the preparation of the modified polyester in this comparative example, and glutaric acid was used to make up the amount of vanillic acid.

[0102] Comparative Example 4: Non-woven fabric #10

[0103] This comparative example provides another nonwoven fabric (denoted as 10#), whose composition is basically the same as that of Example 3. The only difference is that this comparative example provides another recycled flash nonwoven fabric and its preparation method. In the polyester preparation process of this comparative example, itaconic anhydride was not added, and the amount of itaconic anhydride was made up with glutaric acid.

[0104] Comparative Example 5: Non-woven fabric #11

[0105] This comparative example provides another nonwoven fabric (denoted as 11#), whose composition is basically the same as that of Example 3. The only difference is that this comparative example provides another recycled flash nonwoven fabric and its preparation method. In the polyester preparation process of this comparative example, itaconic anhydride and vanillic acid are not added, and the total amount of dicarboxylic acid remains unchanged.

[0106] Comparative Example 6: Non-woven fabric #12

[0107] This comparative example provides another nonwoven fabric (denoted as 12#), whose composition is basically the same as that of Example 3. The only difference is that this comparative example provides another recycled flash nonwoven fabric and its preparation method. This comparative example uses pretreated shell powder instead of cyclodextrin modified shell powder.

[0108] Comparative Example 7: Nonwoven Fabric #13

[0109] This comparative example provides another nonwoven fabric (denoted as 13#), whose composition is basically the same as that of Example 3, except that cyclodextrin-modified shell powder was not added in this comparative example.

[0110] Comparative Example 8: Nonwoven Fabric #14

[0111] This comparative example provides another recycled flash nonwoven fabric and its preparation method. The steps are basically the same as those in Example 3. The only difference is that in step (1) of this comparative example, the waste high-density polyethylene plastic is directly heated to 160°C, and the resulting nonwoven fabric is denoted as 14#.

[0112] Comparative Example 9: Non-woven fabric #15

[0113] This comparative example provides another recycled flash nonwoven fabric and its preparation method. The steps are basically the same as those in Example 3. The only difference is that in step (2) of this comparative example, the solvent tetrafluorodichloroethane was not preheated, and the resulting nonwoven fabric is denoted as 15#.

[0114] Comparative Example 10: Non-woven fabric #16

[0115] This comparative example provides another recycled flash-evaporated nonwoven fabric and its preparation method, including the following steps:

[0116] Waste high-density polyethylene plastic is cleaned, crushed, heated to 160°C to melt, extruded and granulated, then flash-spun to obtain flash fibers, then laid into a web, and hot-pressed at 105°C to obtain the nonwoven fabric 16#.

[0117] Experimental Example 1

[0118] The following tests were performed on the above nonwoven fabrics 1-16#:

[0119] Test 1, Fracture Strength: Tested in accordance with standard GB / T 3923.1-2013.

[0120] Test 2, Softness: Tested according to standard GB / T 8942-2016.

[0121] The results are shown in Tables 1 and 2 below.

[0122] Table 1

[0123]

[0124]

[0125] Table 1 shows the test results for the strength and softness of the nonwoven fabric. As shown in the table, the tensile strength data indicates that the nonwoven fabric obtained in this application has a tensile strength greater than or equal to 204.7 N / 5 cm and less than or equal to 247.3 N / 5 cm, which is comparable to the strength of virgin nonwoven fabric; it also exhibits high softness, with a longitudinal softness greater than or equal to...

[0126] The tensile strength of the nonwoven fabric obtained in this application is 21.4 mN and less than or equal to 23.3 mN, and the transverse softness is greater than or equal to 23.1 mN and less than or equal to 24.3 mN, while the softness of virgin nonwoven fabric is above 28 mN. This indicates that the nonwoven fabric obtained in this application has a higher softness than virgin nonwoven fabric. In nonwoven fabric #16, waste high-density polyethylene plastic was used directly without treatment to prepare the nonwoven fabric, resulting in a nonwoven fabric with significantly lower strength than other nonwoven fabrics. In contrast, the tensile strength of nonwoven fabrics #1-6 obtained by the method in this application is above 200 N / 5 cm, showing a significant improvement in strength. The tensile strength of nonwoven fabrics #7-11 is significantly lower than that of nonwoven fabric #3, indicating that introducing a certain proportion of vanillic acid and itaconic anhydride into the polyester helps to improve the strength of the nonwoven fabric. In nonwoven fabrics #12-13, shell powder without cyclodextrin modification was added, and the tensile strength of the resulting nonwoven fabric was also lower than that of nonwoven fabric #3, indicating that modifying the shell powder with cyclodextrin before adding it helps to improve the strength of the nonwoven fabric. The results of nonwoven fabrics #14 and #15 show that controlling the heating temperature during the recycling and treatment of waste high-density polyethylene plastic, and preheating the solvent before preparing the spinning solution, can improve the strength of the nonwoven fabric to a certain extent.

[0127] The softness test results show that, compared to non-woven fabric #3, non-woven fabrics #7-#11 have higher softness values, meaning they are less soft than non-woven fabric #3. This indicates that introducing a certain proportion of vanillic acid and itaconic anhydride into the polyester helps compensate for the poor hand feel and softness of non-woven fabrics produced using waste high-density polyethylene plastic. Non-woven fabric #12 has slightly higher softness than non-woven fabric #3, while non-woven fabric #13 has a significantly lower softness than non-woven fabric #3. This suggests that the addition of modified shell powder improves the strength of the non-woven fabric without reducing its softness or affecting its hand feel.

[0128] Experimental Example 2

[0129] Nonwoven fabric 1-16# was placed in an oven at 80℃ for 168 hours, and then its tensile strength retention rate was tested to evaluate its temperature resistance.

[0130] The test results are shown in Table 2 below.

[0131] Table 2

[0132] Nonwoven fabric number Fracture strength retention rate (%) 1# 85.5 2# 87.6 3# 88.7 4# 87.2 5# 86.9 6# 85.7 7# 78.3 8# 76.2 9# 74.7 10# 75.9 11# 74.0 12# 77.4 13# 81.8 14# 85.5 15# 78.6 16# 62.5

[0133] As shown in the table, the nonwoven fabric obtained in this application, after being dried in an oven at 80℃ for 168 hours, still maintained a tensile strength of over 85% of that of the untreated nonwoven fabric, showing almost no change. However, the tensile strength retention rate of nonwoven fabrics 7-11# was significantly lower than that of nonwoven fabric 3#. This indicates that introducing specific chain segments into the polyester in this application and compounding the resulting polyester with recycled polyethylene can improve the high-temperature resistance of the nonwoven fabric. The results for nonwoven fabrics 12 and 13# show that the addition of shell powder after modification treatment can improve the high-temperature resistance of the nonwoven fabric, compensating for the problems caused by the hot-pressing step in the preparation process of recycled nonwoven fabrics.

[0134] Experimental Example 3

[0135] Using a Hunter Lab tester, the yellow index (YI) and b* value of the spinning solution obtained in step (4) of the above examples and comparative examples were determined according to ASTM E313-00. The results are shown in Table 3 below.

[0136] Table 3

[0137]

[0138]

[0139] It is known that the smaller the YI and b* values, the higher the whiteness of the material. As shown in the table, the YI and b* values ​​of the materials in Comparative Examples 6, 7, and 12 are significantly higher than those in Example 3. Therefore, it can be concluded that the whiteness of the final product nonwoven fabric provided by the present invention is higher than that of Comparative Examples 6, 7, and 10. Furthermore, the addition of cyclodextrin-modified shell powder in synergy with calcium stearate can significantly improve the whiteness of the material, compensating for the low whiteness of the recycled polyethylene waste.

[0140] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, this application is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of this application without departing from the scope of this application should be within the protection scope of this application.

Claims

1. A recycled flash-evaporated nonwoven fabric, characterized in that, By weight, it contains the following raw materials: 60 parts or more and 80 parts or less of recycled polyethylene, 10 parts or more and 20 parts or less of polyethylene, 5 parts or more and 15 parts or less of modified polyester, 2 parts or more and 8 parts or less of cyclodextrin-modified shell powder, and 0.02 parts or more and 0.2 parts or less of calcium stearate. The calcium stearate is 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene; the modified polyester is prepared by reacting an aliphatic diol with a diacid, wherein the diacid comprises an aliphatic diacid, vanillic acid, and itaconic anhydride; in the modified polyester, in 1 mole of the diacid, the proportion of the aliphatic diacid is greater than or equal to 70% and less than or equal to 80%, the proportion of vanillic acid is greater than or equal to 2% and less than or equal to 10%, and the proportion of itaconic anhydride is greater than or equal to 10% and less than or equal to 28%; and the modified polyester is specifically prepared by the following method: Under nitrogen protection, the aliphatic diol and the diacid are mixed, a catalyst is added, and the mixture is first reacted at a temperature greater than or equal to 150°C and less than or equal to 160°C for a reaction time greater than or equal to 0.5 h and less than or equal to 1 h. Then, the temperature is increased to greater than or equal to 175°C and less than or equal to 190°C and the reaction continues for a reaction time greater than or equal to 1 h and less than or equal to 3 h. Finally, the mixture is polycondensed at a temperature greater than or equal to 190°C and less than or equal to 210°C for a time greater than or equal to 5 h and less than or equal to 12 h to obtain the modified polyester.

2. The recycled flash nonwoven fabric according to claim 1, characterized in that, The recycled flash nonwoven fabric comprises, by weight, the following raw materials: ≥65 parts and ≤75 parts of recycled polyethylene, ≥12 parts and ≤18 parts of polyethylene, ≥8 parts and ≤12 parts of modified polyester, ≥3 parts and ≤5 parts of cyclodextrin-modified shell powder, and ≥0.05 parts and ≤0.1 parts of calcium stearate.

3. The recycled flash-evaporated nonwoven fabric according to claim 1 or 2, characterized in that, The cyclodextrin-modified shell powder was prepared by the following method: Shell powder was placed in an acidic solution and microwaved. After removal, it was washed and dried to obtain pretreated shell powder. Then, β-cyclodextrin and chloroacetic acid aqueous solution were added to NaOH solution and reacted at a temperature greater than or equal to 50°C and less than or equal to 60°C for a reaction time greater than or equal to 3 hours and less than or equal to 5 hours. After the reaction was completed, the pH was adjusted to greater than or equal to 5 and less than or equal to 7, and excess methanol was added. The mixture was filtered and dried to obtain carboxymethyl β-cyclodextrin. The carboxymethyl β-cyclodextrin was then added to acetone and mixed well. The pretreated shell powder was then added and the reaction was continued at a temperature greater than or equal to 30°C and less than or equal to 60°C for a reaction time greater than or equal to 2 hours and less than or equal to 5 hours. After the reaction was completed, the acetone was removed by vacuum drying to obtain the cyclodextrin-modified shell powder. The amount of carboxymethyl β-cyclodextrin used is greater than or equal to 0.2 parts and less than or equal to 0.4 parts relative to 1 part by weight of the shell powder.

4. The recycled flash nonwoven fabric according to claim 3, characterized in that, The amount of carboxymethyl β-cyclodextrin used is greater than or equal to 0.25 parts and less than or equal to 0.3 parts relative to 1 part by weight of the shell powder.

5. The recycled flash-evaporated nonwoven fabric according to claim 1 or 2, characterized in that, The regenerated flash nonwoven fabric has a tensile strength greater than or equal to 204.7 N / 5 cm and less than or equal to 247.3 N / 5 cm, a longitudinal softness greater than or equal to 21.4 mN and less than or equal to 23.3 mN, and a transverse softness greater than or equal to 23.1 mN and less than or equal to 24.3 mN.

6. The method for preparing the recycled flash-evaporated nonwoven fabric according to any one of claims 1-5, characterized in that, Includes the following steps: First, waste high-density polyethylene is recycled to produce recycled polyethylene masterbatch, which is then melted to obtain recycled polyethylene spinning solution. The solvent is then preheated, and the cyclodextrin-modified shell powder and calcium stearate are added and ultrasonically mixed. Then, the polyethylene and the modified polyester are added and mixed to obtain the first spinning solution. The first spinning solution is mixed with the recycled polyethylene spinning solution, flash-spun, web-laid, and hot-pressed to obtain nonwoven fabric.

7. The preparation method according to claim 6, characterized in that, The steps for recycling waste high-density polyethylene (HDPE) to produce recycled polyethylene masterbatch include: washing and crushing the waste HDPE, soaking it in a soaking solution, washing it with water and drying it, raising the temperature to a level greater than or equal to 140°C and less than or equal to 150°C, and then melt-extruding it to obtain recycled polyethylene masterbatch; wherein... During the heating process, when the temperature increases by 20°C or more but less than or equal to 30°C, the temperature is kept warm for 30 minutes or more but less than or equal to 50 minutes.

8. The preparation method according to claim 6, characterized in that, The preheating temperature is greater than or equal to 80℃ and less than or equal to 100℃, and the preheating time is greater than or equal to 0.5h and less than or equal to 2h.

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