Biomass cotton cellulose based on waste cotton textiles and preparation method thereof

Abstract

The invention provides biomass cotton cellulose based on waste cotton textiles and a preparation method thereof, and the method comprises the following steps: crushing the waste cotton textiles, sterilizing, disinfecting, drying, dipping in alkali liquor and cooking, adding a DES eutectic solvent, mixing, pulping the obtained material, bleaching, desanding, concentrating and papermaking to obtain the biomass cotton cellulose. Wherein a metal chlorate catalyst and an auxiliary agent are added during cooking. According to the method, the waste cotton textile is adopted as a raw material, and the cotton cellulose with excellent performance is prepared by performing high-added-value recovery on the waste cotton textile, so that the environmental problem caused by the waste cotton textile can be effectively relieved, and the resource waste is reduced. Meanwhile, the production cost of the cotton cellulose can be reduced, and the problem of insufficient production raw materials of existing biomass cellulose products is solved.

Description

Technical Field

[0001] The invention relates to the technical field of high-value recycling of waste textiles, and in particular to biomass cotton cellulose based on waste cotton textiles and a preparation method thereof. Background Art

[0002] At present, the global resource shortage is becoming more and more serious, the cultivated land area has been greatly reduced, and the cotton planting area is also shrinking. The production of cotton linters is limited by factors such as planting area, growth cycle, and ecological balance. Therefore, a large number of biomass cellulose products need to rely on imports, resulting in high cost prices of cotton cellulose, and it is easily affected by foreign markets, which ultimately affects the downstream biomass cellulose production prices.

[0003] With the shortage of raw material resources and the need for environmental protection, the high-value recycling and reuse of waste cotton textiles has received more and more attention. At present, most waste cotton textiles are recycled by low-value-added methods such as landfill and incineration, which not only causes waste of resources and environmental pollution, but also limits the recycling potential of waste cotton textiles. Waste cotton textiles contain a large amount of natural cotton fibers, which have difficulties such as large molecular weight, high crystallinity, and difficulty in recycling. Therefore, it is particularly important to develop biomass cotton cellulose that can replace cotton pulp for the high-value recycling and reuse of waste cotton textiles. Summary of the invention

[0004] The object of the present invention is to provide a biomass cotton cellulose based on waste cotton textiles, wherein the biomass cotton cellulose has excellent physical and chemical properties.

[0005] Another object of the present invention is to provide a method for preparing biomass cotton cellulose based on waste cotton textiles, which uses waste cotton textiles as raw materials and recycles waste cotton textiles with high added value, thereby effectively alleviating the environmental problems caused by waste cotton textiles, reducing resource waste and lowering the production cost of cotton cellulose.

[0006] The present invention solves the technical problem by adopting the following technical solutions.

[0007] The present invention provides a method for preparing biomass cotton cellulose from waste cotton textiles, comprising the following steps: S1. After the waste cotton textiles are crushed, sterilized, dried, soaked in alkali solution and boiled, a DES low eutectic solvent is added to mix to obtain a material, wherein a metal chloride catalyst and an auxiliary agent are added during the boiling; S2. The material is pulped, bleached, sanded, concentrated and paper-made to obtain biomass cotton cellulose.

[0008] The invention provides biomass cotton cellulose based on waste cotton textiles, which is prepared according to the preparation method.

[0009] The beneficial effects of the biomass cotton cellulose based on waste cotton textiles and the preparation method thereof according to the embodiment of the present invention are: 1. The present invention uses waste cotton textiles as raw materials, and by recycling waste cotton textiles with high added value, it can effectively alleviate the environmental problems caused by waste cotton textiles, reduce resource waste, and further protect the ecological environment. At the same time, it can also reduce the production cost of cotton cellulose and alleviate the problem of insufficient raw materials for the production of existing biomass cellulose products.

[0010] 2. The present invention adds metal salt catalysts and additives to the cooking liquid. The metal salt can promote the cleavage of glycosidic bonds in cellulose during the alkalization process, thereby increasing the degradation rate of cellulose macromolecules, improving cooking efficiency, reducing costs, and facilitating industrial promotion. The addition of aromatic polyoxyethylene ether (cloud point ≥ 80, HLB value ≥ 17) as an additive during the cooking process can effectively reduce the surface tension of the alkali solution, facilitate the penetration of the alkali solution into the crystallization area of ​​cotton cellulose, improve the processing performance of cotton cellulose, thereby reducing the number of gel particles in the regenerated cellulose product and improving the performance indicators of biomass cellulose products.

[0011] 3. The present invention adds an appropriate amount of aminosulfonic acid during the bleaching process, which can effectively improve the bleaching effect. Aminosulfonic acid, as a bleaching aid, can reduce the catalytic effect of metal ions in the bleaching solution, thereby reducing the oxidative degradation of cellulose by heavy metal ions, and avoiding a significant decrease in the physical properties of cotton cellulose. Aminosulfonic acid can have a fixing effect on the reactive groups of cotton cellulose, prevent the peeling reaction of cotton cellulose molecules, inhibit the degradation of cotton cellulose, thereby increasing the content of cotton cellulose and improving the physical strength of cotton cellulose after bleaching.

[0012] 4. The present invention adds a nonionic polyether defoamer during the pulping process, which has excellent defoaming performance, and its long-term anti-foaming property and anti-aging property are particularly outstanding. It effectively reduces the number of bubbles in the glue after the cotton cellulose is dissolved, greatly improves the quality of the glue, and makes the regenerated cellulose product have excellent physical and chemical properties. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0014] The biomass cotton cellulose based on waste cotton textiles and the preparation method thereof according to the embodiments of the present invention are described in detail below.

[0015] The present invention provides a method for preparing biomass cotton cellulose based on waste cotton textiles, comprising the following steps: S1. After the discarded cotton textiles are crushed, sterilized, dried, soaked in alkali solution and boiled, a DES low eutectic solvent is added to mix and a material is obtained, wherein a metal chloride catalyst and an auxiliary agent are added during the boiling. The present invention adds a metal salt catalyst and an auxiliary agent to the cooking liquid. The metal salt can promote the cleavage of the glycosidic bonds in the cellulose during the alkalization process, thereby increasing the degradation rate of cellulose macromolecules, improving the boiling efficiency, reducing costs, and facilitating industrial promotion. Aromatic polyoxyethylene ether (cloud point ≥ 80, HLB value ≥ 17) is added as an auxiliary agent during the cooking process to effectively reduce the surface tension of the alkali solution, facilitate the penetration of the alkali solution into the crystalline area of ​​​​cotton cellulose, and improve the processing performance of cotton cellulose, thereby reducing the number of gel particles in the regenerated cellulose product and improving the performance indicators of biomass cellulose products.

[0016] Furthermore, in a preferred embodiment of the present invention, the average length of the cotton fibers after the waste cotton textiles are crushed is 1-5 mm, the sterilization temperature is 120-140 ° C, the sterilization pressure is 0.2-0.36 MPa, and the sterilization time is 10-30 min.

[0017] Further, in a preferred embodiment of the present invention, the alkali solution used for the alkali solution impregnation is selected from one of sodium hydroxide, potassium hydroxide or calcium hydroxide, the concentration of the alkali solution is 30-60 g / L, the alkali solution temperature is 50-100°C, and the alkali solution impregnation time is 30-90 min. Preferably, the concentration of the alkali solution is 30-50 g / L, the alkali solution temperature is 60-80°C, and the alkali solution impregnation time is 30-60 min.

[0018] Further, in a preferred embodiment of the present invention, the metal chloride catalyst is selected from one of nickel chloride, cobalt chloride, and ferrous chloride, the addition amount of the metal chloride is 10-100 ppm, the auxiliary agent is selected from one of nonionic surfactants LV-3 or HB-3803, the cooking temperature is 155-175°C, and the cooking time is 2-4 h. Preferably, the cooking temperature is 160-175°C, and the cooking time is 2-3.5 h.

[0019] Further, in a preferred embodiment of the present invention, the DES low eutectic solvent includes an HBA component and an HBD component, the HBA component is CoCL2 or ChCL, the HBD component is an acid substance, the acid substance is citric acid or lactic acid, the mass ratio of the HBA component to the HBD component is 1:1~3, the mixing temperature is 50~90°C, and the mixing time is 20~60min. The mass ratio of the DES low eutectic solvent to the waste cotton textiles is 1~3:1. In the present invention, the DES low eutectic solvent is added after cooking and fully mixed with the cooking liquid to remove the lignin component in the cotton cellulose.

[0020] S2. The material is pulped, bleached, sanded, concentrated and paper-made to obtain biomass cotton cellulose.

[0021] Further, in a preferred embodiment of the present invention, the beating time is 20-70 min, the beating temperature is 20-40°C, the beating machine speed is 7.0-8.5 r / s, and the wet weight of the cotton fiber after beating is 15-20 g. Preferably, the beating time is 20-50 min, and the beating machine speed is 7.0-8.0 r / s.

[0022] Further, in a preferred embodiment of the present invention, the bleaching solution used for bleaching comprises a bleaching agent and a bleaching aid, the bleaching agent is selected from one of hydrogen peroxide, chlorine dioxide, and sodium hypochlorite, the bleaching aid is selected from one of aminosulfonic acid and alkyl polyoxyethylene ether, the bleaching temperature is 40-70°C, and the bleaching time is 30-60 min. Preferably, the bleaching temperature is 40-60°C, and the bleaching time is 30-50 min.

[0023] The present invention adds an appropriate amount of aminosulfonic acid during the bleaching process, which can effectively improve the bleaching effect. Aminosulfonic acid, as a bleaching aid, can reduce the catalytic effect of metal ions in the bleaching solution, thereby reducing the oxidative degradation of cellulose by heavy metal ions, and avoiding a significant decrease in the physical properties of cotton cellulose. Aminosulfonic acid can have a fixing effect on the reactive groups of cotton cellulose, prevent the peeling reaction of cotton cellulose molecules, inhibit the degradation of cotton cellulose, thereby increasing the content of cotton cellulose and improving the physical strength of cotton cellulose after bleaching.

[0024] Furthermore, in a preferred embodiment of the present invention, the step of sand removal is: controlling the slurry concentration to 0.5-2%, the desander pressure to 0.28-0.5 MPa for sand removal, and adding a ash removal iron agent to the slurry after sand removal, wherein the amount of the ash removal iron agent is 0.01-0.05% of the mass of the waste cotton textile after drying. Preferably, the slurry concentration is 0.5-1.6%, and the desander pressure is 0.28-0.42 MPa.

[0025] Furthermore, in a preferred embodiment of the present invention, the steps of concentration and papermaking are as follows: the concentration of cotton cellulose in the concentrator is controlled to be 3-5%, and after concentration, a non-ionic defoaming agent is added and the biomass cotton cellulose is papermade by a papermaking machine to obtain the biomass cotton cellulose, wherein the non-ionic defoaming agent is selected from one of HB-TC300 and HB-TC310. Preferably, the concentration of cotton cellulose in the concentrator is controlled to be 3-4.5%. In this embodiment, desalted water is used to papermake the cotton cellulose, and the spraying amount of desalted water is 25-40 m 3 / h. The present invention adds a nonionic polyether defoamer during the pulping process, which has excellent defoaming performance, especially outstanding long-term foam suppression and aging resistance, effectively reduces the number of bubbles in the glue after the cotton cellulose is dissolved, greatly improves the quality of the glue, and makes the regenerated cellulose product have excellent physical and chemical properties.

[0026] The present invention uses waste cotton textiles as raw materials and recycles waste cotton textiles with high added value, thereby effectively alleviating environmental problems caused by waste cotton textiles, reducing resource waste, and further protecting the ecological environment. At the same time, it can also reduce the production cost of cotton cellulose and alleviate the current problem of insufficient raw materials for the production of biomass cellulose products.

[0027] The present invention also provides a biomass cotton cellulose based on waste cotton textiles, which is prepared according to the above preparation method.

[0028] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0029] Example 1 This embodiment provides a biomass cotton cellulose based on waste cotton textiles, which is prepared according to the following steps: (1) Crush the discarded cotton textiles and sterilize them in a high-temperature and high-pressure steam sterilizer at a temperature of 134°C for 12 min. Dry them and set them aside.

[0030] (2) The dried cotton textiles were immersed in a sodium hydroxide solution for 30 min, with a sodium hydroxide concentration of 44 g / L and a temperature of 80°C. After immersion, 20 ppm of cobalt chloride catalyst and 5 mL of polyoxyethylene ether LV-3 were added to a cooking container and kept at 170°C for 2.5 h. Then, DES low eutectic solvent was added to the cooking container and mixed at 70°C for 60 min. The mass ratio of DES low eutectic solvent to waste cotton textiles was 3:1, the HBA component was CoCL2, and the HBD component was citric acid, with HBA:HBD = 1:2 (mass ratio).

[0031] (3) The cotton textiles after cooking were pulped in a pulping machine for 30 min, the pulping temperature was controlled at 30 °C, and the speed of the pulping machine was adjusted to 7.5 r / s. Then, a sodium hypochlorite bleaching solution with a mass fraction of 1% and an aminosulfonic acid concentration of 5 g / L was prepared, and the pulp was bleached in the bleaching solution, wherein the bleaching temperature was 40 °C and the bleaching time was 40 min. Then, the cotton cellulose concentration was controlled to be 1.5% and the desander pressure was 0.36 MPa for desandering. After desandering, a deashing iron agent (NaPO3)6 was added. The amount of the deashing iron agent was 0.05% of the mass of the waste cotton textiles after drying. Finally, the cotton cellulose concentration in the concentrator was controlled to be 3.5%. After concentrating, a non-ionic defoaming agent HB-TC310 was added and the biomass cotton cellulose was obtained after being formed by a papermaking machine.

[0032] Example 2 This embodiment provides a biomass cotton cellulose based on waste cotton textiles, which is prepared according to the following steps: (1) Crush the discarded cotton textiles and sterilize them in a high-temperature and high-pressure steam sterilizer at a temperature of 134°C for 12 min. Dry them and set them aside.

[0033] (2) The dried cotton textiles were immersed in a sodium hydroxide solution for 30 min, with a sodium hydroxide concentration of 44 g / L and a temperature of 80°C; after immersion, 40 ppm of cobalt chloride catalyst and 5 mL of polyoxyethylene ether LV-3 were added to a cooking container and kept at 170°C for 2.5 h; then DES low eutectic solvent was added to the cooking container and mixed at 70°C for 60 min. The mass ratio of DES low eutectic solvent to waste cotton textiles was 3:1, the HBA component was CoCL2; the HBD component was citric acid, and HBA:HBD=1:2 (mass ratio).

[0034] (3) The cotton textiles after cooking were pulped in a pulping machine for 30 min, the pulping temperature was controlled at 30℃, and the speed of the pulping machine was adjusted to 7.5 r / s; then, a 1% sodium hypochlorite bleaching solution and an aminosulfonic acid concentration of 5 g / L were prepared, and the pulp was bleached in the bleaching solution, wherein the bleaching temperature was 40℃ and the bleaching time was 40 min. Then, the cotton cellulose concentration was controlled to be 1.5% and the desander pressure was 0.36 MPa for desandering. After desandering, a deashing iron agent (NaPO3)6 was added. The amount of the deashing iron agent was 0.05% of the mass of the waste cotton textiles after drying. Finally, the cotton cellulose concentration in the concentrator was controlled to be 3.5%. After concentrating, a non-ionic defoaming agent HB-TC310 was added and the biomass cotton cellulose was obtained after being formed by a papermaking machine.

[0035] Example 3 This embodiment provides a biomass cotton cellulose based on waste cotton textiles, which is prepared according to the following steps: (1) Crush the discarded cotton textiles and sterilize them in a high-temperature and high-pressure steam sterilizer at a temperature of 134°C for 12 min. Dry them and set them aside.

[0036] (2) The dried cotton textiles were immersed in a sodium hydroxide solution for 30 min, with a sodium hydroxide concentration of 44 g / L and a temperature of 80°C; after immersion, 60 ppm of cobalt chloride catalyst and 5 mL of polyoxyethylene ether LV-3 were added to the cooking container and kept at 170°C for 2.5 h; then DES low eutectic solvent was added to the cooking container and mixed at 70°C for 60 min. The mass ratio of DES low eutectic solvent to waste cotton textiles was 3:1, the HBA component was CoCL2; the HBD component was citric acid, and HBA:HBD=1:2 (mass ratio).

[0037] (3) The cotton textiles after cooking were pulped in a pulping machine for 30 min, the pulping temperature was controlled at 30℃, and the speed of the pulping machine was adjusted to 7.5 r / s; then, a 1% sodium hypochlorite bleaching solution and an aminosulfonic acid concentration of 5 g / L were prepared, and the pulp was bleached in the bleaching solution at a bleaching temperature of 40℃ and a bleaching time of 40 min. Then, the cotton cellulose concentration was controlled to be 1.5% and the desander pressure was 0.36 MPa for desandering. After desandering, a deashing iron agent (NaPO3)6 was added. The amount of the deashing iron agent was 0.05% of the mass of the waste cotton textiles after drying. Finally, the cotton cellulose concentration in the concentrator was controlled to be 3.5%. After concentrating, a non-ionic defoaming agent HB-TC310 was added and the biomass cotton cellulose was obtained after being formed by a papermaking machine.

[0038] Example 4 This embodiment provides a biomass cotton cellulose based on waste cotton textiles, which is prepared according to the following steps: (1) Crush the discarded cotton textiles and sterilize them in a high-temperature and high-pressure steam sterilizer at a temperature of 134°C for 12 min. Dry them and set them aside.

[0039] (2) The dried cotton textiles were immersed in a sodium hydroxide solution for 30 min, with a sodium hydroxide concentration of 44 g / L and a temperature of 80°C; after immersion, 80 ppm of cobalt chloride catalyst and 5 mL of polyoxyethylene ether LV-3 were added to a cooking container and kept at 170°C for 2.5 h; then DES low eutectic solvent was added to the cooking container and mixed at 70°C for 60 min. The mass ratio of DES low eutectic solvent to waste cotton textiles was 3:1, the HBA component was CoCL2, and the HBD component was citric acid, with HBA:HBD = 1:2 (mass ratio).

[0040] (3) The cotton textiles after cooking were pulped in a pulping machine for 30 min, the pulping temperature was controlled at 30℃, and the speed of the pulping machine was adjusted to 7.5 r / s; then, a 1% sodium hypochlorite bleaching solution and an aminosulfonic acid concentration of 5 g / L were prepared, and the pulp was bleached in the bleaching solution at a bleaching temperature of 40℃ and a bleaching time of 40 min. Then, the cotton cellulose concentration was controlled to be 1.5% and the desander pressure was 0.36 MPa for desandering. After desandering, a deashing iron agent (NaPO3)6 was added. The amount of the deashing iron agent was 0.05% of the mass of the waste cotton textiles after drying. Finally, the cotton cellulose concentration in the concentrator was controlled to be 3.5%. After concentrating, a non-ionic defoaming agent HB-TC310 was added and the biomass cotton cellulose was obtained after being formed by a papermaking machine.

[0041] Example 5 This embodiment provides a biomass cotton cellulose based on waste cotton textiles, which is prepared according to the following steps: (1) Crush the discarded cotton textiles and sterilize them in a high-temperature and high-pressure steam sterilizer at a temperature of 134°C for 12 min. Dry them and set them aside.

[0042] (2) The dried cotton textiles were immersed in a sodium hydroxide solution for 30 min, with a sodium hydroxide concentration of 44 g / L and a temperature of 80°C; after immersion, 100 ppm of cobalt chloride catalyst and 5 mL of polyoxyethylene ether LV-3 were added to the cooking container and kept at 170°C for 2.5 h; then DES low eutectic solvent was added to the cooking container and mixed at 70°C for 60 min. The mass ratio of DES low eutectic solvent to waste cotton textiles was 3:1, the HBA component was CoCL2, and the HBD component was citric acid, with HBA:HBD=1:2 (mass ratio).

[0043] (3) The cotton textiles after cooking were pulped in a pulping machine for 30 min, the pulping temperature was controlled at 30℃, and the speed of the pulping machine was adjusted to 7.5 r / s; then, a 1% sodium hypochlorite bleaching solution and an aminosulfonic acid concentration of 5 g / L were prepared, and the pulp was bleached in the bleaching solution at a bleaching temperature of 40℃ and a bleaching time of 40 min. Then, the cotton cellulose concentration was controlled to be 1.5% and the desander pressure was 0.36 MPa for desandering. After desandering, a deashing iron agent (NaPO3)6 was added. The amount of the deashing iron agent was 0.05% of the mass of the waste cotton textiles after drying. Finally, the cotton cellulose concentration in the concentrator was controlled to be 3.5%. After concentrating, a non-ionic defoaming agent HB-TC310 was added and the biomass cotton cellulose was obtained after being formed by a papermaking machine.

[0044] Comparative Example 1 This comparative example provides a finished cotton cellulose, which is prepared according to the following steps: (1) Crush the discarded cotton textiles and sterilize them in a high-temperature and high-pressure steam sterilizer at a temperature of 134°C for 12 min. Dry them and set them aside for later use.

[0045] (2) The dried cotton textiles were immersed in a sodium hydroxide solution for 30 min with a sodium hydroxide concentration of 44 g / L and a temperature of 80°C. After immersion, 5 mL of polyoxyethylene ether LV-3 was added into a cooking container and kept at 170°C for 2.5 h. Then, DES low eutectic solvent was added into the cooking container and mixed at 70°C for 60 min. The mass ratio of DES low eutectic solvent to waste cotton textiles was 3:1, the HBA component was CoCL2, and the HBD component was citric acid, with HBA:HBD=1:2 (mass ratio).

[0046] (3) The cotton textiles after cooking were pulped in a pulping machine for 30 min, the pulping temperature was controlled at 30℃, and the speed of the pulping machine was adjusted to 7.5 r / s; then, a 1% sodium hypochlorite bleaching solution and an aminosulfonic acid concentration of 5 g / L were prepared, and the pulp was bleached in the bleaching solution at a bleaching temperature of 40℃ and a bleaching time of 40 min. Then, the cotton cellulose concentration was controlled to be 1.5% and the desander pressure was 0.36 MPa for desandering. After desandering, a deashing iron agent (NaPO3)6 was added. The amount of the deashing iron agent was 0.05% of the mass of the waste cotton textiles after drying. Finally, the cotton cellulose concentration in the concentrator was controlled to be 3.5%. After concentrating, a non-ionic defoaming agent HB-TC310 was added. After the papermaking machine was used for forming, the finished cotton cellulose was obtained.

[0047] Comparative Example 2 This comparative example provides a finished cotton cellulose, which is prepared according to the following steps: (1) Crush the discarded cotton textiles and sterilize them in a high-temperature and high-pressure steam sterilizer at a temperature of 134°C for 12 min. Dry them and set them aside for later use.

[0048] (2) The dried cotton textiles were immersed in a sodium hydroxide solution with a concentration of 44 g / L and a temperature of 80°C for 30 min; after immersion, the textiles were placed in a cooking container and kept at 170°C for 2.5 h; then, DES low eutectic solvent was added to the cooking container and mixed at 70°C for 60 min, wherein the mass ratio of DES low eutectic solvent to waste cotton textiles was 3:1, the HBA component was CoCL2, and the HBD component was citric acid, with HBA:HBD = 1:2 (mass ratio).

[0049] (3) The cotton textiles after cooking were pulped in a pulping machine for 30 min, the pulping temperature was controlled at 30℃, and the speed of the pulping machine was adjusted to 7.5 r / s; then, a 1% sodium hypochlorite bleaching solution and an aminosulfonic acid concentration of 5 g / L were prepared, and the pulp was bleached in the bleaching solution at a bleaching temperature of 40℃ and a bleaching time of 40 min. Then, the cotton cellulose concentration was controlled to be 1.5% and the desander pressure was 0.36 MPa for desandering. After desandering, a deashing iron agent (NaPO3)6 was added. The amount of the deashing iron agent was 0.05% of the mass of the waste cotton textiles after drying. Finally, the cotton cellulose concentration in the concentrator was controlled to be 3.5%. After concentrating, a non-ionic defoaming agent HB-TC310 was added. After the papermaking machine was used for forming, the finished cotton cellulose was obtained.

[0050] Test Example 1 In this test example, the performance of the biomass cotton cellulose of Examples 1 to 5 and the finished cotton cellulose of Comparative Examples 1 to 2 was tested (regenerated cellulose fiber pulp, cotton pulp and wood pulp, FZ / T 51001-2022), and the test results are shown in Table 1.

[0051] Table 1 Performance test of recycled cotton cellulose

[0052] As can be seen from Table 1, the addition of catalysts and additives during the cooking process has a significant impact on the copper-ammonia viscosity, cellulose content, and reaction performance of the finished cotton cellulose. The catalyst can promote the cleavage of glycosidic bonds in cotton cellulose during the cooking process, thereby promoting the degradation of cotton cellulose. Polyoxyethylene ether additives can effectively reduce the surface tension of alkali solution, which is conducive to the penetration of alkali solution into the crystallization area of ​​cellulose molecules, thereby improving the cooking efficiency. Therefore, the addition of catalysts and additives to the cooking system at the same time can utilize their synergistic effect to enhance the penetration and evacuation of cotton fibers, accelerate the oxidation degradation of fibers, and reduce their degree of polymerization.

[0053] The embodiments described above are part of the embodiments of the present invention, rather than all of the embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

Claims

1. A method for preparing biomass cotton cellulose based on waste cotton textiles, characterized in that: The following steps are involved: S1. After the waste cotton textiles are crushed, sterilized, dried, soaked in alkali solution and boiled, a DES low eutectic solvent is added to mix to obtain a material, wherein a metal chloride catalyst and an auxiliary agent are added during the boiling; S2. The material is pulped, bleached, sanded, concentrated and paper-made to obtain biomass cotton cellulose.

2. The preparation method according to claim 1, characterized in that: In step S1, the average length of the cotton fibers after the waste cotton textiles are crushed is 1-5 mm, the sterilization temperature is 120-140° C., the sterilization pressure is 0.2-0.36 MPa, and the sterilization time is 10-30 min.

3. The preparation method according to claim 1, characterized in that: In step S1, the alkali solution used for the alkali solution impregnation is selected from one of sodium hydroxide, potassium hydroxide or calcium hydroxide, the concentration of the alkali solution is 30-60 g / L, the alkali solution temperature is 50-100° C., and the alkali solution impregnation time is 30-90 min.

4. The preparation method according to claim 1, characterized in that: In step S1, the metal chloride catalyst is selected from one of nickel chloride, cobalt chloride, and ferrous chloride, the addition amount of the metal chloride is 10-100 ppm, the auxiliary agent is selected from one of the non-ionic surfactants LV-3 or HB-3803, the cooking temperature is 155-175° C., and the cooking time is 2-4 h.

5. The preparation method according to claim 1, characterized in that: In step S1, the DES low eutectic solvent includes an HBA component and an HBD component, the HBA component is CoCL2 or ChCL, the HBD component is an acid substance, the acid substance is citric acid or lactic acid, the mass ratio of the HBA component to the HBD component is 1:1~3, the mixing temperature is 50~90°C, and the mixing time is 20~60 min.

6. The preparation method according to claim 1, characterized in that: In step S2, the beating time is 20-70 min, the beating temperature is 20-40° C., and the beater speed is 7.0-8.5 r / s.

7. The preparation method according to claim 1, characterized in that: In step S2, the bleaching solution used for bleaching includes a bleaching agent and a bleaching aid, the bleaching agent is selected from one of hydrogen peroxide, chlorine dioxide, and sodium hypochlorite, the bleaching aid is selected from one of aminosulfonic acid and alkyl polyoxyethylene ether, the bleaching temperature is 40-70°C, and the bleaching time is 30-60min.

8. The preparation method according to claim 1, characterized in that: In step S2, the sand removal step is: controlling the slurry concentration to 0.5~2%, the desander pressure to 0.28~0.5 MPa for sand removal, and adding a dust removal iron agent to the slurry after sand removal, wherein the amount of the dust removal iron agent is 0.01~0.05% of the mass of the waste cotton textile after drying.

9. The preparation method according to claim 1, characterized in that: In step S2, the concentration and papermaking steps are as follows: controlling the concentration of cotton cellulose in the concentrator to 3-5%, adding a non-ionic defoaming agent after concentration, and forming the biomass cotton cellulose through papermaking by a papermaking machine, wherein the non-ionic defoaming agent is selected from one of HB-TC300 and HB-TC310.

10. A biomass cotton cellulose based on waste cotton textiles, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 9.

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