METHOD FOR PREPARING LYOCELL FIBERS FROM SUGARCANE BAGASSE AS RAW MATERIAL

Abstract

A method for preparing Lyocell fibers from sugarcane bagasse is provided, which includes: crushing sugarcane bagasse to 40-80 mesh to obtain sugarcane bagasse powder; putting the sugarcane bagasse powder into a first solution and obtaining pretreated sugarcane bagasse powder; adding the pretreated sugarcane bagasse powder into a second solution and obtaining sugarcane bagasse cellulose; the second solution includes 15-17.5 mol/L glacial acetic acid, 10-15 g/L sodium hypochlorite, and remaining water; adding the sugarcane bagasse cellulose into an NMMO aqueous solution with a mass fraction of 85-88%, stirring and dissolving in a reaction kettle under a vacuum condition at 90-110 C. for 3-5 hours to obtain a transparent spinning solution, where the sugarcane bagasse cellulose has a mass ration of 6-10%; sending the spinning solution into a spinning system for spinning. The process of the present disclosure is simpler, more environmentally friendly, and can reduce costs.

Claims

1. A method for preparing Lyocell fibers from sugarcane bagasse, comprises following steps: step A, crushing sugarcane bagasse to 80 mesh to obtain sugarcane bagasse powder; step B, putting the sugarcane bagasse powder obtained in step A into a first solution, stirring at 70 C. for 3 hours, filtering and washing after reaction is complete, drying filter residue, and then grinding it to 60 mesh to obtain a pre-treated sugarcane bagasse powder; the first solution comprises hydrogen peroxide with a mass fraction of 1%, sodium hydroxide with a mass fraction of 5%, and remaining water; a mass ratio of the first solution to the sugarcane bagasse powder is 20:1; step C, putting the pre-treated sugarcane bagasse powder obtained in step B into a second solution, immersing it in 90 C. for 3 hours, filtering and washing until neutral after reaction is complete, and drying a filter residue in an oven at 60 C. to obtain sugarcane bagasse cellulose; wherein the second solution comprises 17.5 mol/L glacial acetic acid, 10 g/L sodium hypochlorite, and remaining water; a mass ratio of the second solution to the pre-treated sugarcane bagasse powder is 25:1; step D, adding the sugarcane bagasse cellulose obtained in step C into an NMMO aqueous solution with a mass fraction of 85%, stirring and dissolving in a reaction kettle under a vacuum condition at 100 C. for 3 hours to obtain a transparent spinning solution, where a mass fraction of the sugarcane bagasse cellulose in solution is 4/46; step E, sending the spinning solution obtained in step D into a spinning system for spinning; in step A, the sugarcane bagasse is crushed and treated in a water bath at 70 C. for 3 hours, filtered and washed, and dried at 60 C. for 10 hours to obtain the sugarcane bagasse powder; wherein in step D, the NMMO aqueous solution with a mass fraction of 85% is obtained by vacuum distillation of an NMMO aqueous solution with a mass fraction of 50%.

2. The method for preparing Lyocell fibers from sugarcane bagasse according to claim 1, wherein in step B, drying is carried out under a vacuum condition at a drying temperature of 60 C.

3. The method for preparing Lyocell fibers from sugarcane bagasse according to claim 2, wherein in step E, before entering the spinning system, the spinning solution is added to a screw extruder and dissolved at 110 C. for 20 minutes, followed by filtration.

4. The method for preparing Lyocell fibers from sugarcane bagasse according to claim 3, wherein in step E, entering a spinning system, and the sprayed silk thread is vertically stretched in air, entering a coagulation bath, solidifying and forming, and a coagulation bath temperature is 30 C.; wherein the coagulation bath is an NMMO aqueous solution with a mass fraction of 20%, and then undergoes fiber alcohol washing, bleaching, water washing, oiling, and drying.

5. The method for preparing Lyocell fibers from sugarcane bagasse according to claim 4, wherein a mass concentration of ethanol in the alcohol washing is 75%, and an alcohol washing time is 3 hours.

6. The method for preparing Lyocell fibers from sugarcane bagasse according to claim 5, wherein the bleaching uses a strong chlorine solution of 0.1 g/L, a bleaching temperature of 30 C., and a bleaching time of 60 minutes.

7. The method for preparing Lyocell fibers from sugarcane bagasse according to claim 6, wherein in step E, a water washing temperature is 80 C. and a water washing time is 2 hours.

8. The method for preparing Lyocell fibers from sugarcane bagasse according to claim 7, wherein in step E, a drying temperature is 60 C. and a drying time is 24 hours.

Description

DESCRIPTION OF EMBODIMENTS

[0025] In order to better understand the technical solution of the present disclosure, a more detailed explanation will be provided below in combination with the embodiments.

Example 1

[0026] Weighing 100 g of sugarcane bagasse, grinding it to 80 mesh, stirring it in a 70 C. water bath for 3 hours, filtering it, washing it with distilled water, and drying it at 60 C. for 10 hours to obtain clean sugarcane bagasse powder. Weighing 50 g of washed sugarcane bagasse powder and adding it to a beaker, with a mass fraction of 1000 g of a mixed solution of 0.5% (mass ratio) hydrogen peroxide and 5% (mass ratio) sodium hydroxide, stirring magnetically for 3 hours in a 70 C. water bath, used for pretreatment of sugarcane bagasse; after the reaction is complete, filtering and washing until neutral. Placing the filter residue in a vacuum dryer at 60 C. for drying, and then grinding it to 60 mesh for later use. Weighing 10 g of crushed filter residue and immersing it in a mixed solution of 250 g of glacial acetic acid and sodium hypochlorite. The concentration of glacial acetic acid in the mixed solution is 17.5 mol/L, the concentration of sodium hypochlorite is 10 g/L, the treatment temperature is 90 C., and the immersion time is 3 hours. After the reaction is complete, filter and wash until neutral, and drying the filter residue in an oven at 60 C. to obtain sugarcane bagasse cellulose.

[0027] A 50% mass fraction NMMO (i.e. N-Methyl morpholine-N-oxide, the same below) aqueous solution is distilled under reduced pressure to a NMMO aqueous solution with 15% water content. A 50% mass fraction of NMMO aqueous solution is more stable, and a NMMO solution with 15% water content is suitable for dissolving fibrinogen. Weighing 3 g of sugarcane bagasse cellulose and slowly adding it to 47 g of NMMO solution with a water content of 15%. Mixing evenly and stirring in a reaction kettle under a vacuum condition at 90 C. for 3 hours to obtain a uniform and transparent spinning solution with a mass fraction of 6%. Adding the spinning solution to a screw extruder, dissolving it further at 110 C. for 20 minutes, then filtering it and entering the spinning system. Performing spray silk at a spinning speed of 20 m/min, and the sprayed silk is vertically stretched in the air. Entering a coagulation bath, and the coagulation bath is a 15% mass fraction NMMO aqueous solution at a temperature of 20 C. Then, after fiber alcohol washing (ethanol concentration of 75%, alcohol washing time of 3 hours), bleaching (bleaching agent: strong chlorine concentration of 0.1g/L, temperature of 30 C., bleaching for 60 minutes), water washing (80 C. pure water, water washing time of 2 hours), oiling (oil bath solution concentration of 2 g/L, temperature of 70 C., time of 4 hours, oil bath oil model: HY-101, produced by Hangzhou Huaya Chemical Co., Ltd.), and drying (drying temperature of 60 C., 24 hours), the obtained Lyocell fiber has a dry fracture strength of 3.0 cN/dtex, a wet fracture strength of 2.7 cN/dtex, and a fracture elongation of 12%.

Example 2

[0028] Weighing 100 g of sugarcane bagasse, grinding it to 80 mesh, stirring it in a 70 C. water bath for 3 hours, filtering it, washing it with distilled water, and drying it at 60 C. for 10 hours to obtain clean sugarcane bagasse powder. Weighing 50 g of washed sugarcane bagasse powder and adding it to a beaker, with a mass fraction of 1000 g of a mixed solution of 0.8% hydrogen peroxide and 5% sodium hydroxide, stirring magnetically for 3 hours in a 70 C. water bath, used for pretreatment of sugarcane bagasse. After the reaction is complete, filter and wash until neutral. Placing the filter residue in a vacuum dryer at 60 C. for drying, and then grinding it to 60 mesh for later use. Weighing 10 g of crushed filter residue and immersing it in a mixed solution of 250 g ice acetic acid and sodium hypochlorite, with ice acetic acid concentration of 17.5 mol/L and sodium hypochlorite concentration of 10 g/L. The treatment temperature is 90 C. and the immersion time is 3 h. After the reaction is complete, filter and wash until neutral. Drying the filter residue in an oven at 60 C. to obtain sugarcane bagasse cellulose.

[0029] Distillation of a 50% mass fraction NMMO aqueous solution under reduced pressure to a NMMO solution with 15% water content. Weighing 4 g of sugarcane bagasse cellulose and slowly adding it to 46 g of NMMO solution with a water content of 15%. Mixing evenly and stirring in a reaction kettle under vacuum conditions at 100 C. for 3 hours to obtain a uniform and transparent spinning solution with a mass fraction of 8%. Adding the spinning solution to a screw extruder, dissolving it further at 110 C. for 20 minutes, then filtering it and entering the spinning system. Performing spray silk at a spinning speed of 20 m/min, and the sprayed silk is vertically stretched in the air. Entering a coagulation bath, and the coagulation bath is a NMMO aqueous solution with 15% mass fraction at a temperature of 20 C. Then it undergoes fiber alcohol washing (ethanol concentration of 75%, alcohol washing time of 3 hours), bleaching (bleaching agent: strong chlorine concentration of 0.1 g/L, temperature of 30 C., bleaching for 60 minutes), water washing (pure water at 80 C., washing time of 2 hours), oiling (oil bath solution concentration 2 g/L, temperature 70 C., time 4 h, oil bath model: HY-101, produced by Hangzhou Huaya Chemical Co., Ltd.), drying (drying temperature 60 C., 24 h), the obtained Lyocell fiber has a dry fracture strength of 3.3 cN/dtex, a wet fracture strength of 3.1 cN/dtex, and a fracture elongation of 14%.

Example 3

[0030] Weighing 100 g of sugarcane bagasse, grinding it to 80 mesh, stirring it in a 70 C. water bath for 3 hours, filtering it, washing it with distilled water, and drying it at 60 C. for 10 hours to obtain clean sugarcane bagasse powder. Weighing 50 g of washed sugarcane bagasse powder and adding it to a beaker. Adding 1000 g of a mixed solution of 1% hydrogen peroxide and 5% sodium hydroxide to the beaker, and stirring magnetically for 3 hours in a 70 C. water bath for pretreatment of sugarcane bagasse. After the reaction is complete, filtering and washing until neutral. Placing the filter residue in a vacuum dryer at 60 C. for drying, and then grinding it to 60 mesh for later use. Weighing 10 g of crushed filter residue and immersing it in a mixed solution of 250 g ice acetic acid and sodium hypochlorite, with ice acetic acid concentration of 17.5 mol/L and sodium hypochlorite concentration of 10 g/L. The treatment temperature is 90 C. and the immersion time is 3 h. After the reaction is complete, filtering and washing until neutral. Drying the filter residue in an oven at 60 C. to obtain sugarcane bagasse cellulose.

[0031] Distillation of a 50% mass fraction NMMO aqueous solution under reduced pressure to a 15% water content NMMO solution. Weighing 4 g of sugarcane bagasse cellulose and slowly adding it to 46 g of NMMO solution with a water content of 15%. Mixing evenly and stirring in a reaction kettle under a vacuum condition at 100 C. for 3 hours to obtain a uniform and transparent spinning solution with a mass fraction of 8%. Adding the spinning solution to the screw extruder, dissolving it further at 110 C. for 20 minutes, then filtering it and entering the spinning system. Performing spray silk at a spinning speed of 20 m/min, and the sprayed silk is vertically stretched in the air. Entering a coagulation bath, and the coagulation bath is a NMMO aqueous solution with a 20% mass fraction at a temperature of 30 C. Then, after fiber alcohol washing (ethanol concentration of 75%, alcohol washing time of 3 hours), bleaching (bleaching agent: strong chlorine concentration of 0.1 g/L, temperature of 30 C., bleaching for 60 minutes), water washing (pure water at 80 C., water washing time of 2 hours), oiling (oil bath solution concentration of 3 g/L, temperature of 70 C., time of 4 hours, oil bath model: HY-101, produced by Hangzhou Huaya Chemical Co., Ltd.), and drying (drying temperature of 60 C., 24 hours), the obtained Lyocell fiber has a dry fracture strength of 3.7 cN/dtex, a wet fracture strength of 3.4 cN/dtex, and a break elongation of 15%.

[0032] The determination of dry and wet fracture strength and break elongation in this application is carried out using the national standard GB/T14337-2022 Test Method for Tensile Properties of Chemical Fiber Short Fibers.

[0033] The separation and purification of cellulose in sugarcane bagasse are directly related to the purity of cellulose. When the purity of cellulose is less than 90%, it cannot be completely dissolved in the solvent, directly affecting the uniformity of the spinning solution, causing the sprayed silk threads to break or the strength of the prepared Lyocell fibers to be greatly reduced. The extraction process of the present disclosure has a purity of 95% for cellulose, and the polymerization degree of cellulose has a decisive impact on the viscosity and spinnability of the final spinning solution, as well as the physical properties of the finished fibers. Theoretically, the higher the degree of polymerization of pulp, the higher the strength of the finished fibers, but the greater the difficulty of spinning. The degree of polymerization of cellulose in the present disclosure is between 500-650, which is suitable for spinning.

[0034] Of course, the protection scope of the present disclosure is not limited to this embodiment, and anyone who makes similar changes to it can be regarded as not departing from the protection scope of the present disclosure.

[0035] The process of the present disclosure is simpler, more environmentally friendly, and can reduce costs.