阅读说明：本技术 一种以苎麻纤维为原料制备莱赛尔纤维的方法 (Method for preparing lyocell fibers by using ramie fibers as raw materials ) 是由 彭雄义 张延� 陈卓 董雄伟 刘仰硕 王军 于泽浩 梁永红 杨锋 于 2019-11-18 设计创作，主要内容包括：本发明涉及一种以苎麻纤维为原料制备莱赛尔纤维的方法,本发明以苎麻纤维为原料,将苎麻纤维通过生物酶处理、有机溶剂溶解、微波辐射等方法将纤维素分离并提取；然后将纤维素溶于N-甲基吗啉-N-氧化物的水溶液制得纺丝液,最后经过纺丝、水洗、上油、烘干等工序制得莱赛尔纤维。本发明从苎麻纤维提取纤维素,并成功用为莱赛尔纤维的原料；此方法大大地拓展了莱赛尔纤维的原料来源。本发明制备方法简单,原料来源广泛,具有较好的应用与推广前景。(The invention relates to a method for preparing lyocell fiber by using ramie as a raw material, which takes the ramie as the raw material and separates and extracts cellulose from the ramie by methods such as biological enzyme treatment, organic solvent dissolution, microwave radiation and the like; then dissolving cellulose in the aqueous solution of N-methylmorpholine-N-oxide to prepare spinning solution, and finally carrying out the working procedures of spinning, washing, oiling, drying and the like to prepare the lyocell fiber. The invention extracts cellulose from ramie fiber and becomes raw material of lyocell fiber; the method greatly expands the raw material source of the lyocell fiber. The preparation method is simple, the raw materials are wide in source, and the method has good application and popularization prospects.)

1. A method for preparing lyocell fibers by using ramie fibers as raw materials is characterized by comprising the following steps:

(1) and (3) biological enzyme treatment: the degummed ramie fibers are smashed into powder, and biological enzyme treatment is carried out in aqueous solution by adopting a composite biological enzyme preparation, wherein the composite biological enzyme preparation comprises: lignin peroxidase, xylanase and laccase; the enzyme treatment temperature was: and (2) enzyme treatment time is 20-25 ℃, and is as follows: 8-10 hours; after the treatment is finished, filtering, and collecting and drying filter residues;

(2) organic solvent treatment: dissolving the sample treated in the step (1) in a mixed solution of nitric acid and ethanol, heating and refluxing in a water bath with a reflux device at the temperature of 95-100 ℃, and heating and refluxing for 3-6 hours; when the sample turns white, the reflux is finished; then washing with hot water and absolute ethyl alcohol respectively;

the preparation method of the mixed solution of nitric acid and ethanol comprises the following steps: taking 5000mL of absolute ethyl alcohol into a beaker, adding 1000mL of 95-98% concentrated nitric acid into the beaker, wherein the method for adding the concentrated nitric acid comprises the following steps: adding the mixture for multiple times, wherein 50mL of the mixture is added each time, stirring the mixture uniformly for 3-6 minutes after adding, and finishing adding 20 times;

(3) microwave treatment: dissolving the sample treated in the step (2) in 10-15% of sodium hydroxide aqueous solution, and placing the sample in a microwave environment, wherein the microwave power is 110-150W, and the treatment time is 10-15 min; after the treatment is finished, washing the sample to be neutral by using clear water;

(4) preparing spinning solution of the bast fiber and the lyocell fiber: distilling the aqueous solution of NMMO with the mass fraction of 45-55% under reduced pressure to obtain an aqueous solution of NMMO with the mass fraction of 95-99%, uniformly mixing the aqueous solution of NMMO with the fibers treated in the step (3), and stirring and dissolving the mixture in a reaction kettle at 100-110 ℃ for 3-5 hours in vacuum to obtain a spinning solution with the mass fraction of 10-15%;

(5) spinning of the bast-fibre lyocell: adding the spinning solution treated in the step (4) into a screw extruder, further dissolving at 90-130 ℃, then filtering, and entering a spinning system, wherein the length of an air gap is 8-10 cm, the spinning speed is 20-30 m/min, the aperture of a spinneret plate is 50-70 mu m, and the length of a capillary tube with holes is 500-700 mu m; the sprayed silk threads are vertically stretched in the air, enter a coagulating bath, and are coagulated and formed, wherein the concentration of the coagulating bath is 10-15% of the aqueous solution of NMMO, and the temperature of the coagulating bath is 0-10 ℃;

(6) and (3) water washing of the fiber: immersing the fiber treated in the step (5) into hot water at the temperature of 70-85 ℃ for 3-5 minutes at a bath ratio of 1 g: 20-25 mL;

(7) oiling the fibers: immersing the fibers treated in the step (6) into an oil bath solution of 3-4 g/L, wherein the oil bath temperature is 80-85 ℃, the time is 3-5 minutes, and the bath ratio is 1 g: 15-20 mL;

(8) drying the fibers: and (4) drying the fiber treated in the step (7) to obtain the hemp pulp lyocell fiber.

2. The method for preparing lyocell fiber from ramie fiber as claimed in claim 1, wherein the concentration ratio of lignin peroxidase, xylanase and laccase in step (1) is: 1 mg/L: 1-2 mg/L; the ratio of the ramie fiber powder to the composite biological enzyme preparation aqueous solution is as follows: 1 g: 20-30 mL.

3. The method for preparing lyocell fiber from ramie fiber as claimed in claim 1, wherein the ratio of the sample treated in step (1) to the mixed solution of nitric acid and ethanol in step (2) is: 1 g: 10-20 mL.

4. The method for preparing the lyocell fiber from the ramie fiber as the raw material according to claim 1, wherein the ratio of the sample treated in the step (2) to the sodium hydroxide aqueous solution in the step (3) is 1 g: 20-30 mL.

Technical Field

The invention belongs to the technical field of lyocell fibers, and particularly relates to a method for preparing lyocell fibers by using ramie fibers as raw materials.

Background

In order to solve the pollution problem generated in the process of producing regenerated cellulose fibers and simultaneously improve the high-efficiency utilization of the cellulose, the common efforts of numerous experts in the industry are carried out, and a new solvent method regenerated cellulose fiber production technology is successfully applied, namely, N-methylmorpholine-N-oxide (NMMO) is used for dissolving cellulose pulp, and a spinning process and the like are used for preparing regenerated cellulose fibers, namely lyocell fibers. The lyocell fiber has the characteristics of high dry and wet strength, high modulus, low elongation, high hygroscopicity, good antistatic property, softness, easiness in dyeing, easiness in biodegradation and the like, and is called as green fiber with the greatest development prospect in the 21 st century.

The main raw material of the lyocell fiber is cellulose pulp, and the cellulose pulp can be cotton pulp, wood pulp or bamboo pulp. Currently, there are many reports of lyocell fibers, such as: chinese patent application No. 200780053070.1 discloses lyocell fiber for a tire cord and a tire cord comprising the same, which uses α -cellulose as a raw material, and the produced lyocell fiber has superior strength, elongation and modulus to conventional rayon; chinese patent application No. 01817363.2 discloses a method for producing lyocell fibers, which uses cellulose pulp as a main raw material, and the lyocell fibers produced by the method have a high crimp density and a low crimp width and are easily dried.

The relevant research shows that the pulp doped with hemicellulose can also be used as the raw material of lyocell fiber, and the content of the hemicellulose has certain influence on the aggregation state structure of the fiber, the size of fibril aggregation bundles, the dyeing performance of the fiber and the like. Zhang Hui et al adopt different molecular weight cellulose mixed pulp to spin high strength Lyocell fiber, it can be used for carbon fiber precursor and tire cord (the research of cellulose mixed pulp used for preparing high strength Lyocell fiber, synthetic fiber, 2007, 1: 21-24); the study on the applicability of the pulp to the lyocell fiber is discussed in Liqingchun and the like, and the results show that: when the alpha fiber content of the pulp is low and the hemicellulose content is high, the hemicellulose is firstly dissolved in NMMO during the preparation of the spinning solution, so that the viscosity of the NMMO solution is increased, the NMMO solvent is influenced to permeate into the pulp, and the dissolving time is long (Lyocell fibers are suitable for the initial detection of the pulp, Guangxi chemical fiber Commission, 2001, 29 (1): 6). Literature research shows that different cellulose pulp all have certain influence on the quality of the lyocell fibers; at present, the main raw material of the lyocell fiber is wood pulp, but the preparation process of the wood pulp is complex, the price cost is higher, and the finding of a cheap raw material for replacing the wood pulp is an effective method for reducing the cost of the lyocell fiber.

China is one of the most abundant countries of the world with hemp resources, and mainly comprises ramie, sisal, flax, jute and the like, wherein the ramie is widely planted in China due to the advantages of high growth speed, high yield, easiness in survival and the like. The ramie fiber has the advantages that other fibers are difficult to compare: the fabric has the advantages of good functions of moisture absorption, moisture dispersion and ventilation, rapid heat transfer and conduction, coolness, stiffness, no close contact with skin, light weight, strong strength, insect prevention, mildew prevention, less static electricity, difficult pollution of fabric, soft and elegant color tone, roughness and suitability for excretion and secretion of human skin. Furthermore, ramie fibers are rich in cellulose, which has the potential to be used as raw material for lyocell fibers. However, because of their high crystallinity and orientation, flatness and no curl, the ramie fibers have poor softness, poor spinnability and skin-scratchiness, and their advantages are not fully realized due to the problems, thus greatly limiting their application in high-end markets. Therefore, there is a need to develop an efficient method to play an important role in the high-end fiber field.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a method for preparing lyocell fibers by using ramie fibers as raw materials.

A method for preparing lyocell fibers by using ramie fibers as raw materials comprises the following steps:

(1) and (3) biological enzyme treatment: the degummed ramie fibers are smashed into powder, and biological enzyme treatment is carried out in aqueous solution by adopting a composite biological enzyme preparation, wherein the composite biological enzyme preparation comprises: lignin peroxidase, xylanase and laccase; the enzyme treatment temperature was: and (2) enzyme treatment time is 20-25 ℃, and is as follows: 8-10 hours; after the treatment, filtration was carried out, and the residue was collected and dried.

Preferably, the concentration (mg/L) ratio of the lignin peroxidase, xylanase and laccase is: 1: 1-2; the ratio of the ramie fiber powder (g) to the composite biological enzyme preparation aqueous solution (mL) is as follows: at a ratio of 1: 20-30.

(2) Organic solvent treatment: dissolving the sample treated in the step (1) in a mixed solution of nitric acid and ethanol, heating and refluxing in a water bath with a reflux device at the temperature of 95-100 ℃, and heating and refluxing for 3-6 hours; when the sample turns white, the reflux is finished; then washed with hot water and absolute ethanol, respectively.

Preferably, the ratio of the sample (g) treated in step (1) to the mixed solution of nitric acid and ethanol (mL) is: 1: 10-20; the preparation method of the mixed solution of nitric acid and ethanol comprises the following steps: taking 5000mL of absolute ethyl alcohol into a beaker, adding 1000mL of 95-98% concentrated nitric acid into the beaker, wherein the method for adding the concentrated nitric acid comprises the following steps: adding the mixture for multiple times, wherein 50mL of the mixture is added each time, and stirring the mixture uniformly for 3-6 minutes after adding the mixture, wherein the adding is finished for 20 times.

(3) Microwave treatment: dissolving the sample treated in the step (2) in 10-15% of sodium hydroxide aqueous solution, and placing the sample in a microwave environment, wherein the microwave power is 110-150W, and the treatment time is 10-15 min; after the treatment is finished, washing the sample to be neutral by using clear water; preferably, the ratio of the sample (g) treated in the step (2) to the sodium hydroxide aqueous solution (mL) is 1: 20-30.

(4) Preparing spinning solution of the bast fiber and the lyocell fiber: and (3) distilling the aqueous solution of N-methylmorpholine-N-oxide (NMMO) with the mass fraction of 45-55% to a 95-99% aqueous solution of NMMO under reduced pressure, uniformly mixing the aqueous solution with the fibers treated in the step (3), and stirring and dissolving the mixture in a reaction kettle at 100-110 ℃ for 3-5 hours in vacuum to prepare a uniform and transparent spinning solution with the mass fraction of 10-15%.

(5) Spinning of the bast-fibre lyocell: adding the spinning solution treated in the step (4) into a screw extruder, further dissolving at 90-130 ℃, then filtering, and entering a spinning system, wherein the length of an air gap is 8-10 cm, the spinning speed is 20-30 m/min, the aperture of a spinneret plate is 50-70 mu m, and the length of a capillary tube with holes is 500-700 mu m; the sprayed silk threads are vertically stretched in the air, enter a coagulating bath, and are coagulated and formed, wherein the concentration of the coagulating bath is 10-15% of the aqueous solution of NMMO, and the temperature of the coagulating bath is 0-10 ℃.

(6) And (3) water washing of the fiber: and (3) soaking the fiber treated in the step (5) in hot water at the temperature of 70-85 ℃ for 3-5 minutes at a bath ratio of 1 g: 20-25 mL.

(7) Oiling the fibers: and (3) immersing the fibers treated in the step (6) into 3-4 g/L oil bath solution, wherein the oil bath temperature is 80-85 ℃, the time is 3-5 minutes, and the bath ratio is 1 g: 15-20 mL.

(8) Drying the fibers: and (4) drying the fiber treated in the step (7) to obtain the hemp pulp lyocell fiber.

The invention has the following remarkable advantages:

(1) the main raw material of the lyocell fiber usually adopts wood pulp cellulose, and the invention extracts the cellulose from ramie fiber and becomes the raw material of the lyocell fiber; the method greatly expands the raw material source of the lyocell fiber.

(2) The ramie has the advantages of high growth speed, high yield, easy survival and the like, in addition, the ramie contains higher cellulose and is an ideal cellulose supply source, and the method successfully separates and extracts the cellulose by adopting methods such as biological enzyme treatment, organic solvent dissolution, microwave radiation and the like.

(3) The dry breaking strength of the hemp pulp lyocell fiber is 48-49 cN/tex, the dry breaking elongation of the hemp pulp lyocell fiber is 15-16%, and the dry breaking strength is slightly higher than that of the purchased lyocell fiber; the wet breaking strength of the hemp pulp lyocell fiber is between 31 and 33cN/tex and is slightly lower than that of the purchased lyocell fiber, and the wet breaking elongation of the hemp pulp lyocell fiber is between 15 and 16 percent and is slightly higher than that of the purchased lyocell fiber. The cellulose fiber prepared by using ramie as a raw material is a qualified lyocell fiber which can be compared with lyocell fibers on the market.

Drawings

FIG. 1 an electron micrograph of lyocell fibers prepared according to the present invention

Detailed Description

The examples described below illustrate the invention in detail.