CN113550019A

CN113550019A - Preparation method of colored regenerated cellulose conductive filament based on waste textile

Info

Publication number: CN113550019A
Application number: CN202110908027.0A
Authority: CN
Inventors: 樊威; 刘红霞; 苗亚萍; 窦皓; 张聪; 荣凯; 张瑶
Original assignee: Xian Polytechnic University
Current assignee: Xian Polytechnic University
Priority date: 2021-08-09
Filing date: 2021-08-09
Publication date: 2021-10-26
Anticipated expiration: 2041-08-09
Also published as: CN113550019B

Abstract

The invention discloses a preparation method of a colored regenerated cellulose conductive filament based on waste textiles, which comprises the following steps: classifying and recycling the waste textiles, and opening the waste textiles into waste fibers; treating waste fibers with dilute inorganic acid, and dissolving the waste fibers in ionic liquid to obtain regenerated cellulose solution; dispersing indium tin oxide in dimethyl sulfoxide to obtain indium tin oxide dispersion liquid; mixing the regenerated cellulose solution and the indium tin oxide dispersion liquid, then carrying out ultrasonic treatment, and stirring to obtain a regenerated cellulose spinning solution; and then carrying out wet spinning, and leaching the residual ionic liquid to obtain the regenerated cellulose conductive filament with the corresponding color. The method is simple to operate, parameters are easy to control, and the colored regenerated cellulose conductive filament prepared by recovering, pretreating, dissolving and preparing the conductive spinning solution for the colored waste textiles and wet spinning has good micro-morphology and excellent mechanical property, color fastness and conductivity.

Description

Preparation method of colored regenerated cellulose conductive filament based on waste textile

Technical Field

The invention belongs to the field of recycling of waste textiles, and particularly relates to a preparation method of a colored regenerated cellulose conductive filament based on waste textiles.

Background

The total amount of fiber processing in China is about 5000 ten thousand tons every year, and waste textiles of more than 2000 ten thousand tons are produced every year. 300 ten thousand tons of waste cotton textiles account for 50 percent of the waste natural fiber textiles. In recent years, with the improvement of living standard, the consumption demand of people for pure cotton textiles is continuously increased, and the quantity of waste cotton textiles is continuously increased. However, 75-80% of waste cotton is mainly treated by incineration and landfill, which generates malodorous gases, polluting air, surface water and ground water. In addition, the textile contains heavy metal ions, dyes and penetrants, which cause environmental and public health problems if the textile is not properly treated, thereby not only wasting precious resources, but also causing serious pollution to the environment. Therefore, the recycling of waste textiles is very important. The existing method for recycling waste textiles mainly comprises mechanical recycling, chemical recycling and heat energy recycling. The performance and economic value of the product obtained by mechanical recovery are low, and the potential recovery value of cotton is lost by heat energy recovery. Therefore, the recycling of waste textiles becomes a problem to be solved at present.

Currently, functional fibers composed of polymers and electrical conductors are of interest. Cellulose is the most abundant natural polymer in nature, has biocompatibility, biodegradability and better thermal stability and chemical stability, and can be ingeniously combined with metal powder, conductive polymers and the like to prepare the conductive fibers. The imidazole ionic liquid is a good solvent for cellulose, and is a green solvent for dissolving cellulose, wherein anions in the imidazole ionic liquid are mainly utilized to effectively destroy hydrogen bonds among cellulose molecules so that the cellulose is dissolved without degradation, and the solvent is difficult to volatilize and easy to recover. However, the cellulose solution dissolved by the ionic liquid has high viscosity and is not easy to spin, and the application of the waste textile in preparing the fiber is influenced. Meanwhile, the literature, "influence of dyeing and washing on the structure and performance of the conductive fiber" discloses that dyeing can damage the surface structure of the conductive fiber, so as to reduce the conductivity of the fiber, thereby influencing the application of waste textiles in the preparation of the conductive fiber.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to solve the technical problem of providing a preparation method of a colored regenerated cellulose conductive filament based on waste textiles.

The technical scheme for solving the technical problem is to provide a preparation method of colored regenerated cellulose conductive filaments based on waste textiles, which is characterized by comprising the following steps:

1) classifying and recycling the waste textiles, and opening the waste textiles into waste fibers;

2) treating the waste fibers obtained in the step 1) with dilute inorganic acid to reduce the polymerization degree of the waste fibers, washing the waste fibers to be neutral with deionized water, and drying;

3) dissolving the fiber obtained in the step 2) by using ionic liquid to obtain regenerated cellulose solution;

4) dispersing indium tin oxide in dimethyl sulfoxide to obtain indium tin oxide dispersion liquid;

5) mixing the regenerated cellulose solution obtained in the step 3) with the indium tin oxide dispersion liquid obtained in the step 4), then carrying out ultrasonic treatment, and stirring to obtain a regenerated cellulose spinning solution;

6) carrying out wet spinning on the regenerated cellulose spinning solution obtained in the step 5) to obtain a nascent regenerated cellulose conductive filament;

7) soaking the nascent regenerated cellulose conductive filament obtained in the step 6) in deionized water to remove residual ionic liquid, so as to obtain the regenerated cellulose conductive filament with corresponding color.

Compared with the prior art, the invention has the beneficial effects that:

(1) the method is simple to operate, parameters are easy to control, and the colored regenerated cellulose conductive filament prepared by recovering, pretreating, dissolving and preparing the conductive spinning solution for the colored waste textiles and wet spinning has good micro-morphology and excellent mechanical property, color fastness and conductivity.

(2) The method keeps the original color of the waste textiles, the weak acid environment pretreatment is used for reducing the polymerization degree of cellulose, the ionic liquid cellulose dissolving process mainly acts on cellulose molecules, and the two processes can not damage and destroy the dye, so that the dye stably exists on the fiber, the bleaching of the waste textiles and the secondary dyeing of regenerated cellulose conductive filaments are avoided, the pollution is reduced, the cost and the production time are saved, the green recycling cycle is realized, and the damage of the surface structure of the conductive fiber caused by the dyeing process is avoided, and the conductivity of the conductive fiber is further influenced.

(3) The method has no requirement on the strength of the waste textiles, and the waste textiles with extremely low strength can still be used after long-term use. The method is characterized in that the method firstly carries out the pretreatment of acid treatment and crushing on the waste textiles, but the textiles with long service time and low strength are easy to pretreat, thereby avoiding the defect of limited application of regenerated yarns caused by short fiber and low strength in mechanical recovery and realizing 100 percent recycling of the waste cotton textiles.

(4) According to the method, transparent conductive indium tin oxide and regenerated cellulose are mixed for wet spinning, a conductive material is embedded into fibers, so that the conductive performance is stable and cannot fall off, the prepared regenerated cellulose conductive filament has the functions of static electricity prevention, radiation prevention and the like, the original color of waste textiles cannot be influenced by the indium tin oxide, and the recovery and high-quality utilization of the waste textiles are realized.

(5) The method explores the possibility of mixing different colored fiber powders together to create a new color. The mixture of yellow and blue fiber powders produced green fibers with a uniform color distribution. Similarly, the ability to create new colors using colored cotton waste blends can increase process flexibility, further reducing the need for conventional coloring processes, as a blend of blue and red fiber powders produces purple fibers.

(6) The color regenerated cellulose conductive filament prepared by the method has the breaking strength of 100-400 Mpa, the breaking elongation of 5-17% and the color fastness of 4-5 grade; the conductivity is 0.1-200S/m, the textile woven by the conductive filament has excellent mechanical property, antistatic property, radiation protection and other properties, the protection efficiency of the tube voltage of 120kV (energy of 100keV) X-ray is 20-80%, and the conductive filament can be used in the fields of intelligent wear, radiation protection clothing preparation and the like.

Drawings

FIG. 1 is an SEM image of the surface of a regenerated cellulose conductive filament prepared in example 1 of the present invention;

FIG. 2 is an enlarged partial SEM of FIG. 1 in accordance with the present invention;

FIG. 3 is an SEM image of a cross-section of a regenerated cellulose conductive filament prepared according to example 1 of the present invention;

FIG. 4 is an enlarged partial SEM of FIG. 3 according to the present invention;

FIG. 5 is an XRD pattern of the feedstock and the prepared regenerated cellulose conductive filaments of example 3 and comparative example 3 of the present invention;

FIG. 6 is a schematic view of a wet spinning apparatus of the present invention.

Detailed Description

Specific examples of the present invention are given below. The specific examples are only intended to illustrate the invention in further detail and do not limit the scope of protection of the claims of the present application.

The invention provides a preparation method (method for short) of colored regenerated cellulose conductive filaments based on waste textiles, which is characterized by comprising the following steps:

1) classifying and recycling the waste textiles according to colors, keeping the original colors of the waste textiles, and opening the waste textiles into waste fibers through a cloth opener;

preferably, in the step 1), the waste textiles are textiles with different colors and different worn degrees, which are made of fibers with cellulose as a main component substance, and comprise pure cotton textiles, pure hemp textiles, viscose textiles and the like.

2) Treating the waste fibers obtained in the step 1) with dilute inorganic acid to reduce the polymerization degree of the waste fibers, facilitating the dissolution, washing with deionized water to be neutral, and drying;

preferably, in step 2), the inorganic acid is sulfuric acid, nitric acid or hydrochloric acid;

preferably, in step 2), the treatment conditions are: treating in a water bath environment with the temperature of 50-90 ℃ (preferably 75 ℃) for 0.5-3 h in inorganic acid with the concentration of 0.1-1 wt% (preferably 0.5 wt%).

preferably, in step 3), the dissolution conditions are: dissolving the cellulose in an oil bath environment at 70-100 ℃ (preferably 90 ℃) for 1-6 h to obtain a regenerated cellulose solution with the concentration of 3-20 wt% (preferably 3-12 wt%).

Preferably, in step 3), the ionic liquid is 1-butyl-3-methylimidazolium chloride.

preferably, in the step 4), the concentration of the indium tin oxide dispersion is 0.5 to 3 wt% (preferably 0.5 to 2 wt%); during dispersion, an ultrasonic mode and a stirring interval alternate mode are adopted, stirring is carried out for 10-40 min after every 10-40 min of ultrasonic (preferably stirring is carried out for 0.5h after every 0.5h of ultrasonic), the total ultrasonic time is 1-3 h (preferably 2h), and an ultrasonic cleaning machine is adopted for ultrasonic.

5) Mixing the regenerated cellulose solution obtained in the step 3) with the indium tin oxide dispersion liquid obtained in the step 4), then ultrasonically oscillating for 0.2-2 h (preferably 1-2 h) under the ultrasonic wave with the power of 30-8000W (preferably 180W) and the frequency of 20-120 kHz (preferably 40kHz), and then stirring for 1-2 h at the normal temperature at the speed of 0-1000 r/min (preferably 300r/min) by using a magnetic stirrer to obtain a regenerated cellulose spinning solution;

preferably, in the step 5), the mass ratio of the indium tin oxide dispersion liquid to the regenerated cellulose solution is 1-5: 1 (preferably 1-3: 1).

preferably, in the step 6), the coagulation bath for wet spinning is deionized water at 25-70 ℃, and the spinning conditions are as follows: the specification of the injector is 20-100 ml, the pump flow rate, namely the advancing speed of the spinning solution, is 40-100 ml/h, the diameter of a spinning needle head is 0.45-1.2 mm, the speed of a roller I is 20-50 mm/s, and the speed ratio of a roller II to a roller I is 1-3: 1; the speed of the winding roller is the same as that of the second roller.

7) Soaking the nascent regenerated cellulose conductive filament obtained in the step 6) in deionized water for at least 2h for completely leaching out residual ionic liquid, and then drying to obtain the regenerated cellulose conductive filament with corresponding color.

Preferably, a step of: freezing the fiber obtained in the step 2) by liquid nitrogen, and immediately putting the fiber into a Raymond mill to mill the fiber into powder.

In the examples below, the electrical resistance of the filaments was measured with a multimeter and the conductivity was calculated. The test method of the strength and the elongation at break is a single fiber strength machine tensile test, a YG001D electronic single fiber strength machine, the gauge length is 20mm, and the tensile speed is 10 mm/min.

Example 1

1) Recycling red waste pure cotton textiles, and opening waste cotton cloth by using a fine shuttle multifunctional opening machine to obtain waste cotton fibers;

2) adding 2g of waste cotton fibers into 200ml of 0.5 wt% dilute sulfuric acid, heating to 75 ℃ in a water bath kettle, keeping for 2h, washing with deionized water to be neutral, and drying in an oven at 50 ℃ for later use;

3) freezing the fiber obtained in the step 2) by liquid nitrogen, and immediately putting the fiber into a Raymond mill to be ground into powder;

4) weighing 3g of 1-butyl-3-methylimidazolium chloride in a sealed bottle, and putting the sealed bottle in an oil bath pan at 90 ℃ until the sealed bottle is transparent; weighing 0.2g of the powder obtained in the step 3), placing the powder in a sealed bottle, and completely dissolving the fiber in an oil bath kettle at 90 ℃ to obtain a regenerated cellulose solution;

5) 0.1g of indium tin oxide was dispersed in 6g of dimethyl sulfoxide to obtain an indium tin oxide dispersion; during dispersion, stirring for 0.5h after every 0.5h of ultrasonic treatment;

6) mixing the regenerated cellulose solution obtained in the step 4) with the indium tin oxide dispersion liquid obtained in the step 5), then carrying out ultrasonic treatment for 1h under ultrasonic waves with the power of 180W and the frequency of 40kHz, and then stirring for 1h at normal temperature at the speed of 300r/min by using a magnetic stirrer to obtain a regenerated cellulose spinning solution;

7) defoaming the regenerated cellulose spinning solution obtained in the step 6), placing the regenerated cellulose spinning solution into a 20ml medical injector, then connecting a spinning needle, and carrying out wet spinning in a wet spinning device, wherein the spinning solution advancing speed is 70ml/h, the roller I speed is 20mm/s, the speed ratio of the roller II to the roller I is 1.5:1, and the receiving mode is roller receiving to obtain the nascent regenerated cellulose conductive filament;

8) soaking the nascent regenerated cellulose conductive filament obtained in the step 7) in deionized water for 2h, and drying at 50 ℃ to obtain the red regenerated cellulose conductive filament.

As can be seen from fig. 1 and fig. 2, the red regenerated cellulose conductive filament prepared in example 1 is uniform, and the surface of the red regenerated cellulose conductive filament is in a groove shape along the longitudinal direction, which is a typical structural feature of a fiber prepared by wet spinning, and illustrates that the regenerated cellulose conductive filament prepared by the present invention is well formed.

As can be seen from FIGS. 3 and 4, the regenerated cellulose conductive filament has a circular cross section and a compact structure, and has no obvious defect cavities inside, which indicates that the preparation process of the invention is superior, and the prepared regenerated cellulose conductive filament has a better structure.

Comparative example 1

Comparative example 1 differs from example 1 in that: the method is characterized in that a conductive material indium tin oxide is not added into a regenerated cellulose spinning solution, and specifically comprises the following steps:

2) weighing 2g of waste cotton fibers, adding the waste cotton fibers into 200ml of dilute sulfuric acid with the concentration of 0.5 wt%, heating the waste cotton fibers to 75 ℃ in a water bath, keeping the temperature for 2h, washing the waste cotton fibers to be neutral by deionized water, and drying the waste cotton fibers in an oven at 50 ℃ for later use;

5) putting the regenerated cellulose solution obtained in the step 4) into a 20ml medical injector, then connecting a spinning needle, and carrying out wet spinning in a wet spinning device, wherein the advancing speed of a spinning solution is 70ml/h, the speed of a roller I is 20mm/s, the speed ratio of a roller II to the roller I is 1.5:1, and the receiving mode is roller receiving to obtain a nascent regenerated cellulose filament;

6) soaking the regenerated cellulose filaments obtained in the step 5) in deionized water for 2h, and drying at 50 ℃ to obtain red regenerated cellulose filaments.

TABLE 1

Examples of the invention	strength/MPa	Elongation at break/%	Conductivity S/m
				Example 1	323.58	11.95	0.13
Comparison ofExample 1	330.86	11.58	——

As can be seen from table 1, in example 1, compared with comparative example 1, the addition of indium tin oxide does not reduce the mechanical properties of the cellulose filament, so that the cellulose filament has good conductivity while maintaining excellent mechanical properties.

Example 2

1) Recycling blue waste pure cotton textiles, and opening the waste cotton cloth by using a fine shuttle multifunctional opening machine to obtain waste cotton fibers;

5) 0.2g of indium tin oxide was dispersed in 6g of dimethyl sulfoxide to obtain an indium tin oxide dispersion; during dispersion, stirring for 0.5h after every 0.5h of ultrasonic treatment;

8) soaking the nascent regenerated cellulose conductive filament obtained in the step 7) in deionized water for 2h, and drying at 50 ℃ to obtain the blue regenerated cellulose conductive filament.

Comparative example 2

Comparative example 2 differs from example 2 in that: the raw materials adopt pure white waste pure cotton textiles, and the final cellulose filament needs to be subjected to a dyeing process, which specifically comprises the following steps:

1) recovering pure white waste pure cotton textiles, and opening the waste cotton cloth by using a fine shuttle multifunctional opening machine to obtain waste cotton fibers;

8) soaking the nascent regenerated cellulose conductive filament obtained in the step 7) in deionized water for 2h, and drying at 50 ℃ to obtain pure white regenerated cellulose conductive filament.

9) Conventionally dyeing the pure white regenerated cellulose conductive filament obtained in the step 8) by using indigo to obtain a blue regenerated cellulose conductive filament.

TABLE 2

Table 2 shows the colour fastness of the fabrics measured according to the standards GB T5718-. As can be seen from Table 2, the colored regenerated cellulose conductive filament prepared by the invention has excellent color fastness, successfully solves the problems that the dye floats on the surface of the fabric and is easy to stain and fade after the fabric is dyed, and avoids the problems of uneven dyeing and the like caused by surface grooves of wet spinning.

TABLE 3

Examples of the invention	strength/MPa	Elongation at break/%	Conductivity S/m
				Example 2	320.49	10.26	8.84
Comparative example 2	296.85	8.32	5.62

As can be seen from table 3, in example 2, compared with comparative example 2, the mechanical properties and conductivity of the pure white regenerated cellulose conductive filament are significantly reduced after dyeing, the strength is reduced by 7%, and the conductivity is reduced by 36%. In addition, the surface of the regenerated cellulose filament is in a groove shape, and the resistance of the regenerated cellulose filament is increased due to the uneven adsorption of dye molecules, so that the conductivity of the regenerated cellulose filament is reduced.

Example 3

5) 0.2g of indium tin oxide was dispersed in 4g of dimethyl sulfoxide to obtain an indium tin oxide dispersion; during dispersion, stirring for 0.5h after every 0.5h of ultrasonic treatment;

Comparative example 3

Comparative example 3 differs from example 3 in that: the raw materials adopt brand-new undyed white pure cotton fibers, and specifically comprise the following components:

1) weighing 2g of brand-new undyed white pure cotton fiber, adding the weighed brand-new undyed white pure cotton fiber into 200ml of dilute sulfuric acid with the concentration of 0.5 wt%, heating the mixture in a water bath kettle to 75 ℃ for 2 hours, washing the mixture to be neutral by deionized water, and drying the mixture in an oven at 50 ℃ for later use;

2) freezing the fiber obtained in the step 1) by liquid nitrogen, and immediately putting the fiber into a Raymond mill to be ground into powder;

3) weighing 3g of 1-butyl-3-methylimidazolium chloride in a sealed bottle, and putting the sealed bottle in an oil bath pan at 90 ℃ until the sealed bottle is transparent; weighing 0.2g of the powder obtained in the step 2), placing the powder in a sealed bottle, and completely dissolving the fiber in an oil bath kettle at 90 ℃ to obtain a regenerated cellulose solution;

4) 0.2g of indium tin oxide was dispersed in 6g of dimethyl sulfoxide to obtain an indium tin oxide dispersion; during dispersion, stirring for 0.5h after every 0.5h of ultrasonic treatment;

5) mixing the regenerated cellulose solution obtained in the step 3) with the indium tin oxide dispersion liquid obtained in the step 4), then carrying out ultrasonic treatment for 1h under ultrasonic waves with the power of 180W and the frequency of 40kHz, and then stirring for 1h at normal temperature at the speed of 300r/min by using a magnetic stirrer to obtain a regenerated cellulose spinning solution;

6) defoaming the regenerated cellulose spinning solution obtained in the step 5), placing the regenerated cellulose spinning solution into a 20ml medical injector, then connecting a spinning needle, and carrying out wet spinning in a wet spinning device, wherein the spinning solution advancing speed is 70ml/h, the roller I speed is 20mm/s, the speed ratio of the roller II to the roller I is 1.5:1, and the receiving mode is roller receiving to obtain the nascent regenerated cellulose conductive filament;

7) soaking the nascent regenerated cellulose conductive filament obtained in the step 6) in deionized water for 2h, and drying at 50 ℃ to obtain pure white regenerated cellulose conductive filament.

As can be seen from fig. 5, the regenerated cellulose filament prepared from the waste fabric containing the dye has the same crystal structure as the regenerated cellulose filament prepared from the brand-new pure cotton, and is the conversion from cellulose I to cellulose II. The presence of the dye does not affect the properties of the regenerated cellulose fibers.

TABLE 4

Examples of the invention	strength/MPa	Elongation at break/%	Conductivity S/m
				Example 3	319.55	10.89	8.52
Comparative example 3	328.93	10.11	8.52

As can be seen from table 4, in example 3, compared with comparative example 3, the mechanical properties of the colored regenerated cellulose conductive filaments based on the recycling of waste textiles are equivalent to those of regenerated cellulose filaments based on brand-new pure cotton fibers.

Claims

1. A preparation method of colored regenerated cellulose conductive filaments based on waste textiles is characterized by comprising the following steps:

2. The method for preparing colored regenerated cellulose conductive filaments based on waste textiles according to claim 1, characterized in that in step 1), the waste textiles are textiles with different colors and different worn degrees made of fibers with cellulose as a main component.

3. The method for preparing colored regenerated cellulose conductive filaments based on waste textiles according to claim 1, characterized in that in step 2), the inorganic acid is sulfuric acid, nitric acid or hydrochloric acid.

4. The method for preparing the waste textile-based colored regenerated cellulose conductive filaments according to claim 1, characterized in that in the step 2), the treatment conditions are as follows: treating in a water bath environment at 50-90 ℃ for 0.5-3 h in inorganic acid with the concentration of 0.1-1 wt%.

5. The method for preparing colored regenerated cellulose conductive filaments based on waste textiles according to claim 1, characterized in that in step 3), the dissolution conditions are as follows: dissolving the cellulose in an oil bath environment at 70-100 ℃ for 1-6 h to obtain a regenerated cellulose solution with the concentration of 3-20 wt%.

6. The method for preparing the colored regenerated cellulose conductive filament based on the waste textiles according to the claim 1, characterized in that in the step 4), the concentration of the indium tin oxide dispersion liquid is 0.5-3 wt%; during dispersion, a mode of alternately performing ultrasonic treatment and stirring at intervals is adopted, stirring is performed for 10-40 min after every 10-40 min of ultrasonic treatment, and the total ultrasonic treatment time is 1-3 h.

7. The method for preparing colored regenerated cellulose conductive filaments based on waste textiles according to claim 1, characterized in that in step 5), the ultrasound is: the ultrasonic power is 30-8000W, and the frequency is 20-120 kHz, and the ultrasonic vibration is 0.2-2 h; the stirring is as follows: stirring the mixture in a magnetic stirrer at a speed of 0 to 1000r/min for 1 to 2 hours at normal temperature.

8. The method for preparing the colored regenerated cellulose conductive filament based on the waste textiles according to claim 1, characterized in that in step 5), the mass ratio of the indium tin oxide dispersion liquid to the regenerated cellulose solution is 1-5: 1.

9. The method for preparing the waste textile-based colored regenerated cellulose conductive filaments according to claim 1, wherein in the step 6), the coagulation bath for wet spinning is deionized water at 25-70 ℃, and the spinning conditions are as follows: the spinning solution advancing speed is 40-100 ml/h, the diameter of a spinning needle head is 0.45-1.2 mm, the speed of a roller I is 20-50 mm/s, and the speed ratio of a roller II to a roller I is 1-3: 1; the speed of the winding roller is the same as that of the second roller.

10. The method for preparing the waste textile-based colored regenerated cellulose conductive filament according to claim 1, characterized in that a step is added between the step 2) and the step 3): freezing the fiber obtained in the step 2) by liquid nitrogen, and immediately putting the fiber into a grinding machine to be ground into powder.