Flame-retardant finishing device and method for flax fibers using supercritical carbon dioxide

Abstract

The application discloses a flax fiber supercritical carbon dioxide flame-retardant finishing device, which comprises a supercritical carbon dioxide preparation system, wherein the supercritical carbon dioxide preparation system comprises, which are sequentially connected, a carbon dioxide gas cylinder, a filter, a refrigerating device, a high-pressure pump and a preheater; the preheater is connected with the inlet of a mixer; a cosolvent kettle body is further connected to the inlet of the mixer; the outlet of the mixer is connected with a flame-retardant finishing kettle; the flame-retardant finishing kettle comprises a plurality of hollow lifting spray rods connected to the bottom of the flame-retardant finishing kettle; the hollow lifting spray rods are provided with spray heads; the hollow lifting spray rods are provided with spray rod lifting inner sleeve pipes; one end of the spray rod lifting inner sleeve pipes is connected with the spray heads, the other end of the spray rod lifting inner sleeve pipes is connected with the mixer and extends from the bottom of the flame-retardant finishing kettle, and the outer wall of the spray rod lifting inner sleeve pipes is fixedly connected with the bottom of the flame-retardant finishing kettle; a plurality of spray holes are arranged on the hollow lifting spray rods; and a communication hole, which is in communication with the inside of the hollow lifting spray rods, is further arranged at the position close to the top of the spray rod lifting inner sleeve pipes.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of flax fibers, in particular to a flax fiber supercritical carbon dioxide flame-retardant finishing device and finishing method. BACKGROUND

[0002] Flax (scientific name: Linum usitatissimum) is the earliest high-quality plant fiber used by humans, accounting for 1.5% of the total amount of natural fibers. The chemical composition of flax fiber mainly includes cellulose, hemicellulose, lignin, pectin and wax, etc. Among them, the cellulose content is 70%-80%, the hemicellulose content is 12%-15%, the lignin content is 2.5%-5%, the pectin content is 1.4%-5.7%, the wax content is 1.2%-1.8%, and the nitrogen-containing substance content is 0.3%-0.6%. With the gradual depletion of oil resources, flax has excellent moisture absorption, quick drying, air permeability, smoothness, antibacterial health, acid and alkali resistance, corrosion resistance and other characteristics, and has good health care performance and unique style of air permeability, smoothness, ruggedness, boldness, natural texture, soft color tone, stiffness and generosity. It is increasingly valued and concerned by people and is widely used in textile and garment, home decoration, aerospace, medical and health and many other fields. From the perspective of safety and fire prevention, the flame-retardant finishing of flax fiber is becoming increasingly important and is attracting the attention of textile engineering and technical personnel.

[0003] With the development of global economy and the improvement of people's living standards, higher requirements for flax fiber follow. Since the mid-1970s, flax fiber has been prone to fire, and on the other hand, the demand for flax fiber in industry is increasing, but the flame-retardant treatment of flax fiber has always been a technical barrier in this field. In recent years, with the continuous development of China's economic strength, light industry has become a pillar industry in China, and the requirement for industrial technology is getting higher and higher, so the process research of flame-retardant flax fiber has become a hot research problem in this field.

[0004] Traditional flame-retardant finishing of flax fiber is to coat a thin film on the surface of flax fiber to achieve flame-retardant effect. The current research on flame-retardant method of flax fiber not only has high cost and complex process, but also uses a large amount of halogen elements in the flame retardant, which will release a lot of toxic gases when burning. At the same time, a large amount of toxic waste liquid is also produced in the finishing process, causing great pollution to the environment. On the other hand, the flame-retardant effect is not very good, which is difficult to meet the needs of the market.

[0005] Patent No. 202110269691 discloses "a feather fiber supercritical CO2 water-free cleaning device and its cleaning method", but the cleaning unit in this patent mainly focuses on cleaning feather fiber and removing impurities on the surface of feather fiber. The cleaning liquid hardly enters the inside of the fiber. SUMMARY

[0006] The purpose of the present application is to provide a flax fiber supercritical carbon dioxide flame-retardant finishing device.

[0007] The present application also provides a flax fiber supercritical carbon dioxide flame-retardant finishing method.

[0008] Compared with the traditional flame-retardant finishing method, the outstanding feature of the present application is a flax fiber supercritical carbon dioxide flame-retardant finishing device and finishing method. The flame-retardant finishing method of the present application can adjust the height of the hollow lifting spray rod as needed. During the finishing process, the flame retardant is sprayed from the spray holes and spray heads of multiple hollow lifting spray rods to enhance the permeability of the flame retardant and improve the uniformity of the flame-retardant finishing. The whole process of flame-retardant finishing is energy-saving and emission-reducing, and zero-pollution to the environment. This finishing method has certain application value and plays a positive role in promoting the flame-retardant finishing of flax fiber.

[0009] To achieve the above-mentioned application purposes, the technical solution of the present application is: a flax fiber supercritical carbon dioxide flame-retardant finishing device, comprising a supercritical carbon dioxide preparation system, the supercritical carbon dioxide preparation system comprises a carbon dioxide gas cylinder, a filter, a refrigerator, a high-pressure pump and a preheater connected in sequence, the preheater is connected with the inlet of a mixer, and a cosolvent kettle body is further connected to the inlet of the mixer, the outlet of the mixer is connected with a flame-retardant finishing kettle; the flame-retardant finishing kettle comprises a plurality of hollow lifting spray rods connected at the bottom of the flame-retardant finishing kettle, a spray head is arranged on the hollow lifting spray rod, a spray rod lifting inner sleeve is arranged in the hollow lifting spray rod, one end of the spray rod lifting inner sleeve is connected with the spray head, the other end of the spray rod lifting inner sleeve extends from the bottom of the flame-retardant finishing kettle and is connected with the mixer, and the outer wall of the spray rod lifting inner sleeve and the bottom of the flame-retardant finishing kettle are fixedly connected, a plurality of spray holes are arranged on the hollow lifting spray rod, and a communication hole communicating with the inside of the hollow lifting spray rod is further arranged at the top of the spray rod lifting inner sleeve.

[0010] Further, the number of spray holes is 6-20, and the aperture is 1-5 mm.

[0011] Further, the spray rod lifting inner sleeve is connected with the mixer through a supercritical carbon dioxide fluid pipeline.

[0012] Further, the hollow lifting spray rod and the spray rod lifting inner sleeve are composed of a plurality of levels of pipes with increasing diameters from top to bottom; the upper and lower levels of pipes are limited by annular clamping plates.

[0013] Further, the flame-retardant finishing kettle is externally provided with an internal circulation pipeline in communication with the flame-retardant finishing kettle, both ends of the internal circulation pipeline are in communication with the flame-retardant finishing kettle, a circulating pump is arranged on the internal circulation pipeline, and an external circulation pipeline connected with the rear end of the refrigerating device is further arranged on the internal circulation pipeline.

[0014] A method for flame-retardant finishing of flax fibers by supercritical carbon dioxide, comprising the following steps:

[0015] 1-100 ml of flame retardant dimethyl methylphosphonate, 1-100 ml of carbon tetrachloride solution are added to 1-500 ml of emulsifier solution containing PPTA O, and are uniformly mixed and emulsified, then 1-100 ml of tetraethyl orthosilicate (TEOS) and 1-100 ml of ethanol are added to obtain a mixed solution of the flame retardant;

[0016] The mixed solution of the flame retardant is placed in the cosolvent kettle body, and is injected into the mixer at a flow rate of 1-50 ml / min;

[0017] The mixed solution of the flame retardant and carbon dioxide are uniformly mixed in the mixer under the conditions of a temperature of 35-60°C, a pressure of 8-15 MPa, a time of 5-30 min, and a carbon dioxide flow rate of 5-10 g / min, so as to reach a supercritical state;

[0018] 1-50 kg of flax fibers are placed in the flame-retardant finishing kettle, and when the mixed solution of the flame retardant and carbon dioxide reach the supercritical state, the mixed solution of the flame retardant and carbon dioxide enter the flame-retardant finishing kettle, and the flax fibers are subjected to flame-retardant finishing under the conditions of a temperature of 35-120°C, a pressure of 8-30 MPa, a time of 20-150 min, and a carbon dioxide flow rate of 5-30 g / min.

[0019] Further, after the flame-retardant finishing is completed, clean carbon dioxide is introduced for cleaning, and during the cleaning process, the temperature is kept at 35-40°C, the pressure is kept at 8-10 MPa, and the cleaning time is kept at 10-30 min.

[0020] Further, after the cleaning is completed, the mixed solution of the flame retardant is separated and recovered.

[0021] The present application has the following beneficial effects:

[0022] 1. The experimental operation in the present application is simple, the cost is low, the flame retardancy is good, and there is no pollutant harmful to the environment before and after combustion, thereby providing a new method for formaldehyde-free, non-toxic and harmless flame-retardant finishing of cellulose fibers.

[0023] 2. The finishing process in the present application is pollution-free and zero-emission, and can change the traditional high-consumption and high-pollution processing mode of flax fibers, and has an important guiding role and actual benefit for the technological transformation and upgrading of the hemp textile industry. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 This is a flowchart of a flame-retardant finishing device.

[0025] Figure 2 This is a schematic diagram of the structure of a flame-retardant finishing kettle. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will now be clearly and completely described in conjunction with the accompanying drawings.

[0027] Example 1: As Figure 1 , 2 As shown, a supercritical carbon dioxide flame-retardant finishing device for flax fibers includes a supercritical carbon dioxide preparation system. The supercritical carbon dioxide preparation system comprises a carbon dioxide cylinder 1.1, a filter 1.2, a cooler 1.3, a high-pressure pump 1.4, and a preheater 1.5 connected in sequence. The preheater 1.5 is connected to the inlet of a mixer 2. A co-solvent vessel 3 is also connected to the inlet of the mixer 2. The outlet of the mixer 2 is connected to a flame-retardant finishing vessel 4. The flame-retardant finishing vessel 4 includes several hollow lifting spray bars 5 connected to the bottom of the flame-retardant finishing vessel 4. The hollow lifting spray bar 5 is equipped with a nozzle 6. Inside the hollow lifting spray bar 6 is a lifting inner sleeve 7. One end of the lifting inner sleeve 7 is connected to the nozzle 6, and the other end extends from the bottom of the flame-retardant finishing vessel 4 and connects to the mixer 2. The outer wall of the lifting inner sleeve 7 is fixedly connected to the bottom of the flame-retardant finishing vessel 4. The hollow lifting spray bar 5 has several spray holes 5.1. Near the top of the lifting inner sleeve 7, there is also a connecting hole 7.1 that communicates with the interior of the hollow lifting spray bar 5. The number of spray holes 5.1 is 6 to 20, and the diameter is 1 to 5 mm. The lifting inner sleeve 7 is connected to the mixer 2 through a supercritical carbon dioxide fluid pipe 9.

[0028] The hollow lifting spray bar 5 and the inner sleeve 7 of the spray bar lifting are composed of several stages of tubes with progressively increasing diameters from top to bottom; the several stages of tubes are limited up and down by annular clamping plates 8.

[0029] The flame-retardant finishing vessel 4 is provided with an internal circulation pipe 10 connected to the flame-retardant finishing vessel 4. Both ends of the internal circulation pipe 10 are connected to the flame-retardant finishing vessel 4. A circulation pump 11 is provided on the internal circulation pipe 10. An external circulation pipe 12 connected to the rear end of the cooler 1.3 is also provided on the internal circulation pipe 10. A separation vessel 13 is provided on the external circulation pipe 12.

[0030] Example 2: A method for supercritical carbon dioxide flame retardant finishing of flax fibers, comprising the following steps:

[0031] Add 1 ml of flame retardant dimethyl methylphosphonate and 1 ml of carbon tetrachloride solution to 1 ml of solution containing emulsifier Pingpingjia O, mix them thoroughly and emulsify them, then add 1 ml of tetraethyl orthosilicate (TEOS) and 1 ml of ethanol to obtain a mixture of flame retardants.

[0032] Put the flame retardant mixture into the cosolvent kettle body, inject it into the mixer at a flow rate of 1 ml / min;

[0033] Mix the flame retardant mixture and carbon dioxide in the mixer under the conditions of temperature 35°C, pressure 8 MPa, time 5 min, and carbon dioxide flow rate 5 g / min to achieve supercritical state;

[0034] Put 1 kg of flax fibers into the flame-retardant finishing kettle. When the flame retardant mixture and carbon dioxide reach supercritical state, enter the flame-retardant finishing kettle. Perform flame-retardant finishing on the flax fibers under the conditions of temperature 35°C, pressure 8 MPa, time 20 min, and carbon dioxide flow rate 5 g / min.

[0035] After the flame-retardant finishing is completed, clean it with clean carbon dioxide. Maintain the temperature at 35°C and the pressure at 8 MPa during the cleaning process. The cleaning time is 10 min.

[0036] After the cleaning is completed, separate and recover the flame retardant mixture.

[0037] After the finishing, the limiting oxygen index (LOI) of the flax fibers reaches 30.

[0038] Example 3: A supercritical carbon dioxide flame-retardant finishing method for flax fibers, comprising the following steps:

[0039] Add 50 ml of flame retardant dimethyl methylphosphonate and 50 ml of carbon tetrachloride solution to 200 ml of emulsifier solution containing Plenag O, mix them thoroughly and evenly, and then add 50 ml of tetraethyl orthosilicate (TEOS) and 50 ml of ethanol to obtain a flame retardant mixture;

[0040] Put the flame retardant mixture into the cosolvent kettle body, inject it into the mixer at a flow rate of 20 ml / min;

[0041] Mix the flame retardant mixture and carbon dioxide in the mixer under the conditions of temperature 50°C, pressure 12 MPa, time 15 min, and carbon dioxide flow rate 8 g / min to achieve supercritical state;

[0042] Put 25 kg of flax fibers into the flame-retardant finishing kettle. When the flame retardant mixture and carbon dioxide reach supercritical state, enter the flame-retardant finishing kettle. Perform flame-retardant finishing on the flax fibers under the conditions of temperature 80°C, pressure 20 MPa, time 80 min, and carbon dioxide flow rate 20 g / min.

[0043] After the flame-retardant finishing is completed, clean it with clean carbon dioxide. Maintain the temperature at 38°C and the pressure at 9 MPa during the cleaning process. The cleaning time is 20 min.

[0044] After the cleaning, the flame retardant mixed solution is separated and recovered.

[0045] After the finishing, the limit oxygen index (LOI) of the flax fiber reaches 32.

[0046] Embodiment 4: A supercritical carbon dioxide flame-retardant finishing method for flax fiber, comprising the following steps:

[0047] 100ml of flame retardant dimethyl methylphosphonate, 100ml of carbon tetrachloride solution are added to 500ml of emulsifier solution containing emulsifier PPG-0, and mixed and emulsified uniformly, then 100ml of tetraethyl orthosilicate (TEOS) and 100ml of ethanol are added to obtain a mixed solution of flame retardants;

[0048] The flame retardant mixed solution is placed in a cosolvent kettle body, and injected into the mixer at a flow rate of 50ml / min;

[0049] The flame retardant mixed solution and carbon dioxide are mixed uniformly in the mixer at a temperature of 60°C, a pressure of 15MPa, a time of 30min, and a carbon dioxide flow rate of 10g / min to reach a supercritical state;

[0050] 50kg of flax fiber is placed in the flame-retardant finishing kettle, and when the flame retardant mixed solution and carbon dioxide reach a supercritical state, it enters the flame-retardant finishing kettle, and the flax fiber is subjected to flame-retardant finishing at a temperature of 120°C, a pressure of 30MPa, a time of 150min, and a carbon dioxide flow rate of 30g / min.

[0051] After the flame-retardant finishing, clean carbon dioxide is introduced, and the temperature is maintained at 40°C, the pressure is maintained at 10MPa, and the cleaning time is 30min.

[0052] After the cleaning, the flame retardant mixed solution is separated and recovered.

[0053] After the finishing, the limit oxygen index (LOI) of the flax fiber reaches 29.

[0054] When working: the lifting height of the hollow lifting spray rod 5 and the spray rod lifting inner sleeve 7 can be adjusted by adjusting the supercritical liquid pressure of the flame retardant mixed solution and carbon dioxide in the mixer 2 entering the flame-retardant finishing kettle 4.

[0055] The described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

Claims

1. A device for supercritical carbon dioxide flame-retardant finishing of flax fibers, characterized in that, The application relates to a supercritical carbon dioxide preparation system, which comprises a carbon dioxide gas cylinder, a filter, a refrigerating device, a high-pressure pump and a preheater which are sequentially connected, the preheater is connected with a mixer inlet, a cosolvent kettle body is further connected to the mixer inlet, and the mixer outlet is connected with a flame-retardant finishing kettle; the flame-retardant finishing kettle comprises a plurality of hollow lifting spray rods which are connected to the bottom of the flame-retardant finishing kettle, a spray head is arranged on the hollow lifting spray rod, a spray rod lifting inner sleeve is arranged in the hollow lifting spray rod, one end of the spray rod lifting inner sleeve is connected with the spray head, the other end of the spray rod lifting inner sleeve extends from the bottom of the flame-retardant finishing kettle and is connected with the mixer, the outer wall of the spray rod lifting inner sleeve is fixedly connected with the bottom of the flame-retardant finishing kettle, a plurality of spray holes are arranged on the hollow lifting spray rod, and a communication hole which is connected with the inside of the hollow lifting spray rod is further arranged at the top of the spray rod lifting inner sleeve.

2. The flax fiber supercritical carbon dioxide flame-retardant finishing device according to claim 1, characterized in that, The number of the spray holes is 6-20, and the aperture is 1-5 mm.

3. The flax fiber supercritical carbon dioxide flame-retardant finishing device according to claim 1, characterized in that, The spray rod lifting inner sleeve is connected with the mixer through a supercritical carbon dioxide fluid pipeline.

4. The flax fiber supercritical carbon dioxide flame-retardant finishing device according to claim 1, characterized in that, The hollow lifting spray rod and the spray rod lifting inner sleeve are composed of a plurality of stage pipes which are sequentially increased in diameter from top to bottom; the upper and lower stage pipes are limited through annular clamping plates.

5. The flax fiber supercritical carbon dioxide flame-retardant finishing device according to claim 1, characterized in that, An inner circulation pipeline which is connected with the flame-retardant finishing kettle is arranged outside the flame-retardant finishing kettle, both ends of the inner circulation pipeline are connected with the flame-retardant finishing kettle, a circulating pump is arranged on the inner circulation pipeline, an outer circulation pipeline which is connected with the rear end of the refrigerating device is further arranged on the inner circulation pipeline, and a separation kettle is arranged on the outer circulation pipeline.

Images