Method for improving dissolution efficiency of PE in toluene in microfiber production based on biological lipase catalysis method

Abstract

The invention discloses a method for improving dissolution efficiency of PE (polyethylene) in methylbenzene in microfiber production based on a biological lipase catalysis method, which comprises the following specific operation processes: premixing lipase powder and absolute ethyl alcohol, performing magnetic stirring or ultrasonic treatment to form a suspension, injecting the suspension into a methylbenzene solvent, starting an emulsification pump to prepare enzyme-containing methylbenzene, and adding the enzyme-containing methylbenzene into a reaction kettle; according to the method, the acting force between PE molecular chains is weakened through enzyme catalysis nucleophilic attack and hydrogen-bond interaction, the permeation efficiency of the toluene is remarkably enhanced, meanwhile, the crystallinity of the PE and the interfacial tension between the PE and the toluene are reduced, toluene wetting and capillary tube permeation are promoted, and the microfiber Bass is prepared. According to the invention, the lipase is added into the PE, so that toluene directionally permeates into the PE, the molecular chain of the PE is accelerated to be completely separated from the crystal structure, and the lipase is possibly combined with the PE through hydrophobic interaction to form an enzyme-substrate compound, so that the dispersity is improved, and the dissolution of the PE in toluene is accelerated. And compared with the traditional process, the production efficiency can be greatly improved, and the energy consumption is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of manufacturing microfiber synthetic leather, and particularly relates to a method for improving the dissolution efficiency of PE in toluene in microfiber production based on a biological lipase catalysis method. BACKGROUND

[0002] In the traditional microfiber bess production process, the reduction of the marine component polyethylene (PE) requires 80 DEG C high temperature treatment for 2-4 hours to dissolve PE, and there are defects such as high energy consumption (steam consumption accounts for 30-40% of the cost), low efficiency (PE dissolution rate is less than or equal to 93%), and high safety risk (flash explosion accident is easy to occur due to volatilization of toluene at high temperature). The existing improvement scheme such as increasing the amount of toluene will increase the safety risk; the steam condensate water waste heat is used to heat the PE / toluene solution, but it still needs to maintain high temperature operation above 80 DEG C; and the addition of surfactant easily causes fiber pollution. SUMMARY

[0003] In view of the above problems, the purpose of the present application is to provide a method for improving the dissolution efficiency of PE in toluene in microfiber production based on a biological lipase catalysis method.

[0004] The specific technical scheme is as follows:

[0005] A method for improving the dissolution efficiency of PE in toluene in microfiber production based on a biological lipase catalysis method, comprising the following steps:

[0006] 1) Pre-mixing with ethanol: mixing lipase powder with anhydrous ethanol, and forming a suspension by magnetic stirring or ultrasonic treatment;

[0007] 2) Mixing with toluene: injecting the suspension of step 1) into toluene solvent, and starting an emulsifying pump to prepare enzyme-containing toluene;

[0008] 3) Pumping the enzyme-containing toluene of step 2) into a dissolution tank for catalytic reduction treatment of microfiber bess.

[0009] Further, the lipase in step 1) is a solvent-resistant lipase selected from Candida lipase, Aspergillus lipase or Rhizomucor lipase.

[0010] Further, the addition amount of the lipase is 0.1-1.5% of the mass of the toluene solvent, and the catalytic reduction treatment is carried out at 65-80 DEG C.

[0011] Further, the mass ratio of the lipase powder to anhydrous ethanol in step 1) is 1:10-20, the magnetic stirring speed is 500-1000 rpm, the ultrasonic treatment condition is 200 W, 40 kHz, and the magnetic stirring or ultrasonic treatment time is 10-15 minutes.

[0012] Further, the operating condition of the emulsifying pump in step 2) is rotation speed ≥ 3000 rpm, linear speed is 10-15 m / s, and the continuous circulation lasts for 30-60 minutes.

[0013] Further, the time for catalytic reduction treatment is 20-150 minutes.

[0014] Preferably, the added amount of lipase is 0.85-1.0% of the mass of the toluene solvent.

[0015] The beneficial effects of the present application are:

[0016] The present application significantly enhances the toluene penetration efficiency by weakening the intermolecular forces of PE through enzyme-catalyzed nucleophilic attack and hydrogen bonding, reduces the crystallinity of PE and the interfacial tension between PE and toluene, promotes toluene wetting and capillary penetration, and accelerates the complete separation of PE molecular chains from the crystal structure. The lipase may be combined with PE through hydrophobic interaction to form an "enzyme-substrate complex", improving the dispersibility and thus accelerating the dissolution of PE in toluene. At the same temperature, the dissolution time of PE in toluene can be significantly shortened, and at low temperature, the same dissolution time as at high temperature can be achieved, greatly improving the dissolution efficiency of superfine fibers in toluene and significantly reducing energy consumption, providing strong technical support for green and low-carbon manufacturing of superfine fibers. DETAILED DESCRIPTION

[0017] The present application will be further described below in conjunction with examples, but the scope of protection of the present application is not limited thereto.

[0018] In order to more intuitively observe the dissolution speed of PE in toluene, in the following implementation examples, the sea component PE particles are used instead of the superfine fiber base fabric without extraction reduction. The toluene with added lipase is placed in a transparent glass bottle to facilitate observation of the dissolution of PE particles therein, and a water bath is used to control the temperature of the system, so as to more accurately and stably confirm the dissolution of PE in the toluene system with added lipase at different temperatures.

[0019] Example 1

[0020] 1) 0.5 g of Candida lipase powder is premixed with anhydrous ethanol (mass ratio 1:10), and magnetic stirring (800 rpm) is performed for 10 minutes to form a suspension;

[0021] 2) The suspension of step 1) is injected into 50 g of toluene, and a high-speed shearing emulsifying pump (rotation speed 3500 rpm, linear speed 12 m / s) is started to circulate for 30 minutes to prepare enzyme-containing toluene;

[0022] 3) The enzyme-containing toluene of step 2) was added into a transparent glass bottle, and the glass bottle was placed in a water bath at 80°C. When the temperature of the liquid in the bottle reached 80°C, 1.5 g of PE particles were added, and the catalytic dissolution process of the PE particles was observed and recorded. The complete dissolution time was 22 minutes.

[0023] Examples 2-4

[0024] The amount of lipase was changed, and the other operating conditions were the same as in Example 1. The operating conditions and complete dissolution times are shown in Table 1.

[0025] Table 1 Effect of different lipase contents on the dissolution rate of PE in toluene at 80°C

[0026]

[0027] As shown in Table 1, under the condition of 80°C and the same other conditions, the addition of a certain amount of lipase to toluene can significantly reduce the dissolution time of PE. When the amount of lipase is 0.25 g, i.e., 0.5% of toluene, the dissolution time of PE is reduced by 25.9% compared to no addition. When the amount of lipase is increased to 0.5 g, i.e., 1%, compared to 0.5% of lipase content, the dissolution time does not continue to decrease, indicating that the catalytic effect has reached the optimal value at 0.5%, and the excess lipase does not accelerate the dissolution, but the time is longer than that of 0.5%. This is mainly because when the concentration of lipase is too high, the enzyme will self-aggregate, wrap part of the PE molecules, hinder their contact with the solvent, and form a dense layer of excess lipase on the surface of PE, physically blocking the contact between toluene and PE. At the same time, high-concentration lipase greatly increases the viscosity of the toluene system, reduces the diffusion rate of toluene molecules, and thus slows down the dissolution kinetics of PE.

[0028] Examples 5-11

[0029] The operating process was the same as in Example 1, and the operating temperature was changed to 70°C. The effect of different lipase contents on the dissolution rate of PE in toluene was studied, and the results are shown in Table 2.

[0030] Table 2 Effect of different lipase contents on the dissolution rate of PE in toluene at 70°C

[0031]

[0032]

[0033] From Table 2, it can be concluded that under the condition of 70°C, with other conditions being the same, adding a certain amount of lipase into toluene can also significantly reduce the dissolution time of PE. When 0.425g of lipase is added, i.e. the lipase accounts for 0.85% of toluene, the PE dissolution time is reduced by 66.3% compared to no addition, and the dissolution rate is increased by 196%, and the dissolution time is 27min, reaching the dissolution rate under the conventional condition of 80°C. That is, by adding lipase, the PE can reach the same dissolution rate under high-temperature condition under low-temperature condition, thereby the energy consumption can be significantly reduced. When the proportion of lipase continues to increase, the dissolution time of PE will also decrease, but the degree of reduction has started to become small, which is consistent with the rule in Examples 1-4. Similarly, because of the self-aggregation of excessive lipase and the formation of a dense layer on the surface of PE, the catalytic efficiency is reduced.

[0034] Examples 12-16

[0035] The operation process is the same as that in Example 1, and the operation temperature is changed to 65°C, and the effect of different lipase contents on the dissolution rate of PE in toluene is studied, and the results are shown in Table 3.

[0036] Table 3 Effect of different lipase contents on the dissolution rate of PE in toluene at 65°C

[0037]

[0038] From Table 3, it can be concluded that under the condition of 65°C, with other conditions being the same, adding a certain amount of lipase into toluene can also significantly reduce the dissolution time of PE. When 0.5g of lipase is added, i.e. the lipase accounts for 1% of toluene, the PE dissolution time is reduced by 64.8% compared to no addition, and the dissolution rate is increased by 184%. But when the proportion of lipase continues to increase, the dissolution time does not continue to shorten, and the principle is the same as in Examples 1-4. But under the condition of 65°C, the overall dissolution rate is already much lower than that at 80°C or 70°C, mainly because the activity of lipase is limited at a lower temperature, and the lower activity leads to a decrease in its catalytic effect.

Claims

1. A method for improving the dissolution efficiency of PE in toluene in microfiber production based on biolipase catalysis, characterized by, The method comprises the following steps: 1) mixing with ethanol: mixing lipase powder with anhydrous ethanol to form a suspension by magnetic stirring or ultrasonic treatment; 2) mixing with toluene: injecting the suspension of step 1) into toluene solvent, starting an emulsification pump to prepare enzyme-containing toluene; 3) pumping the enzyme-containing toluene of step 2) into a dissolving tank to perform catalytic weight reduction treatment of microfiber.

2. The method for improving the dissolution efficiency of PE in toluene in microfiber production based on biological lipase catalysis according to claim 1, characterized in that, The lipase in step 1) is a solvent-tolerant lipase selected from Candida lipase, Aspergillus lipase or Rhizomucor lipase.

3. The method for improving the dissolution efficiency of PE in toluene in microfiber production based on biological lipase catalysis according to claim 2, characterized in that, The amount of lipase added is 0.1-1.5% of the mass of toluene solvent, and the catalytic weight reduction treatment is performed at 65-80°C.

4. The method for improving the dissolution efficiency of PE in toluene in microfiber production based on biological lipase catalysis according to claim 1, characterized in that, The mass ratio of lipase powder to anhydrous ethanol in step 1) is 1:10-20, the magnetic stirring speed is 500-1000 rpm, the ultrasonic treatment conditions are 200W, 40kHz, and the magnetic stirring or ultrasonic treatment time is 10-15 minutes. The operating conditions of the emulsification pump in step 2) are rotation speed ≥3000 rpm, linear speed 10-15 m / s, and continuous circulation for 30-60 minutes.

5. The method for improving the efficiency of PE dissolution in toluene in microfiber production based on biological lipase catalysis according to claim 1, characterized in that, The catalytic weight reduction treatment time is 20-150 minutes. The amount of lipase added is 0.1-1.5% of the mass of toluene solvent.

6. The method for improving the efficiency of PE dissolution in toluene in microfiber production based on biological lipase catalysis according to claim 1, characterized in that, ​ 7. The method for improving the efficiency of PE dissolution in toluene in microfiber production based on biological lipase catalysis according to claim 3, characterized in that, ​ 0.85-1.0％。

Images