CN115534454A - Nanofiber composite vehicle-mounted air filter paper with gradient structure and preparation method thereof - Google Patents

Abstract

The invention proposes a nanofiber composite vehicle-mounted air filter paper with a gradient structure and its preparation method, which is used to solve the technical problems of poor bonding fastness and low filtration efficiency between nanofibers and substrates in the nanofiber filter material. The invention utilizes a preparation process combining electrospinning and electrostatic spraying to prepare nanofiber composite vehicle air filter paper, which includes an ultrafine nanofiber net layer, a nanofiber layer and a filter paper layer arranged in sequence. The invention has an initial filtration efficiency of PM _0.3 particles up to 99.9% under the condition of industrial standard wind speed, reaching the H12 standard of the air filter material. More importantly, in the self-cleaning backflush test, the PM _0.3 filtration efficiency can still maintain more than 90% after 10,000 backflush tests. This provides a new strategy for high-performance nanofiber filter materials, which is of great significance to the high-tech, high-quality, green and sustainable development of non-woven materials and filter materials.

Description

A nanofiber composite vehicle air filter paper with gradient structure and its preparation method

technical field

The invention belongs to the technical field of air purification, and in particular relates to a nanofiber composite vehicle-mounted air filter paper with a gradient structure and a preparation method thereof.

Background technique

As an important part of the air intake system, the air filter element of the automobile engine can effectively filter out the dust or sand particles suspended in the air, so as to reduce the wear of related parts such as valves, cylinders, pistons, etc. "Cylinder" phenomenon, so that the engine can work under normal conditions, thereby improving the overall service time of the engine. When the engine is working normally, the air first enters the intake manifold after being filtered by the filter element, then passes through the throttle valve and the intake regulator box in turn, and finally flows into the cylinder of the engine. If the air filter is not installed, the unfiltered air will not be able to burn normally in contact with the fuel of the vehicle, and carbon deposits will easily occur in the engine cylinder. In severe cases, it will cause weak acceleration during the driving process of the vehicle and affect exhaust emissions. In addition, due to the use of the engine air filter element, the engine intake resistance is bound to increase, which not only affects the power output of the engine, but also affects the economic performance of the engine. It can be seen that the air filter can improve the life of the engine and ensure the stable output of power.

In the traditional electrospinning process, the diameter of the nanofibers prepared by it is 100-300nm, and the nanofiber membranes prepared by it still have the mechanical and chemical properties of the original raw materials, but due to the thick fiber diameter and large pore size, it is difficult for air The low interception performance of particles of various scales limits the application of high-performance nanofibers in air filter materials.

Electrostatic spraying technology is different from traditional electrospinning processing technology. It mainly relies on the action of high-voltage electrostatic field to make polymer solution form pendant cone-shaped droplets at the end of the nozzle, which researchers call Taylor cones. When the charge repulsion on the surface of the droplet exceeds its surface tension, the dangling droplet begins to split to form numerous small droplets, referred to as "spray"; these droplets are accompanied by the stretching effect of the electric field force during the high-speed flight in the electric field. The solvent evaporates, solidifies and self-assembles into the forming mechanism, and finally deposits on the grounded receiver to form a polymer network of fibers. Its diameter is generally distributed between 10-30nm. The ultra-fine nanofiber web formed by electrostatic spraying has the characteristics of small pore size and high porosity, but also has the characteristics of low strength.

In addition, most of today's researchers focus on the modification of nanofibers themselves, and there is little research on the bonding fastness between nanofibers and substrates. In actual application and testing, the fastness between nanofibers and substrates will seriously affect their filtration performance. Especially in the self-cleaning backflushing test (one of the standard tests in the air filter material industry), the poor adhesion fastness will greatly reduce the filtration performance of the nanofiber filter material and cannot be reused, which greatly limits the practical use of nanofibers. application.

Contents of the invention

Aiming at the technical problems of poor bonding fastness and low filtration efficiency between nanofibers and substrates in nanofiber filter materials, the present invention proposes a nanofiber composite vehicle air filter paper with a gradient structure and a preparation method thereof. Composite car air filter paper not only has excellent filtration performance, but also has a firm bond between the nanofiber and the substrate, and can maintain good dimensional stability and mechanical strength after repeated cleaning, and can maintain stable filtration of particulate matter for a long time.

In order to achieve the above object, the technical solution of the present invention is achieved in that:

A preparation method of a nanofiber composite vehicle-mounted air filter paper with a gradient structure, comprising the following steps:

(1) Stirring and dissolving the polymer I, the adhesive and the curing agent in sequence in the solvent I to prepare a nanofiber spinning solution;

(2) stirring and dissolving triethylamine salt, polymer II, adhesive and curing agent into solvent II in sequence to prepare ultrafine nanofiber spinning solution;

(3) The nanofiber spinning solution prepared in step (1) is spun by electrospinning technology, the receiving substrate is filter paper, and a layer of nanofiber is sprayed to obtain a nanofiber membrane filter paper;

(4) The ultrafine nanofiber spinning solution prepared in step (2) is spun by electrostatic spray technology, and the receiving substrate is the nanofiber membrane filter paper prepared in step (3), sprayed with a layer of ultrafine nanofiber net, multilayer composite filter paper

(5) bonding each layer of the multilayer composite filter paper prepared in step (4) together through a hot-press composite process to obtain a nanofiber composite vehicle-mounted air filter paper.

Preferably, the polymer I needs to be dried in advance, the drying temperature is 50-75°C, and the drying time is at least 2 hours.

Preferably, the polymer II needs to be dried in advance at a drying temperature of 50-75° C. and a drying time of at least 2 hours.

In the step (1), the mass ratio of the adhesive to the polymer I is 1: (2-5), the mass ratio of the curing agent to the polymer I is 1: (10-100), the mass of the solvent I and the polymer I The ratio is (12-25):1.

In the step (2), the mass ratio of triethylamine salt to polymer II is 1: (5-8), the mass ratio of adhesive to polymer II is 1: (2-5), and the curing agent and polymer II The mass ratio of solvent II and polymer II is (12-25):1.

The polymer I is polystyrene or polyacrylonitrile; the solvent I is N,N dimethylacetamide or N,N dimethylformamide; the polymer II is polyvinylidene fluoride or polyurethane; Solvent II is N,N dimethylacetamide or N,N dimethylformamide; the adhesive in the step (1) or (2) is ethyl acrylate, and the curing agent is polyetheramine; Triethylamine salt is any one or a combination of two or more of triethylamine hydrochloride, triethylamine sulfate or triethylamine nitrate; preferably, the triethylamine salt is triethylamine hydrochloride .

Preferably, the curing agent in the step (1) or (2) is polyether ZT-143 curing agent.

The dissolution conditions of each component in the step (1) are as follows: the stirring and dissolving temperature of the polymer I is 60-70°C; the stirring and dissolving temperature of the adhesive is 40-55°C; the stirring and dissolving temperature of the curing agent is 20-25°C , the stirring time is 10-30min.

The dissolution conditions of each component in the step (2) are as follows: the stirring and dissolving temperature of triethylamine salt is 60-70°C; the stirring and dissolving temperature of polymer II is 80-120°C; the stirring and dissolving temperature of adhesive is 40-70°C. 55°C; the stirring and dissolving temperature of the curing agent is 20-25°C, and the stirring time is 10-30min.

Preferably, the stirring and dissolving time of the adhesive in the step (1) or step (2) is 2-4 hours.

The parameters of the electrospinning technology in the step (3) are: the spinning voltage of the high-voltage generator is 10-80KV, the distance from the nozzle to the receiving base cloth is 15-20cm, and the nozzle diameter is 0.15-0.3cm. The flow rate of the electrospinning solution is 0.5-1.5mL/h.

By controlling the receiving time of electrospinning, the thickness of the nanofiber membrane can be regulated, and the receiving time can be controlled according to actual needs. Preferably, the receiving time is 5-30 minutes.

The filter paper in the step (3) is cellulose filter paper; preferably, the pore size distribution of the cellulose filter paper is 75-100 μm, and the grammage is 50-300 g/m ³ .

The parameters of the electrostatic spray technology in the step (4) are: the voltage of the high voltage generator is 40-80KV, and the distance from the spray nozzle to the receiving base cloth is 18-25cm, and the diameter of the spray nozzle is 0.05-0.2cm. The flow rate of the electrospinning liquid is 0.2-1.0mL/h, and the receiving time is 5-30min.

In the step (5) hot-pressing composite process, the hot-pressing temperature is 60-130° C., the pressure is 0.5-2 MPa, and the hot-pressing speed is 50-300 r/min.

A kind of nanofiber composite vehicle-mounted air filter paper prepared by the above-mentioned method, comprising superfine nanofiber web, nanofiber membrane and filter paper arranged successively, the fiber average diameter in the ultrafine nanofiber web is 20-35nm, and the fiber average diameter in the nanofiber is 200-300nm. Preferably, the porosity of the vehicle-mounted air filter paper is 0.25-0.85 cm ³ /g

Beneficial effects of the present invention: the prepared nanofiber composite vehicle air filter paper has a gradient structure, and the fiber diameter distribution is about 20-300nm, and has the advantages of fine diameter, small pore size, high strength, and good filtering effect. The nanofiber composite car air filter paper can achieve an initial filtration efficiency of 99.9% for PM _0.3 particles under the industrial standard wind speed (5.33cm/s), meeting the H12 standard for air filter materials. More importantly, in the self-cleaning backflushing test, compared with ordinary nanofiber filter materials (filtering efficiency drops by more than 50%), the present invention can still maintain the filtration efficiency of PM0.3 after 10,000 backflushing tests More than 90%, showing the strong composite strength between layers of composite filter paper and high filtration efficiency.

The prepared nanofiber membrane with gradient structure is coated on the cellulose filter paper and bonded by hot pressing. Relying on the good mechanical properties of the cellulose filter paper itself and the high surface energy of the nanofibers, the car air filter paper is oil-resistant, wear-resistant, High hardness, good elasticity, low resistance, high efficiency, high filtration accuracy, long life, etc., and the combination of electrostatic spinning and electrostatic spraying has the advantages of energy saving, simple process, convenient operation, and mass production. It provides convenient conditions for effectively improving the intake air quality of the engine and improving fuel efficiency.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Figure 1 is an electron microscope picture of a nanofiber composite vehicle air filter paper with a gradient structure.

Fig. 2 is a physical picture of the nanofiber composite vehicle air filter paper with gradient structure.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

A preparation method of a nanofiber composite vehicle-mounted air filter paper with a gradient structure, comprising the following steps:

1) Pour 1.2g of PS into different beakers and place in an oven at a temperature of 75°C for 2 hours. Then weigh 18 g of (N,N dimethylacetamide) DMAc into the bottle containing the corresponding PS and stir with a magnetic stirrer. The stirring temperature is 60°C, the rotational speed is 500r/min, and the stirring time is 4h.

2) Add 0.4 g of ethyl acrylate adhesive to the solution obtained in step 1), place it on a magnetic stirrer for stirring, the stirring temperature is 55° C., the stirring speed is 350 r/min, and the stirring time is 2 hours.

3) Put the reaction product obtained in step 2) at room temperature, add 0.02g of polyether ZT-143 curing agent, and place it on a magnetic stirrer for stirring. The stirring temperature is 25°C, the stirring speed is 50r/min, and the stirring time is 30min.

4) Pour 0.8g of PVDF into different beakers and place in an oven at a temperature of 75°C for 2 hours.

5) Weigh 0.1 g of triethylamine hydrochloride crystals into a clean glass bottle, then weigh 18 g of (N,N dimethylacetamide) DMAc into the corresponding bottle and stir with a magnetic stirrer. In order to ensure that the triethylamine hydrochloride crystals are fully dissolved, the stirring temperature is 70°C, the rotation speed is 500r/min, and the stirring time is 4h.

6) Then add the raw material in step 4) to the triethylamine hydrochloride/DMAc solution obtained in step 5), place it on a magnetic stirrer for stirring, the stirring temperature is 80°C, the stirring speed is 300r/min, and the stirring time is 8h.

7) Add 0.4 g of ethyl acrylate adhesive to the solution obtained in step 6), place it on a magnetic stirrer for stirring, the stirring temperature is 40° C., the stirring speed is 200 r/min, and the stirring time is 2 hours.

8) Place the reaction product obtained in step 7) at room temperature, add 0.01g of polyether ZT-143 curing agent, and place it on a magnetic stirrer for stirring. The stirring temperature is 20°C, the stirring speed is 50r/min, and the stirring time is 10min.

9) The solution obtained in step 3) is spun by electrospinning technology, and the PS nanofibers are sprayed onto the randomly arranged cellulose filter paper. Irregular cellulose filter paper is made from wood pulp through papermaking technology, with a pore size distribution of 75 μm. Wherein when the electrospinning device is working, the voltage of the high voltage generator is 50KV; the distance from the nozzle to the receiving base cloth is 20cm; the nozzle diameter is 0.15cm; the flow rate of the ejected electrospinning liquid is 1.5mL/h; the receiving time 30min.

10) The solution obtained in step 8) is spun by electrostatic spray technology, and the ultrafine PVDF nanofiber web is sprayed onto the filter paper prepared in step 9). Wherein when the electrostatic spray device is working, the voltage of the high voltage generator is 80KV; the distance from the spray nozzle to the receiving base cloth is 20cm; the diameter of the spray nozzle is 0.2cm; the flow rate of the sprayed electrospinning solution is 0.5mL/h; After 5 minutes, a multi-layer composite filter paper was prepared.

11) The multi-layer composite filter paper obtained in step 10) is tightly bonded together through hot-pressing compounding. In the hot-pressing compounding, the hot-pressing temperature is 80°C, the hot-pressing pressure is 1MPa, and the hot-pressing speed is 300r/min to obtain a nanofiber composite filter paper. Vehicle air filter paper, as shown in Figure 2.

It can be seen from Figure 1 that the obtained PS nanofibers have a diameter of 280nm, the average diameter of the PVDF ultrafine nanofiber web is 30nm, and the porosity of the nanofiber composite vehicle air filter paper is 0.68cm ³ /g. Then, the TSI8130A filter material testing system was used to test the efficiency performance of the nanofiber composite vehicle air filter paper prepared above. The filter medium was 0.3 μm NaCl aerosol, the air flow rate was 32 L/min, and the wind speed was 5.33 cm/s. After testing, the initial filtration efficiency of nanofiber composite car air filter paper for PM _0.3 particles can reach 99.9%, which meets the H12 standard of air filter materials. In the self-cleaning backflush test, the PM _0.3 filtration efficiency is 91% after 10000 backflush tests.

Example 2

A preparation method of a nanofiber composite vehicle-mounted air filter paper with a gradient structure, comprising the following steps:

1) Pour 0.9g of PAN into different beakers and place in an oven at a temperature of 50°C for 2 hours. Then weigh 18.8 g of (N,N dimethylacetamide) DMAc into the bottle containing the corresponding PAN and stir with a magnetic stirrer. The stirring temperature is 60°C, the rotational speed is 500r/min, and the stirring time is 4h.

2) Add 0.4 g of ethyl acrylate adhesive to the solution obtained in step 1), place it on a magnetic stirrer for stirring, the stirring temperature is 55° C., the stirring speed is 2000 r/min, and the stirring time is 4 hours.

3) Put the reaction product obtained in step 2) at room temperature, add 0.02g of polyether ZT-143 curing agent, and place it on a magnetic stirrer for stirring. The stirring temperature is 20°C, the stirring speed is 100r/min, and the stirring time is 20min.

4) Pour 0.9g of PU into different beakers and place in an oven at a temperature of 60°C for 2 hours.

5) Weigh 0.15g of triethylamine hydrochloride crystals into a clean glass bottle, then weigh 18.8g of (N,N dimethylacetamide) DMAc into the corresponding bottle and stir with a magnetic stirrer. In order to ensure that the triethylamine hydrochloride crystals are fully dissolved, the stirring temperature is 70°C, the rotation speed is 600r/min, and the stirring time is 4h.

6) Then add the raw materials in step 4) to the obtained triethylamine hydrochloride/DMAc solution, place it on a magnetic stirrer to stir, the stirring temperature is 90°C, the stirring speed is 400r/min, and the stirring time is 9h.

7) Add 0.3 g of ethyl acrylate adhesive to the solution obtained in step 6), place it on a magnetic stirrer for stirring, the stirring temperature is 55° C., the stirring speed is 250 r/min, and the stirring time is 4 hours.

8) Place the reaction product obtained in step 7) at room temperature, add 0.05g of polyether ZT-143 curing agent, and place it on a magnetic stirrer for stirring. The stirring temperature is 25°C, the stirring speed is 100r/min, and the stirring time is 10min.

9) The solution obtained in step 3) is spun by electrospinning technology, and the PAN nanofibers are sprayed onto the randomly arranged cellulose filter paper. Irregular cellulose filter paper is made of wood pulp through papermaking technology, with a pore size of 75 μm. Wherein when the electrospinning device is working, the voltage of the high voltage generator is 60KV; the distance from the nozzle to the receiving base cloth is 16cm; the nozzle diameter is 0.2cm; the flow rate of the ejected electrospinning liquid is 0.6mL/h; the receiving time 10min.

10) The solution obtained in step 8) is spun by electrostatic spray technology, and the ultrafine PU nanofiber web is sprayed onto the filter paper prepared in step 9). Wherein when the electrostatic spraying device was working, the voltage of the high voltage generator was 50KV; the distance from the spray nozzle to the receiving base cloth was 18cm; the diameter of the spray nozzle was 0.2cm; the flow rate of the sprayed electrospinning solution was 0.8mL/h; After 15 minutes, a multi-layer composite filter paper was prepared.

11) The multi-layer composite filter paper obtained in step 10) is tightly bonded together by hot-pressing. The hot-pressing temperature is 80° C., the hot-pressing pressure is 0.5 MPa, and the hot-pressing speed is 100 r/min to prepare nanofiber composite vehicle air filter paper.

After testing, the average diameter of the obtained PAN nanofiber is 202nm, the average diameter of the PU ultrafine nanofiber net is 21nm, and the porosity of the nanofiber composite vehicle air filter paper is 0.52cm ³ /g.

Example 3

A preparation method of a nanofiber composite vehicle-mounted air filter paper with a gradient structure, comprising the following steps:

1) Pour 0.9g PS into different beakers and place in an oven at 60°C for 2 hours. Then weigh 18.8 g of (N,N dimethylacetamide) DMAc into the bottle containing the corresponding PS and stir with a magnetic stirrer. The stirring temperature is 70°C, the rotating speed is 500r/min, and the stirring time is 4h.

2) Add 0.4 g of ethyl acrylate adhesive to the solution obtained in step 1), place it on a magnetic stirrer and stir at a stirring temperature of 50° C., a stirring speed of 300 r/min, and a stirring time of 4 hours.

3) Put the reaction product obtained in step 2) at room temperature, add 0.05g of polyether ZT-143 curing agent, and place it on a magnetic stirrer for stirring. The stirring temperature is 22°C, the stirring speed is 60r/min, and the stirring time is 10min.

4) Pour 0.9g of PVDF into different beakers and place in an oven at a temperature of 55°C for 2 hours.

5) Weigh 0.25g of triethylamine hydrochloride crystals into a clean glass bottle, then weigh 18.8g of (N,N dimethylacetamide) DMAc into the corresponding bottle and stir with a magnetic stirrer. In order to ensure that the triethylamine hydrochloride crystals are fully dissolved, the stirring temperature is 70°C, the rotational speed is 500r/min, and the stirring time is 4h.

6) Then add the raw materials in step 4) to the obtained triethylamine hydrochloride/DMAc solution, place it on a magnetic stirrer to stir, the stirring temperature is 100°C, the stirring speed is 400r/min, and the stirring time is 10h.

7) Add 0.4 g of ethyl acrylate adhesive to the solution obtained in step 6), place it on a magnetic stirrer for stirring, the stirring temperature is 55° C., the stirring speed is 300 r/min, and the stirring time is 4 hours.

8) Put the reaction product obtained in step 7) at room temperature, add 0.02g of polyether ZT-143 curing agent, and place it on a magnetic stirrer for stirring. The stirring temperature is 20°C, the stirring speed is 100r/min, and the stirring time is 10min.

9) The solution obtained in step 3) is spun by electrospinning technology, and the PS nanofibers are sprayed onto the randomly arranged cellulose filter paper. Irregular cellulose filter paper is made from wood pulp through papermaking technology, with a pore size distribution of 100 μm. Wherein when the electrospinning device is working, the voltage of the high voltage generator is 50KV; the distance from the nozzle to the receiving base cloth is 16cm; the nozzle diameter is 0.3cm; the flow rate of the ejected electrospinning liquid is 0.8mL/h; the receiving time 10min.

10) The solution obtained in step 8) is spun by electrostatic spray technology, and the ultrafine PVDF nanofiber web is sprayed onto the nanofiber layer prepared in step 9). Wherein when the electrostatic spray device was working, the voltage of the high voltage generator was 60KV; the distance from the spray nozzle to the receiving base cloth was 16cm; the diameter of the spray nozzle was 0.1cm; the flow rate of the sprayed electrospinning solution was 0.5mL/h; After 10 minutes, a multi-layer composite filter paper was prepared.

11) The multi-layer composite filter paper obtained in step 10) is tightly bonded together through hot pressing. The hot-pressing temperature is 70° C., the hot-pressing pressure is 2 MPa, and the hot-pressing speed is 100 r/min, and the nanofiber composite vehicle air filter paper is prepared.

After testing, the diameter of the obtained PS nanofibers is 200-300nm, the diameter distribution of the PVDF ultrafine nanofiber net is 20-35nm respectively, and the porosity of the nanofiber composite vehicle air filter paper is 0.61cm ³ /g.

Example 4

A preparation method of a nanofiber composite vehicle-mounted air filter paper with a gradient structure, comprising the following steps:

1) Pour 0.9g of PS into different beakers and place in an oven at a temperature of 60°C for 3 hours. Then weigh 18.8 g of (N,N dimethylacetamide) DMAc into the bottle containing the corresponding PS and stir with a magnetic stirrer. The stirring temperature is 70°C, the rotational speed is 500r/min, and the stirring time is 4h.

2) Add 0.3 g of ethyl acrylate adhesive to the solution obtained in step 1), place it on a magnetic stirrer for stirring, the stirring temperature is 45° C., the stirring speed is 350 r/min, and the stirring time is 4 hours.

3) Put the reaction product obtained in step 2) at room temperature, add 0.03g of polyether ZT-143 curing agent, and place it on a magnetic stirrer for stirring. The stirring temperature is 20°C, the stirring speed is 40r/min, and the stirring time is 10min.

4) Pour 0.9g of PU into different beakers and place in an oven at a temperature of 75°C for 2 hours.

5) Weigh 0.2g of triethylamine hydrochloride crystals into a clean glass bottle, then weigh 19.2g of (N,N dimethylacetamide) DMAc into the corresponding bottle and stir with a magnetic stirrer. In order to ensure that the triethylamine hydrochloride crystals are fully dissolved, the stirring temperature is 60°C, the rotating speed is 600r/min, and the stirring time is 4h.

6) Then add the raw material in step 4) to the obtained triethylamine hydrochloride/DMAc solution, place it on a magnetic stirrer to stir, the stirring temperature is 80°C, the stirring speed is 500r/min, and the stirring time is 10h.

7) Add 0.3 g of ethyl acrylate adhesive to the solution obtained in step 6), place it on a magnetic stirrer for stirring, the stirring temperature is 45° C., the stirring speed is 200 r/min, and the stirring time is 4 hours.

8) Place the reaction product obtained in step 7) at room temperature, add 0.01g of polyether ZT-143 curing agent, and place it on a magnetic stirrer for stirring. The stirring temperature is 20°C, the stirring speed is 50r/min, and the stirring time is 10min.

9) The reaction product obtained in step 3) is sprayed onto the randomly arranged cellulose filter paper by electrospinning technology. Irregular cellulose filter paper is made from wood pulp through papermaking technology, with a pore size distribution of 75 μm. Wherein when the electrospinning device is working, the voltage of the high voltage generator is 40KV; the distance from the nozzle to the receiving base cloth is 16cm; the nozzle diameter is 0.5cm; the flow rate of the ejected electrospinning liquid is 0.8mL/h; the receiving time 10min.

10) The reaction product obtained in step 8) is sprayed onto the cellulose filter paper containing the random arrangement of step 9) by using the electrostatic spraying technique. Wherein when the electrostatic spray device is working, the voltage of the high voltage generator is 60KV; the distance from the spray nozzle to the receiving base cloth is 20cm; the diameter of the spray nozzle is 0.2cm; the flow rate of the sprayed electrospinning solution is 0.5mL/h; After 15 minutes, a multi-layer composite filter paper was prepared.

11) The multi-layer composite filter paper obtained in step 10) is tightly bonded together by hot-pressing. The hot-pressing temperature is 60° C., the hot-pressing pressure is 1 MPa, and the hot-pressing speed is 50 r/min to prepare the nanofiber composite vehicle air filter paper.

After testing, the obtained PS nanofibers have a diameter of 200-300nm, the diameter distribution of the PU ultrafine nanofiber net is 20-35nm respectively, and the porosity of the nanofiber composite vehicle air filter paper is 0.71cm ³ /g.

Example 5

A preparation method of a nanofiber composite vehicle-mounted air filter paper with a gradient structure, comprising the following steps:

1) Pour 1g of PAN into different beakers and place in an oven at a temperature of 50°C for 5 hours. Then weigh 25g of (N,N dimethylformamide) DMF into the bottle containing the corresponding PAN and stir with a magnetic stirrer. The stirring temperature is 65°C, the rotating speed is 500r/min, and the stirring time is 4h.

2) Add 0.2 g of ethyl acrylate adhesive to the solution obtained in step 1), place it on a magnetic stirrer for stirring, the stirring temperature is 40° C., the stirring speed is 2000 r/min, and the stirring time is 2 hours.

3) Put the reaction product obtained in step 2) at room temperature, add 0.01g of polyether ZT-143 curing agent, and place it on a magnetic stirrer for stirring. The stirring temperature is 23°C, the stirring speed is 100r/min, and the stirring time is 20min.

4) Pour 1g of PU into different beakers and place in an oven at a temperature of 60°C for 4 hours.

5) Weigh 0.2g of triethylamine sulfate crystals into a clean glass bottle, then weigh 25g of (N,N dimethylacetamide) DMAc into the corresponding bottle and stir with a magnetic stirrer. In order to ensure that the triethylamine hydrochloride crystals are fully dissolved, the stirring temperature is 65°C, the rotational speed is 600r/min, and the stirring time is 4h.

6) Then add the raw material in step 4) to the obtained triethylamine hydrochloride/DMAc solution, place it on a magnetic stirrer to stir, the stirring temperature is 120°C, the stirring speed is 400r/min, and the stirring time is 6h.

7) Add 0.2 g of ethyl acrylate adhesive to the solution obtained in step 6), place it on a magnetic stirrer for stirring, the stirring temperature is 45° C., the stirring speed is 250 r/min, and the stirring time is 3 hours.

8) Put the reaction product obtained in step 7) at room temperature, add 0.01g of polyether ZT-143 curing agent, and place it on a magnetic stirrer for stirring. The stirring temperature is 25°C, the stirring speed is 100r/min, and the stirring time is 30min.

9) The solution obtained in step 3) is spun by electrospinning technology, and the PAN nanofibers are sprayed onto the randomly arranged cellulose filter paper. Irregular cellulose filter paper is made of wood pulp through papermaking technology, with a pore size of 75 μm. Wherein when the electrospinning device is working, the voltage of the high voltage generator is 10KV; the distance from the nozzle to the receiving base cloth is 15cm; the nozzle diameter is 0.15cm; the flow rate of the ejected electrospinning liquid is 0.5mL/h; the receiving time 30min.

10) The solution obtained in step 8) is spun by electrostatic spray technology, and the ultrafine PU nanofiber web is sprayed onto the filter paper prepared in step 9). Wherein when the electrostatic spray device is working, the voltage of the high voltage generator is 40KV; the distance from the spray nozzle to the receiving base cloth is 25cm; the diameter of the spray nozzle is 0.05cm; the flow rate of the sprayed electrospinning solution is 0.1mL/h; The time is 20min, and the multi-layer composite filter paper is prepared.

11) The multi-layer composite filter paper obtained in step 10) is tightly bonded together by hot-pressing, the hot-pressing temperature is 130°C, the hot-pressing pressure is 0.1MPa, and the hot-pressing speed is 50r/min, and the nanofiber composite vehicle air filter paper is obtained. filter paper.

After testing, the average diameter of the obtained PAN nanofiber is 290nm, the average diameter of the PU ultrafine nanofiber net is 34nm, and the porosity of the nanofiber composite vehicle air filter paper is 0.26cm ³ /g.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (10)

1. a preparation method of nanofiber composite vehicle-mounted air filter paper with gradient structure, is characterized in that, comprises the following steps: (1) Stirring and dissolving the polymer I, the adhesive and the curing agent in sequence in the solvent I to prepare a nanofiber spinning solution; (2) stirring and dissolving triethylamine salt, polymer II, adhesive and curing agent into solvent II in sequence to prepare ultrafine nanofiber spinning solution; (3) The nanofiber spinning solution prepared in step (1) is spun by electrospinning technology, and a layer of nanofiber membrane is sprayed on the filter paper to obtain a nanofiber membrane filter paper; (4) The ultrafine nanofiber spinning solution prepared in step (2) is spun by electrostatic spray technology, and a layer of ultrafine nanofiber web is sprayed on the nanofiber membrane filter paper prepared in step (3) to obtain Multilayer Composite Filter Paper (5) bonding each layer of the multilayer composite filter paper prepared in step (4) together through a hot-press composite process to obtain a nanofiber composite vehicle-mounted air filter paper. 2. according to the preparation method of the nanofiber composite car air filter paper with gradient structure described in claim 1, it is characterized in that: in the described step (1), the mass ratio of adhesive and polymer I is 1: (2-5), The mass ratio of curing agent to polymer I is 1:(10-100), and the mass ratio of solvent I to polymer I is (12-25):1. 3. according to the preparation method of the nanofiber composite vehicle-mounted air filter paper with gradient structure described in claim 2, it is characterized in that: in the described step (2), the mass ratio of triethylamine salt and polymer II is 1: (5- 8), the mass ratio of adhesive to polymer II is 1:(2-5), the mass ratio of curing agent to polymer II is 1:(10-100), and the mass ratio of solvent II to polymer II is (12 -25):1. 4. The preparation method of the nanofiber composite vehicle-mounted air filter paper with gradient structure according to claim 3, characterized in that: the polymer I is polystyrene or polyacrylonitrile; the solvent I is N, N dimethyl Acetamide or N,N dimethylformamide; the polymer II is polyvinylidene fluoride or polyurethane; solvent II is N,N dimethylacetamide or N,N dimethylformamide; the steps In (1) or (2), the adhesive is ethyl acrylate, and the curing agent is polyetheramine; the triethylamine salt is triethylamine hydrochloride, triethylamine sulfate or triethylamine nitrate wherein Any one or a combination of two or more. 5. according to the preparation method of the nanofiber composite vehicle-mounted air filter paper with gradient structure described in claim 4, it is characterized in that, the stirring and dissolving conditions of each component in the described step (1) are as follows: the stirring and dissolving temperature of polymer I is 60-70°C; the stirring and dissolving temperature of the adhesive is 40-55°C; the stirring and dissolving temperature of the curing agent is 20-25°C, and the stirring time is 10-30min. 6. according to the preparation method of the nanofiber composite vehicle-mounted air filter paper with gradient structure according to claim 4, it is characterized in that, the stirring and dissolving conditions of each component in the described step (2) are as follows: the stirring and dissolving temperature of triethylamine salt 60-70℃; the stirring and dissolving temperature of polymer II is 80-120℃; the stirring and dissolving temperature of adhesive is 40-55℃; the stirring and dissolving temperature of curing agent is 20-25℃, and the stirring time is 10-30min. 7. according to the preparation method of the nanofiber composite vehicle-mounted air filter paper with gradient structure described in claim 6, it is characterized in that, the parameter of electrospinning technology is in the described step (3): the spinning voltage of high voltage generator is 10 -80KV, the distance from the nozzle to the receiving base cloth is 15-20cm, the nozzle diameter is 0.15-0.3cm, the flow rate of the sprayed electrospinning liquid is 0.5-1.5mL/h, and the receiving time is 5-30min; the filter paper for cellulose filter paper. 8. according to the preparation method of the nanofiber composite vehicle-mounted air filter paper with gradient structure described in claim 7, it is characterized in that, the parameter of electrostatic spray technology is in the described step (4): the voltage of high voltage generator is 40-80KV, The distance from the spray nozzle to the receiving base cloth is 18-25cm, the diameter of the spray nozzle is 0.05-0.2cm, the flow rate of the sprayed electrospinning solution is 0.2-1.0mL/h, and the receiving time is 5-30min. 9. The preparation method of the nanofiber composite vehicle-mounted air filter paper with gradient structure according to claim 8, characterized in that: in the step (5) hot-pressing composite process, the hot-pressing temperature is 60-130 ° C, and the hot-pressing pressure is 0.5- 2MPa, hot pressing speed 50-300r/min. 10. The nanofiber composite vehicle-mounted air filter paper with gradient structure prepared by the method described in any one of claims 1-9, is characterized in that, comprises superfine nanofiber web, nanofiber membrane and filter paper that are arranged in sequence, superfine nanofiber The average diameter of fibers in the net is 20-35nm, and the average diameter of fibers in the nanofiber film is 200-300nm.

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