Preparation method of microporous fiber and microporous fiber cloth

Abstract

The invention relates to a preparation method of microporous fibers and microporous fiber cloth, and the method comprises the following steps: step 1, downwards spraying molten master batches through a spinneret plate, and forming a non-surface-dry fiber area by the sprayed fiber; 2, a catalytic material is sprayed to the non-surface-dry area of the cellosilk, the catalytic material is attached to the cellosilk through the surface viscosity of the fiber, and microporous fiber of a nano-microporous structure is formed; the fiber cloth produced by the microporous fiber prepared by the preparation method of the microporous fiber is prepared in a non-woven fabric processing mode or in a weaving mode; according to the technology, the nano catalytic material is creatively combined with the fiber of the fiber cloth; through the technical processing flow, the catalytic material is finally embedded in the fiber surface to promote the formation of a nano-porous structure on the fiber surface; the nano porous structure obviously improves the filtering efficiency of the fiber cloth on liquid and gas, and greatly expands the application prospect of the fiber cloth in the fields of medical treatment and public health, air purification, liquid filtration and the like.

Description

Technical Field

[0001] This invention relates to the field of fiber manufacturing technology, specifically to a method for forming a nanoporous structure by spraying a catalytic material onto the surface of fibers during the uncured stage, and the microporous fiber cloth obtained by this method. Background Technology

[0002] Textile manufacturing involves the diverse types of fiber fabrics, such as nonwoven fabrics and woven fabrics, all made from short or long fibers. The development of nanoporous fibers and related processing technologies is a key research focus, aiming to endow fiber fabric materials with unique properties to meet diverse application needs. Traditional microporous fibers primarily form pores through physical etching or chemical solvent treatment, which suffers from complex processes, significant environmental pollution, and uneven pore size. This invention involves spraying MnCoO2 onto the un-dried areas of the fiber during the melt spinning stage. x Composite catalytic materials utilize the principle of surface adhesion to form nanopores. Summary of the Invention

[0003] In order to solve the technical problems existing in the prior art, the purpose of this invention is to provide a method for preparing microporous fibers and microporous fiber cloth, which is an innovative processing technology that can form nanopores on the material fibers of the fiber cloth, aiming to endow the fiber cloth material with unique properties and meet special application requirements.

[0004] To achieve the above objectives, the technical solution adopted by this invention is: a method for preparing microporous fibers, comprising the following steps:

[0005] Step 1: The molten masterbatch is spun downwards through a spinneret, and the spun fibers form areas of undried fibers.

[0006] Step 2: Spray catalytic material onto the undried areas of the fiber filaments, using the surface viscosity of the fiber to make the catalytic material adhere to the fiber filaments, forming microporous fibers with a nanoporous structure;

[0007] Furthermore, the masterbatch mentioned in step one is a plastic masterbatch with a melting temperature of 220-280℃. The heating temperature is determined according to the selection of the masterbatch material, so that it is in a high-temperature molten state.

[0008] Furthermore, the plastic masterbatch used is selected from at least one of polypropylene (PP), polyethylene terephthalate (PET), and polystyrene (PS).

[0009] Furthermore, the undried area of ​​the fiber filaments mentioned in step two refers to the area within 25 cm extending downwards from the spinneret nozzle of the fiber filaments.

[0010] Furthermore, in step two, the catalytic material is sprayed using a powder spraying device, which is positioned 15-20 cm away from the spinneret. The powder spraying device sprays the catalytic material onto the undried fibers sprayed from the spinneret.

[0011] Furthermore, the powder spraying device is arranged in a row of several powder spraying guns on one side directly below the spinneret nozzle, with the nozzles of the powder spraying guns facing the fibers ejected from the spinneret nozzle; the powder spraying direction of the powder spraying guns is perpendicular to the fiber exit direction ejected from the spinneret.

[0012] Furthermore, the powder spraying device has several powder spraying guns evenly distributed and the distance between each pair of adjacent powder spraying guns is set at 10 cm; the distance between the powder spraying gun nozzle and the corresponding horizontal height of the spinneret is set at 10-15 cm, and the air pressure is maintained at 0.4-0.6 Pa during powder spraying.

[0013] Furthermore, step two also includes a catalytic material recovery step, in which free catalytic material is adsorbed by a negative pressure air mechanism;

[0014] Furthermore, the negative pressure air mechanism includes a powder collection bag and a powder collection pump. The powder collection pump is connected to the powder collection bag through a pipe. The negative pressure air generated by the negative pressure air mechanism can effectively adsorb and recover the free catalytic material and collect the catalytic material into the powder collection bag.

[0015] Furthermore, the catalyst material is a MnCoOx composite catalyst material, which is made into nano-spherical particles from manganese salt, cobalt salt, oxalate and deionized water;

[0016] The MnCoOx composite catalytic material is prepared by optimized coupling of manganese and cobalt dual centers. First, a manganese-cobalt precursor salt solution is obtained, followed by a manganese-cobalt salt precipitate. This precipitate is then separated by centrifugation, and the solid product is dried to produce nanospheres with a particle size of 100 nm. The preparation steps of this catalytic material are as follows:

[0017] a. Dissolve a certain amount of manganese salt and cobalt salt in deionized water and stir at room temperature to obtain a manganese-cobalt precursor salt solution;

[0018] b. Dissolve oxalate in deionized water and add it to the manganese-cobalt precursor salt solution obtained in a above. Stir vigorously at a certain temperature for a certain time to obtain manganese-cobalt salt precipitate;

[0019] c. Centrifuge the precipitate obtained in step b above, wash it repeatedly with deionized water until the washing liquid is clear, and dry the solid product to obtain the MnCoOx composite catalyst material.

[0020] The manganese salt and cobalt salt are potassium permanganate and cobalt nitrate, and the molar ratio of manganese salt to cobalt salt is 1:1 to 5.

[0021] The oxalate is ammonium oxalate monohydrate, and the molar ratio of manganese salt to oxalate is 1–5:1; the volume ratio of the manganese-cobalt precursor salt solution in step a to the oxalate solution in step b is 0.5–3:1; the temperature and stirring time in step b are 70–100℃ and 8–12 h, respectively. The microporous fiber fabric produced by the above-described method is manufactured through nonwoven fabric processing or by weaving.

[0022] The nonwoven fabric produced by the nonwoven fabric processing method is a nanoporous structure formed by MnCoOx composite catalytic material adhering to the surface of the fiber itself. This production method can produce spunbond nonwoven fabric, hot air nonwoven fabric or meltblown nonwoven fabric to meet the needs of different scenarios for nonwoven fabric.

[0023] Compared with the prior art, the technical effects of the present invention are reflected in:

[0024] Employing an innovative material combination method: This technology creatively combines nanocatalytic materials with fiber cloth, opening up a completely new method for material surface modification;

[0025] Using this technology, spunbond nonwoven fabrics, hot air nonwoven fabrics, and meltblown nonwoven fabrics can be produced to meet the needs of different scenarios for nonwoven fabrics.

[0026] Through this processing technology, the catalytic material is finally embedded in the fiber surface, causing the fiber surface to form a nanoporous structure. This nanoporous structure significantly improves the filtration efficiency of the fiber cloth for liquids and gases, enhances its adsorption performance, and greatly expands the application prospects of the fiber cloth in the fields of medical and health care, air purification and liquid filtration.

[0027] This microporous fiber preparation method also features an efficient catalytic material recovery and purification mechanism: free catalytic materials are recovered through negative pressure air during the production process; a water washing process is also included in the nonwoven fabric preparation process using fibers obtained by this method to ensure full utilization of materials and product purity; this microporous fiber preparation method also demonstrates broad material applicability: it supports various types of plastic masterbatches, which provide a rich material selection basis for creating nonwoven fabrics with nanoporous structures and can produce various types of nonwoven fabrics, greatly expanding the application scope of the technology. Attached Figure Description

[0028] Figure 1 This is a process flow diagram of a specific embodiment of the production of fiber cloth according to the present invention.

[0029] Figure 2 for Figure 1 A structural diagram of the production equipment used in the production process of medium-density fiber cloth.

[0030] Figure 3 for Figure 2 Side view.

[0031] Figure 4 This is a schematic diagram of the spinneret structure of the production equipment of the present invention.

[0032] Figure 5 MnCoO2 is used in the preparation method of microporous fibers of this invention. x -I. SEM image of the composite catalytic material.

[0033] Figure 6 The water resistance test of the catalyst materials in Example 2 and Comparative Example 1 (MnCoO) x -Ⅱ and MnO2-I represent the catalytic materials prepared in Example 2 and Comparative Example 1, respectively.

[0034] In the diagram, 1. Spinneret, 1.1. Spinneret nozzle, 2. Fiber filament, 3. Powder spray gun nozzle, 4. Powder collection bag, 5. Powder collection pump, 6. Track. Detailed Implementation

[0035] The technical solution of the present invention will be further defined below with reference to the accompanying drawings and specific embodiments, but the scope of protection is not limited to the description.

[0036] Example 1

[0037] like Figure 1-6 The method for preparing the microporous fibers shown includes the following steps:

[0038] Step 1: Heat the PET masterbatch to 220℃ to melt it, and then spin it downwards through a spinneret; the spun fibers 2 form an undried area;

[0039] Step 2: Spray catalytic material onto the undried area of ​​fiber 2, using the surface viscosity of the fiber to make the catalytic material adhere to the fiber 2, forming a microporous fiber with a nanoporous structure; the undried area of ​​fiber 2 refers to the area within 25 cm downward from the spinneret 1.1 of the spinneret 1; the fiber 2 in this area is in the optimal viscosity state, and the fiber surface has a large viscosity.

[0040] In step two, the catalytic material is sprayed onto the undried area of ​​the fibers 2 ejected from the spinneret 1 using a powder spraying device positioned 20 cm away from one side of the spinneret 1. The powder spraying device consists of several powder spraying guns arranged in a row on one side directly below the spinneret nozzle 1.1 of the spinneret 1, with the nozzles 3 facing the fibers 2 ejected from the nozzle 1.1. It should be noted that the entire powder spraying device is located diagonally below the spinneret 1 and is not radially coaxial with it. The powder spraying direction of the guns is perpendicular to the fiber exit direction of the fibers 2 ejected from the spinneret 1. The powder spraying guns are evenly distributed, with a spacing of 10 cm between each adjacent gun. The distance between the nozzle 3 and the corresponding horizontal height of the nozzle 1.1 is also 10 cm, and the air pressure is maintained at 0.5 Pa during spraying.

[0041] In step two, during the spraying process of the catalyst material, the catalyst material is recovered by using a negative pressure mechanism installed in the production equipment to recover the free catalyst material; the negative pressure recovery device (powder collection pump pressure -5kPa) recovers the unattached catalyst material.

[0042] The negative pressure air mechanism includes a powder collection bag 4 and a powder collection pump 5. The powder collection pump 5 is connected to the powder collection bag 4 through a pipe. The negative pressure air generated by the negative pressure air mechanism can effectively adsorb and recover the free catalytic material and collect the catalytic material into the powder collection bag 4. This avoids material waste and reduces pollution to the production environment.

[0043] The catalyst is MnCoO x -Ⅰ Composite catalytic material, MnCoO x The MnCoOx composite catalytic material was prepared via a redox method. The specific steps were as follows: 5g of potassium permanganate and 5g of cobalt nitrate hexahydrate were dissolved in 100mL of deionized water, and then 5g of ammonium oxalate monohydrate was dissolved in 50mL of deionized water. The two solutions were then rapidly mixed together and stirred vigorously at 90℃ for 10 hours. The resulting MnCoOx precipitate was then washed repeatedly with deionized water until the washing liquid was clear. The solid product was then dried to obtain the MnCoOx composite catalytic material, named MnCoOx-I. Figure 5 As can be seen from the prepared MnCoO x The composite catalytic material exhibits an ultrathin needle-like morphology, and the needle-like nanoparticles further aggregate to form spherical particles with a particle size of approximately 100 nm.

[0044] In this embodiment, the microporous fiber fabric produced by the above-described method for preparing microporous fibers is manufactured through a nonwoven fabric processing method, taking the production of nonwoven fabric with fiber filaments as an example. The process of manufacturing through the nonwoven fabric processing method includes: fabric formation and hot pressing, water washing and purification, and drying and rolling.

[0045] The fabric formation and hot pressing process involves spraying fibers with adhesive catalyst material onto the traveling belt 6 of the production equipment, collecting them through the traveling belt 6 to form a nonwoven fabric; then, a hot pressing roller is used to perform a hot pressing treatment on the nonwoven fabric.

[0046] The water washing and purification process includes: the non-woven fabric after heat-pressing is put into a water tank, and the water tank is used to wash away the catalytic material that has not adhered to the fibers by vibration.

[0047] The drying and rolling process includes: the cleaned nonwoven fabric is put into a 30-50 meter drying oven for drying, the oven temperature is maintained at 80-85℃, and after drying, it is rolled out to produce a nonwoven fabric with a nanoporous structure on the fiber surface.

[0048] When hot pressing is performed using hot rollers, the pressure of the hot rollers is adjusted specifically according to the characteristics of different types of nonwoven fabrics such as spunbond nonwoven fabrics, hot-air nonwoven fabrics, and meltblown nonwoven fabrics. This promotes deeper embedding of the catalyst material into the fiber, improving product quality; MnCoO loaded... x Non-woven fabrics made of composite catalytic materials can carry out formaldehyde catalytic oxidation reaction at room temperature, decompose formaldehyde, and purify indoor air.

[0049] In this embodiment, an isolation cover is provided between the spinneret 1 and the traveling track 6 of the production equipment. The purpose of spraying and collecting the catalytic material inside the isolation cover is to prevent dust pollution.

[0050] Example 2

[0051] The microporous fiber fabric prepared by the method of the present invention is produced by processing nonwoven fabric. The difference from Example 1 is that, taking the production of short-fiber spunbond nonwoven fabric as an example, the fiber filaments are in the form of atomized filament bundles. The catalytic material spraying method in the microporous fiber preparation process and the processing steps in the nonwoven fabric preparation process are the same as in Example 1.

[0052] PP masterbatch is heated to 250℃ to melt and then spun into fibers.

[0053] The powder spray gun is 15 cm away from the spinneret nozzle, with a spacing of 10 cm, and sprays MnCoOx.

[0054] Using the same recycling and post-processing techniques as in Example 1, meltblown nonwoven fabric is produced.

[0055] The catalyst is MnCoO x -II composite catalytic material, MnCoO x-II composite catalytic material was prepared by a redox method. The specific operational details are as follows: First, 2.5g of potassium permanganate and 5g of cobalt nitrate hexahydrate were dissolved in 80mL of deionized water. Then, 2.3g of ammonium oxalate monohydrate was dissolved in 50mL of deionized water. The two fully dissolved solutions were then rapidly mixed together and stirred vigorously at 90℃ for 10h. The resulting MnCoO₂ was then... x The precipitate was washed repeatedly with deionized water until the washing liquid was clear, and then the solid product was dried to obtain MnCoO. x The composite catalytic material is named MnCoO x -Ⅱ.

[0056] As another embodiment of the same type as Examples 1 and 2, the microporous fiber cloth is produced by a nonwoven fabric processing method, and is also applicable to different types of nonwoven fabrics such as needle-punched nonwoven fabrics and spunlace nonwoven fabrics as technical implementations. Loaded MnCoO x Non-woven fabrics made of composite catalytic materials can carry out formaldehyde catalytic oxidation reaction at room temperature, decompose formaldehyde, and purify indoor air.

[0057] Example 3

[0058] The microporous fiber prepared by the method of the present invention is used to produce fiber cloth, which is made by weaving, and PS masterbatch is heated to 280°C to melt and spin into fibers; catalytic material is sprayed on.

[0059] The catalyst is MnCoO x -II composite catalytic material, MnCoO x -II I composite catalyst material was prepared by a redox method. The specific operational details are as follows: First, 2.5 g of potassium permanganate and 5 g of cobalt nitrate hexahydrate were dissolved in 80 mL of deionized water. Then, 4.6 g of ammonium oxalate monohydrate was dissolved in 50 mL of deionized water. The two fully dissolved solutions were rapidly mixed together and stirred vigorously at 90 °C for 10 h. Afterwards, the resulting MnCoO2 composite catalyst material was... x The precipitate was washed repeatedly with deionized water until the washing liquid was clear, and then the solid product was dried to obtain MnCoO. x The composite catalytic material is named MnCoOx-ⅡI.

[0060] Microporous fibers are woven into woven fabric and loaded with MnCoO x The woven fabric containing composite catalytic materials can carry out the catalytic oxidation reaction of formaldehyde at room temperature, decomposing formaldehyde and purifying indoor air.

[0061] Comparative Example 1

[0062] 2.5 g of potassium permanganate and 2.3 g of ammonium oxalate monohydrate were dissolved in 75 mL of deionized water. The two solutions were then rapidly mixed and stirred vigorously at 90 °C for 10 h. The resulting MnO2 precipitate was then washed repeatedly with deionized water until the washing liquid was clear. The solid product was then dried to obtain a single-active-component MnO2 catalytic material, named MnO2-I.

[0063] MnCoO in Examples 1, 2, and 3 respectively x -Ⅰ、MnCoO x -IⅠ、MnCoO x The composite catalyst I-II and the MnO2-I catalyst from Comparative Example 1 were packed into a self-made fixed-bed quartz reactor, and a mixed gas (100 ppm formaldehyde, 99.99% air) was introduced. The volume hourly space velocity was adjusted to 50,000, 80,000, 110,000, and 170,000 h⁻¹. -1 During the test, the temperature of the test system was maintained at a stable 25℃. Formaldehyde and carbon dioxide concentrations in the reaction exhaust gas were monitored in real time using a formaldehyde and carbon dioxide analyzer. Table 1 shows the test results after 30 minutes of reaction.

[0064] Table 1

[0065]

[0066] Table 1 shows the MnCoO₂ of Examples 1, 2, and 3. x Decomposition of formaldehyde at different space velocities at a catalytic concentration of 100 ppm using composite catalytic materials and the single-component MnO2 catalytic material of Comparative Example 1 (MnCoO x -Ⅰ、MnCoO x -IⅠ、MnCoO x -ⅠII and MnO2-Ⅰ represent the catalytic materials prepared in Examples 1, 2, 3 and Comparative Example 1, respectively;

[0067] As can be seen from Table 1, the MnCoO prepared in Examples 1-3 x The activity of the composite catalytic material is significantly better than that of the MnO2-Ⅰ catalytic material in Comparative Example 1. This means that the introduction of Co element effectively increases the oxygen vacancies in the catalytic material, thereby improving its reactivity. Furthermore, comparing the reactivity of the composite catalytic materials with the same Co and Mn content prepared in Examples 2 and 3, it is clear that the amount of ammonium oxalate as the reducing agent also affects the reactivity at the same Co and Mn content; increasing the amount of ammonium oxalate increases the activity of the composite catalytic material.

[0068] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A process for the preparation of microporous fibers, characterized in that, It comprises the following steps: Step one: melt the master batch through the spinneret downward, the fiber filament forms the area of the non-drying fiber filament; Step two: spray the catalytic material in the non-drying area of the fiber filament, use the fiber surface viscosity to make the catalytic material adhere to the surface of the fiber filament, form the microporous fiber with nano microporous structure.

2. The method of making microporous fibers according to claim 1, wherein: The non-drying area of the fiber filament in step two refers to the area within 25 cm of the fiber filament extending downward from the spinneret nozzle.

3. The method of making microporous fibers according to claim 1, wherein: The catalytic material is MnCoOx composite catalytic material, which is made into nanometer spherical particles by manganese salt, cobalt salt, oxalate and deionized water.

4. The method of making microporous fibers according to claim 3, wherein: The MnCoOx composite catalytic material is made by optimizing the coupling of manganese-cobalt double center, first getting manganese-cobalt precursor salt solution, then getting manganese-cobalt salt precipitate, and then making nanometer spherical particles by centrifugal separation, taking out the solid product and drying.

5. The method of claim 1, wherein: The master batch in step one is plastic master batch, and the melting temperature is 220-280℃; the plastic master batch selected is at least one of polypropylene, polyethylene terephthalate and polystyrene.

6. The method of making microporous fibers according to claim 1, wherein: The spraying of the catalytic material in step two is realized by the powder spraying device, which is arranged 15-20 cm away from the spinneret, and the powder spraying device sprays the non-drying fiber filament sprayed from the spinneret with catalytic material.

7. The method of claim 6, wherein: The powder spraying device is arranged on one side of the position directly below the spinneret nozzle of the spinneret in the form of a row of powder spraying guns, and the powder spraying gun nozzles are directed towards the fiber filament sprayed from the spinneret nozzle; the powder spraying direction of the powder spraying gun is perpendicular to the fiber filament spraying direction of the spinneret; the powder spraying guns of the powder spraying device are uniformly distributed, and the distance between every two adjacent powder spraying guns is set to 10 cm; the distance between the powder spraying gun nozzles and the corresponding horizontal height of the spinneret nozzle is set to 10-15 cm, and the air pressure during powder spraying is maintained at 0.4-0.6 Pa.

8. The method of claim 1, wherein: Step two also includes a catalytic material recycling step, which uses a negative pressure air mechanism to adsorb free catalytic material; the negative pressure air mechanism includes a powder collecting pump and a powder collecting bag, and the powder collecting pump is connected to the powder collecting bag through a pipeline.

9. A microporous fabric made of the microporous fabric obtained by the method according to any one of claims 1 to 8, characterized in that, It is obtained by the processing method of non-woven fabric.

10. A microporous fabric made of the microporous fabric obtained by the method according to any one of claims 1 to 8, characterized in that, It is obtained by the processing method of weaving.

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