Abrasion-resistant blended gradient needle punch filtration material and method of making

Abstract

The present application relates to the technical field of filter material preparation, and particularly relates to a wear-resistant blended gradient needle-punched filter material and a preparation method, which comprises the following steps: S1, preparing a first mixture and a second mixture; S2, respectively laying the first mixture and the second mixture to obtain an inner layer and an outer layer; S3, hooking and bonding the outer layer and the inner layer by pre-punching to obtain a base material; S4, vacuum impregnating the base material in an impregnation liquid for h; S5, treating the base material in step S4 at 80-120 DEG C for 15-30 min; S6, applying a finishing agent to the surface of the base material treated in step S5 by padding; S7, treating the base material treated in step S6 at 150-200 DEG C for 3-5 min; and S8, laying a PTFE microporous membrane on the base material treated in step S7. The filter material prepared by the present application has high transverse breaking strength and longitudinal breaking strength, and excellent filtering efficiency.

Description

Technical Field

[0001] This invention relates to the field of filter material preparation technology, specifically a wear-resistant blended gradient needle-punched filter material and its preparation method. Background Technology

[0002] In the field of dust control in highly abrasive industries such as steelmaking, ore crushing, and casting, baghouse dust collector filter media faces severe lifespan challenges. The dust characteristics in these industries are extremely unique: not only is the concentration high, but the particles are also hard and angular, causing continuous erosion and wear on the filter material. While the mainstream ordinary polyester filter media on the market is relatively inexpensive, its abrasion resistance is severely insufficient. Under the continuous impact of high-speed dust, the fibers are quickly worn down, forming holes and leading to excessive emissions and failure. This situation is particularly common in processes such as ore crushing and steel sintering, where filter media often need to be replaced in less than six months, seriously affecting the stable operation of the dust collection system.

[0003] Besides wear and tear, high-concentration dust generates significant static electricity during filtration due to intense friction. Accumulation of this charge poses a substantial safety risk of dust explosion. In recent years, dust explosions caused by insufficient antistatic properties of filter media have been frequent, resulting in substantial losses for businesses. While some wear-resistant or antistatic improved products exist on the market, they often suffer from performance imbalances: overemphasizing wear resistance may sacrifice filtration accuracy or dust removal performance; and the addition of conductive fibers may be uneven or unsustainable, leading to a rapid decline in antistatic performance over time. This performance imbalance severely limits the effectiveness of filter media under high-wear conditions.

[0004] Existing products lack systematic optimization in structural design and material formulation, making it difficult to achieve a good balance among various performance aspects. Especially under extreme operating conditions, the wear resistance and antistatic properties of the filter media often cannot simultaneously meet requirements, posing a safety hazard. Many dust collection equipment manufacturers report that existing filter media products fail to meet customers' requirements for long-term stable operation of equipment. Frequent filter media replacements not only increase maintenance costs but also affect the normal operation of the main equipment. Furthermore, with increasingly stringent environmental protection requirements and dust emission standards, filter media failure directly leads to excessive emissions, exposing companies to the risk of environmental penalties.

[0005] Therefore, developing a filter material capable of high strength, durable antistatic properties, and high-efficiency filtration has become an urgent need in this application field. This new material requires systematic innovation across multiple dimensions, including fiber ratio, structural design, and post-processing techniques, to truly solve the problems of filter media lifespan and safety under high-wear conditions. Summary of the Invention

[0006] The purpose of this invention is to provide a wear-resistant blended gradient needle-punched filter material and its preparation method to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A method for preparing a wear-resistant blended gradient needle-punched filter material includes the following steps:

[0009] S1. After opening and mixing coarse denier polyester fibers and conductive fibers respectively, a first mixture is obtained; after opening and mixing fine denier polyester fibers and conductive fibers respectively, a second mixture is obtained.

[0010] S2. The first mixture obtained in step S1 is combed and laid into a mesh, and the outer layer is formed by air-flow mesh formation. The second mixture obtained in step S2 is combed and laid into a mesh, and the inner layer is formed by air-flow mesh formation.

[0011] S3. Using a mechanical meshing method, the outer layer and inner layer obtained in step S2 are pre-stitched together to form a substrate.

[0012] S4. Vacuum impregnate the substrate from step S3 in the impregnation solution for 1-2 hours;

[0013] S5. Treat the substrate treated in step S4 at 80-120℃ for 15-30 minutes.

[0014] S6. Apply the finishing agent to the substrate treated in step S5 by padding.

[0015] S7. Treat the substrate processed in step S6 at 150-200℃ for 3-5 minutes;

[0016] S8. The substrate processed in step S7 is singed and calendered, and finally a PTFE microporous membrane is laminated on the surface of the substrate to obtain the filter material.

[0017] The impregnation solution in step S3 contains modified nano-silica, modified nano-montmorillonite, epoxy resin emulsion, curing agent and γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0018] The modified nano-silica is carbon-coated nano-silica;

[0019] The modified nano-montmorillonite is obtained by treating nano-montmorillonite with a hexadecyltrimethylammonium bromide solution.

[0020] Furthermore, in step S1, the mass ratio between coarse denier polyester fiber and conductive fiber is 7:3, and the mass ratio between fine denier polyester fiber and conductive fiber is 7:3.

[0021] Furthermore, in step S1, the coarse denier polyester fiber has a fineness of 4-6 dtex, and the fine denier polyester fiber has a fineness of 0.5-1 dtex.

[0022] Furthermore, in step S1, the conductive fiber is a carbon black-coated polyester fiber with a fineness of 1-1.5 dtex.

[0023] Furthermore, the method for preparing the carbon-coated nano-silica is as follows: nano-silica is coated with polydopamine and then calcined under an inert gas.

[0024] Furthermore, the specific steps for treating the nano-montmorillonite with hexadecyltrimethylammonium bromide solution are as follows: the nano-montmorillonite is dispersed in a 0.5-1.5 wt% hexadecyltrimethylammonium bromide solution, then 0.1 mol / L hydrochloric acid is added dropwise to adjust the pH to 5-6, the reaction is carried out at 65-80℃ for 1-2 hours, and finally the mixture is washed with sufficient deionized water and dried at 50-60℃ for 8-12 hours.

[0025] Furthermore, the concentration of the epoxy resin emulsion is 8-12 wt%, and the curing agent is polyamide.

[0026] Furthermore, the mass ratio of the modified nano-silica, modified nano-montmorillonite, epoxy resin emulsion, curing agent and γ-(2,3-epoxypropoxy)propyltrimethoxysilane is 1:(0.5-2):(80-120):(2-3):(0.2-0.5).

[0027] A wear-resistant blended gradient needle-punched filter material is prepared by the above-mentioned method for preparing wear-resistant blended gradient needle-punched filter material.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1. The present invention uses two layers including fine denier polyester fibers and coarse denier polyester fibers, which work together to perform gradient needle punching, which not only improves the filtration efficiency, but also enhances the transverse tensile strength and longitudinal tensile strength of the filter material.

[0030] 2. The present invention uses conductive fibers in the filter material, which can quickly dissipate the static charge generated when filtering high concentrations of dust, thus fundamentally eliminating the risk of dust explosion;

[0031] 3. In step S4, the present invention introduces an impregnation process. The impregnation solution includes modified nano-silica and modified nano-montmorillonite. The modified nano-montmorillonite and modified nano-silica form a point-to-surface bonded structure in the filter material, which increases the rigid sites in the filter material and improves the transverse and longitudinal tensile strength of the filter material.

[0032] 4. The nano-silica used in this invention is coated with carbon. The carbon coating can reduce the agglomeration between nano-silica particles, and the modified montmorillonite can reduce the stacking between montmorillonite particles, thus jointly promoting the improvement of the strength of the filter material. Attached Figure Description

[0033] Figure 1 This is a process flow diagram of the filter material preparation method of the present invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Please see Figure 1 The present invention provides:

[0036] Example 1

[0037] A method for preparing a wear-resistant blended gradient needle-punched filter material includes the following steps:

[0038] S1. 0.7 kg of coarse denier polyester fiber and 0.3 kg of conductive fiber are opened and mixed to obtain the first mixture. 0.7 kg of fine denier polyester fiber and 0.3 kg of conductive fiber are opened and mixed to obtain the second mixture. The fineness of the coarse denier polyester fiber is 5 dtex, the fineness of the fine denier polyester fiber is 0.8 dtex, and the conductive fiber is carbon black coated polyester fiber with a fineness of 1.2 dtex.

[0039] S2. The first mixture obtained in step S1 is combed and laid into a mesh, and the outer layer is formed by air-flow mesh formation. The second mixture obtained in step S2 is combed and laid into a mesh, and the inner layer is formed by air-flow mesh formation.

[0040] S3. Using a mechanical meshing method, the outer layer and inner layer obtained in step S2 are pre-stitched together to form a substrate.

[0041] S4. Vacuum impregnate the substrate from step S3 in the impregnation solution for 1.5 hours;

[0042] The impregnation solution in step S3 contains modified nano-silica, modified nano-montmorillonite, epoxy resin emulsion, curing agent and γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0043] The epoxy resin emulsion has a concentration of 10 wt%, and the curing agent is polyamide;

[0044] The mass ratio of modified nano-silica, modified nano-montmorillonite, epoxy resin emulsion, curing agent and γ-(2,3-epoxypropoxy)propyltrimethoxysilane is 1:1:100:2.5:0.4.

[0045] Modified nano-silica is carbon-coated nano-silica;

[0046] Modified nano-montmorillonite is obtained by treating nano-montmorillonite with hexadecyltrimethylammonium bromide solution. The specific steps are as follows: nano-montmorillonite is dispersed in 1wt% hexadecyltrimethylammonium bromide solution, the mass ratio of nano-montmorillonite to hexadecyltrimethylammonium bromide solution is 1:50, then 0.1mol / L hydrochloric acid is added dropwise to adjust the pH to 5.5, the reaction is carried out at 70℃ for 1.5h, and finally the mixture is washed with sufficient deionized water and dried at 55℃ for 10h.

[0047] S5. Treat the substrate processed in step S4 at 100°C for 25 minutes.

[0048] S6. Apply the finishing agent to the surface of the substrate treated in step S5 by padding, controlling the roll-out rate to 80%;

[0049] S7. Treat the substrate processed in step S6 at 180°C for 4 minutes;

[0050] S8. The substrate processed in step S7 is singed and calendered, and finally a PTFE microporous membrane is laminated on the surface of the substrate to obtain the filter material.

[0051] Example 2

[0052] A method for preparing a wear-resistant blended gradient needle-punched filter material includes the following steps:

[0053] S1. 0.7 kg of coarse denier polyester fiber and 0.3 kg of conductive fiber are opened and mixed to obtain the first mixture. 0.7 kg of fine denier polyester fiber and 0.3 kg of conductive fiber are opened and mixed to obtain the second mixture. The fineness of the coarse denier polyester fiber is 4 dtex, the fineness of the fine denier polyester fiber is 0.5 dtex, and the conductive fiber is carbon black coated polyester fiber with a fineness of 1 dtex.

[0054] S2. The first mixture obtained in step S1 is combed and laid into a mesh, and the outer layer is formed by air-flow mesh formation. The second mixture obtained in step S2 is combed and laid into a mesh, and the inner layer is formed by air-flow mesh formation.

[0055] S3. Using a mechanical meshing method, the outer layer and inner layer obtained in step S2 are pre-stitched together to form a substrate.

[0056] S4. Vacuum impregnate the substrate from step S3 in the impregnation solution for 1 hour;

[0057] The impregnation solution in step S3 contains modified nano-silica, modified nano-montmorillonite, epoxy resin emulsion, curing agent and γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0058] The epoxy resin emulsion has a concentration of 8 wt%, and the curing agent is polyamide;

[0059] The mass ratio of modified nano-silica, modified nano-montmorillonite, epoxy resin emulsion, curing agent and γ-(2,3-epoxypropoxy)propyltrimethoxysilane is 10.5:80:2:0.2.

[0060] Modified nano-silica is carbon-coated nano-silica;

[0061] Modified nano-montmorillonite is obtained by treating nano-montmorillonite with hexadecyltrimethylammonium bromide solution. The specific steps are as follows: nano-montmorillonite is dispersed in 0.5wt% hexadecyltrimethylammonium bromide solution, the mass ratio of nano-montmorillonite to hexadecyltrimethylammonium bromide solution is 1:50, then 0.1mol / L hydrochloric acid is added dropwise to adjust the pH to 5, the reaction is carried out at 65℃ for 1h, and finally the mixture is washed with sufficient deionized water and dried at 50℃ for 8h.

[0062] S5. Treat the substrate from step S4 at 80°C for 15 minutes;

[0063] S6. Apply the finishing agent to the surface of the substrate treated in step S5 by padding, controlling the roll-out rate to 70%;

[0064] S7. Treat the substrate processed in step S6 at 150°C for 3 minutes;

[0065] S8. The substrate processed in step S7 is singed and calendered, and finally a PTFE microporous membrane is laminated on the surface of the substrate to obtain the filter material.

[0066] Example 3

[0067] A method for preparing a wear-resistant blended gradient needle-punched filter material includes the following steps:

[0068] S1. 0.7 kg of coarse denier polyester fiber and 0.3 kg of conductive fiber are opened and mixed to obtain the first mixture. 0.7 kg of fine denier polyester fiber and 0.3 kg of conductive fiber are opened and mixed to obtain the second mixture. The coarse denier polyester fiber has a fineness of 6 dtex, the fine denier polyester fiber has a fineness of 1 dtex, and the conductive fiber is carbon black coated polyester fiber with a fineness of 1.5 dtex.

[0069] S2. The first mixture obtained in step S1 is combed and laid into a mesh, and the outer layer is formed by air-flow mesh formation. The second mixture obtained in step S2 is combed and laid into a mesh, and the inner layer is formed by air-flow mesh formation.

[0070] S3. Using a mechanical meshing method, the outer layer and inner layer obtained in step S2 are pre-stitched together to form a substrate.

[0071] S4. Vacuum impregnate the substrate from step S3 in the impregnation solution for 2 hours;

[0072] The impregnation solution in step S3 contains modified nano-silica, modified nano-montmorillonite, epoxy resin emulsion, curing agent and γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0073] The epoxy resin emulsion has a concentration of 12 wt%, and the curing agent is polyamide;

[0074] The mass ratio of modified nano-silica, modified nano-montmorillonite, epoxy resin emulsion, curing agent, and γ-(2,3-epoxypropoxy)propyltrimethoxysilane is 1:2:120:3:0.5

[0075] Modified nano-silica is carbon-coated nano-silica;

[0076] Modified nano-montmorillonite is obtained by treating nano-montmorillonite with hexadecyltrimethylammonium bromide solution. The specific steps are as follows: nano-montmorillonite is dispersed in 1.5wt% hexadecyltrimethylammonium bromide solution, the mass ratio of nano-montmorillonite to hexadecyltrimethylammonium bromide solution is 1:50, then 0.1mol / L hydrochloric acid is added dropwise to adjust the pH to 6, the reaction is carried out at 80℃ for 2h, and finally the mixture is washed with sufficient deionized water and dried at 60℃ for 12h.

[0077] S5. Treat the substrate from step S4 at 120°C for 30 minutes;

[0078] S6. Apply the finishing agent to the surface of the substrate treated in step S5 by padding, controlling the roll-out rate to 90%;

[0079] S7. Treat the substrate processed in step S6 at 200°C for 5 minutes;

[0080] S8. The substrate processed in step S7 is singed and calendered, and finally a PTFE microporous membrane is laminated on the surface of the substrate to obtain the filter material.

[0081] Comparative Example 1

[0082] The difference between Comparative Example 1 and Example 1 is that the addition of modified nano-silica in step S4 was omitted, while the remaining steps are exactly the same as in Example 1.

[0083] Comparative Example 2

[0084] The difference between Comparative Example 2 and Example 1 is that the addition of modified nano-montmorillonite in step S4 was omitted, while the remaining steps are exactly the same as in Example 1.

[0085] Comparative Example 3

[0086] The difference between Comparative Example 3 and Example 1 is that step S4 is completely omitted, while the remaining steps are exactly the same as in Example 1.

[0087] Comparative Example 4

[0088] The difference between Comparative Example 4 and Example 1 is that the coarse denier polyester fibers in the first mixture are replaced with the same weight of fine denier polyester fibers, while the rest of the steps are exactly the same as in Example 1.

[0089] Comparative Example 5

[0090] The difference between Comparative Example 5 and Example 1 is that the fine denier polyester fibers in the second mixture are replaced with the same weight of coarse denier polyester fibers, while the rest of the steps are exactly the same as in Example 1.

[0091] Comparative Example 6

[0092] The difference between Comparative Example 6 and Example 1 is that carbon-coated nano-silica was replaced with ordinary nano-silica, while the rest of the steps were exactly the same as in Example 1.

[0093] The finishing agent used in the above embodiments is a fluorinated finishing agent, specifically model LT-580;

[0094] In the above embodiments, the PTFE microporous membrane can be laminated with the substrate by means of hot pressing or other methods;

[0095] The preparation steps of the carbon-coated nano-silica used in the above embodiments are as follows: nano-silica is coated with polydopamine and then calcined under an inert gas. Specifically, nano-silica is ultrasonically dispersed in a Tris-HCl buffer solution containing dopamine hydrochloride. The pH of the buffer solution is adjusted to 8.5, and the reaction is carried out continuously for 12 hours. The concentration of dopamine hydrochloride is 20 mg / ml, and the mass ratio between nano-silica and Tris-HCl buffer solution is 1:40. After the reaction is completed, the mixture is filtered, and the filtered product is calcined at 800°C for 1 hour.

[0096] The filter materials prepared in Examples 1-3 and Comparative Examples 1-6 were subjected to performance tests, including mechanical property tests (including longitudinal tensile strength and transverse tensile strength) and filtration performance tests. The mechanical property tests were conducted according to GB / T3923.1 standard, and the filtration performance tests were conducted according to GB12625 standard. The test results are shown in Table 1 below:

[0097] Table 1: Performance test results of the filter materials prepared in Examples 1-3 and Comparative Examples 1-6

[0098]

[0099] As can be seen from the data in Table 1 above, the filter material prepared by the gradient needle punching method of setting fine denier polyester fibers in the inner layer and coarse denier fibers in the outer layer in this invention has improved transverse and longitudinal tensile strength compared to filter materials with both layers made of fine denier fibers. At the same time, its filtration capacity is significantly improved compared to filter materials with both layers made of coarse denier polyester fibers. In addition, in step S4 of this invention, the impregnation liquid includes modified nano-silica and modified nano-montmorillonite. The modified nano-montmorillonite and modified nano-silica form a point-to-surface bonded structure in the filter material, increasing the rigid sites in the filter material and improving the transverse and longitudinal tensile strength. In this invention, carbon-coated nano-silica is used to reduce the agglomeration of nanomaterials, and the introduction of the carbon layer further improves the strength of the filter material.

[0100] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a wear-resistant blended gradient needle-punched filter material, characterized in that, Includes the following steps: S1. After opening and mixing coarse denier polyester fibers and conductive fibers respectively, a first mixture is obtained; after opening and mixing fine denier polyester fibers and conductive fibers respectively, a second mixture is obtained. S2. After combing the first mixture obtained in step S1, lay it on a mesh and form an outer layer by air-flow mesh formation. After combing the second mixture obtained in step S1, lay it on a mesh and form an inner layer by air-flow mesh formation. S3. Using a mechanical meshing method, the outer layer and inner layer obtained in step S2 are pre-stitched together to form a substrate. S4. Vacuum impregnate the substrate from step S3 in the impregnation solution for 1-2 hours; S5. Treat the substrate treated in step S4 at 80-120℃ for 15-30 minutes. S6. Apply the finishing agent to the substrate treated in step S5 by padding. S7. Treat the substrate processed in step S6 at 150-200℃ for 3-5 minutes; S8. The substrate processed in step S7 is singed and calendered, and finally a PTFE microporous membrane is laminated on the surface of the substrate to obtain the filter material. The impregnation solution in step S3 contains modified nano-silica, modified nano-montmorillonite, epoxy resin emulsion, curing agent and γ-(2,3-epoxypropoxy)propyltrimethoxysilane. The modified nano-silica is carbon-coated nano-silica; The modified nano-montmorillonite is obtained by treating nano-montmorillonite with a hexadecyltrimethylammonium bromide solution.

2. The method for preparing the wear-resistant blended gradient needle-punched filter material according to claim 1, characterized in that, In step S1, the mass ratio of coarse denier polyester fiber to conductive fiber is 7:3, and the mass ratio of fine denier polyester fiber to conductive fiber is 7:

3.

3. The method for preparing the wear-resistant blended gradient needle-punched filter material according to claim 2, characterized in that, In step S1, the coarse denier polyester fiber has a fineness of 4-6 dtex, and the fine denier polyester fiber has a fineness of 0.5-1 dtex.

4. The method for preparing the wear-resistant blended gradient needle-punched filter material according to claim 2, characterized in that, In step S1, the conductive fiber is a carbon black coated polyester fiber with a fineness of 1-1.5 dtex.

5. The method for preparing the wear-resistant blended gradient needle-punched filter material according to claim 1, characterized in that, The method for preparing the carbon-coated nano-silica is as follows: nano-silica is coated with polydopamine and then calcined under an inert gas.

6. The method for preparing the wear-resistant blended gradient needle-punched filter material according to claim 1, characterized in that, The specific steps for treating the nano-montmorillonite with hexadecyltrimethylammonium bromide solution are as follows: the nano-montmorillonite is dispersed in a 0.5-1.5 wt% hexadecyltrimethylammonium bromide solution, then 0.1 mol / L hydrochloric acid is added dropwise to adjust the pH to 5-6, and the reaction is carried out at 65-80℃ for 1-2 hours. Finally, after washing with sufficient deionized water, it is dried at 50-60℃ for 8-12 hours.

7. The method for preparing the wear-resistant blended gradient needle-punched filter material according to claim 1, characterized in that, The epoxy resin emulsion has a concentration of 8-12 wt%, and the curing agent is polyamide.

8. The method for preparing the wear-resistant blended gradient needle-punched filter material according to claim 1, characterized in that, The mass ratio of the modified nano-silica, modified nano-montmorillonite, epoxy resin emulsion, curing agent and γ-(2,3-epoxypropoxy)propyltrimethoxysilane is 1:(0.5-2):(80-120):(2-3):(0.2-0.5).

9. A wear-resistant blended gradient needle-punched filter material, characterized in that, It is prepared by the method for preparing wear-resistant blended gradient needle-punched filter material as described in any one of claims 1-8.

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