Composite filter material and method for making same

Abstract

The application relates to a composite filter material and a preparation method thereof, which comprises the following steps: 1) soaking glass fibers in an acid solution, heating to obtain pretreated glass fibers; 2) soaking polyether ether ketone fibers in a sodium stearate solution, heating and keeping warm, then heating and keeping warm to obtain pretreated polyether ether ketone fibers; 3) mixing the pretreated glass fibers and the pretreated polyether ether ketone fibers according to a mass ratio of (6-8):3, beating to obtain a slurry; the filament diameter ratio of the glass fibers to the polyether ether ketone fibers is 1:(5-20); 4) layering the slurry obtained in the step 3), taking the upper layer slurry, defibrating and standing to form a crude material; and 5) sizing the crude material obtained in the step 4) and heating and solidifying to obtain the material. Controlling the mass ratio of the glass fibers and the high-temperature-resistant fibers can increase the complexity of the material, further improve the pollution capacity of the material, and enable the material to be used in an environment of 250 DEG C.

Description

Technical Field

[0001] This invention belongs to the field of functional material preparation technology, and in particular relates to a composite filter material and its preparation method. Background Technology

[0002] Glass fiber is an inorganic non-metallic material with advantages such as good insulation, strong heat resistance, good corrosion resistance, and high mechanical strength. The mechanical strength of glass fiber is not affected when the operating temperature is 300℃. Filter materials made from glass fiber as the main raw material have excellent high temperature resistance. However, because glass fiber is relatively hard and brittle, the tensile strength of the glass fiber materials is poor, making them difficult to bend and easily damaged by external forces, thus reducing their service life.

[0003] Secondly, in existing composite filter materials with glass fiber as the main component, in order to enhance the performance of the material, a certain amount of various types of organic fibers are selected for doping. This can enhance some of the material's properties, but it will lead to a decrease in the filtration effect of the product. Summary of the Invention

[0004] In view of this, the main objective of the present invention is to provide a composite filter material with excellent flexural strength and filtration effect.

[0005] The objective of this invention and the technical problem it solves are achieved by the following technical solution. According to this invention, a method for preparing a composite filter material includes:

[0006] 1) Pretreatment of glass fiber: Immerse the glass fiber in an acidic solution, heat it, and dry it to obtain pretreated glass fiber;

[0007] 2) Pre-treatment of polyetheretherketone fiber: Immerse polyetheretherketone fiber in sodium stearate solution, heat and keep warm, then heat up, keep warm, and dry to obtain pre-treated polyetheretherketone fiber.

[0008] 3) Mix the pretreated glass fiber with the pretreated polyetheretherketone fiber at a mass ratio of (6-8):3, control the pH, add water and pulp to obtain the slurry;

[0009] The diameter ratio of the glass fiber to the polyetheretherketone fiber is 1:(5-20);

[0010] 4) Let the slurry obtained in step 3) stand and separate into layers, take the upper layer of slurry, loosen it, let it stand and shape it to obtain coarse material;

[0011] 5) Apply adhesive to the coarse material obtained in step 4), heat and cure it to obtain the material.

[0012] Preferably, the diameter of the polyetheretherketone fiber is 40–60 μm.

[0013] Preferably, the glass fiber diameter is 3–6 μm.

[0014] Preferably, in step 1), the pretreatment method for the glass fiber includes:

[0015] Immerse the glass fiber in a 10wt% acidic solution, heat to 55-65℃, keep warm for 3-4 hours, remove and air dry at room temperature.

[0016] Preferably, in step 2), the pretreatment method for polyetheretherketone fibers includes:

[0017] The polyetheretherketone fiber is immersed in sodium stearate with a mass concentration of 20-30 wt%. The temperature is first raised to 55-65℃ and kept at that temperature for 1.5-2.5 hours. Then the temperature is raised to 70-80℃ and kept at that temperature for 2.5-3.5 hours. The fiber is then removed and air-dried at room temperature.

[0018] Preferably, in step 3), after mixing, hydrochloric acid is added to adjust the pH to 3-4.

[0019] Preferably, step 4) specifically includes:

[0020] Let the slurry obtained in step 3) stand for 1-2 hours, take the upper layer of slurry, loosen it for 10-20 minutes, add sodium stearate with a mass concentration of 4%-6%, and let it stand to form.

[0021] The volume ratio of the upper slurry to sodium stearate with a mass concentration of 4% to 6% is (8 to 10): 1.

[0022] Preferably, in step 5), the method of applying the adhesive includes:

[0023] Glycerol and deionized water are mixed to obtain a mixture. Organosilicon resin adhesive is added to the mixture and stirred evenly. The mixture is then applied to the coarse material.

[0024] The volume ratio of glycerol to deionized water is 1:(3-5);

[0025] The volume ratio of the silicone resin adhesive to the mixture is 1:(2-3).

[0026] Preferably, the material is composed of glass fiber, polyetheretherketone fiber and silicone resin binder;

[0027] The diameter ratio of the glass fiber to the polyetheretherketone fiber is 1:(5-20);

[0028] The mass ratio of glass fiber to polyetheretherketone fiber is (5-7):3.

[0029] Preferably, the tensile strength of the composite filter material is 25.50 N / 15 mm to 28.50 N / 15 mm, which is capable of filtering dirt with a diameter ≥ 5 μm.

[0030] The objective of this invention and the technical problem it solves are further achieved by the following technical solution. According to this invention, a filter paper is made of the aforementioned material; the filter paper has a dirt-holding capacity of 75.0 g / m³. 2 ~82.0g / m 2 .

[0031] The objective of this invention and the solution to its technical problem are also achieved by the following technical solution. According to this invention, a carrier is provided, wherein a control system is provided, and a filter element is provided in the control system. The filter element is made by bending the filter paper.

[0032] By employing the above technical solution, the material and its preparation method proposed in this invention have at least the following advantages:

[0033] 1. The material of this invention comprises glass fiber and high-temperature resistant fiber, wherein the mass ratio of glass fiber to high-temperature resistant fiber is (6-8):3, which enables a sufficient amount of glass fiber to be wound around the high-temperature resistant fiber, thereby increasing the internal complexity of the material and enabling the material to have a dirt-holding capacity of 75.0 g / m³. 2 ~82.0g / m 2 It can be used in environments up to 250℃.

[0034] 2. The technical solution of this invention uses hydrophilic alkali-free glass fiber as the main raw material, and adds high-temperature resistant fibers. The resulting material can be used in an environment of 250°C. For the selection of high-temperature resistant fibers, this invention chooses one of asbestos fiber, polytetrafluoroethylene fiber, polyetheretherketone fiber, and ceramic fiber. These high-temperature resistant fibers have excellent high-temperature resistance, ensuring that the mechanical strength of the prepared material does not change in a high-temperature environment, thus exhibiting excellent high-temperature resistance. Specifically, this invention selects polyetheretherketone fiber. Polyetheretherketone fiber has excellent mechanical properties, high temperature resistance, corrosion resistance, flame retardancy, and high electrical insulation. The material prepared using polyetheretherketone fiber as a dopant not only does not produce various debris, but also compensates for the hardness and brittleness of glass fiber, thereby giving the material a certain tensile strength.

[0035] 3. The polyetheretherketone (PEEK) fiber used in this invention has a diameter of 40–60 μm. The ratio of the diameter of the glass fiber to that of the PEEK fiber is 1:(5–20), meaning the diameter of the glass fiber is smaller than that of the PEEK fiber. Since the diameter of the PEEK fiber is much larger than that of the glass fiber, during the preparation process, the smaller diameter glass fiber will cross-wrap with the larger diameter PEEK fiber, increasing the complexity of the internal structure of the material and thus increasing the material's dirt-holding capacity. The optimal diameter is 3–6 μm for the glass fiber. Secondly, the larger diameter PEEK fiber serves as the material's skeleton structure, thereby increasing the tensile strength of the material to 25.50 N / 15 mm to 28.50 N / 15 mm. This prevents the material from being torn due to the high pressure of the hydraulic oil during use, thus ensuring its functionality.

[0036] 4. In the treatment of polyetheretherketone (PEEK) fibers, this invention only uses sodium stearate for room temperature soaking, followed by two heating soaking processes. This improves the affinity of PEEK fibers for alkali-free glass fibers, thereby increasing the tensile strength of the product. Compared with PEEK fibers that do not undergo two heating soaking processes, the tensile strength is increased by 12% to 15%. This enhances the structural stability of the material under high pressure, preventing it from tearing easily and thus losing its filtering effect, making it unable to filter out oil stains, and causing the flight controller to malfunction.

[0037] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Detailed Implementation

[0038] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following detailed description, in conjunction with preferred embodiments, provides a detailed explanation of the specific implementation methods, features, and performance of a nitrogen-doped bamboo cellulose carbon aerogel electrode material and its preparation method according to the present invention. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable manner.

[0039] Unless otherwise specified, all materials or reagents listed below are commercially available.

[0040] This invention provides a method for preparing a composite filter material, the method comprising:

[0041] 1) Pretreatment of glass fiber: Immerse the glass fiber in an acidic solution, heat it, and dry it to obtain pretreated glass fiber;

[0042] 2) Pre-treatment of polyetheretherketone fiber: Immerse polyetheretherketone fiber in sodium stearate solution, heat and keep warm, then heat up, keep warm, and dry to obtain pre-treated polyetheretherketone fiber.

[0043] 3) Mix the pretreated glass fiber with the pretreated polyetheretherketone fiber at a mass ratio of (6-8):3, control the pH, add water and pulp to obtain the slurry;

[0044] The diameter ratio of the glass fiber to the polyetheretherketone fiber is 1:(5-20);

[0045] 4) Let the slurry obtained in step 3) stand and separate into layers, take the upper layer of slurry, loosen it, let it stand and shape it to obtain coarse material;

[0046] 5) Apply adhesive to the coarse material obtained in step 4), heat and cure it to obtain the material.

[0047] The mass ratio of glass fiber to high-temperature resistant fiber added in this invention is (6-8):3. The reason is that if the mass ratio of glass fiber to high-temperature resistant fiber is too low, there will be too few glass fibers wrapped around the high-temperature resistant fiber, resulting in a simple internal structure of the material, reduced tensile strength, and reduced dirt holding capacity. If the mass ratio of glass fiber to high-temperature resistant fiber is too high, on the one hand, the excessive amount of glass fiber will cause the material to become brittle. On the other hand, the excessive amount of glass fiber will cause glass fiber fragments to be flushed out during use, becoming filtered contaminants. This will not only scratch the inside of the hydraulic device, but also reduce the material's dirt holding capacity and affect its service life.

[0048] Therefore, controlling the mass ratio of glass fiber to high-temperature resistant fiber at (6-8):3 can effectively increase the internal structural complexity of the material and improve the utilization rate of raw materials, thereby increasing the tensile strength and dirt-holding capacity of the material and effectively extending its service life. Specifically, when the mass ratio of glass fiber to high-temperature resistant fiber is controlled at 7:3, the dirt-holding capacity reaches 81 g / m³. 2 .

[0049] In some embodiments, the diameter of the polyetheretherketone fiber is 40–60 μm.

[0050] Glass fibers are relatively hard and brittle, while adhesives with heat and oil resistance generally have high molecular density, and their cured products also exhibit hard and brittle macroscopic properties. Therefore, materials containing glass fibers and heat- and oil-resistant adhesives can also become hard and brittle, which is not conducive to bending and filter element manufacturing, and will also affect the service life. Therefore, in selecting polyetheretherketone (PEEK) fibers, this invention selects 40-60 μm PEEK fibers, which have a significantly different filament diameter from the 3-6 μm of glass fibers. By introducing large-diameter, high-toughness PEEK fibers, the tensile strength of the material can be effectively guaranteed. Furthermore, PEEK fibers themselves have excellent resistance to acids, alkalis, high temperatures, and oily liquids, thus ensuring that the heat resistance and oil resistance of the resulting material do not change significantly.

[0051] In some embodiments, the glass fiber diameter is 3–6 μm.

[0052] The diameter of glass fiber is inversely proportional to its tensile strength. That is, the smaller the diameter of the glass fiber, the stronger its tensile strength. Therefore, the glass fiber with a diameter of 3 to 6 μm used in this invention can effectively enhance the tensile strength of the product material. The glass fiber prepared by centrifugal spinning method can meet the requirements of this invention in terms of diameter.

[0053] Secondly, excessively high fiber diameter can affect the size of the filter, meaning it cannot filter out fine oil sludge contaminants. Therefore, using glass fibers with a fiber diameter of 3–6 μm can effectively remove oil sludge contaminants with a diameter ≥5 μm from hydraulic oil, thereby effectively improving the filtration effect of the material.

[0054] In some embodiments, step 1) includes a pretreatment method for the glass fiber comprising:

[0055] Immerse the glass fiber in a 10wt% acidic solution, heat to 55-65℃, keep warm for 3-4 hours, remove and air dry at room temperature.

[0056] The glass fiber used in this invention is a hydrophilic material, while the polyetheretherketone (PEEK) fiber is a hydrophobic material. In a conventional environment, the affinity between these two fibers is not strong. However, to achieve a tight bond between the hydrophilic alkali-free glass fiber and the hydrophobic PEEK fiber, this invention treats the surface of the alkali-free glass fiber with a 10wt% sulfuric acid solution. Sulfuric acid etching increases the surface area of ​​the alkali-free glass fiber, thereby improving its affinity with PEEK. Simultaneously, since the alkali-free glass fiber is prepared by centrifugal spinning, defects in the spinning process can lead to impurities. Pretreatment with a 10wt% sulfuric acid solution removes these impurities, thereby improving the tensile strength of the material.

[0057] Etching glass fibers with acidic solutions will inevitably lead to a decrease in the strength of the glass fibers. Therefore, in order to improve the tensile strength of the material, this invention selects alkali-free glass fibers. Compared with other glass fibers, alkali-free glass fibers can minimize the damage caused by using 10wt% acidic solution, thereby improving the tensile strength of the material.

[0058] In some embodiments, step 2) of the pretreatment method for polyetheretherketone fibers includes:

[0059] The polyetheretherketone fiber is immersed in sodium stearate with a mass concentration of 20-30 wt%. The temperature is first raised to 55-65℃ and kept at that temperature for 1.5-2.5 hours. Then the temperature is raised to 70-80℃ and kept at that temperature for 2.5-3.5 hours. The fiber is then removed and air-dried at room temperature.

[0060] When treating polyetheretherketone (PEEK) fibers, 20-30 wt% sodium stearate is added. Sodium stearate enhances the affinity of PEEK fibers for alkali-free glass fibers. Unlike conventional methods that simply soak PEEK fibers in sodium stearate at room temperature, this invention employs a two-stage heating and holding method. After placing the PEEK fibers in 20-30 wt% sodium stearate, the first heating and holding process ensures that the sodium stearate is fully dispersed, thereby allowing the surface of the PEEK fibers to be fully permeated. The process involves contacting sodium stearate in the first heating and holding phase, followed by a second heating and holding phase. This allows sodium stearate to develop an affinity for alkali-free glass fibers, thereby increasing the affinity between polyetheretherketone (PEEK) fibers and alkali-free glass fibers and improving the tensile strength of the material. Compared to materials prepared without this method (PEEK fibers obtained by soaking in sodium stearate at room temperature and then doping them with glass fibers treated with an acidic solution), the tensile strength is increased by 12% to 15%.

[0061] In some implementations, in step 3), after mixing is complete, hydrochloric acid is added to adjust the pH to 3-4.

[0062] This invention uses hydrochloric acid to adjust the pH to 3-4, which can make the slurry uniform and avoid excessive settling during molding, thus preventing material damage.

[0063] In some implementations, step 4) specifically includes:

[0064] Let the slurry obtained in step 3) stand for 1-2 hours, take the upper layer of slurry, loosen it for 10-20 minutes, add sodium stearate with a mass concentration of 4%-6%, and let it stand to form.

[0065] The volume ratio of the upper slurry to sodium stearate with a mass concentration of 4% to 6% is (8 to 10): 1.

[0066] In the pulp forming stage, sodium stearate is added. At this time, the concentration of sodium stearate is 4% to 6%, and the volume ratio of pulp to added sodium stearate is (8 to 10): 1. Since hydrochloric acid is added in step 3) to adjust the pH to 3 to 4, the pulp solution is acidic at this time, while sodium stearate is alkaline. Therefore, the pH of the solution system will change when sodium stearate is added. If the pH change is too large, the reaction will be too violent, which will affect the uniformity of paper forming. Therefore, this invention controls the concentration of sodium stearate to 4% to 6% and ensures that the volume ratio of pulp to sodium stearate is (8 to 10): 1, so as to make the pulp more uniform in the forming process, so that the fibers can be evenly distributed, thereby improving the tensile strength of the pulp.

[0067] In some implementations, step 5) involves applying the adhesive using the following methods:

[0068] Glycerol and deionized water are mixed to obtain a mixture. Organosilicon resin adhesive is added to the mixture and stirred evenly. The mixture is then applied to the coarse material.

[0069] The volume ratio of glycerol to deionized water is 1:(3-5);

[0070] The volume ratio of the silicone resin adhesive to the mixture is 1:(2-3).

[0071] In some embodiments, the material is composed of glass fiber, polyetheretherketone fiber, and silicone resin binder;

[0072] The diameter ratio of the glass fiber to the polyetheretherketone fiber is 1:(5-20);

[0073] The mass ratio of glass fiber to polyetheretherketone fiber is (5-7):3.

[0074] In some embodiments, the tensile strength of the composite filter material is 25.50 N / 15 mm to 28.50 N / 15 mm, which is sufficient to filter contaminants with a diameter ≥ 5 μm.

[0075] Another embodiment of the present invention provides a filter paper made of the above-mentioned material; the filter paper has a dirt holding capacity of 75.0 g / m³. 2 ~82.0g / m 2 .

[0076] Another embodiment of the present invention provides a carrier in which a control system is provided, and a filter element is provided in the control system, the filter element being made by bending the filter paper.

[0077] The technical solution of the present invention will be further described below through more specific embodiments. The density and flexural strength tested in the embodiments are both tested using methods conventional in the art.

[0078] Example 1

[0079] 1) Prepare 500 mL of 10 wt% dilute sulfuric acid solution, place 14 g of alkali-free glass fiber with a diameter of 5 μm in the dilute sulfuric acid solution, heat it to 60°C in an oil bath and keep it for 4 h, take it out and dry it at room temperature for 4 h to obtain the pretreated alkali-free glass fiber.

[0080] 2) Place 6g of 50μm polyether ether ketone fiber in 1L of 25wt% sodium stearate, heat it to 60℃ in an oil bath and keep it for 2h, then raise the temperature to 75℃ and keep it for 3h, take it out and dry it at room temperature for 4h to obtain the pretreated polyether ether ketone fiber.

[0081] 3) Mix the pretreated alkali-free glass fiber with polyetheretherketone fiber, add 5L of water, adjust the pH to 3.5 with hydrochloric acid, mix evenly, and then place in a pulper and pulp for 30 minutes.

[0082] 4) Place the prepared slurry in the headbox and let it stand for 2 hours. Then, take 1L of the upper slurry and place it in the descaling machine. Descaling for 15 minutes, add 0.11L of 5% sodium stearate, let it stand for 30 minutes, and then put it into the molding machine to form the coarse material.

[0083] 5) Mix glycerol and deionized water at a volume ratio of 1:4 to obtain a mixture. Add silicone resin adhesive SH-9608 to 100mL of the mixture and mix evenly. Apply the adhesive to the coarse material and heat it at 220℃ for 2 hours to obtain the finished material.

[0084] The prepared material was subjected to tensile strength testing (GB / T453), and the tensile strength was 27.63 N / 15 mm, which is sufficient to filter dirt with a diameter ≥ 5 μm.

[0085] The dirt holding capacity of the filter paper prepared using this material was tested (GJB3820), and its dirt holding capacity was 80.2 g / m³. 2 It does not break when immersed in No. 15 hydraulic oil at 250℃ for a long time.

[0086] Example 2

[0087] 1) Prepare 500 mL of 10 wt% dilute sulfuric acid solution, place 11.2 g of alkali-free glass fiber with a diameter of 5 μm in the dilute sulfuric acid solution, heat it to 60°C in an oil bath and keep it for 3 h, take it out and dry it at room temperature for 3 h to obtain the pretreated alkali-free glass fiber.

[0088] 2) Place 4.8g of polyetheretherketone fiber with a diameter of 50μm in 1L of 25wt% sodium stearate, heat it to 60℃ in an oil bath and keep it for 2h, then raise the temperature to 75℃ and keep it for 3h, take it out and dry it at room temperature for 3h to obtain the pretreated polyetheretherketone fiber.

[0089] 3) Mix the pretreated alkali-free glass fiber with polyetheretherketone fiber, add 3L of water, adjust the pH to 3.5 with hydrochloric acid, mix evenly, and then place in a pulper and pulp for 30 minutes.

[0090] 4) Place the prepared pulp in the headbox and let it stand for 2 hours. Then, take 1L of the upper pulp and place it in the desoldering machine. Desolder for 15 minutes, add 0.11L of 5% sodium stearate, let it stand for 30 minutes, and then put it into the paper forming machine to form and obtain the coarse material.

[0091] 5) Mix glycerol and deionized water at a volume ratio of 1:4 to obtain a mixture. Add silicone resin adhesive SH-9608 to 120 mL of the mixture and mix evenly. Apply the adhesive to the coarse material and heat it at 220℃ for 2 hours to obtain the finished material.

[0092] The filter paper prepared using this material was tested for dirt holding capacity (GJB3820), and its tensile strength was 26.33 N / 15 mm, which means it can filter dirt with a diameter ≥ 5 μm.

[0093] The filter paper prepared using this material was tested for dirt holding capacity (GJB3820), and its dirt holding capacity was 76.4 g / m2. It did not break after being immersed in No. 15 hydraulic oil at 250℃ for a long time.

[0094] Example 3

[0095] 1) Prepare 1L of 10wt% dilute sulfuric acid solution, place 28g of alkali-free glass fiber with a diameter of 5μm in the dilute sulfuric acid solution, heat it to 60℃ in an oil bath and keep it for 4h, take it out and dry it at room temperature for 6h to obtain the pretreated alkali-free glass fiber.

[0096] 2) Place 12g of polyetheretherketone fiber with a diameter of 50μm in 2L of 25wt% sodium stearate, heat it to 60℃ in an oil bath and keep it for 2h, then raise the temperature to 75℃ and keep it for 3h, take it out and dry it at room temperature for 6h to obtain the pretreated polyetheretherketone fiber.

[0097] 3) Mix the pretreated alkali-free glass fiber with polyetheretherketone fiber, add 10L of water, adjust the pH to 3.5 with hydrochloric acid, mix evenly, and then place in a pulper and pulp for 30 minutes.

[0098] 4) Place the prepared pulp in the headbox and let it stand for 2 hours. Then, take 1L of the upper pulp and place it in the desoldering machine. Desolder for 15 minutes, add 0.11L of 5% sodium stearate, let it stand for 30 minutes, and then put it into the paper forming machine to form and obtain the coarse material.

[0099] 5) Mix glycerol and deionized water at a volume ratio of 1:4 to obtain a mixture. Add silicone resin adhesive SH-9608 to 100mL of the mixture and mix evenly. Apply the adhesive to the coarse material and heat it at 220℃ for 2 hours to obtain the finished material.

[0100] The prepared material was subjected to tensile strength testing (GB / T453), and the tensile strength was 28.45 N / 15 mm, which is sufficient to filter dirt with a diameter ≥ 5 μm.

[0101] The filter paper prepared using this material was tested for dirt holding capacity (GJB3820), and its dirt holding capacity was 79.6 g / m2. It did not break after being immersed in No. 15 hydraulic oil at 250℃ for a long time.

[0102] Example 4

[0103] 1) Prepare 1L of 10wt% dilute sulfuric acid solution, place 24g of alkali-free glass fiber with a diameter of 3μm in the dilute sulfuric acid solution, heat it to 55℃ in an oil bath and keep it for 3h, take it out and dry it at room temperature for 6h to obtain the pretreated alkali-free glass fiber.

[0104] 2) Place 12g of polyetheretherketone fiber with a diameter of 60μm in 2L of 20wt% sodium stearate, heat it to 55℃ in an oil bath and keep it for 1.5h, then raise the temperature to 70℃ and keep it for 2.5h, take it out and dry it at room temperature for 6h to obtain the pretreated polyetheretherketone fiber.

[0105] 3) Mix the pretreated alkali-free glass fiber with polyetheretherketone fiber, add 10L of water, adjust the pH to 3 with hydrochloric acid, mix evenly, and then place in a pulper and pulp for 20 minutes.

[0106] 4) Place the prepared pulp in the headbox and let it stand for 1 hour. Then, take 1L of the upper pulp and place it in the desoldering machine. Desolder for 10 minutes, add 0.11L of 5% sodium stearate, let it stand for 30 minutes, and then put it into the paper forming machine to form and obtain the coarse material.

[0107] 5) Mix glycerol and deionized water at a volume ratio of 1:3 to obtain a mixture. Add silicone resin adhesive SH-9608 to 100mL of the mixture and mix evenly. Apply the adhesive to the coarse material and heat it at 220℃ for 2 hours to obtain the finished material.

[0108] The prepared material was subjected to tensile strength testing (GB / T453), and the tensile strength was 28.07 N / 15 mm, which is sufficient to filter dirt with a diameter ≥ 5 μm.

[0109] The dirt holding capacity of the filter paper prepared using this material was tested (GJB3820), and its dirt holding capacity was 78.38 g / m³. 2 It does not break when immersed in No. 15 hydraulic oil at 250℃ for a long time.

[0110] Example 5

[0111] 1) Prepare 1L of 10wt% dilute sulfuric acid solution, place 32g of alkali-free glass fiber with a diameter of 6μm in the dilute sulfuric acid solution, heat it to 65℃ in an oil bath and keep it for 3.5h, take it out and dry it at room temperature for 6h.

[0112] 2) Place 12g of polyetheretherketone fiber with a diameter of 40μm in 2L of 30wt% sodium stearate, heat it in an oil bath to 65℃ and keep it for 2.5h, then raise the temperature to 80℃ and keep it for 3.5h, take it out and dry it at room temperature for 6h.

[0113] 3) Mix the pretreated alkali-free glass fiber with polyetheretherketone fiber, add 10L of water, adjust the pH to 4 with hydrochloric acid, mix evenly, and place in a pulper for 25 minutes.

[0114] 4) Place the prepared pulp in the headbox and let it stand for 1.5 hours. Then, take 1L of the upper pulp and place it in the desoldering machine. Desolder for 20 minutes, add 0.11L of 5% sodium stearate, let it stand for 30 minutes, and then put the pulp into the paper forming machine to form it and obtain the coarse material.

[0115] 5) Mix glycerol and deionized water at a volume ratio of 1:5 to obtain a mixture. Add silicone resin adhesive SH-9608 to 100mL of the mixture and mix evenly. Apply the adhesive to the coarse material and heat it at 220℃ for 2 hours to obtain the finished material.

[0116] The prepared material was subjected to tensile strength testing (GB / T453), and the tensile strength was 26.39 N / 15 mm, which is sufficient to filter dirt with a diameter ≥ 5 μm.

[0117] The dirt holding capacity of the filter paper prepared using this material was tested (GJB3820), and its dirt holding capacity was 80.56 g / m³. 2 It does not break when immersed in No. 15 hydraulic oil at 250℃ for a long time.

[0118] Comparative Example 1

[0119] Comparative Example 1 is a commercially available glass fiber filter paper. Its tensile strength (GB / T453) was 24.63 N / 15 mm, and its dirt holding capacity (GJB3820) was 71.63 g / m². 2 The device became clogged during use after being immersed in No. 15 hydraulic oil at 250℃ for an extended period of time.

[0120] The comparison shows that the composite filter paper prepared in Example 1 of this invention has a higher tensile strength than the filter paper made of glass fiber alone, and its dirt holding capacity is also higher than that of the filter paper in Comparative Example 1. This demonstrates that the use of polyetheretherketone fiber as a dopant material for alkali-free glass fiber in this invention can improve the tensile strength, dirt holding capacity, and service life of the composite filter paper. It also shows that the addition of polyetheretherketone fiber does not reduce the service life of the composite filter paper, but rather promotes it to a certain extent. Its service life is about 5-7% longer than that of the alkali-free glass fiber filter paper in Comparative Example 1.

[0121] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0122] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

[0123] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a composite filter material, characterized in that: Preparation methods include: 1) Pretreatment of glass fiber: Immerse the glass fiber in an acidic solution, heat it, and dry it to obtain pretreated glass fiber; 2) Pretreatment of polyetheretherketone (PEEK) fibers: Immerse the PEEK fibers in a sodium stearate solution with a mass concentration of 20-30 wt%, first heat to 55-65℃ and keep at that temperature for 1.5-2.5 h, then heat to 70-80℃ and keep at that temperature for 2.5-3.5 h, remove and air dry at room temperature to obtain pretreated PEEK fibers; 3) Mix the pretreated glass fiber with the pretreated polyetheretherketone fiber at a mass ratio of (6-8):3, control the pH, add water and pulp to obtain the slurry; The diameter ratio of the glass fiber to the polyetheretherketone fiber is 1:(5-20). 4) Let the slurry obtained in step 3) stand and separate into layers, take the upper layer of slurry, loosen it, let it stand and shape it to obtain coarse material; 5) Apply adhesive to the coarse material obtained in step 4), heat and cure it to obtain the material.

2. The method for preparing the material according to claim 1, characterized in that: The polyetheretherketone fiber has a diameter of 40–60 μm; the glass fiber has a diameter of 3–6 μm.

3. The preparation method according to claim 1, characterized in that: In step 1), the pretreatment method for glass fibers includes: Immerse the glass fiber in a 10wt% acidic solution, heat to 55-65℃, keep warm for 3-4 hours, remove and air dry at room temperature.

4. The preparation method according to claim 1, characterized in that: In step 3), after mixing, add hydrochloric acid to adjust the pH to 3-4.

5. The preparation method according to claim 1, characterized in that: Step 4) specifically involves: Let the slurry obtained in step 3) stand for 1-2 hours, take the upper layer of slurry, loosen it for 10-20 minutes, add sodium stearate with a mass concentration of 4%-6%, and let it stand to form; The volume ratio of the upper slurry to sodium stearate with a mass concentration of 4% to 6% is (8 to 10):

1.

6. The preparation method according to claim 1, characterized in that: In step 5), the method of applying the adhesive includes: Glycerol and deionized water are mixed to obtain a mixture. Organosilicon resin adhesive is added to the mixture and stirred evenly. The mixture is then applied to the coarse material. The volume ratio of glycerol to deionized water is 1:(3-5); The volume ratio of the silicone resin adhesive to the mixture is 1:(2-3).

7. A composite filter material, characterized in that: The material is composed of glass fiber, polyetheretherketone fiber and silicone resin binder; The ratio of the diameter of the glass fiber to the diameter of the polyetheretherketone fiber is 1:(5-20); the diameter of the glass fiber is 3-6 μm. The mass ratio of glass fiber to polyetheretherketone fiber is (5-7):

3.

8. The composite filter material according to claim 7, characterized in that: The composite filter material has a tensile strength of 25.50 N / 15 mm to 28.50 N / 15 mm and can filter dirt with a diameter of ≥5 μm.

9. A filter paper, characterized in that: The filter paper is made of the material of claim 7; the filter paper has a dirt holding capacity of 75.0 g / m³. 2 ~82.0g / m 2 .

10. A vehicle, characterized in that: The carrier is equipped with a control system, and the control system is equipped with a filter element, which is made of the filter paper of claim 9 by bending.